Bronchoscopic metered cryospray improved symptom scores in COPD with chronic bronchitis, with a procedural pneumothorax risk

Design

Prospective, randomised (2:1), sham-controlled trial of metered cryospray

Population

203 people with COPD and chronic bronchitis (136 treated, 67 sham)

Primary outcome

Safety and effectiveness at 12 months, including total SGRQ and CAT scores

Effect

SGRQ difference -5.9 (95% CI -11.6 to -0.2; P = 0.042); CAT -3.4 (-5.8 to -1.0)

SPRAY-CB randomised 203 people with COPD and chronic bronchitis 2:1 to two bronchoscopies with therapeutic mucus clearance, with or without metered cryospray (liquid nitrogen delivered to the airways), 30 to 60 days apart. Controls had a sham procedure. Outcomes were assessed 12 months after treatment.

The cryospray group improved more on the total St George's Respiratory Questionnaire (difference -5.9, 95% CI -11.6 to -0.2; P = 0.042) and the COPD Assessment Test (-3.4, -5.8 to -1.0; P = 0.005). Exacerbations of any severity were similar (70.6% vs 67.2%), with fewer severe exacerbations numerically (21.3% vs 26.9%). Pneumothorax occurred in 3.6% of treatments (10 of 276). There were eight deaths (4.3% vs 2.9%), none judged related to the device or procedure.

The SGRQ interval comes close to zero, the severe exacerbation difference was not tested as a primary end point, and the device is a procedure with a recognised complication. It is an option under study for selected patients, and it does not replace inhaled therapy, vaccination, pulmonary rehabilitation or smoking cessation.

• Cryospray is a device procedure under study and not a first-line treatment for chronic bronchitis.
• SGRQ improved by 5.9 points more than sham, with a confidence interval close to zero.
• Pneumothorax occurred in 3.6% of treatments; this belongs in any consent discussion.
• Optimise inhaled therapy, vaccination, rehabilitation and smoking cessation first.

Why it matters

It is a sham-controlled test of a procedure aimed at the chronic bronchitis phenotype of COPD.

Don't overread it

Exacerbation differences were numerical and not the primary end point, and 12 months does not establish durability.

The statistics, in plain English

An interval of -11.6 to -0.2 on the SGRQ means the true benefit could be anywhere from almost nothing to a fairly large improvement. The result is statistically significant but only just.

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