Peripheral arterial disease: an underestimated aetiology of exercise intolerance in chronic obstructive pulmonary disease patients.

OBJECTIVE

To assess the prevalence of peripheral arterial disease and its implications for exercise limitation in chronic obstructive pulmonary disease (COPD) patients.

METHOD

One hundred and fifty-one moderate-to-severe COPD patients (forced expiratory volume in 1 s: 37+/-6 SD% predicted) and 73 healthy age-matched control individuals (divided into 31 smokers and 42 nonsmokers) participated in this study. All COPD patients were either exsmokers or current smokers and their tobacco-smoking history was similar to that of healthy smokers. To evaluate the existence of arterial disease, lower limb perfusion pressure impairment was assessed using the ankle brachial index, whereas arterial stiffness was assessed by the pulse wave velocity (PWV). The definition of peripheral arterial disease required an ankle brachial index value of 0.90 or less, whereas the PWV increment was considered to be a direct witness of arterial stiffness increase. A 6-min walk test was performed to assess physical exercise capacity.

RESULTS

Prevalence of peripheral arterial disease was higher in COPD patients than in healthy participants (81+/-3 SD; 49+/-5 SD and 9+/-2 SD%, respectively, in COPD, healthy smokers and nonsmokers). PWV mean values were significantly higher in COPD patients compared with healthy smokers and nonsmokers (10.3+/-2.1 SD m/s; 9.2+/-1.3 SD m/s and 8.7+/-2.2 SD m/s, respectively). The distance covered during the 6-min-walk test was associated positively with the degree of peripheral arterial disease (r=0.78; P=0.05) and negatively with the PWV values (r=-0.74; P=0.05). Not only tobacco-smoking history but also COPD severity was shown to influence these associations.

CONCLUSION

The effect of peripheral arterial disease on exercise intolerance in COPD seems to be considerable. Therefore, COPD patients participating in a pulmonary rehabilitation programme should profit from a systematic search for arterial disease. Arterial dysfunction has to be taken into account in the multidisciplinary treatment of these patients.