Yutaka Kanki

Intraatrial rerouting by atrial flaps for partial anomalous pulmonary venous return

We report a new surgical correction technique using an autologous atrial septal flap and anterolateral right atrial wall in a 3-year-old girl with partial anomalous pulmonary venous return and lower margin atrial septal defect. The patient recovered smoothly and is doing well 3 years after the operation.

An autologous connective tissue tube with high healing ability as a small diameter vascular substitute with temporary antithrombogenicity

Although autologous connective tissue grafts (ACTG) are an ideal vascular substitute, they have not yet been used as small diameter vascular grafts because of thrombogenicity. We reported on ACTGs in which mesh tubes were fabricated from ultra-fine polyester fibers (UFPF) and used as a framework. Antithrombogenicity was established using an original heparinization method, with a 50% patency 1 month postimplantation. Early failure of these grafts was caused mainly by loss of antithrombogenicity before development of endothelialization on the inner surface. In this study, higher concentrations of heparin were used for in situ heparinization of the grafts before implantation in combination with antiplatelet therapy (cilostazol, OPC-13013 for the first month after substitution for canine carotid arteries. As a result, more complete healing of the grafts was attained, with a patency rate of 63% at 1 month, when small doses of antiplatelet agents were used. More intensive antiplatelet therapy resulted in impairment of graft healing, causing hematomas around the grafts. Thus, optimal doses of antiplatelet agents remain uncertain.

A pulsatile pump for cardiopulmonary bypass and its clinical use

A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.81/min to 5.71/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients’ own hearts.