Practice Patterns in the Management of Pressure Restrictive Perimembranous Ventricular Septal Defects: A Multinational Survey.

Indications for the closure of pressure restrictive perimembranous ventricular septal defects (pmVSD) are not well established in the pediatric population. We sought to assess practice variability among pediatric cardiologists in the United States (US), Canada, Australia, and New Zealand. A survey ascertaining practice patterns, including case vignettes with incremental progression of disease severity, was designed and administered through representative professional cardiac organizations and email listservs in the designated countries. Among the 299 respondents, 209 (70.0%) were from the US, 65 (21.7%) were from Canada and 25 (8.3%) were from Australia and New Zealand. Indications for pressure restrictive pmVSD closure included the presence of left ventricular (LV) dilation for 81.6% (244/299) (defined as z-score ≥ 2 for 59.0% (144/244) and ≥ 3 for 40.2% (98/244)) and significant pulmonary-systemic flow ratio (QP:QS) for 71.2% (213/299) [defined as ≥ 1.5:1 for 36.2% (77/213) and ≥ 2 for 62% (132/213)]. US pediatric cardiologists elected to close restrictive pmVSD at lower LV z-score and QP:QS ratio cut-offs (p-value 0.0002 and 0.013, respectively). In a case vignette, 63.6% (173/272) chose to intervene if there was right coronary cusp prolapse with stable mild aortic regurgitation. Of the remaining cardiologists, 93% (92/99) intervened if the aortic regurgitation was progressive (from trivial to mild). Commonly identified indications with variable thresholds for closure of pressure restrictive pmVSDs included the presence or progression of LV dilation, significant volume loading, and aortic valve prolapse with regurgitation. US pediatric cardiologists may have a lower threshold for pmVSD closure.