2007 Abstracts: Midterm Outcome Predictors for Lower Extremity Atherectomy Procedures

Introduction: The performance of atherectomy devices has been variable. We evaluated our experience using the SilverHawk™ atherectomy device for lower extremity procedures to determine predictors of midterm success.
Methods: Records of all patients who underwent lower extremity atherectomy with the SilverHawk™ atherectomy catheter were reviewed. Patient demographics, vessel treated, number of vessels treated, lesion characteristics, and post operative course were analyzed. Cumulative patency rates, limb salvage, mortality and factors associated with outcomes were determined using the Kaplan-Meier Method with Cox Proportional Hazards modeling.
Results: Between 1/2004 and 1/2006, 167 vessels were atherectomized with the SilverHawk™ in 73 patients. There were 42 men and 31 women treated, and the mean age was 68.8 +13.8. Five patients had both legs treated for a total of 78 legs treated. Of the 78 legs intervened on, 25.6% (20/78) had 1 vessel treated, 51.3% (40/78) had 2 vessels treated, 11.5% (9/78) had 3 vessels treated, 9% (7/78) had 4 vessels treated, and 2.6% (2/78) had 5 vessels treated. 78% (61/78) of patients had intermittent claudication, 71% (56/78) had rest pain, and 58% (45/78) tissue loss. Adjunctive procedures were performed in 63 vessels in 33 patients (61 pta and 2 pta+stent). 84 vessels treated were totally occluded and 83 stenotic.
Cumulative one year primary, primary assisted, and secondary patency, limb salvage, and survival rates with confidence intervals respectively are: 43% (30,57), 49% (36,63), 57% (43,71), 75%(57,92 ), and 90% (80,100). Multivariable analysis demonstrated tobacco use, renal disease, diabetes, and tissue loss all are predictors of patency loss, while only diabetes and tissue loss were associated with greater limb loss (TABLE 1). There was no difference in patency rates irrespective of location of vessel treated (femoral vs tibial), or degree of stenosis (occluded vs. stenotic). Also, multiple vessels treated in the same patients had no affect on patency. The mean ABI preop was 0.57 + 0.19, and this increased to 0.81+0.21 (P < 0.001) at 30 days post op. Procedure related complications included one peroneal artery rupture, one femoral artery pseudoaneurysm, one access site hematoma.
Conclusions: Lower extremity atherectomy procedures with the SilverHawk™ device are safe and effective means in improving symptoms. However, there is decreased durability in and significant patency and limb loss over time. Diabetes, renal disease, tobacco use, and tissue loss are all associated with inferior outcomes.

Hazard Ratios for Significant Risk Factors