Persistent activation of coagulation mechanism in unstable angina and myocardial infarction.
BACKGROUND
The blood coagulation system is activated in the acute phase of unstable angina and acute myocardial infarction. However, it remains unclear whether augmented function of the hemostatic mechanism serves only as a marker of the acute thrombotic episode or whether a hypercoagulable state persists for a prolonged period after clinical stabilization.


RESULTS
We prospectively measured the plasma concentrations of prothrombin fragment 1 + 2 (F1 + 2) and fibrinopeptide A (FPA) in consecutive patients presenting with unstable angina (n = 81) or acute myocardial infarction (n = 32), respectively. At 6 months, plasma determinations were repeated in patients experiencing an uneventful clinical course (unstable angina, n = 57; myocardial infarction, n = 23). We quantitated the plasma levels of F1 + 2 and FPA in control patients with stable angina (n = 37) or healthy individuals (n = 32) who were matched for age and sex. The median plasma concentrations of F1 + 2 and FPA are significantly higher in patients presenting with unstable angina (F1 + 2, 1.08 nmol/L; FPA, 2.4 nmol/L) or acute myocardial infarction (F1 + 2, 1.27 nmol/L; FPA, 3.55 nmol/L) compared with patients with stable angina (F1 + 2, 0.74 nmol/L; FPA, 1.3 nmol/L; P < .0001) or healthy individuals (F1 + 2, 0.71 nmol/L; FPA, 0.80 nmol/L; P < .0001). At 6 months, the median plasma levels of F1 + 2 in patients exhibiting an uneventful clinical course did not differ from values obtained at admission (unstable angina, 1.26 versus 1.07 nmol/L, P = NS; myocardial infarction, 1.22 versus 1.29 nmol/L, P = NS), whereas the median plasma levels of FPA in the same two subpopulations were significantly reduced (unstable angina, 1.1 versus 2.9 nmol/L, P = .0003; myocardial infarction, 1.1 versus 3.0 nmol/L; P = .0028).


CONCLUSIONS
During the acute phase of unstable angina and myocardial infarction, patients exhibit increased coagulation system activity. Over the next 6 months, patients with unstable angina or myocardial infarction experiencing an uneventful clinical course manifest a persistent hypercoagulable state with minimal generation of fibrin.
2nd Division of Cardiology, Ca'Granda Niguarda Hospital, Milan, Italy.
P A
PA
Merlini
K A
KA
Bauer
L
L
Oltrona
D
D
Ardissino
M
M
Cattaneo
C
C
Belli
P M
PM
Mannucci
R D
RD
Rosenberg
D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000097:blood; D000789:Angina, Unstable / Q000097:blood*; D001777:Blood Coagulation / Q000502:physiology*; D005260:Female; D005344:Fibrinopeptide A / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000032:analysis; D011446:Prospective Studies; D011516:Prothrombin / Q000032:analysis; D012016:Reference Values
D010446:Peptide Fragments; C045879:prothrombin fragment 1.2; D005344:Fibrinopeptide A; D011516:Prothrombin