The impact of isolated tibial disease on outcomes in the critical limb ischemic population

Abstract

Background: Most patients with critical limb ischemia (CLI) have multilevel infrainguinal peripheral arterial disease (M-PAD). One-third of CLI patients will have isolated tibial disease (ITD). The treatments for multilevel disease or ITD differ depending on whether open or endovascular procedures are used, but we questioned whether outcomes from these procedures differ. We evaluated outcomes of CLI patients after open and/or endovascular revascularization for CLI and assessed the impact of disease distribution.

Methods: Four hundred forty-six CLI patients (Rutherford 4-6) who underwent revascularization from 2001 to 2005 were evaluated arteriographically and followed after revascularization with noninvasive testing. Based on arteriographic data, all patients with ITD (occlusions in one or more tibial arteries) were compared with patients with occlusive femoropopliteal disease with or without concomitant tibial occlusions (M-PAD). Patients with disease solely above the inguinal ligament were excluded. Clinical data (survival, amputation-free survival, primary patency, secondary patency, limb salvage, maintenance of ambulation, and maintenance of living status) were acquired from a prospective vascular database, allowing the comparison of revascularization outcomes according to disease distribution.

Results: In this study, 36% of patients had ITD and 64% presented with M-PAD. The severity of ischemia at presentation was rest pain (28.5%), ulceration (42.3%), and gangrene (29.1%). In this study, 92% presented exclusively with infrainguinal disease, and 8% presented with both suprainguinal and infrainguinal disease. Risk factors included diabetes mellitus (61.2%), smoking (61.0%), coronary artery disease (57.9%), hypertension (84.3%), hyperlipidemia (40.4%), obesity (15.5%), and chronic obstructive pulmonary disease (19.3%). In comparing the ITD and M-PAD groups, there was no difference in primary patency at 2 years. All other outcomes were statistically different out to 3 years including survival (50.4% vs. 62.6%; p=0.0026, hazard ratio [HR] 0.669); amputation-free survival (35.1% vs. 50.2%; p=0.0062; HR 0.595); limb salvage (65.2% vs. 74.4%; p=0.0062; HR 0.595); maintenance of ambulation (68.9% vs. 76.9%; p=0.0352; HR 0.644); maintenance of living status (79.0% vs. 84.8%; p=0.0403; HR 0.599); and secondary patency (66.8% vs. 74.8%; p=0.0309; HR 0.665). Multivariate analyses reveal that ITD is not an independent predictor of outcome after controlling for confounding factors, of which tissue loss and end-stage renal disease correlate most consistently with poor clinical outcomes.

Conclusion: After revascularization for CLI, ITD carries a worse prognosis (amputation-free survival, limb salvage, survival, maintenance of ambulation, and independent living status) compared with patients with M-PAD, despite the "greater" disease burden in M-PAD patients. ITD patients are more likely to have confounding factors such as diabetes mellitus, renal disease, and worse ischemia at presentation than those with M-PAD. The recognition of ITD may be helpful in identifying high-risk patients but is not an independent risk factor for poor outcomes.