Combined Approach to Limb Salvage With Cryoplasty Therapy and Transmetatarsal Amputation in a Patient With Chronic Critical Limb

The patient is a 72-year-old woman who was transferred from a local area hospital for continued work up of PVD with ischemia of the third digit on the left foot. The patient had undergone attempted left lower extremity bypass. However, autogenous veins were found unsuitable to serve as conduit and the procedure was aborted. She was admitted to Yale-New Haven Hospital under the podiatric surgical service for a final attempt at limb salvage. The patient has a significant past medical history: PVD, diabetes, coronary artery disease, hypertension, hypercholesterolemia, myocardial infarction, chronic renal insufficiency, peripheral neuropathy and gangrene of the left third toe. She underwent coronary artery bypass and cholecystectomy on 9/7/04. An attempted lower extremity bypass graft was unsuccessful on 9/24/04. Her medications included oxycodone hydrochloride 40 mg bid, atorvastatin calcium 10 mg daily, metoprolol 50 mg bid, amlodipine 5 mg daily, lisinopril 20 mg daily, stool softener 100 mg daily, aspirin 81 mg daily, multivitamin daily and silver sulvadiazine cream. The patient is allergic to ibuprofen. In general, the patient was in no apparent distress, and was alert and oriented. She had a regular rate and rhythm with positive SI, S2 heart sounds. Lungs were clear to auscultation bilaterally with no rhonchi, rales, or wheezing. Her abdomen was soft, nontender and nondistended with positive bowel sounds. Lower extremity examination revealed left dry necrotic third digit, with no discharge and no erythema, with silver sulvadizaine cream on the dorsal and plantar aspects of the foot. Dorsalis pedis and posterior tibial pulses were nonpalpable, with weak monophasic Doppler signals. Multiple ischemic lesions on the dorsal and plantar aspect of the forefoot were secondary to recent skin biopsies. Skin staples to the dorsum of the ankle and lower leg from the recent lower extremity bypass attempt were noted. Angiogram revealed extensive tibial peroneal disease on the left with occlusion of all vessels to the mid-calf level. There was reconstitution in the anterior tibial that provides dominant flow to the foot and reconstitution of the Dorsalis pedis artery. MRI of the left foot revealed multiple areas of small abscesses associated with the ischemic ulcers, with no evidence of osteomyelitis.

After the failed bypass, the patient was admitted to Yale-New Haven Hospital podiatric service with no pulses and ischemic change to the left foot. Peripheral Vascular Surgery was consulted and repeat vein mapping confirmed the absence of a usable vein conduit. With the history of aborted left lower extremity bypass, plans for endovascular limb salvage were undertaken with Interventional Radiology. Noninvasive vascular testing included TCPO2 of the left pretibial region (49 mm Hg) and the left dorsum (30 mm Hg). A diagnostic angiogram performed prior to the aborted surgical procedure revealed patent abdominal aorta, iliac arteries and left superficial femoral artery. The femoral bifurcation was intact. The above- and below-the-knee popliteal artery also was patent and without stenosis. The posterior tibial artery was occluded at the level of the mid-calf. The peroneal artery was severely diseased. The anterior tibial artery had proximal, hemodynamically significant stenosis and a 30 mm long occluded segment at the level of the lower one-third of the calf. There was hemodynamically significant stenosis of the Dorsalis pedis artery at and just below the level of the ankle joint. An antegrade puncture of the left common femoral artery was performed and a 6-Fr sidearm sheath placed with its tip in the proximal superficial femoral artery. Repeat diagnostic study confirmed the previous findings. A 4-Fr Berenstein catheter with glide coating (Boston Scientific, Natick, Mass.) loaded with a .014” guidewire (Sparta/Core 14, Guidant Corp.) were used to catheterize the anterior tibial artery and cross the stenosis. CryoPlasty therapy was performed with a 3.0 mm x 20 mm PolarCath Peripheral System balloon (CryoVascular Systems, Inc.). Post procedure control angiogram showed excellent result with a less-than-10% residual stenosis and no angiographic evidence of dissection. Attention then was turned towards the occluded segment of the anterior tibial artery. The 4-Fr glide Berenstein catheter was advanced across the treated segment described above and the tip of the catheter placed just above the occluded portion of the artery. Contrast was injected and reconstitution of the post-obstructed anterior tibial artery was documented. The obstructed segment was crossed with a .035” straight, stiff Glidewire (Boston Scientific). The catheter was advanced across the obstruction and its intraluminal position was confirmed with a contrast injection. The obstructed segment was treated with CryoPlasty therapy using the 3.0 mm balloon. A control angiogram following the procedure disclosed minimal residual stenosis and no vessel wall dissection. There was no evidence of distal embolization of plaque fragments. The .014” guidewire was advanced through the balloon catheter and the stenosis of the Dorsalis pedis artery was crossed again utilizing roadmap technique. The stenosis of the Dorsalis pedis artery at and below the ankle was treated with a 2.5 mm x 20 mm CryoPlasty balloon.

A control angiogram following the procedure showed significant improvement in the diameter of the Dorsalis pedis artery with a focal area of spasm at its mid portion. The patient tolerated the procedure well and afterwards was noted to have a strong, palpable Dorsalis pedis pulse. The patient underwent a transmetatarsal amputation on the left foot on 10/6/04, allowing ambulation without a prosthesis. Significant bleeding post operatively was observed, as well as bounding pulses. The patient tolerated the procedure and anesthesia well and was discharged to an intermediate care facility for physical therapy and wound care. The wound has been healing well.

Discussion

Chronic critical limb ischemia has been defined as a nonhealing ulceration or gangrene of the foot or toes and/or rest pain that requires regular use of analgesics.¹ These patients will require some type of intervention to resolve their condition. The objective of revascularization is to augment blood flow to allow for wound healing and avoid major amputation resulting in the need for a prosthesis. Amputation of one or more digits or even transmetatarsal amputation preserves enough of the foot to allow for ambulation. However, after excision of the gangrenous segment, the surgical wound will not heal if there is inadequate blood flow to the area. Diabetics and others with limb-threatening ischemia often have few choices. Bypass surgery may not be possible due to poor quality of vein or previous harvesting of saphenous veins for coronary artery bypass. Angioplasty for infrapopliteal vascular occlusive disease is not new. Dotter and Judkins described three patients with peroneal-tibial trunk angioplasty in their initial report in 1964.² At first coronary balloons were utilized and then specialized angioplasty balloons designed for tibial vessels became available.³ Limb salvage rates were similar to surgery. However, only 20–30% of patients with isolated tibial disease were candidates for endovascular therapy due to the number and length of lesions. Recently, subintimal angioplasty has been described by Bolia, Brennan and Bell.⁴ Others have supported the role of this technique for limb salvage and have successfully treated longer lesions with near 90% technical success.^1,5 The development of CryoPlasty therapy has advanced the mechanical properties of the angioplasty balloon to potentially transform it into an instrument that alters the physiology of the plaque and smooth muscle cells. Liquid nitrous oxide is used to inflated the balloon for 20 seconds at 8 ATM which cools it to -10? C. This freezing action is felt to alter the plaque response to angioplasty, causing it to fracture more uniformly, thus lessening the incidence of flow-limiting dissections. There is a reduction in vessel wall recoil. Finally, the freezing action has been shown in vitro to activate markers of apoptosis. TUNEL assay and Annexin V assay revealed an apoptotic peak at -10? C and no apoptosis above 15?C. In theory, this suspends the ability of smooth muscle cells to secrete matrix, the basis of the restenotic lesion. This case demonstrates the suitability of the small vessel cryoballoon to be delivered to a distal lesion below the ankle. Angioplasty was performed without the creation of a prominent dissection across a 30 mm length occluded segment and two additional sites. There was vigorous bleeding noted during surgery, a favorable prognostic sign, and the surgical wound is healing at three weeks. While the primary objective is limb salvage and wound healing, further follow up in a controlled environment will be necessary before statements regarding patency rates can be made.

The author can be contacted at: john.aruny@yale.edu Dr. Aruny has received honoraria from CryoVascular Systems, Inc. and Boston Scientific Corp., distributor of PolarCath.