The Presenting Chest Roentgenogram in Acute Type A Aortic Dissection: A Multidisciplinary Study

Acute type A aortic dissection requires early diagnosis and prompt surgical intervention. It is not entirely clear whether patients with this form of dissection have clear-cut chest roentgenogram (CXR) patterns or whether the CXR can guide the physician in directing further workup for acute aortic dissection. The purpose of this study is to evaluate the impact of the initial CXR in arousing suspicion for acute type A aortic dissection. Twelve physicians from four specialties (emergency medicine, radiology, cardiology, and cardiothoracic surgery) evaluated the presenting CXR of ten patients with acute type A aortic dissection and the CXRs of ten normal individuals in a blinded manner. They were asked whether the CXRs were normal or abnormal (part A) and what the findings were and then were asked whether the CXRs were suspicious for acute aortic dissection (part B) and what the findings were. In part A, of the normal CXRs 81 of 120 (68%) readings were recorded as normal. Of the dissection CXRs 112 of 120 (93%) readings were recorded as abnormal (P < 0.001). In part B, the physicians were asked specifically about suspicion for aortic dissection. Of the normal CXRs 101 of 120 (84%) readings were listed as not suspicious for dissection (i.e., 16% of the normal CXRs were listed as supsicious for dissection). Of the dissection CXRs 88 of 120 (73%) readings were recorded as suspicious for dissection (p < 0.001). The most frequent findings on a dissection CXR when physicians were specifically asked about dissection included widened mediastinum in 46 of 120 (38%) followed by not suspicious for dissection in 32 of 120 (27%). Among the physician specialties the only statistically significant finding was that the cardiology group was the most likely group to find an abnormality in a "normal" CXR. This data indicates that the presenting CXR is neither sensitive nor specific for acute type A dissection. In a patient with a suspicious history or physical examination, however, a CXR showing mediastinal widening or other aortic abnormalities should increase the suspicion for dissection and warrant further workup. Furthermore in a patient with a clinical suspicion a normal CXR reading should not delay echocardiography to rule out type A dissection.