Comparison of angiographic and intravascular ultrasound vessel measurements in infra-popliteal endovascular interventions: The below-the-knee calibration study.

Overview

abstract

BACKGROUND: Endovascular revascularization (ER) via percutaneous transluminal angioplasty (PTA) and stenting are viable options for revascularization in below-the-knee (BTK) peripheral arterial disease. Two-dimensional angiography has been the standard of practice for estimating vessel size and selecting treatment devices during ER. However, in other vascular territories, intravascular ultrasound (IVUS) offers better visualization of the lumen dimensions. PURPOSE: To compare angiographic and intravascular ultrasound reference vessel (lumen) measurements in below-the-knee peripheral artery interventions. METHODS: 20 consecutive patients were enrolled in the BTK Calibration study from 2 sites in the United States and Australia. Patients with at least one diseased segment in a native infra-popliteal artery (below-the-knee) and a clinical indication for endovascular therapy (EVT) were included with no limitations with regards to vessel diameter or lesion length. Digital subtraction angiography and intravascular ultrasound imaging were collected pre-and post-percutaneous transluminal angioplasty and images were sent to an independent Core lab for standardized quantitative analysis of the normal-looking reference vessel dimensions when available. The results were presented as least square means with 95% confidence intervals and a p-value of <0.05 was considered as significant. RESULTS: The overall (N = 19) mean reference vessel diameter for QVA was 2.98 ± 1.24 vs. 3.47 ± 0.72 for IVUS (mean difference was -0.50, (95% CI: -0.80, -0.20; p = 0.14). As expected in the proximal segments (N = 12), the mean reference vessel diameters were larger: for QVA was 3.17 ± 1.34 vs. 3.55 ± 0.76 in IVUS, (mean difference was -0.38, (95% CI:-0.79,0.03; p = 0.40); while in the distal segments (N = 7), mean reference vessel diameters were smaller: for QVA was 2.64 ± 1.06 vs. 3.33 ± 0.67 in IVUS, (mean difference was -0.69, (95% CI:-1.04,-0.34; p = 0.17). We observed a greater degree of acute gain in cases where the treatment balloon size correlated with the IVUS measured reference size. CONCLUSION: Angiography underestimates infrapopliteal reference vessel lumen size even when quantitatively assessed. Adjunctive IVUS imaging use in guiding BTK procedures could help ensure adequate sizing and possibly impact immediate post-procedure indices.