Contrary to previous understanding, the most common benign primary cardiac tumor is now believed to be the papillary fibroelastoma (PFE), not the myxoma. These tumors are found 90% of the time on cardiac valves, with a particular preference for the aortic valve, though they can appear on any endocardial surface. With an average size of approximately 20 mm, they have a stalk-like shape and were historically termed “giant Lambl’s excrescences.” Most patients are asymptomatic, and the diagnosis is often incidental. Symptoms, when present, are typically secondary to tumor embolisms, whether cerebral, cardiac, or pulmonary. Symptomatic patients are clearly indicated for surgical excision. However, the management of asymptomatic patients remains controversial. 

This study aims to analyze Mayo Clinic’s experience with the surgical treatment of PFE and long-term outcomes. To this end, data from 1998 to 2020 was retrospectively reviewed, including any patient who underwent PFE surgery. The cohort was divided into primary PFE, where tumor excision was the surgical indication, and secondary PFE, where it was removed incidentally during another surgery. 

Of the 294 patients analyzed, 60% were female, and the mean age of the entire cohort was 66 years. Half of the cases were primary PFE, and of these 136 patients, half presented with symptoms of cerebral embolism or transient ischemic attack before surgery. In secondary PFEs, over a third of cases had preoperative tumor identification. The tumor was located mainly on the aortic valve, with right-sided location being rare. When the PFE was on a normal valve, 96% of cases allowed for shaving the valve without functional impairment. In-hospital mortality was low, at 0% for primary cases and 2.5% for secondary cases, attributed to patient comorbidities rather than the tumor. The rate of immediate postoperative neurological events was 1.3%. With a median follow-up of 8.5 years, the 10-year recurrence rate was 16%, with most cases managed conservatively. However, three patients underwent reoperation for tumor recurrence in the same initial location. Ten-year survival was 78% for primary cases and 54% for secondary cases (p = .003). 

The authors concluded that PFE excision can be performed safely, preserving the native valve and with a low risk of immediate postoperative neurological events. Long-term surgical outcomes are excellent, although recurrences are more frequent than previously thought. 

COMMENTARY: 

PFE was first described in the late 19th and early 20th centuries and has been known by various terms: papillary myxomas, papillary excrescences, and, as mentioned earlier, giant Lambl’s excrescences. There is even controversy as to whether PFEs are indeed Lambl’s excrescences. Lambl’s excrescences are thought to be reactive mechanical processes associated with normal valve function, typically located along the coaptation line. However, the etiology of both remains unknown, with minimal histological differences. Characteristics such as size, structural complexity, or location have been proposed to differentiate them, but these are arbitrary and artificial criteria. Some believe PFEs result from uncontrolled growth of Lambl’s excrescences. 

What is undisputed is their high embolic risk, which justifies primary PFE surgery. Surgery is known to halve cerebrovascular events at five years compared to non-operated patients, which translates into increased long-term survival. With routine use of transthoracic and transesophageal echocardiography, PFE incidence has risen, making it now considered more common than myxoma. Echocardiographic studies have shown that PFEs grow by approximately 0.5 mm annually and, depending on their location, may present symptoms sooner or later. Right-sided tumors, for instance, tend to have a more indolent course, with symptoms appearing when tumors are large. It’s essential to remember that less than 10% of PFEs may have multiple locations, so all suspected cases should include a thorough examination of all locations to avoid missing any. 

The most significant finding of this study is the 16% recurrence rate at 10 years, much higher than the previously assumed 3%. This raises several questions: how frequently should these operated patients be followed up? What imaging modality should be used? Should a more aggressive approach be taken rather than merely shaving the valve? Regarding the latter, adding cryoablation to the resection bed could provide benefits, as it has shown not to damage the valve, although no solid data on long-term recurrence prevention exists. Some groups, however, perform this systematically. 

To understand this article’s findings in context, it’s crucial to consider its limitations. This is a single-center retrospective study from a quaternary hospital, which may not reflect the caseload of a standard hospital. Data were not analyzed for patients with a PFE diagnosis who were not operated on. Long-term neurological event data and echocardiographic data were unavailable for nearly half of the cohort, so the recurrence rate could be underestimated (in addition to the consequences of the conservative approach taken in most cases). 

In conclusion, despite these limitations, this study is one of the largest published on PFE and significantly contributes to potentially changing the surgical management of this rare pathology. 

REFERENCE:

Mazur P, Kurmann R, Klarich KW, Dearani JA, Arghami A, Daly RC, et al. Operative management of cardiac papillary fibroelastomas. J Thorac Cardiovasc Surg. 2024 Mar;167(3):1088-1097.e2. doi: 10.1016/j.jtcvs.2022.06.022.