Incidental Diagnosis of Healed Aortic Abscess Cavity

In infective endocarditis, the perivalvular abscess is a known complication with an incidence of more than 22%-29%, but the primary presentation of a healed aortic abscess without any clinical features of infective endocarditis is very rare. These sorts of cases are scarcely documented throughout literature. We present a successful surgical closure of healed perivalvular abscess cavity with aortic valve replacement and mitral valve repair.


Introduction
A perivalvular abscess is a known complication of infective endocarditis (IE) with an incidence of around 22%-29% [1,2]. Silent presentation of IE with a healed aortic abscess is very rare, with seldom documented cases throughout literature. Initially, two-dimensional echocardiography has shown to be useful in the diagnosis of abscess cavities. Due to the proximity of transesophageal echocardiography (TEE) probe to the aortic valve (AV) and higher signal-to-noise ratio, TEE was found to be a superior imaging modality in comparison to transthoracic echocardiography (TTE) [3,4]. IE usually presents with symptoms of fever, myalgia, flu-like symptoms, fatigue, chest pain, and signs like heart murmurs, anemia, or embolic events. Our patient presented with only complaints of breathlessness without any other clinical evidence of IE. Intraoperative TEE accidentally picked a rare healed aortic abscess cavity with a floor formed by the left atrium. We report a successfully performed direct closure of a healed perivalvular abscess cavity by including the cavity during AV implantation within the suture line itself.

Case Presentation
A 44-year-old gentleman presented with complaints of shortness of breath of 30 days' duration. On initial evaluation, his heart rate was 72 beats/min, blood pressure was 120/40 mmHg and he was afebrile. We found an early diastolic murmur in the aortic area and a pansystolic murmur in the mitral area. Electrocardiography (ECG) was suggestive of left ventricular (LV) hypertrophy and left atrial enlargement ( Figure 1).    No history and clinical features suggestive of IE were found. Hematological and biochemical markers of endocarditis like total leucocyte count (7,300 cells/mm 3 ) and erythrocyte sedimentation rate (8 mm/hr) were within the normal range.
Intraoperative TEE examination showed that the AV is trileaflet with severe AR and showed a cavity ( Figures  6A, 6B) near the non-coronary cusp -left coronary cusp (NCC-LCC) commissure extending to the base of anterior mitral leaflet and moderate MR. Three-dimensional (3D) TEE with the multi-beta acquisition with six ECG beats stitched together was done, which confirmed the same findings. Post sternotomy and pericardiotomy, we found a hugely dilated heart with moderate dilatation of the aorta. Cardiopulmonary bypass (CPB) was instituted using aorto-bicaval cannulation. Hypothermic Delnido cardioplegia was used for diastolic cardiac arrest. After aortotomy, we found a tricuspid AV with thickened and tethered non-coapting cusps. A healed aortic abscess cavity 1 * 1 * 0.5 cm was seen at the NCC sinus close to NCC-LCC commissure (Figure 7).   The patient's course in the hospital was uneventful. The patient was discharged with antiplatelet, anticoagulant (with target international normalized ratio -2.5-3.5), and eight weeks of antibiotic course prophylactically (as per our infectious disease physician's advice).

Discussion
A paravalvular abscess usually presents as persistent fever, despite appropriate antibiotic therapy, or as a new conduction abnormality as the abscess erodes into adjacent cardiac conduction tissue. Our patient had none of the above symptoms and there was no other history suggestive of IE and presented with a healed abscess cavity, sequelae of IE.
The algorithm proposed by the European Society of Cardiology, The Task Force on the Prevention, Diagnosis, and Treatment of IE recommends TEE in patients with high clinical suspicion of IE along with a normal TTE. TEE is always recommended even when the diagnosis is made, as TTE has the better image quality and sensitivity predominantly for perivalvular involvement. With better quality, negative TTE, and low clinical suspicion of IE, only TTE may be considered satisfactory. Intraoperative TEE is recommended in all patients of IE undergoing surgery [5]. We did not do a pre-operative TEE assessment, as the patient presented devoid of any IE features.
As an institutional policy, we electively do TEE for all patients with valvular abnormalities. 3D TEE with the multi beta acquisition is also done, as it gives a more defined quality of images.
The various procedures involved in the repair of aortic abscess included AV replacement with pericardial patch closure of the cavity, annular reconstruction, Bentall's procedure, and other aortic root replacement surgeries.
This case had a healed abscess detected incidentally and a similar case was reported once by Datt et al. where they detected on intraoperative TEE where two healed abscesses were noted. The first was at the NCC-LCC commissure and the other on top of the right coronary cusp. The patient had AV (25 mm mechanical valve) and ascending aorta (26 mm Dacron graft) replacement under standard CPB technique [6].
In our patient, the healed abscess cavity was obliterated by including it in the suture line and plicated along with the AV, without using any patching material. It is always good to avoid prosthetic materials, as the chance for reinfection is high. Croon et al., while analyzing the outcome of AV endocarditis with periannular abscess, has found that the mean aortic cross-clamp time was 110±40 minutes and mean bypass time of 157±70 minutes [7]. Our technique has reduced the aortic cross-clamp and bypass time. The pre-requisite to our technique is that cavity should be nearer to the aortic annulus and should not be too deep. If any suspicion of infection there, then the cavity should be left open.
The left atrial musculature was seen on the floor of our abscess cavity. This shows that on the progression of the abscess it would have developed into a ruptured sinus of valsalva (RSOV) into the left atrium. RSOV rupturing into the left atrium is itself an extremely rare presentation.