Masaki Taira

Pulmonary Valve Replacement With Fresh Decellularized Pulmonary Allograft for Pulmonary Regurgitation After Tetralogy of Fallot Repair – First Case Report in Japan –

BACKGROUND Pulmonary valve replacement (PVR) is a common reoperation, typically required approximately 10 years following right ventricular outflow tract reconstruction and especially true in cases of tetralogy of Fallot. However, an improved prosthetic valve is required. METHODSANDRESULTS A fresh decellularized pulmonary allograft was used for PVR to correct pulmonary valve regurgitation in a 35-year-old man 33 years following tetralogy of Fallot repair. The postoperative course and short-term valve function were excellent. This is the first case of a decellularized pulmonary allograft in Japan. CONCLUSIONS Fresh decellularized pulmonary allografts have the potential to become a new source of material for PVR in patients who have undergone right ventricular outflow tract reconstruction.

Application of decellularized allograft for primary repair of congenital heart disease in Japan

A 6-month-old infant with a double outlet right ventricle, doubly committed ventricular septal defect, and right ventricle outflow tract (RVOT) stenosis underwent intracardiac repair with RVOT reconstruction using a fresh decellularized allograft derived from a 1-year-old heart transplant recipient in Japan. Early postoperative evaluation via echocardiography and cardiac magnetic resonance imaging revealed that the pulmonary allograft and cardiac function were stable. This is the first case report on using a decellularized heart valve, which was resected from a heart transplant recipient, for primary repair of congenital heart disease in Japan.

Aggressive Surgical Resection of Pulmonary Artery Intimal Sarcoma

Intimal sarcoma of the pulmonary artery is a rare and highly malignant neoplasm. This report describes a case of a 30-year-old woman with an extensive right pulmonary artery tumor who underwent an emergency operation. The tumor was aggressively resected with right pneumonectomy and reconstruction of the right ventricle outflow tract and left pulmonary artery. Although the resected margin at the left pulmonary artery was positive for disease, as confirmed by mouse double minute type 2 homologue staining, she is doing well and remains free of relapse at 16 months after the operation.

Application of a Fresh Decellularized Pulmonary Allograft for Pulmonary Valve Replacement in Japan

BACKGROUND Tissue engineering has advanced the technique of decellularization of the heart valve. The valve is reseeded with the patients own cells after implantation with suppression of immunologic reactions. The same advantage has been reported for fresh decellularized heart valves, and more than 10 years of excellent outcomes have been achieved. We began performing such heart valve implantations in 2013 as part of a clinical study at Osaka University. We report our evaluation of the safety and efficacy of heart valve implantation.Methods and Results:Human pulmonary valves from the German Society for Tissue Transplantation (n=2) or from Japanese heart transplant recipient heart (n=4) were used to make decellularized heart valves; the decellularization process was the same as that used in Europe. Valves were implanted in 5 adults with pulmonary valve insufficiency after tetralogy of Fallot repair and in 1 infant with a double-outlet right ventricle with pulmonary stenosis. Postoperative echocardiography and cardiac magnetic resonance imaging revealed that the valve and ventricular function were significantly improved and maintained postoperatively. CONCLUSIONS Decellularized heart valves could be the new material used as artificial heart valves. Pulmonary allografts derived from the hearts of heart transplant recipients are considered to be useful material for decellularized heart valves. The application of this valve to Japanese clinical circumstances and using the hearts of heart transplant recipients is considered to be very significant.

Clinical Predictors of Right Ventricular Myocardial Fibrosis in Patients With Repaired Tetralogy of Fallot

BACKGROUND This study aimed to identify the clinical predictors of the degree of right ventricular (RV) myocardial fibrosis in patients with repaired tetralogy of Fallot (TOF) with special focus on the RV pressure load.Methods and Results:From April 2004 to March 2017, 30 patients with repaired TOF underwent pulmonary valve replacement and concomitant RV myocardial biopsy. The stroke volume ratio (RV stroke volume/left ventricular stroke volume), RV end-diastolic volume index, and right-to-left ventricular systolic pressure ratio were evaluated with respect to their prognostic value for the degree of RV myocardial fibrosis. Significant positive linear correlations were detected between the stroke volume ratio and the degree of RV myocardial fibrosis (P=0.003, r=0.52). Patients with a right-to-left ventricular systolic pressure ratio >0.45 showed a significantly greater degree of RV myocardial fibrosis under an equivalent stroke volume ratio. CONCLUSIONS Under conditions of RV volume overload, a right-to-left ventricular systolic pressure ratio >0.45 was a predisposing factor for progression of RV myocardial fibrosis in patients with repaired TOF.