Left ventricular hypertrophy: is hyperphosphatemia among dialysis patients a risk factor?

Cardiovascular disease occurs in ESRD patients at rates that are far higher than is seen in the general population, and cardiovascular deaths account for the majority of deaths among dialysis patients. Abnormal mineral metabolism is a novel cardiovascular risk factor among dialysis patients. Recently published results demonstrated that even with good control of BP and anemia, conventional hemodialysis is associated with significant left ventricular hypertrophy (LVH); however, daily hemodialysis was associated with a significant reduction in LV mass index (LVMI). Furthermore, it was shown that control of serum phosphorus correlates with the reduction in LVMI. These data suggest a novel mechanism for the deleterious effect of elevated serum phosphorus on cardiovascular outcomes among hemodialysis patients: LVH. Other investigators have noted an association of hyperphosphatemia and LVH; however, this study was the first to demonstrate that improvement in serum phosphorus is associated with reduction in LVM. In addition, it is shown that daily hemodialysis is an effective modality in improving serum phosphorus through significantly improved phosphorus removal. Elevated serum phosphorus leads to vascular calcification, which can lead to LVH by decreasing vascular compliance. However, our study showed an improvement in LVMI during a 12-mo period. Because vascular calcification is unlikely to remit over this time period, it is proposed that serum phosphorus has a reversible, cardiotoxic effect that leads to LVH that can be reversed successfully with good control of serum phosphorus.