Vessel Diameter Evaluated by Intravascular Ultrasound Versus Angiography

Although reference vessel diameter (RVD) is conveniently measured by angiography during femoropopliteal (FP) endovascular therapy (EVT) in clinical practice, angiography will potentially underestimate RVD. On the other hand, intravascular ultrasound (IVUS) can measure RVD precisely. The aim of this study was to reveal the difference between angiography- and IVUS-assessed RVD in patients undergoing FP-EVT for symptomatic peripheral artery disease (PAD).

We analyzed a prospective and multicenter database including 1967 limbs of 1725 patients with symptomatic PAD undergoing IVUS-supported FP-EVT. The study outcome measure was the difference between IVUS- and angiography-assessed distal RVD (ΔRVD), calculated as angiography-assessed RVD subtracted from IVUS-assessed RVD. The clinically important difference was defined as 1 mm or larger.

IVUS-assessed RVD was significantly larger than angiography-assessed RVD (6.0±1.0 mm vs 5.0±1.0 mm; p<0.001). Mean ΔRVD (IVUS- minus angiography-assessed RVD) was 0.98 mm (95% CI, 0.94-1.03 mm). ΔRVD was 1 mm or larger in 48.8% (46.5%-51.0%) of the whole population. Multivariate analysis demonstrated that small angiography-assessed RVD, angiography-assessed bilateral calcification, and history of stent implantation were significantly associated with an increasing risk of ΔRVD ≥1mm, whereas presence of chronic total occlusion (CTO) was significantly associated with a decreasing risk of ΔRVD ≥1 mm.

The current study revealed the difference between angiography-assessed reference lumen diameter and IVUS-assessed reference EEM diameter of FP lesions. About half of population had ΔRVD ≥1 mm. IVUS-assessed RVD was more likely to be different by angiography in cases with small vessels, CTO, bilateral calcification, and history of stent implantation.