There were 53 men and 107 women with mean age of 60.5±19.1 yr (range, 32-75 yr). The majority of patients were in NYHA functional class III or IV. Thirty two patients (20%) had undergone previous cardiac surgery. One hundred fifty-four patients (96%) were operated on electively, and 6 patients (4%) were operated on urgently. The complete clinical profile of the patients is summarized in Table 1. Choice of the prosthesis was determined on the basis of the patient's age, special request, and comorbid factors. In the aortic position, 137 mechanical and 20 bioprosthetic valves were implanted. The majority of mechanical prostheses included the St. Jude (St. Jude Medical Inc, Minneapolis, MN, U.S.A.) (n=66), Carbomedics (Carbomedics Inc, Austin, TX, U.S.A.) (n=24), and Omniscience (Medical CV Inc, Inner Grove Heights, MN, U.S.A.) (n=19) valves. Besides, Sorin (Sorin Biomedical, Saluggia, Italy) (n=9), Edwards Mira (Edwards Lifesciences, Irvine, CA, U.S.A.) (n=9), and other mechanical valve (n=10) were used. The type of bioprosthesis was the Carpentier-Edward pericardial valve (Edwards Lifesciences) (n=16) and Hancock II porcine valve (Medtronics Inc, Minneapolis, MN, U.S.A.) (n=4). Similarly, 137 mechanical and 20 bioprosthetic valves were implanted in the mitral position, including the St. Jude (n=61), Carbomedics (n=24), Omniscience (n=20), Mira (n=11), Sorin (n=10), and other mechanical valve (n=11). The type of bioprosthesis was the Carpentier-Edward pericardial valve (Edwards Lifesciences) (n=14) and Hancock II porcine valve (Medtronics Inc.) (n=6). Only 12 valves were implanted in the tricuspid valve position, and they included 5 mechanical and 7 bioprosthetic valves: St. Jude (n=3), Carbomedics (n=1), Edwards Mira (Edwards Lifesciences) (n=1), Hancock II (n=5), and Carpentier-Edward pericardial valve (n=2).

The most common aortic valve and mitral valve disorder was rheumatic valve disease, followed by prosthetic valve dysfunction. In contrast, the most common tricuspid valve disease was functional regurgitation secondary to left heart disease, followed by rheumatic valve disease. The complete list of valve disease presentation and pathologic diagnosis is presented in Table 2.

Intraoperative transesophageal echocardiography was performed in all patients to assess the extent and severity of valve disease and the quality of the replacement or repair postoperatively. All procedures were done through a median sternotomy. Valve operations were performed under the usual methods of cardiopulmonary bypass with a single aortic cross-clamp technique. Myocardial protection strategies usually included antegrade cardioplegia introduced directly into the coronary ostia and retrograde cardioplegia through a coronary sinus cannula. Moderate hypothermia was used, and the core temperature was allowed to drift to 28℃ to 32℃. Improved protection of the ventricles was provided by topical hypothermia with saline ice slush. A Biomedicus biopump (Medtronic) has been used in all patients since 1992. Distal coronary anastomoses were performed first, followed by the valve procedures. After excision of the aortic valve, the mitral valve was approached, usually through the interatrial groove, and was assessed for possible repair versus replacement. If mitral annular reconstruction was needed in the case of extensive calcification, it was performed with the utilization of glutaraldehyde-fixed bovine pericardium before implantation of the prosthesis. After the mitral valve procedure, the aortic valve was replaced (or infrequently repaired). Then tricuspid valve repair was performed with either a modified De Vega technique or Kay technique or with an annuloplasty ring. Less frequently, the tricuspid valve was replaced. Finally the proximal coronary anastomoses were performed. The operative data are listed in Table 3.

In the postoperative period, anticoagulation with warfarin was initiated for all patients if there was no evidence of active bleeding. Target international normalized ratio (INR) was 2.5-3.0 in all patients. When triple bioprosthesis were implanted, anticoagulation was just recommended in the first 6 months postoperatively for patients without atrial fibrillation.

Late outcomes were determined from clinical records when available or from written correspondence with patients' physicians and direct patient contact with telephone interviews when necessary. All follow-up data were collected by our research personnel and 7 patients were lost to follow-up. The mean and median follow-up was 5.7±5.2 and 6.3 yr, ranged from 1 month to 16 yr. Echocardiographic data at latest follow-up were collected by contacting referring cardiologists.

Statistical analysis was performed with SPSS software 10.0 (SPSS Inc, Chicago, IL, U.S.A.). Descriptive statistics are reported as mean±standard deviation for continuous variables and as frequencies and percentages for categorical variables. Unrelated two-group comparisons were done with unpaired, two-tailed Student's t tests for continuous variables and chi-square or Fisher's exact test for categorical data. Predictors of perioperative mortality were identified using univariable and multivariable logistic regression analysis. Long-term survival and freedom from morbid events were estimated using the Kaplan-Meier method. Cox regression was used to determine the independent predictors of late outcomes. The appropriateness of variable transformations was determined by means of univariate analysis. Variables with a univariate P value of less than 0.05 or those with known biologic significance, but failing to meet this critical chi-square level, were submitted to multivariable models.

The hospital mortality was 6.9% (11 patients). Five patients died due to multiorgan failure and sepsis, three due to postoperative stroke, two due to low cardiac output, and one due to sudden cardiac arrest. In the postoperative period, the incidence of complications was 28.8% (n=46 patients, in some patients there were more than one complication). Twelve patients (7.5%) required reexploration of the mediastinum for bleeding, and 11 (6.9%) required placement of a permanent pacemaker for heart block. Other morbidities included stroke in 10 patients (6.3%), renal insuffiency in 8 patients (5%, Cr ≥2.0 mg/dL), tamponade in 6 patients (3.8%), pulmonary complications (included pneumonia, atelectasis, and pleural effusions) in 5 patients (3.1%), sternal infection in 5 patients (3.1%), and sepsis in 2 patients (1.3%). Univariate analysis revealed the following variables to be associated with increased operative mortality: old age (P=0.003), preoperative renal failure (P=0.004), postoperative pulmonary complications (P=0.038), postoperative renal failure (P<0.001), and postoperative stroke (P<0.001). Postoperative renal failure (P<0.001, OR=44.6, 95% CI 6.3-316.1) and postoperative stroke (P=0.01, OR=13.6, 95% CI 1.85-100.71) remained significant on multivariable analysis (Table 4).

During the follow-up period, an additional 12 patients died (8.1%), with 10 of them of cardiac origin: congestive heart failure (n=3), arrhythmia (n=3), prosthetic valve endocarditis (It was occurred during follow-up, n=2), acute myocardial infarction (n=1), and anticoagulation related hemorrhage (n=1). The other 2 deaths were due to noncardiac causes.

Univariate and multivariate analysis revealed only prosthetic valve endocarditis as significant (P=0.017, 0.011 respectively, OR=27.60 95% CI 2.16-352.21). Otherwise, neither tricuspid valve replacement nor reoperation were statistically associated with late mortality (Table 5).

Five-year and 10-yr survival was 86.9±3.0% and 83.9±3.6%, respectively, as illustrated in Fig. 1. Ten-year freedom from prosthetic valve endocarditis was 96.6±2.0% (Fig. 2). Ten-year freedom from thromboembolism was 89.3±3.4%, whereas 10-yr freedom from anticoagulation related hemorrhage was 82.4±4.3% (Fig. 2). Ten-year freedom from other valve-related morbidities, such as structural valve deterioration, valve thrombosis, and paravalvular leakage was 88.7±3.9%, 96.0±2.4%, and 97.8±1.5%, respectively.

Twenty patients required late reoperation. Ten-year freedom from reoperation was 84.3±4.3% (Fig. 2). The causes for reoperation were as follows: pannus formation (n=9), paravalvular leakage of mitral valve (n=4), mitral valve thrombosis (n=2), failure of tricuspid valve repair (n=2), failure of aortic valve and/or mitral valve repair (n=2), prosthetic valve dysfunction after double valve replacement (n=1), acute thrombosis of aortic valve (n=1), and prosthetic valve endocarditis (n=1).

On the latest follow-up, 130 patients were alive. Among them, 17 (13.1%) were in NYHA class I, 102 (78.5%) in class II, and 11 (8.5%) in class III. All but three of the patients had normally functioning prosthetic valves at the latest echocardiographic study. Three patients are thought to be reoperated in the future: structural valve deterioration (n=2), and prosthetic valve endocarditis (n=1).