Spontaneous Coronary Artery Dissection (SCAD)

• Spontaneous coronary artery dissection (SCAD) refers to an intimal tear (or less commonly vasa vasorum haemorrhage) leading to creation of a false lumen in the arterial wall in the absence of a clear mechanical cause (eg, trauma or catheter manipulation). (Source)
  • Compression of vessel lumen → ischemia in subtended myocardial territory
• Associated conditions: fibromuscular dysplasia, peripartum status, and episodes of extreme emotion or exercise
  • Thus, hormonal disruption hypothesized to be more common in women with SCAD (compared with general population)
• Fewer than 5% of all ACS is caused by SCAD, but proportions are higher in certain populations, such as women who are pregnant or post-partum
• Heightened awareness, improved diagnostic accuracy increasingly important for clinicians to understand SCAD
• Important because short- and long- term management strategies differ from typical strategies for atherosclerotic disease
• SCAD may be a cause of up to 1% to 4% of ACS cases overall, may be the cause of ACS in up to 35% of MIs in women ≤50 years of age
• The most common cause of pregnancy-associated MI (43%)
• SCAD has been reported in all major racial and ethnic groups
• Majority of patients are white
  • May reflect referral and sampling bias, demography of patients cared for at reporting centers
• Coronary Distribution
  • Left anterior descending artery is the most commonly affected (32%-46% of cases)
  • In the majority of cases, mid to distal segments of coronary arteries are affected; in only <10% of cases are the proximal left anterior descending or circumflex, right coronary, or left main arteries affected
  • Multivessel SCAD occurs in 9% to 23% of cases

Management

• Inpatient Treatment
  • Preserved coronary blood flow (TIMI 2-3) and hemodynamically stable: conservative therapy with inpatient monitoring (3-5 days)
  • Poor coronary blood flow (TIMI 0-1) and/or hemodynamically unstable: revascularization with percutaneous coronary intervention (POBA/STAR technique preferred) or coronary artery bypass grafting
• Outpatient Treatment
  • 🌟 Cardiac rehabilitation referral
  • Imaging for vascular abnormalities, including FMD
  • BBs
  • ASA/DAPT(?)
    • “I think the jury is still out regarding antiplatelet therapy,” says Tweet. “If a patient has a stent, I’ll prescribe dual antiplatelet therapy for that first year after the heart attack; otherwise, there’s often no reason for them to be on two agents, and I typically keep them on aspirin alone. We need more evidence to know what is best for SCAD patients in the short- and long-term, however.” (Source)
  • BP control
  • Avoid anticoagulation
    • “theoretical risk; if there’s an intramural hematoma, it could bleed more and cause further obstruction or extend the dissection. Moreover, these lesions are not typically associated with significant thrombus.” (Source)
  • Medical genetics evaluation, if applicable (eg if FMD, aortopathy, Marfan diagnosed at time of SCAD presentation)
  • Mental health assessment and care
    • Nearly one in three survivors of SCAD may experience clinically significant PTSD symptoms years after their event, along with high rates of comorbid anxiety and depression.¹
  • Avoidance of pregnancy
  • Limitation of exogenous hormones
• Pregnancy after SCAD? (See Pregnancy after SCAD?)
  • In follow-up, 6 out of 7 patients in the iSCAD registry did not have SCAD-related complications; 1 patient had recurrent SCAD at 9 weeks postpartum resulting in an ST-elevation MI involving the left main coronary artery, treated with emergent coronary artery bypass surgery
• Return to exercise after SCAD
  • Physical Activity and Exercise in Patients With Spontaneous Coronary Artery Dissection and Fibromuscular Dysplasia. Eur Heart J2021;42:3825-3828.
  • 

Sex Hormones and SCAD

• Complicating the hormonal hypothesis, several large cohort studies demonstrated that SCAD can affect women who are nulliparous, pregnant, postpartum, multiparous, and post-menopausal
• Conclusive evidence regarding use of exogenous hormones, the risk of SCAD or its recurrence is lacking
• Rates of contraceptive and postmenopausal hormone use in women with SCAD are not substantially different from the use in the general population
• If hormones do play a role, unknown whether it is the absolute levels and/or fluctuations in circulating estrogen and progesterone that affect the process
• Temporally, SCAD has been reported to occur just before or during menstruation while taking hormonal contraceptives and postmenopausal hormone therapy and in women with a history of infertility and/or prior or current treatment for infertility

Pregnancy-associated SCAD

TODO

Pregnancy after SCAD?

• Women are often advised to avoid pregnancy after SCAD, so there are few reports of maternal or fetal outcomes in these patients.
• In one series, 1 of 8 patients (13%) experienced recurrent SCAD 9 weeks postpartum requiring emergency CABG
• In another, 2 of 11 (18%) women had recurrent MI postpartum
• These data suggest that the majority of SCAD patients who subsequently conceive experience uncomplicated pregnancies
• However, SCAD is unpredictable
  • Cardiovascular testing and monitoring cannot prevent or assess risk for recurrent SCAD
• A reasonable approach to those with a strong desire to become parents:
  • Minimize risks for unplanned pregnancy
  • Provide thorough pre-conception counseling
• Reviewing available data on pregnancy outcomes and focusing on individual maternal/fetal risks such as left ventricular function, residual cardiac symptoms, and teratogenic drug use
• Due to the hormonal stimulation protocols required, there are potential and unknown risks of in vitro fertilization, whether or not a gestational carrier is used.
  • “Natural cycle” (unstimulated) in vitro fertilization with a gestational carrier may be safer
  • A surrogate pregnancy with donor oocyte would mitigate/preclude maternal risks
• If, after comprehensive cardiovascular evaluation and medication review, patients elect to proceed with conception or a woman becomes pregnant due to contraceptive failure, management should be coordinated by a multidisciplinary cardiology, maternal-fetal medicine, and anesthesiology team.
• Safety of pregnancy termination after SCAD is unknown, and similarly requires coordination by the multidisciplinary team.
• Special considerations beyond routine prenatal care
  • Early ultrasound (7-8 weeks) to determine fetal viability, fetal number, and define gestational age
  • Cardiac evaluation and maternal echocardiography: 8-12, 22-24, and 32-34 weeks gestation
  • Anesthesiology consultation at 32-34 weeks
  • Multidisciplinary team review at 34-36 weeks to determine location, timing, and method of delivery
  • Discontinue clopidogrel at 36 weeks to permit option of intrapartum neuraxial anesthesia
• Delivery and early post-partum care
  • Delivery should occur at a level 3 or 4 perinatal center due to expedient subspecialty resource availability
  • Scheduled delivery at 39-40 weeks gestation, optimally when providers familiar with individual patient care are collectively available. In the event of planned labor induction, specific intrapartum parameters include:
    • Early neuraxial anesthesia placement to reduce the catecholamine-mediated tachycardia associated with labor
    • Avoidance of terbutaline (as a uterine relaxant) due to reflex tachycardia potentially increasing myometrial oxygen demand
    • Consider delayed Valsalva maneuvers/passive descent (“delayed pushing”) in the second stage of labor to optimize maternal venous return, with operative vaginal delivery reserved for standard obstetrical indications
    • In the event of postpartum hemorrhage, avoidance of methylergonovine due to risk of coronary arterial spasm
  • Per maternal preference, immediate postpartum bilateral tubal ligation may be considered
  • If antepartum and intrapartum courses are uncomplicated, patients may be transferred to the routine, postpartum ward with plan for expeditious evaluation of any cardiopulmonary symptoms
• Contraception
  • Paucity of evidence to guide recommendations regarding specific contraceptive methods, but risks associated with pregnancy exceed those of any form of contraception.
  • In women who have completed their families, permanent sterilization of the patient (assuming medical candidacy) or partner often represents best option.
  • Highly effective forms of contraception are recommended, preferably avoiding estrogen-containing options as these may mimic a hormonal milieu similar to pregnancy.
  • Long-acting progesterone-only methods (subdermal levonorgestrel implant) and levonorgestrel-releasing IUD appear safe in women with cardiovascular disease and have very low (<1%) annual failure rate
    • Safety profile of these methods has not been assessed after SCAD
    • The levonorgestrel IUD has the advantage of reducing menstrual blood loss, a particular issue for reproductive-age women on DAPT
    • Nonhormonal copper IUD remains an option, often is associated with increased menstrual bleeding and slightly higher rates of unintended pregnancy
    • All barrier or periodic abstinence methods, even when used consistently, have relatively high failure rates
    • If these are strongly preferred by couples, addition of spermicide to barrier method may reduce rates of unintended pregnancy
    • Safety of emergency contraception in the post-SCAD population unknown
• Menorrhagia associated with antiplatelet therapy or anticoagulation
  • Menorrhagia relatively frequent side-effect of DAPT
  • The levonorgestrel-releasing IUD simultaneously fulfills purposes of both contraception and reduction in uterine bleeding
  • If exogenous hormones used, progesterone-only agents are a potentially better option than regimens containing estrogen
    • May be accompanied by unpredictable menstrual bleeding patterns
  • When preserving fertility is not a goal, endometrial ablation, which can be performed safely in women who require DAPT or anticoagulation, is an attractive option

Menopausal Management of SCAD

• Concerns include uncertain effects hormone therapy (HT) on SCAD incidence and recurrence and the absence of safety data available to guide the initiation or continuation of HT specific to SCAD
• Key to individualize recommendations through use of relevant consensus statements, guidelines, indications for
  • Account patient preferences, known/perceived risks and benefits, symptom severity
  • Recognizing risks of HT differ depending on type, dose, duration of use, route of administration, timing of initiation, and whether a progesterone is used
• Patients who experience SCAD while receiving HT should have their indications for HT reassessed, and unless there are compelling reasons to continue, HT should be discontinued
• Indications for initiation of exogenous HT include premature and early surgical menopause, severe vasomotor symptoms that cannot be managed with lifestyle or nonhormonal treatments, and local treatment of genitourinary syndrome of menopause
• If severe vasomotor symptoms/genitourinary syndrome of menopause develop at menopause or return on stopping HT, consideration of the use of HT can be made
  • Collaboration with cardiovascular, menopause specialists
• Goal: lowest, effective dose of systemic HT consistent with treatment goals that provides benefits and minimizes risks
• Locally applied vaginal estrogen is thought to be safe because there is minimal systemic absorption
• Patients with cardiovascular disease are typically advised to use a transdermal systemic agent to minimize activation of thrombotic factors and effects on lipids
• Indications, benefits, and risks of continuing or discontinuing use of HT should be reviewed periodically

Angiographic Classifications

• Type 1 SCAD depicts contrast dye staining of arterial wall with multiple radiolucent lumen, with or without dye hang-up or slow contrast clearing from the lumen.
• Type 2 SCAD depicts diffuse and smooth narrowing that varies in severity
  • Type 2A describes the presence of normal arterial segments proximal and distal to dissection
  • Type 2B describes dissection that extends to distal tip of the artery.
• Type 3 SCAD depicts focal or tubular stenosis that appears similar to atherosclerosis.

Resources

• 📄 Lewey J, El Hajj SC, Hayes SN. Spontaneous coronary artery dissection: new insights into this not-so-rare condition. Annu Rev Med. 2022;73(1):339-354. doi:10.1146/annurev-med-052819-023826
• 📄 Tweet MS, Gulati R, Hayes SN. What clinicians should know αbout spontaneous coronary artery dissection. Mayo Clinic Proceedings. 2015;90(8):1125-1130. doi:10.1016/j.mayocp.2015.05.010

Footnotes

1. Sumner JA, Kim ESH, Wood MJ, et al. Posttraumatic stress disorder after spontaneous coronary artery dissection: a report of the International Spontaneous Coronary Artery Dissection Registry. J Am Heart Assoc 2024;13:e032819. ↩