Coronary Artery Disease

Coronary artery disease (CAD) is the progressive narrowing of the arteries supplying the heart muscle by atherosclerotic plaque — a build-up of cholesterol, inflammatory cells, and calcium inside the artery wall. This narrowing reduces blood flow to the heart, causing exertional chest pain (stable angina) or, when a plaque ruptures and triggers a clot, a heart attack. CAD is the leading cause of death in India and worldwide, and is the most common reason for coronary angiography, angioplasty, and bypass surgery.

Stable angina is predictable chest tightness on exertion that relieves at rest — caused by a fixed narrowing. Unstable angina is new or worsening rest pain from a partially ruptured plaque — a cardiological emergency. NSTEMI is a heart attack with elevated troponin but no ST elevation on ECG — partial artery blockage with muscle damage. STEMI is a complete coronary artery occlusion causing ST elevation on ECG — the most severe type requiring emergency angioplasty within 90–120 minutes.

Coronary angioplasty (PCI) is a catheter-based procedure that opens narrowed coronary arteries using a balloon and implants a drug-eluting stent to keep the artery open. No open-chest surgery is required. It is the treatment of choice for STEMI (emergency PCI within 90 minutes), high-risk ACS, and stable angina with ischaemia that is not controlled by medications. At Heartwise Cardiology, all PCI is performed via the radial artery (wrist access) with IVUS or OCT imaging guidance and FFR measurement — providing the highest quality of stent implantation and ensuring stenting is restricted to physiologically significant lesions.

Angioplasty (PCI) opens the blocked artery from inside via catheter — no chest opening, 24–48 hour discharge. Bypass surgery (CABG) creates new vessels that bypass the blocked segments — requires open-chest surgery and 5–7 day stay. CABG is preferred for complex three-vessel disease (SYNTAX score >32), left main disease with high complexity, and diabetics with multi-vessel CAD. PCI is preferred for single-vessel disease, selected two-vessel disease, and low-complexity left main disease. The decision is made jointly by the cardiologist and cardiac surgeon based on the SYNTAX score and clinical factors.

Coronary stents have evolved significantly over the past two decades. Bare-metal stents (BMS) were the first generation — effective at holding arteries open but had high rates of restenosis (re-narrowing) of 20–30%. Drug-eluting stents (DES) are coated with medications that prevent scar tissue from growing through the stent, reducing restenosis to under 5%. Modern DES use biodegradable polymers or polymer-free coatings that reduce the risk of very late stent thrombosis. Bioresorbable scaffolds were designed to dissolve completely over 2–3 years but had higher complication rates and are now rarely used. At Heartwise Cardiology, all stenting is performed with contemporary drug-eluting stents guided by IVUS or OCT imaging to ensure optimal expansion and apposition.

Coronary artery disease can be stabilised and, in some cases, modest plaque regression can be achieved with aggressive risk factor management. High-intensity statin therapy can reduce LDL cholesterol to very low levels, which halts plaque progression and can cause mild plaque regression (reduction in plaque volume by 5–10% over 1–2 years). Lifestyle changes — including smoking cessation, the Mediterranean diet, regular exercise, and weight loss — further stabilise plaques by reducing inflammation and improving endothelial function. However, advanced calcified plaques and established blockages do not fully disappear. The goal of treatment is plaque stabilisation (making plaques less likely to rupture and cause heart attacks) combined with revascularisation (stenting or bypass) for flow-limiting blockages.

After a drug-eluting stent is placed, dual antiplatelet therapy (DAPT — typically aspirin plus a P2Y12 inhibitor such as clopidogrel, ticagrelor, or prasugrel) is required to prevent stent thrombosis — a rare but catastrophic complication where a clot forms inside the stent. For patients with stable CAD, DAPT is recommended for at least 6 months, after which aspirin alone is continued lifelong. For patients who had a heart attack (NSTEMI or STEMI), DAPT is needed for at least 12 months. Patients at high bleeding risk (elderly, kidney disease, history of bleeding) may require shorter DAPT durations. After 12 months, most patients continue single antiplatelet therapy (aspirin or clopidogrel) lifelong.

CT coronary angiography (CTCA) is a non-invasive scan that uses a CT scanner with contrast dye to visualise the coronary arteries. It takes about 15 minutes, can be done as an outpatient, and requires only an IV line in the arm. CTCA is excellent for ruling out coronary artery disease — a normal scan has a negative predictive value of over 95%. It can identify plaque and estimate stenosis severity but cannot treat blockages. Traditional invasive coronary angiography is a catheter procedure where a thin tube is inserted via the wrist (radial artery) and contrast is injected directly into the coronary arteries. It is slightly more accurate for severe stenoses, allows FFR measurement to assess physiological significance of blockages, and can be immediately followed by angioplasty and stenting if needed. CTCA is typically used first for low-to-intermediate risk patients; invasive angiography is reserved for high-risk patients or those with positive non-invasive tests.