Serum lipoprotein(a) concentrations and apolipoprotein(a) isoforms: association with the severity of clinical presentation in patients with coronary heart disease.
OBJECTIVE
The aim of this study was to investigate the possible associations between lipoprotein(a) [Lp(a)] concentrations or apolipoprotein(a) isoforms and the mode of clinical presentation of coronary heart disease (CHD) (acute thrombotic event or not).


METHODS
A total of 131 CHD patients and 71 age- and gender-matched individuals without known CAD (free of symptoms of heart disease) were enrolled in the study. CHD patients were classified into patients with a history of an acute coronary syndrome (ACS, n=94) and patients with stable angina (SA, n=37). Lp(a) levels were measured with an ELISA method, whereas apolipoprotein(a) isoform analysis was performed (in all patients and 33 controls) by electrophoresis in 1.5% SDS-agarose gels followed by immunoblotting. Isoform size was expressed as the number of kringle 4 (K4) repeats.


RESULTS
ACS patients had higher Lp(a) plasma levels 121.9 (0.8-84.1) mg/dl] and a greater proportion of elevated (> or = 30 mg/dl) Lp(a) concentrations (25.5%) compared with SA patients [9.2 (0.8-50.5) mg/dl, P < 0.01 and 10.8%, P < 0.05] and controls [8.0 (0.8-55.0) mg/dl, P < 0.01 and 11.2%, P < 0.05], while there were no differences between SA patients and controls. The median apolipoprotein(a)-isoform size was 26 K4. In 17 (10%) patients we could not detect any apolipoprotein(a) isoform bands by immunoblotting. ACS patients had a higher proportion of isoforms < 26 K4 (low molecular weight) than SA patients (56/85 vs. 12/33, P < 0.005) and controls (10/29, P < 0.005).


CONCLUSIONS
CAD patients with a history of ACS have higher Lp(a) plasma levels and a significantly higher proportion of low molecular weight apolipoprotein(a) isoforms compared with patients with SA or to controls.
Katsouras
C S
CS
Department of Cardiology, Medical School, University of Ioannina, Greece.
Karabina
S A
SA
Tambaki
A P
AP
Goudevenos
J A
JA
Michalis
L K
LK
Tsironis
L D
LD
Stroumbis
C S
CS
Elisaf
M S
MS
Sideris
D A
DA
Tselepis
A D
AD
D000208:Acute Disease; D000368:Aged; D001053:Apolipoproteins / Q000097:blood*; D053241:Apoprotein(a); D003327:Coronary Disease / Q000097:blood*; D005260:Female; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020033:Protein Isoforms / Q000097:blood; D012720:Severity of Illness Index; D013577:Syndrome
D001053:Apolipoproteins; D017270:Lipoprotein(a); D020033:Protein Isoforms; D053241:Apoprotein(a)