What is the incidence of clinically significant coronary calcification in young adults (18‑30 years) with a history of Kawasaki disease, especially those with persistent large or giant aneurysms?

Incidence of Significant Coronary Calcification in Young Adults with Kawasaki Disease History

Young adults with a history of Kawasaki disease and persistent large or giant coronary aneurysms have an extremely high incidence of significant coronary calcification, approaching 80-95%, while those with normal coronary arteries during acute disease have essentially zero risk of calcification.

Incidence Based on Coronary Artery Status During Acute Phase

Patients with Giant or Persistent Aneurysms

• Approximately 79-95% of patients with coronary aneurysms develop detectable coronary artery calcification (CAC) when imaged ≥9 years after acute Kawasaki disease 1, 2
• In one cohort of 24 subjects with persistent coronary aneurysms (median age 19.5 years, median 15.1 years post-KD), 19 of 24 (79%) had detectable CAC, with median calcium volume of 542 mm³ (range 17-8,218 mm³) 1
• A separate study found that 10 of 14 patients (71%) with coronary aneurysms had coronary calcification when imaged at median 14.8 years post-acute illness 2
• All patients with coronary aneurysms associated with stenosis and/or occlusion had identifiable coronary calcification on plain chest X-ray 3

Patients with Normal or Transiently Dilated Coronaries

• Zero incidence: All 100 subjects with coronary arteries classified as normal during acute KD had zero CAC on follow-up imaging 1
• Near-zero incidence: Only 1 of 12 patients (8%) with transiently dilated coronaries during acute phase developed any calcification 2
• All 10 subjects with persistently dilated (but not aneurysmal) coronaries had zero CAC 1

Temporal Relationship and Severity

Timing of Calcification Development

• Coronary calcification occurs late in the disease course, typically many years after the acute illness 2
• The degree of coronary artery dilation after Kawasaki disease correlates with the risk of future calcification 4
• Calcification severity ranges from mild to severe, with some patients developing massive calcification (up to 8,218 mm³ calcium volume) 1

Clinical Significance of Calcification

• The presence of CAC is strongly associated with stenotic lesions: all significant stenotic lesions were concomitant with calcification 3
• Heavy calcification of the inner layer can prevent normal luminal development and produce significant narrowing (up to 50% stenosis) as patients grow into adulthood 5
• In a prospective cohort pilot study, patients with Kawasaki disease with residual coronary abnormalities showed CT evidence of CAC, and the presence of CAC may be predictive of sudden death 4

Diagnostic Performance of CAC Screening

Sensitivity and Specificity

• For subjects imaged ≥9 years after acute KD, CAC presence had 95% sensitivity and 100% specificity for detecting coronary artery abnormalities (defined as aneurysm and/or stenosis) 1
• Multislice spiral CT demonstrated 100% sensitivity for detecting coronary artery aneurysms and 87.5% sensitivity for significant stenoses/occlusions in adolescents and young adults with KD 6
• False-positive results occurred in 5 arteries due to severe calcification and in 2 due to cardiac motion artifact, yielding 92.5% specificity 6

Clinical Implications and Surveillance Strategy

Risk Stratification Algorithm

• Young adults (18-30 years) with documented giant aneurysms (≥8 mm) or persistent large aneurysms during acute KD should be assumed to have very high risk (approximately 80-95%) of significant coronary calcification 1, 2
• Those with Z-score ≥10 and absolute dimension ≥8 mm had 48% incidence of adverse outcomes (catheter intervention, MI, death) 4
• Patients with normal coronary arteries during acute phase can be reassured of essentially zero risk of late calcification 1, 2

Screening Recommendations

• Plain chest X-ray with specific search for coronary calcification is a simple, inexpensive, low-dose method that easily identifies KD patients at risk for serious coronary stenosis 3
• When calcification is detected on chest X-ray, closer tracking of coronary artery patency is warranted via other imaging techniques 3
• CAC scanning may be a useful tool to screen patients with remote history of KD or suspected KD with unknown coronary artery status 1, 2

Management of Detected Calcification

• The presence of coronary calcification in young adults with KD history indicates high risk for progressive stenotic lesions and warrants aggressive surveillance 4
• Coronary calcification presents particular challenges for acute percutaneous interventions, relating to potential underestimation of true luminal dimensions and difficulty with stent deployment 4
• IVUS imaging is essential to demonstrate true luminal dimensions and improve stent deployment in these patients 4

Common Pitfalls to Avoid

• Do not assume that absence of symptoms indicates absence of significant coronary disease: MI in young KD patients can be clinically silent or present with atypical symptoms 4
• Do not rely solely on angiographic "normalization": vessels that appear angiographically normal after aneurysm regression may have significant wall thickening, calcification, and functional abnormalities on IVUS 4
• Do not underestimate stenosis severity in heavily calcified vessels: poor image quality and severe calcifications can lead to overestimation or underestimation of stenosis severity on coronary CTA 7
• Do not delay evaluation in patients with giant aneurysms: the highest risk of MI occurs in patients with giant aneurysms (≥8 mm), and serial stress tests with myocardial imaging are mandatory 4