Prosthetic valve endocarditis presenting as loss of the metallic click sound.

Abstract: Prosthetic valve endocarditis is a significant infection. It is often serious, and may result in a complicated course leading to valvular malfunction. We present the case of a 50-year-old male with an aortic Medtronic Hall valve, who presented with loss of his normal metallic click. A transthoracic echocardiogram confirmed the diagnosis of endocarditis and of an aortic-root abscess. Blood cultures were positive for nutritionally deficient Streptococcus. He underwent successful surgery and later was discharged. Patients with mechanical heart valves are often bothered by the metallic sound. It can interfere with their daily life. However, the loss of the click may indicate valvular dysfunction, dehiscence of the prosthesis, and/or tissue infection with abscess formation.

Key Words: endocarditis, mechanical heart valve, metallic click, valve malfunction

**********

Sixty-five to seventy-five percent of patients with mechanical heart valves are disturbed by the metallic clicks, the Edwards-Duromedics valve (Baxter-Edwards, Inc., Santa Ana, CA) being the loudest. (1) Prosthetic valve endocarditis (PVE) is not uncommon, and often has consequences leading to valve malfunction. Patients with PVE present with symptoms and signs similar to native valve endocarditis, ie, fever, new or changing heart murmur, electrocardiographic conduction disturbances, and positive blood cultures. However, the presentation can be subtle, and as a result, delay the diagnosis and treatment. We report a case of PVE in which loss of the normal valvular click was the main presenting feature.

Case Report

A 50-year-old Hispanic male with history of hypertension, intravenous drug abuse, alcohol abuse, and hepatitis C, presented to our hospital with a 2-day history of chills and shortness of breath. He denied any chest pain, fever, or cough. He had had his aortic valve replaced with a Medtronic Hall prosthetic valve (Medtronic Inc., Minneapolis, MN) 4 years prior because of complicated endocarditis secondary to dental sepsis. On physical examination, he was afebrile with a pulse rate of 90 bpm and a blood pressure of 123/70 mm Hg. He had an audible click before auscultation. His heart examination revealed a previously noted apical systolic murmur radiating to the axilla. His lungs were clear and his abdomen was normal. There was no evidence of digital emboli.

His blood count showed anemia without leukocytosis. The electrocardiogram (ECG) revealed a normal sinus rhythm, and the chest radiograph demonstrated a right lower lobe infiltrate.

He was started on clindamycin for a presumed aspiration pneumonia. However, on hospital day 2, he had a temperature of 103[degrees]F, and on day 3 he complained, "my click is gone." Physical examination revealed rales at both lung bases and a new diastolic murmur at the aortic site, with absence of the metallic click. Transesophageal echocardiography confirmed the presence of an aortic root abscess, and blood cultures grew nutritionally deficient Streptococcus. A subsequent EKG revealed a third-degree atrioventricular block. He was then transferred to the cardiothoracic intensive care unit, and later underwent drainage of the abscess with an aortic valve replacement. He was discharged 3 weeks later.

Discussion

About 60,000 heart valve replacements are performed each year in the United States. (2) More than 60% of these procedures use mechanical valves. There are two major categories of mechanical heart valves, the caged-ball and the tilting-disc valves. The Medtronic Hall valve is a tilting-disc that has a titanium housing and a carbon-coated disc. The disc is normally retained in the housing and guided during opening and closing by a strut that protrudes through a central hole in the disc. The type of complications associated with prosthetic heart valves can range from structural failure to valvular obstruction and thrombosis, pannus formation, systemic embolization, bleeding, disturbing click sound, and infection. (2-4) The metallic click sound created by the prostheses frequently bothers patients and can impact their quality of life. (5,6) In fact, one study showed that the intensity of the closing click correlates to the patients' complaints. (1) Furthermore, complaints were related to the objectively measured sound pressure, which varied with the different prostheses' designs. (7) Though our patient was not bothered by the click sound, he was constantly aware of its presence. It was the disappearance of the click that concerned him.

Prosthetic valve endocarditis and other infections are not unusual, and their risk may approach 1% per year (a rate similar to the bioprosthetic valve). (8) They are typically associated with valve ring and myocardial abscesses, and are usually located in the sewing ring, causing detachment, leak, and valvular malfunction. Large vegetations may prevent closure of the prosthesis, producing incompetence and disappearance of the click, with annular abscesses being more common in aortic valves. (9) In 1965, Spencer et al described a case of acute mitral valve obstruction from extensive thrombosis of a Starr-Edwards prosthesis (Baxter Healthcare, Edwards CVS Division, Santa Ana, CA), diagnosed by a finding of an absent prosthetic click. (10) And in 1970, Cheng et al reported a fatal clotting of a similar valve that was detected by the disappearance of a clicking sound. (11) However, in both cases the absence of the click was determined on physical examination, and was not a complaint of the patients.

Similar to the case reported here, patients with infective endocarditis may present with a constellation of clinical findings, including fever, new murmurs, positive blood cultures, and ECG changes. However, the disappearance of a click, a symptom that has not been frequently mentioned in the literature as a presenting feature of infective endocarditis, may signal valvular dysfunction, infection, or dehiscence of the prosthesis. Our patient had fever and shortness of breath at presentation that were attributed to pneumonia, but it was not until the metallic click disappeared that a diagnosis of endocarditis was entertained.

Conclusion

Prosthetic valve endocarditis is a serious disease and may lead to complete malfunctioning of the cardiac valve. The presentation can be subtle, causing a delay in the diagnosis. The disappearance of the click may also be a presenting feature of endocarditis, signaling valve dysfunction, prosthesis dehiscence, or abscess formation. Patients concerned about the click sound should be reassured that it may reflect normal function of their valve. While the metallic sound can be disturbing to patients, the loss of the click can be disturbing to their health.

Acknowledgments

We would like to acknowledge the following physicians for their contribution in preparing this manuscript: Stephen Atlas, MD, Norman Marieb, MD, and Barry Wu, MD.

Accepted July 7, 2004.

References

1. Moritz A, Steinseifer U, Kobina G, et al. Closing click of St Jude Medical and Duromedics Edwards bileaflet valves: complaints created by valve noise and their relation to sound pressure and hearing level. Eur Heart J 1991;12:673-679.

2. Vongpatanasin W, Hillis LD, Lange RA. Prosthetic heart valves [see comments]. N Engl J Med 1996;335:407.

3. Hammermeister KE, Sethi GK, Henderson WG, et al. The Veterans Affairs Cooperative Study on Valvular Heart Disease: a comparison of outcomes in men 11 years after heart-valve replacement with a mechanical valve or bioprosthesis. N Engl J Med 1993;328:1289-1296.

4. Akins CW, Mechanical cardiac valve prostheses. Ann Thorac Surg 1991;52:161-172.

5. Bloome-Eberwein SA, Mrowinski D, Hofmeister J, et al. Impact of mechanical heart valve prosthesis sound on patient's quality of life. Ann Thorac Surg 1996;61(2):594-602.

6. Sezai A, Shiono M, Orime Y, et al. Evaluation of valve sound and its effects on ATS prosthetic valves in patients' quality of life. Ann Thorac Surg 2000;69:507-512.

7. Moritz A, Steinseifer U, Kobinia G, et al. Closing sounds and related complaints after heart valve replacement with St Jude Medical, Duromedics Edwards, Bjork-Shiley Monostrut, and CarboMedics prostheses. Br Heart J 1992;67:460-465.

8. Bloomfield P, Wheatley DJ, Prescott RJ, et al. Twelve-year comparison of a Bjork-shiley mechanical heart valve with porcine bioprostheses. N Engl J Med 1991;324:573-579.

9. Baumgartner FJ, Omari BO, Robertson JM, et al. Annular abscesses in surgical endocarditis: anatomic, clinical and operative features. Ann Thorac Surg 2000;70:442-447.

10. Spencer FC, Trinkle JK, Reeves, JT. Successful replacement of a thrombosed mitral ball valve-prosthesis. JAMA 1965;194:1249-1251.

11. Cheng TO, Kinhal V, Tice DA: Fatal thrombosis of the Starr-Edwards mitral valve prosthesis associated with the bacterial endocarditis. Diagnostic significance of a disappearing prosthetic click. Chest 1970;57:151-155

RELATED ARTICLE: Key Points

* Infective endocarditis of a mechanical heart valve is a grave disease and may lead to malfunction of the valve.

* The presentation of endocarditis can be subtle, resulting in a delayed diagnosis.

* The metallic clicking sound produced by a mechanical valve frequently bothers patients and can interfere with their quality of life.

* The loss of the clicking sound can be a serious presenting symptom of endocarditis, and may indicate valvular dysfunction and tissue extension of the infection.

Antoine G. Sreih, MD, and Rahul Mehta, MD

From the Yale University School of Medicine, and the Departments of Medicine and Radiology, The Hospital of Saint Raphael, New Haven, CT.

The authors have no financial, commercial or proprietary interests in any drug, device, or equipment mentioned in this article.

Reprint requests to Antoine G. Sreih, MD, Medical Director, Department of Medicine, The Hospital of Saint Raphael, 1450 Chapel Street, New Haven, CT 06511. Email: [e-mail]