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A 6-year-old boy with a known ventricular septal defect is asymptomatic and has normal growth. On examination, there is a harsh pansystolic murmur at the left lower sternal border. A new high-pitched early diastolic murmur is also heard along the left sternal border. Echocardiography shows a supracristal (outlet) VSD with prolapse of the right coronary cusp of the aortic valve.
Which of the following is the most likely complication?
A. Aortic regurgitation
B. Complete heart block
C. Infective endocarditis
D. Pulmonary hypertension
E. Right ventricular outflow obstruction
Correct answer & Explanation
Answer: A. Aortic regurgitation
Explanation
A supracristal (outlet) VSD is particularly associated with aortic cusp prolapse and progressive aortic regurgitation. The abnormal flow through the VSD can draw the aortic cusp into the defect, causing progressive cusp distortion and incompetence. The right coronary cusp is most commonly affected.
The new early diastolic murmur is an important clinical clue to aortic regurgitation.
Why the other options are incorrect
- B. Complete heart block: Can occur following VSD surgery or device closure, but is not the characteristic complication of a supracristal VSD with aortic cusp prolapse.
- C. Infective endocarditis: VSDs can be associated with infective endocarditis, but the clinical finding of aortic cusp prolapse with an early diastolic murmur specifically indicates aortic regurgitation.
- D. Pulmonary hypertension: Usually results from a significant, longstanding left-to-right shunt rather than a small VSD complicated by aortic cusp prolapse.
- E. Right ventricular outflow obstruction: Not the characteristic complication of a supracristal VSD.
Exam clue
Supracristal VSD + aortic cusp prolapse + early diastolic murmur → aortic regurgitation.
Reference:
Kliegman RM, St Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 22nd ed. Elsevier. Chapter on Ventricular Septal Defect.
