Interventional Neurology

Saad Mir

Brijesh Mehta

CEREBRAL ANGIOGRAPHY

Indications: Gold standard for characterizing neurovascular anatomy & pathologies, e.g., aneurysms, arteriovenous malformations (AVMs), extra- & intracranial stenosis, other dzs of cerebral & spinal vasculature.

Endovascular devices: Extra- & intracranial uses, e.g., catheters, microcatheters, coils, guidewires, microwires, liquid embolic agents, clot retriever, stents, angioplasty balloons.

Preprocedural care

Pt evaluation: Procedure indications: diagnostic or therapeutic. Noninvasive vascular studies: CTA, MRA, TCDs. Clinical status: level of arousal, cognition, neurological deficits. Vitals: temperature, blood pressure, ICP, EVD settings/output. PMH, meds (aspirin, heparin, Coumadin, antibiotics), allergies (esp to prior contrast exposure), renal dz & DM (risk for nephrotoxicity).
Pt education: Explain procedure. Instruct to remain still (avoid motion artifact).
Informed consent: ˜2% risk of groin hematoma, retroperitoneal bleed, infxn, vessel rupture, dissection, vasospasm, stroke, paralysis, blindness, contrast allergy, kidney damage, radiation complications, death.
Preparation: NPO 8 h prior to procedure. Discontinue metformin 24 h before procedure. Resume only 2 days after procedure. In pts w/abnl renal function, consider IV bicarbonate 1 h prior to procedure, Mucomyst 600 mg, two doses q4h before & after procedure. Start heparin gtt (goal activated clotting time [ACT] 200-250) after sheath insertion for stenting/coiling cases.

Procedure techniques: Conscious sedation & local anesthesia given before catheters placed. For most angiography, the arterial or venous system accessed safely via the femoral artery or vein distal to inguinal ligament. Catheter navigated into aorta & up into cervical vessels under fluoroscopy. Contrast administered & x-rays taken to examine the vessels in the head or spine. Typically, both carotid arteries & both vertebral arteries are studied.

Postprocedural care: (1) Use closure device (Perclose or MynxGrip) vs. manual groin compression (if pediatric pt or pt w/significant atherosclerotic dz in femoral artery). (2) Serial neurologic exams. (3) STAT head CT for any exam change. (4) BP monitoring; goal based on procedure performed. (5) Keep pt legs straight for 6 h if using manual groin compression, 2 h post closure device. (6) Continue anticoagulation (heparin drip) × 12-24 h after stent placement or aneurysm coiling. (7) Resume antiplatelets (aspirin 81 mg & clopidogrel 75 mg) after stent placement or aneurysm coiling; maintain on aspirin lifetime; clopidogrel for 1.5-12 mo. (8) Upon d/c, pt should avoid heavy lifting or exercise × 10 days, avoid swimming × 5 days.

Follow-Up Angiogram
Stenting	6-mo, 12-mo, 5-yr postprocedure
Aneurysm embolization	3-mo, 12-mo, 3-yr postprocedure
AVM embolization	3-mo, 6-mo, annually postprocedure

NEUROVASCULAR DISEASES

ACUTE ISCHEMIC STROKE

Angiographic signs: (1) Intraluminal thrombus: Filling defect in lumen of opacified vessel; most common sites: extracranial ICA & MCA. (2) Vessel occlusion: Tapered narrowing or sharp termination of contrast column. (3) Slow antegrade flow w/delayed arterial emptying. (4) Slow retrograde filling through pial collateral vessels. (5) Nonperfused areas.

TICI score: (TICI: “thrombolysis in cerebral ischemia,” Stroke 2003;34:e109-e137). TICI 0: complete occlusion. TICI 1: minimal perfusion past occlusion. TICI 2a: partial recanalization w/<66% perfusion of vascular territory. TICI 2b: complete recanalization but perfusion is slow. TICI 3: complete recanalization w/normal perfusion.

Endovascular therapies

IA thrombolysis: a/w ↑ recanalization rates for ICA, M1/M2, BA occlusions. Total IA dose = ˜1/3 IV dose (b/c given locally). Advantages: can be used in postsurgical pts & sx onset ≤6-12 h (PROACTII, MRCLEAN, ESCAPE).

IV + IA thrombolysis: Multimodal Rx shown to result in better recanalization.

IA thrombectomy or thromboaspiration: Achieved most commonly w/stentrievers (Solitaire FR, Trevo XP) or Penumbra 5Max ACE aspiration catheter. Offers possibility of faster recanalization, ↑ recanalization rates, ↓ total thrombolytic dose (SWIFT, TREVO-2, ADAPT FAST).

Contraindications: (1) Pregnancy, (2) serum glucose <50 mg/dL, (3) excessive tortuosity of vessels precluding device delivery/deployment, (4) known hemorrhagic diathesis, (5) oral anticoagulation Rx w/INR >3.0, (6) heparin w/in 48 h & PTT >2 times normal, (7) platelet count <30,000/&mgr;L, (8) h/o severe allergy to contrast, (9) sustained SBP >185 mm Hg or DBP >110 mm Hg if pt received IV rt-PA, (10) CT showing sig. mass effect w/midline shift, (11) >50% stenosis of the artery proximal to the target vessel, (12) life expectancy <3 mo.

MAJOR ENDOVASCULAR STROKE THERAPY TRIALS

“PROACTII”: IA thrombolysis (JAMA 1999;282:2003): Inclusion criteria: Sx duration <6 h angiographic occlusion (TICI 0 or 1) of M1 or M2 MCA. Rx groups: IA r-pro-UK (9 mg over 2 h) + low-dose IV heparin vs. low-dose IV heparin alone. Median time to Rx: 5.3 h. Median NIHSS: 17. Outcomes: Recanalization (TIMI 2-3): IA 66% vs. control 18% p ≤ 0.001. 90-day mRS <2: IA 40%, control 25%, OR 2. Mortality: r-pro-UK 25% & control 27%. Complications: 9%, neurologic, anaphylaxis, bleeding. sICH: IA 10.9%, 3.1% control, p = 0.06. Caveats: ↑ sICH rate c/w trials of IV thrombolysis (2/2 ↑ baseline stroke severity).

“IMSIII”: IAT (thrombolysis ± thrombectomy) + IV thrombolysis vs. IV thrombolysis (NEJM 2013;368:893-903): Inclusion criteria: NIHSS >10 and/or radiographic vessel occlusion, sx duration <3 h, IV tPA administration. IAT w/in 5-7 h. Median NIHSS: 17. Rx groups: IV tPA + IAT (IA tPA +/- thrombectomy) vs. IV tPA (control).

Outcomes: Recanalization (TICI 2 + 3): IAT 86% vs. control 61%. 90-day mRS of ≤2: IAT 40.8% vs. control 38.7, not statistically significant. sICH: 6.9% IAT vs. 5.9% control p = 0.8. Procedural complications: 16.1%. Caveats: minimal use of newer, superior clot retrievers, no large-vessel occlusion required so 25% in Rx arm did not get IAT, trend toward better mRS w/↑ recanalization.

“SYNTHESIS”: IAT (thrombolysis ± thrombectomy) vs. IV thrombolysis (NEJM 2013;368:904-913.). Inclusion criteria: NIHSS >6 & sx duration ≤4.5 h, IAT w/in 6 h. Median NIHSS: 13. Rx arms: IAT (IA tPA +/- thrombectomy) vs. IV tPA (control). Outcomes: no recanalization data. 90-day mRS of ≤1: IAT 30.4% IAT vs. control 34.8%, not statistically significant. sICH: 6% in both groups. Caveats: no recanalization data, liberal NIHSS, no large-vessel occlusion requirement, no IV tPA in treatment group.

“MRRESCUE”: IA thrombectomy vs. standard care (NEJM 2013;368:914-923). Inclusion criteria: sx duration ≤8 h, +/- IV tPA, vessel occlusion, CT/MRI stratified by positive/negative penumbra pattern. Median NIHSS 17. Rx arms: IA thrombectomy vs. standard care. Outcomes: Recanalization: 67% IAT. 90-day mRS: 3.9 in both groups. sICH: 9% IAT vs. 6% control, p = 0.24. Caveats: up to 8 h after symptom onset, only two devices used, trend of better mRS w/↑ reperfusion/recanalization.

“MRCLEAN”: IAT (thrombolysis ± thrombectomy) + IV thrombolysis vs. IV thrombolysis (NEJM 2015;372:11-20). Inclusion criteria: sx duration ≤6 h, large-vessel ant. circ occlusion, NIHSS >2. Rx groups: IV tPA + IAT (IA tPA +/- thrombectomy) vs. IV tPA (control). Outcomes: 90-day mRS favored IAT, OR 1.67. TICI 2b/3 58.7% in IAT. 13% of IAT required cervical stenting & 9% had new vascular distribution strokes. Caveats: 16% in IAT arm received no rx, low recanalization %.

“ESCAPE”: IAT (thrombolysis ± thrombectomy) + IV thrombolysis vs. IV thrombolysis (publication pending). Inclusion criteria: sx duration ≤12 h, large-vessel ant. circ occlusion, NIHSS >5. Exclusion: large core infarct or poor collateralization in >50% of MCA distribution. Outcomes: being published 2015 but preliminary data are positive.

Guidelines: (1) Initiation of IAT w/in 6 h (MRCLEAN) to 12 h (ESCAPE) of sx onset for anterior circulation & up to 48 h for posterior circulation strokes. (2) No e/o ICH. (3) Large-vessel occlusion (ICA, ACA, MCA, PCA, VA, BA). (4) NIHSS >5. (5) Infarct size <33% of MCA territory on head CT (Stroke 2005;36:66). (6) MR DWI volume <70 mL (Stroke 2009;40:2046). (7) Coagulopathy (INR >1.7, PTT >45 s, plts <100 K) not a contraindication for mechanical thrombectomy (Stroke 2009;40:516).

Future: RCTs that emphasize rapid reperfusion w/the use of newer stent retrievers while reducing time to IAT w/prehospital & inhospital process improvement (JAHA 2014;3:e000963). Two RCTs (SWIFT PRIME & THERAPY) on hold given benefit of MRCLEAN.

Abbreviations: PROACT, Prolyse in Acute Cerebral Thromboembolism; IMS, Interventional Mgmt of Stroke; SYNTHESIS, Intra-arterial vs. Systemic Thrombolysis for Acute Ischemic Stroke; MRRESCUE, Mechanical Retrieval & Recanalization of
Stroke Clots Using Embolectomy; MRCLEAN, Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; ESCAPE, Endovascular Treatment for Small Core & Proximal Occlusion Ischemic Stroke; IA, intra-arterial; IAT, intra-arterial therapy; ICA, internal carotid artery; ACA, anterior cerebral artery; MCA, middle cerebral artery; VA, vertebral artery; BA, basilar artery; SAH, subarachnoid hemorrhage; & sICH, symptomatic intracerebral hemorrhage.

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