Hemodynamics and prostacyclin release in the early phases of aortic surgery: comparison of transabdominal and retroperitoneal approaches

Abstract

Although the retroperitoneal aortic approach (RP) is advocated to reduce myocardial ischemia and cardiac-related death, inadequate physiologic data exist to support this contention. As the aorta is exposed via the transabdominal approach (TA) we noted some patients have manifested reduced systemic vascular resistance (SVR) associated with tachycardia, reduced blood pressure, and facial flushing. To determine whether RP offered physiologic advantages over TA we compared cardiac dynamics and blood levels of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), the stable metabolite of prostacyclin, during exposure of the aorta in 52 patients (33 with TA and 19 with RP), comparable in age, cardiac history, medications, and body surface area. Serial measurements of mean arterial pressure, heart rate, wedge pressure, pulmonary artery pressure, cardiac index, and 6-keto-PGF1 alpha were obtained. Results revealed decreased mean arterial pressure and systemic vascular resistance, increased cardiac index and heart rate, and facial flush occurring 10 minutes after the bowel was explored in TA. This was not observed in RP. These hemodynamic alterations correlated in time and magnitude with a fourteen fold increase in 6-keto-PGF1 alpha. These changes in cardiac indexes can produce increased myocardial oxygen consumption with the risk for myocardial ischemia, particularly in patients with coronary artery disease. The absence of this response to bowel exploration in RP may account for some of the observed advantages in "high-risk" aortic reconstruction.