Which of the following statements about VSD is/are correct?

B. Large VSDs associated with high pulmonary blood flow result in an enlarged left atrium on chest x-ray.

C. Patients with small (restrictive) VSDs tend to have normal right ventricular and pulmonary arterial pressures with normal pulmonary vascular resistance and no evidence of pulmonary vascular disease.

D. A pulmonary vascular resistance greater than 10 to 12 units per sq. m. is considered a contraindication to operation.

DISCUSSION: A large VSD is approximately the size of the aortic valve orifice or larger and causes systemic right ventricular systolic pressures. In the absence of right ventricular outflow tract obstruction, the pulmonary artery systolic pressure will also be systemic in the presence of a large VSD. Large VSDs associated with a high pulmonary blood flow do result in an enlarged left atrium because of increased pulmonary venous return. When marked enlargement of the left atrium is present in a patient suspected of having a VSD, the presence of coexisting mitral valve regurgitation should also be considered. Patients with small VSDs do have normal right ventricular and pulmonary arterial pressures. There is only a slight elevation of pulmonary blood flow relative to the systemic flow, and the pulmonary vascular resistance is normal without evidence of pulmonary vascular disease. At any age, the presence of pulmonary vascular disease so severe that the pulmonary vascular resistance is fixed and greater than 10 to 12 units per sq. m. is considered a contraindication to operation.