Morbidity and mortality of coronary bypass grafting in patients 70 years of age and older

The hospital mortality and major factors contributing to hospital morbidity and postoperative length of stay were examined in 597 consecutive patients 70 years of age and older who underwent isolated coronary artery bypass grafting (CABG) between January, 1978, and December, 1983. The mean age of the patients was 73 years, and 66% were men. Unstable angina was present in 59% of patients, left main coronary disease in 13%, and moderate or severe left ventricular dysfunction in 10%. The mean number of arteries grafted per patient was 3.4. The hospital mortality was 2.7% (16 patients) and was higher than the mortality among 4,125 patients less than 70 years of age (0.4% in 18 patients) operated on during the same interval (p less than 0.001). In multivariate regression analyses, age of 80 years or greater, evolving myocardial infarction, serious coexisting illness, major left ventricular dysfunction, emergent operation, and the development of major postoperative complications were significant (p less than 0.05) independent predictors of increased hospital mortality. Major complications occurred in 135 patients (23%). In multivariate analyses, the presence of vascular disease, serious concomitant illness, and the need for urgent or emergent operation were significant independent predictors of the development of major postoperative complications. The mean duration of postoperative hospital stay was 10.6 +/- 6 (standard deviation) days. In multivariate analyses, the development of major postoperative complications was the only variable independently predictive of prolonged hospital stay. With current techniques, CABG procedures can be safely performed in the elderly with mortality and morbidity rates only slightly higher than those in younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Late results of surgical and medical therapy for patients with coronary artery disease and depressed left ventricular function

Late survival and freedom from myocardial infarction were determined for 192 patients with coronary artery disease and depressed left ventricular ejection fraction at rest (less than or equal to 35%) determined by biplane angiography who were evaluated between 1970 and 1977. Seventy-seven patients had coronary artery bypass grafting and 115 patients were treated medically and were considered surgical candidates. The medical and surgical groups were comparable in all baseline characteristics examined except frequency of three vessel disease and angina pectoris, which occurred in a significantly greater percent of the surgically treated patients (p less than 0.01). Only three medically treated patients (2.6%) underwent coronary bypass grafting in the follow-up period. Seven year actuarial survival was 63% in the surgical and 34% in the medical group (p less than 0.001). Ninety-three percent of patients in the surgical group and 81% of those in the medical group were free of nonfatal myocardial infarction (p = 0.01), and 62 and 33%, respectively, were alive and free of myocardial infarction (p less than 0.001) at 7 years. Significant differences in survival favoring surgical treatment were observed for the subsets of patients with an ejection fraction of 25% or less (p = 0.0002) and 26 to 35% (p = 0.01), and for the subsets with three vessel coronary disease (p less than 0.001), normal left ventricular end-diastolic volume (less than or equal to 100 ml/m2) (p = 0.005) and elevated end-diastolic volume (greater than 100 ml/m2)(p = 0.001). After adjustment for other important prognostic variables, the type of treatment remained significant in predicting the relative risk (medical to surgical) of mortality at 5 and 7 years (2.58 and 2.12, respectively). These data corroborate the trends observed in several randomized trials of medical and surgical therapy in patients with abnormal left ventricular function. If hospital mortality for coronary artery bypass grafting is less than 5%, substantial benefit can be anticipated for the majority of patients with depressed ventricular function.

Early results of valve replacement with the Björk-Shiley convexoconcave prosthesis

The Björk-Shiley convexoconcave prosthetic valve has design characteristics that may result in a lower incidence of thromboembolic complications than the conventional spherical Björk-Shiley prosthesis. We evaluated the results of valve replacement with the convexoconcave prosthesis in 248 patients receiving 301 prosthetic valves between March, 1979, and June, 1981. One hundred thirteen patients had aortic valve replacement (AVR), 73 had mitral valve replacement (MVR), and 62 had multiple valve replacement. Two hundred nine (84%) were in New York Heart Association Class III or IV. The median duration of follow-up was 13 months, and follow-up information was available for 246 (99%) of the patients. The actuarial incidence of freedom from thromboembolism at two years was 98% in the AVR group, 97% in the MVR group, and 87% in the group having multiple valve replacement. There were no documented episodes of valve thrombosis or mechanical failure and no fatal thromboembolic complications. The absence of valve thrombosis is in marked contrast to the results reported with the spherical disc valve. Although longer follow-up is necessary, it appears that the convexoconcave design represents a major improvement in the Björk-Shiley prosthesis.

Penetrating cardiac trauma

During a 10 1/2 year interval ending in June 1980, 47 patients with penetrating cardiac trauma were managed at The University of Alabama Medical Center. Thirty-nine patients (83%) were male. Mean age was 31 years (range, 13 to 69). Thirty-two patients (68%) sustained stab wounds (SW) and 15 patients (32%) gunshot wounds (GSW). Forty-two patients (89%) arrived hypotensive (systolic blood pressure less than 90 mm Hg). Twenty-seven patients (57%) had evidence of cardiac tamponade (central venous pressure greater than 15 cm H2O) and 25 of these 27 patients were also in shock. Forty patients (85%) presented with a normal sinus rhythm and seven patients (15%) had an idioventricular rhythm or asystole. Overall mortality was 23% (11 of 47 patients). Forty-three per cent of the patients sustaining GSW (6/14) died compared to 17% (5/33) of the patients with SW (p = 0.04). Mortality for the patients in shock was 26% and for those with cardiac tamponade 15%. Mortality was 16% for the patients with both shock and cardiac tamponade. Thirteen per cent of the patients in normal sinus rhythm died, while 87% of the patients with idioventricular rhythm or asystole died (p less than 0.0001). Mortality in penetrating cardiac trauma remains high, particularly in patients with GSW and in those patients presenting with an idioventricular rhythm or asystole.

Hydroxyethyl starch versus albumin for colloid infusion following cardiopulmonary bypass in patients undergoing myocardial revascularization

Hydroxyethyl starch or hetastarch (HES), a synthetic colloid for intravascular volume expansion, was compared with albumin after coronary artery operations in 30 patients (15 in each study group). Cardiac index, atrial pressures, heart rate, and systolic blood pressure were similar in both groups. There were no differences in cumulative urine output at 24 hours or in weight change during the first 7 postoperative days. Values for colloid osmotic pressure, as well as for this variable minus left atrial pressure, were lowest soon after bypass but returned to baseline within 4 hours, with no difference between groups in the first 24 hours or 7 days after operation. Coagulation variables were similar, but prothrombin and partial thromboplastin times were higher 12 hours postoperatively and fibrinogen level was lower 7 days postoperatively in the patients receiving HES. There was no clinical evidence of excessive bleeding, although cumulative chest drainage at 12 and 24 hours was slightly higher in the HES group (p = 0.09 and 0.08, respectively). We conclude that hetastarch is a safe and effective colloid to use following coronary operations.

Combined aortic valve replacement and myocardial revascularization. Experience with a cold cardioplegic technique

The authors reviewed their experience with combined aortic valve replacement and coronary artery bypass grafting using a standardized cold cardioplegic technique for intraoperative myocardial protection in 54 consecutive patients during a 5-year interval ending in May 1982. Calcific aortic stenosis was the most common indication for aortic valve replacement. Thirty-seven patients (69%) had greater than 50-60% stenoses in at least two of the three major coronary arterial systems. No patient with combined aortic valvular and coronary artery disease had only valve replacement during the study interval, and no patient was refused operation. The mean number of arteries grafted was 2.4. There was one hospital death (1.9%), and one patient (1.9%) had electrocardiographic evidence for perioperative myocardial infarction. One additional patient required postoperative intra-aortic balloon pumping. There have been four late deaths in the followup period extending to 65 months. Survival at 3 years for the entire group was 87%, for the patients with aortic stenosis was 95%, and for the patients with aortic regurgitation or mixed lesions was 65%. There were no cardiac-related deaths among the patients with aortic stenosis and one non-fatal myocardial infarction in the follow-up period. The results with this technique of intraoperative myocardial protection are superior to those reported with previously employed methods (coronary perfusion, hypothermic ischemic arrest) and indicate that coronary artery bypass grafting should be performed in all patients with coexisting aortic valvular and coronary artery disease who require valve replacement. A substantial benefit (increased survival, decreased late myocardial infarction) may exist for the subgroup of patients with aortic stenosis.

Late results after mitral valve replacement with the Björk-Shiley and porcine prostheses

The late results of isolated mitral valve replacement were retrospectively evaluated in 357 patients receiving a Björk-Shiley (B-S) tilting disc prosthesis and 96 patients receiving a porcine bioprosthesis (PB) (Vascor or Carpentier-Edwards) between March, 1973, and July, 1978. The groups were comparable with regard to age, sex, New York Heart Association functional class, preoperative cardiac rhythm (sinus or atrial fibrillation), left atrial size (normal or enlarged), and presence of thrombus in the left atrium at operation. All of the B-S and 14 of the PB patients received long-term anticoagulant therapy. The median duration of follow-up was 46 months in the B-S group and 32 months in the PB group. At 5 years, survival was 70% for the B-S and 68% for the PB groups (NS). The percentage of patients free of thromboembolic episodes was 77% for the B-S and 78% for the PB groups (NS). Fifty-six percent of the B-S and 49% of the PB patients were alive and free of thromboembolism, complications related to anticoagulant therapy, or other valve-related complications (dehiscence, degeneration, or endocarditis) (NS). The presence of atrial fibrillation, enlarged left atrium, preoperative thromboembolic episodes, and left atrial thrombus had no effect on the incidence of thromboembolic complications with either prosthesis. From this analysis, it appears that the major advantage of the PB over the B-S prosthesis is its use in patients in whom long-term anticoagulation is contraindicated.

Factors associated with periprosthetic leakage following primary mitral valve replacement: with special consideration of the suture technique

Among 435 patients without native valve endocarditis who were followed up to 69 months after primary mitral valve replacement, 25 developed documented periprosthetic leakage. In 10 patients this was associated with prosthetic valve infection. No evidence of prosthetic infection was found in the remaining 15 patients with documented leakages, and they form the basis of the study. Multivariate Cox regression analysis indicated that leakage in the absence of infection was strongly associated with the use of small monofilament suture (2-0 or 3-0 versus 1-0) in a continuous suture technique (92.0% actuarially leak free by 43 months versus 99.0% for continuous 1-0 monofilament sutures or pledgeted mattress sutures; p = 0.01) and with annular calcification (p = 0.01). We did not find (p greater than 0.2) the functional type of mitral valve lesion or its pathology, or the type and size of prosthesis used, to be incremental risk factors.

Surgical treatment of aneurysms of the descending thoracic aorta: an analysis of 85 patients

We have reviewed our experience with resection of 85 aneurysms of the descending thoracic aorta during a ten-and-one-half year interval ending in June, 1980. There were 39 arteriosclerotic aneurysms, 35 aneurysms associated with chronic aortic dissection, and 11 posttraumatic aneurysms. During repair, a temporary shunt was used in 56 patients (66%), partial (venoarterial) cardiopulmonary bypass (CPB) in 19 patients (22%), and simple aortic cross-clamping in 10 patients (12%). Hospital mortality was 11.8%, and was unrelated to the type of aneurysm or operative method. Spinal cord injury developed in 3 of the 83 patients surviving operation (3.6%), and occurred once with each of the three operative methods. Among the 82 operative survivors without preoperative renal failure, postoperative renal failure requiring hemodialysis occurred in 2 of the 10 patients who had simple aortic cross-clamping (20%), 2 of the 54 who had a shunt (3.7%), and in none of the 18 who underwent partial CPB (p = 0.049). Postoperative renal dysfunction (a rise in the preoperative blood urea nitrogen and creatinine levels of 50% or more) occurred in 27 of the 53 patients (51%) who had preoperative and postoperative determinations. Age, intraoperative hypotension, and the use of simple aortic cross-clamping were significant (p less than 0.05) independent predictors of postoperative renal dysfunction. Intraoperative blood loss and the incidence of reoperation for bleeding did not differ significantly among the three operative methods. We conclude that the aneurysm resection technique and the development of intraoperative hypotension have an important effect on postoperative renal function. Partial CPB may represent the optimal method for preservation of renal function, and may also be the method of choice for elderly patients with preexisting renal dysfunction.

Costs and benefits associated with treatment for coronary artery disease

Direct and indirect costs of medical and of surgical treatment are presented for patients entered into the Birmingham portion of the Coronary Artery Surgery Study. For comparison, similar results are shown for the Birmingham portion of the national Cooperative Unstable Angina Study. In the Unstable Angina Study, mean inpatient costs at the end of 1 year in the study were $6867 for medical therapy, $10,574 for surgical therapy and $23,045 for those who failed medical therapy and required late surgery. A stepwise multiple regression analysis shows that the single best predictor of cost was the number of myocardial infarctions that the patient had while in the study. A discriminant-function analysis identified 85% of the medical patients who required late surgery. A significantly lower proportion of surgical than medical patients returned to work. Total inpatient costs for patients in the Coronary Artery Surgery Study (i.e, patients with stable angina) were $3432, $11,100 and $13,554 for medical, surgical and late surgical patients, respectively, for the first year in the study. There was no significant difference in the percentage of medical and surgical patients who were working at the end of 1 year. According to their own perceptions, the surgical group was in the best and the late surgical group in the worst health.

Survival of medically treated patients in the coronary artery surgery study (CASS) registry

The objective of this study was to evaluate the impact on survival of the anatomic extent of obstructive coronary artery disease and of two measures of left ventricular (LV) performance. This study is based on 20,088 patients without previous coronary artery bypass graft surgery who were enrolled in the registry of the National Heart, Lung, and Blood Institute Coronary Artery Surgery Study from 1975 to 1979. The cumulative 4-year survival of medically managed patients was analyzed to determine the survival of specific subsets of patients with obstructive coronary disease. The vital status of 99.8% of the patients was known. The 4-year survival of medically treated patients with no significant obstructive disease was 97%, in contrast to 92%, 84% and 68% in patients with one-, two- and three-vessel disease, respectively. The presence of left main coronary artery disease decreased survival significantly. The 4-year survival decreased from 70% to 60% in patients with three-vessel disease when significant obstruction of the left main coronary artery was also present. Patients with significant coronary artery disease who had an ejection fraction of 50--100%, 35--49%, and 0--34% had a 4-year survival of 92%, 83% and 58%, respectively. The systolic contraction pattern was assessed in five selected segments and given a score of 1--6, with a score of 1 for normal function, increasing to 6 if an aneurysm was present. In a patient with normal LV contraction in all five segments of the LV ventricular angiogram, the LV score would equal 5. Patients with an LV score of 5--11, 12--16 and 17--30 had 4-year survivals of 90%, 71% and 53%, respectively. Patients with good LV function (a score of 5--11) had a 4-year survival of 94%, 91% and 79% for one-, two- and three-vessel disease, respectively. Patients with poor left ventricular function (score of 17--30) had a 4-year survival rate of 67%, 61% and 42% in one-, two- and three-vessel disease, respectively. Thus, LV function is a more important predictor of survival than the number of diseased vessels.

Simultaneous myocardial revascularization and carotid endarterectomy

Two methods for performing simultaneous carotid endarterectomy and coronary artery bypass grafting (CABG) were compared in 73 patients. A technique for performing carotid endarterectomy during cardiopulmonary bypass providing hypothermic cerebral protection was used in 37 patients (group 1). The 36 other patients (group 2) underwent carotid endarterectomy immediately before cardiopulmonary bypass was instituted. The mean age, New York Heart Association functional class, ventricular function and extent of carotid disease were similar in the two groups. The proportion of patients with previous myocardial infarction or stroke was higher in group 1 (p less than 0.05). One permanent neurologic deficit (technical error) and one transient neurologic deficit occurred in group 1 and none in group 2 (NS). Twenty-seven patients (37%) had left main disease, compared with an institutional incidence of 14.2% for all coronary operations. Five of seven patients who died early (three in group 1 and four in group 2) had left main disease. No advantage of one method over the other could be demonstrated. Patients with left main coronary artery disease and carotid disease have an increased operative risk.

Employment status after coronary artery bypass surgery

With a few exceptions, prevailing data on return to work after coronary artery bypass surgery indicate no net gain in employment status for at least several years after the operation. Despite the improved surgical experience and advances in the medical management of postoperative patients, only limited employment benefits occur after surgery, and no gains in work rehabilitation over the past decade have been noted. Several characteristics--preoperative work status, nonwork income, occupation, relief of symptoms, age, perception of health, education and severity of disease--appear to be important for estimating the likelihood of employment after surgery. Other influences, such as attitudes of the family, employers and physicians, undoubtedly alter the probability of return to the work force, but are less well documented. Unless constructive approaches toward work rehabilitation are made, the possibility of return to gainful employment should not be considered an indication for or a necessary consequence of coronary artery bypass surgery.

Unstable angina pectoris: management based on available information

Several prospective randomized studies of medical or surgical therapy have not shown that either form of management alone is uniformly superior with respect to mortality for unstable angina pectoris. Patients managed medically have a greater incidence of angina pectoris. Earlier studies indicated a higher rate of nonfatal myocardial infarction with urgent surgery. Present management includes hospitalization and early intensive medical therapy with nitrates and, usually, beta-blocking agents. Coronary arteriography is advised within a few days. If the patient has left main coronary artery disease or three-vessel disease, early coronary artery bypass graft surgery within days to a couple of weeks is advised. Otherwise, medical management is advised and elective surgery can be performed if the patient remains symptomatic.

Detection of myocardial injury after coronary artery bypass grafting using a hypothermic, cardioplegic technique

Fifty patients undergoing isolated coronary artery bypass grafting procedures using a clear, cold cardioplegic solution, topical hypothermia, and reduced systemic flow for intraoperative myocardial protection were evaluated for myocardial injury by serial plasma creatine kinase-MB isoenzyme (CK-MB) measurements and electrocardiograms. Forty-one (82%) of the patients had three-vessel disease. Preoperative left ventricular contractility determined angiographically was normal in 13 patients (26%), mildly abnormal in 26 (52%), and moderately or severely abnormal in 11 (22%). The number of arteries grafted ranged from 2 to 6 (mean, 3.5). The mean duration of aortic clamping was 38.6 +/- 1.6 minutes. There were no hospital deaths. Enzymatic and electrocardiographic (ECG) evidence of myocardial infarction occurred in 1 patient. Nonspecific ECG changes occurred in 16 patients (32%), and th electrocardiograms were unchanged in the remaining 33 patients (66%). In the 49 patients without ECG evidence of infarction, the mean peak plasma CK-MB value, which occurred 6 hours after the onset of cardiopulmonary bypass, was 7.9 +/- 0.8 IU/L (standard error of the mean) and the mean integrated area 158 +/- 19.5 IU/L X hours. There was no correlation between these CK-MB values and the extent of disease, number of arteries grafted, or the duration of myocardial ischemia. These data document a low incidence of perioperative myocardial injury with this technique, and can serve as a baseline for comparison with other techniques for intraoperative myocardial protection in this setting.

Hospital mortality of re-replacement of the aortic valve. Incremental risk factors

A total of 200 aortic vale re-replacements were performed between Jan. 1, 1975, and July 1, 1979. The re-replacements (RRP) were an isolated procedure or combined with coronary artery bypass grafting or resection of ascending aortic aneurysm. Ten patients (5%) died in hospital, compared with 24 (2.9%) among 842 patients undergoing isolated or combined initial aortic valve replacement (AVR) (p = 0.12). The mode of death was cardiac failure in six of the 10 patients, hemorrhage in two (from accidents at repeat sternotomy), and neurologic deficits in two (each with innominate vein transection at repeat sternotomy repaired by ligation). There were seven (3.9%) hospital deaths among 181 first RRP (p for difference from initial AVR = 0.5), but three (15%) of 19 died after the second or third RRP (p = 0.001). By simple contingency table analysis, preoperative New York Heart Association (NYHA) Class IV increased the risk of hospital death after RRP (p = 0.002), as did prosthetic valve endocarditis (p = 0.0005) and the use of cold ischemic arrest (p = 0.03). Logistic multivariate analysis showed advanced NYHA functional class (p = 0.02), use of cold ischemic arrest (p = 0.09), and increased aortic cross-clamps time (p = 0.03) to be incremental risk factors. Recommendations for reducing hospital deaths in the event of RRP are (1) reoperate before severe hemodynamic deterioration occurs, (2) plan and conduct the operation to minimize accidents from repeat sternotomy and dissection, (3) keep aortic cross-clamp time as short as possible, and (4) employ cold cardioplegia.

Hemodynamic responses to anesthetic induction with midazolam or diazepam in patients with ischemic heart disease

Hemodynamic responses to induction of anesthesia with midazolam maleate and diazepam were compared in patients with ischemic heart disease. While breathing 100% oxygen, 10 patients (group M) received midazolam maleate, 0.2 mg/kg, and 10 patients (group D) received diazepam, 0.5 mg/kg. In addition, 10 patients (group MN) breathing 50% nitrous oxide in oxygen received midazolam, 0.2 mg/kg. Patients in group M had a small but statistically significant (p less than 0.05) decrease (vs awake control values) in systemic and pulmonary arterial blood pressure, pulmonary arterial occluded pressure, stroke index, and left and right ventricular stroke work indices. Patients in group D experienced statistically significant decreases in systemic blood pressure. The only statistically significant differences between groups M and D occurred 5 minutes followed drug administration: heart rates were higher and systemic pressures and left ventricular stroke work indices were lower following midazolam. Hemodynamic changes following midazolam and nitrous oxide were similar to those observed in patients given midazolam and 100% oxygen. Patients in all three groups responded to endotracheal intubation with transient increases in blood pressure, heart rate, and systemic vascular resistance, but the hemodynamic values spontaneously returned toward control levels within 2 to 5 minutes. Although differing somewhat, midazolam, like diazepam, provided rapid, hemodynamically stable induction of anesthesia in patients with ischemic heart disease.