While early findings demonstrated promising results, recent studies have proven that patients with severe emphysema derive no significant benefits from a less-invasive alternative, known as airway bypass, to surgical lung-volume reduction, known as the sham procedure. That is according to a recent study published in The Lancet.
The study reports that airway bypass failed to improve lung function or dyspnea in comparison to the sham procedure, despite the successful release of trapped air in emphysematous lung tissue. Airway bypass was developed as an alternative to surgical lung-volume reduction, which was proven to improve breathing and reduce dyspnea. However, the surgery was the cause of substantial morbidity.
Performed by broncoscopy, airway bypass calls for the surgical creation of passages in bronchial airways, followed by the placement of paclitaxel-coated stents to maintain passages’ patency. Early studies demonstrated that airway bypass maintained efficacy for six months in patients with a residual volume/total lung capacity (RV/TLC) greater than 67 percent.
Encouraging early results led to the design of a randomized, controlled trial of airway bypass in patients with severe homogenous emphysema. Investigators at 38 centers across England, Germany, Brazil and the U.S. recruited 315 patients with severe hyperinflation. The patients were then randomized 2:1 to airway bypass or sham procedure.
At the end of the trial, 30 of 208 patients in the airway bypass group demonstrated improvements of 12% or greater in forced vital capacity (FVC) and at least a one-point decrease in dyspnea score, compared to 12 of 107 in the control group. Researchers reported that in the airway bypass group, mean FVC increased from baseline to day one but then returned to baseline over the next three months.
“Although our findings showed safety and transient improvements, no sustainable benefit was recorded with airway bypass in patients with severe homogeneous emphysema,” authors concluded.