Persistence of iatrogenic atrial septal defect after pulmonary vein isolation--an underestimated risk?

BACKGROUND: According to present knowledge, pulmonary vein isolation (PVI) bears a low interventional risk and has a high feasibility. For completion of PVI, left atrial access is achieved via single or double transseptal puncture. We sought to determine the incidence and echocardiographic characteristics of persistent iatrogenic atrial septal defect (iASD) after PVI. Further objectives were to define clinical and periprocedural risk factors for the development of iASD. METHODS: Every patient admitted for PVI at our hospital was screened for eligibility for study participation. Exclusion criteria were inability for undergoing transesophageal echocardiography, preexisting atrial septal defect, open-heart surgery or another transseptal procedure during the follow-up period. Transesophageal echocardiography was performed before PVI and after 9 months. Interatrial shunt was characterized by echocardiographic parameters; right-to-left-shunting (RLS) was quantified by contrast echocardiography. RESULTS: Forty-two patients were included, 27 patients underwent PVI with single transseptal puncture and additional advancement of a second electrophysiologic catheter (group A) 15 patients underwent PVI with double transseptal puncture (group B). In 8 patients of group A, iASD persisted after the follow-up period, including 6 patients with distinct RLS. We saw no iASD in group B (P = .011, CI -0.79 to -0.11). Preprocedural pulmonary artery pressure was significantly higher in patients with iASD and accompanying RLS, compared with patients with iASD and no evidence of RLS (23.75 +/- 0.50 vs 17.59 +/- 5.82, P = .048, CI 0.048-12.27). CONCLUSION: This is the first study that demonstrates a high incidence of long-term persistent iatrogenic atrial septal defect with RLS after PVI. All interatrial shunts occurred after single transseptal puncture with passage of 2 electrophysiologic catheters into the left atrium. Increased preprocedural pulmonary artery pressure seems to promote the occurrence of RLS across iASD.

Persistence of iatrogenic atrial septal defect after interventional mitral valve repair with the MitraClip system: a note of caution.

OBJECTIVES: The purpose of this study was to investigate the persistence rates of iatrogenic atrial septal defect (iASD) after interventional edge-to-edge repair with serial transesophageal echocardiography examinations and close clinical follow-up (FU). BACKGROUND: Transcatheter mitral valve repair (TMVR) with the MitraClip system (Abbott Vascular, Abbott Park, Illinois) is a therapeutic alternative to surgery in selected high-risk patients. Clip placement requires interatrial transseptal puncture and meticulous manipulation of the steerable sheath. The persistence of iASD after MitraClip procedures and its clinical relevance is unknown. METHODS: A total of 66 patients (76.7% male, mean age 77.1 ± 7.9 years) with symptomatic mitral regurgitation (MR) at prohibitive surgical risk (EuroSCORE II 10.1 ± 6.1%) underwent MitraClip procedures and completed 6 months of FU. RESULTS: Transesophageal echocardiography after FU showed persistent iASD in 50% of cases. Patients with iASD did not significantly differ from patients without ASD concerning baseline characteristics, New York Heart Association functional class, severity of MR, and acute procedural success rates (p > 0.05). When comparing procedural details and hemodynamic measures between groups, MitraClip procedures took longer in patients without iASD (82.4 ± 39.7 min vs. 68.9 ± 45.5 min; p = 0.05), and echocardiography after FU showed less decrease of systolic pulmonary artery pressures in the iASD group (-1.6 ± 14.1 mm Hg vs. 9.3 ± 17.4 mm Hg; p = 0.02). Clinically, patients with iASD presented more often with New York Heart Association functional classes >II after FU (57% vs. 30%; p = 0.04), showed higher levels of N-terminal pro-brain natriuretic peptide (6,667.3 ± 7,363.9 ng/dl vs. 4,835.9 ± 6,681.7 ng/dl; p = 0.05), and had less improvement in 6-min walking distances (20.8 ± 107.4 m vs. 114.6 ± 116.4 m; p = 0.001). Patients with iASD showed higher death rates during 6 months (16.6% vs. 3.3%; p = 0.05). Cox regression analysis found that only persistence of iASD (p = 0.04) was associated with 6-month survival. CONCLUSIONS: The persistence rate of 50% iASD after MitraClip procedures is considerably high. Persistent interatrial shunting was associated with worse clinical outcomes and increased mortality. Further studies are warranted to investigate if persistent interatrial shunting is the mediator or marker of advanced disease in these patients.