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The aim of our study is to characterize, using OCT, the morphologic features of calcific plaques after rotational atherectomy, adjunctive balloon angioplasty and stenting.
Methods and Results
A total of 57 consecutive patients who had undergone angioplasty using rotational atherectomy were included. The 67 lesions treated were classified according to the indication of rotational atherectomy as massive calcification (n=26), calcific nodule (n=23), uncrossable (n=11) or non-dilatable lesions (n=7). An OCT study was done before atherectomy in 14 lesions, after a rotational atherectomy in all 67 lesions, after a balloon dilatation in 6 lesions and post stenting with post dilatation in all lesions. The treated lesions were located in the left anterior descending (n=30), in the right coronary artery (n=28), and the left circumflex artery (n=9). The OCT appearance of the lesions after atherectomy is very specific of the substrate encountered by the burr: sharp cuts with smooth surface in presence of calcifications and irregular boundaries and less delimitated cuts in presence of fibrotic lesions. Peeling of the intima at the beginning of the burr action is constant regardless of the type of lesion. Mean calcium arc was 318 degrees, mean calcium thickness was 1.03mm. Mean diameter of the ablation as measured by OCT was 1.57 mm and mean burr size was 1.54. Mean burr to artery ratio was 0.51. Twenty-three lesions required 2 burrs. Dissections were unusual (13% of lesions) and observed mainly in uncrossable lesions (80%). After stenting, deep medial dissections are frequent especially in heavy calcified lesions and calcific nodules and contribute significantly to lumen enlargement while the area of ablation in the calcified part of the plaque remained unaltered. After systematic post dilatation, incomplete stent apposition was encountered in 6 lesions (9%).
OCT represents a unique opportunity for studying in vivo the mechanism of action of rotational atherectomy in different types of lesions. Insights from this study allowed us to tailor our approach to treat calcific lesions.