Should an echocardiogram be obtained before titrating adaptive servo‑ventilation (ASV) to ensure the left ventricular ejection fraction (LVEF) is not ≤45%?

Should an Echocardiogram Be Obtained Before ASV Titration?

Yes, an echocardiogram must be obtained before initiating adaptive servo-ventilation (ASV) to confirm that the left ventricular ejection fraction (LVEF) is not ≤45%, as ASV is contraindicated in patients with predominant central sleep apnea and LVEF ≤45%.

Critical Safety Contraindication

• ASV is absolutely contraindicated in patients with predominant central sleep apnea (CSA) and LVEF ≤45%, based on evidence showing increased mortality risk in this specific population 1, 2
• The contraindication applies specifically to patients with both reduced LVEF (≤45%) and predominant CSA (>50% of respiratory events being central) 1, 2
• In clinical practice, 16% of cardiac patients and 9% of respirology patients receiving ASV fell into this contraindicated category, highlighting the importance of pre-treatment screening 1

Mandatory Pre-Titration Assessment

• Echocardiography must be performed before ASV initiation to measure LVEF and exclude the contraindicated patient population 1, 2
• The echocardiogram should assess:
  • LVEF (must be >45% if predominant CSA is present) 1, 2
  • Left ventricular dimensions and wall thickness to characterize cardiac structure 2
  • Stroke volume if optimizing ASV settings based on hemodynamic response 3

Clinical Algorithm for ASV Candidacy

Step 1: Obtain diagnostic polysomnography

• Determine apnea-hypopnea index (AHI ≥15 required for treatment) 4
• Classify sleep-disordered breathing as predominantly obstructive (≥50% obstructive events) versus central (>50% central events) 1, 4

Step 2: Perform echocardiography

• Measure LVEF using standard 2D echocardiography 1, 2
• If LVEF ≤45% and predominant CSA is present → ASV is contraindicated 1, 2
• If LVEF >45% or if obstructive sleep apnea predominates → ASV may be considered 1, 4

Step 3: Risk stratification

• Patients with severe heart failure (low LVEF, severe HF symptoms, CSA) have significantly higher 3-month event rates (13.9% vs 1.5-5% in other groups) 2
• Consider alternative therapies in high-risk populations even when not absolutely contraindicated 2

Special Considerations for ASV Optimization

• Novel approach: Some centers optimize ASV settings using echocardiographic assessment of stroke volume during titration to maximize hemodynamic benefit 3
• This method involves adjusting ASV parameters while monitoring stroke volume changes on echocardiography to identify settings that improve cardiac output 3
• In one case report, this optimization approach showed beneficial long-term outcomes in a patient with LVEF ~20%, though this contradicts the general contraindication and should be interpreted cautiously 3

Common Pitfalls to Avoid

• Do not assume LVEF based on clinical assessment alone; measurement variability and clinical examination are insufficient to exclude the contraindicated range 1, 2
• Do not initiate ASV in patients with treatment-emergent CSA on CPAP without first confirming LVEF >45%, as this represents a common indication for ASV but requires cardiac screening 1
• Do not rely on outdated echocardiograms; obtain current imaging within a reasonable timeframe before ASV initiation, as LVEF can change with disease progression or medical therapy 2

Monitoring After ASV Initiation

• Clinical usage of ASV should be monitored with diligence even in non-contraindicated populations 1
• Consider repeat echocardiography if clinical heart failure worsens during ASV therapy 2
• The ADVENT-HF trial is ongoing to better define which heart failure subgroups benefit from ASV treatment 4