Aortic dissection, chest pain

Dissection of the aorta has been reported during cocaine use (82,83). The authors of these two reports noted that all six cases of this rare complication reported in the past 5 years were in men with pre-existing essential hypertension. In a review of emergency visits to a hospital during a 20-year period, 14 of 38 cases of acute aortic dissection involved cocaine use 6 were of type A and 8 of type B (84). Crack cocaine had been smoked in 13 cases and powder cocaine had been snorted in one case. The mean time of onset of chest pain was 12 hours after cocaine use. The chronicity of cocaine use was not known in most of the cases. The cocaine users were typically younger than the non-cocaine users. Chronic untreated hypertension and cigarette smoking were often present. 

Chest pain may be indicative of a recent myocardial infarction with complicating stroke, aortic dissection (particularly if the pain is also interscapular) or pulmonary embolism and raises the possibility of paradoxical embolism. 

A healthy 39-year-old man developed retrosternal chest pain radiating to the back with nausea and sweating. About 10-15 minutes before, he had inhaled cocaine for 2 hours and then smoked crack cocaine. He had an aortic dissection, which was repaired surgically. 

Type 1 aortic dissection is one of the most difficult vascular lesions to manage in the presence of major stroke. The patient may present with chest pain and asymmetric pulses. Stroke may occur in the distribution of any major cerebral arteries because the dissection can involve both carotid and vertebral origins [28], Since rupture into the chest or extension of dissection into the pericardium or coronary origins is fatal, thrombolysis or anticoagulation cannot be used. 

Pulsation of the aorta causes artifacts, especially in the aortic root and ascending aorta. ECG-triggered data acquisition helps to significantly reduce these artifacts and therefore plays an important role in the examination of unclear chest pain or thoracic aortic dissection (Fig. 23.1). Furthermore, this technique enables the evaluation of coronary arteries and can replace invasive clinical diagnostics in some cases. Flowever, detailed protocols of the thoracic aorta are normally based on protocols of coronary artery CT. Due to their specifications, they lead to longer acquisition times than those of standard protocols and do not properly visualize the abdominal aorta. This can be overcome by an ECG-gated acquisition of the thoracic aorta and a change to the standard protocol for the abdominal aorta. In order to achieve a sufficient contrast in the abdominal aorta, the time delay to modify the examination protocol should be minimized (Fig. 23.2). 

Aortic arch dissection can cause profound hypotension, with global, and sometimes boundary zone, cerebral ischemia or focal cerebral ischemia if the dissection spreads up one of the neck arteries. Clues to this diagnosis are anterior chest or interscapular pain, along with diminished, unequal or absent arterial pulses in the arms or neck and a normal electrocardiogram, unlike acute myocardial infarction, acute aortic regurgitation and pericardial effusion. 

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