Deterioration of Myocardial Function Following Aorto-Coronary Bypass Operation

Abstract

Twenty-two patients underwent cardiac catheterization before and an average of five months after aorto-coronary bypass operation (ACBO). Two groups were examined: 10 patients with all grafts patent, and 12 patients with one or more grafts occluded. All patients improved symptomatically, regardless of graft patency. However, in the occluded group, left ventricular end-diastolic pressure (LVEDP) increased (4.4 ± 2.2 mm Hg, P < 0.05), stroke volume index fell (9.8 ± 3.1 ml/m ² , P < 0.05), ejection fraction decreased (10 ± 4%, P < 0.05), and left ventricular stroke work index fell (12 ± 3 g-m/m ² , P < 0.01). Qualitative analysis of segmental left ventricular contractility was performed. Of 28 segments supplied by patent grafts, six improved and nine deteriorated. Of 22 segments supplied by occluded grafts, none improved and eight deteriorated. Frequently no angiographically demonstrable basis for the segmental deterioration was evident. We concluded that while ACBO may appreciably benefit severely symptomatic patients, our results do not substantiate the claim that ACBO should be recommended when the primary surgical goal is preservation or enhancement of myocardial function.