RE: Regarding the ‘‘SAFARI’’ Technique: a Word of Caution

To the Editor, We read with great interest the letter from Lupattelli et al. [1]. We agree with the authors that when using the combined technique of subintimal arterial flossing with anteroretrograde intervention (SAFARI) in patients with critical limb ischemia (CLI) presenting with long-segment occlusions involving the superficial femoral, popliteal, and trifurcation arteries, it should be implemented with care and only in selected patients. Since the initial published experience by Spinosa et al. [2], we have performed this procedure on 45 limbs in patients with CLI. All patients had tissue loss (Rutherford 5/6) and were deemed not to have a reasonable operative option by an experienced vascular surgeon (i.e., no venous conduit, high risk for general anesthesia, or large wound at the distal bypass site). The median length of the occlusions in these 45 limbs was 30 cm. Technical success in providing in-line flow to the foot was achieved in 41 of 45 (90%) treated limbs. Access into the distal vessels was performed under ultrasound guidance using local anesthesia and a micropuncture set (Cook, Bloomington, IN, or AngioDynamics, Glen Falls, NY). The limb-salvage rate for technically successful cases was 78%, 71%, 57%, and 57% at 6, 12, 24, and 48 months, respectively [3]. In our experience, we did not encounter arterial dissection or thrombosis at the access site or distal emboli. The target vessels were studied carefully with ultrasound before retrograde arterial puncture, and a disease-free segment of the pedal or peroneal artery was accessed. The distal access site catheter diameter (i.e., the inner dilator of the transition dilator in a micropuncture set) was limited to 3F. Intra-arterial vasodilators, such as nitroglycerin, were liberally administered into the distal artery to minimize vasospasm. Appropriate anticoagulation is essential until in-line flow is established. Severe stenoses distal to the retrograde access site were treated through the antegrade access to maximize outflow. When the distal retrograde access was no longer needed, the catheter was removed, and light pressure was applied to the access site for 5 min, which was usually sufficient to obtain hemostasis. Open surgical access for the distal vessels was not necessary. Indeed, surgical access creates excess tissue trauma in these poorly perfused limbs, and we have not needed to employ open distal access in any of our patients. We agree that this procedure can be time-consuming in some cases, but use of the SAFARI technique has resulted in fairly rapid guidewire traversal of long-segment occlusion in patients in whom antegrade attempts to cross occlusions have proven to be difficult or have failed. In addition, the patients undergoing such procedures often have multiple comorbidities, including renal insufficiency and severe cardiac disease, and must be closely monitored during a potentially lengthy and stressful procedure. However, the stress on the cardiovascular system associated with the use of conscious sedation is much less than that associated with the general or epidural anesthesia used during open surgical revascularization. In our practice, the SAFARI technique is used primarily in patients with CLI when the main therapeutic alternative would be a major amputation or a high-risk distal bypass. Antegrade traversal of the occluded infrainguinal segments, most often from an ipsilateral antegrade approach, S. S. Sabri (&) J. F. Angle A. H. Matsumoto Department of Radiology, University of Virginia, Charlottesville, VA, USA e-mail: ss2bp@virginia.edu