Vascular

When a patient with an asymptomatic unruptured intracranial aneurysm is already on antiplatelet or anticoagulation therapy, the management is to continue[…] it — the risk of aneurysm rupture is less than the stroke/TIA risk from stopping.

This is supported by the ISUIA[…] Study, which counterintuitively showed patients on aspirin had a lower chance of rupture than those not on aspirin.

The PROTECT-U[…] trial is investigating ASA + intensive BP control for further risk reduction.

ISAT[…] established that coil embolization > surgical clipping for most unruptured symptomatic or ruptured aneurysms — now first-line. For aneurysms with anatomy that makes plain coiling unreliable (wide necks), adjunctive techniques are used: Balloon-Assisted Coiling (temporary balloon across the neck during deployment to prevent coil prolapse); Stent-Assisted Coiling (permanent stent across the neck for the same purpose).

Three features predict aneurysm recurrence after coiling: wide neck >4 mm, size >10 mm, and incomplete initial occlusion[…].

For wide-neck aneurysms specifically, Flow Diverters[…] are the most effective option.

Intrasaccular Flow Disruptors[…] (e.g., WEB-IT[…] trial) target wide-neck bifurcation aneurysms — most often at the MCA, Acomm, or basilar tip.

The STRIVE[…] criteria define six radiographic signatures of CSVD on MRI: Lacunar infarcts are the most common feature.

Round/ovoid, 3-15 mm[…] in diameter, classically in the putamen, caudate, thalamus, internal capsule, or pons.

Pathophys: healed infarct from rupture of a perforating[…] artery. Recent small (<20 mm) subcortical infarct. White matter hyperintensities (best on T2 FLAIR). Cerebral microbleeds (best on SWI). Widened perivascular spaces. Brain atrophy.

Five clinical lacunar syndromes: pure motor, pure sensory, sensorimotor, dysarthria-clumsy hand, and ataxic hemiparesis[…].

Thalamic infarcts are most commonly caused by occlusion of penetrating branches from the posterior cerebral artery (PCA)[…], especially the paramedian, inferolateral, or posterior choroidal branches.

Key board pearl: the artery of Percheron[…] is an anatomic variant where a single paramedian branch supplies BOTH thalami.

Occlusion produces a characteristic bilateral paramedian thalamic infarct[…] — often with vertical gaze palsy and impaired consciousness.

Clopidogrel irreversibly blocks the platelet P2Y12 ADP[…] receptor, inhibiting platelet aggregation for the ~7-10 day lifespan of the platelet. Hold 5-7 days before bleeding-risk procedures.

A subset of patients have CYP2C19[…] loss-of-function variants (common in Han-Chinese) which impair clopidogrel activation. CHANCE-2 showed ASA + ticagrelor is superior to ASA + clopidogrel in these patients.

Persistent unilateral headache and/or neck pain[…] with delayed onset of weakness after trauma should raise immediate suspicion for cervical carotid or vertebral artery dissection[…] with embolic stroke. The delay reflects time for an intramural hematoma to organize and embolize distally — neurologic symptoms often appear hours to weeks after the inciting event.

This cross-sectional MRI of the R ICA shows a carotid plaque surrounded by a rim of intraplaque hemorrhage[…] — a marker of plaque vulnerability that confers significantly increased risk of stroke recurrence[…] regardless of stenosis percentage.

Five classic lacunar syndromes from small-vessel infarcts in the basal ganglia, internal capsule, or pons: pure motor hemiparesis (most common), pure sensory, mixed sensorimotor, dysarthria-clumsy hand, and ataxic hemiparesis[…]. All produce contralateral deficits without cortical signs (no aphasia, neglect, or visual field cut), distinguishing them from cortical strokes.

Several landmark trials established and progressively extended the IV thrombolysis time window: NINDS[…]: foundational — established IV tPA at 0.9 mg/kg (10% bolus + 90% over 1 hour)[…]; ECASS III[…]: extended the window to 4.5 hours[…], only for patients without extensive ischemic changes on CT; WAKE-UP[…]: extended treatment for unknown-onset strokes if MRI shows DWI-FLAIR mismatch — pushing the treatable window up to 9 hours since LKN; BEST-MSU (mobile stroke units): showed dose-response benefit within the first hour of LKN.

IV thrombolytics work by activating fibrinolysis: tPA cleaves plasminogen → plasmin[…], which dissolves fibrin in clots.

Real-world efficacy: rtPA dissolves an LVO clot in only ~10-30[…]% of cases.

TNK (tenecteplase)[…] is increasingly preferred over tPA because of single-bolus administration, longer half-life, and greater fibrin specificity[…].

A growing exclusion from IV thrombolysis: prior use of factor Xa inhibitors[…] — can't be reliably reversed in time for safe lysis.

This image reveals a proximal L M1 MCA[…] occlusion, visible on both CTA and DSA.

The RACECAT[…] trial (Spain) tested prehospital triage — randomizing suspected LVO patients to direct transport to an EVT center vs nearest center for IV thrombolysis only.

Result: no difference[…] in 90-day disability. But this can't be cleanly extrapolated to the US — Spanish centers had faster IVT delivery AND US centers have faster EVT transport with newer technology, so the US tradeoff likely favors direct EVT-center transport more than the trial suggested.

EVT trials largely excluded NIHSS <6; 2 RCTs now testing it, both pending as of 2026:

ENDOLOW (N. America): NIHSS <6 within 8[…] hrs; MOSTE (Europe): NIHSS <6, within 24[…] hrs. Until they report, individualize on: disabling deficit (aphasia, hand weakness), expected trajectory, vascular anatomy

The original 2015 EVT trials used a 6[…]-hour LKN window. Three trials extended this dramatically:

DEFUSE 3[…] (LKN 6-16 hr[…]): selected by perfusion imaging — eligible if ischemic core <70 cc AND core-to-penumbra mismatch >1.8x, with absolute mismatch volume >15 cc; DAWN[…] (LKN 6-24 hr[…]): no penumbra mismatch required; uses age-stratified clinical-radiographic criteria (younger patients can have larger cores); AURORA[…] (2022): meta-analysis of 6 late-window EVT studies — confirmed durable benefit in the 6-24 hr window.

The MR CLEAN LATE and RESILIENT Extend[…] trials are now testing late-window EVT selected WITHOUT relying on CTP.

The HERMES[…] collaboration (2016) was a pooled analysis of the five 2015 landmark LVO EVT trials, all of which used a <6-hour LKN window.

Key finding: lower odds of favorable outcome the longer treatment was delayed — benefit dwindling around 7 hours[…] since LKN.

The five pooled trials: MR CLEAN, ESCAPE, SWIFT PRIME, EXTEND-IA, REVASCAT[…].

For more distal vessels (MeVO/DEVO), the DISTAL[…] trial is currently comparing EVT to medical management.

Cardioembolic stroke accounts for ≥30[…]% of all AIS. AFib is the most common etiology. Valvular AFib — AFib in the setting of moderate-severe mitral stenosis or a mechanical valve replacement.

Treatment is warfarin only[…]; DOACs are contraindicated.

Supported by the RE-ALIGN[…] trial, which compared dabigatran vs warfarin in AFib + mechanical heart valve patients and was stopped early due to worse bleeding AND embolic complications in the dabigatran arm.

Nonvalvular AFib is the dominant cardioembolic stroke etiology. Treatment is a DOAC[…] for most patients; LAA closure (e.g., WATCHMAN) is reserved for patients who cannot tolerate long-term anticoagulation.

Risk is quantified by the CHA₂DS₂-VASc[…] score: CHF / HTN / A₂ Age ≥75 (2 pts) / DM / S₂ prior Stroke or TIA (2 pts) / Vascular disease / A Age 65-74 / Sc Sex (female).

Anticoagulate if score ≥1 in men or ≥2 in women[…] — which captures essentially all patients with AFib + prior stroke.

Beyond CHA₂DS₂-VASc, additional risk markers help stratify: Lab biomarkers: elevated (2) NT-proBNP or HS-troponin[…]; Cardiac biomarkers: AFib burden, fibrosis, LA enlargement, LAA morphology.

Four landmark trials established DOACs as noninferior (often superior) to warfarin for nonvalvular AFib: RE-LY[…]: Dabigatran vs warfarin; ROCKET-AF[…]: Rivaroxaban vs warfarin; ARISTOTLE and ENGAGE[…]: Apixaban / Edoxaban vs warfarin.

A few nuances around anticoagulation in AFib + stroke: Parenteral AC bridging (heparin/LMWH): increases sICH[…] risk without reducing stroke risk — so don't bridge unless absolutely indicated. Recurrent stroke despite DOAC happens in ~1/4 to 1/3 of patients.

Switching DOACs does not[…] reduce this risk. Workup order: check anti-Xa levels for adherence → noncardiac workup → cardiac workup. Hypertensive Deep ICH + AFib is particularly tricky.

Ongoing trials: ASPIRE and ENRICH-AF[…] (DOAC vs ASA in these patients).

Antithrombotic strategy: PICSS[…]: warfarin vs ASA in PFO + stroke → no benefit to AC over AP; Post-hoc analyses of NAVIGATE-ESUS and RESPECT-ESUS in PFO patients showed DOAC > ASA; Meta-analysis of 4 trials comparing AP vs AC in PFO stroke: no difference → most patients treated with AP unless another AC indication.

PFO closure trials (a saga of negatives, then positives): Initial negative: CLOSURE I, PC, RESPECT (early version)[…]; Subsequent positive: CLOSE, GORE REDUCE, DEFENSE PFO[…]; Meta-analysis of patients with RoPE >7[…]: benefit of PFO closure confirmed. Practically: close PFOs in carefully selected high-RoPE patients with high-risk anatomic features.

Aortic arch atheromas cause stroke through artery-to-artery embolism[…].

High-risk features: atheroma >4 mm[…], ascending aorta location, mobile or ulcerated morphology.

Diagnosis: TEE[…] > TTE; emerging modalities include cMRI and cardiac CT.

Treatment: the ARCH[…] trial showed warfarin had HIGHER stroke AND bleeding risk vs ASA+Plavix → DAPT-based regimens preferred. Short-term DAPT (up to 30 days) per CHANCE/POINT/THALES criteria can be used in low-bleed-risk patients.

Ascending aortic dissection causes stroke via direct extension into the great vessels or embolic showering. Particularly common in connective tissue disorders: Marfan, Ehlers-Danlos type IV, familial thoracic aortic aneurysm, bicuspid AV, Loeys-Dietz[…].

Diagnosis: CTA aorta[…] (hemodynamically stable) or TTE[…] (unstable, bedside).

Treatment: emergent surgical repair[…]. Critically, IV thrombolysis is contraindicated — would worsen the dissection.

HFrEF causes embolic stroke through two pathophysiologies: LV thrombus formation and paroxysmal AFib[…].

Treatment if LV thrombus is present: warfarin for at least 3 months[…], then reassess with cardiac imaging.

Trial landscape: WARCEF[…] (HFrEF + sinus rhythm, warfarin vs ASA): lower stroke risk but higher bleed risk with warfarin — net neutral; NAVIGATE-ESUS[…] HFrEF subgroup post-hoc: lower stroke risk with rivaroxaban > ASA.

Stroke risk after MI peaks in the first 12 weeks[…], similar in STEMI ≈ NSTEMI.

Two settings warrant short-term anticoagulation: Anterior STEMI[…] (high LV thrombus risk from anterior wall akinesis): warfarin × 3 months; MI + documented LV thrombus[…] (with or without stroke): AC × 3 months minimum, with follow-up imaging.

Valvular heart disease causes stroke through several mechanisms; treatment varies by valve type and rhythm. Mechanical/Bioprosthetic heart valves (no AFib): warfarin[…] for 3-6 months[…] at INR goal 2.0-3.0 (aortic) or 2.5-3.5 (mitral)[…], then transition to antiplatelet therapy alone. Rheumatic heart disease: treat only if AFib is present.

With AFib + moderate-severe mitral stenosis → warfarin[…] (DOACs contraindicated; this is "valvular AFib").

Infective endocarditis (IE): stroke risk peaks between 4 mo before and 5 mo after diagnosis[…].: Diagnose with TTE; use modified Duke criteria[…]; Screen for mycotic aneurysms — may need DSA since CTA can miss small ones; Treatment: IV abx × 6 weeks[…] + valve surgery for paravalvular extension, poor abx response, or valve dysfunction with CHF.

Noninfective endocarditis (NIE): SLE → Libman-Sacks; Malignancy → Marantic[…] endocarditis (classic disseminated punctate infarct pattern); Treatment: address the underlying disease + antithrombotic therapy.

Left-sided cardiac tumors are an uncommon but important cardioembolic source: Atrial myxomas[…] — most common primary cardiac tumor; usually in the LA, attached to the interatrial septum; Papillary fibroelastomas[…] — small AV/MV-associated tumors; paradoxically more thrombogenic per unit size despite being smaller. Treatment for both is surgical excision; ASA may be added perioperatively.

Carotid (ICA) stenosis is classified as: Symptomatic[…]: stroke or TIA in the last <6 months attributable to that artery; Asymptomatic (symptoms >6 months ago, OR patient never had stroke/TIA).

Clinical pearl: nonlocalizing symptoms like dizziness, lightheadedness, syncope do NOT[…] count as symptomatic carotid stenosis.

Universal risk-factor management: BP control per SPRINT[…] trial: target <130/80; LDL control per TST[…] trial: target <70 (or <55 if DM or atherosclerosis in another bed); PCSK9[…] inhibitors as add-on if LDL still off goal; CREST-2 is refining BP/LDL targets.

Historical baseline: NASCET and ECST used ASA alone[…] for ICA stenosis.

Current paradigm: DAPT short-term (~21 days), then ASA alone[…] long-term.

Supporting trials: THALES: ASA + ticagrelor > ASA alone; CHANCE-2[…] (Han Chinese with CYP2C19 loss-of-function): ASA + ticagrelor > ASA + clopidogrel; Current guidelines: ASA + clopidogrel preferred over ticagrelor in most populations due to lower bleeding risk.

Carotid Endarterectomy (CEA): NASCET and ECST[…] established CEA's benefit by stenosis severity: 70-99[…]% stenosis → significant benefit; 50-69% → modest benefit; <50% → no benefit.

CEA vs Stenting (CAS): the CREST[…] trial found similar overall effectiveness but with increased periprocedural stroke risk in CAS.

CEA preferred for patients >70 years old[…] or revascularization within <1 week of stroke.

TCAR (TransCarotid Artery Revascularization)[…]: hybrid technique using CCA access with "flow reversal" to a femoral vein during stenting — reduces embolization. ROADSTER 2 Registry showed lower stroke/death rates than transfemoral CAS.

Asymptomatic carotid stenosis: the CREST-2[…] trial is comparing revascularization vs intensive medical therapy alone — results pending.

While awaiting CREST-2: Men[…] tend to benefit more from CEA than women (histologic differences: less collagen, more macrophage inflammation in male plaques); TCD can detect microemboli for risk stratification.

Complex carotid plaque imaging (newer MRI-based characterization): Lipid-rich necrotic core (LRNC); Fibrous cap morphology (FC); Calcification; Intraplaque hemorrhage[…] — confers very high stroke recurrence risk regardless of stenosis %.

Vertebral artery stenosis: no benefit[…] for stenting due to tortuosity[…] of the proximal vertebral artery. Treat medically. Intracranial Atherosclerotic Disease (ICAD): atherosclerosis in the distal ICA → MCA/ACA, or intracranial vertebrobasilar system → PCA.

Key trial: SAMMPRIS[…] showed stenting was inferior[…] to intensive medical management (DAPT × 90 days → ASA monotherapy indefinitely) in 70-99% ICAD. Stenting is now restricted to refractory cases.

Cerebral small vessel disease (CSVD) is dysfunction of small arteries, arterioles, venules, and capillaries[…] — producing lacunar strokes, white matter disease, microbleeds, and cognitive decline.

Risk factors: Modifiable: HTN, HLD, DM2, smoking; Less-emphasized but important: OSA and CKD[…] — both associated with more CMBs, WMHs, and silent infarcts; Non-modifiable[…]: older age.

The dominant CSVD pathophysiology is "arteriolosclerosis[…]" — loss of smooth muscle cells from the tunica media[…], leading to lipohyalinosis, microatheroma formation, and segmental arterial disorganization.

In CAA specifically, the parallel process is accumulation of amyloid-β[…] in vessel walls (predominantly leptomeningeal).

Non-atherosclerotic CSVD etiologies: Genetic: CADASIL, CARASIL; Autoimmune: Primary CNS vasculitis; Infectious: meningovascular syphilis; Iatrogenic: post-radiation[…] vasculopathy.

CAA[…] is a small-vessel disease driven by amyloid-β[…] deposition in cortical and leptomeningeal vessels — making them fragile and prone to chronic microhemorrhage and eventual symptomatic ICH. Clinical presentation: Progressive cognitive impairment.

Transient Focal Neurologic Episodes ("amyloid spells")[…] — short (<30 min) episodes mimicking TIA or focal seizure. Can be positive (paresthesias that spread) or negative (sudden weakness/language deficit).

MRI signature: Lobar CMBs[…] (contrast with the deep CMBs of hypertensive microangiopathy); Cortical superficial siderosis; Possible lobar ICH; Increased WMHs in the centrum semiovale.

Diagnosis: the Boston Criteria v2.0[…] now allow a "probable CAA" diagnosis without prior ICH in patients >50. Trials enrolling CAA patients with AFib: ASPIRE (Apixaban) and ENRICH-AF (Edoxaban).

CADASIL[…] is an autosomal dominant small-vessel disease driven by mutations in NOTCH3[…] on chromosome 19. Pathophysiology: NOTCH3 is normally expressed in vascular smooth muscle cells. The mutant protein causes BV wall thickening and luminal stenosis.

Smooth muscle cells degenerate with granular deposits that stain acid-Schiff(+) in the tunica media[…], plus collagen/fibrous accumulation in the adventitia.

Classic clinical triad: Migraine with aura[…] — often the first manifestation, typically in the 3rd decade; Recurrent subcortical strokes or TIAs; Progressive cognitive decline (often with acute confusional or psychiatric episodes).

MRI signature: WMHs classically in the external capsule and anterior temporal poles[…]; Silent lacunar strokes; CMBs in subcortical areas (>½ of patients). Diagnosis: Genetic testing for NOTCH3 (first-line).

If unavailable or negative, skin biopsy showing granular osmiophilic material (GOM)[…] in small vessels on electron microscopy.

CARASIL[…] is the autosomal recessive counterpart to CADASIL, caused by mutation in HTRA1[…] gene. Two extra-neurologic clues that distinguish CARASIL from CADASIL: spondylosis deformans (degenerative spine changes) and alopecia (premature hair loss).

CVT presents very differently from arterial stroke. Five clinical patterns to recognize: Increased ICP symptoms: headache (often dominant), N/V, papilledema; Focal neurologic deficit — unlike arterial strokes (maximal at onset), CVT deficits are typically progressive and often bilateral[…] (reflecting bilateral territories drained by midline sinuses); Seizures[…] — markedly more common at initial presentation than with arterial strokes; Subacute AMS; Cavernous sinus[…] syndrome — multiple cranial neuropathies (CN III, IV, V₁, V₂, VI). The "progressive + bilateral + headache + seizure" pattern should make you think venous rather than arterial.

Anticoagulation is first-line, even in the presence of venous infarct/hemorrhage: Acute: UFH or LMWH[…]; Provoked CVT (clear precipitant — infection, OCP, pregnancy): 3-6 months[…]; Unprovoked CVT: 6-12 months.

DOAC vs warfarin landscape (DOACs increasingly used): RE-SPECT CVT, EINSTEIN-Jr, DOAC-CVT[…]: validated DOACs for CVT; Ongoing: SECRET (rivaroxaban) and RWCVT (rivaroxaban vs warfarin).

Endovascular therapy: the TO-ACT[…] study randomized EVT+AC vs AC alone — inconclusive. EVT reserved for refractory cases with neurologic deterioration despite AC.

CAD occurs in the carotid or vertebral[…] arteries — predominantly in the extracranial segment, often precipitated by trauma.

Carotid: Traumatic[…]: a few cm above the carotid bifurcation, in the distal 2/3 of the extracranial ICA near the skull base; Spontaneous (typically more proximal in the ICA).

Vertebral: Traumatic[…]: typically affects the V3 segment[…] (between transverse process of C2 and the foramen magnum) — the most mobile, vulnerable segment; Some involve V2 (between transverse processes of C2-C6).

Cervical artery dissection happens when a tear in the BV wall lets blood enter the wall itself. The location of the tear determines the clinical consequences

• Sub-intimal[…] tear (between intima and media) → blood creates a false lumen → intramural hematoma. Two stroke mechanisms: Artery-to-artery embolism; Complete narrowing of the true lumen → vessel occlusion → distal hypoperfusion.
• Sub-adventitial[…] tear (between media and adventitia) → blood spills outward → creates a pseudoaneurysm[…] that compresses adjacent structures: Headache and neck pain from local pain receptors; Horner syndrome[…] (sympathetic plexus on the ICA); Other cranial neuropathies (lower CNs near skull base).

A, B (CTA head/neck) (Left vertebral[…] artery dissection with narrowing to 0.9 cm[…] at the level of vertebra C3 (artery segment V2) — resolved on); D (repeat CTA at 4 months) (vessel recanalized); C (MRI DWI axial) (diffusion restriction in the L PICA[…] territory — the acute infarct that resulted).

CAD presentation can be nonspecific and sometimes mimics migraine[…] — high suspicion is required.

ICA dissection: Ipsilateral headache + partial Horner syndrome (ptosis + miosis, NO anhidrosis)[…] — because post-ganglionic sympathetic fibers to the face travel with the external carotid; Cranial neuropathies from local pseudoaneurysm compression; Stroke (when it happens) is in the anterior circulation[…], sometimes including the retina (CRAO).

Vertebral dissection: Ipsilateral neck pain — usually the dominant symptom; Stroke (when it happens) is in the posterior circulation[…]: brainstem, cerebellum, or rarely spinal cord; Rarely SAH[…] if the dissection extends or originates in the intracranial segment, where vessels lack the external elastic lamina + have a thinner tunica media/adventitia → more prone to pseudoaneurysm formation. Either type: sometimes pulsatile tinnitus.

Acutely: treat like any other stroke if appropriate: IV thrombolysis ± EVT; For dissections involving the intracranial segment[…], IVT is investigated more cautiously due to potential SAH risk from pseudoaneurysm rupture.

Chronically: AP and AC are equipoise[…]. Either warfarin or ASA is acceptable per AHA guidelines.

Supporting trials: CADISS and TREAT-CAD[…]: AP vs AC in carotid artery dissection — no difference (both underpowered).

Short-term DAPT (21 days) can be added if POINT or CHANCE criteria met: High-risk TIA with ABCD2 score >4[…], started within 12 hr (POINT[…]) or 24 hr (CHANCE).

Pediatric stroke is divided by timing: 

Stroke presentation in children often differs from adults — leading to delayed diagnosis. Seizures and altered mental status[…] (rather than focal weakness) dominate, because of heightened cortical excitability in the immature brain.

Perinatal stroke: Symptomatic seizure[…] (most common presentation); AMS with failure to meet developmental milestones.

Childhood stroke: Stuttering speech; Headache; Symptomatic seizure; Posterior circulation symptoms[…]: unsteady gait, N/V.

The pediatric hyperacute stroke treatment window mirrors adult guidelines: IV thrombolysis: IVT[…] <4.5 hours[…]; Endovascular therapy: EVT <6 hours[…].

Sickle cell disease (SCD) carries unique additional treatment: Emergent exchange transfusion[…] — first achieve Hgb >10 g/dL, then reduce HbS to 15-20%. Supportive measures: IV fluids to maintain perfusion, supplemental O₂ for goal SpO₂ >93%.

For secondary stroke prevention in children: Antiplatelet (ASA[…] at 3-5 mg/kg/day[…] for typical arterial strokes (clopidogrel as alternative)); Anticoagulation (for cardioembolic etiologies or thrombophilic conditions).

In SCD children whose TCD velocities have normalized after transfusion and have no arteriopathy or silent infarcts, the TWiTCH[…] trial showed that chronic exchange transfusions can be replaced with maximally-tolerated hydroxyurea.

Rupture risk for an unruptured intracranial aneurysm is quantified by the PHASES[…] score:

P Population: Japanese and Finnish[…] get extra points (genuinely higher rupture rates); H HTN; A Age >70; S Size >7 mm[…] — the strongest individual predictor; E Earlier SAH (prior SAH from another aneurysm); S Site — particularly MCA, ACA/Acomm, or Pcomm[…] territories. Higher score → higher annual rupture risk → stronger case for intervention.

Additional variables beyond PHASES that modify rupture risk: Daughter sac (irregular outpouching), documented growth, family history, or smoking[…]. Unruptured but symptomatic aneurysms behave differently.

Classic example: a Pcomm aneurysm compressing ipsilateral CN III[…] → producing pupil-involving third nerve palsy with vision symptoms.

These symptomatic aneurysms are considered good candidates for endovascular treatment[…] regardless of PHASES score, because the symptoms portend imminent rupture or persistent neurologic morbidity.

Treatment of truly asymptomatic unruptured aneurysms remains controversial — the procedural risk must be weighed against the very low annual rupture rate. The trial landscape: TEAM[…]: looked at coiling for asymptomatic aneurysms — halted early due to low recruitment; CURES[…]: comparing coiling vs clipping in asymptomatic aneurysms — showed no difference; CAM: comparing endovascular/surgical intervention vs conservative management. In current practice, asymptomatic aneurysms with high PHASES scores, family history, or documented growth get treated.

A cerebral arteriovenous malformation (AVM) is a tangle of arteries and veins called a "nidus[…]" with no intervening capillaries[…] — so arterial pressure is transmitted directly into the venous system, producing high-flow lesions prone to rupture. Etiologies: most AVMs are sporadic.

Inherited causes: Hereditary Hemorrhagic Telangiectasia (HHT)[…], aka Osler-Weber-Rendu — AD with skin telangiectasias, recurrent epistaxis, and GI bleeding. Mutations in ENG, ALK1, or SMAD4.

Capillary Malformation–AVM (CM-AVM) syndrome (mutation in RASA1[…]).

Presentation: AVMs most commonly present with ICH (from rupture)[…], followed by seizures and focal neurologic deficits.

Risk stratification uses the Spetzler-Martin[…] grading scale (1-5) — higher scores mean higher surgical morbidity.

The three components: AVM nidus size >3 cm; Location in eloquent cortex (motor, language, sensory, visual); Pattern of venous drainage[…] — particularly deep venous drainage.

The goal of AVM treatment is to close the nidus[…] and stop AV shunting.

Conservative medical management: the ARUBA[…] trial randomized patients with unruptured AVMs to intervention vs medical management — controversially found that intervention produced worse[…] outcomes than medical management in asymptomatic AVMs.

Endovascular embolization via transarterial or transvenous approach using liquid embolics: Polyvinyl alcohol; n-BCA (n-butyl cyanoacrylate)[…]; Ethylene vinyl alcohol copolymer (Onyx); TATAM trial: testing transvenous vs transarterial embolization. Other modalities: microneurosurgical resection, stereotactic radiosurgery (photons/protons cause local thrombosis over months).

Strokes in the brainstem (posterior circulation)[…] are more likely than supratentorial strokes to be DWI-negative[…] on initial MRI. The reasons: Small lesion volume in tightly packed brainstem nuclei; Imaging artifacts in the posterior fossa (susceptibility, motion). Clinical correlate: a negative MRI does NOT exclude brainstem stroke. Repeat imaging at 24-48 hours if clinical suspicion remains high.

Imaging of the extracranial ICA[…] is a Class I AHA/ASA recommendation for any patient with symptomatic anterior circulation[…] ischemic stroke — because of the proven benefit of revascularization (CEA or CAS) in high-grade carotid stenosis. The corollary: an anterior-circulation stroke workup without carotid imaging is incomplete.

How soon must pAFib be detected after a cryptogenic stroke for anticoagulation to be beneficial? The honest answer: unknown[…] — the minimum AFib burden or detection window required to outweigh bleeding risk has not been definitively established.

Trials informing practice: CRYSTAL-AF[…]: prolonged monitoring (insertable loop recorders) detects more AFib post-cryptogenic stroke; ARTESIA: apixaban reduces stroke risk in device-detected AFib lasting 6 min to 24 hr. Practice is increasingly to initiate AC for any device-detected AFib regardless of when discovered.

Children with sickle cell disease[…] should undergo routine screening with transcranial Doppler (TCD)[…] to measure cerebral blood flow velocity. Elevated velocities identify children at high stroke risk who benefit from preventive exchange transfusions — the STOP trial paradigm.

A deficit NOT captured by the NIHSS[…] but considered disabling enough to justify IVT is isolated hand weakness[…] — which can render someone unable to work or perform fine motor tasks despite an NIHSS of 0. The lesson: NIHSS is a screening tool but doesn't measure disability. Treat the patient, not the score.

For patients with a wake-up stroke[…] (unknown LKN), IVT can still be given if MRI shows a favorable DWI-FLAIR mismatch[…] — DWI+ but FLAIR-, suggesting symptoms began <4.5 hr prior. This is the WAKE-UP trial paradigm.

In acute ischemic stroke, IVT should be given at full dose[…] to all eligible patients — regardless of the feasibility or timing of planned EVT.

Because combined bridging therapy[…] (IVT + EVT) remains superior to thrombectomy alone — the five "withholding IVT" trials (SKIP, MR CLEAN NO-IV, SWIFT-DIRECT, DIRECT-SAFE, DIRECT-MT) all failed to show noninferiority of EVT-alone.

The effectiveness of EVT for AIS in patients with NIHSS <6[…] is currently unknown[…], because the major LVO EVT trials excluded patients with mild deficits. Ongoing trials filling this gap: ENDOLOW (North American) and MOSTE (European).

In patients with AFib + moderate-to-severe mitral stenosis, the indicated therapy is warfarin[…] — because this is "valvular AFib[…]" and DOACs are contraindicated. Supported by RE-ALIGN: worse bleeding AND embolic outcomes with dabigatran vs warfarin in mechanical valve patients.

NT-proBNP[…] is a biomarker of atrial dysfunction[…], associated with: Higher overall ischemic stroke risk; Higher AFib detection rates after cryptogenic stroke (suggesting subclinical atrial cardiopathy); Eligibility for trials in the atrial cardiopathy / ESUS space (e.g., ARCADIA).

The presence of an atrial septal aneurysm[…] or a large R-to-L shunt[…] increases the likelihood that a PFO is pathogenic (causal) rather than incidental in ischemic stroke. These are the high-risk anatomic features incorporated into the PASCAL classification — and the population most likely to benefit from PFO closure.

In patients with ischemic stroke and documented LV thrombus[…], short-term anticoagulation is indicated: Agent: typically warfarin[…] (vitamin K antagonist); Duration: 3 months minimum, with follow-up imaging to guide whether to extend. DOACs are increasingly used off-label here based on emerging data, but warfarin remains the trial-supported standard.

In a patient presenting with ischemic stroke due to acute ascending aortic dissection[…] without atherosclerotic risk factors, Marfan syndrome[…] should be considered — Marfan predisposes to aortic root dilation and dissection via cystic medial degeneration from FBN1 mutation. Other CTDs to consider: Ehlers-Danlos type IV, Loeys-Dietz, familial thoracic aortic aneurysm syndrome.

After a high-risk TIA[…] or minor ischemic stroke: Start DAPT with ASA + clopidogrel[…]; Initiate within 12-24 hours of symptom onset; Continue for 21-90 days[…]; Then transition to single antiplatelet (typically ASA) long-term.

This is the POINT / CHANCE[…]-era paradigm: short-term DAPT reduces recurrent stroke risk; long-term DAPT increases bleeding without further benefit.

In the CREST[…] trial, CEA was associated with a higher rate of perioperative myocardial infarction[…], whereas CAS carried a higher risk of perioperative stroke[…]. Composite endpoint (stroke + MI + death) was similar overall. Clinical implication: choose modality based on patient profile — CEA for patients who tolerate surgical stress, CAS for patients at high cardiac risk. TCAR is emerging as a third option that mitigates both risks.

Small, round hypointense[…] lesions on GRE / SWI[…] (but isointense on T1, FLAIR, DWI) = cerebral microbleeds (CMBs).

Two distributions point to different etiologies: Deep CMBs (basal ganglia, thalamus, brainstem): chronic hypertensive microangiopathy; Lobar[…] CMBs (cortical/subcortical): CAA.

Lacunar infarcts[…] most commonly occur in the putamen of the basal ganglia[…], followed by thalamus, pons, internal capsule, and subcortical white matter — all locations supplied by penetrating small perforating arteries. Mechanism: lipohyalinosis or microatheroma in these tiny end-vessels → focal infarct → classic lacunar syndromes.

In an elderly patient with transient focal neurologic symptoms ("amyloid spells") and MRI findings of cortical superficial siderosis or lobar microbleeds[…], the most likely diagnosis is CAA[…] (cerebral amyloid angiopathy). Pathology: amyloid-β deposition in cortical and leptomeningeal vessels → vessel fragility → recurrent lobar hemorrhage and microbleeds.

Two contrasting presentation patterns: Arterial stroke: focal deficits maximal at onset[…], typically unilateral.

Cerebral venous thrombosis: deficits typically progressive or fluctuating[…], with headache/seizures/AMS more common, often bilateral due to midline sinus involvement. Key teaching point: "progressive deficit + headache + seizure" should prompt venous workup, not just arterial.

Treatment of vaccine-induced immune thrombotic thrombocytopenia (VITT)[…] presenting with CVT: IVIg + non-heparin anticoagulation[…] (argatroban, bivalirudin, fondaparinux).

What to AVOID: Heparin and antiplatelet[…] agents — would worsen the immune-mediated thrombosis (shares mechanism with HIT). VITT was classically described after adenoviral-vector COVID-19 vaccines, mediated by anti-PF4 antibodies.

Traumatic vertebral artery dissections most commonly involve the V3 segment[…] (transverse process of C2 to foramen magnum). Why V3?

This is the most mobile[…] part of the vertebral artery, with sharp turns around C1-C2 — making it vulnerable to rotational and hyperextension forces from whiplash, chiropractic manipulation, or sports trauma.

Most patients with cervical artery dissection[…] have subtle connective tissue[…] alterations on biopsy — but lack a defined hereditary connective tissue disease. This reflects a multifactorial vascular vulnerability that predisposes to dissection after minor trauma or even spontaneously — explaining why most CAD patients don't have a recognizable Marfan or EDS phenotype.

A key predisposing factor for spontaneous CAD is oral contraceptive[…] use.

Other contributors: migraine, recent infection, and pregnancy/peripartum[…] period. This reflects a non-atherosclerotic vascular vulnerability — many "spontaneous" CADs have a triggering exposure that wouldn't dissect a normal artery.

The CADISS[…] and TREAT-CAD[…] trials both demonstrated no significant difference[…] between antiplatelet therapy and anticoagulation for preventing recurrent stroke in spontaneous cervical artery dissection. Both approaches show similarly low event rates. In practice, AP vs AC is individualized based on bleeding risk, patient preference, and any concurrent indications.

Seizures[…] are a more common presenting feature of ischemic stroke in children[…] than in adults — due to heightened cortical excitability in the immature brain. This often leads to delayed stroke diagnosis in children, since seizures point clinicians toward primary epilepsy workup rather than vascular imaging.

In a previously healthy child, the most common cause of ischemic stroke is focal cerebral arteriopathy — an acute, unilateral inflammatory arteriopathy[…] often affecting the MCA and following a recent viral infection[…]. Distinct from chronic vasculopathies (moyamoya, sickle cell) — typically self-limited but can cause significant stroke during the active inflammatory phase.

In SCD children whose TCD velocities have normalized after a course of transfusions AND who have no arteriopathy or silent infarcts, the TWiTCH[…] trial showed that chronic exchange transfusions can be safely transitioned to maximally-tolerated hydroxyurea[…]. This is a meaningful QoL upgrade — hydroxyurea is oral, doesn't require iron chelation, and avoids the burden of chronic transfusions.

For children with arterial ischemic stroke who do NOT have sickle cell disease or a cardioembolic source: First-line: aspirin[…] at 3-5 mg/kg/day[…]; Alternative if ASA contraindicated: clopidogrel. The mechanism in these cases is most often focal cerebral arteriopathy or other post-infectious vasculopathy — antiplatelet therapy is the appropriate response.

The most common presentation of perinatal arterial ischemic stroke[…] is focal motor seizures[…], typically appearing within the first week of life — often clonic movements of one limb in an otherwise clinically stable neonate. Because the baby may seem otherwise well between seizures, perinatal stroke is often diagnosed only when imaging is obtained for the seizures themselves.

The size of the aneurysm[…] shows the strongest positive correlation with risk of rupture in unruptured intracranial aneurysms.

Rupture risk rises sharply for aneurysms larger than 7 mm[…], and is highest for posterior circulation[…] aneurysms or those with irregular morphology (e.g., daughter sacs, lobulation). Together, size + location + irregularity dominate the rupture-risk calculation — and are explicitly weighted in the PHASES score.

The ARUBA[…] trial randomized patients with unruptured AVMs to conservative medical management vs interventional treatment (surgery, embolization, or radiosurgery).

Counterintuitive result: the lowest incidence of death or symptomatic stroke occurred in the conservative medical[…] arm — interventional approaches were associated with a ~threefold higher risk during early follow-up. Caveats: short follow-up, AVMs that bled later may catch up, asymptomatic AVMs may behave differently from symptomatic ones. ARUBA changed but didn't end the debate.

The antiepileptic medication phenytoin[…] impairs neuroplasticity and motor recovery when given early after stroke, and is associated with poorer functional outcomes. For seizure prophylaxis or treatment in poststroke patients, prefer agents like levetiracetam or lamotrigine — which don't share this anti-plasticity effect.

During inpatient stroke rehabilitation, most improvement and independence are achieved in gait and mobility[…] — because intensive task-specific training and early mobilization drive faster recovery for these domains compared with self-care activities like bathing or dressing. Implication: prioritize early aggressive ambulation training in the rehab plan.

The intervention best supported by evidence to enhance motor recovery after stroke (in conjunction with standard exercise therapy) is implanted vagus nerve stimulation (VNS)[…], which promotes neuroplasticity. VNS pairs stimulation with movement tasks — driving Hebbian strengthening of motor circuits.

The VNS-REHAB[…] trial showed improved upper-limb motor function in chronic stroke patients.

Case: 67yo, L MCA syndrome, NIHSS 20. CTP: core 13 mL, mismatch ratio 8.5x, mismatch volume 97 mL. Would you offer EVT per DEFUSE 3?. Yes — meets all DEFUSE 3 thresholds: core 13 < 70 cc, mismatch ratio 8.5 > 1.8x, absolute mismatch volume 97 > 15 cc.[…]

Case: 74M, LKN 7 hr, R A2 stroke, NIHSS 11. CTP: core 4 mL, mismatch ratio 8.3x, mismatch volume 29 mL. Would you offer IVT per EXTEND?. Yes — meets EXTEND criteria: core 4 < 70 cc, mismatch ratio 8.3 > 1.2x, absolute mismatch volume 29 > 10 cc. Extended-window IVT (4.5-9 hr) appropriate.[…]

Case: 94M, LKN 12 hr, L MCA syndrome, NIHSS 18. CTP: core 108 mL, mismatch ratio 2.2x, mismatch volume 129 mL. Would you offer EVT per DEFUSE 3?. No — even though mismatch ratio (2.2x) and volume (129 cc) exceed thresholds, the core is too large (108 > 70 cc). DEFUSE 3 excludes core >70 cc.[…]. (In current practice, you might consider EVT under expanded large-core criteria — SELECT 2 / ANGEL-ASPECT — but DEFUSE 3 strictly says no.)

Case: 48M, LKN 6.5 hr, R MCA syndrome, NIHSS 19. CTP: core 24 mL, mismatch ratio 4.0x, mismatch volume 72 mL. Would you offer EVT?. Yes — within the DEFUSE 3 window (6-16 hr) and meets all criteria: core 24 < 70 cc, mismatch ratio 4.0 > 1.8x, mismatch volume 72 > 15 cc.[…]

A 2025 meta-analysis of four RCTs evaluated whether adjunctive MMA embolization[…] after surgery reduces chronic SDH recurrence: EMBOLISE, STEM, MAGIC-MT, EMPROTECT[…].

Result: combined recurrence/progression/reoperation rate 7.5% vs 15.5%[…] (NNT ~13) — favoring embolization.

Important nuance: three trials used liquid embolic agents[…] (Onyx, NBCA) and showed benefit.

The EMPROTECT[…] trial used microparticles and didn't reach significance — suggesting the embolic material itself matters.

For ICH in patients on antiplatelet therapy, the PATCH[…] trial showed that platelet transfusion in non-surgical patients led to worse[…] functional outcomes without reducing hematoma expansion or mortality — so transfusion is generally contraindicated.

The AHA/ASA[…] synthesis: avoid platelet transfusion in non-surgical antiplatelet-associated ICH, but consider it for patients undergoing neurosurgery (where a separate Chinese RCT suggested benefit).

The brain receives ~15[…]% of cardiac output, making it acutely vulnerable to cardiac dysfunction. Cardiac disease causes neurologic injury via two pathway families:

Embolic (structural defects or arrhythmias → blood stasis + endothelial injury → thrombus via Virchow's triad[…] (stasis + endothelial injury + hypercoagulability) → embolization to brain → silent infarcts or symptomatic strokes); Hypoperfusion (decreased CO → watershed infarcts[…] or global hypoxic-ischemic injury (e.g., after arrest)).

Fetal circulation: the L and R atria are normally connected via the foramen ovale[…] to shunt placental blood to the L heart, bypassing the lungs. After birth: lung pressure rises → LA pressure rises → foramen closes.

In 15-24[…]% of adults this closure is incomplete = persistent PFO.

Stroke mechanism: paradoxical embolism[…] — a venous thrombus (often DVT) crosses through the PFO RA → LA → LV → cerebral circulation, bypassing the lungs.

Step 1: rule out venous source — BLE venous Dopplers[…] for DVT.

Step 2: quantify likelihood with the RoPE score[…] (10-point scale). Points for absence of traditional vascular RFs, cortical infarct pattern, and younger age.

Interpretation: RoPE 0-3[…] → ~0% causal probability; RoPE 9-10[…] → ~88% causal probability.

Step 3: add anatomic features via PASCAL classification[…] — combines RoPE with high-risk PFO features (large shunt >20-30 bubbles, atrial septal aneurysm). Stratifies as unlikely / possible / probable using RoPE ≥7 + high-risk features for "probable."

Treatment: PFO closure[…]. Three early RCTs were negative (CLOSURE I, PC, RESPECT).

Three later RCTs and a meta-analysis showed benefit in high-risk patients: RESPECT Extended Follow-Up, GORE REDUCE, and CLOSE[…] (all 2017).

Consensus: close the PFO + give DAPT (ASA + clopidogrel) for 3-6 months[…] in high-RoPE, "probable" PASCAL patients.

Post-closure AFib: Early (<45 days)[…]: short-term DOAC; if no NSR conversion within 48 hr, switch to long-term AC; Late (>45 days): treat as primary AFib with long-term AC.

An ASD is a congenital defect with absent tissue in the interatrial septum causing bidirectional atrial blood flow. Types: ostium secundum (most common, fossa ovalis, predominantly female, highest paradoxical embolism risk), ostium primum, sinus venosus[…].

ASDs are usually larger[…] than PFOs and more likely to cause hemodynamic effects. With Valsalva → transient R-to-L shunting → paradoxical embolism.

Eventually, chronic L-to-R shunting → RV overload + reduced LV preload → atrial remodeling → increased AFib[…] risk → cardioembolic stroke.

Diagnosis: TEE[…] is required (TTE can't reliably distinguish ASD from PFO). Treatment: ASD closure + arrhythmia management.

In ischemic or non-ischemic cardiomyopathy leading to HFrEF[…], stroke risk is elevated through LV stasis and undetected pAFib.

Key trials: WARCEF[…]: HFrEF + sinus rhythm, ASA vs warfarin — no primary difference, but time-varying analysis suggested some warfarin benefit; COMMANDER-HF[…]: ischemic cardiomyopathy with EF <40%, low-dose rivaroxaban (2.5 mg BID)[…] + AP vs placebo + AP — no overall difference but 2021 post-hoc suggested benefit.

Cardiac encephalopathy[…] is a CHF complication producing decreased alertness, asterixis, and diffuse EEG slowing.

Mechanism is multifactorial: decreased cerebral perfusion, concurrent renal and hepatic[…] dysfunction (uremic/hepatic encephalopathy overlap), and chronic microembolism + hypoperfusion eventually leading to cognitive impairment / dementia in chronic CHF.

LV thrombus[…] forms via Virchow's triad in dysfunctional ventricles: stasis from reduced contractility, endocardial injury, and hypercoagulability/inflammation.

Diagnosis: TTE with bubble study — sensitivity is poor (~23%); TEE — useful adjunct but poorly visualizes the LV apex; Cardiac MRI (cMRI)[…] — highest sensitivity and specificity (gold standard).

Treatment: warfarin or DOAC (off-label) for at least 3 months[…]. Repeat imaging → if persistent thrombus, continue AC.

LVADs[…] are mechanical circulatory assist devices used in severe HFrEF — bridge to heart transplant or destination therapy.

Stroke mechanism: device pumping creates contact-induced clotting[…] (platelet activation/adhesion/aggregation + coagulation cascade activation from artificial surfaces) → embolization to brain.

Treatment: lifelong warfarin + antiplatelet therapy (regimen depends on subtype), targeting INR 2-3[…].

Valvular heart disease drives stroke risk through atrial remodeling that increases AFib risk. Treatment depends on valve type AND rhythm. Without AFib: Native valvular disease (non-rheumatic): antiplatelet[…] alone is sufficient; Surgical bioprosthetic: warfarin × 3-6 months[…] → then AP alone; TAVR/TAVI: DAPT or warfarin for at least 3 months[…]; Mechanical valve: lifelong warfarin (INR 2.0-3.0 AV, 2.5-3.5 MV); DOACs contraindicated.

With AFib: Native valvular disease: DOAC[…] first-line; Surgical bioprosthetic: warfarin × 3-6 months → long-term DOAC; Mechanical valve + AFib[…]: lifelong warfarin (INR 2.5-3.5 if MV).

Mechanical heart valves increase stroke risk through blood flow stagnation and platelet activation from shearing forces[…].

Anticoagulation: lifelong warfarin is required.: INR 2.0-3.0 for aortic, 2.5-3.5 for mitral[…]; DOACs contraindicated[…]. If thromboembolic event on therapeutic warfarin: intensify to INR 2.5-3.5, or add ASA. Bridge with heparin if INR drops below therapeutic range.

Why DOACs are out: the RE-ALIGN[…] trial randomized dabigatran vs warfarin in mechanical valve patients and was stopped early due to worse both bleeding AND embolic events with dabigatran.

Two cardiac tumors cause embolic stroke: Atrial myxomas[…] — most commonly arise from the interatrial septum. Two embolic mechanisms: surface thrombus formation OR direct tumor fragment embolization.

Neurologic complications: stroke, ICH (from BV walls weakened by tumor deposits) or SAH (from aneurysms formed at arterial walls)[…], syncope from LV outflow obstruction, seizures from cortical mets, AMS, spinal cord embolism.

Treatment: AC to prevent surface thrombus + surgical excision[…] — especially for left-sided tumors.

Papillary fibroelastomas[…] are benign/rare AV or MV tumors that can embolize → treat with surgical excision.

Acute management: Early antibiotics[…]; Valve surgery for severe valvular dysfunction, severe HF, recurrent systemic embolization, or persistent bacteremia despite abx; Timing pearl (delay surgery by at least 4 weeks[…] if the patient has had a large AIS or ICH; otherwise sooner is better).

Antithrombotic therapy: Avoid antithrombotic therapy[…] due to high hemorrhage risk; Even mechanical valve patients should have AC held for at least 2 weeks after endocarditis-related stroke; IV thrombolysis is contraindicated for AIS from endocarditis.

Mycotic aneurysms: Typically small → can escape CTA/MRA detection (pooled sens ~0.71); Use DSA[…] to diagnose, even after blood cultures clear; Preferred treatment: endovascular embolization > surgical clipping[…] (lower mortality, better access, fewer hemorrhagic complications).

AFib[…] is the most common arrhythmia.

Stroke mechanism: Loss of the atrial kick[…] → blood stasis in the LAA[…] (left atrial appendage); The LAA's complex trabeculated structure promotes thrombus formation when flow stagnates. Stroke risk magnitude: Nonvalvular AFib: ~5-fold increase; Valvular AFib: ~20-fold increase.

Treatment is rhythm-status-dependent: Nonvalvular AFib → DOAC; Valvular AFib (mechanical valve or mod-severe MS) → warfarin; Factor XIa inhibitors[…] are emerging as next-generation agents under investigation.

Detecting AFib after cryptogenic stroke: CRYSTAL-AF[…]: insertable cardiac monitor or loop recorder vs standard monitoring — significantly higher AFib detection; ARTESIA[…]: apixaban reduced stroke/embolism risk in device-detected AFib lasting 6 min to 24 hr.

Other key trials: LAAOS-4[…]: testing LAA closure in high-risk AFib patients already on AC; EAST-AFNET 4[…]: early rhythm control (catheter ablation or antiarrhythmics) + AC reduced death/stroke/CHF hospitalization vs rate control alone in newly diagnosed AFib.

Atrial flutter[…] is created by a macroreentrant circuit around the tricuspid annulus[…].

ECG signature: the classic "sawtooth[…]" pattern in the inferior leads (II, III, aVF). Atrial flutter often co-exists with AFib and shares the same stroke mechanism — loss of organized atrial contraction → stasis. Treatment: AC with same indications as AFib + catheter ablation of the cavo-tricuspid isthmus for rhythm control.

Cardiac arrest[…] (PEA, asystole, VFib, pulseless VTach) causes brain injury in three temporal phases: **1.

No-flow[…] phase (zero CO during arrest): mitochondrial failure → ion pumps fail → loss of membrane potential → voltage-gated channels open → intracellular Ca²⁺[…] accumulates → activates destructive proteases. 2.

Low-flow[…] phase (during CPR): partially restored CO causes secondary injury via free radical formation and neuronal apoptosis. 3.

Reperfusion[…] phase** (after ROSC): additional secondary injury, worsened by seizures and hyperthermia. This three-phase model is why treatment focuses on preventing secondary injury after ROSC — the primary insult is already done.

MRI imaging timing: delay until >48 hours[…] from arrest, because ischemic changes on ADC peak at 3-5 days post-arrest.

Classic MRI findings (diffusion restriction) involve the most metabolically active structures: cortex (occipital and medial prefrontal), basal ganglia, thalami, hippocampi, cerebellum[…].

Targeted Temperature Management: TTM at 32-37.5°C × 24 hours[…] after arrest; Avoid TTM if (ICH, hemorrhagic shock, GCS >8, or hemodynamic instability despite pressors[…]); ICECAP[…] trial is evaluating the optimal duration of TTM.

Per Neurocritical Care Society recommendations: Sequence: Initial: EEG with TTM initiation; ~48 hours: wean sedation, obtain MRI brain + SSEPs; ~72 hours from ROSC/rewarming: motor exam + quantitative pupillometry[…], without confounding sedation.

Most reliable predictors of poor outcome: Absent pupillary light reflex[…] on pupillometry; Bilateral absence of the N20 cortical response[…] on SSEPs. Decently reliable predictor: MRI showing diffuse diffusion restriction across cortex and deep gray matter.

Other supportive poor predictors: burst-suppression or suppression on EEG, elevated NSE blood biomarker, absent motor exam or extensor posturing[…].

In preop screening for CABG, many patients have undiagnosed carotid stenosis. Screen with carotid duplex US[…] in high-risk patients (recent stroke/TIA, age >70, multivessel CAD, PAD, carotid bruits).

If significant stenosis is found: Symptomatic 70-99% → revascularize before CABG (do carotid procedure first[…] unless CABG is urgent); CEA preferred over CAS for symptomatic stenosis before CABG.

Important pearl: patients undergoing carotid stenting before CABG who maintained DAPT[…] through CABG (without discontinuation) had the worst outcomes due to perioperative bleeding.

The main driver of intraoperative stroke during cardiac surgery is manipulation of the aorta[…] during cannulation/cross-clamping → dislodges atherosclerotic plaque.

Avoidance strategy: anaortic off-pump "no-touch"[…] technique eliminates manipulation of the ascending aorta and avoids cardiopulmonary bypass. Watershed infarcts result from intraoperative hypoperfusion.

Maintain MAP 60-65[…] (or higher with prior stroke history). Risk factors: higher Cr, preop AFib, prior stroke, older age, longer surgery.

Adjunctive intraop LAA closure: LAAOS III[…] trial showed benefit during cardiac surgery in patients on AC. Neuromonitoring options: NIRS (brain tissue O₂), TCD (microemboli), EEG (ischemia signs).

New-onset AFib[…] is the most common arrhythmia after cardiac surgery — peaking on postoperative day 2[…], usually resolving spontaneously before discharge. Pre/postop ASA has been investigated to reduce stroke risk even without AFib.

Initiate AC if: AFib persists or recurs >2 days[…] after surgery, OR perioperative stroke occurred.

Three temporal patterns of post-cardiac-surgery cognitive impairment: Delirium[…] — first week post-op; Delayed neurocognitive recovery — improvement over the next 30 days; Postop neurocognitive disorder[…] — persists beyond 30 days, may be permanent. Higher risk: older age, baseline cognitive impairment, comorbidities, longer/more complex surgery, intraoperative hypotension.

Catheterization (e.g., PCI) causes stroke through: Embolization of atherosclerotic plaque while traversing the aortic arch[…]; Potential air microemboli[…] from saline/contrast injection. Treatment of cath-related stroke: consider IVT or EVT for eligible patients — same hyperacute paradigm as community-onset stroke.

TAVR/TAVI[…] has ~3[…]% periprocedural stroke risk — comparable to surgical AVR. Mechanism is similar to PCI: plaque dislodgement during catheter passage through the aortic arch and across the diseased valve. Embolic protection devices (cerebral filters) are increasingly used to capture debris.

Contrast-induced encephalopathy[…] can mimic stroke after catheterization — presenting with AMS, seizures, cortical blindness, or focal deficits.

Pathophysiology: neurotoxicity from iodinated contrast[…] that disrupts the BBB → cortical irritation.

Treatment: self-resolves[…] as the kidneys clear the contrast (hours to a few days). Supportive care; consider IV fluids to accelerate clearance. Key distinguisher from real stroke: rapid spontaneous improvement is the rule.

A patient with cardioembolic stroke — the imaging story: A (EKG) (AFib with RVR[…]); B (TTE) (biventricular systolic dysfunction with LA enlargement[…]); C (TEE) (thrombus within the LAA[…]); D (CTA head) (terminal ICA occlusion extending into L MCA[…]); E (DSA) (confirms tICA occlusion); F (DSA) (recanalization of the ICA after EVT); G (MRI brain T2 FLAIR) (L MCA territory infarct[…]).

A patient with IE showing both ischemic and hemorrhagic complications: A (MRI DWI) (R MCA territory infarct[…]); B (MRI DWI) (cortical/subcortical septic emboli[…] (scattered punctate pattern)); C (MRI SWI) (sulcal hypointensities concerning for SAH[…]); D (CTH) (R intraparenchymal hemorrhage); E (CTH coronal) (basilar artery mycotic aneurysm[…]); F (DSA) (confirms basilar tip mycotic aneurysm).

A patient with IE complications including ICH from mycotic aneurysm rupture: A (CTH) (L frontal IPH[…]); B (DSA) (L MCA mycotic aneurysm[…]); C (TEE) (posterior perivalvular abscess[…]); D (CTH) (IVH); E (CTA coronal) (L PCA aneurysm); F (3D angiography) (confirms L PCA aneurysm)

An LVO stroke from initial imaging through reperfusion: A (CTA) (hyperdense MCA sign[…] (clot in the vessel)); B (CTA) (L MCA occlusion (the cut-off)); C (CTP) (penumbra (green) vs core (purple) mismatch[…] ratio — qualifies for late-window EVT); D (pre-EVT angio) (L MCA occlusion with arrowheads pointing to a large parenchymal defect); E (post-EVT angio) (recanalization[…] of the vessel).

A patient developing hemorrhagic transformation after EVT: A (CTH coronal/axial, post-EVT) (hyperdensity in the area of prior stroke — could be contrast staining OR hemorrhage); B (CTH Dual Energy) (contrast extravasation[…] (iodine suppresses on dual energy)); C (CTH non-contrast 24hr post-EVT) (new hyperdensity consistent with hemorrhagic transformation, Heidelberg Classification PH2[…] (parenchymal hematoma type 2 — most severe form))

A patient with malignant cerebellar edema after posterior circulation LVO: A (CTH) (L cerebellar hypodensity); B (MRI DWI) (L cerebellar infarct with suspected hemorrhagic conversion and mass effect on the 4th ventricle[…]; scattered bilateral occipital infarcts consistent with embolic etiology); C (MRI SWI) (confirms hemorrhagic transformation); D (CTH 24hr) (new effacement of the 4th ventricle and obstructive hydrocephalus[…]); E (post-decompression CTH) (suboccipital craniectomy + L cerebellectomy + R EVD[…] placement). This pattern — posterior fossa stroke + obstructive hydrocephalus → surgical decompression — is the classic indication for posterior fossa surgery