Purpose: To assess the diagnostic value of angiography as a guideline for selective stent placement after percutaneous transluminal angioplasty (PTA) of the iliac artery.
Materials and methods: Seventy-nine patients (100 iliac artery lesions) with intermittent claudication were treated with PTA and stent placement if they had a residual intraarterial mean pressure gradient of more than 10 mm Hg across the PTA site. Pre- and post-PTA angiograms were used to determine if stent placement was necessary for improvement of the initial result of PTA. Interobserver agreement was determined by using kappa statistics. Pearson correlation coefficients for the percentage of residual stenosis and the pressure gradient after angioplasty were calculated. Sensitivity and specificity of angiography with regard to secondary stent placement were calculated.
Results: Observer agreement on stenosis grade before angioplasty was good (mean kappa, 0.65). Agreement on angioplasty results was fair (mean kappa, 0.45). Agreement on selective stent placement on the basis of angiographic criteria was poor to fair (kappa = 0.21-0.62). Correlation between percentage stenosis and pressure gradient was low (Pearson coefficient, 0.01-0.17). The sensitivity and specificity of angiography were 45% and 63%, respectively.
Conclusion: Angiography is inadequate for determination of a suboptimal angioplasty result. The decision to perform selective stent placement should be made on the basis of hemodynamic measurements.