The ABI: Standardizing Measurements & Interpretations

The ABI: Standardizing Measurements & Interpretations

When the ankle-brachial index (ABI) emerged in 1950, it was initially proposed for use as a noninvasive diagnostic tool for lower-extremity peripheral artery disease (PAD). Since then, studies have shown that the ABI is an indicator of atherosclerosis at other vascular sites, making it a useful prognostic marker for cardiovascular events and functional impairment, even in the absence of symptoms of PAD. In an issue of Circulation, the American Heart Association (AHA) released a scientific statement with standardized recommendations for measuring and monitoring the ABI. The recommendations provide protocols and thresholds for use in PAD and cardiovascular risk prediction, according to Michael H. Criqui, MD, MPH, FAHA, who co-chaired the writing committee that developed the scientific statement. “A lack of standards for measuring and calculating the ABI can lead to discrepancies that can significantly impact both prevention and treatment of cardiovascular disease,” he says. “The estimated prevalence of PAD may vary substantially according to the mode of ABI calculation.” Reducing Variation in ABI Technique Recent studies have revealed that techniques for performing the ABI vary from clinician to clinician. Several variables have been identified, including the position of patients during measurement, the sizes of the arm and leg cuffs, and the method of pulse detection over the brachial artery and at the ankles. Other variables include whether the arm and ankle pressures were measured bilaterally, which ankle pulses were used, and whether a single measure or replicate measures were obtained. Several recommendations have been endorsed by the AHA for measuring the ABI (Table 1). “These recommendations can serve as a guide to ensure that clinicians are measuring the ABI...

A Consensus on Cath Lab Patient Flow

The atmosphere of a catheterization laboratory poses challenges to maintaining and prioritizing high-quality care and patient safety. Despite these challenges, healthcare providers performing procedures in the cath lab are expected to maintain appropriate communication, clinical management, documentation, and universal protocol. A Uniform Standard for Cath Labs My colleagues and I, on behalf of the Society for Cardiovascular Angiography and Interventions (SCAI), published a clinical expert consensus statement on best practices in the cardiac cath lab in the March 20, 2012 online issue of Catheterization and Cardiovascular Interventions. Previous standards from the American College of Cardiology and SCAI have focused on how to set up a cath lab and run it as an administrator, but the new consensus statement focuses on the processes of patient flow. Following cardiac catheterization, careful patient monitoring is crucial during the hospital stay. Several vital components should be reviewed and documented prior to performing cardiac catheterization. Because percutaneous procedures are often complex, patients should be well informed about the procedure and their possible outcomes. When patients arrive at the cath lab, it’s recommended that a checklist be filled out documenting informed consent, history and physical exam information, medications, and allergies. It’s also important to document each patient’s candidacy for drug-eluting stents as well as sedation and anesthesia, their healthcare proxy status, and results of laboratory evaluations that are needed prior to the procedure. It’s highly recommended that use of any checklists cover all the nuances that can be easily missed if they’re not properly recorded. The SCAI recommends that best practices during cardiac catheterization include a thorough review of patient medical records, access site concerns,...