Vascular Tissue Reaction to Acute Malapposition in Human Coronary Arteries

Abstract

Background-The vascular tissue reaction to acute incomplete stent apposition (ISA) is not well known. The aim of this study was to characterize the vascular response to acute ISA in vivo and to look for predictors of incomplete healing. Methods and Results-Optical coherence tomography studies of 66 stents of different designs, implanted in 43 patients enrolled in 3 randomized trials, were analyzed sequentially after implantation and at 6 to 13 months. Seventy-eight segments with acute ISA were identified in 36 of the patients and matched with the follow-up study by use of fiduciary landmarks. The morphological pattern of healing in the ISA segments was categorized as homogeneous, layered, crenellated, bridged, partially bridged, or bare, depending on the persistence of ISA and on the coverage. After 6 months, acute ISA volume decreased significantly, and 71.5% of the ISA segments were completely integrated into the vessel wall. Segments with acute ISA had higher risk of delayed coverage than well-apposed segments (relative risk 2.37, 95% confidence interval 2.01-2.78). Acute ISA size (estimated as ISA volume or maximum ISA distance per strut) was an independent predictor of ISA persistence and of delayed healing at follow-up.

Incidences, Predictors, and Clinical Outcomes of Acute and Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

“…6 A recent OCT study reported that acute stent malapposition was observed in 36 of 43 (83.7%) patients who received bare-metal stents or DES. 8 In the present study, the incidence of acute stent malapposition was as high as 62%. The higher incidence of acute stent malapposition in our study may be explained by the ability of OCT to detect small lesions with greater accuracy than IVUS.…”

“…7,8 All OCT images were analyzed at a core laboratory (Cardiovascular Research Center, Seoul, Korea) by analysts who were blinded to patient and procedural information. Crosssectional OCT images were analyzed at 1-mm intervals.…”

“…If malapposed struts were detected by poststent OCT (ie, acute stent malapposition), each cross-section of the poststent OCT image was matched with corresponding cross-sectional images of the follow-up OCT image as accurately as possible based on the distance from fiduciary landmarks (eg, stent edges, side branches, or calcification). 8 The lesions were then appropriately classified as resolved acute stent malapposition lesions with or without late-acquired stent malapposition or late-persistent stent malapposition lesions with or without late-acquired stent malapposition (Figure 1). In addition, the longitudinal locations of malappositions were classified as stent edges (<5 mm from the proximal or distal edge of the stent) or stent body.…”

Predictors and Long‐Term Clinical Impact of Acute Stent Malapposition: An Assessment of Dual Antiplatelet Therapy With Drug‐Eluting Stents (ADAPT‐DES) Intravascular Ultrasound Substudy

“…Studies using optical coherence tomography (OCT) have reported a frequency of ASM that has ranged from 39.1% to 83.7%,19, 20, 21, 22 suggesting that it is ubiquitous after implantation if more sensitive methods are used to assess its frequency. Any finding seen in the majority of stents is of limited value in predicting adverse events.…”

Optical Coherence Tomography for Study of <i>In Vivo</i> Pathobiology and for Optimization of Percutaneous Coronary Intervention

“…[73][74][75][76][77] Incomplete stent apposition (Fig. 3B) may be related to persistent malapposition, 75) or delayed neointimal coverage, 78) but small incomplete stent apposition is not related to clinical events. [73][74][75][76]79) Tissue protrusion (Fig.…”