An uncommon presentation of acute type A aortic dissection

To the Editor The case report of ‘An uncommon presentation of acute type A aortic dissection: left main coronary artery obstruction’ by Courand et al.,1 published in the January 2012 issue of this Journal, reminds us of the need to maintain a high suspicion rate when observing patients with chest pain and initially atypical ECG manifestations. In a patient with prolonged chest pain, nondiagnostic findings in a first ECG were quickly followed by the appearance of diffused marked ST segment depression, during recurrence of retrosternal pain and worsening of physical status. The authors considered a diagnosis of non-ST segment elevation myocardial infarction (NSTEMI), but the picture was later identified as due to Stanford type A aortic dissection with obstruction of the left main coronary artery. The authors suggest that in patients with an ECG pattern of NSTEMI aortic imaging should be considered, whereas in patients with ST segment elevation myocardial infarction (STEMI) further evaluation is required in selected cases with suggestive symptoms or risk factors2 of aortic dissection. Anyway, it must be remembered that ‘typical’ symptoms, like tearing pain, are infrequent in aortic dissection, where the prevailing complaint is a dull, pressure-like chest pain, sometimes radiating to the back; neurological symptoms that could help in the differential diagnosis are present only in a minority of cases;3 as also reported in the study by Courand et al. and in a recent study by Patruno et al.,4 differential pulses are an infrequent sign. Even though more uncommon than NSTEMI, a STEMI pattern also is not infrequent in Stanford type A aortic dissection.5–11 More than 30 years ago, in the prethrombolytic/preangioplasty era, our group described a case of acute aortic dissection,12 characterized by a nondiagnostic initial ECG (Fig. 1), sequentially followed by ST segment elevation (Fig. 2) and ST segment depression (Fig. 3), rather similar to the ECG presented by Courand et al. in the antero-lateral leads, in an overall time of 40 min.Fig. 1: No captions available.Fig. 2: No captions available.Fig. 3: No captions available.In patients with acute chest pain, thorough ECG monitoring is advisable, as a ‘dynamic pattern’ of the ST abnormalities (especially rapid changes between ST elevation and ST depression)13 could raise a strong suspicion of intermittent coronary occlusion, as described in coronary dissection.14 Taking care not to delay potentially needed reperfusion strategies, in such selected cases, a transthoracic echocardiogram15 should be obtained as soon as possible, before performing coronary angiography or – even worse – administering antithrombotic therapy.16–21 If the suspicion becomes well founded, a multimodality imaging approach [transesophageal echocardiography, computed tomography (CT) scan] could help in validating the diagnosis.10,22–24