In situ preservation of cadaver kidneys for transplantation: laboratory observations and clinical application

Many kidneys obtained from cadaver donors undergoing sudden cardiac arrest cannot be transplanted due to the long periods of warm ischemia from the moment of arrest to nephrectomy. A double-ballon-triple-lumen catheter for the rapid in situ preservation of cadaver kidneys has been designed. Used in combination with equipment routinely found in any hospital, it can cool human kidneys in situ to 10-15 C and maintain this temperature until nephrectomy can be performed. Kidenys preserved with this catheter have functioned after transplantation into suitable recipients. This report describes the design and laboratory evaluation of this new device, its clinical effectiveness and technique of insertion.

Localization of apo-lipoproteins in human carotid artery plaques

Apoproteins from plasma lipoproteins were localized by immunofluorescence techniques in human carotid artery atherosclerotic lesions. These studies were performed in light of the possible importance of these apoproteins in both lipid metabolism and the pathogenesis of atherosclerosis. ApoA-I from high density lipoproteins, apoB from low density lipoproteins, and apoC-III from very low density lipoproteins were localized also as markers for their respective lipoproteins, since the latter cross-react immunologically. The three apoproteins were localized to the same regions of lesions as neutral lipids and, to some extent, fibrinogen. These regions consisted of bands of collagen fibers, usually deeper within the lesion, and the lipid core or atheroma of such advanced lesions. Although the superposition of localization for the three apoproteins and lipid was only 53%, it was suggested that deviation from complete superposition was due to the abrupt changes in lesion structure resulting from the focal nature of the atherosclerotic process. These results suggest that there is a broader specificity than previously implied of the interaction between such lesion components as connective tissue and extracellular lipid accumulations, and apoproteins from plasma lipoproteins. This interaction is believed to result in a net retention within atherosclerotic lesions of human extracranial arteries of these plasma-derived factors, either as free apoproteins or as native lipoproteins.

Ascending aortic aneurysms. Review of 100 consecutive cases

Aneurysms of the ascending aorta, if undiagnosed or untreated, may result in left ventricular failure from aortic valvular insufficiency. Aortic rupture, dissection, or compression of adjacent vital structures may also occur. The application of refined cardiopulmonary bypass devices, prosthetic heart valves, and synthetic grafts now allows successful surgical management of this disorder. This report presents our current diagnostic methods, surgical techniques, and the early and late results of 100 consecutive patients undergoing surgical treatment of aneurysms of the ascending aorta. There were 72 males and 28 females, ranging in age from 25 to 72 (ave 51.2) years. All patients had angiographic studies to demonstrate precisely the location of the aneurysm and the presence or absence of aortic valvular insufficiency. Sixty-three patients required concomitant aortic valve replacement, and the remaining 37 patients had only aneurysm resection and replacement. Pathological studies revealed 69 aneurysms were atherosclerotic, 22 were secondary to cystic medial necrosis, with the remaining 9 considered to be possibly leutic in origin. Despite the magnitude of the surgery and the advanced ages of some of these patients, the overall operative and hospital mortality rates were 4% and 9%. Survival rates by actuarial representation in 82 patients at 2, 4, 6, and 8 years were 82.9%, 78%, 70%, and 69.5%, respectively.

Cardiopulmonary bypass. Microembolization and platelet aggregation

Particulate microemboli and in vitro platelet aggregation were studied in blood of patients during cardiac operations with an electronic particle size analyzer. A small gradient of microemboli developed on passage of blood through a bubble oxygenator but not through a membrane oxygenator. However, with both types of oxygenators, there was a sustained increase in the volume of microemboli in cardiotomy return blood which was much greater than in aterial blood. After cardiopulmonary bypass with both oxygenators, there was a comparable reduction in the volume of circulating platelets which exceeded that of the hemoglobin concentration, indicating platelet loss exceeded that that expected from hemodilution alone. However, the total volume and mean size of platelet aggregates induced in blood of patients after membrane oxygenation was significantly greater than similar measurements after bubble oxygenation. This study shows that membrane oxygenation reduces particulate microembolization and preserves platelet function in patients undergoing cardiac operations when compared to bubble oxygenation.

Platelet aggregation: effects of cardiopulmonary bypass

This study was designed to determine whether reduction in platelet aggregate microembolization during the first 30 minutes of cardiopulmonary bypass is due to thrombocytopenia or to decreased ability of platelets to aggregate. The total volume of platelet aggregates induced in blood by adenosine diphosphate (ADP) was measured with a Coulter counter. The volume of platelets in blood was calculated by multiplying hemocytometry platelet counts by the mean platelet volume. Immediately before cardiopulmonary bypass, the total volume of aggregates induced in blood by ADP (2muM) was reduced when compared to normal donors because of (1) a slight fall in the volume of platelets, and (2) reduction in the percentage by volume of platelets which aggregated. After 30 minutes on bypass, the volume of both platelets and aggregates fell, but a greater percentage of platelets aggregated. This indicates that reduction of platelet aggregate formation during cardiopulmonary bypass is due to thrombocytopenia. It also suggests that anesthesia, surgical trauma and heparinization alter platelet reactivity more than cardiopulmonary bypass.