Cardiac and Hemodynamic Effects of Infrarenal Aortic Clamping During Repair of Abdominal Aortic Aneurysms. A Reason for Combined Coronary Bypass and Aneurysm Repair in Patients with Severe Coronary Artery Disease

Abstract

Coronary disease is the leading cause of early and late death after any type of vascular operation, but its immediate implications are more serious in patients who require abdominal aortic reconstruction. Infrarenal cross-clamping required during aortic replacement is generally well tolerated but may occasionally lead to severe hemodynamic disturbances in patients suffering from coronary artery disease (CAD).

The authors performed prospective registration of hemodynamic and cardiac effects of infrarenal aortic clamping in three groups of 25 patients each who underwent infrarenal aortic aneurysm repair. Group I included patients without CAD, group II patients had manifest signs of CAD, whereas patients in group III underwent aortic repair immediately after coronary revascularization, as part of a combined approach.

Patients with CAD demonstrated significant increase of central venous pressure, pulmonary arterial pressure, and pulmonary capillary wedge pressure after aortic clamping. Cardiac output measurements showed a significant decrease while systemic vascular resistance increased. A majority of patients presented ischemic ECG alterations and/or arrhythmia. Patients of group III presented an intermediate response to aortic clamping as compared with cardiac-healthy patients of group I and coronary patients from group II. However, there were no signs of ischemia after cross-clamping in this group of patients.

The study demonstrates clearly the different tolerances to the stress of aortic cross-clamping in patients with and without CAD. Intraoperative transesophageal echocardiography allowed the authors to detect dilatation of the cardiac cavities following cross-clamping in patients with severe CAD; when this is not available, left ventricular filling pressure should be monitored in patients with CAD undergoing abdominal aortic repair. Registration of left ventricular pressure is a prerequisite for proper intraoperative application of vasodilators.