Operative findings
The right atrium, the ascending aorta, and the anterior portion of the
right ventricle were highly adherent and exfoliated. Cardiopulmonary
bypass was established with cannulation of superior and inferior vena
cava and ascending aorta. The cardioplegia selectively injected from the
LCA easily generated cardiac arrest, and thereafter, a retrograde
coronary perfusion was performed every 20 minutes. After coronary
peripheral anastomosis under circulatory arrest, upon observation of the
aortic root, it was noted that the previously replaced prosthetic valve
was partially dislocated at the non-coronary cusp annulus. During the
removal of the bioprosthetic valve, pannus was identified underneath the
valve, and extensive efforts were made to remove as much of the pannus
as possible. The abscess cavity was open, extending from the LCC just
below the LCA ostium and to the RCC in 12 o’clock direction, with the
non-coronary cusp (NCC) at the center (Fig. 2). When creating a carrel
patch for LCA, RCA was running within the aortic wall, and it was close
to the abscess cavity located at the dorsal RCC. To prevent potential
damage caused by detachment, the RCA was transected, and a bypass using
the great saphenous vein on RCA #2 was created to facilitate the
management of the LCA orifice. The LCC and RCC still had remaining
annulus, and an everted mattress technique was used to attach a suture
to the annulus. However, since there was no annulus left in the NCC, a
suture was placed from the outside of the aortic wall to secure it. We
selected a 21mm Freestyle valve. LCA was reconstructed by Carrelpatch
method. After releasing the aortic blockage, there were recurrent
episodes of ventricular fibrillation, indicating a potential perfusion
abnormality in the LCA. As a result, coronary artery bypass grafting was
added to the left anterior descending artery in the great saphenous
vein. Under the assistance of the intra aortic balloon pumping (IABP),
the cardiopulmonary bypass was safely discontinued, and the patient was
successfully transferred back to the Intensive Care Unit. The total
operating time was 565 minutes, with a cardiopulmonary bypass time of
366 minutes and aortic clamping time of 231 minutes. Due to the
patient’s stable hemodynamic status, the IABP was removed on the same
day of the surgery. Postoperative daptomycin 300mg/day for 4 weeks
resulted in improvement of the inflammatory response. No bacteria were
detected in the abscess tissue obtained during the surgery. A
postoperative CT scan confirmed the patency of the graft. On the 32nd
day after the surgery, the patient was transferred to the hospital
without any abnormalities in the Freestyle valve. There was no
recurrence of infection signs observed for two years.
DISCUSSIONSingle coronary artery disease is a rare congenital coronary artery
malformation, with an reported incidence of 0.04-0.06% based on
coronary angiography [1][2]. The Lipton classification is
commonly used for classifying this disease [3]. In our case, the RCA
forms a common opening in the LCC and courses within the anterior aspect
of the aortic wall before following a normal trajectory, which
corresponds to a classification of II-B in the Lipton classification
system. Patients with a single coronary artery disease are known to have
a high incidence of congenital heart disease including aortic bicuspid
valve, tetralogy of Fallot, macrovascular dislocation, etc, in 40% of
cases. 4) However, in the age of 76 in this case undergoing single
aortic valve replacement (AVR), the findings revealed that a tricuspid
aortic valve and no other anatomical abnormalities, except for the
presence of a common orifice where the RCA originated from the LCC. It
is important to note that even in cases without cardiac malformation,
ischemic heart disease, sudden death, heart failure, and conduction
disorders have been reported to occur in patients with single coronary
artery disease. The pathogenesis of ischemia in such cases may be
attributed to factors such as compression due to the artery running
between the aorta and the pulmonary artery, or the origin of the
coronary artery being at an acute angle, leading to conditions like
slit-like entrance stenosis caused by the artery running within the
aortic wall 5).
This case involves a single coronary artery disease classified as Lipton
L II-B, where the coronary artery runs with a risk of ischemia. However,
in this case, there was no evidence of myocardial ischemia during the
initial AVR surgery or in the preoperative assessment for the current
surgery. Due to the inability to evaluate the condition at that time,
bypass surgery was not initially considered. However, during the
creation of the carrel patch, we encountered significant adhesions
caused by the abscess at the annulus, making it difficult to separate
the RCA. In addition, the distal portion of RCA #1 was adhered to the
abscess cavity, raising concerns about potential coronary artery
stenosis due to the spread of inflammation. Therefore, RCA was bypassed
with the great saphenous vein. In addition, due to the suspected
abnormal perfusion of LCA reconstruction, indicated by the occurrence of
ventricular fibrillation during cardiopulmonary bypass, a bypass was
performed using the great saphenous vein to the left anterior descending
artery. This occurrence might have been attributed to the flexion of the
carrel patch caused by adhesion of the aortic root. In cases where
severe adhesion is suspected in reoperation for single coronary artery
disease, it might be more beneficial to consider performing a Pielher
reconstruction to prevent the occurrence of such adverse events. In this
rare case, the choice of bypass graft is crucial. The RCA has the
potential to cause ischemia due to its compression between the aorta and
the pulmonary artery. Unlike stenosis caused by arteriosclerosis, this
type of narrowing usually allows for maintained blood flow in the
coronary artery. When considering the internal thoracic artery as a
graft option, there is a risk of flow competition and the need for
additional revascularization (6). Therefore, we decided to use the great
saphenous vein as the bypass graft instead. However, even in bypass
procedures using the great saphenous vein, several cases of occlusion
have been reported, and there are also reports highlighting the
advantages of the unroofing method (7). In this particular case, CT and
myocardial scintigraphy were performed 2 years after the surgery to
confirm graft patency and rule out ischemia. However, strict follow-up
will be necessary in the future.