title: Diagnostic Ultrasound Impulses Improve Microvascular Flow in Patients With STEMI Receiving Intravenous Microbubbles.
abstract: 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).
  
  
  OBJECTIVE
  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).
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil. Electronic address: wmathias@incor.usp.br.
authors.forename: Wilson
authors.initials: W
authors.lastname: Mathias
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Jeane M
authors.initials: JM
authors.lastname: Tsutsui
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Bruno G
authors.initials: BG
authors.lastname: Tavares
authors.affiliation: Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Miguel O D
authors.initials: MO
authors.lastname: Aguiar
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Diego R
authors.initials: DR
authors.lastname: Garcia
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Mucio T
authors.initials: MT
authors.lastname: Oliveira
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Soeiro
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Jose C
authors.initials: JC
authors.lastname: Nicolau
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Lemos
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Rochitte
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: José A F
authors.initials: JA
authors.lastname: Ramires
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Kalil
authors.affiliation: Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Porter
mesh_terms: D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000628:therapy; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D061185:Mechanical Thrombolysis / Q000379:methods*; D045423:Microbubbles; D008833:Microcirculation; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention; D000072657:ST Elevation Myocardial Infarction / Q000628:therapy*; D013318:Stroke Volume; D014464:Ultrasonic Therapy
keywords: acute myocardial infarction; microvascular obstruction; ultrasound therapy