EVALUATION OF DIRECTIONAL ATHERECTOMY STUDIED BY INTRAVASCULAR ULTRASOUND IN FEMOROPOPLITEAL ARTERY-STENOSIS

Purpose: To evaluate the role of intravascular ultrasound (IVUS) befor e and after directional atherectomy (DA) in the treatment of femoropop liteal artery stenosis. Methods: In 12 patients with 16 stenoses IVUS was performed before and immediately after an angiographically success ful DA. This was defined-as a diameter reduction (DR) less than or equ al to 50%, which was calculated using the minimal lumen diameter compa red with the diameter of a nearby ''normal'' segment. In the presence of residual plaque on IVUS an additional DA was performed. Endpoints s tudied were DR less than or equal to 30% on IVUS compared with the IVU S findings of the angiographically normal reference segment, or when n o additional atherosclerotic material could be removed by further DA p assages. Results: Additional DA (mean 1.6 per lesion) had to be perfor med in all patients. Initial DA increased the cross-sectional free lum en area (FLA) from 3.8 +/- 2.0 mm(2) to 8.1 +/- 2.7 mm(2) (p = 0.0004) . Additional DA increased FLA to 9.3 +/- 2.3 mm(2) (p = 0.002) after t he second passage and to 9.8 +/- 2.4 mm(2) (p = 0.09) after the final DA run. The plaque area (PLA) before DA decreased from 18.1 +/- 4.2 mm (2) to 15.4 +/- 4.8 mm(2) (p = 0.002) after the first passage, and to 13.5 +/- 5.0 mm(2) (p = 0.004) and 12.8 +/- 4.4 mm(2) (p = 0.07) after the second and final DA runs, respectively. PLA of the reference segm ent (9.5 +/- 5.7 mm(2)) was significantly smaller (p = 0.006) than the final PLA of the treated lesion, indicating a large amount of retaine d plaque. As a result of DA there was an increase in the area bordered by the medial layer, i.e., the total vessel area (from 21.9 +/- 4.7 m m(2) to 23.0 +/- 4.7 mm(2)), significantly in eccentric and soft lesio ns. On IVUS, dissection and plaque rupture after the final passage was seen in 12 of 16 stenoses; two dissections were seen on the completio n angiogram. After the final passage in all stenoses except three, the DR with IVUS was less than or equal to 30%. Conclusion: Lumen enlarge ment following DA is predominantly due to plaque excision. Vessel expa nsion combined with plaque excision varies in different stenoses and i s an important factor in eccentric and soft lesions. Despite additiona l DA considerable plaque remains.