Predictive value of reactive hyperemia for cardiovascular events in patients with peripheral arterial disease undergoing vascular surgery.
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.
Huang
Alex L
AL
Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass, USA.
Silver
Annemarie E
AE
Shvenke
Elena
E
Schopfer
David W
DW
Jahangir
Eiman
E
Titas
Megan A
MA
Shpilman
Alex
A
Menzoian
James O
JO
Watkins
Michael T
MT
Raffetto
Joseph D
JD
Gibbons
Gary
G
Woodson
Jonathan
J
Shaw
Palma M
PM
Dhadly
Mandeep
M
Eberhardt
Robert T
RT
Keaney
John F
JF
Gokce
Noyan
N
Vita
Joseph A
JA
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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