Makindo Medical Notes

Related Subjects: |Atherosclerosis |Ischaemic heart disease |Assessing Chest Pain |ACS - General |ACS - STEMI |ACS - NSTEMI |ACS - GRACE Score |ACS - ECG Changes |ACS -Cardiac Troponins |ACS - Post MI arrhythmias |ACS: Right Ventricular Infarction

Consult closely with a cardiologist before discontinuing antiplatelet therapy soon after stent placement. Patients with drug-eluting stents have a higher risk of in-stent thrombosis if antiplatelet agents are stopped prematurely. Typically, clopidogrel is continued for about one year, though guidelines may vary. Always confirm current recommendations with a cardiology team.

About

• Acute Coronary Interventions: Percutaneous Coronary Intervention (PCI) is performed to alleviate angina and improve coronary blood flow. While elective PCI does not significantly reduce mortality, it can alleviate symptoms and improve quality of life.
• Coronary angiography and PCI have evolved from solely identifying candidates for CABG to offering increasingly complex, less invasive interventions.
• Widespread availability of catheterization labs, including in district hospitals, allows for complex interventions with reduced need for urgent cardiac surgery.

Stents

• Stents are metallic scaffolds placed to keep a coronary artery open after balloon angioplasty. They can be coated with antiproliferative drugs (drug-eluting stents) to reduce restenosis.
• Guidewires are advanced from a peripheral artery (radial or femoral) into the coronary artery under fluoroscopic guidance. After crossing the stenosis, the lesion is dilated with a balloon and a stent deployed.
• Drug-Eluting Stents (DES): Contain agents like sirolimus or paclitaxel to reduce neointimal hyperplasia. These are preferred in diabetics and patients with long, calcified lesions.
• Difficult lesions are complex, long, eccentric, calcified, located on vessel bends or in tortuous vessels, or involve branch points or thrombus.
• Most patients receive dual antiplatelet therapy (DAPT) for 6–12 months post-stent placement, with aspirin often continued for life.

Indications (Mortality Benefits)

• STEMI in patients who cannot receive thrombolysis.
• STEMI with hemodynamic compromise.
• STEMI if PCI can be performed within 90 minutes of first medical contact.

Other Indications

• High-risk NSTEMI.
• Unstable angina with high-risk features on stress testing.
• Unexplained ischemic cardiomyopathy.
• Cardiac arrest survivors to identify and treat causative coronary lesions.
• Significant ventricular arrhythmias (e.g., VT) due to ischemic substrates.

Vascular Access

• Common approaches: Femoral, Brachial, or Radial arteries.

Protocol

• Written informed consent is required. Baseline mortality risk from diagnostic angiography alone is about 1/1000, increasing with complexity.
• Complications include bleeding, infection, vascular damage, and rarely stroke.
• Check and document peripheral pulses (especially femoral, popliteal, dorsal pedis, and posterior tibial), FBC, platelets, U&Es, and glucose.
• Acetylcysteine may be given to protect renal function if there is a risk of contrast-induced nephropathy (consult local protocols).
• Patients typically fast for at least 6 hours. Some may receive anxiolytics. Aspirin and/or clopidogrel may be given pre-procedure.

Interventions

• Balloon Angioplasty: Balloon inflation widens the narrowed artery. However, arterial dissection and acute closure can occur, and intimal hyperplasia frequently leads to restenosis. Rarely used alone except for very small vessels.
• Bare Metal Stents (BMS): Reduce restenosis compared to balloon angioplasty alone. They are thrombogenic and require dual antiplatelet therapy for a recommended period, then lifelong aspirin.
• Drug-Eluting Stents (DES): Release antiproliferative drugs (e.g., sirolimus, paclitaxel) to reduce neointimal hyperplasia and restenosis. Require prolonged dual antiplatelet therapy (at least one year) and then lifelong aspirin.
• Referral for CABG: Consider if there is triple-vessel disease or significant left main stem involvement.

Post-Procedure Complications

• Bleeding at the access site: Apply pressure and adjust anticoagulation as needed.
• Retroperitoneal Bleeding: Suspect if patient becomes hypotensive and tachycardic without obvious external bleeding. Consider transfusion, imaging (CT abdomen), and discuss with cardiology/hematology teams.
• Acute Limb Ischemia (Cold, White Leg): May be due to thrombosis, embolism, or dissection. Urgent vascular surgery assessment and repeat angiography may be necessary.
• Vascular Complications: Pseudoaneurysm or arteriovenous fistula formation. Diagnose by ultrasound and involve vascular specialists.
• Bleeding into the Thigh: Apply pressure, adjust anticoagulation, and consider transfusion if needed.
• Acute Stent Thrombosis or In-Stent Restenosis: May present like a STEMI. Inform cardiology immediately. Repeat angiography may be required.
• Contrast-Induced Renal Failure: Monitor creatinine, ensure adequate hydration, and follow local protocols.
• Stroke: Involve the stroke team urgently if neurological deficits appear.