Histopathologic Evaluation of In-Stent Restenosis at Autopsy in Patients with Coronary Stents
Thomas Huebner, Nathaniel Cresswell, Erik Mont, Fabio Tavora, Allen Burke. University of Maryland, Baltimore; Georgetown, Washington, DC; Messejana Heart and Lung Hospital, Ceara, Brazil; Nova Scotia Medical Examiner Service, Nova Scotia, Canada
Background: Pathologic evaluation of stented coronary arteries at autopsy is labor-intensive. There is no standardized technique for evaluation of stented coronary arteries, and plastic processing requires specialized techniqes. The objectives of this study were to assess the impact of in-stent findings on the final cause of death using paraffin based histologic methods.
Design: We retrospectively studied histologic findings of 87 intracoronary stents from 45 autopsy hearts (35 medical examiner and 10 hospital cases). There were 37 men (59 ± 13 years) and 8 women (64 ± 13 years). Stented arteries were radiographed and decalcified. Stents were removed using microdissection with tungsten carbide scissors or electrolysis. Sections were embedded and processed in paraffin. Restenosis was defined as >75% vessel narrowing as determined morphometrically. Thrombosis and fibrin deposition were documented in each case.
Results: There were 23 Taxus, 21 Endeavor, 10 Cypher, 9 RX Achieve, 6 Xience, 5 MultiLink Vision, 4 MuitiLink Rx, 3 NIR, 3 Palmaz Schatz, 2 AVE GFX, and 1 undetermined stent type. 85 were in native arteries, and 2 in vein grafts. 54 stents were successfully dissolved, 2 were microdissected after unsuccessful electrolysis, and 31 were microdissected. Of 5 patients with recent stent placement, causes of death were acute thrombosis of non-stented artery (2), in-stent thrombosis (1), complications of myocardial infarction (MI, 1) and iatrogenic right ventricular puncture (1). Of the 40 patients with only chronic stents, causes of death were noncoronary (24; 16 unnatural), and coronary (21; 13 sudden cardiac death). Of 32 stents in the coronary death group (CDG) after chronic stent placent, 8 had in-stent restenosis (25%) vs. 5 of 45 in the non-coronary death group (NCDG) (11%, p=0.1); mean percent stenosis was 45% vs. 35%, respectively (p=0.1). Two thrombi were found, one organizing in a vein graft in the NCDG, and one organized occlusive thrombus in the CDG. There were 2 fibrous total occlusions in the CDG and 1 in the NCDG. The rate of arrhythmogenic substrates (healed MI, cardiomegaly) was similar in the CDG and NCDG.
Conclusions: In this study, 1 of 5 deaths in the acute group was related to the stent, and no acute late-stent thromboses were found. There is a mild non-significant increase in restenosis and neointima in coronary deaths vs. non-coronary deaths. The cause of death is rarely impacted by in-stent findings at autopsy.
Monday, March 19, 2012 8:15 AM
Platform Session: Section H, Monday Morning