What are the sites of vegetations in VSD with endocarditis?

What are the sites of vegetations in VSD with endocarditis?

Locations of vegetations in endocarditis depends on direction of the blood flow jet which causes jet lesions at the site at which it impinges, causing damage to the endothelium. It is at this region that small thrombi can form and become a nidus for vegetations. In ventricular septal defect (VSD), there is a left to right jet from the left ventricle to right ventricle. The smaller the size of the VSD, higher the pressure gradient between the two ventricles and greater the velocity of the jet and chance for jet lesion. For the same reason, endocarditis is more common in small VSD and rare in large VSD.
When there is a jet, there are also eddy currents generated on either sides of the jet which produces local stasis and allows the microbes to settle down. This is the explanation of vegetations occurring on the right ventricular side of the interventricular septum.

Depending on this hemodynamic explanation, the potential sites of vegetations in VSD with endocarditis are:

1. Right ventricular side of the interventricular septum
2. Septal leaflet of tricuspid valve
3. Right ventricular outflow tract (can produce pulmonary infarcts or multiple lung abscesses)
4. Pulmonary valve
5. Aortic valve – ventricular septal defects can be associated with aortic regurgitation and aortic valve endocarditis can occur

Reference

1. Shanthi C, Madathil RS, Saldanha R, Vakamudi M, Balakrishnan K. Ventricular septal defect complicated by infective endocarditis of the aortic valve causing severe aortic regurgitation: the role of aortic valve repair. J Heart Valve Dis. 2002 May;11(3):389-91.