Characteristics of the Interatrial Communication in Patients Undergoing Transcatheter Device Closure of Atrial Septal Defects for Cryptogenic Stroke

Background: Prior studies suggest that patent foramen ovale (PFO) diameter >4 mm is associated with a high probability of cryptogenic ischemic stroke (CIS). Methods: We evaluated all patients diagnosed with CIS who underwent closure of intra-atrial communication (IAC) using the Amplatzer atrial septal defect (ASD) occluder in our institution between August 1997 and March 2004. For each IAC, echocardiographic diameters and balloon-stretched diameters were recorded. Stretchability index was calculated as the ratio of stretched diameter to unstretched diameter. Results: Fifty-six patients met the inclusion criteria for this study. There was an inverse logarithmic relationship between unstretched IAC diameter and stretchability index. For the 28 smaller defects, the median IAC diameter was 2 mm, and median stretchability index was 5.58 (range 2.6–15). For the 28 larger defects, median diameter was 6 mm, and median stretchability index was 2.38 (range 1.05–5). The difference in stretchability index between the two groups was significant (P < 0.0001). Conclusion: Our data bring into question the concept that the diameter of the defect would singularly predict the probability of stroke.