Dialysis a Key Predictor of Adverse Outcomes After Endovascular Intervention for CLI

Patients undergoing peripheral endovascular therapy for critical limb ischemia (CLI) have a higher risk for death and major limb amputation if they are on dialysis at the time of the procedure, according to a study published online July 24, 2015, in the Journal of Vascular Surgery. 

“These data may facilitate efforts to improve patient selection and, after further validation, enable risk-adjusted outcome reporting for CLI patients undergoing [peripheral intervention],” write Daniel J. Bertges, MD, of the University of Vermont Medical Center (Burlington, VT), and colleagues.

The investigators looked at data from the Vascular Study Group of New England (VSGNE) peripheral vascular intervention registry on 1,244 patients (mean age 70 years; 58% men) who underwent peripheral endovascular treatment for CLI between January 2010 and December 2011.

The primary indication for intervention was tissue loss in 71% and rest pain in 29%. Most patients had comorbidities, including a history of hypertension in 90%, prior or current smoking in 75%, and diabetes in 61%. Types of intervention were angioplasty alone, stenting, stent grafting, and atherectomy.

Approximately half of patients had a single artery treated. Arterial segments undergoing intervention were femoral-popliteal (48%), aortoiliac (27%), and infrapopliteal (25%).

Dialysis the Common Denominator

Technical success was 92%, with failure to cross the lesion and residual stenosis > 30% each occurring in 4% of cases. Complications included access-site hematoma (5.0%) or occlusion (0.3%) and distal embolization (2.3%). At 30 days, rates of mortality and major amputation were 2.8% and 2.0%, respectively. Reintervention, whether open or percutaneous, was needed in 8.0% of patients within 1 year.

On multivariable Cox analysis, 7 factors were identified as independent predictors of increased 1-year mortality (table 1).

The single factor that predicted a lower mortality risk was independent ambulation prior to intervention (adjusted HR 0.7; 95% CI 0.6-0.9).  

Dialysis dependence, not living at home preoperatively, and congestive heart failure also were associated with worse amputation-free survival, along with tissue loss, male sex, and treatment of certain arterial segments.

Additionally, 5 factors independently predicted major amputation at 1 year (table 2).

Conversely, being a current or former smoker was tied to a lower risk of major amputation (adjusted HR 0.6; 95% CI 0.4-1.0).

Poor Outcomes ‘Sobering’

According to the authors, the “relative paucity of quality outcome data” further complicates the decision-making process when it comes to choosing appropriate treatment in CLI patients, making it important to identify predictors of poor outcomes.

While previous studies have shown some of the same predictive factors after lower-extremity bypass, the current study highlights important differences, Dr. Bertges and colleagues say. Furthermore, the only risk factor common to reduced 1-year survival, amputation-free survival, and freedom from amputation was dialysis. This finding, they say, emphasizes the importance of renal function to prognosis.

“In our study the poor outcomes in patients on dialysis was particularly sobering, with mortality rates of 44% at 1 year,” they note.

They add that a matched comparison of patients from peripheral vascular intervention and lower-extremity bypass registries “may further elucidate the survival difference between patients undergoing open and endovascular revascularization.”

Source: 
Vierthaler L, Callas PW, Goodney PP, et al. Determinants of survival and major amputation after peripheral endovascular intervention for critical limb ischemia. J Vasc Surg. 2015;Epub ahead of print. 

Disclosure:

• Dr. Bertges reports no relevant conflicts of interest. 

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