Spontaneous Coronary Artery Dissection
Brief Summary of Disease
A topic of recent research is spontaneous coronary artery (SCAD), which is a rare disease that can present itself in many ranging from chronic stable angina to sudden cardiac death. There have been over 300 documented cases of SCAD since the first presentation in 1931. Of those living with SCAD, 90% are women between the ages of 30-60 years old. Further, it accounts for 25% of all heart attacks for women under the age of 60.4 Almost 30% of all cases occur during or after childbirth, with a peak incidence two weeks after delivery.1
Etiology & Pathology
The clinical presentation depends upon how restricted the flow is and the extent of the dissection. During primary coronary dissection, there is separation of the arterial wall layers, thereby creating a false lumen within the layers of the heart. This dissection can occur in the absence of a traumatic event due to a solid swelling of clotted blood within the vessel wall between the heart layers.1,3 The dissection can expand distally if there’s blood accumulation or a clot formation in the false lumen, and may cause the real lumen to compress, leading to myocardial ischemia. This is a disease that occurs when the blood flow to the heart is impaired or reduced due to a partial blockage. This prevents the heart from receiving enough oxygen for optimal function, and if it continues without treatment, it can potentially lead to a heart attack.6
Sympytoms
There is a range of symptoms associated with SCAD, many of which are typical of other heart conditions. These include chest pain and pressure, rapid heartbeat, pain in the extremities, back or neck, excessive sweating, nausea, vomiting, dizziness, extreme exhaustion, and headache.4 One of the main concerns regarding SCAD is that there is no specific, identifiable symptom that distinguishes it from any other disease of the heart. This may be due to lack of research in key symptoms for SCAD, or a lack of reports from patients with different symptoms, due to a poor prognosis during the adverse event.
Diagnosis
In previous studies, all research on SCAD was conducted during autopsies after a sudden cardiac death which limited the prior findings to solely one outcome of SCAD. Recent methods include angiography, intravascular ultrasound (IVUS) and optical coherence tomography (OCT). An angiography is a common diagnostic procedure where a dye is released into the coronary arteries to produce an x ray of the blood vessels. This shows a clear image of the blood flow to the heart and to visualize any problems with the arteries. .4 The newer methods of IVUS and OCT have been used to supplement angiography results and identify more cases of SCAD than previously observed.1-3 Intravascular ultrasound (IVUS) can be used when the angiography does not pick up any results. Usual features for SCAD are a solid swelling of clotted blood in the outer third of the media that compresses the lumen but has little atherosclerosis present. This technique also allows physicians to assess the characteristics of the dissection such as the length and depth, and any intimal tears. Another useful technique is optical coherence tomography (OCT) which uses light-based imaging to produce high-quality images of the coronary artery. This technique is especially useful for identifying intimal tears, and determining the location and length of the accumulated blood clot.1
Vascular changes and coronary atherosclerosis are the most common pathologies associated with SCAD.1 However, a large number of cases are defined as idiopathic; as in no underlying condition can be detected. The most frequently involved vessel is the left anterior descending artery (LAD) which makes up 60% of the affected population, with the remaining cases involving either a multivessel coronary dissection or the left main coronary artery. 1,2
Prognosis
In terms of quality of life, SCAD is linked with many of the common symptoms seen with other cardiac disorders, such as chest pain and nausea.4 All the symptoms related to SCAD can have a negative impact on the quality of life of the individual due to decreased functionality for daily activities and reduced motivational factors. Furthermore, a study was started in 2017 to investigate the prevalence of depression and anxiety in post SCAD patients. The initial review of the data suggested that 33% of SCAD MI survivors had undergone treatment for depression and 37% for anxiety. The current conclusions of the study link a higher risk of depressive and anxiety symptoms in younger individuals post-SCAD, especially in those with peripartum SCAD.5 Also, many SCAD cases seem to have a positive prognosis after the acute phase with recent reports suggesting a 1-5% in-hospital mortality rate for SCAD.3
Children
There are no conclusive findings that link the incidence of SCAD with children. All known cases have been in adults, especially women.
Current Research
Currently, there is a lot of research specifically in potential management methods for SCAD. In
terms of management options for acute SCAD, they are determined based on the blood flow stability and perfusion to the affected vessels. Percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) are the common surgical interventions used in patients with an unstable SCAD condition. PCI for revascularization is usually not recommended unless the blood flow is unstable or there is progression in the dissection. This is because of the high failure rate of 50-60% reported for PCI revascularization in studies over the past 5 years. CABG is another surgical procedure used for SCAD patients, however there is a 70% failure in the short-term period post surgery.8,9 Non-surgical management is usually referred in patients with a stable distal coronary flow since SCAD vessels can heal independent of external intervention.9 Only 3.3% of patients following a conservative, non-surgical model for management of SCAD required unplanned revascularization and extension of the dissection.10
Relevant Resources
Heart and Stroke Foundation
Works Cited:
1. Vrints, C. J. (2010). Spontaneous coronary artery dissection. Heart, 96(10), 801-808. doi:10.1136/hrt.2008.162073
2. Almeda, F. Q., Barkatullah, S., & Kavinsky, C. J. (2004). Spontaneous coronary artery dissection. Clinical Cardiology, 27(7), 377-380. doi:10.1002/clc.4960270702
3. Yip, A., Saw, J. (2015). Spontaneous Coronary Artery Dissection- A Review. Cardiovascular Diagnosis and Therapy, 5(1), 37-48. doi: 10.3978/j.issn.2223-3652.2015.01.08
4. Mayo Clinic. Spontaneous Coronary Artery Dissection (SCAD). (n.d.). Retrieved from http://www.heartandstroke.ca/heart/conditions/spontaneous-coronary-artery dissection
5. Mayo Clinic. Spontaneous Coronary Artery Dissection (SCAD) - Post-SCAD Depression and Anxiety. (2014). Retrieved from https://www.mayo.edu/research/centers-programs/spontaneous-coronary-artery-dissection-scad/projects/post-scad-depression-anxiety
6. Mayo Clinic. Myocardial ischemia. (2018). Retrieved from https://www.mayoclinic.org/diseasesconditions/myocardial-ischemia/symptoms-causes/syc-20375417
7. MLate starters: More Canadian babies born to women over 40 than teens | CBC News. (2016). Retrieved from https://www.cbc.ca/news/canada/manitoba/babies-born-to-over-40-than-under-20-1.3823439
8. Tweet, M. S., Gulati, R., & Hayes, S. N. (2016). Spontaneous Coronary Artery Dissection. Current Cardiology Reports. 18, 6. doi: 10.1007/s11886-016-0737-6.
9. Saw, J., Aymong, E., Sedlak, T., Buller, C. E., Starovoytov, A., Ricci, D., Robinson, S., Vuurmans, T., Gao, M., Humphries, K., & Mancini, J. G. B. (2014). Spontaneous Coronary Artery Dissection Association with Predisposing Arteriopathies and Precipitating Stressors and Cardiovascular Outcomes. Circulation: Cardiovascular Interventions, 7(5), 645-655.
10. Saw, J., Humphries, K., Aymong, E., Sedlak, T., Prakash, R., Starovoytov, A., & Mancini, J. G. B. (2017). Spontaneous Coronary Artery Dissection: Clinical Outcomes and Risk of Recurrence. Journal of the American College of Cardiology, 70(9), 1148-1158. doi: 10.1016/j.jacc.2017.06.053.
11. Prasad, M., Tweet, M. S., Hayes, S. N., Leng, S., Liang, J. J., Eleid, M. F., Gulati, R., & Vrtiska, T. J. (2015). Prevalence of Extracoronary Vascular Abnormalities and Fibromuscular Dysplasia in Patients with Spontaneous Coronary Artery Dissection. The American Journal of Cardiology, 115, 1672-1677. http://doi.org/10.1016/j.amjcard.2015.03.011
Cite This Article:
Ravi R, Chan G., Lewis K., Ho J. Spontaneous Coronary Artery Dissection
. Illustrated by Montakhaby S. Rare Disease Review. January 2020.
DOI:10.13140/RG.2.2.10020.83840.
