Aortic valve replacement combined with myocardial revascularization

Impact of Preoperative Left Ventricular Ejection Fraction on Long-Term Survival After Aortic Valve Replacement for Aortic Stenosis

Background—

The survival of patients who undergo aortic valve replacement (AVR) for severe aortic stenosis with reduced preoperative ejection fractions (EFs) is not well described in the literature.

Methods and Results—

Patients undergoing AVR for severe aortic stenosis were analyzed using the Northern New England Cardiovascular Disease Study Group surgical registry. Patients were stratified by preoperative EF (≥50%, 40%–49%, and <40%) and concomitant coronary artery bypass grafting. Crude and adjusted survival across strata of EF was estimated for patients up to 8 years beyond their index admission. A total of 5277 patients underwent AVR for severe aortic stenosis between 1992 and 2008. There were 727 (14%) patients with preoperative EF <40%. Preoperative EF had minimal effect on postoperative morbidity. There was no difference in 30-day mortality across EF strata among the isolated AVR cohort. Preserved EF conferred 30-day survival benefit among the AVR+coronary artery bypass grafting population (EF≥50%, 96%; EF<40%, 91%; P =0.003). Patients with preserved EF had significantly improved 6-month and 8-year survival compared with their reduced EF counterparts.

Conclusions—

Survival after AVR or AVR+coronary artery bypass grafting was most favorable among patients with preoperative preserved EF. However, patients with mild to moderately depressed EF experienced a substantial survival benefit compared with the natural history of medically treated patients. Furthermore, minor reductions of EF carried equivalent increased risk to those with more compromised function suggesting patients are best served when an AVR is performed before even minor reductions in myocardial function.

Aortic Valve Replacement and Concomitant Coronary Artery Bypass: Assessing the Impact of Multiple Grafts

BACKGROUND

The impact of multivessel coronary artery disease and multivessel coronary artery bypass grafting on outcomes after combined aortic valve replacement and coronary artery bypass grafting (AVR-CABG) has not been sufficiently evaluated.

METHODS

We retrospectively reviewed all patients who underwent AVR-CABG at our institution between January 2000 and December 2004. Patients with any previous or concomitant procedures were excluded. The Kaplan-Meier method was used to calculate survival and freedom from postoperative repeat revascularization. Predictors of mortality were determined by Cox regression analysis.

RESULTS

The study cohort consisted of 233 AVR-CABG patients. Mean follow-up was 2.2 +/- 1.7 years with one patient lost to follow-up. Preoperative clinical characteristics were well-matched between patients who received one (n = 86), two (n = 81), or three or four (n = 66) bypass grafts. Operative mortality was 9.3%, 11.1%, and 7.6%, respectively (p = 0.76). Patients in all groups demonstrated significant improvement in New York Heart Association (NYHA) status (p < 0.01). Freedom from postoperative repeat revascularization for all patients after five years was 96.8% and did not differ among groups (p = 0.93). Five-year survival for each group was 63.6%, 72.4%, and 63.9%, respectively (p = 0.91). Emergent operation, ejection fraction less than 0.30, operative age greater than 65 years, NYHA class III/IV, and chronic obstructive pulmonary disease were significant predictors of mortality. The number of stenosed vessels, the number of bypass grafts, incomplete revascularization, and the presence of aortic stenosis or aortic insufficiency did not predict mortality.

CONCLUSIONS

For patients undergoing AVR-CABG, the number of bypass grafts does not adversely affect survival. Rather, a patient's preoperative risk factors are a better predictor of outcome.

Mitroflow pericardial bioprosthesis in the aortic position. Low incidence of structural valve deterioration in elderly patients during an 11-year follow-up

Aortic valve replacement with Mitroflow pericardial bioprosthesis, with or without concomitant bypass surgery was performed on 403 consecutive patients between March 1984 and December 1994. The mean age was 74 (range 10-92) years, with male/female ratio 183/220. Early mortality was 3.5% (14/403) and late mortality 25% (99/389). Actuarial survival was 35.4%+/-9.4% at 10 years and freedom from valve-related mortality 86.2%+/-9.6% at 8 years (total follow-up 1 270 years). The thromboembolic rate was 6.5% (fatal 0.7%)/patient year. The incidence of prosthetic valve endocarditis was 0.6% (fatal 0.3%)/patient year. Structural valve deterioration was found in 0.8%/patient year (no fatality). Actuarial freedom from all reoperations at 8 years was 92.4+/-8%. The Mitroflow pericardial heart valve is proposed as a good choice for aortic valve replacement in elderly patients, in view of the low rates of reoperation, anticoagulant treatment and valve-related thromboembolism.

Ten-year trends in heart valve replacement operations

BACKGROUND

There has been increasing concern in recent years about the quality and cost of heart valvular replacement procedures. The purpose of this study is to examine the profile of patients undergoing valvular operations during the past decade, and to look at trends in outcome and resource utilization over that period.

METHODS

Clinical and procedural data of 2,972 patients undergoing heart valve replacement at Emory University Hospitals between 1988 and 1997 were recorded prospectively on standardized forms by trained medical personnel and entered into a computerized database.

RESULTS

There were 1,802 patients undergoing aortic valve replacement (AVR), 966 undergoing mitral valve replacement (MVR), and 204 undergoing combined aortic and mitral valve procedures (AVR + MVR). No patients were excluded. There was a statistically significant trend for patients undergoing AVR, MVR, or AVR + MVR over time to be older and sicker by multiple criteria. Nonetheless, procedural outcome and inhospital mortality for patients undergoing AVR remained unchanged. Cost and length of stay increased from 1988 to 1992 when a concerted effort to decrease resource utilization began. Between 1992 and 1997 for AVR, length of stay decreased from 13.4 to 8.0 days and cost from $37,047 to $21,856. Similarly, between 1992 and 1997 for MVR, length of stay decreased from 15.6 to 8.1 days and cost from $45,072 to $21,747. The net result over the time period from 1988 to 1997 was an average decline in the cost of operation of $785 a year, adjusted for other factors.

CONCLUSIONS

This study reveals that outcome of valvular replacement during the period from 1988 to 1997 has remained constant despite the patients becoming older and sicker during the same period. This constant outcome has been accomplished, but length of stay has decreased significantly. Hospital costs increased during the first years of the study period, but then decreased to levels in 1997 that were equal to or significantly less than 1988 levels.

Efficacy of the internal mammary artery in combined aortic valve replacement-coronary artery bypass grafting

BACKGROUND

While internal mammary artery (IMA) use predicts improved survival after coronary bypass grafting (CABG), it remains unknown whether patients undergoing concomitant aortic valve replacement (AVR) realize a similar benefit.

METHODS

All patients at a single teaching institution, undergoing combined AVR-CABG, which included a graft to the left anterior descending coronary artery (LAD) from 1984 to 1994 (n = 227) were examined retrospectively.

RESULTS

Patients receiving an IMA graft (yesIMA, n = 135) and patients receiving only saphenous vein grafts (nonIMA, n = 92) were not different in their presenting symptoms, or in their incidence of preoperative risk factors. The patients with IMA were more likely to be male, have a later year of operation, be younger, and have a greater body surface. Morbidity was not different between groups. IMA use did not affect 30-day mortality. Long-term actuarial survival was greater in the group with IMA (63% +/- 7% vs 42% +/- 6% at 5 years, p < 0.01). A multivariate Cox proportional hazards model demonstrated that use of an IMA graft improved survival, while recent myocardial infarction, diabetes, earlier year of operation, and lower ejection fraction diminished long-term survival. The relative risk of IMA grafting was 0.570.

CONCLUSIONS

Within the limits of a retrospective analysis, patients in a modern era of cardiac operation, who undergo combined AVR-CABG, do not suffer increased morbidity from IMA use, and may realize a survival benefit from use of the IMA as a conduit for bypass of the LAD coronary artery.

Actual failure rates: A method of assessing tissue valve reoperation rates

BACKGROUND

Patients older than age 70 with coronary disease undergoing mitral valve replacement have a limited survival rate, suggesting that few of these patients will require reoperation if they receive a tissue mitral valve. However, traditional actuarial analysis of valve durability censors patients who die before valve failure and doesn't reflect the lower frequency of reoperation in patient subgroups with limited survival rates.

METHODS

Actual or cumulative reoperation rates represent the rates of reoperation in patients without censoring for death and estimate the risk that the valve will fail before the patient dies. The actual rates of valve rereplacement were determined in 255 recipients of tissue mitral valves, categorizing patients by age and presence of coronary artery disease at 8 years after surgery and compared with standard actuarial estimates of valve durability.

RESULTS

Operative mortality rates were 17.5% for patients with coronary artery disease and 6.0% for those without (P <.001). At 8 years, the actual reoperation rates for patients younger than age 70 with and without coronary artery disease were 9.2% (n = 76) and 10% (n = 90), respectively. In patients older than age 70 without coronary artery disease the reoperation rate was 9.4% (n = 32). In contrast, the actual reoperation rate was only 1.7% (n = 58) in patients older than age 70 with coronary artery disease. This rate was significantly lower (P =.05) than the other groups. The difference in reoperation rates was not significant if standard actuarial analysis was used.

CONCLUSIONS

Actual reoperation rates are significantly lower in patients older than 70 years with CAD receiving mitral tissue valves than in younger patients or in patients without coronary artery disease. Calculation of actual reoperation rates provides a unique and clinically useful perspective in evaluating data on prosthetic valve reoperation rates.

Surgery for Combined Rheumatic Valve and Coronary Artery Disease

Between 1986 and 1996, 147 patients underwent valve replacement combined with coronary artery bypass grafting. The mitral valve was replaced in 104 patients, the aortic valve in 34, and both mitral and aortic valves were replaced in 9. One hundred and twenty-two (83%) were male with a mean age of 56 ± 5 years (range, 38 to 77 years). The mean age for female patients was 57.9 ± 5 years (range, 38 to 70 years). All of the patients had rheumatic valve disease. Preoperatively, 68% were in New York Heart Association functional class III or IV and 32% were in class II. A total of 252 distal anastomoses were performed (mean, 1.71 per patient) in these patients of whom 48.9% had single-vessel disease, 45% had two-vessel or three-vessel disease, and 6.1% had left main coronary artery disease. The hospital mortality rate was 10.2%. Three patients died during the follow-up period and the overall actuarial survival rate at 10 years was 96.6% ± 1.9%. Operations that combine both valve replacement and coronary artery bypass are performed more frequently because perioperative risk has decreased through more effective myocardial protection. If untreated, both coronary artery disease and significant valve disease may reduce patient survival.

The impact of age, coronary artery disease, and cardiac comorbidity on late survival after bioprosthetic aortic valve replacement

OBJECTIVES

This study was designed to determine the effects of age, coronary artery disease and other cardiac comorbidities on late outcome following bioprosthetic aortic valve replacement.

METHODS

Data were prospectively collected on 670 patients undergoing aortic valve replacement with the Hancock II bioprosthesis (Medtronic, Inc, Minneapolis, Minn) between 1982 and 1994. Mean patient age was 65 +/- 12 years (median, 68 years; range, 18-86 years). Follow-up was 99.7% complete at 69 +/- 40 months (median, 66 months; range, 0. 1-168 months). Survival and freedom from reoperation were evaluated univariately by Kaplan-Meier analysis and multivariably by Cox regression.

RESULTS

After adjustment for gender, Cox regression analysis revealed that age of 65 years or older, left ventricular dysfunction, the presence of coronary artery disease, and advanced New York Heart Association functional classification were associated with a higher risk of late death. At 12 years, survival was significantly different by Kaplan-Meier analysis for both age younger than 65 years (71% +/- 4%) versus age 65 years or older (36% +/- 7%; P <.0001), left ventricular function grades 3 and 4 (26% +/- 13%) versus grades 1 and 2 (59% +/- 4%; P <.0001), no coronary artery disease (65% +/- 4%) versus coronary artery disease (35% +/- 8%; P <.0001), and functional class IV (33% +/- 9%) versus classes I to III (62% +/- 4%; P <.0001). Only 9 patients experienced primary tissue failure, all of whom were younger than 65 years of age. At 12 years, the freedom from primary tissue failure was 84% +/- 4% for those patients younger than 65 years of age, and 100% for those 65 years of age or older (P =.006).

CONCLUSIONS

Long-term survival after aortic valve replacement is highly dependent on age, coronary artery disease, functional class, and left ventricular function, although bioprosthetic durability is dependent almost solely on age. Due to increased valve durability in patients who are 65 years of age or older, the Hancock II bioprosthesis may be an ideal aortic valve substitute in this age group. In patients who are younger than 65 years of age with advanced functional class, impaired left ventricular function, and coronary artery disease, this valve may also be used with a low probability of primary tissue failure. Patients without additional cardiac comorbidity may outlive their bioprosthetic valve, leading to reoperation.

Aortic valve replacement for octogenarians: are small valves bad?

BACKGROUND

As the population ages, more octogenarians become candidates for aortic valve replacement. Many octogenarians, particularly women, have a small aortic annulus and there is uncertainty as to the optimal management of this situation in that age group.

METHOD

To examine this issue, we reviewed 248 octogenarians (mean age, 82.6 +/- 2.3 years; 58% men) who underwent primary isolated aortic valve replacement (n = 99), or aortic valve replacement and coronary revascularization (n = 149), between 1980 and 1995. Nineteen-millimeter valves were used in 26% of the patients.

RESULTS

In-hospital mortality was 8.9%, 5% for aortic valve replacement alone and 11.4% for aortic valve replacement and coronary revascularization. It was 12.5% for the 19-mm size valves compared with 7.7% for the bigger size valves (p = 0.24). Follow-up (mean interval, 4.4 years) demonstrated survival for all patients of 85%, 60%, and 30% and survival free from cardiovascular events of 80%, 45%, and 21% at 1, 5, and 10 postoperative years, respectively. Multivariate analysis identified triple-vessel disease and preoperative congestive heart failure as associated with increased risk for both in-hospital and late mortality (p < 0.05). Valve size did not influence late survival or event-free survival regardless of body surface area.

CONCLUSIONS

The use of small aortic valve prostheses in octogenarians does not adversely affect the incidence of early or late mortality or cardiac events.

Determinants of early and late results of combined valve operations and coronary artery bypass grafting

BACKGROUND

Factors determining the outcome of operative correction of valvular abnormalities combined with coronary artery bypass grafting are still incompletely defined.

METHODS

Determinants of early and late (more than 90 days) deaths and event-free survival were studied for combined valve operations and coronary artery bypass grafting in 741 patients using multivariate analysis.

RESULTS

Ninety-day survival probability was 89% (95% confidence interval, 87% to 92%). Preoperative risk factors for early death were age, female sex, renal failure, New York Heart Association class IV or V, and mitral insufficiency. The operative risk factor was the duration of aortic cross-clamping. Five- and 10-year survival probabilities were 74% (95% confidence interval, 71% to 78%) and 43% (95% confidence interval, 36% to 50%), respectively. Preoperative risk factors for late death were age, preoperative renal failure, New York Heart Association class IV or V, vessel disease, and nonsinus rhythm. Five- and 10-year event-free survival probabilities were 57% (95% confidence interval, 53% to 61%) and 23% (95% confidence interval, 17% to 28%), respectively. Preoperative risk factors for non-event-free survival were age, female sex, reduced left ventricular function, mitral regurgitation, and pacemaker rhythm.

CONCLUSION

The demographic factors of age and female sex; the comorbid condition of renal failure; the cardiac conditions of advanced New York Heart Association class, left ventricular function, mitral regurgitation, vessel disease, and cardiac rhythm; and the operative condition of ischemia time are the most important predictors of clinical outcome after combined valve operations and coronary artery bypass grafting.

Interaction of age and coronary disease after valve replacement: implications for valve selection

The interaction of patient age and the presence of coronary artery disease (CAD) and its influence on survival were examined in 3,644 patients undergoing either aortic (AVR) or mitral (MVR) valve replacement with or without coronary artery bypass grafting (CABG) between 1974 and 1991. Emergency procedures were performed much more frequently in those undergoing MVR and CABG than in those undergoing AVR and CABG (18.8% and 6.7%, respectively). The adverse effect of CAD on median survival for patients of all ages undergoing either AVR or MVR was statistically significant (AVR without CAD 11.8 versus 8.7 years with CAD; MVR without CAD 12.7 versus 7.3 years with CAD; p < 0.0001). Survival in patients younger than 70 years without CABG who underwent either AVR or MVR was quite good (< 60 years: AVR, > 14 years; MVR, 15.4 years; 60 to 69 years: AVR, 10.4 years; MVR, 11.4 years). The most profound effect of CAD on patient survival after valve replacement was observed in patients 60 to 69 years of age who underwent MVR, in whom the median survival without CABG was 11.4 years versus 5.5 years with CABG (p < 0.0001). An emergency operative status was associated with a reduced early and late survival for those patients undergoing MVR, particularly those with CAD. By relating the Cox proportional hazard models for valve survival to patient survival, we found that, in those patients 70 years and older with and without CAD who underwent either AVR or MVR, the median patient survival was reduced sufficiently (5.5 versus 8.1 years) to justify use of a bioprosthetic valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of survival and recovery of left ventricular function after aortic valve replacement

To determine factors that influence survival and recovery of ventricular function in patients undergoing aortic valve replacement in the current surgical era, baseline risk factors related to outcome were analyzed in 1,012 consecutive patients undergoing aortic valve replacement between 1983 and 1990. Forty-two percent of patients underwent concomitant coronary bypass. Observed survival probabilities (expressed as 30-day/5-year) were 0.97/0.81 overall, 0.99/0.89 for patients aged less than 70 years, and 0.95/0.74 for patients aged 70 years or greater. Advanced age (p < 0.0001), decreased ejection fraction (p < 0.0001), extent of coronary disease (p < 0.006), smaller prosthetic valve (p < 0.03), and advanced New York Heart Association class (p < 0.04) were incremental risk factors for mortality. In patients with preoperative ventricular dysfunction (ejection fraction < or = 0.45), ejection fraction measured 1.4 years after aortic valve replacement improved in 72% and the mean increment in ejection fraction was 0.175 (95% confidence interval, 0.154 to 0.195). The increment in ejection fraction was greater in female patients than in male patients (p < 0.02) and greater in patients without than with coronary disease (p < 0.02). Female sex (p < 0.02) and lesser extent of coronary disease (p < 0.05) were independent predictors of change in ejection fraction. In all patients, early improvement in ejection fraction conveyed an independent subsequent survival benefit (p < 0.0001). The results of aortic valve replacement in the current era are excellent, and the majority of patients with ventricular dysfunction demonstrate significant improvement. Early improvement in ejection fraction, influenced by coexistent coronary artery disease and sex-associated factors, importantly affects subsequent survival.

Survival and valve failure after aortic valve replacement

A prospective evaluation of 412 consecutive patients undergoing isolated aortic valve replacement between January 1982 and December 1985 was performed in an attempt to identify the determinants of survival and valve failure. A variety of valves were inserted to permit a prospective evaluation of alternative valves including: Björk-Shiley mechanical (n = 37), Ionescu-Shiley pericardial (n = 261), Hancock pericardial (n = 78), and Carpentier-Edwards porcine (n = 36). Thirteen patients died in the hospital (3.2%) and 47 patients died in the follow-up period producing an actuarial survival of 81% +/- 3% at 48 months. Survival was independently predicted by advancing age, preoperative New York Heart Association functional class, and the presence of endocarditis (p less than 0.05 by Cox regression analysis). The majority of patients were symptomatically improved (New York Heart Association class I or II: 21% preoperative, 88% postoperative). Freedom from structural valve dysfunction, prosthetic valve endocarditis, and reoperation for valve-related complications were 95% +/- 2%, 95% +/- 2%, and 92% +/- 2% at 48 months, respectively. These valve-related complications occurred more frequently in younger patients and in those with a Hancock pericardial valve (freedom from structural valve dysfunction, 89% +/- 5%; prosthetic valve endocarditis, 84% +/- 9%; reoperation, 78% +/- 10%; p less than 0.05 by Cox regression). Freedom from thromboembolism was 88% +/- 2% at 48 months; it was significantly lower in patients with a preoperative thromboembolic event and was not influenced by the type of prosthesis inserted. Freedom from anticoagulant-related hemorrhage was 85% +/- 8% at 48 months and was not influenced by any preoperative factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Patch aortotomy for aortic valve replacement after previous coronary artery bypass grafting

Exposure for aortic valve operations after previous coronary artery bypass grafting may be technically difficult owing to the presence of patent vein grafts on the proximal aorta. A patch or "island" aortotomy technique that allows excellent exposure of the aortic valve is presented here. In select patients this approach may facilitate cardioplegia administration.

Early results of aortic valve replacement with or without concomitant coronary artery bypass grafting

Early results of aortic valve replacement were reviewed in 962 unselected patients, 659 without concomitant coronary bypass surgery (AVR group) and 303 with combined valve replacement and coronary artery bypass grafting (AVR + CABG). The early (less than 30-day) mortality was 4.6% in the AVR, and 5.9% in the AVR + CABG group. Multivariate analysis showed coronary artery stenoses and NYHA functional class to be independent predictors of early mortality in the AVR group, and the number of distal anastomoses as the strongest predictor in AVR + CABG. The incidence of peroperative technical complications in the cases with fatal outcome was 27% in the AVR and 6% in the AVR + CABG group. The incidence of myocardial injury (new Q wave or evidence of increased enzyme leakage) was 11% in AVR and 21% in AVR + CABG. Independent predictors of postoperative myocardial injury were aortic cross-clamp time, year of surgery, coronary artery stenoses and NYHA class in AVR and aortic cross-clamp time and year of surgery in AVR + CABG. The study suggests that coronary artery disease increases risk in aortic valve replacement with or without CABG. Replacement should be undertaken before endstage of the disease (NYHA IV), with CABG if significant coronary disease is present, and in multivessel disease the number of distal anastomoses should be restricted in order to shorten aortic cross-clamp time.

Reoperations on heart valve prostheses: an analysis of operative risks and late results

To evaluate risks and complications of reoperations on heart valve prostheses, we reviewed data on 183 patients who underwent reoperation because of prosthetic valve malfunction. The incremental effect of the redo procedure on hospital mortality and morbidity was studied by comparing primary and reoperative procedures and analyzing a series of possible predisposing factors. Late survival after first and second reoperations was computed, and possible determinants of late mortality were examined. Overall operative mortality was 8.7%; emergency operation (p = 0.0001), previous thromboembolism (p = 0.05), and advanced New York Heart Association functional class (p = 0.031) were the independent determinants. In a series of 1,355 patients having primary or secondary isolated valve replacement, the redo procedure was a significant risk factor in the univariate analysis (p = 0.025) but not in the multivariate analysis except for the subset of patients having mitral valve replacement (p = 0.052). The postoperative course was quite complicated, as evidenced by the long mean stay in the intensive care unit (mean stay, 3.8 days; longer than 2 days for 26% of the survivors). Nevertheless, postoperative complications were not significantly greater after a redo procedure than after a primary operation. Actuarial survival at 7 years was 57.3% +/- 8%. A comparison with a nonhomogeneous series from our institution did not demonstrate significant differences. In the subset of 16 patients having a second reoperation, late survival was 37.8% +/- 16% at 2 years. Advanced New York Heart Association class (p = 0.0001), double prosthetic valve dysfunction (p = 0.003), and any indication other than primary tissue failure (p = 0.06) were determinants of late mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic valve replacement with combined myocardial revascularisation

Early and late outcome was studied in 630 patients who underwent aortic valve replacement between 1974 and 1982. Group 1 (506 patients) did not have important coronary artery disease, group 2 (69 patients) had coronary artery disease and underwent coronary artery bypass grafting, and group 3 (55 patients) had coronary artery disease but did not undergo myocardial revascularisation. Early mortality (within 30 days of operation) was significantly lower for group 1 (6%) than for group 2 (13%) and for group 3 (16%). Operative mortality in all three groups was lower in patients operated on more recently. The three year survival of patients in group 1 (83%) was significantly higher than that of patients in group 3 (62%) but not than that of patients in group 2 (76%). The findings of this study suggest that the presence of coronary artery disease increases the risk of aortic valve replacement whether or not coronary artery grafting is performed. Myocardial revascularisation, however, seems to return patients with aortic valve and coronary artery disease to a survival curve similar to that of patients with isolated aortic valve disease.