Looking beyond the gunsight: A potential bailout technique for arterial and venous recanalization

Abstract

The "gunsight approach" was initially described as the use of overlapping snares and through- and-through puncture of the portal vein and inferior vena cava for the creation of a transcaval portosystemic shunt. This technique can be adapted for the creation of an extra-anatomic chan- nel between any 2 locations where snares can be deployed. We explain the technique, discuss finer technical points, and describe 2 cases where refractory vascular occlusions are crossed using this technique. The first case involves an extensively calcified femoral arterial chronic total occlusion where subintimal tracking past the occlusion is achieved, but luminal re-entry is ham- pered by dense calcific plaque refractory to multiple re-entry devices. The second case involves a chronic venous occlusion along the femoral vein with loss of in-line flow due to prior stenting. In both cases, the gunsight technique was successfully used as a bailout option after standard recanalization techniques were unsuccessful.

Figure 1. a-f.

Gunsight technique for arterial recanalization with trans-intimal flap puncture. (a) Pre-intervention angiogram shows chronic total occlusion at the patient’s mid superficial femoral artery (SFA) with collateralization. (b) Overlapping snares deployed with image intensifier positioned orthogonal to the axis connecting the 2 snares. (c) In-plane and (d) oblique image of percutaneous access needle which has been placed through both snares. (e) Deep snare is closed first and internalized. The wire is withdrawn underneath the skin surface, the superficial snare closed, and the proximal end of the wire is internalized. (f) Post-stenting angiogram demonstrates brisk in-line flow with three-vessel runoff.

Figure 2. a-d.

Schematic diagram of gunsight technique for arterial recanalization demonstrating importance of proper sequence of snare closure. (a, b) Deep snare is closed first. This will allow proper internalization of the wire without losing proximal wire control. (c, d) Snare closer to the skin entry site is closed first. The operator will lose access to the proximal tip of the wire and repeat puncture will be necessary. CTO, chronic total occlusion; SFA, superficial femoral artery; EXT, external to patient.

Supplemental Figure 1. a-h.

Gunsight technique for venous recanalization with puncture across stent. (a) Initial snare placed from right internal jugular access is brought to the level of the occlusion. Contrast injection via Glidecath (Terumo) placed from distal access showing separate channel (arrow). (b) Overlapping snares deployed with image intensifier positioned orthogonal to the axis connecting the two snares. In-plane (c) and oblique (d) image of percutaneous access needle which has been placed through both snares. (e, f) Deep snare is closed first and internalized. (g) The remaining snare is closed and the proximal end of the wire internalized. (h) Post-stent venogram demonstrates brisk in-line flow to the inferior vena cava.