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13-09-2010 | Cardiology | Article

Late stent malapposition risk greater with paclitaxel-eluting than bare metal stent


Free abstract

MedWire News: A sub-analysis of the HORIZONS-AMI study suggests that the risk for late stent malapposition (LSM) after percutaneous coronary intervention (PCI) is higher in coronary artery lesions treated with a paclitaxel-eluting than with bare metal stents (BMS).

However, acute stent malapposition (ASM) occurs with similar frequency when PCI is performed with paclitaxel-eluting stents (PES) or BMS.

Ning Guo (The Cardiovascular Research Foundation, New York, USA) and team explain: "At follow-up, LSM was more common in PES-treated lesions compared with BMS-treated lesions mainly because of a higher incidence of late acquired stent malapposition (LASM).

"LASM was due to positive remodeling and plaque/thrombus resolution."

In an intravascular ultrasound substudy of the randomized HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial, Guo and colleagues enrolled 241 ST-elevation myocardial infarction (STEMI) patients with 263 native coronary lesions who received PCI with PES (201 lesions) or BMS (62 lesions).

Stent malapposition was determined by ultrasound immediately after PCI, and at 13-month follow-up. ASM and LSM were defined as stent malapposition visualized during the initial ultrasound, and malapposition absent at the initial ultrasound but present at 13-month ultrasound, respectively.

Writing in the journal Circulation, Guo et al report that they found no significant difference in the rates of ASM in PES- and BMS-treated lesions, at 34.3% and 40.3%, respectively.

Of note, resolution of ASM at 13-month follow-up occurred at a similar rate of 39.1% in PES-treated lesions and 40.0% in BMS-treated lesions.

However, LSM occurred more frequently in PES-treated lesions than in those treated with BMS, at 46.8% versus 29.0%, respectively (p=0.007). Of these, 44% and 83%, respectively, were ASMs that had persisted, and all others were LASM.

The researchers also found that the presence of plaque/thrombosis protrusion or the use of PES increased the risk for LASM, with odds ratios of 5.60 and 6.32, respectively, (p<0.001 for both).

Guo and team report that at 1-year follow-up, the presence of stent malapposition was not associated with any deaths or occurrences of stent thrombosis.

However they conclude: "Ongoing follow-up to 3 years will determine the relationship of longer-term major adverse cardiac events and ASM and especially LASM in both BMS and PES cohorts."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Lauretta Ihonor

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