Assessing the impact of residual coarctation of the aorta on renal perfusion

Despite the effectiveness of the surgical or percutaneous treatment of coarctation of the aorta, the presence of hypertension in these patients remains a common and concerning issue. This study was undertaken to explore the relation between the severity of coarctation of the aorta and renal perfusion and to evaluate the role of renal scintigraphy as a predictive tool for clinical outcomes after percutaneous treatment of coarctation of the aorta.

Adult patients with coarctation of the aorta and concomitant arterial hypertension were enrolled in the study. Ambulatory 24-hour blood pressure monitoring, CT angiography, and a renal perfusion scan were performed, along with invasive pressure gradient measurements. Patients with invasive peak gradients ≥20mmHg and/or a difference of ≥50% in diameter between the isthmus and the descending aorta at the diaphragmatic level were selected for percutaneous stent implantation.

The mean time to peak change in renal scintigraphy after captopril did not significantly differ between the Medical group (-1.01 ± 2.526 min. for the left kidney and -0.19 ± 1.46 min. for the right kidney) and the Stent group (-0.59 ± 1.188 min. for the left kidney and -0.17 ± 1.461 min. for the right kidney) (p-values > 0.05). No statistically significant changes in renal perfusion were observed between pre-and post-stent implantation measurements.

In this pilot study, no clear association was found between the degree of aortic narrowing and renal perfusion, and no measurable reduction in renal perfusion was detected. Stent implantation did not result in significant short-term changes in blood pressure. These findings are exploratory and require confirmation in larger studies.