A North American, Prospective, Multicenter Assessment of the Mitroflow Aortic Pericardial Prosthesis

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.

Fifty years of the pericardial valve: Long-term results in the aortic position

It is now 50 years since the development of the first pericardial valve in 1971. In this time significant progress has been made in refining valve design aimed at improving the longevity of the prostheses. This article reviews the current literature regarding the longevity of pericardial heart valves in the aortic position. Side by side comparisons of freedom from structural valve degeneration are made for the valves most commonly used in clinical practice today, including stented, stentless, and sutureless valves. Strategies to reduce structural valve degeneration are also discussed including methods of tissue fixation and anti-calcification, ways to minimise mechanical stress on the valve, and the role of patient prosthesis mismatch.

Incidence and influence of prosthesis-patient mismatch after reoperative aortic valve replacement: a retrospective single-center study

Background

Reoperative aortic valve replacement (AVR) is associated with increased mortality compared with initial surgery, and a smaller valve might be implanted during repeat AVR (re-AVR; AVR after prior AVR). We describe the clinical outcomes and incidence of prosthesis-patient mismatches (PPM) after reoperative AVR.

Methods

Among 113 patients who underwent reoperative AVR between 2007 and 2018, 44 underwent re-AVR and 69 underwent a first replacement of a diseased natural valve after any cardiac surgery except AVR (primary AVR). We then compared early and late outcomes, the impact of re-AVR on the effective orifice areas (EOA), and the incidence and influence of PPM on reoperative AVR.

Results

Hospital mortality was 2.7%, and the overall 1-, 3-, and 5-year survival rates were 95, 91 and 86%, respectively. The reference EOA of the newly implanted valve was smaller than that of the previous valve (1.4 ± 0.3 vs. 1.6 ± 0.3 cm², p < 0.01). The mean pressure gradient was greater (15.2 ± 6.4 vs. 12.7 ± 6.2 mmHg, p = 0.04) and indexed EOA was smaller (0.92 ± 0.26 vs. 1.06 ± 0.36 cm²/m², p = 0.04) during re-AVR than primary AVR, whereas the incidence of PPM was similar (38.7% vs. 34.8%, p = 0.87) between the groups.

Conclusions

The clinical outcomes of reoperative AVR were acceptable. Although the reference EOA of new implanted valves was smaller than that of previous valves, re-AVR did not increase the incidence of PPM. These findings might serve as a guide for future decisions regarding the surgical approach to treating degenerated prosthetic valves.

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.

Magna Ease versus Trifecta Early Hemodynamics

Objective

This meta-analysis compares the early echocardiographic outcomes of aortic valve replacement using the two most commonly implanted stented bioprostheses.

Methods

We searched MEDLINE and EMBASE databases until 2017 for studies comparing Magna or Magna Ease (Edwards Lifesciences, Irvine, CA USA) versus Trifecta (St Jude Medical, St. Paul, MN USA) aortic bioprosthetic valves. A random-effects meta-analysis was performed for the primary outcome of mean gradient on echocardiography and secondary outcomes of effective orifice area, indexed effective orifice area, and in-hospital mortality.

Results

There were two randomized controlled trial, three matched, and six unmatched retrospective observational studies with 2119 patients [median reported follow-up = 6 months (interquartile range = 6 to 12)]. The Magna/Magna Ease valve was associated with higher early mean gradient (mean difference = 4.09, 95% confidence interval = 3.48 to 4.69, P < 0.0001) and smaller effective orifice area (mean difference = 0.30, 95% confidence interval = −0.38 to −0.22, P < 0.0001). There were no differences in 30-day mortality between Magna/Magna Ease and Trifecta (relative risk = 1.01, 95% confidence interval = 0.41 to 2.50, P = 1.0).

Conclusions

Trifecta may offer a small hemodynamic advantage compared with the Magna/Magna Ease valve with no differences in early mortality. Long-term follow-up is required to determine whether these differences persist and translate into differences in clinical outcomes.

One-year outcomes associated with a novel stented bovine pericardial aortic bioprosthesis

OBJECTIVES

The study objectives were to evaluate the safety, effectiveness, and hemodynamic performance of a new stented bovine pericardial aortic valve.

METHODS

This trial enrolled patients with symptomatic moderate or severe aortic stenosis or chronic, severe aortic regurgitation. We assessed death, valve-related adverse events, functional recovery, and hemodynamic performance at discharge, 3 to 6 months, and 1 year, as required by the US Food and Drug Administration for regulatory approval. The primary analysis compared late linearized rates of valve-related adverse events after implantation with Food and Drug Administration-specified objective performance criteria to determine whether the adverse event rates associated with the valve are within acceptable limits. Adverse events included thromboembolism, thrombosis, all and major hemorrhage, all and major paravalvular leak, and endocarditis.

RESULTS

The primary analysis included 864 patients who received an implant and 904.1 valve-years of follow-up. A total of 577 patients completed the 1-year evaluation. The primary end point was met for death, thromboembolism, thrombosis, all and major paravalvular leak, and endocarditis, but not for all and major hemorrhage. At 1 year, freedom from all death and from valve-related death was 96.4% and 99.7%, respectively. From baseline to 1 year, New York Heart Association class changed as follows: I, 10.8% to 73.7%; II, 48.9% to 22.6%; III, 38.0% to 3.5%; and IV, 2.3% to 0.2%. Effective orifice area increased from 0.9 ± 0.5 to 1.5 ± 0.4 (P < .0001), and mean aortic gradient decreased from 42.7 ± 16.5 to 12.5 ± 4.3 (P < .0001).

CONCLUSIONS

This analysis of a new stented bovine pericardial aortic valve demonstrated low overall mortality and valve-related adverse events, and hemodynamic performance comparable to that of other surgical aortic valves.

Clinical outcome and hemodynamic behavior of the Labcor Dokimos Plus aortic valve

Background

The Labcor Dokimos Plus (LDP) is a stented externally mounted pericardial aortic bioprosthesis, which was recently introduced in Europe. Aims of the study are evaluation of operative and postoperative results as well as hemodynamic performance.

Methods

One hundred consecutive patients with a mean age of 65.9 ± 10.7 years (range 35–87) and a mean EuroSCORE II of 3.1 ± 3.9 (range 0.67–24.5) underwent aortic valve replacement with the LDP. Mean valve-size was 25.2 ± 1.7 mm. Concomitant procedures were performed in 34% of the cases. Postoperative clinical data were analyzed and hemodynamic performance of the prostheses was evaluated by transthoracic echocardiography. Clinical follow-up was 100%, echocardiographic follow-up was 93% complete.

Results

Intraoperatively no peculiarities occurred. Mean cross clamp times for isolated and complex procedures were 74.5 ± 20.0 min and 103.7 ± 37.1 min, respectively. Patients were extubated after a mean of 9.4 ± 15.8 h. There were no perioperative strokes. Bleeding events occurred in 4 patients. 30-day-mortality was 2%. One case of early endocarditis occurred. Echocardiography showed maximum and mean pressure gradients of 18.1 ± 6.4 and 9.6 ± 3.7 mmHg, respectively. Correspondingly to valve sizes 21, 23, 25 and 27 mm, mean pressure gradients were 17.3, 9.5, 8.5 and 10.2 mmHg, effective orifice areas were 1.92, 1.79, 2.0, 2.16 cm² and indexed effective orifice areas were 1.08, 0.95, 0.99 and 1.01 cm²/m², respectively. No relevant regurgitations occurred.

Conclusions

The LDP showed operatively no peculiarities and a satisfactory clinical outcome with low perioperative morbidity and mortality. The hemodynamic performance of the implanted valve sizes was satisfactory.

St. Jude Medical Trifecta aortic valve: results from a prospective regional multicentre registry

Background

The Trifecta aortic bioprosthesis (St. Jude Medical, Inc., St. Paul, MN, USA) is a stented pericardial heart valve with excellent preliminary results. Aim of the study was to evaluate its early clinical and hemodynamic performances in a multicenter regional registry.

Methods

Between January 2011 and June 2012, 178 consecutive patients undergoing aortic valve replacement with the Trifecta bioprosthesis were prospectively enrolled at 9 Italian centers. Clinical and echocardiographic data were collectedat discharge, 6-months and at 1-year postoperatively.

Results

The average age was 75.4 ± 7.7 years,and 95 (53 %) were men. Indication for valve replacement included stenosis in 123 patients (69 %), mixed lesions in 25 (14 %), and regurgitation in 30 (17 %). Ninety-three (52 %) patients were in NYHA functional class III/ IV. Hospital mortality accounted for 5 (2.8 %) patients. No valve-related perioperative complications were encountered. Median follow-up was 20.5 months (range: 1-34). Early (≤6 months) complications included one thromboembolic event, one major bleeding, and 3 endocarditis (2 explants). Two late (>6 months) thromboembolic events and two endocarditis (1 explant) were registered. No valve thrombosis or structural deterioration were observed after discharge. At 30-months, freedom from all-cause mortality was 87 %, freedom from valve-related mortality 99.4 %, freedom from endocarditis 97.5 %, and freedom from valve explants 98 %. At 1-year, mean gradients ranged from 8 to 16 mmHg, and effective orifice area indexes from 1.0 to 1.2 cm²/m² for valve sizes from 19 to27 mm, respectively. No patients had severe prosthesis-patient mismatch.

Conclusions

Trifecta bioprosthesis provided favourable clinical and hemodynamic results over time.

Structural analysis of a stented pericardial heart valve with leaflets mounted externally

Our aim was to understand the structural and functional behaviour of a pericardial heart valve with biological leaflets attached externally to a stent. To our knowledge, there is little if any literature concerning these kinds of bioprosthetic heart valves, while there is more concerning bioprosthetic heart valves with leaflets mounted internally. We studied the problem using a finite element approach considering leaflets and stent interaction, the influence of leaflet anisotropy and stent stiffness, by comparing quasi-static and dynamic loadings. Although we considered the problem to be symmetric and fluid-structure interaction was not implemented, we believe that our results could be a solid basis for valve optimization. We found regions of high stress concentration at the commissure near the stent tip and at the base of the leaflet cusp. The structural behaviour in the first region was complex, while the stress in the second region acted radially because of high bending. Although leaflet tissue anisotropy and stent stiffness exerted a significant influence on the structural and functional behaviours, they had a contrasting effect on leaflet stress state, coaptation and valve opening. Therefore, a good optimization should take into account both structural and functional requirements when tuning tissue properties and stent stiffness.

The Bentall procedure with a biological valved conduit: substitute options and techniques

As originally described by Bentall and De Bono, aortic root replacement with reimplantation of the coronary arteries using a composite valved conduit represents the gold standard intervention in patients with aneurysmal disease or dissection involving the aortic root. Over the last decade, the number of Bentall procedures performed using biological valved conduit has dramatically expanded mainly due to the increased incidence of aortic disease in the aging population. Here, we sought to describe the commercially available biological composite grafts and the techniques that, to the best of our knowledge, are most frequently used in this setting.

New CoreValve Evolut 23 mm technology for treatment of degenerated bioprosthesis

The treatment of degenerated surgical bio-prosthetic heart valves (BHV) has been reported as a novel indication for TAVI. The intervention may be complicated by high residual transvalvular gradients and coronary ostia obstruction, especially in small size BHV. We report two cases of BHVs treated with the new CoreValve Evolut 23 mm highlighting the importance of fluoroscopic guidance, based on BHV markers, in achieving a correct TAVI implantation. The small dimensions of the new CoreValve Evolut 23 allowed us to obtain low residual gradients even in this particular subset of degenerated BHV.

The role of echocardiography during mitral valve percutaneous interventions

Transesophageal echocardiography is routinely used to guide percutaneous interventions involving the mitral valve. Mitral balloon valvuloplasty for rheumatic mitral valve stenosis (MS) was the first percutaneous intervention to gain wide acceptance. New techniques have been developed to treat degenerative and functional mitral regurgitation (MR) as well as paravalvular mitral leak (PVML). This review describes the use of echocardiography for transcatheter treatment of MS, MR, and PVML.