In-hospital Clinical Outcome of Deferred Stenting Versus Immediate Stenting in the Management of Acute STEMI Presenting With High Thrombus Burden: A Randomized Control Study

Angiographically, intracoronary thrombus is defined as the presence of a filling defect with reduced contrast density or haziness. Angiographic evidence of thrombus can be seen in 91.6% of patients who present with STEMI(1). Large intracoronary thrombus has an incidence of 16.4% of patients with acute coronary syndrome (ACS).

Thrombus encountered in the setting of ACS has been correlated with acute complications during percutaneous coronary interventions including: 3 times higher MACE - ischemic complications, lower procedural success, higher distal embolization leading to slow/no flow, high mortality, ST elevation and longer hospital stays.

High thrombus burden can be defined using Yip's criteria:

1. Large infarct-related artery (visually estimated reference vessel diameter ≥ 4 mm)
2. Angiographic thrombus with the greatest linear dimension > 3 times the reference vessel diameter;
3. "Cutoff pattern" (lesion morphology with an abrupt cutoff without taper before the occlusion);
4. Accumulated thrombus (> 5 mm of linear dimension) proximal to the occlusion;
5. Floating thrombus proximal to the occlusion;
6. Persistent dye stasis distal to the obstruction. IF more than two criteria indicate the presence of very high thrombus burden.

PCI Strategies introduced in HIGH thrombus BURDEN include incorporation of both pharmacological and mechanical thrombus removal.