Baroreflex effectiveness index and baroreflex sensitivity predict all-cause mortality and sudden death in hypertensive patients with chronic renal failure.
OBJECTIVE
Impaired arterial baroreflex sensitivity (BRS) has been associated with cardiac mortality and non-fatal cardiac arrests after a myocardial infarction. Patients with chronic renal failure (CRF) have a poor prognosis because of cardiovascular diseases, and sudden death is common. The aim of this study was to assess whether BRS or the baroreflex effectiveness index (BEI), a novel index reflecting the number of times the baroreflex is active in controlling the heart rate in response to blood pressure fluctuations, is associated with prognosis in CRF.


METHODS
Hypertensive patients with CRF who were treated conservatively, by haemodialysis or peritoneal dialysis were studied. Electrocardiogram and beat-to-beat blood pressures were recorded continuously and BRS and BEI were calculated. Patients were then followed prospectively for 41 +/- 15 months (range 1-64).


RESULTS
During follow-up 69 patients died. Cardiovascular diseases and uraemia accounted for the majority of deaths (60 and 20%, respectively), whereas sudden death occurred in 15 patients. In adjunct with established risk factors such as age, diabetes, congestive heart failure and diastolic blood pressure, reduced BEI was an independent predictor of all-cause mortality among CRF patients [relative risk (RR) 0.50, 95% confidence interval (CI) 0.33-0.71 for an increase of one standard deviation in BEI, P < 0.001]. Diabetes and reduced BRS were independent predictors of sudden death (RR 0.29, 95% CI 0.09-0.86 for an increase of one standard deviation in BRS, P=0.022).


CONCLUSIONS
Both BEI and BRS convey prognostic information that may have clinical implications for patients with cardiovascular diseases in general.
Johansson
Mats
M
Department of Clinical Physiology, Sahlgrenska University Hospital, Göteborg, Sweden. mats.johansson@medfak.gu.se
Gao
Sinsia A
SA
Friberg
Peter
P
Annerstedt
Marita
M
Carlström
Jan
J
Ivarsson
Ted
T
Jensen
Gert
G
Ljungman
Susanne
S
Mathillas
Oivind
O
Nielsen
Finn-David
FD
Strömbom
Ulf
U
D017704:Baroreflex; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000150:complications / Q000401:mortality / Q000503:physiopathology; D003645:Death, Sudden / Q000209:etiology*; D048909:Diabetes Complications / Q000209:etiology; D003935:Diagnostic Techniques, Cardiovascular; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors