What determines the complication rate in high-risk chronic obstructive pulmonary disease patients: surgery or pulmonary function?

We read with interest the article by Shafiek et al. [1] about the analysis of the parameters during cardiopulmonary exercise testing (CPET) that could predict complications after thoracic surgery in patients affected by moderate–severe chronic obstructive pulmonary disease (COPD) according to the GOLD criteria [2].

They described other parameters beyond the maximal oxygen consumption (VO₂ max) that could indicate a high risk of mortality and long-term disability for major anatomical resection. In particular, they found that the baseline minute ventilation to carbon dioxide output (VE/VCO₂) slope of >35 (at maximal exercise) was strongly associated with the probability of mortality and postoperative complications (hazard ratio 5.14) with a survival probability of 40% after 1 year of follow-up. We think that this should be a parameter in patient selection, to avoid surgery for high-risk patients or to plan different, tailored strategies.

In fact, we noticed some focus points in their paper that could be analysed to indicate different approaches to this group of high-risk patients.

First of all, they performed surgery only via thoracotomy, whereas, especially in COPD patients, video-assisted thoracic surgery (VATS) is indicated in relationship to fewer postoperative overall and pulmonary complications than thoracotomy [3]. VATS also permits advantages in chest tube duration, pain control and quick mobilization of the patient, so it is suggested and preferable for early-stage, non-small-cell lung cancer (NSCLC) [4].

Second, they report a high number of complications in patients who underwent pneumonectomy, and we think that this is an important bias because this is a very stressful and high-risk surgery for the fragile patients included in this report.

On the other hand, the authors presented no differences in 1-year survival in the patients who underwent non-surgical therapy, whereas in the surgery group, 37% of patients had poor 1-year survival secondary to their cancer stage and 45% had poor survival due to the high VE/VCO₂ slope of >35.

On the basis of these findings, maybe patient selection should be done differently, investigating two alternative approaches.

The first strategy could involve the patient in a minimally invasive approach, starting with preoperative respiratory physiotherapy and planning VATS, with strict selection of candidates excluding cancers with mediastinal spread or need of extended surgery like pneumonectomy, preferring parenchyma-saving surgery like segmentectomy. This care programme should continue also in the postoperative period, with early mobilization, intensive physiotherapy and using prophylactic, non-invasive ventilation to avoid complications.

The other way may suggest alternative treatments like Stereotactic Body Radiation Therapy (SBRT) or other target therapies for high-risk patients, excluding patients with unfavourable stage or inadequate cardiopulmonary function from an aggressive approach, even if data in the literature are not clear about the efficacy of these treatments [4].

We think that the reported cut-off, according to the previously reported experiences [5], could really indicate the appropriate strategy for severe COPD patients. Differentiating who could be fit for a minimally invasive approach, from patients really unfit for surgery that could have benefited from a non-surgical treatment.

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