Objectives: We aimed to investigate the frequency of venous-to-arterial circulation shunts (v-aCS), usually caused by patent foramen ovale (PFO), and thrombophilia in young adults suffering myocardial infarction (MI) and ischemic stroke (IS) and matched healthy control subjects.
Background: The cause of MI and IS in young adults is often uncertain, and paradoxical embolism might be more frequent than previously thought.
Methods: Young adults (ages 16 to 39 years) surviving MI (n = 101) and IS (n = 101) between 1993 and 1998 were matched by age and gender to 202 control subjects from the same general practitioner practices. The v-aCS were detected by transcranial Doppler after intravenous microbubble ultrasound contrast; "significant" v-aCS (> or =15 microbubble emboli) correlated with PFO on transesophageal echocardiography. A "major" v-aCS was >50 microbubbles spontaneously or >10 microbubbles spontaneously with >80 after provocation. Venous blood was taken for a thrombophilia screen.
Results: Myocardial infarction, more frequent in men, was associated with the usual cardiovascular risk factors. More women suffered IS, which was associated only with migraine and hypertension. Neither "significant" nor "major" v-aCS were associated with MI. "Major" v-aCS was found in 24 (25%) IS cases compared with 12 (12%) control subjects (odds ratio 2.80, 95% confidence interval 1.21 to 6.84; p = 0.016). Thrombophilia was not significantly associated with either MI or IS.
Conclusions: Only "major" v-aCS were associated with stroke in young adults. Closure of smaller v-aCS might not be justified.