Impact of routine coronary catheterization in low extremity artery disease undergoing percutaneous transluminal angioplasty: study protocol for a multi-center randomized controlled trial.

Background: The prevalence of significant obstructive coronary artery disease with complex lesions is high in patients who have low extremity artery disease (LEAD). However, intermediate- or long-term cardiovascular prognosis of LEAD patients undergoing percutaneous transluminal angioplasty (PTA) remains poor. Accordingly, prophylactic coronary revascularization may modify short- and long-term cardiovascular outcomes of LEAD patients receiving PTA. Because myocardial ischemic symptoms are often masked in LEAD and the accuracy of non-invasive stress tests is usually limited, a high-quality randomized controlled trial aimed at the investigation of the prognostic role of coronary evaluation strategies before PTA is warranted.

Methods/design: The proposed study is designed as a prospective, multi-center, open-label, superiority, randomized controlled trial. The study is conducted in high-volume centers for PTA and coronary revascularization in Taiwan. To meet the inclusion criteria, the patients must be at least 20 years old, have known LEAD, and have been admitted for elective PTA. We plan to enroll 450 participants who are randomly allocated to a routine group (routine coronary angiography without a previous non-invasive stress test before PTA) and a selective group (selective coronary angiography based on the results of non-invasive stress tests before PTA) with 1:1 ratio. Besides, we expect to enroll about 250 additional participants, who are not willing to be randomly assigned, in the registration group. The choice of revascularization procedure depends on the operator's or cardiovascular team's suggestion and the patient's decision. Clinical follow-up will be performed 30 days after PTA and every 6 months until the end of the 1-year follow-up for the last randomly assigned participant. The primary endpoint is the composite major adverse cardiac event on long-term follow-up. Pre-specified secondary and other endpoints are also evaluated. Those assessing biomarkers and clinical endpoints are all blinded after assignment to interventions.

Discussion: The results of the trial will, for the first time, support better decision-making for coronary evaluation before PTA in LEAD. If favorable, routine coronary angiography followed by revascularization will improve cardiovascular outcomes in LEAD patients undergoing PTA.

Trial Registration: ClinicalTrials.gov identifier: NCT02169258 (registered on 21 June 2014); registry name: Routine Coronary Catheterization in Low Extremity Artery Disease Undergoing Percutaneous Transluminal Angioplasty (PIROUETTE-PTA).