Evaluation of the REDUCtion of thrombus burdEn with Core Lab OcT assessmenT (REDUCE-CLOTT) study.

Background: Optical coherence tomography (OCT) allows for quantitative analysis of thrombus in coronary vessels. High post-percutaneous coronary intervention (PCI) thrombotic burden as identified by OCT, correlates with adverse angiographic and periprocedural clinical outcomes.

Objective: To assess by OCT the amount of residual thrombus post-PCI without the use of cangrelor, representing the standard of care and the control group of the REDUCE-CLOTT (The REDUCtion of thrombus burdEn with cangreLor by OcT assessmenT) study.

Methods: This was a single-arm observational study of patients who presented with acute coronary syndrome or stable angina with evidence of acute thrombus on baseline OCT evaluation of the target lesion. All patients received treatment with PCI plus standard of care medications, with repeat OCT assessment peri-procedurally after PCI. The primary endpoint was the assessment of residual thrombus on post-PCI OCT, quantified as the total thrombus area (TTA) - calculated by measuring the total prolapsed thrombus area (TPTA), defined as the difference between the outer and lumen contours, and adding any free-floating thrombus.

Results: A total of 17 patients and 18 lesions were included. Most were male (70.9 %), hypertensive (58.8 %), and smokers (64.7 %). Unfractionated heparin was used in 94.1 % and bivalirudin in 5.8 % of cases. TTA was numerically reduced by 35.4 % (relative difference), from 0.48 mm² to 0.31 mm² (p = 0.17). TPTA numerically reduced by 37.5 % (relative difference), from 0.48 mm² to 0.31 mm² (p = 0.15).

Conclusions: PCI plus standard-of-care medications was associated with numerically lower, but not statistically significant, acute reduction of thrombus burden as assessed by OCT post-PCI.