Effect of Low-Sodium versus Conventional Sodium Dialysate on Left Ventricular Mass in Home and Self-Care Satellite Facility Hemodialysis Patients: A Randomized Clinical Trial.

BACKGROUND: Fluid overload in patients undergoing hemodialysis contributes to cardiovascular morbidity and mortality. There is a global trend to lower dialysate sodium with the goal of reducing fluid overload. METHODS: To investigate whether lower dialysate sodium during hemodialysis reduces left ventricular mass, we conducted a randomized trial in which patients received either low-sodium dialysate (135 mM) or conventional dialysate (140 mM) for 12 months. We included participants who were aged >18 years old, had a predialysis serum sodium ≥135 mM, and were receiving hemodialysis at home or a self-care satellite facility. Exclusion criteria included hemodialysis frequency >3.5 times per week and use of sodium profiling or hemodiafiltration. The main outcome was left ventricular mass index by cardiac magnetic resonance imaging. RESULTS: The 99 participants had a median age of 51 years old; 67 were men, 31 had diabetes mellitus, and 59 had left ventricular hypertrophy. Over 12 months of follow-up, relative to control, a dialysate sodium concentration of 135 mmol/L did not change the left ventricular mass index, despite significant reductions at 6 and 12 months in interdialytic weight gain, in extracellular fluid volume, and in plasma B-type natriuretic peptide concentration (ratio of intervention to control). The intervention increased intradialytic hypotension (odds ratio [OR], 7.5; 95% confidence interval [95% CI], 1.1 to 49.8 at 6 months and OR, 3.6; 95% CI, 0.5 to 28.8 at 12 months). Five participants in the intervention arm could not complete the trial because of hypotension. We found no effect on health-related quality of life measures, perceived thirst or xerostomia, or dietary sodium intake. CONCLUSIONS: Dialysate sodium of 135 mmol/L did not reduce left ventricular mass relative to control, despite improving fluid status. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: The Australian New Zealand Clinical Trials Registry, ACTRN12611000975998.

Clinical Characteristics and Outcomes of Patients with Amphetamine-Associated Cardiomyopathy in South Auckland, New Zealand.

BACKGROUND: Amphetamine-associated cardiomyopathy (AAC) is becoming an increasingly recognised entity. The characteristics and outcomes of these patients are poorly understood. METHODS: Thirty patients admitted with heart failure and echocardiographic evidence of cardiomyopathy between 2005 and 2014 and who had a documented history of amphetamine abuse that was considered an important factor in the causation of their cardiomyopathy were retrospectively identified. RESULTS: Mean age at presentation was 40±10 years with a male predominance (n=25, 83%). The majority were of indigenous Maori ethnicity. At presentation, four patients were in cardiogenic shock. Five patients required intensive care unit (ICU) admission for inotropic support and mechanical ventilation. Fifteen had severe left ventricular (LV) dilation (mean LV end-diastolic dimension 6.8±1.0cm) and all patients had severe LV dysfunction (mean LV ejection fraction 22±8%). Despite optimal heart failure therapy, LV size remained significantly dilated with minimal improvement in LV function. During median follow-up of 18 months, five patients died from end-stage heart failure and 17 had at least one readmission with decompensated heart failure. CONCLUSION: Amphetamine-associated cardiomyopathy was seen predominantly in young indigenous Maori men. They presented with severe cardiomyopathy, often requiring ICU admission. Severe LV dilation and significant LV dysfunction persisted despite treatment and mortality was high.

Effect of protocol choice on phase contrast cardiac magnetic resonance flow measurement in the ascending aorta: breath-hold and non-breath-hold.

Flow assessment with phase contrast magnetic resonance imaging (PC-MRI) protocols is an important component of a comprehensive cardiovascular MR (CMR) assessment. Breath-hold (BH) and non-breath-hold (NBH) PC-MRI protocols are widely available for this imaging modality. Because flow in the great vessels is known to vary with the respiratory cycle, we hypothesized that these 2 approaches might yield different results in the clinical assessment of forward and regurgitant flow in the ascending aorta. Further, given renewed awareness of the possible effect of velocity offsets in PC-MRI, we also sought to evaluate the impact of BH and NBH protocols on this potential source of error. A prospective observational study was performed in 55 consecutive patients referred for clinical CMR of the thoracic aorta. Both BH and NBH protocols were performed at the sinotubular junction and at the mid ascending aorta. Ten additional patients underwent repeated scanning at the mid ascending aorta with both BH and NBH protocols so that protocol variability could be assessed. Finally, ten patients were scanned with both BH and NBH protocols, and phantoms were then imaged with identical imaging parameters so that offset errors associated with each protocol could be evaluated. Forward flow was generally greater with the NBH protocol than with the BH protocol (mean values 102.1 mL vs. 97.9 mL; P = 0.0004). The Bland-Altman limits of agreement were quite wide for all indices (e.g, forward flow, -26.7 mL, +18.2 mL), which suggests that results from BH and NBH protocols cannot be interchanged with confidence. Estimated phase offset errors were similar for both protocols and were generally within acceptable ranges at the mid ascending level, with slightly higher values observed at the sinotubular junction for the BH technique. We observed differences in flow values with BH and NBH protocols for PC-MRI. This finding is relevant to patients imaged serially for the evaluation of cardiac output or valve (aortic or mitral) insufficiency, for whom adherence to one PC-MRI breathing protocol is likely most effective.

Role of Transesophageal Echocardiography Compared to Computed Tomography in Evaluation of Pulmonary Vein Ablation for Atrial Fibrillation (ROTEA study).

BACKGROUND: Computed tomography (CT) is the gold standard for assessing pulmonary vein (PV) anatomy and stenosis after ablation for atrial fibrillation (AF), but radiation exposure can be a concern. Transesophageal echocardiography (TEE) provides anatomic and functional assessment of the PVs, although no study has prospectively compared findings on TEE with those on CT. METHODS: The Role of Transesophageal Echocardiography Compared to Computed Tomography in Evaluation of Pulmonary Vein Ablation for Atrial Fibrillation (ROTEA) study was a prospective, single-blinded observational study of patients with paroxysmal or persistent AF undergoing ablation. TEE and CT were performed immediately before and 3 months after AF ablation. The study included 43 patients (84% men; mean age, 56 ± 11 years). RESULTS: In the preprocedural study, TEE identified 98% of PVs with adequate Doppler measurements obtained. After ablation, no moderate or severe PV stenosis was detected on CT, and a 30% to 50% reduction in luminal diameter was seen in 5% of studied veins. Functional PV stenosis by pulsed-wave Doppler was seen in two veins on TEE. PV diameters decreased after ablation by 0.20 ± 0.03 and 0.22 ± 0.03 cm as measured by CT and TEE, respectively (P < .001). However, TEE underestimated PV ostial dimensions compared with CT, especially for the inferior PVs. Severe spontaneous echo contrast and low left atrial appendage emptying velocities, were identified in 10% of patients in sinus rhythm after ablation. CONCLUSIONS: In the ROTEA study, TEE was feasible in assessing PVs before and after ablation, providing both anatomic and functional information that complemented CT. PV ostial dimensions after ablation can be monitored using either modality, although TEE underestimates PV dimensions, especially for the inferior veins.

Comparison of severity of aortic regurgitation by cardiovascular magnetic resonance versus transthoracic echocardiography.

Transthoracic echocardiography is the current standard for assessing aortic regurgitation (AR). AR severity can also be evaluated by flow measurement in the ascending aorta using cardiac magnetic resonance (CMR); however, the optimal site for flow measurement and the regurgitant fraction (RF) severity grading criteria that best compares with the transthoracic echocardiographic assessment of AR are not clear. The present study aimed to determine the optimal site and RF grading criteria for AR severity using phase-contrast flow measurements and CMR. A prospective observational study was performed of 107 consecutive patients who were undergoing CMR of the thoracic aorta. Using CMR, the AR severity and aortic dimensions were measured at 3 levels in the aorta (the sinotubular junction, mid-ascending aorta, and distal ascending aorta). The results were compared to the transthoracic echocardiographic grade of AR severity using multiple qualitative and quantitative criteria (grade 0, none; I+, mild; II+, mild to moderate; III+, moderate to severe; and IV+, severe). The mean RF values were significantly greater at the sinotubular junction than at the distal ascending aorta (13 ± 13.3% vs 9.4 ± 12.6%, respectively; p <0.001). The RF values that best defined AR severity using phase-contrast CMR were as follows: grade 0 to I+, <8%; grade II+, 8% to 19%; grade III+, 20 to 29%; and grade IV+, 30%) at the sinotubular or mid-ascending aorta. In conclusion, the quantitative RF values of AR severity using phase-contrast flow are best assessed in the proximal ascending aorta and differ from recognized quantitative echocardiographic criteria.

Cardiac MR assessment of aortic regurgitation: holodiastolic flow reversal in the descending aorta helps stratify severity.

PURPOSE: To assess the utility of holodiastolic flow reversal (HDR) in the descending aorta on velocity-encoded cardiac magnetic resonance (MR) images in the stratification of aortic regurgitation (AR) severity. MATERIALS AND METHODS: This study was approved by the institutional review board, with waiver of informed consent. A total of 80 patients (overall mean age, 49 years ± 18 [standard deviation]; 22 women and 58 men) with clinical indication for cardiac MR imaging of the aorta were analyzed retrospectively. Velocity-encoded MR imaging was used to quantify AR and assess for HDR at the level of the middescending aorta. These indexes were compared with a qualitative integrated echocardiographic evaluation of AR severity. Sensitivity and specificity for HDR in the prediction of substantial AR were determined, and logistic regression analysis (with associated odds ratios and C statistics) was performed, with HDR and regurgitant fraction as independent predictors. An additional 42 patients (overall mean age, 48 years ± 21; 12 female and 30 male) were then prospectively evaluated in similar fashion to evaluate a decision model derived from analysis of the first group. RESULTS: HDR predicted severe AR (echo grade, 4) with high sensitivity (100%) and specificity (93%). HDR was highly specific (100%) but had lower sensitivity (61%) for moderate to severe AR (echo grade, 3-4). Integration of HDR and direct AR quantification into a combined stratification model based on analysis of the primary group showed good predictive results in the validation group, with a C statistic of 0.94 for moderate to severe AR and 0.93 for severe AR. CONCLUSION: HDR in the middescending thoracic aorta observed at cardiac MR is indicative of severe AR and can be used in conjunction with quantified regurgitant values obtained from velocity-encoded MR imaging to stratify AR severity.

Role of the CHADS2 score in the evaluation of thromboembolic risk in patients with atrial fibrillation undergoing transesophageal echocardiography before pulmonary vein isolation.

OBJECTIVES: The goals of this study were to determine: 1) if low-risk patients assessed by a CHADS(2) score, a clinical scoring system quantifying a risk of stroke in patients with atrial fibrillation (AF), require a routine screening transesophageal echocardiogram (TEE) before pulmonary vein isolation (PVI); and 2) the relationship of a CHADS(2) score with left atrial (LA)/left atrial appendage (LAA) spontaneous echo contrast, sludge, and thrombus. BACKGROUND: There is no clear consensus of whether a screening TEE before catheter ablation of AF should be performed in every patient. METHODS: Initial TEEs for pre-PVI of 1,058 AF patients (age 57 +/- 11 years, 80% men) were reviewed and compared with a CHADS(2) score. RESULTS: CHADS(2) scores of 0, 1, 2, 3, 4, 5, and 6 were present in 47%, 33%, 14%, 5%, 1%, 0.3%, and 0% of patients, respectively. The prevalence of LA/LAA thrombus, sludge, and spontaneous echo contrast were present in 0.6%, 1.5%, and 35%. The prevalence of LA/LAA thrombus/sludge increased with ascending CHADS(2) score (scores 0 [0%], 1 [2%], 2 [5%], 3 [9%], and 4 to 6 [11%], p < 0.01). No patient with a CHADS(2) score of 0 had LA/LAA sludge/thrombus. In a multivariate model, history of congestive heart failure and left ventricular ejection fraction <35% were significantly associated with sludge/thrombus. CONCLUSIONS: The prevalence of LA/LAA sludge/thrombus in patients with AF undergoing a pre-PVI screening TEE is very low (<2%) and increases significantly with higher CHADS(2) scores. This suggests that a screening TEE before PVI should be performed in patients with a CHADS(2) score of >or=1, and in patients with a CHADS(2) score of 0 when the AF is persistent and therapeutic anticoagulation has not been maintained for 4 weeks before the procedure.

Aortic valve stenotic area calculation from phase contrast cardiovascular magnetic resonance: the importance of short echo time.

BACKGROUND: Cardiovascular magnetic resonance (CMR) can potentially quantify aortic valve area (AVA) in aortic stenosis (AS) using a single-slice phase contrast (PC) acquisition at valve level: AVA = aortic flow/aortic velocity-time integral (VTI). However, CMR has been shown to underestimate aortic flow in turbulent high velocity jets, due to intra-voxel dephasing. This study investigated the effect of decreasing intra-voxel dephasing by reducing the echo time (TE) on AVA estimates in patients with AS. METHOD: 15 patients with moderate or severe AS, were studied with three different TEs (2.8 ms/2.0 ms/1.5 ms), in the main pulmonary artery (MPA), left ventricular outflow tract (LVOT) and 0 cm/1 cm/2.5 cm above the aortic valve (AoV). PC estimates of stroke volume (SV) were compared with CMR left ventricular SV measurements and PC peak velocity, VTI and AVA were compared with Doppler echocardiography. CMR estimates of AVA obtained by direct planimetry from cine acquisitions were also compared with the echoAVA. RESULTS: With a TE of 2.8 ms, the mean PC SV was similar to the ventricular SV at the MPA, LVOT and AoV0 cm (by Bland-Altman analysis bias +/- 1.96 SD, 1.3 +/- 20.2 mL/-6.8 +/- 21.9 mL/6.5 +/- 50.7 mL respectively), but was significantly lower at AoV1 and AoV2.5 (-29.3 +/- 31.2 mL/-21.1 +/- 35.7 mL). PC peak velocity and VTI underestimated Doppler echo estimates by approximately 10% with only moderate agreement. Shortening the TE from 2.8 to 1.5 msec improved the agreement between ventricular SV and PC SV at AoV0 cm (6.5 +/- 50.7 mL vs 1.5 +/- 37.9 mL respectively) but did not satisfactorily improve the PC SV estimate at AoV1 cm and AoV2.5 cm. Agreement of CMR AVA with echoAVA was improved at TE 1.5 ms (0.00 +/- 0.39 cm2) versus TE 2.8 (0.11 +/- 0.81 cm2). The CMR method which agreed best with echoAVA was direct planimetry (-0.03 cm2 +/- 0.24 cm2). CONCLUSION: Agreement of CMR AVA at the aortic valve level with echo AVA improves with a reduced TE of 1.5 ms. However, flow measurements in the aorta (AoV 1 and 2.5) are underestimated and 95% limits of agreement remain large. Further improvements or novel, more robust techniques are needed in the CMR PC technique in the assessment of AS severity in patients with moderate to severe aortic stenosis.

Modern evaluation of left ventricular diastolic function using Doppler echocardiography.

The evaluation of left ventricular (LV) diastolic function is an essential component of the echocardiographic examination for dyspneic patients with impaired or preserved LV systolic function. Doppler echocardiography in combination with two-dimensional echocardiographic findings can assist the diagnosis of underlying cardiac dysfunction, give an estimate of LV filling pressures, guide heart failure treatment, and provide important prognostic information. This article reviews the essentials of modern Doppler assessment of diastolic function and highlights recent updates, areas of controversy, and future applications.

Managing catheter ablation for atrial fibrillation: the role of echocardiography.

Atrial fibrillation (AF) is a common arrhythmia associated with the serious clinical consequences of systemic thrombo-embolism and heart failure. Catheter ablation for AF is an evolving treatment option for patients with drug-refractory paroxysmal and persistent AF. The ablation procedure relies on precise knowledge of the left atrium, left atrial appendage, and pulmonary venous anatomy and function. Echocardiography is an integral component of multiple imaging modalities which contribute to its success. Both transoesophageal echocardiography and transthoracic echocardiography provide essential anatomical and functional information to guide all aspects of management. This article reviews the role of echocardigraphy in AF ablation, from appropriate patient selection and pre-procedural screening, to evaluating complications and determining the need for long-term anticoagulation.

Safety of ultrasound contrast agents in stress echocardiography.

Definity and Optison are perflutren-based ultrasound contrast agents used in echocardiography. United States Food and Drug Administration warnings regarding serious cardiopulmonary reactions and death after Definity administration highlighted the limited safety data in patients who undergo contrast stress echocardiography. From 1998 and 2007, 2,022 patients underwent dobutamine stress echocardiography and 2,764 underwent exercise stress echocardiography with contrast at the Cleveland Clinic. The echocardiographic database, patient records, and the Social Security Death Index were reviewed for the timing and cause of death, severe adverse events, arrhythmias, and symptoms. Complication rates for contrast dobutamine stress echocardiography and exercise stress echocardiography were compared with those in a control group of 5,012 patients matched for test year and type who did not receive contrast. Ninety-five percent of studies were performed in outpatients. There were no differences in the rates of severe adverse events (0.19% vs 0.17%, p = 0.7), death within 24 hours (0% vs 0.04%, p = 0.1), cardiac arrest (0.04% vs 0.04%, p = 0.96), and sustained ventricular tachycardia (0.2% vs 0.1%, p = 0.32) between patients receiving and not receiving intravenous contrast, respectively. In conclusion, severe adverse reactions to intravenous contrast agents during stress echocardiography are uncommon. Contrast use does not add to the baseline risk for severe adverse events in patients who undergo stress echocardiography.

Mapping of mitral regurgitant defects by cardiovascular magnetic resonance in moderate or severe mitral regurgitation secondary to mitral valve prolapse.

PURPOSE: In mitral valve prolapse, determining whether the valve is suitable for surgical repair depends on the location and mechanism of regurgitation. We assessed whether cardiovascular magnetic resonance (CMR) could accurately identify prolapsing or flail mitral valve leaflets and regurgitant jet direction in patients with known moderate or severe mitral regurgitation. METHODS: CMR of the mitral valve was compared with trans-thoracic echocardiography (TTE) in 27 patients with chronic moderate to severe mitral regurgitation due to mitral valve prolapse. Contiguous long-axis high temporal resolution CMR cines perpendicular to the valve commissures were obtained across the mitral valve from the medial to lateral annulus. This technique allowed systematic valve inspection and mapping of leaflet prolapse using a 6 segment model. CMR mapping was compared with trans-oesophageal echocardiography (TOE) or surgical inspection in 10 patients. RESULTS: CMR and TTE agreed on the presence/absence of leaflet abnormality in 53 of 54 (98%) leaflets. Prolapse or flail was seen in 36 of 54 mitral valve leaflets examined on TTE. CMR and TTE agreed on the discrimination of prolapse from flail in 33 of 36 (92%) leaflets and on the predominant regurgitant jet direction in 26 of the 27 (96%) patients. In the 10 patients with TOE or surgical operative findings available, CMR correctly classified presence/absence of segmental abnormality in 49 of 60 (82%) leaflet segments. CONCLUSION: Systematic mitral valve assessment using a simple protocol is feasible and could easily be incorporated into CMR studies in patients with mitral regurgitation due to mitral valve prolapse.

ExTRACT-TIMI 25 trial: clarifying the role of enoxaparin in patients with ST-elevation myocardial infarction receiving fibrinolysis.

Pharmacologic reperfusion remains the most common treatment strategy for ST-elevation myocardial infarction (STEMI) worldwide. Unfractionated heparin (UFH) is the established adjunctive antithrombotic agent used with fibrinolytic agents. Low-molecular-weight heparins (LMWHs) are a potential alternative to UFH, but have not been evaluated in large cohorts of patients. The Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment (ExTRACT)-Thrombolysis in Myocardial Infarction (TIMI) 25 was a double-blind, double-dummy randomized controlled trial, of 20,479 patients, which demonstrated the superiority of enoxaparin over UFH in reducing death or nonfatal myocardial infarction (MI) at 30 days, with an increase in major bleeding. The composite of death, nonfatal MI and nonfatal intracranial hemorrhage, was reduced with enoxaparin. Elderly patients (> or = 75 years of age) received a novel enoxaparin dosing regimen and when compared with UFH, benefited from a lower relative bleeding risk than younger patients without compromising efficacy in preventing death or MI. Intracranial hemorrhage rates were similar. The net clinical benefit of enoxaparin over UFH was maintained regardless of whether patients were on clopidogrel or not, or whether percutaneous coronary intervention was performed. Enoxaparin is an appropriate choice for adjunctive therapy with fibrinolysis in patients with STEMI.

Reliability of echocardiographic indices of dyssynchrony.

BACKGROUND: Echocardiographic indices of dyssynchrony are increasingly used to select candidates for cardiac resynchronization therapy. For widespread screening of heart failure patients, such variables need to be comparable when evaluated by different operators using different equipment. OBJECTIVE AND METHODS: To evaluate the reproducibility and obtainability of echocardiographic indices of mechanical dyssynchrony, we studied 40 subjects stratified according to QRS morphology and systolic function. Two echocardiograms were performed on each patient by different sonographers on different machines and each study was analyzed by two observers. RESULTS: All blood-pool and tissue Doppler indices of dyssynchrony were obtainable in over 97% of cases. Blood-pool Doppler measures were the most reproducible indices of intraventricular dyssynchrony (aortic ejection delay) and interventricular dyssynchrony (aortopulmonary difference in ejection delay). For annular tissue Doppler delays, the time to peak velocity was consistently more reproducible than the time to velocity onset. CONCLUSION: Differences in the reliability of echocardiographic indices may affect their suitability as screening tests for dyssynchrony.