Abstract 3012: Impact of Thromboaspiration during Primary PCI on Microvascular Damage and Infarct Size: Acute and Long term ce-MRI Evaluation.

Abstract

Background: In patients with ST-elevatrion myocardial infarction (STEMI), impairment of microcirculatory function is a negative independent predictor of myocardial function recovery. Compared with conventional stenting, thrombectomy during primary percutaneous coronary intervention (PCI) seems to improve the parameters of myocardial tissue perfusion. We sought to evaluate the impact of thromboaspiration on procedural outcomes and microascualr damage and infarct size by contrast enhanced-MRI (ce-MRI) as compared to conventional primary PCI. Methods:We randomized 75 patients (mean age 64.3±10.2, 55 male) referred to our Hospital with a STEMI (<9 hours from symptoms onset) and an occlusive thrombus at basal angiography, to thromboaspiration with a manual device (Export ®-Medtronic (n=38) (group 1)) and standard PCI (n=37) (group 2). 3 days after procedure and 3 months later a ce-MRI was performed to assess the microvascular damage (as hypoenhancement (HO)) and infarct size (as hyperenhancement(HR)) in the 2 groups. The primary end points were the angiographic result in terms of the TIMI ≥ II flow , MBG ≥ 2 and ST-segment resolution (STr)≥ 70% post-stenting and the microvascular damage (grams/g) and infarct size (grams/g) evaluated by ce-MRI. Results: No differences on baseline, clinical and angiographic preprocedural findings were observed between the two groups. After trombectomy, a TIMI II flow was present in in 38.6 vs 19.6% (p=0.054) and TIMI III was 30.7 vs 72.5% (for group 1 and 2, respectively, p<0.001). Postprocedural MBG ≥2 was 70,3% vs 28,7% (p<0.001) and 90′ ST-segment resolution was 80% vs 37.5% (for group 1 and 2, respectively, p<0.001). Ce-MRI showed an HO of 4.04±5.87g at 3 days vs 0.12±0.4g at 3 months (p= 0.04) in group 1, and 3.7±5.04 vs 2.7±2.3 (3 d and 3 m. respectively)(p=ns) in group 2. At 3 days HR was 17.39±15.6g vs 11.01±8.07g at 3 months in group 1 (p=0.04) and 14.02±7.5g vs 13.6±12.7g ( 3 d. and 3 m. respectively) (p=ns) in group 2. Conclusion:Compared with conventional stenting, a pretreatment with thrombectomy during primary PCI, improves epicardial flow and procedural outcomes. The long term ce-MRI evaluation suggests a reduction in microvascular damage and infarct size compared with the acute evaluation in the thrombectomy group.