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Biomedical subjects

R Omoto

Publications and source records attributed to R Omoto.

At least 145 records · Page 8Linked to original sources
PubMed1987

Bleeding varices located in the second portion of the duodenum.

A 41-year-old woman with cirrhosis of the liver was admitted to our hospital because of a severe melena. Blood pool scanning with labelled red blood cells showed a high concentration in the right upper quadrant of the abdomen. Endoscopy of the second portion of the duodenum revealed fresh blood on the first examination and varices with overlying erosion were evident in the second study. Co-existent esophageal varices were present but were apparently not associated with the bleeding. Because of the continuous hypotension even with blood replacement, ligation and sclerotherapy were performed. To evaluate the efficacy of the procedures, intraoperative two-dimensional Doppler echography was used and the transducer was applied directly to the viscera. Blood flow was visualized in the serosal and submucosal varices. After ligation and sclerosing of the veins, the blood flow velocity signals disappeared. This woman died of multiple organ failure on the ninth postoperative day.

Adult↗
PubMed1987

Colour flow mapping of oesophagogastric varices and vessels in and around the liver with trans-oesophageal real-time two-dimensional Doppler ultrasound.

Conventional transcutaneous ultrasound examinations are often compromised by intervening intestinal or pulmonary gas and have limited resolution. Ultrasonic probes of frequencies greater than 5 MHz, which enhance resolution, cannot be used successfully on the skin surface, because they do not penetrate enough to to visualise intra-abdominal organs in most adults. To overcome these problems, we have used transoesophageal real-time two-dimensional Doppler echography. The ultrasonic probe, with a 5 MHz, curved array, was integrated into the end of a steerable insertion tube. Fifteen patients with oesophagogastric varices were examined. Oesophagogastric varices were visualised in colour in 10 patients. The direction of blood flow was determined in six patients. The flow velocity was measured quantitatively in five patients by the pulsed Doppler technique. The vessels in and around the liver were also visualised even when they could not be seen with transcutaneous ultrasonography. This technique is useful for the evaluation of both oesophagogastric varices and other abdominal vessels.

Adult↗
PubMed1987

Visualization of distal splenorenal shunt by isotopic splenovenography.

Radioisotopic angiography of the splenic vein was performed in six patients following a distal splenorenal shunt (Warren procedure). Under echographic guidance, the spleen was punctured with a 22-gauge needle, and Tc-99m pertechnetate was injected into the splenic pulp. In five patients whose esophageal varices had remained atrophic, the splenic vein, the left renal vein, the inferior vena cava, and the heart were clearly visualized within 8 seconds. In one patient, in whom recurrence of esophageal varices had been recognized, the splenic vein was not imaged. The injected material coursed mainly upwards through collaterals.

Aged↗
PubMed1987

Visualization of thoracic dissecting aortic aneurysm by transesophageal Doppler color flow mapping.

Real-time color flow mapping by two-dimensional Doppler has now come into widespread use. However, its application via conventional transcutaneous approaches to dissecting aortic aneurysm has some limitations where visualization of the descending aorta is concerned. Its transesophageal approach to this disorder has hitherto remained unreported except by the authors. Transesophageal Doppler color flow mapping has been performed in twelve patients for diagnosis of dissecting aortic aneurysm, and the clinical significance of this method was evaluated. The system used for transesophageal color flow mapping was an Aloka SSD-880 ultrasound scanner with a 5 MHz probe. In all cases, the entire thoracic aorta except for the upper ascending aorta was visualized and both, real-time flow dynamics and structural information, were ascertained. Differentiation of the type of dissection, identification of the entry, and differentiation of the true and false lumina were performed in all cases. Information concerning the reentry was gained in seven cases (58%); aortic regurgitation was graded in three cases, in two of which prolapse of the intimal flap was observed. In five cases, aortography was needed in order to delineate the involvement of aortic branches in the dissection; and in the other seven cases, transesophageal Doppler information was sufficient. In four cases who were operated, the postoperative state was well evaluated. Transesophageal Doppler color flow mapping was found to be a useful method for visualization of the whole thoracic aorta apart from the upper ascending section, and for precise evaluation of the structure and hemodynamics of dissecting aortic aneurysms.

Aortic Dissection↗
PubMed1987

Immediate and early postoperative evaluation of results of cardiac surgery by transesophageal two-dimensional Doppler echocardiography.

In cardiac surgery significant residual lesions increase postoperative morbidity and mortality. Although intraoperative epicardial real-time two-dimensional Doppler echocardiography (two-dimensional Doppler) is an accurate and efficient technique for assessing the presence and severity of a residual lesion, it requires placement of a transducer in the operating field and consequent obstruction of the operative procedure. Transesophageal two-dimensional Doppler echocardiography (transesophageal two-dimensional Doppler), which can be applied intraoperatively and postoperatively without such problems, was performed in 35 patients during cardiac surgery (12 patients) and/or at an intensive care unit within 6 hr after cardiac surgery (30 patients). In those with constrictive pericarditis, an extensive pericardiectomy was performed with effective monitoring by intraoperative transesophageal two-dimensional Doppler. Abnormal posterior wall motion was observed in the case of left ventricular rupture (type III) after mitral valve replacement 3 hr before clinical manifestation. After prosthetic valve replacement (18 St. Jude Medical valves, one Carpentier-Edwards valve, one Björk-Shiley valve), no perivalvular leakage was detected, but minor physiologic transvalvular leakage was noticed in 11 patients with St. Jude Medical valves. In two patients with congenital heart disease, a small residual shunt was detected. In a patient in which a composite valve graft with direct coronary artery reattachment (Bentall's operation) was performed, reattachment was confirmed to be satisfactory. In conclusion, intraoperative and early postoperative monitoring of cardiac function by transesophageal two-dimensional Doppler echocardiography can improve the results of cardiovascular surgery by providing accurate information on cardiovascular structure and blood flow dynamics.

Adult↗
PubMed1986

Doppler ultrasound examination of prosthetic function and ventricular blood flow after mitral valve replacement.

Two-dimensional color Doppler echocardiography enables delineation of the spatial and temporal distribution of blood flow in the heart. In this study, the method was applied for investigation of flow dynamics in multiple planes in the region of prosthetic mitral valves for comparison with that of native mitral valves. In 15 healthy subjects there was normal flow toward the transducer, coded in red, in the left ventricle along the posterolateral wall (left ventricular inflow region) and blue-coded flow away from the transducer in the left ventricular outflow region during diastole. In 40 patients with St. Jude mitral valve prosthesis and 17 with bioprosthesis the flow pattern in the left ventricle was reversed. Mitral inflow was directed against the interventricular septum, accordingly, into the left ventricular outflow region while the outflow pattern was displaced posterolaterally into the left ventricular inflow region during diastole. The angle between the aortic valve ring and the mitral annulus was significantly smaller than in the healthy subjects. The angle between the central axis of the mitral prosthesis and the mitral inflow, which was 0 degrees in healthy subjects, was increased by the medial deviation in particular, in those with mechanical St. Jude prostheses. The maximal transprosthetic velocity, measured in 70 patients, and the maximal pressure gradient calculated according to the Bernoulli equation was substantially greater than the values in healthy subjects. In contrast to findings associated with normally-functioning prostheses, in four patients with prosthetic malfunction there was a diastolic peak velocity of more than 2 m/s as well as marked turbulence in the inflow region.

Bioprosthesis↗
PubMed1986

[Immediate surgical revascularization following unsuccessful coronary thrombolysis: effects on myocardial salvage].

To reduce early and late mortality and morbidity following acute myocardial infarction (AMI), myocardial salvage of the jeopardized areas by coronary thrombolysis (PTCR) during the acute period is effective. However, unsuccessful thrombolysis or severe residual coronary stenosis may result in severe cardiac failure and high mortality in the early and late periods. This study was undertaken to demonstrate the effects of immediate coronary artery bypass surgery (CAB) following unsuccessful PTCR. Thirty-three patients with initial AMI were studied, in whom PTCR was performed within 10 hours of onset of chest pain but it was unsuccessful. In 16 cases (Group I) total occlusion could not be recanalized, and in 17 cases (Group II) subtotal residual stenosis (99% with delayed flow on coronary angiogram) remained. The effects of immediate CAB surgery (Group I-b: 4 cases; Group II-b: 9 cases) for myocardial salvage were evaluated by thallium-201 scintigraphy one to 14 months after onset of AMI, as compared to medical therapy (Group I-a: 12 cases; Group II-a: 8 cases). The thallium uptake in the jeopardized area was categorized as (1) defect (+), (2) decrease, and (3) defect (-). All 12 cases in Group I-a showed defect (+). In Group I-b, one case showed defect (+), one case decreased, and two cases defect (-). In Group II-a, seven of eight cases (88%) showed defect (+) and one case showed decrease; however, in Group II-b seven of nine cases (78%) showed defect (-) and two cases showed defect (+). The effects on myocardial salvage were significantly different between Group a and Group b (p less than 0.001) and Group II-a and Group II-b (p less than 0.01). In conclusion, immediate CAB surgery was superior to medical therapy for ischemic myocardial salvage following unsuccessful PTCR. These results encourage the application of immediate postinfarction CAB surgery in high-risk groups with severe residual coronary stenosis after PTCR.

Aged↗
PubMed1986

[Radionuclide angiography (scintiphotosplenovenography) in the evaluation of splenorenal shunt patency].

Radionuclide angiography of the splenic vein (Scintiphotosplenovenography: SSV) was done in 7 patients following a distal splenorenal shunt (Warren procedure). Spleen was punctured with a 22 gauge needle under ultrasonographic guidance. One half ml of 99m TcO4- solution, which contained 10 mci of nuclide energy, was injected into the splenic parenchyma through the needle. Injected material was followed by scintillation camera. In five cases, whose esophageal varices had been endoscopically atrophic, the splenic vein, the left renal vein, the inferior vena cava and the heart were clearly viewed in a continuity within 8 seconds from the start of injection. In one case, whose varices had recurred soon after the operation, only the collaterals were delineated. Most of them seemed running upwards alongside the esophagus. In the remaining patient, whose varices had been atrophic, the splenic vein was faintly delineated within 8 seconds. However, most of the 99m TcO4- stayed at first in the spleen. Thereafter it went out into the collaterals, the lower intercostal vein and the hemiazygos vein. This method is less invasive than the conventional angiography. It can reveal not only the entire imaging of shunt flow but also the collaterals, if they exist. It seemed useful for the evaluation of shunt patency following distal splenorenal shunt.

Female↗
PubMed1986

[Visualization of coronary blood flow by transesophageal Doppler color flow mapping].

For noninvasive evaluation of coronary blood flow, 22 patients were examined with transesophageal Doppler color flow mapping within six hours after cardiovascular surgery. The anatomical structure of the left main coronary trunk (LMT) was observed by conventional two-dimensional echocardiography (2-DE) in 20 patients (91%), and color flow of the LMT was visualized in 18 of 21 patients (86%) (one patient had total occlusion). The blood flow in the LMT began in mid-systole, but the flow was observed mainly in diastole. The peak of the flow was observed mainly in late diastole and the range of the peak velocity was 35 to 163 cm/sec (average = 76.9 +/- 31.4 cm/sec). The proximal portion of the right coronary artery (RCA) was observed in 13 patients (59%), and its color flow was visualized in only two patients (9%). In two patients intra-aortic balloon pumping (IABP) assist was performed postoperatively, and the direct effect of the assist on the coronary blood flow was clearly observed by transesophageal Doppler color flow mapping. The peak blood flow velocity of the LMT increased by 32% during the assist. In conclusion, human coronary blood flow can be visualized and evaluated noninvasively using transesophageal Doppler color flow mapping. This technique can be used for future investigation of coronary circulation.

Adult↗
PubMed1985

Systemic dissemination of ethanolamine oleate after injection sclerotherapy for esophageal varices.

Sclerotherapy for esophageal varices was performed on six patients for a total of 16 injections. The sclerosant contained 5% ethanolamine oleate and technetium Tc 99m sodium pertechnetate solution at the volume ratio of 9:1. At each injection session 5 to 20 mL of this solution was injected into one varix. The distribution of the injected material was observed by a scintillation camera. Systemic dissemination of the sclerosant through the portal vein was demonstrated in five procedures, in which the injections were correctly intravenous. In three dogs 4 mL of 5% ethanolamine oleate made from oleic acids labeled with iodine 131 was injected into the gastric coronary vein. Most of the substance injected was washed out within five minutes, and systemic dissemination became evident.

Adult↗