Echocardiographic and pathologic features of explanted Hancock and Carpentier-Edwards bioprosthetic valves in the mitral position

Investigation of failure modes of explanted porcine valves in the mitral position

Background

Porcine valves are used for mitral valve replacement, but the limited long-term durability has restricted the application in younger patients. Degenerated porcine mitral valves were explanted to analyze the failure modes and damage characteristics.

Methods

Twelve porcine valves were explanted via secondary mitral valve replacement surgery. Microcomputed tomography scanning, morphological and pathological examinations were performed to classify the cusp tears, calcification, and pannus formation. The causes of valve deterioration were subsequently analyzed.

Results

The mean age at first implantation was 45.42±19.58 years (range, 11–64 years). The mean duration of implantation was 9.39±4.14 years (range, 4.25–18.75 years). The indications for first surgery were rheumatic heart disease in 8 patients (66.67%), infective endocarditis in 2 patients (16.67%), degenerative valvular disease in one patient (8.33%), and congenital heart disease in one patient (8.33%). Type I cusp tears and commissural dehiscence that occurred near the stent post position were found in 6 (50%) and 5 (41.67%) valves, respectively. Calcification was detected in 6 (50%) cases, and pannus was found in most valves (91.67%).

Conclusions

Leaflet damage occurred near the stent posts area was the main failure mode of porcine mitral valves in this study. Patients who undergo the first surgery at younger age, the higher prevalence rate of rheumatic heart disease, the structure of bioprosthetic porcine valve, and left ventricular stresses could be considered as the main factors causing valve deterioration.

Durability of Mitral Valve Bioprostheses: A Meta-Analysis of Long-Term Follow-up Studies

BACKGROUND

Porcine and pericardial valves exhibited similar freedom from structural valve deterioration after aortic valve replacement. Limited data exist regarding their durability at long-term follow-up in the mitral position.

METHODS

A literature search was performed through online databases. Papers reporting freedom from tissue valve deterioration after mitral valve replacement with a follow-up longer than 5 years were retrieved. Four porcine valves (Carpentier-Edwards [Edwards Lifesciences, Irvine, CA] and Hancock, Hancock II, and Mosaic [Medtronic, Inc, Minneapolis, MN]) and 1 pericardial prosthesis (Carpentier-Edwards) were the objects of the study. The structural valve deterioration (SVD) rate per year was calculated for each type of prosthesis. Kaplan-Meier curves and log-rank test analysis were performed to compare the long-term durability of porcine and pericardial valves.

RESULTS

Forty full-text papers including more than 15,000 patients were considered for the meta-analysis. Porcine valves were generally implanted in younger patients in the first period after their introduction. The mean age of the patients receiving a mitral bioprosthesis increased from 50 to 70 years over the decades. In patients operated after 1980 who had similar mean age at the time of implant, freedom from SVD was higher in the group of porcine valves with Mosaic prosthesis, showing the lowest rate of SVD. Long-term survival was higher for Mosaic porcine and Carpentier pericardial valves.

CONCLUSIONS

In surgical populations that underwent mitral valve replacement after 1980 with new generation tissue valves and similar mean age at the implant time, we found, at long-term follow-up, a higher freedom from SVD in the group of porcine prostheses.

Successful treatment of failing biological prosthesis because of "Stent creep" with valve-in-valve transcatheter aortic valve implantation

INTRODUCTION

Stent creep is an uncommon mode of structural deterioration of bioprosthetic heart valves defined by a permanent inward deflection of the stent posts. This may occur because of valve over-sizing and leads to intrinsic valve stenosis. It has been described in older generation of bioprosthesis and was thought not to occur in modern devices.

METHODS

We describe three patients who were referred for bioprosthetic valve degeneration with presumed aortic stenosis. Investigations demonstrated mid valvular gradient predominantly because of stent creep. We performed valve-in-valve TAVI with Edward SAPIEN prosthesis.

RESULTS

Median age was 84 and logistic EuroSCORE 34.4. All patients had degenerated bioprosthesis with mean implant duration of 5.6 years. Two patients had Carpentier Edwards Perimount prosthesis (19 and 23 mm) and one patient had a Mitroflow (21 mm). Mean gradients were 33, 54, and 22 mm Hg. About 23 mm Edward SAPIEN valve was implanted in all cases with immediate improvement in haemodynamics with mean gradient reduction to 10, 17, and 8 mm Hg, respectively. The mean aortic valve area increased from 0.63 to 1.76cm(2) . There were no serious adverse events. The patients improved from NYHA III/IV to I/II post procedure and remain well at median follow-up of 24-months.

DISCUSSION

Stent creep is an uncommon mode of structural deterioration in bioprosthetic heart valves. It has been described in the previous generation of bioprosthesis. It is important to distinguish leaflet dysfunction and stent creep. By forcing the stent posts outwards a balloon expandable TAVI device can be used to treat this condition.

A 10-year comparison of explanted Hancock-II and Carpentier–Edwards supraannular bioprostheses

BACKGROUND

Bioprosthetic heart valves are more frequently being used in valve replacement procedures today. Although second-generation bioprosthetic valves have improved functionality over their first-generation counterparts, they still often fail due to primary tissue degeneration.

METHODS

This study examines two second-generation porcine valves after surgical explantation, the Hancock-II (HAN; Medtronic Heart Valve Division, Irvine, CA, USA) and the Carpentier-Edwards supraannular (CE-SAV; Baxter Healthcare Corporation, now Edwards LifeSciences, Irvine, CA, USA), with special attention to morphological/histological changes and reasons for valve failure. A total of 98 HAN and 65 CE-SAV valves were explanted and seen over a 10-year period.

RESULTS

CE-SAV valves had a longer average implant duration than HAN valves (13.9+/-3.9 years vs. 10.0+/-5.1 years). Compared with HAN valves, CE-SAV valves also had a higher incidence of stent deformation (41.5% vs. 14.3%), calcification (75.4% vs. 54.1%), and pannus (100% vs. 91.8%).

CONCLUSIONS

The greater degenerative changes seen with CE-SAV valves over HAN valves may be due to the longer implant duration of CE-SAV valves in this series. To our knowledge, the present study is the first direct morphological comparison of these two valve models.

Commissural dehiscence: A rare and peculiar cause of porcine valve structural deterioration

OBJECTIVE

Calcification is the main cause of structural valve deterioration; however, other causes of failure have been identified, and among them, dehiscence of a commissure from the stent has been reported in several models of porcine valves. The aim of this study was to analyze the rate and mode of occurrence of this complication in first- and second-generation porcine bioprosthetic explants.

METHODS

Among 586 porcine xenografts explanted and analyzed at the Institute of Pathological Anatomy of the University of Padua, 17 (2.9%) have been replaced for incompetence because of commissural dehiscence. All these explants were in the mitral position, with the exception of a Carpentier-Edwards supra-annular aortic valve prosthesis.

RESULTS

Dehiscence was observed in 9 (1.9%) of 455 Hancock standard explants, in 1 (3.2%) of 31 Hancock II, in 3 (8.6%, 2 standard and 1 supra-annular) of 35 Carpentier-Edwards, in 1 (2.4%) of 42 Bioimplants, and in 3 (50%) of 6 Xenotech after a mean time function of 157 +/- 50, 156, 96 +/- 29, 143, and 130 +/- 8 months, respectively. Dehiscence was the sole cause of incompetence in 6 cases. An impending commissural dehiscence caused by blood creeping was observed in one case. This might be an explanation for the dehiscence other than excessive trimming of the aortic wall.

CONCLUSIONS

Commissural dehiscence is an uncommon and peculiar mode of failure of porcine valves implanted in the mitral position and was observed earlier and more frequently with Carpentier-Edwards porcine explants (P < .05). We speculate that pericardial strip protection of the suture between the Dacron fabric and porcine aortic wall, as used in the Biocor porcine valve, might prevent this complication.

Survey of observer variation in transesophageal echocardiography: comparison of anesthesiology and cardiology literature

OBJECTIVE

Transesophageal echocardiographic examination tends to be somewhat observer and experience dependent, and observer bias can arise easily when data are calculated and interpreted by unskilled, nonblinded, or single observers. The study plan was to see whether authors have adequately described how observer bias is minimized in their studies. Thus, a study was conducted systematically reviewing methods reported in transesophageal echocardio graphy articles in peer-reviewed anesthesiology journals versus those reported in peer-reviewed cardiology journals.

INTERVENTIONS

After MEDLINE searches of the literature published from 1997 through 1999, the authors investigated 56 anesthesiology reports and 56 randomly selected, year-matched cardiology reports. An 8-item questionnaire was developed that examined several factors: the number of observers and their experience levels, whether observers were blind to clinical data, whether low-quality images were excluded, the use of on-line or off-line analysis, and observer variability.

MAIN RESULTS

The analysis revealed inadequacies in reporting of important information that relates to bias and quality in 91.1% of anesthesiology and 98.2% of cardiology articles. Observer variability was not reported in 50.0% of the anesthesiology reports and 67.9% of the cardiology reports; however, difference between the 2 bodies of literature was not significant. The journal impact factor was significantly higher for the cardiology literature than for the anesthesiology literature (2.42 [0.386-10.893] v 1.07 [0.664-3.439]; median [range], p < 0.001).

CONCLUSION

Articles reviewed had at least some inadequacies in reporting the methods to minimize observer bias in both the anesthesiology and cardiology literature. Reporting methodology standards in TEE examinations remain to be established.

Commissural dehiscence and pannus formation of porcine heart valve bioprostheses

From May 1976 to June 2001, 95 porcine heart valve bioprostheses (BPs) were explanted. Among them, 85 prostheses were available for an analysis of structural valve deterioration (SVD). There were 32 Hancock (H) BPs and 53 Carpentier-Edwards (CE) BPs, with a mean implantation duration of 12 +/- 3.5 and 11.0 +/- 4 years, respectively. There were two extraordinary complications. One was commissural dehiscence (CD) of the CEBPs in 10/53 cases (18.9%), with a mean duration of 12.7 +/- 2.7 years. This was not observed in the HBPs. The other was pannus formation in both BPs. In the mitral position, it was 25/32 (78.1%) in HBPs and 37/53 (69.8%) in CEBPs. In the aortic position, it was 4/32 (1.3%) in the HBPs and 11/53 (20.8%) in the CEBPs. We conclude that CD could not be diagnosed preoperatively and anticoagulation is therefore indicated to prevent pannus formation of such prostheses, particularly in those located in the mitral position.

Long-term evaluation of Carpentier-Edwards porcine bioprosthesis for rheumatic heart disease

OBJECTIVES

The clinical results of Carpentier-Edwards standard bioprosthesis have been extensively studied for valvular heart surgery in America and Europe. However, the data of long-term performance of Carpentier-Edwards standard porcine valve in areas with a high prevalence of rheumatic heart disease are still lacking. In this study, we assessed the clinical performance of Carpentier-Edwards standard porcine bioprostheses in a patient group with high prevalence of rheumatic heart disease.

METHODS

A total of 872 patients underwent valvular heart surgery with Carpentier-Edwards standard porcine bioprostheses replacement between 1975 and 1999 and the results were analyzed. Rheumatic etiology counts for 95% of the patients. Mean age of operation was 40 +/- 14 years (mitral valve), 43 +/- 19 years (aortic valve), and 45 +/- 13 years (double valve). Follow-up was 95.6% complete and continued up to 24 years (total 7017 patient-years) with mean of 8.9 +/- 5.1 years.

RESULTS

The operative mortality rate was 5.85%. Actuarial patient survival rates after discharge at 5, 10, 15, and 20 years were 92.5%, 83.8%, 72.3%, and 35.8%, respectively. A total of 442 cases received reoperation due to failure of bioprostheses. The mean duration to valve failure is 12.2 +/- 0.4 years. Actuarial estimate of freedom from structural valvular failure at 5, 10, 15, and 20 years were 96.3%, 63.7%, 24.4%, and 7.7%, respectively.

CONCLUSION

The long-term result of Carpentier-Edwards standard bioprostheses in the present patient group is satisfactory. However, freedom from valve failure is lower than that of Western series. Younger age at operation and higher prevalence of rheumatic etiology in this area are possible causes.