title: Coronary collateral growth by external counterpulsation: a randomised controlled trial.
abstract: BACKGROUND
  The efficacy of external counterpulsation (ECP) on coronary collateral growth has not been investigated in a randomised controlled study. Objective To test the hypothesis that ECP augments collateral function during a 1 min coronary balloon occlusion.
  
  
  METHODS
  Twenty patients with chronic stable coronary artery disease were studied. Before and after 30 h of randomly allocated ECP (20 90 min sessions over 4 weeks at 300 mm Hg inflation pressure) or sham ECP (same setting at 80 mm Hg inflation pressure), the invasive collateral flow index (CFI, no unit) was obtained in 34 vessels without coronary intervention. CFI was determined by the ratio of mean distal coronary occlusive pressure to mean aortic pressure with central venous pressure subtracted from both. Additionally, coronary collateral conductance (occlusive myocardial blood flow per aorto-coronary pressure drop) was determined by myocardial contrast echocardiography, and brachial artery flow-mediated dilatation was obtained.
  
  
  RESULTS
  CFI changed from 0.125 (0.073; interquartile range) at baseline to 0.174 (0.104) at follow-up in the ECP group (p=0.006), and from 0.129 (0.122) to 0.111 (0.125) in the sham ECP group (p=0.14). Baseline to follow-up change of coronary collateral conductance was from 0.365 (0.268) to 0.568 (0.585) ml/min/100 mm Hg in the ECP group (p=0.072), and from 0.229 (0.212) to 0.305 (0.422) ml/min/100 mm Hg in the sham ECP group (p=0.45). There was a correlation between the flow-mediated dilatation change from baseline to follow-up and the corresponding CFI change (r=0.584, p=0.027).
  
  
  CONCLUSIONS
  ECP appears to be effective in promoting coronary collateral growth. The extent of collateral function improvement is related to the amount of improvement in the systemic endothelial function.
authors.affiliation: University Hospital, CH-3010 Bern, Switzerland.
authors.forename: Steffen
authors.initials: S
authors.lastname: Gloekler
authors.forename: Pascal
authors.initials: P
authors.lastname: Meier
authors.forename: Stefano F
authors.initials: SF
authors.lastname: de Marchi
authors.forename: Tobias
authors.initials: T
authors.lastname: Rutz
authors.forename: Tobias
authors.initials: T
authors.lastname: Traupe
authors.forename: Stefano F
authors.initials: SF
authors.lastname: Rimoldi
authors.forename: Kerstin
authors.initials: K
authors.lastname: Wustmann
authors.forename: Hélène
authors.initials: H
authors.lastname: Steck
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cook
authors.forename: Rolf
authors.initials: R
authors.lastname: Vogel
authors.forename: Mario
authors.initials: M
authors.lastname: Togni
authors.forename: Christian
authors.initials: C
authors.lastname: Seiler
mesh_terms: D000787:Angina Pectoris / Q000503:physiopathology / Q000628:therapy*; D021721:Balloon Occlusion; D002908:Chronic Disease; D003097:Collateral Circulation / Q000502:physiology*; D003324:Coronary Artery Disease / Q000503:physiopathology / Q000628:therapy*; D015908:Counterpulsation / Q000379:methods*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged