MANUSCRIPT
INTRODUCTION
Transcatheter aortic valve implantation (TAVI) is the preferred
procedure among severe aortic stenosis patients with high surgical risk
and comorbidities. While the elderly population grows in number,
popularity of TAVI and demand for it rises. Consequently, probability of
complications caused by TAVI increases. When compared to other TAVI
related complications infective endocarditis is rarely seen with
incidence of 0,2%-3,1% at 1 year post implantation (1) With the
increase of TAVI indications, post TAVI infective endocarditis (TAVI-IE)
is a subject that should be experienced. However, TAVI-IE requires
expertise in diagnosis and treatment. In this report, we present a
75-year-old TAVI patient with postprocedural infective endocarditis.
CASE PRESENTATION
A 75-year-old patient with history of coronary artery bypass grafting
(CABG) underwent TAVI. On the post-op 2nd day, a high fever was noticed
and after two sets of blood cultures were taken, intravenous antibiotic
therapy was started. Transthoracic echocardiography (TTE) showed no
vegetation or mass formation, so transoesophageal echocardiography (TOE)
was planned. TOE images also showed no vegetation, paravalvular leakage
(PVL) or perivalvular complication however a periaortic soft tissue
thickening was observed (Video 1,2) In order to diagnose peri-graft
infection a computed tomography (CT) scan was performed. Thickening of
right coronary cusp of prosthetic aortic valve raised suspicion for
vegetation formation. While the patient was taking appropriate
antibiotic therapy, routine TTE controls indicated periaortic soft
tissue thickening but no vegetations could be seen. After two weeks of
appropriate antibiotic therapy, control CT scan displayed small
milimetric vegetations on TAVI stent struts (Figure 1A, 1B). While the
patient was under treatment, his blood work showed a regression of
infection markers and he was asymptomatic, therefore it was decided to
continue to follow the patient with the conservative approach by the
Infective Endocarditis Team. A week after the second CT scan high fever
was detected again and in order to diagnose new complications resulting
from infective endocarditis a control TOE was planned. TOE images (video
3,4) showed pseudoaneurysm at periaortic site therefore a surgical
approach was obligatory for the patient rather than a conservative one.
After the preop preparations re-do aortic valve replacement was done
successfully. There were no complications after the surgery and control
imaging proved a normo-functioning bioprosthetic aortic valve.
DISCUSSION
According to American Heart Association (AHA) 2020 guideline
transfemoral TAVI is recommended for the patients who are 80 years of
age or older or younger patients whose life expectancy is less than 10
years and patients of any age whose surgical risk is high and whose
post-TAVI life expectancy is more than 12 months (2) Even though TAVI is
considered to be the less invasive approach compared to surgical aortic
valve replacement (SAVR), it still has a considerable amount of
complications that may affect the outcome. These complications include
stroke, life threatening bleeding, coronary artery obstruction, aortic
root rupture, acute kidney injury, moderate or severe prosthetic valve
regurgitation, prosthetic valve endocarditis or prosthetic valve
thrombosis (3) In this case we presented an early prosthetic valve
endocarditis (PVE) as a complication of TAVI, its diagnosis and our
clinical approach.
A systematic review from Khan et al. (4) showed that the mean incidence
of post-TAVI IE is 3,25%. and showed a high mortality rate with the
mean incidence of in-hospital mortality as 29.5%. Post TAVI-IE
incidence was detected to be similar to post SAVR-IE in many recent
trials (5). However, Post TAVI IE-associated mortality is significantly
higher compared to IE after native or prosthetic valve surgery (6). The
elderly patient population with high comorbidities seems reasonable to
explain why the post TAVI-IE mortality was the highest. Renal
impairment, moderate to severe PVL, orotracheal intubation,
self-expandable valve system, malposed valve, excessive manipulation,
and transapical approach have been reported as predictors of TAVI-IE in
various studies (5, 7).
For diagnosis European Society of Cardiology (ESC) suggests a combined
approach to PVE using multiple imaging modalities such as TTE, TEE,
computed tomography (CT), positron emission tomography (PET) or
single-photon emission computed tomography (SPECT) (8) As we implemented
with this case of post – TAVI IE, CT is essential while diagnosing
perivalvular complications and can give a more detailed and accurate
anatomical information compared to TTE or TOE in PVE. (9) Excessive
metal component of TAVI valve and presence of remnant calcified aortic
valve cause difficulties in echocardiographic evaluation (7). Therefore,
repeated echocardiographic evaluations and / or combined with other
imaging modalities in diagnosis of PVE is of the utmost importance in
this patient group.
For now, there is no special guidelines or recommendations for the
management of TAVI IE. Parenteral antibiotic therapy is still deemed to
be the first step of the management of TAVI IE (10). The group of
patients who undergo TAVI procedure have a higher risk profile and more
comorbidities compared to other groups with native valve endocarditis or
post-SAVR endocarditis. For this reason, overall data shows that TAVI IE
patients are less frequently operated on when compared to the other IE
patients (1) Anatomical complications caused by peri-annular extension
of the infective process such as involvement of mitral valve and
perforation of anterior mitral valve leaflet or development of
periaortic pseudoaneurysm (10) require immediate surgical intervention.
In the absence of these mechanical complications, decompensated heart
failure, uncontrolled infection or peripheric embolism, it is found to
be reasonable to keep a conservative approach with parenteral antibiotic
therapy (1) The infective endocarditis team has an extremely important
function in TAVI -IE with individualized treatment management choices.
We initially chose to continue with the conservative path in our patient
for several reasons: 1- The general condition of the patient was stable
and fever control was achieved with antibiotic treatment 2- Infectious
laboratory values decreased significantly at the beginning of the
therapy 3- No paravalvular complications were seen at the first imaging
(echocardiography/CT) evaluations. With different advantages for each,
multiple imaging modalities should be used for follow-up. The crucial
point in the management of this patient was the detection of a silent
pseudoaneurysm before the patient’s clinical deterioration. From this
point on, we believe that timing of surgery without clinical and
laboratory deterioration is the most important step in patient survival.
In order to decide on conservative or invasive approach for patients
with TAVI-IE, a close follow-up of symptoms and clinical status with the
help of different and repeated imaging modalities is required.
CONCLUSION
TAVI IE is a rare post-procedural complication, however it is possible
to see a rise of the number of TAVI IE as TAVI becomes a more common
procedure among elderly and even younger populations whose longer life
expectancy may result in long term complications including IE. There are
no specific guidelines for TAVI IE but recommendations from systematic
reviews. There is need for more research to determine whether surgical
or conservative approach is beneficial for these patients. As this
population of patients are fragile and have high surgical risk profile,
determination of which conservative or surgical method is the most
appropriate with close follow-up and repeated imaging methods seems more
sensible.