Functional claudication distance: a reliable and valid measurement to assess functional limitation in patients with intermittent claudication

BACKGROUND: Disease severity and functional impairment in patients with intermittent claudication is usually quantified by the measurement of pain-free walking distance (intermittent claudication distance, ICD) and maximal walking distance (absolute claudication distance, ACD). However, the distance at which a patient would prefer to stop because of claudication pain seems a definition that is more correspondent with the actual daily life walking distance. We conducted a study in which the distance a patient prefers to stop was defined as the functional claudication distance (FCD), and estimated the reliability and validity of this measurement. METHODS: In this clinical validity study we included patients with intermittent claudication, following a supervised exercise therapy program. The first study part consisted of two standardised treadmill tests. During each test ICD, FCD and ACD were determined. Primary endpoint was the reliability as represented by the calculated intra-class correlation coefficients. In the second study part patients performed a standardised treadmill test and filled out the Rand-36 questionnaire. Spearman's rho was calculated to assess validity. RESULTS: The intra-class correlation coefficients of ICD, FCD and ACD were 0.940, 0.959, and 0.975 respectively. FCD correlated significantly with five out of nine domains, namely physical function (rho = 0.571), physical role (rho = 0.532), vitality (rho = 0.416), pain (rho = 0.416) and health change (rho = 0.414). CONCLUSION: FCD is a reliable and valid measurement for determining functional capacity in trained patients with intermittent claudication. Furthermore it seems that FCD better reflects the actual functional impairment. In future studies, FCD could be used alongside ICD and ACD

Reliability of treadmill testing in peripheral arterial disease: a meta-regression analysis

A meta-regression analysis was conducted to identify the most reliable treadmill protocol for the assessment of patients with peripheral arterial disease (PAD).status: publishe

Pocket Doppler and vascular laboratory equipment yield comparable results for ankle brachial index measurement

<p>Abstract</p> <p>Background</p> <p>The ankle brachial index (ABI) is a well-established tool for screening and diagnosis of peripheral arterial disease (PAD). In this study we assessed the validity of ABI determination using a pocket Doppler device compared with automatic vascular laboratory measurement in patients suspected of PAD.</p> <p>Methods</p> <p>Consecutive patients with symptoms of PAD referred for ABI measurement between December 2006 and August 2007 were included. Resting ABI was determined with a pocket Doppler, followed by ABI measurement with automatic vascular laboratory equipment, performed by an experienced vascular technician. The leg with the lowest ABI was used for analysis.</p> <p>Results</p> <p>From 99 patients the mean resting ABI was 0.80 measured with the pocket Doppler and 0.85 measured with vascular laboratory equipment. A Bland-Altman plot demonstrated great correspondence between the two methods. The mean difference between the two methods was 0.05 (P < .001). Multivariate linear regression analysis showed no dependency of the difference on either the average measured ABI or affected or unaffected leg.</p> <p>Conclusion</p> <p>Since the small, albeit statistically significant, difference between the two methods is not clinically relevant, our study demonstrates that ABI measurements with pocket Doppler and vascular laboratory equipment yield comparable results and can replace each other. Results support the use of the pocket Doppler for screening of PAD, allowing initiation of cardiovascular risk factor management in primary care, provided that the equipment operator is experienced.</p

Automated plethysmographic measurement of the ankle-brachial index: a comparison with the doppler ultrasound method

The ankle-brachial index is widely regarded as a pivotal tool for the diagnosis and quantification of peripheral arterial disease. It is, however, plagued by issues relating to its time consuming nature and the skills required to undertake its measurement using the gold standard Doppler ultrasound method. Automated ankle-brachial index measurement devices aim to address such issues; this study aimed to compare the performance of such a device with the Doppler method. Three hundred and eighty participants, with risk factors for cardiovascular disease (mean age: 64, 57% male), underwent ankle-brachial index measurement firstly with a plethysmographic device followed by the Doppler method. The mean difference between the two methods was 0.016±0.1, 95% limits of agreement:±0.2. Sensitivity for detection of peripheral arterial disease, as defined by Doppler ankle-brachial indexless than or equal to0.9, was 70%, specificity 96%, accuracy 94%. A receiver operating curve revealed an area under the curve of.96, with a 1.04 plethysmographic ankle-brachial index cutoff for optimal sensitivity (98%) and specificity (75%). Automated measurements were significantly faster than Doppler measurements (7 min 55 s vs. 17 min 45 s, respectively, P <0.01). Although is it unclear if the plethysmographic device has sufficient diagnostic accuracy to be used as a stand alone test for the diagnosis of peripheral arterial disease, it is concluded that it can be used as a fast and amenable method of identifying people who require further arterial assessment; the higher cutoff point of 1.04 should be used for this purpose