Cryospray beat sham bronchoscopy on symptom scores, at a pneumothorax cost

Design

prospective sham-controlled randomised trial, 2:1 allocation, 12-month follow-up

Population

203 patients with chronic obstructive pulmonary disease and chronic bronchitis

Primary outcome

safety and change in St George's Respiratory Questionnaire and COPD Assessment Test scores

Effect

SGRQ difference -5.9 (95% CI -11.6 to -0.2); CAT -3.4 (-5.8 to -1.0); pneumothorax after 3.6% of treatments

SPRAY-CB randomised 203 patients with chronic obstructive pulmonary disease and chronic bronchitis 2:1 to two bronchoscopies with therapeutic mucus clearance either with or without metered liquid nitrogen cryospray to the bronchial airways, 30 to 60 days apart, and followed them for 12 months. Both arms had the bronchoscopy, which is what makes the comparison meaningful.

St George's Respiratory Questionnaire improved 5.9 points more with treatment (95% CI -11.6 to -0.2, p = 0.042) and the COPD Assessment Test by 3.4 points (-5.8 to -1.0, p = 0.005). Exacerbations of any severity occurred in 70.6% against 67.2% - no difference. Severe exacerbations were 21.3% against 26.9%. Periprocedural pneumothorax occurred after 3.6% of treatments delivered, ten events in 276. Eight deaths occurred, six in the treated arm and two in the sham arm, none adjudicated as device- or procedure-related.

The symptom benefit is real and sham-controlled, which places it above most bronchoscopic interventions for chronic bronchitis. It is also modest: 5.9 points on St George's is around the four-point threshold usually called clinically important, and the confidence interval reaches -0.2. Set against that, a one in 28 pneumothorax rate per treatment, twice. This is a device available in few centres and in none in India; the reason to know about it is that a patient may ask.

• Both arms underwent bronchoscopy, so the comparison isolates the cryospray rather than the procedure.
• Symptom score gains were modest and their confidence interval nearly reached zero.
• Overall exacerbation rates did not differ; only severe exacerbations trended lower.
• Pneumothorax followed 3.6% of treatments, and each patient received two.
• Not available in India; relevant for answering a patient who has read about it.

Why it matters

Chronic bronchitis has almost no sham-controlled evidence behind any procedure, and this is a rare exception rather than a large effect.

Don't overread it

Symptom scores, not exacerbations or lung function - the primary benefit shown is how patients felt.

The statistics, in plain English

A 5.9-point gain on St George's with a confidence interval running to -0.2 means the benefit is statistically present but could be almost nothing; the four-point mark usually taken as clinically important sits inside that interval rather than below it. The exacerbation comparison is the one that would have mattered most and it did not separate, which is the usual pattern for symptom-focused bronchoscopic interventions.

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