North American experience with the Perma-Flow prosthetic coronary graft.

BACKGROUND: The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives. METHODS: Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study. RESULTS: Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 +/- 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft. CONCLUSIONS: The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.

Deep hypothermic arrest and left thoracotomy for repair of difficult thoracic aneurysms.

Seven patients with complex thoracic aortic aneurysms were operated on using profound hypothermia and circulatory arrest through a left thoracotomy. Three patients had false aneurysms, 2 had large aneurysms precluding access for proximal control, 1 patient had had previous hemiarch replacement, and 1 patient had a thoracoabdominal aneurysm. All patients were cooled on partial cardiopulmonary bypass until the electroencephalogram was isoelectric (approximately 15 degrees C rectal temperature). Circulatory arrest times ranged from 7 to 56 minutes (median, 34 minutes). There was one death due to cardiac failure, and paraplegia developed in 1 patient. The 6 survivors are otherwise well at a median of 12 months postoperatively. Hypothermia and circulatory arrest is an invaluable technique for the treatment of complex aortic aneurysms requiring left thoracotomy for resection. The techniques employed are described and the indications for their use are discussed.

Pericardial fluid gas analysis in hemorrhagic pericardial tamponade.

Nine patients with hemorrhagic pericardial tamponade were studied to determine the localizing value of gas analysis of pericardial fluid in therapeutic pericardiocentesis. The aspirate and the central venous blood was analyzed simultaneously for partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), and hematocrit at the time of pericardiocentesis. In all 9 patients the difference in hematocrit between the pericardial fluid and the central venous blood was not significant. The PCO2 of pericardial fluid was significantly higher than that of central venous blood (p less than 0.025). The PO2 of pericardial fluid was consistently and significantly lower than that of central venous blood (p less than 0.005). We conclude that in patients with hemorrhagic pericardial tamponade, the simultaneous measurement of PO2 and PCO2 of central venous blood and pericardial fluid is a useful rapid bedside method to confirm the site of aspiration during pericardiocentesis. The PO2 determination is statistically the best discriminator between the two fluids in this setting.