Potential chronic abscess cavity that masqueraded as sinus of Valsalva aneurysm: is TEE a vital tool?

A 76 year old gentleman was scheduled for elective cardiac surgery for the repair of a sinus of Valsalva (SV) aneurysm. The relevant clinical history revealed a New York Heart Association (NYHA) grade 2 dyspnoea and minimal chest discomfort. Additional comorbidities comprised of controlled Type II diabetes mellitus, mild renal impairment, childhood history of rheumatic fever and present day cigarette smoking. He was operated for transitional cell carcinoma of bladder 4 years back, with no recurrence and on regular follow-up.

He had suffered from fever with rigors about 8-10 weeks before this elective admission. This episode of pyrexia was not associated with any respiratory, urinary or dental symptoms.

It was regarded as flu-like and he recovered by taking paracetamol for couple of days. He had no known drug allergies and his regular medications included metformin, bisoprolol and aspirin, the last one being discontinued 5 days prior to the surgery. On examination, this gentleman was 174 cm tall and weighing 83 kg with a body mass index of 27. His cardiovascular and respiratory parameters were normal and a systolic murmur was heard in aortic area on auscultation, consistent with the diagnosis of aortic stenosis.

Preoperative transthoracic echocardiography (TTE) reflected severe aortic stenosis (AS), mild aortic regurgitation (AR) with left ventricular (LV) ejection fraction of 60%. TTE also interpreted abnormalities consistent with the SV aneurysm. Cardiac angiography was also performed preoperatively, which revealed SV aneurysm affecting the left coronary cusp (LCC), no abscess cavity, fistula or dissection. Preoperative computer tomography (CT) scan of the chest concluded a 2 cm aneurysm adjacent to the inferior border of aortic valve (AV).

This gentleman was scheduled for elective aortic valve replacement (AVR) and repair of the aneurysm of SV with the possibility of interposition aortic graft or ascending aorta replacement with coronary implantation if the aneurysm appeared to involve the coronaries arteries.

A 2-dimensional (2D) transesophageal echocardiography (TEE) probe was inserted post anaesthetic induction and a comprehensive intraoperative TEE examination was performed. Our intraoperative TEE findings were different from the preoperative TTE and radiological work up. We acquired all the standard TEE views with special attention to the views that evaluate the AV, SV and ascending aorta. These are the mid esophageal short axis (ME SAX) and mid esophageal long axis (ME LAX) views focussing on the structures of interest for this surgery. All images and video loops were acquired with and without colour flow doppler (CFD) with an appropriate Nyquist limit. We found that the AV was bicuspid. There was severe AS with a peak gradient of 70 mmHg with a mean arterial pressure of 65 mmHg. There was a mild, central aortic regurgitant jet and there was no SV aneurysm. There was a cavity just above the non-coronary cusp (NCC)/left coronary cusp (LCC) commissure. CFD revealed that there was no communicating fistula among the cardiac chambers. Left and right ventricular systolic function appeared to be normal.

(Figures 1-5 shows the ME SAX, LAX and CFD views showing cavity and measurement).

ME AV SAX view showing the cavity above the LCC and NCC. Note the AV area by planimetry.

ME SAX = mid esophageal short axis; AV = aortic valve; LCC = left coronary cusp; NCC = non-coronary cusp.

ME AV SAX view with CFD showing the colour flow into the cavity.

ME SAX = mid esophageal short axis; AV = aortic valve; CFD = colour flow Doppler.

Showing the measurement of the cavity in the ME SAX view. ME SAX = mid esophageal short axis.

ME AV LAX view showing the cavity and measurement of the AV annulus. Note that Zoom function is enabled. ME LAX = mid esophageal long axis; AV = aortic valve.

ME AV LAX view showing the cavity measurement. Note that the Zoom function is enabled. ME LAX = mid esophageal long axis; AV = aortic valve.

The cavity measured 2.11 x 1.33 cm in size as shown in Figure 3. We disclosed our findings, showing the TEE video and still images to the operating surgeon before commencing surgery. Our clear communication made the surgeon aware of  the possibility of different surgical findings to that of the preoperative TTE and imaging diagnosis.

Actual surgical findings were confirmed by the surgeon with direct examination of the AV, SV and surrounding structures. These direct examination findings were exactly the same as interpreted by our intraoperative TEE examination. The surgeon found that the AV was bicuspid with fusion of the RCC and NCC. Immediately subvalvular to the NCC/LCC commissure was a blind ending cavity. This was not communicating with the left atrium (LA) and there were no other communicating fistulas. The surgeon also made a further comment that resembled an appearance of previous abscess cavity. There was no active endocarditis. This situation was suggestive of chronic cavity appearance with no active ongoing infection.

The operation performed was an AVR with bioprosthetic valve, the cavity was obliterated with deep pledgeted sutures and the residual cavity was filled up with bioglue. This obliteration of the cavity produced a fixed shelf bulging.

TEE at the time of weaning from CPB demonstrated well seated bio prosthetic AV. Furthermore, the valve appeared to have normal leaflet motion with no paravalvular regurgitation and adequate deairing. A bulge was visible indicating obliterated cavity. Weaning and separation from cardiopulmonary bypass (CPB) was smooth, easy and no difficulties were encountered. At the end of surgery, the patient was transferred to cardiac surgical intensive care and extubated in 2 hours’ time. He was transferred to high dependency unit (HDU) the next day and discharged to general ward 24 hours later.

During his stay in the ward, he had high temperature spikes and a blood profile showing rising C-reactive protein. Blood cultures that were sent during his temperature spike had isolated coagulase negative staphylocoocus hominis. The AV tissue sent to microbiology during surgery isolated two species of coagulase negative staphylococci: staphylococcus hominis and staphylococcus epidermidis. He was managed in the ward over the proceeding days, his temperature subsided and he made a good recovery. Subsequently, he was discharged from the hospital on the 9th postoperative day.

AV endocarditis is a serious infection as it destroys the native AV and its complications include severe AR, conduction disturbances and less commonly intracardiac fistula [1, 2]. The quoted incidence of endocarditis after prosthetic valve replacement is in between 2-4%. Complications include periannular abscesss in about 80% and intracardiac fistula formation in 14% of patients with AV endocarditis [3]. Though more common for prosthetic valve endocarditis, coagulase negative staphylococcus is responsible for 3-8% of endocarditis in native valves [4]. The Duke criteria merge echocardiographic, laboratory and clinical findings to establish the diagnosis of endocarditis [5, 6].

The usual familiar communications happen to be between aorta and right atrium (RA), right ventricle (RV) or left ventricle (LV) [7]. The region between mitral and aortic annulus is relatively avascular. This makes the spread of abscesses, aneurysm and fistula formation much easier [8]. These authors in a small case series, found 44% times the complication at this junction of the AV and mitral valve (MV) annulus. Of these 13% resulted in fistulae into LA and another 13% had resulted in perforation of the anterior mitral valve leaflet. Aorto-LA fistulas show a close association with bacterial endocarditis, abscess cavities, ruptured SV aneurysm, Bechet syndrome or aortic dissection [7, 9,10,11,12,13,14,15,16].

A differential diagnosis of SV aneurysm includes ASD, VSD, cardiomyopathy and coronary artery anomalies.

An interesting case report showed a periannular aortic valve abscess perforating the LA and had produced a systolic jet on the CFD which had been misinterpreted as mitral regurgitation (MR) on preoperative TTE. The intraoperative TEE interpretation correlated accurately with the surgical findings and resulted in a total change of surgical plan [17]. Dimitrious Patsouras and et al reported a case of aorto-LA fistula post AVR in a 70 year man who progressed to severe decompensated congestive cardiac failure at an excessive speed resulting in death. TTE helped here in making the preliminary diagnosis; but the definitive diagnosis was achieved with TEE using 2D and CFD modes. The authors recommend TEE as the procedure of choice for establishing the correct diagnosis in this situation and prompte emergency surgical intervention [18]. If the AV abscess involves left ventricular outflow tract (LVOT), this may lead to fistula of the RA [19]. Jen-Yu-Wang et all reported a preoperative 3D TEE demonstrating precise localisation of an aortocardiac fistula that penetrated the aortic annulus near the NCC. It also allowed a precise assessment of the extent of vegetation. The authors hence recommend 3D echocardiography as a vital diagnostic tool helping in planning surgical intervention [20].

The usual sequence of patient referral to the cardiac surgeon is by a cardiologist. If the TTE has been inconclusive, the cardiologist usually proceeds to perform TEE in an outpatient basis. However in this case, the cardiologists did not seem to feel the necessity to perform TEE preoperatively. They proceeded to perform angiography and CT of the chest. We feel that TEE should be performed preoperatively as a routine for the pathologies related to the SV or in any situations when TTE has been inconclusive. Cardiac MRI is another option to keep in mind for confirmation of the diagnosis.

In our case, the preoperative TTE appearance was deceptive and hence misleading to the diagnosis.

Echocardiography is a vital component for the assessment of cardiac structures in endocarditis.

It provides precise assessment of vegetation, valvular structures, cardiac function, AR and other complications [21]. TEE is superior to visualise the aorto-left atrial fistulas because of the close proximity of the TEE probe transducer to this area. Hence, imaging artefacts are diminished with TEE in comparison with TTE. [22] ME AV SAX and LAX are preferred views and colour mode is optimised by adjusting the Nyquist limits between 50-60 cm/s to achieve accuracy before making interpretations. Of similar crucial importance is to ensure that the colour box size and depth settings are at their smallest to improve temporal resolution and hence the image quality [23].

To conclude, we highlight the following take home messages:

- Preoperative imaging by TEE for pathology involving sinus of Valsalva.

- Cardiac MRI is possibly an important tool to confirm the diagnosis preoperatively.

- Preoperative history of fever, as in our case, should be considered as a vital piece of information. With this in mind, further investigations should be performed to establish or rule out the possibility of endocarditis.

- Intra-operative, three-dimensional echocardiography would help in confirming the diagnosis in an event of a dilemma. Of course, this requires adequate expertise and competence.

- In addition to the vigilance of the anaesthetic team, it is also of crucial importance to communicate effectively with the surgical team to ensure the surgeon approache it with an open mind and anticipates different findings from the preoperative work up.