Anti-inflammatory properties of amniotic membrane patch following pericardiectomy for constrictive pericarditis

A 34-year-old male had a history of orthotopic heart transplant for hypertrophic obstructive cardiomyopathy and subsequent tricuspid repair for severe tricuspid regurgitation due to prolapse. The heart transplant was performed at a medical center in a neighboring state, with both prior surgeries performed by two different surgeons. He was doing well for over 3 years following these procedures, maintained with immunotherapy consisting of 2.5 mg Prograf® BID and 250 mg CellCept® daily as noted by the CT 7 Transplant Database. He then developed a one-week history of marked fatigue, worsening shortness of breath, and sinus tachycardia on electrocardiogram and was transferred to our facility from a neighboring state. Upon arrival, the patient’s ejection fraction was significantly reduced at less than 20%, compared to his usual baseline of 60% last recorded 1.5 years prior to this presentation. Given the concern for acute transplant rejection, the patient underwent endomyocardial biopsy via catheterization, which revealed evidence of Grade 1R mild acute cellular rejection without the presence of antibody-mediated rejection as evidenced by a pathologic antibody-mediated rejection (pAMR) of 0. Hemodynamic findings from right and left cardiac catheterization revealed equalization of diastolic filling pressures with discordance after volume loading, consistent with constrictive physiology. Additionally, Freidreich’s sign was present with both steep x and y descent of the jugular venous pressure (JVP) tracing with increased left and right ventricular diastolic pressures with dip and plateau (square root sign). The patient then underwent a cardiac magnetic resonance imaging (MRI) study to further evaluate the constrictive physiology. Cardiac MRI revealed mild pericardial thickening, mild flattening and bounce of the interventricular septum, intermediate epicardial signal on pre-contrast T2-weighted images and demonstrated intermediate delayed enhancement with post-contrast T1-weighted images consistent with fibrotic tissue (Fig. 1a, b). There was also moderate to moderate-severe tricuspid regurgitation. Given the hemodynamic values from cardiac catheterization and pericardial thickening, surgery was recommended to replace the tricuspid valve and remove the fibrotic epicardial material.

Using a redo sternotomy approach, complete phrenic to phrenic pericardiectomy, removal of Gore-Tex membrane from previous surgery and a tricuspid valve replacement were completed. Gross intraoperative findings of the pericardial space included thick, gelatinous material on the anterior surface of the heart, and the pericardium and Gore-Tex membrane were fused to the thickened pericardium on the anterior surface of the heart. (Fig. 2a) Prior to closure, four human allograft membranes were topically placed over the right atrium, right ventricle and left ventricle (Fig. 2b) for their anti-fibrotic and anti-inflammatory properties [7, 8]. The surgical pathology report later confirmed fibrosis of the explanted tricuspid valve, pericardial fibrosis, and chronic pericardial inflammation. Though constrictive physiology was still noted, post-contrast T1-weighted cardiac MRI images demonstrate significant improvement (Fig. 1c, d). Furthermore, a five-week postoperative fat-suppressed T2-weighted MRI revealed no appreciable postoperative inflammation and an absence of pericardial effusion (Fig. 3).