Case Summary
We report a 64yo male with a history of severe aortic stenosis who
underwent aortic valve replacement in 2015 with a 21 mm Mitroflow
bioprosthetic valve (Sorin, Arvada, CO) at an outside hospital. The
postoperative course was complicated by pan-sensitive Serratia
Marcescens deep sternal wound infection and mediastinitis requiring
multiple debridements and treatment with a six-week course of
intravenous vancomycin and ceftriaxone. He subsequently required a
sternal reconstruction using bilateral pectoralis major flaps and a
right rectus abdominis flap. He acutely did well from this
hospitalization. However, he then presented three months after his index
surgery with 2-3 day history of fevers, chills, and a new sternal mass.
His surgeon considered acutely decompressing the mass at the bedside but
decided to transfer the patient to our institution.
Upon arrival at our institution he was neurologically intact with an EKG
showing sinus tachycardia, all other vitals within normal limits. His
exam was impressive with a rapidly enlarging, erythematous, anterior
chest wall mass (Figure 1, 2 ). An urgent computed tomographic
angiogram (CTA) scan of the chest demonstrated a blush at the aortic
cannulation site with active arterial extravasation into a massive
pseudoaneurysm of the distal ascending aorta filling the entire anterior
mediastinum (Figure 3 ). Echocardiogram demonstrated grossly
normal left ventricle (LV) systolic function with poor visualization of
the ascending aorta. Percutaneous coverage of the pseudoaneurysm as a
temporizing measure was considered but not feasible due to a lack of
distal landing zone or a small enough neck.
Given the rapid expansion, he was taken emergently to the operating room
for repair. The right femoral vein and artery were cannulated and
patient was cooled. Due to several small aortic paravalular leaks and
concern for LV distension, a left anterior thoracotomy was performed and
an LV vent placed directly through the LV apex. Manual compression was
also required to keep the LV from distending.
By the time the patient’s temperature reached 28ºC with the LV
continuing to distend, a redo sternotomy was performed. Upon entering
the anterior mediastinum, the large pseudoaneurysm was grossly entered
with evidence if acute arterial hemorrhage. Circulatory arrest was
initiated and the aorta was rapidly dissected out to identify the aortic
cannulation site where multiple, pledgeted sutures were identified
loosely attached at the original cannulation site. A cowhorn dilator was
placed in the defect to control the aorta and cardiopulmonary bypass
(CPB) was re-initiated.
Now with some control of the aorta, a sternal retractor was placed and
the aorta was dissected circumferentially. Under a second duration of
hypothermic circulatory arrest. A large, bovine pericardial patch was
then sewn in running fashion around the defect. This appeared to achieve
hemostasis at the defect site and the patient was rewarmed and weaned
off of CPB without difficulty. The right groin and left anterior
thoracotomy were closed in standard fashion.
The decision was made to pack the chest due to mild coagulopathy and
prior complex closure. The patient remained intubated, sedated, and on
vasopressors for the duration of the postoperative period. Total time on
cardiopulmonary bypass was 171 minutes, with 24 minutes (6 minutes on
entry, and 18 minutes while sewing patch) of total hypothermic
circulatory arrest time.
His postoperative course was complicated by seizures thought to be due
to air embolism on subsequent MRI. His operative wound cultures grewCandida albicans . Although he underwent successful washout and
closure of his flaps, he later become profoundly hypotensive with acute
hemorrhage from his chest tubes. Upon emergently opening his chest, 3
liters of blood was noted in his mediastinum with bleeding from the left
side of the bovine pericardial patch. The aorta quality was poor.
Hemostasis was achieved with primary repair. Temporary closure was
performed and the chest was packed. The patient was weaned off pressors.
Ultimately, given the complex disease and concerning neurological
status, the decision was made to transition to comfort care and the
patient expired soon after.