Ultrasound

The Reliability of Echocardiography in the Diagnosis of Infective Endocarditis 1 Kenneth R. Thomson, M.B., Ch.B., M.R.A.C.R.,2 Navin C. Nanda, M.D., and Raymond Gramiak, M.D.

The echocardiograms of 17 patients with proved infective endocarditis were surveyed to assess the reliability of echocardiography in thisdisease. Vegetations werepresent on 20 valves (11 aortic, 7 mitral, 2 tricuspid) at surgery or autopsy. Echocardiography correctly identified the abnormality in 11 valves. There were8 valves with false-negative studies of which only one examination was technically inadequate. One false-positive echocardiogram was found. A negative echocardiogram does not exclude infective endocarditis. The size of the vegetation is not the only consideration in its detection echocardiographically. False-positive and false negative studies are discussed. INDEX TERMS: (Cardiac valve, infection, 5[3].210). Heart, inflammation • Heart, ultrasound 5 [8] .1298 • Heart, valves Radiology 125:473-476, November 1977 NFECTIVE ENDOCARDITIS most often involves the cardiac valves and can be detected by echocardiography. In 1972 Schelbert and Muller (13) described the echocardiographic recognition of vegetations on a StarrEdwards mitral prosthesis. More recent papers have described the echocardiographic appearance of vegetations on the natural aortic, mitral and tricuspid valves but the reliability of echocardiography in the detection of vegetations remains unclear. In this paper, we shall review our experience in endocarditis involving heart valves and attempt to determine the reliability of echocardiography in detection of vegetations.

TABLE

I

I:

ECHOCARDIOGRAPHIC CRITERIA FOR DIAGNOSIS OF INFECTIVE ENDOCARDITIS

VEGETATIONS

(A) Aortic valve a. Shaggy nonuniform thickening in systole and/or diastole with unrestricted leaflet motion. b. Shaggy echoes moving longitudinally across the aortic valve. (8) Mitral valve a. Thick shaggy echoes from either leaflet with unrestricted leaflet motion either attached to, or moving behind the leaflets. b. Systolic flutter of the prolapsing segments of the mitral valve. (C) Tricuspid valve a. Shaggy thickening of the anterior leaflet with a mass of echoes behind the anterior leaflet.

experience and from those quoted in the literature. These are summarized in TABLE I.

METHOD AND MATERIAL

A study of 33 echocardiograms in 17 patients with proved infective endocarditis was made. The patients' ages ranged from 11 to 74 years with a mean of 43 years. Surgical and/or autopsy proof was available in 14 patients. In the 3 remaining patients the diagnosis was made with clinical, bacteriological and echocardiographic criteria alone. Fourteen patients had positive blood cultures on several occasions. The responsible organism was bacterial in 13 patients and fungal in one. Three patients with negative blood cultures had surgical proof of recent endocarditis. All echocardiographic examinations were performed with a commercially available echograph (Picker) and a. 2 MHz transducer. Continuous records were made on a 35mm film by means of a Fairchild oscilloscope record camera and a dual beam oscilloscope. In 16 patients, several echocardiographic studies of the four cardiac valves were obtained. In one patient, only the mitral valve could be examined. The diagnostic criteria used were obtained from our own

RESULTS

Aortic Valve Surgical or autopsy evidence of endocarditis was found on 11 aortic valves. In 5 of these the echocardiogram had correctly identified the presence of vegetations but not whether the vegetations were on the right, left or noncoronary cusp. These vegetations ranged in size from 1 mm to 2 cm in diameter but most were in the range of 2-5 mm. The density or thickness of the abnormal echoes was not a reliable indicator of their size. A 1mm vegetation containing calcification gave rise to echoes of similar appearance to those echoes from a 2-cm vegetation (Fig. 1). In 2 patients with aortic regurgitation and aortic valve vegetations, dense echoes were seen moving longitudinally across the aortic valve and prolapsing into the left ventricular outflow tract. One of these patients showed evidence of a sinus tract in the posterior aortic wall (Fig. 2).

1 From theDepartments of Radiology and Medicine (Cardiology Unit), University of Rochester School of Medicine and Dentistry, Rochester, N.Y. 14642. Presented in partat the FirstWorld Federation of Ultrasound in Medicine and Biology, San Francisco, Calif., August 1976. Accepted for publication in May 1977. 2 Present address: Department of Diagnostic Radiology, Flinders University of South Australia, Adelaide, South Australia. shan

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KENNETH

R.

THOMSON AND OTHERS

November 1977

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Fig. 3. Mitral valve involvement with bacterial endocarditis: The anterior leaflet image is thickened by a multilayered echo complex present in systole and diastole. The systolic segments sag, and the septum is hyperdynamic. MV mitral valve ; VS = ventricular septum; EGG . electrocardiogram; PHD = phonocardiogram.

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ECG Fig. 1. Aortic valve vegetations: The upper panel is from a patient with a fungal mass attached to the left coronary cusp which swept into the aortic orifice in systole. This large mass (2 X 1 em) had varied appearance depending on beam direction and phase of the cardiac cycle (see Fig. 2). The lower panel from another patient reveals a wide echo complex in diastole suggesting a large lesion. At surgery, scattered lmm calcified vegetations were presen t on all cusps and their echoes summate to produce this appearance. A V = aortic valve; EGG electrocardiogram.

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valve and large vegetations showed echocardiographic appearances of calcific aortic stenosis. and the other with a tricuspid aortic valve and perforation of one of the leaflets demonstrated appearances suggesting a bicuspid aortic valve with superimposed vegetations. Two patients had vegetations on both the aortic and mitral valves.

Mitral Valve

Fig. 2. Aortic-mitral sweep showing prolapse of aortic vegetations through the aortic valve and into the left ventricular outflow tract: In systole, with a high beam position, echoes from the vegetation appear contained by the aortic leafle ts. As the beam passes lower through the aorta the mass is demonstrated only in diastole as it descends into the left ventricular outflow tract. The posterior aortic wall is widened by a sinus tract. A V aortic valve; IVS interventricular septum; MV mitral valve; EGG electrocardiogram ; PHO Phonocardiogram.

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In 6 of the 11 patients vegetations were not identified echocardiographically although 2 patients demonstrated coarse systolic flutter of the right aortic leaflet secondary to perforation of the left aortic leaflet. Two patients had normal aortic valve echocardiograms in the presence of rupture of the right aortic leaflet but did show diastolic flutter of the mitral valve indicating the presence of aortic regurgitation. One of these patients also showed mitral valve preclosure. Of the 2 remaining patients. one with a bicuspid aortic

Of the 3 patients with mitral valve vegetations demonstrated surgically, 2 were correctly diagnosed echocardiographically. One of these patients later developed rupture of the chordae to both leaflets (Fig. 3). One patient with a 3mm vegetation on the posterior mitral valve leaflet and a calcified mitral valve annulus showed a normal anterior leaflet with a broad band of echoes behind the leaflet representing the calcified annulus. This broad band of echoes presumably obscured the vegetation . Three additional patients with mitral valve prolapse who subsequently developed bacterial endocarditis demonstrated a high frequency systolic flutter of the prolapsing segments (Fig. 4). Surgical proof is not yet available in these patients. The flutter is probably produced by structural abnormality of the mitral valve and resulting turbulence during mitral regurgitation.

Tricuspid Valve Although vegetations were present on the tricuspid valves of 2 patients at surgery, only in one of these patients was the tricuspid valve echo recorded. Dense echoes were seen behind the anterior leaflet in systole which correlated well with the surgical findings (Fig. 5). However, almost identical findings were seen in a patient with a small ventricular septal defect but a structurally normal tricuspid valve. This was the only false-positive echocardiogram.

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TABLE II:

Ultrasound

RESULTS OF lA..TRASONOGRAPHY

Affected valves Abnormal echocardiogram Vegetations correctly identified False positive

AORTIC

MITRAL

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5

2

2

1 1

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TRICUSPID

MV

, This figureincludes 3 patientswith mitral valve prolapseandsystolic flutter of the prolapsing segments Who have not yet required surgery.

Pulmonic Valve No vegetations were found on the pulmonic valve echocardiographically or at autopsy (5 patients). The pulmonic valve was not examined surgically in the remaining patients. These results are summarized in TABLE II.

ECG iiiiliiiiiiiiii Fig. 4. Mitral valveprolapse and bacterial endocarditis: A typical systolic abnormality of mitral valve prolapse is present along with a high frequency low amplitude flutter of the prolapsing segment: MV = mitral valve ; ECG electrocardiogram; PHD phonocardiogram.

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DISCUSSION Vegetations upon the aortic and mitral valves were first described echocardiographically by Dillon et al. (3) who detected nonuniform shaggy thickening of the affected valve leaflets in systole and diastole without restriction of the leaflet motion. Gottlieb et al. (4) added the presence of echoes in the left ventricular outflow tract due to prolapsing aortic valve vegetations. Similar findings were reported by Gramiak and Nanda (5), and Winsberg (16) . Lee et al. (7) described coarse systolic flutter of the aortic valve leaflets following rupture of an aortic leaflet secondary to bacterial endocarditis. An elegant study by Hirschfield and Schiller (6) localized the position of vegetations on each of the three aortic leaflets and confirmed the central position of the left coronary leaflet in the echocardiographic image of the aortic root. Wray (17) reviewed the echocardiographic features of aortic valve endocarditis. In addition we have seen localized thickening of the posterior aortic wall due to the presence of an abscess and sinus tract in a patient with fungal endocarditis (Fig. 1). In patients with mitral valve prolapse who developed bacterial endocarditis, Nanda et al. (11) described the appearance of a high frequency flutter of the prolapsing portion of the mitral valve leaflets. Mitral valve preclosure secondary to acute aortic regurgitation as a result of bacterial endocarditis was reported by Botvinick et al. (1) and DeMaria et al. (2). Left ventricular volume overload and other manifestations, other than vegetations, secondary to bacterial endocarditis were reported by Roy et al. (12). Vegetations on the tricuspid valve appearing as a mass of echoes behind the image of the anterior leaflet were seen by Lee et al. (8) and also by Wann et al. (15). Thus far, no vegetations have been detected on the pulmonic valve. Experience indicates echocardiography provides a useful method for detection of bacterial endocarditis but its sensitivity is not high (12, 15). There appear to be three major reasons for this lack of sensitivity. Firstly, certain areas of the heart and cardiac valves are difficult to image with single crystal echocar-

TV

PHO

ECG

Fig. 5. Tricuspid valve vegetations: The systolic segments of the tricuspid valve recording show a multilinear pattern and late systolic sagging . At surgery , a cluster of vegetat ions measur ing 3 mm in diameter was present on the leaflets at the po int of attachment of the chordae. The dense echo complex below the tricuspid valve originates in the atrial septum. TV tricuspid valve; ECG electrocardiogram; PHD phonocardiogram.

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diography. These include the left aortic leaflet, the posterior and septal leaflets of the tricuspid valve and the right and posterior leaflets of the pulmonary. In one of the patients in this study only the mitral valve echo could be recorded due to a very small cardiac window and lung interference . The development of two-dimensional echocardiography may overcome some of these deficiencies. Secondly, there is a high incidence of preexisting valve abnormalities in patients who develop infective endocarditis. In this study 6 (35 % ) patients had preexisting valvular disease and Roy et al. (12) found 44 % of their patients with preexisting valvular structural alterations. Certain of these abnormalities such as valvular calcification or myxomatous degeneration (3) may completely obscure the underlying vegetation. Thirdly, the vegetation may be too small or not arranged in a recognizable configuration. Others may be composed of elements which reflect sound so poorly that they are not detectable with current equipment. Nonspecific functional changes , such as echocardi-

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KENNETH R. THOM SON AND OTHERS

ographic evidence of aortic insufficiency, coarse systolic fluttering of aortic valve leaflets, flail mitral valve leaflets, left ventricular volume overload or isolated evidence of aortic wall thickening, may be used to support the clinical impression of bacterial endocarditis involving valves, especially if a previously normal echocardiogram is available. We have been unable, on a single echocardiogram, to distinguish acute active endocarditis from bacteriologically cured endocarditis. Similar opinions have been expressed by Wann et al. (15) and Roy et al. (12). In this study we also found echocardiography to be an unreliable indicator of the size of demonstrated vegetations (Fig. 1). In conclusion, echocardiography is capable of detecting a significant percentage of vegetations in infective endocarditis and is also useful in the detection of preexisting disease and the nonspecific manifestations of infective endocarditis. It is therefore valuable in the management of patients with infective endocarditis. ACKNOWLEDGMENTS: The authors wish to thank Ben Emerson and Margaret Kowaluk for their assistance in the preparation of this manuscript. Raymond Gramiak, M.D. Department of Radiology University of Rochester Medical Center P.O. Box 648 601 Elmwood Avenue Rochester, New York 14642

REFERENCES 1. Botvinick EH, Schiller NB, Wickramasekaran R, et al: Echocardiographic demonstration of early mitral valve closure in severe aortic insufficiency. Its clinical implications. Circulation 51:836-847, May 1975

November 1977

2. DeMaria AN, King JF, Salel AF, et al: Echography and phonography of acute aortic regurgitation in bacterial endocarditis. Ann Intern Med 82:329-335, Mar 1975 3. Dillon JC, Feigenbaum H, Konecke LL, et al: Echocardiographic manifestations of valvular vegetations. Am Heart J 86: 698-704, Nov 1973 4. Gottlieb S, KhuddusSA, Balooki H, et al: Echocardiographic diagnosis of aortic valve vegetations in candida endocarditis. Circulation 50:826-830, Oct 1974 5. GramiakR, NandaNC: Mitral valve. [In] CardiacUltrasound, Gramiak R, Waag RC, eds. St. Louis, C. V. Mosby Co., 1975, pp 54-68 6. Hirschfield DS, Schiller N: Localization of aortic valve vegetations by echocardiography. Circulation 53:280-285, Feb 1976 7. Lee CC, Das G, Weissler AM: Characteristic echocardiographic manifestations in ruptured aortic valve leaflets (abst). Circulation 50(Suppllll):144, 1974 8. Lee CC, Ganguly SN, Magnisalis K, et al: Detection of tricuspid valve vegetations by echocardiography. Chest 66:432-433, Oct 1974 9. MartinezEC,Burch GE, GilesTO: Echocardiographic diagnosis of vegetative aortic bacterial endocarditis. Am J Cardiol 34:845-849, Dec 1974 10. Myer JF, Frank MJ, Goldberg S, et al: Systolic mitral flutter: An echocardiographic clue to the diagnosis of ruptured chordae tendinae (abst). Clin Res 23:197A, 1975 11. NandaNC, Gramiak R, ManningJA: Echocardiographyof the tricuspid valve in congenital left ventricular right atrial communication. Circulation 51:268-272, Feb 1975 12. Roy P, Tajik AJ, Giuliani ER, et al: Spectrum of echocardiographic findings in bacterial endocarditis. Circulation 53:474-482, Mar 1976 13. Schelbert HR, Muller OF: Detection of fungal vegetations involving a Starr-Edwards mitral prosthesis by means of ultrasound. Vasc Surg 6:20-25, Jan-Feb 1972 14. Spangler RD, Johnson ML, Holmes JH, et al: Echocardiographic demonstrations of bacterial vegetations in active infective endocarditis. J Clin Ultrasound 1:126-128, Jun 1973 15. Wann LS, Dillon JC, Weyman AE, et al: Echocardiography in bacterial endocarditis. N Engl J Med 295:135-139, 15 Jul 1976 16. WinsbergF: Aortic valve. [In] Cardiac Ultrasound. Gramiak R, Waag RC, eds. St. Louis, C. V. Mosby Co., 1975, pp. 82-83. 17. Wray TM: The variable echocardiographic features in aortic valve endocarditis. Circulation 52:658-663, Oct 1975