How to manage hypertension in a patient undergoing dialysis?

Management of Hypertension in Dialysis Patients

Management of hypertension in dialysis patients requires addressing both fluid status and medication therapy, with ACE inhibitors or ARBs as first-line agents due to their cardiovascular benefits.

Pathophysiology and Assessment

Hypertension is extremely common in dialysis patients (50-60%), with volume overload being the primary driver. Proper assessment includes:

• Measuring blood pressure with appropriate cuff size in the supine position
• Monitoring predialysis, intradialytic, and postdialysis blood pressure
• Assessing for volume overload through clinical examination
• Evaluating for secondary causes in resistant cases

Treatment Algorithm

Step 1: Volume Management (Primary Intervention)

• Target dry weight optimization through:
  • Low sodium intake (2-3 g/day) with dietary counseling every 3 months 1
  • Increased ultrafiltration during dialysis sessions 1
  • Longer dialysis duration or more frequent sessions (>3 per week) 1
  • Intradialytic sodium modeling to minimize hypotension 1

Step 2: Pharmacological Management

1. First-line therapy: ACE inhibitors or ARBs 1, 2

   • Preferred due to regression of left ventricular hypertrophy
   • Reduction of sympathetic nerve activity
   • Improvement of endothelial function
   • ARBs may be more potent than ACE inhibitors for LVH reduction 2
   • Example: Lisinopril 2.5mg post-dialysis (alternate day or once-weekly) 2
   • Monitor for hyperkalemia 3

2. Second-line therapy: Calcium channel blockers 2, 4

   • Minimal elimination by dialysis
   • Associated with decreased cardiovascular mortality 2
   • Example: Amlodipine 5-10mg once daily 2

3. Third-line therapy: Beta-blockers 2, 4

   • Particularly beneficial in patients with coronary artery disease
   • Consider dialyzability (non-dialyzable options like carvedilol preferred) 2

4. Fourth-line therapy: Other agents

   • Alpha-blockers or central-acting agents like clonidine 4
   • Minoxidil for severe resistant hypertension 4

Blood Pressure Targets

• Predialysis BP goal: <140/90 mmHg 1, 2
• Postdialysis BP goal: <130/80 mmHg 1, 2
• Avoid excessive BP reduction (<110/70 mmHg) which increases mortality risk 5

Medication Administration Considerations

• Administer antihypertensive drugs preferentially at night to reduce nocturnal BP surge 1
• Consider dialyzability of medications 1, 2:
  • Non-dialyzable: carvedilol, labetalol, most CCBs, ARBs
  • Dialyzable: some ACE inhibitors, atenolol
  • For dialyzable medications, administer post-dialysis

Special Considerations

Peritoneal Dialysis Patients

• Maximize peritoneal ultrafiltration and urine output 1
• Strategies include:
  • Using icodextrin for long dwells
  • Shortening dwell time with glucose-based solutions
  • Using diuretics if residual kidney function exists

Resistant Hypertension

• Defined as BP >140/90 mmHg despite dry weight achievement and three antihypertensive agents 1, 2
• Consider secondary causes of hypertension
• Consider switching to peritoneal dialysis if hemodialysis fails 1
• Surgical or embolic nephrectomy as last resort 1

Intradialytic Hypertension

• Affects 10-15% of dialysis patients 6
• Management includes strict volume control and low dialysate sodium 6
• Beta-blockers with vasodilatory properties may be particularly effective 6

Common Pitfalls to Avoid

1. Neglecting volume control before intensifying medication therapy
2. Failing to adjust medications for dialysis schedule
3. Administering dialyzable medications before dialysis sessions
4. Excessive BP reduction leading to intradialytic hypotension
5. Not monitoring for hyperkalemia with ACE inhibitors/ARBs
6. Using diuretics in anuric patients (ineffective unless substantial residual kidney function exists) 2

By following this structured approach that prioritizes volume control and appropriate medication selection, hypertension in dialysis patients can be effectively managed to reduce cardiovascular morbidity and mortality.