In vivo optical coherence tomography of very late drug-eluting stent thrombosis compared with late in-stent restenosis.

BACKGROUND: Autopsy findings have suggested delayed arterial healing as a primary cause of very late stent thrombosis (VLST) after drug-eluting stent (DES) implantation. METHODS AND RESULTS: Optical coherence tomography of DES-treated lesions that developed VLST (n = 6) was compared with that of DES-treated lesions that developed late in-stent restenosis (L-ISR: n = 32) among patients with recurrent ischemia >1 year after DES implantation (mean, 37 ± 17 months), and with the stented segment without any evidence of VLST or L-ISR (no-event: n = 20; mean, 38 ± 19 months). The proportion of uncovered and malapposed struts in each stented segment was evaluated. A total of 961 frames, 9,763 struts were analyzed. The proportion of uncovered struts was higher in the VLST group than in the L-ISR group and the no-event group (29.2 ± 22.8%, 7.9 ± 9.7%, and 7.6 ± 8.0%, respectively; P = 0.0002). The proportion of malapposed struts was higher in the VLST group than in the no-event group (7.3 ± 8.7% vs 1.1 ± 2.4%, P = 0.01). Two patients in the VLST group had lower rates of uncovered and malapposed struts, but this involved lipid-laden-like neointima with disruptions. CONCLUSIONS: Delayed neointimal coverage and incomplete stent apposition were frequently observed in the DES-treated lesions that developed very late thrombosis. Lipid-laden-like neointima with disruption within the DES may be another possible mechanism for very late thrombosis.

The potential benefits and risks of the use of dual antiplatelet therapy beyond 6 months following sirolimus-eluting stent implantation for low-risk patients.

BACKGROUND: The optimal duration of dual antiplatelet therapy (DAT) in patients undergoing intracoronary sirolimus-eluting stent implantation remains controversial. OBJECTIVE: To evaluate the clinical effects of long duration DAT in patients undergoing intracoronary sirolimus-eluting stent implantation in daily practice. In addition, to attempt to identify the optimal duration of DAT after implantation of a sirolimus-eluting stent. METHODS: We retrospectively report on 1293 consecutive patients who underwent successful intracoronary sirolimus-eluting stent implantation. We analyzed the cumulative incidence of stent thrombosis, non-fatal myocardial infarction (MI), death from cardiac causes, and the cumulative incidence of bleeding complications. RESULTS: We compared the study end point in patients who received DAT for <6 months (n=1136) with that for patients who received DAT for >6 months (n=157). The median follow-up period was 1260 ± 462 days. Major bleeding occurred in 35 patients and intracranial hemorrhage in 8. In patients on DAT for >6 months, the incidence of any bleedings, major bleedings, and intracranial hemorrhage was significantly increased. On the other hand, there was no significant difference between the two groups in the risk of the primary end points (stent thrombosis, non-fatal MI, death from cardiac causes, death or MI). CONCLUSIONS: Prolonged DAT for more than 6 months was not significantly more beneficial than aspirin monotherapy in reducing the risk of the occurrence of acute MI, stent thrombosis, and death, although it was associated with an increase in bleeding complications for low-risk patients.

The impact of gender difference on the effects of preinfarction angina on microvascular damage with reperfused myocardial infarction.

BACKGROUND: Few studies have addressed gender differences in evoking preconditioning. In an experimental study, it was reported that the preconditioning effect disappeared after gonadectomy. OBJECTIVES: We sought to determine the effects of preinfarction angina (PA) on myocardial damage using intravenous contrast echocardiography. METHODS: We studied 334 consecutive patients with anterior myocardial infarction (AMI) who underwent successful angioplasty. All patients underwent myocardial contrast echocardiography (MCE) 14 days after percutaneous coronary intervention (PCI). Contrast defect was calculated as contrast defect area/myocardial area. Typical angina occurring in the 24-hour period preceding myocardial infarction was present in 133 patients (29 women) (group PA) and absent in 201 patients (43 women) (group non-PA). All women were postmenopausal. RESULTS: The contrast defect size and peak creatinine phosphokinase (max CPK) level in women were both significantly higher than that of men in group PA (18.3% +/- 6.3% vs 11.9% +/- 9.0%; P < 0.01 and 5000 +/- 599 IU/L vs 2672 +/- 221 IU/L; P < 0.005). The functional status of the myocardium among group PA, as expressed by risk area wall motion score index, was better in men than in women at 14 days (1.1 +/- 0.8 vs 1.7 +/- 0.8; P < 0.01) and at 6 months (0.7 +/- 0.4 vs 1.6 +/- 0.6; P < 0.01). However there were no significant gender differences in group non-PA. Multivariate regression analysis showed that the female gender (P < 0.05) was a significant independent predictor for microvascular damage. CONCLUSIONS: These findings suggest that preconditioning effects were attenuated in women with reperfused AMI.