Thrombolysis & Thrombectomy - Clot Combat Intro
- Thrombolysis: Pharmacological dissolution of intravascular clots using drugs (e.g., alteplase, tenecteplase).
- Thrombectomy: Catheter-based mechanical removal of thrombus/embolus from a blood vessel.
- Goal: Rapidly restore vessel patency, prevent irreversible tissue damage, and improve patient outcomes.
- Key Indications:
- Acute Ischemic Stroke (AIS)
- Pulmonary Embolism (PE) - massive/submassive
- Deep Vein Thrombosis (DVT) - extensive iliofemoral
- Acute Limb Ischemia (ALI)
⭐ In Acute Ischemic Stroke (AIS), IV thrombolysis is typically indicated within 4.5 hours from symptom onset. Mechanical thrombectomy can be considered up to 24 hours in select large vessel occlusion patients.
Thrombolytic Agents - Lytic Arsenal Unleashed
Thrombolytics dissolve clots by activating plasminogen to plasmin, which degrades fibrin. 📌 Mnemonic: "All Ten Raccoons Steal Underwear" (Alteplase, Tenecteplase, Reteplase, Streptokinase, Urokinase).
| Agent | Mechanism | Half-life (min) | Key Uses |
|---|---|---|---|
| Alteplase (tPA) | Fibrin-specific; direct plasminogen activation | 4-6 | MI, PE, Ischemic Stroke (3-4.5h window) |
| Reteplase (rPA) | Fibrin-specific; longer-acting tPA mutant | 13-16 | Acute MI |
| Tenecteplase | ↑ Fibrin-specific; tPA mutant, single bolus | 20-24 | Acute MI |
| Streptokinase | Plasminogen complex formation; antigenic | 18-25 | MI, PE, DVT; ⚠️Allergy risk |
| Urokinase | Direct plasminogen activation | 10-20 | PE, DVT, Peripheral Arterial Occlusion (PAO) |
- Catheter-Directed Thrombolysis (CDT): Delivers drug directly to clot via catheter, ↑ local concentration, ↓ systemic effects. Standard tPA dose for PE: 100mg over 2h. For stroke: 0.9mg/kg (max 90mg), 10% bolus, rest over 1h.
Thrombectomy Techniques - Mechanical Mavericks
- Device-based clot removal for rapid revascularization in LVO stroke, DVT, PE. Goal: Restore flow, minimize tissue damage.
| Device | Principle | Primary Use | Example/Note |
|---|---|---|---|
| Aspiration | Suction via catheter | Stroke (LVO), PE, DVT | Penumbra |
| Rheolytic | Saline jets (Venturi effect), macerates clot | DVT, PE, Arterial occlusion | AngioJet |
| Stent Retrievers | Mesh stent traps & retrieves clot | Stroke (LVO) - standard! | Solitaire, Trevo |
| Fragmentation | Rotating wire/balloon breaks clot | DVT, PE | Often with lytics |
⭐ MT is standard for LVO stroke up to 24 hrs in select patients (DAWN/DEFUSE-3 trials).
Contraindications & Complications - Caution & Care
Thrombolysis Contraindications: 📌 HIS TUB (Absolute):
- Head trauma/stroke (<3mo)
- ICH (prior)
- Surgery (IC/spinal <3mo); Severe HTN (>185/110 mmHg)
- Thrombocytopenia (<100,000/µL)
- Use of anticoagulants (INR >1.7)
- Bleeding (active/diathesis); Aortic dissection (suspected)
| Absolute Highlights | Relative Considerations |
|---|---|
| Active bleed; Prior ICH | Recent major surgery/trauma (<10d, non-head) |
| IC Neoplasm/AVM/aneurysm; IC/spinal surg <3mo | Prolonged CPR (>10min); Recent GI/GU bleed |
| Head trauma <3mo; BP >185/110 mmHg | Noncompressible puncture; Pregnancy |
| INR >1.7; Platelets <100k/µL | Active PUD; Manageable HTN/anticoagulation |
- Hemorrhage: ICH (most feared!), access site, GI.
- Distal embolization, Reocclusion.
- Allergic reaction, CIN.
⭐ Intracranial hemorrhage (ICH) is the most feared complication of thrombolytic therapy.
Managing Post-Thrombolysis ICH:
Care: Strict BP control (post-proc <180/105 mmHg), neuro checks, coagulation monitoring.
High‑Yield Points - ⚡ Biggest Takeaways
- Thrombolysis uses drugs (e.g., tPA) or catheter-directed methods to dissolve clots in arterial/venous occlusions.
- Mechanical thrombectomy physically removes thrombus, crucial for large vessel occlusions (LVO), especially in stroke.
- Indications: Acute limb ischemia, DVT/PE, ischemic stroke (within window).
- Lytic contraindications: Active bleeding, recent major surgery, intracranial hemorrhage history.
- Major risks: Hemorrhage (intracranial), distal embolization, vessel injury.
- DSA guides intervention; CTA/MRA for diagnosis and selection.
Continue reading on Oncourse
Sign up for free to access the full lesson, plus unlimited questions, flashcards, AI-powered notes, and more.
CONTINUE READING — FREEor get the app
