William W. Angell

Ischemic myocardial injury during coronary artery surgery

Abstract ECGs and serum levels of SGOT, LDH, and CPK were examined during the postoperative period in 50 patients with angina pectoris who had myocardial revascularization procedures. ECG signs of acute myocardial infarction appeared in 34 per cent and changes compatible with acute ischemic injury were seen in 10 per cent. Elevation of SGOT exceeding 90 units occurred in 32 per cent of 50 patients, and LDH levels over 900 units occurred in 24 per cent. In patients with ECG evidence of post-operative infarction or ischemia, 50 per cent had abnormal SGOT levels and 55 per cent had abnormal LDH levels. In 16 patients with SGOT levels exceeding 90 units, 69 per cent had ECG evidence of acute infarction or ischemia. Two patients died following surgery and acute myocardial infarction was demonstrated in both at autopsy. Relief of angina occurred in one patient who developed a myocardial infarct following internal mammary implantation. A follow-up angiogram revealed no effective communication of the implant with myocardial vessels. Acute myocardial infarction is a frequent complication of coronary artery surgery as determined by serial ECGs. In this study, approximately 50 per cent of these patients had diagnostic elevations of SGOT or LDH.

Acute coronary embolism complicating bacterial endocarditis: Operative treatment

A patient with bacterial endocarditis and no previous history of angina substained an acute anterolateral myocardial infarction while awaiting surgery. Selective coronary arteriography revealed a filling defect in the left anterior descending coronary artery with limited flow beyond the area of occlusion. A calcific embolus from the infected aortic valve was removed at the time of valve replacement, and the patient had an uneventful immediate postoperative course. Late postoperatively paravalvular aortic regurgitation recurred before and after a second repair.

Bioprosthetic valve longevity in the elderly: An 18-year longitudinal study

The issue of bioprosthetic valve durability has become of critical importance as the number of elderly patients requiring valve operation has continued to increase. Our previous study showed bioprosthetic valve durability to be in excess of 83% at 13 years for patients 70 years of age and older at the time of implantation. There is limited follow-up data in the literature beyond this time point, however. Accordingly a retrospective analysis was conducted of all patients with bioprosthetic valves who were 70 years of age and over at the time of implantation. From September 1974 to April 1994, 1007 patients 70 years of age and over underwent valve replacement using a porcine bioprosthesis. The patients ranged in age from 70 to 104 years (mean, 75.6 +/- 4.3 years). There were 549 men (54.5%) and 458 women (45.5%). Preoperatively 98.8% of the patients were in New York Heart Association functional class III or IV. Operation was performed as an emergency in 66 patients (6.6%). The hospital mortality was 10.9% (110 patients), with 897 hospital survivors. There were 961 valves at risk. Follow-up extended from 1 month to 18.8 years (mean, 56.6 months). The cumulative follow-up is 4232.3 patient-years. A total of 31 valves failed, 12 in the aortic position and 19 in the mitral position (p < 0.0024). The causes of valve failure have included structural deterioration (16 valves), prosthetic endocarditis (7 valves), nonstructural dysfunction (5 valves), prosthetic thrombosis (1 valve), and other (2 valves).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of stent mounting on tissue valves for aortic valve replacement.

Stent mounting of homograft valves was first reported by our group in 1968. Since then, there has been question as to whether or not stent mounting of bioprostheses adversely affects the incidence of structural deterioration in aortic valve replacement. Between November 1967 and July 1988, 571 consecutive patients underwent valve replacement with a stented or unstented homograft. There were 351 men (61.5%) and 220 women (38.5%). The mean age of the group was 49.2 years (range 18 to 79 years). Five hundred thirty‐four patients left the hospital (30‐day overall mortality 6.5%). Follow‐up extends from 6 months to 22 years with a mean of 7.6 years. The cumulative follow‐up for the series was 4,095.9 patient‐years. Hospital mortality, early technical failure, and prosthetic valve endocarditis were considered censoring events and excluded from this study. Actuarial analysis revealed a significant difference (p < 0.02) in the freedom from structural valve deterioration for unstented and stented isoiated aortic valve replacement. Age (50 and under, and over 50) does not appear to be a factor In structural deterioration in unstented homografts but does influence the rate of failure in stented homografts (p < 0.05). These results clearly indicate that stent mounting adversely affects tissue valve durability with aortic valve replacement. Moreover, age correlates with structural deterioration if valves are stented and does not if they are unstented. Based on these results, the use of unstented bioprostheses should be reevalvated, along with the design of porcine valve stents.

Acute myocardial infarction and ischemic injury during surgery for coronary artery disease

The incidence of myocardial infarction, acute ischemic injury, and associated serum enzyme abnormalities has been evaluated in four operations involving the coronary circulation. The highest incidence of infarction was associated with internal mammary implantation (Vineberg procedure). There was no significant difference in the incidence of infarction, ischemic injury, or abnormal enzyme levels between patients with stable angina and those with unstable angina who had vein bypass surgery. In operations involving combined vein bypass grafting and valve replacement surgery, the incidence of abnormal serum enzyme elevations was higher than in any other procedure. The incidence of infarction and acute ischemic injury in combined operations was similar to that in other procedures but this may have been due to the difficulty in the ECG diagnosis of infarction in this group of patients, most of whom had abnormal preoperative ECGs.

The effect of contrast media on the isolated perfused canine heart.

The intravascular injection of contrast medium produces a rise of ventricular filling pressure which may reflect blood volume expansion, a negative inotropic effect on the myocardium, and/or a decrease in ventricular diastolic compliance. This phenomenon was studied by randomly infusing three substances, Renografin-76, 1% saline and 38% sucrose, into the aortic root of the isolated perfused canine heart. The preparation was modified by having an inflated ballon within the left ventricular cavity so that the end diastolic ventricular volume and afterload were fixed. A dose-related depression of left ventricular systolic pressure and peak dP/dt due to contrast media occurred, without a significant change in the left ventricular diastolic pressure. This decrease in ventricular contractility due to Renografin-76 could not be attributed entirely to either a saline or an osmotic effect. No significant changes were observed in left ventricular diastolic compliance. Sucrose was found to exhibit a marked positive inotropic effect.

The Angell-Shiley Porcine Xenograft

A 4-year clinical experience with fresh allograft tissue valves prompted a trial of 0.5% buffered glutaraldehyde as a valve fixative and sterilant. Tanned allograft and porcine xenograft valves were inserted into experimental animals, and, beginning in 1970, similar valves were implanted in a series of patients now totaling 312. The clinical results are excellent. The 5-year valve-related mortality is 6% for patients who had mitral valve replacement and 16% for those with aortic valve replacement. To date, the incidence of thromboembolism is 1.3% per patient-year, and valve-related morbidity and mortality for the combined groups is 27.4%. Valve stent design has evolved from symmetrically configured metal to anatomically molded plastic. The maintenance of natural valve configuration has optimized leaflet coaptation and support, decreased tissue stress, and eliminated valve-stent dehiscence and tissue rupture seen in valves deformed to fit symmetrical stents. Stent design, controlled glutaraldehyde solutions, and fixation techniques have improved leaflet flexibility and reduced valve orifice to annulus diameter ratios, thus producing transvalvular gradients comparable to both mechanical and modified orifice tissue valves. To date, tissue failure, observed in only 1.0% (3 of 287) of patients, is the result of calcification (2 patients) and cusp rupture due to incomplete fixation (1 patient).

Bioprosthetic Valve Durability in the Elderly: The Second Decade

With an increasing number of elderly patients requiring cardiac valve surgery, the topic of bioprosthetic durability becomes critically important. Previous reports have shown expected survival of bioprosthetic valves to be in excess of 95% at 9 years. However, primary tissue failure appears to accelerate at the end of the first decade and there is limited data into the second decade. With this in mind, we proceeded to analyze all bioprosthetic valves implanted in patients 70 years of age and older. From September 1974 to December 1990, 781 patients underwent valve replacement using a bioprosthesis. Ages ranged from 70 to 88 years with a mean of 75.1. There were 423 males (54.2%) and 358 females (45.8%). Preoperatively, 99.0% of the patients were in either New York Heart Association functional Class III or IV. Fifty‐nine patients (7.6%) were done as emergencies. Six hundred ninety‐four patients left the hospital (30‐day overall mortality 11.1 %). In this cohort, there were 733 valves at risk. Follow‐up extended from 1 to 186.0 months with a mean of 52.9, which resulted in 3,059.9 patient‐years of cumulative follow‐up. Bioprosthetic Survival: A total of 23 valves failed in the series; 15 primary tissue failures, seven from endocarditis, and one perivalvuiar leak. Actuarial survival at 7 years was 94.5% ± 1.4% standard error of the mean (SEM; 168 valves at risk) and at 13 years, 83.7% ± 4.8% SEM (11 valves at risk). This analysis provides further documentation of the long‐term favorable durability of the bioprosthesis when utilized in patients 70 years of age and over.

Mitral Valve Reconstruction for Mitral Regurgitation

The history of mitral valve reconstruction mirrors the history of cardiac surgery. As early as 1902, the possibility of opening stenotic mitral valves was first suggested by Brunton in Lancet.’ The first clinical surgical successes with mitral commissurotomy are attributed to Cutler and Levine in 1923,2 and Souttar in 1925.3 Published series of closed commissurotomies by Harken in 19484 and Bailey in 194g5 established this surgical procedure and validated its effectiveness. Lillehei6 in 1958 focused attention on this subject and heralded the modern era of repair of stenotic and regurgitant mitral valves under direct vision. Although mitral valve repair procedures continue to generate widespread interest, several factors have limited their application to a relatively few medical centers in the United States. First and foremost was a requirement for surgeons interested in the art of reconstruction; second, the widespread use of antibiotics in childhood respiratory infections in the United States dramatically reduced the number of patients suffering from rheumatic mitral valve disease; and third, the development of the heart-lung machine by Gibbons in 1953 and the production of suitable prosthetic valve substitutes in 1960 signaled the end of reliance on repair of the diseased.mitral valve as the procedure of choice. The alternative of mitral valve replacement as opposed to the more elegant, perhaps, but more time-consuming and less predictable mitral valve repair proved a

Aortic valve replacement with the fresh valve homograft.

Abstract Forty patients with isolated aortic valve disease have undergone valve replacement with the fresh aortic homograft. Five hospital deaths (12.5 per cent) and one late death occurred. None was due to homograft dysfunction. The surviving patients are all either asymptomatic or greatly improved. Three patients were discharged from the hospital with diastolic murmurs (one in the past thirty-one patients.) Seven additional patients developed diastolic murmurs one and one-half to four months postoperatively. None has signs of significant aortic insufficiency. The technic of insertion with a double suture line and the use of relatively fresh, sterilely collected valves appear to be important in minimizing the incidence of immediate diastolic murmurs. No instance of homograft deterioration has appeared in up to ten months of observation. Available evidence indicates that fresh homograft valves maintain a more normal histologic structure and are less subject to late degenerative changes than valves sterilized with betapropiolactone and/or freeze-dried.