What are the recommended SLED (Slow Low-Efficiency Dialysis) settings for a patient with Heart Failure with Reduced Ejection Fraction (HFrEF) undergoing hemodialysis?

SLED Settings for HFrEF Patients

For HFrEF patients requiring renal replacement therapy, peritoneal dialysis or more frequent/longer duration hemodialysis sessions are preferred over conventional hemodialysis due to slower ultrafiltration rates that minimize intradialytic hypotension and allow better volume control, which is critical for maintaining guideline-directed medical therapy (GDMT). 1

Dialysis Modality Selection

Preferred Approaches for HFrEF

• Peritoneal dialysis should be strongly considered as first-line renal replacement therapy in HFrEF patients because it provides continuous, gentle ultrafiltration that avoids the hemodynamic stress of intermittent hemodialysis 1
• SLED (Slow Low-Efficiency Dialysis) or extended hemodialysis sessions are superior to conventional hemodialysis when peritoneal dialysis is not feasible, as slower ultrafiltration rates (typically 100-200 mL/hour vs 500-1000 mL/hour in conventional HD) reduce cardiovascular stress 1
• The slower fluid removal with SLED/extended sessions allows better preservation of cardiac output and blood pressure, which is essential for tolerating life-saving HFrEF medications 1

Critical Rationale

• Approximately 20% of dialysis patients have HFrEF, and this population faces exceptionally high mortality rates that are compounded by intolerance to GDMT due to hemodynamic instability from aggressive ultrafiltration 1
• Conventional hemodialysis causes rapid volume shifts that trigger intradialytic hypotension, forcing clinicians to inappropriately discontinue or down-titrate GDMT medications that provide 73% mortality reduction over 2 years 2, 1

Specific SLED Parameters for HFrEF

Session Duration and Frequency

• SLED sessions should run 6-12 hours per session, 5-7 days per week to achieve adequate clearance while maintaining hemodynamic stability 1
• Longer, more frequent sessions are better tolerated than shorter, less frequent sessions in HFrEF patients 1

Ultrafiltration Rate

• Target ultrafiltration rate should not exceed 10-13 mL/kg/hour (approximately 100-200 mL/hour for most patients) to minimize intradialytic hypotension 1
• This slower rate allows the vascular refilling rate to match fluid removal, preventing hypovolemia and hypotension 1

Dialysate Composition Modifications

Temperature

• Use cooled dialysate (35-36°C instead of standard 37°C) as this reduces intradialytic hypotension by promoting peripheral vasoconstriction and maintaining blood pressure 1
• Dialysate cooling has demonstrated benefits specifically in hemodynamically unstable patients 1

Calcium Concentration

• Consider higher dialysate calcium concentration (3.0-3.5 mEq/L) as this improves cardiac contractility and vascular tone, reducing hypotensive episodes 1
• Higher calcium dialysate has shown benefits in maintaining blood pressure during dialysis 1

Vascular Access Considerations

Protecting Future Options

• Strongly consider leadless pacemakers and subcutaneous ICDs rather than transvenous devices in HFrEF patients who may require dialysis, as transvenous leads can compromise future hemodialysis access options 1
• This is particularly important because many HFrEF patients will eventually require ICD or CRT-D devices for primary prevention (LVEF ≤35% despite optimal therapy) 3, 2

Medication Management During SLED

Maintaining GDMT During Dialysis

The single most important principle: Never discontinue or down-titrate GDMT for asymptomatic hypotension or modest changes in renal function during dialysis optimization. 3

SGLT2 Inhibitors (First Priority)

• Continue SGLT2 inhibitors (dapagliflozin or empagliflozin) even on dialysis as they provide mortality and hospitalization benefits independent of their glucose-lowering or diuretic effects 2, 4
• Dapagliflozin can be used with eGFR ≥20 mL/min/1.73 m², empagliflozin with eGFR ≥30 mL/min/1.73 m² 2, 4
• These agents have minimal blood pressure effects (only -1.50 mmHg in patients with baseline SBP 95-110 mmHg) 2

Beta-Blockers (Second Priority)

• Continue evidence-based beta-blockers (carvedilol, metoprolol succinate, or bisoprolol) throughout dialysis as they reduce mortality by at least 20% and sudden cardiac death 3, 2
• Only bisoprolol may accumulate in renal impairment, but patients should still be titrated to target dose (10 mg daily) or maximally tolerated dose 4
• If carvedilol causes excessive hypotension during SLED, switch to metoprolol succinate or bisoprolol rather than discontinuing beta-blockade 3

Renin-Angiotensin System Inhibition (Third Priority)

• Sacubitril/valsartan (ARNI) is NOT recommended with eGFR <30 mL/min/1.73 m², so most dialysis patients cannot use this agent 4
• ACE inhibitors or ARBs should be continued in dialysis patients despite limited trial data, as they are commonly used and generally well-tolerated 1, 4
• Monitor closely for hyperkalemia and worsening hemodynamics, but do not discontinue for modest changes alone 4, 5

Mineralocorticoid Receptor Antagonists (Fourth Priority)

• MRAs (spironolactone or eplerenone) require eGFR ≥30 mL/min/1.73 m², so most dialysis patients cannot use these agents 3, 4
• If eGFR is borderline (25-30 mL/min/1.73 m²), start with very low doses (spironolactone 6.25-12.5 mg daily or every other day) with intensive potassium monitoring 4

Diuretic Management

• Reduce or discontinue loop diuretics once on dialysis as volume control is achieved through ultrafiltration 3
• This diuretic reduction often improves blood pressure tolerance and allows better GDMT optimization 3

Common Pitfalls to Avoid

Critical Errors in HFrEF Dialysis Management

• Never discontinue GDMT medications solely due to low blood pressure readings if the patient has adequate perfusion (warm extremities, normal mentation, adequate urine output if not anuric) 3
• Never use conventional 3-4 hour hemodialysis sessions in HFrEF patients as rapid ultrafiltration causes intradialytic hypotension that forces inappropriate GDMT discontinuation 1
• Never attribute hypotension to GDMT without first evaluating for other causes including excessive ultrafiltration, dialysate temperature, infection, or non-HF medications like alpha-blockers 3, 2

Monitoring Requirements

• Check blood pressure, heart rate, and volume status before and after each SLED session to guide ultrafiltration goals and medication adjustments 1
• Monitor potassium and renal function weekly initially, then monthly when stable on GDMT during dialysis 4, 5
• Accept modest increases in creatinine (up to 30% above baseline) if the patient is clinically stable, as this does not indicate harm and should not prompt GDMT discontinuation 5

Evidence Limitations and Clinical Judgment

Knowledge Gaps

• High-quality randomized trial data for GDMT in dialysis patients is essentially non-existent because dialysis patients were systematically excluded from major HFrEF trials 1, 5
• No trials have specifically evaluated SLED vs conventional hemodialysis in HFrEF, so recommendations are based on physiologic principles and observational data 1
• ICD and CRT-D devices have not shown consistent benefit in the limited dialysis studies, unlike in non-dialysis HFrEF populations, though this may reflect the competing risk of non-arrhythmic death 1

Real-World Application

• Despite limited evidence, beta-blockers and ACE inhibitors/ARBs are commonly used in dialysis patients with HFrEF and appear reasonably well-tolerated in clinical practice 1
• The benefits of GDMT in non-dialysis CKD patients (eGFR 30-60 mL/min/1.73 m²) are well-established, with most drug classes safe and effective up to CKD stage 3B 5
• SGLT2 inhibitors show safety and efficacy even in CKD stage 4 (eGFR 15-30 mL/min/1.73 m²), making them the most evidence-based GDMT option for advanced kidney disease 5