DISCUSSION
Infections of the aortic grafts are rare postoperative complications of
aortic surgeries. They could happen in the early postoperative course
or, as in our case, later years after surgery. Although the incidence
varies between 1-5% based on center and surgeon expertise, the
condition can be challenging and associated with a high mortality rate[1, 2]. Due to its complexity and rarity, the
predisposing factors for aortic graft infection are yet to be
extensively identified by studies [3]. Although
the source of graft infection following the cardiac surgery procedure
remains unknown, skin flora is considered the most common source of
infection [3]. Early postoperative infections are
considered from direct skin flora contamination, whereas delayed
infection might be due to hemostatic agents, nosocomial septicemia, and
immunocompromised states [4]. In our case the most
likely predisposing factor for the patient was the immunocompromised
state secondary to the treatment of prostate cancer.
Symptoms of aortic graft infection are often vague, and this requires a
high degree of suspicion from the clinician when treating patients with
pre-existing aortic grafts. It could present as a myriad of vague
symptoms, including: fever, malaise, weight loss, back pain,
leukocytosis, or abdominal pain. Computerized tomography (CT) with
contrast enhancement is the diagnostic modality of choice in aortic
graft infections [5].
The EuroScore is a simple and quick way to assess patients’ risk of
mortality. Our patient had a score of 15%, which directly correlates to
a 15% chance of postoperative death. Our patient also had multiple risk
factors such as advanced age, urgent nature of procedure and history of
previous cardiac surgery and anemia. Although anemia is not part of the
EuroScore, studies have noted an increased mortality associated with
pre-operative anemia especially in the setting of open heart surgery[6]. Our patient was managed in a hybrid operating
room setting, where the patient first underwent drainage of their
peri-aortic abscesses in a surgery that carries a mortality risk ranging
between 19 to 25%. Subsequently, they underwent a TAVR.
Post-operatively, the patient was transferred to Cardiovascular ICU and
managed in the standard fashion.
The surgical management of acute graft infection depends on the degree
and extent of infection. The general belief is that if the graft and
autologous tissue were still surrounded by healthy tissue, the survival
rate was higher if the vascular prosthesis was not removed[3, 7]. In our case, the graft was not infected,
there were no signs of endocarditis and existing prosthetic grafts could
be salvaged, so only local debridement was performed followed by
placement of antibiotic beads around the graft site.
As previously mentioned, TAVR has become a game changer in the field of
aortic valve surgery and thanks to this approach we were able to
successfully treat a critically ill patient in a multi-disciplinary
setting.