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Biomedical subjects

G C Kaiser

Publications and source records attributed to G C Kaiser.

At least 73 records · Page 4Linked to original sources
PubMed1986

Should airline pilots be eligible to resume active flight status after coronary bypass surgery?: a CASS registry study.

Medical certification to return to work after coronary bypass surgery in occupations that carry a risk to public safety is controversial, particularly for airline pilots. To address this issue, 10,312 patients from the CASS registry who underwent coronary bypass surgery were studied and 2,326 men with clinical and postoperative characteristics similar to those of the average airline pilot who might apply to renew his license after surgery were selected. The 5 year probability of remaining free of an acute cardiac event, defined as acute coronary insufficiency, myocardial infarction or sudden death, was 0.92 +/- 0.01 (mean +/- SE) for the 1,207 men without previous myocardial infarction and 0.98 +/- 0.01 for the 122 men who never smoked and did not have a history of hypertension. Among the 1,119 men with a previous myocardial infarction, the probability of remaining free of acute cardiac events was 0.91 +/- 0.02 and 0.92 +/- 0.02 when left ventricular contraction score was 5 to 9 and 10 or greater, respectively. In this patient subgroup, mortality rate was similar to that of the age-matched U.S. male population when the left ventricular contraction score was 5 to 9 (4.0% versus 4.3%; p = NS) but significantly worse when the left ventricular contraction score was 10 or greater (7% versus 4.2%; p = 0.05). The data from this CASS registry study are pertinent to the question of operationally unlimited first-class medical certification of carefully selected airline pilots after coronary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

The role of coronary bypass surgery for 'left main equivalent' coronary disease: the Coronary Artery Surgery Study registry.

Combined proximal left anterior descending and proximal left circumflex, or "left main equivalent" (LMEQ), disease defines a prognostic angiographic high-risk patient population. We assessed the effect of coronary bypass surgery compared with medical therapy in 903 patients with LMEQ disease by stratified life table and Cox regression analysis. The 5 year survival rates of the 639 and 264 patients who received surgical vs medical therapy was 85% vs 55%, respectively (p less than .001). Analysis of patient subsets stratified by age, angina class, right coronary disease, and ejection fraction revealed a significant survival benefit for surgically treated patients in most strata. Cox regression analysis revealed improved survival for surgically treated patients after adjustment for important baseline variables known to influence prognosis. Surgically treated patients had significantly less angina and need for antianginal drugs compared with the medically treated group. When the Coronary Artery Surgery Study randomized and randomizable LMEQ patients were analyzed, coronary bypass surgery improved 5 year survival when preoperative ejection fraction was under 0.50 but not when ejection fraction was 0.50 or higher. Thus coronary bypass surgery prolongs and improves quality of life (as defined by angina status and need for antianginal drugs) in most patients with LMEQ disease but does not appear to improve 5 year survival in a small subset of LMEQ patients who are asymptomatic after myocardial infarction or who have mild chronic stable angina and are under age 65 with well-preserved left ventricular function.

Aged↗
PubMed1985

Comparison of coronary artery bypass surgery and medical therapy in patients 65 years of age or older. A nonrandomized study from the Coronary Artery Surgery Study (CASS) registry.

We compared the results of coronary artery bypass surgery with those of medical therapy alone in 1491 nonrandomized patients 65 years of age or older. Cumulative survival at six years (adjusted for major differences in important base-line characteristics) was 79 per cent in the surgical group and 64 per cent in the medical group (P less than 0.0001). At five years, chest pain was absent in 62 per cent of the surgical group and 29 per cent of the medical group (P less than 0.0001). Analysis by the Cox proportional-hazards model suggested an independent beneficial effect of surgery on survival (P less than 0.0001). Patients were divided into risk quartiles on the basis of preoperative predictors of survival identified by the Cox model. Surgical benefit was greatest in "high-risk" patients (those in the two quartiles containing patients with the poorest prognosis). Among 234 "low-risk" patients with mild angina, relatively good ventricular function, and no left main coronary artery disease, there was no survival difference between those treated medically and those treated surgically. We conclude that in specific higher-risk subsets of non-randomized patients 65 years of age or older, coronary bypass surgery appeared to improve survival and symptoms in comparison with medical therapy alone. These conclusions must be tempered by consideration of the limitations of nonrandomized studies, particularly since patients in the two treatment groups differed substantially with regard to important base-line characteristics.

Aged↗
PubMed1985

Surgical survival in the Coronary Artery Surgery Study (CASS) registry.

The overall surgical survival data in the Coronary Artery Surgery Study (CASS) registry have not been published to date, pending the report of the randomized medical-surgical comparison (CASS randomized trial). Non-randomized surgical survival data from the CASS registry are given in this article. The overall medical survival data from the registry were reported previously as a natural history study. There were 8,991 patients in the registry portion of CASS who had primary isolated coronary artery bypass grafting and 8,971 with follow-up of more than 30 days. The 5-year survival for all 8,971 patients was 90%, and the operative mortality was 2.37%. Patients with left main coronary artery disease had an operative mortality of 3.84% and a 5-year survival of 85%, while patients with lesions in other vessels had an operative mortality of 2.12% and a 5-year survival of 91%. Among patients without left main coronary disease, the 5-year survival was 93% in those with single-vessel and 92% in those with double-vessel disease (operative mortality was 1.50% and 1.92%, respectively) and 88% in patients with triple-vessel disease (operative mortality was 2.62%; p = 0.009). When results for patients with left main coronary artery obstruction were compared with those for triple-vessel disease, the 5-year survival figures were 85% and 88%, respectively (p = 0.02) and the operative mortality, 3.84% and 2.62%, respectively (p = 0.03). Patients with normal or nearly normal left ventricular (LV) function (i.e., LV segmental wall motion scores ranging from 5 through 11) had a 5-year survival of 92% and an operative mortality of 1.97%. Patients with moderate impairment (LV score range, 12 through 16) had a 5-year survival of 80% and an operative mortality of 4.21%. In those with poor ventricular function (LV score of 17 or greater), the 5-year survival was 65% and the operative mortality was 6.21%. The difference in survival among the three groups was significant (p less than 0.0001). Of 29 variables used in a stepwise Cox regression analysis, LV wall motion score, congestive heart failure score, age, number of operable vessels, smoking history, LV end-diastolic pressure, and percent of left main coronary artery stenosis were found to have a significant effect on long-term survival (excluding 30-day mortality), and these variables plus surgical priority and height influenced surgical mortality. When height was used in the Cox proportional hazards model, female sex was no longer a significant variable.

Adult↗
PubMed1985

The importance of biventricular failure in patients with postoperative cardiogenic shock.

To evaluate the importance of severe biventricular failure in patients with postcardiotomy ventricular failure, we analyzed the data from 30 patients treated with ventricular assist devices (VADs) over a five-year period. All patients had profound postoperative ventricular failure refractory to drugs and an intraaortic balloon (IAB). Evaluation of preoperative ventricular function did not allow prediction of which patients would require VADs. However, the development of perioperative myocardial infarction was an important determinant of the need for postoperative support with a VAD. Twenty patients received only a left VAD (LVAD). Four of them had isolated left ventricular failure; 3 were weaned, and 2 survived. None of the 16 patients with biventricular failure who received only an LVAD were weaned. Ten other patients with biventricular failure received biventricular support, either with a right VAD and IAB, or with two VADs. Of these 10 patients, 5 were weaned and 3 survived. Considering all 26 patients with biventricular failure, those receiving biventricular mechanical support (10) had a better chance (p less than 0.025) of being weaned (5/10) and surviving (3/10) than those who received only an LVAD (0/16). We conclude that biventricular failure is common in patients with postcardiotomy ventricular failure and is often the result of perioperative infarction. While patients with isolated left ventricular failure did well with an LVAD only, those with biventricular failure required biventricular mechanical support for survival.

Adolescent↗
PubMed1985

Intraoperative myocardial protection: a comparison of blood and asanguineous cardioplegia.

Cardiac arrest was achieved in 84 patients using asanguineous cardioplegia and in 97 patients using cold blood potassium cardioplegia. The patient groups were similar in age, sex ratio, and preoperative risk factors. Other than the cardioplegic solution used, the conduct of each operation was identical. There were no differences in mean total pump time (118 minutes for the asanguineous cardioplegia group versus 117 minutes for the cold blood cardioplegia group) or cross-clamp time (73.5 versus 70 minutes, respectively). However, the blood cardioplegia group had a greater number of distal anastomoses per patient (3.9 versus 3.7; p less than 0.05). Myocardial protection was assessed clinically and by serial electrocardiograms. Cellular integrity was determined by release of the myocardial isoenzyme of serum creatine kinase (CK-MB). Cellular morphology was studied in 6 randomly selected patients in each group by electron microscopic examination of left ventricular myocardial samples obtained before and after bypass. Three patients given blood cardioplegia and 5 given asanguineous cardioplegia required intraaortic balloon counterpulsation at termination of bypass. There were no ultrastructural changes in either group. Electrocardiographic changes (Minnesota code) occurred in 12 of 84 patients receiving asanguineous cardioplegia versus 12 of 97 patients receiving cold blood potassium cardioplegia. To maintain a satisfactory cardiac index (greater than 2.0 L/min/m2), 38 of 84 patients given asanguineous cardioplegia versus 25 of 97 patients given blood cardioplegia required inotropic support up to 24 hours postoperatively (p less than 0.05). Infarct size determined from CK-MB release was significantly greater (p less than 0.05) in patients given asanguineous cardioplegia (36.27 gm-equivalents) than in those given blood cardioplegia (26.7 gm-equivalents).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion↗
PubMed1985

CABG 1984: technical aspects of bypass surgery.

During the past 15 years coronary artery bypass surgery (CABG) has evolved into a procedure with low operative mortality and morbidity resulting in excellent improvement in lifestyle and improved longevity in some instances. Operative risk factors have been identified. Their significance has changed during this time. Currently, clinical congestive heart failure and emergency operation are the most commonly observed adverse results. Since the patients being operated upon, especially those emergent, are sicker, the improvements in mortality and morbidity with CABG are not due to patient selection, but rather to improvement in preoperative, intraoperative, and postoperative management. The major areas of management that have been responsible for the current status of CABG are myocardial protection, conduit selection and preservation, blood conservation, anesthetic management, pulmonary arterial catheter monitoring, pharmacologic unloading, intraaortic balloon assistance, cardiac assist devices, and arrhythmia control.

Adrenergic beta-Antagonists↗
PubMed1985

Survival following coronary artery bypass grafting in patients with severe angina pectoris (CASS). An observational study.

This observational study evaluates the effects of the severity of angina pectoris and the treatment method upon the survival of 4,209 patients in the Coronary Artery Surgery Study registry. In this nonrandomized study, these patients met the criteria used in the Coronary Artery Surgery Study randomized trial, except for the degree of angina pectoris and the method of selection of treatment. The 5 year survival rate was greater than or equal to 93% in patients with Class I and II angina pectoris and normal left ventricular function, regardless of the number of involved vessels or treatment received. Late survival of surgically treated patients with Class III and IV angina pectoris and normal left ventricular function was similar, regardless of the number of vessels involved (greater than or equal to 92% at 5 years). Nonoperatively treated patients with Class III and IV angina pectoris and normal left ventricular function had poorer 5 year survival rates, lowest (74%) in patients with three vessel disease (p less than 0.0001). This difference was also observed in patients with abnormal left ventricular function, three vessel disease, and Class III and IV angina pectoris; the 5 year survival rates were 82% for the operative group and 52% for the nonoperative group (p less than 0.0001). These data confirm the importance of clinical as well as anatomic factors in determining the prognosis of patients with ischemic heart disease and indicate that coronary artery bypass grafting can improve late survival in patients with triple vessel disease and severe angina pectoris.

Adult↗
PubMed1984

Potential for percutaneous transluminal coronary angioplasty before initial and repeat coronary artery bypass grafting in the Coronary Artery Surgery Study (CASS) Registry population.

Retrospective analysis of preoperative angiograms was conducted to determine potential candidacy for PTCA among the NHLBI Coronary Artery Surgery Study (CASS) Registry population undergoing initial and repeat CABG. Conservative criteria believed to be universally acceptable for PTCA were used. Patients were considered potential PTCA candidates if: (1) CABG had been performed to only 1 coronary artery system; (2) the critical disease was localized to the most proximal segment of that coronary artery system; (3) all distal segments of that coronary artery system were free of critical disease; and (4) the morphologic characteristics of the obstructing lesion were discrete and isolated. Left main CAD was excluded. Among persons who underwent initial CABG, 2.8% (261 of 9,369) were PTCA candidates, and 7.1% (20 of 283) of those who underwent repeat CABG were considered suitable for PTCA. The operative mortality risk of the PTCA candidates who underwent initial CABG was 0.4% (1 of 261). No PTCA candidates died during repeat CABG. Perioperative MI occurred in 2.3% (6 of 261) of the PTCA candidates who had initial CABG; none occurred among those who underwent repeat surgery. Total surgical complications occurred in 15.7% (41 of 261) of the PTCA candidates at initial CABG and in 5% (1 of 20) who had repeat CABG. These operative mortality and morbidity risks are lower than those reported for similar patients who undergo PTCA.

Adult↗
PubMed1984

Global left ventricular impairment and myocardial revascularization: determinants of survival.

Of 2,782 patients undergoing isolated coronary artery bypass grafting (CABG) from 1970 through 1979, 196 exhibited severe global impairment of left ventricular (LV) wall motion preoperatively (LV score, greater than or equal to 15; ejection fraction, less than 0.40 in all patients and less than 0.30 in 67%). The initial 89 patients (Group 1) underwent CABG without potassium chloride cardioplegia. The subsequent 107 patients (Group 2) were given potassium chloride cardioplegia intraoperatively. Group B patients received more grafts per patient (3.1 versus 2.5; p less than 0.001) and were completely revascularized more often (72.9% versus 58.4%; p less than 0.05). Operative mortality was lower in Group B (3.7% versus 12.4%; p less than 0.025), and 5-year cumulative survival was better in Group B (88.8% versus 63.9%; p less than 0.0001). Preoperative congestive heart failure resulted in higher operative mortality (14.3% versus 4.5%; p less than 0.05) and lower 5-year survival (65.0% versus 81.8%; p less than 0.02). Complete revascularization led to higher 5-year survival (82.2% versus 66.0%; p less than 0.02) but did not alter operative mortality significantly (6.9% versus 9.1%). Potassium chloride cardioplegia may influence operative survival favorably by reducing perioperative myocardial infarction in patients with severe LV dysfunction. Long-term survival relates to completeness of revascularization and severity of congestive heart failure as variables independent of methods of myocardial protection.

Coronary Artery Bypass↗
PubMed1984

Comparison of operative mortality and morbidity for initial and repeat coronary artery bypass grafting: The Coronary Artery Surgery Study (CASS) registry experience.

The National Heart, Lung, and Blood Institute's Coronary Artery Surgery Study (CASS) registry population was reviewed to allow comparison of operative mortality and morbidity rates for initial and repeat coronary artery bypass grafting (CABG) procedures. Standardized data collection was employed in CASS during patient entry (July 1, 1974, to May 31, 1979) and follow-up (ended November 30, 1982). Initial CABG was performed on 9,369 patients. Mean follow-up was 60.5 months. Repeat CABG was required in 283 patients (3.0%). The mean interval between operations was 39.3 months. Individuals needing reoperation tended to be young (p less than 0.0001) and female (p less than 0.002) and to have less extensive coronary artery disease (p less than or equal to 0.0001), less left ventricular impairment (p less than 0.0001), less evidence of congestive heart failure (p = 0.006), and fewer coronary vessel systems bypassed at the first operation (p less than 0.0001). Repeat CABG carried an increased risk of death compared with initial CABG (5.3% versus 3.1%, respectively; p less than 0.05). However, the rates of perioperative myocardial infarction (6.4% for repeat and 5.8% for initial CABG) and of all surgical complications combined (30.6% versus 27.9%) were not significantly different from those at initial CABG.

Adult↗
PubMed1984

Detrimental effect of perioperative myocardial infarction on late survival after coronary artery bypass. Report from the Coronary Artery Surgery Study--CASS.

The influence of perioperative myocardial infarction on late survival after coronary artery bypass grafting was reviewed in 9,777 patients who underwent operation between 1974 and 1979. Definite or probable perioperative myocardial infarction was diagnosed in 561 patients (5.7%). The incidence decreased from 6.6% in 1974 to 4.1% in 1979 (p less than 0.005). Actuarial survival, including hospital deaths, at 1, 3, and 5 years was significantly greater in patients without infarction than in patients with infarction (96%, 94%, and 90% versus 78%, 74%, and 69%; p less than 0.0001). The difference persisted among patients dismissed from the hospital. Reduction in late survival among patients with perioperative infarction was due to the poor outcome of those who had complications (5 year survival rates 40% overall and 73% for patients dismissed from the hospital). Multivariate analysis identified perioperative myocardial infarction as an important independent predictor of late survival after bypass grafting; it was surpassed only by left ventricular function (wall motion score), age, and number of associated medical diseases.

Coronary Artery Bypass↗
PubMed1983

Use of survival analysis to determine the clinical significance of new Q waves after coronary bypass surgery.

There are few data on the long-term effects of new Q waves on survival and morbidity after coronary bypass graft surgery (CABG). We followed 1340 patients who underwent CABG in 1978 at 10 hospitals participating in the Coronary Artery Surgery Study (CASS). The incidence of perioperative Q-wave infarction was 4.76% (range 0.0-10.3% by hospital). The rate of infarction was higher in patients who had an increased left ventricular end-diastolic pressure or cardiomegaly on the preoperative chest radiograph. Patients who received more grafts or who had longer cardiopulmonary bypass time were also at higher risk of infarction. In a stepwise discriminant analysis of 44 clinical, angiographic and surgical variables, cardiopulmonary bypass time, topical cardiac hypothermia and cardiomegaly entered the stepwise selection of variables. Long-term survival was adversely affected by the appearance of new postoperative Q waves. The hospital mortality was 9.7% in the 62 patients who had new postoperative Q waves and 1.0% in the 1278 patients who did not (p less than 0.001); the 3-year cumulative survival rates were 85% and 95%, respectively (p less than 0.001). In patients who survived to hospital discharge, the presence of new postoperative Q waves did not adversely affect 3-year survival (94% and 96%, respectively). The survival rates were worse in patients who had a history of infarction or who had impaired left ventricular function preoperatively. The number of readmissions to hospital after CABG among the patients who had a transmural perioperative infarction was similar to to that among patients who did not. We conclude that the appearance of new Q waves after CABG adversely affects survival. The major impact on mortality occurs before hospital discharge. Patients who are destined to have a perioperative infarct cannot be predicted from commonly measured preoperative and angiographic variables.

Adult↗
PubMed1983

Coronary arteriography and coronary artery bypass surgery: morbidity and mortality in patients ages 65 years or older. A report from the Coronary Artery Surgery Study.

Of 2144 patients age 65 years or older entered into the registry of the Coronary Artery Surgery Study (CASS) who had coronary arteriography, 1086 underwent isolated coronary artery bypass grafting. Complications of angiography included death in four patients and nonfatal myocardial infarction in 17. Eight patients suffered neurologic complications, which were transient in five. The perioperative mortality was 5.2% (57 of 1086), which is significantly greater than the perioperative mortality of 1.9% (151 of 7827) in patients younger than 65 years entered in CASS (p less than 0.001). There was a trend toward an increased mortality rate with age; it was 4.6% (37 of 803) in patients age 65-69 years, 6.6% (16 of 241) in those 70-74 years and 9.5% (four of 42) in those 75 years or older. The duration of hospital stay after operation was significantly longer for the patients 65 years or older than for the patients younger than 65 (13.3 vs 11.4 days; p less than 0.001). Stepwise linear discriminant analysis identified five variables predictive of perioperative mortality: presence of 70% or more stenosis of the left main coronary artery and a left-dominant circulation, left ventricular end-diastolic pressure, a history of current cigarette smoking, pulmonary rales on auscultation, and presence of one or more associated medical diseases. A second linear discriminant analysis, incorporating 7658 CASS patients who underwent isolated coronary artery bypass surgery irrespective of age, examined whether age 65 years or older was an independent predictor of perioperative mortality. The variables selected, in order of significance, were congestive cardiac failure score, left main coronary artery stenosis and a left-dominant circulation, age 65 years or older, left ventricular wall motion score, sex and history of unstable angina pectoris. In patients 65 years or older, the mortality from coronary arteriography is low, whereas mortality from coronary artery bypass surgery is greater than that in CASS patients younger than 65 years.

Aged↗
PubMed1983

Results of coronary artery surgery in patients with poor left ventricular function (CASS).

We identified 420 medically treated and 231 surgically treated patients (coronary graft plus myocardial surgery in 30%) who had severe left ventricular dysfunction manifest by an ejection fraction below 0.36 and markedly abnormal wall motion. Compared with medically treated patients, those treated surgically had more severe angina (56.7% vs 29.0% class III or IV; p less than .001), less heart failure as predominant symptom (11.1% vs 18.8%; p less than .003), more severe coronary disease (66.7% vs 50.2% three-vessel disease; p less than .001), a greater concentration of left main coronary artery lesions greater than 70% (12.6% vs 3.8%: p less than .001), and a greater estimated extent of jeopardized myocardium (p less than .001). Multivariate regression analysis of survival, which adjusts for the above covariates, showed that surgical treatment prolonged survival (p less than .05), although it ranked below severity of heart failure symptoms, age, ejection fraction, and left main stenosis greater than 70% in determining prognosis. Surgical benefit was most apparent for patients with ejection fractions below 0.26 who had a 43% 5 year survival with medical treatment vs 63% with surgery. Surgically treated patients experienced substantial symptomatic benefit compared with medically treated patients if their presenting symptoms were predominantly angina; however, there was no relief of symptoms caused primarily by heart failure. We conclude that patients with predominantly ischemic pain symptoms, despite poor left ventricular function, benefit from surgery; however, operative mortality in this high-risk subset must equal or better the 6.9% obtained in this study.

Actuarial Analysis↗
PubMed1983

Prognostic value of angiographic indices of coronary artery disease from the Coronary Artery Surgery Study (CASS).

The Coronary Artery Surgery Study, CASS, enrolled 24,959 patients between August 1975 and June 1979 who were studied angiographically for suspected coronary artery disease. This paper compares the prognostic value for survival without early elective surgery of eight different indices of the extent of coronary artery disease: the number of diseased vessels, two indices using the number of proximal arterial segments diseased, two empirically generated indices from the CASS data, and the published indices of Friesinger, Gensini, and the National Heart and Chest Hospital, London. All had considerable prognostic information. Typically 80% of the prognostic information in one index was also contained in another. Our analysis shows that good prediction from angiographic data results from a combination of left ventricular function and arteriographic extent of disease. Prognosis may reasonably be obtained from three simple indices: the number of vessels diseased, the number of proximal arterial segments diseased, and a left ventricular wall motion score. These three indices account for an estimated 84% of the prognostic information available. 6-yr survival varies between 93 and 16% depending upon the values of these three indices.

Angiography↗