Fate of trileaflet equine pericardial extracardiac conduit used for the correction of anomalies having pulmonic ventricle-pulmonary arterial discontinuity

Preliminary Results with a Novel expanded Polytetrafluoroethylene-based Pulmonary Valved Conduit

BACKGROUND

A novel polymeric pulmonary valved conduit, resistant to calcification and structural valve deterioration, may provide a more durable therapy option for the pediatric population by preventing loss of right ventricular function and increasing freedom from valve-related reintervention and mortality.

METHODS

This was a prospective, multicenter, single-arm study evaluating safety and performance of an investigational novel ePTFE-based valve. Patients met study inclusion/exclusion criteria, had a signed informed consent, had pre- and post-operative evaluation via transthoracic echocardiography and six-month cardiac magnetic resonance imaging (cMRI).

RESULTS

Seventeen patients were enrolled from 3 sites. Median age was 12 years (range, 6-17) with 52.9% male. BSA ranged from 0.82 to 1.57 m². There has been no mortality and 100% freedom from device related reinterventions. Baseline compared to six-month cMRI (in 11 of 16 patients with available data) suggests favorable right ventricular remodeling (RVEDV 123±37 to 94±25 mL/m²) with no significant change in ejection fraction. Through current follow-up, no patient has an RVOT gradient > 20 mmHg, (mean 11.2 ± 4.3 mmHg). No evidence of worsening valvular insufficiency was observed throughout postoperative serial TTE evaluations. No pulmonary regurgitation above baseline (≤ mild) was observed. No patient developed endocarditis. No thrombus or calcification was identified.

CONCLUSIONS

This preliminary evaluation of a novel ePTFE-based valved conduit suggests promising valve function with no thromboembolic or infectious complications, no valve related reinterventions, no valve-related adverse events or unexpected findings, improved right ventricular volumes, and encouraging hemodynamic performance through current follow-up.

In search of a pediatric cardiac surgeon’s ‘Holy Grail’: the ideal pulmonary conduit

The limited lifespan of all currently available conduits leads to repeat operations and interventional procedures in many children. Each reoperation entails considerable risk to life, expenditure and compromised quality of life as the conduit degenerates. The ideal conduit should be available freely, inexpensive, require no anticoagulation, be resistant to infection, free from thromboembolism, have no gradients or regurgitation and have unlimited durability. This review explores various options as surgeons and researchers endeavor to develop the ideal conduit--which will fulfill all of the above-mentioned criteria. Various currently available conduits are analyzed. Special emphasis is given to tissue-engineered valves and percutaneous valve implantations.

Right ventricular outflow tract reconstruction with a polytetrafluoroethylene monocusp valve: A twelve-year experience

OBJECTIVE

Transannular patching of the right ventricular outflow tract results in pulmonary insufficiency. Biologic monocusp valves prevent early pulmonary insufficiency but usually become nonfunctional in less than 1 year. Polytetrafluoroethylene monocusp leaflets demonstrated favorable characteristics in our animal studies and have been applied to a variety of right ventricular outflow tract reconstructions at our institution.

METHODS

From 1994 through 2006, 192 patients (mean age, 3.3 +/- 5.0 years) underwent right ventricular outflow tract reconstruction with a polytetrafluoroethylene monocusp valve (192 patients; 202 implants). Intraoperative, early postoperative, and late follow-up echocardiographic data (mean interval, 4.9 +/- 3.1 years; range, 6 months to 12 years) were retrospectively obtained to compare clinical outcomes among three preoperative diagnostic groups: patients undergoing initial repair of tetralogy of Fallot or pulmonary atresia/ventricular septal defect (group I), patients undergoing redo right ventricular outflow tract procedures (group II), and patients undergoing complex initial repairs (group III).

RESULTS

There were 4 early and 5 late deaths (9/192; 5%). The difference between the preoperative and postoperative peak right ventricular outflow tract gradients was significant (71.2 vs 23.1; P < .0001). Twenty-five (14%) patients had mild-to-moderate right ventricular outflow tract stenosis at one or more locations proximal and/or distal to the monocusp patch (mean gradient, 44.7 +/- 20.3 mm Hg). Freedom from increased pulmonary insufficiency greater than moderate was 86% at 1 year, 68% at 5 years, and 48% at 10 years. Twenty-five patients have undergone 35 reoperations 4.2 +/- 3.1 years (range, 3 months to 10 years after initial repair). Kaplan-Meier freedom from reoperation was 96%, 89%, and 82% at 1, 5, and 10 years. Freedom from reoperation in group II (69%) was significantly different from group I (88%; P = .01) and from group III (90%; P = .02), but there was no difference between groups I and III.

CONCLUSIONS

Use of a polytetrafluoroethylene monocusp valve prevents early and significantly reduces midterm pulmonary insufficiency. It is relatively inexpensive, easy to construct, and remains free from significant stenosis in the majority of patients. We have not witnessed significant calcification or pulmonary embolization, and the only antithrombic agent used has been low-dose aspirin.

Early clinical experience with a new tubular equine pericardial stentless aortic valve

BACKGROUND

This study details a single-center experience with the 3F Therapeutics stentless aortic bioprosthesis(investigational device) and is part of a prospective,nonrandomized worldwide multicenter study. We assessed the implantation procedure and the valve's efficacy in terms of early mortality and morbidity and early echocardiographic valve performance.

METHODS

Between June 2001 and March 2004, 24 patients (14 men/10 women) underwent aortic valve replacement(AVR) with a 3F valve. Mean age was 72 +/- 13 years(range, 31-88 years). Combined revascularization was performed in 12 patients; 1 patient received biatrial ablation therapy, 1 patient a myectomy, and 3 patients combined carotid endarterectomy. Echocardiographic systolic gradient and valve performance were investigated intra- and postoperatively by Doppler echocardiography.

RESULTS

There were 2 perioperative deaths, 1 non-valve related, due to aortic rupture in an 83-year-old woman, and 1 fatal cerebral embolism in a 77-year-old woman 5 days postoperatively. Cardiopulmonary bypass time was 102 +/- 32 minutes,aortic cross-clamp time was 79 +/- 24 minutes. Sizes for implanted 3F valves were 5 x 23 mm, 6 x 25 mm, 7 x 27 mm,and 6 x 29 mm. Follow-up systolic gradient results were 11.5 +/- 4.7 mm Hg at 30 days (n = 21), 11.4 +/- 4.5 mm Hg at 6 months (n = 18), and 13.3 +/- 4.4 mm Hg at 12 months (n =13). During the follow-up period trivial central aortic valve regurgitation was found in 6 patients.

CONCLUSION

The 3F aortic valve shows favorable preliminary hemodynamic results. Owing to the new valve design,implantation technique is simplified compared with other stentless valves. Anticoagulation treatment is mandatory for the first 3 months postoperatively. Long-term observation is necessary to assess life span and durability.

Valves in development for autogenous tissue valve replacement

Currently available valve and conduit artery substitutes have one or more significant disadvantages including limited durability, thrombogenicity, susceptibility to infection, and a lack of growth potential. Prior attempts to use autologous tissues in the construction of valve or arterial substitutes to overcome some of these limitations have not been successful. The use of tissue engineering techniques to construct valve and arterial substitutes from individual autologous cell lines and biodegradable polymer scaffolds are now under investigation in the laboratory, and the initial short term results in animals have been encouraging. These tissue engineering techniques offer the possibility of creating structures for replacement of valves and conduit arteries which are viable and have the capacity for self-repair and therefore greater durability. In addition, these structures should be non-thrombogenic and less susceptible to infection, and will have growth potential. Copyright 1999 by W.B. Saunders Company

Partial left ventriculectomy: overall and late results in 44 class IV patients with 4-year follow-up

BACKGROUND

This study reports long-term results of partial left ventriculectomy (PLV).

METHODS

Forty-four patients with dilated cardiomyopathy were operated on in a 4-year study. Echocardiograms, catheterization, and stress tests with oxygen consumption (VO2) were performed.

RESULTS

The survivors' preoperative ejection fractions of 22.1% +/- 4.9% improved to 30.9% +/- 9.4%, left ventricular (LV) end-diastolic diameter decreased from 79.4 +/- 9.3 mm to 61.9 +/- 8.2 mm, and maximum VO2 consumption improved from 8.8 +/- 3.9 mL/kg per minute to 15.8 +/- 6.1 mL/kg per minute at 22.6 months. These data also showed improvements in nonsurviving patients, according to the last evaluation before death. Seven of 12 survivors (58.3%) were in New York Heart Association (NYHA) I and II in December 1998. Twelve patients had elevated pulmonary vascular resistance (PVR) contraindicating heart transplant. In five patients the PVR returned to normal and one high-PVR patient was transplanted at the 16th postoperative month. Survival was 56.8%, 47.7%, 38.4%, and 35.9%, respectively, at 3, 6, 12, and 18 months, with a tendency to stabilize at 32.7% thereafter. Arrhythmias and heart failure were the main causes of death.

CONCLUSIONS

In spite of improvement of ventricular function and quality of life of the survivors, high mortality is a limiting factor. PLV can be indicated as a bridge to heart transplantation in high-PVR patients or if ventricular assist devices or donor hearts are not available.

Pathologic finding of restenosis in stent-implemented right ventricle-pulmonary artery extracardiac conduit

We describe an excised specimen of a stent-implanted valved equine pericardial extracardiac conduit in the right heart. It appears from careful pathologic examination that the stent acted as a nidus for thrombus formation followed by thick neo-intimal development over the stent, which caused restenosis. Restenosis occurred despite anticoagulation.