Left Atrial Volume Index in Asymptomatic Aortic Stenosis

Study Overview
=================
Brief Summary
-----------------
Aortic stenosis results in increased filling pressures of the heart. Size and function of the left atrium may be a marker for more advanced heart disease (heart failure) in patients with severe aortic stenosis, not presenting any apparent symptoms. The goal of this study is to establish the importance and possible implications of left atrial dilation in asymptomatic patients with aortic valve stenosis.

Detailed Description
-----------------
Aortic valve stenosis (AS) is the most common valvular disease in the western world. Mild and moderate AS generally is well tolerated severe AS is associated with considerable morbidity and mortality. The consequence of AS is increased pressure load on the left ventricle, which causes changes in the ventricular function and structure (Left ventricular remodeling, hypertrophy, fibrosis). With longstanding elevated filling pressures the left atrium will dilate and heart failure symptoms will develop. When apparent, symptoms of heart failure, in AS are associated with high mortality rate and aortic valve replacement (AVR) is recommended. The clinical assessment of heart failure symptoms in AS is however challenging particularly in the elderly, as symptoms progress slowly and may mimic age related fragility. In this observational study, the goal is to investigate the importance and possible implications of left atrial dilation and heart failure among 100 patients with asymptomatic severe aortic stenosis. Participants undergo echocardiographic evaluation for diastolic heart failure and we assess myocardial fibrosis using magnetic resonance imaging and exercise testing with invasive hemodynamic monitoring (right heart catheterization). LA dilatation may potentially identify patients likely benefiting of early surgery. The importance and possible implications of LA dilatation in asymptomatic AS patients has however not yet been established.

Official Title
-----------------
Left Atrial Volume Index - Impact on LV Remodeling, LV Function and Functional Capacity in Asymptomatic Aortic Valve Stenosis

Conditions
-----------------
Aortic Valve Stenosis, Heart Failure

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Asymptomatic severe aortic stenosis (Vmax > 3.5 m/sec and aortic valve area < 1 cm2). Exclusion Criteria: Moderate LV systolic dysfunction (LVEF < 50%) Concomitant moderate-severe aortic valve regurgitation Concomitant moderate-severe mitral valve regurgitation Moderate to severe nephropathy Chronic or persistent atrial fibrillation Implanted pacemaker or cardio defibrillator Disability to exercise testing.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional Capacity | Differences in functional capacity reflected by atrial size. An incremental maximal exersice test to determine maximal whole-body oxygen uptake (VO2-max) will be performed. On a cycle ergometer VO2 and VCO2 are measured continuously with a breath-by-breath pulmonary exchange system. Following the warm up, the resistance is increased every 2 minutes for 3 bouts, where after the resistance increases every minute (10% increments in VO2-max). The test is terminated 30 seconds after the subjects are unable to maintain 60 revolutions pr. min, but are still able to bike. A horizontal plateau on the oxygen uptake graph demarks the maximal oxygen uptake in liters pr. min. This is divided by their body mass, to obtain maximal oxygen uptake pr. mass unit pr. time unit. | 2 years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Aortic Valve Stenosis, Functional Capacity, Cardiomyopathies, Endomyocardial Fibrosis, Cardiovascular Diseases, Heart Diseases, Heart Valve Diseases, Atrial Fibrillation, Hypertrophy, Hypertrophy, Left Ventricular, Diastology