Roshen Mathew, MD, DAABIP, discusses STABLE, in which diagnostic yield was 86.8% with breath-hold vs 92.2% with conventional ventilation.
Standardized breath-hold ventilation did not improve strict diagnostic yield during robotic bronchoscopy for
Respiratory motion and CT-to-body divergence remain important sources of localization error during robotic bronchoscopy, and breath-hold ventilation has been proposed to stabilize the target and improve image registration.¹ Prospective randomized evidence supporting the approach has been limited.¹ The trial used strict diagnostic yield as its primary endpoint, in line with the American Thoracic Society/American College of Chest Physicians (ATS/ACCP) research statement on advanced bronchoscopy outcomes.¹˒²
“Our greatest challenge with robotic bronchoscopy, or peripheral bronchoscopy in general, is CT-to-body divergence, and motion of the peripheral target with breath is a big challenge in the lung,” said Roshen Mathew, MD, DAABIP, director of interventional pulmonology at WVU Medicine Camden Clark Medical Center. Mathew told HCPLive the investigators hypothesized breath-hold ventilation would improve diagnostic yield.
The Study of Tool-lesion Alignment and Breath-hold Ventilation in Robotic Bronchoscopy for Peripheral Lung LEsions (STABLE) was a prospective randomized trial using the Noah Galaxy Robotic Bronchoscopy System with integrated augmented fluoroscopy (AF) and C-arm-based augmented tomosynthesis (CABT).¹ Patients were randomized by computer-generated simple randomization to standardized end-inspiratory breath-hold or conventional ventilation.¹ All procedures incorporated real-time AF/CABT imaging, with tool-position confirmation and correction before tissue sampling.¹
Of 117 randomized patients, 53 received breath-hold and 64 received conventional ventilation. Strict diagnostic yield was 89.7% across all procedures, with no significant difference between breath-hold and conventional ventilation (86.8% vs 92.2%; P =.338).¹ Successful lesion localization was 98.1% versus 95.3% (P =.625), and tool-in-lesion (TIL) positioning was achieved in 62.3% versus 64.1% (P =.841).¹
Imaging-confirmed TIL or tool-touching-lesion (TTL) positioning was achieved in 97.4% of procedures.¹ With more than 1 year of ongoing follow-up, diagnostic accuracy was 93.2%.¹
“Once you have a robot, and you have an integrated imaging workflow ... then adding the breath hold really doesn’t make much of a difference,” Mathew said. “Once you achieve tool-in-lesion confirmation with integrated imaging, and also with augmented fluoro, which actually helps you make sure your tool is actually in 3 planes aligned always, then there is really no difference when you do breath hold.”
Independent of ventilation strategy, diagnostic yield showed a graded relationship with tool position. Yield was 0% with no tool-lesion relationship (NTL), 85.0% with TTL, and 95.9% with TIL.¹ TIL showed a trend toward greater diagnostic yield than TTL (OR, 4.18; 95% CI, 0.98-17.7; P =.064), and both TIL and TTL were significantly associated with greater yield than NTL (P <.001 and P =.007, respectively).¹
Radiation exposure, procedural characteristics, and complication rates were comparable between groups.¹ Pneumothorax requiring chest tube placement occurred in 0 of 53 patients (0%) in the breath-hold group and 2 of 64 (3.1%) in the conventional ventilation group (P =.50).¹
Mathew noted robotic platforms have improved diagnostic yield in prior studies, though the addition of static cone-beam imaging did not raise yield as much as expected. STABLE sought to identify which remaining procedural variables could further improve outcomes once a robotic platform and integrated imaging are in place.
The investigators concluded routine breath-hold ventilation may not be necessary during AF/CABT-guided robotic bronchoscopy, and strategies optimizing real-time TIL positioning appear to have a greater influence on yield.¹ Mathew acknowledged the trial’s limitations, including its single-center design.
“You probably need larger numbers to verify it,” Mathew said. “I think the signal we got is breath-hold ventilation probably is not the way to go.”
Editors note: Reported disclosures for Matthew include Noah Medical Corporation & Ethicon.
References
