Junyang Lou, MD, PhD
A 58 year old obese male is referred to the Cleveland Clinic due to worsening fatigue, dyspnea on exertion and chest discomfort. He underwent mitral valve replacement one year prior for flail posterior mitral valve leaflet, receiving a #29 St. Jude EPIC Ô bioprothesis. His post operative course was complicated by sternal wound infection and atrial fibrillation requiring AF ablation, from which he eventually recovered. He was finally feeling well 5 months after cardiac surgery and able to exercise daily. Over the last several months, however, he noticed progressive intense fatigue, SOB and neck and shoulder pressure. On several occasions he felt he might pass out. Pulmonary hypertension was diagnosed by his physicians and he elected to be referred to us for a second opinion. He denies fevers, chills or chest pain.
Past Medical History
The patient has long-standing obstructive sleep apnea (OSA) and has been using nocturnal CPAP therapy for the last 10 years. He also has coronary artery disease and received a drug-eluting stent to the left anterior descending coronary artery in 2007. He has remote smoking history and does not drink alcohol.
Initial Physical Exam
The patient was afebrile with blood pressure 132/76 mmHg, HR 41 bpm. He was obese and in no distress. His surgical scar was well healed without tenderness or fluctuance. He had good dentition and no lymphadenopathy. Jugular venous pulsation was elevated at 14 cm with the patient upright. Lungs were clear to auscultation. Cardiac exam is notable for bradycardia and a soft holosystolic murmur which intensified with handgrip. He had normal peripheral arterial pulses and there was no pitting edema.
Diagnosis/Treatment prior to presentation at Cleveland Clinic
The patient presented to local emergency room a week prior to arrival for neck, shoulder and arm pressure. He felt as though he was going to pass out. He had a CT angiogram of the chest that was negative for PE and and a transthoracic echo found pulmonary hypertension. His valve had been evaluated one month after replacement by transesophageal echo, and he was told “it was fine”.
Diagnosis/Treatment upon presentation at Cleveland Clinic
An EKG was obtained and revealed sinus bradycardia without evidence of infarct or ischemia. A chest X-ray revealed post-sternotomy status with cardiomegaly and no evidence of pulmonary infiltrates. A transthoracic echo (TTE) was repeated and this revealed normal left and right ventricular systolic function with estimated pulmonary artery PA pressure of 75mmHg. There was mild mitral regurgitation (MR) with elevated gradient across the MV, suggesting prosthetic mitral stenosis (peak/mean gradient 44/12mmHg). Peak mitral velocity was elevated at 3.3 m/s (reference 0.62m/s) and velocity time integral (VTI) was elevated at 162 cm (see figure). A transesophageal echo performed the next day confirmed severe MR due to perforation of the anterior prosthetic valve leaflet. There also was a mobile echodensity attached to the anterior aspect of the valve struts/cage, measuring 0.6 cm, which is suspicious for vegetation.The patient also underwent coronary angiography, which revealed patent stent in the LAD and mild CAD.
The patient was taken to operating room. After re-do sternotomy, the prosthesis was found to have 5x8mm perforation in the anterior leaflet (see figure). A Biocor® #31 valve was used to replaced the original prosthesisand his PA pressure decreased to 42mmHg 2 weeks post-op. The explanted prosthesis eventually grew Propiobacterium acnes, for which the patient was treated with long term antibiotic therapy. He had an unremarkable recovery and remains on nocturnal CPAP therapy for OSA.
This patient was referred for treatment of pulmonary hypertension and was found to have severe prosthetic mitral valve regurgitation from subacute bacterial endocarditis from P. acnes. In patients with dyspnea and pulmonary hypertension, mitral valve dysfunction should be excluded especially in the setting of preserved left ventricular function and recent valve surgery.1 While significant mitral disease was not evident on TTE, the diagnosis was suspected due to elevated transmitral forward flow volume and velocity, which strong suggests prosthetic MR.2 TEE, the gold standard modality for the diagnosis of prosthetic mitral regurgitation3-4, provided confirmation and mechanism of valve dysfunction.
Comment by Dr. Jim Thomas: There are several interesting aspects to this case. Although Propiobacterium acnes is a common pathogen for skin lesions, it is only rarely the cause of endocarditis. When this does occur, it is usually in the setting of a prosthetic valve, as in this case. Interestingly, this patient’s severe mitral regurgitation was not very evident by transthoracic echo, with the jet likely obscured by shadowing from the valve ring and struts. One important clue was the finding of a very high peak gradient with a relatively low mean gradient. This combination should always prompt investigation for occult severe MR, which was clearly demonstrated by transesophageal echo. While prosthetic valve endocarditis can sometimes be treated medically, in the setting of severe enough regurgitation to cause pulmonary hypertension, there is no alternative to surgery.
1. Alexopoulos D, Lazzam C, Borrico S, et al. Isolated chronic mitral regurgitation with preserved systolic left ventricular function and severe pulmonary hypertension. J Am Coll Cardiol. 1989;14(2):319.
2. Olmos L, Salazar G, Barbetseas J, et al. Usefulness of transthoracic echocardiography in detecting significant prosthetic mitral valve regurgitation. Am J Cardiol 1999;83:199–205
3. Shah A, Kronzon I. The enigma of occult mitral regurgitation in a patient with cardiogenic shock. Am Soc Echocardiogr. 2003;16(10):1080-1.
4. Rahko PS.Assessing prosthetic mitral valve regurgitation by transoesophageal echo/Doppler. Heart. 2004; 90(5): 476–478.
A. Apical 4-chamber view of TTE demonstrating lack of significant MR during systole
B. Continuous-wave(CW) Doppler recording through mitral valve with elevated flow velocity and volume
C. Longitudinal plane of TEE with jet of MR
D. Intraoperative photograph of bioprosthetic mitral valve with perforation of the anterior leaflet