The following is a summary of “Hematopoietic Somatic Mosaicism Is Associated With an Increased Risk of Postoperative Atrial Fibrillation,” published in the April 2023 issue of Cardiology by Ninni, et al.
During on-pump cardiac surgery, sterile inflammation triggers postoperative complications such as postoperative atrial fibrillation (POAF).
Hematopoietic somatic mosaicism (HSM) has recently been identified as a risk factor for cardiovascular diseases. It results in a shift toward a chronic proinflammatory monocyte transcriptome and phenotype. For a study, researchers sought to evaluate HSM’s prevalence, characteristics, and impact on preoperative blood and myocardial myeloid cells, as well as outcomes following cardiac surgery.
Blood DNA samples from 104 patients undergoing surgical aortic valve replacement (AVR) were genotyped using the HemePACT panel, which consists of 576 genes. Four different screening methods were employed to assess the presence of HSM, and postoperative outcomes were investigated. Selected patients underwent in-depth blood and myocardial leukocyte phenotyping using mass cytometry. Additionally, preoperative and postoperative RNA sequencing analysis of classical monocytes was performed.
The prevalence of HSM in the patient cohort ranged from 29% when considering the conventional HSM panel (97 genes) with variant allelic frequencies of 2% or higher to 60% when considering the full HemePACT panel with variant allelic frequencies of 1% or higher. Three out of four HSM definitions examined showed a significant association with a higher risk of POAF. Using the most inclusive definition, HSM carriers exhibited a 3.5-fold increased risk of POAF (age-adjusted odds ratio: 3.5; 95% CI: 1.52-8.03; P = 0.003) and an amplified inflammatory response following AVR. HSM carriers also demonstrated higher levels of activated CD64+CD14+CD16– circulating monocytes and inflammatory monocyte-derived macrophages in the myocardium before surgery.
HSM is prevalent among patients undergoing AVR and is associated with enriching proinflammatory cardiac monocyte-derived macrophages. It predisposes individuals to a higher incidence of POAF. The assessment of HSM may prove useful in personalized management during the perioperative period for these patients.