HISTOPATHOLOGICAL CORRELATES OF EARLY ARTERIAL RECOIL FOLLOWING DIRECTIONAL CORONARY ATHERECTOMY

Elastic recoil has been implicated in the pathophysiology of restenosi s after conventional balloon angioplasty alone. Directional atherectom y may attenuate arterial recoil by removing the internal elastic lamin a and medial smooth muscle cells and altering the vessel wall architec ture. This study sought to evaluate early recoil after directional ath erectomy and its relation with excision of deep arterial wall structur es, We prospectively evaluated the correlation of the histopathologic evidence of media or adventitia as assessed in the atheroma retrieved during the procedure with the early changes in minimal lumen diameter after directional atherectomy followed by adjunct balloon dilatation i n 50 consecutive cases. Recoil was assessed by routinely performed 1- and 15-min postprocedure angiograms, and patients were divided into tw o groups according to the absence (group I, n = 26) or presence (group II: n = 24) of recoil. The mean changes in minimal luminal diameter b etween 1 and 15 min was +0.22 mm in group I and -0.14 mm in group II. The absence of recoil was strongly associated with evidence of media t issue in the pathologic analysis as compared with cases with recoil (4 2 vs. 18%: respectively; p = 0.02). Similarly, retrieval of adventitia was seen exclusively in the group without recoil (15 vs. 0% p = 0.06) . Vessels that underwent recoil had significantly larger reference and immediate postprocedure minimal luminal diameters (3.62 +/- 0.57 and 3.02 +/- 0.45 mm, respectively) as compared with arteries with no reco il (3.28 +/- 0.35 and 2.75 +/- 0.43 mm, respectively p < 0.05 for both ). Therefore, early luminal changes, likely related to elastic recoil: correlated with excision of deep wall structures during directional a therectomy. Arteries that showed recoil were larger, possibly due to t hicker muscular layer and/or larger plaque burden as compared with art eries that did not recoil. Thus, optimal tissue debulking during direc tional atherectomy appears to attenuate recoil, providing an additiona l insight into the mechanism of action of this percutaneous revascular ization device.