Troponin elevation in severe sepsis and septic shock: the role of left ventricular diastolic dysfunction and right ventricular dilatation*.

OBJECTIVE: Serum troponin concentrations predict mortality in almost every clinical setting they have been examined, including sepsis. However, the causes for troponin elevations in sepsis are poorly understood. We hypothesized that detailed investigation of myocardial dysfunction by echocardiography can provide insight into the possible causes of troponin elevation and its association with mortality in sepsis. DESIGN: Prospective, analytic cohort study. SETTING: Tertiary academic institute. PATIENTS: A cohort of ICU patients with severe sepsis or septic shock. INTERVENTIONS: Advanced echocardiography using global strain, strain-rate imaging and 3D left and right ventricular volume analyses in addition to the standard echocardiography, and concomitant high-sensitivity troponin-T measurement in patients with severe sepsis or septic shock. MEASUREMENTS AND MAIN RESULTS: Two hundred twenty-five echocardiograms and concomitant high-sensitivity troponin-T measurements were performed in a cohort of 106 patients within the first days of severe sepsis or septic shock (2.1 ± 1.4 measurements/patient). Combining echocardiographic and clinical variables, left ventricular diastolic dysfunction defined as increased mitral E-to-strain-rate e'-wave ratio, right ventricular dilatation (increased right ventricular end-systolic volume index), high Acute Physiology and Chronic Health Evaluation-II score, and low glomerular filtration rate best correlated with elevated log-transformed concomitant high-sensitivity troponin-T concentrations (mixed linear model: t = 3.8, 3.3, 2.8, and -2.1 and p = 0.001, 0.0002, 0.006, and 0.007, respectively). Left ventricular systolic dysfunction determined by reduced strain-rate s'-wave or low ejection fraction did not significantly correlate with log(concomitant high-sensitivity troponin-T). Forty-one patients (39%) died in-hospital. Right ventricular end-systolic volume index and left ventricular strain-rate e'-wave predicted in-hospital mortality, independent of Acute Physiology and Chronic Health Evaluation-II score (logistic regression: Wald = 8.4, 6.6, and 9.8 and p = 0.004, 0.010, and 0.001, respectively). Concomitant high-sensitivity troponin-T predicted mortality in univariate analysis (Wald = 8.4; p = 0.004), but not when combined with right ventricular end-systolic volume index and strain-rate e'-wave in the multivariate analysis (Wald = 2.3, 4.6, and 6.2 and p = 0.13, 0.032, and 0.012, respectively). CONCLUSIONS: Left ventricular diastolic dysfunction and right ventricular dilatation are the echocardiographic variables correlating best with concomitant high-sensitivity troponin-T concentrations. Left ventricular diastolic and right ventricular systolic dysfunction seem to explain the association of troponin with mortality in severe sepsis and septic shock.

The correlation between high-sensitivity troponin-T and cell-free cardiac DNA in the blood of patients undergoing noncardiac, predominantly vascular surgery.

OBJECTIVE: To present a novel method that uses an epigenetic fingerprint to measure changes in plasma concentrations of cardiac-specific cell-free DNA (CS-cfDNA) as a marker of myocardial cell death. METHODS: This prospective, analytic, observational comparative study included patients with heart disease or multiple risk factors for heart disease undergoing major noncardiac, mostly vascular surgery, requiring an arterial-line, and at least 24 h hospitalization in the post anaesthesia care unit or critical care unit after surgery. Blood samples were collected at least four times per patient to measure troponin-T (via high-sensitivity troponin-T test) and CS-cfDNA pre- and postoperatively. RESULTS: A total of 117 patients were included (group 1, 77 patients [66%] with low preoperative and postoperative troponin-T; group 2, 18 patients [15%] with low preoperative but increased postoperative troponin-T; group 3, 16 patients [14%] with high troponin-T both preoperatively and postoperatively; and group 4, six patients [5%] with elevated preoperative troponin-T that decreased postoperatively). The increase in CS-cfDNA after surgery was statistically significant only in group 2, which correlated with an increase in troponin-T in the same group. CONCLUSIONS: CS-cfDNA increased early postoperatively, particularly in patients with silent postoperative troponin elevation, and was correlated with an increase in troponin-T. These results may suggest that, in the subgroup of patients with postoperative elevated troponin, cardiomyocyte death indeed occurred.

Diastolic dysfunction and mortality in severe sepsis and septic shock.

AIMS: Systolic dysfunction in septic shock is well recognized and, paradoxically, predicts better outcome. In contrast, diastolic dysfunction is often ignored and its role in determining early mortality from sepsis has not been adequately investigated. METHODS AND RESULTS: A cohort of 262 intensive care unit patients with severe sepsis or septic shock underwent two echocardiography examinations early in the course of their disease. All clinical, laboratory, and survival data were prospectively collected. Ninety-five (36%) patients died in the hospital. Reduced mitral annular e'-wave was the strongest predictor of mortality, even after adjusting for the APACHE-II score, low urine output, low left ventricular stroke volume index, and lowest oxygen saturation, the other independent predictors of mortality (Cox's proportional hazards: Wald = 21.5, 16.3, 9.91, 7.0 and 6.6, P< 0.0001, <0.0001, 0.002, 0.008, and 0.010, respectively). Patients with systolic dysfunction only (left ventricular ejection fraction ≤50%), diastolic dysfunction only (e'-wave <8 cm/s), or combined systolic and diastolic dysfunction (9.1, 40.4, and 14.1% of the patients, respectively) had higher mortality than those with no diastolic or systolic dysfunction (hazard ratio = 2.9, 6.0, 6.2, P= 0.035, <0.0001, <0.0001, respectively) and had significantly higher serum levels of high-sensitivity troponin-T and N-terminal pro-B-type natriuretic peptide (NT-proBNP). High-sensitivity troponin-T was only minimally elevated, whereas serum levels of NT-proBNP were markedly elevated [median (inter-quartile range): 0.07 (0.02-0.17) ng/mL and 5762 (1001-15 962) pg/mL, respectively], though both predicted mortality even after adjusting for highest creatinine levels (Wald = 5.8, 21.4 and 2.3, P= 0.015, <0.001 and 0.13). CONCLUSION: Diastolic dysfunction is common and is a major predictor of mortality in severe sepsis and septic shock.

The DNA methylome of human vascular endothelium and its use in liquid biopsies.

BACKGROUND: Vascular endothelial cells (VECs) are an essential component of each tissue, contribute to multiple pathologies, and are targeted by important drugs. Yet, there is a shortage of biomarkers to assess VEC turnover. METHODS: To develop DNA methylation-based liquid biopsies for VECs, we determined the methylome of VECs isolated from freshly dissociated human tissues. FINDINGS: A comparison with a human cell-type methylome atlas yielded thousands of loci that are uniquely unmethylated in VECs. These sites are typically gene enhancers, often residing adjacent to VEC-specific genes. We also identified hundreds of genomic loci that are differentially methylated in organotypic VECs, indicating that VECs feeding specific organs are distinct cell types with a stable epigenetic identity. We established universal and lung-specific VEC markers and evaluated their presence in circulating cell-free DNA (cfDNA). Nearly 2.5% of cfDNA in the plasma of healthy individuals originates from VECs. Sepsis, graft versus host disease, and cardiac catheterization are associated with elevated levels of VEC-derived cfDNA, indicative of vascular damage. Lung-specific VEC cfDNA is selectively elevated in patients with chronic obstructive pulmonary disease (COPD) or lung cancer, revealing tissue-specific vascular turnover. CONCLUSIONS: VEC cfDNA biomarkers inform vascular dynamics in health and disease, potentially contributing to early diagnosis and monitoring of pathologies, and assessment of drug activity. FUNDING: This work was supported by the Beutler Research Program, Helmsley Charitable Trust, JDRF, Grail and the DON Foundation (to Y.D.). Y.D holds the Walter & Greta Stiel Chair in heart studies. B.G., R.S., J.M., D.N., T.K., and Y.D. filed patents on cfDNA analysis.

Prognostic value of troponin and creatine kinase muscle and brain isoenzyme measurement after noncardiac surgery: a systematic review and meta-analysis.

BACKGROUND: There is uncertainty regarding the prognostic value of troponin and creatine kinase muscle and brain isoenzyme measurements after noncardiac surgery. METHODS: The current study undertook a systematic review and meta-analysis. The study used six search strategies and included noncardiac surgery studies that provided data from a multivariable analysis assessing whether a postoperative troponin or creatine kinase muscle and brain isoenzyme measurement was an independent predictor of mortality or a major cardiovascular event. Independent investigators determined study eligibility and abstracted data in duplicate. RESULTS: Fourteen studies, enrolling 3,318 patients and 459 deaths, demonstrated that an increased troponin measurement after surgery was an independent predictor of mortality (odds ratio [OR] 3.4, 95% confidence interval [CI] 2.2-5.2), but there was substantial heterogeneity (I(2) = 56%). The independent prognostic capabilities of an increased troponin value after surgery in the 10 studies that assessed intermediate-term (≤ 12 months) mortality was an OR = 6.7 (95% CI 4.1-10.9, I(2) = 0%) and in the 4 studies that assessed long-term (more than 12 months) mortality was an OR = 1.8 (95% CI 1.4-2.3, I(2) = 0%; P < 0.001 for test of interaction). Four studies, including 1,165 patients and 202 deaths, demonstrated an independent association between an increased creatine kinase muscle and brain isoenzyme measurement after surgery and mortality (OR 2.5, 95% CI 1.5-4.0, I(2) = 4%). CONCLUSIONS: An increased troponin measurement after surgery is an independent predictor of mortality, particularly within the first year; limited data suggest an increased creatine kinase muscle and brain isoenzyme measurement also predicts subsequent mortality. Monitoring troponin measurements after noncardiac surgery may allow physicians to better risk stratify and manage their patients.

Risk to and resilience of the coronary heart disease patient during surgery.

PURPOSE OF REVIEW: Three topics are at the forefront of the investigation and treatment of patients with coronary artery disease (CAD) undergoing major noncardiac surgery: prophylactic perioperative beta-blockade (PPBB), prophylactic statins and prophylactic preoperative coronary revascularization (PCR). The purpose of the review is to summarize the investigational efforts in each one of these fields and to provide a subjective evaluation as to their impact on perioperative patient care. RECENT FINDINGS: The data on PPBB are still controversial. Most recent studies are observational with contradicting results on whether PPBB improves perioperative survival and whether chronic beta-blockade is better than beta-blockers added acutely postoperatively. The data on statins are still evolving and the main question remains whether the proven long-term pleiotrophic, plaque-stabilizing effects of statins translate into measurable improvements in hard outcome in the acute, perioperative setting. The data on PCR are also incomplete. The study that previously reported lack of any perioperative benefit to PCR now provides data that in selected patients PCR may nevertheless improve outcome. SUMMARY: These topics demonstrate how difficult it is to prove a significant change in outcome in high-risk CAD patients by prophylactic preoperative measures and that there is no alternative to clinical judgment and individualized patient care.

A long-term survival score improves preoperative prediction of survival following major vascular surgery.

BACKGROUND: In a previous study it has been shown that a long-term survival score (LTSS), composed of Lee's Revised Cardiac Risk Index (RCRI) criteria supplemented by age, preoperative electrocardiography (EKG) features, and all types of diabetes to the RCRI criteria, predicts long-term (3-15 years) survival after major vascular surgery. The present study aimed to investigate the performance of LTSS in predicting earlier survival (3 months-3 years) as compared with the RCRI. METHODS: Data from 921 consecutive patients undergoing major vascular surgery (624 patients at Hadassah Medical Center [HMC] and 296 patients in Beth Israel Deaconess Medical Center [BIDMC]) were collected retrospectively. The LTSS was seven points that included the five RCRI factors as well as age >65 years and ST-segment depression on preoperative EKG. Logistic regression and receiver operating characteristic curve (ROC) curve analyses were used to compare the 3 months-3 years mortality between the RCRI and LTSS. RESULTS: The Beth Israel Deaconess Medical Center patients were sicker than the Hadassah Medical Center patients, with higher RCRI (1.2 ± 1.0 vs. 0.81 ± 0.83, p < 0.001) and LTSS (2.6 ± 1.4 vs. 1.7 ± 1.2, p < 0.001) and higher 3-years mortality (36.3% vs. 20.7%, p = 0.005). The LTSS predicted mortality better than RCRI as measured by the area under the ROC curves at all time points between 6 months (0.66 ± 0.03 vs. 0.57 ± 0.04, p = 0.02) and 3 years (0.70 ± 0.02 vs. 0.61 ± 0.02, p < 0.0001) in both institutions, but not 3-months mortality. The LTSS also provided better discrimination between each adjacent two-risk score than the RCRI. CONCLUSIONS: Age >65 years, ST-segment depression on preoperative 12-lead EKG, and all types of diabetes added to the RCRI significantly improved the preoperative prediction of mortality after 6 months following major vascular surgery.

Carotid Endarterectomy in a Patient With Type 2 Myocardial Infarction During Preparation for Surgery: A Case Report.

We present a patient who was admitted for carotid endarterectomy due to tight carotid stenosis and recent amaurosis fugax. His medical history included significant coronary artery disease with stable angina pectoris, hypertension with wide pulse pressure, chronic renal failure, and anemia. During preparation for surgery, the patient developed type 2 myocardial infarction with prolonged chest pain, ST depressions on electrocardiogram, and significant troponin elevations. The patient posed a serious clinical dilemma whether to continue with surgery despite the type 2 myocardial infarction or postpone the surgery. We discuss the diagnostic tests and the decision-making processes that guided us in the preoperative period.

Non-invasive detection of human cardiomyocyte death using methylation patterns of circulating DNA.

Detection of cardiomyocyte death is crucial for the diagnosis and treatment of heart disease. Here we use comparative methylome analysis to identify genomic loci that are unmethylated specifically in cardiomyocytes, and develop these as biomarkers to quantify cardiomyocyte DNA in circulating cell-free DNA (cfDNA) derived from dying cells. Plasma of healthy individuals contains essentially no cardiomyocyte cfDNA, consistent with minimal cardiac turnover. Patients with acute ST-elevation myocardial infarction show a robust cardiac cfDNA signal that correlates with levels of troponin and creatine phosphokinase (CPK), including the expected elevation-decay dynamics following coronary angioplasty. Patients with sepsis have high cardiac cfDNA concentrations that strongly predict mortality, suggesting a major role of cardiomyocyte death in mortality from sepsis. A cfDNA biomarker for cardiomyocyte death may find utility in diagnosis and monitoring of cardiac pathologies and in the study of normal human cardiac physiology and development.

Monitoring liver damage using hepatocyte-specific methylation markers in cell-free circulating DNA.

Liver damage is typically inferred from serum measurements of cytoplasmic liver enzymes. DNA molecules released from dying hepatocytes are an alternative biomarker, unexplored so far, potentially allowing for quantitative assessment of liver cell death. Here we describe a method for detecting acute hepatocyte death, based on quantification of circulating, cell-free DNA (cfDNA) fragments carrying hepatocyte-specific methylation patterns. We identified 3 genomic loci that are unmethylated specifically in hepatocytes, and used bisulfite conversion, PCR, and massively parallel sequencing to quantify the concentration of hepatocyte-derived DNA in mixed samples. Healthy donors had, on average, 30 hepatocyte genomes/ml plasma, reflective of basal cell turnover in the liver. We identified elevations of hepatocyte cfDNA in patients shortly after liver transplantation, during acute rejection of an established liver transplant, and also in healthy individuals after partial hepatectomy. Furthermore, patients with sepsis had high levels of hepatocyte cfDNA, which correlated with levels of liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Duchenne muscular dystrophy patients, in which elevated AST and ALT derive from damaged muscle rather than liver, did not have elevated hepatocyte cfDNA. We conclude that measurements of hepatocyte-derived cfDNA can provide specific and sensitive information on hepatocyte death, for monitoring human liver dynamics, disease, and toxicity.

Comprehensive human cell-type methylation atlas reveals origins of circulating cell-free DNA in health and disease.

Methylation patterns of circulating cell-free DNA (cfDNA) contain rich information about recent cell death events in the body. Here, we present an approach for unbiased determination of the tissue origins of cfDNA, using a reference methylation atlas of 25 human tissues and cell types. The method is validated using in silico simulations as well as in vitro mixes of DNA from different tissue sources at known proportions. We show that plasma cfDNA of healthy donors originates from white blood cells (55%), erythrocyte progenitors (30%), vascular endothelial cells (10%) and hepatocytes (1%). Deconvolution of cfDNA from patients reveals tissue contributions that agree with clinical findings in sepsis, islet transplantation, cancer of the colon, lung, breast and prostate, and cancer of unknown primary. We propose a procedure which can be easily adapted to study the cellular contributors to cfDNA in many settings, opening a broad window into healthy and pathologic human tissue dynamics.

[Evolution of the surgical repair of thoracoabdominal aortic aneurysm].

BACKGROUND: Thoracoabdominal aortic aneurysm repair requires complex surgery. Clamping of the descending aorta during the operation results in organ malperfusion, ischemia, and in some cases, irreversible end-organ damage and death. Several methods for organ preservation during the operation evolved, resulting in decreased post-operative organ malfunction. Re-attachment of intercostal arteries, cerebrospinal fluid drainage, and temporary bypass of the clamped aorta and selective perfusion of the spinal cord, intestine, liver and kidneys are widely used during the operation. OBJECTIVES: To determine the impact of implementation of protective measures on the outcome of thoracoabdominal surgery over a decade. METHODS: Between March 1993 and March 2003, 11 patients (age 41-80 years, average 60 years) underwent thoracoabdominal aortic aneurysm repair in our hospital. Different methods for organ preservation were used during the operation. RESULTS: The early survival is 91%. One patient suffered from paraplegia and one from mild temporary paraparesis. Two patients died during the follow-up period (at 5 months from pneumonia and at 2 years from aortic arch rupture). CONCLUSIONS: Implementation of all adjuncts to protect the organs dependent on aortic perfusion may eliminate the ischemic consequences of aortic clamping.

Effects of synchronized cardiac assist device on cardiac energetics.

A novel physiological cardiac assist device (PCAD), the LEV RAM assist device, which is synchronized with the failing heart ejection, was developed to improve the failing heart systolic and diastolic functions and cardiac energetics. The PCAD uses a single short cannula, which is inserted into the beating left ventricle (LV) by means of a specially designed device. Blood is ejected from the PCAD into the LV after the opening of the aortic valve and augments the cardiac stroke work. The same amount of blood is withdrawn from the LV into the PCAD, through the same cannula, during the diastole. The study aims to test the effects of the PCAD on cardiac energetics and coronary blood flow. Adult normal sheep were anesthetized and the heart was exposed by left thoracotomy. Pressures transducers (Millar Instruments, Inc., Houston, TX) were inserted into the LV and aorta. LV volume was measured by sonocrystals (Sonometrics Corp., London, Ontario, Canada) and impedance catheter (CD Lycom, Argonstrat 116 Zoetermeer, 2718 SP The Netherlands). Flowmeters (transonic) measured the cardiac output (CO) and the coronary arteries (left anterior descending (LAD) and circumflex) flows. A thin cannula was inserted into the coronary sinus and the oxygen content of the LV and the coronary sinus were determined (AVOXimeter-1000). Pressure-volume loops, myocardial energetics, and coronary flow were measured. The displaced PCAD volume was 11 mL. Four different levels of assist were studied by changing the frequency of the assist: (1) assist beat after three successive regular beats [1:4], (2) assist every third beat [1:3], (3) alternate assist and normal beat [1:2], and (4) continuous assist [1:1]. Cardiac output (CO) and stroke volume (SV) increased proportionally with increasing frequency of assist. Systolic mechanical efficiency of the PCAD was above 90%. Simultaneously, the PCAD decreased the end-diastolic volume (EDV; diastolic unloading). The PCAD increased coronary flow and decreased cardiac arterial-venous O(2) difference. We conclude that the PCAD efficiently augments CO and stroke work, decreases preload, and decreases the coronary arterial-venous O(2) difference; all these may expedite cardiac reverse remodeling, and promote recovery of function and eventual easy explanation of the device.

Performance of department staff in the window between discovery of collapse to cardiac arrest team arrival.

INTRODUCTION: Guideline-directed therapy during the first minutes of resuscitation may be life saving. This study assessed the performance of American Heart Association (AHA) guidelines by trained departmental staff in the period between discovery of collapse and emergency team arrival. METHODS: Over a period of 24 months, departmental performance prior to the arrival of the emergency team (median 180 s) was assessed by debriefings conducted within 24h of each event in a 740-bed tertiary hospital with a dedicated certified resuscitation team. Outcome measures were failure to meet AHA treatment recommendations (primary) and return of spontaneous circulation (ROSC)/survival to hospital discharge (secondary). RESULTS: Two hundred and forty four events were included (216 patients). Mean age was 69+/-17 years; 45% were women. The underlying causes of collapse were mainly cardiac (39%) or respiratory (32%). Residents conducted most of the resuscitations (69%) prior to the arrival of the emergency team. Basic diagnostic measures such as assessments of pulse and rhythm were not performed in 19 and 33% of events. Therapeutic measures such as positive pressure ventilation, chest compressions and defibrillation were not provided according to the guidelines in 17, 12 and 44% of the events. ROSC occurred in 62% of events; 54% of VF/VT, 30% of asystole, 22% of PEA and 76% of bradyarrhythmias/severe bradycardias. Survival to hospital discharge was 37% overall and 41% for patients found in VF/VT (n=33). CONCLUSIONS: Trained departmental staff performed poorly in the moments between patient discovery and arrival of the emergency team. Since patient outcomes were comparable to those described in the literature, poor resuscitation performance may be commonplace in hospitals where ward personnel are expected to deliver advanced life support prior to arrival of the emergency team.