IntraVascular UltraSound After Below-The-Knee Endovascular Therapy: an Observational Pilot Study

ObjectiveRestenosis limits the benefit of below-the-knee (BTK) endovascular therapy (EVT). Restenosis may be attributable to limited information from digital subtraction angiography. A promising alternative is intravascular ultrasound (IVUS). However, data regarding the association between post-EVT IVUS-detected lesions and the risk for future major adverse limb events (MALE) after BTK EVT are scarce.DesignProspective single-arm observational pilot study.MethodsPatients scheduled for BTK EVT were eligible. Altogether, 50 patients were included after informed consent. IVUS was performed in treated BTK vessels to analyze vessel characteristics and, if present, lesions. Lesions were defined as; significant stenoses (≥50%), substantial vessel wall irregularities (highly calcified multisided sharp wall irregularities without significant stenosis and over a longer track post-PTA), any dissections, and incorrect stenting. Follow-up included duplex ultrasound (DUS) after 3, 6 weeks, and 3 and 6 months after EVT by trained independent nurses blinded to IVUS findings. Primary endpoint was MALE, including restenosis/occlusions and major amputation.ResultsIn total, 33/50 (66%) participants had at least one lesion following IVUS. Compared to the group without any lesions, no difference in baseline characteristics was found. Lesions contained mostly significant stenosis (52%) or wall irregularities (20%). Within 6 months, 28 (56%) participants experienced MALE, including 23 restenosis/occlusion. In total, 21/28 (75%) participants with MALE had a lesion on IVUS imaging. Participants with MALE had a higher incidence of any lesions on IVUS compared with the no-lesion group (64% vs 41%), leading to a sensitivity of 0.75 and specificity of 0.45.ConclusionThis study suggests a good sensitivity for IVUS in detecting post-treatment lesions leading to MALE. However, a well-powered study is warranted to confirm these results. Ultimately, a randomized trial should assess the effect of interventions for IVUS-detected lesions post-EVT on reduction of risk of future MALE. However, the first needs are standardized reporting definitions, categorization of IVUS-detected lesions, and standardization of operating procedures.