Coronary artery dissection

Spontaneous coronary artery dissection (SCAD) is rare and occurs in relatively young persons, and represents 0.7-1.1% of patients undergoing angiography.

Spontaneous coronary artery dissection ((SCAD)is an important cause of myocardial infarction in young patients.

Accounts for less than 1% of all acute myocardial infarctions.

A non–atherosclerotic disease of the coronary arteries and patients usually present with an acute coronary syndrome.

0.2-1.1% of patients undergoing angiography for acute coronary syndrome have a spontaneous coronary artery dissection.

Cohort studies indicate that one quarter to one third of myocardial infarctions in women younger than 50 years of age are caused by SCAD.

SCAD accounts for approximately 15-20% of myocardial infarctions during pregnancy or the peripartum.

More recent studies have demonstrated 1-4% of patients with acute coronary syndrome may have spontaneous coronary artery dissection.

May be responsible for one third of the acute coronary syndromes in females younger than 50 years of age.

Is the most common cause of peripartum myocardial infarction.

Estimated 800 new cases of spontaneous coronary artery dissection occur annually in the US.

Rare cause of myocardial infarction.

Approximately 2:1 female predominance.

SCAD occurs primarily in women, and the presence of cardiovascular risk factors among women with myocardial infarction from SCAD is lower than the prevalence of risk factors among women with myocardial infarction from atherosclerosis.

Strong predilection for otherwise healthy women.

Requires a accurate and rapid diagnosis because management of acute  myocardial infarction  caused by SCAD differs from that of atherosclerotic induced myocardial infarction.
A finding of SCAD may indicate an underlying systemic arterioscleropathy-fibromuscular dysplasia.

Additional  arteriopathies associated with SCAD include: Marfan syndrome, Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, alpha-1 antitrypsin deficiency, and polycystic kidney disease.

70-82% who suffer a spontaneous coronary artery dissection are women.

Mean age is 40-43 years.

Most patients aged 35-40 years.

Among women younger than 50 years who present with acute coronary syndrome the prevalence of spontaneous coronary artery dissection is 9%.

The percentage of postmenopausal women in SCAD registries is consistently about 55% and the prevalence of nulliparity and multi parity or similar  in patients  with SCAD.
Peripartum  SCAD counts for a few than 15% of all cases.

Approximately 1/3 of cases occurs in the peripartum period.

Has been reported during menses.

May result in myocardial infarction, angina and sudden death.

May be responsible for as many as one of 10 episodes of acute coronary syndrome in women younger than age of 50 years.

Unknown cause.

Low estrogen levels may be associated.

It is defined as a separation of the layers of the epicardial coronary artery wall by intramural hemorrhage, and it may be associated with or without an intimal tear.

Optical coherence tomography suggests the primary event may be a medial dissection rupture of the vasa vasorum resulting in secondary intramural hemorrhage and formation of a intramural hematoma.

Subsequently coronary obstruction with development of acute myocardial infarction occurs due to luminal compression, either by dissection flap or by propagation of and intramural hematoma.

Associated with connective tissue disorders, coronary artery spasm, strenuous exercise, peripartum/postpartum status, emotional distress, use of oral contraceptives, and menstruation.

Fibromuscular dysplasia it has been identified as an independent predictor, and there’s less common in men.

Mortality rate 75%.

Most cases diagnosed postmortem.

Has a familiar association.

Refers to an atraumatic non iatrogenic separation of coronary artery layers by hemorrhage that leads to the formation of a intramural hematoma.

Proposed mechanisms include initiation of dissection and hemorrhage by an intimal tear and creation of a false lumen or a rupture of the vasa vasorum leading to intramural hemorrhage and medial dissection without intimal tearing.

Involves the development of the dissection plane within the coronary artery wall along with a concurrent intramural hematoma.

The dissection ultimately obstructs bloodflow and causes myocardial ischemia and infarction.

Occurs most commonly young women with no with minimal cardiovascular risk factors.

Associated with extreme exercise, emotion, connective tissue disorders, and fibromuscular dysplasia.

It’s cause is unknown but probably includes factors related to patient vulnerabilities and inciting triggers such as: emotional distress, physical stress, the use of stimulating medications or illicit drugs, and hormonal triggers,.such as pregnancy.
Case reports revealing association between SCAD and inflammatory disorder such as SLE, sarcoidosis, inflammatory bowel disease, and celiac disease, however the prevalence of systemic inflammatory disorder is among patients with a CAD is less than 5%.

Autopsies show focal infiltration of inflammatory cells, predominately eosinophils, but absence of such changes in the intimate and media.

Formation of an intramural hematoma has potential to compress the true vascular lumen causing myocardial ischemia and or infarction.

LAD involved in 78% of cases, with 24% involving left main artery and 40% with multivessel dissection.

Patients who survive have greater than 82% long-term survival.

Management is as for other acute coronary syndromes.

Presenting symptomatology ranges from the chest pain to acute coronary syndrome, ventricular fibrillation and sudden-death.

Management is not well defined and is dependent on clinical presentation, extent of dissection and amount of myocardium at risk.

Medical therapy can be instituted in stable patients with middle or distal local dissection if the diameter of the lumen is not limited by more than 50% and coronary artery bloodflow is adequate.

Medical treatment includes the use of anti-thrombotic’s, such as aspirin, thienopyridines, or heparin with bridge to warfarin, beta blockers, and nitrates.

Medical therapy can lead to resolution of dissection.

Thrombolytic therapy is felt to be too hazardous to be used as it is associated with significant complications.

Revascularization procedure is considered for patients will continue chest pain, ischemia, ST elevation, or hemodynamic instability.

Percutaneous intervention may be utilized in limited circumstances, particularly when a single vessel is involved, but surgery is the major revascularization procedure.

Surgical revascularization is the method of choice when dissection is extensive such as when the left main artery, proximal left anterior descending artery, multiple vessels or complex vessel involvement is present.

Because of technical failures the rate of percutaneous revascularization is only about 65%.

Hospital mortality rate for initial conservative management is reported to be 0-4%, and 1 and 10 year mortality rates are 1.1 and 7.7%, respectively.

The ten-year incidence of major adverse cardiaovascular events, including death, recurrent dissections, heart failure, myocardial infarction after an initial event is as high as 47%.

A vascular medicine evaluation is recommended for all patients diagnosed with SCAD.

Patients with a family history or physical examination findings suggestive of known arteriopathies may benefit from a genetics evaluation. 

Coronary computed tomography angiography is preferred for imaging when possible, as it has higher spatial resolution than magnetic resonance angiography or ultrasonography. 

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