title: Coronary and microvascular physiology during intra-aortic balloon counterpulsation.
abstract: OBJECTIVE
  This study sought to identify the effect of coronary autoregulation on myocardial perfusion during intra-aortic balloon pump (IABP) therapy.
  
  
  BACKGROUND
  IABP is the most commonly used circulatory support device, although its efficacy in certain scenarios has been questioned. The impact of alterations in microvascular function on IABP efficacy has not previously been evaluated in humans.
  
  
  METHODS
  Thirteen patients with ischemic cardiomyopathy (left ventricular ejection fraction: 34 ± 8%) undergoing percutaneous coronary intervention were recruited. Simultaneous intracoronary pressure and Doppler-flow measurements were undertaken in the target vessel following percutaneous coronary intervention, during unassisted and IABP-assisted conditions. Coronary autoregulation was modulated by the use of intracoronary adenosine, inducing maximal hyperemia. Wave intensity analysis characterized the coronary wave energies associated with balloon counterpulsation.
  
  
  RESULTS
  Two unique diastolic coronary waves were temporally associated with IABP device use; a forward compression wave and a forward expansion wave caused by inflation and deflation, respectively. During basal conditions, IABP therapy increased distal coronary pressure (82.4 ± 16.1 vs. 88.7 ± 17.8 mm Hg, p = 0.03), as well as microvascular resistance (2.32 ± 0.52 vs. 3.27 ± 0.41 mm Hg cm s(-1), p = 0.001), with no change in average peak velocity (30.6 ± 12.0 vs. 26.6 ± 11.3 cm s(-1), p = 0.59). When autoregulation was disabled, counterpulsation caused an increase in average peak velocity (39.4 ± 10.5 vs. 44.7 ± 17.5 cm s(-1), p = 0.002) that was linearly related with IABP-forward compression wave energy (R(2) = 0.71, p = 0.001).
  
  
  CONCLUSIONS
  Autoregulation ameliorates the effect of IABP on coronary flow. However, during hyperemia, IABP augments myocardial perfusion, principally due to a diastolic forward compression wave caused by balloon inflation, suggesting IABP would be of greatest benefit when microcirculatory reserve is exhausted.
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Kalpa
authors.initials: K
authors.lastname: De Silva
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lumley
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Balrik
authors.initials: B
authors.lastname: Kailey
authors.affiliation: Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas's Hospital, London, United Kingdom.
authors.forename: Jordi
authors.initials: J
authors.lastname: Alastruey
authors.affiliation: Department of Clinical Pharmacology, St. Thomas's National Health Service Foundation Trust, London, United Kingdom.
authors.forename: Antoine
authors.initials: A
authors.lastname: Guilcher
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Kaleab N
authors.initials: KN
authors.lastname: Asrress
authors.affiliation: Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas's Hospital, London, United Kingdom; Multidisciplinary Cardiovascular Research Centre, Leeds Institute of Genetics, Health and Therapeutics University of Leeds, Leeds, United Kingdom.
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Marber
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Redwood
authors.affiliation: King's College London British Heart Foundation Centre of Excellence, National Institute for Health Research Biomedical Research Centre at Guy's and St. Thomas's National Health Service Foundation Trust, Cardiovascular Division, The Rayne Institute, London, United Kingdom. Electronic address: Divaka.Perera@kcl.ac.uk.
authors.forename: Divaka
authors.initials: D
authors.lastname: Perera
mesh_terms: D000368:Aged; D001794:Blood Pressure; D003326:Coronary Circulation / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007423:Intra-Aortic Balloon Pumping / Q000379:methods*; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: intra-aortic balloon pump; left ventricular dysfunction; microvascular function; wave intensity analysis