Chapter 9: Cardiovascular Outcomes and Home Hemodialysis

INTRODUCTION

Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD), and has been reported to be more than twice as likely to develop in patients with CKD compared to the general Medicare population.¹ CVD prevalence increases with progression of CKD, and is the leading cause of death in individuals with advanced CKD, particularly among those requiring dialysis. Left ventricular hypertrophy (LVH) is a maladaptive response to volume/pressure overload that leads to cardiomyopathy. LVH is quite prevalent in end-stage kidney disease (ESKD), with reported rates as high as 90%, and thus is an important predictor of CVD morbidity and mortality.² Anemia, mineral bone metabolism, uremia/inflammation, and most importantly hypertension (HTN) have all been implicated in the development of LVH.³ As a consequence, the overall rates of CVD-related hospitalizations and mortality remain high in ESKD, despite a slight reduction over the past decade, pointing toward the need for interventions that improve CVD outcomes in this vulnerable patient population.¹

The majority of patients with ESKD in the United States undergo in-center thrice-weekly hemodialysis (HD). This regimen of HD, typically 3 to 4 hours per session, is suboptimal as it is associated with significant hemodynamic instability, which leads to unintended clinical consequences. Many patients are in a chronic fluid overload state, which is also associated with worse CVD outcomes. Achieving euvolemia is challenging due to intradialytic hypotension (IDH) which is observed in at least 25% of outpatient dialysis sessions.⁴ IDH occurs as a result of aggressive ultrafiltration (UF) in a relatively short period of time and the mismatch which occurs between the rates of UF and plasma capillary refill. The downstream effects lead to tremendous stress on the heart and other vulnerable vascular beds (such as those in the brain, gastrointestinal tract, and kidney). Foley et al. showed approximately 23% higher risk of death on the first day after the long interdialytic interval, and higher cardiovascular hospitalization rates after this long period.⁵ This high-risk interval has been termed by some as the “killer gap,” given its association with higher rates of cardiovascular-related hospitalizations and mortality (Figure 9-1). Intensive HD or more frequent HD offers an alternative for prescribers with a gentler option in the form of either short daily or extended nocturnal treatments, which reduces the interdialytic weight gain and promotes more favorable rates of fluid removal. Given the logistics and limitations of performing more frequent HD in the dialysis clinic setting, home hemodialysis (HHD) has emerged as a viable option to achieve better clinical cardiovascular targets. Given this premise, multiple studies on more frequent HD have demonstrated improvement in cardiovascular outcomes in the ESKD population.^6–10

In this chapter, we review the epidemiology and the pathophysiology of LVH, an independent predictor of CVD, in ...