Coronary vasculitis

Article written and reviewed by Dr Luca Moretti

Coronary vasculitis denotes inflammatory involvement of the coronary artery wall or, in some diseases, perivascular tissue capable of compromising lumen and integrity. It is not one entity but a phenotype shared by vasculitides with different biology, vessel caliber, and treatment; consequences include coronary stenosis, occlusion, aneurysm, ectasia, and thrombosis. One lesion may combine dilation and narrowing. Etiologic diagnosis determines immunological therapy.
Kawasaki disease is the most important pediatric model, while adult involvement is documented chiefly in Takayasu arteritis, polyarteritis nodosa, and Behçet disease. Giant cell arteritis, ANCA-associated vasculitides, and IgG4-related disease affect the coronary arteries more rarely. Clinical rarity limits specific trials. Many recommendations derive from the causal systemic vasculitis. Coronary decisions require multidisciplinary expertise.

Active inflammation may cause edema, necrosis, and thrombosis; healing may leave fibrosis, intimal proliferation, stenosis, or permanent aneurysmal remodeling. Normalization of fever and inflammatory markers therefore does not equal anatomical restoration; vascular damage must be distinguished from current immunological activity. The former may require revascularization, the latter disease-specific therapy.
A coronary syndrome in a young patient, ostial stenosis associated with aortitis, multiple aneurysms, or a childhood history compatible with Kawasaki disease should broaden the differential beyond atherosclerosis. Autoimmune disease alone does not prove coronary arteritis; a causal link requires anatomical and clinical consistency. Accelerated atherosclerosis and vasculitis may coexist. Infection and iatrogenic pseudoaneurysm must be excluded.

Management integrates stabilization of ischemia, identification of vasculitis, control of inflammation, and treatment of structural lesions. In an emergency, an occlusion with infarction does not await the full rheumatological work-up; elective procedures are preferably performed during controlled disease when possible. Therapeutic priority changes with immediate risk. Immunosuppression and revascularization are not alternatives and often address different problems in the same patient.
Coronary epidemiology cannot be summarized by one prevalence because definitions, screening intensity, and populations differ. Coronary imaging is systematic in Kawasaki disease but often symptom-driven in adult vasculitis, probably underestimating silent forms. The epidemiological denominator changes every percentage. Autopsy series and clinical registries select different phenotypes. Rarity does not justify indiscriminate coronary screening.

Etiology, risk factors, pathogenesis, and pathophysiology

Kawasaki disease is an acute febrile childhood vasculitis of unknown cause. An aberrant immune response in susceptible children causes necrotizing arteritis, subacute vasculitis, and later luminal remodeling; without treatment, about one quarter develop coronary dilation or aneurysms. Intravenous immunoglobulin markedly reduces this risk. Age below six months and a high initial Z score identify greater risk.
In polyarteritis nodosa, segmental necrotizing inflammation affects medium and small arteries without glomerulonephritis or capillary vasculitis. Coronary arteries may develop irregular narrowing, thrombosis, and multiple aneurysms, sometimes with a beaded angiographic appearance; transmural necrosis weakens the wall. A minority of cases is associated with hepatitis B virus. Treatment of viral PAN differs from idiopathic PAN.

Takayasu arteritis predominantly affects the aorta and major branches in young people, especially women. Extension to the aortic root may narrow one or both coronary ostia; long lesions, aneurysms, or distal involvement are less common; ostial stenosis results from contiguous aortitis and fibrosis. It may cause extensive ischemia despite preserved distal coronaries. Systemic activity and coronary anatomy do not always progress together.
Giant cell arteritis affects people older than 50 and typically involves cranial and large arteries. Direct coronary involvement is rare and may be difficult to distinguish from common atherosclerosis at this age; proximal aortitis may extend to the ostia. Myocarditis and pericarditis are alternatives. A coronary syndrome must not automatically be attributed to GCA.

Behçet disease is variable-vessel vasculitis affecting arteries and veins. True aneurysms or pseudoaneurysms, stenosis, and thrombosis are described in coronary arteries, often in patients with recurrent oral ulcers and other typical manifestations. Perivascular inflammation may compromise anastomoses and puncture sites. Thrombosis develops in an inflammatory environment. Bleeding risk rises when aneurysms coexist.
Granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis are ANCA-associated small-vessel vasculitides, with frequent serological exceptions. Epicardial coronary arteritis is rare; in EGPA, cardiac injury more often results from eosinophilic infiltration, myocarditis, or microvascular disease. ANCA positivity does not localize injury. Coronary arteritis, myocarditis, and vasospasm may mimic one another. MRI and angiography clarify different compartments.

IgG4-related disease may cause aortitis, periarteritis, and fibroinflammatory pericoronary masses, sometimes with dilation or stenosis. A cuff around the vessel may be more evident than luminal injury; a pericoronary pseudomass requires differentiation from cancer and infection. Normal serum IgG4 does not exclude disease. Histology from an accessible organ remains particularly useful.
Systemic lupus erythematosus, rheumatoid arthritis, sarcoidosis, and other inflammatory diseases have been associated with coronary lesions, but accelerated atherosclerosis, thrombosis, or myocardial injury may be more common than direct arteritis. Syphilis, endocarditis, and other infections may affect ostia or wall; the differential diagnosis avoids dangerous immunosuppression. An infected aneurysm requires antimicrobial treatment and surgical control. Serology alone does not prove coronary vasculitis.

Immune mechanisms differ among diseases and do not justify uniform therapy. Immune complexes and complement may matter in some phenotypes, anti-MPO or anti-PR3 antibodies participate in ANCA vasculitis, while T cells, macrophages, and cytokines sustain large-vessel arteritis; the immunological signature is not interchangeable. A drug effective in one vasculitis may be inappropriate in another. Coronary involvement does not erase these biological differences.

Pathological anatomy, classification, and progression

International classifications organize vasculitides by predominant vessel size, but one disease may affect vessels of different sizes. Kawasaki disease and PAN are medium-vessel vasculitides; Takayasu and GCA are large-vessel forms; Behçet is variable-vessel vasculitis; predominant caliber guides the coronary pattern but is not an absolute boundary. The epicardial coronary artery has features of a medium muscular artery.
In acute arteritis, the wall may show inflammatory infiltrate, edema, and fibrinoid necrosis, with interruption of elastic laminae and smooth muscle loss. Weakening promotes dilation, while intimal edema and thrombosis reduce the lumen; elastic destruction predisposes to aneurysm. Repair deposits collagen and matrix. The same lesion may subsequently become stenotic.

Three interconnected processes are described in Kawasaki disease: early self-limited necrotizing arteritis, subacute or chronic vasculitis, and luminal myofibroblastic proliferation. Aneurysms may regress in size, but the wall remains biologically abnormal and may develop thrombosis, calcification, or late stenosis. Luminal remodeling is not histological healing. Giant aneurysms rarely normalize. Maximum Z score remains meaningful throughout life.
Takayasu coronary lesions have three main patterns: ostial and proximal stenosis or occlusion, diffuse or focal arteritis of epicardial segments, and coronary aneurysm. The first is far more common; continuity with aortitis explains ostial involvement. Fibrosis may persist after inflammation is suppressed. A graft should be anastomosed to the healthiest possible tissue.

PAN produces segmental lesions at different points in one vessel and in different arteries. Coexisting microaneurysms, stenoses, occlusions, and collaterals reflect asynchronous inflammation and healing; the multifocal pattern may involve renal, mesenteric, and coronary arteries. Absence of aneurysms does not exclude PAN. Skin, nerve, or muscle biopsy may document systemic vasculitis.
A true aneurysm retains altered wall layers, while a pseudoaneurysm is a rupture contained by perivascular tissue and is more prone to rupture. This distinction affects urgency and technique in vasculitis; saccular morphology raises suspicion of pseudoaneurysm. CCTA and intravascular imaging may clarify the wall. Angiography shows only the lumen and may not distinguish them.

Thrombosis develops from stasis in dilated segments, exposure of damaged surfaces, and inflammatory activation of coagulation. It may remain mural, embolize distally, or occlude the aneurysm and adjacent branches; in situ thrombosis does not demonstrate atherosclerosis. Organized thrombus may mimic concentric stenosis. Antithrombotic selection depends on disease and anatomy.
Evolution must be described by separating activity, damage, and complications. Imaging may show less wall edema without change in fibrotic stenosis, or aneurysm growth despite attenuated systemic symptoms; longitudinal monitoring compares diameters and lumen with the same method. Pediatric measurements require Z scores. Adults require absolute diameter and ratio to the reference.

Late calcification chiefly represents chronic damage and is frequent in evolved Kawasaki aneurysms but does not measure current activity. A calcified segment may contain organized thrombus and a lumen far smaller than its external diameter; vasculitic calcification must be separated from the atherosclerotic calcium score. Proximal distribution and morphology provide clues. Age and clinical history remain indispensable.

Clinical manifestations

Coronary vasculitis may be asymptomatic and appear during imaging for systemic disease. Clinical relevance depends on territory, stenosis progression, and thrombus; an incidental finding requires anatomical confirmation and etiologic assessment. Not every irregularity is active arteritis. Symptoms and ischemia must be assessed independently of diameter.
Exertional angina results from ostial or segmental stenosis limiting coronary reserve. It may be retrosternal pressure, dyspnea, or reduced functional capacity and has no features specific to vasculitis; a progressively lower ischemic threshold suggests worsening. Bilateral ostial disease may compromise large territories. Stable presentation does not exclude high-risk anatomy.

Resting pain, ECG changes, and elevated troponin define an acute coronary syndrome that may result from aneurysmal thrombosis, occlusion of inflammatory stenosis, distal embolization, or concomitant atherothrombosis. Mechanism cannot be inferred from the vasculitis label alone; an acute presentation requires immediate cardiac care. Intracoronary imaging may define the substrate. Etiologic treatment follows stabilization.
In children with Kawasaki disease, coronary involvement is often silent during the febrile phase and identified by echocardiography. Irritability, nonexudative conjunctivitis, rash, oral changes, extremity changes, and lymphadenopathy guide clinical diagnosis; an incomplete form may lack several classic signs. Aneurysms do not necessarily cause pain. Timely imaging must not await a late complete presentation.

In adults, limb claudication, blood pressure differences, reduced pulses, and vascular bruits support Takayasu arteritis; new headache, jaw claudication, and visual symptoms suggest GCA. Oral and genital ulcers, uveitis, or thrombosis indicate Behçet disease; systemic signs raise pretest probability. They may be absent during coronary recurrence. A detailed treatment history is indispensable.
Fever, weight loss, fatigue, myalgia, and arthralgia are common but nonspecific inflammatory manifestations. Their absence does not exclude a scar lesion or partially treated vasculitis, and their presence does not prove coronary involvement; clinical discordance is common in large-vessel arteritis. CRP and ESR may be suppressed by drugs. Invasive decisions must not rest on one biomarker.

Syncope, palpitations, pulmonary edema, or shock indicates extensive ischemia, arrhythmia, or ventricular dysfunction. In some vasculitides, myocarditis, pericarditis, aortic valve disease, and renovascular hypertension coexist, each capable of altering symptoms; cardiac involvement must be phenotyped. MRI distinguishes scar from myocardial inflammation. Echocardiography assesses function, valves, and hemodynamic complications.
Manifestations may appear during apparent systemic remission. Advanced fibrotic stenosis may become symptomatic as demand rises, while aneurysmal thrombosis may occur without renewed fever or CRP elevation; clinical remission does not mean zero coronary risk. Anatomical follow-up depends on historical damage. New symptoms require reassessment even with unchanged biomarkers.

Investigations and diagnosis

Initial assessment includes systemic history, complete vascular examination, ECG, troponin for acute symptoms, blood count, renal and liver function, ESR, and CRP; these measure consequences and context but do not alone confirm coronary arteritis; inflammatory markers have incomplete sensitivity. Eosinophilia suggests EGPA but has differential diagnoses. Hematuria and proteinuria suggest small-vessel vasculitis.
ANCA with PR3 or MPO specificity, complement, ANA, cryoglobulins, infectious serology, and IgG4 concentration are requested according to phenotype. A positive result changes probability but must be compared with clinical criteria and organs involved; indiscriminate testing increases false positives. Elevated IgG4 is nonspecific. Negative ANCA does not exclude EGPA or other vasculitides.

Echocardiography is central in Kawasaki disease because it visualizes proximal segments and permits body-surface-area-normalized measurements. It must document the left anterior descending and right coronary arteries, ventricular function, effusion, valves, and aortic root; the coronary Z score guides classification and follow-up. A normal initial study does not exclude later evolution. Distal segments require complementary methods when not evaluable.
CCTA reconstructs origin, course, wall, diameters, mural thrombus, calcification, and relationship to the aorta. It is particularly useful for aneurysms, proximal stenoses, and planning, with protocols adapted to heart rate and radiation dose; the anatomical map must include the entire coronary tree. Late calcification may indicate previous Kawasaki disease. Resolution alone does not demonstrate microscopic immunological activity.

Invasive angiography is reserved for acute syndromes, relevant ischemia, uncertain anatomy, or PCI planning. It quantifies lumen, collaterals, and stenoses but may underestimate wall thickening and adherent thrombus. Intracoronary imaging distinguishes wall, thrombus, and stent result. OCT requires caution with critical ostia and renal failure. IVUS offers deeper penetration and wall measurement.
MR angiography and fluorodeoxyglucose PET are used mainly for the aorta and major branches in Takayasu or GCA. MRI assesses thickening, edema, and enhancement; PET shows inflammatory metabolism but is affected by treatment, glycemia, and atherosclerosis; vascular PET does not adequately resolve small coronary arteries. An aortic signal may support context. No method alone defines remission with certainty.

Coronary biopsy is not routinely justified because of risk and focal disease. Histological diagnosis is sought in temporal artery, skin, nerve, muscle, kidney, or another accessible organ according to suspected disease; an extracoronary specimen may document IgG4 or granulomas. A negative biopsy is subject to sampling error. Sampling must not delay urgent GCA treatment.

Elements required to attribute a coronary lesion to vasculitis

• Coronary lesion documented with an appropriate anatomical method and definition of stenosis, aneurysm, thrombus, or ostial involvement.
• Consistent clinical, radiological, or histological diagnosis of a vasculitis capable of producing that pattern.
• Assessment of alternatives, including atherosclerosis, dissection, embolism, infection, and iatrogenic injury.
• Temporal or anatomical concordance between vasculitic activity and the lesion, without necessarily requiring elevated biomarkers.
• Multidisciplinary discussion when attribution changes immunosuppression or revascularization.

The differential diagnosis includes premature atherosclerosis, SCAD, embolism, vasospasm, congenital abnormalities, radiation, infection, and catheter or stent complications. In autoimmune disease, an ordinary plaque remains possible; in young people, a focal lesion is not automatically inflammatory; etiologic probability derives from the whole picture. Distribution and morphology guide reasoning. Empirical therapy must not replace rigorous diagnostic reconstruction.
Assessment of activity synthesizes symptoms, markers, serial imaging, and immunosuppressant dose. In large-vessel arteritis, wall enhancement and PET uptake may persist or be treatment-influenced without perfect histological correlation; activity judgment remains integrated and clinical. One positive test does not automatically require escalation. Objective vascular progression outweighs one ambiguous isolated signal.

In revascularized patients, CCTA, echocardiography, functional tests, and angiography are chosen according to grafts, stents, renal function, and likelihood of another procedure. Repeating examinations without an explicit question adds contrast, radiation, and false positives; multimodal surveillance does not mean using every technique. Each method must answer a different question. Comparison with the previous examination is part of interpretation.

Treatment and prognosis

Therapy is defined with cardiology, rheumatology or immunology, radiology, interventional cardiology, and cardiac surgery. Ischemic urgency must be separated from suppression of inflammation, coordinating anticoagulation, antiplatelet therapy, and immunosuppression to avoid bleeding or infection; a multidisciplinary team is essential in complex anatomy. Infection prophylaxis depends on the immunosuppressive regimen. Vaccination and reproductive risk must be planned.
In acute Kawasaki disease, intravenous immunoglobulin, generally 2 g/kg as one infusion, is combined with aspirin and given within ten days of fever onset, ideally as soon as diagnosis is established. High-risk patients may benefit from initial intensification according to validated protocols; early immunoglobulin reduces aneurysms. Corticosteroids, infliximab, or cyclosporine are selected in specific settings. Resistance to initial IVIG requires prompt reassessment.

Thromboprophylaxis in Kawasaki disease depends on maximum Z score and current status. The 2024 AHA strategy maintains low-dose aspirin for persistent aneurysms; clopidogrel may be added for medium aneurysms, while persistent large or giant aneurysms receive anticoagulation with warfarin, low-molecular-weight heparin, or, in selected settings, direct anticoagulants. Thrombotic risk rises with size and stasis. The regimen must follow updated pediatric tables. Pregnancy and physical activity require dedicated counseling.
Active Takayasu arteritis is treated with glucocorticoids and a nonsteroidal immunosuppressant because relapses are common with steroids alone. Methotrexate, azathioprine, mycophenolate, leflunomide, TNF inhibitors, or tocilizumab are selected by severity, experience, and response; control of aortitis precedes elective revascularization when possible. Critical ostial stenosis may require urgent intervention. Surveillance continues even without systemic symptoms.

In suspected GCA with ischemic risk, glucocorticoids must begin promptly without awaiting biopsy. Tocilizumab reduces relapse and cumulative steroid exposure in appropriate patients; GCA treatment primarily protects against documented cranial and aortic complications. No trials address rare coronary arteritis. Significant coronary stenosis follows revascularization principles adapted to inflammation.
Severe idiopathic PAN generally requires high-dose glucocorticoids and cyclophosphamide for induction, followed by maintenance with a less toxic drug. In hepatitis B-associated PAN, treatment integrates antivirals, brief immunological control, and, in specialist protocols, plasma exchange; HBV-associated disease must not be treated like idiopathic PAN. Prolonged immunosuppression may promote viral replication. Acute coronary disease requires simultaneous treatment.

In Behçet disease with pulmonary or peripheral arterial aneurysms, high-dose glucocorticoids and infliximab are recommended; cyclophosphamide is an alternative. Anticoagulation is not automatic because thrombosis and aneurysms may coexist; immune suppression reduces the vascular driver. Pulmonary aneurysms increase bleeding risk. Every antithrombotic requires prior investigation for high-risk lesions.
For organ-threatening ANCA vasculitis, rituximab or cyclophosphamide is combined with glucocorticoids according to guidelines; avacopan may reduce steroid exposure in selected patients. Coronary involvement has no validated separate regimen; systemic remission must be documented during follow-up. Eosinophilic myocarditis requires urgent assessment. Revascularization treats epicardial lesions, not myocardial infiltration.

IgG4-related disease is often initially treated with glucocorticoids; rituximab or other steroid-sparing drugs are considered for relapse, steroid dependence, or important organ involvement. Infection and cancer must be excluded before immunosuppression; established fibrosis responds less than cellular inflammation. Residual narrowing may require intervention. Serial imaging assesses perivascular mass and lumen.
PCI may rapidly restore flow, but active inflammation, fibrotic ostia, adjacent aneurysms, and thrombus increase restenosis and complications. IVUS or OCT helps choose diameter, landing zones, and strategy; imaging-guided PCI is particularly useful in atypical lesions. A covered stent may exclude selected aneurysms. Bifurcations and side branches may limit use.

Bypass is considered for left main disease, multivessel disease, ostial stenosis unsuitable for PCI, or complex aneurysms. Outcome depends on the distal bed and activity of the aorta used for anastomosis; elective surgery benefits from quiescent disease when achievable. Emergencies do not always permit waiting. Perioperative immunosuppression balances relapse and infection.
Antiplatelet drugs and anticoagulants do not treat inflammation and are not prescribed for vasculitis alone. They are indicated by stents, coronary syndrome, thrombus, high-risk aneurysm, or another specific condition, with particular caution in aneurysmal diseases; targeted thromboprophylaxis avoids dangerous generalization. Pulmonary aneurysms must be excluded in Behçet disease. Kawasaki regimens follow maximum and current size.

Prognosis varies enormously. Small Kawasaki aneurysms may remodel and carry low risk, whereas giant aneurysms retain lifelong risks of thrombosis and stenosis. Bilateral ostial lesions and vasculitic relapses increase risk; permanent follow-up is required in high-risk phenotypes. Control of cardiovascular factors remains indicated. No universal frequency applies to every vasculitis.

Complications

Aneurysmal dilation promotes stasis, mural thrombus, and progressive intraluminal organization. Thrombus may occlude the vessel or embolize distally, causing infarction even when external aneurysm diameter is unchanged; aneurysmal thrombosis is central in giant Kawasaki disease. Dehydration and prothrombotic states may raise risk. New pain requires urgent assessment, not simply intensifying treatment at home.
Fibroproliferative healing may produce critical stenosis, particularly at aneurysm entry or exit and ostia affected by aortitis. A long lesion may complicate PCI and surgery; scar stenosis may progress after inflammatory markers normalize. Ischemia tests define functional significance. Angiographic percentage alone does not describe all risk.

Coronary aneurysm rupture is rare but may cause hemopericardium, tamponade, fistula, or mediastinal hemorrhage. Risk is especially concerning in pseudoaneurysms and infected or rapidly growing lesions; rapid growth is a warning sign. Persistent pain and effusion require urgent imaging. Size, morphology, and cause guide intervention.
Myocardial infarction, repeated ischemia, and microembolization may leave scar, ventricular dysfunction, and ischemic mitral regurgitation. Extensive necrosis predisposes to pulmonary edema and cardiogenic shock; myocardial injury must be quantified by echocardiography and MRI. Heart failure treatment follows general evidence. Vasculitis control prevents new lesions but does not regenerate scar.

Acute ischemia or scar may cause ventricular tachycardia, ventricular fibrillation, and sudden death. Syncope with an aneurysm, ostial stenosis, or previous infarction requires monitoring and arrhythmic assessment; electrical risk depends on myocardial substrate. Defibrillator implantation follows standard cardiac indications, not vasculitis alone.
Procedures may be complicated by dissection, perforation, stent thrombosis, restenosis, side-branch occlusion, and anastomotic degeneration. Uncontrolled inflammation increases late failure in some vasculitides; procedural surveillance must include treated and untreated vessels. New symptoms do not always equal restenosis. Vasculitic relapse and structural progression must be distinguished.

Glucocorticoids and immunosuppressants increase the risk of infection, osteoporosis, diabetes, hypertension, cytopenias, infertility, and cancer according to drug and duration; these effects may indirectly increase cardiovascular risk and impair adherence; treatment toxicity requires prevention and monitoring. Cumulative steroid dose should be reduced when possible. Safety does not justify undertreating severe vasculitis.
The long-term problem is coexistence of relapsing inflammation, irreversible anatomical damage, and conventional atherosclerotic risk. Follow-up must integrate symptoms, vascular examination, biomarkers, targeted imaging, ventricular function, and drug safety; integrated assessment avoids undertreatment and unnecessary procedures. Every treatment change requires an explicit question. Prognosis improves when cardiology and rheumatology share care.

Pregnancy and the peripartum period require specific planning in women with giant aneurysms, critical stenoses, or anticoagulation. Circulating volume, heart rate, and coagulation change, while several immunosuppressants and antithrombotics have fetal or obstetric limitations; preconception counseling defines risk and compatible drugs. Unsupervised discontinuation risks thrombosis or relapse. Cardiology, rheumatology, and high-risk obstetrics coordinate care.