Short summary

It is known that left atrial (LA) size may be associated with atrial fibrillation (AF) and increased risk of thromboembolic disease. From the Danish Cardiovascular Screening trial (DANCAVAS) approximately 12.000 cardiac CT are available. This project aims to examine the association between LA size measured by CT and AF, and furthermore to examine if LA size acts as a risk factor of thromboembolic disease.

Rationale

Atrial Fibrillation (AF) is a major cause of stroke and systemic embolism, and many patients receive anticoagulants. However, some patients may experience serious adverse effects from the medication such as bleeding; therefore it is important to differentiate between high and low risk patients.

Studies have shown that enlarged left atrial (LA) size is associated with AF and cardiovascular disease, and LA size may be associated with increased risk of thromboembolic disease.

The expression of different microRNAs reflects an ongoing pathological condition, and microRNA therefor holds potential as a novel diagnostic tool in patients with AF.

Objectives:

1. To examine if LA size measured by non-contrast CT is reliable.
2. To assess the association between LA size measured by CT and AF, and to explore the potential association between microRNA, fibrosis biomarkers and AF.
3. To examine if enlarged LA size acts as an independent risk factor of thromboembolic disease

Description of the cohort

In the Danish Cardiovascular Screening trial (DANCAVAS) all Danish men aged 65-74 years living on the Island of Funen or in the surrounding communities of Vejle and Silkeborg were randomized, and one-third were invited for a cardiovascular screening program. A total of approximately 12.000 participants will undergo cardiac CT.

Plasma analysis for miRNA and biomarkers of fibrosis are performed in 100 patients with current AF, 100 with incident AF, and compared to 100 healthy controls from the DANCAVAS population.

Data and biological material

The cardiovascular screening program includes: 1) low-dose NCCT scan to detect CAC and aortic/iliac aneurysms, 2) brachial and ankle blood pressure index to detect peripheral arterial disease and hypertension, 3) a telemetric assessment of the heart rhythm, and 4) a measurement of the cholesterol and plasma glucose levels

Current AF is available from the DANCAVAS database, and LA size is measured from CT. After at least a year follow-up the cohort is examined for incident AF using data available from The Danish National Patient Register. Furthermore the entire DANCAVAS cohort are examined for thromboembolic disease in registry-data (the Danish National Patient Register, the Danish Stroke Register and the Danish Vascular Registry) after at least a year follow-up

Collaborating researchers and departments

Department of Cardiology, Odense University Hospital

• PhD-student Maise Fredgart
• Associate professor Axel Diederichsen
• Associate professor Axel Brandes
• Professor Jacob Eifer Møller

Department of Cardiothoracic and Vascular Surgery, Odense University Hospital

• Professor Jes Lindholt

Department of Clinical Biochemistry and Pharmacology, Odense University Hospital

• Professor Lars Melholt Rasmussen

Department of Cardiology, Sygehus Lillebælt

• Flemming Hald Steffensen
• Jess Lambrechtsen

Department of Cardiology, Silkeborg Hospital

• Lars Frost

West-German Heart and Vascular Center, Essen, Germany

• Professor Raimund Erbel