What is the best approach to manage intradialytic hypertension in patients with impaired renal function undergoing dialysis?

Treatment of Intradialytic Hypertension

The primary treatment for intradialytic hypertension is aggressive volume removal through dry weight reduction, even in patients who do not appear clinically volume overloaded, as bioimpedance studies demonstrate significant chronic extracellular volume excess despite small interdialytic weight gains. 1, 2

Definition and Recognition

Intradialytic hypertension is defined as a systolic blood pressure rise >10 mm Hg from pre- to post-dialysis, occurring in 10-15% of hemodialysis patients. 3, 4 This condition increases mortality risk comparable to severe intradialytic hypotension and warrants immediate intervention. 2

Primary Management Strategy: Volume Control

Dry Weight Optimization

• Gently probe the prescribed target weight downward as the first-line intervention, as patients with intradialytic hypertension typically have significant chronic extracellular volume overload despite appearing euvolemic clinically. 1, 2
• Reassess dry weight even when patients lack obvious signs of volume overload, as bioimpedance spectroscopy reveals hidden extracellular fluid excess in these patients. 2
• The long-term risks of chronic volume overload must be weighed against the potential risks of higher ultrafiltration rates. 3

Dialysis Prescription Modifications

• Increase treatment time and/or frequency (through home hemodialysis or center-based nocturnal hemodialysis) to allow more gradual volume removal and better hemodynamic stability. 1, 3
• Lowering ultrafiltration rates through longer or more frequent sessions reduces end-organ ischemia risk while achieving volume targets. 3
• Consider adding treatments rather than only lengthening existing sessions, based on patient preference and facility resources. 3

Dialysate Sodium Management

Lower dialysate sodium concentration is the only controlled intervention proven to interrupt blood pressure increases during dialysis. 2

• Reducing dialysate sodium decreases interdialytic weight gain and blood pressure, though it may increase intradialytic hypotension and cramping risk. 3, 4
• Sodium balance should be negative during hemodialysis treatment to reduce long-term interdialytic weight gain. 3
• Abandon sodium profiling procedures, as these contribute to positive sodium balance. 5
• The prescribed and delivered dialysate sodium concentrations can differ, making individualization challenging and potentially unsafe. 3

Dietary Sodium Restriction

• Restrict dietary sodium intake to 2-3 g/day with regular dietitian counseling to reduce interdialytic weight gain. 1
• Comprehensive dietary sodium management combined with dialytic sodium reduction provides maximal benefit for volume control. 5
• Reduce saline infusions used for treating intradialytic symptoms and as part of dialyzer rinsing/priming procedures. 5

Pharmacological Management

When to Initiate Medications

• If hypertension persists despite optimizing volume status through the above measures, initiate or adjust antihypertensive medications. 1
• Patients with intradialytic hypertension have persistently elevated ambulatory blood pressure requiring pharmacologic treatment. 2

Medication Selection

• Beta-blockers, particularly those with vasodilatory properties, are the preferred first-line agents as they target sympathetic nervous system overactivity and endothelial dysfunction, showing promising results in reducing both intradialytic and ambulatory blood pressure. 4
• ACE inhibitors or ARBs should be considered as they cause greater regression of left ventricular hypertrophy and may improve endothelial function. 1
• Calcium channel blockers (amlodipine) reduced cardiovascular events compared to placebo in randomized trials of hypertensive hemodialysis patients. 3, 1

Medication Timing

• Administer antihypertensive drugs preferentially at night to reduce nocturnal blood pressure surge and minimize intradialytic hypotension. 1
• Consider the dialyzability of medications when selecting agents, as non-dialyzable drugs provide more consistent blood pressure control. 1

Pathophysiological Considerations

The mechanisms driving intradialytic hypertension include:

• Chronic extracellular volume excess despite small interdialytic weight gains 2
• Intradialytic vascular resistance surges (mediators beyond endothelin-1 remain under investigation) 2
• Sympathetic nervous system and renin-angiotensin-aldosterone system overactivity 4
• Endothelial dysfunction and arterial stiffness 4
• Lower albumin and predialysis urea nitrogen levels causing small osmolarity reductions that prevent blood pressure decreases 2

Critical Pitfalls to Avoid

• Do not assume patients with small interdialytic weight gains are euvolemic—they often have significant hidden volume overload requiring aggressive dry weight reduction. 2
• Do not use high dialysate sodium to improve hemodynamic stability in these patients, as this creates a vicious cycle of sodium loading, higher interdialytic weight gain, and worsening hypertension. 6
• Do not delay volume assessment and dry weight reduction while waiting for pharmacologic interventions to take effect. 1, 2