PVE is the most severe form of infective endocarditis (IE) and occurs in 1–6% of patients with prosthetic heart valves. The incidence was reported as 0.3–1.2% patient-year. Endocarditis that develops within the first 1 year after surgery is defined as early PVE.
In early PVE, microorganisms are acquired either intraoperative during valve replacement or often during nosocomial bacteremia. Microorganisms acquired in this way can settle in the ring and sutures of the prosthetic valve, spreading to the tissues around the valve and leading to the development of complications such as PA. Reported risk factors for PA development include being a hemodialysis patient, having staphylococcal endocarditis, prosthetic valve endocarditis, i.v. drug use, presence of an annular ring, and aortic valve involvement. . The risk factors we identified in our case were iv drug addiction and IE affecting the aortic valve.
The most common factors in early PVE are S. aureus, coagulase-negative Staphylococcus, non-HACEK Gram-negative bacillus, and fungi including mainly Candida spp. [2–3]. In our case, blood cultures taken from both arms of our patient were found to be sterile during his application to the hospital. The reason for this situation may be related to the continued use of iv antibiotics after the patient is discharged.
Although the diagnosis of PVE is usually based on TTE and blood culture results, both of these can be negative in PVE. In determining vegetation and abscesses in PVE patients, TTE sensitivity was reported as 29% and 36%, respectively, while TEE sensitivity was reported as 82% and 86%, respectively . Therefore, TEE should be done on patients where TTE is negative or suspicious. In our case, after the TTE images were found suspicious and the blood culture results were found negative, TEE was performed and paravalvular septate abscess with a thickness of 1.4 centimeters was detected in the widest part surrounding the prosthetic aortic valve.
In cases where PA develops after PVE, the clinical manifestation is variable. Patients may be asymptomatic or have the symptoms of resistant fever or abscess diffused to the perivalvular tissues. In the literature, it has been reported that there is a relationship between the presence of newly developed AV blocks and the development of abscesses. Close ECG monitoring is recommended at the time of the patient's admission and during treatment, especially in aortic valve endocarditis and in patients at risk of developing periannular complications [5–6]. Our patient did not have a fever, but the newly developed complete AV block was present. In addition, the color Doppler examination, which wraps the mechanical aortic valve around the body, showed an image compatible with the abscess in which there was no current, although there were no septic symptoms. It was also noteworthy that there were septations in the abscess.
In IE, in which a heart block develops, causing a paravalvular abscess or destructive lesions, early surgical treatment should be performed on the patient, regardless of whether antibiotic treatment is completed. The more the infection has spread, the greater the need for allograft use. Especially in the presence of aortic root abscess, homografts or xenografts without stents may be preferred in cases where the aorta-ventricular junction is affected and in prosthetic aortic valve endocarditis [7–8].