Rock-Hard Chronic Thrombotic Occlusion and Its Management in Endovascular Interventions

Abstract

Endovascular recanalization for patient with peripheral arterial disease and the end of its spectrum critical limb ischemia (CLI) has become a preferred method of revascularization due to advancement of techniques and equipment, allowing reduction of limb amputations while maintaining a minimally invasive approach compared to surgical approaches. Interventionalists have undertaken a progressively increasing complexity of diseased vessels in the hopes of providing inline unobstructed flow through occlusions for patients with claudication as well as direct flow to a nonhealing wound in patients with CLI. One of the major roadblocks encountered in lower extremity recanalization procedures is managing severely calcified chronic thrombotic occlusions which decrease luminal revascularization, ultimately increasing use of adjunctive interventions such as subintimal tracking, reentry device utilization, and stent placement. Understanding the histopathology and classification of lower extremity calcifications, imaging findings, and escalation of equipment use provides a thorough background in dealing with these specific cases.

Keywords: critical limb ischemia; interventional radiology; peripheral arterial disease; revascularization.

Fig. 1

Table describing proposed calcification scoring system. (From Rocha-Singh et al. 5 )

Fig. 2

Ultrasound gray scale and color Doppler ( a–c ) images show distal calcified chronic thrombotic occlusion cap. Correlating digital subtraction angiography image confirming ultrasound image findings. (From Mustapha et al. 16 )

Fig. 3

Coronal reformatted images from CT angiography in a diabetic patient with chronic renal failure shows diffuse heavy calcified burden.

Fig. 4

( a–d ) Images demonstrate ultra-short echo sequences being performed on MRI to identify different chronic thrombotic occlusions (CTO), plaque differentiation. Such images can help predict the amount of heavy calcifications in a CTO. (From Roy et al. 7 )

Fig. 5

( a ) Image on left showing arterial layers and chronic total occlusion (orange) with antegrade guidewire entering the subintimal space. Image on right showing guidewire reentering the true lumen, (b) outback reentry catheter positioned in the antegrade access subintimal space of the posterior tibial artery, with a microsnare in the subintimal space of the same artery from the retrograde direction; once snared, the wire is “flossed” and then intervention performed.

Fig. 6

Initial infrapopliteal images show ( a ) extensive calcified vessels with ( b ) abrupt chronic total occlusion of the distal popliteal artery. ( c ) Distal reconstitution of the posterior tibial artery is present. The anterior tibial or peroneal arteries are occluded.

Fig. 7

( a ) Distal posterior tibial artery, common plantar, and branches are patent. ( b ) Antegrade attempts at recanalization encountered significant crossing difficulty due to severely calcified occlusion and subsequently was subintimal. ( c ) Retrograde access in the midposterior tibial artery was obtained.

Fig. 8

( a ) After failed attempts to regain luminal wire entry from the retrograde wire, ultimately noted in the subintimal plane, a microsnare was advanced from the pedal access. ( b ) After successful snaring and flossing of the wire, there was difficulty in passing support catheters and balloons across the chronic thrombotic occlusion to facilitate wire exchange. Therefore, orbital atherectomy was performed over the flossed wire. ( c ) Balloon angioplasty using scoring balloon.

Fig. 9

( a–c ) Postangioplasty, due to recalcitrant stenosis, coronary drug-eluting, balloon-expandable stents were placed along the chronic thrombotic occlusion. Completion images show inline flow through the posterior tibial artery and plantar arch.