Effects of blood pump orientation on performance: In vitro assessment of universal advanced ventricular assist device.

An advanced ventricular assist device (VAD), which is under development in our institution, has specific features that allow changes in the axial rotor position and pump performance by intrapump pressure difference. However, performance could be influenced by the pump orientation because of the effect of gravity on the rotor position. The purpose of this study was to evaluate the effects of pump orientation on the pump performance, including pulse pressure and regurgitant flow through the pump when the pump was stopped. Bench testing of the VAD was performed on a static or pulsatile mock loop with a pneumatic device to simulate the native ventricle. The pump performance, including pressure-flow curve, pulsatility, and regurgitant flow, was evaluated at several angles, ranging from -90° (inlet pointed upward) to +90° (inlet pointed downward) at pump speeds of 2000, 2500, 3000, and 3500 rpm. The pump performance was slightly lower at +90° at all rotational speeds, compared with -90°. The pulse pressure on the pulsatile mock loop (80 bpm) was 50 mm Hg without pump support, remained at 50 mm Hg during pump support, and was not changed by orientation (-90°, 0°, and +90°). When the pump was stopped, the regurgitant flow was near 0 L/min at all angles. Pump orientation had a minor effect on pump performance, with no effect on pulse pressure or regurgitant flow when the pump was stopped. This indicates that the effect of gravity on the rotor assembly is insignificant.

Continuous-flow total artificial heart: hemodynamic and pump-related changes associated with posture in a chronic calf model.

This study aimed to evaluate the effects of posture (sitting [lying down]/standing) on hemodynamic and pump-related parameters in calves implanted with our institution's continuous-flow total artificial heart (CFTAH). These parameters were analyzed with posture information in four calves that had achieved the intended 14-, 30-, or 90-day durations of implantation. In each animal, postoperative hourly data gathered throughout the study were used to compare average values with the animal sitting vs. standing. Pump flow became significantly higher in the standing than sitting position at the same pump speed (standing 7.9 ± 0.8, sitting 7.4 ± 1.0 L/min, p = 0.028). Systemic vascular resistance (SVR) and aortic pressure (AoP) were significantly lower in the standing than sitting position (SVR standing 779 ± 145, sitting 929 ± 206 dyne s/cm5, p = 0.027; AoP standing 93 ± 7, sitting 103 ± 7 mm Hg, p < 0.001). No substantial change occurred in pulmonary vascular resistance (PVR) or pulmonary arterial pressure (PAP) with posture (PVR standing 161 ± 39, sitting 164 ± 48 dyne s/cm5, p = 0.639; PAP standing 32 ± 3, sitting 33 ± 4 mm Hg, p = 0.340). Posture affected some hemodynamic and pump-related parameters in calves with CFTAH, with implications for patients with implanted pumps.

Ventricular-Arterial Coupling and Exercise-Induced Pulmonary Hypertension During Low-Level Exercise in Heart Failure With Preserved or Reduced Ejection Fraction.

BACKGROUND: Exercise-induced pulmonary hypertension (EIPH) may develop even at low workloads in heart failure (HF) patients. Ventricular-arterial stiffening plays an important role in the pathophysiology of HF with preserved ejection fraction (HFpEF). This study aimed to compare the response of ventricular-arterial coupling and PH during low-level exercise between HFpEF and HF with reduced EF (HFrEF). METHODS AND RESULTS: Echocardiography was performed at rest and during 10 W of bicycle exercise in HFpEF (n = 37) and HFrEF (n = 43). Load-independent contractility (end-systolic elastance [Ees], preload recruitable stroke work [PRSW], and peak power index [PWRI]), arterial afterload (arterial elastance [Ea]), and ventricular-arterial interaction (Ea/Ees) were measured with the use of a noninvasive single-beat technique. EIPH was defined as an estimated pulmonary arterial systolic pressure (PASP) of ≥50 mm Hg at 10 W of exercise. PASP was significantly increased during 10 W of exercise in both HF types, and ~50% of HFpEF patients developed EIPH. Arterial afterload was increased significantly during exercise in both groups. HFrEF and HFpEF patients showed a significant increase in LV contractility assessed by Ees, PRSW, and PWRI during exercise. Although Ea/Ees ratio decreased significantly in HFrEF, reduction in Ea/Ees was attenuated because of blunted Ees increases in patients with HFpEF compared with HFrEF. CONCLUSIONS: Even at low-level exercise, ~50% of HFpEF patients developed EIPH. Reduction in Ea/Ees was attenuated owing to less Ees increase in HFpEF compared with HFrEF. Further studies are needed to elucidate the association between ventricular-arterial coupling and EIPH in HFpEF.

Prognostic value of biventricular mechanical parameters assessed using cardiac magnetic resonance feature-tracking analysis to predict future cardiac events.

PURPOSE: To study and compare the prognostic value of cardiac magnetic resonance feature tracking (MR-FT) of biventricular strain parameters with a conventional method. MATERIALS AND METHODS: We retrospectively enrolled 364 patients undergoing clinically indicated cardiac MR examinations (1.5 or 3T scanner). Standard steady-state free precession (SSFP) images were used for analysis. Left ventricular (LV) and right ventricular (RV) ejection fraction (EF) were measured using conventional disk-area summation methods. Biventricular strain parameters were measured using MR-FT. All patients were followed to record major adverse cardiac events (MACEs). RESULTS: The correlations between LV volumes and LVEF using both methods were excellent (r = 0.87-0.98). RV strain parameters were modestly correlated with RVEF (r = 0.44-0.63). During a median follow-up of 15 months, 36 patients developed MACEs. All MR-FT-derived parameters except for RV global longitudinal strain were significantly associated with future MACEs (P < 0.05) in univariate analysis. In stepwise Cox proportional hazard models, RV global radial strain (RVGRS) provided incremental prognostic value in models adjusted for age, gender, conventional LVEF (hazard ratio 0.93; P = 0.029) or RVEF (hazard ratio 0.93; P = 0.038). LV global transverse strain (LVGTS) also offered additional value over age, gender, conventional LVEF (hazard ratio 0.94; P = 0.041), or RVEF (hazard ratio 0.94; P = 0.004). Kaplan-Meier analysis showed significant survival differences in subgroups stratified by the median value of LVGTS, RVGRS, and LVEF using MR-FT (all log-rank P < 0.05). CONCLUSION: Deformation analysis of both ventricles using MR-FT provided significant prognostic power similar to parameters obtained using conventional methods. MR-FT is a promising alternative both for ventricular chamber quantification and for providing information of future cardiac events. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1034-1045.

Left Atrial Remodeling in Segmental vs. Global Mitral Valve Prolapse　- Three-Dimensional Echocardiography.

BACKGROUND: Segmental and global mitral valve prolapse (MVP) comprise 2 representative phenotypes in this syndrome. While mitral regurgitation (MR) severity is a major factor causing left atrial (LA) remodeling in MVP, prominent mitral valve (MV) annulus dilatation in global MVP may specifically cause inferiorly predominant LA remodeling. We compared MV annulus and LA geometry in patients with segmental and global MVP.Methods and Results:LA volume as well as inferior, middle, and superior LA cross-sectional areas (CSA) were measured on 3-D echocardiography in 20 controls, in 40 patients with segmental MVP, and in 18 with global MVP. On multivariate analysis, MR severity was primarily associated with LA dilatation in segmental MVP (P<0.001), while MV annular dilatation was primarily associated with LA dilatation in global MVP (P<0.001). Although there was no regional predominance in LA dilatation in segmental MVP, inferior predominance of LA dilatation was significant in global MVP (increase in inferior, middle, and superior LA-CSA relative to mean of the controls: +220±70% vs. +171±55% vs. +137±37%, P<0.001). CONCLUSIONS: LA remodeling in segmental and global MVP is considerably different regarding its association with MR volume or MV annular dilatation and its regional predominance. While MR volume may mainly contribute to LA remodeling in segmental MVP, MV annular dilatation seems to have an important role in LA remodeling in global MVP. (Circ J 2016; 80: 2533-2540).

Immunoglobulin G4-related multiple cardiovascular lesions successfully treated with a combination of open surgery and corticosteroid therapy.

Immunoglobulin G4-related disease, a newly emerging systemic autoimmune disorder, can potentially involve the cardiovascular system. The standard treatment for immunoglobulin G4-related cardiovascular disease has not been established. We encountered a very rare case of an immunoglobulin G4-related inflammatory abdominal aortic aneurysm coexisting with a coronary artery aneurysm and periarteritis. The patient underwent surgical resection for the abdominal aortic aneurysm, followed by successful corticosteroid therapy for the coronary artery lesions. This is the first report of steroid-sensitive immunoglobulin G4-related coronary artery disease. A carefully planned treatment strategy for the multiple cardiovascular lesions was invaluable in the present case.

Impact of sarcopenia on long-term survival after cardiac surgery for end-stage renal disease patients.

BACKGROUND: The long-term mortality of end-stage renal disease (ESRD) patients is still unsatisfactory. Therefore, long-term risk assessments in ESRD patients undergoing cardiac surgery are needed. Recently, sarcopenia is major concern in cardiac surgery because of its association with poor long-term survival. However, the impact of sarcopenia on the long-term survival of ESRD patients undergoing cardiac surgery is not well understood. METHODS: Eighty-two ESRD patients who underwent elective cardiac surgery were enrolled. Sarcopenia was identified based on noncontrast abdominal computed tomography. The impact of preoperative and intraoperative factors on long-term survival was investigated. RESULTS: Forty-three patients (52%) were diagnosed with sarcopenia. The in-hospital mortality rate was 4.9%. The 5-year overall survival rate was 48%. The multivariate analyses revealed that STS score ≥ 4 (odds ratio, 6.0; confidence interval, 2.5-14.7; p < 0.01) and presence of sarcopenia (odds ratio, 2.4; confidence interval, 1.3-4.5; p = 0.03) were independent risk factors for overall survival. The 5-year survival rates of low-risk (Society of Thoracic Surgeons score of < 4) patients without sarcopenia, low-risk with sarcopenia, more than intermediate-risk (Society of Thoracic Surgeons score of ≥ 4) without sarcopenia, and more than intermediate-risk with sarcopenia groups were 80%, 51%, 50%, and 26%, respectively. CONCLUSIONS: Among the ESRD patients, the low risk without sarcopenia group showed an excellent long-term survival, in contrast to more than intermediate-risk patients with sarcopenia, who can expect poor long-term survival. Preoperative assessment of sarcopenia in addition to the surgical risk score can be useful in developing a therapeutic strategy.

Left atrial assist device to treat patients with heart failure with preserved ejection fraction: Initial in vitro study.

OBJECTIVES: Many patients with heart failure have preserved ejection fraction but also diastolic dysfunction, with no effective therapy. We are developing a new pump (left atrial assist device, LAAD) for implantation at the mitral position to pump blood from the left atrium to sufficiently fill the left ventricle. The purpose of the initial in vitro study was to demonstrate that the LAAD can reduce left atrial pressure (LAP) and increase cardiac output (CO) while maintaining arterial pulsatility and normal aortic valve function using a proof-of-concept device. METHODS: The LAAD concept was tested at 3 pump speeds on a pulsatile mock loop with a pneumatic pump that simulated the normal function of the native ventricle as well as 3 levels of diastolic heart failure (DHF 1, 2, and 3) by adjusting the diastolic drive pressure to limit diastolic filling of the ventricle. RESULTS: Without the LAAD, CO and aortic pressure (AoP) decreased dramatically from 3.8 L/min and 100 mm Hg at normal heart condition to 1.2 L/min and 35 mm Hg at DHF 3, respectively. With LAAD support, both CO and AoP recovered to normal heart values at 3200 rpm and surpassed normal heart values at 3800 rpm. Furthermore, with LAAD support, LAP recovered to almost that of the normal heart condition at 3800 rpm. CONCLUSIONS: These initial in vitro results support our hypothesis that use of the LAAD increases CO and AoP and decreases LAP under DHF conditions while maintaining arterial pulsatility and full function of the aortic valve.

The Effects of Preserving Mitral Valve Function on a Left Atrial Assist Device: An In Vitro Mock Circulation Loop Study.

We are developing a left atrial assist device (LAAD) to pump blood from the left atrium to the left ventricle for patients who have heart failure with preserved ejection fraction (HFpEF). This study aimed to assess the hemodynamics with the LAAD implanted at two different levels: the mitral valve (MV) level, after removing the MV; and the supravalvular level, preserving MV function conditions using an in vitro mock circulatory loop. Normal heart and mild, moderate, and severe diastolic heart failure conditions were simulated, and the LAAD was set at three different speeds. Without the LAAD support, cardiac output (CO) decreased from 3.7 to 1.1 L/min, aortic pressure (AoP) decreased from 100 to 33 mm Hg, and left atrial pressure (LAP) increased from 16 to 23 mm Hg as the diastolic function became impaired. With high pump support after removing the MV, CO and AoP readings were comparable with those for preserved MV function (CO reached 3.9-4.1 L/min, AoP reached more than 110 mm Hg, and LAP dropped to 16-17 mm Hg under both conditions at high pump speeds). In the mock circulatory loop, our LAAD appeared to have sufficient ability to maintain the hemodynamic status at both positions.

Left atrial assist device function at various heart rates using a mock circulation loop.

We are developing a new left atrial assist device (LAAD) for patients who have heart failure with preserved ejection fraction (HFpEF). This study aimed to assess the hemodynamic effects of the LAAD under both normal heart conditions and various diastolic heart failure (DHF) conditions using a mock circulatory loop. A continuous-flow pump that simulates LAAD, was placed between the left atrial (LA) reservoir and a pneumatic ventricle that simulated a native left ventricle on a pulsatile mock loop. Normal heart (NH) and mild, moderate, and severe DHF conditions were simulated by adjusting the diastolic drive pressures of the pneumatic ventricle. With the LAAD running at 3200 rpm, data were collected at 60, 80, and 120 bpm of the pneumatic ventricle. Cardiac output (CO), mean aortic pressure (AoP), and mean LA pressure (LAP) were compared to evaluate the LAAD performance. With LAAD support, the CO and AoP rose to a sufficient level at all heart rates and DHF conditions (CO; 3.4-3.8 L/min, AoP; 90-105 mm Hg). Each difference in the CO and the AoP among various heart rates was minuscule compared with non-pump support. The LAP decreased from 21-23 to 17-19 mm Hg in all DHF conditions (difference not significant). Furthermore, hemodynamic parameters improved for all DHF conditions, independent of heart rate. The LAAD can provide adequate flow to maintain the circulation status at various heart rates in an in vitro mock circulatory loop.

Development of a circulatory mock loop for biventricular device testing with various heart conditions.

This study aimed to evaluate a newly designed circulatory mock loop intended to model cardiac and circulatory hemodynamics for mechanical circulatory support device testing. The mock loop was built with dedicated ports suitable for attaching assist devices in various configurations. This biventricular mock loop uses two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA) driven by a dual-output driver (Thoratec Model 2600, Pleasanton, CA, USA). The drive pressures can be individually modified to simulate a healthy heart and left and/or right heart failure conditions, and variable compliance and fluid volume allow for additional customization. The loop output for a healthy heart was tested at 4.2 L/min with left and right atrial pressures of 1 and 5 mm Hg, respectively; a mean aortic pressure of 93 mm Hg; and pulmonary artery pressure of 17 mm Hg. Under conditions of left heart failure, these values were reduced to 2.1 L/min output, left atrial pressure = 28 mm Hg, right atrial pressure = 3 mm Hg, aortic pressure = 58 mm Hg, and pulmonary artery pressure = 35 mm Hg. Right heart failure resulted in the reverse balance: left atrial pressure = 0 mm Hg, right atrial pressure = 30 mm Hg, aortic pressure = 100 mm Hg, and pulmonary artery pressure = 13 mm Hg with a flow of 3.9 L/min. For biventricular heart failure, flow was decreased to 1.6 L/min, left atrial pressure = 13 mm Hg, right atrial pressure = 13 mm Hg, aortic pressure = 52 mm Hg, and pulmonary artery pressure = 18 mm Hg. This mock loop could become a reliable bench tool to simulate a range of heart failure conditions.

An advanced universal circulatory assist device for left and right ventricular support: First report of an acute in vivo implant.

Background: The Advanced ventricular assist device (Advanced VAD) is designed as a universal pump intended to prevent backflow in the event of pump stoppage, to maintain physiological pulse pressure, and to be used as both a left and right VAD. The purpose of this study was to evaluate the performance of the Advanced VAD as both a left and right VAD in an acute in vivo study in calves. Methods: The Advanced VAD was implanted through a median sternotomy in 5 healthy calves (weight, 71.4-91.2 kg) as a left VAD (n = 3) or a right VAD (n = 2). After implantation, hemodynamic parameters, including general performance and pump stoppage, were evaluated. Results: The Advanced VAD was successfully implanted as a left and right VAD without cardiopulmonary bypass. The speed range of the Advanced VAD was 2500 to 3500 rpm as a left VAD and 2000 to 2500 rpm as a right VAD. Up to 4.3 L/min was achieved for both left and right VAD configurations. To demonstrate the automatic shut-off feature, the pump was stopped without clamping the outflow graft. The outflow graft was then clamped, which produced no significant changes in the arterial pressure waveform. The pulse pressures under the left VAD configuration were 38 mm Hg, 17 mm Hg, 14 mm Hg, and 16 mm Hg at baseline, 2500 rpm, 3000 rpm, and 3500 rpm, respectively. Conclusions: This acute in vivo study demonstrated the pump performance, anatomical fitting as both left VAD and right VAD, and regurgitant flow shut-off feature of the Advanced VAD.

First In Vivo Experience With Biventricular Circulatory Assistance Using a Single Continuous Flow Pump.

Biventricular assist device (BVAD) implantation is the treatment of choice in patients with severe biventricular heart failure and cardiogenic shock. Our team has developed a miniaturized continuous flow, double-ended centrifugal pump intended for total artificial heart implant (CFTAH). The purpose of this initial in vivo study was to demonstrate that the scaled-down CFTAH (P-CFTAH) can be appropriate for BVAD support. The P-CFTAH was implanted in 4 acute lambs (average weight, 41.5 ± 2.8 kg) through a median sternotomy. The cannulation was performed through the left and right atria, and cannulae length adjustment was performed for atrial and ventricular cannulation. The BVAD system was tested at 3 pump speeds (3000, 4500, and 6000 rpm). The BVAD performed very well for both atrial and ventricular cannulation within the 3000-6000 rpm range. Stable hemodynamics were maintained after implantation of the P-CFTAH. The self-regulating performance of the system in vivo was demonstrated by the left (LAP) and right (RAP) pressure difference (LAP-RAP) falling predominantly within the range of -5 to 10 mm Hg with variation, in addition to in vitro assessment of left and right heart failure conditions. Left and right pump flows and total flow increased as the BVAD speed was increased. This initial in vivo testing of the BVAD system demonstrated satisfactory device performance and self-regulation for biventricular heart failure support over a wide range of conditions. The BVAD system keeps the atrial pressure difference within bounds and maintains acceptable cardiac output over a wide range of hemodynamic conditions.

Use of a Virtual Mock Loop model to evaluate a new left ventricular assist device for transapical insertion.

We are developing a novel type of miniaturized left ventricular assist device that is configured for transapical insertion. The aim of this study was to assess the performance and function of a new pump by using a Virtual Mock Loop system for device characterization and mapping. The results, such as pressure-flow performance curves, from pump testing in a physical mock circulatory loop were used to analyze its function as a left ventricular assist device. The Virtual Mock Loop system was programmed to mimic the normal heart condition, systolic heart failure, diastolic heart failure, and both systolic and diastolic heart failure, and to provide hemodynamic pressure values before and after the activation of several left ventricular assist device pump speeds (12,000, 14,000, and 16,000 r/min). With pump support, systemic flow and mean aortic pressure increased, and mean left atrial pressure and pulmonary artery pressure decreased for all heart conditions. Regarding high pump-speed support, the systemic flow, aortic pressure, left atrial pressure, and pulmonary artery pressure returned to the level of the normal heart condition. Based on the test results from the Virtual Mock Loop system, the new left ventricular assist device for transapical insertion may be able to ease the symptoms of patients with various types of heart failure. The Virtual Mock Loop system could be helpful to assess pump performance before in vitro bench testing.

Update on the management and associated challenges of adult patients treated with veno-arterial extracorporeal membrane oxygenation.

INTRODUCTION: Currently, veno-arterial extracorporeal membrane oxygenation (VA ECMO) represents a valuable treatment option for patients presenting with severe cardiogenic shock. Although the overall usage of VA ECMO in experienced centers is expanding, some management aspects remain challenging, with no consensus among centers on well-defined assessment criteria, duration, and, particularly, weaning strategies. AREAS COVERED: This article aims to provide a review and evaluation of strategies reported in the literature to wean patients from VA ECMO, with a special emphasis on weaning protocols. A selected successful weaning protocol and rate of removal of adult patients from VA ECMO from recent reports will be also discussed. EXPERT COMMENTARY: To improve patient outcome, it is essential to remove patients from VA ECMO without weaning failure. Furthermore, the accurate evaluation of the patient's condition must be principal. However, as technology advances, the strategy of weaning patients from VA ECMO or drug therapies is changing, and we must periodically update our knowledge and use of VA ECMO.

Timing on echocardiography and blood laboratory test is important for future outcome association in hospitalized heart failure patients.

BACKGROUND: We investigated whether both echocardiography and blood examination parameters obtained before discharge are more closely associated with adverse events than those obtained upon admission in hospitalized heart failure (HF) patients. METHODS: We retrospectively selected 267 hospitalized HF patients who underwent comprehensive transthoracic echocardiography (TTE) within 2 days of admission (n=223) and/or within 7 days of discharge (n=157). Blood test results were also collected at the same time window. Patients were assigned into HF with reduced ejection fraction (HFrEF) and HF with preserved EF (HFpEF). RESULTS: During a median follow-up of 12.6 months, 60 of 223 patients with admission TTE and 39 of 157 patients with pre-discharge TTE had major adverse cardiac events (MACEs) after discharge. On admission, no echocardiography parameters, but uric acid, blood urea nitrogen (BUN), creatinine, and estimated glomerular filtration rate (eGFR) were associated with MACEs in HFpEF (n=45). In HFrEF (n=178), vena contracta, s', BUN, eGFR, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with MACEs. Before discharge, BNP, NT-proBNP, and E/e' were significantly associated with MACEs in HFpEF (n=41). In HFrEF (n=116), several echocardiography parameters and blood tests were significantly associated with MACEs. CONCLUSIONS: Optimal examination timing for prognostication is different between echocardiography but not for blood tests. TTE before discharge provides more information in both HF phenotypes, while blood tests play a role both upon admission and before discharge. Therefore, a pre-discharge TTE was recommended in patients admitted for HF.

Impact of image quality on reliability of the measurements of left ventricular systolic function and global longitudinal strain in 2D echocardiography.

BACKGROUND: Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) play important roles in diagnosis and management of cardiac diseases. However, the issue of the accuracy and reliability of LVEF and GLS remains to be solved. Image quality is one of the most important factors affecting measurement variability. The aim of this study was to investigate whether improved image quality could reduce observer variability. METHODS: Two sets of three apical images were acquired using relatively old- and new-generation ultrasound imaging systems (Vivid 7 and Vivid E95) in 308 subjects. Image quality was assessed by endocardial border delineation index (EBDI) using a 3-point scoring system. Three observers measured the LVEF and GLS, and these values and inter-observer variability were investigated. RESULTS: Image quality was significantly better with Vivid E95 (EBDI: 26.8 ± 5.9) than that with Vivid 7 (22.8 ± 6.3, P < 0.0001). Regarding the inter-observer variability of LVEF, the r-value, bias, 95% limit of agreement and intra-class correlation coefficient for Vivid 7 were comparable to those for Vivid E95. The % variabilities were significantly lower for Vivid E95 (5.3-6.5%) than those for Vivid 7 (6.5-7.5%). Regarding GLS, all observer variability parameters were better for Vivid E95 than for Vivid 7. Improvements in image quality yielded benefits to both LVEF and GLS measurement reliability. Multivariate analysis showed that image quality was indeed an important factor of observer variability in the measurement of LVEF and GLS. CONCLUSIONS: The new-generation ultrasound imaging system offers improved image quality and reduces inter-observer variability in the measurement of LVEF and GLS.

Strain Imaging with a Bull's-Eye Map for Detecting Significant Coronary Stenosis during Dobutamine Stress Echocardiography.

BACKGROUND: Accurate visual assessment of wall motion during dobutamine stress echocardiography (DSE) requires expertise; strain stress echocardiography thus has potential for the objective and reliable evaluation of stress-induced wall motion abnormalities. The aim of this study was to test the hypothesis that strain imaging also requires expertise. Diagnostic accuracy for significant coronary artery disease was compared between visual and strain analysis with a bull's-eye map, and the effect of expertise on readers' accuracy during DSE was determined. METHODS: Thirty-seven patients who underwent both DSE and coronary angiography within 6 months were retrospectively selected. Three experts and two fellows performed visual and two-dimensional speckle-tracking analysis using vendor-dependent (GE) software in three apical views. A bull's-eye map of longitudinal strain and a postsystolic shortening map were generated at baseline and peak stress. Significant coronary stenosis was defined as a >1% reduction in longitudinal strain with an increase in postsystolic shortening of at least two contiguous segments in the specific coronary artery territory at peak stress compared with baseline. RESULTS: Twenty-five patients had significant coronary artery disease (>70% stenosis on coronary angiography), including 17 with left anterior descending coronary artery stenosis and 19 with non-left anterior descending coronary artery stenosis. Overall, strain imaging provided no additional benefit over visual analysis in detecting significant stenosis per patient and per vessel among experts and fellows. Strain analysis by the fellows had significantly lower specificity and accuracy compared with the experts. CONCLUSIONS: Expertise affects strain evaluation for detecting significant coronary artery disease during DSE.

Prognostic Value of Right Ventricular Ejection Fraction Assessed by Transthoracic 3D Echocardiography.

BACKGROUND: Cardiac magnetic resonance is the gold standard for the evaluation of right ventricular (RV) volumes, but it is impractical to perform in every patient. Although reference values of RV volumes and RV ejection fraction by 3D transthoracic echocardiography (3DTTE) have been established, their prognostic values have not been elucidated yet. We hypothesized that RV ejection fraction measured by 3DTTE (3DRVEF) predicts future cardiovascular events. METHODS AND RESULTS: In protocol 1, we determined the accuracy of RV volumes and RV ejection fraction measurements by 3DTTE against cardiac magnetic resonance in 60 subjects. In protocol 2, 3DRVEF was measured in 446 patients with various cardiovascular diseases. Study subjects were followed up to record cardiac death and major adverse cardiovascular events. In protocol 1, 3DTTE-determined RV end-diastolic volume, end-systolic volume, and RV ejection fraction had good correlations to those by cardiac magnetic resonance (r=0.74-0.90). In protocol 2, 38 cardiac deaths and 88 major adverse cardiovascular events occurred during a median follow-up of 4.1 years. Univariable Cox proportional analysis revealed that 3DRVEF was associated with both cardiac death (P<0.0001) and major adverse cardiovascular event (P<0.0001). 3DRVEF remained as an independent predictor for cardiac death (P<0.0001) and major adverse cardiovascular event (P<0.0001) even in a stepwise multivariable Cox proportional hazard analysis. Classification and regression-tree analysis demonstrated that 3DRVEF played an important role for risk stratification. CONCLUSIONS: 3DTTE-determined RV ejection fraction was independently associated with cardiac outcomes in patients with diverse backgrounds. 3DRVEF offered incremental value over clinical risk factors and the other echocardiographic parameters including left ventricular systolic and diastolic function for predicting future adverse outcome.

Feasibility of One-Beat Real-Time Full-Volume Three-Dimensional Echocardiography for Assessing Left Ventricular Volumes and Deformation Parameters.

BACKGROUND: Real-time three-dimensional echocardiographic (3DE) imaging usually requires multibeat acquisition to maintain high temporal and spatial resolution for full-volume data sets. However, this procedure generates stitch artifacts in patients with irregular heartbeats; thus, one-beat acquisition might be useful. The aim of this study was to compare the efficacy of using new-generation one-beat full-volume acquisition for measuring left ventricular (LV) mechanical parameters with that of four-beat acquisition. METHODS: In protocol 1, 34 patients who had undergone both cardiac magnetic resonance and 3DE imaging on the same day were prospectively enrolled. In protocol 2, 115 patients in sinus rhythm who had undergone 3DE examinations were retrospectively enrolled. LV volume, ejection faction, and global strain were measured using one-beat and four-beat 3DE data sets. In protocol 3, 26 patients with atrial fibrillation who had acquisition of consecutive one-beat full-volume data sets were retrospectively enrolled, and it was determined whether the LV parameters in the index beat were correlated with corresponding average values obtained from multiple one-beat acquisitions. RESULTS: In protocol 1, the correlations between LV volumes and LV ejection fraction between cardiac magnetic resonance and 3DE imaging with one-beat acquisition were excellent (r = 0.91-0.93). In protocol 2, correlations were also excellent (r = 0.94-0.99), and there were no significant differences in volume rate, LV volumes, LV ejection fraction, and global strain parameters between one-beat and four-beat acquisition data sets. In protocol 3, correlations were excellent (r = 0.94-0.99) between LV parameters from the index beat and corresponding average values. CONCLUSIONS: Three-dimensional echocardiographic full-volume data sets with one-beat acquisition not only maintained volume rate but also provided LV mechanical parameter values similar to those obtained using multibeat acquisition. Using one-beat acquisition for patients with atrial fibrillation expands its clinical applicability.