OCT analysis in patients with very late stent thrombosis.

OBJECTIVES: We report optical coherence tomography (OCT) findings in 33 patients who presented with very late stent thrombosis (VLST) after either drug-eluting stent (DES) or bare-metal stent (BMS) implantation.

BACKGROUND: VLST is a potentially life-threatening complication, but the underlying mechanisms remain unclear.

METHODS: In 33 patients (27 DES- and 6 BMS-treated lesions) with definite VLST, OCT images were acquired before either thrombus aspiration or intravascular ultrasonography (IVUS) imaging.

RESULTS: The median duration from implantation was 61.5 months in the DES group and 109.1 months in the BMS group. In the overall cohort, combining DES and BMS, 94% showed intraluminal thrombi. VLST was associated with in-stent neointimal rupture in 23 patients (70%); 22 had thrombi near the site of neointimal rupture. Stent malapposition was observed in 14 (42%) lesions, but only 9 of them showed thrombi at the site of stent malapposition; moreover, 6 (18%) stented segments with malapposition also had neointimal rupture. Only 2 (6%) lesions had no evidence of neointimal rupture or malapposition. Stent fracture was detected in 3 DES-treated lesions, all with concomitant neointimal rupture. Compared with lesions without neointimal rupture, lesions with neointimal rupture showed a higher frequency of ST-segment elevation myocardial infarction (65% vs. 20%, respectively, p = 0.040) as well as a higher peak creatine kinase-myocardial band level (163.1 ng/ml vs. 15.7 ng/ml, respectively, p = 0.017).

CONCLUSIONS: OCT imaging indicated that advanced neoatherosclerosis with neointimal rupture and thrombosis was the most common mechanism of definite VLST and was associated with a high frequency of ST-segment elevation myocardial infarction.