Sudden Coronary Artery Dissection
June  2016

A 35-year-old female applies for life insurance. Five years prior to the application and one week postpartum, she was diagnosed with a spontaneous dissection of the proximal portion of the left circumflex coronary artery. Medical management was attempted, but because of ongoing severe angina, she underwent coronary artery bypass graft surgery. Angiogram at that time showed no significant atherosclerotic disease.

She has not had any further pregnancies but is considering a future pregnancy. She has had no further chest pains or any other significant cardiac problems. She is followed by cardiology regularly and has had a normal stress test and echo within the last year, both done to evaluate atypical chest pain.

Family history is negative for cardiac conditions. Her medical history is positive for medically controlled hyperlipidemia but is otherwise unremarkable. There is no history of tobacco use, past or present. No imaging studies of other arterial systems were included in the records. Her current ECG is normal.

Traumatic Coronary Artery DissectionWhat are the mortality concerns after a spontaneous dissection of a coronary artery?
Spontaneous dissection of a coronary artery (SCAD) is uncommon and is defined as dissection that is non-traumatic and non-iatrogenic. First reported in 1931, most of the early cases were diagnosed at the time of an autopsy.

This condition has historically been associated with coronary artery disease in young women. With the markedly improved imaging techniques currently used, many feel this condition is more prevalent than previously thought, and might be involved in as many as 24% of myocardial infarctions in women <50 years of age. Some believe the condition is not uncommon in older age men and women as well. And the older the patient, the more likely that the dissection is related to atherosclerosis.

During SCAD separation of the coronary arterial walls results in the creation of a false lumen producing an intramural hematoma which leads to narrowing of the true lumen and decreased coronary blood flow (Figure 2). Severe angina, myocardial infarction or sudden death can occur. SCAD can be associated with underlying atherosclerosis, but it is also found in young individuals with no obvious atherosclerosis. In older men presenting with SCAD, atherosclerosis is not uncommon.

​In-hospital​Varies from 0% - 5%
​One-year​Varies from 1% - 4%
​10-year​Up to 7.7%

Figure 2 – Mortality Concerns with Sudden Coronary Artery Dissection

Although up to 20% of cases are considered idiopathic the remaining 80% are associated with a predisposing arterial disease. Fibromuscular dysplasia (FMD) is the associated disorder in the vast majority of cases, but other associated conditions include postpartum state, multiparity (>four births), connective tissue disorders (e.g. Marfan’s syndrome, Ehlers-Danlos type IV), systemic inflammatory conditions (e.g. systemic lupus erythematosus, Crohn’s disease), extreme emotional stress and hormonal therapy.
It is not uncommon for an affected individual to report a precipitating stressor such as forceful emesis, intense exercise, labor and delivery or recreational drug usage.

Most series have a preponderance of younger women developing SCAD in the peri-partum period. It is known that the hormonal changes of pregnancy cause changes in the vascular wall including smooth muscle proliferation, impaired collagen synthesis and changes to the molecular makeup of the media layer. These changes combined with the increased blood volume and cardiac output may lead to increased shearing forces during the stress of labor and delivery. Underlying arterial disease processes as discussed above may exacerbate these stresses.

The clinical presentation of this condition is typically that of a myocardial infarction. Chest pain, dyspnea, diaphoresis, syncope and nausea are common complaints. The condition can present with cardiac arrest. ST-elevation MI (STEMI) or non-ST elevation MI have both been seen. The most frequently involved artery is the left anterior descending (LAD), but involvement of any of the coronary arteries, including the left main stem, has been documented.

Diagnosis & treatment
The diagnosis of SCAD is most commonly made by coronary angiogram, or at the time of autopsy. Intracoronary imaging with intravascular ultrasound can also be used to make the diagnosis. Diagnosis by cardiac CT angiography (CCTA) has been disappointing thus far, but it has been used successfully for serial monitoring of disease activity.

Treatment consists typically of either conservative management, percutaneous coronary intervention or coronary artery bypass grafting. Thrombolytic therapy is typically not advocated. The natural history of the disorder, based upon follow up angiography, appears to be spontaneous healing in the vast majority of cases.

Long term prognosis is reported as variable. Approximately 80% of the time there is an underlying arterial disorder, most commonly fibromuscular dysplasia, and the underlying condition can create issues with recurrence of coronary artery disease or arterial disease in another location, such as the renal or carotid arteries.

One recent study in Vancouver showed a two-year major adverse cardiac event-rate of 10.4 to 16.9%, with recurrent dissection rate of 13.1%. In another study from the Mayo Clinic, the recurrent dissection rate was 17%.

Regarding mortality, case reports or small series of patients were reported on initially and mortality was high. More recent publications have shown a somewhat improved mortality picture (Figure 3).

​Study​Start Date​Anticipated Completion Date

​The "Virtual" Multicenter SCAD Registry
(supported by Mayo Clinic)

​July 2011​December 2017
​The Canadian SCAD Cohort Study​June 2014​December 2019

Figure 3 –  Current Studies

In one study, involving 87 patients (mean age 42.6 years), the 10-year data suggested there was a 47% chance of subsequent death, congestive heart failure, myocardial infarction or repeat dissection. In other studies, it has been reported that the subgroup of patients with postpartum SCAD have a worse prognosis. They have been reported to have larger infarcts, more proximal artery dissections, and worse post-event ejection fractions.

There is a need for prospective studies to help elucidate the mortality of this condition. Interestingly, there are at least two ongoing prospective studies which might give great information regarding long term prognosis (Figure 3). We will watch these studies carefully and plan on commenting on the results in a future publication.

Returning to the case
This is a case of SCAD in a postpartum woman. Unfortunately, we don’t have information regarding any other underlying etiologies for the SCAD other than the postpartum state.
SCAD in the postpartum period in particular has been reported to have an unfavorable prognosis. The high rate of recurrence after SCAD as well as the association with other vascular problems is problematic. Finally, the high rate of complications, recurrences, and mortality currently being quoted in the literature makes this case appear to have significant long term mortality concerns.

References
https://clinicaltrials.gov/ct2/show/NCT01429727?term=spontaneous+coronary+artery+dissection&rank=1 accessed 2/4/2016.
https://clinicaltrials.gov/ct2/show/NCT02188069 accessed 2/4/2016.
Yip, A, Saw, J “Spontaneous coronary artery dissection—A review”. Cardiovascular Diagnosis and Therapy 2015;5(1): 37-48.
UpToDateR last accessed 2/4/2016.
Pretty, H. “Dissecting aneurysm of coronary artery in a woman aged 42”. BMJ 1931;1:667.
DeMaio SJ Jr. et al. “Clinical course and long-term prognosis of spontaneous coronary artery dissection”. Am J. Cardiol 1989;64-471-474.
Ito, H et al. “Presentation and therapy of spontaneous coronary artery dissection and comparisons of postpartum versus non-postpartum cases”. Am J Cardiol 2011; 107:1590-6.
Tweet MS et al. “Clinical features, management, and prognosis of spontaneous coronary artery dissection”. Circulation 2012; 126:579-88.