Medical Therapy Deemed Adequate for Plaque Erosion

Researchers at Massachusetts General Hospital (MGH; Boston, USA) and the 2nd affiliated hospital of Harbin Medical University (China) conducted a study involving 405 patients presenting with ACS and ST-segment elevation myocardial infarction (STEMI) to the emergency room (ER). Plaque erosion was identified in 25.4% of the patients, as diagnosed by optical coherence tomography (OCT) and residual diameter stenosis lower than 70% on a coronary angiogram.

The 60 patients that enrolled in the study were treated with anti-thrombotic therapy without stent implantation; if needed, aspiration thrombectomy was performed. OCT was repeated in 55 patients who completed one-month follow-up, and thrombus volume was again measured. The primary endpoint was higher than 50% reduction of thrombus volume at one month, compared with baseline. The secondary endpoint was a composite of cardiac death, recurrent ischemia requiring revascularization, stroke, and major bleeding.

The results showed that 78.3% of the patients met the primary endpoint, with 40% of them with no visible thrombus at one month. Mean thrombus volume decreased from 3.7 mm3 to 0.2 mm3, and minimal flow area increased from 1.7 mm2 to 2.1 mm2. One patient died of gastrointestinal bleeding, and another patient required repeat percutaneous coronary intervention (PCI). The rest of the patients remained asymptomatic. The study was presented at the annual meeting of the European Society of Cardiology (ESC), held during August 2016 in Rome (Italy).

“Anti-thrombotic therapy without stent implantation effectively reduced thrombus volume and enlarged the flow area without re-occlusion of the culprit lesion at one month, in predominantly young Chinese males with a high prevalence of smoking,” concluded lead author Ik-Kyung Jang, MD, PhD, of MGH, and colleagues. “Randomized trials will be needed to reproduce this pilot data and to further evaluate the long-term outcomes of this new treatment strategy in patients with ACS caused by plaque erosion.”

The underlying mechanisms for ACS with STEMI include plaque rupture, plaque erosion, and calcified nodule, with plaque erosion responsible for 22–44% of cases. Since plaque erosion occurs over lesions rich in smooth muscle cells and proteoglycans, with superficial endothelial denudation, preserved vascular integrity, a larger residual lumen, and a platelet-rich thrombus, the researchers hypothesized that these patients might be stabilized by effective anti-thrombotic therapy without the need for stent implantation and its consequential risks.

Related Links:
Massachusetts General Hospital
Harbin Medical University