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Aspirin Resistance Testing in Patients 12 to 18 Months After Heart Transplantation Treated with Acetylsalicylic Acid

Verified siteRegistered drugNo placebo

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is studying people who have had a heart transplantation and are taking acetylsalicylic acid (aspirin) as Thrombo ASS 100 mg-Filmtabletten. The purpose of the study is to check how often aspirin resistance happens in this group. Aspirin resistance means that the medicine may not work as expected to help prevent blood clots.

In the study, blood testing is done during a follow-up visit after the transplant. The tests are used to see how the platelets, which are small blood cells that help blood clot, respond to aspirin. The study looks at patients about 12 to 18 months after heart transplantation and compares the blood test results with health details such as age, sex, diabetes, high blood pressure, smoking, past rejection episodes, infections, and cholesterol levels.

The study does not use a new treatment. It focuses on testing the effect of the aspirin already being taken after heart transplantation. The results are intended to improve understanding of how well aspirin works in this setting.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

Step 1
Study entry
After you join the study, you take part in a single outpatient assessment of platelet function. platelet function means how well your blood cells that help stop bleeding are working.
You are included in this assessment because you have had a heart transplant and are taking aspirin therapy.
Step 2
Aspirin treatment during the study
You continue taking acetylsalicylic acid by mouth. the study product is Thrombo ASS 100 mg, which is a gastro-resistant tablet. gastro-resistant means the tablet is made to pass through the stomach before it dissolves.
The dose is 100 mg once daily. the study is focused on patients who are 12 to 18 months after heart transplantation, and the assessment is performed during this period.
Step 3
Blood or platelet function testing
During the study visit, your platelet function is tested to check for aspirin resistance. aspirin resistance means that aspirin may not be working as expected to affect platelet function.
The main test used to define aspirin resistance is the Multiplate® ASPI test. additional tests may also be used: Innovance® PFA-200 System Analyzer and VerifyNow®.
Step 4
Collection of health information
Information is recorded about your age, sex, body mass index (BMI, a measure of body weight compared with height), smoking status, diabetes, high blood pressure, rejection episodes, cardiovascular events or stroke since heart transplantation, CRP (c-reactive protein, a blood marker of inflammation), cancer, intensive care unit stay after heart transplantation, CMV infection, physical activity, and cholesterol and triglyceride values.
This information is used together with the test results to assess the presence of aspirin resistance.
Step 5
End of study participation
After the study assessments are completed, your participation in this trial ends.
The study period as a whole is planned from 2026-04-01 to 2028-06-30.

Who can join the trial?

3 criteria

Adults aged 18 to 99 years.
Patients who are taking aspirin therapy, meaning they are using aspirin as a regular treatment.
Patients who had a heart transplantation between 12 and 18 months before joining the study.

Who cannot join the trial?

4 criteria

People who have had a heart transplant are not eligible.
People with a platelet count lower than 100,000/µL are not eligible. Platelets are blood cells that help the blood clot.
People who are pregnant are not eligible.
People who are breastfeeding are not eligible.

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Verified sites

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Medical University Of Vienna
Verified
Vienna, Austria

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Investigated drugs

Aspirin is the study medicine used in this trial. It is taken by mouth and is meant to help stop blood clots from forming by making platelets less sticky. In this study, researchers are checking how well aspirin works in people who have had a heart transplant and are already using aspirin therapy. The goal is to see whether some patients may not respond to aspirin as expected, which is sometimes called aspirin resistance.

Acetylsalicylic Acid

What is already known about the treatment

Acetylsalicylic acid - Acetylsalicylic acid is taken by mouth as a gastro-resistant tablet, which helps protect the stomach and lets the medicine pass into the intestine before dissolving. It is a well-known and widely used medicine in modern practice and medical literature, especially for preventing blood clots in people at risk of heart and blood vessel problems. Its main use is to lower the chance of heart attack, stroke, and other clot-related problems, and in this trial it is being used after heart transplantation to help keep blood platelets from sticking together too much. At the molecular level, it blocks an enzyme called cyclooxygenase, which reduces the making of thromboxane, a substance that normally helps platelets clump together; it is classified as an antiplatelet medicine and also as a nonsteroidal anti-inflammatory drug.

Investigated diseases

Heart transplantation - Heart transplantation is a surgical replacement of a failing heart with a healthy donor heart. After the operation, the body may slowly adapt to the new heart over time, and the person must be monitored for signs that the body is reacting against the transplanted organ. Some people may later develop periods of rejection, changes in heart function, or other heart-related problems.