Abstract 4908: Stunning and Cumulative LV Dysfunction Occurs after Serial Coronary Occlusion in Humans
Serial episodes of demand ischemia induced by dobutamine stress have been shown to produce cumulative stunning and LV dysfunction. Repeated episodes of worsening stunning may explain the phenomenon of hibernation. We hypothesized that a supply ischemia model of LV dysfunction in humans would also exhibit cumulative stunning and LV dysfunction. Twenty patients undergoing proximal single vessel elective PCI (17 LAD, 2 LCx and 1 RCA) to a type-A stenosis had intraventricular pressure-volume loops measured by LV conductance catheter to derive the contractility indices: dP/dt max, Tau, stroke volume (SV) and ejection fraction (EF). A Volcano® guide wire enabled simultaneous recordings of intracoronary pressure and flow velocity. Measurements were recorded at baseline (BL) and after one minute of low-pressure coronary balloon occlusion (BO). These measurements were repeated again 30 minutes later. BO1 did not significantly alter the stenosis morphology: mean (SEM) stenosis QCA (%) pre: 83.3 (11.6) vs. post: 86.7 (11.9), p=0.63 nor mean baseline coronary average peak velocities (cm/sec): BL1 15.2 (1.1) vs. BL2 15.4 (1.1), p=0.62. However, BO1 did significantly impair LV contractility indices: mean (SEM) SV (ml): 88.6 (5.2) vs. 77.3 (7.9), p=0.04 and Tau (msec): BL1 12.5 (0.5) vs. BO1 15.1 (0.6), p<0.0001. After 30 minutes the LV failed to recover to baseline and on the second 1 minute coronary occlusion (BO2) cumulative worsening of LV contractility was observed (Figure⇓). Supply ischemia induced by coronary balloon occlusion in humans can induce stunning and cumulative worsening of LV dysfunction.