Aortic valve replacement without myocardial revascularization

Aortic Valve Replacement for Aortic Stenosis and Concomitant Coronary Artery Bypass: Long-term Outcomes and Predictors of Mortality

Background

We evaluated the surgical results and predictors of long-term survival in patients who underwent coronary artery bypass grafting (CABG) at the time of an aortic valve replacement (AVR) due to aortic stenosis.

Materials and Methods

Between January 1990 and December 2009, 183 consecutive patients underwent CABG and concomitant aortic valve replacement for aortic stenosis. The mean follow-up period was 59.8±3.3 months and follow-up was possible in 98.3% of cases. Predictors of mortality were determined by Cox regression analysis.

Results

There were 5 (2.7%) in-hospital deaths. Follow-up of the in-hospital survivors documented late survival rates of 91.5%, 74.8%, and 59.6% at 1, 5, and 10 postoperative years, respectively. Age (p<0.001), a glomerular filtration rate (GFR) less than 60 mL/min (p=0.006), and left ventricular (LV) mass (p<0.001) were significant predictors of mortality in the multivariate analysis.

Conclusion

The surgical results and long-term survival of aortic valve replacement with concomitant CABG in patients with aortic stenosis and coronary artery disease were acceptable. Age, a GFR less than 60 mL/min, and LV mass were significant predictors of mortality.

Prevalence of coronary artery disease in patients with valvular heart disease

To evaluate the usefulness of preoperatie coronary angiography in patients undergoing preoperative investigation because of valvular heart disease, we performed coronary angiography in a consecutive series of 329 patients. The prevalence of significant coronary artery disease was 32%. Asymptomatic coronary artery disease was present in 13%. Angina pectoris proved to be a poor predictor of coronary artery disease in aortic valve disease. In mitral valve disease, however, the specificity was high. A cost-benefit calculation was carried out in order to assess what advantage routine coronary angiography might have. According to this, coronary angiography should be performed in all patients suffering from valvular heart disease with angina pectoris, whereas it can be omitted in younger patients without angina. A cut-off point of 60 years seems appropriate for aortic valve disease and 65 years for mitral valve disease.

[Preoperative coronarography in heart valve disease patients. A probability analysis of coronary lesion]

INTRODUCTION AND OBJECTIVES

The indication of preoperative coronary angiography is routinely performed for patients who are going to valve replacement surgery. The need of coronary angiography is based on age, gender and previous angina, but it is not usually based on risk factors. The purpose of this study has been to find markers to predict the probability of coronary lesion in this group of patients.

PATIENTS AND METHODS

We studied retrospectively a population of 541 patients with valvular heart disease who underwent preoperative coronary angiography from 1989 to 1994. Mean age was 61.8 (range 34-82). There were 301 men and 240 women. We analyzed in each patient different variables such as age, gender, previous angina, hypertension, diabetes mellitus, tobacco and familial predisposition. We correlated these variables with the presence of coronary lesion by multivariate analysis.

RESULTS

There were 73 patients with coronary lesion greater than 50%. The prevalence of significant coronary artery disease was 13.4%. Angina was present in 34.6%. The risk of coronary lesion was defined as odds ratio: previous angina 3.3; tobacco 2.6; diabetes 2.2; hypertension 1.8 and age 1.4. The others variables were not predictor of coronary lesion. The probability of coronary lesion in patients without those variables (angina, tobacco, diabetes, hypertension) was 4%. If we analyzed age, the probability of coronary lesion was 3% in patients under 65 years and 6% above 65 years.

CONCLUSIONS

The lack of previous angina and at least the three risk factors described as predictors of coronary lesion (hypertension, tobacco and diabetes) can define a group of patients with a very low prevalence of coronary lesion, especially if they are under 65 years. It can allow us to avoid preoperatory coronary angiography in patients who undergo valve replacement.

Aortic valve replacement: determinants of operative mortality

Contradictory results have been reported regarding risk factors for aortic valve replacement (AVR). This study was designed to investigate determinants of operative mortality for AVR with emphasis on concomitant coronary artery bypass grafting (CABG) and old age. Between January 1986 and June 1992, 371 patients with a mean age of 61.99 +/- 0.76 years underwent AVR. There were 256 men (69.0%) and 115 women (31.0%). Twenty-six patients (7.0%) were 80 years old or older, and 97 (26.1%) were between 70 and 80 years old. Of these patients, 210 (56.6%) had isolated AVR, 142 (38.3%) had concomitant CABG, and 31 (8.4%) had concomitant mitral valve operations. Twenty patients (5.4%) underwent emergency operation. There were 33 operative deaths (8.9%). Univariate analysis and stepwise multiple logistic regression analysis were used to determine the risk factors for operative mortality. In the univariate analysis, 13 preoperative variables (sex, age, history of congestive heart failure, myocardial infarction, arrhythmia, functional class, class I/II versus III/IV, four variables related to aortic valve pathology, ejection fraction, left ventricular function) and 20 perioperative variables (emergency operation, individual surgeon, myocardial protection by type and route of cardioplegia, type of prosthesis, size of prosthesis, mean size by survival, small versus large size, concomitant procedure, concomitant CABG (versus others or AVR alone), concomitant mitral valve operation (versus others or AVR alone), concomitant CABG and MV operation, aortic cross-clamp time, cardiopulmonary bypass time, use and time of insertion of intraaortic balloon pump, low cardiac output, postoperative complications) were examined.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of coronary artery disease and bypass grafting on early and late survival after valve replacement for aortic stenosis

The influence of coronary artery disease and bypass grafting on survival after valve replacement for aortic stenosis (1975 to 1986, N = 512) was analyzed. Mean follow-up for 30-day survivors was 5.1 years (0.1 to 12.9 years). A total of 205 patients had coronary angiography performed: 122 did not have coronary artery disease, 55 with coronary artery disease underwent bypass grafting, and 28 with coronary artery disease did not. Early mortality rates (less than or equal to 30 days)/5-year cumulative survivals (standard error) were 4.1%/86% (4%), 3.6%/68% (8%), and 17.9%/51% (13%), respectively (p less than 0.05/p less than 0.01). Triple vessel/left main stem disease was more prevalent in patients with coronary disease who underwent bypass grafting (47%) than in those who did not (14%; p less than 0.05). Multivariate analysis revealed that right ventricular failure and omission of bypass grafting in patients with coronary artery disease were independent determinants of early mortality. A Cox regression analysis identified coronary artery disease and aortic valve gradient as determinants of mortality after hospital dismissal, which was not influenced by bypass grafting. On the basis of a coronary artery disease score (positive predictive value for coronary artery disease of 66%) developed on the patients with angiography, 307 patients without angiography were divided into 234 with a low score and 73 with a high score. Early mortality rates/5-year survivals (standard error) were 6.4%/86% (2%) and 16.4%/67% (6%), respectively (p less than 0.01/p less than 0.001). Autopsy revealed stenotic or occlusive coronary artery disease in 92% of 12 early deaths in the group with a high coronary artery disease score and in 33% of 15 in the group with a low score (p less than 0.01). Left ventricular failure and a high coronary artery disease score were independent determinants of early mortality, whereas cardiothoracic index, a high coronary artery disease score, and left ventricular failure were independent predictors of death after hospital dismissal. Despite more severe coronary artery disease, bypass grafting reduced early mortality to a level comparable with that of patients without coronary artery disease, contrasting with a high early mortality rate for unbypassed coronary artery disease. Coronary artery disease increased the late mortality rate, which was not modified by bypass grafting. In the group without angiography, undiagnosed and unbypassed coronary artery disease probably increased both early and late mortality. Coronary angiography should be performed in all adult patients with aortic stenosis, and those with significant coronary artery disease should undergo bypass grafting concomitant with valve replacement.

Factors influencing early and late survival in patients with combined mitral valve replacement and myocardial revascularization and in those with isolated replacement

During a 5 1/2-year period, 251 patients underwent mitral valve replacement (MVR) at our institution: 76 had combined MVR and coronary artery bypass grafting (CABG), and 175 without major coronary artery disease (CAD) had isolated MVR. In-hospital mortality for MVR + CABG was 13.2% (10/76); it was 8.6% (6/70) when patients with preoperative mechanical support were excluded, 7.9% (5/63) for elective operations, and 8.2% (5/61) for nonischemic mitral disease. Overall, in-hospital mortality for isolated MVR was 6.3% (11/175); it was 4.4% (7/161) excluding patients requiring mechanical support and 3.1% (5/157) for elective operations. Of a host of clinical characteristics in patients with MVR +CABG, few were found to influence in-hospital mortality: age greater than 60 years, degree of incapacitation (New York Heart Association Functional Class IV), previous history of myocardial infarction or congestive heart failure, cardiac enlargement (cardiothoracic index greater than 50%), and ischemic mitral disease (33.3% in-hospital mortality; p less than 0.05). Of the invasive variables, only one influenced in-hospital mortality: wall motion score greater than 10 (31.6% in-hospital mortality; p less than 0.01). Of the operative variables studied, the number of grafts (3 or more: 33.3% in-hospital mortality; p less than 0.05), the need for mechanical support (47.4% in-hospital mortality; p less than 0.0001), and emergency operation (38.5% in-hospital mortality; p less than 0.005) had a significant effect on mortality. The type of mitral lesion, the type of prosthesis, the extent of CAD or the completeness of revascularization, the presence of pulmonary hypertension, and atrial fibrillation appeared to have no influence.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery disease and its management: influence on survival in patients undergoing aortic valve replacement

Data from 1,156 patients greater than or equal to 30 years of age who underwent aortic valve replacement alone or with coronary artery bypass grafting from 1967 through 1976 (early series) and 227 similar patients operated on during 1982 and 1983 (late series) were reviewed. In the early series, 414 patients (36%) had preoperative coronary arteriography (group 1): group 1A (n = 224) did not have coronary artery disease, group 1B (n = 78) had coronary artery disease but did not undergo bypass grafting and group 1C (n = 112) had coronary artery disease and underwent bypass grafting. The 742 patients in group 2 did not have preoperative arteriography. Operative mortality rates (30 day) in groups 1A, 1B, 1C and 2 were 4.5, 10.3, 6.3 and 6.3%, respectively (p = NS). The 10 year survival in both groups 1 and 2 was 54%; in groups 1A, 1B and 1C it was 63, 36 and 49%, respectively (1A and 1B, p less than 0.01). In the late series, the 227 patients were divided into similar groups (group 1A, n = 73; 1B, n = 32; 1C, n = 99), and 90% had preoperative coronary arteriography. Operative mortality rates (30 day) for groups 1A, 1B and 1C were 1.4, 9.4 and 4.0%, respectively; that for group 2 (no preoperative arteriography, n = 23) was 4.3%. Definition of coronary anatomy by angiography seems important in most patients greater than or equal to 50 years old who are candidates for aortic valve replacement, and bypass grafting is recommended for those with significant coronary artery disease.

Late results of combined mitral valve replacement and coronary bypass surgery

The incremental risk of coronary bypass surgery was analyzed in 718 patients undergoing mitral valve replacement between 1971 and 1983. Ninety-eight patients (14%) had significant coronary artery disease requiring coronary bypass surgery. In 70 of these patients, the origin of the mitral valve disease was nonischemic, whereas 28 patients had ischemic mitral regurgitation unsuitable for conservative valve surgery. There were six operative deaths (9%) and four perioperative myocardial infarctions (6%) after mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease. Operative mortality was related to low output cardiac failure before operation or perioperative myocardial infarction. Actuarial curves predict survival (+/- standard error) of 55 +/- 7% at 5 years and 43 +/- 8% at 10 years. Preoperative functional class was the only significant predictor of long-term survival in this group (p less than 0.05). The actuarial survival of the 620 patients without coronary artery disease who underwent mitral valve replacement alone was 63 +/- 3% at 10 years. This was significantly better than that of the 70 patients who underwent mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease (p less than 0.001). Conversely, 5 year survival of the 28 patients with ischemic mitral regurgitation was 43 +/- 10%. This confirms the negative detrimental effect of an ischemic origin of mitral valve disease on survival after mitral valve replacement and coronary bypass surgery (p less than 0.0001).

Association of coronary artery disease and valvular heart disease in Chile

This study analyzes the prevalence of coronary artery disease (CAD) among patients with rheumatic valvular heart disease (VHD) in Chile. Coronary angiography was performed in all patients referred to cardiac catheterization with VHD who were over age 50 years and who had angina or ECG signs of ischemia. A total of 100 patients entered the study. Significant CAD (greater than 50% obstruction) was found in 14% of the cases: 7% in patients with mitral valve disease (MVD), 18% in aortic valve disease (AVD), and 21% in combined mitral and aortic valve disease (MAVD). Angina was present in 14% of the patients with MVD, 63% with AVD, and 53% with MAVD. Only 57% of patients with CAD had angina pectoris; 20% with angina had CAD. Hemodynamic parameters and left ventricular ejection fraction were not correlated with the presence or absence of CAD. We conclude that in patients with valvular heart disease, the incidence of CAD is lower in Chile than previously reported in the English literature. We confirmed the fact that angina is often not associated with CAD, and that CAD is often present in the absence of angina.

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.

Aortic valve replacement and coronary bypass in patients with severe stenosis of the left main coronary artery

Adequate myocardial protection is difficult to achieve during operations for combined aortic valve disease and severe stenosis of the left main coronary artery. A double cross-clamp technique, which facilitates the delivery of cardioplegic solution to the myocardium, is described here. We reviewed the experiences of 11 patients, 6 of whom underwent operation using the new technique.

Valvular heart disease: a perspective

Valve replacement has been one of the most important advances in the management of patients with valvular heart disease. The 10 and 15 year survival rate after isolated aortic and mitral valve replacement with the Starr-Edwards valve is 56 and 44%, respectively. At 5 and 7 years, survival with the Björk-Shiley, porcine bioprosthesis and the Starr-Edwards valve is similar. Patients operated on during the last 5 to 10 years have a much better survival rate than those operated on in the 1960s; therefore, the 10 and 15 year survival of those operated on recently should improve. All patients with a mechanical prosthesis need long-term anticoagulant therapy with drugs of the coumadin type. Porcine bioprostheses have a low failure rate up to 5 years after valve replacement; after this, valve failure occurs at an increasing rate, but the incidence at 10 and 15 years is not known. Valve replacement usually produces a marked improvement in the symptomatic status of the patient because of improved hemodynamics; ventricular function is improved in selected subsets of patients. The role of long-term vasodilator therapy has not been fully determined. Antibiotic prophylaxis for secondary prevention of rheumatic carditis and for prevention of infective endocarditis is important.

Coronary arteriography in isolated aortic and mitral valve disease

Coronary arteriographic findings in 200 patients with isolated aortic and mitral valve disease were reviewed to examine the relationship between obstructive (greater than 50% diameter stenosis) coronary artery disease (CAD) and angina pectoris (AP). Of 100 patients with aortic valve disease, 30 had CAD of whom 20 gave a history of AP. Thirty-two of 52 patients (61%) with AP did not have CAD and 10 of 48 (21%) had CAD without AP. CAD was evenly distributed among patients with aortic stenosis, incompetence and mixed aortic valve disease. CAD was found in 23 of 100 patients with mitral valve disease. Sixteen of 32 patients with mitral incompetence had CAD of whom four had AP. Seven of 68 patients with mitral stenosis or mixed mitral valve disease had CAD. AP was noted by four of these seven patients but by none of the 61 with normal coronary arteriograms (p less than 0.0001). Asymptomatic CAD was more common among patients with mitral incompetence (12/28 vs 3/64 p less than 0.005). AP was an unreliable marker for CAD in aortic valve disease or mitral incompetence. Conversely, CAD was uncommon without AP in mitral stenosis or mixed mitral valve disease. Coronary arteriography seems indicated in the pre-operative assessment of patients aged greater than or equal to 40 years with aortic valve disease or mitral incompetence. Its value is limited in patients with mitral stenosis or mixed mitral valve disease without AP.

Valve replacement without preoperative cardiac catheterization

During the year 1978, the decision to perform cardiac catheterization in patients with valvular heart disease was delayed until clinical and noninvasive assessment have been completed. As a result, 184 patient underwent operation without invasive studies, and 59 had elective catheterization. Another 62 patients were referred during the same period for valve replacement after routine catheterization had been performed elsewhere. Age, sex distribution, symptoms, and cause of valve disease were similar in all three groups, although we managed emergencies and second operations more frequently without catheterization. In all patients, the preoperative diagnosis was confirmed, and no unexpected pathologic process was encountered. Operative mortality was the same in all three groups, and after two years of follow-up there was no difference in survival or symptoms. No uncorrected valve lesions became apparent in uncatheterized patients. We conclude that routine catheterization is unnecessary before valve replacement but can be reserved for specific indications in some patients.