Vascular elastography: a novel method to characterize occluded lower limb arteries prior to endovascular therapy.

Purpose: To examine the effectiveness of vascular elastography (VE) for the assessment of totally occluded lower limb arteries prior to endovascular treatment (EVT).

Methods: Of 812 consecutive patients who underwent EVT between April 2010 and April 2012, VE was used to evaluate the hardness of chronic total occlusions of the femoropopliteal segment prior to EVT in 65 consecutive patients (48 men; mean 73.9 years, range 63-86). Elastograms of the CTOs proximally and distally were scored using a 5-point scale, and outcomes in limbs with hard lesions (VE score 0-2) were compared to those with soft lesions (VE score 3-4) according to lesion length. The interventionists who performed the endovascular procedures were not informed of the VE score results.

Results: CTO characteristics could be evaluated in all cases. A VE score ≤2 was found in 14 of the 23 lesions <150 mm in length. A flexible guidewire was sufficient for recanalization in more of the soft lesions than in the hard lesions [6/9 vs. 2/14, respectively]. In 39 lesions >150 mm, a VE score of 3 was recorded in most lesions proximally, while lesions distally were hard in many cases (VE score 1 or 2). A flexible guidewire alone was sufficient in many soft CTOs (8/13, p<0.01). In 16 cases, hard calcified plaque was indicated by difficulty in penetrating the lesion even with a stiff guidewire; all these cases had a VE score of 1 or 2. A retrograde approach was required only in hard CTOs (p<0.01). The procedure time was significantly longer for the hard lesion group (152.9±63.2 vs. 87.0±29.8 minutes, p=0.001). In 11 in-stent occlusions, only VE scores of 3 (n=4) or 4 (n=7) were recorded, indicating soft thrombus, which was aspirated under distal protection in 7 cases.

Conclusion: VE may be a useful method for determining the hardness of CTO lesions noninvasively before endovascular therapy, providing information that can help plan the procedure.