Nicola C. Edwards

Effect of Spironolactone on Left Ventricular Mass and Aortic Stiffness in Early-Stage Chronic Kidney Disease: A Randomized Controlled Trial

OBJECTIVES We sought to determine whether the addition of spironolactone to angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) improves left ventricular mass and arterial stiffness in early-stage chronic kidney disease (CKD). BACKGROUND Chronic kidney disease is associated with a high risk of cardiovascular disease and a high prevalence of left ventricular hypertrophy and arterial stiffness that confer an adverse prognosis. It is believed that these abnormalities are in part a result of activation of the renin-angiotensin-aldosterone system. METHODS After an active run-in phase with spironolactone 25 mg once daily, 112 patients with stage 2 and 3 CKD with good blood pressure control (mean daytime ambulatory blood pressure <130/85 mm Hg) on established treatment with ACE inhibitors or ARBs were randomized to continue spironolactone or to receive a matching placebo. Left ventricular mass (cardiac magnetic resonance) and arterial stiffness (pulse wave velocity/analysis, aortic distensibility) were measured before run in and after 40 weeks of treatment. RESULTS Compared with placebo, the use of spironolactone resulted in significant improvements in left ventricular mass (-14 +/- 13 g vs. +3 +/- 11 g, p < 0.01), pulse wave velocity (-0.8 +/- 1.0 m/s vs. -0.1 +/- 0.9 m/s, p < 0.01), augmentation index (-5.2 +/- 6.1% vs. -1.4 +/- 5.9%, p < 0.05), and aortic distensibility (0.69 +/- 0.86 x 10(-3) mm Hg vs. 0.04 +/- 1.04 x 10(-3) mm Hg, p < 0.01). CONCLUSIONS The use of spironolactone reduces left ventricular mass and improves arterial stiffness in early-stage CKD. These effects suggest that aldosterone exerts adverse cardiovascular effects in CKD and that spironolactone is worthy of further study as a treatment that could reduce adverse cardiovascular events. (Is Spironolactone Safe and Effective in the Treatment of Cardiovascular Disease in Mild Chronic Renal Failure; NCT00291720).

Arterial disease in chronic kidney disease

End stage renal disease is associated with a very high risk of premature cardiovascular death and morbidity. Early stage chronic kidney disease (CKD) is also associated with an increased frequency of cardiovascular events and is a common but poorly recognised and undertreated risk factor. Cardiovascular disease in CKD can be attributed to two distinct but overlapping pathological processes, namely atherosclerosis and arteriosclerosis. While the risk of athero-thrombotic events such as myocardial infarction is elevated, arteriosclerosis is the predominant pathophysiological process involving fibrosis and thickening of the medial arterial layer. This results in increased arterial stiffness causing left ventricular hypertrophy and fibrosis and the exposure of vulnerable vascular beds such as the brain and kidney to high pressure fluctuations causing small vessel disease. These pathophysiological features are manifest by a high risk of lethal arrhythmia, congestive heart failure, myocardial infarction and stroke. Recent work has highlighted the importance of aldosterone and disordered bone mineral metabolism.

Aortic distensibility and arterial–ventricular coupling in early chronic kidney disease: a pattern resembling heart failure with preserved ejection fraction

Objectives: To examine arterial and left ventricular function and their interaction in patients with early-stage chronic kidney disease (CKD). Design and setting: Cross-sectional observational study in a university teaching hospital. Patients: 117 patients with stage 2 (60–89 ml/min/1.73 m2) or stage 3 (30–59 ml/min/1.73 m2) non-diabetic CKD, without overt cardiovascular disease were compared with 40 controls. Interventions: Aortic distensibility and left ventricular mass were assessed using cardiac magnetic resonance imaging. Systolic and diastolic ventricular function and arterial–ventricular elastance (stiffness) were assessed by transthoracic echocardiography. Main outcome measures: Arterial stiffness as measured by aortic distensibility and arterial elastance. Left ventricular mass, left ventricular systolic and diastolic function, including end-diastolic and end-systolic elastance and their relationship with arterial elastance. Results: Compared with controls, patients with CKD 2 and CKD 3 had reduced aortic distensibility (4.12 (1.3) vs 2.94 (1.8) vs 2.18 (1.8)×10–3 mm Hg, p<0.01), increased arterial elastance (1.4 (1.3) vs 1.65 (0.40) vs 1.74 0.48) mm Hg, p<0.05) and increased end-systolic (1.88 (0.48) vs 2.43 (0.83) vs 2.42(0.78) mm Hg/ml, p<0.05) and end diastolic elastances (0.07 (0.04) vs 0.11 (0.04) vs 0.12 (0.04, p<0.01). Aortic distensibility was positively correlated with estimated glomerular filtration rate (r = 0.349, p<0.01) and indices of elastance were inversely correlated (r =  0.284, p<0.05). Systolic function was not impaired in patients with early CKD compared with controls but diastolic filling velocities (Em) were reduced (8.1 (0.9) vs 7.9 (0.6) vs 7.5 (0.7) cm/s, p<0.01) while mean left atrial pressure (E/Em) was increased (5.6 (1.1), vs 7.4 (1.8) vs 8.0 (2.4), p<0.01) and end-diastolic elastance was increased. Conclusions: Early-stage CKD is characterised by reduced aortic distensibility and increases in arterial, ventricular systolic and diastolic stiffness; arterial–ventricular coupling is preserved. This pattern of pathophysiological abnormalities resembles that seen in heart failure with preserved ejection fraction and may account for the high levels of cardiovascular morbidity and mortality in patients at all stages of CKD. Trial Registration Number: NCT00291720

Glucose-insulin-potassium and tri-iodothyronine individually improve hemodynamic performance and are associated with reduced troponin I release after on-pump coronary artery bypass grafting.

Background— Both glucose-insulin-potassium (GIK) and tri-iodothyronine (T3) may improve cardiovascular performance after coronary artery surgery (CABG) but their effects have not been directly compared and the effects of combined treatment are unknown. Methods and Results— In 2 consecutive randomized double-blind placebo-controlled trials, in patients undergoing first time isolated on-pump CABG between January 2000 and September 2004, 440 patients were recruited and randomized to either placebo (5% dextrose) (n=160), GIK (40% dextrose, K+ 100 mmol · L−1, insulin 70 u · L−1) (0.75 mL · kg−1 h−1) (n=157), T3 (0.8 &mgr;g · kg−1 followed by 0.113 &mgr;g · kg−1 h−1) (n=63) or GIK+T3 (n=60). GIK/placebo therapy was administered from start of operation until 6 hours after removal of aortic cross-clamp (AXC) and T3/placebo was administered for a 6-hour period from removal of AXC. Serial hemodynamic measurements were taken up to 12 hours after removal of AXC and troponin I (cTnI) levels were assayed to 72 hours. Cardiac index (CI) was significantly increased in both the GIK and GIK/T3 group in the first 6 hours compared with placebo (P<0.001 for both) and T3 therapy (P=0.009 and 0.029, respectively). T3 therapy increased CI versus placebo between 6 and 12 hours after AXC removal (P=0.01) but combination therapy did not. Release of cTnI was lower in all treatment groups at 6 and 12 hours after removal of AXC. Conclusions— Treatment with GIK, T3, and GIK/T3 improves hemodynamic performance and results in reduced cTnI release in patients undergoing on-pump CABG surgery. Combination therapy does not provide added hemodynamic effect.

Myocardial strain measurement with feature-tracking cardiovascular magnetic resonance: normal values.

AIMS Myocardial deformation is a key to clinical decision-making. Feature-tracking cardiovascular magnetic resonance (FT-CMR) provides quantification of motion and strain using standard steady-state in free-precession (SSFP) imaging, which is part of a routine CMR left ventricular (LV) study protocol. An accepted definition of a normal range is essential if this technique is to enter the clinical arena. METHODS AND RESULTS One hundred healthy individuals, with 10 men and women in each of 5 age deciles from 20 to 70 years, without a history of cardiovascular disease, diabetes, renal impairment, or family history of cardiovascular disease, and with a normal stress echocardiogram, underwent FT-CMR assessment of LV myocardial strain and strain rate using SSFP cines.Peak systolic longitudinal strain (Ell) was -21.3 ± 4.8%, peak systolic circumferential strain (Ecc) was -26.1 ± 3.8%, and peak systolic radial strain (Err) was 39.8 ± 8.3%. On Bland-Altman analyses, peak systolic Ecc had the best inter-observer agreement (bias 0.63 ± 1.29% and 95% CI -1.90 to 3.16) and peak systolic Err the least inter-observer agreement (bias 0.13 ± 6.41 and 95% CI -12.44 to 12.71). There was an increase in the magnitude of peak systolic Ecc with advancing age, which was greatest in subjects over the age of 50 years (R(2) = 0.11, P = 0.003). There were significant gender differences (P < 0.001) in peak systolic Ell, with a greater magnitude of deformation in females (-22.7%) than in males (-19.3%). CONCLUSION Normal values for myocardial strain measurements using FT-CMR are provided. All circumferential and longitudinal based variables had excellent intra- and inter-observer variability.

Cardiovascular Effects of Sevelamer in Stage 3 CKD

Serum phosphate independently predicts cardiovascular mortality in the general population and CKD, even when levels are in the normal range. Associations between serum phosphate, arterial stiffness, and left ventricular (LV) mass suggest a possible pathophysiological mechanism, potentially mediated by the phosphaturic hormone fibroblast growth factor-23 (FGF-23). To what extent the phosphate binder sevelamer modulates these effects is not well understood. In this single-center, randomized, double-blind, placebo-controlled trial, we enrolled 120 patients with stage 3 nondiabetic CKD. After a 4-week open-label run-in period, during which time all patients received sevelamer carbonate, we randomly assigned 109 patients to sevelamer (n=55) or placebo (n=54) for an additional 36 weeks. We assessed LV mass and systolic and diastolic function with cardiovascular magnetic resonance imaging and echocardiography, and we assessed arterial stiffness by carotid-femoral pulse wave velocity. The mean age was 55 years, and the mean eGFR was 50 ml/min per 1.73 m(2). After 40 weeks, we found no statistically significant differences between sevelamer and placebo with regard to LV mass, systolic and diastolic function, or pulse wave velocity. Only 56% of subjects took ≥ 80% of prescribed therapy; in this compliant subgroup, treatment with sevelamer associated with lower urinary phosphate excretion and serum FGF-23 but not serum phosphate, klotho, vitamin D, or cardiovascular-related outcomes of interest. In conclusion, this study does not provide evidence that sevelamer carbonate improves LV mass, LV function, or arterial stiffness in stage 3 nondiabetic CKD.

Subclinical Abnormalities of Left Ventricular Myocardial Deformation in Early-Stage Chronic Kidney Disease : The Precursor of Uremic Cardiomyopathy?

BACKGROUND Abnormal left ventricular (LV) deformation is an independent predictor of poor cardiovascular outcome in end-stage renal disease. Studies in early-stage chronic kidney disease (CKD) have not been performed despite the known graded inverse relationship between glomerular filtration rate and adverse cardiovascular events. METHODS Forty patients with CKD stage 2 or 3 and no history of cardiovascular disease or diabetes and 30 healthy controls underwent Doppler myocardial imaging for longitudinal deformation (strain/strain rate). RESULTS There were no differences in LV ejection fraction or systolic tissue Doppler velocities between patients with CKD and controls. In CKD, mean global strain (-15% +/- 4% vs -17% +/- 3%, P <.01) and mean global strain rate were reduced compared with controls (-0.88 +/- 0.16 vs -1.06 +/- 0.31, P <.05). Peak systolic strain was reduced in the basal lateral (-13.9% +/- 0.9% vs -17.9% +/- 1.02%, P <.01), basal septal (-17.1% +/- 0.8% vs -19.4% +/- 0.77%, P <.05), and mid-septal (-16.4% +/- 0.78% vs -18.9% +/- 0.88%, P <.05) walls with more basal postsystolic shortening (P <.01). Peak systolic strain rate was reduced in the basal lateral, mid-lateral, and mid-septal segments (P <.05). CONCLUSION Conventional measures of systolic function are preserved in early-stage CKD, but systolic deformation is abnormal, consistent with an adverse cardiovascular prognosis.

Serum phosphate is associated with left ventricular mass in patients with chronic kidney disease: a cardiac magnetic resonance study.

Objective To explore the relationship between serum phosphate, arterial stiffness and left ventricular mass (LVM) in patients with early-stage chronic kidney disease (CKD). Design A cross-sectional observational study. Setting Single centre. Patients 208 patients with stage 2 to stage 4 non-diabetic CKD. Interventions Arterial stiffness was determined through measurement of aortic pulse wave velocity (PWV). Cardiac magnetic resonance was used to determine LVM. Main outcome measure Relationship between serum phosphate, aortic PWV and LVM. Results Mean age was 54±13 years, mean glomerular filtration rate was 50±15 ml/min/1.73 m2, mean serum phosphate was 1.11±0.21 mmol/l and mean PWV was 8.6±2.1 m/s. When the cohort was divided into quartiles according to serum phosphate, LVM increased across quartiles (p=0.04), with no significant differences in age, kidney function, blood pressure or PWV. Serum phosphate correlated with LVM (r=0.173; p=0.01), but PWV did not (p=0.2). In a regression model containing gender, serum phosphate, office systolic blood pressure, albumin/creatinine ratio and haemoglobin, 30% of the variation in LVM was explained (p<0.0005), with serum phosphate accounting for 5% of the variance. Conclusion Serum phosphate is independently associated with LVM in patients with CKD. Interventional studies are required to determine whether this association is causative and whether reducing phosphate exposure reduces LVM in this population.

Comparison of magnetic resonance feature tracking for systolic and diastolic strain and strain rate calculation with spatial modulation of magnetization imaging analysis

To compare cardiovascular magnetic resonance‐feature tracking (CMR‐FT) with spatial modulation of magnetization (SPAMM) tagged imaging for the calculation of short and long axis Lagrangian strain measures in systole and diastole.

Atrial Fibrillation in CKD: Balancing the Risks and Benefits of Anticoagulation

Chronic kidney disease (CKD) and atrial fibrillation are common conditions that often coexist and are associated with increased risk of stroke. Despite the wealth of evidence for optimal management of atrial fibrillation in the general population, the role of anticoagulation with warfarin in individuals with CKD with atrial fibrillation is far less well defined. Current recommendations for anticoagulation in patients treated with dialysis and those with an earlier stage of CKD are based on clinical trials in the general atrial fibrillation population that have largely excluded individuals with CKD. Observational studies of anticoagulation in dialysis patients have produced conflicting results, mainly because of increased risk of bleeding. This, together with warfarins potential adverse effects on ectopic/vascular calcification and progression of CKD, may result in negating the benefits associated with anticoagulation in the general population. With the recent emergence of novel oral anticoagulants, there is an urgent need for a better understanding of the complex inter-relationship among CKD, atrial fibrillation, stroke, and bleeding risk. This knowledge is paramount to optimize the potential benefits of treatment and minimize the potential harms in this very high-risk and growing population.