Effects of Exercise on Thoracic Aneurysms

Thoracic aneurysm incidence is estimated to 4.5 cases per 100 000. The manifestation as well as natural history of thoracic aneurysm depend on many factors such as its localisation, its diameter, presence of collagen disease and family history. For the ascendant aortic aneurysm, it is often linked to a degeneration of the media arterial layer of the arterial wall. The media degeneration is cause by the degeneration of the elastic fibres, which lead to a weakening of the arterial wall accompanied with dilation. This process is often due to age and is accelerated by high blood pressure. Amongst the numerous factors causing the aneurysm, the investigators find: hypertension, aortic bicuspid valve, smoking, atherosclerosis, trauma and genetic predisposition. The average growth rate of thoracic aneurysm is 0.1-0.2 cm/year. The risk of rupture is associated to the size of the aneurysm as well as patient's symptoms. The ruptures and dissections rates are accounted for 2-3/year for thoracic aneurysm between 5.5-6.0 cm in diameter. The patients are often limited in their daily life activities considering their concern and risk of rupture and/or dissect. The effects of exercise on the progression of the aneurysm dilation in patients with thoracic ascendant aortic aneurysm are unknown. It is well known that high blood pressure is a risk factor for rupture of the aortic aneurysm. Many studies have demonstrated the benefits of physical exercise regarding the lowering impact of blood pressure in a cardiac hypertensive population. At 3 and 6 months of the intervention, the subjects in the exercise group will have: 1) a lowered blood pressure at rest and during exercise, 2) maintenance/ improvement of muscle strength, 3) improvement of aerobic exercise capacity (VO2max), and 4) aortic dilation that remained stable or comparable to the control group. The research objective is to measure and compare to a control group, the effects of an exercise program on the following parameters: blood pressure response at rest and during exercise, as well as the VO2max at 3 and 6 months time of the intervention. This randomised and prospective study will take place at the " Institut Universitaire de Cardiologie et de Pneumologie du Québec (IUCPQ) " and will include patients who have a non-surgical ascendant thoracic aortic aneurysm (ATAA). The selected subjects will be randomised into two groups: 1) exercise group (n=15), and 2) control group (n=15). Both groups will be met prior to the intervention (baseline) and at 3 and 6 months time of the intervention, and measures described below will be recorded.