Intravenous digital subtraction angiography in the pre-operative evaluation of coarctation of the thoracic aorta.

Many authors have previously advocated the use of intravenous digital subtraction angiography (IV-DSA) in the pre-operative evaluation of coarctation of aorta with excellent results and good surgical correlation. We have studied 20 patients with coarctation of aorta by IV-DSA and compared the angiographic findings with those seen at surgery in nine patients. The IV-DSA examinations were performed by utilizing small-volume (25 ml), bolus injections of an ionic, iodinated water soluble contrast medium delivered in the mid-right atrium. Good quality diagnostic arterial images were obtained in 14 patients (70 per cent). Associated cardiac decompensation and inability to profile the coarct segment due to overlap by surrounding dilated blood vessels were responsible for the unsuccessful examinations. Whereas most IV-DSA findings were confirmed at surgery, the calibre and length of the coarct segment at IV-DSA were found to be unreliable predictors of the actual severity of the coarctation. The IV-DSA images failed to detect a localized diaphragm at the coarct site in two patients. Even though IV-DSA is useful for the diagnosis of aortic coarctation, the surgeon must be aware of its pitfalls in assessing the calibre and length of the coarct segment.