In the hectic environment of the emergency department, rapid diagnosis and emergent management of life-threatening conditions must occur. In the patient with acute chest pain and an EKG concerning for an ST segment elevation myocardial infarction STEMI, the diagnosis and treatment is generally straightforward. National guidelines recommend emergent reperfusion with percutaneous coronary intervention (PCI) or fibrinolytic therapy. Unfortunately, the potential for patient harm is high when acute aortic dissection causes an acute coronary syndrome and produces ischemic EKG changes.
Aortic dissection (AD) occurs when an injury to the innermost layer of the aorta allows blood to flow between the layers of the aortic wall, forcing the layers apart. In most cases, this is associated with a sudden onset of severe chest or back pain, often described as “tearing” in character.
Treatment of AD depends on the part of the aorta involved. Dissections that involve the first part of the aorta usually require surgery. Surgery may be done either by an opening in the chest or from inside the blood vessel. Dissections that involve the second part of the aorta can typically be treated with medications that lower blood pressure and heart rate, unless there are complications.
Without treatment, about half of people with Stanford type A dissections die within three days and about 10% of people with Stanford type B dissections die within one month.
Because an aortic dissection can be missed in the setting of acute coronary syndrome, doctors must make sure to look out for unique signs and symptoms indicative of AD. Practitioners must keep in mind that because the right coronary artery is the most common vessel affected by pathologic mechanisms of AD, an inferior STEMI is the most common ACS presentation in patients with aortic dissection.
Approximately 70% of patients with acute aortic dissection will have an EKG abnormality. These can include non-specific ST segment or T-wave changes, left ventricular hypertrophy, and atrial dysrhythmias.
Medical providers must consider the diagnosis of aortic dissection, especially in patients with an inferior STEMI. Additional history and physical examination findings may prevent catastrophic results from antiplatelet, anticoagulant, or fibrinolytic therapy. Importantly, an anterior STEMI is rarely, if ever, associated with an acute aortic dissection.
How should the medical clinician approach the patient with acute chest pain, ischemic EKG findings, and risk factors for an acute aortic dissection? A presentation in which acute aortic dissection is suggested and an inferior or posterior STEMI is noted on EKG should prompt rapid evaluation of the thoracic aorta.
Fibrinolytic therapy should be withheld until aortic dissection can be excluded. Confirmation or exclusion of aortic dissection can be rapidly accomplished with computed tomography of the chest and abdomen. Emergent PCI can also establish the diagnosis in select cases. When the clinical presentation is concerning for an acute aortic dissection and non-diagnostic EKG abnormalities are seen, a similar therapeutic approach is warranted.
It may be medical malpractice if a doctor fails to respond to telltale signs of an aortic dissection and the patient, as a consequence, is injured or dies.
- Up to 70% of patients with acute aortic dissection will have an EKG abnormality.
- Up to 8% of type A dissection’s can be complicated by STEMI.
- The right coronary artery is the most common artery involved in cases of aortic dissection.
- An anterior STEMI is rarely associated with an acute aortic dissection.
- Medical practitioners should not administer fibrinolytic therapy to STEMI patients in whom there is a suspicion of an acute aortic dissection.