Setsuro Imawaki

Development of a fistula between an internal mammary artery graft and the pulmonary vasculature following coronary artery bypass grafting: Report of a case

We report herein the rare case of a 56-year-old man who gradually developed congestive cardiac failure 6 months after undergoing coronary artery bypass grafting and was found to have a fistula between the internal mammary artery and the pulmonary artery of the upper lobe diagnosed by selective left internal mammary arteriogram. A second sternotomy was performed and demonstrated dense adhesion between the fissure surrounding the internal mammary artery and the upper lobe, and the fistula was resected. We believe that the patients increasing cardiac failure was almost certainly caused by coronary steal.

Decrease in aortic distensibility after an extended aortic reconstruction for Marfan's syndrome as a cause of postoperative acute aortic dissection DeBakey type I: A report of two cases

Two cases of Marfans syndrome underwent a reconstruction of the abdominal aorta and descending thoracic aorta. A replacement of the abdominal aorta with visceral arteries as well as a wrapping of the descending thoracic aorta was performed in case 1 while a reconstruction of the descending thoracic aorta and infra-renal abdominal aorta was done in case 2. After the reconstruction, both cases developed acute aortic dissection DeBakey type I. Another reconstruction of the ascending aorta was then urgently performed. Cardiac catheterization after the second operation in case 1 revealed that the distensibility of the aorta had disappeared at the location of the vascular prosthesis while it had also decreased at the wrapped portion, and the maximum dp/dt of the ascending aorta also increased. Increases in the pulse pressure and pulse rate after the first operation were observed in both cases. These hemodynamic changes, which were produced by a decreased distensibility of the reconstructed aorta, increased the mechanical stress to the native aortic wall, and may have been one of the causes of acute aortic dissection DeBakey type I occurring after reconstruction with a prosthesis.

A pulsatile cardiopulmonary bypass system that prevents negative pressure at the membrane oxygenator

Negative pressure is a problem in pulsatile cardiopulmonary bypass (CPB). To avoid this, the authors designed a pulsatile CPB system containing a Sarns centrifugal pump (CP) and a Univox membrane oxygenator, in which the inertial flow is not obstructed by the CP. In both an in vitro study and a clinical study, negative pressure was not observed in the arterial line of the CPB circuit when this system was used. When a roller pump (RP) was used, however, instead of a CP, negative pressure did occur. In a clinical study using this system, mean pulse pressure was 36 mmHg and hemolysis, expressed as the rate of rise in plasma free hemoglobin from 10 to 70 min of CPB, was 26.2 mg/dl/hr, which did not exceed that seen with a pulsatile CPB using an RP instead of a CP. The hemolysis seen in the study caused no clinical problems. Thus, pulsatile CPB using a CP and Univox membrane oxygenator should be considered for clinical use to prevent the occurrence of negative pressure.

Effects of left intraatrial infusion of prostaglandin E1 after open-heart surgery

The hemodynamic effects of a left intraatrial infusion of prostaglandin E1 (PGE1) given to ten patients after open-heart surgery (LA group), were compared with those following no treatment in a control group of ten patients, and to those following a right intraatrial infusion given to another ten patients (RA group). PGE1 was infused at a rate of 0.03 μg/kg/min in the RA group and at 0.003 μg/kg/min in the LA group, and hemodynamics were measured immediately after surgery, then 3, 6, and 12 h after the PGE1 infusion was commenced. The heart rate, right atrial pressure, left atrial pressure, and mean pulmonary arterial pressure remained almost unchanged in all three groups; however, the mean radial arterial pressure and systemic vascular resistance index decreased, and the cardiac index increased in the RA and LA groups. The pulmonary vascular resistance index decreased only in the LA group. Thus, a much smaller dose of PGE1, being one-tenth of that used for the right atrial infusion, administered directly into the left atrium yielded almost the same hemodynamic effects as the larger dose infused into the right atrium. Furthermore, this method of infusing PGE1 is safe, efficacious, and cost-efficient.

Chordal reconstruction with polytetrafluoroethylene (PTFE) sutures for mitral regurgitation

Chordal reconstruction of the mitral valve using CV4 or CV5 polytetrafluoroethylene (PTFE) (GoreTex, Flagstaff, AZ, USA) sutures was performed in seven patients with mitral regurgitation (MR) to ascertain its efficacy. The MR had been caused by prolapse of the anterior leaflet in three patients, the posterior leaflet in two, and both leaflets in two; five of the patients had an MR of grade III or IV. There was one hospital death, which occurred in a patient whose MR had resulted from papillary muscle dysfunction caused by a myocardial infarction (MI). Chordal reconstruction failed and was converted to a mitral valve replacement in two patients, one of whom had suffered a MI and another who had a congenital papillary muscle anomaly. The remaining five patients all underwent successful chordal reconstruction with PTFE sutures, resulting in the disappearance of the MR in two patients and an improvement to grade I in three patients. Although the longest follow-up period has been only 1 year, the MR has not worsened. This technique is relatively easy to perform, and allows almost all the mitral apparatus to remain in situ, while enabling repair of the mitral valve, regardless of the state of the diseased chordae.