Novel endovascular technique may prevent amputation in "no-option" limb ischemia patients: NEJM study

Key treatments for chronic limb-threatening ischemia include guideline-directed medical therapy to address risk factors for systemic cardiovascular disease and revascularization of the affected leg to restore straight-line arterial flow to the foot and facilitate wound healing.

Two major revascularization – surgical bypass and minimally invasive endovascular techniques approaches can be pursued in patients with limb ischemia. Both these techniques connect artery to artery and require a downstream target of an unobstructed vessel in the lower leg or foot on which to “land” the treatment. However, in as many as 15 to 20% of persons with chronic limb-threatening ischemia, there is no landing point, owing to diffuse distal arterial disease, which precludes conventional revascularization.

It is for these specific no-option patients that Shishehbor and colleagues present their findings from the PROMISE II study in the latest issue of NEJM.

The novel concept:

In this technique, arterial flow in the leg is connected to the downstream deep-venous segments instead of to an arterial target, thereby reversing flow in the veins and perfusing the distal limb through the venous rather than the arterial system.

One catheter is advanced in the artery from the groin to the knee; another catheter is advanced in the vein from the foot to the knee. At this rendezvous point behind the knee, the artery and vein are mechanically connected with the use of a needle, a guide wire, and covered stents. This creates a straight pathway from the upper-leg arterial system to the venous circulation of the foot, effectively “arterializing” the venous flow and providing oxygenated blood to the ischemic tissues.

The salient features of study were:

1. In the PROMISE II study, the investigators prospectively enrolled 105 patients with advanced chronic limb-threatening ischemia who were deemed to have no revascularization options and to face a likely prospect of major amputation.
2. The primary end point of this nonrandomized, single-group study was 6-month amputation-free survival, defined as freedom from above-ankle amputation or death from any cause.
3. The investigators reported procedural success in 99% of the patients and 6-month amputation-free survival in 66.1%, which exceeded the prespecified performance goal of 54.0%.
4. Complete wound healing was noted in 25% of the patients and partial healing in half.
5. Outcomes were worse for patients who were receiving dialysis than for those without renal failure.

“Bringing arterial blood into venous vessels may be considered a unique version of gerrymandering by means of reclassifying the composition of circulation to the foot”, notes Douglas E. Drachman, M.D. in an accompanying editorial.

Source: NEJM

1. DOI: 10.1056/NEJMe2216380
2. DOI: 10.1056/NEJMoa2212754