Hideto Ozawa

Contractility–Afterload Mismatch in Patients With Protein-Losing Enteropathy After the Fontan Operation

This study aimed to clarify the relationship between onset of protein-losing enteropathy (PLE) and Fontan circulation, with special reference to the development of contractility–afterload mismatch. The PLE group comprised 9 patients who experienced PLE after undergoing the Fontan operation, and the control group consisted of 32 patients had did not experienced PLE more than 10 years after the Fontan operation. The study compared the pre- and postoperative values of arterial elastance (Ea), end-systolic elastance (Ees), and contractility–afterload mismatch (Ea/Ees). Furthermore, the variations in the values were examined during the preoperative, postoperative, and midterm postoperative periods in seven PLE patients who underwent cardiac catheterization at the onset of PLE and during the pre- and postintervention periods in three PLE patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE. Comparison of the values obtained before and after Fontan operations showed that the Ea values increased significantly in the PLE group. However, the pre- and postoperative Ees values did not differ in the two groups. During the postoperative period, Ea/Ees increased significantly, and the Ea and Ea/Ees values increased continuously until the onset of PLE in the PLE group. In the patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE, the Ea/Ees decreased significantly, and the serum albumin levels improved after the intervention. Contractility–afterload mismatch, mainly caused by the increase in the afterload of the systemic ventricle, may have an important role in the development of PLE after the Fontan operation.

Use of the Damus-Kaye-Stansel procedure prevents increased ventricular strain in Fontan candidates

OBJECTIVES In Fontan candidates, we have recently been aggressively performing the Damus-Kaye-Stansel procedure (DKS) to prevent increased afterload on the systemic ventricle. The present study investigated the efficacy of the DKS procedure in terms of the ventricular function following a Fontan operation. METHODS Patients undergoing a Fontan operation were divided into three groups: DKS performed at the time of the bidirectional Glenn or Fontan operation (DKS group, n = 25); DKS not performed at any stage due to mild pulmonary stenosis (PS) (PS group, n = 23) and DKS not performed due to pulmonary atresia (PA) or severe PS (PA group, n = 24). Ventricular function, afterload on the systemic ventricle and atrioventricular valve regurgitation were compared between groups. RESULTS Cardiac catheterization before a Glenn or Fontan operation and at 1-year following the Fontan revealed significantly decreased ventricular end-diastolic pressure in the DKS group. The ventricular ejection fraction was significantly deteriorated in the PS group. Effective arterial elastance, as an index of total ventricular afterload, was increased after a Fontan in all groups, with a substantial increase in the PS group. As an index of ventricular mechanical efficiency, ventriculoarterial coupling was significantly increased only in the PS group. Cardiac ultrasonography revealed atrioventricular valve regurgitation above grade 3 persisting in many patients from the PS group. Semilunar valve function after DKS operation did not progress to moderate or worse in any patients. CONCLUSIONS The proactive performance of the DKS procedure prevents increased ventricular afterload, avoiding deterioration of cardiac function and contributing to improved long-term results following a Fontan operation.

Staged Starnes Operation Preserving Patent Ductus Arteriosus for Neonates with Ebstein's Anomaly and Pulmonary Atresia.

We herein reported 2 successful neonates with Ebstein’s anomaly and small pulmonary arteries undergoing Starnes operation preserving the patent ductus arteriosus. Subsequent Blalock-Taussig shunt was carried out 1 or 2 months after the first surgery. One case had already undergone a successful Fontan operation, and the other had a successful bidirectional Glenn shunt so far. This staged Starnes strategy might be a safe and simple choice for neonates with Ebstein’s anomaly and small pulmonary arteries.

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.

Application of hybrid Stage I palliation for patients with two ventricular cavities and hypoplastic left heart structures

OBJECTIVES To assess the feasibility of hybrid Stage I palliation consisting of bilateral pulmonary artery bandings and ductal stenting for patients with 2 ventricular cavities and hypoplastic left heart structures. METHODS Eleven consecutive patients who underwent hybrid Stage I palliation between 2010 and 2017 were enrolled. The diagnoses were interrupted aortic arch/coarctation of the aorta, ventricular septal defect and significant left ventricular (LV) outflow tract obstruction in 5 patients, critical aortic stenosis and reduced LV contraction in 3 patients and hypoplastic left heart complex in 3 patients. RESULTS The median age at definitive surgery was 12 months (range 6-22 months). During the mean follow-up period of 24 months (range 9-83 months) following the definitive surgery, there was 1 death. Two patients with interrupted aortic arch/coarctation of the aorta did not undergo the Yasui operation but underwent arch repair and ventricular septal defect closure after the growth of the aortic valve and LV outflow tract. For 2 of the 3 patients with critical aortic stenosis, biventricular repair was performed. Of the 3 patients with hypoplastic left heart complex, 2 patients showed growth of the mitral valve and left ventricle following LV rehabilitation by balloon pulmonary artery dilatation or surgical debanding of the banded pulmonary arteries and subsequently underwent biventricular repair, which resulted in 1 death. CONCLUSIONS Hybrid Stage I palliation would be a safe and beneficial treatment for patients with 2 ventricles, as a bridge to decide whether and how to achieve a biventricular repair and whether it should be preceded by a preliminary LV rehabilitation.

Utility of a super-flexible three-dimensional printed heart model in congenital heart surgery†

OBJECTIVES The objective of this study was to assess the utility of 3D printed heart models of congenital heart disease for preoperative surgical simulation. METHODS Twenty patient-specific 3D models were created between March 2015 and August 2017. All operations were performed by a young consultant surgeon who had no prior experience with complex biventricular repair. All 15 patients with balanced ventricles had outflow tract malformations (double-outlet right ventricle in 7 patients, congenitally corrected transposition of great arteries in 5, transposition of great arteries in 1, interrupted aortic arch Type B in 1, tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries in 1). One patient had hypoplastic left heart complex, and the remaining 4 patients had a functional single ventricle. The median age at operation was 1.4 (range 0.1-5.9) years. Based on a multislice computed tomography data set, the 3D models were made of polyurethane resins using stereolithography as the printing technology and vacuum casting as the manufacturing method. RESULTS All but 4 patients with a functional single ventricle underwent complete biventricular repair. The median cardiopulmonary bypass time and aortic cross-clamp time were 345 (110-570) min and 114 (35-293) min, respectively. During the median follow-up period of 1.3 (0.1-2.5) years, no mortality was observed. None of the patients experienced surgical heart block or systemic ventricular outflow tract obstruction. CONCLUSIONS Three-dimensional printed heart models showed potential utility, especially in understanding the relationship between intraventricular communications and great vessels, as well as in simulation for creating intracardiac pathways.

Venovenous malformation developed prior to a Kawashima operation in a patient with an interrupted inferior vena cava

An 11-month-old girl with an unbalanced atrioventricular septal defect, coarctation of the aorta and an interrupted inferior vena cava with hemiazygos continuation post-surgical status of coarctation repair and pulmonary artery banding underwent a Kawashima operation. Severe hypoxia occurred immediately after she was weaned from cardiopulmonary bypass, which was successfully resolved by the ligation of the hemiazygos vein. Postoperative enhanced computed tomography detected significant venovenous malformation from the hemiazygos vein to the left renal vein.

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.