DISCUSSION
The incidence of prosthetic graft infection after aortic replacement has
been reported to range from 0.5 to 9% and with mortality rate of
25-88%.3 In patients with graft infection and
mediastinitis, effective and urgent treatment is crucial to prevent
recurrence of infection and complications. The ideal treatment has not
been clearly defined so far. Most of the studies include retrospective
and relatively small patient cohort.
The most effective treatment of TAGI is the removal of the foreign
material.3,4 However, removal and replacement of
infected aortic grafts has high mortality and morbidity
risks.1,3,4 As a less invasive approach graft-sparing
strategies are advantageous for high-risk patients. Graft-sparing
strategies comprise debridement, irrigation, closed continuous
irrigation, VAC therapy and tissue flap coverage. Using VAC treatment
instead of closed continuous irrigation in mediastinitis treatment seems
to have better outcomes.5 The most preferred tissue
flap for TAGI is omentum.3,4 Pectoralis major, rectus
abdominis, latismus dorsi muscles has also been
used.1,4,5
Umminger et al2 compared 11 TAGI cases of graft
replacement and 14 TAGI cases of graft-sparing techniques. Their
graft-sparing technique included aggressive debridement, extensive
irrigation with a povidone–iodine solution and/or octenidine
dihydrochloride followed by continuous mediastinal irrigation with
antibiotic solutions in combination with systemic application of
antibiotics for 2 weeks without omental or muscle flap usage. Their
in-hospital mortality was 18% in the graft replacement group and 14%
in the graft preserved group which was not statistically significant.
They reported 14% (2 patients) reoperation rate after graft
preservation technique due to recurrent graft infection at a median
follow-up of 1.5 years who were eventually required graft replacement
and one of them died on early postoperative period.
In another recent study by Uchino et al6 17 patients
who underwent graft-sparing surgery for TAGI were analyzed. Hospital
mortality was 29.4% which was relatively high. Their graft-sparing
technique included local debridement of surrounding tissue with saline
irrigation and drainage. They performed omental transfer only if the
intraoperative gram stain was positive (in 5 patients). They did not
encounter recurrence of infection after discharge requiring
reintervention at a median follow-up of 18 months.
In the last two mentioned studies, they did not to use VAC therapy. Also
Umminger et al2 did not use omental coverage while
Uchino et al6 used in some patients. However, we
prefered to use both VAC and omental coverage in staged surgery. The
advantage of our approach was that we were able to achieve negative
mediastinal culture after VAC therapy prior to omental transposition and
sternal closure which enabled more secure environment to avoid future
recurrent infection.
Only a few cases have been reported in the literature that included a
combination of VAC and omental flap for TAGI
treatment.4,7,8 Saiki et. al. (8) treated 5 patients
with mediastinitis after aortic arch replacement using a combination of
VAC therapy and omental transfer. Four of the five patients survived to
discharge and have been reported to be free from mediastinal or graft
infection at a mean follow-up period of 36,2 months.
In conclusion, we have successfully treated aortic graft infection by
thoroughly debridement of all the infected tissues, followed by VAC
therapy, and finally covering the infected aortic graft and mediastinum
with omental flap. Combining VAC with omental transfer seems to be
effective in TAGI treatment and should be taken into consideration in
such cases.