Probing dry-weight improves left ventricular mass index

Abstract

Background: Although probing dry-weight improves blood pressure control, its effect on echocardiographic left ventricular mass index (LVMI) is unknown.

Methods: Shortly following dialysis, 292 echocardiograms in 150 patients participating in the DRIP trial were obtained at baseline and longitudinally every 4 weeks on 2 occasions.

Results: At baseline, LVMI was 136.3 g/m(2) in the control group and 138.7 g/m(2) in the ultrafiltration group (p > 0.2 for difference). The change from baseline in LVMI in the control group was +3.5 g/m(2) at 4 weeks and +0.3 g/m(2) at 8 weeks (p > 0.2 for both changes). The change from baseline in LVMI in the ultrafiltration group was -7.4 g/m(2) at 4 weeks (p = 0.005) and -6.3 g/m(2) at 8 weeks (p = 0.045). With ultrafiltration, the change in LVMI diameter was -10.9 g/m(2) more compared to the control group at 4 weeks (p = 0.012) and -6.6 g/m(2) more compared to the control group at 8 weeks (p = 0.21). The reduction in interdialytic ambulatory blood pressure was also greater in response to probing dry-weight in those in the top half of LVMI at baseline (p = 0.02 for interaction effect at week 8).

Conclusion: LVMI, an important determinant of prognosis among long-term dialysis patients, is responsive to probing dry-weight.

Fig. 1

Changes in 44-hour interdialytic systolic blood pressure as a function of the echocardiographic volume parameter. The echocardiographic volume parameter was dichotomized at the median value at the baseline visit, yielding a low index and a high index. Compared to the high index, low index would be expected to have less volume. The forest plot shows the additional change in systolic blood pressure in the ultrafiltration group compared to the change in the control group. The mean additional change in blood pressure (shown in the forest plot) in the ultrafiltration group at 4 and 8 weeks did not differ between low index and high index. IVSd = Intraventricular septal thickness at diastole; LVId = left ventricular interior diameter at diastole; LVPWd = left ventricular posterior wall thickness at diastole; MWFS = midwall fractional shortening.

Fig. 2

Changes in 44-hour interdialytic systolic blood pressure as a function of change in the echocardiographic volume parameter. As in figure 1, the echocardiographic volume parameter was dichotomized at the median value at the baseline visit, yielding a low index and a high index. This value was then used to classify patients into low- or high-index groups at 4 weeks and 8 weeks. The forest plot shows the 8-week additional change from baseline in systolic blood pressure in the ultrafiltration group compared to the control group. Blood pressure change evoked by the transition in volume from low to high was similar to that from low to low. Similarly, blood pressure change evoked by the transition in volume from high to low was similar to that from high to high. Likewise, transitions in volume from low to either volume were not different from transitions from high to either volume. Thus, changes in volume state were not predictive of change in blood pressure. Abbreviations are defined as in figure 1.