Chapter 13: Special Populations and Home Hemodialysis

INTRODUCTION

Home hemodialysis (HHD) and more frequent (or intensive) HHD have several advantages over thrice-weekly in-center hemodialysis (conventional hemodialysis [CHD]).¹ Certain patient populations have specific medical indications for intensive hemodialysis (HD) dosing (>12 hours of HD per week), and HHD provides the flexibility to tailor the HD prescription to the patient's needs. The aim of this chapter is to discuss specific patient populations that may benefit from more intense HD at home.

CARDIOVASCULAR INDICATIONS FOR INTENSIVE HEMODIALYSIS AT HOME

Patients with end-stage kidney disease (ESKD) have much higher cardiovascular mortality rates than the general population. In fact, according to the United States Renal Data System (USRDS), younger patients (40 to 44 years) started on CHD have a strikingly short average lifespan of only 8 years.² More frequent HHD has been shown to reverse left ventricular hypertrophy (LVH), improve blood pressure control, augment endothelial dependent vasodilatation, and restore nocturnal heart rate variability.³ Additionally, more frequent HHD in the form of nocturnal hemodialysis (NHD) has been shown to normalize phosphorus levels and lower total peripheral resistance.^4,5 Taken together, patients who have increased cardiovascular burden (e.g., refractory hypertension [HTN] and LVH) should consider intensive HD as a unique therapeutic option.⁶

[For more information, see Chapters 7 and 9.]

Resistant Hypertension

Reaching euvolemia and normalizing blood pressure remains a common challenge in patients on CHD. Up to 80% of patients on HD have been reported to be hypertensive.⁷ Salt and extracellular volume overload are highly prevalent in patients with chronic kidney disease (CKD) even prior to reaching ESKD. Enhanced filling pressure leads to increased cardiac output via the Frank-Starling mechanism, thereby elevating arterial pressure. Elevated total peripheral resistance has also been described previously as occurring through the following mechanisms⁸:

1. Decreased bioavailability of vasodilatory mediators such as nitric oxide in the uremic environment,

2. Increased arterial stiffness facilitated by vascular calcification, and

3. Elevations in vasoconstrictors such as angiotensin II and norepinephrine.

Better blood pressure control is one of the most consistent findings in more frequent HHD, which obviates the need for removal of large volumes in a short time. Up to 75% of patients had normal blood pressure while on short daily HHD in one study.⁹ Interestingly, while improved blood pressure has been reported in both modalities (nocturnal and short daily HHD), the mechanisms leading to these findings may be different. In short daily HHD, patients saw a significant decrease in extracellular volume, suggesting that improved volume control was the main reason for lower blood pressure. In contrast, blood pressure decreased in nocturnal HHD despite the nadir of extracellular volume remaining unchanged. In this study, brachial artery responsiveness improved after 2 months on nocturnal HHD, indicative of reduced peripheral resistance.⁵ Potential mechanisms for decreased peripheral vascular resistance in nocturnal HHD include restoration ...