EFFECT OF PERIPHERAL CARDIOPULMONARY BYPASS ON LEFT-VENTRICULAR SIZE, AFTERLOAD AND MYOCARDIAL-FUNCTION DURING ELECTIVE SUPPORTED CORONARY ANGIOPLASTY

Although cardiopulmonary bypass support has been increasingly used for high risk coronary angioplasty, few data exist regarding its effects on left ventricular function. Accordingly, in 20 patients changes in left ventricular size, afterload and myocardial function where assessed by continuous hemodynamic monitoring and simultaneous two-dimensional echocardiography during cardiopulmonary bypass-supported high risk angioplasty. The cross-sectional left ventricular area during bypass support remained unchanged during diastole, whereas during systole it decreased (from 29.6 +/- 11.4 to 27.6 +/- 10.4 cm2, p < 0.05). Global left ventricular function expressed as fractional area change remained unchanged from baseline to bypass support but decreased during balloon inflation (from 0.27 +/- 0.11 to 0. 17 +/- 0.09, p < 0.001). The end-systolic meridional wall stress decreased during bypass support (from 141 +/- 75 to 110 +/- 58 x 10(3) dynes/cm2, p < 0.02). Regional myocardial function was assessed by a wall motion score (0 = normal, 1 = hypokinesia, 2 = akinesia and 3 = dyskinesia). Regions supplied by a stenotic (greater-than-or-equal-to 50% diameter) vessel deteriorated during bypass support (score from 0.9 +/- 0.8 to 1.06 +/- 0.8, p < 0.01), whereas regions supplied by a nonstenotic vessel did not. Regions supplied by the target vessel deteriorated further during balloon inflation (score from 0.7 +/- 0.6 to 1.7 +/- 0.75, p < 0.001). Thus, although left ventricular size and global function remain unchanged and afterload decreases during bypass support, myocardial dysfunction in regions supplied by a stenotic vessel may occur. Furthermore, regional and global left ventricular dysfunction still occur with angioplasty balloon inflation during cardiopulmonary bypass support.