DISCUSSION
Primary pericardial synovial sarcoma is an exceedingly uncommon, highly
aggressive neoplasm. Despite the striking predominance for males between
adolescence and early youth, we present a 63-year-old Caucasian female
with extensive tumor superior to the fibrous cardiac
skeleton.1,8
Due to its extreme rarity, most knowledge about this sarcoma, including
surgical management, is limited to case reports. Many surgical nuances
are omitted thereby leaving surgeons with little guidance for details
regarding operative resection and reconstruction. Incomplete resections
have previously been described due to tumor complexity and extent of
invasion.9,10 In particular, Yano et al. describe an
18-year-old male patient with a pericardial synovial sarcoma in nearly
the exact anatomical pattern as our patient’s presentation. However,
Yano et al. explain that complete tumor resection was not feasible at
the time due to the extent of invasion. One must wonder whether guidance
on the modified autotransplantation technique and subsequent adjuvant
treatments would have proved beneficial in preventing their patient’s
death from local recurrence.
The modified autotransplantation approach offers a great alternative to
the full autotransplantation technique described in cardiac cancer
literature.3 Full resection of the heart is not always
required and complicates reconstruction, with the potential to cause
problems, particularly if the surgeon is not familiar with cardiac
transplantation. Even with transplantation experience, complications
from IVC reconstruction are possible, especially from ostial coronary
sinus distortion or stenosis which can lead to
death.11 Not disrupting the IVC also eliminates the
risk of IVC stenosis and obstruction, which have been previously
described with the bicaval orthotopic heart transplant technique and
caused by edema at the suture lines, thrombus, and tight
anastomoses.12-14 At times, IVC stenosis and
obstruction may be less clinically obvious, with reports of diagnosis up
to two months postoperatively.12,15 However, there is
a risk of profound hemodynamic compromise, hepatic failure, or
multi-organ systemic failure if this rare but catastrophic complication
is not immediately corrected.13 Furthermore, time
saved on reconstruction will add to the overall benefit of the
operation. Modified autotransplantation allows for significant tumor
resection with less reconstruction, re-implantation, and ischemic time
on these very complex and lengthy procedures compared to a full explant.
It facilitates the principle of maximal tumor resection with minimal
surgical manipulation. It is for these reasons that full
autotransplantation is rarely undertaken.
There are many intricacies to the modified autotransplantation approach.
SVC cannulation for cardiopulmonary bypass should be undertaken
carefully and be placed as superior as possible to maintain enough cava
for re-anastomosis to the reconstructed heart. Moreover, incision into
the SVC should be oblique to decrease the likelihood of subsequent
stenosis. Transection of the superior great vessels leads to wonderful
exposure of the great vessels and base of the heart. It is the first
step in considering what else must be transected to allow for adequate
tumor extirpation without compromising usual cardiac attachments and
their potential detrimental consequences. Reconstruction of the origin
of the pulmonary veins may be fraught with danger; however, downstream
complications may be minimized if late pulmonary vein stenosis can be
avoided. One must realize that bovine pericardium is inelastic and may
be prone to stenosis either by scar or by undersizing neo-conduits or
openings into a flaccid and thus contracted pulmonary vein opening. This
complication must be anticipated at the initial reconstruction as it
often takes time to manifest. Furthermore, cardiac distortion occurs
with simultaneous right-left atrial reconstruction. Therefore distortion
related to mal-reattachment of the reconstructed heart to the body is
also a danger, particularly if usual landmarks for re-connection may be
missing or misunderstood. While none of these are insurmountable, any
reduction in potential complications related to re-attachment of the
resected and reconstructed heart is desirable.
It is noteworthy that loss of atrial contractility is often fairly well
tolerated even with complete atrial reconstruction.2Patients may regain cardiovascular function to a tolerable degree.
However, this has not been studied clearly. We have seen patients at our
institution demonstrating signs and symptoms of cardiac failure despite
reasonable ventricular function following complete atrial resection. It
is unclear whether this is a consequence of atrial noncompliance or a
lack of an atrial kick. We have seen evidence of otherwise unexplainable
pulmonary hypertension and peripheral edema in patients with variously
reconstructed atria, including partial reconstruction. For this reason,
atrial reconstruction should be performed while leaving large residual
atria. It is important to note that extensive ventricular tumor
involvement will limit the surgical resection and such patients may not
be the best candidates for an autotransplantation.2
Autotransplantation, either complete or modified, is highly dependent on
surgical experience and skillset. The adage “only remove as much
as YOU can reconstruct ” is key. Extensive experience in cardiac
transplantation and availability of skilled cardiothoracic surgeons are
necessary for safe execution. Notably, the only other case report of a
modified autotransplantation technique for a primary synovial sarcoma
was performed by the same surgeon and center as in this case
report.7