Stretched minimal diameter of the ductus and coil occlusion.

Abstract

Background: Stretching of the ductus was supposed to determine the size mismatch of the coil with the ductus in coil occlusion that results in residual leak or migration.

Methods: We measured the minimal diameter (D) and the stretched minimal diameter (S) of the ductus in 12 patients with patent ductus arteriosus (PDA). The stretch index (SI) was calculated as S divided by D. We calculated ratios of the loop diameter of the first implanted coil to D (C1/D) and S (C1/S) and those of the sum of all the loop diameters of all implanted coils for complete closure to D (total C/D) and to S (total C/S).

Results: Stretched minimal diameter divided by D was 1.8 +/- 0.3. Ratios of the loop diameter of the first implanted coil to D (C1/D), and S (C1/S) were 3.7 +/- 1.8 and 2.1 +/- 0.9, respectively. Ratios of the sum of all the loop diameters of all coils to D (total C/D) and S (total C/S) were 5.2 +/- 1.6 and 2.9 +/- 0.9, respectively. Standard deviations of C1/S and total C/S are significantly smaller than those of C1/D and total C/D, respectively.

Conclusions: The narrowest segment of the ductus could be stretched to twice the size of the minimal diameter. The stretched minimal diameter may be a more reliable parameter to select the loop diameter of coils than the angiographic minimal diameter.