Long-term performance of heart valve prostheses

Perspective on the cost-effectiveness of transapical aortic valve implantation in high-risk patients: Outcomes of a decision-analytic model

BACKGROUND

The incremental cost-effectiveness of transapical transcatheter aortic valve implantation (TAVI) is ill-defined in high-risk patients where aortic valve replacement (AVR) is an option, and has not been ascertained outside a randomized controlled trial.

METHODS

We developed a Markov model to examine the progression of patients between health states, defined as peri- and post-procedural, post-complication, and death. The mean and variance of risks, transition probabilities, utilities and cost of transapical TAVI, high-risk AVR, and medical management were derived from analysis of relevant registries. Outcome and cost were derived from 10,000 simulations. Sensitivity analyses further evaluated the impact of mortality, stroke, and other commonly observed outcomes.

RESULTS

In the reference case, both transapical TAVI and high-risk AVR and TAVI were cost-effective when compared to medical management ($44,384/QALY and $42,637/QALY, respectively). Transapical TAVI failed to meet accepted criteria for incremental cost-effectiveness relative to AVR, which was the dominant strategy. In sensitivity analyses, the mortality rates related to the two strategies, the utilities post-AVR and post-transapical TAVI, and the cost of transapical TAVI, were the main drivers of model outcome.

CONCLUSION

Transapical TAVI did not satisfy current metrics of incremental cost-effectiveness relative to high-risk AVR in the reference case. However, it may provide net health benefits at acceptable cost in selected high-risk patients among whom AVR is the standard intervention.

Early acute thrombosis of bioprosthetic mitral valve presenting with cardiogenic shock

Early thrombosis of bioprosthetic mitral valves is an extremely rare occurrence. We present an unusual case of a patient with polycythemia presenting with cardiogenic shock, secondary to acute thrombosis of a bioprosthetic mitral valve which was placed 14 months prior to presentation. Our report also reviews predisposing factors and treatment options for bioprosthetic mitral valve thrombosis.

Markov model for selection of aortic valve replacement versus transcatheter aortic valve implantation (without replacement) in high-risk patients

Comparisons between transcatheter aortic valve implantation without replacement (TAVI) and tissue aortic valve replacement (AVR) in clinical trials might not reflect the outcomes in standard clinical practice. This could have important implications for the relative cost-effectiveness of these alternatives for management of severe aortic stenosis in high-risk patients for whom surgery is an option. The mean and variance of risks, transition probabilities, utilities, and cost of TAVI, AVR, and medical management derived from observational studies were entered into a Markov model that examined the progression of patients between relevant health states. The outcomes and cost were derived from 10,000 simulations. Sensitivity analyses were based on variations in the likelihood of mortality, stroke, and other commonly observed outcomes. Both TAVI and AVR were cost-effective compared to medical management. In the reference case (age 80 years, the perioperative TAVI and AVR mortality was 6.9% vs 9.8%, and annual mortality was 21% vs 24%), the utility of TAVI was greater than that of AVR (1.78 vs 1.72 quality-adjusted life years) and the lifetime cost of TAVI exceeded that of AVR ($59,503 vs $56,339). The incremental cost-effectiveness ratio was $52,773/quality-adjusted life years. Threshold analyses showed that variation in the probabilities of perioperative and annual mortality after AVR and after TAVI and annual stroke after TAVI were important determinants of the favored strategy. Sensitivity analyses defined the thresholds at which TAVI or AVR was the preferred strategy with regard to health outcomes and cost. In conclusion, TAVI satisfies current metrics of cost-effectiveness relative to AVR and might provide net health benefits at acceptable cost for selected high-risk patients among whom AVR is the current procedure of choice.

Clinical event rates with the On-X bileaflet mechanical heart valve: a multicenter experience with follow-up to 12 years

OBJECTIVE

The aim of the study was to establish clinical event rates for the On-X bileaflet mechanical heart valve (On-X Life Technologies Inc, Austin, Tex) using an audit of data from the 3 centers within Europe with the longest history of implanting.

METHODS

All patients receiving the On-X valve between March 1, 1998, and June 30, 2009, at 3 European centers were studied. Data were collected using questionnaire and telephone surveys augmented by outpatient visits and examination of clinical records.

RESULTS

There were 691 patients, with a mean age of 60.3 years, who received 761 valves in total: 407 mitral valve replacements, 214 aortic valve replacements, and 70 aortic + mitral valve replacements (dual valve replacement). Total follow-up was 3595 patient-years, with a mean of 5.2 years (range, 0-12.6 years). Early (≤ 30 days) mortality was 5.4% (mitral valve replacement), 0.9% (aortic valve replacement), and 4.3% (dual valve replacement). Linearized late (>30 days) mortality expressed per patient-year was 3.6% (mitral valve replacement), 2.2% (aortic valve replacement), and 4.1% (dual valve replacement), of which valve-related mortality was 0.5% (mitral valve replacement), 0.2% (aortic valve replacement), and 1.8% (dual valve replacement). Late linearized thromboembolism rates were 1.0% (mitral valve replacement), 0.6% (aortic valve replacement), 1.8% (dual valve replacement). Bleeding rates were 1.0% (mitral valve replacement), 0.4% (aortic valve replacement), and 0.9% (dual valve replacement). Thrombosis rates were 0.1% (mitral valve replacement), 0% (aortic valve replacement), and 0.3% (dual valve replacement). Reoperation rates were 0.6% (mitral valve replacement), 0.2% (aortic valve replacement), and 1.2% (dual valve replacement).

CONCLUSIONS

The On-X valve has low adverse clinical event rates in longer-term follow-up (mean 5.2 years and maximum 12.6 years).

Aortic valve replacement combined with the endoventricular patch technique for aortic valve stenosis complicated by ischemic heart disease

The indication for aortic valve replacement (AVR) combined left ventricular (LV) plasty in the patient with aortic valve stenosis (AS) complicated by ischemic heart disease is controversial. We describe a case of AS with ischemic heart disease of a patient who underwent a successful surgical treatment, AVR combined with the endoventricular patch technique. The patient was an 82-year-old woman who suffered from heart failure, New York Heart Association (NYHA) class III. The heart failure derived from AS and ischemic heart disease with severely compromised LV function. She underwent AVR combined with the endoventricular patch technique and the postoperative course was uneventful. She has been well with NYHA class I for about 5 years after the operation without heart failure.

Quality-of-Life Implications of Immediate Surgery and Watchful Waiting in Asymptomatic Aortic Stenosis

Background—

Traditional management of severe aortic stenosis (AS) is based on delay in aortic valve replacement (AVR) until the development of symptoms. Surgery for asymptomatic AS has been proposed to reduce the small risk of sudden death before AVR and avoid heart failure (HF) after AVR. Because a trial to compare these options is unlikely, we developed a Markov model to inform the choice between immediate surgery and watchful waiting in asymptomatic AS.

Methods and Results—

We defined health states as preoperative, postoperative, postcomplication, and death. We calculated the implications of watchful waiting, tissue and mechanical AVR-based on risks, transitions, utilities, and cost derived from literature review. Further analyses evaluated situations thought to favor immediate surgery and watchful waiting. Sensitivity analyses were based on the likelihood of preoperative death and HF in follow-up. In the reference case (age, 65 years; post-AVR utility, 0.9; annualized pre-AVR mortality, 1%; and post-AVR HF, 11.3%), the utility of watchful waiting was superior to that of immediate mechanical or tissue AVR (quality-adjusted life-years, 7.4 versus 5.3 versus 5.3, respectively), and the cost was less than immediate surgery. Sensitivity analyses showed immediate surgery was not likely to be more effective regardless of the yearly probability of post-AVR HF in the watchful waiting group (range, 0% to 80%). Immediate surgery was likely to be effective when pre-AVR annual mortality reached 13%.

Conclusions—

Immediate surgery in asymptomatic severe AS does not improve outcomes unless risk of sudden death pre-AVR and HF after AVR are higher than currently reported.

Antithrombotic medication for cardioembolic stroke prevention

Embolism of cardiac origin accounts for about 20% of ischemic strokes. Nonvalvular atrial fibrillation is the most frequent cause of cardioembolic stroke. Approximately 1% of population is affected by atrial fibrillation, and its prevalence is growing with ageing in the modern world. Strokes due to cardioembolism are in general severe and prone to early recurrence and have a higher long-term risk of recurrence and mortality. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke. Anticoagulation therapy's associated risk of hemorrhage and monitoring requirements have encouraged the investigation of alternative therapies for individuals with atrial fibrillation. New anticoagulants being tested for prevention of stroke are low-molecular-weight heparins (LMWH), unfractionated heparin, factor Xa inhibitors, or direct thrombin inhibitors like dabigatran etexilate and rivaroxaban. The later exhibit stable pharmacokinetics obviating the need for coagulation monitoring or dose titration, and they lack clinically significant food or drug interaction. Moreover, they offer another potential that includes fixed dosing, oral administration, and rapid onset of action. There are several concerns regarding potential harm, including an increased risk for hepatotoxicity, clinically significant bleeding, and acute coronary events. Therefore, additional trials and postmarketing surveillance will be needed.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Aortic valve disease and treatment: the need for naturally engineered solutions

The aortic valve regulates unidirectional flow of oxygenated blood to the myocardium and arterial system. The natural anatomical geometry and microstructural complexity ensures biomechanically and hemodynamically efficient function. The compliant cusps are populated with unique cell phenotypes that continually remodel tissue for long-term durability within an extremely demanding mechanical environment. Alteration from normal valve homeostasis arises from genetic and microenvironmental (mechanical) sources, which lead to congenital and/or premature structural degeneration. Aortic valve stenosis pathobiology shares some features of atherosclerosis, but its final calcification endpoint is distinct. Despite its broad and significant clinical significance, very little is known about the mechanisms of normal valve mechanobiology and mechanisms of disease. This is reflected in the paucity of predictive diagnostic tools, early stage interventional strategies, and stagnation in regenerative medicine innovation. Tissue engineering has unique potential for aortic valve disease therapy, but overcoming current design pitfalls will require even more multidisciplinary effort. This review summarizes the latest advancements in aortic valve research and highlights important future directions.

Hancock II bioprosthesis for aortic valve replacement: the gold standard of bioprosthetic valves durability?

BACKGROUND

This study examined the long-term durability of the Hancock II bioprosthesis (Medtronic, Minneapolis, MN) in the aortic position.

METHODS

From 1982 to 2004, 1134 patients underwent aortic valve replacement (AVR) with Hancock II bioprosthesis and were prospectively monitored. Mean patient age was 67 +/- 11 years; 202 patients were younger than 60, 402 were 60 to 70, and 526 were older than 70. Median follow-up was 12.2 years and 99.2% complete. Valve function was assessed in 94% of patients. Freedom from adverse events was estimated by the Kaplan-Meier method.

RESULTS

Survival at 20 and 25 years was 19.2% +/- 2% and 6.7% +/- 2.8%, respectively, with only 34 and 3 patients at risk. Survival at 20 years was 54.9% +/- 6.4% in patients younger than 60 years, 22.7% +/- 3.3% in those 60 to 70, and 2.4% +/- 1.9% in those older than 70 (p = 0.01). Structural valve deterioration developed in 67 patients aged younger than 60, in 18 patients aged 60 to 70, and in 2 patients older than 70. The freedom from structural valve deterioration at 20 years was 63.4% +/- 4.2% in the entire cohort, 29.2% +/- 5.7% in patients younger than 60 years, 85.2% +/- 3.7% in patients aged 60 to 70, and 99.8% +/- 0.2% in patients older than 70 (truncated at 18 years). Repeat AVR was performed in 104 patients (74 for structural valve failure, 16 for endocarditis, and 14 for other reasons). At 20 years, the overall freedom from AVR was 65.1% +/- 4% for any reason, 29.8% +/- 5.4% in patients younger than 60 years, 86.8% +/- 3.3% in patients 60 to 70, and 98.3% +/- 0.6% in patients older than 70.

CONCLUSIONS

Hancock II bioprosthesis is a very durable valve in patients 60 years and older and is probably the gold standard of bioprosthetic valve durability in this patient population.

Choice of prosthetic heart valve in adults an update

In the last 7 years, more data have reconfirmed that patients' comorbid conditions are very important factors determining patient outcomes. Prosthetic heart valves (PHVs) that require aortic root replacement in the absence of aortic root disease are associated with poorer outcomes. For the vast majority of patients, the choice of PHV is between a mechanical valve and a stented bioprosthesis. The choice is largely dependent upon the age of the patient at the time of PHV implantation and on which complication the patient wants to avoid: specifically, anticoagulation therapy and its complications with the mechanical valve, and structural valve deterioration with a bioprosthesis. Data on the pros and cons of the choices and exceptions to the rules are discussed, and a new algorithm is developed.

Surgical treatment of active native aortic valve endocarditis with allografts and mechanical prostheses

BACKGROUND

Surgical intervention for persistent active native aortic valve endocarditis (NVE) remains challenging. We analyzed our combined experience with allografts and mechanical prostheses (MP) in NVE operations.

METHODS

Between 1980 and 2002, 138 patients (81% males) underwent aortic valve replacement for NVE in 2 centers (106 allografts; 32 MPs). Perioperative characteristics and early and late morbidity and mortality were analyzed.

RESULTS

Mean age was 47 years (range, 14 to 76 years), and 34% required emergency surgery. Abscess rate was 38% for allografts vs 18% for MPs. Concomitant mitral valve replacement was required in 38% MP patients and in 5% allograft patients. Hospital mortality was 8% (n = 11; p = 0.25): 10 allograft patients (9%) and 1 MP patient (3%). During a mean 8-year follow-up (range, 0 to 25 years) 33 patients died: 22 allograft (24%) and 11 MP patients (21%; p = 0.14). Survival at 15 years was 59% +/- 6% for allograft patients and 66% +/- 9% for MP patients (p = 0.68). Late recurrent endocarditis developed in 6 allograft patients and 1 MP patient (p = 0.29). Overall 15-year freedom from reoperation was 76% +/- 9% for allografts and 93% +/- 6% for MPs (p = 0.02).

CONCLUSIONS

Mechanical prostheses have comparable rates of midterm survival and freedom from recurrent infection. However, this is in combination with extensive excision of destructive tissue in a specific patient subset. Allograft reoperation rates increase with time. The importance of the mechanical prosthesis in NVE might be established in the coming years.

Antithrombotic management of patients with prosthetic heart valves: current evidence and future trends

Over 4 million people worldwide have received a prosthetic heart valve, and an estimated 300,000 valves are being implanted every year. Prosthetic heart valves improve quality of life and survival of patients with severe valvular heart disease, but the need for antithrombotic therapy to prevent thrombotic complications in valve recipients poses challenges for clinicians and patients. Here, we review antithrombotic therapies for patients with prosthetic heart valves and management of thromboembolic complications. Advances in antithrombotic therapy and valve technologies are likely to improve the management of patients with prosthetic heart valves in developed countries, but the most important unmet need and potential for benefit from these new therapies is in developing countries where a massive and rapidly increasing burden of valvular heart disease exists.

Fluid dynamics studies of cardiovascular medical devices and blood damage prediction

The implantation of cardiovascular devices such as prosthetic heart valves, even though very common in the clinical domain, is still not free from complications. Thromboembolic events and hemolysis are the major clinical problems that can occur, upon implantation. In this paper, we analyze the role of the particular fluid dynamics associated to such devices, in relation to the clinical outcome. A major issue, still debated, is the way to correlate the experimental findings with blood damage. The availability of advanced techniques such as LDA or PIV is necessary to evaluate the hemodynamical performance of a given implantable device at the local level and to draw reliable conclusions about potentially adverse clinical effects.

The Ross Procedure

Background— Reports on outcome after the Ross procedure are limited by small study size and show variable durability results. A systematic review of evidence on outcome after the Ross procedure may improve insight into outcome and potential determinants.

Methods and Results— A systematic review of reports published from January 2000 to January 2008 on outcome after the Ross procedure was undertaken. Thirty-nine articles meeting the inclusion criteria were allocated to 3 categories: (1) consecutive series, (2) adult patient series, and (3) pediatric patient series. With the use of an inverse variance approach, pooled morbidity and mortality rates were obtained. Pooled early mortality for consecutive, adult, and pediatric patients series was 3.0% (95% confidence interval [CI], 1.8 to 4.9), 3.2% (95% CI, 1.5 to 6.6), and 4.2% (95% CI, 1.4 to 11.5). Autograft deterioration rates were 1.15% (95% CI, 1.06 to 2.06), 0.78% (95% CI, 0.43 to 1.40), and 1.38%/patient-year (95% CI, 0.68 to 2.80), respectively, and for right ventricular outflow tract conduit were 0.91% (95% CI, 0.56 to 1.47), 0.55% (95% CI, 0.26 to 1.17), and 1.60%/patient-year (95% CI, 0.84 to 3.05), respectively. For studies with mean patient age >18 years versus mean patient age ≤18 years, pooled autograft and right ventricular outflow tract deterioration rates were 1.14% (95% CI, 0.83 to 1.57) versus 1.69% (95% CI, 1.02 to 2.79) and 0.65% (95% CI, 0.41 to 1.02) versus 1.66%/patient-year (95% CI, 0.98 to 2.82), respectively.

Conclusions— The Ross procedure provides satisfactory results for both children and young adults. Durability limitations become apparent by the end of the first postoperative decade, in particular in younger patients.

Durability of bioprosthetic cardiac valves

INTRODUCTION

The choice of type of heart valve prosthesis is determined by the patient's age since bioprostheses have a limited lifespan. This article reviews current recommendations and the literature on cardiac valve replacement.

METHODS

Selective literature search in Medline/PubMed back to 1996 and review of current national and international recommendations from specialist societies.

RESULTS

The recommendations guiding the type of heart valve replacement have been revised in recent years. Of particular interest are the new generation of biological prostheses with extended durability, a growing use of stentless bioprostheses, a decrease in mortality of reoperation and an increase in life expectancy. Comorbidities such as chronic renal insufficiency or chronic atrial fibrillation are no longer contraindications to bioprosthesis. The number of heart valve replacements in recent years rose despite a concomitant increase in valve repairs. Aortic valves are being increasingly replaced by bioprostheses.

DISCUSSION

The choice of heart valve prosthesis should be tailored to each patient taking into account the patient's age, life expectancy, comorbidities, and life style. Different decisions may be made now than those based on earlier recommendations resulting in an individualized treatment, in patients over the age of 65 or 70.

Usefulness of microsimulation to translate valve performance into patient outcome: Patient prognosis after aortic valve replacement with the Carpentier–Edwards supra-annular valve

OBJECTIVE

Numerous reports have been published documenting the results of aortic valve replacement. It is often not easy to translate these outcomes involving the condition of the valve into the actual consequences for the patient. We previously developed an alternative method to study outcome after aortic valve replacement that allows direct estimation of patient outcome after aortic valve replacement: microsimulation modeling. The goal of this article is to provide insight into microsimulation methodology and to give an overview of the advantages and disadvantages of simulation methods (in particular microsimulation) in comparison with standard methods of outcome analysis.

METHODS

By using a primary dataset containing 1847 patients and 14,429 patient-years, advantages and disadvantages of standard methods of outcome analysis are discussed, and the potential role of microsimulation is illustrated by means of a step-by-step explanation of building, testing, and using such a model.

RESULTS

Total life expectancy, event-free life expectancy, and reoperation-free life expectancy for a 65-year-old male patient were 10.6 years, 9.2 years, and 9.8 years, respectively. Lifetime risk of reoperation due to structural valve deterioration was 13.3%.

CONCLUSIONS

Microsimulation is capable of providing accurate estimates of age-related life expectancy and lifetime risk of reoperation for patients who underwent aortic valve replacement with the Carpentier-Edwards supra-annular valve. It provides a useful tool to facilitate and optimize the choice for a specific heart valve prosthesis in a particular patient.

Stentless valves for aortic valve replacement: where do we stand?

PURPOSE OF REVIEW

Following more than a decade's experience with stentless valves and the development of better profiled stented valves, the article discusses the advantages of stentless valves regarding hemodynamic performance, left ventricular mass regression, durability and survival.

RECENT FINDINGS

Recent studies show that stentless valves remain hemodynamically superior compared with modern porcine stented valves. This superiority is, however, rarely reported in comparison with modern pericardial stented valves. In general, patient-prosthesis mismatch is less frequent in stentless vs. stented valves. Recent randomized trials comparing stentless valves and modern stented valves show equivalent left ventricular mass regression at 1 year. At 10 years, stentless valve durability is excellent and comparable with that of stented valves. Recent comparative studies do not confirm the previously reported midterm survival advantages of stentless valves.

SUMMARY

Improvement of stented valves has significantly reduced the hemodynamic differences between them and their stentless counterpart. Patients with small aortic annulus, however, should benefit from a stentless valve due to the better expected gradients and lower risk of patient-prosthesis mismatch. Midterm results suggest equivalent durability and survival for both prosthesis types but additional and longer-term trials are necessary to confirm these results.

Myocardial T1 mapping for detection of left ventricular myocardial fibrosis in chronic aortic regurgitation: pilot study

OBJECTIVE

The aim of this study was to identify diffuse myocardial fibrosis secondary to chronic aortic regurgitation by comparing the T1 relaxation times of left ventricular myocardium in a pilot patient group with a previously established normal range of times.

SUBJECTS AND METHODS

Eight patients with chronic aortic regurgitation and normal coronary arteries awaiting surgical valve replacement underwent a comprehensive MRI examination that included assessment of left ventricular function, severity of valvular regurgitation, and presence of overt myocardial scar evidenced by delayed enhancement. For each patient, myocardial T1 relaxation times determined with a modified Look-Locker technique before and after contrast administration were compared with values previously established for 15 healthy volunteers.

RESULTS

There was no statistical difference (p > 0.05) in slice-averaged myocardial T1 relaxation times either before or after gadolinium administration in the patient group compared with the normal range of times. Segmental averaged T1 relaxation times in segments with abnormal wall motion did, however, show statistically significant differences from healthy controls 10, 15, and 20 minutes after administration of gadolinium (510 vs 476 milliseconds, p = 0.001; 532 vs 501 milliseconds, p = 0.002; 560 vs 516 milliseconds, p = 0.001, respectively). Two of the aortic regurgitation patients also had focal areas of myocardial delayed enhancement.

CONCLUSION

Segment-based myocardial T1 mapping has the potential for showing differences between relaxation times in aortic regurgitation and in normal hearts, suggesting the existence of a diffuse myocardial fibrotic process.

Prosthetic heart valves: Objective Performance Criteria versus randomized clinical trial

The current Food and Drug Administration (FDA) heart valve guidance document uses an objective performance criteria (OPC) methodology to evaluate the clinical performance of prosthetic heart valves. OPC are essentially historical controls, but they have turned out to be an adequate, and perhaps optimal, study design in this situation. Heart valves have a simple open-and-close mechanism, device effectiveness is easy to document, and the common complications (thromboembolism, thrombosis, bleeding, leak, and infection) are well known and easily detected. Thus, randomized clinical trials (RCTs) have not been deemed necessary for the regulatory approval of prosthetic heart valves. The OPC are derived from the average complication rates of all approved heart valves. Studies based on OPC have been shown to work well; many different valve models have gained FDA market approval based on this methodology. Although heart valve RCTs are not required by the FDA, they have been done to compare valves or treatment regimens after approval. Recently, the Artificial Valve Endocarditis Reduction Trial (AVERT) was designed to compare a new Silzone sewing ring, designed to reduce infection, with the Standard sewing ring on a St. Jude Medical heart valve. This was the largest heart valve RCT ever proposed (4,400 valve patients, followed for as long as 4 years), but it was stopped prematurely because of a high leak rate associated with the Silzone valve. Examining the results showed that a much smaller, OPC-based study with 800 patient-years would have been sufficient to disclose this complication of the Silzone valve.

Clinical results of Hancock II versus Hancock Standard at long-term follow-up

OBJECTIVE

We performed a multi-institutional study to compare the long-term structural valve deterioration of isolated Hancock Standard versus Hancock II bioprostheses.

METHODS

From 1983 to 2002, 714 Hancock Standard and 1293 Hancock II bioprostheses were implanted at hospitals of the Venetian territory (Padova, Treviso, and Venice). Follow-up on January 1, 2003, included 14,749 patient-years with a median of 12 years and was 96% complete: 115 Hancock Standard and 53 Hancock II bioprostheses were at risk at 15 years. The 2 series were nonconcomitant, and many covariates differed (Table 1). Survival was analyzed with Cox analysis, and durability was analyzed with Weibull analysis. Balancing analysis with the logistic propensity score model was performed.

RESULTS

Perioperative mortality was 6% in Hancock II and 12% in Hancock Standard operations. The overall unadjusted 15-year survival was identical (39.7% +/- 2.3% vs 39.9% +/- 2.4%, respectively), but age-adjusted survival at 15 years was 46% versus 25% (P < .001). Late survival was unrelated to the prosthetic model, whereas it was adversely affected by older age, previous operations, aortic regurgitation, male sex, higher New York Heart Association class, atrial fibrillation, and coronary artery bypass grafting. In Hancock II patients aged 65 years and older, the cumulative hazard of structural valve deterioration at 15 years was 6%, versus 17.5% in Hancock Standard patients. In younger patients, it was 18% and 37%, respectively. Analysis of 541 propensity-balanced patients showed a hazard ratio of the Hancock Standard prosthesis of 2 and a risk reduction of older age of approximately 10% every 10 years.

CONCLUSION

After balancing risk factors and calibrating age effects, Hancock II propensity-matched bioprostheses showed similar survival but definitely increased durability.

Fifteen-year results with the Hancock II valve: A multicenter experience

OBJECTIVES

The purpose of this multi-institutional study was to review the 15-year outcome of patients who received isolated aortic or mitral valve replacement with the Hancock II bioprosthesis.

METHODS

From 1983 through 2002, 1274 patients underwent 1293 isolated valve replacements, 809 aortic valve replacements and 484 mitral valve replacements, at hospitals in the Venetian area (Padova, Treviso, and Venice). Mean age was 68 +/- 8 years in patients undergoing aortic valve replacement and 66 +/- 9 years in patients undergoing mitral valve replacement; 52% of patients undergoing aortic valve replacement and 63% of patients undergoing mitral valve replacement were in New York Heart Association class III or greater. Coronary artery disease was present in 32% of patients who had undergone aortic valve replacement and 18% of patients who had undergone mitral valve replacement. Follow-up included 8520 patient-years, with a median of 12 years, and was 97% complete.

RESULTS

Overall 15-year survival was 39.7% +/- 2.4%, similar in both the aortic and mitral positions. Multivariable analysis of late survival showed the incremental risk of male sex, higher New York Heart Association class, coronary artery disease, and mitral position. Freedom from embolism was higher in the aortic position (81% +/- 2.9% in aortic vs 72% +/- 4.7% in mitral valve replacements). Freedom from endocarditis was similar in the aortic and mitral position (95% +/- 1.2% vs 94% +/- 1.7%). Freedom from reoperation (82% +/- 3.7% vs 71% +/- 5.0%) and from valve-related morbidity-mortality (52% +/- 3.6% vs 36% +/- 4.4%) was higher in patients who had undergone AVR. Actual freedom from structural valve deterioration for patients 60 years and older who had undergone aortic valve replacement was 96.5% +/- 1.3% versus 88% +/- 3.2% for patients who had undergone mitral valve replacement and 70% +/- 7.5% versus 77.5% +/- 5.3%, respectively, in younger patients. Multivariable Weibull analysis showed structural valve deterioration related to younger age and preoperative valve incompetence and inversely related to coronary artery disease.

CONCLUSION

Optimal 15-year durability can be expected in male patients 60 years and older who have undergone aortic valve replacement and in male patients 65 years and older who have undergone mitral valve replacement, extending safely the age limits for the use of this valve.

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.

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

OBJECTIVE

This study was conducted to compare the composites of valve-related complications, namely reoperation, morbidity (defined as permanent neurologic or other functional impairment), and mortality, between bioprostheses and mechanical prostheses for aortic valve replacement.

METHODS

Between 1982 and 1998, 2195 bioprostheses were implanted in 2179 patients and 980 mechanical prostheses were implanted in 883 patients. Total follow-up was 16,442 years and 5740 years for bioprostheses and mechanical prostheses, respectively. Eight variables were considered as predictors of risk for the composites of valve-related complications.

RESULTS

Linearized rates for valve-related reoperation were 1.3%/patient-year and 0.3%/patient-year for bioprostheses and mechanical prostheses (P < .001), respectively. All age groups were differentiated, except >70 years. Valve-related morbidity was differentiated for all age groups and overall, for bioprostheses and mechanical protheses, was 0.4 %/patient-year and 2.1%/patient-year, respectively (P < .001). Overall valve-related mortality was 1.0%/patient-year for bioprostheses and 0.7%/patient-year for mechanical prostheses (P = .018). Age and valve-type were predictive risk factors for reoperation and morbidity, whereas age alone was predictive of mortality. Actual freedom from valve-related reoperation favored mechanical prostheses for all age groups, except 61-70 years and >70 years. Actual freedom from valve-related morbidity favored bioprostheses in all age groups, except < or =40 years. Actual freedom from valve-related mortality was undifferentiated in patients 51-60, 61-70, and >70 years.

CONCLUSION

No differences were observed in valve-related reoperation and mortality in patients >60 years. Comparative evaluation gives high priority for bioprostheses in patients >60 years based on improved morbidity profile. This evaluation extends this center's recommendation for bioprostheses in aortic valve replacement to include patients >60 years.

Percutaneous closure of prosthetic paravalvular leaks: Case series and review

BACKGROUND

Paravalvular leaks (PVLs) are a well-recognized complication of prosthetic valve replacement. Most are asymptomatic and benign, but some may cause symptoms due to a large regurgitant volume or hemolysis. Medical therapy is palliative, while reoperation carries significant morbidity and mortality. Percutaneous transcatheter closure techniques, now routinely applied in the management of pathological cardiac and vascular communications, may be adaptable to PVL closure, potentially offer symptomatic relief.

METHODS

We reviewed our experience with attempted percutaneous closure of PVLs, using data from medical and procedural records.

RESULTS

Between 2001 and 2004, 14 procedures were performed in 10 patients, all under general anesthesia, with transesophageal and radiographic guidance. Mitral (9) and aortic (1) valve replacements were involved, both mechanical and bioprosthetic. A variety of devices were used, including atrial septal occluders, patent ductus arteriosus occluders, and coils (all of label use). Six had a single procedure, which was technically successful in four: in two, the PVL could not be crossed. Four underwent a second procedure, which was technically successful in three; in one the previously deployed device was dislodged necessitating urgent, but ultimately uneventful, surgical removal and leak repair. One patient had transient severe hemolysis, which resolved after 1 week. At 1-year follow-up (9/10 pts) three had died, five had sustained symptomatic improvement while 1 patient with a residual leak still required regular blood transfusions.

CONCLUSIONS

Percutaneous closure of PVLs is time-consuming but feasible in selected patients, with a reasonable degree of technical and clinical success. A second procedure may be necessary and a variety of complications can occur.

[Surgery for patients with mechanical heart valves--adjustment and tailoring of anticoagulant therapy]

Valvular surgery in patients (pts) with long history of cardiac valve disease is accomplishing improvement of symptoms, functional status and longevity. The numbers are very big also in our country. Our census numbers are not reliable, but estimation of above 15000 pts with prosthetic heart valve implants is close to correct. Since significant increase in survival and longevity of those pts, the possibility and necessity for non cardiac operative procedures are also increased. Because of specificity and complex constant regular anticoagulation therapy in order to prevent catastrophic prosthetic valve thrombosis and common thromboembolic complication good, but safe reduction of anticoagulation status to accomplish also safe haemostatic condition necessary for all surgical procedures. Individual adjustment and tailoring of anticoagulant and anti aggregation therapies according to accepted international protocols should be carefully done with necessery variation depending on the non cardiac organ and system involved: urgent either minor or major surgical interventions; bleeding peptic ulcer; elective surgery including ophtalmic and common dental procedures with risk of bleeding.

Prognosis After Aortic Valve Replacement With the Carpentier-Edwards Pericardial Valve: Use of Microsimulation

BACKGROUND

The second-generation Carpentier-Edwards pericardial valve (Edwards Lifesciences LLC, Irvine, CA) is widely used for aortic valve replacement. However, knowledge on the long-term outcomes of patients after valve implantation is incomplete. We used microsimulation to calculate the long-term outcome of any given patient after aortic valve replacement with the Carpentier-Edwards pericardial valve.

METHODS

A meta-analysis of 8 reports on aortic valve replacement with the Carpentier-Edwards pericardial valve (2,685 patients; 12,250 patient years) was used to estimate the hazards of valve-related events other than structural valvular deterioration. Structural valvular deterioration was described by age-dependent Weibull curves calculated from 18-year follow-up, premarket approval, Carpentier-Edwards pericardial primary data. These estimates provided the input data for the parameters of the microsimulation model, which was then used to calculate the outcomes of patients of different ages after valve implantation. The model estimates of survival were validated using two external data sets.

RESULTS

The Weibull analysis estimated a median time to reoperation for structural valvular deterioration ranging from 18.1 years for a 55-year-old male to 23.2 years for a 75-year-old male. For a 65-year-old male, microsimulation calculated a life expectancy and event-free life expectancy of 10.8 and 9.1 years, respectively. The lifetime risk of at least one valve-related event was 38% and that of reoperation due to structural valvular deterioration 17%, respectively, for this patient. The model estimates of survival showed good agreement with external data.

CONCLUSIONS

Microsimulation provides detailed insight into the long-term prognosis of patients after aortic valve replacement. The Carpentier-Edwards pericardial valve performs satisfactorily and offers a low lifetime risk of reoperation due to structural valvular deterioration, especially for elderly patients requiring aortic valve replacement.

Recommendations for the management of patients after heart valve surgery

Approximately 50,000 valve replacement operations take place in Europe annually and almost as many valve repair procedures. Previous European guidelines on management of patients after valve surgery were last published in 1995 and were limited to recommendations about antithrombotic prophylaxis. American guidelines covering the broader topic of the investigation and treatment of patients with valve disease were published in 1998 but devoted relatively little space to post-surgical management. This document represents the consensus view of a committee drawn from three European Society of Cardiology (ESC) Working Groups (WG): the WG on Valvular Heart Disease, the WG on Thrombosis, and the WG on Rehabilitation and Exercise Physiology. In almost all areas of patient management after valve surgery, randomized trials and meta-analyses do not exist. Such randomized trials as do exist are very few in number, are narrowly focused with small numbers, have limited general applicability, and do not lend themselves to meta-analysis because of widely divergent methodologies and different patient characteristics. Recommendations are therefore almost entirely based on non-randomized studies and relevant basic science.

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.