T he ankle-brachial index (ABI) is the ratio of the systolic blood pressure (SBP) measured at the ankle to that measured at the brachial artery. Originally described by Winsor 1 in 1950, this index was initially proposed for the noninvasive diagnosis of lower-extremity peripheral artery disease (PAD). 2,3 Later, it was shown that the ABI is an indicator of atherosclerosis at other vascular sites and can serve as a prognostic marker for cardiovascular events and functional impairment, even in the absence of symptoms of PAD. 4 -6 Rationale for Standardization of the ABIThe current lack of standards for measurement and calculation of the ABI leads to discrepant results with significant impact from clinical, public health, and economic standpoints. Indeed, the estimated prevalence of PAD may vary substantially according to the mode of ABI calculation. [7][8][9] In a review of 100 randomly selected reports using the ABI, multiple variations in technique were identified, including the position of the patient during measurement, the sizes of the arm and leg cuffs, the location of the cuff on the extremity, the method of pulse detection over the brachial artery and at the ankles, whether the arm and ankle pressures were measured bilaterally, which ankle pulses were used, and whether a single or replicate measures were obtained. 10 There is controversy about what ABI threshold should be used to diagnose PAD. The ABI threshold most commonly used is Յ0.90 based on studies reporting Ͼ90% sensitivity and specificity to detect PAD compared with angiography. 2,3 These studies were limited in that they included mostly older white men with PAD or who were at high risk for PAD and compared them with a younger healthy group. A recent metaanalysis of 8 studies of diverse populations, including diabetic patients, confirmed a high specificity but lower sensitivity (at best Ͻ80%) than that reported in earlier studies. 11 Similar to other vascular markers such as carotid intimamedia thickness 12 or coronary artery calcium score, 13 standardization of the techniques used to measure the ABI and the calculation and interpretation of its values is necessary. Aims and ScopeThe goals for this document are to provide a comprehensive review of the relevant literature on the measurement of the The American Heart Association makes every effort to avoid any actual or potential conflicts of interest that may arise as a result of an outside relationship or a personal, professional, or business interest of a member of the writing panel. Specifically, all members of the writing group are required to complete and submit a Disclosure Questionnaire showing all such relationships that might be perceived as real or potential conflicts of interest.This statement was approved by the American Heart Association Science Advisory and Coordinating Committee on September 10, 2012. A copy of the document is available at http://my.americanheart.org/statements by selecting either the "By Topic" link or the "By Publication Date" link. To purchase additional repri...

The endothelium holds a pivotal role in cardiovascular health and disease. Assessment of its function was until recently limited to experimental designs due to its location. The advent of novel techniques has facilitated testing on a more detailed basis, with focus on distinct pathways. This review presents available in-vivo and ex-vivo methods for evaluating endothelial function with special focus on more recent ones. The diagnostic modalities covered include assessment of epicardial and microvascular coronary endothelial function, local vasodilation by venous occlusion plethysmography and flow-mediated dilatation, arterial pulse wave analysis and pulse amplitude tonometry, microvascular blood flow by laser Doppler flowmetry, biochemical markers and bioassays, measurement of endothelial-derived microparticles and progenitor cells, and glycocalyx measurements. Insights and practical information on the theoretical basis, methodological aspects, and clinical application in various disease states are discussed. The ability of these methods to detect endothelial dysfunction before overt cardiovascular disease manifests make them attractive clinical tools for prevention and rehabilitation. METHODS FOR EVALUATING ENDOTHELIAL FUNCTION. A POSITION STATEMENT FROM THE EUROPEAN SOCIETY OF CARDI-OLOGY WORKING GROUP ON PERIPHERAL CIRCULATION. John Venous occlusion plethysmographyVenous occlusion plethysmography (VOP), established more than 100 years ago, is the longest living method for investigating blood flow in humans. Flow-mediated dilatationConduit vessels respond to alterations in blood flow by increasing vessel diameter via an endothelial dependent mechanism. 20,21 The flow-mediated dilatation (FMD)technique measures changes in conduit artery diameter by ultrasound. This response has been shown to reflect local bioactivity of endothelial-derived NO. 22 MethodologyThe brachial artery is most often imaged (online Supplemental Figure 2). FMD studies are performed in a quiet temperature controlled room while subjects are lying supine for >10 min prior to image acquisition. A straight, non-branching segment of the brachial artery above the antecubital fossa is imaged in the longitudinal plane with the ultrasound probe securely fixed using a stereotactic clamp. This permits fine adjustments in the coronal and sagittal planes. A blood pressure cuff is placed 1-2 cm below the antecubital fossa and inflated to supra-systolic pressure. 23 After cuff release, reactive hyperaemia results and is quantified using Doppler. The arterial diameter is recorded at end diastole using electrocardiographic gating during image acquisition, to determine the response of the conduit artery to increase in flow. 24 Changes in the arterial diameter are assessed using commercial digital edge detection software. Pulse wave analysisThe arterial waveform contains important information about the stiffness of the large arteries and amount of wave reflection within the arterial system. 32 Wave reflection occurs at sites of impedance mismatc...

Background-We sought to identify whether transcutaneous oxygen tension (tcPO 2 ) measurements could be used to noninvasively detect lesions in the arterial network supplying blood flow to the hypogastric circulation. Methods and Results-A study was undertaken in vascular patients with suspected (PC, nϭ43) and not with suspected (NPC, nϭ34) proximal ischemia. TcPO 2 was measured on both buttocks and with a chest reference electrode. Arteriography on the right or left side was positive for stenoses (Ն75%) or occlusion of one or more of the following arteries: the aorta, the common iliac arteries, or the internal iliac arteries.

Background-The maximal walking distance (MWD) performed on a treadmill test remains the "gold standard" in estimating the walking capacity of patients who have peripheral arterial disease with intermittent claudication, although treadmills are not accessible to most physicians. We hypothesized that global positioning system (GPS) recordings could monitor community-based outdoor walking and provide valid information on walking capacity in patients with peripheral arterial disease. Methods and Results-We studied 24 patients (6 women

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