Effectiveness of Thrombus Aspiration in Plaque Reduction for Patients With Acute Coronary Syndromes (REMNANT)

• The change in plaque volume as assessed by intravascular ultrasound (IVUS). [ Time Frame: From baseline to 10 minutes after thromboaspiration (TA) ] [ Designated as safety issue: No ]
  The reduction of plaque volume after TA, assessed as (Baseline P+M)- (Post-TA P+M);
  
  

• Histopathology assessment of aspirated material. [ Time Frame: One week after PCI ] [ Designated as safety issue: No ]
  Quantitative analysis: size and weight. Qualitative evaluation: a) thrombus containing only platelets, b) a thrombus with an erythrocyte component c) any fragment of vessel wall, cholesterol crystals, inflammatory cells or collagen tissue.
  
  
• Myocardial infarct size by markers of myocardial injury/necrosis [ Time Frame: Up to 72 hours after PCI ] [ Designated as safety issue: Yes ]
  Myocardial infarct size will be determined as the area under the curve of serial CK-MB and cardiac Troponin I assessment
  
  
• The change in thrombus burden as assessed by Optical Coherence Tomography (OCT) [ Time Frame: From baseline to 10 minutes after thromboaspiration (TA) ] [ Designated as safety issue: No ]
  Thrombus burden will be assessed with a semiquantitative scale (0-4) by OCT at baseline and after TA
  
  

Periprocedural myocardial infarction (MI) has an independent adverse prognostic relevance. Several trials have documented a reduction in the occurrence of periprocedural MI through various pharmacological strategies, with enhanced inhibition of platelet aggregation or high dose statins. However, real-world registries still document an incidence of periprocedural MI in 30-40% of patients. Currently available intravascular imaging techniques, Intravascular Ultrasound (IVUS) and more recently available Optical Coherence Tomography (OCT) allow a precise evaluation of the coronary plaque and can be extremely useful for monitoring plaque modifications obtained with thrombus aspiration (TA). Plaque burden will be assessed as plaque + media (P+M), commonly measured with IVUS by subtracting lumen (L) to external elastic membrane (EEM) cross sectional area (P+M= EEM-L).

Expecting a mean plaque volume of 160±50 mm3 in a population of patients with ACS undergoing PCI, a sample size of at least 45 patients (52 lesions) with a recent (<15 days, but after 24 hours) STEMI or a non-ST elevation (NSTE)-ACS within 72 hours of symptoms would provide a 90% power to detect a 20% reduction in the plaque volume after TA with an alpha (probability value) of 0.05.