Hemodynamic response to infrarenal aortic cross-clamping in patients with and without coronary artery disease

The effect of coronary artery disease (CAD) on hemodynamic response to infrarenal aortic cross-clamping was studied in 25 patients undergoing either aortofemoral bypass or abdominal aortic aneurysmectomy. Ten patients had evidence of CAD and 15 did not. Systemic, pulmonary artery (PAP), and pulmonary capillary wedge pressures (PCWP), thermodilution cardiac output, and heart rate were measured immediately before, and 2 and 5 min after infrarenal aortic cross-clamping. Heart rate decreased and arterial pressures and pulmonary and systemic vascular resistances increased in both CAD and non CAD groups after aortic clamping. Cardiac index decreased after clamping in both groups and was significantly lower in the patients with CAD. However, PCWP decreased after clamping in patients without CAD as compared to a significant increase in the patients with CAD. The significantly lower cardiac index (1.8-1.9 L/min x M2) and increased PCWP (13-15 torr) in patients with preexisting CAD scheduled for aortofemoral surgery may suggest that this subgroup is at greater risk for myocardial dysfunction immediately after aortic cross-clamping.