Anish Kirpalani

Comparative Assessment of 2-Dimensional Echocardiography vs Cardiac Magnetic Resonance Imaging in Measuring Left Ventricular Mass in Patients With and Without End-Stage Renal Disease

BACKGROUND While echocardiography (ECHO)-measured left ventricular mass (LVM) predicts adverse cardiovascular events that are common in hemodialysis (HD) recipients, cardiac magnetic resonance imaging (CMR) is now considered the reference standard for determination of LVM. This study aimed to evaluate concordance between LVM measurements across ECHO and CMR among chronic HD recipients and matched controls. METHODS A single-centre, cross-sectional study of 41 chronic HD patients and 41 matched controls with normal kidney function was performed to compare LVM measurements and left ventricular hypertrophy (LVH) designation by ECHO and CMR. RESULTS In both groups, ECHO, compared with CMR, overestimated LVM. Bland-Altman analysis demonstrated wider agreement limits in LVM measurements by ECHO and CMR in the chronic HD group (mean difference, 60.8 g; limits -23 g to 144.6 g) than in the group with normal renal function (mean difference, 51.4 g; limits -10.5 g to 113.3 g). LVH prevalence by ECHO and CMR in the chronic HD group was 37.5% and 22.5%, respectively, while 17.5% and 12.5% had LVH by ECHO and CMR, respectively, in the normal kidney function group. Intermodality agreement in the designation of LVH was modest in the chronic HD patients (κ = 0.42, P = 0.005) but strong (κ = 0.81, P < 0.001) in the patients with preserved kidney function. Agreement was strong in assessing LVH by ECHO and CMR only in those with normal kidney function. CONCLUSIONS Our results suggest that the limitations of LVM measurement by ECHO may be more pronounced in patients receiving HD, and provide additional support for the use of CMR in research and clinical practice when rigourous assessment of LVM is essential.

Pancreas volume measurement in patients with Type 2 diabetes using magnetic resonance imaging-based planimetry

BACKGROUND/OBJECTIVES To compare pancreas volume (PV) measurement using MRI-based planimetry in patients with Type 2 diabetes mellitus (DM) to PV in normoglycemic individuals. METHODS Our institutional review board granted approval of this retrospective study with waiver of informed consent. We searched 2296 consecutive abdominal MRI studies performed at our hospital on patients with no pancreas pathology between September 1, 2010 and February 28, 2013, for those who also had a fasting plasma glucose and/or hemoglobin A1C within six months of the MRI examination. For those patients who met biochemical criteria for DM, we used medication and clinical records to confirm that 32 of these patients had Type 2 DM. The pancreas contours of 32 Type 2 diabetics and 50 normoglycemic individuals were then traced on non-gadolinium T1-weighted 3D fat suppressed gradient echo images by a radiologist trained in abdominal MRI to calculate PV. PV index (PVI) was calculated as PV/weight to adjust PV for each patients weight. PVs and PVIs in both cohorts were compared using t-tests and regression models correcting for weight, age and gender. RESULTS Patients with Type 2 DM had significantly lower PVs than normoglycemic individuals (72.7 ± 20.7 cm(3) versus 89.6 ± 22.7 cm(3), p < 0.001), and significantly lower PVIs (1.0 ± 0.3 cm(3)/kg versus 1.3 ± 0.3 cm(3)/kg, p < 0.001). Using regression models, we found that given the same age, weight and gender, the PV in a patient with Type 2 DM was 17.9 mL (20%) lower compared to a normoglycemic individual (p < 0.001). CONCLUSION PV is reduced in Type 2 DM compared to normoglycemic individuals and can be measured using MRI without contrast injection.

Relationship between different blood pressure measurements and left ventricular mass by cardiac magnetic resonance imaging in end-stage renal disease.

Hypertension is prevalent in patients with end-stage renal disease and is strongly associated with left ventricular hypertrophy (LVH), an independent predictor of cardiovascular mortality. Blood pressure (BP) monitoring in hemodialysis patients may be unreliable because of its lability and variability. We compared different methods of BP measurement and their relationship with LVH on cardiac magnetic resonance imaging. Sixty patients undergoing chronic hemodialysis at a single dialysis center had BP recorded at each dialysis session over 12 weeks: pre-dialysis, initial dialysis, nadir during dialysis, and post-dialysis. Forty-five of these patients also underwent 44-hour inter-dialytic ambulatory BP monitoring. Left ventricular mass index (LVMI) was measured using cardiac magnetic resonance imaging and the presence of LVH was ascertained. Receiver operator characteristic curves were generated for each BP measurement for predicting LVH. The mean LVMI was 68 g/m(2) (SD = 15 g/m(2)); 13/60 patients (22%) had LVH. Mean arterial pressure measured shortly after initiation of dialysis session was most strongly correlated with LVMI (Pearson correlation coefficient r = 0.59, P < .0001). LVH was best predicted by post-dialysis systolic BP (area under the curve, 0.83; 95% confidence interval, 0.72-0.94) and initial dialysis systolic BP (area under the curve, 0.81; 95% confidence interval, 0.70-0.92). Forty-four-hour ambulatory BP and BP variability did not significantly predict LVH. Initial dialysis mean arterial pressure and systolic BP and post-dialysis systolic BP are the strongest predictors of LVH, and may represent the potentially best treatment targets in hemodialysis patients to prevent end-organ damage. Further studies are needed to confirm whether treatment targeting these BP measurements can optimize cardiovascular outcomes.

Relationships Between Left Ventricular Structure and Function According to Cardiac MRI and Cardiac Biomarkers in End-Stage Renal Disease

BACKGROUND We sought to assess the relationships between left ventricular (LV) remodelling and the mechanical and uremic stressors in hemodialysis patients. METHODS In this prospective 2-centre cohort study, 67 prevalent hemodialysis patients were followed for 1 year. Data on routine bloodwork and predialysis blood pressure (BP) measurements were collected over a 12-week period. LV end-diastolic volume (LVEDV) and LV mass (LVM) were measured using cardiac magnetic resonance imaging and indexed. High-sensitivity troponin-I (hsTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), fibroblast growth factor 23 (FGF-23), and high-sensitivity C-reactive protein (hsCRP) were also measured. All study procedures were performed at baseline and at 1 year. We examined the relationships between LV remodelling and (1) NT-proBNP and hsTnI (LV stretch and injury); (2) ultrafiltration volume (UFV) and interdialytic weight gain (IDWT; volume overload); (3) predialysis BP measurements (pressure overload); and (4) biomarkers of inflammation (hsCRP) and fibrosis (FGF-23). RESULTS LVEDV was significantly associated with UFV and with IDWT, at baseline as well as at 1 year. NT-proBNP was significantly and negatively correlated with UFV and IDWT, respectively, at 1 year. There were significant correlations between systolic BP and LVM index, at baseline and at 1 year as well as longitudinally. Systolic BP was the only parameter longitudinally correlated with LVM/LVEDV. hsTnI was not associated with urea, parathyroid hormone, calcium, phosphorus, FGF-23, hsCRP, or hemoglobin. CONCLUSIONS We did not observe significant relationships between myocardial injury and markers of fibrosis, inflammation, and LV remodelling. Elevated predialysis systolic BP, which might represent a common mediator of pressure and volume overload, appears to be a dominant stimulus for LV remodelling.

Cardiac magnetic resonance imaging for non-invasive diagnosis of lipomatous hypertrophy of inter-atrial septum.

A 71-year-old asymptomatic woman is found to have an incidental cardiac mass on transthoracic echocardiography. Cardiac magnetic resonance (CMR) findings are consistent with lipotamous hypertrophy of the inter-atrial septum. Given the characteristic appearances on CMR, biopsy or surgery was not indicated and the patient was managed conservatively.

Association between conversion to in-center nocturnal hemodialysis and right ventricular remodeling

Background In-center nocturnal hemodialysis (INHD) is associated with favorable left ventricular (LV) remodeling. Although right ventricular (RV) structure and function carry prognostic significance, the impact of dialysis intensification on RV is unknown. Our objectives were to evaluate changes in RV mass index (MI), end-diastolic volume index (EDVI), end-systolic volume index (ESVI) and ejection fraction (EF) after conversion to INHD and their relationship with LV remodeling. Methods Of 67 conventional hemodialysis (CHD, 4 h/session, three times/week) patients, 30 continued on CHD and 37 converted to INHD (7-8 h/session, three times/week). Cardiac magnetic resonance imaging was performed at baseline and 1 year using a standardized protocol; an experienced and blinded reader performed RV measurements. Results At 1 year there were significant reductions in RVMI {-2.1 g/m2 [95% confidence interval (CI) -3.8 to - 0.4], P = 0.017}, RVEDVI [-9.5 mL/m2 (95% CI - 16.3 to - 2.6), P = 0.008] and RVESVI [-6.2 mL/m2 (95% CI - 10.9 to - 1.6), P = 0.011] in the INHD group; no significant changes were observed in the CHD group. Between-group comparisons showed significantly greater reduction of RVESVI [-7.9 mL/m2 (95% CI - 14.9 to - 0.9), P = 0.03] in the INHD group, a nonsignificant trend toward greater reduction in RVEDVI and no significant difference in RVMI and RVEF changes. There was significant correlation between LV and RV in terms of changes in mass index (MI) (r = 0.46), EDVI (r = 0.73), ESVI (r = 0.7) and EF (r = 0.38) over 1 year (all P < 0.01). Conclusions Conversion to INHD was associated with a significant reduction of RVESVI. Temporal changes in RV mass, volume and function paralleled those of LV. Our findings support the need for larger, longer-term studies to confirm favorable RV remodeling and determine its impact on clinical outcomes.

Left Ventricular Strain Analysis Using Cardiac MRI in Patients Undergoing In-centre Nocturnal Hemodialysis: Left Ventricular Strain in Hemodialysis

Intensified haemodialysis is associated with regression of left ventricular (LV) mass. Compared to LV ejection fraction, LV strain allows more direct assessment of LV function. We sought to assess the impact of in‐centre nocturnal haemodialysis (INHD) on global LV strain (radial, circumferential, and longitudinal) and torsion by cardiac MRI (CMR).

Cardiac MRI and radionuclide ventriculography for measurement of left ventricular ejection fraction in ICD candidates

OBJECTIVE Current guidelines provide left ventricular ejection fraction (LVEF) criterion for use of implantable cardioverter defibrillators (ICD) but do not specify which modality to use for measurement. We compared LVEF measurements by radionuclide ventriculography (RNV) vs cardiac MRI (CMR) in ICD candidates to assess impact on clinical decision making. METHODS This single-centre study included 124 consecutive patients referred for assessment of ICD implantation who underwent RNV and CMR within 30 days for LVEF measurement. RNV and CMR were interpreted independently by experienced readers. RESULTS Among 124 patients (age 64 ± 11 years, 77% male), median interval between CMR and RNV was 1 day; mean LVEF was 32 ± 12% by CMR and 33 ± 11% by RNV (p = 0.60). LVEF by CMR and RNV showed good correlation, but Bland-Altman analysis showed relatively wide limits of agreement (-12.1 to 11.4). CMR LVEF reclassified 26 (21%) patients compared to RNV LVEF (kappa = 0.58). LVEF by both modalities showed good interobserver reproducibility (ICC 0.96 and 0.94, respectively) (limits of agreement -7.27 to 5.75 and -8.63 to 6.34, respectively). CONCLUSION Although LVEF measurements by CMR and RNV show moderate agreement, there is frequent reclassification of patients for ICD placement based on LVEF between these modalities. Future studies should determine if a particular imaging modality for LVEF measurement may enhance ICD decision making and treatment benefit.

Left ventricular structure and diastolic function by cardiac magnetic resonance imaging in hypertrophic cardiomyopathy

Objective Diastolic dysfunction is common in hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD), but its relationships with left ventricular (LV) parameters have not been well studied. Our objective was to assess the relationship of various measures of diastolic function, and maximum left ventricular wall thickness (MLVWT) and left ventricular mass index (LVMI) in HCM, HHD and normal controls using cardiac magnetic resonance imaging (CMR). We also assessed LV parameters and diastolic function in relation to late gadolinium enhancement (LGE) and right ventricular (RV) hypertrophy in HCM. Methods 41 patients with HCM, 21 patients with HHD and 20 controls were studied. Peak filling rate (PFR), time to peak filling (TPF), MLVWT and LVMI were measured using CMR. LGE and RV morphology were assessed in HCM patients. Results MLVWT correlated with TPF in HCM (r = 0.38; p = 0.02), HHD (r = 0.58; p = 0.01) and controls (r = 0.54; p = 0.01); correlation between MLVWT and TPF was weaker in HCM than HHD. LVMI did not correlate with diastolic function. In HCM, LGE extent correlated with MLVWT (τ = 0.41; p = 0.002) and with TPF (τ = 0.29; p = 0.02). The HCM patients with RV hypertrophy had higher MLVWT (p < 0.001) and TPF (p = 0.03) than patients without RV hypertrophy. Conclusion MLVWT correlates with diastolic function (TPF) in HCM, HHD and controls. LVMI did not show significant correlation with TPF. The diastolic dysfunction in HCM is not entirely explained by wall thickening. LGE and RV involvement are associated with worse LV diastolic function, suggesting that these may be markers of more severe underlying myocardial disarray and fibrosis that contribute to diastolic dysfunction.

A case of anticoagulation-related suburothelial hemorrhage.

We report a case of a 38-year-old man with bilateral suburothelial hemorrhage secondary to anticoagulation therapy. The condition is best diagnosed with the combination of nonenhanced and excretory phase computer tomography. It represents a rare, but easily overlooked, complication of coagulopathy.