Faculty Bibliography

The outcome of patients undergoing coronary artery bypass grafting with preoperative ejection fractions below 40% was evaluated to determine if a specific level of ventricular dysfunction resulted in unacceptably poor short-term or long-term survival rates. Left ventricular ejection fractions were segregated into groups of five percentage points each starting from 35% to 39% and progressing down to 10% to 14%. In evaluating the six ejection fraction groups between 10% and 39%, we found no significant differences among them with regard to previous myocardial infarctions, left ventricular end-diastolic pressure (LVEDP), age, preoperative New York Heart Association (NYHA) class, or number of vessels bypassed. Eighty-four percent were men and 16% women. From 1976 through 1982, 466 patients were distributed among these groups, all having ejection fractions below 40% (mean 30% +/- 3% SEM). There were significant differences (p = 0.001) in both the hospital and long-term survival (36 months) of patients with preoperative ejection fractions from 20% to 39% (425 patients) as compared to those with preoperative ejection fractions from 10% to 19% (41 patients). Hospital survival rate was 89% for patients with ejection fractions from 20% to 39% but only 63% for patients with ejection fractions below 20%. Similarly, at 3 years, patients with ejection fractions of 20% to 39% had an average survival rate of 60% as compared to an average survival rate of 15% for those with ejection fractions below 20%. Neither the preoperative LVEDP nor the intraoperative ischemic arrest time significantly predicted survival. In all survivors, NYHA class decreased from an average of 3.00 to 1.25 in surviving patients following bypass at a mean follow-up of 29 +/- 5 months. It is concluded that ejection fraction is an excellent predictor of short-term and long-term survival following coronary artery bypass grafting. Patients with ejection fractions of 10% to 19% have a significantly reduced short-term and long-term survival rate as compared to patients with ejection fractions of 20% or more

Increasing longevity makes the consideration of coronary bypass common in elderly patients. Seventy-five patients 70 years of age or older undergoing coronary artery bypass grafting (CABG) for angina pectoris were compared to a control group of 75 patients under 70 years of age. The groups were matched for male:female ratio (46:29), previous infarction (28/75), unstable angina (27/75), and the requirement for preoperative intra-aortic balloon pumping (7/75). Patients under 70 years of age had an average preoperative New York Heart Association (NYHA) class of 3.0 +/- 0.6 (SEM) and an average left ventricular end-diastolic pressure of 15.5 +/- 0.8 mm Hg, compared to 3.3 +/- 0.6 and 12.9 +/- 1.1 mm Hg, respectively, for the older group. Average grafts per patient were 2.7 +/- 0.8 in the younger group and 2.8 +/- 0.1 in the older group. Overall operative mortality for patients under 70 was 4% (3/75) versus 12% (9/75) (p = 0.06) for patients 70 and older. The incidence of chronic stable angina was 2% (1/48) versus 6% (3/48) (p = 0.30). Perioperative infarctions occurred in 7% of those under 70 and 5% of those 70 or older (p = 0.54). Those under 70 averaged 13.8 +/- 0.6 postoperative hospital days versus 18.4 +/- 1.2 hospital days for the older group (p less than 0.05). Follow-up ranged from 2 to 94 months, averaging 22 months for patients under 70 and 24 months for those 70 or older. Late cardiac mortality rates were 4% (3/70) in the younger patients and 3% (2/66) in the older patients (p = 0.53). Current NYHA class was 1.3 +/- 0.7 for those under 70, with 9% reporting angina, and 1.4 +/- 0.7 for those who were 70 or older, with 6% reporting angina. CABG can be performed with acceptable risk in older patients and leads to encouraging symptomatic improvement and late survival

The theoretical concept of delivering oxygenated blood to an ischemic myocardium by way of the coronary venous system antedated by many decades the present widespread utilization of coronary artery bypass grafting. Diffuse arterial atherosclerosis has limited the effectiveness of coronary artery bypass grafting in about 15% of patients seen with significant angina pectoris. Consequently, there has been renewed interest in selectively reversing the flow in certain coronary veins through coronary venous bypass grafts. This collective review details the physiology and anatomy of the coronary venous system. It then discusses the early attempts to globally retroperfuse the entire coronary venous system through the coronary sinus. Finally, the current experimental and clinical attempts to selectively retroperfuse just one region of the coronary venous system are presented and reviewed

The long-term effectiveness of a retrograde coronary venous bypass graft (CVBG) to an ischemic left ventricle was evaluated in 18 dogs. A saphenous vein was interposed between the aorta and left anterior descending (LAD) vein. The LAD vein was ligated cephalad to the CVBG to prevent an arteriovenous fistula. The LAD artery was ligated at its origin to create anterior wall ischemia. Operative graft flow averaged 53 ml. per minute. The 14 surviving dogs were catheterized 3 to 5 months later. Ten of the 14 CVBG's were patent angiographically. The chests were opened and graft flow now averaged 50 ml. per minute. 141Ce microspheres were injected into the left atrium to measure myocardial flow to the anterior wall. In the 10 dogs with patent grafts, transmural flow was 39 +/- 1 (S.E.M.) ml. per 100 Gm. of tissue per minute. The endocardial/epicardial flow ratio was 1.4/1, indicating that retrograde venous perfusion effectively delivered blood to the subendocardium. After ligation of the CVBG, microsphere measured flow dropped to 15 +/- 1 ml. per 100 Gm. per minute. In 15 control dogs, anterior wall flow was 100 +/- 3 ml. per 100 Gm. per minute, decreasing to 13 +/- 2 ml. 45 minutes after ligation of the LAD artery and vein. None of the eight control dogs with simple ligation of the LAD artery and vein survived more than 5 days. Histologic examination of the anterior wall of the left ventricle, the area served by the CVBG's for 3 to 5 months, disclosed no evidence of venous sclerosis or thrombosis and no evidence of interstitial edema or hemorrhage. Thus a CVBG permitted long-term survival in an otherwise nonviable anatomic preparation. Moreover, restoration of flow with a CVBG was effective because it perfused all layers of the myocardium, especially the subendocardium--the crucial layer of myocardial muscle

Pericardial tamponade occurring late in the hospitalization of a patient who has undergone a heart operation can be life threatening. Recognition of this insidious, but treatable, complication is difficult. Three patients experienced delayed tamponade while receiving warfarin prophylactically following coronary arter bypass. Two-dimensional echocardiography was useful in recognizing the effusion (and thus aided the diagnosis of tamponade) in each patients. The question of whether prophylactic antiocagulatin should be employed for patients undergoing coronary artery bypass procedures is also considered in light of both the present experience and collected reports from the literature

Seventy-three patients aged 60 and over and 277 patients under 60 years of age underwent isolated aortic valve replacement (AVR) for aortic stenosis, regurgitation, and mixed disease from 1966 through 1975. Cardiac catheterization was performed five to nine months following operation in 77% of these patients. Follow-up averaged 55 months per patient. The hospital mortality in the elderly group was 2.7%, compared to 5.8% in the younger group. The late cardiac mortality was 21% and 19%, respectively. There was significant improvement (P less than .001) in the left ventricular end-diastolic pressure, cardiac index, and functional class in each of the three disease groups in the younger as well as the elderly patients. More important, the magnitude of improvement in each of these variables in patients over and under 60 years of age was not significantly different. Increasing longevity will make cardiac operations more common in the older population. These findings indicate that AVR carries the same low risk and brings about a similar improvement in left ventricular pump function in patients older and younger than 60