Preoperative Tricuspid Regurgitation Is Associated With Long-Term Mortality and Is Graded More Severe Than Intraoperative Tricuspid Regurgitation

OBJECTIVES

To determine whether preoperative (preop) tricuspid regurgitation (TR) severity grade was associated with postoperative mortality, to examine the correlation between pre-op and intraoperative (intraop) TR grades, and to understand which TR grade had better prognostic predictability in cardiac surgery patients.

DESIGN

Retrospective.

SETTING

Single institution.

PARTICIPANTS

Patients.

INTERVENTIONS

Preop and intraop echocardiography TR grades of 4,232 patients who had undergone cardiac surgeries between 2004 and 2014 were examined.

MEASUREMENTS AND MAIN RESULTS

Kaplan-Meier curves and Cox proportional hazard models were used to determine the association between TR grades and the primary endpoint of all-cause mortality. The Wilcoxon signed-rank test and Spearman's rank correlation were analyzed to assess the similarity and correlation between preop and intraop-grade pairs. Multivariate logistic regression models of the area under the curve characteristics were compared for prognostic implications. Kaplan-Meier curves demonstrated a strong relationship between preop grades and survival. Multivariate models showed significantly increased mortality starting at mild preop TR (mild TR: hazard ratio [HR] 1.24; 95% CI 1.05-1.46, p = 0.013; moderate TR: HR 1.60; 95% CI 1.05-1.97, p < 0.001; severe TR: HR 2.50; 95% CI 1.74-3.58, p < 0.001). Preop TR grades were mostly higher than intraop grades. Spearman's correlation was 0.55 (p < 0.001). The area under the curves of preop and intraop TR-based models were almost identical (0.704 v 0.702 1-year mortality and 0.704 v 0.700 2-year mortality).

CONCLUSIONS

The authors found that echocardiographically-determined preop TR grade at the time of surgical planning was associated with long-term mortality, starting even at a mild grade. Preop grades were higher than intraop grades, with a moderate correlation. Preop and intraop grades exhibited similar prognostic implications.

Effect of concurrent mitral valve surgery for secondary mitral regurgitation upon mortality after aortic valve replacement or coronary artery bypass surgery

Objectives

It is uncertain whether concurrent mitral valve repair or replacement for moderate or greater secondary mitral regurgitation at the time of coronary artery bypass graft or aortic valve replacement surgery improves long-term survival.

Methods

Patients undergoing coronary artery bypass graft and/or aortic valve replacement surgery with moderate or greater secondary mitral regurgitation were reviewed. The effect of concurrent mitral valve repair or replacement upon long-term mortality was assessed while accounting for patient and operative characteristics and mitral regurgitation severity.

Results

Of 1,515 patients, 938 underwent coronary artery bypass graft or aortic valve replacement surgery alone and 577 underwent concurrent mitral valve repair or replacement. Concurrent mitral valve repair or replacement did not alter the risk of postoperative mortality for patients with moderate mitral regurgitation (hazard ratio = 0.93; 0.75-1.17) or more-than-moderate mitral regurgitation (hazard ratio = 1.09; 0.74-1.60) in multivariable regression. Patients with more-than-moderate mitral regurgitation undergoing coronary artery bypass graft-only surgery had a survival advantage from concurrent mitral valve repair or replacement in the first two postoperative years (P = 0.028) that did not persist beyond that time. Patients who underwent concurrent mitral valve repair or replacement had a higher rate of later mitral valve operation or reoperation over the five subsequent years (1.9% vs. 0.2%; P = 0.0014) than those who did not.

Conclusions

These observations suggest that mitral valve repair or replacement for more-than-moderate mitral regurgitation at the time of coronary artery bypass grafting may be reasonable in a suitably selected coronary artery bypass graft population but not for aortic valve replacement, with or without coronary artery bypass grafting. Our findings are supportive of 2021 European guidelines that severe secondary mitral regurgitation "should" or be "reasonabl[y]" intervened upon at the time of coronary artery bypass grafting but do not support 2020 American guidelines for performing mitral valve repair or replacement concurrent with aortic valve replacement, with or without coronary artery bypass grafting.

Identifying Patients Vulnerable to Inadequate Pain Resolution After Cardiac Surgery

Acute postoperative pain (APOP) is often evaluated through granular parameters, though monitoring postoperative pain using trends may better describe pain state. We investigated acute postoperative pain trajectories in cardiac surgical patients to identify subpopulations of pain resolution and elucidate predictors of problematic pain courses. We examined retrospective data from 2810 cardiac surgical patients at a single center. The k-means algorithm for longitudinal data was used to generate clusters of pain trajectories over the first 5 postoperative days. Patient characteristics were examined for association with cluster membership using ordinal and multinomial logistic regression. We identified 3 subgroups of pain resolution after cardiac surgery: 37.7% with good resolution, 44.2% with moderate resolution, and 18.2% exhibiting poor resolution. Type I diabetes (2.04 [1.00-4.16], p = 0.05), preoperative opioid use (1.65 [1.23-2.22], p = 0.001), and illicit drug use (1.89 [1.26-2.83], p = 0.002) elevated risk of membership into worse pain trajectory clusters. Female gender (1.72 [1.30-2.27], p < 0.001), depression (1.60 [1.03-2.50], p = 0.04) and chronic pain (3.28 [1.79-5.99], p < 0.001) increased risk of membership in the worst pain resolution cluster. This study defined 3 APOP resolution subgroups based on pain score trend after cardiac surgery and identified factors that predisposed patients to worse resolution. Patients with moderate or poor pain trajectory consumed more opioids and received them for longer before discharge. Future studies are warranted to determine if altering postoperative pain monitoring and management improve postoperative course of patients at risk of moderate or poor pain resolution.

Joint preoperative transthoracic and intraoperative transoesophageal echocardiographic assessment of functional mitral regurgitation severity provides better association with long-term mortality

OBJECTIVES

Functional mitral regurgitation (MR) is observed with ischaemic heart disease or aortic valve disease. Assessing the value of mitral valve repair or replacement (MVR/P) is complicated by frequent discordance between preoperative transthoracic echocardiographic (pTTE) and intraoperative transoesophageal echocardiographic (iTOE) assessment of MR severity. We examined the association of pTTE and iTOE with postoperative mortality in patients with or without MR, at the time of coronary artery bypass grafting (CABG) and/or aortic valve replacement without MVR/P.

METHODS

Medical records of 6629 patients undergoing CABG and/or aortic valve replacement surgery with or without functional MR and who did not undergo MVR/P were reviewed. MR severity assessed by pTTE and iTOE were examined for association with postoperative mortality using proportional hazards regression while accounting for patient and operative characteristics.

RESULTS

In 72% of 709 patients with clinically significant (moderate or greater) functional MR detected by pTTE, iTOE performed after induction of anaesthesia demonstrated a reduction in MR severity, while 2% of patients had increased severity of MR by iTOE. iTOE assessment of MR was better associated with long-term postoperative mortality than pTTE in patients with moderate MR [hazard ratio (HR) 1.31 (1.11-1.55) vs 1.02 (0.89-1.17), P-value for comparison of HR 0.025] but was not different for more than moderate MR [1.43 (0.96-2.14) vs 1.27 (0.80-2.02)].

CONCLUSIONS

In patients undergoing CABG and/or aortic valve replacement without MVR/P, these findings support intraoperative reassessment of MR severity by iTOE as an adjunct to pTTE in the prediction of mortality. Alone, these findings do not yet provide evidence for an operative strategy.

EACTA/SCA Recommendations for the Cardiac Anesthesia Management of Patients With Suspected or Confirmed COVID-19 Infection: An Expert Consensus From the European Association of Cardiothoracic Anesthesiology and Society of Cardiovascular Anesthesiologists With Endorsement From the Chinese Society of Cardiothoracic and Vascular Anesthesiology

The European Association of Cardiothoracic Anaesthesiology (EACTA) and the Society of Cardiovascular Anesthesiologists (SCA) aimed to create joint recommendations for the perioperative management of patients with suspected or proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection undergoing cardiac surgery or invasive cardiac procedures.

To produce appropriate recommendations, the authors combined the evidence from the literature review, reevaluating the clinical experience of routine cardiac surgery in similar cases during the Middle East Respiratory Syndrome (MERS-CoV) outbreak and the current pandemic with suspected coronavirus disease 2019 (COVID-19) patients, and the expert opinions through broad discussions within the EACTA and SCA. The authors took into consideration the balance between established procedures and the feasibility during the present outbreak. The authors present an agreement between the European and US practices in managing patients during the COVID-19 pandemic.

The recommendations take into consideration a broad spectrum of issues, with a focus on preoperative testing, safety concerns, overall approaches to general and specific aspects of preparation for anesthesia, airway management, transesophageal echocardiography, perioperative ventilation, coagulation, hemodynamic control, and postoperative care.

As the COVID-19 pandemic is spreading, it will continue to present a challenge for the worldwide anesthesiology community. To allow these recommendations to be updated as long as possible, the authors provided weblinks to international public and academic sources providing timely updated data.

This document should be the basis of future task forces to develop a more comprehensive consensus considering new evidence uncovered during the COVID-19 pandemic.

Intraoperative Hemodynamic and Echocardiographic Measurements Associated With Severe Right Ventricular Failure After Left Ventricular Assist Device Implantation

BACKGROUND

Severe right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation increases morbidity and mortality. We investigated the association between intraoperative right heart hemodynamic data, echocardiographic parameters, and severe versus nonsevere RVF.

METHODS

A review of LVAD patients between March 2013 and March 2016 was performed. Severe RVF was defined by the need for a right ventricular mechanical support device, inotropic, and/or inhaled pulmonary vasodilator requirements for >14 days. From a chart review, the right ventricular failure risk score was calculated and right heart hemodynamic data were collected. Pulmonary artery pulsatility index (PAPi) [(pulmonary artery systolic pressure - pulmonary artery diastolic pressure)/central venous pressure (CVP)] was calculated for 2 periods: (1) 30 minutes before cardiopulmonary bypass (CPB) and (2) after chest closure. Echocardiographic data were recorded pre-CPB and post-CPB by a blinded reviewer. Univariate logistic regression models were used to examine the performance of hemodynamic and echocardiographic metrics.

RESULTS

A total of 110 LVAD patients were identified. Twenty-five did not meet criteria for RVF. Of the remaining 85 patients, 28 (33%) met criteria for severe RVF. Hemodynamic factors associated with severe RVF included: higher CVP values after chest closure (18 ± 9 vs 13 ± 5 mm Hg; P = .0008) in addition to lower PAPi pre-CPB (1.2 ± 0.6 vs 1.7 ± 1.0; P = .04) and after chest closure (0.9 ± 0.5 vs 1.5 ± 0.8; P = .0008). Post-CPB echocardiographic findings associated with severe RVF included: larger right atrial diameter major axis (5.4 ± 0.9 vs 4.9 ± 1.0 cm; P = .03), larger right ventricle end-systolic area (22.6 ± 8.4 vs 18.5 ± 7.9 cm; P = .03), lower fractional area of change (20.2 ± 10.8 vs 25.9 ± 12.6; P = .04), and lower tricuspid annular plane systolic excursion (0.9 ± 0.2 vs 1.1 ± 0.3 cm; P = .008). Right ventricular failure risk score was not a significant predictor of severe RVF. Post-chest closure CVP and post-chest closure PAPi discriminated severe from nonsevere RVF better than other variables measured, each with an area under the curve of 0.75 (95% CI, 0.64-0.86).

CONCLUSIONS

Post-chest closure values of CVP and PAPi were significantly associated with severe RVF. Echocardiographic assessment of RV function post-CPB was weakly associated with severe RVF.

A Novel 3-Dimensional Approach for the Echocardiographic Evaluation of Mitral Valve Area After Repair for Degenerative Disease

BACKGROUND

Currently available 2-dimensional (2D) echocardiographic methods for accurately assessing the mitral valve orifice area (MVA) after mitral valve repair (MVr) are limited due to its complex 3-dimensional (3D) geometry. We compared repaired MVAs obtained with commonly used 2D and 3D echocardiographic methods to a 3D orifice area (3DOA), which is a novel echocardiographic measurement and independent of geometric assumptions.

METHODS

Intraoperative 2D and 3D transesophageal echocardiography (TEE) images from 20 adult cardiac surgery patients who underwent MVr for mitral regurgitation obtained immediately after repair were retrospectively reviewed. MVAs obtained by pressure half-time (PHT), 2D planimetry (2DP), and 3D planimetry (3DP) were compared to those derived by 3DOA.

RESULTS

MVAs (mean value ± standard deviation [SD]) after MVr were obtained by PHT (3 ± 0.6 cm), 2DP (3.58 ± 0.75 cm), 3D planimetry (3DP; 2.78 ± 0.74 cm), and 3DOA (2.32 ± 0.76 cm). MVAs obtained by the 3DOA method were significantly smaller compared to those obtained by PHT (mean difference, 0.68 cm; P = .0003), 2DP (mean difference, 1.26 cm; P < .0001), and 3DP (mean difference, 0.46 cm; P = .003). In addition, MVA defined as an area ≤1.5 cm was identified by 3DOA in 2 patients and by 3DP in 1 patient.

CONCLUSIONS

Post-MVr MVAs obtained using the novel 3DOA method were significantly smaller than those obtained by conventional echocardiographic methods and may be consistent with a higher incidence of MVA reduction when compared to 2D techniques. Further studies are still needed to establish the clinical significance of 3D echocardiographic techniques used to measure MVA after MVr.

Severity of tricuspid regurgitation is associated with long-term mortality

OBJECTIVES

To determine the association between intraoperative/presurgical grade of tricuspid regurgitation (TR) and mortality, and to determine whether surgical correction of TR correlated with an increased chance of survival compared with patients with uncorrected TR.

METHODS

The grade of TR assessed by intraoperative transesophageal echocardiography (TEE) before surgical intervention was reviewed for 23,685 cardiac surgery patients between 1990 and 2014. Cox proportional hazard regression models were used to determine association between grade of TR and the primary endpoint of all-cause mortality. Association between tricuspid valve (TV) surgery and survival was determined with Cox proportional hazard regression models after matching for grade of TR.

RESULTS

Kaplan-Meier survival curves demonstrated a relationship between all grades of TR. Multivariable analysis of the entire cohort demonstrated significantly increased mortality for moderate (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.1-1.4; P < .0001) and severe TR (HR, 2.02; 95% CI, 1.57-2.6; P < .0001). Mild TR displayed a trend for mortality (HR, 1.07; 95% CI, 0.99-1.16; P = .075). After matching for grade of TR and additional confounders, patients who underwent TV surgery had a statistically significant increased likelihood of survival (HR, 0.74; 95% CI, 0.61-0.91; P = .004).

CONCLUSIONS

Our study of more than 20,000 patients demonstrates that grade of TR is associated with increased risk of mortality after cardiac surgery. In addition, all patients who underwent TV surgery had a statistically significantly increased likelihood of survival compared with those with the same degree of TR who did not undergo TV surgery.

The Long Noncoding RNA Landscape of the Ischemic Human Left Ventricle

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 an 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 and 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.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00985049.

Joint analysis of left ventricular expression and circulating plasma levels of Omentin after myocardial ischemia

BACKGROUND

Omentin-1, also known as Intelectin-1 (ITLN1), is an adipokine with plasma levels associated with diabetes, obesity, and coronary artery disease. Recent studies suggest that ITLN1 can mitigate myocardial ischemic injury but the expression of ITLN1 in the heart itself has not been well characterized. The purpose of this study is to discern the relationship between the expression pattern of ITLN1 RNA in the human heart and the level of circulating ITLN1 protein in plasma from the same patients following myocardial ischemia.

METHODS

A large cohort of patients (n = 140) undergoing elective cardiac surgery for aortic valve replacement were enrolled in this study. Plasma and left ventricular biopsy samples were taken at the beginning of cardiopulmonary bypass and after an average of 82 min of ischemic cross clamp time. The localization of ITLN1 in epicardial adipose tissue (EAT) was also further characterized with immunoassays and cell fate transition studies.

RESULTS

mRNA expression of ITLN1 decreases in left ventricular tissue after acute ischemia in human patients (mean difference 280.48, p = 0.001) whereas plasma protein levels of ITLN1 increase (mean difference 5.24, p < 0.001). Immunohistochemistry localized ITLN1 to the mesothelium or visceral pericardium of EAT. Epithelial to mesenchymal transition in mesothelial cells leads to a downregulation of ITLN1 expression.

CONCLUSIONS

Myocardial injury leads to a decrease in ITLN1 expression in the heart and a corresponding increase in plasma levels. These changes may in part be due to an epithelial to mesenchymal transition of the cells that express ITLN1 following ischemia. Trial Registration Clinicaltrials.gov ID: NCT00985049.

Echocardiographic Assessment of Mitral Stenosis Orifice Area: A Comparison of a Novel Three-Dimensional Method Versus Conventional Techniques

BACKGROUND

A comprehensive evaluation of mitral stenosis (MS) severity commonly utilizes two-dimensional (2D) echocardiography techniques. However, the complex three-dimensional (3D) structure of the mitral valve (MV) poses challenges to accurate measurements of its orifice area by 2D imaging modalities. We aimed to assess MS severity by comparing measurements of the MV orifice area using conventional echocardiography methods to 3D orifice area (3DOA), a novel echocardiographic technique which minimizes geometric assumptions.

METHODS

Routine 2D and 3D intraoperative transesophageal echocardiographic images from 26 adult cardiac surgery patients with at least moderate rheumatic MS were retrospectively reviewed. Measurements of the MV orifice area obtained by pressure half-time (PHT), proximal isovelocity surface area (PISA), continuity equation, and 3D planimetry were compared to those acquired using 3DOA.

RESULTS

MV areas derived by PHT, PISA, continuity equation, 3D planimetry, and 3DOA (mean value ± standard deviation) were 1.12 ± 0.27, 1.03 ± 0.27, 1.16 ± 0.35, 0.97 ± 0.25, and 0.76 ± 0.21 cm, respectively. Areas obtained from the 3DOA method were significantly smaller than areas derived from PHT (mean difference 0.35 cm, P < .0001), PISA (mean difference: 0.28 cm, P = .0002), continuity equation (mean difference: 0.43 cm, P = .0015), and 3D planimetry (mean difference: 0.19 cm, P < .0001). MV 3DOAs also identified a significantly greater percentage of patients with severe MS (88%) compared to PHT (31%, P = .006), PISA (42%, P = .01), and continuity equation (39%, P = .017) but not in comparison to 3D planimetry (62%, P = .165).

CONCLUSIONS

Novel measures of the stenotic MV 3DOA in patients with rheumatic heart disease are significantly smaller than calculated values obtained by conventional methods and may be consistent with a higher incidence of severe MS compared to 2D techniques. Further investigation is warranted to determine the clinical relevance of 3D echocardiographic techniques used to measure MV area.

Aortic Atheroma Increases the Risk of Long-Term Mortality in 20,000 Patients

BACKGROUND

The association between long-term survival and aortic atheroma in cardiac surgical patients has not been comprehensively investigated. In this study we determine the relation between grade of atheroma and the risk of long-term mortality in a retrospective cohort of more than 20,000 patients undergoing cardiac operation during a 20-year period.

METHODS

We included 22,304 consecutive intraoperative transesophageal and epiaortic ultrasound examinations performed at Brigham and Women's Hospital between 1995 and 2014, with long-term follow-up. The extent of atheromatous disease recorded in each examination was used for analysis. Mortality data were obtained from our institution's data registry. Mortality analyses were done using Cox proportional hazard regression models with follow-up as a time scale. We repeated the analysis in a subgroup of 14,728 patients with more detailed demographic characteristics, including postoperative stroke, queried from the institutional Society of Thoracic Surgeons database.

RESULTS

A total of 7,722 mortality events and 872 stroke events occurred. Patients with atheromatous disease demonstrated a significant increase in mortality across all grades of severity, both for the ascending and descending aorta. This relation remained unchanged after adjusting for additional covariates. Adjustments for postoperative stroke resulted in only minimal attenuation in the risk of postoperative mortality related to aortic atheroma.

CONCLUSIONS

Aortic atheromatous disease of any grade in the ascending and descending aorta is a significant long-term risk of long-term, all-cause mortality in cardiac operation patients. This association remains independent of other conventional risk factors and is not related to postoperative cerebrovascular accidents.

Post-operative atrial fibrillation examined using whole-genome RNA sequencing in human left atrial tissue

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.

Allele-specific expression in the human heart and its application to postoperative atrial fibrillation and myocardial ischemia

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.

Myocardial Preconditioning: Characteristics, Mechanisms, and Clinical Applications

Perioperative myocardial ischemia and dysfunction re main prevalent after cardiac surgery despite the use of conventional measures to provide myocardial protec tion. Myocardial preconditioning is a powerful, endog enously regulated means of myocardial protection that may also have some clinical usage for patients undergo ing cardiac surgical procedures. The paradoxical con cept of using ischemia as a stimulus for myocardial protection has been studied extensively in animals and humans. The specific characteristics and constituents of preconditioning have been well identified. The mecha nism remains to be completely elucidated due to differ ences among species and experimental models. Some pharmacologic agents are capable of mimicking the classic mechanism of ischemic preconditioning. Pharma cologic and ischemic preconditioning may have signifi cant clinical use and therapeutic efficacy as a means of providing myocardial protection during cardiac surgery, especially in procedures that do not use cardioplegia and cardiopulmonary bypass, such as minimally inva sive coronary artery bypass grafting. This article re views the characteristics, mechanisms, potential clini cal applications, and therapeutic efficacy of myocardial preconditioning.

Predictive Genomics of Adverse Events After Cardiac Surgery

Significant, yet highly individual, thrombotic and inflammatory responses to surgery provide an excellent opportunity for insight into the genomic impact upon a patient's postoperative course. Cardiac surgery elicits the most profound perioperative disturbance and is associated with the highest incidence of adverse outcomes of any elective surgical procedure. Thus, cardiac surgical patients are an ideal population in which to evaluate the influence of complex traits on perioperative morbidity and mortality. This review describes the application of fundamental genetics upon the occurrence of adverse outcomes after cardiac surgery and cardiac transplantation. Specific emphases include a brief primer of the principles of genetics concentrating on the effects of variation within the human genome upon clinical outcomes and the differences between so-called Mendelian traits and complex traits. Four important clinical diseases dealt with in this review as examples of the impact of genetic factors on clinical outcomes are the genetics of heparin-induced thrombocytopenia, heart transplantation rejection and vasculopathy, atrial fibrillation, and infection.

Duration of Postoperative Atrial Fibrillation After Cardiac Surgery Is Associated With Worsened Long-Term Survival

BACKGROUND

Studies of the effects of postoperative atrial fibrillation (poAF) on long-term survival are conflicting, 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 database 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 associated 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).

RESULTS

Patients with poAF were older and had a higher burden of comorbidities. Survival was significantly worse for patients with poAF than for the matched control group (hazard ratio 1.43, 95% confidence 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 comorbidity burden, prolonged poAF is still associated with decreased survival. Therefore, vigilance is warranted in monitoring and treating patients with prolonged poAF after cardiac surgery.

Length Polymorphisms in Heme Oxygenase-1 and AKI after Cardiac Surgery

Heme oxygenase-1 (HO-1) catalyzes the degradation of heme, which may be involved in the pathogenesis of AKI. Length polymorphisms in the number of GT dinucleotide repeats in the HO-1 gene (HMOX1) promoter inversely associate with HMOX1 mRNA expression. We analyzed the association between allelic frequencies of GT repeats in the HMOX1 gene promoter and postoperative AKI in 2377 white patients who underwent cardiac surgery with cardiopulmonary bypass. We categorized patients as having the short allele (S; <27 GT repeats) or long allele (L; ≥27 GT repeats), and defined AKI as an increase in serum creatinine ≥0.3 mg/dl within 48 hours or ≥50% within 5 days, or the need for RRT. Compared with patients with the SS genotype, patients with the LL genotype had 1.58-fold (95% confidence interval, 1.06 to 2.34; P=0.02) higher odds of AKI. After adjusting for baseline and operative characteristics, the odds ratio for AKI per L allele was 1.26 (95% confidence interval, 1.05 to 1.50; P=0.01). In conclusion, longer GT repeats in the HMOX1 gene promoter associate with increased risk of AKI after cardiac surgery, consistent with heme toxicity as a pathogenic feature of cardiac surgery-associated AKI, and with HO-1 as a potential therapeutic target.

Integrated microRNA and mRNA responses to acute human left ventricular ischemia

MicroRNAs (miRNAs) play a significant role in ischemic heart disease. Animal models of left ventricular (LV) ischemia demonstrate a unique miRNA profile; however, these models have limitations in describing human disease. In this study, we performed next-generation miRNA and mRNA sequencing on LV tissue from nine patients undergoing cardiac surgery with cardiopulmonary bypass and cardioplegic arrest. Samples were obtained immediately after aortic cross clamping (baseline) and before aortic cross clamp removal (postischemic). Of 1,237 identified miRNAs, 21 were differentially expressed between baseline and postischemic LV samples including the upregulated miRNAs miR-339-5p and miR-483-3p and the downregulated miRNA miR-139-5p. Target prediction analysis of these miRNAs was integrated with mRNA expression from the same LV samples to identify anticorrelated miRNA-mRNA pairs. Gene enrichment studies of candidate mRNA targets demonstrated an association with cardiovascular disease, cell death, and metabolism. Therapeutics that intervene on these miRNAs and their downstream targets may lead to novel mechanisms of mitigating the damage caused by ischemic insults on the human heart.

Influence of intraaortic balloon pump counterpulsation on transesophageal echocardiography derived determinants of diastolic function

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.

Using next-generation RNA sequencing to examine ischemic changes induced by cold blood cardioplegia on the human left ventricular myocardium transcriptome

BACKGROUND

The exact mechanisms that underlie the pathological processes of myocardial ischemia in humans are unclear. Cardiopulmonary bypass with cardioplegic arrest allows the authors to examine the whole transcriptional profile of human left ventricular myocardium at baseline and after exposure to cold cardioplegia-induced ischemia as a human ischemia model.

METHODS

The authors obtained biopsies from 45 patients undergoing aortic valve replacement surgery at baseline and after an average of 79 min of cold cardioplegic arrest. Samples were RNA sequenced and analyzed with the Partek Genomics Suite (Partek Inc., St. Louis, MO) for differential expression. Ingenuity Pathway Analysis (Ingenuity Systems, Redwood City, CA) and Biobase ExPlain (Biobase GmbH, Wolfenbuettel, Germany) systems were used for functional and pathway analyses.

RESULTS

Of the 4,098 genes with a mean expression value greater than 5, 90% were down-regulated and 9.1% were up-regulated. Of those, 1,241 were significantly differentially expressed. Gene ontology analysis revealed significant down-regulation in immune inflammatory response and complement activation categories and highly consistent was the down-regulation of intelectin 1, proteoglycan, and secretory leukocyte peptidase inhibitor. Up-regulated genes of interest were FBJ murine osteosarcoma viral oncogene homolog and the hemoglobin genes hemoglobin α1 (HBA1) and hemoglobin β. In addition, analysis of transcription factor-binding sites revealed interesting targets in factors regulating reactive oxygen species production, apoptosis, immunity, cytokine production, and inflammatory response.

CONCLUSIONS

The authors have shown that the human left ventricle exhibits significant changes in gene expression in response to cold cardioplegia-induced ischemia during cardiopulmonary bypass, which provides great insight into the pathophysiology of ventricular ischemia, and thus, may help guide efforts to reduce myocardial damage during surgery.

Genetic and clinical risk prediction model for postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation (PoAF) is common after coronary artery bypass grafting. We previously showed that atrial fibrillation susceptibility single nucleotide polymorphisms (SNPs) at the chromosome 4q25 locus are associated with PoAF. Here, we tested the hypothesis that a combined clinical and genetic model incorporating atrial fibrillation risk SNPs would be superior to a clinical-only model.

METHODS AND RESULTS

We developed and externally validated clinical and clinical/genetic risk models for PoAF. The discovery and validation cohorts included 556 and 1164 patients, respectively. Clinical variables previously associated with PoAF and 13 SNPs at loci associated with atrial fibrillation in genome-wide association studies were considered. PoAF occurred in 30% and 29% of patients in the discovery and validation cohorts, respectively. In the discovery cohort, a logistic regression model with clinical factors had good discrimination, with an area under the receiver operator characteristic curve of 0.76. The addition of 10 SNPs to the clinical model did not improve discrimination (area under receiver operator characteristic curve, 0.78; P=0.14 for difference between the 2 models). In the validation cohort, the clinical model had good discrimination (area under the receiver operator characteristic curve, 0.69) and addition of genetic variables resulted in a marginal improvement in discrimination (area under receiver operator characteristic curve, 0.72; P<0.0001).

CONCLUSIONS

We developed and validated a model for the prediction of PoAF containing common clinical variables. Addition of atrial fibrillation susceptibility SNPs did not improve model performance. Tools to accurately predict PoAF are needed to risk stratify patients undergoing coronary artery bypass grafting and identify candidates for prophylactic therapies.

Emergent transesophageal echocardiography in hemodynamically unstable obstetric patients

BACKGROUND

The obstetric population has an increasing incidence of comorbid conditions. These, coupled with the possibility of acute embolic events involving air, amniotic fluid, and thrombus, increase the likelihood of hemodynamic instability. Although the utility of transesophageal echocardiography to guide management in cardiac and high-risk, non-cardiac surgical populations has been well established, the emergent use in critically-ill parturients has not been comprehensively evaluated.

METHODS

Using our departmental transesophageal echocardiography database of 28 293 examinations, parturients were identified who underwent emergent transesophageal echocardiography for evaluation of hemodynamic instability, including cardiac arrest, between January 1999 and March 2014. Transesophageal echocardiography findings and their impact on patient management were analyzed.

RESULTS

Ten peripartum patients were evaluated. Six patients became unstable during dilation and evacuation procedures; one after a forceps delivery; one during and one after cesarean delivery; and one during a postpartum laparotomy. Six patients proceeded to cardiac arrest; however, all women survived their initial operation and resuscitation. Transesophageal echocardiography was instrumental in determining the etiology and guiding resuscitation in all 10 patients including emergent cardiac surgical intervention with cardiopulmonary bypass (n=2). Seven patients survived to hospital discharge, but three died after experiencing neurologic complications.

CONCLUSIONS

Severe hemodynamic instability and cardiac arrest can occur in previously healthy parturients in pregnancy. Our data suggest that emergent transesophageal echocardiography is a valuable tool in determining the etiology and directing therapy of refractory hypotension or cardiac arrest in obstetric patients.

Tricuspid annular plane systolic excursion (TAPSE) predicts poor outcome in patients undergoing acute pulmonary embolectomy

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.

Plasma corin decreases after coronary artery bypass graft surgery and is associated with postoperative heart failure: a pilot study

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 vasodilatory properties). Increased plasma BNP is a known diagnostic 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 perioperative 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 baseline to postoperative nadir) in plasma corin concentrations.

DESIGN

Prospective observational pilot study.

SETTING

Two institutions: Brigham and Women's Hospital, Boston, Massachusetts and the Texas Heart Institute, St. Luke's Hospital, Houston, Texas.

PARTICIPANTS

99 patients of European ancestry who underwent isolated primary CABG surgery with CPB.

INTERVENTIONS

Nonemergency isolated primary CABG surgery with CPB.

MEASUREMENTS AND MAIN RESULTS

Plasma corin concentration 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. Postoperative plasma corin concentrations were significantly lower than preoperative baseline concentrations (p<0.0001). Perioperative corin concentrations were significantly higher in males than in females (p<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 relative difference in plasma corin concentration (preoperative baseline to postoperative nadir) than patients who did not experience HF events during study follow-up (p=0.03).

CONCLUSIONS

Plasma corin concentrations decrease significantly from preoperative concentrations after CABG surgery. 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.

Genetic Variants Associated With Atrial Fibrillation and PR Interval Following Cardiac Surgery

OBJECTIVE

The authors hypothesized that genetic association between atrial fibrillation (AF)-associated and PR-associated genetic loci was biologically mediated through slower conduction velocities for some or all of these loci.

DESIGN

Prospectively collected cohort study.

SETTING

Single tertiary care university hospital.

PARTICIPANTS

A total of 1227 Caucasian patients who underwent coronary artery bypass grafting (CABG).

INTERVENTIONS

A total of 677 single nucleotide polymorphisms previously associated with ambulatory AF or PR interval were tested for association with postoperative atrial fibrillation (poAF) and preoperative PR interval, maximum PR interval, maximum change in PR interval, and maximum change in PR interval from preoperative PR interval.

MEASUREMENTS AND MAIN RESULTS

The incidence of new-onset poAF was 31%. All of the PR interval variables were longer in the poAF cohort. Two variants on 1q21 and 12 on 4q25 were associated with poAF after adjustment for false discovery rate (FDR), but no variants were associated with PR interval variables after adjustment for FDR. Several variants were associated with both poAF and PR interval variables at p<0.05, but none of them remained significant after adjusting for FDR.

CONCLUSION

It was found that patients with poAF have significantly longer PR interval. Genetic variants in both the 1q21 and 4q25 regions associate with poAF after CABG surgery, but the authors were unable to find association between these variants and PR interval after adjusting for FDR.

Rescue transoesophageal echocardiography for refractory haemodynamic instability during transvenous lead extraction

AIMS

The rising number of cardiovascular implantable electronic devices has led to a steep increase in transvenous lead extractions (TLEs). Procedure-related, haemodynamically significant adverse events are uncommon during TLE yet remain an inevitable risk. While the use of transoesophageal echocardiography (TEE) as a guide to clinical decision-making during refractory circulatory instability has been well established, the specific utility of rescue TEE during TLE has not been comprehensively studied.

METHODS AND RESULTS

Twenty-six patients who required emergent TEE to determine the aetiology of intractable haemodynamic instability during TLE were evaluated. Pericardial effusion requiring urgent pericardiocentesis and/or cardiac surgical intervention was diagnosed by TEE in 10 patients, and progressed to cardiac arrest in 4 patients. Haemorrhagic shock developed in two patients suffering from femoral vein laceration and right haemothorax, respectively. One additional patient developed acute respiratory compromise and right ventricular dysfunction diagnosed by TEE, which necessitated prolonged post-operative intubation and inotropic therapy. In 14 patients, TEE excluded life-threatening cardiovascular injuries and enabled the pursuit of continued medical management. Two patients with reassuring TEE findings underwent intra-operative placement of chest tubes for pneumothorax. All the 26 patients were discharged from the hospital.

CONCLUSION

While TLE is a relatively safe procedure, life-threatening cardiovascular injuries remain a rare risk. In this study, the use of rescue TEE ruled out significant cardiovascular injuries in the majority of patients. Furthermore, rescue TEE had a substantial impact on the efficiency of determining the aetiology of refractory haemodynamic instability during TLE and thereby facilitated the timely initiation of definitive intervention.

Ischemic mitral regurgitation: mechanisms, intraoperative echocardiographic evaluation, and surgical considerations

Ischemic mitral regurgitation (IMR) is a subcategory of functional rather than organic, mitral valve (MV) disease. Whether reversible or permanent, left ventricular remodeling creates IMR that is complex and multifactorial. A comprehensive TEE examination in patients with IMR may have important implications for perioperative clinical decision making. Several TEE measures predictive of MV repair failure have been identified. Current practice among most surgeons is to typically repair the MV in patients with IMR. MV replacement is usually reserved for situations in which the valve cannot be reasonably repaired, or repair is unlikely to be tolerated clinically.

Increased perioperative b-type natriuretic peptide associates with heart failure hospitalization or heart failure death after coronary artery bypass graft surgery

BACKGROUND

Heart failure (HF) is a leading cause of hospitalization and mortality. Plasma B-type natriuretic peptide (BNP) is an established diagnostic and prognostic ambulatory HF biomarker. We hypothesized that increased perioperative BNP independently associates with HF hospitalization or HF death up to 5 yr after coronary artery bypass graft surgery.

METHODS

The authors conducted a two-institution, prospective, observational study of 1,025 subjects (mean age = 64 ± 10 yr SD) undergoing isolated primary coronary artery bypass graft surgery with cardiopulmonary bypass. Plasma BNP was measured preoperatively and on postoperative days 1-5. The study outcome was hospitalization or death from HF, with HF events confirmed by reviewing hospital and death records. Cox proportional hazards analyses were performed with multivariable adjustments for clinical risk factors. Preoperative and peak postoperative BNP were added to the multivariable clinical model in order to assess additional predictive benefit.

RESULTS

One hundred five subjects experienced an HF event (median time to first event = 1.1 yr). Median follow-up for subjects who did not have an HF event = 4.2 yr. When individually added to the multivariable clinical model, higher preoperative and peak postoperative BNP concentrations each, independently associated with the HF outcome (log10 preoperative BNP hazard ratio = 1.93; 95% CI, 1.30-2.88; P = 0.001; log10 peak postoperative BNP hazard ratio = 3.38; 95% CI, 1.45-7.65; P = 0.003).

CONCLUSIONS

Increased perioperative BNP concentrations independently associate with HF hospitalization or HF death during the 5 yr after primary coronary artery bypass graft surgery. Clinical trials may be warranted to assess whether medical management focused on reducing preoperative and longitudinal postoperative BNP concentrations associates with decreased HF after coronary artery bypass graft surgery.

Complement activation and cardiac surgery: a novel target for improving outcomes

Complement activation and the resulting inflammatory response is an important potential mechanism for multisystem organ injury in cardiac surgery. Novel therapeutic strategies using complement inhibitors may hold promise for improving outcomes for cardiac surgical patients by attenuating complement activation or its biologically active effector molecules. Recent clinical trials evaluating complement inhibitors have provided important data to further delineate the impact of complement activation and its inhibition on clinical outcomes. In this review we examine the role of complement activation and its inhibition as a therapeutic approach in cardiac surgery.

Polymorphism in the protease-activated receptor-4 gene region associates with platelet activation and perioperative myocardial injury

Protease-activated receptors (PAR)-1 and -4 are the principal receptors for thrombin-mediated platelet activation. Functional genetic variation has been described in the human PAR1 gene, but not in the PAR4 gene (F2RL3). We sought to identify variants in and around F2RL3 and to determine their association with perioperative myocardial injury (PMI) after coronary artery bypass graft surgery. We further explored possible mechanisms for F2RL3 single nucleotide polymorphism (SNP) associations with PMI including altered receptor expression and platelet activation. Twenty-three SNPs in the F2RL3 gene region were genotyped in two phases in 934 Caucasian subjects. Platelets from 43 subjects (23 major allele, 20 risk allele) homozygous for rs773857 (SNP with the strongest association with PMI) underwent flow cytometry to assess PAR4 receptor number and response to activation by a specific PAR4 activating peptide (AYPGKF) measured by von Willebrand factor (vWf) binding and P-selectin release and PAC-1 binding. We identified a novel association of SNP rs773857 with PMI (OR = 2.4, P = 0.004). rs773857 risk allele homozygotes have significantly increased platelet counts and platelets showed a significant increase in P-selectin release after activation (P = 0.004). We conclude that rs773857 risk allele homozygotes are associated with risk for increased platelet count and hyperactivity.