Surgical Treatment for Aneurysms of the Descending Aorta Using Temporary Perfusion by a Centrifugal Pump: Clinical Analysis of 33 Cases

Abstract

Since 1987, 33 patients have undergone surgery at Kobe University Hospital for aneurysm of the descending aorta using left heart bypass with a heparin‐coated centrifugal pump and heparin‐coated tubes. Sixteen patients had true aneurysms of the descending thoracic aorta, 7 had thoracoabdominal aneurysms, and 10 had aortic dissection (DeBakey's Type III). Heat exchangers and oxygenators were not included in the bypass circuit in any of the cases. Perfusion time was from 42 to 205 min (average 90 min). Left heart bypass was established with 1 mg/kg of systemic heparinization in 5 cases, 0.5 mg/kg in 5 cases, and 0 mg/kg in 23 cases. There were no complications such as perioperative embolism, acidosis, or hypothermia. During aortic cross‐clamping, the arterial pressure of the lower extremity was maintained above 70 mm Hg, but there was no relationship between the distal perfusion pressure and bypass flow. The urine output during left heart bypass was related to the distal perfusion flow by centrifugal pump. Of 23 patients who underwent bypass with less than 40 ml/kg/min of distal perfusion flow, 7 showed transient renal dysfunction post‐operatively, and 1 developed postoperative renal failure. The other patients who were bypassed with over 40 ml/kg/min of pump flow stayed in the normal range of renal function. Postoperative paresis occurred in 2 patients, who were also perfused with less than 40 ml&kg/min of bypass flow. It could be concluded that left heart bypass by centrifugal pump is safe and acceptable as a circulatory support in the surgical treatment of aneurysm of the descending aorta. In addition, during such assistance, more than 40 ml/kg/min of perfusion flow is recommended to maintain the distal circulation and to prevent ischemic renal damage and spinal cord injury.