Saeki Tsukamoto

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.

EFFECTS OF CONCOMITANT USAGE OF MILRINONE AND CATECHOLAMINE FOR WEANING FROM CARDIOPULMONARY BYPASS

To estimate the effectiveness of concomitant usage of milrinone and catecholamine for weaning from cardiopulmonary bypass (CPB), a clinical study was made, in elective coronary artery bypass grafting (CABG) cases. 24 consecutive patients underwent elective CABG in our institute. In all cases, moderate hypothermia and cardioplegic(St. Thomas solution) cardiac arrest were performed. In 12 cases, continuous intravenous 0.25 microgram/kg/min of milrinone, 3 micrograms/kg/min of dobutamine (DOB) and dopamine (DOA) as the initial doses, were used concomitantly as inotropic agents (Group-I). The same initial doses of catecholamine (DOB and DOA) as the Group-I were administered in another 12 patients (Group-II). When the pump flow of CPB decreased to a half, these drugs were administered in both groups. Hemodynamic data were measured before CPB, just after operation, 3, 6, 12, 24, 48, and 72 hours after operation. There were no significant differences in aortic and pulmonary artery pressure between both groups. However, cardiac index (CI) of the Group-I demonstrated significantly (p < 0.01) higher values than that of Group-II until 24 hours after surgery. Systemic vascular resistance index (SVRI) of the Group-I demonstrated significantly (p < 0.01) lower value than that of Group-II from 3 to 12 hours after operation. There were no significant differences in oxygen delivery (DO2) and oxygen consumption (VO2) between both groups. These results suggested that concomitant usage of milrinone and low dose catecholamine increased CI and decreased SVRI, and made weaning from CPB very easy, demonstrating excellent hemodynamics. This high potential phosphodiesterase inhibitor may be suitable for not only weaning from CPB but also post-cardiotomy cardiogenic shock.

Removal of a Chronically Infected Bipolar Pacemaker Electrode

A chronic infected bipolar pacemaker electrode with a fin tip was successfully removed 7 years and 9 months after its original implantation from a 72-year-old Japanese man, using the Cook pacemaker lead extraction system. The locking stylet could not advance to the lead tip over the positive pole because of firm adhesions. Because the scar tissue between the positive pole and myocardium could not be freed by the inner sheath, it was disrupted by the slanted end of the outer sheath. The firmest adhesion was on the positive pole, not on the fin tip. The complete extraction success rate of bipolar tined or fin leads is worse than for other types of leads. When extracting a bipolar pacemaker lead, dissection of the positive pole from scar tissue should be taken into account in addition to the lead tip. Rotating the slanted end of the outer sheath is a useful technique when dissecting firm adhesions.

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.

Abdominal Aortic Aneurysm Accompanied by Aortic Dissection

大動脈解離が及んだ腹部大動脈瘤3例を経験した.3例中2例を腸管壊死により失ったが,このうち1例は解離が腹部大動脈瘤に進展したために破裂した症例で,人工血管の中枢側吻合にさいして開窓術を行わなかったことによる上腸間膜動脈の血流障害が原因と考えられた.もう1例の死亡例は開窓術を行ったのちに人工血管置換術を行ったが,剖検の結果,グラフトの吻合には問題なかったものの,内腸骨動脈の閉塞が原因で下行結腸からS状結腸が壊死に陥り死亡したと判明した.生存例では開窓術ののち,人工血管置換術を施行し経過は良好であった.手術時期は大動脈解離を発症した急性期では血管壁が脆弱であることから,破裂例およびmalperfusionによる虚血症状が認められる症例を除き,発症から1ヵ月の期間をおくことが望ましいと思われる.また慢性期では開窓術の安全性は高く,これを行うべきであり,また急性期であっても可能なかぎり行うべきである.

Aortic Dissection Complicated by Atherosclerotic Aneurysm

1999年1月1日から2001年12月31日までに当科で経験した大動脈解離症例152例(Stanford A型77例,Stanford B型75例)のうち真性大動脈瘤の合併は25例(16.4%)にみられ,A型解離が10例(13.0%),B型解離が15例(20.0%)であった.発症年齢は71.4±9.8歳であり,真性大動脈瘤を合併した大動脈解離症例の手術では高齢であることを考慮して治療方針,術式を決定する必要があると考えられた.大腿動脈送血で体外循環を行うさいは,瘤を介して脳へ血液が送られることが多いため,人工心肺開始時に順行性送血に比べて送血を緩徐に行い,また心室細動となったのちは灌流圧を低下させるようにし,粥腫が脳血管へ流れ込むのを予防,さらに末梢側吻合後は送血分枝から送血することなどが重要であると思われた.また紡錘状大動脈瘤が解離のエントリーとなったのは152例中3例(2.0%)で,大動脈解離が大動脈瘤に接して存在した11例中2例の嚢状瘤は解離の進行を停止させたが,9例の紡錘状瘤は停止させることはなく,大動脈瘤は形態により解離に及ぼす作用が異なると考えられた.大動脈瘤と大動脈解離が異所性に併存する症例においても再解離により瘤内に解離が進入することがあり,大動脈解離を保存的に治療する場合であっても真性瘤の手術時期の決定は慎重に行うべきである.

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.