Effects of Concomitant CABG on Outcomes in Veterans Who Require Surgery for Endocarditis.

BACKGROUND: Infective Endocarditis (IE) is a complicated disease frequently accompanied by coronary artery disease (CAD) though no clear guidelines exist for when concomitant revascularization should be undertaken once valve surgery is indicated. Data on this topic within the United States (US) Veteran population, who have unique healthcare needs when compared to the civilian population, is sparse. We investigated the impact of concomitant coronary artery bypass grafting (CABG) on morbidity and mortality in US Veterans requiring surgical management of IE. METHODS: We identified 489 patients who underwent surgical management of IE between January 1 2010 and December 31 2020 at any of 43 Veterans Affairs (VA) cardiac surgery centers in the US. Patients were stratified based on who underwent concomitant CABG at the time of operation. Primary outcomes included the occurrence of postoperative myocardial infarction (MI), stroke, or mortality. Continuous variables were compared using independent t-tests or Mann Whitney U tests, and categorical variables were compared using the Chi square test. Cox proportional-hazard models were used to calculate risk for primary outcomes based on group. RESULTS: 61 patients (12.5%) underwent concomitant CABG for CAD. After adjusting for significant covariates, patients who underwent CABG had a higher long-term risk of MI (adjusted hazard ratios (aHR) 2.37, 95% CI: 1.29-4.35, p = 0.005) and higher risk of MI at 30-days (aHR 2.34, 95% CI: 1.06-5.19, p = 0.035). Concomitant CABG was not associated with long-term stroke or death, 30-day stroke or death, or perioperative complications. On sub-analysis of patients with moderate to severe CAD, rates of MI were higher in the CABG group at 30 days (25.9 vs. 3.4%, p = 0.016) and 1 year (33.3 vs. 3.4%, p = 0.004), though not long-term. The mean number of grafts was 1.51 ± 0.76, with only one graft performed in 65.6% (40/61) of patients. CONCLUSIONS: Concomitant CABG at the time of operation for IE was associated with increased risk of MI at 30-day and long-term, though most CABGs involved a low number of grafts. It was not associated with 30-day stroke or death, long term stroke or death, or perioperative complications. The optimal treatment of CAD noted during preoperative evaluation for veterans undergoing surgery for IE remains unclear.

Soft, bioresorbable, transparent microelectrode arrays for multimodal spatiotemporal mapping and modulation of cardiac physiology.

Transparent microelectrode arrays (MEAs) that allow multimodal investigation of the spatiotemporal cardiac characteristics are important in studying and treating heart disease. Existing implantable devices, however, are designed to support chronic operational lifetimes and require surgical extraction when they malfunction or are no longer needed. Meanwhile, bioresorbable systems that can self-eliminate after performing temporary functions are increasingly attractive because they avoid the costs/risks of surgical extraction. We report the design, fabrication, characterization, and validation of a soft, fully bioresorbable, and transparent MEA platform for bidirectional cardiac interfacing over a clinically relevant period. The MEA provides multiparametric electrical/optical mapping of cardiac dynamics and on-demand site-specific pacing to investigate and treat cardiac dysfunctions in rat and human heart models. The bioresorption dynamics and biocompatibility are investigated. The device designs serve as the basis for bioresorbable cardiac technologies for potential postsurgical monitoring and treating temporary patient pathological conditions in certain clinical scenarios, such as myocardial infarction, ischemia, and transcatheter aortic valve replacement.

Graphene Biointerface for Cardiac Arrhythmia Diagnosis and Treatment.

Heart rhythm disorders, known as arrhythmias, cause significant morbidity and are one of the leading causes of mortality. Cardiac arrhythmias are frequently treated by implantable devices, such as pacemakers and defibrillators, or by ablation therapy guided by electroanatomical mapping. Both implantable and ablation therapies require sophisticated biointerfaces for electrophysiological measurements of electrograms and delivery of therapeutic stimulation or ablation energy. In this work, a graphene biointerface for in vivo cardiac electrophysiology is reported for the first time. Leveraging sub-micrometer-thick tissue-conformable graphene arrays, sensing and stimulation of the open mammalian heart are demonstrated both in vitro and in vivo. Furthermore, the graphene biointerface treatment of atrioventricular block (the kind of arrhythmia where the electrical conduction from the atria to the ventricles is interrupted) is demonstrated. The graphene arrays show effective electrochemical properties, namely interface impedance down to 40 Ω cm2 at 1 kHz, charge storage capacity up to 63.7 mC cm-2 , and charge injection capacity up to 704 µC cm-2 . Transparency of the graphene structures allows for simultaneous optical mapping of cardiac action potentials, calcium transients, and optogenetic stimulation while performing electrical measurements and stimulation. The report presents evidence of the significant potential of graphene biointerfaces for advanced cardiac electrophysiology and arrhythmia therapy.

Open thoracic surgical implantation of cardiac pacemakers in rats.

Genetic engineering and implantable bioelectronics have transformed investigations of cardiovascular physiology and disease. However, the two approaches have been difficult to combine in the same species: genetic engineering is applied primarily in rodents, and implantable devices generally require larger animal models. We recently developed several miniature cardiac bioelectronic devices suitable for mice and rats to enable the advantages of molecular tools and implantable devices to be combined. Successful implementation of these device-enabled studies requires microsurgery approaches that reliably interface bioelectronics to the beating heart with minimal disruption to native physiology. Here we describe how to perform an open thoracic surgical technique for epicardial implantation of wireless cardiac pacemakers in adult rats that has lower mortality than transvenous implantation approaches. In addition, we provide the methodology for a full biocompatibility assessment of the physiological response to the implanted device. The surgical implantation procedure takes ~40 min for operators experienced in microsurgery to complete, and six to eight surgeries can be completed in 1 d. Implanted pacemakers provide programmed electrical stimulation for over 1 month. This protocol has broad applications to harness implantable bioelectronics to enable fully conscious in vivo studies of cardiovascular physiology in transgenic rodent disease models.

Risk factors for cerebrovascular accident after isolated coronary artery bypass grafting in Veterans.

BACKGROUND: Cerebrovascular accident (CVA) after coronary artery bypass grafting (CABG) is a devastating complication. Patient comorbidities and intraoperative elements contribute to the risk of CVA. The aim of this study is to identify risk factors for CVA in Veterans undergoing CABG. METHODS: Veterans undergoing isolated CABG from 2008 to 2019 were retrospectively identified using the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database. Thirty-day postoperative outcomes were observed. Univariate analysis followed by multivariable logistic regression identified independent risk factors for postoperative CVA. Receiver operating characteristic diagnostics identified optimal inflection points between continuous risk factors and odds of CVA. RESULTS: Twenty-eight thousand seven hundred fifty-seven patients met inclusion criteria. Incidence of CVA was 1.1% (310 cases). In multivariate analysis, preoperative cerebrovascular disease had the strongest association with postoperative CVA (adjusted odds ratio = 2.29; p < .001). There was an inverse relationship between CVA incidence and ejection fraction (EF), with EF of 35%-39% conferring a 2.11 times higher risk compared to EF >55% (p < .001). CVA incidence was not different in on-pump versus off-pump cases; however, after 104 min or more on bypass patients had a 55% greater adjusted odds of CVA (p < .001). Other risk factors included poor kidney function, prior myocardial infarction, and intra-aortic balloon pump use. CONCLUSION: The risk of CVA after CABG is multifactorial and involves multiple organ systems, including cardiac disease, poor renal function, and cerebrovascular disease, which was the strongest contributing risk factor. Optimization of these comorbidities and time on bypass may help improve clinical outcomes and lower the risk of this devastating complication.

Racial Disparities in 30-Day Outcomes After Colorectal Surgery in an Integrated Healthcare System.

BACKGROUND: Racial disparities in colorectal surgery outcomes have been studied extensively in the USA, and access to healthcare resources may contribute to these differences. The Veterans Health Administration (VHA) is the largest integrated healthcare network in the USA with the potential for equal access care to veterans. The objective of this study is to evaluate the VHA for the presence of racial disparities in 30-day outcomes of patients that underwent colorectal resection. METHODS: Colon and rectal resections from 2008 to 2019 were reviewed retrospectively using the Veterans Affairs Surgical Quality Improvement Program database. Patients were categorized by race and ethnicity. Multivariable analysis was used to compare 30-day outcomes. Cases with "unknown/other/declined to answer" race/ethnicity were excluded. RESULTS: Thirty-six-thousand-nine-hundred-sixty-nine cases met inclusion criteria: 27,907 (75.5%) Caucasian, 6718 (18.2%) African American, 2047 (5.5%) Hispanic, and 290 (0.8%) Native American patients. There were no statistically significant differences in overall complication incidence or mortality between all cohorts. Compared to Caucasian race, African American patients had longer mean length of stay (10.7 days vs. 9.7 days; p < 0.001). Compared to Caucasian race, Hispanic patients had higher odds of pulmonary-specific complications (adjusted odds ratio with 95% confidence interval = 1.39 [1.17-1.64]; p < 0.001). CONCLUSIONS: The VHA provides the benefits of integrated healthcare and access, which may explain the improvements in racial disparities compared to existing literature. However, some racial disparities in clinical outcomes still persisted in this analysis. Further efforts beyond healthcare access are needed to mitigate disparities in colorectal surgery. CLASSIFICATIONS: [Outcomes]; [Database]; [Veterans]; [Colorectal Surgery]; [Morbidity]; [Mortality].

Restrictive Intraoperative Fluid Rate is Associated with Improved Outcomes in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Management of patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CS/HIPEC) has historically favored liberal fluid administration owing to lengthy duration of surgery and hyperthermia. This practice has been challenged in recent years with studies demonstrating improved outcomes with restrictive fluid administration. METHODS: Patients who underwent CS/HIPEC between March 2010 and September 2018 were included for analysis. Patients who received an above-median fluid rate (high-IVF) versus below-median fluid rate (low-IVF) were compared, and multivariate analyses were performed for length of stay, 90-day unplanned readmissions, and major complications. RESULTS: The 167 patients had a mean age of 56.7 ± 11.4 years and body mass index of 29.5 ± 6.9 kg/m2. The median rate of total intraoperative crystalloid and colloid was 7.4 mL/kg/h. The low-IVF group had less blood loss (183 vs. 330 mL, p = 0.002), were less likely to need intraoperative vasopressor drip (2.4% vs. 11.9%, p = 0.018), and experienced fewer cardiac complications (2.4% vs. 10.7%, p = 0.031), pneumonias (0% vs. 6.0%, p = 0.024), and Clavien-Dindo grade 3-5 complications (14.5% vs. 33.3%, p = 0.004). Multivariate analyses identified bowel resection (HR 4.65, p = 0.0008) as a risk factor for 90-day unplanned readmission, while bowel resection, intraoperative fluid rate, and estimated blood loss were associated with increased length of stay. CONCLUSION: Higher intraoperative fluid intake was associated with multiple postoperative complications and increased length of stay, and represents a potentially avoidable risk factor for morbidity in CS/HIPEC.