SLR - May 2018 - Ashmi H. Patel

Predictors of Delayed Wound Healing After Successful Isolated Below-The-Knee Endovascular Intervention in Patients with Ischemic Foot Wounds

Reference: Das SK, Yuan YF, Li MQ. Predictors of Delayed Wound Healing After Successful Isolated Below-The-Knee Endovascular Intervention in Patients with Ischemic Foot Wounds. J Vasc Surg. 2018 Apr;67(4):1181–1190.

Scientific Literature Review

Reviewed By: Ashmi H. Patel, DPM

Residency Program: Kaiser Permanente North Bay Consortium, Vallejo, CA

Podiatric Relevance: Diabetic foot wounds can be limb-threatening for patients living with diabetes and peripheral vascular disease (PVD). Therefore, the prevention of ulceration in this patient population can mean preventing major amputations, long-term hospitalizations and life-threatening infections. It can become complicated with PVD, so foot and ankle surgeons often work collaboratively with vascular surgeons to promote limb salvage. In the setting of PVD, revascularization often plays a crucial role in healing wounds. However, wounds may not heal despite successful endovascular revascularization. This study examined predictors of delayed wound healing and their utility in risk stratification for endovascular intervention in patients with severe peripheral vascular disease.  

Methods: A retrospective analysis was performed of prospectively collected single-center data. They included all patients with critical limb ischemia (CLI) and foot wounds who were status-post an isolated below the knee (BTK) percutaneous transluminal angioplasty (PTA) between May 2008 and June 2013. A total of 118 patients with 137 wounds were included in this study. Inclusion criteria included successful BTK PTA and a clinical diagnosis of CLI (per ankle brachial index, transcutaneous oxygen pressure, and stenosis as heard on Doppler). Exclusion criteria included patients with CLI due to BTK lesions combined with above the knee (ATK) lesions and those with unsuccessful PTA. A team of vascular surgeons and interventional radiologists performed the endovascular procedures. Patients were followed up at one month, three months, six months and subsequently every six months until the two-year mark. The primary end point was complete healing after endovascular treatment within 12 months.

Results: Eighty-one patients (92 limbs) out of 118 (137 limbs) healed completely. The cumulative wound healing rates were as follows: 13.9 percent at three months, 43.8 percent at six months, 57.7 percent at nine months and 65.7 percent at 12 months. The findings suggested the following as independent predictors of wound nonhealing: ESRD, albumin level < 3.0 g/dL, CRP >5.0 mg/dL, major tissue loss (wounds located between first MTPJ to the ankle), wound infection, gangrene, wound depth (per UT classification), duration of the wound > 2 months, insulin use and lack of below-the-ankle runoff. Wound healing rates decreased significantly as the number of risk factors increased. Additionally, University of Texas grade 3 wounds were independent predictors of wound nonhealing, although both grade 2 and 3 had poorer wound healing rates compared to grade 1. The cumulative wound healing rates were significantly lower in wounds with a duration ≥2 months (43.4 percent) versus those with duration of < 2 months (86.7 percent). Lastly, wound-healing rates significantly differed between the infected group (46.2 percent) versus noninfected group (86.1 percent).

Conclusions: This study concluded that these predictors of wound nonhealing can be used for risk stratification when considering endovascular treatment in the setting of CLI. However, limitations include that it was a single-center study and was nonrandomized/nonblinded, which could influence bias. Additionally, only balloon angioplasty was used due to availability. This study suggests using wound depth and duration for risk stratification because larger, long-term wounds are more likely to be infected and may result in poor outcomes. 

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