Effect of lower extremity blood pressure on physical functioning in patients who have intermittent claudication

Purpose: Claudication patients' perceptions of walking impairment often influence recommendations for peripheral bypass and angioplasty. The actual relationship between lower extremity blood flow and physical functioning, however, has rarely been explicitly studied. Methods: Patients were enrolled at a visit to one of 16 vascular surgery offices and clinics that participated in a prospective outcomes study. A total of 555 patients (445 men and 110 women) with an abnormal ankle-brachial index (ABI), none of whom had had previous leg revascularization or symptoms of rest pain, skin ulcers, or gangrene, completed the SF36 Health Survey and the Peripheral Arterial Disease Walking Impairment Questionnaire (WIQ). Stepwise multiple regression analysis was used to test the statistical significance and strength of association between patients' ABI level and SF36 physical functioning (PP) and WIQ community walking distance scores, controlled for sociodemographic characteristics and the presence and severity of comorbid conditions. Results: Univariate correlations with ABI were modest but significant (PF score, r = 0.12, p = 0.004; WIQ distance score, r = 0.18, p < 0.001). ABI was a very significant predictor of both PF (b = 18.8; p = 0.001) and WIQ scores (b = 0.33; p < 0.0001) in the multiple regression analysis. Other positive predictors of PF scores were high-school graduation and male sex. Negative predictors of PP scores were heart, lung, and cerebrovascular disease; knee arthritis and chronic back pain; and enrollment at a Veterans Administration clinic rather than a private community or academic office. Conclusion: Cross-sectional findings indicate that a 0.3 improvement in ABI is associated with an average improvement of 5.6% in PF or 10.3% in WIQ distance score. However, proper selection of individual candidates for interventional therapy, that is, those patients who have lower ABIs, lower initial functioning, and fewer disabling comorbidities would be predicted to produce a much greater functional benefit. Surgeons should make a rigorous functional evaluation when recommending interventional management of claudication.