Serum complement activation in congestive heart failure.
BACKGROUND
Although activation of the complement system in myocardial infarction and cardiopulmonary bypass has been shown to contribute to myocardial injury, its role in congestive heart failure (CHF) is unknown. The purpose of this study was to determine the presence of terminal complement activation and its relation to clinical outcomes in patients with CHF.


METHODS
We measured serum levels of the terminal complement complex C5b-9 in 36 patients with symptomatic heart failure and left ventricular ejection fraction <40%. We compared the serum C5b-9 levels of these patients with CHF with a group of 12 age-matched control patients. Combined clinical outcomes (death, urgent heart transplantation, or hospitalization with worsening heart failure) at 6 months were determined.


RESULTS
The serum C5b-9 [median (25th to 75th percentiles)] levels in 36 patients with CHF [101.5 ng/mL (40 to 164)] were significantly (P =.003) higher than in the 12 control patients [36.5 ng/mL (22 to 50)]. Significantly more of the patients with CHF with the highest levels of C5b-9 (highest 50th percentile) had New York Heart Association class IV symptoms (67% vs 33%; P =.04) and adverse clinical outcomes by 6 months (56% vs 17%; P =.02) compared with the patients with CHF with lower levels (lowest 50th percentile).


CONCLUSIONS
We have described a significant elevation in circulating C5b-9, the terminal complement complex, in patients with symptomatic heart failure and have observed an association between high levels of C5b-9 and near-term adverse events.
Section of Cardiovascular Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
D J
DJ
Clark
M W
MW
Cleman
S E
SE
Pfau
S A
SA
Rollins
T M
TM
Ramahi
C
C
Mayer
T
T
Caulin-Glaser
E
E
Daher
M
M
Kosiborod
L
L
Bell
J F
JF
Setaro
D000368:Aged; D003167:Complement Activation; D015938:Complement Membrane Attack Complex / Q000032:analysis*; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D015938:Complement Membrane Attack Complex; D014409:Tumor Necrosis Factor-alpha