Risks of mitral valve replacement and mitral valve replacement with coronary artery bypass

An excellent result of surgical treatment in patients with severe pulmonary arterial hypertension following mitral valve disease

Objective

Observe the efficacy of surgical treatment in patients with severe pulmonary arterial hypertension caused by mitral valve disease.

Methods

We examined the results of surgical treatment in 32 patients with mitral valve disease and severe pulmonary arterial hypertension (pulmonary arterial systolic pressure ≥ 80 mmHg) retrospectively. Operative and postoperative data collection included type of the surgery, cardiopulmonary bypass time, cross-clamp time and the mortality rate. Pulmonary arterial systolic pressure, left atrial diameter, left ventricular end-diastolic diameter, and left ventricular ejection fraction were recorded and compared.

Results

A total number of 32 patients had the operation of mitral valve replacement. Among those subjects, twenty-seven patients were surgically replaced with mechanical prosthesis and five patients with tissue prosthesis. Only one patient died of pneumonia, with a mortality rate of 3.1 %. The statistical results of preoperative and postoperative echocardiographic data showed significant decrease in pulmonary arterial systolic pressure (101.2 ± 20.3 versus 48.1 ± 14.3 mmHg, P < 0.05), left atrial diameter(67.6 ± 15.7 versus 54.4 ± 11.4 mm, P < 0.05) and left ventricular end-diastolic diameter (52.3 ± 9.5 versus 49.2 ± 5.9 mm, P < 0.05). There was no significant change in left ventricular ejection fraction (59.2 ± 6.5 versus 57.9 ± 7.6, P = NS). At the time of follow-up, twenty-eight (96.6 %) patients were classified in New York Heart Association functional class I or II, one(3.4 %) in class III, with the mortality rate is zero percent.

Conclusions

Mitral valve replacement can be performed successfully in patients with mitral valve disease and severe pulmonary arterial hypertension with an acceptable perioperative risk.

Right ventricular and septal function in patients with pulmonary hypertension

OBJECTIVE

Pulmonary hypertension (PHT) exacerbates the functions of both ventricles. This prospective, randomised study was planned to investigate the effects of PHT on kinetics of both ventricles and the septum.

METHODS

Twenty-five patients were randomly selected among the patients who had been planned to undergo mitral valve replacement (MVR) because of isolated mitral stenosis and divided into two groups according to their preoperative pulmonary artery pressure (PAP) values. Blood pool gated single photon emission tomography (BPGS) and transthoracic echocardiography were performed. Ventricles' regional, global and functional parameters were also assessed by using pulsed wave Doppler tissue imaging (DTI).

RESULTS

Preoperative and postoperative PAP of the group 1 (PAP < 50 mmHg) were 40.0 ± 2.8 and 30.0 ± 2.6 mmHg (p = 0.03), group 2 (PAP ≥ 50 mmHg) were 71.9 ± 4.7 and 50.6 ± 3.5 mmHg (p < 0.05). The global right and left ventricle scores were decreased after the operation. The decrement was only significant in group 2. Considering the septal kinetics, right ventricle septal score was decreased from 7.6 to 3.3 (p < 0.05) in group 1, from 3.8 to 1.6 (p < 0.05) in group 2 postoperatively.

CONCLUSION

Following MVR, a decrement in PAP values, and an improvement in ventricular function, especially in the right ventricular and septal kinetics were achieved. Furthermore, it was found that both DTI and BPGS techniques are beneficial to investigate the functional changes postoperatively and in the follow-up period of the patients who undergo mitral valve surgery.

Predictors of mortality for patients undergoing cardiac valve replacements in New York State

BACKGROUND

The objective of this study was to identify the mortality rates and significant independent risk factors for mortality for each of six valve replacement groups.

METHODS

A total of 14,190 patients who underwent valve replacement in New York State from 1995 to 1997 were classified into six major groups and significant independent risk factors for inpatient mortality were identified for each of the groups using stepwise logistic regression.

RESULTS

Mortality rates ranged from 3.33% for isolated aortic valve surgical procedures to 18.72% for multiple valve replacements with coronary artery bypass graft operations. The number of years in excess of age 55 was a significant multivariate predictor of mortality for all six groups of patients. Shock was a significant predictor for five of the six groups, and in each of those groups it was the risk factor with the highest odds ratio.

CONCLUSIONS

Significant patient risk factors are relatively consistent across different types of valve replacement procedures. The probability of survival from valve surgical procedures is highly dependent on the patient's preoperative profile and the type of valve operation.

Mild renal failure is associated with adverse outcome after cardiac valve surgery

The present study was performed to ascertain whether the presence of mild renal failure (defined as a serum creatinine concentration of 1. 5 to 3.0 mg/dL) is an independent risk factor for adverse outcome after cardiac valve surgery. An extensive set of preoperative and postoperative data was collected in 834 prospectively evaluated patients undergoing cardiac valve surgery at 14 Veterans Affairs Medical Centers. Univariate and multivariable analyses were performed to determine whether an independent association of mild renal dysfunction with adverse outcomes was present. Patients with mild renal failure had significantly greater 30-day mortality rates (P = 0.001; 16% versus 6%) and frequency of postoperative bleeding (P = 0.023; 16% versus 8%), respiratory complications (P = 0.02, 29% versus 16%), and cardiac complications (P = 0.002; 18% versus 7%) than patients with normal renal function (serum creatinine <1.5 mg/dL) when controlling for multiple other variables. The presence of a serum creatinine concentration of 1.5 to 3.0 mg/dL is significantly and independently associated with adverse outcomes after cardiac valve surgery.

Risk stratification for cardiac valve replacement. National Cardiac Surgery Database. Database Committee of The Society of Thoracic Surgeons

BACKGROUND

The Society of Thoracic Surgeons National Database Committee is committed to risk stratification and assessment as integral elements in the practice of cardiac operations. The National Cardiac Surgery Database was created to analyze data from subscribing institutions across the country. We analyzed the database for valve replacement procedures with and without coronary artery bypass grafting to determine trends in risk stratification.

METHODS

The database contains complete records of 86,580 patients who had valve replacement procedures at the participating institutions between 1986 and 1995, inclusive. The 1995 harvest of data was conducted in late 1996 and available for evaluation in 1997. These records were used to conduct an in-depth analysis of risk factors associated with valve replacement and to provide prediction of operative death by using regression analysis. Regression models were made for six subgroups.

RESULTS

Adverse patient risk factors, including diabetes, hypertension and reoperation, but not ventricular function, increased over time. There were trends with regard to increasing age of the various population subsets. The types of prostheses used remained similar over time, with more mechanical prostheses than bioprostheses used for both aortic and mitral valve replacement. There was a trend toward increased use of bioprostheses in aortic replacements and decreased use in mitral replacements between 1991 and 1995 than between 1986 and 1990. The mortality rate was determined by patient subset for primary operation and reoperation and by urgency status. The modeling showed that the predicted and observed mortality correlated for all age groups and within patient subsets.

CONCLUSIONS

Risk modeling is a valuable tool for predicting the probability of operative death in any individual patient. This large, multiinstitutional database is capable of determining modern operative risk and should provide standards for acceptable care. The study illustrates the importance of risk stratification for early death both for the patient and the surgeon.

Echocardiographic prediction of survival after surgical correction of organic mitral regurgitation

BACKGROUND

Left ventricular dysfunction is a frequent cause of death after successful surgical repair of mitral regurgitation. The role of preoperative echocardiographic left ventricular variables in the prediction of postoperative survival and thus their clinical implications remain uncertain.

METHODS AND RESULTS

The survival of 409 patients operated on between 1980 and 1989 for pure, isolated, organic mitral regurgitation and with a preoperative echocardiogram (within 6 months of operation) was analyzed. The overall survival was 75% at 5 years (90% of expected), 58% at 10 years (88% of expected), and 44% at 12 years (73% of expected). Operative mortality was 6.6% and markedly improved from 1980 to 1984 (10.7%) to 1985 to 1989 (3.7%). Multivariate analysis showed that age (P = .0003), date of operation (P = .003), and functional class (P = .016) but not left ventricular function were predictors of operative mortality. In the most recent period (1985 to 1989), operative mortality was 12.3% in patients age 75 years or older and 1.1% in patients younger than 75 years. Late survival was analyzed in the operative survivors. Multivariate analysis showed that the most powerful predictor was echocardiographic ejection fraction (EF) (P = .0004), followed by age (P = .0031), creatinine level (P = .0062), systolic blood pressure (P = .0164), and presence of coronary artery disease (P = .0237). The late survival at 10 years was 32 +/- 12% for patients with EF < 50%, 53 +/- 9% for EF 50% to 60%, and 72 +/- 4% for EF > or = 60%. The hazard ratio compared with EF > or = 60% was 2.79 (95% confidence interval, 1.65 to 4.72) for EF < 50% and 1.81 (95% confidence interval, 1.11 to 2.95) for EF 50% to 60%. Echocardiographic EF remained the best predictor of late survival, even when combined with left ventricular angiographic variables. The survival of patients with EF > or = 60% was 100% of expected at 10 years but was better in patients in class I or II than in those in class III or IV (82 +/- 6% versus 59 +/- 6%, respectively, at 10 years; P = .0021). The preoperative predictors of operative and late mortality remained significant independent of the type of surgical correction performed in combined multivariate analyses.

CONCLUSIONS

In organic mitral regurgitation, (1) operative mortality has markedly decreased recently, being at a low 1.1% in patients younger than 75 years, and is predicted by age and symptoms and not by left ventricular function, and (2) left ventricular EF measured by echocardiography is the most powerful predictor of late survival. These results suggest that surgical treatment should be considered early, even in the absence of severe symptoms, in patients with severe mitral regurgitation, before left ventricular dysfunction occurs.

Mitral valve replacement: indications, choice of valve prosthesis, results, and long-term morbidity of porcine and mechanical valves

Indications for specific valve types, whether they be mechanical or bioprosthetic, have been rigorously defined in recent years. Candidates for bioprosthetic valves would be: older patients, patients who are noncompliant or have contraindications to anticoagulation, patients in normal sinus rhythm, and young females desirous of future pregnancy. Recent data suggest that patient age and presence of coronary artery disease may significantly alter the indications for mechanical or tissue valves. There is mounting evidence that patients without coronary disease in their 60s and 70s who require valve replacement are better served with a mechanical prosthesis. At Emory University Hospitals, 440 patients operated upon between 1974 and 1981 were followed for a mean period of 8.3 years. No patients having coronary artery disease were included in the cohort. Survival at 10 years was 64%. The actuarial freedom from all major valve related complications at the end of 10 years is compared to other series. Data suggests that patient survival for mitral valve replacement is affected by the etiology of the valve disease necessitating the operation. The best survival occurs in patients in whom the mitral valve replacement is for myxoid degeneration and may explain the excellent survival to be expected for mitral valve repair and concomitant coronary bypass. The most significant factor increasing morbidity and mortality in patients with mitral valve replacement and coronary artery disease is high end-diastolic pressure associated with significant depression of regional wall motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous mitral valvuloplasty in surgical high risk patients

Among 126 consecutive patients undergoing percutaneous mitral valvuloplasty, 34 were judged to be at high risk for surgery on the basis of age greater than 70 years (n = 13), New York Heart Association functional class IV (n = 11), ejection fraction less than or equal to 35% (n = 3), severe pulmonary hypertension (n = 7), need for associated coronary bypass (n = 4) or additional valve surgery (n = 20) or severe pulmonary disease (n = 3). Baseline features of the high risk group were substantially worse than those of the other patients: age (65 +/- 11 versus 49 +/- 12 years; p = 0.0001) and echocardiographic score (9.4 +/- 1.8 versus 8.2 +/- 1.5; p = 0.005) were higher, whereas cardiac output (2.9 +/- 0.9 versus 4.1 +/- 1.2 liters/min; p = 0.0001) and mitral valve area (0.9 +/- 0.4 versus 1.1 +/- 0.3 mm2; p = 0.002) were lower. Three high risk patients experienced technical failures and three others had major complications. Among the remaining 28 patients, 18 (65%) had a complete hemodynamic success, 4 (14%) an incomplete success and 6 (21%) hemodynamic failure. Stepwise logistic regression analysis retained echocardiographic score as the only factor independently predictive of success. The percent increase in mitral valve area also correlated with echocardiographic score (r = 0.51, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Initial report of the Veterans Administration Preoperative Risk Assessment Study for Cardiac Surgery

This study was authorized by the Department of Veterans Affairs to improve the quality assurance of cardiac surgery by assessing preoperative risk factors and relating them to operative mortality. Data were received on 10,480 patients over a 2-year period. Preoperative risk variables were subjected to univariate and multivariate logistic regression analyses. Significant variables for coronary artery bypass grafting after logistic regression analysis in order of importance are previous cardiac operation, priority of operation, New York Heart Association functional class, peripheral vascular disease, age, pulmonary rales, current diuretic use, and chronic obstructive pulmonary disease. For patients undergoing valve or other cardiac operations with or without coronary artery bypass grafting, those variables found to be significant after multivariate logistic regression analysis are priority of operation; age; peripheral vascular disease; great vessel repair; all other except aortic valve replacement, mitral valve replacement, and great vessel repair; mitral valve replacement; and cardiomegaly. By identifying these current risk factors and the coefficients from the multivariate stepwise logistic regression analysis, expected mortality can be calculated. We propose that the ratio of observed to expected mortality is a better measure of quality of care than unadjusted mortality.

Emergent coronary angioplasty in the treatment of acute ischemic mitral regurgitation: long-term results in five cases

Severe mitral regurgitation in the setting of an evolving myocardial infarction is associated with a high operative mortality rate. Five patients with acute severe mitral regurgitation secondary to ischemic posterior papillary muscle dysfunction underwent emergent percutaneous transluminal coronary angioplasty. Two patients were in cardiogenic shock and required intraaortic balloon counterpulsation. Angioplasty resulted in rapid improvement in hemodynamic variables, and all patients were discharged at a mean of 10 days after the procedure. Long-term follow-up study (mean 35 +/- 6 months) revealed normal mitral valve function angiographically and by Doppler echocardiography in four patients. Repeat angioplasty was required in one patient, and another underwent coronary artery bypass surgery without valve replacement for restenosis. One patient developed progressive mitral regurgitation and required elective mitral valve replacement 12 months after angioplasty. These preliminary findings suggest that emergent coronary angioplasty is a useful therapeutic intervention in the treatment of ischemic mitral regurgitation and is associated with a favorable long-term outcome.

Current status of cardiac surgery: a 40 year review

Cardiac surgery has undergone dramatic advancements during the past 3 decades. The introduction of cardiopulmonary bypass and cardioplegic arrest ushered in the true era of open heart surgery. Bioprostheses and mechanical valves as well as techniques for valve reconstruction permit routine repair or replacement of stenotic and regurgitant native valves. Progress in the disciplines of mechanical and electrical engineering has led to the development of pocket watch-sized, physiologically responsive pacemakers as well as a variety of circulatory assist devices that include the intraaortic balloon pump, ventricular assist device and total artificial heart. The synthesis of cardiotonic and vasoactive drugs and advancements in anesthetic management, postoperative monitoring and nursing care greatly facilitate perioperative patient management. This summary of state of the art cardiac surgery begins with a brief historical background followed by a review of recent advances in six main categories: coronary artery disease, acquired valvular heart disease, congenital cardiac disease, cardiac transplantation, myocardial preservation and mechanical circulatory assistance. In conducting the review of recent literature, particular attention was directed to large clinical series that document the results of contemporary surgical procedures, novel therapeutic approaches to current clinical problems and unresolved controversies in the field of cardiac surgery. The abundance of surgical literature and constraints on the length of this article do not permit an exhaustive review. Apologies are extended to clinicians and laboratory investigators whose important contributions to the understanding and treatment of cardiac disease are not included herein.

Actuarial analysis of late results after closed mitral valvotomy

The long-term results of closed mitral valvotomy performed between 1978 and 1985 in 198 patients with noncalcific mitral stenosis were analyzed. Follow-up data were available on 185 patients (93%); 1 patient died in the postoperative period, and 12 foreign patients were lost to follow-up. At the 4-year and 8-year intervals, 91% and 80% of patients, respectively, were event free (not in need of further operative procedures). By multivariate analysis, the factor preoperative mild mitral regurgitation showed a tendency to influence the event-free period. By univariate analysis, postoperative mitral regurgitation significantly reduced the event-free period. Twenty-one patients subsequently underwent mitral valve replacement; 8 for mitral regurgitation, 10 for mitral stenosis, and 3 for mixed mitral regurgitation and stenosis. By multivariate analysis, the reason for reoperation significantly influenced the length of the event-free period. The patients with mitral regurgitation required mitral valve replacement sooner than those with mitral stenosis. Advanced age, sex, previous valvotomy, preoperative New York Heart Association Functional Class, low mitral valve leaflet excursion, and pulmonary hypertension had no influence on the long-term result.

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)

Preoperative risk assessment in cardiac surgery: comparison of predicted and observed results

In the present climate of quality-assurance policies, rigorous requirements for informed consent, and a constantly changing patient population, a system of preoperative risk assignment and postoperative correlation was developed to monitor and evaluate surgical performance. Patients were categorized by operation, priority (emergent, urgent, elective), New York Heart Association Functional Class, and risk. Risk was assigned before operation using data from the Coronary Artery Surgery Study (CASS) and the recent literature. Data were collected by a full-time data manager and were stored and analyzed by computer. From January 1, 1984, to July 1, 1985, 1,303 patients underwent operation for acquired disease. This group included 913 patients undergoing isolated primary coronary artery bypass grafting (CABG). The comparison of predicted and observed results showed: (Table: see text). For patients undergoing isolated primary CABG, the elective group had an operative mortality of 0.6% (2/329); the urgent group, 1.1% (5/450); and the emergent group, 5.2% (7/134). Preoperative risk assignment is an effective method of quality assurance. Female sex and age older than 60 years, which predicted an operative mortality of 2 to 5% in the CASS study and other recent series, did not predict a similar risk in our series.

Concomitant mitral valve repair or replacement and coronary revascularization

Patients undergoing combined mitral valve replacement and coronary revascularization require surgical skill and especially judgment for optimal results. In our hands, cardioplegia has not been a pivotal event in affecting survival, and this probably relates to our previous philosophy of limiting the hypothermic ischemic episodes to 15-minute intervals. Currently, we believe that valve repair, when it can be accomplished, is preferable to valve replacement, especially in the patient with ischemic mitral valve disease. When repair cannot be satisfactorily accomplished, replacement with retention of the posterior leaflet seems clinically to be associated with less disturbance of left ventricular function.