Mid-Term Clinical Results of Tissue-Engineered Vascular Autografts / 日本心臓血管外科学会雑誌

Prosthetic and bioprosthetic materials currently in use lack growth potential and therefore must be repeatedly replaced in pediatric patients as they grow. Tissue engineering is a new discipline that offers the potential for creating replacement structures from autologous cells and biodegradable polymer scaffolds. In May 2000, we initiated clinical application of tissue-engineered vascular grafts seeded with cultured cells. However, cell culturing is time-consuming, and xenoserum must be used. To overcome these disadvantages, we began to use bone marrow cells, readily available on the day of surgery, as a cell source. Since September 2001, tissue-engineered grafts seeded with autologous bone marrow cells have been implanted in 44 patients. The patients or their parents were fully informed and had given consent to the procedure. A 3 to 10ml/kg specimen of bone marrow was aspirated with the patient under general anesthesia before the skin incision. The polymer tube serving as a scaffold for the cells was composed of a copolymer of lactide and ε-caprolactone (50: 50) which degrades by hydrolysis. Polyglycolic or poly-l-lactic acid woven fabric was used for reinforcement. Twenty-six tissue-engineered conduits and 19 tissue-engineered patches were used for the repair of congenital heart defects. The patients' ages ranged from 1 to 24 years (median 7.4 years). All patients underwent a catheterization study, CT scan, or both, for evaluation after the operation. There were 4 late deaths due to heart failure with or without multiple organ failure or brain bleeding in this series; these were unrelated to the tissue-engineered graft function. One patient required percutaneous balloon angioplasty for tubular graft-stenosis and 4 patients for the stenosis of the patch-shaped tissue engineered material. Two patients required re-do operation; one for recurrent pulmonary stenosis and another for a resulting R-L shunt after the lateral tunnel method. Kaplan-Meier analysis in relation to patients' survival was 95% within 3 years. There was only 1 patient (who underwent a total cavo-pulmonary connection procedure) requiring re-intervention in the tubular graft group and the material-related event-free rate was 96% within 3 years. This tissueengineering approach may provide an important alternative to the use of prosthetic materials in the field of pediatric cardiovascular surgery. As it is living tissue, these vascular structures may have the potential for growth, repair, and remodeling. However, this approach is still in its infancy, further studies to resolve the problems presented, and longer follow-up in patients are necessary to confirm the durability of this approach.

A Case of the Senning Procedure in a Patient with Transposition of the Great Arteries with Intact Ventricular Septum and Bicuspid Pulmonary Valvular Stenosis Associated with Pulmonary Hypertension / 日本心臓血管外科学会雑誌

We performed the Senning operation and pulmonary valvotomy in an 11-month-old baby with transposition of the great arteries (TGA) with an intact ventricular septum (IVS), and bicuspid pulmonary valvular stenosis associated with pulmonary hypertension (PH). Preoperative catheterization showed a pressure gradient (PG) between the left ventricle (LV) and main pulmonary artery (MPA) of 35mmHg, mean pulmonary artery pressure (MPAP) of 56mmHg, and pulmonary vascular resistance (PVR) of 11.2unit·m². The pure oxygen inhalation test showed a decrease in MPAP from 56 to 38mmHg, and a decrease in PVR from 11.2 to 5.5 unit·m². We could not perform lung biopsy to determine the surgical indications in terms of PH due to preoperative progressive congestive heart failure in this patient. Postoperative catheterization (28 days after the Senning operation) showed a decrease in PG between the LV and MPA to 8mmHg, and MPAP also decreased to 17mmHg. Two radical operations were possible in this patient. One was the arterial switch operation (ASO), and the other was the atrial switch operation, i. e. the Senning or the Mustard operation. We selected the Senning operation because there was the possibility that the new aortic valve might develop persistent stenosis and regurgitation after ASO and pulmonary valvotomy. The Senning operation may be an alternative in selected patients with TGA with IVS and pulmonary valvular stenosis.

Surgical Treatment for Ruptured Abdominal Aortic Aneurysm / 日本心臓血管外科学会雑誌

Forty-four cases of ruptured abdominal aortic aneurysm were treated between January 1980 and December 1995. We classified the cases into three groups: Group I, 1980-1984; Group II, 1985-1989; and Group III, 1990-1995 and evaluated the surgical results, the preoperative states, the bleeding and blood transfusion volume and so on. The surgical results have improved every year and there were no surgical deaths during the past seven years. Most of the causes of previous surgical deaths were DIC (4 cases) and renal failure (3 cases). The volume of intraoperative bleeding was 7227.3±3293.4ml in Group I, 4176.0±2577.9ml in Group II and 1781.9±1877.0ml in Group III. The volume of intraoperative blood transfusion was 6975.5±2711.6ml in Group I, 4826.7±2596.6ml in Group II and 3542.4±1561.5ml in Group III. We decreased the volume of intraoperative blood transfusion significantly in Group III by using a Cell Saver. The surgical results have improved significantly due to the decrease of bleeding and blood transfusion under the rapid control of bleeding and the autotransfusion of shed blood using the Cell Saver. The technique of postoperative care also contributed to the more satisfactory results.

Surgical Repair of the Tetralogy of Fallot with Unusual Coronary Artery Distribution / 日本心臓血管外科学会雑誌

Extracardiac Conduit Repair (ECCR) is conventionally selected for the Tetralogy of Fallot (TOF) with unusual coronary artery distribution. However, in recent years conduit obstruction has been an important factor. Recently, we select the Right Ventricle Outflow Tract Reconstruction (RVOTR) using direct anastomosis between PA and RV as much as possible. In this paper, RVTOR was compared with ECCR. RVOT stenosis was relieved sufficiently and the ventricular function was well maintained after both surgical methods. We concluded that RVOTR should be selected instead of the ECCR because of the conduit obstruction.