Maleszewski, Joseph J.

Abstract Background New postoperative atrial fibrillation (POAF) occurs in about 40% after cardiac surgery. Mineralocorticoid receptor antagonists (MRA) are known to reduce chronic atrial fibrillation (AF) development and burden. We examined the impact of preoperative MRA use on POAF and also examine the atrial cell type impacted by MRA treatment during cold cardiac preservation. Methods Retrospective study of 19,042 patients who underwent cardiac surgery at Mayo Clinic in Minnesota, and performed 1:3 propensity matching to obtain 298 patients on preoperative MRA matched to 894 who were not. We also separately matched patients using preoperative diuretics. Single-nuclei RNA sequencing (snRNA-seq) examined MRA’s effects on different atrial cell types in canrenone (water soluble MRA) treated human donor hearts undergoing cold preservation followed by ex-vivo reperfusion and compared gene expression to the atria of patients with AF. Results Propensity matched preoperative MRA group had less new onset POAF (19.8% vs 31.5%, P<0.001). To account for the possibility that preoperative diuretic use and volume reduction may impact POAF, we propensity matched 298 preop diuretic users that included MRA use to another 894 patients who used a non-MRA diuretic preoperatively. Those who used preoperative MRA similarly had a lower incidence of POAF (19.8% vs 33.2%, P<0.001). No survival difference was present between the propensity matched groups that used preoperative diuretics (P=0.079). Preoperative MRA use also reduced the development of paroxysmal and chronic AF at 6 years of follow up. From our snRNA-seq data, we identified a subpopulation of atrial cardiomyocytes (CM2) that had high MR expression where canrenone suppressed the increase in MR target gene expression associated with cold preservation-reperfusion. These MR targets were conversely elevated in patients with chronic AF. Canrenone also suppressed other cardiac preservation associated genes that show elevated expression in atrial macrophages and pericytes from chronic AF atria. Conclusions Our studies show that preoperative MRA use is associated with 40% reduction in POAF as well as lowering long standing AF development by about 41%. Our cold cadiac preservation-reperfusion model showed that canrenone reduced expression of MR target genes associated with chronic AF, particular in cardiomyocytes with important roles in electrical conduction. Clinical Perspective What is New? This study shows that preoperative use of mineralocorticoid receptors antagonists (MRA) is associated with a reduced incidence of new onset perioperative atrial fibrillation after cardiac surgery utilizing cardiopulmonary bypass. We show that preoperative MRA use is associated with a lower incidence of developing more chronic paroxymal or sustained atrial fibrillation. Addition of canrenone, a clinically utilized water soluble MRA, to cardioplegia solution used during cardiac preservation can attenuate atrial inflammatory reponses and reduce signaling through molecular pathways that promote atrial fibrillation. What are the clinical implications? Perioperative use of MRAs may be considered to reduce early postoperative atrial fibrillation as well as lowering the risk of developing more chronic atrial arrhythmias. These findings support pursuing a clinical trial to determine the impact of MRA use on atrial arrhythmias following cardiac surgery in the setting of cardiopulmonary bypass with cold cardiac preservation.

Context.— Cardiac and pulmonary allograft recipients represent a unique population, frequently interacting with support groups and exhibiting intense curiosity about their pathology. Like other solid organ transplant patients, they have enduring and frequent interaction with the laboratory for routine allograft surveillance. Objective.— To address patient requests to understand what happens to their explanted organ and to better understand their disease while simultaneously improving awareness of pathologists’ roles in their continuing care. Design.— At routine follow-up appointments, transplant nurse coordinators offer each allograft recipient the opportunity to interact with a pathologist in our “ On My Path ” program. Organ viewing occurs in a private setting, in a specialized room. Relevant pathology is discussed, and questions are answered, with documentation in the medical record. The patient is subsequently gifted a 3-dimensional model of their explanted organ. Transplant coordinators were surveyed for their feedback on the experience. Results.— One hundred fifty-eight interactions have been documented (2017–2022) at our institution, including patients who underwent cardiac transplant (96, 61%), single or bilateral lung transplant (54, 34%), or combination lung and heart transplant (8, 5%). Transplant coordinators reported an increase in patient understanding of their disease and emotional closure related to the disease through the On My Path program. Conclusions.— Pathologists providing direct patient care is a feasible model that addresses currently unmet desires of the transplant population to better understand their pathology. Providing a 3-dimensional model helps to empower patients and drives satisfaction. These interactions also improve awareness about pathology as a discipline and its importance in the continued care of transplant recipients.

Solitary myofibromas are rare, benign, mesenchymal tumors typically found in the head and neck regions. We report an exceptionally rare case of a solitary cardiac myofibroma and its short-term management and outcome. A two-month-old infant was referred due to a murmur. Echocardiography revealed a 2 × 1 cm solitary mass originating from a mitral papillary muscle, causing severe regurgitation. Magnetic resonance imaging showed the mass to be homogeneous on T1, hyperintense on T2, and hypointense on first-pass perfusion imaging with no enhancement on delayed postcontrast imaging. The mass was surgically excised partially due to its involvement with the mitral valve. Postoperative recovery was uneventful, with echocardiography four months later showing no tumor recurrence and trivial mitral regurgitation. This report provides valuable imaging and pathology examples to aid in the recognition of this rare tumor and demonstrates that successful surgical excision is possible, even with significant cardiac involvement.

Abstract Background Non-bacterial thrombotic endocarditis (NBTE) is a non-infectious condition characterized by thrombotic and/or inflammatory depositions involving the cardiac valves. It is a challenging diagnosis of exclusion. Purpose This study aimed to better characterize patients with pathologically proven NBTE and assess its clinical, echocardiographic characteristics and prognostic implications. Methods We retrospectively identified patients with pathology-proven NBTE at a single center. Patients with positive preoperative blood cultures, a history of active or treated infective endocarditis, or identification of valvular organisms by special stains were excluded from the study. Patients with pathology reports of valve perforation or chordal rupture were also excluded because of the high likelihood of an infectious etiology for these lesions. Results A total of 53 patients with NBTE (median age 57 years; 61% females) were identified. In this cohort, 22% had a history of malignancy, 30% had connective tissue disease, 32% had coronary artery disease, and 11% prior history of NBTE. Neurological events accounted for 18 (34%) of the presenting symptoms (TIA n=17, CVA n=9), while new valvular dysfunction in 7 (13%) and fever in 8 (15%) of patients. Five patients (9%) had NBTE involving more than one valve. NBTE involved the mitral valve in 64%, aortic valve in 38% prosthetic/mechanical valve in 11%, and tricuspid valve in 5%. NBTE was identified at the time of autopsy in 34% of patients. NBTE recurred in 3 patients during follow-up. Excluding patients diagnosed at the time of autopsy, 9% of patients died within 1 year of NBTE diagnosis. Conclusion NBTE was diagnosed pathologically in the presence of hyper-inflammatory states due to critical illness or immunological diseases. It was predominantly on the left side of the heart and was associated with embolic phenomena, either clinically or on imaging. Patients diagnosed with antemortem with NBTE have a high mortality in the first year (9%).