Prediction of claudication pain from clinical measurements obtained at rest

The ability to predict claudication pain during single-stage (S) and progressive (P) treadmill protocols from clinical measurements obtained at rest was examined. Peripheral hemodynamic measurements from the more severely diseased lower limb and medical history data were obtained from 56 claudicant patients during supine rest immediately preceding S (1.5 mph and 7.5% grade) and P (2 mph, 0% grade with 2% increase every 2 min) treadmill protocols. Distance walked to onset of claudication pain (CPD) and to maximal pain (MPD) during both protocols were recorded. The claudication distances during the S protocol were not correlated with either the peripheral hemodynamic or medical history variables. In contrast, CPD and MPD during the P protocol were predicted (P < 0.05) by ankle/brachial systolic blood pressure index (ABI) (quadratic relationship), laterality of claudication pain (1 = unilateral, 2 = bilateral), and gender (1 = female, 2 = male) from the following regression equations: CDP(m) = 159.9 - (321.8 x ABI) + (445.6 x ABI2) - (93.5 x laterality) + (99.0 x gender), R = 0.74, R2 = 0.55, adjusted R2 = 0.53, SEE = 110.5, P< 0.0001; and MPD (m) = 83.1 + (195.0 x ABI) + (174.0 x ABI2) - (76.4 x laterality) + (114.2 x gender), R = 0.76, R2 = 0.58, adjusted R2 = 0.55, SEE = 138.3, P< 0.0001. It is concluded that the regression equations for the prediction of CPD and MPD may be used to quickly estimate the functional severity of peripheral vascular occlusive disease in clinical settings where treadmill testing is not feasible or is impractical.