Determinants of hypertension and left ventricular function in end stage renal failure: a pilot study using cardiovascular magnetic resonance imaging

Abstract

Cardiovascular disease is the principal cause of mortality in patients with renal failure. Left ventricular (LV) abnormalities are adverse prognostic indicators for cardiovascular outcome. The aim of this study was to use cardiac magnetic resonance scanning (CMR) to define LV functional abnormalities in haemodialysis (HD) patients and clarify the determinants of blood pressure (BP) and the effect of anaemia in this population. We studied 44 HD patients and 11 controls with CMR performed following dialysis. Forty patients and 11 controls completed the study. LV mass (P<0.001) and estimated systemic vascular resistance (SVR) (P = 0.002) were significantly higher in the dialysis group compared to controls. LV ejection fraction (P = 0.002) and SV (P = 0.043) were lower than controls. In the HD patients, BP correlated significantly with cardiac output (CO; r = 0.569, P<0.001) and end diastolic volume (EDV; r = 0.565, P<0.001) but there was no correlation between BP and SVR (r = 0.201, P = 0.594). Haemoglobin was inversely correlated with both CO (r = -0.531, P<0.001) and EDV (r = -0.493, P = 0.001) and positively with SVR (r = 0.402, P = 0.009). HD patients had a higher LV mass and lower ejection fraction than controls. The relationship of BP with CO, but not SVR, supports the theory that a major determinant of BP is intravascular volume and CO rather than vascular resistance although there was a fixed increase in SVR in this population. Improved understanding of the mechanisms underlying increased SVR and improved control of CO and intravascular volume may allow better therapeutic strategies. CMR provides insights into the pathophysiology of hypertension and LV dysfunction in HD patients.

Determinants of Left Ventricular Mass and Hypertrophy in Hemodialysis Patients Assessed by Cardiac Magnetic Resonance Imaging

“…This contrasts with other published data that demonstrated a strong correlation between LVM and anemia (11,28), and the most likely explanation is the higher values and narrower range in our cohort (mean hemoglobin 11.3 g/dl; SD 1.3) compared with other studies.…”

“…Since 2002 (10,11,13), we have used CMR as part of the standard assessment of patients for renal transplantation. The renal transplant unit at the Western Infirmary (Glasgow, Scotland, UK) provides transplant services to a population of 2.8 million people in the west of Scotland.…”

“…This technique has been established as the most accurate noninvasive method of assessing ventricular dimensions in patients, including those with stage 5 chronic kidney disease (10,11). In particular, measurements obtained by echocardiography tend to overestimate LVMI, particularly at higher values, when compared with CMR (12).…”

Pediatric Myocardial Stunning Underscores the Cardiac Toxicity of Conventional Hemodialysis Treatments

“…We found no significant association between these aforementioned risk factors and the severity of myocardial stunning, possibly because cardiorenal performance is influenced by a number of humoral and genetic factors (26) that act collectively to exert an effect but in isolation, particularly in pediatrics, are too small to be detectable from our sample size. The major determinant of intradialytic BP is cardiac output and end diastolic volume (27), but clearly regional LV function is important as evidenced by reports of reduced hemodynamic stability in patients developing myocardial stunning despite below average UF volumes (13). Shoji et al (28) found BP reduction during dialysis and not hypertension in adult HD patients as a factor that influenced survival negatively.…”

Renal Transplantation Is Not Associated with Regression of Left Ventricular Hypertrophy

“…CMR was performed using a 1.5-Tesla MRI scanner (Sonata, Siemens, Erlangan, Germany) with LV mass and function assessed as described previously (9). In hemodialysis patients, CMR was consistently performed 24 h after the end of the last dialysis session.…”