Comparison of outcome after valve replacement with a bioprosthesis versus a mechanical prosthesis: initial 5 year results of a randomized trial

Mechanical or biological prosthesis for aortic valve replacement in patients aged 45 to 74 years

OBJECTIVE

The selection of valve prostheses for patients undergoing surgical aortic valve replacement remains controversial. In this study, we compared the long-term outcomes of patients undergoing aortic valve replacement with biological or mechanical aortic valve prostheses.

METHODS

We evaluated late results among 5762 patients aged 45 to 74 years who underwent biological or mechanical aortic valve replacement with or without concomitant coronary artery bypass from 1989 to 2019 at 4 medical centers. The Cox proportional hazards model was used to compare late survival; the age-dependent effect of prosthesis type on long-term survival was evaluated by an interaction term between age and prosthesis type. Incidences of stroke, major bleeding, and reoperation on the aortic valve after the index procedure were compared between prosthesis groups.

RESULTS

Overall, 61% (n = 3508) of patients received a bioprosthesis. The 30-day mortality rate was 1.7% (n = 58) in the bioprosthesis group and 1.5% (n = 34) in the mechanical group (P = .75). During a mean follow-up of 9.0 years, the adjusted risk of mortality was higher in the bioprosthesis group (hazard ratio, 1.30, P < .001). The long-term survival benefit associated with mechanical prosthesis persisted until 70 years of age. Bioprosthesis (vs mechanical prosthesis) was associated with a similar risk of stroke (P = .20), lower risk of major bleeding (P < .001), and higher risk of reoperation (P < .001).

CONCLUSIONS

Compared with bioprostheses, mechanical aortic valves are associated with a lower adjusted risk of long-term mortality in patients aged 70 years or less. Patients aged less than 70 years undergoing surgical aortic valve replacement should be informed of the potential survival benefit of mechanical valve substitutes.

Aortic Valve Replacement in Adult Patients with Decellularized Homografts: A Single-Center Experience

BACKGROUND

decellularized aortic homografts (DAH) represent a promising alternative for aortic valve replacement in young adults due to their low immunogenicity and thrombogenicity. Herein, we report our midterm, single-center experience in adult patients with non-frozen DAH from corlife.

METHODS

safety, durability, and hemodynamic performance were evaluated according to current guidelines in all consecutive patients who had received a DAH at our center since 03/2016.

RESULTS

seventy-three (mean age 47 ± 11 years, 68.4% (n = 50) male) patients were enrolled. The mean diameter of the implanted DAH was 24 ± 2 mm. Mean follow-up was 36 ± 27 months, with a maximum follow-up of 85 months and cumulative follow-up of 215 years. No cases of stenosis were observed, in four (5.5%) cases moderate aortic regurgitation occurred, but no reintervention was required. No cases of early mortality, non-structural dysfunction, reoperation, valve endocarditis, or thrombosis were observed. Freedom from bleeding and thromboembolic events was 100%; freedom from re-intervention was 100%; survival was 98.6% (n = 72).

CONCLUSIONS

early and mid-term results showed low mortality and 100% freedom from reoperation, thromboembolic events, and bleeding at our center. However, in order for this novel approach to be established as a valid alternative to aortic valve replacement in young patients, long-term data are required.

Should mitral valve replacement age guidelines be lowered due to better bioprosthetic mitral valve durability?

OBJECTIVE

Guideline recommendations for mechanical or bioprosthetic valve for mitral valve replacement by age remains controversial. We sought to determine bovine pericardial valve durability by age and risk of reintervention.

METHODS

This retrospective study between 2 large university-based cardiac surgery programs examined patients who underwent bioprosthetic mitral valve replacement from 2004 to 2020. Follow-up was obtained through June 2022. Durability outcomes involving structural valve deterioration were compared by age decile.

RESULTS

Of 1544 available patients, mean age was 66 ± 13 years and 652 (42%) were aged less than 65 years. Indications for mitral valve replacement were as follows: mitral regurgitation greater than 2+ in 53% (n = 813), mitral stenosis in 44% (n = 650), endocarditis in 18% (n = 277), and reoperation in 39% (n = 602). Concomitant procedures were aortic valve replacement in 28% (n = 426), tricuspid valve in 36% (n = 550), and coronary artery bypass in 19% (n = 290). Thirty-day mortality was 5.4%. In follow-up (clinical: median [interquartile range] 75 [25-129] months), reoperation for endocarditis and new stroke were low (0.30 and 1.06 per 100 patient/years, respectively). The cumulative incidence of mitral valve reintervention for structural valve deterioration among all patients was 6.2% at 10 years and 9.0% at 12 years with no statistical difference in structural valve deterioration in patients aged 40 to 70 years (P = .1). In 90 patients with mitral valve reintervention, 30-day mortality after reintervention was 4.7% (n = 2) for 43 with mitral valve-in-valve and 6.4% (n = 3) for 47 with reoperation.

CONCLUSIONS

Bovine pericardial mitral valve replacement is a durable option for younger patients. The opportunity to avoid anticoagulation and the associated risks with mechanical mitral valve replacement may be of benefit to patients. These insights may provide data needed to revise the current guidelines.

Mechanical versus Bioprosthetic Valve for Aortic Valve Replacement: Systematic Review and Meta-Analysis of Reconstructed Individual Participant Data

OBJECTIVES

To compare biological versus mechanical aortic valve replacement.

METHODS

We searched MEDLINE, Scopus, and Cochrane Library databases for randomized clinical trials and propensity-score matched studies published by October 14th, 2021 according to PRISMA statement. Individual patient data on overall survival were extracted. One- and two-stage survival analyses, and random-effects meta-analyses were conducted.

RESULTS

25 studies were identified, incorporating 8,721 bioprosthetic and 8,962 mechanical valves:. In the one-stage meta-analysis, mechanical valves cumulatively demonstrated decreased hazard for mortality (Hazard Ratio [HR] : 0.79, 95% Confidence interval [CI] : 0.74-0.84, p < 0.0001). Overall survival was similar between the compared arms for patients <50 years old (HR: 0.88, 95% CI : 0.71-1.1, p = 0.216), increased in the mechanical valve arm for patients 50-70 years old (HR : 0.76, 95% CI : 0.70-0.83, p < 0.0001), and increased in the bioprosthetic arm for patients >70 years old (HR : 1.35, 95% CI : 1.17-1.57, p < 0.0001). Meta-regression analysis revealed that the survival in the 50-70 years old group was not influenced by the publication year of the individual studies. No statistically significant difference was observed regarding in-hospital mortality, post-operative strokes and post-operative reoperation. All-cause mortality was found decreased in the mechanical group, cardiac mortality was comparable between the two groups, major bleeding rates were increased in the mechanical valve group, and reoperation rates were increased in the bioprosthetic valve group.

CONCLUSIONS

Survival rates seem to not be influenced by the type of prosthesis in patients <50 years old. A survival advantage in favour of mechanical valves is observed in patients 50-70 years old, while in patients >70 years old bioprosthetic valves offer better survival outcomes.

Late Outcomes of Aortic Valve Replacement with Bioprosthesis and Mechanical Prosthesis

BACKGROUND

Despite constant improvement and refinement of the prostheses, the decision between mechanical and biological valves for aortic valve replacement is still controversial.

OBJECTIVE

To compare outcomes of aortic valve replacement with bioprosthesis and mechanical prosthesis.

METHODS

This was an observational, historical cohort study with review of medical records. A total of 202 patients who underwent heart valve replacement surgery between 2004 and 2008 were selected, with a mean follow-up of 10 years. The level of significance set at 5%.

RESULTS

Mean age of patients was approximately 50 years; most patients were male (70%). Overall mortality- and reoperation-free survival was significantly higher in patients with mechanical prosthesis (HR=0.33; 95%CI=0.13-0.79; p=0.013). No difference was found in late mortality between the two groups. On the other hand, the risk of reoperation was significantly higher in patients with bioprosthesis than mechanical prosthesis (HR=0.062; 95%CI=0.008-0.457; p=0.006). The risk of composite adverse events - stroke, bleeding, endocarditis, thrombosis and paravalvular leak - was similar between the groups (HR=1.20; 95%CI= 0.74-1.93; p=0.44). The risk of bleeding was significantly higher in patients with mechanical prosthesis (HR=3.65; 95%CI= 1.43-9.29; p = 0.0064), although no case of fatal bleeding was reported.

CONCLUSION

No difference in 10-year mortality was found between the groups. The risk of reoperation significantly increases with the use of bioprosthesis, especially for patients younger than 30 years. Patients with mechanical prosthesis are at increased risk of nonfatal bleeding.

A Tale of Two Valves: Bioprosthetic Aortic Valve Obstruction in Systemic Lupus Erythematosus and Antiphospholipid Antibody Syndrome

Patients with systemic lupus erythematosus (SLE) and antiphospholipid antibody syndrome (APLAS) are at risk for cardiac manifestations, specifically valvular heart disease requiring valve replacement. Bioprosthetic valve endocarditis is an important cause of valve failure, and it is important to keep a wide differential, especially in patients with preexisting SLE and APLAS. In this E-challenge, 2 cases of bioprosthetic aortic valve endocarditis are presented; 1 case describes infective bacterial endocarditis on an aortic prosthesis and the second describes a patient with SLE and APLAS who developed bioprosthetic valve obstruction secondary to vegetations, consistent with nonbacterial endocarditis and thrombus. Etiologies for bioprosthetic valve obstruction and evaluation by echocardiography are explored. The comparison between these 2 cases specifically highlights the importance of keeping a wide differential in endocarditis, prosthetic valve vegetations, and bioprosthetic valve obstruction.

Comparison of Biological and Mechanical Prostheses for Heart Valve Surgery: A Systematic Review of Randomized Controlled Trials

Background

The choice of a mechanical (MP) or biological prosthesis (BP) for patients with valvular heart disease undergoing replacement is still not a consensus.

Objective

We aimed to determine the clinical outcomes of MP or BP placement in those patients.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared biological prostheses and mechanical prostheses in patients with valvular heart diseases and assessed the outcomes. RCTs were searched in the MEDLINE, EMBASE, LILACS, CENTRAL, SCOPUS and Web of Science (from inception to November 2014) databases. Meta-analyses were performed using inverse variance with random effects models. The GRADE system was used to rate the quality of the evidence. A P-value lower than 0.05 was considered significant.

Results

A total of four RCTs were included in the meta-analyses (1,528 patients) with follow up ranging from 2 to 20 years. Three used old generation mechanical and biological prostheses, and one used contemporary prostheses. No significant difference in mortality was found between BP and MP patients (risk ratio (RR = 1.07; 95% CI 0.99-1.15). The risk of bleeding was significantly lower in BP patients than MP patients (RR = 0.64; 95% CI 0.52-0.78); however, reoperations were significantly more frequent in BP patients (RR = 3.60; 95% CI 2.44-5.32). There were no statistically significant differences between BP and MP patients with respect to systemic arterial embolisms and infective endocarditis (RR = 0.93; 95% CI 0.66-1.31, RR = 1.21; CI95% 0.78-1.88, respectively). Results in the trials with modern and old prostheses were similar.

Conclusions

The mortality rate and the risk of thromboembolic events and endocarditis were similar between BP and MP patients. The risk of bleeding was approximately one third lower for BP patients than for MP patients, while the risk of reoperations was more than three times higher for BP patients.

A Clinical Study of Isolated Aortic Valve Replacement: A Univariate Analysis of Risk Factors

Between 1979 and 1990, 190 patients underwent isolated aortic valve replacement at Seoul National University Hospital in Korea. There were 11 (5.8%) in-hospital deaths. Univariate analysis identified advanced age (p = 0.026), preoperative serum GOT or GPT greater than 40IU/1 (p < 0.001, p = 0.003), NYHA Class III or IV (p = 0.029), preoperative mean pulmonary arterial pressure greater than 19 mmHg (p = 0.019), reoperation for aortic valve replacement (p = 0.035), second or third open heart surgery (p < 0.001), and use of mechanical valve (p = 0.008) as variables associated with increased in-hospital risk. Follow-up documented survival rates of 98.1% and 96.4% and event-free survival rates of 95.7% and 81.6% at 3 and 7 postoperative years, respectively. NYHA Class III or IV (p = 0.009), preoperative serum total bilirubin level greater than 1.2 mg/dl (p = 0.009), reoperation for aortic valve replacement (p = 0.03), second or third open heart surgery (p = 0.002), and use of mechanical valve were associated with decreased late survival and event-free survival.

Comparison of clinical outcomes in patients undergoing mitral valve replacement with mechanical or biological substitutes: a 20 years cohort

Background

The choice of prosthesis for mitral valve replacement still remains controversial. This study assessed mortality, bleeding events and reoperation in patients who underwent mitral valve replacement surgery with biological or mechanical substitutes.

Methods

A total of 352 patients who underwent mitral valve replacement surgery between 1990 and 2008 with 5 to 23 years of follow-up were retrospectively evaluated in a cohort study.

Results

The 5, 10, 15 and 20 year survival rates after surgery using a mechanical substitute were 87.7%, 74.2%, 69.3% and 69.3%, respectively, while after surgery with a biological substitute, they were 87.6%, 71.0%, 64.2% and 56.6%, respectively. There was no significant difference between the two groups (p = 0.38). In the multivariate analysis, the factors associated with death were age, bleeding events and renal failure. The probabilities of remaining free of reoperation at 5, 10, 15 and 20 years after surgery using a mechanical substitute were 94.4%, 92.7%, 92.7% and 92.7%; after surgery with a bioprosthesis, they were 95.9%, 86.4%, 81.2% and 76.5%, respectively (p = 0.073). There was a significantly higher incidence of reoperation for the bioprosthetic valve replacement group (p = 0.008). The probabilities of remaining free of bleeding events at 5, 10, 15 and 20 years after surgery using a mechanical substitute were 95.0%, 91.0%, 89.6% and 89.6%, respectively, while after surgery with a bioprosthesis, they were 96.9%, 94.0%, 94.0% and 94.0%, (p = 0.267).

Conclusions

The authors concluded that: 1) mortality during follow-up was statistically similar for both groups; 2) there was a greater tendency to reoperation in the bioprosthesis group; 3) the probability of remaining free from reoperation remained unchanged after 10 years’ follow-up for patients with mechanical substitute valves; 4) the probability of remaining fee from bleeding events remained unchanged after 10 years’ follow-up for patients given bioprostheses; 5) the baseline characteristics of patients were the greatest determinants of later mortality after surgery; 6) the type of prosthesis was not an independent predictive factor of any of the outcomes tested in the multivariate analysis.

Management of prosthetic heart valve complications

OPINION STATEMENT

With greater awareness and treatment of valvular heart disease, there are now an increasing number of patients with prosthetic heart valves. However, replacement of a diseased valve with a prosthetic valve creates the opportunity for new and unique complications that once diagnosed require specific treatments. Complications which may occur depend not only on the type of prosthesis but also are influenced by clinical factors that are important to understand and may affect treatment strategies. Tissue prostheses tend to deteriorate over time while mechanical prostheses require anticoagulation with its attendant risks. The rate of serious prosthetic heart valve complications is approximately 3 % per year. They include bleeding, systemic embolization, obstruction due to thrombus or pannus formation, patient-prosthesis mismatch, infective endocarditis, structural deterioration, prosthetic and peri-prosthetic regurgitation, and hemolysis. Importantly, the risk of prosthetic heart valve complications can be reduced by appropriate choices made at the time of surgery such as utilization of the correct prosthesis size and type. In addition, adherence to current guidelines for anticoagulation, endocarditis prophylaxis, and the timing of clinical and echocardiographic surveillance is also important to prevent complications. Should complications occur, rapid diagnosis, usually with echocardiography, is pivotal and can provide important hemodynamic as well as anatomic information critical to determining appropriate treatment and timing of surgical re-intervention if necessary. Optimal treatment of prosthetic heart valve complications remains a challenge and new treatment strategies continue to evolve.

Aortic valve replacement for patients with mild to moderate aortic stenosis undergoing coronary artery bypass surgery

Aortic valve replacement (AVR) is not normally recommended in asymptomatic patients, even if aortic stenosis is severe. However, as the population ages, an increasing number of patients with mild or moderate aortic stenosis will require coronary artery bypass grafting (CABG). In these cases, risk of "prophylactic" AVR needs to be weighed against risks of subsequent worsening of the mildly or moderately diseased aortic valve. If unoperated, aortic stenosis will worsen at an average of 6-8 mmHg per year (-0.1 cm2/year valve area), and one-quarter of such patients will require late AVR with a high operative mortality (14-24%). If AVR is performed at the time of CABG, operative risk is increased only slightly (from 1-3% to 2-6%), as are late mortality (1-2% per year) and morbidity (1-2% per year), mainly from hemorrhagic complications. Intrinsic gradients of most prosthetic valves are sufficiently low that even patients with low aortic valve gradients are likely to derive hemodynamic benefit from AVR. Thus, if there is a measurable (>20-25 mmHg) gradient across the aortic valve in a patient who requires CABG, the patient is at considerable risk for developing symptomatic aortic stenosis prior to reaching the end of expected benefit from CABG; in this case AVR should be considered. It may be reasonable in patients with very mild gradients (<25 mmHg) to defer aortic valve surgery; however, it should be noted that aortic stenosis progression is generally more rapid when the initial gradient is small.

Composite aortic valve graft replacement: mortality outcomes in a national registry

BACKGROUND

Composite aortic valve and root replacement (CVG) is a complex surgical procedure, but excellent center-specific outcomes are reported. We sought to report outcomes in a national cohort.

METHODS AND RESULTS

The United Kingdom Heart Valve Registry was interrogated for 1962 first-time CVG (and 37,102 aortic valve replacements [AVR] as a reference group) procedures from 1986 to 2004. We analyzed 30-day mortality, long-term survival (97.2% complete follow-up), and examined available risk factors for mortality using univariate and multivariate logistic regression analysis and causes of death. CVG patients were younger, received larger valve sizes and were more likely to be emergent than AVR patients. Overall 30-day mortality was 10.7% (CVG) and 3.6% (AVR). For CVG, multivariate analysis identified advanced age (> 70 years), concomitant coronary artery surgery, impaired left ventricular function, urgent or emergency status, prosthetic valve size < or = 23 mm and hospital activity volume < or = 8 procedures per annum as significant factors for 30-day mortality. Kaplan-Meier, 1-year, 5-year, 10-year and 20-year survival were 85.2%, 77.1%, 70% and 59.3%, respectively. The conditional (post-30-day) survival was similar to the AVR cohort.

CONCLUSIONS

These Registry data provide a unique national insight into CVG outcomes. After a higher initial mortality risk, CVG has equivalent conditional longer-term survival to AVR.

Short-Term and Intermediate-Term Outcomes of Aortic Root Replacement with St. Jude Mechanical Conduits and Aortic Allografts

BACKGROUND

Few studies have directly evaluated outcomes in patients undergoing aortic root replacement with St. Jude mechanical conduits or aortic allografts (ALLO), yet both approaches have been advocated. The purpose of this study was to provide a detailed description of outcomes in a large series of aortic root replacements performed with either St. Jude mechanical conduits or aortic allografts.

METHODS

A retrospective analysis was performed on 172 consecutive adult patients undergoing aortic root replacement with either St. Jude mechanical conduits (n = 73) or aortic allografts (n = 99) from January 1990 to December 2002. Maximal follow-up was 15 years, and median follow-up was 5 years.

RESULTS

Both groups were similar with regard to median age, preoperative ejection fraction, and New York Heart Association class. The aortic allograft patient group had a higher proportion (p < 0.05) of women (43% versus 18%), prior sternotomies (52% versus 26%), preoperative renal failure (9% versus 1%), and cerebrovascular disease (16% versus 4%). Operative indications for the aortic allograft group were more frequently endocarditis (29% versus 3%; p < 0.0001) and prosthetic valve dysfunction (13% versus 1%; p < 0.01), and less frequently annuloaortic ectasia (34% versus 60%; p < 0.001) or aortic dissection (3% versus 26%; p < 0.0001). Concomitant coronary artery bypass grafting or other valve surgery was performed in 30% of patients in both groups. Incidence of early postoperative complications, including bleeding, stroke, renal failure, and respiratory failure, was similar in both groups. Thirty-day mortality was 5.5% in the St. Jude mechanical conduit group and 8.1% in the aortic allograft group (p = 0.4). Unadjusted actuarial survival at 1, 5, and 10 years was 90%, 81%, 67%, and 86%, 70%, 67%, for the St. Jude mechanical conduit and aortic allograft groups, respectively (p = 0.09). Event-free survival at 1 and 5 years was similar for both groups (p = 0.4). By multivariate analysis, New York Heart Association class III or IV, emergently performed aortic root replacement, and postoperative respiratory failure, but not valve conduit type (p = 0.3), were independent predictors of mortality.

CONCLUSIONS

Aortic root replacement can be safely performed with either allograft or mechanical conduits, even in the setting of acute dissection, redo sternotomy, or endocarditis.

The real impact of randomized clinical trials in heart valve surgery

PURPOSE OF REVIEW

The aim of this article is to evaluate the findings of clinical trials in cardiac valve surgery and to determine the real impact in standard of care. Also, publications on randomized clinical trials were reviewed as to integrity and validity. Nineteen randomized clinical trials were identified in 11 areas of operative and clinical management.

RECENT DEVELOPMENTS

The Veterans Affairs and Edinburgh Heart Valve Trials confirmed the guidelines for indications for bioprostheses and mechanical prostheses. Even current prostheses have advanced technologies but the same valve-related complications determine indications. Randomized clinical trials of mechanical prostheses failed to determine prosthesis superiority. Bioprostheses of specific manufacturers contribute sub-optimal hemodynamics in small sizes. Two trials showed lack of superiority between aortic stented and stentless bioprostheses. Autografts, not allografts, are indicated for children because of structural valve deterioration of allografts. Atrial ablation surgery with concomitant mitral valve reconstruction/replacement is safe and efficacious with at least two energy sources. Minimally invasive aortic valve replacement does not provide superior results to conventional surgery. Patient-managed anticoagulation provides the most favourable thromboembolic and hemorrhagic rates with mechanical prostheses. Prosthesis sewing cuff impregnation with a bactericidal agent to reduce the incidence of prosthetic valve endocarditis was stopped because of increased incidence of major paravalvular leak requiring reoperation.

SUMMARY

Randomized clinical trials, although limited in number, have provided advancement of the standard of care. Randomized clinical trials are indicated in the management of mild to moderate ischemic mitral regurgitation and evaluation of new transcatheter technologies to conventional surgery.

Performance of bioprostheses and mechanical prostheses assessed by composites of valve-related complications to 15 years after mitral valve replacement

OBJECTIVE

Predominant concerns of patients undergoing valve replacement surgery are risks of death, stroke, antithrombotic bleeding, and reoperation related to the replacement prosthesis. The purpose of this study was to compare valve-related reoperation, morbidity (permanent impairment), and mortality between bioprostheses and mechanical prostheses for mitral valve replacement.

METHODS

Between 1982 and 1998, a total of 959 bioprostheses were implanted in 943 patients, and a total of 961 mechanical prostheses were implanted in 839 patients. Total follow-ups were 5730 years for bioprostheses and 5271 years for mechanical prostheses. Eight variables were considered as predictors of risk for the composites of valve-related complications.

RESULTS

The linearized occurrence rates for valve-related reoperation were 3.7 events/100 patient-years for bioprostheses and 0.5 events/100 patient-years for mechanical prostheses ( P < .001), with all age groups differentiated except older than 70 years. Valve-related morbidity was undifferentiated for bioprostheses and mechanical prostheses. Valve-related mortalities were 1.7 events/100 patient-years for bioprostheses and 0.7 events/100 patient-years for mechanical prostheses ( P < .001). Predictors of valve-related reoperation were age and valve type. The only predictor of valve-related morbidity was age, whereas age and valve type were predictors for valve-related mortality. Actual freedom from valve-related reoperation favored mechanical prostheses in all age groups except older than 70 years (91.7% +/- 2.0% for bioprostheses at 15 years and 96.7% +/- 1.5% at 12 years for mechanical prostheses). Actual freedom from valve-related morbidity was not different between bioprostheses and mechanical prostheses. Actual freedom from valve-related mortality favored mechanical prostheses in all groups except older than 70 years.

CONCLUSION

Comparative evaluation gives high priority in mitral valve replacement for mechanical prostheses relative to bioprostheses for freedom from valve-related reoperation and valve-related mortality but not valve-related morbidity. Freedom from valve-related reoperation and valve-related mortality favors mechanical prostheses for all age groups except older than 70 years. Valve-related morbidity, due to neurologic or functional impairments, does not differentiate between bioprostheses and mechanical prostheses.

Complications of prosthetic heart valves

Treatment of native valvular heart disease has resulted in an increasing number of patients with prosthetic valves. Although an improvement over the diseased native valve removed at surgery, prosthetic valves have suboptimal hemodynamics; mechanical valves require anticoagulation and tissue valves wear out over time. Serious complications of prosthetic valves occur at a rate of about 2% to 3% per patient-year. Complications include thromboembolism, prosthesis-patient mismatch, structural valve dysfunction, endocarditis, and hemolysis. Prosthetic valve endocarditis is a lethal disease with mortality rates of 50% to 80% even with appropriate therapy. Echocardiography now provides detailed information on valve function and hemodynamics, allowing early detection of complications. Many of these complications can be prevented by choosing the optimal valve at the time of surgery, rigorous control of anticoagulation and adherence to established anticoagulation guidelines, dental hygiene and endocarditis prophylaxis, and periodic echocardiographic monitoring by a cardiologist.

Twenty year comparison of a Bjork-Shiley mechanical heart valve with porcine bioprostheses

OBJECTIVE

To compare survival and outcome in patients receiving a mechanical or bioprosthetic heart valve prosthesis.

DESIGN

Randomised prospective trial.

SETTING

Tertiary cardiac centre.

PATIENTS

Between 1975 and 1979, patients were randomised to receive either a Bjork-Shiley or a porcine prostheses. The mitral valve was replaced in 261 patients, the aortic in 211, and both valves in 61 patients. Follow up now averages 20 years.

MAIN OUTCOME MEASURES

Death, reoperation, bleeding, embolism, and endocarditis.

RESULTS

After 20 years there was no difference in survival (Bjork-Shiley v porcine prosthesis (mean (SEM)): 25.0 (2.7)% v 22.6 (2.7)%, log rank test p = 0.39). Reoperation for valve failure was undertaken in 91 patients with porcine prostheses and in 22 with Bjork-Shiley prostheses. An analysis combining death and reoperation as end points confirmed that Bjork-Shiley patients had improved survival with the original prosthesis intact (23.5 (2.6)% v 6.7 (1.6)%, log rank test p < 0.0001); this difference became apparent after 8-10 years in patients undergoing mitral valve replacement, and after 12-14 years in those undergoing aortic valve replacement. Major bleeding was more common in Bjork-Shiley patients (40.7 (5.4)% v 27.9 (8.4)% after 20 years, p = 0.008), but there was no significant difference in major embolism or endocarditis.

CONCLUSIONS

Survival with an intact valve is better among patients with the Bjork-Shiley spherical tilting disc prosthesis than with a porcine prosthesis but there is an attendant increased risk of bleeding.

Twenty-year comparison of tissue and mechanical valve replacement

OBJECTIVE

We sought to compare outcomes with tissue and St Jude Medical mechanical valves over a 20-year period.

METHODS

Valve-related events and overall survival were analyzed in 2533 patients 18 years of age or older undergoing initial aortic, mitral, or combined aortic and mitral (double) valve replacement with a tissue valve (Hancock, Carpentier-Edwards porcine, or Carpentier-Edwards pericardial) or a St Jude Medical mechanical valve. Total follow-up was 13,390 patient-years. There were 666 St Jude Medical aortic valve replacements, 723 tissue aortic valve replacements, 513 St Jude Medical mitral valve replacements, 402 tissue mitral valve replacements, 161 St Jude Medical double valve replacements, and 68 tissue double valve replacements. The mean age was 68 +/- 13.3 years (St Jude Medical valve, 64.5 +/- 12.9; tissue valve, 72.0 +/- 12.6).

RESULTS

There were no overall differences in survival between tissue and mechanical valves. Multivariable analysis indicated that the type of valve did not affect survival. Analysis by age less than 65 years or 65 years or older and presence or absence of coronary disease revealed similar long-term survival in all subgroups. The risk of hemorrhage was lower in patients receiving tissue aortic valve replacements but was not significantly different in patients receiving mitral valve or double valve replacements. Thromboembolism rates were similar for tissue and mechanical valve recipients. However, reoperation rates were significantly higher in patients receiving both aortic and mitral tissue valves. The reoperation hazard increased progressively with time both in patients receiving aortic and in those receiving mitral tissue valves. Overall valve complications were initially higher with mechanical aortic valves but not with mechanical mitral valves. However, valve complication rates later crossed over, with higher rates in tissue valve recipients after 7 years in patients undergoing mitral valve replacement and 10 years in those undergoing aortic valve replacement.

CONCLUSIONS

Tissue and mechanical valve recipients have similar survival over 20 years of follow-up. The primary tradeoff is an increased risk of hemorrhage in patients receiving mechanical aortic valve replacements and an increased risk of late reoperation in all patients receiving tissue valve replacements. The risk of tissue valve reoperation increases progressively with time.

Comparison of bioprosthesis and mechanical valves, a meta-analysis of randomised clinical trials

The main purpose of this meta-analysis was to compare the outcomes of patients who randomly received mechanical valves or bioprosthesis, over a long-term clinical follow-up. We found only three trials meeting our selection criteria with a total of 1229 patients (8069. 5 patient-yr). Bleeding was more frequent in patients with mechanical prostheses both after 5 yr (RR=2.6; IC=[1.9;3.5]; P<0.0001) and 11 yr (RR=1.6; IC=[1.2;2.2]; P<0.001) of follow-up. However, the increased risk of bleeding at 11 yr was only statistically significant with mechanical prostheses in the aortic position (RR=1.93; IC=[1.36;2. 74]; P=0.0002). Reoperation was significantly more frequent in patients with bioprosthesis after 11 yr follow-up (RR=0.4; IC=[0.3;0. 6]; P<0.001). Endocarditis was more frequent after 11 yr (RR=0.6; IC=[0.3;0.95]; P<0.05) in patients with mechanical prostheses but these results were heterogeneous between mitral and aortic valves. The choice of valve type does not significantly influence survival.

Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial

OBJECTIVES

The goal of this study was to compare long-term survival and valve-related complications between bioprosthetic and mechanical heart valves.

BACKGROUND

Different heart valves may have different patient outcomes.

METHODS

Five hundred seventy-five patients undergoing single aortic valve replacement (AVR) or mitral valve replacement (MVR) at 13 VA medical centers were randomized to receive a bioprosthetic or mechanical valve.

RESULTS

By survival analysis at 15 years, all-cause mortality after AVR was lower with the mechanical valve versus bioprosthesis (66% vs. 79%, p = 0.02) but not after MVR. Primary valve failure occurred mainly in patients <65 years of age (bioprosthesis vs. mechanical, 26% vs. 0%, p < 0.001 for AVR and 44% vs. 4%, p = 0.0001 for MVR), and in patients > or =65 years after AVR, primary valve failure in bioprosthesis versus mechanical valve was 9 +/- 6% versus 0%, p = 0.16. Reoperation was significantly higher for bioprosthetic AVR (p = 0.004). Bleeding occurred more frequently in patients with mechanical valve. There were no statistically significant differences for other complications, including thromboembolism and all valve-related complications between the two randomized groups.

CONCLUSIONS

At 15 years, patients undergoing AVR had a better survival with a mechanical valve than with a bioprosthetic valve, largely because primary valve failure was virtually absent with mechanical valve. Primary valve failure was greater with bioprosthesis, both for AVR and MVR, and occurred at a much higher rate in those aged <65 years; in those aged > or =65 years, primary valve failure after AVR was not significantly different between bioprosthesis and mechanical valve. Reoperation was more common for AVR with bioprosthesis. Thromboembolism rates were similar in the two valve prostheses, but bleeding was more common with a mechanical valve.

Mortality and need for reoperation in patients with mild-to-moderate asymptomatic aortic valve disease undergoing coronary artery bypass graft alone

BACKGROUND

Patients presenting for coronary artery bypass graft (CABG) surgery may have concurrent asymptomatic aortic stenosis (AS) or aortic insufficiency (AI). This retrospective study was performed to evaluate outcomes in patients with aortic valve disease undergoing CABG with or without aortic valve replacement (AVR).

METHODS

Study groups included 414 patients undergoing combined AVR and CABG (AVR-CABG group) and 62 patients with asymptomatic mild-to-moderate AS, AI, or both undergoing CABG but not AVR (CABG group). End points included 30-day mortality rate, time to cardiac mortality, time to all-cause mortality, and time to aortic valve reoperation. Reoperation refers to surgery for replacement of the native aortic valve in the CABG group or replacement of the prosthetic aortic valve in the AVR-CABG group. Important patient characteristics affecting outcomes were determined by using Cox proportional-hazard analysis. These variables were then included in multivariable analyses by using logistic regression analysis and Cox proportional-hazard modeling to compare outcomes between each patient group.

RESULTS

No difference was seen in any of the mortality end points between the CABG group and the AVR-CABG group after controlling for significant differences between the groups. However, the need for reoperation for AVR was significantly higher for the CABG group than the AVR-CABG group. For patients followed for up to 6 years, the estimated need for aortic valve reoperation was 24.3% in the CABG group versus 3% in the AVR-CABG group.

CONCLUSION

On the basis of these results, patients with asymptomatic AS or AI should be considered for AVR at the time of CABG.

Choosing a prosthetic heart valve

Although most of the available prosthetic heart valves function remarkably well, the variety of available choices attests to the inability of any single one to fulfill the requirements of the ideal valve substitute. The mechanical prostheses include the caged-ball, tilting-disc, and bileaflet valves. Tissue valves available in the United States are the Carpentier-Edwards and Hancock porcine heterograft valves and the Carpentier-Edwards pericardial valve. Review of several large comparative studies on valve performance reveals that the overall results with tissue and mechanical valves are about equal at the end of 10 years. The characteristics of each type of valve substitute dictate the selection of one prosthesis in preference to others for a particular patient. Mechanical prostheses are recommended for patients without contraindications for anticoagulants. Tissue valves are reserved for patients over 65 years of age or for patients in whom anticoagulation is contraindicated. Multiple other patient-related factors need to be considered in selecting the appropriate valve, including the psychosocial situation and patient preference.

MRI-radiofrequency tissue tagging in patients with aortic insufficiency before and after operation

BACKGROUND

Magnetic resonance imaging tissue tagging is a relatively recent methodology that describes ventricular systolic function in terms of intramyocardial ventricular deformation. Because the analysis involves the use of many intramyocardial points to describe systolic deformation, it is theoretically more sensitive at describing subtle differences in regional myocardial fiber shortening when compared with conventional measures of ventricular function such as wall thickening. The objectives of this study were (1) to define sensitive indices of ventricular systolic deformation to assist the clinician in the surgical evaluation of patients with aortic insufficiency, and (2) to quantify differences in regional systolic deformation before and after surgery for aortic insufficiency.

METHODS

Magnetic resonance imaging with tissue tagging was performed on 10 normal volunteers and 8 patients with chronic severe aortic insufficiency. Follow-up postoperative studies (5.4+/-1.1 months) were obtained in 6 patients who underwent Ross procedure (1 patient), David procedure (1), and St. Jude aortic valve replacement (4).

RESULTS

There was no significant difference in fractional area change, overall circumferential shortening, or overall radial thickening among the normal group, the preoperative aortic insufficiency group, or the postoperative aortic insufficiency group. However, on a regional basis, there was a decrease in posterior wall circumferential strains in the postoperative aortic insufficiency group (29%+/-13% preoperative aortic insufficiency (n=6) versus 24%+/-12% postoperative aortic insufficiency (n=6), p=0.02).

CONCLUSIONS

On regional analysis, there was a small but significant decrease in posterior wall circumferential shortening after operation. Magnetic resonance imaging tissue tagging is a sensitive and clinically applicable method of quantifying regional ventricular wall function before and after intervention for aortic insufficiency.

Influence of coronary artery bypass and age on clinical performance after aortic and mitral valve replacement with biological and mechanical prostheses

The influence of prosthetic type, age, and coronary artery bypass grafting (CABG) on valve-related complications by valve position was evaluated in a population of 2353 bioprosthesis patients (mean age, 66.5 years; range, 13 to 89 years) and in a population of 1112 mechanical prosthesis patients (mean age, 59.1 years; range, 13 to 91 years). The follow-up was complete to 96% and 98%, respectively, for the bioprosthesis and mechanical prosthesis groups. The patient groups were evaluated by actuarial assessment of survival and valve complications and composites. Preoperative factors were evaluated for determination of significant independent predictors by multivariate proportional-hazard regression analysis. CABG was an influential factor in the actuarial analysis. Survival was superior for aortic mechanical replacements without CABG and for mitral replacements, both biological and mechanical, without CABG (P < .05). The freedom from thromboembolism (TE) and antithromboembolic hemorrhage (ATH) was greater for biological prostheses with and without CABG for aortic replacements (P < .05) but not for mitral replacements (P = NS). The freedom from valve-related mortality was not influenced by CABG for either position (P = NS). The freedom from valve-related reoperation was greater for biological prostheses with CABG than without CABG for both aortic and mitral replacements (P < .05). The evaluation of covariates as independent predictors revealed CABG to be a nonpredictor for aortic valve replacement (AVR) (P = NS) but a predictor of survival and valve-related reoperation for mitral valve replacement (MVR) (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of outcomes in men 11 years after heart-valve replacement with a mechanical valve or bioprosthesis. Veterans Affairs Cooperative Study on Valvular Heart Disease

BACKGROUND

Mechanical heart valves are durable but thrombogenic, and their use requires that the patient receive anticoagulants. In contrast, bioprosthetic valves are less thrombogenic, but they have limited durability because of tissue deterioration.

METHODS

To compare the outcomes of patients who receive these two types of valves, we randomly assigned 575 men scheduled to undergo aortic-valve or mitral-valve replacement to receive either a mechanical or a bioprosthetic valve. The primary end points were death from any cause and any valve-related complication.

RESULTS

During an average follow-up of 11 years, there was no difference between the two groups in the probability of death from any cause (11-year probability for mechanical valves, 0.57; for bioprostheses, 0.62; P = 0.57) or in the probability of any valve-related complication (0.65 and 0.69, respectively; P = 0.39). There was a much higher rate of structural valve failure among patients who received bioprosthetic valves (11-year probability, 0.15 for the aortic valves and 0.36 for the mitral valves) than among those who received mechanical valves (no valve failures; P < 0.001). However, this difference was offset by a higher rate of bleeding complications among patients with mechanical valves than among those with bioprosthetic valves (11-year probability, 0.42 and 0.26, respectively; P < 0.001) and by a greater frequency of peri-prosthetic valvular regurgitation among patients with mechanical mitral valves than among those with mitral bioprostheses (11-year probability, 0.17 and 0.09, respectively; P = 0.05).

CONCLUSIONS

After 11 years, the rates of survival and freedom from all valve-related complications were similar for patients who received mechanical heart valves and those who received bioprosthetic heart valves. However, structural failure was observed only with the bioprosthetic valves, whereas bleeding complications were more frequent among patients who received mechanical valves.

Modern cardiac valve devices--bioprostheses and mechanical prostheses: state of the art

The choice of bioprostheses and mechanical prostheses as valvular substitutes for cardiac valve replacement surgery has existed for over 20 years. The extensive developments over the past three decades have been introduced to reduce or eliminate valve related complications, namely thromboembolism, anticoagulant related hemorrhage, and structural failure, as well as to optimize hemodynamic performance. The biological valvular prostheses, namely porcine aortic or bovine pericardium, have been developed with tissue preservation, together with stent designs, that contribute to preservation of anatomical characteristics and biomechanical properties of the leaflets. The mechanical prostheses have been developed to eliminate structural failure, to facilitate prevention of blood status and thrombus formation, to facilitate radiopacity for evaluation of prosthesis function, and to facilitate intraoperative leaflet positioning. The implantation of the various present generation bioprostheses and mechanical prostheses requires special considerations to avoid technical complications and support ventricular performance. The studies of biological and mechanical prostheses, both randomized and nonrandomized, as well as specific prosthesis assessments, have contributed to the establishment of indications for types of prostheses. Bioprostheses have a high risk of structural failure and reoperation, while mechanical prostheses have a high risk of thromboembolism and anticoagulant hemorrhage. Within the bioprostheses population, the risk factors for structural valve deterioration are younger age and mitral prosthesis. Older patients (> 65 years of age) have a greater risk of valve related complications with mechanical prostheses, while younger patients (< 40 years of age) are at greater risk with bioprostheses. Comparison of large bioprostheses and mechanical prostheses populations by age groups revealed that regardless of the differences in the freedom from structural valve deterioration, the freedom from treatment failure (valve related mortality and permanent impairment from thromboembolism, anticoagulant hemorrhage, and septal emboli from prosthetic valve endocarditis) is essentially the same for mechanical prostheses and bioprostheses at 10 years. The quality of life is superior with bioprostheses, while patient survival and total valve related morbidity/mortality are similar with both types of prostheses.

Long-term echocardiographic Doppler monitoring of Hancock bioprostheses in the mitral valve position

Echocardiographic and Doppler studies were performed in 134 patients with a Hancock bioprosthesis in the mitral valve position during a follow-up period of 1 to 216 months. Among the xenografts, 57% were clinically normal and 43% had severe dysfunction. Among the normal bioprostheses, 35% had echocardiographically thickened mitral cusps (> or = 3 mm) with normal hemodynamic function; by setting the lower 95% confidence limit of valve area at 1.7 cm2 these patients had a significantly (p < 0.01) smaller valve area than that of normal control subjects. Evaluation of all thickened normal mitral valves showed the highest incidence of thickening at 9 years after implantation. Valve replacement surgery was subsequently performed in 33 patients with dysfunctioning bioprosthetic and echocardiographic diagnosis was confirmed in 91% of explanted valves (bioprosthetic stenosis 21%, incompetence 46%, and combined stenosis and regurgitation 33%). In 2 valves that were found to be stenotic on echocardiographic examination, a calcium-related commissural tear was also observed at reoperation, and in another, a paravalvular leak was found. Dystrophic calcification, isolated (64%) or occasionally associated with fibrous tissue overgrowth (21%), was the main cause of failure. Pannus was present in prostheses with longer satisfactory function (168 +/- 31 vs 124 +/- 21 months; p < 0.001). Long-term performance was evaluated by the Kaplan-Meier method for up to 18 years of follow-up. Freedom from structural valvular disfunction after mitral replacement was 89% at 6 years, 77% at 8 years, 56% at 10 years, 31% at 12 years, 16% at 15 years, and 15% at 18 years.

Twelve-year comparison of a Bjork-Shiley mechanical heart valve with porcine bioprostheses

BACKGROUND

Patients undergoing heart-valve replacement may receive a mechanical prosthesis, necessitating lifelong anticoagulant treatment, or a porcine bioprosthesis, which involves no absolute need for anticoagulants.

METHODS

We carried out a randomized, prospective trial to compare the durability of the Bjork-Shiley mechanical prosthesis (spherical tilting-disk model) and the incidence of valve-related complications with those variables in the Hancock and the Carpentier-Edwards porcine prostheses. The mitral valve was replaced in 261 patients, the aortic valve in 211, and both in 61; the survivors have been followed up for a mean of 12 years.

RESULTS

We found a trend toward improved actuarial survival after 12 years with the Bjork-Shiley prosthesis, but this trend was not statistically significant (group with Bjork-Shiley valve vs. group with porcine valve [mean +/- SE], 51.5 +/- 3.2 vs. 44.4 +/- 3.2 percent; P = 0.08). There was no significant difference in the actuarial incidence of reoperation after 5 years, but after 12 years significantly more patients with a porcine prosthesis had undergone reoperation (8.5 +/- 2.0 vs. 37.1 +/- 4.1 percent, P less than 0.001). An analysis combining death and reoperation as end points for an actuarial assessment of survival with the original prosthesis intact confirmed that the patients with Bjork-Shiley Shiley prostheses had improved survival (48.6 +/- 3.2 vs. 30.0 +/- 3.0 percent after 12 years, P less than 0.001). Bleeding requiring hospitalization or blood transfusion was significantly more frequent in the patients with Bjork-Shiley prostheses (18.6 +/- 3.2 vs. 7.1 +/- 2.3 percent after 12 years, P less than 0.01). There was no significant difference after 12 years in the actuarial occurrence of embolism (Bjork-Shiley vs. porcine, 21.1 +/- 3.1 vs. 26.4 +/- 3.5 percent) or endocarditis (3.7 +/- 1.4 vs 4.6 +/- 1.6 percent).

CONCLUSIONS

Survival with an intact valve is better among patients with the Bjork-Shiley spherical tilting-disk prosthesis than among patients with porcine bioprostheses, but use of the Bjork-Shiley valve carries an attendant increased risk of bleeding associated with the need for anticoagulant treatment.

Progressive functional deterioration of bioprostheses assessed by Doppler ultrasonography

Doppler echocardiography was used to study the function of bioprosthetic heart valves by noninvasive means in 32 patients aged 29 to 72 years at various postoperative intervals. There were 24 Ionescu-Shiley, four Hancock, and four Carpentier-Edwards prostheses, 19 in the aortic and 13 in the mitral position. Initial studies were performed at a mean of 2.3 years after implantation and were repeated one, two, and three years thereafter. Flow velocities in the mitral orifice, left ventricular outflow tract, and ascending aorta, as well as mitral pressure half-time, were measured from pulsed-wave or continuous-wave Doppler recordings. Mitral and aortic valve areas and aortic pressure gradients were calculated. In aortic prostheses the valve area decreased and pressure gradient increased progressively in relation to the time from implantation. The mean value (+/- SD) of the aortic valve area was 67 +/- 17 percent of the manufacturer's nominal value at the first examination and 57 +/- 20 percent one year later, 51 +/- 14 percent two years later, and 46 +/- 11 percent three years later (overall differences, p less than 0.01). In mitral prostheses, reduction of the valve area was not related to the time from implantation. The mean mitral valve area was 45 +/- 12 percent of the nominal value at rest and increased to 68 +/- 18 percent during exercise at a mean of 45 months after implantation. There was no change in these values at the one-year repeat study. It is concluded that in a population with predominantly pericardial bioprostheses, (1) aortic tissue prostheses showed a progressive functional deterioration demonstrable by Doppler echocardiography, most probably due to degenerative changes; and (2) in mitral tissue prostheses, there was no significant reduction of orifice area in relation to time from implantation. Reduction of mitral valve areas may, to some extent, reflect a less than full opening at rest.

Case-matched comparison of mitral valve replacement and repair

Carpentier's techniques of prosthetic ring mitral valve repair for mitral regurgitation offer the potential for immediate and long-term improvement in valve function without the necessity of replacing the native valve with a prosthesis. A consecutive, case-matched series of 65 patients with prosthetic ring mitral valve repair was compared with 65 patients undergoing mitral valve replacement for mitral regurgitation. The aortic cross-clamp time was 57 +/- 33 minutes in the repair operations and 41 +/- 25 minutes in the replacement operations (p = 0.003). The cardiopulmonary bypass time was 154 +/- 44 minutes in the repair operations and 113 +/- 41 minutes in the replacement operations (p = 0.0001). There were no myocardial infarctions in the hospital in either group. Hospital death was noted in 1.5% of repairs and 4.6% of replacements (p = not significant). Survival at 4 years was 0.84 for repairs and 0.82 for replacements (p = not significant). Freedom from reoperation to replace the mitral valve at 4 years was 62 of 65 patients in the repair group and 64 of 65 patients in the replacement group (p = not significant). In-hospital and midterm results in a closely matched population show that mitral valve repair yields results comparable with those of replacement despite a more difficult procedure. The benefits of maintaining the native valve with chordal and papillary muscle structure intact and avoidance of prosthetic valve implantation may then become apparent with longer follow-up.

Determinants of survival and left ventricular performance after mitral valve replacement. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease

To determine how survival and clinical status were related to left ventricular (LV) size and systolic function after mitral valve replacement, 104 patients (48 mitral regurgitation [MR], 33 mitral stenosis [MS], and 23 MS/MR) with isolated mitral valve replacement were evaluated before and after surgery. Preoperative hemodynamic abnormalities by cardiac catheterization were improved 6 months after surgery in all three patient groups. The patients with MR exhibited reductions in LV end-diastolic volume index (EDVI) (117 +/- 51 to 89 +/- 27 ml/m2, p less than 0.001) and ejection fraction (EF) (0.56 +/- 0.15 to 0.45 +/- 0.13, p less than 0.001); however, the ratio of forward stroke volume to end-diastolic volume increased (0.32 +/- 0.21 to 0.45 +/- 0.17, p less than 0.001) because of the elimination of regurgitant volume. Survival analysis revealed that mortality was significantly higher in MS or MS/MR patients with postoperative EDVI more than 101 ml/m2 (p less than 0.001 and p less than 0.042, respectively) and in MR patients with postoperative EF less than or equal to 0.50 (p less than 0.031). Also, the majority of patients with MR or MS/MR and postoperative EDVI more than 101 ml/m2 and EF less than or equal to 0.50 were in New York Heart Association class III or IV. Multivariate logistic regression analysis in the patients with MR revealed that the strongest predictor of postoperative EF was preoperative EF (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Left atrial dimension and risk of systemic embolism in patients with a prosthetic heart valve. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease

The relation between left atrial dimension measured by M-mode echocardiography and systemic embolization after valve replacement was examined prospectively among 397 patients with a prosthetic valve enrolled in the Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Baseline characteristics including several measures of left atrial enlargement were compared for 31 patients who developed systemic embolism and 366 who did not develop embolism during a 5 year follow-up period. Variables that were significantly related to left atrial dimension or systemic embolization in univariate analyses were included with several others in a multiple logistic regression model. The incidence rate of systemic embolism was more than three times higher after mitral valve replacement than after aortic valve replacement (4.4 and 1.3 per 100 patient-years, respectively); this difference persisted after adjustment for other factors. Univariate analysis indicated a threefold higher incidence of systemic embolism in patients with a left atrial dimension greater than or equal to 4 cm compared with that in patients with a dimension less than 4 cm (3 versus 1 per 100 patient-years, respectively). However, when the effect of valve location (mitral versus aortic) was taken into account using either univariate or multivariate techniques, left atrial dimension was found not to be associated with systemic embolism. In multivariate analysis, atrial fibrillation, age, ejection fraction and location of the prosthetic valve were significantly associated with embolism. Results of this multicenter study suggest that left atrial dimension is not independently related to the development of systemic embolism in patients undergoing valve replacement.