Association of Left Ventricular Hypertrophy and Aortic Dilation in Patients with Acute Thoracic Aortic Dissection

This study was designed to evaluate the impact of left ventricular mass on aortic diameters in patients who presented with acute thoracic aortic dissection where aortic dilation is common. Retrospective review of transthoracic and transesophageal echocardiograms was conducted for 63 patients treated for acute thoracic aortic dissection and for 16 normal subjects who were comparable for gender prevalence, age, heart rate, and blood pressure. The diameter of the aortic root was measured by transthoracic echocardiography. Diameters of the ascending aorta, and of the aorta at locations of 25, 30, and 35 cm from the dental arch were measured by transesophageal echocardiography. The findings indicated that all aortic diameters were significantly larger in patients with aortic dissection. Patients with aortic dissection also presented with greater left ventricular mass indices (p<0.00001) than normal subjects. Fractional shortening and left atrial diameter measurements obtained in patients with aortic dissection were similar to those obtained in the control group. Overall, the left ventricular mass index exhibited univariate relationships with aortic root diameter (r=0.27, p<0.02) and aortic diameters at 25 cm (r=0.51, p<0.00001), 30 cm (r=0.58, p<0.00001), and 35 cm (r=0.55, p<0.00001) distal to the arch but not with the diameter of the ascending aorta. After adjusting for gender, body mass index, history of hypertension and aortic dissection extent (Stanford types) by separate multivariate models, the authors found that the left ventricular mass index was independently associated with aortic diameters at 25 cm (beta=0.32, p<0.001), 30 cm (beta=0.38, p<0.0001), and 35 cm (beta=0.34, p < 0.0005) distal to the arch. They conclude that left ventricular mass is independently associated with aortic arch and descending aorta diameters in patients with acute thoracic aortic dissection. Left ventricular hypertrophy may be considered a risk factor for aortic enlargement and subsequent dissection.