Mechanical Valve Replacement in Congenital Heart Defects in the Era of International Normalized Ratio Self-Management

A case report of right ventricular outflow tract obstruction caused by B-cell lymphoma: a rare presentation in an adult patient with pulmonary atresia

Background

Right ventricle outflow tract (RVOT) dysfunction is a common long-term complication in adult patients with pulmonary atresia/ventricular septal defect (PA/VSD). Common causes include valve thrombosis, stent fractures, and graft calcification. We present, to the best of our knowledge, the first case of malignant invasion of a Gore-Tex conduit, causing severe right ventricle (RV) failure.

Case summary

A 30-year-old woman with a history of PA/VSD with major aortopulmonary collateral arteries (MAPCAs) presented with worsening dyspnoea and exercise intolerance. In infancy, she underwent unifocalization of the right- and left-sided AP collaterals utilizing an 18 and 16 mm Gore-Tex graft, respectively. At age 7, she had surgical repair with VSD patch closure and placement of a 20 mm right ventricle-pulmonary artery (RVPA) homograft connected to a 20 mm Gore-Tex graft with linkage to the previously placed right and left unifocalization grafts. A transthoracic echocardiogram revealed a severely dilated RV and a heavily calcified RVOT conduit with severe stenosis. Cardiac computed tomography showed a stenotic RVPA conduit with calcified mural mass. She underwent surgical revision of the RVPA conduit with thromboendarterectomy of bilateral pulmonary arteries. Pathology of the removed conduit revealed fibrin-associated Epstein–Barr virus-positive diffuse large B-cell lymphoma (FA DLBCL).

Discussion

One prior case report has demonstrated invasion of DLBCL involving an aortic synthetic tube graft. However, malignant invasion of the RVOT Gore-Tex conduit has yet to be reported. Pathological review can be essential in guiding management. Malignant invasion of Gore-Tex conduits is a rare phenomenon, but one that should be closely monitored following repair of the RVOT.

Mid-term outcomes of mechanical pulmonary valve replacement: a single-institutional experience of 396 patients

OBJECTIVES

Previous small-sized studies have demonstrated the safety and efficacy of mechanical pulmonary valve replacement (mPVR) in patients with congenital heart disease; however, the predictors of major complications and reoperation remained unclear.

METHODS

In a retrospective study, we reported the mid-term outcomes of a large-scaled series of patients, 396 patients, with congenital heart diseases who underwent mPVR in a single institution.

RESULTS

The patients' mean age at mPVR was 24.3 ± 9 years (4-58 years). Most patients (84.3%) underwent tetralogy of Fallot total correction. The median of follow-up was 36 months (24-49 months). Prosthetic valve malfunction caused by thrombosis or pannus formation developed in 12.1% of patients during follow-up period. Reoperation was performed in 7 cases with pannus formation and 6 cases with mechanical valve thrombosis. Freedom from reoperation at 1, 5, and 10 years was 99%, 97%, and 96%, respectively. Neither early nor mid-term mortalities were detected. Cox regression models showed that male gender and smaller valve size increased the risk of prosthetic valve failure. The age at mPVR, interval between congenital heart defect repair and mPVR, and concomitant procedures predicted reoperation. In multivariate analysis, younger age and the interval between first operation and mPVR predicted reoperation either.

CONCLUSIONS

The success rate of mPVR is excellent in mid-term follow-up. Younger age, longer interval between the repair of congenital defect and mPVR, and cooperation increased reoperation risk. However, strict adherence to life-long anticoagulation regimen and patient selection are of great importance for the implementation of mPVR.

Self-testing and self-management of oral anticoagulation therapy in children

Children and adolescents on oral anticoagulation therapy (OAT) present special challenges in terms of rapid fluctuations in International Normalised Ratio (INR) values, interruption in daily life due to frequent hospital/doctor visits, and difficulties and pain in the performance of venepuncture. Optimised management of OAT improves the quality of treatment, potentially accomplished by new methods such as patient self-testing (PST) and patient self-management (PSM). A review was performed, identifying 11 trials with children and adolescents. All studies had different methodological problems, predominantly by being non-randomised trials. A total of 284 patients were included with a mean follow-up of 22 months, finding a time within therapeutic INR target range between 63% and 84%. The coagulometers used for estimating the INR values were found to have sufficient precision and accuracy for clinical use, but external quality control is probably advisable. It can be concluded that PST and PSM are at least as good treatment options as conventional management in highly selected children. Larger studies, preferably randomised, controlled trials using clinical endpoints, are obviously needed in order to elucidate whether these new regimens of treatment are superior to conventional management of oral anticoagulation therapy.