A Dual Atrioventricular Approach to Repair Pseudoaneurysm after Mitral Valve Surgery.

Background Left ventricular pseudoaneurysm (LVPA) is an uncommon but potentially fatal complication following atrioventricular groove rupture. Case Description We present a patient with a massive LVPA involving the lateral commissure and under the mitral P3 segment following coronary artery bypass grafting and mitral valve (MV) repair. MV replacement and arteriovenous pseudoaneurysm were repaired by dual approach via the left atrium with excision of the previously dehisced mitral ring to expose the defect and patch repair the atrioventricular defect through the pseudoaneurysm free wall. Conclusion This is a rare case of a large subacute postoperative LVPA repaired by dual atrial-ventricular approach to treat a contained atrioventricular groove rupture.

Effects of preoperative pulmonary function on perioperative outcomes after robotic-assisted pulmonary lobectomy.

INTRODUCTION: Effects of pulmonary function test (PFT) results on perioperative outcomes were investigated after robotic-assisted video-thoracoscopic (RAVT) pulmonary lobectomy. METHODS: We retrospectively analyzed 706 consecutive patients who underwent RAVT lobectomy by one surgeon over 10.8 years. Preoperative (preop) forced expiratory volume in 1 s as a percent of predicted (FEV1%) was used to group patients as having normal FEV1% (≥80%) versus reduced FEV1% (<80%). Demographics, preop comorbidities, intraoperative (intraop) and postoperative (postop) complications, perioperative outcomes, and median survival time (MST) were compared across patients with normal vs. reduced FEV1% using Chi-Square (X2), Fisher's Exact test, Student's t-test, Kruskal-Wallis test, or Kaplan-Meier analysis respectively, with significance at p ≤ 0.05. Multivariable analysis was performed for perioperative outcomes to investigate the differences across patients in the FEV1% groups. RESULTS: There were 470 patients with normal FEV1% and 236 patients with reduced FEV1%. The two FEV1% groups did not differ in intraop or postop complication rates, except for higher postop other arrhythmia requiring intervention (p = 0.004), prolonged air leak >5 days (p = 0.002), mucous plug formation (p = 0.009), hypoxia (p < 0.001), and pneumonia (p = 0.002), and total postop complications (p < 0.001) in reduced-FEV1% patients. Reduced FEV1% correlated with increased intraop estimated blood loss (p < 0.0001) and skin-to-skin operative time (p < 0.0001). Median overall survival in patients with normal FEV1% was 93.20 months (95% CI: 76.5-126.0) versus 58.9 months (95% CI: 50.4-68.4) in patients with reduced FEV1% (p = 0.0004). CONCLUSION: Patients should have PFTs conducted before surgery to determine at-risk patients. However, RAVT pulmonary lobectomy is feasible and safe even in patients with reduced FEV1%.

A machine learning approach to high-risk cardiac surgery risk scoring.

INTRODUCTION: In patients undergoing high-risk cardiac surgery, the uncertainty of outcome may complicate the decision process to intervene. To augment decision-making, a machine learning approach was used to determine weighted personalized factors contributing to mortality. METHODS: American College of Surgeons National Surgical Quality Improvement Program was queried for cardiac surgery patients with predicted mortality ≥10% between 2012 and 2019. Multiple machine learning models were investigated, with significant predictors ultimately used in gradient boosting machine (GBM) modeling. GBM-trained data were then used for local interpretable model-agnostic explanations (LIME) modeling to provide individual patient-specific mortality prediction. RESULTS: A total of 194 patient deaths among 1291 high-risk cardiac surgeries were included. GBM performance was superior to other model approaches. The top five factors contributing to mortality in LIME modeling were preoperative dialysis, emergent cases, Hispanic ethnicity, steroid use, and ventilator dependence. LIME results individualized patient factors with model probability and explanation of fit. CONCLUSIONS: The application of machine learning techniques provides individualized predicted mortality and identifies contributing factors in high-risk cardiac surgery. Employment of this modeling to the Society of Thoracic Surgeons database may provide individualized risk factors contributing to mortality.

Orthotopic Heart Auto-Transplantation in a Swine Model.

BACKGROUND AND AIM: The porcine heart bears the best resemblance to the human heart and remains the preferred preclinical model for anatomical, physiological, and medical device studies. In an effort to study phenomena related strictly to ischemia reperfusion and donor preservation protocols, it is essential to avoid the immune responses related to allotransplantation. Orthotopic auto-transplantation is a unique strategy to the field of cardiac transplantation for ex vivo experimentation. Nevertheless, auto-transplantation carries its own technical challenges related to insufficient length of the great vessels that are to be transected and re-anastomosed. METHODS: A novel method for orthotopic cardiac auto-transplantation in the porcine model was developed and was described herein. Porcine models were used for ex vivo experimentation of a novel device to study ischemia reperfusion injury. RESULTS: A total of five porcine models were used for ex vivo experimentation of a novel device to mitigate ischemia reperfusion injury and determine effects of donor preservation. Modifications to routine cardiac transplantation protocols to allow for successful auto-transplantation are described. CONCLUSION: Orthotopic cardiac auto-transplantation in the porcine model is a plausible and technically feasible method for reliable study of ischemia reperfusion injury and donor preservation protocols. Here, we describe methods for both direct orthotopic porcine cardiac auto-transplantations as well as a simplified protocol that can be substituted for full surgical auto-transplantation for the studies of preservation of donor hearts.

JARID2 Functions as a Tumor Suppressor in Myeloid Neoplasms by Repressing Self-Renewal in Hematopoietic Progenitor Cells.

How specific genetic lesions contribute to transformation of non-malignant myeloproliferative neoplasms (MPNs) and myelodysplastic syndromes (MDSs) to secondary acute myeloid leukemia (sAML) are poorly understood. JARID2 is lost by chromosomal deletions in a proportion of MPN/MDS cases that progress to sAML. In this study, genetic mouse models and patient-derived xenografts demonstrated that JARID2 acts as a tumor suppressor in chronic myeloid disorders. Genetic deletion of Jarid2 either reduced overall survival of animals with MPNs or drove transformation to sAML, depending on the timing and context of co-operating mutations. Mechanistically, JARID2 recruits PRC2 to epigenetically repress self-renewal pathways in hematopoietic progenitor cells. These studies establish JARID2 as a bona fide hematopoietic tumor suppressor and highlight potential therapeutic targets.

Reprogrammable CRISPR/Cas9-based system for inducing site-specific DNA methylation.

Advances in sequencing technology allow researchers to map genome-wide changes in DNA methylation in development and disease. However, there is a lack of experimental tools to site-specifically manipulate DNA methylation to discern the functional consequences. We developed a CRISPR/Cas9 DNA methyltransferase 3A (DNMT3A) fusion to induce DNA methylation at specific loci in the genome. We induced DNA methylation at up to 50% of alleles for targeted CpG dinucleotides. DNA methylation levels peaked within 50 bp of the short guide RNA (sgRNA) binding site and between pairs of sgRNAs. We used our approach to target methylation across the entire CpG island at the CDKN2A promoter, three CpG dinucleotides at the ARF promoter, and the CpG island within the Cdkn1a promoter to decrease expression of the target gene. These tools permit mechanistic studies of DNA methylation and its role in guiding molecular processes that determine cellular fate.