Early morning hemodynamic changes and left ventricular hypertrophy and mortality in hemodialysis patients

Objective: Amplified early morning increase in BP, a phenomenon accompanied by a parallel rise in heart rate (HR), is a marker of high cardiovascular risk in the general population. The early morning changes in these parameters have not been investigated in the hemodialysis population. Design and method: In a pilot, single center, study including a series of 58 hemodialysis patients we measured the pre-awakening BP and HR surges and the nocturnal dipping of the same parameters as well as other established indicators of autonomic function (weighted 24h systolic BP and HR variability) and tested their relationship with the left ventricular mass index (LVMI) and with the risk of death over a median follow up of 40 months. Results: The pre-awakening HR surge (r = -0.46, P = 0.001) was inversely associated with LVMI and the risk of death [HR (1 unit): 0.89, 95% CI: 0.83-0.96, P = 0.001] while the corresponding BP surge largely failed to associate with these outcomes. The link between the pre-awakening HR surge with LVMI and death was robust and largely independent of established risk factors in the hemodialysis population, including the nocturnal dipping of BP. Weighted 24h systolic BP and HR variability did not correlate with LVMI (all P>0.11) nor with the risk of death (P>0.11) and these parameters were also independent of the nocturnal dipping of systolic BP and HR. Conclusions: This pilot study suggests that the low early morning changes in HR, likely reflecting enhanced sympathetic activity, entail a high risk for LVH and mortality in the hemodialysis population.