Assessment of Exercise Capacity after Lobectomy in Patients with COPD Department of Thoracic and Cardiovascular Surgery, Nara Medical University School of Medicine, Kashihara, Japan Keiji Kushibe ， MD, Takeshi Kawaguchi ， MD ， Takashi Tojo ， MD ， Makoto Takahama, MD ， Michitaka Kimura, MD ， Yoko Nagata, MD ， and Shigeki Taniguchi , MD
Background Recent studies have showed that patients with chronic obstructive pulmonary disease (COPD) lose less ventilatory capacity after lobectomy compared with those with non-COPD. Moreover, selected patients with severe emphysema have been recognized even as having an improvement in ventilatory capacity after lobectomy for lung cancer. However, change in exercise capacity, which is an important measure of quality of life, after lobectomy in patients with COPD remains unclear.
Purpose We compared the differences of ventilatory capacity and exercise capacity after lobectomy for lung cancer between COPD and non-COPD patients.
Patients The data of patients who underwent lobectomy for NSCLC from January 1995 to December 2005 were retrospectively collected. One hundred sixty-eight patients had pulmonary function tests and exercise tests on the same day before surgery. Exclusion criteria Adjuvant chemo or radiothrapy (n=15) Incapacity to quit smoking (n=2) Postoperative empyema (n=2) Severe pulmonary complications (n=6) Severe stenosis of residual bronchus (n=5) Segmental or lobar atelectasis before surgery (n=15) A tumor more than 4 cm in size (n=15) Finally, 100 patients who had pulmonary function tests and exercise tests 6 months to 1 year after surgery were enrolled .
Patients Patients were divided into 3 groups according to their preoperative severity of COPD. We adopted Global Initiative on Obstructive Lung Disease (GOLD) guidelines to classify severity of COPD. Non-COPD (N group) 71 (FEV1/FVC > 70%) Mild COPD (M group) 15 (FEV1/FVC < 70%, FEV1 80% > of predicted ) Moderate-to-severe COPD (S group) 14 (FEV1/FVC < 70%, FEV1 < 80% of predicted) Total 100 = =
Methods #. Exercise capacity was determined by an incremental exercise test on a cycle ergometer with breath-by breath analysis of gas exchange #. We compared the differences of changes in FVC, FEV1, VO 2 max , workload ( %ΔFVC, %ΔFEV, %ΔVO 2 max , %ΔW ) between the 3 groups.
a : p < 0.0001 vs N group, b : p < 0.005 vs M group. N group(n=71) M group(n=15) S group(N=14 ) %ΔFVC -14.6±10.5 -11.1±13.7 -8.6±16.3 %ΔFEV1 -14.7±11.5 -11.6±10.7 +4.7±15.8 a, b %ΔVO 2 max -9.2±12.1 -12.2±10.4 -9.7±18.3 %ΔW -9.4±15.3 -9.2 ±13.3 -6.0±34.5 Percentage change in pulmonary function and exercise capacity after operation
Preoperative FEV1% of predicted M group (n=15) S group (n=14) %ΔFEV1 r 0.19 - 0.93 p 0.48 < 0.0001 %ΔVO 2 max r - 0.22 - 0.64 p 0.42 0.01 %ΔW r - 0.29 - 0.25 p 0.27 0.39 Correlation between FEV1% of predicted and percentage change in FEV1 or exercise capacity after lobectomy in COPD patients
-20 -10 0 10 20 30 % change in FEV1 in the S group 30 40 50 60 70 80 Pre-op. FEV1% of predicted (%) in the S group (n= 14) Correlation between preop. FEV1% of predicted and percentage change in FEV1 in the S group Percentage change in FEV1 = 78.6 - 12.5 × preop. FEV1 % of predicted; R 2 = 0.86, r = - 0.93, p < 0.0001.
-40 -30 -20 -10 0 10 20 30 30 40 50 60 70 80 Pre-op. FEV1% of predicted (%) in S group % change in VO 2 max in S group Correlation between preop. FEV1% of predicted and percentage change in VO 2 max in S group Percentage change in VO 2 max = 49.3 - 0.96 × preop. FEV1% of predicted; R 2 = 0.41, r = - 0.64, p = 0.01. (n= 14)
N group M group S group %ΔVO 2 max r 0.01 0.39 0.61 p 0.93 0.14 0.02 %ΔW r 0.02 0.47 0.19 p 0.87 0.07 0.52 %ΔFEV1 Correlation between percentage change in FEV1 and percentage change in VO 2 max
Conclusion #. Moderate-to-severe COPD patients lost less FEV1 than non-COPD or mild COPD patients. #. I n the S group, patients with lower pre- operative FEV1 % of predicted had less loss in FEV1 and VO 2 max after lobectomy. #. They lost exercise capacity to the same extent as the other patients.