title: Predictive value of reactive hyperemia for cardiovascular events in patients with peripheral arterial disease undergoing vascular surgery.
abstract: OBJECTIVE
  Reactive hyperemia is the compensatory increase in blood flow that occurs after a period of tissue ischemia, and this response is blunted in patients with cardiovascular risk factors. The predictive value of reactive hyperemia for cardiovascular events in patients with atherosclerosis and the relative importance of reactive hyperemia compared with other measures of vascular function have not been previously studied.
  
  
  RESULTS
  We prospectively measured reactive hyperemia and brachial artery flow-mediated dilation by ultrasound in 267 patients with peripheral arterial disease referred for vascular surgery (age 66+/-11 years, 26% female). Median follow-up was 309 days (range 1 to 730 days). Fifty patients (19%) had an event, including cardiac death (15), myocardial infarction (18), unstable angina (8), congestive heart failure (6), and nonhemorrhagic stroke (3). Patients with an event were older and had lower hyperemic flow velocity (75+/-39 versus 95+/-50 cm/s, P=0.009). Patients with an event also had lower flow-mediated dilation (4.5+/-3.0 versus 6.9+/-4.6%, P<0.001), and when these 2 measures of vascular function were included in the same Cox proportional hazards model, lower hyperemic flow (OR 2.7, 95% CI 1.2 to 5.9, P=0.018) and lower flow-mediated dilation (OR 4.2, 95% CI: 1.8 to 9.8, P=0.001) both predicted cardiovascular events while adjusting for other risk factors.
  
  
  CONCLUSIONS
  Thus, lower reactive hyperemia is associated with increased cardiovascular risk in patients with peripheral arterial disease. Furthermore, flow-mediated dilation and reactive hyperemia incrementally relate to cardiovascular risk, although impaired flow-mediated dilation was the stronger predictor in this population. These findings further support the clinical relevance of vascular function measured in the microvasculature and conduit arteries in the upper extremity.
authors: Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass, USA.
authors: Alex L
authors: AL
authors: Huang
authors: Annemarie E
authors: AE
authors: Silver
authors: Elena
authors: E
authors: Shvenke
authors: David W
authors: DW
authors: Schopfer
authors: Eiman
authors: E
authors: Jahangir
authors: Megan A
authors: MA
authors: Titas
authors: Alex
authors: A
authors: Shpilman
authors: James O
authors: JO
authors: Menzoian
authors: Michael T
authors: MT
authors: Watkins
authors: Joseph D
authors: JD
authors: Raffetto
authors: Gary
authors: G
authors: Gibbons
authors: Jonathan
authors: J
authors: Woodson
authors: Palma M
authors: PM
authors: Shaw
authors: Mandeep
authors: M
authors: Dhadly
authors: Robert T
authors: RT
authors: Eberhardt
authors: John F
authors: JF
authors: Keaney
authors: Noyan
authors: N
authors: Gokce
authors: Joseph A
authors: JA
authors: Vita
mesh_terms: D000367:Age Factors; D000368:Aged; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008833:Microcirculation / Q000503:physiopathology; D008875:Middle Aged; D016017:Odds Ratio; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012039:Regional Blood Flow; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014463:Ultrasonography; D014656:Vascular Surgical Procedures / Q000009:adverse effects*; D014664:Vasodilation
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