Mechanical versus biological isolated aortic valvular replacement after the age of 70: equivalent long-term results

Antithrombotic management after aortic valve replacement with biological prosthesis: a meta-analysis

BACKGROUND

We aimed to summarise the existing knowledge regarding antithrombotic medications following surgical aortic valve replacement (SAVR) using a biological valve prosthesis.

METHODS

We performed a meta-analysis of studies that reported the results of using antithrombotic medication to prevent thromboembolic events after SAVR using a biological aortic valve prosthesis and recorded the outcomes 12 months after surgery. Since no randomised controlled trials were identified, observational studies were included. The analyses were conducted separately for periods of 0-12 months and 3-12 months after surgery. A random effects model was used to calculate pooled outcome event rates and 95% confidence intervals (CIs).

RESULTS

The search yielded eight eligible observational studies covering 6727 patients overall. The lowest 0- to 12-month mortality was observed in patients with anticoagulation (2.0%, 95% CI 0.4-9.7%) and anticoagulation combined with antiplatelet therapy (2.2%, 95% CI 0.9-5.5%), and the highest was in patients without antithrombotic medication (7.3%, 95% CI 3.6-14.2%). Three months after surgery, mortality was lower in anticoagulant patients (0.5%, 95% CI 0.1-2.6%) than in antiplatelet patients (3.0%, 95% CI 1.2-7.4%) and those without antithrombotics (3.5%, 95% CI 1.3-9.3%). There was no eligible evidence of differences in stroke rates observed among medication strategies. At 0- to 12-month follow-up, all antithrombotic treatment regimens resulted in an increased bleeding rate (antiplatelet 4.2%, 95% CI 2.9-6.1%; anticoagulation 7.5%, 95% CI 3.8-14.4%; anticoagulation combined with antiplatelet therapy 8.3%, 95% CI 5.7-11.8%) compared to no antithrombotic medication (1.1%, 95% CI 0.4-3.4%). At 3- to 12-month follow-up, there was up to an eight-fold increase in the bleeding rate in patients with anticoagulation combined with antiplatelet therapy when compared to those with no antithrombotic medication. Overall, the evidence certainty was ranked as very low.

CONCLUSION

Although this meta-analysis reveals that anticoagulation therapy has a beneficial tendency in terms of mortality at 1 year after biological SAVR and suggests potential advantages in continuing anticoagulation beyond 3 months, it is limited by very low evidence certainty. The imperative for cautious interpretation and the urgent need for more robust randomised research underscore the complexity of determining optimal antithrombotic strategies in this patient population.

Aortic Valve Replacement in the Elderly

Background—

Few data exist on long-term outcomes of elderly patients after aortic valve replacement. We evaluated latest follow-up information for patients ≥70 years of age after aortic valve replacement.

Methods and Results—

Late overall survival of 2890 consecutive patients ≥70 years of age who underwent aortic valve replacement between January 1993 and December 2007 was reviewed retrospectively, analyzed, and stratified by preoperative and intraoperative variables. Observed 5-, 10-, and 15-year late postoperative survival was lower than generally expected (68%, 34%, and 8% versus 70%, 42%, and 20%, respectively; P <0.001). Independent predictors of late death included older age, renal failure, diabetes mellitus, stroke, myocardial infarction, immunosuppression, prior coronary artery bypass grafting, implanted pacemaker, lower ejection fraction, hypertension, and New York Heart Association class III or IV. After stratification by age–comorbidity risk score, 10-year survival for the lowest-risk group (n=946 [33%]) was similar to expected survival (55% versus 55%; P =0.50), but for the highest-risk group (n=564 [20%]), survival was significantly lower than expected (9% versus 26%; P <0.001). For 229 pairs of propensity-matched patients with mechanical or biological prostheses, survival was not significantly different (67%, 40%, and 19% versus 71%, 45%, and 7% at 5, 10, and 15 years, respectively; P =0.81). Structural deterioration of bioprostheses occurred in 64 patients (2.4%).

Conclusions—

Survival of elderly patients after aortic valve replacement is influenced by age and preoperative comorbidities; 33% at lowest risk had overall survival similar to that of an age- and sex-matched general population. There was no sufficient evidence that valve type affected survival. Structural deterioration of aortic bioprostheses was rare.

Midterm outcomes and quality of life of aortic root replacement: mechanical vs biological conduits

BACKGROUND

Aortic root replacement is a complex operation for severe aortic root pathology such as aneurysms and dissections with concomitant aortic valve disease. Biological and mechanical valve conduits are available.

METHODS

Early and midterm results were analyzed in patients undergoing aortic root replacement. From January 1, 1998, to May 31, 2007, 144 patients underwent aortic root replacement (Bentall procedures) with either a mechanical (n = 51) or a biological (n = 93) valve conduit. Cox proportional hazard analysis was used to determine whether valve type was an independent predictor of all-cause mortality, and analysis of covariance was used to compare general and disease-specific health-related quality-of-life scores.

RESULTS

Operative mortality was 2.1%. Median follow-up time was 40 months; 1- and 5-year survival rates for the mechanical group were 96.0% and 89.0%, respectively, vs 93.0% and 84.0% for the biological group. Valve type was not predictive of all-cause mortality, and valve-related complications were not significantly different between groups. At follow-up, 31.5% of patients in the biological group were on anticoagulant. General and disease-specific health-related quality-of-life scores were not significantly different between groups.

CONCLUSIONS

Aortic root replacement with either mechanical or biological valved conduits is a safe procedure. Morbidity, mortality, and adverse quality of life were not associated with the type of valve conduit. Further studies are required to assess long-term durability of biological valve conduits used for aortic root replacement.

Aortic valve replacement with 17-mm St. Jude Medical Regent prosthetic valves for a small calcified aortic annulus in elderly patients

PURPOSE

The aim of this study was to investigate the outcome of aortic valve replacement (AVR) performed with a 17-mm St. Jude Medical Regent prosthetic valve (17SJMR) for an aortic annulus ≤19 mm in elderly patients aged ≥65 years.

METHODS

Six female patients (age 73.0 ± 5.1 years, body surface area 1.43 ± 0.07 m²) underwent AVR between October 2005 and February 2008.

RESULTS

Peak transaortic pressure gradient, which was 80.8 ± 31.0 mmHg preoperatively, decreased to 31.0 ± 4.2 mmHg postoperatively (P < 0.01) and to 21.7 ± 1.5 mmHg long term (P < 0.01). The left ventricular mass index, which was 112.1 ± 10.6 g/m² preoperatively, also significantly decreased to 101.4 ± 15.0 g/m² postoperatively and to 88.3 ± 14.8 g/m² long term (P < 0.01). Subjective symptoms diminished in all patients, and neither mortality nor hemorrhagic complications occurred. The postoperative mean effective orifice area index was 0.91 ± 0.04 cm²/m².

CONCLUSION

A favorable outcome was obtained by aortic valve replacement with the 17SJMR. Patients showed improved postoperative hemodynamic performance without valve-related complications.

Aortic Valve Replacement With 17-mm St. Jude Medical Prostheses for a Small Aortic Root in Elderly Patients

BACKGROUND

There are few reports about the optimal prosthesis for elderly patients who have small aortic roots with an aortic annular size of less than 19 mm.

METHODS

From October 2004 to October 2006, 11 women aged 70 years or older (mean age, 74.9 +/- 3.5 years) underwent aortic valve replacement with a 17-mm Regent prosthesis (St. Jude Medical, St. Paul, MN), with the size determined using the manufacturer's sizer. Clinical status and the results of preoperative and postoperative echocardiography were evaluated.

RESULTS

The patients had a mean body surface area of 1.33 +/- 0.13 m2. Preoperative average New York Heart Association (NYHA) functional class was 2.5 +/- 0.7. Preoperative echocardiography showed a mean indexed effective orifice area of 0.33 +/- 0.14 cm2/m2 and a left ventricular mass index of 175 +/- 63 g/m2. Seven patients underwent associated procedures. Postoperative ventilation time was 14 +/- 5.6 hours, and the intensive care unit stay was 1.0 +/- 0.4 days. No patients died perioperatively. The NYHA functional class improved to class I in 9 patients. No obstruction of valve opening was observed. A significant increase in the mean indexed effective orifice area (0.87 +/- 0.10 cm2/m2) and regression of left ventricular mass index were found (114 +/- 46 cm2/m2) on postoperative echocardiography.

CONCLUSIONS

Aortic valve replacement in elderly patients with small aortic roots (less than 19 mm) using a 17-mm Regent prosthesis showed satisfactory clinical and hemodynamic results.

A 10-year comparison of explanted Hancock-II and Carpentier–Edwards supraannular bioprostheses

BACKGROUND

Bioprosthetic heart valves are more frequently being used in valve replacement procedures today. Although second-generation bioprosthetic valves have improved functionality over their first-generation counterparts, they still often fail due to primary tissue degeneration.

METHODS

This study examines two second-generation porcine valves after surgical explantation, the Hancock-II (HAN; Medtronic Heart Valve Division, Irvine, CA, USA) and the Carpentier-Edwards supraannular (CE-SAV; Baxter Healthcare Corporation, now Edwards LifeSciences, Irvine, CA, USA), with special attention to morphological/histological changes and reasons for valve failure. A total of 98 HAN and 65 CE-SAV valves were explanted and seen over a 10-year period.

RESULTS

CE-SAV valves had a longer average implant duration than HAN valves (13.9+/-3.9 years vs. 10.0+/-5.1 years). Compared with HAN valves, CE-SAV valves also had a higher incidence of stent deformation (41.5% vs. 14.3%), calcification (75.4% vs. 54.1%), and pannus (100% vs. 91.8%).

CONCLUSIONS

The greater degenerative changes seen with CE-SAV valves over HAN valves may be due to the longer implant duration of CE-SAV valves in this series. To our knowledge, the present study is the first direct morphological comparison of these two valve models.

Risk-corrected impact of mechanical versus bioprosthetic valves on long-term mortality after aortic valve replacement

OBJECTIVE

Choice of a mechanical or biologic valve in aortic valve replacement remains controversial and rotates around different complications with different time-related incidence rates. Because serious complications will always "spill over" into mortality, our aim was to perform a meta-analysis on overall mortality after aortic valve replacement from series with a maximum follow-up of at least 10 years to determine the age- and risk factor-corrected impact of currently available mechanical versus stented bioprosthetic valves.

METHODS

Following a formal study protocol, we performed a dedicated literature search of publications during 1989 to 2004 and included articles on adult aortic valve replacement with a mechanical or stented bioprosthetic valve if age, mortality statistics, and prevalences of well-known risk factors could be extracted. We used standard and robust regression analyses of the case series data with valve type as a fixed variable.

RESULTS

We could include 32 articles with 15 mechanical and 23 biologic valve series totaling 17,439 patients and 101,819 patient-years. The mechanical and biologic valve series differed in regard to mean age (58 vs 69 years), mean follow-up (6.4 vs 5.3 years), coronary artery bypass grafting (16% vs 34%), endocarditis (7% vs 2%), and overall death rate (3.99 vs 6.33 %/patient-year). Mean age of the valve series was directly related to death rate with no interaction with valve type. Death rate corrected for age, New York Heart Association classes III and IV, aortic regurgitation, and coronary artery bypass grafting left valve type with no effect. Included articles that abided by current guidelines and compared a mechanical and biologic valve found no differences in rates of thromboembolism.

CONCLUSION

There was no difference in risk factor-corrected overall death rate between mechanical or bioprosthetic aortic valves irrespective of age. Choice of prosthetic valve should therefore not be rigorously based on age alone. Risk of bioprosthetic valve degeneration in young and middle-aged patients and in the elderly and old with a long life expectancy would be an important factor because risk of stroke may primarily be related to patient factors.

The Stentless Freestyle Bioprosthesis: Impact of Age Over 80 Years on Quality of Life, Perioperative, and Mid-Term Outcome

BACKGROUND

The steadily increasing life expectancy of the population in the Western World, together with the progress in noninvasive diagnostic methods and operating techniques lead to an increase in aortic valve surgery in elderly people.

AIM OF THE STUDY

Is there an increased risk of adverse perioperative and mid-term outcome for octogenarians and do they benefit from aortic valve replacement (AVR) with stentless bioprostheses?

METHODS

Between 1996 and 2002, 503 patients older than 60 years underwent AVR with a stentless Freestyle bioprosthesis. Seventy-six of them were older than 80 years. The risk of operative mortality, perioperative complications, valve-related morbidity for octogenarians was determined by multivariate logistic regression.

RESULTS

In general, risk-adjusted analyses did not reveal an increased risk of operative mortality (p = 0.4), postoperative atrial fibrillation (p = 0.2), prolonged ventilation (p = 0.5), prolonged stay in the intensive care unit (p = 0.3), or mid-term valve-related morbidity as prosthetic valve endocarditis (p = 0.2), reoperation (p = 0.4), bleeding events (p = 0.1), and stroke (p = 0.8) for octogenarians. Continuously increasing age was an independent risk factor for postoperative neurological complications (OR = 1.8 per 10 years, p = 0.04). Quality of life was equal to or better than the general population of the same age. Median survival time of octogenarians was 5.2 +/- 0.5 years.

CONCLUSIONS

Except for postoperative neurological complications, octogenarians receiving stentless bioprostheses had no increased risk of adverse perioperative and mid-term outcome in comparison to younger patients. As quality of life and life expectancy after AVR with stentless valves were equal to the general population, AVR with stentless bioprostheses should not be withheld from octogenarians.

Mid term outcome and quality of life after aortic valve replacement in elderly people: mechanical versus stentless biological valves

OBJECTIVE

To assess the benefit for patients older than 65 years of aortic valve replacement with stentless biological heart valves in comparison with mechanical valves.

DESIGN

Multiple regression analysis of a retrospective follow up study.

SETTING

Single cardiothoracic centre.

PATIENTS

Between 1996 and 2001, 392 patients with a mean age of 74 years underwent aortic valve replacement with stentless Freestyle bioprostheses or mechanical St Jude Medical prostheses.

MAIN OUTCOME MEASURE

Operative mortality and morbidity, postoperative morbid events, mid term survival, and New York Heart Association (NYHA) class improvement, and quality of life.

RESULTS

No significant differences were found between patients receiving stentless biological valves and patients receiving mechanical prostheses. However, analysis of subgroups showed that patients older than 75 years with mechanical valves had an increased risk of major bleeding events (p = 0.007). Patients requiring anticoagulation by means of coumarin had a twofold increased risk of an impaired emotional reaction (p = 0.052). However, for patients who received a mechanical valve for severe combined aortic valve disease a survival advantage (p = 0.045) and a decreased risk of prolonged ventilation (p = 0.001) was observed. On the other hand, patients receiving a stentless bioprosthesis had an increased risk of a prolonged stay in intensive care (p = 0.04) and stroke (p = 0.01) if they had severely reduced cardiac function (NYHA class IV).

CONCLUSIONS

Elderly people receiving stentless bioprostheses benefit emotionally because of the avoidance of coumarin. However, in patients with severe hypertrophied ventricles and extraordinary calcifications, stentless bioprostheses should be chosen with caution.

Is aortic valve replacement with bileaflet prostheses still contraindicated in the elderly?

BACKGROUND

Prolonged survival in the Western world has increased the number of elderly patients referred for open-heart surgery during the last decade. Aortic valve disease is the most common heart valve disease in aged patients. Which aortic valve substitute is best employed in the elderly is still a debated matter. The main concern is about the thromboembolic and hemorrhagic risks related to mechanical valves and anticoagulation.

OBJECTIVE

The study aimed at reviewing clinical results after isolated aortic valve replacement with bileaflet prostheses in patients over 70 years and at retrospectively comparing them with those of a group of otherwise comparable patients under 50 years of age who underwent isolated aortic valve replacement with a mechanical device.

METHODS

The study population included 118 consecutive elderly patients (group A) operated on between January 1988 and January 1999 and 122 young patients (group B) who underwent aortic valve replacement during the same time period. Patients with associated coronary artery disease, mitral stenosis or regurgitation, type A aortic dissection, and infective endocarditis were excluded from the study. Preoperative clinical data, early and late postoperative mortality, all valve-related complications, and all data concerning the anticoagulation status - including the mean international normalized ratio (INR) and the mean time interval between each INR assay - were compared between the two groups.

RESULTS

The hospital mortality was significantly lower in group B (2.45%) than in group A (9.3%; p = 0.022). The mean follow-up period was 50.98 +/- 2.23 months. The 12-year actuarial survival was significantly lower (69.6 +/- 0.08%) in group A than in group B (94.4 +/- 0.02%; p < 0.001). No significant difference was found in terms of valve-related and anticoagulation-related complication rates and actuarial freedom as well as mean interval between consecutive INR checks (p = 0.219) and mean INR value (p = 0.914).

CONCLUSIONS

Bileaflet prostheses in elderly patients can achieve excellent early and late clinical results, with a low incidence of anticoagulation-related complications and an extremely low risk of a reoperation. Older age can no longer be considered a contraindication to bileaflet prosthesis implantation in the aortic position.

Long Term Clinical and Echocardiographic Results of Isolated Aortic Valve Replacement in Elderly Patients

Results after isolated aortic valve replacement with bileaflet prostheses in patients over 70 years old were reviewed.

One-hundred-twenty-eight elderly patients were operated on between January 1988 and January 2000. Patients with associated heart disease were excluded from the study. Preoperative data, early and late postoperative mortality, all valve related complications and data concerning anticoagulation status were recorded.

Hospital mortality was 9.3%. Mean follow-up time was 60.98±2.23 months. Twelve-year actuarial survival was 69.6±0.08%. Valve related and anticoagulation related complication rates (0.8% and 1.6% respectively) and actuarial freedom (99±0.009 both) were low, as well as the mean interval between consecutive INR checks (18.39±1.90 days) and the mean INR value (2.17±0.135). Late echocardiographic results showed low postoperative mean transprosthetic gradients (15.48±0.94).

Bileaftlet prostheses in the elderly can achieve excellent results with a low incidence of anticoagulation related complications and low risk of reoperation. Older age can no longer be considered a contraindication to bileaftlet prosthesis implant.

Short-term results after aortic valve replacement with stentless xenografts in elderly patients

OBJECTIVE

Our aim was to chart the short-term results of the first 75 of our patients who had undergone first-time aortic valve replacement (AVR) with stentless xenografts.

DESIGN

Our study included a complete follow-up (mean/max. 1.5/3.7 years) of the first 75 patients (42 males, 33 females; mean age 74, range 61-84 years) who underwent a first AVR with stentless xenografts.

RESULTS

Forty-three percent of patients were in functional class II and 57% in classes III-IV preoperatively. Coronary artery bypass grafting (CABG) was performed in 33 patients. Early mortality (< or = 30 days) was 6.7%, with no significant relation to CABG or age. Crude survival was 81% (95% confidence interval, CI: 71-91 %) at 3 years. Using a multivariate analysis, we identified a low left ventricular ejection fraction as a predictor of early and late mortality. Late survival (early mortality excluded) was comparable with the survival of a matched Danish background population. There were six embolic events (all cerebral: 3 minor, 1 major, 2 fatal), while two patients underwent redo-AVR because of either endocarditis (fatal) or aortic regurgitation caused by malaligned commissures. There were no other valve-related complications. Cumulative freedom was 89% (95% CI: 79-99%) for embolism and 86% (95% CI: 76-96 %) for all complications at 3 years. At the end of the study, 64% of the survivors were in functional class I, 34% were in class II and 2% in class III.

CONCLUSIONS

Considering the age composition of our patients, and compared with international results, our early mortality rates were acceptable. The absence of late excess mortality compared with the background population and the functional status at end-of-study may indicate the potential haemodynamic advantages of stentless aortic valves, at least in the short term.