Kazuhiro Kitaura

Comparison of hemodynamic data before and after corrective surgery for Down's syndrome and ventricular septal defect

SummaryLeft ventricular function and the extent of pulmonary vascular disease were studied in 18 children with Downs syndrome and 20 children without Downs syndrome who underwent corrective surgery for ventricular septal defect (VSD) and severe pulmonary hypertension. This study was conducted between 1985 and 1993. All patients underwent routine cardiac catheterization preoperatively and postoperatively (mean, 11.4 months after surgery). Left ventricular function was estimated using cineangiographic levograms. In both groups, the pulmonary-to-systemic arterial pressure ratio (Pp/Ps) and pulmonary vascular resistance (PVR) were significantly lower after surgery (P < 0.05). Postoperative improvement was more remarkable in the non-Down group (P < 0.05). Left ventricular end-diastolic volume (percent of normal) (LVEDV%N) was significantly lower after surgery in both groups (P < 0.01). The left ventricular stroke work-to-end-diastolic volume ratio (LVSW/EDV) was significantly higher after surgery in the non-Down group only (P < 0.01). Postoperative left ventricular ejection fraction (LVEF) was significantly lower in the Down group than in the non-Down group (P < 0.01). Some degree of irreversible pulmonary vascular disease was present after repair of VSD in patients with Downs syndrome. In the Down group, there were no significant changes in left ventricular function after surgery, despite the relief of volume overload. These results suggest that early diagnosis and surgical repair are key elements in the management of patients with Downs syndrome and VSD.

Effect of CABG on coronary flow reserve in atresia of the left coronary ostium.

We evaluated the change of coronary flow reserve using a Doppler guidewire before and after coronary artery bypass grafting to assess the coronary hemodynamic effect of surgical revascularization in a 13-year-old boy with congenital atresia of the left coronary ostium, which is one of the rarest of the congenital coronary anomalies. Coronary flow reserve in the right coronary artery and left anterior descending artery increased significantly after coronary revascularization, and a microvascular bed developed in the left anterior descending artery.

Surgical palliation of cardiac malformations associated with right isomerism.

Between 1985 and 1993, palliative surgery was performed on 13 pediatric patients who had complex cardiovascular anomalies associated with right isomerism. The patients included two neonates, ten infants, and one child who were divided into two groups according to whether or not a total anomalous pulmonary venous connection (TAPVC) was present. Group 1 consisted of six patients with TAPVC and group 2 consisted of seven patients without TAPVC. In group 1, the surgical procedures involved TAPVC repair alone in two patients, combined TAPVC repair with a modified Blalock-Taussig shunt in two, combined TAPVC repair with pulmonary artery banding in one, and a modified Blalock-Taussig shunt alone in one. There were five hospital deaths and one late death in this group: pulmonary venous obstruction in two patients, perioperative myocardial failure in the two neonates, and congestive heart failure caused by increased pulmonary blood flow in two patients. In group 2, all the patients underwent systemic-pulmonary artery shunts, and there was one hospital death and three late deaths, the causes of which were unknown in two patients, and shunt failure and pneumonia in one patient each. These results suggest that surgical palliation for right isomerism produces poor results in young infants with obstructed TAPVC. Thus, we conclude that TAPVC repair should be performed without delay if pulmonary venous obstruction has been diagnosed clinically. Resolving pulmonary venous obstruction without cardiopulmonary bypass (CPB) may be preferable for infants, considering their difficult management. The systemic-pulmonary artery shunt should be of the low-calibrated type, especially if common atrioventricular valve regurgitation exists. If infants survive the surgery, they must be carefully followed up for a long period due to the risk of sudden death or infection.

A case of Successfully Operated Pelvic Arteriovenous Malformation.

動静脈奇形 (AVM) は四肢や脳, 肺などに発症することが多 く骨盤内のものは少ない. 今回われわれ は, そのような骨盤内AVMの 一例に対 して根治せしめたので報告する. 症例は59歳 女性で, 主訴は 右下腹部腫瘤である. 骨盤部CTと 血管造影で異常血管瘤を伴うAVMと 診断した. 手術は術前より 診断しえた feeding artery である右内腸骨動脈と右腰動脈および右尿管動脈を結紮し, 右腎動脈から のAVMと 瘤を摘出した. 術後の血管造影では, 右内腸骨動脈末梢の正常血管は左側からの側副血行 路により造影されたが, AVMは 完全に消失していた. 近年AVMに 対する治療法としてカテーテル による塞栓術が頻用されているが, 本症例のように流出系に異常血管瘤を伴う場合には, 塞栓術は危 険を伴い, 不確実である. このような症例には feeding artery を結紮し瘤を切除することが, より確 実で安全であり, 今回のような外科的摘出術が第一選択になると思われる. 日心外会誌23巻2号: 125-128 (1994)

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.