Reduction of atherothrombotic burden before stent deployment in non-ST elevation acute coronary syndromes: Reduction of myocardial necrosis achieved with nose-dive manual thrombus aspiration (REMNANT) trial. A volumetric intravascular ultrasound study

OBJECTIVES: To test whether thrombus aspiration (TA) reduces the atherosclerotic burden in culprit lesions and "facilitate" percutaneous coronary intervention with stent (S-PCI) among patients with non-ST elevation acute coronary syndromes (NSTE-ACS). BACKGROUND: Evidence on the effects of TA adjunctive to S-PCI in NSTE-ACS is limited and controversial. METHODS: TA was defined "aggressive" when using 7F devices or a catheter/artery ratio >0.6, "conservative" with 6F, and a catheter/artery ratio ≤0.6. Angiography and intravascular ultrasound (IVUS) were performed at baseline, after TA and after stent deployment. RESULTS: TA was accomplished in 61/76 patients (80%) with NSTE-ACS. The aspirated material was red thrombus in 23% and plaque fragments in 49% of cases. Compared with baseline, TA was associated with an 82% increase in minimal lumen diameter and a 15% reduction in diameter stenosis (P < 0.001 for both). After TA, IVUS documented a 24 and 16% increase in minimal lumen area and lumen volume, respectively (P < 0.001 for both), a 7% decrease in area stenosis through an 11% reduction of plaque + media volume (P < 0.001). When compared with "conservative", an "aggressive" TA was associated with a more pronounced reduction in percent area stenosis (P < 0.05) and an increase in percent stent expansion (P < 0.001). The plaque + media volume reduction after TA was correlated with stent expansion (r = 0.261, P = 0.046). CONCLUSIONS: Manual TA reduces atherothrombotic burden in culprit lesions of NSTE-ACS patients before S-PCI and, when deep plaque removal is obtained, TA optimizes subsequent stent expansion.