Endocarditis





Native valve endocarditis


CASE 4-1


Aortic valve endocarditis


This 39-year-old female with a history of intravenous drug use, uncontrolled diabetes, and chronic pancreatitis had recently undergone a 21-day course of antibiotics for a soft tissue infection of her hand. In the 2 days before admission she had become severely fatigued and more short of breath on exertion. Auscultation of a murmur prompted a transthoracic echocardiogram that showed vegetations on the aortic valve, severe eccentric aortic regurgitation (AR), and biventricular dysfunction. She was referred for aortic valve surgery for acute heart failure resulting from severe aortic regurgitation secondary to presumptive endocarditis. Postop pathologic examination of the native aortic leaflets showed evolving endocarditis with gram-positive organisms, consistent with treated endocarditis.



Fig 4.1


Preoperative TTE apical five-chamber view showed a broad jet of AR (white arrow) .



Fig 4.2


Preoperative TTE showed a pressure half-time of the AR jet to be 153 ms (left) , and diastolic flow reversal in the abdominal aorta. Both parameters are consistent with severe AR.



Fig 4.3


In this midesophageal short-axis image in diastole (left panel) , there are multiple echo-dense masses attached to the valve leaflets but with independent mobility, consistent with aortic valve vegetations (arrow) . There is no evidence for paravalvular abscess. The systolic image (right panel) shows one of the vegetations engaging the left main coronary artery (LMCA) orifice (arrow) , illustrating how embolization from an aortic valve vegetation can result in myocardial infarction as well as mycotic aneurysm of the coronary artery.



Fig 4.4


In this midesophageal long-axis image in diastole, multiple echodensities with independent motion consistent with aortic valve vegetations are again seen (left panel, arrow) . Color Doppler flow imaging (right) shows eccentric aortic regurgitation. Vena contracta is difficult to measure on this image as the jet courses obliquely across the outflow tract so that the minor axis diameter of the flow stream cannot be identified.



Fig 4.5


In this 3D view of the aortic valve from the perspective of the ascending aorta, vegetations are seen at the left (red arrow) and noncoronary (white arrow) cusps.



Fig 4.6


The transgastric two-chamber image (left) demonstrates significant LV dilation with an end-diastolic diameter of 6.3 cm. Speckle tracking in a midpapillary short-axis view shows a reduced circumferential strain of –9.9% consistent with moderately reduced overall systolic function. The biplane ejection fraction (EF) was 34%. These findings are unusual for acute severe aortic regurgitation, suggesting that chronic aortic regurgitation was present or that there is concurrent primary myocardial dysfunction.



Fig 4.7


These transgastric short-axis (left) and long-axis (right) views show RV dilation. In real time there is mildly reduced RV function.



Fig 4.8


This midesophageal short-axis image in diastole (left) and systole (right) of the bioprosthetic aortic valve replacement shows thin leaflets with normal systolic opening. There was no aortic regurgitation on color Doppler imaging.



Fig 4.9


This midesophageal long-axis image in diastole (left) and systole (right) of the bioprosthetic valve replacement shows normal thin leaflets with diastolic closure and no regurgitation on color Doppler imaging. There was normal systolic opening.



Fig 4.10


A 3D image of the bioprosthetic valve as seen from the perspective of the ascending aorta. In real time, there is some artifactual dropout of the leaflets.



Fig 4.11


The Trifecta bioprosthesis (St. Jude Medical, St. Paul, Minnesota). In the left panel, the valve as it appears before implantation. The center panel shows the valve just before lowering into position. In the right panel, the valve has been sutured down to the annulus.




Comments


The clinical diagnosis of endocarditis is based on a combination of clinical, bacteriologic, and echocardiographic findings, known as the Duke criteria. In brief, definite endocarditis is present when there is evidence of persistent bacteremia plus echocardiographic findings consistent with endocardial infection. When only one rather than both of these criteria is present, other minor clinical criteria are used to support the diagnosis of endocarditis. A vegetation is recognized with echocardiography as an irregular mass attached to a valve leaflet but with motion independent of the normal valve motion. Vegetations are typically located on the upstream side of valves, such as the ventricular side of the aortic valve and the atrial side of the mitral valve. This case is atypical with vegetations seen on the aortic side of the valve, which is more typical for nonbacterial endocarditis.


Valvular regurgitation is present in over 90% of cases, due either to the vegetation interfering with normal valve closure or, more often, to tissue destruction with loss of leaflet tissue or perforation. Stenosis caused by a large vegetation is rare. Transesophageal echocardiography has a very high (nearly 100%) sensitivity and specificity for detection of valvular vegetations. Other echocardiographic findings that may be mistaken for a valvular vegetation include beam width artifact, normal valve tissue (i.e., myxomatous valve disease, Lambl’s excrescence), prosthetic valve thrombus, papillary fibroelastoma, and nonbacterial thrombotic endocarditis.


Suggested reading




  • 1.

    Wang A, Samad Z: Endocarditis: the role of echocardiography in diagnosis and decision-making. In Otto CM, editor: The practice of clinical echocardiography, ed 5, Philadelphia, 2016, Elsevier.


  • 2.

    Thuny F, Grisoli D, Cautela J, et al: Infective endocarditis: prevention, diagnosis, and management, Can J Cardiol 30(9): 1046–1057, 2014.


  • 3.

    Thanavaro KL, Nixon JV: Endocarditis 2014: An update, Heart Lung 43(4):334–337, 2014.


  • 4.

    Kaku K, Takeuchi M, Tsang W, et al: Age-related normal range of left ventricular strain and torsion using three-dimensional speckle-tracking echocardiography, J Am Soc Echocardiogr 27:55–64, 2014.



CASE 4-2


Aortic and mitral valve vegetations


This 35-year-old man presented with a 6-week history of malaise and a 2-week history of fevers, chills, and right upper quadrant abdominal pain. After an abdominal ultrasound, he was started on antibiotics for ascending cholangitis. However, he continued to deteriorate clinically with sepsis and multiple blood cultures positive for Haemophilus influenzae. After further respiratory and hemodynamic compromise, he underwent echocardiography, which was consistent with aortic and mitral valve endocarditis, severe aortic regurgitation, and moderate mitral regurgitation. He developed cardiogenic shock and his mental status declined. Head CT showed focal right frontal lobe hypodensities consistent with embolic stroke. Because of his hemodynamic instability, he was taken to the OR for emergency aortic valve replacement.



Fig 4.12


Posterior-anterior chest radiography shows cardiac enlargement and pulmonary edema.



Fig 4.13


Long-axis TEE view of the aortic valve and ascending aorta demonstrates normal aortic root size and anatomy. However, there is a discontinuity in the anterior leaflet of the aortic valve (arrow) with color Doppler showing a wide jet of aortic regurgitation through this region.



Fig 4.14


In the left panel, the midesophageal short-axis TEE view of the aortic valve demonstrates a valvular vegetation at the junction between the right (RCC) and left coronary cusps (LCC). The posteriorly located noncoronary cusp (NCC) appears normal in this view. Color Doppler in a short-axis view of the left ventricular outflow tract shows aortic regurgitation (mosaic green pattern, arrow) filling about two-thirds of the cross-sectional area of flow (right panel) .



Fig 4.15


Images of the mitral valve at 0 degrees demonstrate large mobile masses on both leaflets. In real time, these masses move independently from the valve leaflets and are consistent with vegetations. Color Doppler shows a wide jet of mitral regurgitation with both anteriorly and posteriorly directed jets (arrows) .



Fig 4.16


At surgical inspection, the 1-cm diameter vegetation at the junction of the left and right coronary cusps of the aortic valve is seen (arrow, left panel) . With the LA opened, the large vegetation on the anterior mitral leaflet can be appreciated (right panel) . Both anterior and posterior leaflets were extensively destroyed by the infectious process. The man underwent mechanical aortic and mitral valve replacements. Although his postoperative course was complicated, 2 years after surgery he is doing well clinically on medical therapy for a left ventricular ejection fraction of 36% with moderate paravalvular aortic regurgitation.




Comments


Vegetations are described on echocardiography in terms of location, size, mobility, and echodensity. The exact location on the valve may help determine whether valve repair, rather than replacement, is possible. Vegetation size and mobility are markers of increased risk of complications of endocarditis. The density of a vegetation may provide clues about the chronicity of disease, with denser, calcified vegetations suggesting chronic or healed endocarditis.


In patients with underlying valve disease, bacteremia may result in direct infection at more than one site. Even when one valve is primarily infected, vegetations may occur on other valves resulting from direct extension of the infection. An example is an aortic annular abscess eroding into the base of the anterior mitral leaflet. Infection of one valve may also damage an adjacent valve, leading to subsequent infection. For example, aortic regurgitation impinging on the anterior mitral leaflet results in endothelial disruption with a higher likelihood of bacterial adherence at that site. Thus one of the primary goals of intraoperative TEE in patients undergoing valve surgery for endocarditis is to exclude infection on the other “uninvolved” valves.


Suggested reading




  • 1.

    Bruun NE, Habib G, Thuny F, et al: Cardiac imaging in infectious endocarditis, Eur Heart J 35(10):624–632, 2014.


  • 2.

    Bedeir K, Reardon M, Ramlawi B: Infective endocarditis: Perioperative management and surgical principles, J Thorac Cardiovasc Surg 147(4):1133–1141, 2014.



CASE 4-3


Mitral valve endocarditis with perforated anterior leaflet


The patient is a 29-year-old male who presented to his primary care provider complaining of several months of chills, fatigue, and a 25-lb unintentional weight loss. Evaluation revealed a prominent new systolic murmur. He was sent for an echocardiogram that revealed a 1.7 × 1.4 cm mitral valve vegetation with significant mitral regurgitation.



Fig 4.17


In the left panel, a midesophageal long-axis view demonstrates a perforation of the anterior mitral leaflet (green arrow) . The white arrow indicates the mitral orifice. The red arrow indicates fluid in the transverse pericardial sinus with a “mass” that is the normal left atrial appendage. The surgeon confirmed that there was no abnormal mass in the pericardial space. In the middle panel, two jets of mitral regurgitation are seen with proximal isovelocity surface areas (PISAs) on the LV side of the valve, as indicated by the white arrows. The location of the PISAs helps identify the exact site of leaflet perforation. In the right panel, a 3D image of the mitral valve from the left atrial perspective illustrates a perforation in the anterior mitral leaflet (arrow) .

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Dec 30, 2019 | Posted by in CARDIOLOGY | Comments Off on Endocarditis

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