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Biomedical subjects

K Suma

Publications and source records attributed to K Suma.

138 records · Page 8Linked to original sources

Development of a new circulatory assist method with the combined effects of intra-aortic balloon pumping and counter pulsation. First report.

Current circulatory assist methods, such as intra-aortic balloon pumping (IABP), are not always adequate to save acute circulatory failure patients. Therefore, a stronger, percutaneously accessible method is required. We found that the combination of IABP and CP generated a profound circulatory assist effect, and we have consequently developed a new assist system in this study. A sac type blood pump with a volume of 20 ml and a single port without a valve, was developed for CP. In the mock circulatory test, a 20 ml stroke volume was obtained using a cannula with a 5 mm diameter under the following driving conditions: air pressure = 200/-100 mmHg; S/D = 50%; pulse rate = 100 bpm. In vivo experiments were performed using four mongrel dogs with body weights of 12-20 kg. A cannula for CP was inserted via the brachial artery or subclavian artery into the aortic root. The pump flow (PF), coronary artery flow (CF), renal arterial flow (RF), and aortic pressure (AP) were measured, and the combined effects of IABP and CP were compared with their individual effects. In the most effective case, a marked increase in diastolic AP (60%), cardiac output (40%), and CF (100%) was obtained by the combination of IABP and CP, which produced a remarkable effect compared with the single use of IABP and CP. There was no negative effect on RF by this assist method. As this new circulatory support system has many circulatory assist effects, and is percutaneously accessible, it will be available for clinical use.

Animals↗

Non-reversed saphenous vein grafting: an improved technique or aortocoronary bypass surgery.

Prevention of graft failure produced by intervening valves in reversed segments of saphenous veins has been achieved by a new method of aortocoronary bypass surgery employing non-reversed, valve-free segments of vein. The large cephalic end of the greater saphenous vein segments is anastomosed to the aorta. The somewhat smaller, caudal end of the venous segment is anastomosed to the coronary artery, thereby reducing veno-coronary size discrepancy. Graft stenosis and thrombosis caused by venous valves is avoided.

Adult↗

Surgical experience with coronary arterial sequelae of Kawasaki disease in children.

The coronary arterial sequelae due to Kawasaki disease have been treated surgically in five children ranged from 6 to 9 years old. The procedures were aortocoronary bypass surgery in all cases, coronary artery aneurysmectomy in one case and left ventricular aneurysmectomy in one case. The early results of operated cases have been good with the graft patency of 86% confirmed by angiography one month after surgery. The characteristic features of coronary artery damage in patients with Kawasaki disease are coronary artery aneurysms, which manifest wall irregularity, thrombus, calcification and stenosis. The significant stenosis of coronary artery could often be observed at the inlet or outlet of the aneurysm in major coronary artery branches. Although the early results of aortocoronary bypass surgery in the children with Kawasaki disease have been good, long-term follow up is mandatory to investigate the status of autogenous saphenous vein grafted in children.

Angiocardiography↗

Noncontact transducer for monitoring blood temperature during extracorporeal circulation.

A zero-heat-flow transducer was designed to monitor blood temperature during extracorporeal circulation. The probe was covered with a thick metal shell that was heated or cooled to match the surface temperature of the circulation tube, causing the net heat flow across theprobe to be reduced to zero. Experiments showed that fluid temperatures between 20 degrees C and 40 degrees C measured from the surface of a Tygon tube would be accurate within +/- 0.2 degrees C. Response time of ramp-like change in the fluid temperature from 20 degrees C to 30 degrees C was about 3 min. Animal and clinical tests showed this device to be highly accurate.

Adult↗

Low density lipoprotein apheresis during cardiopulmonary bypass of hypercholesterolemic patients.

Ischemia-reperfusion injury in open heart surgery can cause atherosclerotic changes in both bypass grafts and native coronary arteries by increasing endothelial permeability and allowing excessive influx of LDL into the subendothelium. The authors used LDL apheresis during cardiopulmonary bypass (CPB) to actively remove serum LDL before reperfusion, minimizing LDL influx. They evaluated the efficacy and safety of this new procedure in eight hypercholesterolemic patients. The control group consisted of 41 patients. Mean LDL cholesterol (LDL-C) level on admission was 180 +/- 41 (SD) in the LA group and 139 +/- 32 mg/dl in the control group (p = 0.02). After 105 +/- 27 min of apheresis, the LDL-C level in the LA group decreased to 62 +/- 25 mg/dl (reduction rate: 59 +/- 18%). In contrast, in the control group, the LDL-C level was reduced to 117 +/- 41 mg/dl (reduction rate: 16 +/- 9.5% [P = 0.0001]) after CPB. No significant difference was observed in intraoperative blood loss, postoperative blood loss, platelet count, prothrombin time, activated partial thromboplastin time, incidence of wound complications, or early patency rate of bypass graft between groups. Low density lipoprotein apheresis during CPB is a safe and effective method for lowering serum LDL level sufficiently before reperfusion, and can adequately reduce LDL influx into the vessel wall.

Aged↗