Yoshiaki Fukuhiro

Long-Term Results of Patchplasty for True Thoracic Aortic Aneurysm and the Effectiveness of Open Stents in Recurring Cases

2001年7月までに当科で経験した胸部真性大動脈瘤に対して,パッチ形成術を施行した24例を対象に検討した.部位およびサイズは,上行が1例,6.0cm,弓部が4例,2.5±0.5cm,遠位弓部が11例,4.7±1.7cm,下行が8例,3.7±0.5cmであった.病院死亡は3例,12.5%で,弓部,遠位弓部,下行がそれぞれ1例ずつ死亡した.その原因は,多臓器不全,脳梗塞,敗血症であった.遠隔成績は,追跡できた16例に対して検討したが,遠位弓部の2例で術後4年と術後6年で再発しただけで,そのほかには瘤再発に起因した死亡症例は認めなかった.再発症例に対しては,高度癒着の予想と呼吸機能低下により,open stent法を施行して,良好な経過を得た.遠位弓部の瘤再発症例においては,open stent法が有用と考えられた.

Implantation of a Ventricular Assist Device in Animals: Progress and Regress

Two types of ventricular assist device (VAD) were tested in vitro and in vivo. A biventricular bypass type total artificial heart utilizing two pusher-plate pumps was implanted in 11 sheep. Following the implantation, the animal’s heart was fibrillated. They survived for 2–48 days, with an average of 11.3 days. The pump flow ranged from 90 to 100ml/min per kg. Other hemodynamic data and the hematological data were normal, except for a low hemoglobin level. We have been developing an implantable motor-driven VAD in collaboration with the Baylor College of Medicine. This pump provided 81/min output against a mean afterload of 120 mmHg with a filling pressure of 20 mmHg. Nine in vivo studies have been conducted. Three sheep survived for 10–12 h. The pump flow ranged from 0.8 to 2.51/min. From these data, left atrial cannulation may not be sufficient to drain adequate blood flow into the pump.

Real-Time Measurement of Nitric Oxide in Coronary Outflow during Transient Myocardial Ischemia and Reperfusion

To examine the kinetics and determinants of the production and release of nitric oxide (NO) from a heart during transient myocardial ischemia and reperfusion, we directly measured NO in the coronary efluent from isolated beating rat hearts during reperfusion following transient myocardial ischemia using a newly developed NO microelectrode. Isolated rat hearts were perfused with an oxygenated Krebs-Henseleit buffered solution and were subjected to one-minute or ten-minute global ischemia followed by reperfusion at 100 cmH2O. The time course of measured NO current during reperfusion showed a monophasic pattern in the case of one-minute ischemia but a biphasic pattern in the case of ten-minute ischemia. Immediately after the onset of reperfusion, coronary flow increased almost stepwise after one-minute ischemia and gradually after ten-minute ischemia. After one-minute ischemia? measured NO current first stayed at a relatively low level and then gradually increased (monophasic pattern). After ten-minute ischemia, following a transient peak, the measured NO current gradually increased (biphasic pattern). There was an excellent linear relationship between coronary flow rate and the calculated amount of NO during the second rise of NO release in the case often-minute ischemia. These data suggest that the time course of NO release from a heart during reperfusion is determined by the production of NO during ischemia, which is ischemic-duration dependent, and by the reperfusion-rate dependent mechanism.