The fate of small-size pericardial heart valve prostheses in an older patient population

Externally mounted versus internally mounted leaflet aortic bovine pericardial bioprosthesis: meta-analysis

BACKGROUND

Recent studies reported higher-than-expected rates of early structural valve degeneration (SVD) and/or reoperation of externally mounted leaflet aortic bioprosthesis compared with others. This meta-analysis aims to compare the outcomes of bioprostheses with externally versus internally mounted leaflet design in patients who underwent surgical aortic valve replacement (SAVR).

METHODS

MEDLINE and EMBASE were searched through November 2021 to identify comparative studies investigating outcomes following SAVR with either externally or internally mounted leaflet aortic bioprosthesis. Outcomes of interest were reoperation for SVD or any cause and all-cause mortality.

RESULTS

Our analysis included 15 observational studies that enrolled a total of 23,539 patients who underwent SAVR using externally mounted (n = 9338; 39.7%) or internally mounted leaflet (n = 14,201; 60.3%) bioprostheses. Externally mounted valves consisted of the Trifecta (Abbott, St Paul, MN) (n = 6146) and the Mitroflow (LivaNova, London, UK) (n = 3192), and all internally mounted valves were the Perimount (Edwards Lifesciences, Irvine, CA). Externally mounted valves compared with the Perimount were associated with higher reoperation rates for SVD [hazard ratio (HR) 3.55, 95% confidence interval (CI) 2.67-4.72; P < 0.001] and any cause (HR 9.36, 95% CI 3.70-23.67; P < 0.001). Furthermore, externally mounted valves demonstrated higher all-cause mortalities (HR 1.33, 95% CI 1.13-1.56; P < 0.001).

CONCLUSIONS

The present study summarizing updated evidence revealed higher reoperation rates and all-cause mortalities in patients with externally mounted leaflet aortic bioprostheses compared with those with internally mounted design. Choosing the right SAVR valve type is critical part of lifetime management of aortic valve disease.

Prosthetic cardiac valves: history and review of cardiac prostheses clinically available in Japan

Recently developed prosthetic valves are reliable and essential for the treatment of valvular heart disease. The mechanical valve evolved remarkably following the introduction of pyrolite carbon material, which enabled the creation of a bileaflet form incorporated with a pivot mechanism. The improved durability of the biological valve is attributed mainly to the development of a tissue fixation process and anti-calcification treatments. However, optimal antithrombogenicity and durability have not yet been achieved for either prosthetic valve type. To select the most suitable prosthetic valve for each individual patient from among the many clinically available prosthetic valves, it is necessary to have a thorough understanding of the characteristics of each valve.

The pathology of early failure in Mitroflow pericardial valve bioprosthesis (12A/LX)

BACKGROUND

Limited mid-term durability of 12A/LX Mitroflow bioprosthesis has been reported. Aim of the study was to ascertain the pathologic substrates and possible mechanisms of structural valve deterioration in explants from animals and humans.

METHODS

Nine aortic 12A/LX Mitroflow bioprostheses preserved in hypotonic solution and three aortic 12A/LX bioprostheses, preserved in isotonic solution, were explanted from juvenile sheep, mean time from implant 95.66 ± 36.04 days and 132.33 ± 28.88 days from implant respectively. One stented unimplanted 12A/LX Mitroflow preserved in isotonic colution before glutaraldeyde fixation served as control. Ten aortic 12A/LX Mitroflow bioprostheses were explanted from humans because of severe dysfunction: five children, (3 females and 2 males, mean age 14.19 ± 4.77 years, range 11-21), 26 ± 8.24 months from implant and 5 adults (4 females and 1 male, mean age 57.4 ± 19.85 years, range 31-72), 64.4 ± 26.94 months from implant. X-ray, histology, and transmission electron microscopy were carried out as well as spectroscopy for calcium (Ca++) and phosphorus (P) content in human explants.

RESULTS

Explants, from both animals and humans, showed cusp folding and stiffness, with coarse calcific deposits at gross examination and X-ray. Severe collagen denaturation, plasma insudation and massive calcification, involving both collagen and cell debris, were observed microscopically. Mean Ca++ content of 183.27 ± 62.48 and P content of 94.35 ±33.76 mg/g dry weight was found in children and Ca++ content of 205.49 ± 2.23 and P content of 99.75 ± 0.11 mg/g dry weight in adults. Obstructive fibrous tissue overgrowth was detected in 6 human cases.

CONCLUSIONS

Collagen denaturation was observed in pericardial Mitroflow 12A/LX bioprosthesis with premature structural valve deterioration. Optimal collagen fixation and preservation as well as phospholipids reduction by removing cell debris, as employed in the novel CROWN PRT Mitroflow bioprosthesis, are expected to solve the flaw and achieve long-term durability.

Aortic Valve Replacement in Elderly Patients With Small Aortic Annulus: Results With Three Different Bioprostheses

Objectives

Aortic valve replacement (AVR) in patients with small aortic annulus (diameter ≤21 mm) is considered a challenging scenario because of technical aspects and the high risk of patient-prosthesis mismatch (PPM). The choice of the appropriate prosthesis is crucial, and at the moment, an ideal device has yet to be identified. We compare clinical and hemodynamic results after AVR with three bioprostheses with different design and characteristics.

Methods

We retrospectively evaluated 76 consecutive patients from two cardiac surgery centers who underwent AVR (Trifecta = 24; Edwards INTUITY Elite valve system = 26, and Perceval = 26) for severe aortic stenosis between 2013 and 2017. Patients selected were older than 75 years and with an annulus diameter ≤21 mm at preoperative echocardiogram. Reinterventions and combined procedures were excluded. Minimally invasive AVR was performed in 44 (57.8%) patients. Telephonic interview was obtained at 2.9 ± 0.5 years and echocardiographic follow-up at 2.2 ± 0.8 years.

Results

Clinical outcome was similar in the three groups. At follow-up, Trifecta patients presented significantly higher peak and mean transprosthetic pressure gradients ( P = 0.04 and 0.01). Effective orifice area and left ventricular mass regression were comparable, although an advantage was observed in Perceval patients without reaching the statistical significance. Incidence of moderate ( P = 0.2) and severe PPM ( P = 0.7) was comparable.

Conclusions

Despite higher postoperative pressure gradients observed with the Trifecta valve, all three prostheses (Trifecta, Edwards INTUITY Elite, and Perceval) have proven to be reliable when implanted in small aortic annuli, with good clinical outcome and favorable left ventricular mass regression.

Structural valve deterioration in the Mitroflow biological heart valve prosthesis

OBJECTIVES

Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive in Denmark who had received a Mitroflow aortic bioprosthesis since 2000.

METHODS

Patients alive in Denmark with a Mitroflow bioprosthesis implanted since January 2000 were invited to participate in a nationwide cross-sectional study with a predefined definition of SVD. Of 1552 patients, 861 patients had died and 47 patients had been reoperated with 40 reoperations due to SVD. The remaining 644 patients were invited for evaluation; 574 patients accepted and were evaluated for SVD. The incidence of SVD was calculated using competing risk regression analysis with death as the competing event.

RESULTS

A total of 173 patients were diagnosed with SVD by echocardiography. Of these, 64 (11%) patients had severe SVD and 109 (19%) patients moderate SVD. Severe SVD was associated with the age of the prosthesis and small prosthesis size [Size 21: hazard ratio (95% confidence interval, CI) 2.72 (0.97-8.56), P = 0.06; Size 19: 6.26 (1.63-24.06), P = 0.008]. The cumulative incidences of reoperation or severe SVD at Year 9 were 12.5% for Size 19, 7.6% for Size 21 and 3.1 (1.2-6.4)% for Size 23. Median survival in patients with prosthesis Sizes 23-29 was 6.4 (95% CI 5.7-7.0) years, with Size 21 it was 6.5 (95% CI 5.9-7.1) years and with Size 19 it was 6.9 (95% CI 5.7-8.2) years (P = 0.78).

CONCLUSIONS

The incidence of undetected severe SVD was as high as the incidence of operated SVD. The overall risk for SVD is high for the Mitroflow bioprosthesis, especially if the prosthesis is small and older than 5 years.

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.