What are the findings and recommendations of the landmark trial on Bronchoscopic Thermal Vapor Ablation (BTVA) for severe emphysema?

Bronchoscopic Thermal Vapor Ablation (BTVA) for Severe Emphysema: Landmark Trial Findings

Bronchoscopic Thermal Vapor Ablation (BTVA) has demonstrated clinically meaningful improvements in lung function, exercise capacity, and quality of life in patients with upper lobe-predominant emphysema, with the STEP-UP trial serving as the landmark study showing a 14.7% improvement in FEV1 and 9.7-point reduction in SGRQ-C at 6 months compared to standard medical management. 1

Key Findings from the Landmark STEP-UP Trial

The STEP-UP (Sequential Staged Treatment of Emphysema with Upper Lobe Predominance) trial is the definitive landmark study for BTVA. This multicenter, randomized controlled trial published in 2016 demonstrated:

• Primary efficacy outcomes at 6 months:

  • 14.7% relative improvement in FEV1 compared to control group (p<0.0001)
  • 9.7-point improvement in SGRQ-C quality of life score (p=0.0021)
  • Targeted segmental approach preserved less diseased segments while treating more diseased ones 1

• Patient selection criteria:

  • Upper lobe-predominant emphysema
  • FEV1 between 20-45% predicted
  • Substantial hyperinflation
  • Post-rehabilitation 6MWT >140m 1

Mechanism and Procedure

BTVA works by delivering heated water vapor to targeted emphysematous segments, causing a localized inflammatory response that leads to tissue and volume reduction. This approach:

• Can be performed regardless of collateral ventilation status (unlike valve-based approaches)
• Targets the most diseased segments with highest emphysema index
• Is performed under deep sedation or general anesthesia 2

Clinical Benefits

Meta-analysis data confirms significant improvements at 6 months in:

• Forced expiratory volume in 1 second (FEV1)
• Residual volume (RV) reduction
• Total lung capacity (TLC)
• 6-minute walk distance (6MWD)
• St George's Respiratory Questionnaire (SGRQ) scores

Notably, most improvements occur within the first 3 months post-procedure 3

Safety Considerations

The most common adverse events in the STEP-UP trial were:

• COPD exacerbations (24% in treatment group vs. 4% in control)
• One treatment-related death occurred 84 days post-procedure
• No pneumothorax events within 30 days of treatment 1

Meta-analysis confirms COPD exacerbations (RR: 12.49) and pneumonia (RR: 9.49) as the most common complications at 6 months 3

Patient Selection Algorithm

For optimal outcomes with BTVA:

1. Confirm diagnosis: Upper lobe-predominant emphysema
2. Verify lung function parameters:
   • FEV1: 20-45% predicted
   • RV: >175% predicted
   • DLCO: ≥20% predicted
3. Assess heterogeneity: Confirm higher emphysema index in target segments
4. Ensure adequate functional status: Post-rehabilitation 6MWT >140m
5. Rule out contraindications: Active infection, severe cardiac disease 2, 1

Current Status in Guidelines

While the 2017 GOLD guidelines mention bronchoscopic approaches to lung volume reduction, they note that "additional data are needed to define the optimal patient population to receive a specific bronchoscopic lung volume technique and to compare the long-term durability of improvements in functional or physiological performance to LVRS relative to side effects." 4

Future Directions

The ongoing BENTO trial (expected completion in 2024) aims to further validate BTVA in the German healthcare system, with quality of life as the primary endpoint and a larger sample size of 224 patients 5.