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Biomedical subjects

S Kyo

Publications and source records attributed to S Kyo.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Advantages of transesophageal color Doppler echocardiography in the diagnosis and surgical treatment of cardiac masses].

To determine the clinical advantages of transesophageal color Doppler echocardiography (TEE) for imaging cardiac tumors and left atrial thrombi, 24 cases with intra- or extracardiac masses were examined by transthoracic color Doppler echocardiography (TTE) and TEE before and after cardiac surgery. Five with left atrial myxomas, two with lung tumors, five with mediastinal tumors and 12 with mitral stenosis coexisting left atrial thrombi were included in this study. The echocardiographic findings of the cardiac masses were compared with the surgical findings in all cases. In all of the five cases with left atrial myxomas, the tumors were detected. However, the sites of attachment and a stalk in three cases were not observed by TTE. TEE clearly imaged the left atrial myxomas, and evaluated the size and shape of the tumors, the sites of their attachment and a stalk arising from the interatrial septum, and mobility in four cases, except for one in which there was a broad attachment to the endocardium. Mitral regurgitation was detected in only two cases using the color Doppler mode of TTE, but in all cases using TEE. Both techniques failed to recognize tissue characterization. Among seven cases with secondary cardiac tumors or mediastinal tumors, extracardiac masses were detected in five; however, an intracardiac tumor attached to the interatrial septum and an extracardiac tumor extending to the superior vena cava and an upper part of the right atrium could not be imaged using TTE. TEE detected all tumors at all sites in the heart and vessels, and estimates of their extents were in accord with the operative findings in 17 of 18 sites. One exceptional case had a tumor which extended to the right ventricle. Neither technique could detect infiltration of the heart which was present in five of the seven cases. Multiple left atrial thrombi were observed in eight of 12 cases, resulting in 21 thrombi and they were diagnosed by TEE in six of 12 cases. Thrombi, when attached to the left atrial posterior or inferior walls, were easily detected in four of five cases, but were not identified in four of six and in eight of nine cases at the lateral wall or in the left atrial appendage by TTE. However, TEE detected all thrombi in every site in the left atrium and left atrial appendage in 11 of 12 cases. TEE was thus superior to TTE in detecting cardiac masses, recognizing abnormal flow and estimating anatomical relationship between tumors or thrombi and cardiac structures.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Early diagnosis and surgical intervention of acute aortic dissection by transesophageal color flow mapping.

To determine whether transesophageal color Doppler echocardiography (TEE) is useful for the early diagnosis and surgical intervention in acute aortic dissection, 57 serial patients with acute aortic dissection were examined. These patients were evaluated by TEE with either the single-plane probe (39 patients) or the biplanar probe (18 patients) just after admission. The intimal flap was detected in all patients, and there were 18 patients with type A dissection and 39 patients with type B dissection. The entry was visualized in 83% of type A dissection cases and in 90% of type B dissection cases. In two of 18 patients examined with the biplanar probe technique, the entry was detected in the longitudinal view only. Emergency operations were performed in 18 patients with type A dissection and in 10 patients with ruptured type B dissection. Twenty-nine of 39 patients with type B dissection were treated conservatively. The operative mortality rate of patients with type A dissection was 22%, and that of patients with ruptured type B dissection was 60%. The major advantage of TEE is its ease of application at the bedside or in the operating room, which allows immediate and accurate diagnosis of acute aortic dissection for emergency surgical intervention. Biplanar TEE provides additional acoustic windows, ease of spatial orientation, and more accurate visualization of entry. TEE is a useful and powerful diagnostic tool for acute aortic dissection, and by using this method, one may achieve a more rapid and aggressive surgical approach for patients with acute aortic dissection.

Acute Disease↗
PubMed1989

[Responses of aortocoronary bypass graft flow to nitroglycerin, nifedipine and exercise test: a two-dimensional color Doppler echocardiographic study].

To assess the effects of coronary vasodilators and exercise on the blood flow dynamics of aortocoronary bypass grafts (ACBG), two-dimensional Doppler echocardiography was performed in 43 consecutive patients with ACBG of the left coronary artery. Doppler velocity signals of 14 internal mammary artery grafts (IMAG) and three saphenous vein grafts (SVG) were imaged in 15 patients using 5MHZ and 7.5MHZ convex-linear Doppler flow probes. Cross-sectional blood flow velocities and graft internal dimensions were continuously measured before and after the sublingual administration of nitroglycerin (0.3 mg) and nifedipine (20 mg), during isometric handgrip and bicycle ergometer exercise tests. 1. Regurgitant flow in isometric contraction time to early systole was observed in 14 of the 15 patients. Pulsatile diastolic blood flow with mean velocity of 14 +/- 6 cm/sec and volume of 49 +/- 25 ml/min was significantly higher than those in systole (7 +/- 7 cm/sec and 8 +/- 7 ml/min) as observed in IMAG and SVG. IMAG showed smaller vessel dimensions, higher flow velocities and lower flow volumes compared with those of SVG. 2. Nitroglycerin and nifedipine increased blood flow volumes (75 +/- 12%, 79 +/- 11%) and velocities (29 +/- 8%, 28 +/- 8%) due to dilatation of graft vessels (18 +/- 3%, 19 +/- 3%). Nifedipine, in contrast to nitroglycerin, induced sustained increases in graft flows. 3. Isometric handgrip and ergometer bicycle exercise tests increased blood flow volumes (34 +/- 9%, 61 +/- 14%) and velocities (31 +/- 11%, 42 +/- 12%) with elevation of double products (22 +/- 14%, 37 +/- 26%). Ergometer bicycle exercise induced similar responses in systole and diastole, whereas isometric handgrip test induced higher ratios of graft flow volume in systole (67 +/- 25%) compared to those in diastole (28 +/- 9%). In conclusion, two-dimensional color Doppler echocardiography is a promising means for the quantitative analysis of blood flow dynamics, assessments of the variable effects of coronary vasodilators and the physiological responses to exercise tests for the aortocoronary bypass graft flow in the early postoperative state.

Aged↗
PubMed1989

[Visualization of internal mammary artery bypass graft flow using a linear color flow mapping system with a convex type transducer].

To evaluate noninvasively the patency of aortocoronary bypass grafts using the left internal mammary artery (LIMAG), color flow mapping Doppler echocardiography was performed in 23 consecutive patients. There were 22 males and one female. The average number of involved coronary arteries per patient was 2.5 +/- 0.6. The average number of bypassed graft anastomoses was 2.7 +/- 0.9, including 22 isolated LIMAG and one sequential LIMAG. The color flow mapping system used was a linear type 2-D Doppler system (Aloka SSD350) with a convex type transducer. Clear color flow visualization of LIMAG flow was obtained in nine of the 23 patients (39%) studied, with an average peak diastolic velocity of 22.5 +/- 8.7 cm/sec and an average systolic peak velocity of 12.6 +/- 5.7 cm/sec. The coronary angiograms of eight patients were obtained within two weeks after the echocardiographic examinations which demonstrated good graft patency in all LIMAG. Color flow visualization of LIMAG was obtained in four of the eight patients (50%). Although the detection rate was limited, LIMAG flow could be clearly visualized in nearly half the cases studied with stable reproducibility from the transcutaneous echo window. Thus, this technique can be a useful diagnostic means for long-term follow-up of LIMAG and for investigating coronary circulation in the future.

Aged↗
PubMed1987

Myocardial temperature variation: effect on regional function and coronary flow in dogs.

Incremental changes in the temperature (28-42.5 degrees C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 degrees C) circumflex-supplied myocardium. Fast thermistors (time constant less than 0.25 s) continuously monitored midmyocardial temperature in both areas. A Silastic loop with heat exchanger, thermistors, strain gauge, and flow probe was inserted into the LAD and allowed precise control of regional myocardial temperature. Nine-micron microspheres injected into left atrium were used to evaluate coronary flow and distribution. In six anesthetized dogs, relative to normothermic control (38 degrees C), regional systolic shortening decreased 42.2 +/- 10% at 41 degrees C and increased 23.3 +/- 6% at 31 degrees C. There was no significant change in coronary blood flow or distribution at the three temperatures. Pressure-length areas varied inversely with myocardial temperature. These data demonstrate that there is a reversible inverse relationship between midwall T and ventricular function when heart rate, preload, and after-load are controlled.

Animals↗
PubMed1987

[Color flow mapping 2-D Doppler in determining surgical indication for congenital heart disease].

Real-time two-dimensional Doppler echocardiography (2-D Doppler) is established as an effective diagnostic tool for cardiovascular diseases. However, in determining indications for surgery of congenital heart disease (CHD), the possibility of avoiding preoperative cardiac catheterization including radiographic angiography, has not been fully discussed since the clinical introduction of 2-D Doppler. We evaluated 278 patients with CHD by 2-D Doppler including ASDs (75 patients), VSD (76 patients), TOF (23 patients), TGA (12 patients), PDA (23 patients), ECD (13 patients), and 60 miscellaneous types of CHD during 27 months. The diagnosis of the 278 patients were confirmed by catheterization and/or surgery. Of these, 114 patients underwent corrective surgery (83 patients) or palliative procedures (31 patients). Preoperative cardiac catheterization was performed for 88 patients (Group A), and omitted in 26 patients (Group B). The 2-D Doppler diagnosis was correct in 79 patients of Group A (89.8%) and in 26 patients of Group B (100%). The surgical procedures scheduled according to the preoperative 2-D Doppler diagnosis were performed for these 105 patients (92.7%) without any corrections by cardiac catheterization diagnosis or by surgical findings. However, 2-D Doppler failed to establish the preoperative diagnosis for six patients in Group A (two patients with ASD, three with PDA, and one with TOF) and failed to detect associated cardiac abnormalities for three patients in Group A (two with PAPVC, one with Azygos connection). Results of this study suggest that preoperative cardiac catheterization could be omitted in a maximum of about 90% of surgical candidates with CHD. However, to omit cardiac catheterization 2-D Doppler echocardiographic criteria for indications for surgery in each group of CHD must be established, and any associated coronary artery abnormalities must be ruled out.

Adult↗
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↗