Case report
Ring annuloplasty and successful mitral valve repair in a staphylococcal endocarditis case with bilobular saccular mycotic aneurysm at cerebral artery and frontal region infarction. Secondary to septic emboli

Introduction
The investigation and management of infective endocarditis in the developed world have changed radically over the past 30 years [1, 2]. Non-invasive imaging, molecular science, diagnostic protocols, and curative surgery have all become commonplace, yet the incidence remains unchanged and annual mortality approaches 40% [3]. Cardiac complications of IE develop at valves or the perivalvular region. In association with tissue loss, staphylococcus frequently causes tear, erosion, perforation and calcific depositions at leaflets. Non-cardiac complications include emboli due to vegetations. Left-sided endocarditis can be complicated with brain, kidney, spleen and intestine infarction and/or systemic embolism associated with mycotic arterial aneurysm or abscess [4]. In active IE cerebral signs are more prominent than visceral signs and embolism is the most frequent (22 to 43%) complication, closely related to prognosis [4, 5]. Surgery is needed in approximately 50% of patients who develop infective endocarditis, and careful timing is essential to ensure a good outcome [1]. In this article, we present our diagnostic approach and mitral valve repair technique in a MSCONS IE case with two rare cerebral complications.
Case report
Our patient was a 53-year old man. Six months before referring to our clinic for operation, he was admitted to another hospital for loss of appetite, weight loss and weakness. Diagnosis was pyelonephritis and parenteral antibiotherapy and outpatient clinic control was recommended for mitral valve prolapsus and 3° regurgitation. In the next three months he lost 20 kg and malign factors were investigated in another institute. His pathology results were: ESR 103 mm/hour, haematocrit 30.2%, CRP 24 mg/l and erythrocytes were hypochromic and microcytic. The transthoracic echocardiography (TTE) showed that his mild mitral regurgitation progressed and a 15 × 20 mm mobile vegetation developed at the posterior mitral leaflet. Also, mitral maximum gradient secondary to mitral regurgitation increased to 18.2 mm Hg (Figure 1). Diameter of left atrium (42 mm) and left ventricle (50/35 mm) were widened. Left ventricle EF was 60%. Pulmonary arterial pressure was 45/19 mm Hg and echocardiographic score was found to be 9. There was 1-2° tricuspid regurgitation. Other valves’ functions were normal. He was in New York Heart Association (NYHA) functional class III-IV at presentation. He was hospitalized urgently in our Cardiology Clinic due to those subacute infective endocarditis symptoms. After emergent Infectious Disease consultation 24 millionU/day crystalline penicillin and 160 mg/day parenteral gentamicin were started. Two days later haemoculture was positive for MSCONS and drugs were replaced with ceftriaxone 3 g/day + gentamicin 160 mg/day. Brucella and salmonella serological tests were negative. His fever persisted at 38.3°C and treatment was changed to 4 × 500 mg/day imipenem + rifampicin 1 × 600 mg/day. When the 6th week of the last parenteral antibiotherapy ended, vegetation diameter did not improve in weekly echocardiographic controls, and ESR was 65 mm/hour, CRP was 9.6 mg/l and WBC was 8600. He went under operation. His coronary arteriography was normal. Further investigations with cerebral MR angiography showed bilobulated saccular aneurysm at left middle cerebral arterial bifurcation level, which was consistent with mycotic aneurysm secondary to septic embolization (Figure 2). In addition, multiple infarction images characterized by gyral thickness and oedema in the left posterior frontal region and vertex level could be consistent with the same aetiology (Figure 3). Neurochirurgical consultation did not recommend emergent surgery. Outpatient clinic control was recommended after the IE treatment ended. Thorax and abdominal CT and MRI were normal. He was operated on under endotracheal general anaesthesia and in the supine position. Following a median sternotomy, the pericard was opened longitudinally. After heparinization, extra-corporeal circulation was established between the venae cavae and the ascending aorta. A cross clamp was placed on the aorta and by antegrade intermittent isothermic blood cardioplegia from the aortic root, cardiac arrest was established. Hypothermia was moderate (28°C). A vent was placed via the right superior pulmonary vein. Standard left atriotomy was made from the interatrial junction. The mitral valve was approached via a standard left atriotomy parallel to the interatrial sulcus. Cooley’s retractor was positioned for optimal exposure. The entire valvular apparatus was carefully examined in order to assess the feasibility of reconstructive surgery and to plan the operative technique. The valvular apparatus was then mobilized as an entire unit with a nerve hook in order to assess tissue flexibility and to identify leaflet restriction. There were vegetative formations on a torn basal chorda in the posterior leaflet P1 region near the anterolateral commissure (Figure 4). In the A2 region of the anterior leaflet there was calcific formation, extending to the left atrium and limited to the endocardial layer of the leaflet (Figure 5). Calcific vegetative formation of the anterior leaflet was stripped without harming the leaflet. Vegetation in the posterior part was extirpated with broken basal chordae extensions. Chordae counts of both anterior and posterior leaflets were sufficient. Because of resected posterior leaflet’s chordae, unilateral segmental annuloplasty was performed to the posteromedial commissure. This procedure may also be used to achieve better approximation of leaflet tissue with the placement of mattress stitches at the commissures. We tested the valve competence after this step on observing valve closure while the left ventricular cavity was filled with saline solution. There was no saline regurgitation. From a surgical point of view, a flexible ring reduces the tension of the sutures, decreasing the likelihood of ring dehiscence. The ring can also be split. This is particularly useful in those cases in which the surgeon doubts the quality of the repair. For these reasons we performed mitral ring annuloplasty with H608H31 Duran flexible ring model H608H, 31 mm. We re-tested the valve competence after this step on observing valve closure with saline solution. Valve competence and closure were excellent (Figure 6). Left atriotomy was closed in standard fashion. Postoperative rhythm was sinusal. He did not require inotropic support during weaning from cardiopulmonary bypass and early postoperative period. The volume of blood transfused was 2 units. The quantity of mediastinal drainage was 450 cc. He was extubated after intubation of 6 hours duration and stayed in intensive care for 2 days. The hospital stay was 10 days. Infectious Disease consultation recommended 10 more days of oral 1 × 400 mg/day cefixime after discharge. Chest X-ray showed optimal configuration of the ring (Figure 7). Postoperatively on the discharge day and after 2 months an echocardiographic investigation revealed minimal non-significant regurgitation for the repaired mitral valve (Figure 8). Postoperatively, the mitral valve area was found to be 3.76 cm2 by pressure half-time echocardiography (Figure 9). The mean gradient of the mitral valve was 4.42 mm Hg. The functional capacity of our patient improved dramatically and he was in NYHA functional class I. We found no postoperative cardiac decompensation symptoms in our patient during late follow-up and he was followed at our outpatient clinic without additional problems.
Discussion
The incidence of infective endocarditis is approximately 1.7-6.2 cases per 100 000 patient years [6]. Patients can have severe cardiac injuries after infective valve endocarditis. Staphylococcal IE is a severe, life-threatening infection and makes up 1/3 of all IE cases [7]. Staph. aureus is one of the most tissue-injuring bacteria along with Serratia sp, Pseudomonas sp, Brucella and Candida sp. If staphylococci are the aetiological agent of the infection, surgery requirement increases and prognosis is poor due to high virulence, severe intracardiac injury and frequent embolic complications [8]. The need for robust diagnostic criteria uniting these means of investigation was shown by the original Von Reyn criteria, published in the early 1980s and subsequently superseded by the Duke criteria in the 1990s in the light of improved echocardiographic techniques [9]. Despite the high sensitivity and specificity of these original criteria, subsequent modifications have been suggested to acknowledge the increasing prevalence of staphylococcal infection. These modified Duke criteria have now been adopted in the latest guidelines from the European Society of Cardiology [1, 10]. Given the need for prolonged antibiotic treatment in most patients with infective endocarditis, positive microbiological cultures and sensitivities are vitally important for successful management [1]. Current guidelines recommend that three sets of blood cultures are drawn one hour apart before the introduction of antibiotic treatment – the first two sets are positive in more than 90% of cases [10]. Vegetations can be determined in 13 to 78% during IE attacks with echocardiography and clinical symptoms are found in 10 to 50% [11]. Emboli risk is 5 times higher in native mitral valve endocarditis [12]. Necropsy studies showed that embolization rate is 60% in kidney, 44% in spleen, 40% in brain and 30% in coronary arteries [11]. Many established series had 2 to 3 times higher embolic complication rate with staphylococcal IE than other aetiologies [12]. Recent studies did not confirm the value of echocardiography for embolism [13]. Still, >15 mm vegetation, determined with echocardiography at any location, is a definite embolism indicator [11]. In addition to morphology, mobility, persistence and rapid enlargement of the vegetation are absolute embolism risk factors [13]. According to our clinical approach we used antibiotic treatment for 6 weeks in endocarditis originated mobile masses and waited for at least 7 to 10 days without fever. But if a micro/macro embolus clinical table is seen during antibiotherapy in the lower or upper leg or cerebrum we prefer surgery although it is risky. Surgery is often difficult and associated with high risk, not least because patients are frequently extremely sick with multisystem disease [1]. The first surgical treatment was performed in 1965 in an active IE patient and became effective in time [14]. Surgery is obligatory in at least 30% of active IE patients and in another 20 to 40% after healing [15]. From the 1970s, reconstructive surgery of the mitral valve was implanted definitively after the pioneering work of Carpentier [16]. Since then, clinical experience has shown that this conservative surgery involves minor hospital mortality and more satisfactory long-term clinical results [17]. Advantages of mitral valve repair in native mitral valve endocarditis are shown at Table I. Mitral valve reconstructive surgery without annuloplasty entails a high incidence of early failures [18]. The objectives of annuloplasty are: 1) to correct the annular dilatation, 2) to increase free edge coaptation, 3) to reinforce the annulus after a leaflet resection procedure, and 4) to prevent further annular dilatation. Flexible ring annuloplasties were introduced based on the principles of mitral valve reconstruction introduced by Carpentier, particularly after the discovery of the three-dimensional continuous movements of the valve annulus. A completely flexible Duran ring reduces the abnormally dilated annulus, allowing three dimensional configuration of the mitral valve, and it was thought to be advantageous that the ring followed the changes of size and shape of the atrioventricular annulus in a physiological manner. Because our clinical results are consistent with the literature we prefer flexible rings instead of rigid or autologous pericardium. In conclusion today operational mortality of 4 to 30% is an acceptable level. Five-year survival rate was 54% with medical treatment and 75% with medical and surgical combination [19]. Mitral valve endocarditis and MSCONS infections are the negative factors for long-term survival. As in our case, medical treatment protocol and elective surgery after control of infection decrease the short-term mortality and morbidity risk significantly.
References
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