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