Relation between ST segment shifts during ischemia and thrombin activity in patients with unstable angina
P R Eisenberg1, J L Kenzora, B E Sobel
1Cardiovascular Division, Washington University School of Medicine, Washington University Medical Center, St. Louis, Missouri.
Insights
In unstable angina patients, elevated fibrinopeptide A indicates increased thrombin activity. Reversible ST segment shifts suggest ongoing thrombosis, benefiting from antithrombotic therapy.
Area of Science:
- Cardiology
- Hematology
- Biochemistry
Background:
- Unstable angina is a critical condition often linked to acute coronary thrombosis.
- Assessing ongoing thrombotic activity is crucial for guiding treatment decisions in unstable angina.
Purpose of the Study:
- To investigate the correlation between specific electrocardiographic (ECG) abnormalities and recurrent ischemia in unstable angina patients with increased thrombin activity.
- To determine if plasma fibrinopeptide A concentrations reflect thrombin activity in these patients.
Main Methods:
- Plasma fibrinopeptide A concentrations were measured in 29 patients with unstable angina.
- ECG findings (ST segment shifts, T wave abnormalities) and coronary angiography results were analyzed.
- Correlations between ECG findings, angiographic evidence of thrombosis, and fibrinopeptide A levels were assessed.
Main Results:
- Overall plasma fibrinopeptide A levels were elevated in unstable angina patients.
- Patients with reversible ST segment shifts showed significantly higher fibrinopeptide A levels compared to those with only T wave abnormalities.
- A higher proportion of patients with ST segment shifts had angiographic evidence of coronary thrombosis.
Conclusions:
- Reversible ST segment shifts in unstable angina are associated with increased thrombin activity and likely ongoing thrombosis.
- These findings identify a subgroup of patients who may benefit from antithrombotic therapies.
Abstract:
This study was designed to determine in patients with unstable angina whether specific electrocardiographic abnormalities associated with ischemia, the presence of coronary lesions consistent with thrombosis on angiography or the presence of recurrent ischemia reflects increases in thrombin activity as manifested by increased plasma concentrations of fibrinopeptide A. The concentration of fibrinopeptide A in plasma was increased to 6.7 +/- 3.1 nM for the group as a whole (n = 29). Increases were greater in the 17 patients who exhibited reversible ST segment shifts (10.2 +/- 5.2 nM) than in the 12 patients exhibiting reversible T wave abnormalities alone (1.6 +/- 0.2 nM) (p less than 0.01). Nine of the 17 patients with reversible ST segment shifts who underwent coronary angiography had lesions with morphologic characteristics consistent with atherosclerotic plaque complicated by thrombosis compared with only 2 of 9 patients with T wave changes only (p less than 0.05). Plasma concentrations of fibrinopeptide A were markedly elevated in 7 of the 11 patients in whom complex lesions were noted on angiographic examination. Thus, the occurrence of reversible ST segment shifts identifies a group of patients with unstable angina in whom ongoing thrombosis is likely and who may be particularly likely to benefit from antithrombotic therapy.
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