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Biomedical subjects

T Akasaka

Publications and source records attributed to T Akasaka.

At least 235 records · Page 13Linked to original sources
PubMed1987

Color Doppler flow mapping in cardiomyopathies and prosthetic valves.

The clinical significance of color Doppler flow mapping was assessed in patients with cardiomyopathies and prosthetic valves. Left and right ventricular obstruction and mitral regurgitation can be detected in patients with hypertrophic cardiomyopathy. Specific flow patterns in the left ventricle are clearly demonstrated in dilated cardiomyopathy. Concomitant regurgitation is easily detected in patients with dilated cardiomyopathy. The major role of this technique in patients with prosthetic valves exists in the detection of prosthetic valve regurgitation. In bioprosthetic valves, differentiation between transvalvular and paravalvular regurgitation is possible. The specific complications following the mechanical valve implantation, such as an aorto-right ventricular and aorto-left ventricular communication, can be detected using this technique. Although some problems remain, this technique is useful in the management of patients with cardiomyopathies and prosthetic valves.

Bioprosthesis↗
PubMed1987

Value and limitations of color Doppler flow mapping in the detection and semiquantification of valvular regurgitation.

We compared color Doppler flow mapping data to angiographic data in 294 patients with suspected valvular regurgitation. Thirty-one patients had rheumatic mitral regurgitation and 37 had mitral regurgitation due to mitral valve prolapse by angiography. Ten patients had no angiographic regurgitation (4 rheumatic, 6 prolapse). The remaining patients included 86 with suspected aortic regurgitation and 130 with suspected tricuspid regurgitation. Angiographically 74 had aortic regurgitation and 111 tricuspid regurgitation. The maximum size of regurgitant jets was evaluated in each patient by color flow mapping. The width of the jets was also taken into consideration. In 29 of the 31 with rheumatic regurgitation and 67 of the 74 with aortic regurgitation by angiography, abnormal regurgitant signals were detected by color flow mapping. In both rheumatic mitral regurgitation and aortic regurgitation, color Doppler estimation of the jets correlated well with angiographic grading. The regurgitant jets in these regurgitation were not eccentric. In the 37 with mitral regurgitation in mitral valve prolapse by left ventriculography, abnormal jets were detected in 35 by color flow mapping. However, the regurgitant jets were eccentric and color Doppler estimation of the jets correlated poorly with angiographic grading. In patients with tricuspid regurgitation, color Doppler grading of regurgitation correlated poorly with right ventriculographic grading. A color Doppler underestimation was observed in 48%. In conclusion, color Doppler flow mapping is useful in the noninvasive detection and semiquantification of rheumatic mitral regurgitation and aortic regurgitation having non-eccentric jets, although this technique often underestimates the severity of regurgitation in mitral valve prolapse.

Aortic Valve Insufficiency↗
PubMed1987

Age-related valvular regurgitation: a study by pulsed Doppler echocardiography.

To assess the prevalence of valvular regurgitation in the aged, we studied 176 apparently healthy volunteers with no history or physical evidence of cardiac abnormality. Their ages ranged from 40 to 90 (66 +/- 14, mean +/- SD) years. We examined these subjects by pulsed Doppler echocardiography combined with two-dimensional echocardiography to determine the prevalence of valvular regurgitation. Regurgitation began to appear in subjects in their fifties, increasing in prevalence with advancing age (r = .81, p less than .001), and was documented in all over age 80. Similarly, regurgitation involving more than one valve appeared in those 60 years and older, and was very common (89%) in subjects in their eighties. With each type of valvular regurgitation, the prevalence of each type of regurgitation increased with aging, but this tendency was most prominent for aortic regurgitation. We conclude that (1) single or multivalvular regurgitation as detected by pulsed Doppler echocardiography is very common in the aged and may be considered a normal finding in the absence of other evidence of heart disease, and (2) the high prevalence of regurgitation in the aged must be taken into account when Doppler examinations are being performed.

Adult↗
PubMed1987

[Echocardiographic characteristics and clinical significance of the spontaneous contrast echoes].

Spontaneous echocardiographic contrast is caused by increased ultrasonic density in the cardiac chambers or great vessels, or both, with the characteristic flow pattern of blood, but in the absence of any intravascular injections. This study demonstrated the clinical features and characteristics of the echocardiographic findings of eight patients with spontaneous contrast echoes. Spontaneous contrast echoes were observed in the right heart in five patients, and in the left heart in two. In one patient spontaneous contrast echoes were observed in the right and left heart. All six patients with spontaneous contrast echoes in the right heart had impaired liver function. In these patients, we observed that spontaneous contrast reaching the heart via the hepatic vein on two-dimensional echocardiography. In one patient with atrial septal defect, these contrast echoes were also recognized in the superior mesenteric vein and portal vein. Since capillary beds normally remove ultrasound contrast, the failure of this function suggests porta-systemic shunting in or around the liver. All three patients with spontaneous contrast echoes in the left heart had prosthetic valve dysfunction including paravalvular or transvalvular regurgitation, and consequent hemolysis. Under these conditions, water-vapor bubbles may be formed because of an exhaust pressure decrease due to the Bernoulli effect, or gases may be released from erythrocytes during hemolysis. These water-vapor bubbles or gases could be the cause of spontaneous contrast echoes in the left heart. In conclusion, spontaneous contrast echoes in the right heart are produced by gas absorbed from the intestine because of porta-systemic shunting. The cause of spontaneous left-sided heart echo contrast may be related to prosthetic valve regurgitation, and consequently to hemolysis.

Adult↗
PubMed1987

[A case of giant hydronephrosis with renal pelvic calcification].

A 26-year-old man had asymptomatic macroscopic hematuria. A left hydronephrotic sac outlined with a thin curvilinear shadow of calcium deposition was found in a plain film and stenosis at the ureteropelvic junction (UPJ) in a retrograde pyelogram. Left nephrectomy was performed and the fluid content was 1330 ml. Histologic examination showed subepithelial calcification of the renal pelvis and fibrous proliferation at the UPJ.

Adult↗
PubMed1987

[Evaluation of preoperative bladder tumor staging].

Twenty-eight out of 90 patients with bladder tumor seen from 1979 to 1982 were examined by CT, pelvic angiography, cystography and bimanual digital palpation for staging diagnosis preoperatively. Twenty-two patients underwent total cystectomy, and the other 6 patients underwent partial cystectomy. Preoperative staging (T) and postoperative histopathological staging (pT) were compared to define the diagnostic accuracy. The accuracy rate with CT was 20.0%, that with pelvic angiography, 29.4%, that with cystography 33.3%, and that with bimanual digital palpation 47.1%. Digital palpation had a better diagnostic accuracy rather than other examinations.

Aged↗
PubMed1986

[Mechanical and electrocardiographic sequence of coronary artery occlusion: an echocardiographic study during coronary angioplasty].

The detection of regional myocardial dysfunction due to acute ischemic event has been limited almost entirely to experimental animal models. In human subjects, it has been limited to the observations during spontaneously-occurring or exercise-induced ischemic events. Recently, percutaneous transluminal coronary angioplasty (PTCA) provides an opportunity to study such dysfunction as the result of repeated interruptions of coronary blood flow. Echocardiograms and electrocardiograms were simultaneously recorded immediately before, during, and after 21 episodes of complete interruptions of coronary blood flow by PTCA in 11 patients. No patient had asynergy of the left ventricle either by two-dimensional echocardiography (2DE) or angiography. All patients had isolated single coronary artery stenosis including the left anterior descending artery in nine, left circumflex artery in one and right coronary artery in one. Recordings of M-mode and 2DE were successfully obtained in 10 patients. After balloon inflation, regional asynergy in the distribution of the instrumented coronary artery appeared in all 10 patients. Hypokinesis developed 9 +/- 3 (means +/- SD) sec after balloon inflation and progressed rapidly to akinesis or dyskinesis. At the same time, decreased systolic thickening of the left ventricular wall appeared in some patients in relation to the development of regional asynergy. However, systolic thinning of the left ventricular wall was not noted in all. The regional asynergy preceded ischemic electrocardiographic changes and had no relation to chest pain. Left ventricular wall motion began to normalize 12 +/- 3 sec after balloon deflation. Thereafter, transient hyperkinesis of the left ventricle developed. The first ischemic electrocardiographic change was a negative U wave which appeared 13 +/- 7 sec after coronary occlusion and remained 3 to 4 sec. Tall T waves were recorded at 28 +/- 12 sec and significant ST elevations developed 31 +/- 11 sec, after balloon inflation. These electrocardiographic changes invariably occurred only after the onset of wall motion abnormalities. Normalization of T waves was recognized at 17 +/- 16 sec and ST segment deviation were no longer present at 18 +/- 10 sec, after reperfusion. These electrocardiographic changes also preceded normalization of regional myocardial dysfunction. In conclusion, left ventricular wall motion abnormalities after coronary occlusion invariably precede the electrocardiographic changes, and begin to normalize after reperfusion prior to the electrocardiographic recovery.

Adult↗
PubMed1986

[Non-rheumatic multivalvular regurgitation in an older population: a pulsed Doppler echocardiographic study].

To assess the incidence of valvular regurgitation, 180 patients more than 40 years of age without cardiac symptoms were studied by pulsed Doppler echocardiography. The 180 patients were categorized by age as group 1, 40 to 49 years; group 2, 50 to 59 years; group 3, 60 to 69 years; group 4, 70 to 79 years; and group 5, more than 80 years of age. The incidence of valvular regurgitant flow signals increased significantly with age. Multivalvular regurgitation were often detected in groups 4 and 5. Furthermore, acoustically silent regurgitation at each valve was frequently noted (71 of 85 cases with valvular regurgitant flow signal: 84%). Mitral valve prolapse was diagnosed by two-dimensional echocardiography in 27 patients, but a mid-systolic click or pansystolic murmur with late-systolic accentuation was not noted. In conclusion, valvular regurgitations were common in the aged who lacked auscultatory findings.

Adult↗
PubMed1986

[Value of right ventricular and atrial collapse in identifying cardiac tamponade].

Collapse of the right ventricle and right and left atria is observed in cardiac tamponade. To assess the diagnostic value of each collapse component in identifying cardiac tamponade, two-dimensional and M-mode echocardiograms were recorded simultaneously with the measurement of intrapericardial pressure in five patients as they underwent pericardiocentesis. Before pericardiocentesis, each patient had evidence of right ventricular and right atrial collapse. In addition, left atrial collapse was observed in four patients. During pericardiocentesis, left atrial collapse initially resolved accompanied by a drop in pressure in the pericardial sac. Continuous drainage of pericardial effusion resulted in significant symptomatic improvement and the cessation of paradoxical pulse at the point of resolution of right ventricular collapse. However, right atrial collapse persisted after resolution of right ventricular collapse, but it was absent when pericardiocentesis was completed. Injection of saline solution with heparin into the pericardial sac for cleansing initially caused right atrial collapse, while right ventricular collapse developed with the appearance of cardiac tamponade. In one patient, the simultaneous recording of right ventricular and intrapericardial pressures and two-dimensional echocardiograms demonstrated that right ventricular collapse occurred early in diastole, when intrapericardial pressure exceeded right ventricular pressure. In conclusion, right ventricular collapse is the most reliable sign of cardiac tamponade. Right atrial collapse occurs in the early stage of cardiac tamponade. Left atrial collapse appears very late in the course of hemodynamic deterioration due to cardiac tamponade.

Adult↗
PubMed1986

[A case of primary ureteral carcinoma in the duplicated renal pelvis and ureter diagnosed by transurethral uretero-renoscopy].

We present a case of primary ureteral carcinoma in the duplicated renal pelvis and ureter diagnosed by transurethral uretero-renoscopy. The case was of a 78-year-old man with the complaint of sudden asymptomatic macrohematuria. An excretory urogram strongly suggested the presence of duplication of the right collecting system, and cystoscopy revealed a gross hematuria from the right ureteral orifice. A retrograde ureteropyelogram revealed incomplete duplication of the right renal pelvis and ureter fused at about the ureter crossing over the iliac vessels, and a polyp-like filling defect in the lower segment of duplicated ureter at about 4 cm from the fusion of the ureters. Transurethral uretero-renoscopy was employed to investigate the filling defect, and a papillary tumor extended into the lower segment of duplicated ureter was revealed. Tumor was resected by a rigid operating instrument under transurethral uretero-renoscopy. The pathological diagnosis was grade I-transitional cell carcinoma of the ureter, so that right total nephroureterectomy with partial cystectomy was carried out subsequently. Surgical specimen after right total nephroureterectomy with partial cystectomy showed no other tumor in the pelvis or ureter macroscopically, and histopathological studies of surgical specimens were no evidence of malignancy. We believe that transurethral uretero-renoscopy significantly increases the diagnostic accuracy in determining the nature of upper urinary tract lesions, and this procedure is indispensable in the diagnosis of ureteral tumors. The present case was the 7th case of primary ureteral carcinoma in the duplicated renal pelvis and ureter in the Japanese literature.

Aged↗
PubMed1985

[Experience in using a ureterorenoscope in 14 cases].

We carried out studies using an ureterorenoscope in 14 cases, including 13 patients suffering from an ureteral stone. The stone was smaller than 1 cm and existed in lower and middle portion. The other patient had a foreign substance, which was a double J-stent catheter that had been passed into the middle portion of the ureter accidentally. Initially, the size and course of ureter, the position of stone and foreign substance were ascertained using a retrograde pyelogram. The patients were placed in a lithotomy position under spinal anesthesia or epidural anesthesia. The ureterorenoscope was inserted into the bladder through urethra and the instrument was further extended through ureteral orifice and ureteral lumen to the position of the calculus or foreign substance while observing the procedure. Once the calculus or foreign substance was observed, a 4F Pfister-Schwartz stone retriever or forceps was inserted through working channel. After coming in contact with the stone or foreign substance, the matter was removed while observing it with the scope. The foreign substance and 77% of the stones observed were removed by this procedure and the usefulness of the ureterorenoscope was successfully demonstrated in the cases. However, on the other hand, of these 14 cases, 2 (14%) experienced ureteral injury. In one case, the ureter was penetrated by the scope; and in another, injury occurred during the biopsy of the ureteral wall. Therefore, it is our opinion that more careful use of the ureterorenoscope is necessary to prevent these types of injuries.

Adult↗