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Successful surgical aortic valve replacement for prosthetic valve infective endocarditis following transcatheter aortic valve implantation
Journal of Cardiology Cases 12 (2015) 20–22
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
Successful surgical aortic valve replacement for prosthetic valve infective endocarditis following transcatheter aortic valve implantation Shinya Takimoto (MD)a, Kenji Minakata (MD)a,*, Kazuhiro Yamazaki (MD)a, Shingo Hirao (MD)a, Kentaro Watanabe (MD)a, Naritatsu Saito (MD)b, Masao Imai (MD)b, Shin Watanabe (MD)b, Hirotoshi Watanabe (MD)b, Hiroki Daijo (MD)c, Takeshi Kimura (MD, FJCC)b, Ryuzo Sakata (MD, FJCC)a a b c
Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Cardiology, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Anesthesiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 19 January 2015 Received in revised form 23 March 2015 Accepted 31 March 2015
An 80-year-old male underwent a transcatheter aortic valve implantation (TAVI) for severe senile aortic stenosis. Six weeks after the surgery, he was readmitted to our institution because of a high-grade fever. Transesophageal echocardiography revealed thickening of all three leaflets of the aortic prosthesis and mobile mass on the leaflet, and Streptococcus sanguis was identified from his blood culture. Therefore, he was diagnosed with prosthetic valve endocarditis (PVE) and received intensive intravenous antibiotic therapy. Because he did not respond to the pharmacological therapy, surgical aortic valve replacement (AVR) was indicated although it was considered a relatively high-risk procedure. Herein, we report on the successful surgical AVR in this patient using a pericardial valve after removal of the infected prosthetic valve, and discuss some issues related to this rare complication after TAVI. ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Keywords: Prosthetic valve endocarditis Surgical aortic valve replacement Transcatheter aortic valve implantation
Introduction Recently in Japan, transcatheter aortic valve implantation (TAVI) has become available for patients with severe aortic stenosis who are deemed inoperable or who have too high risk for conventional surgical aortic valve replacement (AVR). TAVI is a minimally invasive procedure in which surgical incisions are limited and cardiopulmonary bypass is usually unnecessary. Furthermore, because it can be performed quickly, the patients have less chance of surgically-related bacteremia causing prosthetic valve endocarditis
* Corresponding author at: Department of Cardiovascular Surgery, Kyoto University Hospital, 54 Kawaharacho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. Tel.: +81 75 751 3780; fax: +81 75 751 3098. E-mail address: [email protected] (K. Minakata).
(PVE) soon after the operation. In fact, it is known that PVE after TAVI is rare. We experienced a case of TAVI complicated with early postprocedural PVE, which subsequently required surgical AVR. Case report An 80-year-old male presented for elective TAVI for symptomatic severe aortic stenosis. Preoperative transthoracic echocardiography (TTE) demonstrated severe, tricuspid, and calcified aortic stenosis with a peak transvalvular pressure gradient of 108 mmHg (mean 64 mmHg) and a calculated aortic valve area of 0.86 cm2. In addition, he had multiple co-morbidities including chronic kidney disease (estimated glomerular filtration ratio: 33.9 mL/min/1.73 m2), and a remote history of cerebral infarction, bronchial asthma, hypertension, and prostatic cancer. Since preoperative coronary angiography showed severe stenosis of
http://dx.doi.org/10.1016/j.jccase.2015.03.012 1878-5409/ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
S. Takimoto et al. / Journal of Cardiology Cases 12 (2015) 20–22
Fig. 1.
21
Transthoracic echocardiography long-axis view. Masses were identified attached to the prosthetic valve leaflets.
the left anterior descending artery, percutaneous coronary intervention to the proximal left anterior descending artery was performed [1]. Although the predicted operative mortality was 2.98% according to the Society of Thoracic Surgeon’s risk score, he was deemed at high risk for surgical AVR because of the aforementioned multiple co-morbidities in addition to his severe dementia. However, he was considered to be a relatively good candidate for TAVI by our heart team. Thus, we performed a TAVI with a transfemoral approach using a 26 mm Edwards Sapien XT valve (Edwards Lifesciences, Irvine, CA, USA). His postoperative course was uneventful except for the fact that he required permanent pacemaker implantation on the 11th postoperative day because he had persistent complete atrio-ventricular block. Post-TAVI echocardiography demonstrated only trivial paravalvular aortic regurgitation with excellent prosthetic valve function. Thereafter, he was discharged. Two weeks after discharge, the patient presented at a local clinic with a high-grade fever and loss of appetite. He was initially diagnosed with a urinary tract infection, and given oral antibiotics for two weeks. In spite of this medication, he continued to have fever and was readmitted to our hospital. Laboratory results showed a slightly elevated white blood cell count (10,580/mL) and elevated C-reactive protein (CRP) of 9.1 mg/dL. Transesophageal echocardiography (TEE) demonstrated thickening of all three leaflets of the aortic prosthesis and medium-sized mobile mass on the aortic side of two of the three leaflets (6–9 mm; Fig. 1). The degree of paravalvular leakage remained the same, defined as only trivial. There were no findings of aortic root abscess. A diagnosis of early PVE was made, and treatment with empirical antibacterial therapy (vancomycin 1 g every 24 h and ampicillin 1 g every 12 h, intravenously) was initiated. After Streptococcus sanguis was identified from his blood culture, his antibiotics regimen was changed to continuous infusion of penicillin G (15 million units/24 h, intravenous continuously) and gentamycin (60 mg every 12 h, intravenously). This regimen was switched to ceftriaxone (1 g every 12 h) because the patient developed kidney dysfunction (serum creatinine of 3.0 mg/mL). His serum creatinine gradually improved
down to 1.3 mg/mL thereafter. Subsequently, oral screening revealed six dental caries, and all the affected teeth were extracted. In addition, brain magnetic resonance imaging demonstrated new acute cerebral infarction in the bilateral frontal lobes and lateral lobes, although the patient was totally neurologically intact. Furthermore, repeated TTE detected a large-sized mass on a native mitral valve leaflet in addition to those on the aortic prosthetic valve. After 4 weeks of the intensive antibiotic therapy, we decided to perform surgical AVR for refractory PVE. Under standard cardiopulmonary bypass with ascending aortic and bicaval cannulations, we removed the previous prosthesis (Fig. 2) and the retracted native calcified aortic cusps, and performed AVR with a bovine pericardial tissue valve (Carpentier Edwards Perimount bioprosthesis 21 mm). We also performed a vegetectomy of the mitral leaflet. Total cardiopulmonary bypass and aortic cross clamp times
Fig. 2.
Infected prosthesis explanted during the operation. A large-sized mass was seen attached to the aortic surface on one of the leaflets.
22
S. Takimoto et al. / Journal of Cardiology Cases 12 (2015) 20–22
were 119 and 87 min, respectively. He was maintained on an antibiotic therapy of ceftriaxone (1 g every 12 h) for another 4 weeks. His postoperative course was uneventful and he was discharged free of antibiotics.
In conclusion, PVE early after TAVI is rare. However, when it does occur, it usually requires the surgical removal of the infected prosthesis and AVR. Although the causes of PVE vary, our case suggests the importance of preoperative dental screening and care in patients undergoing TAVI.
Discussion Conflict of interest Since TAVI was first successfully performed by Cribier in 2002 [2], the number of patients with severe aortic stenosis treated with TAVI continues to increase. PVE after TAVI is relatively rare because TAVI usually does not require cardiopulmonary bypass, requires minimal skin incision, and can be done quickly. However, a few such cases have been reported because of the sheer number of TAVIs being performed worldwide [3–7]. The incidence of PVE after TAVI ranges from 0% to 2.3% in previous reports [4]. Loverix et al. reported a pooled analysis in patients with PVE after TAVI (n = 29), where blood culture was negative in 12 out of 29 cases (41.4%) and Enterococcus faecalis was the most common microorganism (27.6%) [3]. The causes of PVE included other infections, previous endoscopic procedures, prosthesis misplacement in the outflow tract of the left ventricle, and dental procedures without antibiotic prophylaxis. Eight patients underwent surgical AVR and the remaining patients were treated conservatively with antibiotics. The overall 30-day mortality was 22.3%. PVE is a rare but serious complication after TAVI, and it entails high morbidity and mortality. In general, it is difficult to treat PVE pharmacologically and it usually requires surgical intervention as the definitive treatment. Given the fact that many patients undergo TAVI because they are at too high risk to undergo conventional AVR, the risk posed by AVR for patients in this subgroup who suffer from PVE is even greater. In addition, AVR may not be indicated in some patients with PVE who are deemed inoperable. Therefore, the prevention of PVE is an extremely pressing issue. In the current case, the PVE was presumably caused by untreated dental caries without appropriate antibiotic therapy. It should be noted that preoperative dental screening is important for patients undergoing not only AVR but even TAVI. Needless to say, it is also crucial to maintain strict sterile conditions during the TAVI procedure and an appropriate antibiotic prophylaxis is essential postoperatively [8]. According to the PARTNER trial [9], although paravalvular leakage was much more common after TAVI than AVR, there were no differences in the incidence of PVE between TAVI and AVR at 2-year follow-up. However, the patients, especially who developed significant paravalvular leakage after TAVI, should be closely monitored because it is well known that paravalvular leakage is one of the most important risk factors for PVE.
We received no financial support and none of the authors had any conflicts on interest in regard to this report. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jccase.2015.03. 012. References [1] Kobayashi J. Changing strategy for aortic stenosis with coronary artery disease by transcatheter aortic valve implantation. Gen Thorac Cardiovasc Surg 2013;61:663–8. [2] Cribier A, Eltchaninoff H, Bash A, Borenstein N, Tron C, Bauer F, Derumeaux G, Anselme F, Laborde F, Leon MB. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation 2002;106:3006–8. [3] Loverix L, Juvonen T, Biancari F. Prosthesis endocarditis after transcatheter aortic valve implantation: pooled individual patient outcome. Int J Cardiol 2015;178:67–8. [4] Eisen A, Shapira Y, Sagie A, Kornowski R. Infective endocarditis in the transcatheter aortic valve replacement era: comprehensive review of a rare complication. Clin Cardiol 2012;35:E1–5. [5] Carnero-Alcazar M, Maroto Castellanos LC, Carnicer JC, Rodriguez Hernandez JE. Transapical aortic valve prosthetic endocarditis. Interact Cardiovasc Thorac Surg 2010;11:252–3. [6] Loverix L, Timmermans P, Benit E. Successful non-surgical treatment of endocarditis caused by Staphylococcus haemolyticus following transcatheter aortic valve implantation (TAVI). Acta Clin Belg 2013;68:376–9. [7] Loh PH, Bundgaard H, Sondergaard L. Infective endocarditis following transcatheter aortic valve replacement: diagnostic and management challenges. Catheter Cardiovasc Interv 2013;81:623–7. [8] Habib G, Hoen B, Tornos P, Thuny F, Prendergast B, Vilacosta I, Moreillon P, de Jesus Antunes M, Thilen U, Lekakis J, Lengyel M, Muller L, Naber CK, Nihoyannopoulos P, Moritz A, et al. Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009): The Task Force on the Prevention, Diagnosis, and Treatment of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and the International Society of Chemotherapy (ISC) for Infection and Cancer. Eur Heart J 2009;30: 2369–413. [9] Kodali SK, Williams MR, Smith CR, Svensson LG, Webb JG, Makkar RR, Fontana GP, Dewey TM, Thourani VH, Pichard AD, Fischbein M, Szeto WY, Lim S, Greason KL, Teirstein PS, et al. Two-year outcomes after transcatheter or surgical aorticvalve replacement. N Engl J Med 2012;366:1686–95.
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
Successful surgical aortic valve replacement for prosthetic valve infective endocarditis following transcatheter aortic valve implantation Shinya Takimoto (MD)a, Kenji Minakata (MD)a,*, Kazuhiro Yamazaki (MD)a, Shingo Hirao (MD)a, Kentaro Watanabe (MD)a, Naritatsu Saito (MD)b, Masao Imai (MD)b, Shin Watanabe (MD)b, Hirotoshi Watanabe (MD)b, Hiroki Daijo (MD)c, Takeshi Kimura (MD, FJCC)b, Ryuzo Sakata (MD, FJCC)a a b c
Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Cardiology, Kyoto University Graduate School of Medicine, Kyoto, Japan Department of Anesthesiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 19 January 2015 Received in revised form 23 March 2015 Accepted 31 March 2015
An 80-year-old male underwent a transcatheter aortic valve implantation (TAVI) for severe senile aortic stenosis. Six weeks after the surgery, he was readmitted to our institution because of a high-grade fever. Transesophageal echocardiography revealed thickening of all three leaflets of the aortic prosthesis and mobile mass on the leaflet, and Streptococcus sanguis was identified from his blood culture. Therefore, he was diagnosed with prosthetic valve endocarditis (PVE) and received intensive intravenous antibiotic therapy. Because he did not respond to the pharmacological therapy, surgical aortic valve replacement (AVR) was indicated although it was considered a relatively high-risk procedure. Herein, we report on the successful surgical AVR in this patient using a pericardial valve after removal of the infected prosthetic valve, and discuss some issues related to this rare complication after TAVI.
Keywords: Prosthetic valve endocarditis Surgical aortic valve replacement Transcatheter aortic valve implantation
Introduction Recently in Japan, transcatheter aortic valve implantation (TAVI) has become available for patients with severe aortic stenosis who are deemed inoperable or who have too high risk for conventional surgical aortic valve replacement (AVR). TAVI is a minimally invasive procedure in which surgical incisions are limited and cardiopulmonary bypass is usually unnecessary. Furthermore, because it can be performed quickly, the patients have less chance of surgically-related bacteremia causing prosthetic valve endocarditis
* Corresponding author at: Department of Cardiovascular Surgery, Kyoto University Hospital, 54 Kawaharacho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. Tel.: +81 75 751 3780; fax: +81 75 751 3098. E-mail address: [email protected] (K. Minakata).
(PVE) soon after the operation. In fact, it is known that PVE after TAVI is rare. We experienced a case of TAVI complicated with early postprocedural PVE, which subsequently required surgical AVR. Case report An 80-year-old male presented for elective TAVI for symptomatic severe aortic stenosis. Preoperative transthoracic echocardiography (TTE) demonstrated severe, tricuspid, and calcified aortic stenosis with a peak transvalvular pressure gradient of 108 mmHg (mean 64 mmHg) and a calculated aortic valve area of 0.86 cm2. In addition, he had multiple co-morbidities including chronic kidney disease (estimated glomerular filtration ratio: 33.9 mL/min/1.73 m2), and a remote history of cerebral infarction, bronchial asthma, hypertension, and prostatic cancer. Since preoperative coronary angiography showed severe stenosis of
http://dx.doi.org/10.1016/j.jccase.2015.03.012 1878-5409/ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
S. Takimoto et al. / Journal of Cardiology Cases 12 (2015) 20–22
Fig. 1.
21
Transthoracic echocardiography long-axis view. Masses were identified attached to the prosthetic valve leaflets.
the left anterior descending artery, percutaneous coronary intervention to the proximal left anterior descending artery was performed [1]. Although the predicted operative mortality was 2.98% according to the Society of Thoracic Surgeon’s risk score, he was deemed at high risk for surgical AVR because of the aforementioned multiple co-morbidities in addition to his severe dementia. However, he was considered to be a relatively good candidate for TAVI by our heart team. Thus, we performed a TAVI with a transfemoral approach using a 26 mm Edwards Sapien XT valve (Edwards Lifesciences, Irvine, CA, USA). His postoperative course was uneventful except for the fact that he required permanent pacemaker implantation on the 11th postoperative day because he had persistent complete atrio-ventricular block. Post-TAVI echocardiography demonstrated only trivial paravalvular aortic regurgitation with excellent prosthetic valve function. Thereafter, he was discharged. Two weeks after discharge, the patient presented at a local clinic with a high-grade fever and loss of appetite. He was initially diagnosed with a urinary tract infection, and given oral antibiotics for two weeks. In spite of this medication, he continued to have fever and was readmitted to our hospital. Laboratory results showed a slightly elevated white blood cell count (10,580/mL) and elevated C-reactive protein (CRP) of 9.1 mg/dL. Transesophageal echocardiography (TEE) demonstrated thickening of all three leaflets of the aortic prosthesis and medium-sized mobile mass on the aortic side of two of the three leaflets (6–9 mm; Fig. 1). The degree of paravalvular leakage remained the same, defined as only trivial. There were no findings of aortic root abscess. A diagnosis of early PVE was made, and treatment with empirical antibacterial therapy (vancomycin 1 g every 24 h and ampicillin 1 g every 12 h, intravenously) was initiated. After Streptococcus sanguis was identified from his blood culture, his antibiotics regimen was changed to continuous infusion of penicillin G (15 million units/24 h, intravenous continuously) and gentamycin (60 mg every 12 h, intravenously). This regimen was switched to ceftriaxone (1 g every 12 h) because the patient developed kidney dysfunction (serum creatinine of 3.0 mg/mL). His serum creatinine gradually improved
down to 1.3 mg/mL thereafter. Subsequently, oral screening revealed six dental caries, and all the affected teeth were extracted. In addition, brain magnetic resonance imaging demonstrated new acute cerebral infarction in the bilateral frontal lobes and lateral lobes, although the patient was totally neurologically intact. Furthermore, repeated TTE detected a large-sized mass on a native mitral valve leaflet in addition to those on the aortic prosthetic valve. After 4 weeks of the intensive antibiotic therapy, we decided to perform surgical AVR for refractory PVE. Under standard cardiopulmonary bypass with ascending aortic and bicaval cannulations, we removed the previous prosthesis (Fig. 2) and the retracted native calcified aortic cusps, and performed AVR with a bovine pericardial tissue valve (Carpentier Edwards Perimount bioprosthesis 21 mm). We also performed a vegetectomy of the mitral leaflet. Total cardiopulmonary bypass and aortic cross clamp times
Fig. 2.
Infected prosthesis explanted during the operation. A large-sized mass was seen attached to the aortic surface on one of the leaflets.
22
S. Takimoto et al. / Journal of Cardiology Cases 12 (2015) 20–22
were 119 and 87 min, respectively. He was maintained on an antibiotic therapy of ceftriaxone (1 g every 12 h) for another 4 weeks. His postoperative course was uneventful and he was discharged free of antibiotics.
In conclusion, PVE early after TAVI is rare. However, when it does occur, it usually requires the surgical removal of the infected prosthesis and AVR. Although the causes of PVE vary, our case suggests the importance of preoperative dental screening and care in patients undergoing TAVI.
Discussion Conflict of interest Since TAVI was first successfully performed by Cribier in 2002 [2], the number of patients with severe aortic stenosis treated with TAVI continues to increase. PVE after TAVI is relatively rare because TAVI usually does not require cardiopulmonary bypass, requires minimal skin incision, and can be done quickly. However, a few such cases have been reported because of the sheer number of TAVIs being performed worldwide [3–7]. The incidence of PVE after TAVI ranges from 0% to 2.3% in previous reports [4]. Loverix et al. reported a pooled analysis in patients with PVE after TAVI (n = 29), where blood culture was negative in 12 out of 29 cases (41.4%) and Enterococcus faecalis was the most common microorganism (27.6%) [3]. The causes of PVE included other infections, previous endoscopic procedures, prosthesis misplacement in the outflow tract of the left ventricle, and dental procedures without antibiotic prophylaxis. Eight patients underwent surgical AVR and the remaining patients were treated conservatively with antibiotics. The overall 30-day mortality was 22.3%. PVE is a rare but serious complication after TAVI, and it entails high morbidity and mortality. In general, it is difficult to treat PVE pharmacologically and it usually requires surgical intervention as the definitive treatment. Given the fact that many patients undergo TAVI because they are at too high risk to undergo conventional AVR, the risk posed by AVR for patients in this subgroup who suffer from PVE is even greater. In addition, AVR may not be indicated in some patients with PVE who are deemed inoperable. Therefore, the prevention of PVE is an extremely pressing issue. In the current case, the PVE was presumably caused by untreated dental caries without appropriate antibiotic therapy. It should be noted that preoperative dental screening is important for patients undergoing not only AVR but even TAVI. Needless to say, it is also crucial to maintain strict sterile conditions during the TAVI procedure and an appropriate antibiotic prophylaxis is essential postoperatively [8]. According to the PARTNER trial [9], although paravalvular leakage was much more common after TAVI than AVR, there were no differences in the incidence of PVE between TAVI and AVR at 2-year follow-up. However, the patients, especially who developed significant paravalvular leakage after TAVI, should be closely monitored because it is well known that paravalvular leakage is one of the most important risk factors for PVE.
We received no financial support and none of the authors had any conflicts on interest in regard to this report. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jccase.2015.03. 012. References [1] Kobayashi J. Changing strategy for aortic stenosis with coronary artery disease by transcatheter aortic valve implantation. Gen Thorac Cardiovasc Surg 2013;61:663–8. [2] Cribier A, Eltchaninoff H, Bash A, Borenstein N, Tron C, Bauer F, Derumeaux G, Anselme F, Laborde F, Leon MB. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation 2002;106:3006–8. [3] Loverix L, Juvonen T, Biancari F. Prosthesis endocarditis after transcatheter aortic valve implantation: pooled individual patient outcome. Int J Cardiol 2015;178:67–8. [4] Eisen A, Shapira Y, Sagie A, Kornowski R. Infective endocarditis in the transcatheter aortic valve replacement era: comprehensive review of a rare complication. Clin Cardiol 2012;35:E1–5. [5] Carnero-Alcazar M, Maroto Castellanos LC, Carnicer JC, Rodriguez Hernandez JE. Transapical aortic valve prosthetic endocarditis. Interact Cardiovasc Thorac Surg 2010;11:252–3. [6] Loverix L, Timmermans P, Benit E. Successful non-surgical treatment of endocarditis caused by Staphylococcus haemolyticus following transcatheter aortic valve implantation (TAVI). Acta Clin Belg 2013;68:376–9. [7] Loh PH, Bundgaard H, Sondergaard L. Infective endocarditis following transcatheter aortic valve replacement: diagnostic and management challenges. Catheter Cardiovasc Interv 2013;81:623–7. [8] Habib G, Hoen B, Tornos P, Thuny F, Prendergast B, Vilacosta I, Moreillon P, de Jesus Antunes M, Thilen U, Lekakis J, Lengyel M, Muller L, Naber CK, Nihoyannopoulos P, Moritz A, et al. Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009): The Task Force on the Prevention, Diagnosis, and Treatment of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and the International Society of Chemotherapy (ISC) for Infection and Cancer. Eur Heart J 2009;30: 2369–413. [9] Kodali SK, Williams MR, Smith CR, Svensson LG, Webb JG, Makkar RR, Fontana GP, Dewey TM, Thourani VH, Pichard AD, Fischbein M, Szeto WY, Lim S, Greason KL, Teirstein PS, et al. Two-year outcomes after transcatheter or surgical aorticvalve replacement. N Engl J Med 2012;366:1686–95.