Key result
High mechanical index ultrasound impulses with microbubbles improve pre-PCI angiographic recanalization ~6-fold vs low index imaging.
Why the study?
Pre-clinical trials showed high mechanical index impulses during microbubble infusion might restore flow in STEMI, motivating testing of its safety and efficacy in humans.
Does diagnostic ultrasound intermittent high mechanical index impulses combined with intravenous microbubbles improve epicardial recanalization and microvascular flow in patients with first STEMI undergoing emergent PCI?
RCT (n=100)
Does diagnostic ultrasound intermittent high mechanical index impulses combined with intravenous microbubbles improve epicardial recanalization and microvascular flow in patients with first STEMI undergoing emergent PCI?
Absolute Event Rate: 60% vs 10%
p-value: p=0.002
High mechanical index ultrasound impulses combined with microbubble infusion prior to and after PCI significantly improves angiographic recanalization and microvascular flow in patients with acute STEMI.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“This is a proof-of-concept study. We were trying to prove that this works in humans. Now we are about to start a multicenter study in Brazil and probably in 2 years' time we are going to be using this at point of care in ambulances.”
“I think this is very exciting, but it's also very preliminary, of course. So many times we've seen small trials come up with unreliable findings, so we look forward to the further development of this to see if it might be replicated.”
“We have been waiting a long time to find a safe treatment that would reduce microvascular obstruction which can occur even with a successful stent procedure.”
Supports adjunctive HMI microbubbles before PCI to boost recanalization in STEMI; extends sonothrombolysis evidence to epicardial patency.
BACKGROUND: Pre-clinical trials have demonstrated that, during intravenous microbubble infusion, high mechanical index (HMI) impulses from a diagnostic ultrasound (DUS) transducer might restore epicardial and microvascular flow in acute ST-segment elevation myocardial infarction (STEMI). OBJECTIVES: The purpose of this study was to test the safety and efficacy of this adjunctive approach in humans. METHODS: From May 2014 through September 2015, patients arriving with their first STEMI were randomized to either DUS intermittent HMI impulses (n = 20) just prior to emergent percutaneous coronary intervention (PCI) and for an additional 30 min post-PCI (HMI + PCI), or low mechanical index (LMI) imaging only (n = 10) for perfusion assessments before and after PCI (LMI + PCI). All studies were conducted during an intravenous perflutren lipid microsphere infusion. A control reference group (n = 70) arrived outside of the time window of ultrasound availability and received emergent PCI alone (PCI only). Initial epicardial recanalization rates prior to emergent PCI and improvements in microvascular flow were compared between ultrasound-treated groups. RESULTS: Median door-to-dilation times were 82 ± 26 min in the LMI + PCI group, 72 ± 15 min in the HMI + PCI group, and 103 ± 42 min in the PCI-only group (p = NS). Angiographic recanalization prior to PCI was seen in 12 of 20 HMI + PCI patients (60%) compared with 10% of LMI + PCI and 23% of PCI-only patients (p = 0.002). There were no differences in microvascular obstructed segments prior to treatment, but there were significantly smaller proportions of obstructed segments in the HMI + PCI group at 1 month (p = 0.001) and significant improvements in left ventricular ejection fraction (p < 0.005). CONCLUSIONS: HMI impulses from a diagnostic transducer, combined with a commercial microbubble infusion, can prevent microvascular obstruction and improve functional outcome when added to the contemporary PCI management of acute STEMI. (Therapeutic Use of Ultrasound in Acute Coronary Artery Disease; NCT02410330).
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Mathias et al. (2016) conducted an RCT in ST-segment elevation myocardial infarction (STEMI) (n=100). Diagnostic ultrasound intermittent high mechanical index impulses with intravenous microbubbles vs. Low mechanical index imaging or emergent PCI alone was evaluated on Angiographic recanalization prior to PCI (p=0.002). Diagnostic ultrasound high mechanical index impulses with microbubbles improved angiographic recanalization prior to PCI compared to low mechanical index imaging (60% vs 10%, p=0.002).
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