Author + information
- Robert Schueler, MD and
- Christoph Hammerstingl, MD∗ ()
- ↵∗Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany
We thank Dr. Ren and colleagues for the comment on our paper (1).
Iatrogenic atrial septal defect (iASD) sizes were considerably smaller in our study than Ren et al. (2) found in previous analyses of procedures using smaller transseptal sheaths. They found that iASDs <4 mm had no clinical significance. In our opinion, the cited studies are not comparable to our results due to the fact that we treated mainly typical heart failure patients with a significant proportion of patients with severely reduced left ventricular ejection fraction (LVEF). Assuming that in our cohort, left atrial pressures are significantly higher than in a healthier cohort, the hemodynamic consequences and persistence rates may differ significantly due to markedly increased shunt volumes. In fact, the hemodynamic relevance of ASD must not be calculated based only on the sheer and may have overestimated shunt sizes. Hemodynamic consequences are directly related to the associated shunt volumes, and high-flow shunts with small diameters can lead to significant volume overload.
We cannot follow the comment of Dr. Ren and colleagues We showed clearly a right-to-left shunting. In our opinion, it is not suitable to compare periprocedural intracardiac echocardiography with transesophageal echocardiography performed 6 months after transseptal puncture. We agree with Ren et al. that it is not clear whether iASD persistence accounts for adverse outcomes after MitraClip procedures or whether the persistence of an ASD just reflects adverse conditions, which lead to higher mortality and impaired functional outcomes.
The cited “discrepancies” between left ventricular end-diastolic and end-systolic volumes in patients with or without iASD were not statistically significant, and therefore, it is highly hypothetical to draw any conclusion from this finding, which might be due to play of chance in a small patient cohort. LVEF, derived from left ventricular end-diastolic and end-systolic volumes, was entered into regression analysis and failed to show significance for the prediction of 6-month mortality rates.
Most of all, the aim of our study was to assess the persistence rate of iASDs after MitraClip procedure and to report a possible influence on functional outcome. We did not aim to measure development of ASD sizes and echocardiographic flow features. We doubt the reliability of 2-dimensional echocardiography for sizing small iASDs occurring in mobile anatomical structures and echocardiography can only give us a rough estimate of the true ASD sizes. The hemodynamic consequences of ASDs should be determined with invasive measures as depicted by current guidelines (3,4).
We feel that our work contributes to a more careful evaluation of patients with persistent iASD after transseptal procedures, which might help lead to a better understanding and, in addition, to increased watchfulness regarding the clinical consequences of interatrial shunting in such patients.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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