title: Enhanced external counterpulsation improves endothelial function in patients with symptomatic coronary artery disease.
abstract: OBJECTIVE
  The goal of this study was to examine the effect of enhanced external counterpulsation (EECP) on endothelial function.
  
  
  BACKGROUND
  Enhanced external counterpulsation improves symptoms and exercise tolerance in patients with symptomatic coronary artery disease (CAD). However, the exact mechanisms by which this technique exerts its clinical benefit are unclear.
  
  
  METHODS
  Reactive hyperemia-peripheral arterial tonometry (RH-PAT), a noninvasive method to assess peripheral endothelial function by measuring reactive hyperemic response in the finger, was performed in 23 patients with refractory angina undergoing a 35-h course of EECP. In each patient RH-PAT measurements were performed before and after the first, at midcourse, and the last EECP session. In addition, RH-PAT response was assessed one month after completion of EECP therapy; RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at rest.
  
  
  RESULTS
  Enhanced external counterpulsation led to symptomatic improvement (>/=1 Canadian Cardiovascular Society class) in 17 (74%) patients; EECP was associated with a significant immediate increase in average RH-PAT index after each treatment (p < 0.05). In addition, average RH-PAT index at one-month follow-up was significantly higher than that before EECP therapy (p < 0.05). When patients were divided by their clinical response, RH-PAT index at one-month follow-up increased only in those patients who experienced clinical benefit.
  
  
  CONCLUSIONS
  Enhanced external counterpulsation enhances peripheral endothelial function with beneficial effects persisting at one-month follow-up in patients with a positive clinical response. This suggests that improvement in endothelial function may contribute to the clinical benefit of EECP in patients with symptomatic CAD.
authors.affiliation: Center for Coronary Physiology and Imaging and the Cardiac Catheterization Laboratory, Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Piero O
authors.initials: PO
authors.lastname: Bonetti
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Barsness
authors.forename: Paul C
authors.initials: PC
authors.lastname: Keelan
authors.forename: Theresa I
authors.initials: TI
authors.lastname: Schnell
authors.forename: Geralyn M
authors.initials: GM
authors.lastname: Pumper
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Kuvin
authors.forename: Robert P
authors.initials: RP
authors.lastname: Schnall
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Higano
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
mesh_terms: D000368:Aged; D001810:Blood Volume; D003327:Coronary Disease / Q000503:physiopathology* / Q000628:therapy; D015908:Counterpulsation; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005385:Fingers / Q000098:blood supply; D006801:Humans; D006940:Hyperemia; D008297:Male; D010991:Plethysmography; D011446:Prospective Studies