Microcirculation and Vascular Function After Fontan Surgery

Fontan Surgery is done for children with only one working lower chamber of the heart called the 'Single Ventricle'. This surgery involves making connections between the two big veins that drain oxygen deficient blood to the heart and the lung artery directly. Fontan patients may develop long-term complications such as reduced heart function or oxygen levels, increased pressure in the veins, liver or kidney problems etc. The reasons for these complications are poorly understood. The small blood vessels in the body or 'microcirculation' are tiny (can be seen only by microscope) and they supply food and oxygen to the tissues. Very little is known about what happens to the microcirculation in adult Fontan survivors . In this study the investigator want to understand why these adult Fontan survivors develop complications by looking at their microcirculation and comparing them with healthy people and those who were operated for other congenital heart diseases. The study will be conducted in East Midlands Congenital Heart Centre, Glenfield Hospital.Leicester.

Inclusion Criteria:Patients operated for Fontan procedure or other congenital heart conditionsPatients ≥ 16 - 50 years of ageParticipant/Parents/Guardian or legal representative willing and able to give Informed Consent for participation in the studyAble (in the Investigators opinion) and willing to comply with all study requirementsExclusion Criteria:Low blood pressure (90/60 mmHg with symptoms or on intravenous inotropes for maintenance of blood pressure)Raynaud's diseaseAutoimmune diseasesDown's syndrome as they have lower risk for vascular anomalies compared with the general population and may have different microvasculatureTreatment with sympathomimetic drugsAtrial fibrillation or any other arrhythmia which might interfere with vascular function assessments.Documented peripheral vascular diseaseSkin disorders such as psoriasis or significant eczemaAny other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study.Tremor or Inability to keep the hand still for 20 minutes.Note: Patients treated with angiotensin converting enzyme inhibitors or angiotensin receptor inhibitors, beta blockers, vasodilators, diuretics and digoxin will be included in the study as the majority of Fontan survivors are taking one or more of these drugs for optimization of their circulation or for symptom management. Patients treated with anticoagulants and antiplatelets will be included in the study.