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Shernan, Stanton

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Shernan, Stanton
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    Duration of Postoperative Atrial Fibrillation After Cardiac Surgery Is Associated With Worsened Long-Term Survival
    (Elsevier BV, 2016) Sigurdsson, Martin I.; Longford, Nicholas T.; Heydarpour, Mahyar; Saddic, Louis; Chang, Tzuu-Wang; Fox, Amanda A.; Collard, Charles D.; Aranki, Sary; Shekar, Prem; Shernan, Stanton; Muehlschlegel, Jochen; Body, Simon
    Background. Studies of the effects of postoperative atrial fibrillation (poAF) on long-term survival are con- flicting, likely because of comorbidities that occur with poAF and the patient populations studied. Furthermore, the effects of poAF duration on long-term survival are poorly understood. Methods. We utilized a prospectively collected data- base on outcomes of cardiac surgery at a large tertiary care institution between August 2001 and December 2010 with survival follow-up through June 2015 to analyze long-term survival of patients with poAF. In addition, we identified patient- and procedure-related variables asso- ciated with poAF, and estimated overall comorbidity burden using the Elixhauser comorbidity index. Survival was compared between patients with poAF (n [ 513) and a propensity score matched control cohort, both for all patients and separately for subgroups of patients with poAF lasting less than 2 days (n [ 218) and patients with prolonged poAF (n [ 265). Postoperative atrial fibrillation (poAF) is observed in 26% to 32% of patients after isolated coronary artery bypass graft (CABG) surgery, and 30% to 50% of patients after isolated valve or combined valve and CABG sur- gery [1]. Several clinical risk factors for poAF have been identified, including older age [2, 3], male sex [2], and obesity [4]. Comorbidities such as history of prior atrial fibrillation (AF) [5], hypertension [3], congestive heart failure [5], chronic obstructive lung disease [5], and chronic kidney disease [6] have also been associated with poAF. Furthermore, valve repair or replacement and an increased aortic cross-clamp time also contribute to an increased risk of poAF [2, 5]. More recently, several Accepted for publication May 2, 2016. Address correspondence to Dr Body, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02115; email: scbody@partners.org. ! 2016 by The Society of Thoracic Surgeons Published by Elsevier Results. Patients with poAF were older and had a higher burden of comorbidities. Survival was signifi- cantly worse for patients with poAF than for the matched control group (hazard ratio 1.43, 95% confi- dence interval: 1.11 to 1.86). That was driven by decreased survival among patients with prolonged poAF (hazard ratio 1.97, 95% confidence interval: 1.37 to 2.80), whereas survival of patients with poAF for less than 2 days was not significantly different from that of matched controls (hazard ratio 0.91, 95% confidence interval: 0.60 to 1.39). Conclusions. After close matching based on comor- bidity burden, prolonged poAF is still associated with decreased survival. Therefore, vigilance is warranted in monitoring and treating patients with prolonged poAF after cardiac surgery.
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    Plasma Corin Decreases After Coronary Artery Bypass Graft Surgery and Is Associated With Postoperative Heart Failure: A Pilot Study
    (Elsevier BV, 2015) Barnet, Caryn S.; Liu, Xiaoxiao; Body, Simon; Collard, Charles D.; Shernan, Stanton; Muehlschlegel, Jochen; Jarolim, Petr; Fox, Amanda A.
    Objective: Corin is a natriuretic peptide-converting enzyme that cleaves precursor pro-B-type natriuretic peptide to active B-type natriuretic peptide (BNP) (diuretic, natriuretic, and vaso- dilatory properties). Increased plasma BNP is a known diag- nostic and prognostic heart failure (HF) biomarker in ambulatory and surgical patients. Recent studies indicate that plasma corin is decreased significantly in chronic HF patients, yet perioper- ative plasma corin concentrations have not been assessed in cardiac surgical patients. The objectives of this study were to determine the effect of coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) on plasma corin concentrations and to assess the association between change in perioperative plasma corin concentration and long-term postoperative HF hospitalization or death. It was hypothesized that plasma corin concentrations decrease significantly from preoperative baseline during postoperative days 1 to 4 and that hospitalization or death from HF during the 5 years after surgery is associated with higher relative difference (preoperative base- line to postoperative nadir) in plasma corin concentrations. Design: Prospective observational pilot study. Setting: Two institutions: Brigham and Women’s Hospi- tal, Boston, Massachusetts and the Texas Heart Institute, St. Luke’s Hospital, Houston, Texas. Participants: 99 patients of European ancestry who under- went isolated primary CABG surgery with CPB. Interventions: Nonemergency isolated primary CABG sur- gery with CPB. Measurements and Main Results: Plasma corin concen- tration was assessed preoperatively and at 4 postoperative time points (postoperative days 1-4). HF hospitalization or HF death events during the 5 years after surgery were identified by review of hospital and death records. Post- operative plasma corin concentrations were significantly lower than preoperative baseline concentrations (p o 0.0001). Perioperative corin concentrations were sig- nificantly higher in males than in females (p o 0.0001). Fifteen patients experienced long-term postoperative HF events. Patients who experienced HF hospitalization or HF death during study follow-up had significantly higher rela- tive difference in plasma corin concentration (preoperative baseline to postoperative nadir) than patients who did not experience HF events during study follow-up (p 1⁄4 0.03). Conclusions: Plasma corin concentrations decrease signif- icantly from preoperative concentrations after CABG sur- gery. HF hospitalization or HF death during the 5 years after CABG surgery with CPB is associated with larger relative decrease in plasma corin concentration from preoperative baseline. Further investigation is warranted to determine the role of corin in postoperative HF biology.
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    Intraoperative Evaluation of Transmitral Pressure Gradients after Edge-to-Edge Mitral Valve Repair
    (Public Library of Science, 2013) Hilberath, Jan N.; Eltzschig, Holger K.; Shernan, Stanton; Worthington, Andrea H.; Aranki, Sary; Nowak-Machen, Martina
    Objective: Edge-to-edge repair of the mitral valve (MV) has been described as a viable option used for the surgical management of mitral regurgitation (MR). Based on the significant changes in MV geometry associated with this technique, we hypothesized that edge-to-edge MV repairs are associated with higher intraoperative transmitral pressure gradients (TMPG) compared to conventional methods. Methods: Patient records and intraoperative transesophageal echocardiography (TEE) examinations of 552 consecutive patients undergoing MV repair at a single institution over a three year period were assessed. After separation from cardiopulmonary bypass (CPB), peak and mean TMPG were recorded for each patient and subsequently analyzed. Results: 84 patients (15%) underwent edge-to-edge MV repair. Peak and mean TMPG were significantly higher compared to gradients in patients undergoing conventional repairs: 10.7±0.5 mmHg vs 7.1±0.2 mmHg; P<0.0001 and 4.3±0.2 mmHg vs 2.8±0.1 mmHg; P<0.0001. Only patients with mean TMPG ≥7 mmHg (n = 9) required prompt reoperation for iatrogenic mitral stenosis (MS). No differences in peak and mean TMPG were observed among edge-to-edge repairs performed in isolation, compared to those performed in combination with annuloplasty: 11.0±0.7 mmHg vs 10.3±0.6 mmHg and 4.4±0.3 mmHg vs 4.3±0.3 mmHg. There were no differences in TMPG between various types of annuloplasty techniques used in combination with the edge-to-edge repairs. Conclusions: Edge-to-edge MV repairs are associated with higher intraoperative peak and mean TMPG after separation from CPB compared to conventional repair techniques. Unless gradients are severely elevated, these findings are not necessarily suggestive of iatrogenic MS. Thus, in the immediate postoperative period mildly elevated TMPG can be expected and tolerated after edge-to-edge mitral repairs.
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    The Long Noncoding RNA Landscape of the Ischemic Human Left Ventricle
    (Ovid Technologies (Wolters Kluwer Health), 2017) Saddic, Louis A.; Sigurdsson, Martin I.; Chang, Tzuu-Wang; Mazaika, Erica; Heydarpour, Mahyar; Shernan, Stanton; Seidman, Christine; Seidman, Jonathan; Aranki, Sary; Body, Simon; Muehlschlegel, Jochen
    Background—The discovery of functional classes of long noncoding RNAs (lncRNAs) has expanded our understanding of the variety of RNA species that exist in cells. In the heart, lncRNAs have been implicated in the regulation of development, ischemic and dilated cardiomyopathy, and myocardial infarction. Nevertheless, there is a limited description of expression profiles for these transcripts in human subjects. Methods and Results—We obtained left ventricular tissue from human patients undergoing cardiac surgery and used RNA sequencing to describe a lncRNA profile. We then identified a list of lncRNAs that were differentially expressed between pairs of samples before and after the ischemic insult of cardiopulmonary bypass. The expression of some of these lncRNAs correlates with ischemic time. Coding genes in close proximity to differentially expressed lncRNAs as well as coding genes that have coordinated expression with these lncRNAs are enriched in functional categories related to myocardial infarction including: heart function, metabolism, the stress response, and the immune system. Conclusions—We describe a list of lncRNAs that are differentially expressed after ischemia in the human heart. These genes are predicted to function in pathways consistent with myocardial injury. As a result, lncRNAs may serve as novel diagnostic and therapeutic targets for ischemic heart disease.
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    Post-operative atrial fibrillation examined using whole-genome RNA sequencing in human left atrial tissue
    (BioMed Central, 2017) Sigurdsson, Martin I; Saddic, Louis; Heydarpour, Mahyar; Chang, Tzuu-Wang; Shekar, Prem; Aranki, Sary; Couper, Gregory S; Shernan, Stanton; Muehlschlegel, Jochen; Body, Simon
    Background: Both ambulatory atrial fibrillation (AF) and post-operative AF (poAF) are associated with substantial morbidity and mortality. Analyzing the tissue-specific gene expression in the left atrium (LA) can identify novel genes associated with AF and further the understanding of the mechanism by which previously identified genetic variants associated with AF mediate their effects. Methods: LA free wall samples were obtained intraoperatively immediately prior to mitral valve surgery in 62 Caucasian individuals. Gene expression was quantified on mRNA harvested from these samples using RNA sequencing. An expression quantitative trait loci (eQTL) analysis was performed, comparing gene expression between different genotypes of 1.0 million genetic markers, emphasizing genomic regions and genes associated with AF. Results: Comparison of whole-genome expression between patients who later developed poAF and those who did not identified 23 differentially expressed genes. These included genes associated with the resting membrane potential modified by potassium currents, as well as genes within Wnt signaling and cyclic GMP metabolism. The eQTL analysis identified 16,139 cis eQTL relationships in the LA, including several involving genes and single nucleotide polymorphisms (SNPs) linked to AF. A previous relationship between rs3744029 and MYOZ1 expression was confirmed, and a novel relationship between rs6795970 and the expression of the SCN10A gene was identified. Conclusions: The current study is the first analysis of the human LA expression landscape using high-throughput RNA sequencing. Several novel genes and variants likely involved in AF pathogenesis were identified, thus furthering the understanding of how variants associated with AF mediate their effects via altered gene expression. Trial registration ClinicalTrials.gov ID: NCT00833313, registered 5. January 2009 Electronic supplementary material The online version of this article (doi:10.1186/s12920-017-0270-5) contains supplementary material, which is available to authorized users.
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    Allele-specific expression in the human heart and its application to postoperative atrial fibrillation and myocardial ischemia
    (BioMed Central, 2016) Sigurdsson, Martin I.; Saddic, Louis; Heydarpour, Mahyar; Chang, Tzuu-Wang; Shekar, Prem; Aranki, Sary; Couper, Gregory S.; Shernan, Stanton; Seidman, Jon G.; Body, Simon; Muehlschlegel, Jochen
    Background: Allele-specific expression (ASE) is differential expression of each of the two chromosomal alleles of an autosomal gene. We assessed ASE patterns in the human left atrium (LA, n = 62) and paired samples from the left ventricle (LV, n = 76) before and after ischemia, and tested the utility of differential ASE to identify genes associated with postoperative atrial fibrillation (poAF) and myocardial ischemia. Methods: Following genotyping from whole blood and whole-genome sequencing of LA and LV samples, we called ASE using sequences overlapping heterozygous SNPs using rigorous quality control to minimize false ASE calling. ASE patterns were compared between cardiac chambers and with a validation cohort from cadaveric tissue. ASE patterns in the LA were compared between patients who had poAF and those who did not. Changes in ASE in the LV were compared between paired baseline and post-ischemia samples. Results: ASE was found for 3404 (5.1%) and 8642 (4.0%) of SNPs analyzed in the LA and LV, respectively. Out of 6157 SNPs with ASE analyzed in both chambers, 2078 had evidence of ASE in both LA and LV (p < 0.0001). The SNP with the greatest ASE difference in the LA of patients with and without postoperative atrial fibrillation was within the gelsolin (GSN) gene, previously associated with atrial fibrillation in mice. The genes with differential ASE in poAF were enriched for myocardial structure genes, indicating the importance of atrial remodeling in the pathophysiology of AF. The greatest change in ASE between paired post-ischemic and baseline samples of the LV was in the zinc finger and homeodomain protein 2 (ZHX2) gene, a modulator of plasma lipids. Genes with differential ASE in ischemia were enriched in the ubiquitin ligase complex pathway associated with the ischemia-reperfusion response. Conclusions: Our results establish a pattern of ASE in the human heart, with a high degree of shared ASE between cardiac chambers as well as chamber-specific ASE. Furthermore, ASE analysis can be used to identify novel genes associated with (poAF) and myocardial ischemia. Electronic supplementary material The online version of this article (doi:10.1186/s13073-016-0381-1) contains supplementary material, which is available to authorized users.
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    Influence of Intraaortic Balloon Pump Counterpulsation on Transesophageal Echocardiography Derived Determinants of Diastolic Function
    (Public Library of Science, 2015) Nowak-Machen, Martina; Hilberath, Jan N.; Rosenberger, Peter; Schmid, Eckhard; Memtsoudis, Stavros G.; Angermair, Johannes; Tuli, Jayshree K.; Shernan, Stanton
    Introduction: Intraaortic balloon pump counterpulsation (IABP) is often used in patients with acute coronary syndrome for its favourable effects on left ventricular (LV) systolic function and coronary perfusion. However, the effects of IABP on LV diastolic function have not been comprehensively investigated. Acute diastolic dysfunction has been linked to increased morbidity and mortality. The aim of this study was to examine the influence of IABP on LV diastolic dysfunction using standard TEE derived parameters. Methods: Intraoperative TEE was performed in 10 patients (mean age 65 ± 11 yrs) undergoing urgent coronary artery bypass graft surgery (CABG), who had received an IABP preoperatively. TEE derived measures of diastolic dysfunction included early to late transmitral Doppler inflow velocity ratio (E/A), deceleration time (Dt), pulmonary venous systolic to diastolic Doppler velocity ratio (S/D), transmitral propagation velocity (Vp), and the ratio of early to late mitral annular tissue Doppler velocities (e’/a’). Statistical analyses included the Wilcoxon Sign-Rank test, and a p<0.05 was considered significant. Results: Transmitral inflow E/A ratios increased significantly from 0.86 to 1.07 (p < 0.05), while Dt decreased significantly from 218 to 180 ms (p < 0.05) with the use of IABP. Significant increases in Vp (34 cm/s to 43 cm/s; p < 0.05), and e’/a’ (0.58 to 0.71; p < 0.05) suggested a favourable influence of intraaortic counterpulsation on diastolic function. Conclusion: The use of perioperative IABP significantly improves TEE derived parameters of diastolic function consistent with a favourable impact on LV relaxation in cardiac surgery patients undergoing CABG.
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    Tricuspid annular plane systolic excursion (TAPSE) predicts poor outcome in patients undergoing acute pulmonary embolectomy
    (EDIMES Edizioni Internazionali Srl, 2015) Schmid, Eckhard; Hilberath, Jan N; Blumenstock, Gunnar; Shekar, Prem; Kling, Steffen; Shernan, Stanton; Rosenberger, Peter; Nowak-Machen, Martina
    Introduction: Right ventricular failure remains a major cause of mortality during acute pulmonary embolism. Right ventricular function can be assessed with transesophageal echocardiography. However, due to the complex right ventricular anatomy, only a few echocardiographic parameters are reliable and easily obtainable intraoperatively. Tricuspid annular plane systolic excursion is a validated parameter of global right ventricular function. Methods: Data from 81 patients with acute pulmonary embolus undergoing pulmonary embolectomy were evaluated. Transesophageal echocardiography derived parameters of right ventricular function were obtained and compared to tricuspid annular plane systolic excursion measurements. Patients were then divided into two groups (TAPSE < 18 mm and ≥18 mm). Results: The patient population consisted of 46 males and 35 females, mean age 61.0 ± 12.9 years. Patients in the TAPSE <18 mm group had significantly larger diastolic (p=0.0015) and systolic (p=0.0031) right ventricular diameters, lower right ventricular fractional area change (p=0.0065) and greater degrees of tricuspid regurgitation (p=0.0001) compared to patients with TAPSE ≥18 mm. In addition, all patients who needed intraoperative cardiopulmonary resuscitation (11/81) or died intraoperatively (8/81) belonged to the TAPSE <18 mm group. Logistic regression analysis confirmed TAPSE <18 mm as an independent risk factor for intraoperative cardiopulmonary resuscitation and death. Conclusions: Transesophageal echocardiography derived TAPSE is easily obtainable and correlates well with other standardized parameters of right ventricular function. TAPSE <18 mm is an independent predictor of intraoperative cardiopulmonary resuscitation and death in patients undergoing emergent pulmonary embolectomy.
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    Descending aortic calcification increases renal dysfunction and in-hospital mortality in cardiac surgery patients with intraaortic balloon pump counterpulsation placed perioperatively: a case control study
    (BioMed Central, 2012) Nowak-Machen, Martina; Rawn, James; Shekar, Prem; Mitani, Aya; Tuli, Sagun; Bingold, Tobias M; Lawlor, Garrett; Eltzschig, Holger K; Shernan, Stanton; Rosenberger, Peter
    Introduction: Acute kidney injury (AKI) after cardiac surgery increases length of hospital stay and in-hospital mortality. A significant number of patients undergoing cardiac surgical procedures require perioperative intra-aortic balloon pump (IABP) support. Use of an IABP has been linked to an increased incidence of perioperative renal dysfunction and death. This might be due to dislodgement of atherosclerotic material in the descending thoracic aorta (DTA). Therefore, we retrospectively studied the correlation between DTA atheroma, AKI and in-hospital mortality. Methods: A total of 454 patients were retrospectively matched to one of four groups: -IABP/-DTA atheroma, +IABP/-DTA atheroma, -IABP/+DTA atheroma, +IABP/+DTA atheroma. Patients were then matched according to presence/absence of DTA atheroma, presence/absence of IABP, performed surgical procedure, age, gender and left ventricular ejection fraction (LVEF). DTA atheroma was assessed through standard transesophageal echocardiography (TEE) imaging studies of the descending thoracic aorta. Results: Basic patient characteristics, except for age and gender, did not differ between groups. Perioperative AKI in patients with -DTA atheroma/+IABP was 5.1% versus 1.7% in patients with -DTA atheroma/-IABP. In patients with +DTA atheroma/+IABP the incidence of AKI was 12.6% versus 5.1% in patients with +DTA atheroma/-IABP. In-hospital mortality in patients with +DTA atheroma/-IABP was 3.4% versus 8.4% with +DTA atheroma/+IABP. In patients with +DTA atheroma/+IABP in hospital mortality was 20.2% versus 6.4% with +DTA atheroma/-IABP. Multivariate logistic regression identified DTA atheroma > 1 mm (P = *0.002, odds ratio (OR) = 4.13, confidence interval (CI) = 1.66 to 10.30), as well as IABP support (P = *0.015, OR = 3.04, CI = 1.24 to 7.45) as independent predictors of perioperative AKI and increased in-hospital mortality. DTA atheroma in conjunction with IABP significantly increased the risk of developing acute kidney injury (P = 0.0016) and in-hospital mortality (P = 0.0001) when compared to control subjects without IABP and without DTA atheroma. Conclusions: Perioperative IABP and DTA atheroma are independent predictors of perioperative AKI and in-hospital mortality. Whether adding an IABP in patients with severe DTA calcification increases their risk of developing AKI and mortality postoperatively cannot be clearly answered in this study. Nevertheless, when IABP and DTA are combined, patients are more likely to develop AKI and to die postoperatively in comparison to patients without IABP and DTA atheroma.
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    C-Reactive Protein Gene Variants Are Associated with Postoperative C-reactive Protein Levels After Coronary Artery Bypass Surgery
    (BioMed Central, 2009) Perry, Tjörvi E; Muehlschlegel, Jochen; Liu, Kuang-Yu; Fox, Amanda Arlene; Collard, Charles D; Body, Simon; Shernan, Stanton
    Background: Elevated baseline C-reactive protein (CRP) levels are associated with increased risk for developing cardiovascular disease. Several CRP gene variants have been associated with altered baseline CRP levels in ambulatory populations. However, the influence of CRP gene variants on CRP levels during inflammatory states, such as surgery, is largely unexplored. We describe the association between candidate CRP gene variants and postoperative plasma CRP levels in patients undergoing primary, elective coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB). Methods: Using a multicenter candidate gene association study design, we examined the association between seventeen candidate CRP single nucleotide polymorphisms (SNPs) and inferred haplotypes, and altered postoperative CRP levels in 604 patients undergoing CABG surgery with CPB. Perioperative CRP levels were measured immediately prior to surgery, post-CPB and on postoperative days (POD) 1–4. Results: CRP levels were significantly elevated at all postoperative time points when compared with preoperative levels (P < 0.0001). After adjusting for clinical covariates, the minor allele of the synonymous coding SNP, rs1800947 was associated with lower peak postoperative CRP levels (\(P = 2.4 × 10^{-4}\)) and lower CRP levels across all postoperative time points (\(P = 4.8 × 10^{-5}\)). rs1800947 remained highly significant after Bonferroni adjustment for multiple comparisons. Conclusion: We identified a CRP gene SNP associated with lower postoperative CRP levels in patients undergoing CABG surgery with CPB. Further investigation is needed to clarify the significance of this association between CRP gene variants and the acute-phase rise in postoperative CRP levels with regard to the risk of adverse postoperative outcomes.