Relationship Between the Severity of Exercise Induced Ischaemia and the Prevalence of Exercise Induced Calf Symptoms During Treadmill Testing With Transcutaneous Oximetry

It was hypothesised that there is a linear relationship between the severity of exercise induced calf ischaemia and the prevalence of calf claudication on a treadmill until a plateau is reached. It was expected that no pain would be present in the absence of ischaemia and all severely ischaemic calves would be symptomatic. This was a retrospective analysis of a cross sectional acquired database recording. Transcutaneous oxygen pressure (TcPO2) on the chest and on each calf was used to evaluate calf ischaemia during treadmill tests with simultaneous recording of calf pain in 7 884 subjects (15 768 calves). The minimum value of calf changes from rest minus chest changes from rest (DROPm) was calculated. Regression analyses were used to determine the correlation between the proportion of exercise induced symptoms present in the calves and each unit of DROPm values. Analysis was repeated after objective determination of the cutoff point between the linear increase and the plateau. A linear relationship was found between the degree of ischaemia and the proportion of symptomatic calves for DROPm values ranging from 0 mmHg to −28 mmHg (proportion = −0.014 × DROPm + 0.32, r = 0.961, p