Nik Abidin

Relationship of dysglycemia to acute myocardial infarct size and cardiovascular outcome as determined by cardiovascular magnetic resonance

BackgroundImproved outcomes for normoglycemic patients suffering acute myocardial infarction (AMI) over the last decade have not been matched by similar improvements in mortality for diabetic patients despite similar levels of baseline risk and appropriate medical therapy. Two of the major determinants of poor outcome following AMI are infarct size and left ventricular (LV) dysfunction.MethodsNinety-three patients with first AMI were studied. 22 patients had diabetes mellitus (DM) based on prior history or admission blood glucose ≥11.1 mmol/l. 13 patients had dysglycemia (admission blood glucose ≥7.8 mmol/l but <11.1 mmol/l) and 58 patients had normoglycemia (admission blood glucose <7.8 mmol/l). Patients underwent cardiac magnetic resonance (CMR) imaging at index presentation and median follow-up of 11 months. Cine imaging assessed LV function and late gadolinium contrast-enhanced imaging was used to quantify infarct size. Clinical outcome data were collected at 18 months median follow-up.ResultsPatients with dysglycemia and DM had larger infarct sizes by CMR than normoglycemic patients; at baseline percentage LV scar (mean (SD)) was 23.0% (10.9), 25.6% (12.9) and 15.8% (10.3) respectively (p = 0.001), and at 11 months percentage LV scar was 17.6% (8.9), 19.1% (9.6) and 12.4% (7.8) (p = 0.017). Patients with dysglycemia and DM also had lower event-free survival at 18 months (p = 0.005).ConclusionsPatients with dysglycemia or diabetes mellitus sustain larger infarct sizes than normoglycemic patients, as determined by CMR. This may, in part, account for their adverse prognosis following AMI.

Cardiac imaging in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) carry a high cardiovascular risk. In this patient group, cardiac structure and function are frequently abnormal and 74% of patients with CKD stage 5 have left ventricular hypertrophy (LVH) at the initiation of renal replacement therapy. Cardiac changes, such as LVH and impaired left ventricular systolic function, have been associated with an unfavourable prognosis. Despite the prevalence of underlying cardiac abnormalities, symptoms may not manifest in many patients. Fortunately, a range of available and emerging cardiac imaging tools may assist with diagnosing and stratifying the risk and severity of heart disease in patients with CKD. Moreover, many of these techniques provide a better understanding of the pathophysiology of cardiac abnormalities in patients with renal disease. Knowledge of the currently available cardiac imaging modalities might help nephrologists to choose the most appropriate investigative tool based on individual patient circumstances. This Review describes established and emerging cardiac imaging modalities in this context, and compares their use in CKD patients with their use in the general population.

Echocardiography in Hemodialysis Patients: Uses and Challenges

Patients with end-stage renal disease undergoing hemodialysis have high rates of morbidity and mortality. Cardiovascular disease accounts for almost half of this mortality, with the single most common cause being sudden cardiac death. Early detection of abnormalities in cardiac structure and function may be important to allow timely and appropriate cardiac interventions. Echocardiography is noninvasive cardiac imaging that is widely available and provides invaluable information on cardiac morphology and function. However, it has limitations. Echocardiography is operator dependent, and image quality can vary depending on the operators experience and the patients acoustic window. Hemodialysis patients undergo regular hemodynamic changes that also may affect echocardiographic findings. An understanding of the prognostic significance and interpretation of echocardiographic results in this setting is important for patient care. There are some emerging techniques in echocardiographic imaging that can provide more detailed and accurate information compared with conventional 2-dimensional echocardiography. Use of these novel tools may further our understanding of the pathophysiology of cardiac disease in patients with end-stage renal disease undergoing hemodialysis.

Measurement of left ventricular dimensions with contrast-enhanced three-dimensional cine imaging facilitated by k-t SENSE

AimTo compare three-dimensional (3D) k-t sensitivity encoded (k-t SENSE) cine cardiovascular magnetic resonance (CMR), before and after contrast administration, against standard 2D imaging for the assessment of left ventricular volumes and mass.MethodTwenty-six subjects (14 volunteers, 12 patients) underwent multiple breathhold 2D balanced turbo-field echo cine CMR in addition to k-t SENSE accelerated 3D imaging (acceleration factor 5; 5× k-t SENSE), performed before and after administration of a high-relaxivity gadolinium-based contrast agent (Gadobutrolum). k-t acceleration factors of 7 and 10 were also assessed in six volunteers. Left ventricular end diastolic volume (EDV), end systolic volume (ESV), mass, and ejection fraction (EF) were calculated for each method.ResultsThere was at least moderate agreement between the EDV, ESV, mass and EF calculated by 2D and 3D 5× k-t SENSE methods before contrast (concordance coefficients 0.92, 0.95, 0.97, 0.92, respectively). Agreement improved following contrast (concordance coefficients 0.97, 0.99, 0.98, 0.93, respectively). The 3D method underestimated all parameters compared to 2D (mean bias pre-contrast 6.1 ml, 0.6 ml, 3.5 g, 2.0% respectively). 3D image quality scores were significantly poorer than 2D, showing a non-significant trend to improvement following contrast administration. Parameters derived with k-t acceleration factors of 7 and 10 showed poorer agreement with 2D values.ConclusionLeft ventricular volumes and mass are reliably assessed using 3D 5× k-t SENSE accelerated CMR. Contrast administration further improves agreement between 5× k-t SENSE and 2D-derived measurements. k-t acceleration factors greater than 5, though feasible, produce poorer agreement with 2D values.

Novel Approach to Cardiovascular Outcome Prediction in Haemodialysis Patients

Background: Cardiovascular mortality is high in haemodialysis (HD) patients. Arterial stiffness and global longitudinal strain (GLS) are important non-atheromatous cardiovascular risk predictors. No study has encompassed both parameters in a combined model for prediction of outcomes in HD patients. This is important because left ventricular (LV) dysfunction can result from fibrotic remodelling secondary to increased arterial stiffness. Methods: Two hundred and nineteen HD patients had pulse wave velocity (PWV) and echocardiography (including GLS) assessments. Patients were followed-up until death, transplantation or November 16, 2015, whichever happened first. Pearsons correlation coefficient was used to determine factors associated with PWV and GLS. A multivariable Cox regression model investigated factors associated with all-cause, cardiac death and events. Results: One hundred and ninety eight HD patients had full datasets (median age 64.2, 68.7% males) with a mean LV ejection fraction (LVEF) of 61.7 ± 10.1% and GLS -13.5 ± 3.3%; 51% had LV hypertrophy. Forty eight deaths (15 cardiac) and 44 major cardiac events occurred during a median follow-up of 27.6 (25th-75th percentile, 17.3-32.7) months. In separate survival models, PWV and GLS were independently associated with all-cause mortality; however, in a combined model, LV mass indexed to height2.7 (LVMI/HT2.7; adjusted hazard ratio (HR) 1.02, 95% CI 1.00-1.04) and PWV (adjusted HR 1.23, 95% CI 1.03-1.47) were significant. PWV was neither associated with cardiac death nor associated with related cardiac events. However, GLS was associated with cardiac death (adjusted HR 1.24, 95% CI 1.00-1.54) and cardiac events (adjusted HR 1.13, 95% CI 1.03-1.25). Conclusions: PWV and LVMI/HT2.7 were superior to GLS in prediction of all-cause mortality. However, GLS was associated with cardiac death and events even when accounting for LVEF and LVMI/HT2.7.

Native T1 mapping versus CMR Feature Tracking (FT) derived strain analysis for the assessment of cardiac disease manifestation in Anderson Fabry

Background Cardiovascular sequelae represent a leading cause of mortality in Fabry disease. Early detection of cardiac involvement is therefore a subject of considerable interest. Low native T1 values have been shown to be associated with echocardiographic markers of early systolic and diastolic dysfunction, even in those without left ventricular hypertrophy (LVH), and conceptually could be used to optimise the efficacy of Enzyme replacement therapy (ERT). The purpose of this study was to determine the relationship of both, native T1 and feature tracking CMR (FT-CMR) derived strain parameters, with maximal LV wall thickness and LVmass in Fabry’s as a clinical marker of cardiac disease manifestation.

Non-recruitment to and selection bias in studies using echocardiography in hemodialysis patients

It is unknown whether patients recruited to renal cardiac imaging studies are fully representative of the investigated population and whether there are differences in characteristics and survival between participants and non‐participants (excluded or declined consent).

020 Comprehensive cardiovascular magnetic resonance assessment of anderson-fabry cardiomyopathy- natural history and assessment of treatment effect

Background The Anderson Fabry Cardiomyopathy (AFC) is heterogeneous, complex, and its pathophysiology remains incompletely understood. There is uncertainty regarding the optimal timing and impact of enzyme replacement therapy (ERT) in cardiac involvement, with a pressing need for biomarkers able to identify early disease, monitor and guide treatment. Objectives The aims of this study were two-fold: 1) to perform comprehensive cardiac phenotyping in a large cohort of Anderson-Fabry disease (AFD), and 2) characterise their short-term natural history and assess the impact of ERT using multi-parametric Cardiac Magnetic resonance imaging (MPCMRi), echocardiography and ECG analysis. Methods 113 prospectively enrolled, genetically-confirmed, AFD patients were compared to 20 age-matched healthy volunteers (HVs). 37 of these patients re-attended for a one-year follow-up scan, and were sub-grouped according to treatment status (newly started on ERT, ERT naïve, and established on ERT). Results The AFC is characterised by increased LV mass of several different hypertrophic patterns, impaired LV global longitudinal strain and left atrial function, low myocardial native T1, high T2, and increased extracellular volume fraction. Significantly higher T1s were seen in the inferolateral wall, even before the development of increased wall thickness or LV mass, or LGE. A newly proposed marker of disease severity, the ‘T1 ratio’, reflects the relationship between inferolateral and remote myocardial T1, and strongly correlated with LV mass, percentage LGE and ECV fraction, whilst avoiding potential uncertainty caused by pseudo-normalisation of T1s in severe AFD. ERT initiation reduced LVM. T1 values (excluding the inferolateral wall) fell significantly in untreated patients (974±36 ms v 955±44 ms, p=0.04) associated with a significant increase in voxel based spread (288 v 350, p=0.02), whereas both treatment groups showed no change in T1 values. The T1 ratio showed a trend towards improvement (0.94±0.08 v 0.98±0.1, p=0.05) in the established ERT group. Electrocardiography and echocardiography did not detect disease progression or treatment effects in any group. Conclusions AFC is a complex pathology with intracellular and extracelluar disease components. MPCMRi elucidates these disease processes and allows early disease detection, and possibly disease and treatment monitoring.

128 Abnormal Global Longitudinal Strain is Associated with All-Cause Mortality in Haemodialysis Patients

Introduction Cardiovascular mortality is high in end-stage renal disease patients undergoing haemodialysis (HD). Early detection of cardiac dysfunction is important. Left ventricular global longitudinal strain (GLS) measures the maximal shortening of myocardial longitudinal length during systole compared to the resting length in diastole. Reduced GLS may reflect abnormal systolic function before loss of ejection fraction (EF) becomes apparent. We aimed to determine the prevalence, clinical correlates and prognostic value of abnormal GLS in stable HD patients. Methods Clinical and echocardiographic data were obtained in a prospective study of HD patients at one centre. Survival analysis for GLS was performed using Cox regression adjusted for age, co-morbidities, dialysis chronicity, laboratory data, left ventricular mass index adjusted for height (LVMIHt2.7) and Teicholz EF. Results 199 patients had adequate speckle tracking images; the mean age was 62 ± 14years, 69% were male, 39% had diabetes, 29% heart failure, 17% coronary artery disease. The mean GLS was -13.4 ± 3.5%, LV ejection fraction (LVEF) 63.8 ± 12.9% and LVMIHt2.7 53.6 ± 17.2g/m2.7. 98% of patients had abnormal GLS (>-20%), compared with 14% with reduced LVEF(<50%) and 55% with LV hypertrophy. Factors associated with an abnormal GLS included LVMIHt2.7 (OR 1.06, 95% CI 1.04–1.09, P < 0.01), LVEF (OR 0.96, 95% CI 0.94–0.99, P < 0.01) and diabetes (OR 2.04, 95% CI 1.08–3.9, p = 0.03). Median follow-up was 24 (17–30) months, during which there were 41 deaths (21%). After adjustment for age, diabetes, coronary artery disease, LVEF, LVMIHt 2.7, 3 month-averaged serum potassium and albumin, a less negative GLS remained an independent predictor of all-cause mortality (HR 1.18 for each 1% worsening change in GLS, 95% CI 1.03–1.35, P = 0.02). Figure 1.Abstract 128 Figure 1 Survival in<= median versus> median GLS (median = -13.7%) Conclusions Abnormal GLS is highly prevalent amongst HD patients, and appears to be a better marker of all-cause mortality in stable HD patients than the standard echocardiographic parameters LVEF and LVMIHt2.7.

Three-Dimensional Imaging of a Central Venous Dialysis Catheter Related Infected Thrombus.

Three-dimensional (3D) echocardiography is becoming widely available and with novel applications. We report an interesting case of a 68-year-old lady with a central venous thrombosis coincident with both a dialysis catheter infection and a recent pacemaker insertion. Two-dimensional transesophageal echocardiography was unable to delineate whether the thrombosis was involved with the pacemaker wire or due to the tunneled catheter infection. The use of 3D echocardiography was able to produce distinct images aiding diagnosis. This circumvented the need for invasive investigations and inappropriate, high-risk removal of the pacing wire. This case highlights the emerging application of 3D echocardiography in routine nephrology practice.