The SAFARI technique in a patient with peripheral arterial occlusive disease

Clinical History

Diabetic patient with peripheral arterial occlusive disease and right heel ulceration.

Imaging Findings

Doppler ultrasound of the right leg revealed: severe stenosis of the distal portion of the superficial femoral artery (SFa), occlusion of the mid and distal portion of the popliteal artery (PA), and a post-stenotic flow pattern at the tibio-peroneal trunk (TPT) and anterior tibial artery (ATa). A slow flow was detected in the posterior tibial artery (PTa) (Fig.1).
The patient underwent digital subtraction arteriography that showed occlusion of the distal SFa extended to the PA. Collateral vessels recanalized the PTa and, retrogradely, the TPT, the ATa (which was occluded distally), and the peroneal artery. The dorsal pedal artery was poorly displayed, while the plantar pedal artery was patent (Fig. 2).
Percutaneous subintimal revascularization was attempted using Bolia’s technique. The re-entry site was achieved at the ATa, but we failed to re-enter the TPT (Fig. 3).
The patient returned to attempt a second revascularization procedure using the SAFARI ('subintimal arterial flossing with antegrade-retrograde intervention') technique.
The PTa was punctured under ultrasound guidance using an 18-G needle (Fig. 4). A guidewire was advanced retrogradely in the PTa and, subintimally, through the occlusion of the TPT up to the SFa, where it was captured with a gooseneck snare and driven up to the femoral access site.
Multiple angioplasties of the TPT, PTa, peroneal artery, and perforating branches for the dorsal pedal artery were performed (Fig. 5). A catheter balloon was also dilated at the puncture site of the PTa to ensure haemostasis.
The control angiogram showed patency of the treated arteries (Fig. 6).

Discussion

Lower limb ischemia is one of the most common complications in patients with long-lasting diabetes mellitus.
Subcritical limb ischemia usually responds well to medical treatment alone and allows to postpone surgical therapy. In contrast, patients with critical limb ischemia who are treated with medical therapy alone have limb salvage rates as low as 5%, thus warranting percutaneous revascularization.
Surgical treatment of critical limb ischemia in diabetic patients is often contraindicated because of coexisting diseases and frequent distal vascular involvement. Percutaneous endovascular revascularization using intraluminal or subintimal techniques may be a valid alternative to surgical bypass in patients at risk for limb loss and not suitable for surgery. In fact, percutaneous revascularization has proved to be highly effective in the treatment of critical limb ischemia in terms of success rate, clinical outcome, and procedure-related complications.
Subintimal revascularization consists of creating a new lumen between the medial and the intimal vascular layers by advancing a guidewire until a reentry site is found at the distal patent portion of the vessel. This new lumen is remodelled with multiple angioplasties. This technique is preferred in chronic, long occlusions (>5 cm), in which the intraluminal technique is associated with poor patency rates.
However, subintimal revascularization alone is associated with a high rate of technical failure (13-24%), particularly in the case of heavily calcified vessels and occlusions involving the trifurcation. The main cause of failure is the difficulty to precisely guide the dissection into the best distal runoff vessel and achieve the re-entry site in the target vessel.
In selected patients, these problems have successfully been overcome by a new technique described by Spinosa et al. in 2005, called SAFARI (subintimal arterial flossing with antegrade-retrograde intervention).
With SAFARI, the best distal runoff vessel is punctured at the ankle under ultrasound guidance and a guidewire is retrogradely advanced through the obstructed tract, creating a new lumen. Re-entry in a proximal larger vessel (such as the SFa) is then usually more feasible and can be secured by capturing the guidewire with a gooseneck snare introduced through the SFa access (Fig. 7). The guidewire is then extracted at the femoral access site. The new lumen is remodelled with antegrade angioplasties.
Spinosa et al. concluded that the SAFARI technique can be useful for completing subintimal revascularization in the event of failure to reenter the distal true lumen from an antegrade approach or when there is limited distal target artery available for reentry. This improves technical success in the performance of subintimal revascularization, resulting in limb salvage rates as high as 90% at 6 months. Gandini et al. reported the use of the SAFARI technique in 4 out of 104 patients with critical limb ischemia and concluded that it should be adopted as a standard procedure in the case of long vascular occlusions involving the trifurcation.
Although larger series are to be evaluated, the SAFARI technique can be a valid option in selected patients with critical limb ischemia in whom standard endovascular or subintimal techniques fail to provide valid revascularization.

Differential Diagnosis List

Final Diagnosis

Limb arterial revascularization using Bolia’s and SAFARI techniques.

URL:	https://www.eurorad.org/case/8271
DOI:	10.1594/EURORAD/CASE.8271
ISSN:	1563-4086