Wave reflections and cardiac hypertrophy in chronic uremia. Influence of body size.

Abstract

Arterial wave reflections (AWRs), an important determinant of cardiac afterload, are increased in hemodialysis patients. However, an association between AWRs and left ventricular hypertrophy has not been established in these subjects. We therefore sought an association between these two parameters in a cross-sectional study of two outpatient hemodialysis populations. AWRs were quantified (augmentation index, percent) as the ratio of the height of the late systolic peak to the total height of the carotid pulse wave recorded with a micromanometer-tipped probe. AWRs were determined in 44 hemodialysis patients, 22 with pronounced AWRs (group A: augmentation index >12%), and 22 with small or moderate AWRs (group B: augmentation index <12%). The groups were matched for age, sex, blood pressure, and hemodialysis duration. Left ventricular size was determined by echocardiography. Despite lower body size (P<.005) and similar blood pressure, cardiac output, peripheral resistance, and aortic pulse wave velocity, group A patients had greater left ventricular mass (P<.01). For the population as a whole, left ventricular mass and AWRs were positively correlated (P<.0001) independent of age, blood pressure, hemodialysis duration, or body size. Lesser body height was the principal factor associated with increased AWRs in group A (P<.001). We conclude that in hemodialysis patients AWRs are associated with the development of left ventricular hypertrophy and that small body height is a risk factor for long-term cardiovascular complications. 13 Both nonhemodynamic factors and hemodynamic alterations due to chronic flow and pressure overload play a role in LVH development in these patients. 13 Even though hypertension is held responsible for such a high prevalence, LVH develops and progresses with time on hemodialysis and is only loosely correlated with blood pressure (BP) level, at least as reflected by usual BP measurements. 13 However, systolic BP (SBP) and diastolic BP (DBP) are merely the limits of BP fluctuation during the cardiac cycle and not the best expression of the load against which the left ventricle must work. Indeed, SBP in the left ventricle or aorta is also determined by ventricular ejection and to a degree is dependent on preload. -5Aortic input impedance, determined by arteriolar tone, aortic distensibility and diameter, and the intensity and timing of arterial wave reflections (AWRs), provides valuable information concerning the characteristics of the arterial system in accepting pulsatile flow from the

Diastolic blood pressure is an important determinant of augmentation index and pulse wave velocity in young, healthy males

“…An inverse correlation between augmentation index and body height has been described earlier and has been interpreted as a result of earlier wave reflection in short people. 13,18,43 In the present study, this association was not significant for several reasons. We studied only males and the relation between augmentation index and height is attenuated in males compared to females.…”

Central blood pressure measurement may improve risk stratification

“…23 Others have shown central pressure waveform indices to be important predictors of LV and carotid artery structure. 24,25 We have also found an independent association between central pulse pressure and LV mass in patients with type 2 diabetes mellitus. 26 Importantly, Hashimoto et al 27 recently reported a strong correlation between the change in pulse pressure amplification and the change in LV mass in response to anti-hypertensive therapy.…”

Renal Denervation in Moderate to Severe CKD

“…34 Finally, the improvement in augmentation index observed in our patients with CKD may also be of clinical significance. Higher augmentation index is associated with target-organ damage in hemodialysis patients 35 and with microalbuminuria in those with essential hypertension. 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.…”