The Sorin Freedom Stentless Pericardial Valve: Clinical and Echocardiographic Performance at 10 years

In Vitro Study of a Stentless Aortic Bioprosthesis Made of Bacterial Cellulose

PURPOSE

The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium.

METHODS

Each model (named V1, V2 and V3) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg.

RESULTS

The V3 model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V1, V2 and V3 was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm2, respectively. The mean flow rate through the V3 valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V1, V2 and V3 was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg.

CONCLUSIONS

The V3 model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V3 model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.

Standardized Definition of Structural Valve Degeneration for Surgical and Transcatheter Bioprosthetic Aortic Valves

Bioprostheses are prone to structural valve degeneration, resulting in limited long-term durability. A significant challenge when comparing the durability of different types of bioprostheses is the lack of a standardized terminology for the definition of a degenerated valve. This issue becomes especially important when we try to compare the degeneration rate of surgically inserted and transcatheter bioprosthetic valves. This document, by the VIVID (Valve-in-Valve International Data), proposes practical and standardized definitions of valve degeneration and provides recommendations for the timing of clinical and imaging follow-up assessments accordingly. Its goal is to improve the quality of research and clinical care for patients with deteriorated bioprostheses by providing objective and strict criteria that can be utilized in future clinical trials. We hope that the adoption of these criteria by both the cardiological and surgical communities will lead to improved comparability and interpretation of durability analyses.

Prognosis after surgical replacement with a bioprosthetic aortic valve in patients with severe symptomatic aortic stenosis: systematic review of observational studies

OBJECTIVE

 To determine the frequency of survival, stroke, atrial fibrillation, structural valve deterioration, and length of hospital stay after surgical replacement of an aortic valve (SAVR) with a bioprosthetic valve in patients with severe symptomatic aortic stenosis.

DESIGN

 Systematic review and meta-analysis of observational studies.

DATA SOURCES

 Medline, Embase, PubMed (non-Medline records only), Cochrane Database of Systematic Reviews, and Cochrane CENTRAL from 2002 to June 2016.

STUDY SELECTION

 Eligible observational studies followed patients after SAVR with a bioprosthetic valve for at least two years.

METHODS

 Reviewers, independently and in duplicate, evaluated study eligibility, extracted data, and assessed risk of bias for patient important outcomes. We used the GRADE system to quantify absolute effects and quality of evidence. Published survival curves provided data for survival and freedom from structural valve deterioration, and random effect models provided the framework for estimates of pooled incidence rates of stroke, atrial fibrillation, and length of hospital stay.

RESULTS

 In patients undergoing SAVR with a bioprosthetic valve, median survival was 16 years in those aged 65 or less, 12 years in those aged 65 to 75, seven years in those aged 75 to 85, and six years in those aged more than 85. The incidence rate of stroke was 0.25 per 100 patient years (95% confidence interval 0.06 to 0.54) and atrial fibrillation 2.90 per 100 patient years (1.78 to 4.79). Post-SAVR, freedom from structural valve deterioration was 94.0% at 10 years, 81.7% at 15 years, and 52% at 20 years, and mean length of hospital stay was 12 days (95% confidence interval 9 to 15).

CONCLUSION

 Patients with severe symptomatic aortic stenosis undergoing SAVR with a bioprosthetic valve can expect only slightly lower survival than those without aortic stenosis, and a low incidence of stroke and, up to 10 years, of structural valve deterioration. The rate of deterioration increases rapidly after 10 years, and particularly after 15 years.

Surgical management of destructive aortic endocarditis: left ventricular outflow reconstruction with the Sorin Pericarbon Freedom stentless bioprosthesis†

OBJECTIVES

The treatment of complicated aortic endocarditis with periannular abscesses and root disarrangement is a surgical challenge, and includes left ventricular outflow tract (LVOT) reconstruction with the patch technique or homograft implantation. The results of a simplified technique to reconstruct the LVOT in destructive endocarditis of either the aortic native valve or valve prosthesis with the Sorin Pericarbon Freedom stentless valve are reported.

METHODS

Since August 2007, 40 patients with destructive endocarditis (mean age: 69 ± 12, 75% males, European System for Cardiac Operative Risk Evaluation II (EuroSCORE II): 19 ± 13, New York Heart Association (NYHA) class: ≥3 in all cases) have undergone LVOT reconstruction with a Sorin Pericarbon Freedom stentless bioprosthesis. Seven patients (17.5%) were in septic or cardiogenic shock preoperatively, and 18 patients (45%) suffered from moderate or severe aortic regurgitation. Eleven patients (27.5%) experienced preoperative systemic embolizations. Thirty-six cases (90%) were valve redos and 9 patients (22.5%) had concomitant procedures. The mean follow-up was 26 ± 25 months.

RESULTS

One patient (2.5%) died early (<30 days) and another 3 patients never discharged died due to multiorgan failure and septic shock. Actuarial survival rate was 85 ± 6% at 1 year, and 76 ± 8% at 3 and 5 years, respectively. Twelve patients (30%) required pacemaker implantation because of atrioventricular block and 20 patients (50%) developed or showed a progression of renal failure. One patient (2.5%) had an endocarditis relapse, and 1 (2.5%) showed a mild paraprosthetic aortic leak. No patient needed reoperation. At the last echocardiographic evaluation, mean gradient, peak gradient and left ventricular ejection fraction were 7.9 ± 5.0 mmHg, 15.1 ± 7.2 mmHg and 63.3 ± 9.3%, respectively.

CONCLUSIONS

The Sorin Pericarbon Freedom stentless prosthesis, with the modified technique herein described, seems to be a good option in most of cases of destructive aortic valve endocarditis. It is promptly available in different sizes, easy to implant and, due to its pericardial inflow skirt, ideal for extensive reconstruction of the LVOT with good haemodynamic performance and low risk of relapse.