Estimated event-free life expectancy after autograft aortic root replacement in adults

Allografts for aortic valve and root replacement: veni vidi vici?

Allografts were introduced in the early 1960s for the replacement of the aortic valve and regarded at the time as a close-to-perfect valve substitute. However, over the past 40 years it has become evident that not all of the high expectations could be met. This review summarizes the past 40 years of clinical experience with allografts for aortic valve replacement, describes the advantages and disadvantages of allografts compared with other aortic valve substitutes and their impact on patient prognosis, and discusses the future role of allografts for the replacement of the aortic valve or root.

Is a bicuspid aortic valve a risk factor for adverse outcome after an autograft procedure?

BACKGROUND

Recently, bicuspid aortic valve disease is posed to be a possible risk factor for dilatation of the pulmonary autograft.

METHODS

Analysis of all 123 patients in our prospective cohort with their native aortic valve in situ at the autograft procedure.

RESULTS

The bicuspid aortic valve group (n = 81) had more males (p = 0.05), prior cardiac surgery (p = 0.02), prior aortic valve balloon dilatation (p = 0.01), aortic stenosis (p = 0.03), and less deterioration of left ventricular function (p = 0.02) than the tricuspid group (n = 42). Hospital mortality occurred in 3 patients (bicuspid 2, tricuspid 1). The follow-up was 99% complete (median, 5.3 years; SD, 3.5; range, 0.1 to 13.4) with a total of 674 patient years. During follow-up 4 patients died (bicuspid 2, tricuspid 2). Overall survival was 95% (95% confidence interval [CI], 89% to 98%) at 5 and 10 years. Seven patients required reoperation for autograft failure, all structural. Freedom from autograft reintervention was 97% (95% CI, 92% to 100%) at 5 years and 89% (95% CI, 79% to 98%) at 10 years. There were no differences in outcome between the groups. Four patients required reoperation for allograft failure, all structural. Freedom from allograft reoperation was 99% (95% CI, 97% to 100%) at 5 years and 91% (95% CI, 82% to 100%) at 10 years. There was no difference between the groups.

CONCLUSIONS

An autograft procedure in patients with a bicuspid aortic valve is justified. Bicuspid aortic valve disease is not a contraindication for an autograft procedure. Patients with a bicuspid aortic valve will meet the limitations of the autograft procedure in the same frequency as the overall autograft population.

Aortic valve repair for aortic insufficiency in adults: a contemporary review and comparison with replacement techniques

In evaluating the goal of aortic valve preservation, there have been 11 reports of large series of aortic valve repair for aortic insufficiency in adults published in recent years. We sought to analyze the validity of these methods and compare them to published results for bioprosthetic valves, pulmonary autografts, and aortic homografts. From 1990 to 2002, 761 adult aortic valve repairs were reported. Perioperative morbidity ranged from 3.6 to 23% (mean 14%), early mortality 0-8% (mean 3.6%), and late mortality 0-8% (mean 2.8%). The 5- and 10-year freedom from reoperation rates for repair were 89 and 64%. Although early results are good, long-term analysis suggests that, as a group, the durability of repair is unclear. Patients with rheumatic valvular disease appear to have an increased incidence of recurrence and repair failure. Although suture line dehiscence continues to be both an early and late complication with repair, the long-term morbidity and mortality is low and valve repair may be an option in carefully selected patients. However, the inability to break down the results by techniques does not allow for a definitive conclusion. Further subanalysis is necessary as larger series are reported. Proponents must attempt to separate successful from unsuccessful techniques. Aortic valve repair is a technique in evolution.

Prognosis after aortic root replacement with cryopreserved allografts in adults

BACKGROUND

Aortic root replacement with cryopreserved allografts is associated with excellent hemodynamics, little endocarditis, low thromboembolic event rates, and no need for anticoagulation. There is, however, concern regarding the long-term durability of this valve substitute, especially in younger patients. Meta-analysis and microsimulation were used to calculate age-specific long-term prognosis after allograft aortic root replacement based on current evidence.

METHODS

Our center's experience with cryopreserved allograft aortic root replacement in 165 adult patients was combined in a meta-analysis with reported and individual results from four other hospitals. Using this information, the microsimulation model predicted age- and gender-specific total and reoperation-free and event-free life expectancy.

RESULTS

The pooled results comprised 629 patients with a total follow-up of 1860 patient-years (range 0 to 12.8 years). Annual risks were 0.6% for thromboembolism, 0.05% for bleeding, 0.5% for endocarditis, and 0.5% for nonstructural valve failure. Structural allograft failure requiring reoperation occurred in 15 patients, and a patient age-specific Weibull function was constructed accordingly. Calculated total life expectancy varied from 27 years in a 25-year-old to 12 years in a 65-year-old male; corresponding actual lifetime risk of reoperation was 89% and 35%, respectively.

CONCLUSIONS

Cryopreserved aortic allografts have an age-related limited durability. This results in a considerable lifetime risk of reoperation, especially in young patients. The combination of meta-analysis and microsimulation provides an appropriate tool for estimating individualized long-term outcome after aortic valve replacement and can be useful both for patient counseling and prognostic research purposes.

Evolution of allograft aortic valve replacement over 13 years: results of 275 procedures

OBJECTIVE

We describe our center's experience with the use of allografts for aortic valve or root replacement, illustrating the impact on outcome of the changes made in surgical and preservation techniques.

METHODS

Between 4/1987 and 1/2001 275 allografts were used in 267 consecutive patients to replace the aortic valve or root. All patients were prospectively followed over time. Mean patient age was 46 years (SD 16; range 0.06-83), male/female ratio was 201/74. Prior cardiac operations took place in 73 patients; 49 patients presented with active endocarditis. Pre-operative NYHA-class was III in 51%. Initially, the subcoronary technique was used (SC; N=95) while in recent years root replacement (ARR; N=180) became the technique of choice. Seven fresh (two pulmonary and five aortic) and 268 cryopreserved (four pulmonary and 264 aortic; 35 glycerol and 233 DMSO) allografts were implanted. Concomitant procedures took place in 133 (48%).

RESULTS

Operative mortality was 5.5% (N=15) and during follow-up (99% complete) 29 more patients died. Overall cumulative survival was 73% (95% CI 65-81%) at 9 years postoperative and significantly better for SC compared to ARR patients (P=0.005). Freedom from allograft-related reoperation (N=34) was 77% (95% CI 69-85) at 9 years, and worse in the SC compared to ARR group due to increased early technical failure (P=0.03). Freedom from reoperation for structural valve deterioration (SVD; N=22) was 81% (95% CI 73-89) at 9 years and did not differ between SC and ARR (P=0.51). Independent predictors of degenerative SVD were younger patient age (HR 0.93 with age as continuous variable; 95% CI 0.90-0.97), older donor age (HR 1.06 with age as a continuous variable; 95% CI 1.00-1.11), larger allograft diameter (HR 1.38; 95% CI 1.11-1.71) and the use of pulmonary allografts (HR 10.72; 95% CI 3.88-29.63). Calculated median time to reoperation for structural valve deterioration ranged from 23 years in a 65-year-old patient to 12 years in a 25-year-old.

CONCLUSIONS

Aortic valve replacement with allografts yields adequate midterm results. Although important changes have been made over the years to improve durability, allografts still have a limited life span especially in young patients.