An Unexpected Risk Factor for Early Structural Deterioration of Biological Aortic Valve Prostheses

Excess Reintervention With Mitroflow Prosthesis for Aortic Valve Replacement: Ten-Year Outcomes of a Randomized Trial

BACKGROUND

Current bioprostheses are considered to have improved durability and better hemodynamic performance compared with previous designs, but there are limited comparative data on late outcomes.

METHODS

From 2009 through 2011, 300 adults with severe aortic valve stenosis undergoing aortic valve replacement (AVR) were randomly assigned to receive Edwards Magna, St Jude Epic, or Sorin Mitroflow bioprostheses (n = 100, n = 101, n = 99, respectively). Overall survival was analyzed using Kaplan-Meier and Cox proportional hazards methods, whereas competing risk analysis was used for all time-to-event outcomes. Serial echocardiographic data were fitted with longitudinal models stratified by implant valve size.

RESULTS

During median follow-up of 9.8 years (interquartile range, 8.7-10.2), 10-year survival was 50% for the Magna group, 42% for the Epic group, and 41% for the Mitroflow group (P = .415). Cumulative risk of stroke was 9% at 10 years, and rates were comparable for the three groups. Indexed aortic valve area and mean gradients were similar among the three groups receiving 19 mm and 21 mm valves, but in larger (23 mm or more) prostheses, gradients were lower (P < .001) and indexed aortic valve areas were higher in the Magna group (P < .001). The 10-year risk of endocarditis differed by group (P = .033), with higher incidence in the Mitroflow vs the Magna group (7% vs 0%, P = .019). Late risk of reinterventions in the Mitroflow group was 22%, compared with 0% in the Magna group (P < .001) and 5% in the Epic group (P = .008).

CONCLUSIONS

The Magna valve had the lowest gradients and largest indexed aortic valve area with larger implant sizes. The Mitroflow bioprosthesis is associated with an increased rate of reintervention and possible increased risk of infection compared with Magna and Epic valves.

Comparison of Long-term Performance of Bioprosthetic Aortic Valves in Sweden From 2003 to 2018

IMPORTANCE

The performance of bioprosthetic aortic valves is usually assessed in single valve models or head-to-head comparisons. National databases or registries offer the opportunity to investigate all available valve models in the population and allows for a comparative assessment of their performance.

OBJECTIVE

To analyze the long-term rates of reintervention, all-cause mortality, and heart failure hospitalization associated with commonly used bioprosthetic aortic valves and to identify valve model groups with deviation in clinical performance.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, nationwide cohort study included all adult patients who underwent surgical aortic valve replacement (with or without concomitant coronary artery bypass surgery or ascending aortic surgery) in Sweden between January 1, 2003, and December 31, 2018. Patients were identified from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry. Patients with concomitant valve surgery, previous cardiac surgery, and previous transcatheter valve replacement were excluded. Follow-up was complete for all participants. Data were analyzed from March 9, 2020, to October 12, 2021.

EXPOSURES

Primary surgical aortic valve replacement with the Perimount, Mosaic/Hancock, Biocor/Epic, Mitroflow/Crown, Soprano, and Trifecta valve models.

MAIN OUTCOMES AND MEASURES

The primary outcome was cumulative incidence of reintervention, defined as a subsequent aortic valve operation or transcatheter valve replacement. Secondary outcomes were all-cause mortality and heart failure hospitalization. Regression standardization and flexible parametric survival models were used to account for intergroup differences. Mean follow-up time was 7.1 years, and maximum follow-up time was 16.0 years.

RESULTS

A total of 16 983 patients (mean [SD] age, 72.6 [8.5] years; 10 685 men [62.9%]) were included in the analysis. The Perimount valve model group had the lowest and the Mitroflow/Crown valve model group had the highest cumulative incidence of reintervention. The estimated cumulative incidence of reintervention at 10 years was 3.6% (95% CI, 3.1%-4.2%) in the Perimount valve model group and 12.2% (95% CI, 9.8%-15.1%) in the Mitroflow/Crown valve model group. The estimated incidence of reintervention at 10 years was 9.3% (95% CI, 7.3%-11.3%) in the Soprano valve model group.

CONCLUSIONS AND RELEVANCE

Results of this study showed that the Perimount valve was the most commonly used and had the lowest incidence of reintervention, all-cause mortality, and heart failure hospitalization, whereas the Mitroflow/Crown valve had the highest rates. These findings highlight the need for clinical vigilance in patients who receive either a Soprano or Mitroflow/Crown aortic bioprosthesis.

Mitroflow Aortic Bioprosthesis Failure in Type B Aortic Dissection: Preventive Left Main Stenting in Transapical Transcatheter Aortic Valve Implantation Strategy

Mitroflow aortic prosthesis dysfunction in case of complex vascular disease is considered a challenging scenario. Because of the high risk for surgical reoperation and the presence of chronic aortic dissection originated from a calcified Kommerel diverticulum, we considered to perform a transapical valve-in-valve transcatheter aortic valve implantation (TAVI) procedure. Myocardial ischemia is a dreadful complication reported in valve-in-valve TAVI procedures, mainly in patients with degenerated Mitroflow aortic bioprostheses. Because of the narrow shape of Valsalva sinuses and the short distance between Mitroflow annulus and left coronary ostium, to overcome the risk of possible Mitroflow leaflets displacement during TAVI expansion thus overlapping coronary ostia, we performed a preventive angioplasty. Then, we implanted a bare metal stent on the left main protruding in the aortic root. At 3 years follow-up the patient was in good clinical conditions.

Early structural degeneration of Mitroflow aortic valve: another issue in addition to the mismatch?

We reported two cases of early structural valve degeneration (SVD) with Mitroflow prosthesis in aortic position in patients above the age of 65 years. Microscopic aspects have been analysed to investigate the intrinsic mechanism of SVD. New techniques to improve the structure and the preservation of this prosthesis are needed in order to reduce potential dangerous early complications.