Echocardiographic delineation of type A aortic dissection

Introduction: In addition to proving the visualisation data, studies on the intimal flaps of aortic dissection based on echocardiography have been very limited. Methods: Twenty-seven patients undergoing an operation of type A aortic dissection with preoperative transthoracic and/or intraoperative transesophageal echocardiography archived in the Horizon Cardiology Web of the hospital available for review and measurement were selected into this retrospective study. By way of quantitative and qualitative approaches, flap movement, dissection extent and aortic obstruction were sufficiently evaluated. Results: An intimal flap was visualised in 22 (81.5%) patients and linear artifact was viewed in 1 (3.7%), and in the remaining 4 (14.8%), neither an intimal flap nor a linear artifact was visible. Dissection extents were 2.78 +/- 1.53 cm and 2.03 +/- 1.19 cm in the horizontal and vertical direction, respectively. Sub- or semi-circumferential dissection was noted in 14 (51.8%) patients. No total circumferential dissection was found in this patient population with type A aortic dissection. The obstruction of the aortic valve orifice or aortic cavity developed in 11 (40.7%) patients. Flow disturbance and thrombus in the false lumen were visualised in 24 (88.9%) and 4 (14.8%) patients, respectively. The breadth of flap movement in short-axis plane was much larger in the Aortic Obstruction Group than that of the Non-Obstruction Group (1.55 +/- 1.14 cm vs. 0.75 +/- 0.526 cm, p <0.05). Conclusions: Preoperative transthoracic or transesophageal echocardiographic evaluations offer a convenient and precise diagnostic tool for aortic dissection. The dissection extent may directly correlate and substantially reflect the clinical symptoms of the patients with type A aortic dissection in response to the haemodynamic impairment. Preoperative echocardiographic delineation would assure adequate means and extent of the impending operation. (Hong Kong j.emerg.med. 2012;19:32-40)