“Twin Icicle” Calcifications Cause Aortic Annular Rupture

Aortic annular rupture is a potentially fatal complication after transcatheter aortic valve implantation with high mortality. Although it is quite rare and difficult to identify the mechanisms and predictors, prosthesis oversizing and massive calcification of the aortic annulus are thought to be a potential risk of this complication. A case presented here is an aortic annular rupture after transcatheter aortic valve implantation. Although the valve was not oversized, there were 2 severe calcifications of aortic annulus at nearby areas like “twin icicles,” thought to be a trigger of this potentially fatal complication. Aortic annular rupture is a potentially fatal complication after transcatheter aortic valve implantation with high mortality. Although it is quite rare and difficult to identify the mechanisms and predictors, prosthesis oversizing and massive calcification of the aortic annulus are thought to be a potential risk of this complication. A case presented here is an aortic annular rupture after transcatheter aortic valve implantation. Although the valve was not oversized, there were 2 severe calcifications of aortic annulus at nearby areas like “twin icicles,” thought to be a trigger of this potentially fatal complication. Aortic annular rupture is a potentially fatal complication after transcatheter aortic valve implantation (TAVI); however, identifying the causes and predictors is difficult because it is rare, with reports of up to 1.1% [1Barbanti M. Yang T.H. Rodes Cabau J. et al.Anatomical and procedural features associated with aortic root rupture during balloon-expandable transcatheter aortic valve replacement.Circulation. 2013; 128: 244-253Crossref PubMed Scopus (393) Google Scholar, 2Girdauskas E. Owais T. Fey B. et al.Subannular perforation of left ventricular outflow tract associated with transcatheter valve implantation: pathophysiological background and clinical implications.Eur J Cardiothorac Surg. 2017; 51: 91-96Crossref PubMed Scopus (22) Google Scholar]. The risk of annular rupture increases during TAVI due to device oversizing, which may be preferred to reduce the risk of paravalvular leak. Accurate preoperative assessment of the aortic annulus dimension is crucial for successful TAVI to avoid an incorrectly sized prosthesis resulting in catastrophic complications. When the size is too big, it might cause annular rupture and coronary arteries obstruction. In contrast, when the size is too small, it might cause prosthesis migration and severe paravalvular leakage. However, the incidence of annular rupture is not necessarily related to discrepancies between the annulus size and the bioprosthesis size. In addition, the predictors of this complication are difficult to identify due to its low frequency. A voluminous amount of calcification located in the aortic annulus is thought to be a potential risk of annular rupture [3Hayashida K. Bouvier E. Lefevre T. et al.Potential mechanism of annulus rupture during transcatheter aortic valve implantation.Catheter Cardiovasc Interv. 2013; 82: E742-E746Crossref PubMed Scopus (65) Google Scholar, 4Pasic M. Unbehaun A. Buz S. Drews T. Hetzer R. Annular rupture during transcatheter aortic valve replacement: classification, pathophysiology, diagnostics, treatment approaches, and prevention.JACC Cardiovasc Interv. 2015; 8: 1-9Crossref PubMed Scopus (119) Google Scholar]. In such a case, fatal aortic annular rupture may occur, even if the device is not oversized. A 75-year-old frail woman with reduced mobility and respiratory function because of bronchial asthma underwent TAVI for severe aortic stenosis using a balloon-expandable SAPIEN 3 valve (Edwards Lifesciences, Irvine, CA) through a transfemoral approach while under general anesthesia. Preoperative computed tomography (CT) revealed 2 severe annular calcifications extending into the left ventricular outflow tract (LVOT) around the non/left commissure, appearing as “twin icicles” (Fig 1A). These 2 calcifications extended into the LVOT toward the anterior leaflet of the mitral valve (Fig 1B). As revealed by CT scans, the aortic annular area was 358 mm2, and the mean annular diameter was 21.4 mm. Self-expandable valves were not indicated because of her small sinus of Valsalva. We therefore we selected a 23-mm SAPIEN 3 valve and planned to perform very slow inflation with a 1 mL reduced inflation volume (valve size/CT-measured aortic annular area = 1.06) to avoid aortic annular rupture. After deployment of the prosthesis as planned, additional balloon dilatation was required because of severe paravalvular leakage (Fig 2A). Although the leakage resolved after balloon dilatation with same inflation volume, cardiac tamponade occurred (Fig 2B). After immediate pericardial drainage, the hemodynamics became relatively stabilized. An emergency median sternotomy was performed, and cardiopulmonary bypass was established. Massive bleeding from the aortic root was found. With the patient under cardiac arrest, the implanted SAPIEN 3 valve was extracted, and the calcified native aortic valves were resected. We found rupture of the sinus of Valsalva and aortic annulus around the non/left commissure. The aortotomy was extended to the rupture site, and we performed surgical mechanical aortic valve replacement with repair of the annular rupture using a pericardial patch. The patient recovered uneventfully and was transferred to another hospital for rehabilitation 30 days after the operation. Annular rupture is one of the most severe complications of TAVI and occurs in approximately 1% of cases. Although occurring relatively rarely, it is associated with a high mortality rate with estimates ranging from 50% to 100%, even in recent series [1Barbanti M. Yang T.H. Rodes Cabau J. et al.Anatomical and procedural features associated with aortic root rupture during balloon-expandable transcatheter aortic valve replacement.Circulation. 2013; 128: 244-253Crossref PubMed Scopus (393) Google Scholar, 2Girdauskas E. Owais T. Fey B. et al.Subannular perforation of left ventricular outflow tract associated with transcatheter valve implantation: pathophysiological background and clinical implications.Eur J Cardiothorac Surg. 2017; 51: 91-96Crossref PubMed Scopus (22) Google Scholar, 5Eggebrecht H. Mehta R.H. Kahlert P. et al.Emergent cardiac surgery during transcatheter aortic valve implantation (TAVI): insights from the Edwards SAPIEN Aortic Bioprosthesis European Outcome (SOURCE) registry.EuroIntervention. 2014; 10: 975-981Crossref PubMed Scopus (28) Google Scholar]. The predictors and mechanisms of this complication remain unclear, however [2Girdauskas E. Owais T. Fey B. et al.Subannular perforation of left ventricular outflow tract associated with transcatheter valve implantation: pathophysiological background and clinical implications.Eur J Cardiothorac Surg. 2017; 51: 91-96Crossref PubMed Scopus (22) Google Scholar, 3Hayashida K. Bouvier E. Lefevre T. et al.Potential mechanism of annulus rupture during transcatheter aortic valve implantation.Catheter Cardiovasc Interv. 2013; 82: E742-E746Crossref PubMed Scopus (65) Google Scholar, 4Pasic M. Unbehaun A. Buz S. Drews T. Hetzer R. Annular rupture during transcatheter aortic valve replacement: classification, pathophysiology, diagnostics, treatment approaches, and prevention.JACC Cardiovasc Interv. 2015; 8: 1-9Crossref PubMed Scopus (119) Google Scholar]. Results of a 2-year follow-up of patients in the Placement of Aortic Transcatheter Valves (PARTNER) trial supported TAVI as an alternative to surgical valve replacement in high-risk patients [6Kodali S.K. Williams M.R. Smith C.R. et al.Two-year outcomes after transcatheter or surgical aortic-valve replacement.N Engl J Med. 2012; 366: 1686-1695Crossref PubMed Scopus (1908) Google Scholar]. TAVI and conventional aortic valve replacement were reported to have similar results with respect to mortality, reduction of symptoms, and improved valve hemodynamics; however, paravalvular regurgitation occurred more frequently after TAVI and was associated with increased late mortality [6Kodali S.K. Williams M.R. Smith C.R. et al.Two-year outcomes after transcatheter or surgical aortic-valve replacement.N Engl J Med. 2012; 366: 1686-1695Crossref PubMed Scopus (1908) Google Scholar]. An adequately sized valve and adequate inflation volume were therefore required for TAVI to avoid paravalvular leakage [6Kodali S.K. Williams M.R. Smith C.R. et al.Two-year outcomes after transcatheter or surgical aortic-valve replacement.N Engl J Med. 2012; 366: 1686-1695Crossref PubMed Scopus (1908) Google Scholar, 7Cerillo A.G. Mariani M. Berti S. Glauber M. Sizing the aortic annulus.Ann Cardiothorac Surg. 2012; 1: 245-256PubMed Google Scholar]. However, exact measurement of the oval-shaped annulus was difficult. The mismatch in size between the round-shaped prosthesis and the oval aortic annulus may therefore result in oversized prosthesis associated with a potential risk for aortic annular rupture during TAVI [8Lange R. Bleiziffer S. Piazza N. et al.Incidence and treatment of procedural cardiovascular complications associated with trans-arterial and trans-apical interventional aortic valve implantation in 412 consecutive patients.Eur J Cardiothorac Surg. 2011; 40: 1105-1113PubMed Google Scholar]. No instances of valve oversizing and inflation with additional volume occurred in our patient, in compliance with the historical criteria of the Edwards SAPIEN valve. Another potential risk factor for annular rupture was severe calcification of the aortic annulus, particularly a large calcification extending into the LVOT [2Girdauskas E. Owais T. Fey B. et al.Subannular perforation of left ventricular outflow tract associated with transcatheter valve implantation: pathophysiological background and clinical implications.Eur J Cardiothorac Surg. 2017; 51: 91-96Crossref PubMed Scopus (22) Google Scholar, 3Hayashida K. Bouvier E. Lefevre T. et al.Potential mechanism of annulus rupture during transcatheter aortic valve implantation.Catheter Cardiovasc Interv. 2013; 82: E742-E746Crossref PubMed Scopus (65) Google Scholar, 4Pasic M. Unbehaun A. Buz S. Drews T. Hetzer R. Annular rupture during transcatheter aortic valve replacement: classification, pathophysiology, diagnostics, treatment approaches, and prevention.JACC Cardiovasc Interv. 2015; 8: 1-9Crossref PubMed Scopus (119) Google Scholar]. If the calcification existed at only one portion, TAVI would not be a big problem. Even 2 calcifications existing apart from each other might not be a serious problem for TAVI. In our patient, 2 calcifications were near each other, like “twin icicles,” extending into the LVOT. The tissue between these calcifications was so fragile and weak that forceful expansion of a prosthesis could easily injure the vulnerable area. The annulus can rupture because of mechanical stress caused by forceful expansion of a balloon-expandable prosthesis, eventually leading to compression of the vulnerable area [1Barbanti M. Yang T.H. Rodes Cabau J. et al.Anatomical and procedural features associated with aortic root rupture during balloon-expandable transcatheter aortic valve replacement.Circulation. 2013; 128: 244-253Crossref PubMed Scopus (393) Google Scholar, 2Girdauskas E. Owais T. Fey B. et al.Subannular perforation of left ventricular outflow tract associated with transcatheter valve implantation: pathophysiological background and clinical implications.Eur J Cardiothorac Surg. 2017; 51: 91-96Crossref PubMed Scopus (22) Google Scholar, 3Hayashida K. Bouvier E. Lefevre T. et al.Potential mechanism of annulus rupture during transcatheter aortic valve implantation.Catheter Cardiovasc Interv. 2013; 82: E742-E746Crossref PubMed Scopus (65) Google Scholar, 4Pasic M. Unbehaun A. Buz S. Drews T. Hetzer R. Annular rupture during transcatheter aortic valve replacement: classification, pathophysiology, diagnostics, treatment approaches, and prevention.JACC Cardiovasc Interv. 2015; 8: 1-9Crossref PubMed Scopus (119) Google Scholar, 8Lange R. Bleiziffer S. Piazza N. et al.Incidence and treatment of procedural cardiovascular complications associated with trans-arterial and trans-apical interventional aortic valve implantation in 412 consecutive patients.Eur J Cardiothorac Surg. 2011; 40: 1105-1113PubMed Google Scholar]; therefore, use of a self-expandable valve may be safer in the presence of voluminous calcifications at the vulnerable area. In conclusion, annular rupture after TAVI is a rare and potentially fatal event. A voluminous amount of calcification at the aortic annulus extending into the LVOT may be a mechanism for such a severe complication. We must pay attention to the CT findings, including calcifications of the aortic annulus located at more than 2 nearby areas, like “twin icicles,” which may indicate a high risk factor for annular rupture.