Aortic valve replacement with a small prosthesis.

A small aortic prosthesis can be inserted in selected patients with excellent symptomatic improvement. A prospective evaluation was performed on 321 consecutive patients undergoing isolated aortic valve replacement between January 1982 and December 1984. Smaller prostheses (19 or 21 mm, predominantly pericardial valves, 132 patients) were inserted in older patients (p = .0001), women (p = .0001), smaller patients (body surface area: p = .0001), and patients with aortic stenosis (p = .0001). Twelve patients died in-hospital (3.7%) and 33 died during the follow-up period, producing an actuarial survival of 80% +/- 4% at 48 months. Survival was independently predicted by advancing age (p = .009), the preoperative NYHA functional class (p = .04) but not valve size (p = .28). Eighty-nine percent of patients were NYHA class I or II postoperatively compared with 22% preoperatively. Symptomatic recovery was similar for those with smaller size valves. Postoperative Doppler echocardiography in 57 patients revealed significant differences in aortic valve areas and gradients between the valve sizes. The 19 mm pericardial valves had the smallest areas (1.0 +/- 0.3 cm2) and the highest gradients (34 +/- 20 mm Hg). The aortic valve gradient was significantly related to cardiac output and valve size (p = .0001 by analysis of covariance). Linear regression analyses were used to estimate the aortic valve gradient during exercise (a 50% increase in cardiac output). The estimated exercise gradient was disturbingly high for the 19 mm valves (55 +/- 16 mm Hg), but the estimated exercise gradients for the 21, 23, and 25 mm valves were similar, all below 30 mm Hg. Aortic valve replacement with a small prosthesis resulted in excellent symptomatic improvement and acceptable resting valve gradients. However, a 19 mm prosthesis may produce prohibitive gradients during exercise, which may limit symptomatic recovery and should be avoided in active patients.

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.

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.

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.

Comparison between antibiotic irrigation and mobilization of pectoral muscle flaps in treatment of deep sternal infections.

Between January of 1978 and December of 1983, 41 patients developed deep sternal infections with mediastinitis after cardiac operations. Between January of 1978 and December of 1981, 19 of these patients were treated with débridement, primary wound closure, and mediastinal antibiotic irrigation (Group I). Between January of 1982 and December of 1983, 22 patients were treated with débridement, open "clean" packing, and delayed wound closure by the technique of pectoral muscle flap mobilization, which preserves the thoracoacromial pedicles and the pectoral humeral attachments (Group II). The purpose of this study was to compare the results of the treatment of deep sternal infections after cardiac operations with these two techniques. The perioperative hemodynamic, operation, functional, and pathological profiles of both groups of patients were the same. The cosmetic and functional results were the same in both groups as were shoulder girdle and torso mobility. We conclude that either technique is equally effective in the management of patients in whom the serious complication of deep sternal infection with mediastinitis develops after cardiac operation, and we now recommend débridement and pectoral muscle flap closure in one stage.

Morbidity and mortality in mitral valve surgery.

To develop strategies for the management of high-risk patients, contemporary risk factors for operative mortality and postoperative ventricular dysfunction were identified in 214 patients undergoing mitral valve surgery in 1982 and 1983. Thirty-eight preoperative and perioperative variables were prospectively collected and analyzed by univariate and multivariate statistics. The overall mortality was 4.6% and the incidence of postoperative low-output syndrome (LOS) was 18.7%. Forty-seven patients with coronary artery disease (CAD) had a higher mortality and incidence of LOS (as evidenced by the need for inotropic drugs or counterpulsation to maintain blood pressure) (those with CAD 15% mortality, 40% LOS; those without CAD 2% mortality, 13% LOS; p less than .05). The presence of unstable angina and ischemic mitral regurgitation further increased the risk. Age was also a predictor of outcome. Patients who died or had LOS were older (those who died, 65 +/- 7 years, those with LOS, 58 +/- 11 years) than patients who survived and did not have postoperative dysfunction (those who survived, 53 +/- 11; those with no LOS, 53 +/- 11; p less than .01). Mitral regurgitation was associated with a higher (p less than .05) mortality and incidence of LOS (mortality 10.5%, LOS 36%; n = 76) than was mitral stenosis (mortality 0%, LOS 4%; n = 74) or mixed lesions (mortality 3%, LOS 15%; n = 64). In patients without CAD, mitral regurgitation remained a significant predictor of mortality and ventricular dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)