The primary objective of this study is to assess whether adding modified-release dipyridamole to aspirin (Asasantin Retard) has measurable effects on markers of platelet function (for example, platelet aggregation) in patients with cardiovascular disease who are known to be resistant to aspirin alone

• Drug: modified-release dipyridamole/aspirin
• Drug: aspirin

Inclusion Criteria:

• Cardiovascular disease (including history of stroke or transient ischaemic attack)
• Documented evidence of resistance to aspirin
• Capable of comprehending and communicating effectively with the investigator and staff and of providing informed consent.
• Willing to give informed consent prior to participation in the trial.

Exclusion Criteria:

• Any clinically significant condition other than cardiovascular disease.
• Clinically significant abnormal baseline haematology, blood chemistry or urinalysis findings.
• Use of dipyridamole, clopidogrel, ticlopidine or any non-steroidal anti-inflammatory agent (NSAID)(including COX-2 inhibitors) during the two weeks before randomisation and during the trial.
• Active peptic ulceration or history of peptic ulcer disease.
• Known history of or suspected hypersensitivity to dipyridamole, aspirin, any NSAID or any other component of the test drugs.
• History of any bleeding disorder.
• History of cerebral haemorrhage.
• Resting seated blood pressure less than 90/60mmHg.
• Participation in any drug clinical trial within sixteen weeks prior to the start of the trial.
• Any indication of current or previous abuse of alcohol, solvents or drugs.
• Asthma.
• Pregnant or nursing women or women of childbearing potential not using a medically approved means of contraception (e.g. oral contraceptives, intrauterine devices or surgically sterile).
• Previous participation in the randomisation phase of this clinical trial.