percutaneous coronary intervention

**Definition & technique:** Access is via radial (preferred, lower bleeding and mortality) or femoral artery. A guide catheter is advanced to the coronary ostium, a wire crosses the lesion, and a balloon is inflated to compress the atheromatous plaque (balloon angioplasty). A stent (metal scaffold) is then deployed. Intravascular imaging (IVUS/OCT) and physiologic assessment (FFR, iFR) can guide decisions. Intraprocedural anticoagulation is with unfractionated heparin or bivalirudin.

**Indications:** - **STEMI:** Primary PCI is preferred over fibrinolysis if it can be done within 90 min of first medical contact (door-to-balloon ≤90 min; if transfer is needed, ≤120 min from first contact, otherwise give fibrinolytics within 30 min door-to-needle). - **NSTEMI/unstable angina:** Early invasive strategy (within 24 h) for high-risk features: hemodynamic or electrical instability, refractory angina, elevated GRACE score. Immediate (<2 h) for very high-risk patients. - **Stable ischemic heart disease:** Only for symptoms refractory to guideline-directed medical therapy, or for left main/multivessel disease in selected patients. In stable CAD, PCI improves symptoms but does NOT reduce death or MI over optimal medical therapy (COURAGE, ISCHEMIA trials). - **CABG favored over PCI:** Left main disease, three-vessel disease (especially with diabetes, as in FREEDOM), and low EF (SYNTAX score guides this decision).

**Stent types:** - **Bare-metal stent (BMS):** Higher rate of in-stent restenosis (neointimal hyperplasia) from smooth muscle proliferation. DAPT is needed for a shorter time (~1 month). - **Drug-eluting stent (DES):** Elutes antiproliferative drugs (sirolimus, everolimus, paclitaxel) that reduce restenosis. This is the standard of care. DAPT is typically 6–12 months (ACS: 12 months; stable CAD: ~6 months), and shorter durations are acceptable in high bleeding risk.

**Adjunctive pharmacotherapy:** Aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor). Prasugrel and ticagrelor are preferred in ACS. Prasugrel is contraindicated with prior stroke/TIA and is generally avoided in patients ≥75 years or <60 kg. Ticagrelor causes dyspnea. Clopidogrel is a prodrug activated by CYP2C19 (poor metabolizers have reduced efficacy; avoid omeprazole). GP IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban) are used selectively as bailout therapy.

**Complications:** - **Acute stent thrombosis** (within 24 h) and **subacute** (within 30 days): often from premature DAPT discontinuation. Presents as recurrent STEMI. - **In-stent restenosis:** Typically months after BMS placement. Presents with recurrent angina. - **Coronary artery dissection/perforation** with tamponade. - **Access site complications:** Hematoma, retroperitoneal bleed (femoral access; presents with flank/back pain and hypotension), pseudoaneurysm, AV fistula. - **Contrast-induced nephropathy:** Prevent with hydration; hold metformin and NSAIDs as appropriate. - **No-reflow phenomenon**, arrhythmias (reperfusion arrhythmias, e.g., accelerated idioventricular rhythm), allergic reaction to contrast, and atheroembolism. - **Periprocedural MI** and stroke.

**Clinical pearls for boards:** - Reperfusion after STEMI: PCI is superior to fibrinolysis when timely. Fibrinolytics are indicated if PCI is delayed (>120 min), with contraindications such as prior intracranial hemorrhage, recent stroke, active bleeding, or suspected aortic dissection. - Cardiogenic shock complicating MI: emergent revascularization (PCI or CABG) is indicated (SHOCK trial). - Culprit-only PCI is generally favored in STEMI with shock, while complete revascularization of non-culprit lesions benefits stable STEMI patients. - Patients needing DAPT who also require oral anticoagulation (e.g., AF) generally receive a DOAC plus a P2Y12 inhibitor (clopidogrel) and drop aspirin early to limit bleeding. - Elective noncardiac surgery should be delayed until DAPT is complete if possible (ideally ≥6 months after DES for stable CAD, ≥12 months after ACS) because of stent thrombosis risk. - Post-PCI care: high-intensity statin, beta-blocker (especially post-MI/low EF), ACE inhibitor/ARB (EF ≤40%, diabetes, HTN, CKD), cardiac rehab, risk factor modification.