George Pappas

Platelet Survival in Patients with Substitute Heart Valves

Abstract To determine the relation of thromboembolism to the presence of substitute heart valves platelet studies were performed in 55 patients. Average platelet survival was normal in patients wit...

Effect of pulsatile and nonpulsatile flow during cardiopulmonary bypass on left ventricular ejection fraction early after aortocoronary bypass surgery

Abstract Although aortocoronary bypass graft has successfully relieved angina in most patients, concern has been expressed about possible deterioration or failure of improvement of left ventricular performance. With use of intraaortic balloon pumping to produce pulsatile flow during cardiopulmonary bypass, left ventricular ejection fraction and end-diastolic volume index were compared in a consecutive series of 40 men undergoing elective aortocoronary bypass, 20 of whom had pulsatile flow and 20 who had mean flow during cardiopulmonary bypass. Left ventricular ejection fraction and end-diastolic volume index were measured before and 1 to 12 days after operation using a collimated scintillation probe and indium113m. In the group receiving nonpulsatile flow the ejection fraction decreased from 52.2 ± 2.9 percent (mean ± standard error of the mean) to 38.7 ± 3.2 percent on the first postoperative day and 43.0 ± 3.4 percent on the 10th day (P

A Simple Method of Producing Pulsatile Flow During Clinical Cardiopulmonary Bypass

Abstract A method using the intraaortic balloon to produce pulsatile flow during cardiopulmonary bypass is described. The technique has been employed in 26 patients, and there have been no complications.

Effect of parent coronary arterial occlusion on left ventricular function after aortocoronary bypass surgery

In 62 men with open parent coronary arteries who underwent saphenous vein aortocoronary bypass to either the right or left anterior descending coronary artery, or both, left ventricular ejection fraction and wall motion of the anterior and inferior segments of the left ventricle were measured before and after (average 11 months) the operation. Of 34 left ventricular segments with open vein grafts and open parent coronary arteries, 91 percent were unaltered by the operation, none were in worse condition and 9 percent showed improved wall movement. Among 33 segments with open grafts but new total occlusion of the parent coronary arteries, 67 percent were unaltered, whereas the condition of 18 percent was worse and of 15 percent was improved. Among 21 segments with closed grafts but patent parent arteries, the condition of 29 percent was unchanged and of 71 percent was worse; among 14 segments with occlusion of both grafts and parent arteries the condition of 29 percent was unchanged and of 71 percent was worse. In 10 men with patency of all vein grafts and parent arteries, left ventricular ejection fraction was not altered (0.55 +/- 0.03 to 0.53 +/- 0.04 [average +/- standard error of the mean]) and in 11 with all grafts open but all parent arteries occluded left ventricular ejection fraction was unchanged (0.51 +/- 0.02 to 0.54 +/- 0.03). Left ventricular ejection fraction was decreased in eight men with occlusion of all vein grafts whether or not occlusion of the parent coronary arteries had occurred. The results suggest that occlusion of the parent coronary arteries in the presence of a patent vein graft does not unfavorably alter left ventricular ejection fraction or segmental wall motion, whereas graft occlusion is associated with deterioration of left ventricular ejection fraction and segmental motion whether or not the parent artery is also occluded.

Retrograde False Channel Perfusion: A Complication of Cardiopulmonary Bypass during Repair of Dissecting Aneurysms

The current surgical treatment of dissecting thoracic aneurysms that originate above the aortic valve and dissect distally (Type I—De Bakey [3]) requires cardiopulmonary bypass for repair of the proximal intimal tear and obliteration of the false lumen [1, 2, 4, 5]. When the dissecting process extends toward the femoral arteries, cannulation of these vessels may result in perfusion of the false lumen. In addition, although a femoral cannula is inserted into the true lumen, perfusion of the false channel may occur through large reentry sites in the distal abdominal aorta or beyond the bifurcation. Retrograde arterial flow through the false lumen would jeopardize the blood flow to the central nervous system and to other vital organs. We have observed this complication in 2 patients with complete aortic dissection (Type I) during what appeared to be an otherwise adequate surgical procedure.

Fractured intracardiac transvenous pacemaker catheter: An unusual cause of pacemaker failure

Abstract Disruption of a permanent transvenous catheter within cardiac chambers is an unusual cause of pacemaker failure. The use of open cardiotomy for removal of the fractured catheter avoids the potential complications seen in the case reported, namely dislodgement of thrombi, and tricuspid valve damage secondary to fibrous tissue fixation of the fractured transvenous pacing catheter to the tricuspid valve. Disruption of a permanent transvenous electrode catheter can occur even if the stainless steel stylet, used for positioning, has been removed.

Supported and Nonsupported Valve Homografts in Man

Abstract In terms of valvular insufficiency, there appears to be little difference between stented and unstented orthotopic aortic valve homografts. Inverted aortic valves in the mitral position, however, resulted in mitral insufficiency in 6 of 19 patients who survived operation. In 3 of the 6 patients this was due to particular technical factors. Clinical and catheterization evidence suggests that a greater degree of turbulence and obstruction occurs with stented than with unstented valves. We cannot state with confidence that the aortic homograft in the mitral position offers a real advantage over some forms of prostheses except from the standpoint of embolic complications. The use of aortic valve homografts has been successful in obviating systemic embolism when this has been a problem with prosthetic valves inserted in the mitral area. Histologically, fresh valves show greater cellularity than do frozen valves, particularly in the first 6 months. Later on, both are acellular. Whether or not this has a bearing on the ultimate performance of the valve remains to be seen. We now prefer to use fresh unstented homografts in the aortic position in the typical patient. The use of stented valves in this area seems to offer an advantage when bypass time needs to be short, however, or when there is inherent weakness or enlargement of the aortic root.

Creation of dissecting thoracic aortic aneurysms in dogs

Abstract A technique of creating dissecting thoracic aneurysms in dogs is described. Carbon dioxide under pressure was used to initiate the dissecting process, and an intimal tear was then surgically created. The mortality rate of dissections involving the ascending portion and the arch of the aorta or the entire thoracic aorta was exceedingly high. Dissections involving the descending aorta alone had a more favorable outlook. This experimental model may prove useful in the evaluation of the nature of the lesions and efficacy of various forms of treatment of this disease entity.

Early Effect of Cardiac Surgery on Left-Ventricular Ejection Fraction

Aortocoronary artery bypass (ACB) is being performed with increased frequency for the relief of angina in patients with coronary artery disease.1,2 Despite the satisfactory relief of angina, however, there has been concern that the operation may be associated with either deterioration or lack of improvement in left ventricular (LV) performance.3–6 In addition, there is a definite risk of intraoperative acute myocardial infarction. 7–8 Also, low cardiac output is frequently observed early after valve replacement surgery, and this may reflect LV dysfunction. Considerable attention has been paid to optimal preservation of myocardium in patients undergoing cardiac surgical procedures.