Biomedical subjects

G T Christakis

Publications and source records attributed to G T Christakis.

At least 73 records · Page 4Linked to original sources

PubMed1989

The changing pattern of coronary artery bypass surgery.

Recent advances in interventional cardiology have altered the profile of patients referred for coronary artery bypass surgery. In recent years, the proportion of high-risk patients has increased dramatically. To evaluate the impact of the changing pattern of surgical patients, we prospectively followed up 7,334 patients who had coronary artery bypass surgery between 1982 and 1986. Multivariate analysis identified the following risk factors for operative mortality: urgency of surgery, left ventricular ejection fraction, age, female sex, previous bypass surgery, and left main coronary artery stenosis. Perioperative mortality has remained stable despite an increasing incidence of high-risk patients. However, perioperative morbidity has increased, due to the large number of high-risk patients. A multivariate analysis was performed by year to identify temporal trends in risk factors. Urgency of surgery, age, and previous bypass surgery have become more significant predictors of mortality with respect to time, whereas female sex, left ventricular ejection fraction, and left main coronary artery stenosis have become less significant determinants of mortality. Our results demonstrate the critical dependence of mortality and morbidity rates on the case mix, and further improvements in the results of coronary artery bypass surgery will require better strategies for the increasing number of high-risk patients.

Age Factors↗

PubMed1988

Decreased postoperative myocardial fatty acid oxidation.

Myocardial substrate preferences following cardioplegic arrest for coronary bypass surgery have not been established. Fatty acids are believed to be the major fuel source for aerobic metabolism. Following cardioplegic arrest arterial fatty acid levels are elevated and myocardial fatty acid accumulation without oxidation may contribute to reperfusion injury. Perioperative fatty acid metabolism was evaluated in 18 patients undergoing elective coronary bypass surgery who were randomized to receive either blood (n = 11) or crystalloid (n = 7) cardioplegia. Palmitate labeled with 14carbon was infused perioperatively and arterial and coronary sinus blood samples were obtained to calculate myocardial fatty acid extraction and oxidation before and after cardioplegic arrest. Lactate and glycerol were released from the heart during both blood and crystalloid cardioplegia, suggesting ischemic glycolysis and lipolysis. Myocardial oxygen consumption was depressed and the myocardial consumptions of lactate, glucose, and fatty acids were minimal during the first 60 min after aortic clamp removal in both groups despite high arterial concentrations. Fatty acid oxidation was minimal after blood cardioplegia and was not found after crystalloid cardioplegia. Fatty acids were extracted by the heart, but were not aerobically metabolized following cardioplegic arrest. Myocardial fatty acid accumulation without oxidation may have been deleterious. The inability of the heart to oxidize exogenous fatty acids may reflect altered myocardial exogenous substrate preferences during reperfusion following coronary bypass surgery.

Cardioplegic Solutions↗

PubMed1988

Right and left ventricular metabolites.

Current methods of cardioplegic delivery may delay the recovery of right ventricular metabolism and function. To evaluate right and left ventricular metabolism, we performed biopsies in 37 patients undergoing elective coronary bypass operation with aortic root blood cardioplegia. Right ventricular temperatures were warmer than left ventricular temperatures during cardioplegic arrest (right ventricle: 16.8 degrees +/- 3.8 degrees C, left ventricle: 14.3 degrees +/- 3.7 degrees C, p = 0.02). Adenosine triphosphate concentrations were lower in the right ventricle than in the left ventricle before cardioplegic arrest (right ventricle: 13.8 +/- 7.8 mmol/kg, left ventricle: 21.5 +/- 8.7 mmol/kg, p = 0.02). After reperfusion, right ventricular adenosine triphosphate concentrations fell to low levels (10 +/- 6 mmol/kg). Postoperative left and right ventricular high energy phosphate concentrations (the sum of adenosine triphosphate and creatine phosphate levels) correlated inversely with myocardial temperatures during cardioplegia (r = -0.29, p = 0.048). Aortic root cardioplegia did not cool the right ventricle as well as it did the left ventricle. The lower preoperative high energy phosphate concentrations may have increased the susceptibility of the right ventricle to ischemic injury. Alternative methods of myocardial preservation may improve right ventricular cooling and protection.

Adenosine Triphosphate↗

PubMed1988

Dipyridamole preserved platelets and reduced blood loss after cardiopulmonary bypass.

Cardiopulmonary bypass activates and depletes platelets, which may contribute to postoperative bleeding. In addition, activated platelets may be deposited in the coronary vasculature after ischemia and cardioplegia, which may delay recovery of cardiac function and metabolism and may contribute to early bypass graft occlusion. The antiplatelet agent dipyridamole reduces platelet activation and depletion and may decrease postoperative bleeding and transfusion requirements. A prospective randomized trial was conducted in 58 patients undergoing elective coronary bypass operations to compare the effects of oral (19 patients) and intravenous (21 patients) dipyridamole to the results obtained in a control group (18 patients) who received no dipyridamole. Preoperative oral administration of dipyridamole resulted in lower plasma drug concentrations in the early postoperative period than perioperative intravenous administration (p = 0.0001 by analysis of variance). Postoperative arterial platelet counts were highest in the patients receiving intravenous dipyridamole, intermediate in those receiving oral dipyridamole, and lowest in the control group (p = 0.03 by analysis of variance). Postoperative blood loss and blood product transfusions were significantly reduced with both oral and intravenous dipyridamole (p = 0.04 by analysis of variance). Dipyridamole preserved platelets and reduced postoperative bleeding. Intravenous dipyridamole resulted in higher platelet counts than oral dipyridamole and may be required to reduce postoperative bleeding in high-risk patients.

Administration, Oral↗

PubMed1988

Predictors of operative survival after valve replacement.

To identify the independent predictors of operative mortality, we examined 31 preoperative clinical and hemodynamic variables in 2,488 patients undergoing valvular surgery between 1982 and 1986. The operative mortality was 5.3% in 1,098 patients after aortic valve surgery, 6.6% in 1,107 after mitral valve surgery, and 10.1% in 283 after double valve surgery. Multivariate statistical analysis demonstrated that urgent surgery, endocarditis requiring urgent surgery, previous aortic valve surgery, coronary artery disease, and age were independent risk factors for aortic valve surgery. Urgent surgery, endocarditis, age, coronary artery disease, and preoperative ventricular ejection fraction were independent predictors of mortality after mitral valve surgery. The predictors of mortality after double valve surgery were urgent surgery, age, preoperative ventricular ejection fraction, and tricuspid valve disease. Gender and the type of valvular lesion, procedure, and prosthesis did not independently influence operative mortality. Strategies to diminish operative mortality should include careful assessment of the risks and benefits in elderly patients, early operative intervention before deterioration that necessitates urgent surgery, and use of improved techniques of myocardial protection in high-risk subgroups.

Adult↗

PubMed1987

Dipyridamole reduced myocardial platelet and leukocyte deposition following ischemia and cardioplegia.

Urgent coronary revascularization for acute myocardial ischemia results in an increased mortality and morbidity. Deposition of activated platelets and leukocytes into the ischemic myocardium during reperfusion may augment perioperative ischemic injury. Dipyridamole reduces platelet activation and may reduce myocardial deposition and prevent ischemic injury during reperfusion. The effects of dipyridamole on myocardial platelet and leukocyte deposition were evaluated in a canine model of acute regional myocardial ischemia with reperfusion during cardioplegia on cardiopulmonary bypass. Eight dogs underwent left anterior descending (LAD) coronary artery ligation for 45 min followed by cardiopulmonary bypass and release of the ligature during 60 min of cold crystalloid cardioplegic arrest to simulate urgent revascularization. Four dogs were randomized to receive an infusion of dipyridamole perioperatively (50 mg/hr) and 4 dogs served as controls. Autologous platelets were labeled with 111In, leukocytes with 99mTc, and erythrocytes with 51Cr. The labeled cells were infused immediately after cross-clamp release and myocardial biopsies were obtained at 10, 20, 30, and 60 min of reperfusion. Platelets were deposited in the myocardium during reperfusion and four times more platelets were found in the LAD region than the circumflex region. Leukocyte deposition was similar in the LAD and circumflex regions. Dipyridamole reduced both platelet and leukocyte deposition and the reduction was greater in the LAD than in the circumflex region. Myocardial platelet and leukocyte deposition was found after regional ischemia, cardioplegia, and cardiopulmonary bypass. Dipyridamole reduced myocardial platelet and leukocyte deposition and may reduce perioperative ischemic injury.

Animals↗

PubMed1987

Right ventricular function: a comparison between blood and crystalloid cardioplegia.

Blood cardioplegia resulted in better left ventricular (LV) function than crystalloid cardioplegia after elective coronary artery bypass operations. However, most methods of cardioplegic delivery may not adequately cool and protect the right ventricle, and right ventricular (RV) dysfunction may limit hemodynamic recovery. Therefore, RV and LV temperatures were measured intraoperatively and RV and LV function were evaluated postoperatively in 80 patients with double-vessel or triple-vessel coronary artery disease who were randomized to receive either blood cardioplegia or crystalloid cardioplegia. Myocardial performance, systolic function, and diastolic function were assessed with nuclear ventriculography by evaluating the response to volume loading. Preoperatively the groups were similar. Intraoperatively, blood cardioplegia resulted in significantly warmer LV and RV temperatures (left ventricle: 15.5 degrees +/- 0.2 degrees C with blood cardioplegia and 12.6 degrees +/- 0.3 degrees C with crystalloid cardioplegia [p less than .0001]; right ventricle: 18.3 degrees +/- 0.3 degrees C with blood cardioplegia and 15.1 degrees +/- 0.3 degrees C with crystalloid cardioplegia [p less than .0001]). Postoperatively, blood cardioplegia resulted in better LV performance (higher LV stroke work index at a similar LV end-diastolic volume index [EDVI]) (p = .01), better LV systolic function (similar systolic blood pressures at smaller LV end-systolic volume indexes [ESVI]), (p = .04), and improved LV diastolic function (lower left atrial pressures at similar LVEDVIs) (p = .03).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

PubMed1987

Blood conservation with membrane oxygenators and dipyridamole.

Cardiopulmonary bypass induces platelet activation and dysfunction, which result in platelet deposition and depletion. Reduced platelet numbers and abnormal platelet function may contribute to postoperative bleeding. A membrane oxygenator may preserve platelets and reduce bleeding more than a bubble oxygenator, and the antiplatelet agent dipyridamole may protect platelets intraoperatively and reduce bleeding postoperatively. A prospective randomized trial was performed in 44 patients undergoing elective coronary artery bypass grafting to assess the effects of the membrane oxygenator and dipyridamole on platelet counts, platelet activation products, and postoperative bleeding. Patients who were randomized to receive a bubble oxygenator and no dipyridamole had the lowest postoperative platelet counts, the greatest blood loss, and the most blood products transfused. Platelet counts were highest and blood loss was least in patients randomized to receive a membrane oxygenator and dipyridamole (p less than .05). A bubble oxygenator with dipyridamole and a membrane oxygenator without dipyridamole resulted in intermediate postoperative platelet counts and blood loss. Arterial thromboxane B2 and platelet factor 4 concentrations were elevated on cardiopulmonary bypass in all groups. Both the membrane oxygenator and dipyridamole were independently effective (by multivariate analysis) in preserving platelets. Optimal blood conservation was achieved with a membrane oxygenator and dipyridamole.

6-Ketoprostaglandin F1 alpha↗

PubMed1987

The determinants of mortality and morbidity after multiple-valve operations.

The factors predictive of hospital mortality and morbidity after contemporary multiple-valve surgical procedures were identified to develop strategies to improve the results of such procedures. Preoperative, intraoperative, and postoperative information was collected prospectively on 90 consecutive patients undergoing surgical procedures between 1982 and 1984. The operative mortality was 5.6%, and the incidence of postoperative low-output syndrome was 16.7%. Multivariate logistic regression analysis identified tricuspid regurgitation (p less than .03, improvement-of-fit chi square) and the aortic valve lesion (p less than .03) as the independent predictors of postoperative complications (mortality or low-output syndrome). Patients with tricuspid regurgitation and right ventricular decompensation and those with aortic stenosis and left ventricular hypertrophy had limited ventricular functional reserve and faced an increased risk. Improved methods of myocardial protection may reduce the risk in these patients.

Adult↗

PubMed1987

Atrial activity during cardioplegia and postoperative arrhythmias.

Cardioplegia provides excellent protection for the left ventricle, but the right atrium may be poorly protected. Myocardial temperatures, right atrial electrical activity, and postoperative arrhythmias were assessed in 103 patients participating in two consecutive randomized trials comparing blood cardioplegia (n = 36), crystalloid cardioplegia (n = 38), and diltiazem crystalloid cardioplegia (n = 29). Both right atrial and right ventricular temperatures were significantly warmer (p less than 0.05) during delivery of the blood cardioplegic solution than during delivery of either the crystalloid or the diltiazem crystalloid cardioplegic solutions; the aortic root temperatures were 9 degrees +/- 2 degrees C with blood cardioplegia and 5 degrees + 1 degrees C with both crystalloid and diltiazem crystalloid cardioplegia. Atrial activity during cardioplegic arrest was greatest with blood cardioplegia (12 +/- 3 beats/min), lower with crystalloid cardioplegia (10 +/- 2 beats/min), and minimal with diltiazem crystalloid cardioplegia (5 +/- 1 beats/min, p less than 0.05). Perioperative ischemic injury (by creatine kinase MB isoenzyme analysis) was greatest with crystalloid cardioplegia (p less than 0.05). Postoperative supraventricular arrhythmias (both treated and untreated) were more frequent after crystalloid cardioplegia (crystalloid, 63%; blood, 40%; diltiazem, 47%; p less than 0.05). Patients in whom supraventricular arrhythmias developed had significantly more postoperative ischemic injury (by creatinine kinase MB isoenzyme analysis, p less than 0.05). Blood cardioplegia reduced supraventricular arrhythmias by reducing ischemic injury despite warmer intraoperative temperatures and more right atrial activity. Diltiazem crystalloid cardioplegia reduced postoperative arrhythmias by improving intraoperative myocardial protection and suppressing intraoperative and postoperative atrial activity. Crystalloid cardioplegia cooled but did not arrest the right atrium intraoperatively, resulted in the most perioperative ischemic injury, and yielded the highest incidence of postoperative supraventricular arrhythmias.

Arrhythmias, Cardiac↗

PubMed1987

Increased risk of urgent revascularization.

To determine the risk factors for operative mortality and morbidity, we performed a prospective analysis of 1,980 patients undergoing isolated coronary artery bypass operations between 1982 and 1984. The operative mortality was 3.5%, and the incidence of perioperative myocardial infarction was 8.6% and low output syndrome, 12.0%. Stepwise logistic regression identified sex, preoperative left ventricular ejection fraction, and the urgency of operation as independent risk factors for postoperative mortality. Urgent revascularization was performed in patients with unstable angina refractory to maximal medical therapy. In these patients the operative mortality was 8.5%. Independent risk factors of postoperative morbidity, in addition to sex, ejection fraction, and urgent revascularization, included a previous bypass procedure, age, and New York Heart Association functional class. Unstable angina unresponsive to medical therapy contributed significantly to the operative risk. Interventions to reduce perioperative ischemic injury, such as improved methods of myocardial protection, may improve the results in high-risk patients.

Cardiac Output, Low↗

PubMed1987

Transient biventricular dysfunction following coronary bypass surgery with potassium cardioplegia.

Although myocardial revascularization relieves anginal symptoms, the effect on ventricular function remains controversial. Sixty-six patients undergoing elective coronary bypass surgery with normal right and left ventricular function were studied 1 month preoperatively (PRE), 3-5 hours perioperatively (PERI) and 3-5 months postoperatively (POST). Nuclear ventriculograms were employed to calculate right and left ventricular ejection fractions (RVEF, LVEF), end diastolic volume indices (RVEDVI, LVEDVI) and end systolic volume indices (RVESVI, LVESVI). Cardiac index (CI), stroke index (SI) and an approximation of left ventricular stroke work index (LVSWI) were also calculated from the scintigraphic data. Right and left ventricular ejection fractions were lower perioperatively (PRE:RVEF 37 +/- 2.5, LVEF 61 +/- 3; PERI:RVEF 32 +/- 3, LVEF 51 +/- 4; POST:RVEF 35 +/- 3, LVEF 56 +/- 4%, p less than 0.01 by analysis of variance, ANOVA) despite lower end diastolic volume indices perioperatively, (p less than 0.05 by ANOVA). The ratio of systolic blood pressure to LVESVI was significantly lower PERI than PRE or POST, (p less than 0.01 by ANOVA). SI, LVSWI, LVEF and RVEF were lower perioperatively at any level of LVEDVI or RVEDVI (p less than 0.01 by paired analyses of covariance), suggesting transient depression of right and left ventricular performance perioperatively. Right ventricular recovery was incomplete 4 months postoperatively. The patients were able to exercise longer at higher workloads postoperatively (p less than 0.01 by ANOVA). Chest pain resulted in discontinuation of exercise in 57% of patients PRE but only 5% POST (p less than 0.01), even though all patients were receiving full medical therapy preoperatively and no therapy postoperatively. Myocardial revascularization provided symptomatic relief and increased work capacity. However, right and left ventricular function were transiently depressed in the early perioperative period.

Coronary Artery Bypass↗

PubMed1987

Cardiac release of prostacyclin and thromboxane A2 during coronary revascularization.

Cardiac surgery stimulates the systemic synthesis of prostacyclin and thromboxane A2, but the cardiac release of these prostanoids has been reported infrequently. Fifty-four patients undergoing elective coronary artery bypass had coronary sinus catheters inserted to evaluate the cardiac release of the stable metabolites of prostacyclin (6-keto-prostaglandin F1 alpha) and thromboxane A2 (thromboxane B2). Arterial concentrations of 6-keto-prostaglandin F1 alpha and thromboxane B2 were elevated after cardiac cannulation and during cardiopulmonary bypass. The cardiac release of 6-keto-prostaglandin F1 alpha was observed after cannulation and during, but not after, cardiopulmonary bypass. Cardiac thromboxane B2 release was detected after cross-clamp release and persisted during the early postoperative period when cardiac 6-keto-prostaglandin F1 alpha release was no longer detectable. Cardiopulmonary bypass stimulated the systemic production of thromboxane and prostacyclin. The cardiac release of thromboxane was unopposed by cardiac prostacyclin production in the early postoperative period and may contribute to reperfusion injury.

6-Ketoprostaglandin F1 alpha↗

PubMed1986

Late postoperative ventricular function after blood and crystalloid cardioplegia.

Although blood cardioplegia preserves perioperative ventricular function better than crystalloid cardioplegia, late results are uncertain. Nuclear ventriculograms were used to assess ventricular function in 47 patients undergoing coronary bypass surgery who were randomly assigned to receive blood (23 patients) or crystalloid cardioplegia (24 patients). Data were acquired at rest and during maximal exercise (bicycle ergometer) 1 month before surgery (PRE), 5 months after surgery (POST), and perioperatively at rest 3 to 5 hr after operation (PERI). Perioperatively, blood cardioplegia decreased ischemic injury (less elevation in creatine kinase-MB fraction and aspartate aminotransferase; p less than .05), preserved ventricular performance (lower stroke work index at higher left ventricular end-diastolic volume index after crystalloid than blood cardioplegia; p = .02 by analysis of covariance [ANOCOVA]) and preserved systolic function (higher left ventricular end-systolic volume index [LVESVI] at similar systolic blood pressure after crystalloid than blood cardioplegia; p = .02 by ANOCOVA). Postoperatively, resting ventricular performance and systolic function were not different with blood and crystalloid cardioplegia and were similar to preoperative measurements. Postoperatively, the response to exercise was similar between the two groups and was improved compared with that at PRE. Postoperative systolic function at exercise was similar between the two groups but was better than that at PRE (higher systolic blood pressure at similar LVESVI; p = .01 by ANOCOVA). The type of cardioplegic solution influenced perioperative but not late postoperative function after elective coronary artery bypass surgery.

Blood↗

PubMed1986

Reducing the risk of urgent revascularization for unstable angina: a randomized clinical trial.

A prospective, randomized trial was instituted to determine whether blood cardioplegia (BC) could reduce the morbidity and mortality for patients undergoing urgent coronary bypass for unstable angina. One hundred forty patients who came to the hospital with prolonged angina at rest and who required urgent revascularization because their symptoms were resistant to medical therapy were randomized to receive BC (n = 70) or crystalloid cardioplegia (CC) (n = 70). The operative mortality rate was 2.8%, the incidence of myocardial infarction was 8.6%, the incidence of low output syndrome was 18% and morbidity (myocardial infraction or low output syndrome) was 23%. Patients who received BC had a significantly lower mortality rate (BC, 0%; CC, 5%; p less than 0.05) and incidence of myocardial infarction (BC, 4%; CC, 13.5%; p less than 0.05) or low output syndrome (BC, 10%; CC, 19%; p less than 0.05). The highest postoperative CK-MB level was less after BC (BC, 31 +/- 17 U/L; CC, 56 +/- 13 U/L; p less than 0.05). Preoperative predictors of postoperative morbidity in addition to the type of cardioplegia included the response to medical therapy, persistent ischemic electrocardiographic changes, left ventricular ejection fraction, and age. A multivariate analysis identified the type of cardioplegic protection (p = 0.008) and age (p = 0.05) as significant independent predictors of postoperative morbidity. BC reduced the risk of urgent revascularization for unstable angina.

Age Factors↗

PubMed1986

Diltiazem cardioplegia. A balance of risk and benefit.

Calcium channel blockers may prevent myocardial injury during cardioplegia and reperfusion. A prospective, randomized trial was instituted to evaluate the hemodynamic and myocardial metabolic recovery in 40 patients undergoing elective aorta-coronary bypass with either diltiazem in crystalloid potassium cardioplegia (n = 20) or crystalloid potassium cardioplegia (n = 20). In a preliminary trial, doses between 150 and 250 micrograms/kg reduced the period of heart block after cross-clamp removal (90 +/- 110 minutes) from that found with higher doses and improved myocardial metabolism. In the randomized trial, diltiazem cardioplegia (150 micrograms/kg) produced coronary vasodilatation during cardioplegia and produced less reactive hyperemia during reperfusion. Myocardial oxygen extraction was lower and myocardial lactate production was less after diltiazem cardioplegia during reperfusion. Tissue adenosine triphosphate and creatine phosphate concentrations were preserved better after diltiazem cardioplegia. The postoperative creatine kinase MB levels were less (p less than 0.05) after diltiazem cardioplegia, which indicated less myocardial injury. Postoperative volume loading demonstrated that systolic function (the relation between systolic blood pressure and end-systolic volume index) was depressed after diltiazem cardioplegia compared to crystalloid cardioplegia, but cardiac index was higher because afterload (mean arterial pressure) was lower and preload (end-diastolic volume index) was higher. Diltiazem cardioplegia preserved high-energy phosphates, improved postoperative myocardial metabolism, and reduced ischemic injury after elective coronary bypass. However, diltiazem was a potent negative inotrope and produced prolonged periods of electromechanical arrest. Diltiazem cardioplegia may be of value in patients with severe ischemia but should be used with caution in patients with ventricular dysfunction, and a dose-response relation must be established at each institution before clinical use.

Benzazepines↗

PubMed1986

Accelerated myocardial metabolic recovery with terminal warm blood cardioplegia.

Although blood cardioplegia provides excellent protection, myocardial metabolic recovery is delayed. To evaluate the benefits of a terminal warm cardioplegic infusion after cold blood cardioplegia, we performed a prospective randomized trial in 20 patients undergoing elective coronary bypass grafting. Eleven patients received cold blood cardioplegia and nine patients received cold blood cardioplegia and warm blood cardioplegia before cross-clamp removal (hot shot). The hot shot provided oxygen and removed excess lactate from the arrested heart. After the hot shot lactate was extracted by the heart and tissue adenosine triphosphate and glycogen concentrations were preserved. Atrial pacing and volume loading 3 and 4 hours postoperatively decreased myocardial lactate extraction after cold blood cardioplegia but increased lactate extraction after the hot shot. Left atrial pressures were higher at similar end-diastolic volumes (by nuclear ventriculography), which suggested decreased diastolic compliance after cold blood cardioplegia. Terminal warm blood cardioplegia accelerated myocardial metabolic recovery, preserved high-energy phosphates, improved the metabolic response to postoperative hemodynamic stresses, and reduced left atrial pressures.

Adenosine Triphosphate↗

PubMed1986

Can the results of contemporary aortic valve replacement be improved?

Although the results of contemporary aortic valve replacement are excellent, cardiac surgeons must identify the factors that predict postoperative morbidity and mortality to develop alternative strategies for high-risk patients. Two hundred seventy-seven consecutive patients undergoing isolated aortic valve replacement between 1982 and 1984 were evaluated. Thirty-seven clinical and 13 preoperative hemodynamic variables were analyzed by univariate and multivariate statistics to determine the risk factors for postoperative morbidity and mortality. The operative mortality was 3%, the incidence of a postoperative low output syndrome was 12%, and the incidence of a perioperative myocardial infarction was 5%. A multivariate, logistic regression analysis found that age was the only the only independent predictor of mortality. Three factors independently predicted postoperative low output syndrome: age, the presence of coronary artery disease, and the peak systolic gradient in patients with aortic stenosis. Patients with aortic stenosis had a higher incidence of postoperative ventricular dysfunction (17%) than those with mixed valvular disease (9%) or aortic regurgitation (5%). Perioperative myocardial infarction was predicted by the extent of coronary artery disease. The incidence of perioperative myocardial infarction was higher in patients with triple-vessel coronary artery disease (13%) and those with left main stenosis (18%) than in patients with single- or double-vessel disease (4%) or those without coronary artery disease (4%). Because of the higher risk of aortic valve replacement in older patients, the risk-benefit ratio of the operation must be carefully assessed in the elderly. Improved methods of myocardial protection may reduce the risks for patients with aortic stenosis and symptomatic triple-vessel coronary artery disease.

Adult↗