"My Chest is Hurting Really Bad"

Adrian Crisan, MD and Chat Dang,MD

July 01, 2003

This ultrasound represents aortic dissection. As noted in figure A, the presence of the intimal flap helps to distinguish between the false and the true lumen. Figure B shows the color Doppler image obtained in the same area illustrating blood flow consistent with the identification of a vascular structure.

The patient?s blood pressure started to rise and it was managed with labetalol. IV. Morphine sulphate was used to control her chest pain. The vascular surgery team assumed further care, and the patient was taken to the OR. The patient decompensated during surgery, and succumbed prior to the correction of her aortic defect.

Aortic dissection is a true hypertensive emergency and should be promptly identified. Males are usually affected more commonly than females and the majority of the patients are between 50 and 70 years of age. A history of hypertension is the most common risk factor and it is present in up to 90% of the affected patients. The dissection starts at a point of intimal weakening that allows blood to leak into the media and cleave it from the adventitia. A weak media, as seen with Marfan?s syndrome, is also a predisposing factor. The most important factor in propagating the dissection is the rate of rise in the blood pressure (dP/dT). Traditionally, aortic dissections are classified according to the dissection site. The two major classification systems are Debakey and Stanford.

Dissections involving the proximal aorta are more common. Pain is the most common presenting symptom and it is usually described as acute, excruciating and tearing or ripping in quality. Patients may also present with acute CVA, AMI, paraplegia, syncope, and flank pain depending on which aortic area is involved.

Clinically, unequal or absent radial or femoral pulses are the hallmark of aortic dissection. Unequal blood pressure readings, focal neurological deficits, shock like appearance despite elevated blood pressure or a murmur of aortic regurgitation are all possible findings encountered in this setting.

The diagnosis of aortic dissection may be suspected if the CXR demonstrates mediastinal widening. Despite the fact that this is the most common radiologic abnormality in this setting, it has a relatively low specificity. A widened mediastinum is more frequently seen with traumatic rupture of the aorta than with aortic dissection, because the split of the media may not result in a ballooning out of the aorta. EKG?s are most useful in ruling out associated AMI?s. Definitive studies include transthoracic or transesophageal echocardiography, aortography, MRI, or dynamic CT with contrast. In the acute setting, echocardiography is the best choice with a sensitivity and specificity approaching 100% in experienced hands.

Acutely, treatment is aimed at controlling the rate of rise in the blood pressure. This can be accomplished with a combination of a B-blocker and nitroprusside or labetalol as single agent. Pain is managed with IV narcotics. Proximal dissections are treated surgically while distal ones may be managed medically. Consultants should be involved early in the management of these patients.

Pearls:

• A widened Mediastinum is more frequently seen in traumatic rupture of the aorta than aortic dissection.
• Hypotension may be present in patients with proximal aortic dissection and tamponade.
• In suspected aortic dissection, echocardiography is the best choice with a sensitivity and specificity approaching 100%

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