ACS by plaque erosion can be stabilised without stenting, with antithrombotic therapy

Presented at the ESC congress 2016 by: Ik-Kyung Jang (Boston, MA, VS)

Background

The majority (60%) of cases of acute coronary syndrome are caused by plaque rupture, while plaque erosion underlies about 25-44% of cases. Both phenomena have a distinct underlying pathology, receptive to antithrombotic therapy. At plaque erosion, a larger lumen CSA is observed, a platelit-rich thrombus is present and vascular integrity is better maintained than at plaque rupture.
Plaque rupture can be distinguished from plaque eriosion with intracoronary optic coherence tomography (OCT). In this proof-of-concept study, this was applied in 405 ACS patients who presented at the emergency room and underwent coronary angiography. This study tested the hypothesis that patients with plaque erosion can be stabilised with effective antithrombotic treatment without stent placement, thereby abrogating both early and late complications related to the stent. Patients received aspirin, ticagrelor and unfractionated heparin (UFH) before catheterization. Glycoprotein IIb/IIIa inhibitor or aspiration thrombectomie were applied at the discretion of the treating cardiologist. UFH and low molecular weight heparin were given 3 additional days. DAPT consisting of aspirin and ticagrelor was continued. Follow-up OCT was performed after 1 month.

Main results

• In 60.7% plaque rupture was seen and erosion occurred in 25.4% (n=103) of patients.
• After 1 month 47 out of 60 patients (78.3%) reached the primary endpoint of over 50% reduction in thrombus volume.
• 22 patients had no residual thrombus after 1 month (100% reduction).
• OCT analysis showed that the median thrombus volume reduced from 3.7 mm at baseline (n=60) to 0.2 mm at follow-up (n=55), meaning a median percentage decrease of -94.2% (IQR: -100.0 to -63.7, P<0.001). (Mean volume: reduction from 10.0 mm to 1.7 mm, mean reduction -79.2, SD: 27.7, P<0.001).
• Median minimal flow area increased from 1.7 mm² at baseline to 2.1 at follow-up, meaning a median percentage increase of 15.0% (IQR: -8.6 tot 40.5 P=0.002). (Mean minimal flow area was 2.3 at baseline and 2.9 at follow-up, mean increase: 27.4, SD: 56.4, P=0.001).
• One patient died as a consequence of a gastrointestinal bleeding on DAPT, and another had no improvement in the stenotic artery after 1 month, due to which was decided to conduct PCI.

Conclusion

This pilot study shows that erosion is the underlying pathology in a quarter of ACS-patients. Antithrombotic therapy without stent implantation was effective at reducing thrombus volume and it increased flow area without recurrent events at 1 month.
Randomised studies are needed to reproduce these findings and to evaluate the long term outcome of this new treatment strategy in patients with ACS as a result of plaque erosion.

“If this conservative approach without a metal stent or a polymer scaffold turns out to be effective and safe, it can become a new treatment paradigm for over a quarter of patients with ACS, thereby abrogating both early and late complications related to the stent”, said Ik-Kyug Jang in a press release. “Currently all patients with ACS are uniformly treated with stenting regardless of underlying pathology. This study, for the first time, demonstrates that patients with ACS caused by erosion may benefit from a tailored therapy with anti-thrombotic medications,” said Jang. “If we can identify ACS patients with erosion without an invasive procedure, those patients may be triaged to a conservative therapy pathway instead of invasive catheterization and stent implantation.” During the press conference Jang added that they are trying to find biomarkers with which they could distinguish erosion from rupture.

Our reporting is based on the information provided during the ESC congress –