Background
The aim of this study was to characterize papillary fibroelastomas (PFEs) and their clinical sequelae in patients with hypertrophic cardiomyopathy (HCM). PFE is the third most common primary cardiac tumor and can be associated with neurologic events. Because endocardial trauma has been implicated in its pathogenesis, the occurrence and outcomes of PFEs in patients with HCM were retrospectively analyzed in this study.
Methods
Echocardiograms and medical records were reviewed for characteristics of PFEs in 19 patients with HCM who underwent septal myectomy.
Results
PFEs were detected preoperatively by transthoracic echocardiography in 5 patients, by transesophageal echocardiography in 2 patients, and perioperatively in 12 others. Three patients had previously undergone septal myectomy. Although the majority of patients (n = 11 [58%]) had 1 PFE, the number ranged from 1 to >40 (median, 1.0). PFEs arose on the aortic valve (47%), in the left ventricular outflow tract (42%), and in the right heart (11%).
Conclusions
In this study of patients with HCM, 89% of PFEs were located on the aortic valve or in the left ventricular outflow tract compared with about 40% to 50% in prior studies of PFEs in general. This suggests that endocardial trauma due to turbulent left ventricular outflow tract flow may predispose to PFE development. Because of the high incidence of neurologic events among patients with HCM, PFEs may not be innocuous and should be searched for in patients with HCM and unexplained neurologic events.
Papillary fibroelastoma (PFE) is the third most common primary cardiac tumor, with an echocardiographic prevalence at the Mayo Clinic of 0.02%. PFEs are generally small (<1 cm) and pedunculated, with numerous fronds forming a headlike mass, emanating from a stalk (Figure 1) . Microscopically, each frond is characterized by a core of elastin and collagen coated by a myxoid layer and covered by a single endothelial layer. Although the majority of PFEs are clinically silent, they can produce life-threatening complications, such as embolism, stroke, or sudden death. Embolic material may be thrombotic or may consist of PFE fronds.
The pathogenesis of PFEs remains controversial. They have been considered benign neoplasms, organized thrombi, hamartomas, and unusual responses to infection or endocardial injury. Repetitive hemodynamic trauma has been postulated to play a role in their development, and they have been associated with previous intracardiac procedures and mediastinal irradiation.
Hypertrophic cardiomyopathy (HCM) is an inheritable cardiac disorder with a broad clinical spectrum. Dynamic left ventricular outflow tract (LVOT) obstruction is common in HCM, occurring in more than two thirds of these patients. Dynamic LVOT obstruction results in considerable hemodynamic shear stress and turbulence along the LVOT and on the aortic valve cusps. Because of this shear stress, patients with obstructive HCM may be particularly susceptible to the development of PFEs.
Accordingly, we undertook this retrospective study to characterize PFEs in this patient population. The aims of this study were to determine if there is a predilection for sites of hemodynamic trauma and to examine the clinical outcomes of these patients.
Methods
Patient Population
The study was approved by the Mayo Foundation Institutional Review Board. All patients had consented to the use of their medical records for research. We searched the HCM, echocardiography, and pathology databases to identify 2479 patients with HCM seen between January 1, 1990, and December 31, 2006, of whom 19 unique patients were diagnosed with pathologically proven PFEs. One of these patients has been previously reported. These PFE cases represented 14.7% of all pathologically proven PFE cases (n = 129) seen at the Mayo Clinic during the same time period. The diagnosis of HCM was defined by a hypertrophied, nondilated left ventricle in the absence of another systemic or cardiac disease that is capable of producing that magnitude of wall thickening. PFEs were defined histopathologically and echocardiographically by the features described earlier.
Clinical Features
Clinical information was obtained from the patients’ medical records, which included details about history, clinical events, echocardiography, cardiac procedures, and pathology reports. Three patients had previously undergone septal myectomy and had recurrent PFEs, which were included in the analysis.
Echocardiographic Features
Echocardiograms were then reviewed by two of the authors (G.K., K.W.K.). In each patient, the diagnosis of HCM was based on the identification of a hypertrophied and nondilated left ventricle (wall thickness ≥ 15 mm in adults). Significant dynamic LVOT obstruction was defined by a gradient ≥ 30 mm Hg at rest or ≥ 50 mm Hg with provocation (Valsalva maneuver or amyl nitrate).
Statistical Analysis
Data are presented as mean ± SD or as median (interquartile range [IQR]) as appropriate.
Results
Of 2479 patients with HCM seen between January 1, 1990, and December 31, 2006, 19 unique patients were diagnosed with pathologically proven PFEs. Five of these patients were identified by preoperative or outpatient transthoracic echocardiography (TTE) and 2 by preoperative transesophageal echocardiography (TEE) (0.28%).
Baseline Characteristics
Table 1 lists the baseline characteristics of the 19 unique patients with HCM and PFEs. The mean age at diagnosis of PFE was 49.0 ± 17.8 years, and 13 (68%) were women. At that time, patients had already been diagnosed with HCM for 9.7 ± 8.3 years. Sixteen of the 19 patients (84%) had resting LVOT gradients ≥ 30 mm Hg. Two patients who underwent previous septal myectomy did not have any evidence of residual LVOT obstruction, and 1 patient with HCM had no evidence of LVOT obstruction but had severe mitral regurgitation due to a flail posterior leaflet requiring mitral valve repair and septal myectomy for a thickened basal septum measuring 22 mm. Pertinent clinical characteristics are summarized in Table 1 .
| Variable | Value |
|---|---|
| Demographics | |
| Age (y) | 49.0 ± 17.8 |
| Women | 13 (68%) |
| Symptoms at time of surgery | |
| Syncope | 3 (15.8%) |
| Angina | 2 (10.5%) |
| Palpitations | 3 (15.8%) |
| Moderate to severe dyspnea | 15 (78.9%) |
| Medical/surgical history | |
| Coronary artery disease | 6 (31.6%) |
| Atrial fibrillation | 7 (36.8%) |
| Hypertension | 5 (26.3%) |
| Diabetes mellitus | 2 (10.5%) |
| Peripheral vascular disease | 0 (0%) |
| Cardiac arrest | 2 (10.5%) |
| Cardiac surgery | 5 (26.3%) |
| Septal myectomy | 3 (15.8%) |
| Family history | |
| HCM | 5 (26.3%) |
| Sudden cardiac death | 3 (15.8%) |
| Devices | |
| Implantable cardioverter-defibrillator | 2 (10.5%) |
| Permanent pacemaker | 5 (26.3%) |
| Current surgery | |
| Septal myectomy | 19 (100%) |
| Aortic valve replacement | 2 (10.5%) |
| Mitral valve replacement | 2 (10.5%) |
| Mitral valve repair | 1 (5.3%) |
| Pulmonary valve surgery | 1 (5.3%) |
| Coronary artery bypass grafting | 1 (5.3%) |
PFE Characteristics
In 5 patients (26%), PFEs were diagnosed preoperatively by TTE. In 1 of these 5 patients, TTE was performed to assess for an embolic source following a neurologic event. The other 4 were discovered incidentally as part of workup for HCM. In 2 patients, the PFEs were seen on TEE but not TTE. In the remaining 12 patients, PFEs were identified only at the time of operation by the surgeon and/or pathologist. We reviewed these images and were also unable to identify the PFEs retrospectively.
In 17 of 19 patients, the actual sizes of the largest PFEs were available. The other 2 were described as “small” and “microscopic.” The median largest dimension of the 7 PFEs detected by TTE or TEE was 1.4 cm (IQR, 1.2-1.8 cm). In contrast, the median largest dimension of the 12 PFEs detected only by the surgeon or pathologist was 0.95 cm (IQR, 0.5-1.1 cm). Among 17 PFEs located on the interventricular septum, LVOT, or aortic valve, only 3 (17.6%) were diagnosed by TTE only, and with the addition of TEE, another 2 (11.8%) were diagnosed.
Eleven subjects (58%) had only 1 PFE. However, 1 patient with previous septal myectomy had >40 PFEs along her LVOT. One patient had 4 PFEs, 4 patients had 3 PFEs, and 2 patients had 2 PFEs.
Most PFEs arose on the aortic valve (47%) or along the LVOT (42%) (Figure 2) . One patient with a right ventricular outflow tract gradient had a PFE just distal to the pulmonary valve (Figure 3) , and another patient developed a PFE on the tricuspid valve. Three patients had previously undergone septal myectomy, and PFEs subsequently originated near the previous resection site in all 3 (Figure 4 and Video 1; view video clip online; of note, these 3 patients also reportedly had PFEs at the time of original myectomy, noted by operative notes and pathology from the outside institutions. In these 3 patients with recurrent PFEs, 1 had no residual gradient, another had a minimal residual gradient (12 mm Hg at rest), and the third had a significant resting gradient (71 mm Hg at rest). Pertinent echocardiographic characteristics are summarized in Table 2 .
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