[Angiographically unexplained myocardial ischemia in high grade coronary stenosis with main stem involvement in...

For seven weeks a 57-year-old man had been complaining of recurrent non-radiating retrosternal pain and pressure on slightest exertion. Admission physical examination was unremarkable except for evidence of peripheral vascular disease. Cardiovascular risk factors were hypertension, hyperlipoproteinaemia and obesity.

The resting ECG was unremarkable. Objective signs of myocardial ischaemia were produced in the exercise ECG (angina at 100 Watt, negative T waves in V2 to V6 and borderline S-T depression in V4). Myocardial scintigraphy showed reversible reduced perfusion of the anterior wall near the apex and also of the apex and septum. Left ventricular (LV) angiography demonstrated a normally contracting LV, while selective coronary angiogram revealed a 20% reduction in caliber of the proximal branch of the anterior interventricular branch (AIVB), with otherwise normal coronary arteries. Subsequent intravascular ultrasound (IVUS) showed a circular echo-poor 80% stenosis at the origin of the AIVB with extension to the main stem.

A bypass from the internal mammary artery to the AIVB and an aortocoronary venous bypass to the intermediate branch were performed. The patient was free of symptoms postoperatively.

If cases where there is a discrepancy between clinical and coronary angiographic findings--the latter being unclear or inconsistent, especially in the area of the left main stem, bifurcations or vessel origin--IVUS may contribute decisively to demonstrating coronary anatomy or pathology, and to indicating the type of revascularizing measures.