Usefulness of transthoracic echocardiography to accurately diagnose recoarctation of the aorta after the Norwood procedure

Abstract

Recoarctation of the aorta (RCoA) is a major cause of morbidity and mortality after the Norwood procedure. We sought to identify transthoracic echocardiographic (TTE) indexes associated with RCoA and to develop a highly sensitive and specific diagnostic score for accurate diagnosis. All subjects who underwent a Norwood procedure from December 2005 to December 2009 were identified. Subjects were excluded if they did not undergo a TTE within 1 month of an outcome-defining event (cardiac catheterization, autopsy, or surgery). RCoA was defined as arch intervention at catheterization or surgery or findings of RCoA at autopsy. Of 113 subjects included for analysis, RCoA occurred in 19 (17%). All TTE indexes were significantly associated with RCoA in univariate testing. In the final multivariate model, peak isthmus velocity >2.5 m/s (p <0.001), coarctation index, defined as the ratio of the narrowest region of the descending thoracic aorta to the distal descending thoracic aorta diameter <0.7 (p <0.01), and decrease in ventricular systolic performance (p = 0.03) were all significantly associated with RCoA. A composite score was developed using a peak velocity of >2.5 m/s (2 points), coarctation index <0.7 (1 point), and a decrease in ventricular systolic performance (1 point). A score of ≥2 diagnosed RCoA with 100% sensitivity and 85% specificity. The score performed equally well regardless of shunt type. In conclusion, a composite score of TTE indexes accurately discriminates RCoA in patients who have undergone the Norwood procedure.