The left anterior descending artery (LAD) is the most important coronary artery, arising from the left main coronary artery and descending in the anterior interventricular groove to the cardiac apex. It gives rise to diagonal branches supplying the anterior left ventricular wall and septal perforators supplying the interventricular septum and the anterior fascicle of the left bundle branch. It typically wraps around the apex to supply a portion of the posterior left ventricular wall.
LAD occlusion causes the largest myocardial infarction territory, historically called the widow-maker infarct when the proximal LAD is occluded before the first diagonal, producing anterior ST elevation MI with global anterior and septal wall motion loss. Atherosclerotic LAD disease is the most common target for surgical revascularisation, with the left internal thoracic artery (LIMA) to LAD anastomosis the gold standard coronary bypass with 10-year patency exceeding 90%. LAD stenosis causing stable angina is managed by percutaneous coronary intervention with drug-eluting stent placement.
Acute thrombotic occlusion of the proximal LAD (widow-maker) produces anterior ST elevation MI with broad anterior, septal, and apical wall motion loss, cardiogenic shock risk, and the highest mortality of any STEMI territory, requiring immediate primary PCI with thrombectomy and stenting.
Non-atherosclerotic dissection of the LAD wall, occurring predominantly in young women in the peripartum period or with fibromuscular dysplasia, produces acute MI managed conservatively in haemodynamically stable patients or with PCI when flow is severely compromised.
