Long term outcome of mechanical valve prosthesis in the pulmonary position

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Abstract

Objectives

Assessment of the long term outcome of mechanical valve prosthesis at pulmonary position in a population of grown-up congenital heart disease patients from a tertiary referral center.

Methods

From 1977 to 2007, 22 consecutive patients underwent a total of 25 pulmonary valve replacements with mechanical prosthesis. The most frequent underlying cardiac condition was tetralogy of Fallot (n = 16, 64%) and the mean age at the time of pulmonary valve replacement was 32 ± 11 years (range 14–50 years).

Results

The postoperative mortality rate was 4% (n = 1) with no late deaths documented after a mean follow-up of 7.6 ± 7.6 years (range 0.29–24 years). No major bleeding episodes occurred. Three patients presented with valve thrombosis in the setting of long term anticoagulation withdrawal and required valve re-replacement. Two of these patients, both with poor right ventricular function and overt clinical signs of right heart failure at the time of valve re-replacement, experienced further episodes of thrombosis despite correct anticoagulation. All episodes resolved with thrombolysis. After addition of antiplatelet treatment in one case and anticoagulation self-control, in the other, no further thrombosis has been documented.

Conclusions

Mechanical valve prosthesis may be an alternative to tissue valve prosthesis in patients with congenital heart disease requiring pulmonary valve replacement. Optimal anticoagulation is crucial and additional antiplatelet treatment should be considered. Our data also suggest that patients with severe right ventricular dysfunction and congestive heart failure might be at particular risk for valve thrombosis.

Introduction

Pulmonary valve replacement is becoming increasingly common due to the development of long term complications in the growing population of adults with repaired congenital heart defects, particularly those diagnosed with tetralogy of Fallot. Long lasting severe pulmonary regurgitation with progressive right ventricular dilatation is the main indication for pulmonary valve replacement (PVR) in this cohort of patients.

When it comes to prosthesis selection, tissue valves are usually the preferred option [1] but their limited longevity [2], [3] makes reoperation almost unavoidable. Given the young age of these patients at the time of valve replacement, they may require repeated interventions during their lifespan, with an expected increasing surgical complexity.

Mechanical prostheses at pulmonary position have a less favorable reputation due to the increased risk of thrombosis reported in some limited old series [4], [5], [6]. However, more recent reports with appropriate anticoagulation management have failed to show such high risk of thrombosis,[7], [8], [9] proposing mechanical valve prosthesis as an alternative in patients with multiple reoperations given its potential longer durability.

The aim of our study was to evaluate the long term results of mechanical prostheses at pulmonary position implanted in our centre, with especial attention to hemorrhagic and thrombotic complications.

Section snippets

Patients and methods

After approval by the institutional research ethics board, 31 PVR procedures between February 1977 and October 2007 were identified using a prospectively maintained cardiovascular surgery database at the Hospital de la Santa Creu i Sant Pau. Of those, 6 procedures were tissue valve implants and 25 were mechanical valve prostheses, three of which were a second replacement. Therefore, our study sample consisted of 22 patients undergoing 25 pulmonary mechanical valve implantations. The selection

Results

There is complete follow up for all the patients except for a repaired tetralogy of Fallot male with severe pulmonary regurgitation and preoperative signs of overt heart failure who underwent PVR at 16 years of age. He continued follow up in another institution and no information about his current status could be retrieved. Two of the patients (patients 1 and 22) were initially lost to follow up. They returned to our outpatient clinic several years later (further details about these cases are

Discussion

In the last years an important change in the epidemiology of congenital heart diseases has occurred [11]. The good operative results achieved in the past decades and the improvement of survival in children with congenital heart disease repaired during childhood, are the main determinants for the increasing number of adults with residual lesions which may require reoperation during follow up. A major part of the reoperations in this population will consist of pulmonary valve implantation or

Limitations

Only the most recent patients in our series had preoperative cardiac magnetic resonance for assessment of right ventricular volumes and ejection fraction, which is currently considered the gold standard technique for assessment of right ventricular function. The majority of the patients had only qualitative estimate of right ventricular function on preoperative echocardiography and, in the oldest cases, description of the right ventricular performance was even lacking in the report.

Conclusions

According to our experience, mechanical prosthesis in the pulmonary position may be contemplated as an alternative to tissue valve prosthesis. Proper anticoagulation management is essential for good long-term results and addition of antiplatelet treatment should be considered. Patients with severe right ventricular dysfunction and congestive heart failure are suboptimal candidates, given the high risk of valve thrombosis in this cohort.

Acknowledgements

The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [18].

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