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Exercise testing in patients with a normal ABI and an abnormal lowest ABI.
D. Armstrong1, D. Brouillard1, U. Jurt1, C. Tobin1, M. Matangi1- (1) Kingston Heart Clinic, Kingston, Canada
Purpose. Of our PAD testing, 2,184 have normal ABIs bilaterally (0.90-1.30). In 246 (11.3%) of these normals the other "lowest ABI" is abnormal (<0.90). This occurs in 1 ankle (8.8%) or both ankles (2.5%). The "lowest ABI" is the ratio of the lowest ankle systolic pressure divided by the highest brachial systolic pressure. Post-exercise ABI measurements may be a method of detecting abnormal lower limb perfusion in this group. The purpose of this study is to compare 4 groups, see Table 1 for group definitions. Methods. Our database was searched for patients who had undergone post-exercise measurement of ABI and fitted into one of the 4 groups. Patients were exercised for 5 minutes at 10 degrees and a speed of 2mph. The test was stopped for symptoms or when the 5 minutes was completed. The ankle pressures and highest brachial pressure were measured at rest and post-exercise. Five post-exercise measurements were recorded as quickly as possible. An abnormal ABI response to exercise was any fall to <0.90 in the first or second post-exercise measurement. ANOVA and Chi-squared analysis were used where appropriate. Results. Group 1 comprised 120 patients and 11 had an abnormal response (9.2%). Group 2 comprised 172 patients and 75 had an abnormal response (43.6%). Group 3 comprised 12 patients and 9 had an abnormal response (75%), Group 4 comprised 61 patients and 50 had an abnormal response (82%), P<0.0001 using Chi-squared analysis. Conclusions. Post-exercise ABIs should be performed in all patients with normal resting ABIs (0.90-1.30) in both legs and either leg symptoms, femoral bruits or an abnormal lowest ABI, and in the case of the abnormal lowest ABI groups, even in the absence of leg symptoms or femoral bruits.
Gp1= All 4 ABIs normal, no leg symptoms, no femoral bruits. Gp2 All 4 ABIs normal ± leg symptoms ± femoral bruits. Gp3 Normal ABI, abnormal lowest ABI, no symptoms, no femoral bruits. Gp4 Normal ABI abnormal lowest ABI ± symptoms ± femoral bruits.