Interobserver and intraobserver reproducibility of peripheral blood and oxygen pressure measurements in the assessment of lower extremity arterial disease

Introduction: Peripheral blood pressure measurements play a prominent role in the diagnosis and follow-up of patients with peripheral vascular disease s. Toe pressure of the hallux (TP1) and second toe (TP2) and transcutaneous oxygen pressure (TCPO2) measurements are becoming more important. The ankl e/brachial pressure index (ABPI) is known to be a reliable parameter, but t he toe pressure and TCPO2 are evaluated less thoroughly. Therefore, we eval uated the reproducibility of TP1, TP2, TCPO2, ABPI, ankle pressure (AP), an d brachial pressure (BP). Patients and Methods: In 54 patients with various stages of peripheral vasc ular disease, the intraobserver and interobserver reproducibility of BP, AP , ABPI, TPL, TP2, and TCPO2 was investigated by calculating the repeatabili ty coefficient (RC) and the intraclass correlation coefficient (ICC) and by using Bland-Altman plots. Results: The intraobserver and interobserver reproducibility at 1 day and a fter 1 week of BP, AP, ABPI, and TP1 was substantial and comparable (ICC ra nge, 0.80-0.99), except for the Br after 1 week. The TP2 and TCPO2 were les s reproducible (ICC range, 0.62-0.98). The interobserver RC of BP was 31 mm Hg; of AP, 44 mm Hg; of ABPI, 27%; of TPL, 41 mm Hg; of TP2, 67 mm Hg; and of TCPO2; 30 mm Hg. The difference plot showed that the observer variabili ty was equally distributed across the range of pressure in all measurements . Conclusion: The BP, AP, ABPI, and TP1 have a substantial intraobserver and interobserver reproducibility, whereas TP2 and TCPO2 show worse reproducibi lity Especially when low values (or values around a cutoff value) are measu red, the RC should be taken into account, and repetition of the measurement is advocated.