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Dive into the research topics where Yasuko Yamaura is active.

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Featured researches published by Yasuko Yamaura.


Circulation | 2005

Mitral annulus flattens in ischemic mitral regurgitation: geometric differences between inferior and anterior myocardial infarction: a real-time 3-dimensional echocardiographic study.

Nozomi Watanabe; Yasuo Ogasawara; Yasuko Yamaura; Nozomi Wada; Takahiro Kawamoto; Eiji Toyota; Takashi Akasaka; Kiyoshi Yoshida

Background—New surgical strategies to restore the saddle shape of the mitral annulus are expected to increase annuloplasty effectiveness. Preoperative and postoperative configuration of the curved annulus, however, is difficult to quantify with 2-dimensional echocardiography. We sought to investigate the geometric deformity in the mitral annulus in ischemic mitral regurgitation (MR), comparing inferior and anterior myocardial infarction (MI) with the use of a custom quantitation software system with transthoracic 3-dimensional echocardiography. Methods and Results—We performed real-time 3-dimensional echocardiography in 23 patients with ischemic MR attributable to inferior MI or anterior MI and in 10 controls. Three-dimensional data were cropped into 18 radial planes, and we manually marked the annulus in mid systole. Three-dimensional annular images were reconstructed, and annular circumferences, areas, and heights were quantified. Annulus was significantly more dilated and flattened in ischemic MR than in controls and was further deformed in anterior MI as compared with inferior MI (control: circumference 9.9±0.7 cm, area 9.6±0.5 cm2, height 5.0±0.7 mm; inferior MI: circumference 11.5±1.2 cm [P<0.01 compared with control], area 11.4±2.0 cm2 [P<0.05 compared with control], height 3.5±1.6 mm [P<0.05 compared with control]; anterior MI: circumference 14.2±2.4 cm [P<0.0001 compared with control, P<0.05 compared with inferior MI], area 13.7±2.8 cm2 ]P<0.01 compared with control, P<0.05 compared with inferior MI], height 1.7±1.5 mm [P<0.0001 compared with control, P<0.05 compared with inferior MI]). Conclusions—Mitral annulus flattens in ischemic MR. Deformity of the mitral annulus was greater in anterior MI group than in the inferior MI group.


Circulation | 1990

Assessment of mitral regurgitation by biplane transesophageal color Doppler flow mapping.

Yoshida K; Junichi Yoshikawa; Yasuko Yamaura; Takeshi Hozumi; Takashi Akasaka; T Fukaya

To test the role of recently developed biplane transesophageal color Doppler echocardiography in the assessment of severity of mitral regurgitation, we examined 51 patients undergoing cardiac catheterization and left ventriculography. Transesophageal color Doppler flow imaging detected mitral regurgitation in all 32 patients proved to have this lesion. In 10 of 16 patients without mitral regurgitation by angiography, mitral regurgitation signals were detected by transesophageal color Doppler flow imaging. Thus, the sensitivity and specificity of transesophageal color Doppler echocardiography for the detection of mitral regurgitation were 100% and 38%, respectively. There was some correlation between the regurgitant jet area from the longitudinal plane and angiographic grading. An improved angiographic correlation was achieved with the regurgitant jet area from the transverse plane. The best correlation with angiography was obtained when the maximum regurgitant jet area from two planes (the greater of the two measurements, each from a different plane) was considered. There was a significant difference in the maximum regurgitant jet area between none and mild (p less than 0.01), mild and moderate (p less than 0.001), and moderate and severe (p less than 0.01) mitral regurgitation. The maximum regurgitant jet area of less than 1.5 cm2 predicted the angiographic grading as none with a sensitivity and specificity of 88% and 94%, respectively. The maximum regurgitant jet of between 1.5 and 4 cm2 predicted the angiographic grading as mild with a sensitivity and specificity of 82% and 95%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)


The Annals of Thoracic Surgery | 1995

Comparison of the Carpentier and Duran prosthetic rings used in mitral reconstruction

Yukikatsu Okada; Toyo Shomura; Yasuko Yamaura; Junichi Yoshikawa

This clinical study was undertaken to evaluate the Duran flexible ring and the Carpentier rigid ring in terms of mitral annulus motion, transmitral flow and left ventricular function. Twenty-six patients (11 receiving rigid rings and 15, flexible rings) with normal sinus rhythm and with no or only trivial mitral valve regurgitation after surgical repair were selected. Angiograms demonstrated no significant differences in left ventricular systolic function between the two groups of patients. The area of the mitral annulus with the flexible ring significantly changed during the cardiac cycle. There were significant differences in the left ventricular fractional shortening (rigid ring, 35.8%; flexible ring, 43.4%) and in the peak velocity (rigid ring, 222 cm/s; flexible ring, 186 cm/s) at peak exercise. These data suggest that the flexible ring interferes less with the normal movements of the mitral annulus during the cardiac cycle, and that, under exercise conditions, it performs better than the rigid ring. We therefore conclude that mitral valve reconstruction using the Duran flexible ring is advantageous in patients with mitral regurgitation due to degenerative disease and sinus rhythm.


Circulation | 1990

Detection of left main coronary artery stenosis by transesophageal color Doppler and two-dimensional echocardiography.

Yoshida K; Junichi Yoshikawa; Takeshi Hozumi; Yasuko Yamaura; Takashi Akasaka; T Fukaya; H Kato

Although transthoracic two-dimensional echocardiography can detect dilation of the coronary arteries, the reliability of this technique in the detection of coronary artery stenosis is still doubtful. The purpose of this study was to test the ability of newly developed biplane transesophageal color Doppler and two-dimensional echocardiography in the detection of left main coronary artery stenosis. Blood flow in the left main coronary artery was detected in 57 of 67 (85%) patients by transesophageal color Doppler flow imaging. Using transesophageal two-dimensional echocardiography, adequate images of the full length of the left main coronary artery and identification of the bifurcation were obtained in 60 of 67 (90%) patients. Transesophageal echocardiography clearly showed significant (greater than or equal to 50%) narrowing of the coronary lumen in 10 of 11 patients (sensitivity, 91%) and insignificant narrowing or no abnormalities of the coronary lumen in the other 49 patients (specificity, 100%). The positive predictive accuracy for left main coronary artery disease was 100%, and the negative predictive accuracy was 98%. This preliminary study suggests that biplane transesophageal color Doppler and two-dimensional echocardiography appears to be a feasible noninvasive technique for imaging the left main coronary artery and detecting hemodynamically significant luminal obstruction.


Circulation | 1989

Assessment of left-to-right atrial shunting after percutaneous mitral valvuloplasty by transesophageal color Doppler flow-mapping.

Yoshida K; Junichi Yoshikawa; Takashi Akasaka; Yasuko Yamaura; M Shakudo; Takeshi Hozumi; T Fukaya

To evaluate left-to-right shunts after percutaneous balloon mitral valvuloplasty, we studied 15 consecutive patients by using transesophageal color Doppler flow-imaging system. Transesophageal color Doppler examinations were performed five times in each patient (before valvuloplasty and 1 day, 1 week, 1 month, and 6 months after valvuloplasty). No shunt flow was observed before valvuloplasty. On 1 day after mitral valvuloplasty, transesophageal color Doppler echocardiography demonstrated left-to-right shunts in 13 (87%) of 15 patients. However, a significant oxygen step-up was present in the right heart in only one patient. The mean diameter of the interatrial septal defect detected by transesophageal two-dimensional echocardiography was 1.8 +/- 1.0 mm. The mean velocity of left-to-right shunting flow measured by high-pulse repetition frequency Doppler technique was 0.83 +/- 0.38 m/sec. One week after the procedure, left-to-right shunt flow was detected in 11 (73%) patients. One month after valvuloplasty, left-to-right shunting flow was detected in seven (47%) of 15 patients. There was a significant decrease in the diameter of an interatrial septal defect between 1 day and 1 week (p less than 0.01), between 1 week and 1 month (p less than 0.01), and between 1 month and 6 months (p less than 0.05). Six months after valvuloplasty, left-to-right shunting flow remained in three (20%) patients. By using transthoracic color Doppler echocardiography, we detected left-to-right shunting flow in two patients on 1 day after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of the American College of Cardiology | 2001

Noninvasive detection of total occlusion of the left anterior descending coronary artery with transthoracic doppler echocardiography

Nozomi Watanabe; Takashi Akasaka; Yasuko Yamaura; Maki Akiyama; Yuji Koyama; Norio Kamiyama; Yoji Neishi; Shuichiro Kaji; Yasuhiro Saito; Kiyoshi Yoshida

OBJECTIVES The purpose of this study was to evaluate the value of transthoracic Doppler echocardiography (TTDE) for the noninvasive detection of total left anterior descending coronary artery (LAD) occlusion. BACKGROUND Total coronary occlusion is associated with an adverse long-term prognosis, and mechanical revascularization may be required for the patient with total coronary occlusion. However, a noninvasive diagnosis of total coronary occlusion before coronary angiography (CAG) has been difficult, especially in patients without clinical signs. METHODS We studied 103 consecutive patients who underwent CAG for the evaluation of coronary artery disease. The study group consisted of 16 patients with total LAD occlusion (group A) and 87 patients without total LAD occlusion (group B). Coronary flow velocity in the mid-portion of the LAD was recorded by TTDE. RESULTS Adequate spectral Doppler recordings of diastolic flow in the LAD were obtained in 98 study patients (95%; 15 patients in group A and 83 patients in group B). In group A, retrograde LAD flow was obtained in 14 (93%) of 15 patients. The mean diastolic velocity of the retrograde flow was 21.0 +/- 6.1 cm/s. In group B, antegrade LAD flow was obtained in all 83 patients (100%). The mean diastolic velocity of the antegrade flow was 21.5 +/- 7.1 cm/s. Retrograde LAD flow by TTDE had a sensitivity of 93% and a specificity of 100% for the detection of total LAD occlusion. CONCLUSIONS Retrograde flow in the LAD by TTDE is a highly sensitive and specific finding that can be used to noninvasively diagnose total LAD occlusion.


Circulation | 1990

Value of acceleration flows and regurgitant jet direction by color Doppler flow mapping in the evaluation of mitral valve prolapse.

Yoshida K; Junichi Yoshikawa; Yasuko Yamaura; Takeshi Hozumi; M Shakudo; Takashi Akasaka; H Kato

To clarify the role of color Doppler echocardiography in the evaluation of mitral valve prolapse, we studied 49 consecutive patients in whom the sites of mitral valve prolapse were confirmed at the time of operation. The study group consisted of 22 patients with anterior leaflet prolapse, 24 patients with posterior leaflet prolapse, and three patients with multiple scallop prolapse (one patient with both anterior leaflet and middle scallop prolapse, and two patients with both medial and lateral scallop prolapse). Two-dimensional echocardiographic diagnosis of anterior leaflet prolapse was correct in all patients. The diagnosis of posterior leaflet prolapse by two-dimensional echocardiography, however, was mistaken as anterior leaflet prolapse in 16 (13 patients with medial scallop prolapse and three patients with lateral scallop prolapse) of the 24 patients according to current diagnostic criteria for mitral valve prolapse. Eight patients with middle scallop prolapse were diagnosed correctly by two-dimensional echocardiography. Acceleration flows in the left ventricle were observed by color Doppler echocardiography in all 49 patients. The sites of acceleration flows detected by color Doppler echocardiography coincided with those of prolapse confirmed in all at the time of operation. There was a significant correlation between the maximum area of acceleration flow signals and severity of mitral regurgitation estimated by angiography. In the 13 patients with medial scallop prolapse and the three patients with lateral scallop prolapse, a regurgitant jet originated from a bulged portion of the posterior leaflet and was directed toward the opposite left atrial cavity to the bulged portion by short-axis images of color Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of the American College of Cardiology | 1989

Noninvasive diagnosis of coronary artery fistula by doppler color flow mapping

Masahiro Shakudo; Junichi Yoshikawa; Kiyoshi Yoshida; Yasuko Yamaura

Sixteen patients with coronary artery fistula proved by coronary angiography or surgery were studied using two-dimensional echocardiography and Doppler color flow mapping. The coronary artery fistula drained into the right atrium in 4 patients, the right ventricle in 2 and the pulmonary artery in 10. The dilated coronary artery was visualized in 7 of the 16 patients with a fistula, as compared with none of the 40 control subjects. These 7 patients included 5 of 6 patients with a fistula draining into the right atrium or right ventricle and only 2 of 10 patients with a fistula draining into the pulmonary artery. Abnormal flow signals in the dilated coronary artery were visualized with Doppler color flow mapping in five of these seven patients. Color flow imaging visualized abnormal flow signals with mosaic appearance in the pulmonary artery in eight patients, the right atrium in four and the right ventricle in two. The chamber in which abnormal signals were detected corresponded with the entry site of the fistula by angiography. Intraoperative imaging during surgical repair was needed in two cases to confirm ligation of all arteries feeding into the fistula network. In conclusion, Doppler color flow imaging is diagnostically useful to visualize shunt flows originating from the opening or exit of a coronary artery fistula. Furthermore, intraoperative use of this technique may provide confirmation of successful surgical ligation of the fistula.


Journal of the American College of Cardiology | 1990

DIRECT VISUALIZATION OF RUPTURED CHORDAE TENDINEAE BY TRANSESOPHAGEAL TWO-DIMENSIONAL ECHOCARDIOGRAPHY

Takeshi Hozumi; Junichi Yoshikawa; Kiyoshi Yoshida; Yasuko Yamaura; Takashi Akasaka; Shakudo M

To determine the value of transesophageal echocardiography in the detection of ruptured chordae tendineae, 28 patients who had surgical therapy for pure mitral regurgitation were evaluated prospectively by conventional transthoracic and transesophageal two-dimensional echocardiography. Seventeen patients (Group I) had ruptured chordae tendineae and 11 (Group II) had intact chordae tendineae. Transthoracic echocardiography detected ruptured chordae tendineae in 6 patients from Group I (sensitivity 35%) and flail leaflets in 11 patients from Group I (sensitivity 65%). Transesophageal echocardiography disclosed ruptured chordae tendineae in all 17 Group I patients (sensitivity 100%); the sensitivity was significantly higher than that of transthoracic echocardiography. No abnormal chordal echoes were visualized in any patient from Group II by either transthoracic or transesophageal echocardiography (specificity 100%). Transesophageal echocardiography is a highly sensitive method for detecting ruptured chordae tendineae and is superior to transthoracic echocardiography in establishing its diagnosis.


Circulation | 1991

Assessment of aortic regurgitation by the acceleration flow signal void proximal to the leaking orifice in cinemagnetic resonance imaging.

Yoshida K; Junichi Yoshikawa; Takeshi Hozumi; Takashi Akasaka; Yasuko Yamaura; Shinichi Minagoe; H Nakajima; T Miyamoto

BackgroundThe proximal acceleration flow region is a laminar flow field that is located immediately upstream from the leaking orifice. The purpose of this study was to evaluate whether cinemagnetic resonance imaging can provide information regarding the proximal acceleration flow region in patients with aortic regurgitation and to analyze the relation between the area of the proximal acceleration flow delineated by cinemagnetic resonance imaging and the severity of aortic regurgitation delineated by angiography. Methods and ResultsThirty-eight consecutive patients who underwent aortography were examined by cinemagnetic resonance imaging. The region of proximal flow acceleration was identified as a semicircular-shaped signal void in the aorta during diastole. Cinemagnetic resonance imaging detected the proximal acceleration flow region in 26 of the 30 patients who were proved to have this lesion (sensitivity, 87%). In eight patients without aortic regurgitation according to aortography, no proximal acceleration flow region was detected (specificity, 100%). The area of the acceleration flow signal void from the long-axis view was well correlated with angiographic degree of aortic regurgitation. ConclusionsCinemagnetic resonance imaging is useful in detecting the proximal acceleration flow region and permits noninvasive assessment of the severity of aortic regurgitation. (Circulation 1991;83:1951—1955)

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Takashi Akasaka

Wakayama Medical University

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Takeshi Hozumi

Wakayama Medical University

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Eiji Toyota

Kawasaki Medical School

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Nozomi Wada

Kawasaki Medical School

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