Aspirin in Patients With Myocardial Infarction and Thrombocytopenia

Primary Objective:

To determine the risk of bleeding from ASA therapy in thrombocytopenic patients who develop Acute Coronary Syndrome (ACS), and assess its effect on the overall morbidity and mortality in these patients as well as platelet functions.

Aspirin is known to decrease death rate by as much as 50% in patients that suffer from heart attacks. Patients with low platelet count are not given aspirin for fear of an increased risk of bleeding. Researchers want to compare the risks versus the benefits of using aspirin in this patient population.

Participants in this study who suffer chest pain will be treated with a single enteric coated aspirin 325 mg instead of the current treatment without aspirin. Participants will then be tested to confirm that they had a heart attack by EKG (a test to measure the electrical activity of the heart) and blood tests (5ml of blood) will be drawn every 8 hours to detect enzymes that are released from the heart due to the heart attack. Blood samples will also be examined for platelet number.

Participants who are found to have had a heart attack and have a platelet count of between 100,000 and 20,000 will be continued on aspirin (160 mg per day). All other standard medications for heart attacks will also be given.

Participants who are found to have had a heart attack but whose platelet number is more than 100,000 will be given the standard therapy for heart attack, including enteric coated aspirin 325 mg per day, and will no longer take part in this study. Participants who are found to have had a heart attack but whose platelet number is less than 20,000 will be not be included in the study and will be treated as deemed appropriate by their primary physician.

Participants will be examined daily and evaluated for bleeding. Blood samples (30 ml of blood) will also be drawn before or after aspirin is given and 24 hours, 72 hours and 7 days after aspirin treatment to study platelet function. Participants will be followed up on the study for 7 days. Participants will be followed up in the cardiology clinic within 1-2 weeks after discharge from the hospital, then once a month for six month. Further follow up will be every 6 month. Patients are requested to follow up with cardiology by phone at any time for any bleeding.

Participants who are not found to have had a heart attack will not receive any further aspirin treatment.

This is an investigational study. Aspirin is an FDA approved drug for treatment of heart attacks and is commercially available. Aspirin is a standard therapy for patients who have had a heart attack. Thirty patients will take part in this study. All will be enrolled at M. D. Anderson.

Eligibility Criteria:
Inclusion Criteria:

1. Presenting for Cardiology consult at M.D. Anderson Cancer Center.
2. Platelet count between 100,000 and 20,000.
3. Acute Coronary Syndrome diagnosed with their first 12 lead EKG.
4. Patients that continue to show evidence of MI by cardiac enzymes with CPK levels \> 2 normal limits, CK-MB levels 10% above normal limits, and Troponin I levels \> 1.4ug/L will be considered positive for MI.
5. Ability to give consent.

Exclusion Criteria:

1. Contraindications to aspirin including severe intolerance or true allergy, active bleeding, hemophilia, active retinal bleeding, severe untreated hypertension, active peptic ulcer, or other significant source of gastrointestinal or genitourinary bleeding, brain metastasis, and altered mental status.
2. Unwillingness or inability to give consent.
3. Progressive heart failure, unstable angina not responding to medical therapy for 24 hours, or ventricular tachycardia, necessitating thrombolysis, and angioplasty.
4. Patients that rule out for MI by cardiac enzymes panel after the first 24 hours.
5. Patients that rule in for MI and have Platelet count \> 100,000.
6. Patients with platelet count \< 20,000.