Spontaneous coronary artery dissection (SCAD)

Article written and reviewed by Dr Luca Moretti

Spontaneous coronary artery dissection, abbreviated SCAD, is an acute separation of the layers of a coronary artery wall that does not result from trauma, instrumentation, or atherosclerosis as the primary process. Blood within the wall creates a false lumen or hematoma and compresses the perfused channel; compression of the true lumen reduces myocardial flow. The typical manifestation is an acute coronary syndrome, often an infarction.
The definition excludes catheter-induced dissection, coronary extension of an aortic dissection, and injury caused by chest trauma. Plaque rupture with cavitation is not SCAD either, although atherosclerosis and spontaneous dissection may coexist in the same person; its noniatrogenic nature is part of the diagnosis. Correctly identifying the mechanism changes revascularization and antithrombotic therapy.

Contemporary cohorts comprise about nine tenths women, with a mean age around 50 years, but this distribution must not become an exclusion criterion. Men, older women, and people with hypertension, dyslipidemia, or diabetes may have SCAD; the female phenotype raises pretest probability. Diagnosis remains anatomical and does not depend on the absolute absence of atherosclerotic factors.
Frequency is underestimated because the commonest patterns are long, smooth stenoses rather than the classic double-lumen image. In selected populations, SCAD explains an important proportion of infarctions in young women, while it is a minority among unselected acute coronary syndromes; angiographic recognition determines every epidemiological estimate. Percentages from expert centers cannot automatically be transferred to the general population.

The clinical strategy differs from that for atherothrombotic infarction: a stable lesion often tends to heal, and instrumentation may propagate it. Management must integrate hemodynamic status, persistent ischemia, anatomy, ventricular function, and systemic vascular vulnerability; mechanism-based diagnosis precedes definitive treatment. Therapy appropriate for a ruptured plaque may be unnecessary or harmful when the problem is intramural hemorrhage.

Etiology, risk factors, pathogenesis, and pathophysiology

SCAD has no single sufficient cause. The most coherent current model involves a constitutionally vulnerable wall acted on by hemodynamic, hormonal, and sometimes inflammatory stresses. Most cases remain sporadic and are not explained by a Mendelian genetic syndrome; arteriopathic vulnerability is therefore multifactorial. An associated factor indicates predisposition or precipitation but rarely proves the origin of an individual event by itself.
In the inside-out model, an intimal discontinuity allows luminal blood to enter the wall and create a false channel. Pressurized flow separates the planes of the media and may propagate longitudinally, progressively compressing the true lumen; the intimal tear is the entry point; this mechanism most directly explains the angiographic pattern with a flap, double lumen, and contrast staining.

In the outside-in model, the initial event is hemorrhage within the media, potentially arising from vasa vasorum or dysfunctional microvessels, without a recognizable primary intimal breach. The hematoma grows within the wall and pushes inward, producing a long, smooth stenosis. Intramedial hemorrhage precedes luminal communication. The prevalence of patterns without a visible tear and some imaging data support this model, without excluding coexistence or succession of the two processes.
In both models, the final consequence is increased pressure in the false cavity and eccentric compression of the true lumen. Ischemic severity depends on the vessel, length, location, side branches, propagation rate, and collateral capacity. The intramural hematoma is the main obstructive determinant. Luminal thrombus may arise secondarily, but SCAD is not defined by primary thrombosis or atherothrombosis.

Fibromuscular dysplasia is the most frequent associated extracoronary arteriopathy. It is a nonatherosclerotic, noninflammatory disease of medium-sized arteries, recognized mainly in renal, cervical, and iliac beds; prevalence detected after SCAD varies greatly with screening extent and quality; fibromuscular dysplasia signals systemic vulnerability. It must not be equated with SCAD: many patients have only one condition, and linear causality is unproven.
Coronary tortuosity, aneurysms, extracoronary dissections, and migraine recur more often in SCAD cohorts than in reference populations. Rare connective tissue syndromes, including vascular Ehlers-Danlos, Loeys-Dietz, and Marfan forms, explain only a small selected minority; associated arteriopathies broaden the vascular phenotype. Indiscriminate genetic testing has low yield and is reserved for syndromic signs, family history, or suggestive aortic and arterial abnormalities.

Genomic studies show a polygenic component, with loci partly shared with fibromuscular dysplasia and vascular regulation. The PHACTR1/EDN1 association is replicated, but no common variant currently predicts an individual event or guides clinically validated family screening; polygenic predisposition is not determinism. Asymptomatic relatives do not routinely undergo coronary imaging solely because of the proband's diagnosis.
Intense emotional stress and physical exertion, particularly isometric effort or effort with Valsalva, are reported before the event in some patients. They are possible precipitants through peaks in pressure, heart rate, catecholamines, and wall stress, not universal causes or behavioral blame; hemodynamic stress may trigger the event. Many SCADs occur during ordinary activity, and absence of an identifiable stressor does not weaken the diagnosis.

Pregnancy and puerperium combine hormonal changes in the vascular matrix with increased volume, output, and shear stress. Pregnancy-associated SCAD, or P-SCAD, is rare in absolute terms but an important cause of maternal infarction, especially in the weeks after delivery; the peripartum period is a high-impact setting. Not all SCAD patients have been pregnant, and exogenous hormonal exposure alone does not prove causality.
Systemic inflammatory diseases are reported in a minority, but typical SCAD is not vasculitis. Hypertension may increase wall stress and has been associated with recurrence in registries; smoking and dyslipidemia do not have the same causal role as in atherosclerosis; traditional factors must be treated when present. Their recognition does not justify automatic statin therapy or reclassify spontaneous hematoma as plaque rupture.

Pathological anatomy, classification, and progression

Separation most often involves the outer portion of the media, with blood accumulating between media and adventitia and compressing the wall toward the lumen. Available histology mainly comes from fatal events or historical specimens and may not represent contemporary surviving SCAD. Medial dissection defines the wall lesion. Periadventitial eosinophilic infiltrates described in some specimens may be a consequence of injury rather than evidence of causal vasculitis.
The left anterior descending artery and its branches are involved most often, followed by the circumflex and right coronary arteries; mid and distal segments predominate. Left main involvement is rare, while multiple vessels are affected during the same event in a meaningful minority; the mid-distal distribution is a diagnostic clue. An ostial or proximal lesion is possible, particularly in severe presentations, and does not exclude SCAD.

The Saw classification describes types 1 to 3; a later extension defines complete coronary occlusion as type 4. It organizes the luminographic appearance, not the histological mechanism, and helps recognize forms without a double lumen. It must be applied together with vessel course, tortuosity, calcification, other segments, and clinical context. The angiographic pattern guides initial diagnosis. When two mechanisms remain plausible, the category must not be turned into artificial certainty.

Angiographic classification of SCAD

• Type 1: a radiolucent flap or double lumen, with contrast retention or staining in the wall; the classic but not the most frequent appearance.
• Type 2A: long, smooth, diffuse stenosis, often with abrupt narrowing and recovery of normal distal caliber before the end of the vessel.
• Type 2B: long, regular stenosis continuing to the distal end of the vessel, without a terminal segment that becomes normal again.
• Type 3: short focal or tubular stenosis mimicking atherosclerosis and often requiring OCT or IVUS if confirmation changes management.
• Type 4: complete occlusion, generally distal, in which the course and healing may distinguish SCAD from thromboembolism or another occlusion.

Type 1 shows communication with the false lumen and is the most intuitive form, but is a minority in modern registries. Persistent contrast requires cautious injection because excessive pressure or deep catheter engagement may extend separation; a double lumen is highly suggestive in the right context. It must be distinguished from overlapping flow, a side branch, spasm, artifact, and dissection caused by the procedure itself.
Type 2 is the dominant phenotype and mainly reflects compression by an intramural hematoma. Length often exceeds that of a focal plaque, and abrupt transition from normal caliber to stenosis and distal involvement help but are not pathognomonic; a long uniform stenosis should raise suspicion of SCAD. Comparison with adjacent segments and multiple projections prevent a naturally narrow vessel from being mistaken for a dissecting lesion.

Type 3 may be almost indistinguishable from an atherosclerotic stenosis, especially in a patient with risk factors or concomitant disease. Diagnostic certainty must match the consequences: a lesion destined for stenting may benefit from intracoronary imaging, while one clearly suited to conservative management should not be crossed unnecessarily. Atherosclerotic mimicry is the main diagnostic risk. Calcification and diffuse plaque favor atherosclerosis but do not prove it caused the index stenosis.
Type 4 extends classification to total occlusions, often in small distal branches. Angiographic appearance alone may not distinguish hematoma, thrombus, embolus, or chronic occlusion; clinical profile, upstream morphology, and subsequent healing become essential. A distal occlusion requires an explicit differential diagnosis. Forcing a wire into a small uncertain vessel may cause perforation or extension without benefit to salvageable myocardium.

Healing occurs through hematoma resorption, restoration of the true lumen, and wall remodeling. In Hassan's angiographic study, 86.3 percent of reassessed lesions had healed; when follow-up occurred at least 30 days later, the proportion was 95 percent; angiographic healing is time-dependent; these data concern selected lesions undergoing repeat angiography and do not mandate systematic invasive follow-up in every patient.
During the first days, the hematoma may still propagate, narrow the true lumen, or involve a branch, causing new symptoms, ECG changes, or rising troponin; consensus statements therefore suggest inpatient observation for conservatively managed patients, often three to five days according to the presentation and resources. Early extension differs from late recurrence. Initial stability does not authorize immediate discharge without adequate clinical surveillance.

Later, the index lesion may be completely recanalized while predisposition to a new dissection remains in another artery or separate segment. De novo recurrence is therefore not simply reopening of the old wound and may have different anatomy; residual vascular vulnerability survives local healing; this distinction explains why documenting a healed vessel does not remove the need for education, follow-up, and assessment of new symptoms.

Clinical manifestations

Almost all clinically diagnosed cases present as an acute coronary syndrome. Chest pain or pressure is dominant and may be accompanied by radiation, dyspnea, nausea, vomiting, sweating, or an intense sense of alarm; acute chest pain requires prompt ECG and troponin testing. Young age and absence of atherosclerotic factors must not lead to discharge before myocardial injury has been excluded.
In prospective cohorts, NSTEMI is more common than STEMI, but both are frequent and reflect the location, severity, and duration of impaired flow. An initially normal troponin does not exclude a very early event and must be interpreted according to onset and a serial algorithm; the STEMI or NSTEMI phenotype does not identify the mechanism. The ECG may be normal or nonspecific when the territory is small or flow varies.

Palpitations, syncope, ventricular tachycardia, ventricular fibrillation, and cardiac arrest occur in a minority, more likely with extensive ischemia or severe ventricular dysfunction. Cardiogenic shock and acute heart failure require urgent action regardless of the general preference for conservative treatment. Hemodynamic instability immediately changes priorities. Long-term arrhythmic risk is subsequently estimated from ventricular function, scar, and events not attributable to a reversible cause.
The typical setting is a woman without previous obstructive coronary disease, but the profile is not uniform. Hypertension is present in some patients, while diabetes and marked dyslipidemia are less common than in atherosclerotic infarction; men and postmenopausal women may nevertheless show identical patterns; demographic probability guides but does not conclude. Ambiguous angiography must be assessed for SCAD even when the patient does not fit the stereotype.

An intense emotional event or physical exertion is frequently reported, with differences by sex and history-taking method. Temporal proximity does not prove that stress was necessary or sufficient and must not place blame on the patient; the possible precipitant completes the history. Reconstructing intensity, type of effort, and symptoms is more useful than permanently banning every activity.
P-SCAD occurs during pregnancy or, more often, early puerperium and in several series shows more proximal, multivessel, or left main involvement. It may cause extensive infarction, ventricular dysfunction, shock, and need for revascularization more often than many nongestational SCADs; the pregnancy-associated phenotype is more severe on average. Postpartum chest pain therefore requires urgent cardiac assessment and must not automatically be attributed to anxiety or muscular disorders.

Intense physical precipitants are more frequently described in men, but cohorts are smaller and differences do not permit individual rules. Men should also be assessed for fibromuscular dysplasia, aneurysms, and other extracoronary abnormalities according to the same clinical reasoning. SCAD in men is not an impossible exceptional diagnosis. Sex changes neither angiographic criteria nor the indication for more aggressive PCI without other reasons.
Recurrent chest pain after the event is common and may persist without a new dissection. Vasomotor abnormalities, post-infarction sensitization, musculoskeletal pain, anxiety, and cyclic variations are possible, but none should be presumed before ischemia is excluded when symptoms are new or typical. Post-SCAD pain is not automatically recurrence. Duration, ECG, troponin, instability, and similarity to the index event determine investigation urgency.

Anxiety, depression, fear of recurrence, and post-traumatic symptoms affect quality of life, especially when the person was young and previously considered healthy. Avoiding all exertion may worsen deconditioning and isolation, while minimizing the experience impairs follow-up adherence; the psychological burden is part of the clinical condition. Consistent information, rehabilitation, and professional support are components of care, not mere adjuncts.

Investigations and diagnosis

Initial assessment follows that for every suspected acute coronary syndrome: vital signs, ECG within minutes, serial tracings, high-sensitivity troponin, full blood count, renal function, and electrolytes. Treatment of instability is not delayed while defining the coronary wall; the urgent syndromic diagnosis documents ischemia and acute myocardial injury. No troponin value or ECG pattern alone distinguishes SCAD, plaque rupture, embolism, or vasospasm.
Echocardiography assesses global and regional ventricular function, mitral regurgitation, mechanical complications, and alternative diagnoses. A regional abnormality matching the suspected vessel strengthens causality, while a normal study does not exclude a small distal infarction or a lesion with preserved flow; regional motion quantifies myocardial consequences. Initial ejection fraction may improve, so permanent prognostic decisions require reassessment after recovery.

Invasive coronary angiography is the first-line examination in acute infarction and remains the diagnostic cornerstone of SCAD. It must be read in multiple projections, following the vessel to distal branches and seeking abrupt transitions, long narrowing, tortuosity, and absence of diffuse atheroma; expert coronary angiography recognizes most cases. The report should describe angiographic type, segment, length, TIMI flow, involved branches, and degree of certainty.
The procedure requires caution because a vulnerable wall increases iatrogenic dissection risk. The catheter must not be deeply engaged and injections should avoid unnecessary pressure; every guidewire passage needs a concrete diagnostic or therapeutic benefit; atraumatic manipulation reduces procedural harm. A new ostial dissection arising during the examination must be distinguished from the spontaneous lesion prompting laboratory access.

OCT provides very high-resolution images of the intima-media membrane, true and false lumens, hematoma, and possible communications. It requires contrast injection to displace blood, which may pressurize the false lumen or propagate the lesion; OCT resolution clarifies superficial detail. It is used chiefly for ambiguous type 3 lesions or during PCI when the vessel is large enough and the answer will truly change management.
IVUS has lower resolution but deeper penetration, visualizes hematoma extent through the wall, and does not require the same contrast flushing as OCT. The IVUS catheter must still cross the lesion and may enter the false lumen or extend dissection; IVUS penetration complements wall imaging. Choice depends on anatomy, experience, diagnostic question, and safety, not a universal hierarchy.

Intracoronary imaging is unnecessary in convincing type 1 or typical type 2 intended for conservative treatment. Its indication increases when SCAD and atherosclerosis would entail different treatments or when urgent revascularization requires confirmation of the true lumen; the principle of proportionality limits invasive procedures. A better image is no advantage if obtaining it poses more risk than its chance of changing outcome.
CCTA is not sensitive enough to exclude acute distal SCAD: small caliber, motion, wall apposition, and spatial resolution may yield a false-normal study. It can selectively document healing in proximal or large-caliber segments and assess other structures; coronary CCTA has a complementary role. A negative finding in a patient with infarction neither replaces angiography nor erases a compatible invasive pattern.

Cardiac magnetic resonance imaging defines edema, necrosis, scar, function, and ischemic distribution; it is particularly helpful when angiography is uncertain or myocarditis and Takotsubo syndrome must be distinguished. Distal SCAD may cause a small infarction at the limits of resolution; myocardial characterization confirms the tissue consequence. CMR does not reliably visualize every dissection and must not be used as the sole evidence about the coronary wall.
After the acute phase, vascular assessment from head to pelvis is recommended, generally once, with CT or MR angiography. The aim is to seek fibromuscular dysplasia, aneurysms, dilations, and dissections in cervical, intracranial, renal, mesenteric, and iliac territories; extracoronary screening changes surveillance and counseling. Examination and protocol must balance radiation, contrast, renal function, resolution, and availability, without automatic repetition in the absence of findings or symptoms.

A diagnosis of fibromuscular dysplasia requires appropriate signs in an extracoronary bed, such as multifocal alternating stenoses and dilations or a compatible focal lesion, not tortuosity alone. Aneurysms and dissections may coexist without meeting FMD criteria; the complete vascular phenotype must be documented separately. Blood pressure, bruits, pulses, and neurological symptoms guide further testing and vascular specialist consultation.
Genetic testing is not routine because monogenic syndromes account for a small proportion. Genetic assessment is appropriate with suggestive hypermobility or fragility, aortic aneurysm, multiple dissections, a syndromic phenotype, a family history of early arteriopathy, or unexplained vascular death; targeted genetic selection increases clinical yield. Results require counseling and variants of uncertain significance must not be assigned causality.

The differential diagnosis includes atherosclerosis, vasospasm, embolism, in situ thrombosis, myocardial bridging, artifacts, and iatrogenic dissection. A distal type 4 occlusion may remain probabilistic; OCT or IVUS can be decisive in type 3, while intracoronary nitrate helps recognize spasm; the angiographic differential diagnosis avoids discordant treatment. When uncertainty persists, the report should state alternatives, supporting evidence, and a reassessment plan instead of a falsely definitive label.

Treatment and prognosis

In stable patients without persistent ischemia, left main involvement, or critically reduced flow to a large territory, the preferred strategy is conservative. The rationale is biological and technical: the wall frequently heals, while PCI may propagate hematoma and dissection; conservative management is an active choice. It includes monitoring, symptom control, ventricular assessment, and prompt reassessment if pain, ECG, biomarkers, or stability worsen.
Inpatient observation generally continues for several days because many clinically important extensions occur early. Duration is not rigid: a proximal location, reduced flow, recurrent pain, arrhythmias, and ventricular dysfunction require more caution than a stabilized small distal lesion. Early surveillance detects deterioration. New symptoms require ECG and troponin, followed by urgent imaging when objective signs or instability exist.

PCI is reserved mainly for ongoing or recurrent ischemia, hemodynamic instability, threatening arrhythmias attributable to the vessel, left main disease, or a proximal segment endangering substantial myocardium. The decision also depends on flow, collaterals, and center experience; selective revascularization goes beyond an isolated anatomical threshold. A severe-looking distal stenosis that is stable with adequate flow may favor observation.
PCI is difficult because the wire may enter the false lumen, a balloon may push hematoma beyond the margins, and a short stent may not cover propagation. After hematoma resorption, a long stent may become malapposed; side-branch occlusion is another risk; the difficulties of PCI must be anticipated. Intracoronary imaging, extended stenting, or decompression techniques are selected case by case by experienced operators, with no universally superior technique.

Coronary bypass is considered for left main or proximal multivessel dissection, extensive ischemia not controllable percutaneously, or failed PCI. It may save substantial myocardium, but healing of the native vessel restores competitive flow and favors later graft occlusion; rescue bypass addresses immediate risk. Late graft patency alone does not measure success if myocardium remains viable and the native coronary has healed.
Thrombolysis must be avoided when SCAD is known or strongly suspected, even with ST elevation. It may increase wall bleeding, extend dissection, and turn a manageable lesion into a surgical emergency; contraindicated thrombolysis is a crucial difference from atherothrombotic STEMI. When immediate anatomical diagnosis is unavailable, urgent transfer to a center with angiography is particularly important.

Anticoagulation started for an acute coronary syndrome is generally reassessed and stopped after SCAD is confirmed, unless there is an independent indication such as atrial fibrillation, ventricular thrombus, or venous thromboembolism. Concern is hematoma expansion, but specific randomized comparisons are lacking; stopping anticoagulation still requires individual judgment. Theoretical wall risk must be balanced against the documented risk of the condition prompting treatment.
After PCI with a stent, antiplatelet therapy follows device and acute syndrome needs, adapted to bleeding risk. In conservatively managed SCAD, aspirin monotherapy is common, whereas the need and duration of dual therapy remain uncertain and differ among experts; the antiplatelet strategy is not defined by conclusive trials. DISCO and the Australian-New Zealand cohort found unfavorable associations with more intensive regimens, but confounding and selection prevent causal conclusions.

Beta-blockers reduce heart rate, pressure, and wall stress and are often prescribed, especially with hypertension, arrhythmia, or ventricular dysfunction. Use was associated with less recurrence in one registry, but the evidence is observational and may reflect patient characteristics; tolerated beta-blockade is reasonable during follow-up. Drug and dose are adapted to blood pressure, bradycardia, fatigue, bronchospasm, and rehabilitation goals.
ACE inhibitors or angiotensin receptor blockers are indicated for ventricular dysfunction, heart failure, or hypertension according to standard recommendations. Statins do not treat wall fragility and are not prescribed solely for SCAD; they remain appropriate for dyslipidemia or another independent cardiovascular indication. Indication-guided therapy avoids atherosclerotic reflexes. Nitrates and calcium channel blockers may be considered for angina or vasospasm, according to symptoms and pressure.

Specifically adapted cardiac rehabilitation promotes physical recovery, adherence, and psychological safety. Moderate aerobic activity is gradually reintroduced with warm-up, blood pressure control, and individualized loads; extreme exertion, maximal lifting, prolonged Valsalva, and unevaluated competition are avoided. Personalized rehabilitation does not mean permanent inactivity. Rigid weight limits lack a universal basis and should be replaced by breathing technique, progression, and perceived exertion.
Before a future pregnancy, cardio-obstetric counseling, assessment of ventricular function, completion of vascular screening, and review of potentially teratogenic drugs are required. Many experts discourage pregnancy after SCAD, but the decision must respect individual risk and informed preferences. Preconception counseling explains uncertainty and alternatives. Pregnancies observed in selected survivors have often been favorable, but selection and small numbers do not establish zero risk.

If pregnancy is undertaken, care involves cardiology, maternal-fetal medicine, anesthesia, and a center able to manage coronary emergencies. Blood pressure, symptoms, ventricular function, and delivery plan are individualized; cesarean delivery is not automatically safer, and vaginal delivery may be appropriate in many stable cases. Cardio-obstetric management must be planned before delivery. Analgesia, reduction of prolonged pushing, and monitoring depend on hemodynamic profile, not a single rule.
In the contemporary Canadian cohort, predominantly managed conservatively, three-year mortality was 0.8 percent, recurrent infarction 9.9 percent, and major cardiovascular events 14 percent. De novo SCAD recurrence was 2.4 percent; contemporary prognosis is generally favorable but not benign. Estimates depend on selection, diagnostic confirmation, definitions, and follow-up and must not be presented as an exact personal risk.

Complications

The main immediate complication is myocardial infarction, whose extent depends on the territory and duration of true-lumen compression. A distal vessel may produce a small scar, whereas the left main, proximal left anterior descending artery, or multivessel dissection may compromise a large ventricular mass. Residual myocardial damage determines prognosis and therapy. Edema and stunning may regress, but extensive necrosis causes remodeling, heart failure, and persistent arrhythmic risk.
Early extension may present with new pain, dynamic ECG changes, a further troponin rise, or worsening flow. Not every symptom fluctuation is propagation, so repeat angiography must integrate objective signs and the amount of threatened myocardium. Intramural progression is most relevant early. Persistent ischemia or instability requires reassessment of conservative management and possible revascularization.

Ventricular tachycardia, ventricular fibrillation, and cardiac arrest may complicate acute ischemia. After recovery, defibrillator implantation does not follow from SCAD itself but from general criteria based on persistent ventricular dysfunction, arrhythmias not attributable solely to a reversible phase, and individual risk. Arrhythmic risk must be reassessed over time. An event during acute ischemia does not automatically establish a need for permanent device therapy.
Cardiogenic shock, pulmonary edema, and ischemic mitral regurgitation are more likely with proximal, multivessel, or pregnancy-associated involvement. Mechanical support may be necessary, but access and cannulas require care when dissections or fragility coexist in other arterial beds; hemodynamic compromise requires an expert team. Revascularization, circulatory support, surgery, and intensive care are coordinated according to myocardial territory and overall anatomy.

Iatrogenic complications include catheter-induced dissection, hematoma propagation, perforation, branch loss, stenting of the false lumen, and acute closure. Prevalence is higher than during intervention on ordinary atherosclerotic arteries, consistent with wall fragility and long lesion geometry; iatrogenic dissection may create a second acute problem. Avoiding unnecessary procedures and assigning complex cases to specifically experienced operators are primary prevention.
After PCI, hematoma resorption may leave malapposed stent segments; after bypass, restored native flow may cause competition and graft occlusion. These outcomes do not always mean ischemia, but explain why anatomical revascularization is not the default solution for every severe-looking SCAD. Post-intervention healing changes late geometry. Follow-up is guided by symptoms, function, and clinical consequences, not indiscriminate pursuit of perfect patency.

Recurrence may be extension of the index lesion, iatrogenic dissection during assessment, or new spontaneous SCAD in a separate segment. Older studies with longer follow-up reported higher percentages than some recent cohorts, partly because definitions and selection differ; de novo recurrence remains unpredictable for an individual. Hypertension is a plausible modifiable factor, and beta-blockade is associated with lower observational recurrence, not guaranteed protection.
Fibromuscular dysplasia, intracranial aneurysms, or other dissections introduce independent extracoronary risks. A positive finding requires surveillance specific to site, size, symptoms, and family history; there is no identical imaging frequency for every abnormality; extracoronary complications justify initial screening. A new neurological deficit, sudden headache, or intense neck or abdominal pain requires urgent assessment of the suspected territory.

A future pregnancy may entail new SCAD or heart failure if ventricular dysfunction persists. The Tweet study found no statistically significant association between subsequent pregnancy and recurrence in a selected group, but small numbers, survivor selection, and a favorable profile limit reassurance. Reproductive risk cannot be quantified precisely for an individual. Shared decision-making considers index-event severity, function, arteriopathies, and the center's ability to manage an emergency.
Recurrent pain, repeated emergency visits, fear of exertion, and post-traumatic disorder may persist longer than the angiographic lesion. Reassurance must be precise: most pain is not a new SCAD, but every episode with ischemic features deserves a consistent clinical pathway; psychosocial morbidity may limit recovery. Rehabilitation, psychotherapy when indicated, and a written symptom plan reduce both avoidance and uncontrolled medicalization.