Systolic acceleration time as an indicator of hemodynamic severity in peripheral artery disease with medial artery calcification

Background: Ankle-brachial-index (ABI) calculation is the recommended method in diagnosing peripheral artery disease (PAD) but its use is limited due to medial artery calcification (MAC) which leads to incompressibility of lower limb arteries and results in false elevated ABI values. Measurement of systolic acceleration time (AT) by duplex ultrasound is being discussed as an alternative, but whether coexisting MAC influences AT values remains unknown. Patients and methods: In a prospective clinical study healthy subjects, patients with MAC and patients with PAD with and without MAC were examined. In all 238 participants ABI calculation for posterior tibial artery (ATP) and anterior tibial artery (ATA) was performed by continuous wave (CW) Doppler ultrasonography, followed by measurement of AT derived from velocity-time spectra of ATP, ATA, and brachial artery (AB) by colour-coded duplex sonography. We introduced an innovative parameter to quantify PAD severity: the absolute difference value of AT (DAT), calculated as the absolute difference between crural AT and brachial AT. This parameter aims to minimize confounding effects of cardiac conditions on AT measurements. Results: It was found that a coexisting MAC does not have a significant impact on AT values (p>.05). According to the findings of this study PAD is present in patients with AT >95ms (sensitivity (Se): 85%, specificity (Sp): 87%) or in patients with DAT >20ms (Se: 82%, Sp: 84%). Conclusions: Both AT and DAT are suitable quantitative parameters for PAD diagnosis and severity assessment in patients with coexisting MAC, providing valuable alternatives when ABI is unreliable.