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Biomedical subjects

R Matsuwaka

Publications and source records attributed to R Matsuwaka.

At least 37 records · Page 2Linked to original sources
PubMed1992

Assessment of regional and transmural myocardial perfusion by means of intraoperative myocardial contrast echocardiography during coronary artery bypass grafting.

By using intraoperative myocardial contrast echocardiography, we assessed regional myocardial perfusion and transmural blood flow distribution immediately after myocardial revascularization. A total of 62 revascularized myocardial areas were studied in 31 patients undergoing coronary artery bypass grafting. The revascularized areas were divided into three different areas: S area, supplied by significantly stenosed coronary arteries (43 areas); C area, supplied by coronary collateral situation associated with totally occluded coronary arteries (12 areas); MI area, preexisting transmural myocardial infarction (7 areas). Myocardial contrast echocardiography was obtained by direct injection of 2 ml of sonicated 5% human albumin into the saphenous vein grafts at rest and during atrial pacing. Each area was divided into two layers of endocardial and epicardial halves, and myocardial enhancement of peak intensity was measured for each half and endocardial/epicardial gray level ratio was calculated: (1) The peak intensity of myocardial enhancement in S area and C area was significantly higher than that in MI area at rest as well as during pacing after myocardial revascularization. There was no significant difference in the peak intensity between S area and C area both at rest and during pacing. In S area the peak intensity significantly increased during pacing (p < 0.01), whereas it did not change in C area and MI area. (2) S area demonstrated no significant change in endocardial/epicardial intensity ratio during pacing. In contrast, the ratio in C area significantly decreased during pacing. (3) In S area with preoperative percent increase of segmental wall thickening lower than 25%, there was a significant correlation (r = 0.84, p < 0.001) between the peak intensity of myocardial enhancement and the postoperative changes of percent increase of segmental wall thickening in the revascularized areas. Thus, immediately after myocardial revascularization, intraoperative myocardial contrast echocardiography could provide a quantitative assessment of regional myocardial perfusion as well as blood flow distribution in the areas with myocardial infarction and with coronary collateral situation and in the areas supplied by stenosed coronary arteries.

Cardiac Pacing, Artificial↗
PubMed1992

[Assessment of the size and distribution of the coronary artery selected for bypass grafting using myocardial contrast echocardiography during coronary artery bypass surgery].

We assessed the size and distribution of the native coronary artery selected for bypass grafting, using myocardial contrast echocardiography by injection of sonicated agents into a saphenous vein graft, during surgical revascularization. A total of 69 saphenous vein grafts (LAD, 16; D1, 10; OM, 13; PL, 13; RCA, 17) were performed in 36 patients with right dominant system at preoperative coronary angiogram. The size of the area of revascularized myocardium was quantified with the ratio of its circumference to a full circle depicted on the left ventricular short-axis view at the mid-papillary level. The extents of the revascularized area to LAD stenosing at the proximal portion was 28 +/- 6% and stenosing at the intermediate portion was 23 +/- 6%. D1, 10 +/- 2%; OM, 17 +/- 3%; PL, 22 +/- 6%, RCA, 17 +/- 5%. The extent of the areas perfused by the totally occluded coronary arteries with collateral vessels was similar to those perfused by the partially occluded coronary arteries. In conclusion, myocardial contrast echocardiography enabled the intraoperative assessment of the geometry of regional myocardial perfusion, and was very useful for the intraoperative evaluation of the effectiveness of the indicated surgical procedure.

Arteries↗
PubMed1992

[Open heart surgery without homologous blood transfusion in small children of body weight less than 20 kg].

In 28 children with congenital cardiac lesions, open heart surgery was attempted without homologous blood transfusion using extreme hemodilution for cardiopulmonary bypass (CPB) and moderate to profound hypothermia. The entry criteria for this study were preoperative hemoglobin value above 10 g/dl and expected CPB time of less than 120 minutes. Acyanotic heart diseases such as ventricular or atrial septal defect were the main lesion, but some cases of tetralogy of Fallot and single ventricle were also included in this study. Intraoperative saving of autologous blood and autotransfusion using cell saver were carried out in a part of the subjects. Acceptable lowest values for hemoglobin was 4-5 g/dl and 40% for mixed venous oxygen saturation. As the results, 18 patients tolerated CPB without transfusion and eventually 16 patients were discharged without transfusion at all. The body weight for those without transfusion was 13.9 kg in average and the lowest was 6.8 kg. The significant factor affecting the needs for homologous blood transfusion was prolonged CPB time over 120 minutes. Although there was a tendency that the patients with body weight less than 15 kg received transfusion more frequently than those with body weight more than 15 kg, the body weight was not necessarily a limiting factor. Pre-CPB blood saving and intraoperative autotransfusion were the positive factors for successful non-transfusion open heart surgery.

Blood Transfusion↗
PubMed1991

Evaluation of a new finger-type intraoperative epicardial echocardiographic probe for infants and small children.

A new finger-type epicardial echocardiographic probe was evaluated in 26 children with complex cardiac anomalies during open heart surgery. The probe is a small 3.75 MHz phased array transducer for 2-dimensional echo and color Doppler imaging. The tip is slightly angled to facilitate the apical approach through a median sternotomy. The patients included 4 neonates and 8 infants, and the major cardiac lesions were complete atrioventricular (AV) canal, transposition of the great arteries, double outlet right ventricle, and others. The intraoperative study was possible in most of the patients facilitating various approaches for the assessment of left-sided AV valve function, left ventricular outflow obstruction, residual shunt and intraatrial anatomy. Four patients received subsequent operative procedures after the assessment. This transducer appears to be useful in the intraoperative study during surgery for complex cardiac anomalies in neonates and small infants.

Child↗
PubMed1991

A new angled transducer for intraoperative epicardial echocardiography.

We tested a new angled transducer developed for intraoperative epicardial echocardiography in 42 patients. This small transducer, 70 x 20 x 15 mm in size, demonstrated superior operability and provided adequate two- or four-chamber imaging from the apical approach, which may lead to high-quality assessment with two-dimensional Doppler flow imaging.

Adolescent↗
PubMed1991

Hepatic venous oxygen saturation monitoring in patients with assisted circulation for severe cardiac failure.

In order to assess the adequacy of hepatic perfusion, hepatic venous oxygen saturation (ShvO2) was monitored in five patients undergoing mechanical circulatory support. Two patients were with intra-aortic balloon pumping (IABP), one was with a left ventricular assist device (LVAD), and two were with biventricular assist devices (BVAD). The mean ShvO2 values during assistance in each patient ranged from 27 to 84%. One patient with IABP showed persistently low ShvO2 (less than 30%) in spite of higher mixed venous oxygen saturation (SvO2) and subsequently developed hepatic dysfunction and multiple organ failure. In another patient, ShvO2 was 22% on average during LVAD, but increased to greater than 50% after adding a right ventricular assist device (RVAD). Of 3 patients with persistently high ShvO2 (44-80%, on average), only one developed hepatic failure--probably from prior severe shock--and the other two did not develop hepatic failure. There was a significant negative correlation between ShvO2 and splanchnic excess lactate, the parameter of anaerobic metabolism in the splanchnic area. In contrast, there was no correlation between simultaneously measured ShvO2 and SvO2 values when analyzed in a range of SvO2 below 70%. ShvO2 monitoring may be useful for evaluation of hepatic perfusion status in the management of critical patients, requiring assisted circulation.

Heart Failure↗
PubMed1991

[Biventricular assist support using centrifugal pump in cardiogenic shock following coronary bypass grafting--a case report of long survival].

Biventricular assist support (BVAS) with centrifugal pump was used for the treatment of 48 y/o male patient with cardiogenic shock following coronary bypass surgery. Assist flow was 2 to 4 l/min in LVAS and 2 to 3 l/min in RVAS. RVAS was weaned in the fourth postoperative day and LVAS in the sixth. Cerebral infarction developed in the weaning period of LVAS. Post operative examination revealed good right and left ventricular function. Patient was well and returned to full work in a two years and two months after surgery. BVAS may be useful for the treatment of severe biventricular failure associated with stunned myocardium.

Adult↗
PubMed1991

Long-term survival and complications after composite graft replacement for ascending aortic aneurysm associated with aortic regurgitation.

The Bentall operation was performed in 44 patients between March 1972 and December 1988. Twenty patients had stigmata of Marfan's syndrome, and 15 had aortic dissection. All showed annuloaortic ectasia. Follow-up ranged from 1 to 16 years (mean, 5.8 years). There were six early deaths (14%) and seven late deaths (16%), with actuarial survival at 10 years of 65 +/- 8%. The late deaths were mostly related to aneurysms occurring in the remainder of the aorta. No patient has undergone reoperation related to the composite graft, but six patients required seven subsequent operations on the remaining aorta. The actuarial probability of freedom from late death and subsequent operation at 8 years was 64 +/- 9% for the operative survivors, but it was 44 +/- 17% for the patients with aortic dissection and 37 +/- 19% for those with Marfan's syndrome. Postoperative angiography performed 3-168 months (mean, 42 months) postoperatively in 23 nonselective patients demonstrated recurrent true aneurysms at both or one of the coronary ostia (seven), persistent dissection distal to the distal aortic anastomosis (five), pseudoaneurysm at the left coronary ostium (one), pseudoaneurysm due to a small leak at the proximal aortic anastomosis (one), and partial dehiscence of the distal aortic suture line (one). Composite graft replacement carries a potential risk of various late complications. Our data support the concept that earlier detection and aggressive treatment of the late complications occurring in the remainder of the diseased aorta is necessary to improve long-term survival after the Bentall operation.

Actuarial Analysis↗
PubMed1991

[Recent progress and future prospect of the prolonged extracorporeal lung assist for respiratory failure].

Extracorporeal membrane oxygenation (ECMO) is becoming an accepted therapeutic option for acute respiratory failure in both infants and adults. ECMO has been applied for relatively short-term support and numerous centers have reported satisfactory results with emphasis on patient selection, techniques of cannulation and perfusion, and prevention of complications. To use ECMO for a prolonged support, however, new type of artificial lung and system need to be developed. Most of the membrane oxygenators have the possibility of serum leakage through micropores. To prevent this problem, several dense membrane oxygenators have been developed and clinically used with good gas exchange. A low heparin dosage during ECMO results in reduced bleeding complication. Full systemic heparinization can be avoided during ECMO by using heparin-coated perfusion equipment. Respiratory support by means of pumpless PA-LA extracorporeal membrane oxygenation driven by pulmonary arterial pressure is attractive because of its simplicity and might be suitable for prolonged use. Further studies are necessary to develop an oxygenator for long-term ECMO.

Extracorporeal Membrane Oxygenation↗
PubMed1991

[Bloodless open heart surgery using membrane oxygenator--the efficacy of ultrafiltration].

The efficacy of ultrafiltration (UF) in the attempt of total bloodless open heart surgery using membrane oxygenator (MO) was investigated in two groups. Group I (GI) consisted of 6 ASD operations between Dec. 1983 and Feb. 1987, which cardiopulmonary bypass (CPB) were performed without UF and with non-hemic priming of Capiox II MO. (Age; 18 +/- 2 (SD) years old, Body Weight; 53 +/- 6 kg, CPB; 77 +/- 24 min.) Group II (GII) consisted of 11 cases (4ASD, 1VSD, 4MS/MR (2MVR), 2AR (2AVR] between Mar. 1987 and Sep. 1988, which CPB were performed with UF in 9 cases and with non-hemic priming of CML/VPCML MO. (Age; 34 +/- 20 yo, Body Weight; 52 +/- 12 kg, CPB; 112 +/- 54 min). Total bloodless surgery were successful in 9 cases (82%) of GII against in only one case (17%) of GI (p less than 0.05). The hematocrit values of successful 9 cases in GII were 40 +/- 2% before operations, more than 19 +/- 3% during CPB, 33 +/- 4% just after operations, and more than 29 +/- 3% through the postoperative course. Blood loss during operations were 1013 +/- 586 ml in GI, and 659 +/- 388 ml in GII (NS). Blood loss after operations were 696 +/- 283 ml in GI and 478 +/- 284 ml in GII (NS). In successful 9 cases of GII, blood loss after operations were 387 +/- 215 ml, significantly less than that in GI (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

The effect of left ventricular bypass on the right ventricular function: experimental analysis of the effects of ischemic injuries to the right ventricular free wall and interventricular septum.

The right ventricular (RV) function during left heart bypass (LHB) was examined in open-chest anesthetized mongrel dogs (average weight, 11.8 kg). The LHB was carried out by a left ventricle (LV) to femoral artery bypass using a centrifugal pump for 90 min, and the bypass flow was kept maximum to obtain almost complete decompression of the LV. The RV function was evaluated by hemodynamic parameters and pressure-dimension (sonomicrometry) relationship at pre-LHB (control) and 30, 60, and 90 min after LHB (LHB-30, LHB-60, and LHB-90). The materials were divided into three groups after LHB-30: intact heart (group 1, n = 5), RV free wall ischemia (group 2, n = 5), and interventricular septum (IVS) ischemia group (group 3, n = 8). No significant changes in mean right atrial pressure (mRAP), RV end-diastolic pressure (RVEDP), RV maximum derivative pressure, or RV fractional shortening (RVFS) were found between pre-LHB and post-LHB in groups 1 and 2. On the contrary, group 3 showed significant increases in mRAP and RVEDP, and a decrease in RVFS at LHB-90 compared to both pre-LHB and LHB-30. The RV end-systolic dimension (percentage of pre-LHB) showed significant increases at LHB-90 compared to LHB-30 in groups 2 and 3. These results indicate that the LHB itself does not depress the RV function in the intact heart and in the RV free wall ischemic heart, while the impairment of the IVS during LHB appears to lead to RV dysfunction.

Animals↗
PubMed1990

Analysis of clinical factors for survival after left and biventricular bypass using centrifugal pump following open heart surgery in infants and adults.

A total of eight patients, including three infants, received left or biventricular assist using centrifugal pump (CFP) following open heart surgery. Three infants, aged 9-11 months and with complex cardiac lesions, were supported by left heart bypass (LHB) using pediatric type CFP for 63 h, 64 h, and 13 days. All were weaned from LHB, but long-term survival was not obtained, mainly due to complications. In five adult patients, LHB alone was used in three, and biventricular support in two for 33-240 h with three survivals. The factors related to unsuccessful recovery were delayed start of support and multiorgan failure.

Adult↗
PubMed1990

[Clinical experience of mechanical ventricular support with centrifugal pump for severe ventricular failure after open heart surgery].

Five adult patients (pts) with age 15-67 (mean 43) received mechanical circulatory support with centrifugal pump (Biomedicus, BP-80, Sarns centrifugal pump) for postcardiotomy profound shock. Three pts underwent left ventricular support (LVS) alone, and the other 2 required biventricular support (BVS). Duration of the LVS ranged from 33 to 240 hours (mean 126 hours) and the right ventricular support 92, 120 hrs. Pump flow rate was 1.1 to 2.5 (mean 1.9) L/min/m2. Sixteen pumps were used and the pump exchange was performed 9 times in five pts and an average perfusion time per pump was 57 hrs. Two of 3 pts with LVS alone survived and one died of multiorgan failure associated with right heart dysfunction. In two pts with BVS, one survived and the other died of persistent low cardiac output early after pump removal. As the complication during mechanical support, bleeding was seen in 3 pts and cerebral infarction in one. Although centrifugal pump has potential limitation in antithrombogenicity and durability, this device provides a simple and effective mechanical circulatory support.

Adolescent↗
PubMed1990

[A case of extended myocardial infarction treated with the left ventricular assist device (LVAD) before and after the operation--the value and limitation of LVAD].

A left ventricular assist device (LVAD) was applied to a patient who had profound left ventricular failure following extended myocardial infarction caused by the left main trunk obstruction. The patient was a 61-year-old man, who had severe chest distress and was admitted 11 hours after the onset of the symptom. At the time of admission, he was already in cardiogenic shock. The emergent coronary angiography showed complete obstruction of the left main trunk and the intact right coronary artery which had no collateral flow to the left coronary artery. The intraaortic balloon pumping (IABP) was started bu could not maintain the satisfied circulation. Then a LVAD was applied to the patient 5 days after the onset. The LVAD maintained the normal circulation and prohibited exaspiration of organ failure. 19 days after the onset, scartectomy and A-C bypass to LAD was performed. The patient could not be weaned from LVAD and died of right ventricular failure following ventricular arrhythmia 20 days after the installation of LVAD. The use of LVAD for nonoperative cardiogenic shock is rare. Circulatory support with a LVAD in the treatment of a patient in cardiogenic shock following a acute myocardial infarction was considered useful.

Coronary Artery Bypass↗