[Methods of evaluating myocardial revascularization surgery].

The quality of revascularization is evaluated by measurements of blood flow and various imaging methods. The quality of the anastomosis and the graft flow are evaluated per-operatively by ultrasounds and by measurements of intramyocardial pH. After surgery, Doppler velocimetry and radioisotope scanning assess the basal coronary flow and the coronary reserve. Graft patency can be studied by noninvasive methods (Doppler and kinetic CT with contrast injection), but conventional or digital angiography is irreplaceable for visualization. Residual myocardial ischaemia and left ventricular function are evaluated by the usual methods. Angina is not sensitive enough to serve as an indicator of residual or recurrent myocardial ischaemia. ECG at rest detects most peri-operative infarctions; Holter recordings may reveal a silent myocardial ischaemia; exercise stress ECG evaluates (albeit with insufficient sensitivity) post-bypass changes in myocardial ischaemia. Myocardial scintigraphy with thallium-201 is more sensitive, and it locates low perfusion areas. Cardiac wall kinetics and left ventricular function at rest and during exercise are studied by echocardiography and contrast or isotopic ventriculography, pending advances in nuclear magnetic resonance imaging. Surgical results have never been compared with other methods of direct myocardial revascularization, but only with medical treatments. Outstanding among the controlled studies carried out are a European study (E.C.S.S.) and two North American studies (V.A.S. and C.A.S.S.); they have shown what can be expected from coronary bypass, globally and in some subgroups of patients.