Biomedical subjects

M Kawasuji

Publications and source records attributed to M Kawasuji.

At least 37 records · Page 2Linked to original sources

PubMed1998

Myocardial oxygenation during terminal warm blood cardioplegia.

BACKGROUND: Terminal warm blood cardioplegia accelerates myocardial metabolic recovery. The process of myocardial oxygenation during terminal warm blood cardioplegia and its optimal administration are not clear. METHODS: We measured the myocardial tissue oxygen saturation (SO2) during reperfusion using near-infrared spectroscopy. Twenty-four dogs underwent 1 hour of ischemic arrest with cold crystalloid cardioplegia. They were then divided into four equal groups. Group 1 dogs received normal blood reperfusion. The other dogs received 15 mL/kg of terminal warm blood cardioplegia at 80 mm Hg in group 2 or at 60 mm Hg in group 3, and 30 mL/kg of cardioplegia at 60 mm Hg in group 4, followed by blood reperfusion. RESULTS: In group 1, the SO2 increased gradually during the early reperfusion and decreased transiently during the late reperfusion. In group 2, the SO2 increased rapidly but it decreased transiently during blood reperfusion. In groups 3 and 4, the SO2 increased rapidly and remained at high levels during the blood reperfusion. Reperfusion ventricular fibrillation occurred along with a SO2 decrease only in groups 1 and 2. The postischemic troponin-T levels of groups 3 and 4 were lower than that of group 1. The functional recovery in group 4 was better than those in the other three groups. CONCLUSIONS: Terminal warm blood cardioplegia accelerates the early SO2 increase and abolishes the SO2 decrease during subsequent reperfusion and reduces the incidence of reperfusion arrhythmia, suggesting that it ameliorates reperfusion injury and consequently improves postischemic functional recovery.

Animals↗

PubMed1998

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

BACKGROUND: Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. METHODS: An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. RESULTS: In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). CONCLUSIONS: The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

Animals↗

PubMed1998

Prevention of spinal cord ischemia by selective intercostal arterial infusion of prostaglandin E1.

PURPOSE: A new protective method against the spinal cord ischemia that occurs during aortic clamping was investigated in dogs. Oxygenated blood containing prostaglandin E1 (PGE1) was administered at the clamped aortic segment, and the effect was evaluated by measurement of the sensory evoked spinal potential (SESP). METHODS: In 30 dogs, a thoracotomy was made with dissection of the thoracic aorta. After intravenous heparin (100 units/kg) was administered, the proximal and distal descending thoracic aortas were cross-clamped for 60 minutes. Group A (n=10) received oxygenated blood at the rate of 1.0 ml/kg/min. Groups B (n=10) and C (n=10) received oxygenated blood at the same rate, with PGE1 at the dosage of 25 and 50 ng/kg/min, respectively. The infusion was continuously administered throughout the entire period of ischemia. SESP was measured with epidural electrodes before clamping, 10 and 60 minutes after clamping, and 10 and 60 minutes after declamping. Neurologic outcome was assessed at 24 hours after the operation and graded according to the method of Tarlov. RESULTS: There was no significant hemodynamic change in any group. At 60 minutes after damping and at 10 and 60 minutes after declamping, the amplitude of SESP was lower than that at preclamping in groups A and B (p < 0.05). At 60 minutes after damping and at 10 and 60 minutes after declamping, the SESP was more markedly decreased in group A compared with groups B and C. Regarding postoperative neurologic outcome, the dogs with SESP amplitude of more than 50% of the preclamping control value at 60 minutes after clamping showed neither paralysis nor paraplegia. Seven of nine dogs with less than 50% SESP amplitude showed neurogenic deficit. In a comparison of groups A, B, and C, the Tarlov score for group A dogs was significantly lower than that for group C dogs (p < 0.05). CONCLUSION: In this model, PGE1 administration at the rate of 50 ng/kg/min showed sufficient spinal cord protection against ischemia without a decrease in the blood pressure. Further studies are needed to determine the dose that will provide the maximal protective effect and to determine the maximum duration of ischemia against which PGE1 shows protective effects.

Alprostadil↗

PubMed1998

Ultrastructural assessment of the myocardium receiving intermittent antegrade warm blood cardioplegia.

Ultrastructural changes in the myocardium during intermittent warm blood cardioplegia were studied in 12 dogs. During cardiopulmonary bypass, dogs received three 5-minute periods of warm blood cardioplegia, interrupted by three 10-minute episodes of ischemia in group A or three 20-minute episodes of ischemia in group B. Biopsy specimens were taken from the right ventricle before each cardioplegic infusion and at the end of the aortic cross-clamp period to analyze ultrastructural changes. Functional recovery was measured after cardiopulmonary bypass. Mild and principally reversible ultrastructural changes were observed in group A. In group B, moderate ultrastructural changes were observed, and these changes suggested cumulative ischemic injury. Functional recovery was good in group A, but significantly deteriorated in group B. We concluded that three 10-minute interruptions of warm blood cardioplegia cause mild ultrastructural changes and seem to be safe, but three 20-minute interruptions cause cumulative ischemic injury in normal dog hearts.

Animals↗

PubMed1998

[Pitfall of minimally invasive direct coronary artery bypass].

Six thoroughly selected patients underwent minimally invasive direct coronary artery bypass grafting (MIDCAB). While monitoring left ventricular function with transesophageal echocardiography, MIDCAB was done by performing small left thoracotomy through the fourth intercostal space, dissection of the left internal thoracic artery without thoracoscopy, ischemic preconditioning, and grafting of the internal thoracic artery to the left anterior descending coronary artery with 8-0 polypropylene continuous suture. A home-made cardiac stabilizer and Visuflow enabled us to perform precise suturing of the internal thoracic artery. The patency of all grafts was confirmed by early transthoracic Doppler echocardiography and selective angiography. A new stenosis of the coronary artery distal to the anastomosis was detected probably due to coronary snaring in one patient. The anastomosis sites were confined to the distal segments of the left anterior descending coronary artery in MIDCAB patients. The optimal anastomosis site may be missed in the patients with proximal left anterior descending artery disease. An experimental study of myocardial tissue oxygen saturation using near infrared spectroscopy showed that two times of coronary occlusion and reperfusion provided satisfactory effects of ischemic preconditioning. Measurement of the myocardial tissue oxygen saturation may be helpful for confirming effective ischemic preconditioning and a safe coronary occlusion during MIDCAB. Although MIDCAB is an attractive procedure, we should consider the accuracy of anastomosis, the risk of possible incomplete revascularization, the indications, and long-term results.

Aged↗

PubMed1998

[A case report of cavernous hemangioma of the left atrial epicardium].

Cardiac hemangioma is a rare benign vascular tumor. A 44-year-old woman with hemangioma arising from the left atrium and transient atrial fibrillation is reported. Echocardiography, computed tomography and magnetic resonance imaging suggested a hypervascular tumor with clear borders in the pericardial cavity. Selective coronary angiography demonstrated feeding arteries arising from the right and left circumflex coronary arteries. Under cardiopulmonary bypass the tumor was successfully resected. Pathological examination showed a cavernous hemangioma. There is no evidence of recurrence and the patient is doing well three years after the operation.

Adult↗

PubMed1998

[Evaluation of the effect of ischemic preconditioning using near-infrared spectroscopy].

Ischemic preconditioning (IP) protects the myocardium from subsequent sustained ischemic insults. Temporary occlusion of the coronary artery is indispensable for anastomosing the graft vessel during coronary artery bypass operation without cardiopulmonary bypass. In the canine model of ischemia and reperfusion, we measured myocardial tissue oxygen saturation (SO2) continuously using near-infrared spectroscopy to determine the effect of IP on myocardial oxygen metabolism. Nine dogs underwent occlusion of the left descending coronary artery for three 5-minute periods, followed by three 5-minute periods of reperfusion. The dogs were then subjected to a 20-minutes periods of sustained coronary artery occlusion, followed by prolonged reperfusion. The myocardial SO2 was 82 +/- 2% at the baseline before coronary occlusion and was decreased to 74 +/- 2%, 76 +/- 2%, 77 +/- 3%, 77 +/- 3% at the first, second, third and sustained coronary occlusion, respectively. The increase in the minimum myocardial SO2 value at the second and third coronary occlusion suggested the effect of IP. Near-infrared spectroscopy is a useful method of continuously monitoring myocardial oxygenation and of evaluating the effect of IP during off-pump heart surgery.

Animals↗

PubMed1998

Branched graft technique for middle aortic syndrome. Three case reports.

BACKGROUND: Middle aortic syndrome is a rare disease caused by stenosis of the distal thoracic and abdominal aorta involving the visceral and renal arteries. METHODS: We performed reconstructive bypass surgery for three middle aortic syndrome patients. We used magnetic resonance angiography as well as conventional angiography to assess the stenotic vessels. According to these data, branched graft was fabricated preoperatively. We selected Dacron for aortic bypass graft, and ePTFE for the branch graft. In previous reports, branched graft was not applied for the surgery for middle aortic syndrome. RESULTS: Using this branched graft, the clamping time and ischemic time of the organs were shortened. CONCLUSIONS: Using branched graft prefabricated according to accurate preoperative angiographic findings, the reconstructive surgery is thought to proceed more safely.

Adult↗

PubMed1997

Comparison of flow capacities of arterial and venous grafts for coronary artery bypass grafting: evaluation with exercise thallium-201 single-photon emission tomography.

Stress thallium-201 tomography was performed to compare the flow capacities of arterial and saphenous vein grafts in patients with coronary artery bypass grafting (CABG). One hundred and seven consecutive patients (95 male and 12 female; mean age 58+/-9.1 years) underwent exercise-redistribution 201Tl myocardial single-photon emission tomography 4-5 weeks after CABG. When a reversible perfusion defect was present in the area covered by a patent bypass graft, the flow capacity of the graft was defined as insufficient. Of all 285 grafts, 211 were considered as complete bypass. Reversible perfusion defects were present in 29 (27%) of 108 myocardial areas supplied by patent arterial grafts but in only 5 (5%) of 103 myocardial areas supplied by patent saphenous vein grafts (P<0.0001). In the LAD area reversible defects were observed in 22 of 82 areas covered by arterial grafts, in contrast to only 1 of 29 areas covered by venous grafts (P<0.01); in the RCA area reversible defects were observed in 7 of 17 and 4 of 41 areas respectively (P<0.01). There was no difference between the native coronary artery stenosis bypassed by patent arterial and venous grafts (88%+/-12% vs 86%+/-14% respectively, P=0.27). In conclusion, flow capacities during peak myocardial demand were more frequently insufficient in arterial bypass grafts than in saphenous vein grafts.

Coronary Artery Bypass↗

PubMed1997

Failure of gastroepiploic artery graft due to gastroduodenal artery stenosis.

We report a patient with recurrent angina after gastroepiploic artery grafting to the right coronary artery because of a stenotic lesion of the gastroduodenal artery, which limited blood flow through the right gastroepiploic artery graft and caused myocardial ischemia. The patient was successfully treated by saphenous vein grafting to the right coronary artery without cardiopulmonary bypass.

Aged↗

PubMed1997

Near-infrared monitoring of myocardial oxygenation during intermittent warm blood cardioplegia.

OBJECTIVE: This study was performed to examine the ability of near-infrared spectroscopy to monitor tissue oxygenation in the cardioplegically arrested heart and to assess myocardial oxygen metabolism during intermittent warm blood cardioplegia. METHODS: Using a three-wavelength near-infrared spectroscopy, we continuously measured myocardial tissue oxygen saturation and the tissue hemoglobin concentration during intermittent warm blood cardioplegia. Under normothermic cardiopulmonary bypass, 20 dogs received three 5-min periods of antegrade warm blood cardioplegia, interrupted by three 10-min episodes of ischemia in group 1 (n = 7), three 15-min episodes of ischemia in group 2 (n = 6), or three 20-min episodes of ischemia in group 3 (n = 7). RESULTS: Myocardial oxygen saturation during beating and ventricular fibrillation was 80 +/- 1 and 59 +/- 1%, respectively. Myocardial oxygen saturation rapidly increased to 82 +/- 1% at blood cardioplegic infusion and decreased to 58 +/- 1% 3 min after cardioplegic interruption. The time required to reach the peak oxygen saturation level decreased significantly at the second and third infusions compared to the first infusion in group 1, whereas the time increased significantly at the third infusion in groups 2 and 3. The slower rate of increase in oxygen saturation suggested reduced coronary vasodilator reserve due to microvascular abnormalities. Reperfusion ventricular fibrillation occurred in none of group 1, one of group 2 and three of group 3. CONCLUSIONS: Near-infrared spectroscopy is a useful method of continuously monitoring myocardial oxygenation and ischemia during warm heart surgery. Episodes of ischemia longer than 10 min during warm blood cardioplegia resulted in less-than-optimal myocardial preservation and should be avoided.

Analysis of Variance↗

PubMed1997

Hot-knife dissection of the latissimus dorsi muscle for dynamic cardiomyoplasty.

The overall purpose of circulatory assistance utilizing skeletal muscle is the most efficient application of muscle power. From the histological viewpoint, hot-knife dissection of the latissimus dorsi muscle (LDM) is presented to preserve muscle tissue. The shaw hemostatic scalpel could be used similarly to standard surgical blades, and its hemostatic performance was efficient in sealing collateral vessels from the thoracic wall. Muscular and nervous twitching was never observed throughout dissecting the LDM. Histological findings revealed that muscle fibers could be preserved by hot-knife dissection rather than by electrocautery. This technique may reduce the inconvenience of the operators, and, therefore, shorten the operation time in dynamic cardiomyoplasty and other experiments.

Animals↗

PubMed1997

Postoperative influences of surgical cryoablation for Wolff-Parkinson-White syndrome--a analysis of myocardial enzymes and function.

We evaluated postoperative myocardial enzymes and function associated with cryoablation in 20 patients with Wolff-Parkinson-White syndrome undergoing surgical treatment for a single left-sided accessory conduction pathway. Ten patients underwent endocardial atrial incision with cryoablation using CO2 at -60 degrees C for 120 sec (group A), while the remaining 10 patients did not receive cryoablation (group B). Levels of aspartate aminotransferase (GOT), lactate dehydrogenase (LDH), and creatine kinase (CK-MB) on postoperative days 1, 2, and 3 were higher in patients in group A than in group B (p < 0.05). However, mean values remained low (GOT, 120.5 IU/L; LDH, 1105.1 IU/L; CK-MB, 76.3 IU/L). No electrocardiographic changes were detected. Parameters of cardiac function, including cardiac index, stroke volume index, systemic vascular resistance, and ejection fraction, remained unchanged during the postoperative period in both groups. Furthermore, 201Tl cardiac scintigraphy demonstrated no evidence of myocardial perfusion defects due to cryoablation in group A. In conclusion, myocardial damage induced by cryoablation is very minor and is not associated with any clinical impairment of cardiac function.

Adult↗

PubMed1997

[Evaluation of the graft flow reserve after coronary artery bypass grafting by stress 201T1 myocardial SPECT: comparison between arterial grafts and venous grafts].

We performed stress 201T1 myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress 201T1 myocardial SPECT one month after CABG. Each patient's myocardium was divided into 9 segments and visually evaluated using five grade scoring system (0 = defect, 1 = severe decrease, 2 = moderate decrease, 3 = mild decrease, 4 = normal uptake). Eleven of 133 (8.27%) segments covered by patent venous grafts showed reversible 201T1 defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible 201T1 defect. This finding was observed more significantly in arterial grafts than in venous grafts (p < 0.001). These finding suggests that arterial grafts have lower flow capacity than venous grafts at peak exercise.

Aged↗

PubMed1997

[A successful surgical treatment of coronary to pulmonary artery fistula with coronary steal phenomenon due to large volume of shunt: a case report].

A successful surgical treatment of right and left coronary to pulmonary artery fistula was presented. The patient was 61-year-old female, who was admitted for evaluation of cardiac murmur and chest pain. Cardiac catheterization and coronary artery angiogram revealed a large fistula both from RCA and LAD to the main pulmonary artery and distal LAD flow was sealed by this fistula. The left to right shunt ratio was calculated to be 55.1%. Preoperative BMIPP scintigram showed low uptake in the apex of the heart. Operation was indicated, because it was considered that angina pectoris was originated from coronary steal phenomenon. At the operation each right and left coronary shunt flow was measured to be 100 ml/min respectively. The fistulas were ligated and an opening of fistulas draining into the main pulmonary artery was closed through pulmonary arteriotomy under total cardiopulmonary bypass. Postoperative angiogram showed complete disappearance of the fistulas, postoperative BMIPP scintigram became to be normal, and her chest pain disappeared.

Angina Pectoris↗

PubMed1997

Physiological changes during acute obstruction of the superior vena cava, azygos, and internal thoracic veins in dogs.

PURPOSE: In the surgery for superior vena cava (SVC) reconstruction, the cross-clamping of the SVC may cause brain damage. Experimental study was performed to clarify the safe limit of the clamping time and the appropriate monitoring method during the surgery. METHODS: In anesthetized dogs, the internal thoracic and azygos veins were ligated, and the SVC was clamped for 120 min. Arterial blood pressure, intracranial venous pressure, regional cerebral blood flow, and electroencephalogram were monitored in six dogs. Somatosensory evoked potentials were recorded in one other dog, and in another dog postoperative neurological changes were evaluated for 3 weeks. The brains of the dogs were subjected to the histological examination including tetrazolium stain. RESULTS: The arterial blood pressure decreased and the intracranial venous pressure increased during the clamping. Oscillation of the pressure was noted at 45 to 74 min after clamping. The regional cerebral blood flow was 57.4 ml/100 g/min on average before clamping, and decreased to 15.5 ml/100 g/min at 105 min after clamping. The electroencephalogram demonstrated no pronounced change during clamping, but the amplitude of the somatosensory evoked potentials decreased and the latency was prolonged during clamping. No neurological defect was noted in the dog observed for 3 weeks. All areas of the brain showed staining with the tetrazolium, indicating intact mitochondria. The microscopic findings for the brains included no marked changes. CONCLUSION: The SVC clamping for 120 min was tolerated by the dogs, and the most reliable monitoring method was concluded to be the recording of somatosensory evoked potentials.

Animals↗

PubMed1997

Bypass grafting for a right proximal subclavian artery pseudoaneurysm patient using a long temporary bypass.

We report an 80-year-old woman, with pseudoaneurysm of the right proximal subclavian artery despite the absence of a history of trauma. On preoperative examinations, the aneurysm involved to the common carotid arteries. A long temporary bypass using a heparin-coated tube from the right femoral artery to the right common carotid artery was created under low dose systemic heparinization. A Dacron bifurcation graft bypassing was then performed successfully. At surgery for right proximal subclavian artery aneurysm, which often involves the right common carotid artery, intraoperative accident or bleeding can induce brain ischemia. A temporary bypass should be prepared. Although the short temporary bypass from the aorta to the right common carotid artery was reported, this carries the risk of complications due to microemboli. The heparin-coated tube provided excellent anti-thrombosis. Inflow cannulation should be placed at the peripheral artery not the aorta.

Aged↗

PubMed1997

Assessment of improvement of myocardial fatty acid uptake and function after revascularization using iodine-123-BMIPP.

UNLABELLED: We used beta-methyl iodophenyl pentadecanoic acid (BMIPP) to evaluate changes in myocardial fatty acid utilization before and after revascularization and the ability of BMIPP to predict functional recovery in patients with chronic coronary artery disease. METHODS: Thirty-four patients with chronic coronary artery disease (60 +/- 10 yr) underwent BMIPP and 201Tl SPECT (stress-reinjection 201Tl in 29 patients and resting 201Tl in 5 patients) before and 2-5 wk after percutaneous transluminal angioplasty (n = 23) or coronary artery bypass surgery (n = 11). Cardiac function was evaluated by gated blood-pool scintigraphy (n = 26) or two-dimensional echocardiography (n = 8) before and after revascularization. RESULTS: In 32 patients with reduced BMIPP uptake before revascularization, scintigraphic findings with 201Tl improved in 28 patients after revascularization. In these 28 patients, BMIPP uptake improved in 20 patients (71%). Wall motion abnormality was observed in 16 of these 20 patients before revascularization, with 15 showing wall motion improvement after revascularization. In eight patients without improvement of BMIPP uptake, despite 201Tl uptake improvement, wall motion abnormality was observed in four patients before revascularization; after revascularization, one showed wall motion recovery, and three did not. Ejection fraction (EF) improvement after revascularization correlated best with the area of improved BMIPP uptake (r = 0.84, p < 0.0005). EF improvement also correlated with the area of improved reinjection 201Tl uptake (r = 0.54, p < 0.05) and improved 201Tl uptake at stress after revascularization (r = 0.48, p < 0.05). The area of discordant uptake of BMIPP less than reinjection 201Tl uptake before revascularization was a good predictor of EF improvement after revascularization (r = 0.58, p < 0.01); however, the area of reversible 201Tl defect was not (r = 0.34, p = 0.15). CONCLUSION: In patients with chronic coronary artery disease, functional improvement after revascularization is closely related to the recovery of BMIPP uptake. Discordant BMIPP uptake less than reinjection 201Tl uptake is a potential predictor of functional recovery.

Angioplasty, Balloon, Coronary↗