Objective: To evaluate the predictive value of serum beta 2-microglobulin level for recurrent stenosis or occlusion in patient undergoing percutaneous transluminal angioplasty (PTA) for lower limb ischemia.
Methods: Between March 2009 and October 2010, 81 patients were admitted with a diagnosis of lower limb ischemia. Among them, 54 patients had a mean age of 64 ± 12 years. The baseline characteristics, stenting and post-procedure events were collected. And the serum level of beta 2-microglobulin was measured by dynamic timing nephelometry assay. Recurrent stenosis or occlusions were confirmed with color Doppler ultrasonography or CTA imaging. Cox regression univariate analysis was performed with variables with P value < 0.20 to investigate the independent predictors of recurrent stenosis or occlusions. Receiver-operating characteristics curves (ROC) were constructed to evaluate the sensitivity and specificity of this model.
Results: The baseline characteristics were evenly distributed in two groups. Twenty-three patients (42.5%) were found to have recurrent stenosis or occlusions. The cumulative primary patency was 85%, 69% and 34%at Month 6, 12 and 24 respectively. The serum levels of beta 2-microglobulin decreased during a follow-up period of 3 months and then increased gradually in patients with recurrent stenosis or occlusion. Cox regression analysis identified the serum level of beta 2-microglobulin as an independent predictor of recurrent stenosis or occlusion (Odds Ratio = 1.459, 95%CI 1.199 - 1.777, P = 0.000). The area under the curve (AUC) of the serum level of beta 2-microglobulin was 0.952 for recurrent stenosis or occlusion. And the sensitivity was 95.7% and the specificity 77.4% on a cut-off value 3.2 mg/L.
Conclusion: With a cut-off value 3.2 mg/L, the serum level of beta 2-microglobulin may be useful for the prediction of recurrent stenosis or occlusion in patients after lower limb PTA.