Arterial wave reflections and mortality in haemodialysis patients—only relevant in elderly, cardiovascularly compromised?

Abstract

Background. Chronic kidney disease (CKD) patients have a 3-30-fold increased risk of death compared with the general population. This mortality difference is even more pronounced in younger subjects. Two markers of aortic stiffness--aortic pulse wave velocity (PWV) and augmentation index (AIx)--have been prospectively related to all-cause and cardiovascular (CV) mortality in end-stage renal disease (ESRD) populations. The aims of our study were first, to confirm the important deleterious effect of arterial stiffness in uraemia and second, to assess the impact on survival of increased AIx in a relatively young non-diabetic dialysis population, with minimal CV disease. Methods. Ninety-two patients (mean age 42.6 AE 11.2 years) were included in the study and followed for a period of 61 AE 25 months. None of the patients had diabetes mellitus, and only 3.3% had prior history of CV disease. AIx was determined by applantation tonometry using a SphygmoCor Õ device (AtCor TM , PWV Inc., Westmead, Sydney, Australia). Results. Mean AIx in our study population was 19.9 AE 13.7%; other significant haemodynamic parameters were: systolic blood pressure (SBP) 129 AE 24 mmHg, pulse pressure 35.3 AE 17.5 mmHg with 27.2% of the study population receiving angiotensinconverting enzyme inhibitors (ACE-I). On univariate analysis, in our group AIx correlated with: body weight (P < 0.001), radial SBP (P < 0.001) and haemoglobin levels (P < 0.05). There was no correlation between AIx and any of the echocardiographic parameters. In the stepwise multiple regression analysis, the only independent predictors for AIx were weight (P < 0.001), SBP (P < 0.001) and haemoglobin (P < 0.05) with the model explaining 33% of the AIx variability (adjusted R 2 ¼ 0.33). During the follow-up period, 15 deaths were recorded. In the Cox analysis (P ¼ 0.014; chi square 20.7 for the model) the only independent predictors for all-cause mortality were age (P ¼ 0.001), left ventricular mass index (P ¼ 0.032) and ACE-I therapy (P ¼ 0.039) while AIx did not reach statistical significance. There was no difference in patients' survival when divided by AIx tertiles, assessed by the log rank test (P ¼ 0.78). Conclusion. Our results fail to support the notion that an increased effect of wave reflections on central arteries is a strong and independent predictor of mortality in all ESRD patients on haemodialysis. The effect of arterial wave reflections might be in fact dependent on patient age and concurrent comorbidity status.

Ambulatory Pulse Wave Velocity Is a Stronger Predictor of Cardiovascular Events and All-Cause Mortality Than Office and Ambulatory Blood Pressure in Hemodialysis Patients

“…7 In contrast, a study including 92 patients failed to prove that wave reflections is an independent predictor, as during 61 months of follow-up, no significant differences were noted in cumulative survival among quartiles of AIx (log-rank P=0.780). 30 The findings of this study clarify these issues, as we found that 48-hour ambulatory AIx(75) was significantly associated with higher risk of all-cause mortality or cardiovascular outcomes. Arterial stiffness and wave reflections are generally closely correlated with each other in the general population.…”

Renal Denervation in Moderate to Severe CKD

“…36 Amelioration in the arterial wave reflection is particularly significant because it has been found to predict all-cause mortality and cardiovascular disease in ESRD. 37,38 Our findings indicate that therapeutic renal denervation may rapidly affect the peripheral vasculature via a significant reduction of arterial stiffness in this patient cohort.…”

Central Hemodynamics and Target Organ Damage in Hypertension

“…Briet et al showed that the central pulse pressure was an independent predictor of the progression to end-stage renal disease in CKD patients (Briet et al 2011). Furthermore, some prospective studies have investigated the predictive ability of central pressure indices for cardiovascular prognosis in patients with endstage renal disease (London et al 2001;Safar et al 2002;Covic et al 2006) or in renal transplant recipients (Verbeke et al 2011). Most of the studies have validated that the central pulse pressure and augmentation index predict future cardiovascular events more accurately than, or independently of, the brachial pressure (Hashimoto and Ito 2012).…”