Discussion
The basic pathophysiology behind post traumatic AR can be either acute rupture of the thoracic aorta at the isthmus where the mobile thoracic aorta joins the firmly fixed aortic arch 13,14, leaflet injury 3-12 or avulsion of the commisures15. The mechanism behind such injuries involves increased pressure inside the aortic root with a closed aortic valve and low left ventricular pressure in diastole, leading to high transvalvular gradient. The left coronary sinus being a more posterior structure is less commonly involved in such trauma6. Since the left and right coronary sinuses have the origin of coronary arteries, they are pressure release areas; thus, the non-adjacent sinus bears the major brunt and a tear of the NAL is commonest pathology5.
Patient presenting late with AR after blunt trauma to chest5,8 have been described in literature, but they are mostly upto few months. Patients presenting late mostly have a tear in one of the leaflets which is small and insignificant to start with and gradually progresses with time. In these patients the collagen in the spongiosa is gradually replaced by mucopolysaccharides leading to myxomatous degeneration and progressive weakness of the leaflet, causing further damage16. Our case is unique because a patient remaining asymptomatic for 2 years after trauma and incidentally being diagnosed with severe AR has not been reported.
Management of patients presenting late with severe asymptomatic AR is always a matter of debate and traditionally onset of ventricular dysfunction, acute pulmonary edema, and a systemic diastolic blood pressure of less than 50 mm Hg are indications for immediate surgery.17 Waiting for symptoms or ventricular dysfunction might lead to some irreversible ventricular damage not correctable by surgery10; thus early surgery in asymptomatic patients might be a pragmatic option6 as done in our patient. Another point regarding surgery requires a special mention. Traditionally valve replacement was the standard approach in such patients, but multiple repair techniques are now being explored in patients with limited damage to a single leaflet18. However, the assessment of the valve leaflets preoperatively by imaging or intra-operatively by hand and eye assessment are imperfect as there is a report of microscopic degeneration in an otherwise healthy-looking leaflet, which could progress with time19.Thus, valve replacement is the standard approach in these cases.