The purpose of the study is to examine previously examined patients with cyanotic congenital heart disease to assess how many of the patients have obtained additional blood clots since they were examined 8 years ago.

Patients with cyanotic congenital heart disease have reduced oxygen content in their blood due to abnormal connection between the heart's right and left sides. The reduced oxygenation of the blood affects several organs of the body and a common complications to the disease is blood clots. Despite the patients are young and do not have typical risk factors, previous studies have shown, that they have a very high prevalence of thrombosis in the lungs and brain.

The reason for the increased prevalence of blood clots is not known. A previous study investigated the prevalence of blood clots systematically in patients with cyanotic congenital heart disease and found that approximately 30-40% of the patients had had a clot in the lung or brain. Thus, the study could not predict, when the patient had had a thrombotic event, and most of the patients did not previously had imaging performed. Therefore the aim of this study is to re-examine previously examined cyanotic patients regardless of previous medical history, to assess how many of the patients have obtained additional blood clots since they were examined 8 years ago.

Inclusion Criteria:

• Patients with cyanotic congenital heart disease who have previously participated in the study 'cyanotic congenital heart disease: Hemostatic abnormalities and clinical manifestations' (H-KF-2006-4068).
• Clinically stable

Exclusion Criteria:

• Patients who are not guardians for themselves (not adult).
• Age <18 years.