{'fraction_non_alphanumeric': 0.02170374389582203, 'fraction_numerical': 0.021432447097124253, 'mean_word_length': 5.6672694394213385, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Commentary: Alternative Approach to Successful Crossing

In 2003, two groups of investigators were the first to describe the use of percutaneous retrograde access for critical limb ischemia (CLI) in patients with prior failed antegrade revascularization attempts. Botti et al used tibial retrograde access for revascularization in 6 patients with infrapopliteal occlusions, while Spinosa et al reported using antegrade dissection in conjunction with a retrograde tibial approach in 2 patients. Since then, the retrograde tibiopedal approach for revascularization of infrainguinal chronic total occlusions (CTOs) has been utilized by experienced operators to treat severe peripheral artery disease (PAD; Rutherford categories 4–6) in patients who have had prior unsuccessful antegrade interventions and were not candidates for surgical revascularization. This approach is particularly advantageous for CLI patients for whom revascularization has been the only treatment strategy to reduce the incidence of amputation. Patients with CLI often have severe, multilevel PAD characterized by long CTOs with significant calcification in the proximal cap that deflects antegrade wires into adjacent branch vessels. As such, antegrade attempts at CTO revascularization from the contralateral or ipsilateral common femoral artery have failure rates of 20% to 40%. In cases where antegrade revascularization has failed, retrograde tibiopedal access in experienced hands and the appropriate patient population is an important avenue to achieve revascularization. Despite the increased prevalence of this technique, however, most data regarding its efficacy and safety have come from single-center studies. To address this limitation, Walker and colleagues conducted a prospective, multicenter (8 US centers and 3 European centers), observational study evaluating the technical success and short-term safety of retrograde tibiopedal access for infrainguinal CTO revascularization in 197 patients over a 1-year period. The primary purpose of the study was to establish the acute safety of tibiopedal access and to report on both the technical success of target vessel access and retrograde target lesion crossing. Of the study group, 67% had undergone a prior unsuccessful attempt at antegrade revascularization of the same occlusion, meaning that 33% of the patients included had an initial attempt at revascularization via a retrograde approach. Approximately two thirds of the patients in the study had CLI (Rutherford categories 4–6). Target vessel access (defined as “the ability to gain percutaneous entry into a tibiopedal artery in the desired location and to deliver a guidewire to facilitate introduction of a catheter”) was achieved in 93.4% of the patients (91.7% in CLI patients and 96.9% in claudicants). Retrograde target lesion crossing (“the ability to reach an infrainguinal arterial occlusion via a tibiopedal approach and to pass a wire through the proximal boundary of the occlusion”) was achieved in 79.6% (157/197; 85.3% of patients who had successful target vessel access). The authors also concluded that tibiopedal access was safe, with no major complications and few minor access site–related complications in the acute setting and within 30 days of follow-up via patient telephone interviews. The authors should be congratulated for conducting one of the largest multicenter observational studies to date examining the safety and efficacy of tibiopedal access in patients with PAD and infrainguinal CTOs. The findings of this study complement the outcomes from 665294 JETXXX10.1177/1526602816665294Journal of Endovascular TherapyShishehbor and Chenier research-article2016