Ann Thorac Surg 2009;87:1585-1587. doi:10.1016/j.athoracsur.2008.09.015
© 2009 The Society of Thoracic Surgeons
Case Reports
Aortic Valve Infective Endocarditis: Could Multi-Detector CT Scan Be Proposed for Routine Screening of Concomitant Coronary Artery Disease Before Surgery?
Salvatore Lentini, MD*,
Francesco Monaco, MD,
Fabrizio Tancredi, MD,
Marcello Savasta, MD,
Roberto Gaeta, MD
Cardiac Surgery Unit, Policlinic Hospital, University of Messina, Messina, Italy
Accepted for publication September 3, 2008.
* Address correspondence to Dr Lentini, UOC di Cardiochirurgia, Pad H, AOU Policlinico Universitario, Viale Gazzi, Messina, 98100, Italy (Email: salvolentini{at}alice.it).
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Abstract
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Usefulness of the coronary artery study has been questioned in patients with infective valve endocarditis. Fatal events are reported in the literature due to embolization of endocarditic vegetations during cardiac catheterization. For this reason, many authors do not recommend preoperative invasive coronary studies in these patients. We report the case of a 56-year-old patient with prosthetic valve endocarditis with vegetations, and concomitant risk factors for coronary disease. We did preoperative coronary screening using multi-detector computed tomographic scan imaging, which may be useful for noninvasive imaging of the coronary arteries in these patients with high risk of embolization.
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Introduction
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Usefulness of the coronary artery study has been questioned in patients with infective valve endocarditis. Fatal events are reported in the literature, due to embolization of endocarditic vegetations during cardiac catheterization. For this reason, many authors perform cardiac surgery without preoperative coronary screening in these patients. We report the case of a 56-year-old man with prosthetic valve endocarditis with vegetations, and concomitant risk factors for coronary disease. We did preoperative coronary screening using multi-detector computed tomographic imaging.
In January 2008, a 56-year-old man was referred to our institution with diagnosis of infective endocarditis on a prosthetic biological aortic heart valve (Carpentier-Edwards; Edwards Lifesciences Inc, Irvine, CA) implanted 5 years before. The patient presented with recurrent fever, leukocytosis, and congestive heart failure. Physical examination showed a systo-diastolic apical heart murmur, enlarged liver, and edema of the ankles. The echocardiographic appearance was that of a "rocking" valve with some fluctuating vegetations on the aortic side. The prosthesis seemed not to be completely attached to the aortic annulus. A peri-annular abscess was also seen. Other echocardiographic findings were: normal left ventricular function, mild mitral regurgitation, and estimated pulmonary artery pressure of 45 mm Hg. Repeated blood cultures were negative, despite persistent fever. Antimicrobial therapy (ie, vancomycin, gentamicin, and rifampicin) was started on an empirical basis. The patient was scheduled for urgent surgical replacement of the infected valve and treatment of the abscess. However, because the patient also had concomitant risk factors for atherosclerotic disease, such as diabetes, smoking, and systemic arterial hypertension, we believed a preoperative assessment of the coronary vessels was useful. The presence of fluctuating vegetations discouraged us to perform a standard coronary angiography because of a high risk of iatrogenic embolization. We decided to perform a multi-detector computed tomographic scan (MDCT) of the heart to get some information on the presence of any concomitant critical coronary artery disease (Figs 1 and 2).
The MDCT image was considered negative for critical obstructive coronary disease.
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Fig 1. Multi-detector computed tomographic scan shows left ventricle outflow tract with para-prosthetic abscess, and left and right coronary arteries.
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Nevertheless, the amount of "coronary artery calcium" (CAC) was quantified. On the Agatson scale [1], a calcium score of 388.7 was obtained. A recent article [2] demonstrates lower incidence of acute cardiac events in patients with a calcium score lower than 400. The higher incidence is in patients with values over 1,000.
The MDCT also confirmed the presence of the para-annular abscess. Surgical intervention was then successfully carried out with replacement of the infected valve and insertion of a 21 mechanical valve (St. Jude Medical, St. Paul, MN) and treatment of the abscess. The patient was discharged home and kept on antibiotic therapy for 6 weeks afterwards. The patient has been seen in the outpatient clinic up to 4 months postoperatively. The patient remains well and in good general condition.
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Comment
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The need to perform a coronary angiogram in patients with infective endocarditis is not accepted by all authors. In the past, this procedure was considered useful in the preoperative evaluation of these patients and it was believed that careful catheter placement and minimum injection pressures could prevent embolic phenomena during coronary angiogram. However, fatal events are reported in the literature due to embolization of endocarditic vegetations during cardiac catheterization [3]. For this reason, to reduce the risk of iatrogenic embolization, many authors do not recommend invasive coronary studies in these patients, and they perform heart surgery without coronary screening [4]. In the case we described, the patient had concomitant risk factors for coronary disease. Preoperative screening for concomitant coronary disease was considered useful before surgical cardiac procedure. The presence of vegetations on the aortic valve discouraged us from performing a coronary angiogram.
In our case, we believed that a noninvasive imaging study, such as the MDCT, would have offered a compromise in obtaining some information on the coronary status in comparison with the invasive risk of a standard coronary angiogram. The MDCT, which is useful to better assess aortic root abscess and involvement of adjacent structures, in the same session, gave us some information on the conditions of the coronary tree.
The detection and quantification of coronary artery calcium, is a marker for atherosclerosis. The extent of coronary artery calcium strongly correlates with the overall magnitude of atherosclerotic plaque burden, with the development of subsequent coronary events [5].
Nowadays, clinical application of coronary MDCT is quite debated. However, there are more and more cardiology reports on the use of MDCTs as a noninvasive screening to exclude critical coronary disease in different clinical settings, even in the emergency department in patients with chest pain of possible ischemic origin [6].
Recent reports on preoperative computed tomographic coronary angiography to detect significant coronary artery disease in patients referred for cardiac valve surgery showed a good accuracy to exclude relevant coronary stenosis [7], with a sensitivity up to 96%, a specificity of 87%, a positive predictive value of 61%, and a negative predictive value of 99% for the detection of significant lesions (
50% diameter stenosis). The main reason for false-positive results is an overestimation of mild lesions by coronary computed tomographic (CT) scanning. Usually, the limitation of the CT scan is represented by an overestimation of stenosis, especially in the presence of calcifications [7]. This specificity and sensitivity, especially in the exclusion of significant lesions, may be of help in those cases at high risk of cathether-induced emboli.
In conclusion, we believe that the use of coronary MDCT scan, even if it cannot be considered yet an alternative to invasive angiogram, in this difficult clinical situation it may give some information when the invasive coronary study may result in a risk. Further investigations and a series of patients would be useful to better evaluate the benefit of coronary MDCT in these patients.
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References
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- Agatston AS, Janowitz WR, Hildner FJ, et al. Quantification of coronary artery calcium using ultrafast computed tomography J Am Coll Cardiol 1990;15:827-832.[Abstract]
- Ho Js, Fitzgerald SJ, Stolfus LL, et al. Relation of a coronary artery calcium score higher than 400 to coronary stenoses detected using multidetector computed tomography and to traditional cardiovascular risk factors Am J Cardiol 2008;101:1444-1447.[Medline]
- Shamsham F, Safi AM, Pomerenko I, et al. Fatal left main coronary artery embolism from aortic valve endocarditis following cardiac catheterization Catheter Cardiovasc Interv 2000;50:74-77.[Medline]
- David TE. Surgical treatment of aortic valve endocarditisIn: Lawrence H Cohn, editor. Cardiac surgery in the adult. 3rd edit.. New York, NY: McGraw-Hill; 2008. pp. 949-956.
- Raggi P, Callister TQ, Cooil B, et al. Identification of patients at increased risk of first unheralded acute myocardial infarction by electron-beam computed tomography Circulation 2000;101:850-855.[Abstract/Free Full Text]
- Rubinshtein R, Halon DA, Gaspar T, et al. Usefulness of 64-slice cardiac computed tomographic angiography for diagnosing acute coronary syndromes and predicting clinical outcome in emergency department patients with chest pain of uncertain origin Circulation 2007;115:1762-1768.[Abstract/Free Full Text]
- Nikolaou K, Knez A, Rist C, et al. Accuracy of 64-MDCT in the diagnosis of ischemic heart disease AJR Am J Roentgenol 2006;187:111-117.[Abstract/Free Full Text]
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Abstract
Introduction
