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The effects of trapidil on left ventricular function and platelet aggregation in patients with coronary artery
A Kurita1, K Satomura, S Kawaguchi
1National Defense Medical College, Department of Internal Medicine, Saitama, Japan.
Insights
Trapidil, an antianginal agent, improved hemodynamics and reduced chest pain in coronary artery disease patients by decreasing blood pressure and left ventricular end-diastolic pressure. It also suppressed myocardial lactate production and beta-thromboglobulin levels.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Coronary artery disease (CAD) poses significant risks, often leading to angina and impaired cardiac function.
- Antianginal agents are crucial for managing symptoms and improving outcomes in CAD patients.
Purpose of the Study:
- To evaluate the effects of intravenous trapidil on cardiac function, hemodynamics, and myocardial metabolism in patients with CAD.
- To assess trapidil's efficacy in preventing pacing-induced angina and its impact on platelet aggregation.
Main Methods:
- 12 CAD patients received 100 mg of intravenous trapidil.
- Hemodynamic parameters, coronary sinus blood flow, myocardial lactate metabolism, and platelet aggregation were measured before and after pacing.
- Pacing was performed with and without trapidil administration.
Main Results:
- Trapidil reduced mean blood pressure and left ventricular end-diastolic pressure at rest and post-pacing.
- Pacing-induced angina and ST-segment depression were significantly reduced after trapidil administration.
- Trapidil suppressed myocardial lactate production and decreased beta-thromboglobulin levels, without affecting platelet aggregation.
- Coronary sinus blood flow and max dp/dt increased slightly, while diastolic function remained unaffected.
Conclusions:
- Trapidil demonstrates beneficial systemic hemodynamic effects in CAD patients, reducing preload and afterload.
- The drug effectively alleviates angina symptoms and improves myocardial function during stress.
- Trapidil may inhibit platelet-derived growth factors, potentially offering protection against atherosclerosis.
Abstract:
The effects of the intravenous administration of 100 mg of trapidil on systolic and diastolic left ventricular functions and coronary sinus blood flow, as well as on myocardial lactate metabolism and platelet aggregation, were investigated before and after pacing in 12 patients with coronary artery disease. Pacing without administration of trapidil provoked angina in 6 of these patients. During rest, trapidil decreased the mean blood pressure by an average of 5 mmHg (from 112 +/- 15 to 107 +/- 8 mmHg, p less than 0.05) and the left ventricular end-diastolic pressure by an average of 4 mmHg (from 10 +/- 3 to 6 +/- 2 mmHg, p less than 0.05). Trapidil also caused both the max dp/dt and the coronary sinus blood flow to increase slightly, although it had no significant effect on diastolic function, myocardial lactate metabolism, or platelet aggregation. During the pacing that followed trapidil administration, chest pain was not provoked in the same 6 patients who had previously experienced chest pain on pacing. The extent of ST-segment depression also improved from -1.6 +/- 0.3 to -0.9 +/- 0.7 mm (p less than 0.05) and there was a significant suppression of the production of myocardial lactate. When pacing was terminated, trapidil caused a decrease in left ventricular systolic pressure from 173 to 156 mmHg (p less than 0.05), and also caused a decrease of the left ventricular end-diastolic pressure, from 16 +/- 4 to 8 +/- 2 mmHg (p less than 0.05). Trapidil had no significant effect on platelet aggregation activity with either a 1 microM or a 2 microM dose of ADP (adenosine diphosphate). However, the beta-TG level was suppressed, decreasing from 119 +/- 14 to 99 +/- 19 ng/ml in the arterial blood (p less than 0.1) and from 114 +/- 9 to 103 +/- 17 ng/ml (p less than 0.1) in the coronary sinus blood. Reductions in the preload and afterload by trapidil were of far greater magnitude than either its coronary dilatory or positive chronotropic effects in patients with coronary artery disease. Thus trapidil, a new antianginal agent appears to inhibit the production of platelet derived growth factors and may, therefore, protect the arteries from atherosclerosis as it promotes beneficial systemic hemodynamics in patients with depressed ventricular function.