Haruhiko Okumura

Clinical results of coronary artery bypass grafting with use of the internal thoracic artery under low free flow conditions

OBJECTIVEnEven when left internal thoracic artery flow is very low, we have used the artery for grafting without any further maneuvers. In this study, we investigated the clinical results of coronary bypass surgery using the left internal thoracic artery with low free flow.nnnMETHODSnA total of 163 patients were divided into 2 groups: group L (n = 43) had free flow of 20 mL/min or less and group H (n = 120) had free flow of more than 20 mL/min. We performed a comparative study on the basis of coronary angiography and pulsed Doppler echocardiography. Furthermore, 12 months postoperative graft angiography was carried out in 11 patients from group L.nnnRESULTSnNo patient had low output syndrome or perioperative myocardial infarction. One month after the operation, 3 cases of graft occlusion and 9 cases of the string sign were identified in group H. However, group L had no graft occlusion and only 1 case of the string sign. The 1-month postoperative Doppler echocardiographic study showed no significant differences in the diastolic fraction of velocity time integrals and the diastolic/systolic peak velocity ratio of the grafts. In the 11 patients undergoing angiography after 1 year, graft patency was excellent. Moreover, the graft diameter was significantly larger than it was 1 month after the operation.nnnCONCLUSIONnThese results suggest that the left internal thoracic artery can be used for coronary artery bypass grafting even when the flow is less than 20 mL/min.

Experiences of Postcardiotomy Assist: Pneumatic Ventricular Assist Device or Venoarterial Bypass with Percutaneous Cardiopulmonary Support

From October 1982 to the present, 16 patients have been supported by a pneumatic ventricular assist device (VAD). Since April 1990, we have introduced a venoarterial bypass (VAB) with percutaneous cardiopulmonary support (PCPS) system. This PCPS system was used in 12 patients. The long-term survival rate of PCPS cases (41%) was much better than that of VAD cases (19%). The main cause of death in VAD cases was multiple organ failure (MOF). Although VAB was initiated more recently than VAD, the duration on support was longer in the VAD group than in the VAB group. Because of the longer support duration and the presence of many patients with MOF, coagulopathy deteriorated more readily in the VAD group than in the VAB group. In the case of postcardiotomy cardiopulmonary bypass weaning or low-output syndrome (LOS), the VAB with PCPS system should be applied first under intraaortic balloon pumping assist because of its simplicity and low cost. Thereafter, VAD should be applied in cases refractory to VAB support.

Clinical evaluation of the Gyro Pump C1E3 as a cardiopulmonary bypass pump.

The Gyro Pump C1E3 is a new centrifugal pump with numerous features, including a ceramic pivot bearing system, secondary vanes, and an eccentric inlet port. To evaluate its biocompatibility, antithrombogenicity, and produced hemolysis, we used the Gyro Pump during cardiopulmonary bypass (CPB) for coronary artery bypass grafting (CABG) cases to compare it with the BioMedicus pump. From September 1998 to February 1999, 30 consecutive patients underwent CABG under conventional CPB. Fifteen patients were supported by the Gyro Pump C1E3 (Group G), and the remaining 15 patients, by a BioMedicus BP-80 pump (Group B). In both groups, flow rate was equivalent. Blood samples were taken as follows: preoperative, 60 minutes after the end of the procedure, and at postoperative days (POD) 0, 1, and 2. We evaluated the plasma free hemoglobin (free Hb) as an indication of hemolysis; beta-thromboglobulin (beta-TG) and platelet factor four (PF-4) as an indication of platelet deterioration; C3, C4, CH50 for complement activation; coagulation parameters, fibrinolytic factor, thrombomodulin, nitric oxide (NO), and endothelin as an indication of endothelial deterioration. This was the first clinical sized Gyro Pump CIE3. De-airing from the pump was easily accomplished via the eccentric oblique inlet port. The system, including its console, was easily and simply controlled. Perioperative laboratory data were not markedly changed in either group with demonstrated equivalence for biocompatibility and hemolysis. After pumping, no thrombus formation or pivot wear were observed inside the pump. This atraumatic, small centrifugal pump appears well suited not only for CPB but also for circulatory support.

Clinical Experience with Percutaneous Cardiopulmonary in Postcardiotomy Cardiogenic Shock

From April 1990 to June 1996, 14 patients who had been suffering from post-cardiotomy cardiogenic shock were supported by a heparin-coated percutaneous cardiopulmonary support (PCPS) system. Of these patients, 8 (57%) (group I) could be weaned from PCPS, and 6 (group II) could not. Of the group I patients, 7 were discharged from our hospital (long-term survival rate 50%). One patient died from cardiac rupture due to severe myocardial infarction. In group II, cerebral vascular damage was recognized in two cases and renal failure in three. As for aortic crossfclamp time and cardiopulmonary bypass (CPB) time, there were no significant differences between the groups. However, the time delay from initiation of CPB to that of PCPS in group I (212 min) was significantly shorter than that in group II (390min). This heparin-coated PCPS system was very simple and easy to control. It demonstrated long-term biocompatibility without systemic heparinization. Quicker application of this system is expected to play an important role in preventing severe complications, such as multisystem organ failure, and to obtain better clinical results.

Retrospective analysis of the clinical trends and current indications for perioperative intraaortic balloon pumping in high-risk coronary artery bypass surgery

We clinically evaluated the current indications for perioperative intraaortic balloon pumping (IABP) in high-risk patients undergoing coronary artery bypass grafting (CABG). Over the past 22 years, 196 CABG patients received perioperative IABP at our institution. We divided the 22 years into periods I–IV (earliest to latest) and investigated the annual changes in the indications for and mortality from IABP. In periods I and II, IABP was mainly employed for postoperative low-output syndrome (LOS) or perioperative myocardial infarction (PMI). The hospital mortality rate was 13.2%–18.5%. In period III, the mortality rate was markedly reduced by the use of preoperative scheduled IABP. In period IV, however, scheduled IABP was used less often for high-risk CABG, and IABP was mainly employed in patients having emergency CABG for acute coronary syndrome (ACS). The hospital mortality rate was reduced to 3.7%. In the last 2 years, 19 (65.5%) of 29 patients who received preoperative IABP had emergency CABG for ACS, while 27 high-risk CABG patients with poor left ventricular (LV) function or left main trunk (LMT) disease were treated successfully without scheduled IABP. There were no significant differences between the IABP and non-IABP patients in age, sex, number of bypasses, and aortic cross-clamp time. Because of improvements in anesthesia, operative techniques, perioperative management, and cardioplegic solutions, preoperative support with IABP is less often needed for high-risk CABG, except in patients undergoing emergency surgery for ACS.

Post-Cardiotomy Assist: Pneumatic VAD or PCPS-VAB?

Several types of mechanical circulatory support devices are currently available for profound heart failure in conjunction with open heart operations [1,2]. Pneumatic ventricular assist devices (VADs) have been employed postoperatively in more than 200 patients in Japan and have established a reputation as powerful assist devices in the treatment of heart failure [3]. In recent years, percutanous cardiopulmonary support (PCPS) systems have been introduced as easily used support devices in both surgical and medical fields [4]. As of September 1994, pneumatic VADs had been employed in 16 postcardiotomy patients in our department, and a PCPS system for veno-arterial bypass (VAB) had been employed in 14 postcardiotomy patients. Here, we review our experience with the pneumatic VAD system and the PCPS-VAB system and compare the results to evaluate their feasibility for post-cardiotomy mechanical support.