Surg Today DOI 10.1007/s00595-014-0844-1
CASE REPORT
Quadricuspid aortic valve complicated with infective endocarditis: report of a case Hiroki Mizoguchi • Masayuki Sakaki • Kazushige Inoue • Yasuhiko Kobayashi • Takashi Iwata • Yasuo Suehiro • Takuya Miura
Received: 26 January 2013 / Accepted: 5 August 2013 Ó Springer Japan 2014
Abstract Congenital quadricuspid aortic valve is a rare cardiac malformation with an unknown risk of infective endocarditis. We report a case of quadricuspid aortic valve complicated with infective endocarditis. A 53-year-old Japanese woman was hospitalized with leg edema and a fever of unknown origin. Corynebacterium striatum was detected in the blood culture. Echocardiography demonstrated a quadricuspid aortic valve with vegetation and severe functional regurgitation. The condition was diagnosed as a quadricuspid aortic valve with infective endocarditis, for which surgery was performed. The quadricuspid aortic valve had three equal-sized cusps and one smaller cusp (type B according to Hurwitz classification). We dissected the vegetation and infectious focus and implanted a mechanical valve. Following the case report, we review the literature. Keywords Quadricuspid aortic valve Infective endocarditis Vegetation Aortic regurgitation Aortic valve replacement
Introduction Congenital quadricuspid aortic valve is a rare cardiac malformation with an unknown risk of infective endocarditis. We report an extremely rare case of quadricuspid aortic valve complicated with infective endocarditis, followed by a review of the literature.
H. Mizoguchi (&) M. Sakaki K. Inoue Y. Kobayashi T. Iwata Y. Suehiro T. Miura Department of Cardiovascular Surgery, Kansai Rosai Hospital, 3-1-69 Inabasou, Amagasaki, Hyogo 660-8511, Japan e-mail: [email protected]
Case report A 53-year-old Japanese woman was hospitalized for investigation of leg edema and a fever of unknown origin. She had a high-grade fever 5 months previously. The patient had not received dental treatment or steroid therapy and had no history of rheumatic fever or heart disease. At presentation, her temperature was 38.3 °C and her blood pressure was 108/55 mmHg, with a regular pulse rate of 62 beats/min. A grade 4/6 cardiac systolic ejection murmur was audible in the fourth intercostal space at the left sternal border. Laboratory tests showed anemia (hemoglobin level, 4.1 g/dL) and renal failure (creatinine level, 2.13 mg/dL). The serum C-reactive protein level was elevated (8.3 mg/ dL), and the brain natriuretic peptide level was 268 pg/mL. A chest radiograph showed no pulmonary congestion with a cardiothoracic ratio of 50 % and an electrocardiogram revealed a sinus rhythm of 60 beats/min. Transthoracic echocardiography revealed a left ventricular diastolic dimension of 57 mm, left ventricular systolic dimension of 33 mm, ejection fraction of 72 %, and severe aortic regurgitation with a quadricuspid aortic valve. After admission, Corynebacterium striatum was detected in the blood culture. In addition, transesophageal echocardiography revealed vegetation (14 9 9 mm) attached to the quadricuspid aortic valve and a small accessory cusp between the noncoronary and left coronary cusps (Fig. 1). Thus, we diagnosed a quadricuspid aortic valve with infective endocarditis and intravenous antibiotic therapy (6-g/day ampicillin/sulbactam and 60-mg/day gentamycin) was initiated immediately. Despite the antibiotic treatment, the C-reactive protein level increased again, and the size of the vegetation was not reduced on echocardiography. Therefore, surgery was performed on day 21 of hospitalization. The operation was performed via a median
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Surg Today
Fig. 1 Transesophageal echocardiograms. a Mid-esophageal aortic valve short-axis view at the 60° scanning plane shows a quadricuspid aortic valve with three equal-sized cusps and one smaller cusp. b Midesophageal aortic valve long-axis view at the 105° scanning plane
shows vegetation attached to the quadricuspid aortic valve (arrow). NCC noncoronary cusp, LCC left coronary cusp, RCC right coronary cusp
Jude Medical, St. Paul, MN). Antibiotic therapy was continued postoperatively, and complete remission and relief of the leg edema were achieved. Hence, she was discharged from hospital on postoperative day 44. The patient has been followed up regularly at our hospital for the management of anticoagulation therapy and preservation period of chronic kidney disease.
Discussion
Fig. 2 Operative findings of the aortic valve. Photograph obtained after aortomy. Vegetation was found on the noncoronary cusp of the aortic side (asterisk). Multiple vegetations were attached to the left ventricular side of the left coronary, right coronary, and accessory cusps (arrows). Acc accessory cusp
sternotomy with moderate systemic hypothermia and cold cardioplegia. After aortomy, the aortic valve was found to be composed of four cusps with multiple vegetations (Fig. 2); that is, three equal-sized cusps and one smaller cusp (type B according to the Hurwitz classification). After dissecting the vegetation and infectious focus, we implanted a 19-mm St. Jude Medical Regent prosthesis (St.
123
Congenital quadricuspid aortic valve is a rare cardiac malformation, with a reported incidence of 0.008–0.03 % at autopsy [1, 2]. With technological advances in echocardiography, quadricuspid aortic valve has been increasingly diagnosed before surgery, at an estimated incidence of 0.013 % [3]. Of the seven most common anatomic variations of quadricuspid semilunar valves (types A–G) described by Hurwitz and Roberts [2], more than 85 % are of type A (4 equal-sized cusps), B (3 equal-sized cusps and 1 smaller cusp) or C (2 larger equal-sized cusps and 2 smaller equal-sized cusps) [3]. Concerning valvular function, aortic regurgitation usually develops as a result of fibrous thickening with incomplete coaptation [3]. The risk of infective endocarditis is unclear; however, a quadricuspid aortic valve complicated with infective endocarditis is extremely rare. Simonds [1] was the first to report an autopsy case of quadricuspid aortic valve with infective endocarditis, in 1923. Apart from autopsy cases, only seven case reports have been published to our knowledge [4–9] (Table 1). Feldman et al. [10] suggested that with cusps of nearly equal area, transvalvular forces are equally disturbed. In contrast, the unequal distribution of stress and abnormal leaflet coaptation with a small accessory cusp can result in
Surg Today Table 1 Reported cases of a quadricuspid aortic valve complicated with infective endocarditis No.
Reference
Age (years)
Sex
Aortic valve function
Type
Aortic vegetation
Aortic cusp perforation
Bacteria
Cardiac complication
Operation
1
Matsukawa et al. [4]
75
M
Severe AR
A
None
?
b-Streptococcus
None
AVR
2
Finch et al. [5]
33
M
Severe AR
?
None
?
ND
SVA (abscess) Single coronary
AVR
3
Asami et al. [6]
50
M
Severe AR
A
None
-
ND
Mitral valve vegetation
DVR
4
Takeda et al. [7]
26
F
Severe AR
F
None
?
ND
None
AVR
5
Watanabe et al. [8]
62
F
Mild AR
A
Small vegetation
-
PRSP
C-AV block
AVR
6
Bauer et al. [9]
68
M
Severe AR
A
Multiple vegetations
-
Streptococcus oralis
None
AVR
7
This case
53
F
Severe AR
B
Multiple vegetations
-
Corynebacterium striatum
None
AVR
AR aortic regurgitation, PRSP penicillin-resistant strains of Streptococcus pneumoniae, ND not detected, SVA sinus of Valsalva aneurysm, C-AV block complete atrioventricular block, AVR aortic valve replacement, DVR double valve replacement, Type A four equal cusps, Type B three equal cusps and one smaller cusp, Type F two equal larger cusps and two unequal smaller cusps
progressive aortic regurgitation. Moreover, severe aortic regurgitation can develop in patients with a small accessory cusp; therefore, valves with four equal-sized cusps (type A) have been considered more likely to induce normal function. Timperley et al. [3] reviewed 114 reported cases of a quadricuspid aortic valve. They identified a type A quadricuspid aortic valve with normal function in 3 (10 %) of 30 patients. In contrast, a type B quadricuspid aortic valve was found in 13 (32.5 %) among 40 patients without any significant difference in average ages, and normally functioning valves were found more frequently in the type B group than in the type A group. They suggested that four equal-sized leaflets are not more likely to induce normal function than an unequal-sized leaflet, as originally believed. Some reports suggest that a quadricuspid aortic valve with infective endocarditis is typically characterized by unequal-sized leaflets [6, 8, 9]. However, at least four of the seven reported cases of quadricuspid aortic valve with infective endocarditis were of type A. It seems that the predisposition to infective endocarditis might not be dependent on whether the cusps are equal in size. Thus, we hypothesize that irrespective of its type, a quadricuspid aortic valve can result in infective endocarditis. Surgical techniques of aortic valve repair for quadricuspid aortic valve, such as tricuspidization [11] or aortic valve reconstruction [12], have been reported. Ozaki et al. [12] reported good mid-term results following aortic valve reconstruction with autologous pericardium and suggested that this could be applied to a wide spectrum of aortic valve diseases, including infective endocarditis. Because a quadricuspid aortic valve is a congenital anomaly, for
juveniles, particularly young women, aortic valve repair might be indicated as a potential option with respect to avoiding warfarin administration. Further long-term results and comparison of bioprosthetic valves are expected. Infective endocarditis is associated with poor prognosis and high mortality rates. Many factors affect the outcome of this serious disease, including virulence of the microorganism, patients’ characteristics, the presence of underlying disease, delays in diagnosis and treatment, surgical indications, and timing of surgery [13]. Although our patient had a high-grade fever 5 months previously, she was admitted to hospital only after worsening of her heart failure. This process is considered one of the factors predisposing to a worse clinical outcome for infective endocarditis: Early diagnosis and definitive treatment should be initiated to improve the prognosis. In conclusion, we reported a rare case of a quadricuspid aortic valve complicated with infective endocarditis. In general, it is necessary to dissect the vegetation or infectious focus. We think that aortic valve replacement should be the standard operative procedure.
Conflict of interest to disclose.
We have no conflicts of interest or relationships
References 1. Simonds JP. Congenital malformations of aortic and pulmonary valves. Am J Med Sci. 1923;166:584–95. 2. Hurwitz LE, Roberts WC. Quadricuspid semilunar valve. Am J Cardiol. 1973;31:623–6.
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Surg Today 3. Timperley J, Milner R, Marshall AJ, Gilbert TJ. Quadricuspid aortic valves. Clin Cardiol. 2002;25:548–52. 4. Matsukawa T, Yoshii S, Hashimoto R, Muto S, Suzuki S, Ueno A. Quadricuspid aortic valve perforation resulting from bacterial endocarditis-2-D echo- and angiographic diagnosis and its surgical treatment. Jpn Circ J. 1988;52:437–40. 5. Finch A, Osman K, Kim KS, Nanda N, Willman B, Soto B, et al. Transesophageal echocardiographic findings of an infected quadricuspid aortic valve with an anomalous coronary artery. Echocardiography. 1994;11:369–75. 6. Asami H, Asano H, Handa N, Kakamura S, Ogiwara M, Ueda K, et al. A surgical case of quadricuspid aortic valve associated aortic regurgitation and severe mitral regurgitation due to infective endocarditis. Kyobu Geka. 1998;51:216–9 (in Japanese). 7. Takeda N, Ohtaki E, Kasegawa H, Tobaru T, Sumiyoshi T. Infective endocarditis assisted with quadricuspid aortic valve. Jpn Heart J. 2003;44:441–5. 8. Watanabe Y, Taketani Y, Takei Y, Tanaka K, Watanabe Y. Complete heart block resulting from quadricuspid aortic valve penicillin-resistant pneumococcal endocarditis: a case report. Circ J. 2003;67:275–6.
123
9. Bauer F, Litzler PY, Tabley A, Cribier A, Bessou JP. Endocarditis complicating a congenital quadricuspid aortic valve. Eur J Echocardiogr. 2008;9:386–7. 10. Feldman BJ, Khandheria BK, Warnes CA, Seward JB, Taylor CL, Tajik AJ. Incidence, description and functional assessment of isolated quadricuspid aortic valves. Am J Cardiol. 1990;65: 937–8. 11. Schmidt KI, Jeserich M, Aicher D, Scha¨fers HJ. Tricuspidization of the quadricuspid aortic valve. Ann Thorac Surg. 2008;85: 1087–9. 12. Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M, et al. A total 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium. J Thorac Cardiovasc Surg. 2012;. doi:10.1016/j.jtcvs.2012.11.012. 13. Thuney F, Grisoli D, Collart F, Habib G, Raoult D. Management of infective endocarditis: challenges and perspectives. Lancet. 2012;379:965–75.
CASE REPORT
Quadricuspid aortic valve complicated with infective endocarditis: report of a case Hiroki Mizoguchi • Masayuki Sakaki • Kazushige Inoue • Yasuhiko Kobayashi • Takashi Iwata • Yasuo Suehiro • Takuya Miura
Received: 26 January 2013 / Accepted: 5 August 2013 Ó Springer Japan 2014
Abstract Congenital quadricuspid aortic valve is a rare cardiac malformation with an unknown risk of infective endocarditis. We report a case of quadricuspid aortic valve complicated with infective endocarditis. A 53-year-old Japanese woman was hospitalized with leg edema and a fever of unknown origin. Corynebacterium striatum was detected in the blood culture. Echocardiography demonstrated a quadricuspid aortic valve with vegetation and severe functional regurgitation. The condition was diagnosed as a quadricuspid aortic valve with infective endocarditis, for which surgery was performed. The quadricuspid aortic valve had three equal-sized cusps and one smaller cusp (type B according to Hurwitz classification). We dissected the vegetation and infectious focus and implanted a mechanical valve. Following the case report, we review the literature. Keywords Quadricuspid aortic valve Infective endocarditis Vegetation Aortic regurgitation Aortic valve replacement
Introduction Congenital quadricuspid aortic valve is a rare cardiac malformation with an unknown risk of infective endocarditis. We report an extremely rare case of quadricuspid aortic valve complicated with infective endocarditis, followed by a review of the literature.
H. Mizoguchi (&) M. Sakaki K. Inoue Y. Kobayashi T. Iwata Y. Suehiro T. Miura Department of Cardiovascular Surgery, Kansai Rosai Hospital, 3-1-69 Inabasou, Amagasaki, Hyogo 660-8511, Japan e-mail: [email protected]
Case report A 53-year-old Japanese woman was hospitalized for investigation of leg edema and a fever of unknown origin. She had a high-grade fever 5 months previously. The patient had not received dental treatment or steroid therapy and had no history of rheumatic fever or heart disease. At presentation, her temperature was 38.3 °C and her blood pressure was 108/55 mmHg, with a regular pulse rate of 62 beats/min. A grade 4/6 cardiac systolic ejection murmur was audible in the fourth intercostal space at the left sternal border. Laboratory tests showed anemia (hemoglobin level, 4.1 g/dL) and renal failure (creatinine level, 2.13 mg/dL). The serum C-reactive protein level was elevated (8.3 mg/ dL), and the brain natriuretic peptide level was 268 pg/mL. A chest radiograph showed no pulmonary congestion with a cardiothoracic ratio of 50 % and an electrocardiogram revealed a sinus rhythm of 60 beats/min. Transthoracic echocardiography revealed a left ventricular diastolic dimension of 57 mm, left ventricular systolic dimension of 33 mm, ejection fraction of 72 %, and severe aortic regurgitation with a quadricuspid aortic valve. After admission, Corynebacterium striatum was detected in the blood culture. In addition, transesophageal echocardiography revealed vegetation (14 9 9 mm) attached to the quadricuspid aortic valve and a small accessory cusp between the noncoronary and left coronary cusps (Fig. 1). Thus, we diagnosed a quadricuspid aortic valve with infective endocarditis and intravenous antibiotic therapy (6-g/day ampicillin/sulbactam and 60-mg/day gentamycin) was initiated immediately. Despite the antibiotic treatment, the C-reactive protein level increased again, and the size of the vegetation was not reduced on echocardiography. Therefore, surgery was performed on day 21 of hospitalization. The operation was performed via a median
123
Surg Today
Fig. 1 Transesophageal echocardiograms. a Mid-esophageal aortic valve short-axis view at the 60° scanning plane shows a quadricuspid aortic valve with three equal-sized cusps and one smaller cusp. b Midesophageal aortic valve long-axis view at the 105° scanning plane
shows vegetation attached to the quadricuspid aortic valve (arrow). NCC noncoronary cusp, LCC left coronary cusp, RCC right coronary cusp
Jude Medical, St. Paul, MN). Antibiotic therapy was continued postoperatively, and complete remission and relief of the leg edema were achieved. Hence, she was discharged from hospital on postoperative day 44. The patient has been followed up regularly at our hospital for the management of anticoagulation therapy and preservation period of chronic kidney disease.
Discussion
Fig. 2 Operative findings of the aortic valve. Photograph obtained after aortomy. Vegetation was found on the noncoronary cusp of the aortic side (asterisk). Multiple vegetations were attached to the left ventricular side of the left coronary, right coronary, and accessory cusps (arrows). Acc accessory cusp
sternotomy with moderate systemic hypothermia and cold cardioplegia. After aortomy, the aortic valve was found to be composed of four cusps with multiple vegetations (Fig. 2); that is, three equal-sized cusps and one smaller cusp (type B according to the Hurwitz classification). After dissecting the vegetation and infectious focus, we implanted a 19-mm St. Jude Medical Regent prosthesis (St.
123
Congenital quadricuspid aortic valve is a rare cardiac malformation, with a reported incidence of 0.008–0.03 % at autopsy [1, 2]. With technological advances in echocardiography, quadricuspid aortic valve has been increasingly diagnosed before surgery, at an estimated incidence of 0.013 % [3]. Of the seven most common anatomic variations of quadricuspid semilunar valves (types A–G) described by Hurwitz and Roberts [2], more than 85 % are of type A (4 equal-sized cusps), B (3 equal-sized cusps and 1 smaller cusp) or C (2 larger equal-sized cusps and 2 smaller equal-sized cusps) [3]. Concerning valvular function, aortic regurgitation usually develops as a result of fibrous thickening with incomplete coaptation [3]. The risk of infective endocarditis is unclear; however, a quadricuspid aortic valve complicated with infective endocarditis is extremely rare. Simonds [1] was the first to report an autopsy case of quadricuspid aortic valve with infective endocarditis, in 1923. Apart from autopsy cases, only seven case reports have been published to our knowledge [4–9] (Table 1). Feldman et al. [10] suggested that with cusps of nearly equal area, transvalvular forces are equally disturbed. In contrast, the unequal distribution of stress and abnormal leaflet coaptation with a small accessory cusp can result in
Surg Today Table 1 Reported cases of a quadricuspid aortic valve complicated with infective endocarditis No.
Reference
Age (years)
Sex
Aortic valve function
Type
Aortic vegetation
Aortic cusp perforation
Bacteria
Cardiac complication
Operation
1
Matsukawa et al. [4]
75
M
Severe AR
A
None
?
b-Streptococcus
None
AVR
2
Finch et al. [5]
33
M
Severe AR
?
None
?
ND
SVA (abscess) Single coronary
AVR
3
Asami et al. [6]
50
M
Severe AR
A
None
-
ND
Mitral valve vegetation
DVR
4
Takeda et al. [7]
26
F
Severe AR
F
None
?
ND
None
AVR
5
Watanabe et al. [8]
62
F
Mild AR
A
Small vegetation
-
PRSP
C-AV block
AVR
6
Bauer et al. [9]
68
M
Severe AR
A
Multiple vegetations
-
Streptococcus oralis
None
AVR
7
This case
53
F
Severe AR
B
Multiple vegetations
-
Corynebacterium striatum
None
AVR
AR aortic regurgitation, PRSP penicillin-resistant strains of Streptococcus pneumoniae, ND not detected, SVA sinus of Valsalva aneurysm, C-AV block complete atrioventricular block, AVR aortic valve replacement, DVR double valve replacement, Type A four equal cusps, Type B three equal cusps and one smaller cusp, Type F two equal larger cusps and two unequal smaller cusps
progressive aortic regurgitation. Moreover, severe aortic regurgitation can develop in patients with a small accessory cusp; therefore, valves with four equal-sized cusps (type A) have been considered more likely to induce normal function. Timperley et al. [3] reviewed 114 reported cases of a quadricuspid aortic valve. They identified a type A quadricuspid aortic valve with normal function in 3 (10 %) of 30 patients. In contrast, a type B quadricuspid aortic valve was found in 13 (32.5 %) among 40 patients without any significant difference in average ages, and normally functioning valves were found more frequently in the type B group than in the type A group. They suggested that four equal-sized leaflets are not more likely to induce normal function than an unequal-sized leaflet, as originally believed. Some reports suggest that a quadricuspid aortic valve with infective endocarditis is typically characterized by unequal-sized leaflets [6, 8, 9]. However, at least four of the seven reported cases of quadricuspid aortic valve with infective endocarditis were of type A. It seems that the predisposition to infective endocarditis might not be dependent on whether the cusps are equal in size. Thus, we hypothesize that irrespective of its type, a quadricuspid aortic valve can result in infective endocarditis. Surgical techniques of aortic valve repair for quadricuspid aortic valve, such as tricuspidization [11] or aortic valve reconstruction [12], have been reported. Ozaki et al. [12] reported good mid-term results following aortic valve reconstruction with autologous pericardium and suggested that this could be applied to a wide spectrum of aortic valve diseases, including infective endocarditis. Because a quadricuspid aortic valve is a congenital anomaly, for
juveniles, particularly young women, aortic valve repair might be indicated as a potential option with respect to avoiding warfarin administration. Further long-term results and comparison of bioprosthetic valves are expected. Infective endocarditis is associated with poor prognosis and high mortality rates. Many factors affect the outcome of this serious disease, including virulence of the microorganism, patients’ characteristics, the presence of underlying disease, delays in diagnosis and treatment, surgical indications, and timing of surgery [13]. Although our patient had a high-grade fever 5 months previously, she was admitted to hospital only after worsening of her heart failure. This process is considered one of the factors predisposing to a worse clinical outcome for infective endocarditis: Early diagnosis and definitive treatment should be initiated to improve the prognosis. In conclusion, we reported a rare case of a quadricuspid aortic valve complicated with infective endocarditis. In general, it is necessary to dissect the vegetation or infectious focus. We think that aortic valve replacement should be the standard operative procedure.
Conflict of interest to disclose.
We have no conflicts of interest or relationships
References 1. Simonds JP. Congenital malformations of aortic and pulmonary valves. Am J Med Sci. 1923;166:584–95. 2. Hurwitz LE, Roberts WC. Quadricuspid semilunar valve. Am J Cardiol. 1973;31:623–6.
123
Surg Today 3. Timperley J, Milner R, Marshall AJ, Gilbert TJ. Quadricuspid aortic valves. Clin Cardiol. 2002;25:548–52. 4. Matsukawa T, Yoshii S, Hashimoto R, Muto S, Suzuki S, Ueno A. Quadricuspid aortic valve perforation resulting from bacterial endocarditis-2-D echo- and angiographic diagnosis and its surgical treatment. Jpn Circ J. 1988;52:437–40. 5. Finch A, Osman K, Kim KS, Nanda N, Willman B, Soto B, et al. Transesophageal echocardiographic findings of an infected quadricuspid aortic valve with an anomalous coronary artery. Echocardiography. 1994;11:369–75. 6. Asami H, Asano H, Handa N, Kakamura S, Ogiwara M, Ueda K, et al. A surgical case of quadricuspid aortic valve associated aortic regurgitation and severe mitral regurgitation due to infective endocarditis. Kyobu Geka. 1998;51:216–9 (in Japanese). 7. Takeda N, Ohtaki E, Kasegawa H, Tobaru T, Sumiyoshi T. Infective endocarditis assisted with quadricuspid aortic valve. Jpn Heart J. 2003;44:441–5. 8. Watanabe Y, Taketani Y, Takei Y, Tanaka K, Watanabe Y. Complete heart block resulting from quadricuspid aortic valve penicillin-resistant pneumococcal endocarditis: a case report. Circ J. 2003;67:275–6.
123
9. Bauer F, Litzler PY, Tabley A, Cribier A, Bessou JP. Endocarditis complicating a congenital quadricuspid aortic valve. Eur J Echocardiogr. 2008;9:386–7. 10. Feldman BJ, Khandheria BK, Warnes CA, Seward JB, Taylor CL, Tajik AJ. Incidence, description and functional assessment of isolated quadricuspid aortic valves. Am J Cardiol. 1990;65: 937–8. 11. Schmidt KI, Jeserich M, Aicher D, Scha¨fers HJ. Tricuspidization of the quadricuspid aortic valve. Ann Thorac Surg. 2008;85: 1087–9. 12. Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M, et al. A total 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium. J Thorac Cardiovasc Surg. 2012;. doi:10.1016/j.jtcvs.2012.11.012. 13. Thuney F, Grisoli D, Collart F, Habib G, Raoult D. Management of infective endocarditis: challenges and perspectives. Lancet. 2012;379:965–75.
