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Dive into the research topics where Hirotsugu Mihara is active.

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Featured researches published by Hirotsugu Mihara.


European Journal of Echocardiography | 2014

A revised methodology for aortic-valvar complex calcium quantification for transcatheter aortic valve implantation

Hasan Jilaihawi; Raj Makkar; Mohammad Kashif; Kazuaki Okuyama; Tarun Chakravarty; Takahiro Shiota; Gerald Friede; Mamoo Nakamura; Niraj Doctor; Asim Rafique; Kentaro Shibayama; Hirotsugu Mihara; Alfredo Trento; Wen Cheng; John D. Friedman; Daniel S. Berman; Gregory P. Fontana

AIMS We sought to optimize a method for quantification of the calcium in the aortic-valvar complex for the prediction of significant paravalvular leak (PVL) after transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS All patients had severe symptomatic aortic stenosis and were treated with balloon-expandable TAVI (Sapien/Sapien-XT, Edwards Lifesciences LLC, Irvine, CA, USA). In order to correct for precise annular sizing, only patients with available contrast computed tomography (CT) data for measurements were included (n = 198). Paravalvular leak was quantified using peri-procedural transoesophageal echocardiography by Valve Academic Research Consortium-2 (VARC-2) criteria (grade ≥ moderate was considered significant). A detailed region-of-interest methodology separated quantification of calcium in each of the aortic leaflets to that in the left ventricular outflow tract (LVOT) and was used to predict PVL in receiver operator characteristic curve analyses. For non-contrast scans, the greatest discriminatory value for PVL was seen at the 450 Hounsfield Unit (HU) threshold for detection (volume ≥626 mm(3)), whereas for contrast scans it was at 850 HU (≥235 mm(3)). Left ventricular outflow tract calcium predicted PVL but only as a binary variable with no incremental value of quantification. In a multivariable binary logistic regression model, annulus area ≥ prosthesis area (OR 3.5, 95% CI 1.5-8.2, P = 0.005), contrast leaflet calcium volume (850-HU threshold) ≥235 mm(3) (OR 2.8, 95% CI 1.2-6.7, P = 0.023), and presence of LVOT calcium (OR 2.8, 95% CI 1.2-7.0, P = 0.022) were independent predictors for PVL ≥ moderate. CONCLUSION Both leaflet and LVOT calcium are significant predictors of PVL and exert an important synergistic influence on this complication, even in appropriately sized valves. With careful attention to thresholds for detection, clinically relevant leaflet calcium volumes can be identified with either non-contrast or contrast CT scans.


Circulation-cardiovascular Imaging | 2014

Evaluation of Vegetation Size and Its Relationship With Embolism in Infective Endocarditis A Real-Time 3-Dimensional Transesophageal Echocardiography Study

Javier Berdejo; Kentaro Shibayama; Kenji Harada; Jun Tanaka; Hirotsugu Mihara; Swaminatha V. Gurudevan; Robert J. Siegel; Takahiro Shiota

Background—Two-dimensional (2D) echocardiography studies have shown that the maximum length of vegetation (MLV) ≥10 mm is a predictor of embolic events (EEs) in patients with infective endocarditis. However, 2D measurements probably underestimate the vegetation dimensions. In this study, we evaluated the feasibility of real-time 3-dimensional transesophageal echocardiography (RT3DTEE) in determining MLV and its accuracy in identifying the risk for EEs compared with 2D transesophageal echocardiography (2DTEE). Methods and Results—We analyzed 60 patients with vegetations. RT3DTEE measurement of MLV was obtained with Advanced QLAB Quantification Software by cropping the 3D volume with the appropriate 2D plane to obtain the largest value. The standard 2DTEE images were also evaluated to determine the MLV. Major EEs were registered from medical records, and a logistic regression analysis was performed to determine the association between MLV and EEs. The RT3DTEE MLV was larger than the 2DTEE value with a mean difference of 3.2 mm (95% confidence interval, 2.1–4.2 mm). The best cut-off value for prediction of EEs was MLV ≥20 mm with RT3DTEE and MLV ≥16 mm with 2DTEE. The positive predictive value increased from 59.1% to 65.2% when RT3DTEE was used. The accuracy of classification of patients with EEs increased from 65% to 70% with this new technique. Conclusions—RT3DTEE is a feasible technique for the analysis of vegetation morphology and size that may overcome the shortcoming of 2DTEE, leading to a better prediction of the embolism risk in patients with infective endocarditis.


Circulation-cardiovascular Imaging | 2014

Effect of transcatheter aortic valve replacement on the mitral valve apparatus and mitral regurgitation: real-time three-dimensional transesophageal echocardiography study.

Kentaro Shibayama; Kenji Harada; Javier Berdejo; Hirotsugu Mihara; Jun Tanaka; Swaminatha V. Gurudevan; Robert J. Siegel; Hasan Jilaihawi; Raj Makkar; Takahiro Shiota

Background—The effect of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing the reduction of mitral regurgitation with or without mitral leaflet tethering after TAVR are poorly understood. The present 3-dimensional (3D) transesophageal echocardiography study aimed to elucidate early changes further in the structure and function of the mitral valve apparatus after TAVR. Methods and Results—We analyzed 90 patients (nontenting group, 56 patients and tenting group, 34 patients) who underwent TAVR using the Edwards SAPIEN and had intraprocedural 3D transesophageal echocardiography evaluation of the mitral valve. Of all patients, mitral regurgitation improved in 54%, remained the same in 38%, and worsened in 8% 1 day after TAVR. There were no statistically significant differences in mitral annular 3D parameters before and after TAVR in both groups. In the tenting group, tenting area (P<0.01) and tenting height (P<0.01) were decreased, and coaptation length was increased (P<0.05) after TAVR. In a multivariable analysis, the predictors of improved mitral regurgitation were the decrease of tenting area (odds ratio, 8.15; 95% confidence interval, 1.31–50.7; P<0.05) and the decrease of valvuloarterial impedance (odds ratio, 7.57; 95% confidence interval, 1.15–49.9; P<0.05) in the tenting group and the decrease of valvuloarterial impedance (odds ratio, 6.96; 95% confidence interval, 1.24–39.2; P<0.05) in the nontenting group. Conclusions—Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in mitral regurgitation after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.Background— The effect of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing the reduction of mitral regurgitation with or without mitral leaflet tethering after TAVR are poorly understood. The present 3-dimensional (3D) transesophageal echocardiography study aimed to elucidate early changes further in the structure and function of the mitral valve apparatus after TAVR. Methods and Results— We analyzed 90 patients (nontenting group, 56 patients and tenting group, 34 patients) who underwent TAVR using the Edwards SAPIEN and had intraprocedural 3D transesophageal echocardiography evaluation of the mitral valve. Of all patients, mitral regurgitation improved in 54%, remained the same in 38%, and worsened in 8% 1 day after TAVR. There were no statistically significant differences in mitral annular 3D parameters before and after TAVR in both groups. In the tenting group, tenting area ( P <0.01) and tenting height ( P <0.01) were decreased, and coaptation length was increased ( P <0.05) after TAVR. In a multivariable analysis, the predictors of improved mitral regurgitation were the decrease of tenting area (odds ratio, 8.15; 95% confidence interval, 1.31–50.7; P <0.05) and the decrease of valvuloarterial impedance (odds ratio, 7.57; 95% confidence interval, 1.15–49.9; P <0.05) in the tenting group and the decrease of valvuloarterial impedance (odds ratio, 6.96; 95% confidence interval, 1.24–39.2; P <0.05) in the nontenting group. Conclusions— Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in mitral regurgitation after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.


Circulation-cardiovascular Imaging | 2017

Functional Tricuspid Regurgitation Caused by Chronic Atrial Fibrillation: A Real-Time 3-Dimensional Transesophageal Echocardiography Study

Hiroto Utsunomiya; Yuji Itabashi; Hirotsugu Mihara; Javier Berdejo; Sayuki Kobayashi; Robert J. Siegel; Takahiro Shiota

Background— Functional tricuspid regurgitation (TR) with a structurally normal tricuspid valve (TV) may occur secondary to chronic atrial fibrillation (AF). However, the clinical and echocardiographic differences according to functional TR subtypes are unclear. Therefore, characterization of functional TR because of chronic AF (AF-TR) remains undetermined. Methods and Results— To investigate the prevalence of AF-TR, 437 patients with moderate to severe TR underwent 3-dimensional (3D) transesophageal echocardiography. TR severity was determined by the averaged vena contracta width on apical and parasternal inflow views. The prevalence of AF-TR was 9.2%, whereas that of functional TR because of left-sided heart disease was 45.3%. Clinical features of AF-TR included advanced age, female sex, greater right atrial than left atrial enlargement and lower systolic pulmonary artery pressure compared with left-sided heart disease-TR with sinus rhythm (all P <0.05). In 3D TV assessment, patients with AF-TR had a larger TV annular area with weaker annular contraction (both P <0.001) but a smaller tethering angle ( P <0.001) despite a similar leaflet coaptation status compared with patients with left-sided heart disease-TR with sinus rhythm. On multivariable analysis, only the TV annular area in midsystole (coefficient, 0.059; 95% confidence interval, 0.041–0.078 per 100 mm2; P <0.001) was associated with TR severity in AF-TR. The annular area was more closely correlated with the right atrial volume than right ventricular end-systolic volume in AF-TR ( P <0.001). Conclusions— AF-TR is not rare and is associated with advanced age and right atrial enlargement. TV deformations and their association with right heart remodeling differ between AF-TR and left-sided heart disease-TR. Our results suggest that in patients with TR secondary to AF, TV annuloplasty should be effective because this entity has annular dilatation without leaflet deformation.Background— Functional tricuspid regurgitation (TR) with a structurally normal tricuspid valve (TV) may occur secondary to chronic atrial fibrillation (AF). However, the clinical and echocardiographic differences according to functional TR subtypes are unclear. Therefore, characterization of functional TR because of chronic AF (AF-TR) remains undetermined. Methods and Results— To investigate the prevalence of AF-TR, 437 patients with moderate to severe TR underwent 3-dimensional (3D) transesophageal echocardiography. TR severity was determined by the averaged vena contracta width on apical and parasternal inflow views. The prevalence of AF-TR was 9.2%, whereas that of functional TR because of left-sided heart disease was 45.3%. Clinical features of AF-TR included advanced age, female sex, greater right atrial than left atrial enlargement and lower systolic pulmonary artery pressure compared with left-sided heart disease-TR with sinus rhythm (all P<0.05). In 3D TV assessment, patients with AF-TR had a larger TV annular area with weaker annular contraction (both P<0.001) but a smaller tethering angle (P<0.001) despite a similar leaflet coaptation status compared with patients with left-sided heart disease-TR with sinus rhythm. On multivariable analysis, only the TV annular area in midsystole (coefficient, 0.059; 95% confidence interval, 0.041–0.078 per 100 mm2; P<0.001) was associated with TR severity in AF-TR. The annular area was more closely correlated with the right atrial volume than right ventricular end-systolic volume in AF-TR (P<0.001). Conclusions— AF-TR is not rare and is associated with advanced age and right atrial enlargement. TV deformations and their association with right heart remodeling differ between AF-TR and left-sided heart disease-TR. Our results suggest that in patients with TR secondary to AF, TV annuloplasty should be effective because this entity has annular dilatation without leaflet deformation.


Journal of The American Society of Echocardiography | 2015

Impact of Device Landing Zone Calcification on Paravalvular Regurgitation after Transcatheter Aortic Valve Replacement: A Real-Time Three-Dimensional Transesophageal Echocardiographic Study

Hirotsugu Mihara; Kentaro Shibayama; Javier Berdejo; Kenji Harada; Yuji Itabashi; Robert J. Siegel; Mohammad Kashif; Hasan Jilaihawi; Raj Makkar; Takahiro Shiota

BACKGROUND Determinants of paravalvular regurgitation after transcatheter aortic valve replacement (TAVR) remain unclear. The purpose of this study was to investigate the impact of aortic valve calcification (AVC) on paravalvular regurgitation after TAVR using real-time three-dimensional transesophageal echocardiography. METHODS A total of 227 patients with severe aortic stenosis who underwent TAVR using the Edwards SAPIEN or SAPIEN XT valve were retrospectively analyzed. Severity of AVC was assessed on a visual scale ranging from 0 to 3 at the aortic annulus, the leaflets near the nadir, and the commissure. The shape of calcification was assessed by measuring the radial and circumferential lengths of annular calcification and by focusing on the calcification protruding into the left ventricular outflow tract from the annular level. Severity of paravalvular regurgitation was determined by the sum of the cross-sectional area of the vena contracta from two-dimensional or three-dimensional color Doppler transesophageal echocardiographic data. Significant paravalvular regurgitation was defined as at least a moderate grade. RESULTS After excluding 25 patients with inadequate image quality of three-dimensional and color Doppler data for analysis, AVC could be evaluated in 202 patients. Significant paravalvular regurgitation was occurred in 37 patients (18%). The sum of the AVC scale at the annulus was significantly correlated with the grade of paravalvular regurgitation, while those at the leaflets near the nadir and the commissure were not. As assessed by receiver operating characteristic curve analysis, the radial and circumferential length of the annular calcification had good discriminatory ability for significant paravalvular regurgitation, with areas under the curve of 0.91 and 0.81, respectively. On multivariate analysis, annular calcification with radial length ≥ 3.0 mm, circumferential length ≥ 8.0 mm, and calcification protruding into the left ventricular outflow tract were independently associated with significant paravalvular regurgitation. CONCLUSIONS Assessment of AVC by real-time three-dimensional transesophageal echocardiography is feasible and has good discriminatory value for paravalvular regurgitation in patients who undergo TAVR. Significant paravalvular regurgitation after TAVR is associated with the location and size of calcification at the aortic annulus and left ventricular outflow tract, not with its severity.


Journal of The American Society of Echocardiography | 2014

Comparison of Aortic Root Geometry with Bicuspid versus Tricuspid Aortic Valve: Real-Time Three-Dimensional Transesophageal Echocardiographic Study

Kentaro Shibayama; Kenji Harada; Javier Berdejo; Jun Tanaka; Hirotsugu Mihara; Yuji Itabashi; Takahiro Shiota

BACKGROUND An understanding of aortic root anatomy in bicuspid aortic valve (BAV) has not been well established. The aims of this three-dimensional transesophageal echocardiographic study were (1) to examine whether aortic root geometry differs between BAV and tricuspid aortic valve (TAV) and (2) to analyze the dynamic motion of the aortic annulus throughout cardiac cycle. METHODS A total of 66 patients with BAV (38 with severe aortic stenosis [AS]) and 66 age-, gender-, and body surface area-matched patients with TAV (36 with severe AS) who underwent three-dimensional transesophageal echocardiography were retrospectively enrolled. The dynamic motion of the aortic annulus was also analyzed in 40 selected patients (10 with BAV with severe AS, 10 with BAV without AS, 10 with TAV with severe AS, and 10 with TAV without AS). RESULTS The area of the aortic root in patients with BAV was larger than in those with TAV (aortic annulus, P < .001; sinus of Valsalva, P < .05; sinotubular junction, P < .01). There was a significant difference in circularity (4π × area/[perimeter](2)) of the sinus of Valsalva between patients with BAV and those with TAV (P < .001), although there were no differences in the shapes of the aortic annulus and the sinotubular junction between the two groups. In both patients with BAV and those with TAV, the aortic annulus in mid-systole was largest and most circular in cardiac cycle; on the other hand, in end-diastole, the aortic annulus was smallest and most elliptical (P < .001). CONCLUSIONS Three-dimensional transesophageal echocardiography successfully demonstrated significant differences in the size of the aortic root and the shape of the sinus of Valsalva between patients with BAV and those with TAV.


Echocardiography-a Journal of Cardiovascular Ultrasound and Allied Techniques | 2017

Vena contracta analysis by color Doppler three-dimensional transesophageal echocardiography shows geometrical differences between prolapse and pseudoprolapse in eccentric mitral regurgitation

Javier Berdejo; Maiko Shiota; Hirotsugu Mihara; Yuji Itabashi; Hiroto Utsunomiya; Takahiro Shiota

Evaluation of eccentric mitral regurgitation (MR) remains extremely difficult and the role played by its etiology, functional or degenerative, is not well understood. This study aimed to demonstrate the value of three‐dimensional transesophageal echocardiography (3DTEE) in the evaluation of eccentric MR identifying geometric differences in the vena contracta area between functional and degenerative etiologies.


Catheterization and Cardiovascular Interventions | 2017

Outcome of paravalvular leak repair after transcatheter aortic valve replacement with a balloon-expandable prosthesis.

Abhijeet Dhoble; Tarun Chakravarty; Mamoo Nakamura; Yigal Abramowitz; Rikin Tank; Hirotsugu Mihara; Geeteshwar Mangat; Hasan Jilaihawi; Takahiro Shiota; Raj Makkar

Significant paravalvular leak (PVL) occurs in up to 13% of patients after transcatheter aortic valve replacement (TAVR) with a balloon‐expandable bioprosthesis. Transcatheter PVL repair has emerged as a less invasive alternative for this problem.


European Journal of Echocardiography | 2017

Usefulness of 3D echocardiographic parameters of tricuspid valve morphology to predict residual tricuspid regurgitation after tricuspid annuloplasty

Hiroto Utsunomiya; Yuji Itabashi; Hirotsugu Mihara; Sayuki Kobayashi; Michele A. De Robertis; Alfredo Trento; Takahiro Shiota

Aims Tricuspid valve (TV) annuloplasty is an effective treatment for tricuspid regurgitation (TR). However, the impact of TV morphology on outcome of TV annuloplasty remains unknown. We sought to investigate the relationship between preoperative TV morphology and residual TR after annuloplasty. Methods and Results Two-dimensional transthoracic and three-dimensional (3D) transesophageal echocardiography were performed in 97 patients with functional TR before and after surgery. 3D quantitative assessment including annular dimension, tenting height and volume, and lengths and tethering angles of the 3 leaflets was performed. The TV morphological score was derived from the preoperative 3D echocardiography to score a leaflet mobility, leaflet thickening, subvalvular thickening, and calcification. TR severity was determined by the averaged vena contracta measured from the apical and parasternal inflow views. Multivariable analysis revealed that a shorter total leaflet length (P = 0.007), larger tenting volume (P < 0.001), and higher TV morphological score (P < 0.001) were independently associated with residual TR. A TV-Echo score was determined as a sum of points based on receiver operator characteristics analysis: total leaflet length >61.0 mm, 61.0 to 53.5 mm, and <53.5 mm; tenting volume <2.3 mL, 2.3 to 3.5 mL, and >3.5 mL; and TV morphological score <7, 7 to 18, and >18; each variable was associated with 0 and 1 point and 2 points, respectively. The TV-Echo score ≥2 was associated with significant residual TR with a sensitivity of 85.7% and a specificity of 71.0%. Conclusion In addition to tethering and short length of the leaflets, TV morphological abnormality predicted residual TR after TV annuloplasty.


European Journal of Echocardiography | 2017

Geometric changes in ventriculoaortic complex after transcatheter aortic valve replacement and its association with post-procedural prosthesis–patient mismatch: an intraprocedural 3D-TEE study

Hiroto Utsunomiya; Hirotsugu Mihara; Yuji Itabashi; Sayuki Kobayashi; Robert J. Siegel; Tarun Chakravarty; Hasan Jilaihawi; Raj Makkar; Takahiro Shiota

Aims Prosthesis–patient mismatch (PPM) after transcatheter aortic valve replacement (TAVR) leads to increased mortality. However, its peri-procedural determinants remain unknown. We investigated geometric changes in aortic annulus (AoA) and left ventricular outflow tract (LVOT) during TAVR by three-dimensional transoesophageal echocardiography (3D-TEE) and its association with post-procedural PPM. Methods and results A total of 131 patients with severe aortic stenosis underwent intraprocedural 3D-TEE during balloon-expandable TAVR. The severity of PPM was graded using the indexed effective orifice area calculated by Doppler echocardiography at discharge, with moderate defined as ≥0.65 and ⩽0.85 cm2/m2 and severe defined as <0.65 cm2/m2. 3D planimetered AoA area decreased after TAVR (P< 0.001), whereas the LVOT increased (P= 0.004). The eccentricity of both AoA and LVOT decreased after TAVR (both, P< 0.001). At discharge, the incidence of overall and severe PPM was 44 and 12%, respectively. Patients with PPM had a larger body surface area, smaller aortic valve area, and less frequent balloon dilation (all P< 0.05). Patients with PPM had a lower post-TAVR AoA area/pre-TAVR AoA area (91 ± 8 vs. 95 ± 7%, P= 0.001) than those without PPM. The post-TAVR AoA area/pre-TAVR AoA area was independently associated with overall PPM (odds ratio, 1.80; 95% CI, 1.06–3.05; P= 0.031) and severe PPM (odds ratio, 2.50; 95% CI, 1.05–5.36; P= 0.04). Additionally, a cut-off value of this ratio >86.3% had a sensitivity of 84% and a specificity of 44% for the prevention of severe PPM. Conclusion 3D-TEE can evaluate geometric changes in AoA and LVOT during balloon-expandable TAVR and predicts post-procedural PPM.

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Takahiro Shiota

Cedars-Sinai Medical Center

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Javier Berdejo

Cedars-Sinai Medical Center

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Yuji Itabashi

Cedars-Sinai Medical Center

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Robert J. Siegel

Cedars-Sinai Medical Center

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Kentaro Shibayama

Cedars-Sinai Medical Center

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Raj Makkar

Cedars-Sinai Medical Center

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Hasan Jilaihawi

Cedars-Sinai Medical Center

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Hiroto Utsunomiya

Cedars-Sinai Medical Center

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Jun Umemura

Cedars-Sinai Medical Center

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