Dear Readers:

     Critical limb ischemia (CLI), the most severe stage of peripheral arterial disease, affects 250,000 new patients annually in the United States with an estimated 40% requiring amputation within 12 months of a CLI episode, in addition to an annual mortality rate of more than 20%.^1,2 Distal bypass surgery prompts healing of lower extremity ulcers associated with CLI if resulting arterial patency supports skin perfusion pressure of at least 35 mmHg.³ Surgical bypass of the occluded arterial segment improves^3,4 and extends primary arterial patency, though there is insufficient evidence to support improved amputation rates or mortality compared to most other modalities.⁴ What options are available to the individual for whom bypass surgery is no longer feasible? This month’s Evidence Corner reviews two studies evaluating efficacy of modalities for treating CLI in patients without further vascular surgery options, as the search for an effective treatment of CLI continues.

Critical Limb Ischemia

     Reference: Kavros SJ, Delis KT, Turner NS, et al. Improving limb salvage in critical ischemia with intermittent pneumatic compression: a controlled study with 18-month follow-up. J Vasc Surg. 2008;47(3):543–549.

     Rationale: Intermittent pneumatic compression (IPC) is a noninvasive method of increasing arterial circulation and ameliorating intermittent claudication in patients with peripheral arterial disease (PAD).

Objective: Evaluate clinical efficacy of IPC in patients with chronic CLI, nonhealing foot ulcers, and minor toe or transmetatarsal amputation after further      options for arterial revascularization had been exhausted.

     Methods: This retrospective cohort study compared two similar groups, each consisting of 24 consecutive patients, for whom further surgical bypass was not an option, and were cared for in a multidisciplinary community clinic from 1998–2004. Resting ankle-to-brachial ratios of systolic blood pressure (ABI), sitting transcutaneous oximetry (TcPO₂) duplex graft surveillance, and foot radiography confirmed vascular status. Both groups received weekly debridement and biologic dressings for tissue loss and nonhealing amputation wounds of the foot due to CLI. Intermittent pneumatic compression allocation was based solely on a patient’s willingness to use it. The IPC inflation pressure was 85 mmHg to 95 mmHg and was applied for 2 seconds with a 0.2-second rise, 3 cycles per minute, for three 2-hour daily sessions. Adherence was monitored closely. Healing outcomes were “favorable” if complete healing with limb salvage occurred during 18 months. Outcomes were considered “adverse” if nonhealing caused below-knee amputation during that time.

     Results: Groups were comparable at baseline on all arterial and wound parameters; prior amputation and comorbid factors were assessed. Four patients (17%) in the control group and 14 IPC (58%) patients healed (P < 0.01). The likelihood of limb loss in the control group was 7 times that of IPC subjects who also increased in TcPO₂ (P = 0.0038).