Guide to Lung-Protective Ventilation in Cardiac Patients.

The incidence of acute respiratory insufficiency has continued to increase among patients admitted to modern-day cardiovascular intensive care units. Positive pressure ventilation (PPV) remains the mainstay of treatment for these patients. Alterations in intrathoracic pressure during PPV has distinct effects on both the right and left ventricles, affecting cardiovascular performance. Lung-protective ventilation (LPV) minimizes the risk of further lung injury through ventilator-induced lung injury and, hence, an understanding of LPV and its cardiopulmonary interactions is beneficial for cardiologists.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.

AIM: The executive summary of the American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions coronary artery revascularization guideline provides the top 10 items readers should know about the guideline. In the full guideline, the recommendations replace the 2011 coronary artery bypass graft surgery guideline and the 2011 and 2015 percutaneous coronary intervention guidelines. This summary offers a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization, as well as the supporting documentation to encourage their use. METHODS: A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered. Structure: Recommendations from the earlier percutaneous coronary intervention and coronary artery bypass graft surgery guidelines have been updated with new evidence to guide clinicians in caring for patients undergoing coronary revascularization. This summary includes recommendations, tables, and figures from the full guideline that relate to the top 10 take-home messages. The reader is referred to the full guideline for graphical flow charts, supportive text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in the development of this guideline.

The impact of a statewide payment reform on transcatheter aortic valve replacement (TAVR) utilization and readmissions.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an increasingly used but relatively expensive procedure with substantial associated readmission rates. It is unknown how cost-constrictive payment reform measures, such as Maryland's All Payer Model, impact TAVR utilization given its relative expense. This study investigated the impact of Maryland's All Payer Model on TAVR utilization and readmissions among Maryland Medicare beneficiaries. METHODS: This was a quasi-experimental investigation of Maryland Medicare patients undergoing TAVR between 2012 and 2018. New Jersey data were used for comparison. Longitudinal interrupted time series analyses were used to study TAVR utilization and difference-in-differences analyses were used to investigate post-TAVR readmissions. RESULTS: During the first year of payment reform (2014), TAVR utilization among Maryland Medicare beneficiaries dropped by 8% (95% confidence interval [CI]: -9.2% to -7.1%; p < 0.001), with no concomitant change in TAVR utilization in New Jersey (0.2%, 95% CI: 0%-1%, p = 0.09). Longitudinally, however, the All Payer Model did not impact TAVR utilization in Maryland compared to New Jersey. Difference-in-differences analyses demonstrated that implementation of the All Payer Model was not associated with significantly greater declines in 30-day post-TAVR readmissions in Maryland versus New Jersey (-2.1%; 95% CI: -5.2% to 0.9%; p =0.1). CONCLUSIONS: Maryland's All Payer Model resulted in an immediate decline in TAVR utilization, likely a result of hospitals adjusting to global budgeting. However, beyond this transition period, this cost-constrictive reform measure did not limit Maryland TAVR utilization. In addition, the All Payer Model did not reduce post-TAVR 30-day readmissions. These findings may help inform expansion of globally budgeted healthcare payment structures.

Myocardial Injury in Severe COVID-19 Compared With Non-COVID-19 Acute Respiratory Distress Syndrome.

BACKGROUND: Knowledge gaps remain in the epidemiology and clinical implications of myocardial injury in coronavirus disease 2019 (COVID-19). We aimed to determine the prevalence and outcomes of myocardial injury in severe COVID-19 compared with acute respiratory distress syndrome (ARDS) unrelated to COVID-19. METHODS: We included intubated patients with COVID-19 from 5 hospitals between March 15 and June 11, 2020, with troponin levels assessed. We compared them with patients from a cohort study of myocardial injury in ARDS and performed survival analysis with primary outcome of in-hospital death associated with myocardial injury. In addition, we performed linear regression to identify clinical factors associated with myocardial injury in COVID-19. RESULTS: Of 243 intubated patients with COVID-19, 51% had troponin levels above the upper limit of normal. Chronic kidney disease, lactate, ferritin, and fibrinogen were associated with myocardial injury. Mortality was 22.7% among patients with COVID-19 with troponin under the upper limit of normal and 61.5% for those with troponin levels >10 times the upper limit of normal (P<0.001). The association of myocardial injury with mortality was not statistically significant after adjusting for age, sex, and multisystem organ dysfunction. Compared with patients with ARDS without COVID-19, patients with COVID-19 were older and had higher creatinine levels and less favorable vital signs. After adjustment, COVID-19-related ARDS was associated with lower odds of myocardial injury compared with non-COVID-19-related ARDS (odds ratio, 0.55 [95% CI, 0.36-0.84]; P=0.005). CONCLUSIONS: Myocardial injury in severe COVID-19 is a function of baseline comorbidities, advanced age, and multisystem organ dysfunction, similar to traditional ARDS. The adverse prognosis of myocardial injury in COVID-19 relates largely to multisystem organ involvement and critical illness.

Trends in Therapy and Outcomes Associated With Respiratory Failure in Patients Admitted to the Cardiac Intensive Care Unit.

PURPOSE: To describe the epidemiology, outcomes, and temporal trends of respiratory failure in the cardiac intensive care unit (CICU). MATERIALS AND METHODS: Retrospective cohort analysis of 2,986 unique Mayo Clinic CICU patients from 2007 to 2018 with respiratory failure. Temporal trends were analyzed, along with hospital and 1-year mortality. Multivariable logistic regression was used to determine adjusted hospital mortality trends. RESULTS: The prevalence of respiratory failure in the CICU increased from 15% to 38% during the study period (P < 0.001 for trend). Among patients with respiratory failure, the utilization of invasive ventilation decreased and noninvasive ventilation modalities increased over time. Hospital mortality and 1-year mortality were 24% and 54%, respectively, with variation according to the type of respiratory support (highest among patients receiving invasive ventilation alone: 35% and 46%, respectively). Hospital mortality was highest among patients with concomitant cardiac arrest and/or shock (52% for patients with both). Hospital mortality decreased in the overall population from 35% to 25% (P < 0.001 for trend), but was unchanged among patients receiving positive-pressure ventilation. CONCLUSIONS: The prevalence of respiratory failure in CICU more than doubled during the last decade. The use of noninvasive respiratory support increased, while overall mortality declined over time. Cardiac arrest and shock accounted for the majority of deaths. Further research is needed to optimize the outcomes of high-risk CICU patients with respiratory failure.

Center Variation in Use of Preoperative Dual Antiplatelet Therapy and Platelet Function Testing at the Time of Coronary Artery Bypass Grafting in Maryland.

BACKGROUND: Patients presenting with acute coronary syndrome are administered a P2Y 12 inhibitor and aspirin before coronary catheterization to prevent further myocardial injury from thrombosis. Guidelines recommend a standard waiting period between the time patients are administered dual antiplatelet therapy (DAPT) and elective cardiac surgery. Since 25% to 30% of the population may be considered nonresponders to clopidogrel, platelet function testing can be utilized for timing of surgery and to assess bleeding risks. The extent to which a standard waiting period or platelet function testing is used across centers is not established, representing an important opportunity to standardize practice. METHODS: We conducted a retrospective cohort study from 2011 to 2020 using data from the Maryland Cardiac Surgical Quality Initiative, a consortium of all 10 hospitals in the state performing cardiac surgery. The proportion of patients administered DAPT within 5 days of surgery was examined by hospital over the time period. Mixed-effects multivariable logistic regressions were used to examine the association of preoperative DAPT with ischemic and bleeding outcomes. Centers were surveyed on use or nonuse of preoperative platelet function testing, and bleeding outcomes were compared. RESULTS: There was significant heterogeneity of preoperative DAPT usage across centers ranging from 2% to 54% ( P < .001). DAPT within 5 days of isolated coronary artery bypass grafting (CABG) was associated with higher odds of reoperation for bleeding (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.19-2.01; P = .001), >2 units of red blood cells (RBCs) transfused (OR, 1.62; 95% CI, 1.44-1.81; P < .001), and >2 units of non-RBCs transfused (OR, 1.79; 95% CI, 1.60-2.00; P < .001). In the 5 hospitals using preoperative platelet function testing to guide timing of surgery, there were greater odds for DAPT within 5 days (OR, 1.33; 95% CI, 1.22-1.45; P < .001), fewer RBCs >2 units transfusions (22% vs 33%; P < .001), and non-RBCs >2 units (17% vs 28%; P < .001) transfusions within DAPT patients. CONCLUSIONS: There is significant variability in DAPT usage within 5 days of CABG between hospital centers. Preoperative platelet function testing may allow for earlier timing of surgery for those on DAPT without increased bleeding risks.

Unsupervised machine learning demonstrates the prognostic value of TAPSE/PASP ratio among hospitalized patients with COVID-19.

BACKGROUND: The ratio of tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) is a validated index of right ventricular-pulmonary arterial (RV-PA) coupling with prognostic value. We determined the predictive value of TAPSE/PASP ratio and adverse clinical outcomes in hospitalized patients with COVID-19. METHODS: Two hundred and twenty-nine consecutive hospitalized racially/ethnically diverse adults (≥18 years of age) admitted with COVID-19 between March and June 2020 with clinically indicated transthoracic echocardiograms (TTE) that included adequate tricuspid regurgitation (TR) velocities for calculation of PASP were studied. The exposure of interest was impaired RV-PA coupling as assessed by TAPSE/PASP ratio. The primary outcome was in-hospital mortality. Secondary endpoints comprised of ICU admission, incident acute respiratory distress syndrome (ARDS), and systolic heart failure. RESULTS: One hundred and seventy-six patients had both technically adequate TAPSE measurements and measurable TR velocities for analysis. After adjustment for age, sex, BMI, race/ethnicity, diabetes mellitus, and smoking status, log(TAPSE/PASP) had a significantly inverse association with ICU admission (p = 0.015) and death (p = 0.038). ROC analysis showed the optimal cutoff for TAPSE/PASP for death was 0.51 mm mmHg-1 (AUC = 0.68). Unsupervised machine learning identified two groups of echocardiographic function. Of all echocardiographic measures included, TAPSE/PASP ratio was the most significant in predicting in-hospital mortality, further supporting its significance in this cohort. CONCLUSION: Impaired RV-PA coupling, assessed noninvasively via the TAPSE/PASP ratio, was predictive of need for ICU level care and in-hospital mortality in hospitalized patients with COVID-19 suggesting utility of TAPSE/PASP in identification of poor clinical outcomes in this population both by traditional statistical and unsupervised machine learning based methods.

The Range of Cardiogenic Shock Survival by Clinical Stage: Data From the Critical Care Cardiology Trials Network Registry.

OBJECTIVES: Cardiogenic shock presents with variable severity. Categorizing cardiogenic shock into clinical stages may improve risk stratification and patient selection for therapies. We sought to determine whether a structured implementation of the 2019 Society for Cardiovascular Angiography and Interventions clinical cardiogenic shock staging criteria that is ascertainable in clinical registries discriminates mortality in a contemporary population with or at-risk for cardiogenic shock. DESIGN: We developed a pragmatic application of the Society for Cardiovascular Angiography and Interventions cardiogenic shock staging criteria-A (at-risk), B (beginning), C (classic cardiogenic shock), D (deteriorating), or E (extremis)-and examined outcomes by stage. SETTING: The Critical Care Cardiology Trials Network is an investigator-initiated multicenter research collaboration coordinated by the TIMI Study Group (Boston, MA). Consecutive admissions with or at-risk for cardiogenic shock during two annual 2-month collection periods (2017-2019) were analyzed. PATIENTS: Patients with or at-risk for cardiogenic shock. MEASUREMENTS AND MAIN RESULTS: Of 8,240 CICU admissions reviewed, 1,991 (24%) had or were at-risk for cardiogenic shock. Distributions across the five stages were as follows: A: 33%; B: 7%; C: 16%; D: 23%; and E: 21%. Overall in-hospital mortality among patients with established cardiogenic shock was 39%; however, mortality varied from only 15.8% to 32.1% to 62.5% across stages C, D, and E (Cochran-Armitage ptrend < 0.0001). The Society for Cardiovascular Angiography and Interventions stages improved mortality prediction beyond the Sequential Organ Failure Assessment and Intra-Aortic Balloon Pumpin Cardiogenic Shock II scores. CONCLUSIONS: Although overall mortality in cardiogenic shock remains high, it varies considerably based on clinical stage, identifying stage C as relatively lower risk. We demonstrate a pragmatic adaptation of the Society for Cardiovascular Angiography and Interventions cardiogenic shock stages that effectively stratifies mortality risk and could be leveraged for future clinical research.

Rate Versus Rhythm Control in Heart Failure Patients with Post-Operative Atrial Fibrillation After Cardiac Surgery.

BACKGROUND: Whether rhythm control for post-operative atrial fibrillation after cardiac surgery (POAF) is superior to rate control in patients with heart failure or systolic dysfunction (HF) is not known. METHODS: We performed a post-hoc analysis of a trial by the Cardiothoracic Surgical Trials Network, which randomized patients with POAF after cardiac surgery to rate control or rhythm control with amiodarone/cardioversion. We assessed subgroups of trial participants defined by heart failure/cardiomyopathy history or left ventricular ejection fraction (LVEF) < 50%. We conducted a stratified analysis in patients with and without HF to explore outcomes of rhythm versus rate control strategy. RESULTS: Of 523 subjects with POAF after cardiac surgery, 131 (25%) had HF. 49% of HF patients were randomized to rhythm control. In HF patients, rhythm control was associated with less atrial fibrillation within the first 7 days. There were no differences in rhythm at 30- and 60-day follow-up. In the HF group, there were significantly more subjects with AF < 48 hours in the rhythm control group compared to rate control group- 68.8% compared to 46.3%, P=0.009. By comparison, in the non-HF stratum, 54.4% of the rate control group had AF < 48 hours compared to 63.5% of the rhythm control group (P=0.067).), though there was no significant interaction of heart failure with cardiac rhythm at 7 days (Pinteraction 0.16). CONCLUSION: Rhythm control for HF patients with POAF after cardiac surgery increases early restoration of sinus rhythm. Rate and rhythm control are both reasonable for HF patients with AF after cardiac surgery.

Quality of Heart Failure Care in the Intensive Care Unit.

Patients with heart failure (HF) who are seen in an intensive care unit (ICU) manifest the highest-risk, most complex and most resource-intensive disease states. These patients account for a large relative proportion of days spent in an ICU. The paradigms by which critical care is provided to patients with HF are being reconsidered, including consideration of various multidisciplinary ICU staffing models and the development of acute-response teams. Traditional HF quality initiatives have centered on the peri- and postdischarge period in attempts to improve adherence to guideline-directed therapies and reduce readmissions. There is a compelling rationale for expanding high-quality efforts in treating patients with HF who are receiving critical care so we can improve outcomes, reduce preventable harm, improve teamwork and resource use, and achieve high health-system performance. Our goal is to answer the following question: For a patient with HF in the ICU, what is required for the provision of high-quality care? Herein, we first review the epidemiology of HF syndromes in the ICU and identify relevant critical care and quality stakeholders in HF. We next discuss the tenets of high-quality care for patients with HF in the ICU that will optimize critical care outcomes, such as ICU staffing models and evidence-based management of cardiac and noncardiac disease. We discuss strategies to mitigate preventable harm, improve ICU culture and conduct outcomes review, and we conclude with our summative vision of high-quality of ICU care for patients with HF; our vision includes clinical excellence, teamwork and ICU culture.

Association between Respiratory Failure and Clinical Outcomes in Patients with Acute Heart Failure: Analysis of 5 Pooled Clinical Trials.

BACKGROUND: Despite a temporal increase in respiratory failure in patients hospitalized with acute heart failure (HF), clinical trials have largely not reported the incidence or associated clinical outcomes for patients requiring mechanical ventilation. METHODS AND RESULTS: After pooling 5 acute HF clinical trials, we used multivariable logistic regression adjusted for demographics, comorbidities, examinations, and laboratory findings to assess associations between mechanical ventilation and clinical outcomes. Among the 8296 patients, 210 (2.5%) required mechanical ventilation. Age, sex, smoking history, baseline ejection fraction, HF etiology, and the proportion of patients randomized to treatment or placebo in the original clinical trial were similar between groups (all, P > 0.05). Baseline diabetes mellitus was more common in the mechanical ventilation group (P = 0.02), but other comorbidities, including chronic lung disease, were otherwise similar (all P > 0.05). HF rehospitalization at 30 days (12.7% vs 6.6%, P < 0.001) and all-cause 60-day mortality (33.3% vs 6.1%, P < 0.001) was higher among patients requiring mechanical ventilation. After multivariable adjustment, mechanical ventilation use was associated with an increased 30-day HF rehospitalization (odds ratio 2.03; 95% confidence interval, 1.29-3.21, P = 0.002), 30-day mortality (odds ratio 10.40; 95% confidence interval, 7.22-14.98, P < 0.001), and 60-day mortality (odds ratio 7.68; 95% confidence interval, 5.50-10.74, P < 0.001). The influence of mechanical ventilation did not differ by HF etiology or baseline ejection fraction (both, interaction P > 0.20). CONCLUSIONS: Respiratory failure during an index hospitalization for acute HF was associated with increased rehospitalization and all-cause mortality. The development of respiratory failure during an acute HF admission identifies a particularly vulnerable population, which should be identified for closer monitoring.

De Novo vs Acute-on-Chronic Presentations of Heart Failure-Related Cardiogenic Shock: Insights from the Critical Care Cardiology Trials Network Registry.

BACKGROUND: Heart failure-related cardiogenic shock (HF-CS) accounts for an increasing proportion of cases of CS in contemporary cardiac intensive care units. Whether the chronicity of HF identifies distinct clinical profiles of HF-CS is unknown. METHODS AND RESULTS: We evaluated admissions to cardiac intensive care units for HF-CS in 28 centers using data from the Critical Care Cardiology Trials Network registry (2017-2020). HF-CS was defined as CS due to ventricular failure in the absence of acute myocardial infarction and was classified as de novo vs acute-on-chronic based on the absence or presence of a prior diagnosis of HF, respectively. Clinical features, resource use, and outcomes were compared among groups. Of 1405 admissions with HF-CS, 370 had de novo HF-CS (26.3%), and 1035 had acute-on-chronic HF-CS (73.7%). Patients with de novo HF-CS had a lower prevalence of hypertension, diabetes, coronary artery disease, atrial fibrillation, and chronic kidney disease (all P < 0.01). Median Sequential Organ Failure Assessment (SOFA) scores were higher in those with de novo HF-CS (8; 25th-75th: 5-11) vs acute-on-chronic HF-CS (6; 25th-75th: 4-9, P < 0.01), as was the proportion of Society of Cardiovascular Angiography and Intervention (SCAI) shock stage E (46.1% vs 26.1%, P < 0.01). After adjustment for clinical covariates and preceding cardiac arrest, the risk of in-hospital mortality was higher in patients with de novo HF-CS than in those with acute-on-chronic HF-CS (adjusted hazard ratio 1.36, 95% confidence interval 1.05-1.75, P = 0.02). CONCLUSIONS: Despite having fewer comorbidities, patients with de novo HF-CS had more severe shock presentations and worse in-hospital outcomes. Whether HF disease chronicity is associated with time-dependent compensatory adaptations, unique pathobiological features and responses to treatment in patients presenting with HF-CS warrants further investigation.

Predictors of operative mortality among cardiac surgery patients with prolonged ventilation.

BACKGROUND: Prolonged ventilation after cardiac surgery affects survival and increases morbidity. Previous studies have focused on predicting this complication preoperatively; however, indicators of poor outcome in those requiring prolonged ventilation remain ill-defined. We sought to identify predictors of operative mortality in cardiac surgery patients who experience prolonged mechanical ventilation. METHODS: 1698 patients who underwent cardiac surgery (CAB, aortic valve replacement ± CAB, or mitral valve repair/replacement ± CAB) required prolonged postoperative mechanical ventilation (>24 hours) between 2012 to 2016 in a statewide consortium. Perioperative factors were evaluated to identify the association with operative mortality. Covariates were selected through bootstrap aggregation to fit multivariable logistic regression models. The relative strength of association was determined by the Wald chi-square statistic. RESULTS: Median patient age was 68 years [IQR 61 to 76], 38% (644/1,698) were female, median duration of mechanical ventilation was 65 hours [IQR 38 to 143], median STS predicted risk of mortality was 3.1% [IQR 1.4 to 6.9%], and 15.7% (266/1698) suffered operative mortality. Among preoperative and operative characteristics, patient age and intraoperative initiation of extracorporeal membrane oxygenation (ECMO) were the strongest correlates of operative mortality on the multivariate analysis. Among postoperative factors, cardiac arrest and renal failure requiring dialysis were the strongest predictors of risk-adjusted operative mortality. Type of operation or surgical center had no association to mortality after risk adjustment. CONCLUSION: Prolonged ventilation following cardiac surgery is associated with a five-fold increase in operative mortality. In these patients, operative mortality is associated with older age, intraoperative initiation of ECMO, postoperative cardiac arrest, and renal failure requiring dialysis.

Prevalence and Prognostic Association of Circulating Troponin in the Acute Respiratory Distress Syndrome.

OBJECTIVE: Circulating cardiac troponin has been associated with adverse prognosis in the acute respiratory distress syndrome in small and single-center studies; however, comprehensive studies of myocardial injury in acute respiratory distress syndrome using modern high-sensitivity troponin assays, which can detect troponin at much lower circulating concentrations, have not been performed. DESIGN: We performed a prospective cohort study. SETTING: We included patients enrolled in previously completed trials of acute respiratory distress syndrome. PATIENTS: One thousand fifty-seven acute respiratory distress syndrome patients were included. INTERVENTIONS: To determine the association of circulating high-sensitivity troponin I (Abbott ARCHITECT), with acute respiratory distress syndrome outcomes, we measured high-sensitivity troponin I within 24 hours of intubation. The primary outcome was 60-day mortality. MEASUREMENTS AND MAIN RESULTS: Detectable high-sensitivity troponin I was present in 94% of patients; 38% of patients had detectable levels below the 99th percentile of a healthy reference population (26 ng/L), whereas 56% of patients had levels above the 99th percentile cut point. After multivariable adjustment, age, cause of acute respiratory distress syndrome, temperature, heart rate, vasopressor use, Sequential Organ Failure Assessment score, creatinine, and PCO2 were associated with higher high-sensitivity troponin I concentration. After adjustment for age, sex, and randomized trial assignment, the hazard ratio for 60-day mortality comparing the fifth to the first quintiles of high-sensitivity troponin I was 1.61 (95% CI, 1.11-2.32; p trend = 0.003). Adjusting for Sequential Organ Failure Assessment score suggested that this association was not independent of disease severity (hazard ratio, 0.95; 95% CI, 0.64-1.39; p = 0.93). CONCLUSIONS: Circulating troponin is detectable in over 90% of patients with acute respiratory distress syndrome and is associated with degree of critical illness. The magnitude of myocardial injury correlated with mortality.

Pulmonary Arterial Compliance in Acute Respiratory Distress Syndrome: Clinical Determinants and Association With Outcome From the Fluid and Catheter Treatment Trial Cohort.

OBJECTIVES: Pulmonary vascular dysfunction is associated with adverse prognosis in patients with the acute respiratory distress syndrome; however, the prognostic impact of pulmonary arterial compliance in acute respiratory distress syndrome is not established. DESIGN, SETTING, PATIENTS: We performed a retrospective analysis of 363 subjects with acute respiratory distress syndrome who had complete baseline right heart catheterization data from the Fluid and Catheter Treatment Trial to test whether pulmonary arterial compliance at baseline and over the course of treatment predicted mortality. MAIN RESULTS: Baseline pulmonary arterial compliance (hazard ratio, 1.18 per interquartile range of 1/pulmonary arterial compliance; 95% CI, 1.02-1.37; p = 0.03) and pulmonary vascular resistance (hazard ratio, 1.28 per interquartile range; 95% CI, 1.07-1.53; p = 0.006) both modestly predicted 60-day mortality. Baseline pulmonary arterial compliance remained predictive of mortality when pulmonary vascular resistance was in the normal range (p = 0.02). Between day 0 and day 3, pulmonary arterial compliance increased in acute respiratory distress syndrome survivors and remained unchanged in nonsurvivors, whereas pulmonary vascular resistance did not change in either group. The resistance-compliance product (resistance-compliance time) increased in survivors compared with nonsurvivors, suggesting improvements in right ventricular load. CONCLUSIONS: Baseline measures of pulmonary arterial compliance and pulmonary vascular resistance predict mortality in acute respiratory distress syndrome, and pulmonary arterial compliance remains predictive even when pulmonary vascular resistance is normal. Pulmonary arterial compliance and right ventricular load improve over time in acute respiratory distress syndrome survivors. Future studies should assess the impact of right ventricular protective acute respiratory distress syndrome treatment on right ventricular afterload and outcome.

Dynamic Changes in High-Sensitivity Cardiac Troponin I Are Associated with Dynamic Changes in Sum Absolute QRST Integral on Surface Electrocardiogram in Acute Decompensated Heart Failure.

BACKGROUND: A three-dimensional electrocardiographic (ECG) metric, the sum absolute QRST integral (SAI QRST), predicts ventricular arrhythmias in heart failure (HF) patients with implantable cardioverter defibrillator and mechanical response to cardiac resynchronization therapy. We hypothesized that there is an association between patient-specific changes in SAI QRST and myocardial injury as measured by high-sensitivity troponin I (hsTnI). METHODS: Sum absolute integral QRST on resting 12-lead ECG and hsTnI were measured simultaneously, every 3 hours, and during 12-hour observation period in a prospective cohort of emergency department patients (n = 398; mean age 57.8 ± 13.2 years; 54% female, 64% black), diagnosed with acute coronary syndrome (ACS, n = 28), acutely decompensated HF (acute decompensated heart failure, n = 35), cardiac non-ACS (n = 19), or noncardiac condition (n = 316). Random-effects linear regression analysis assessed the association of SAI QRST and myocardial injury, with adjustment for demographics (age, sex, race), prevalent cardiovascular disease (myocardial infarction, history of revascularization, stroke, and HF), risk factors (diabetes, smoking, hypercholesterolemia, hypertension, and cocaine use), and left bundle branch block. RESULTS: Within the entire cohort, SAI QRST decreased by 3 (95%CI -5 to -1) mV*ms every 3 hours. A 10-fold increase in hsTnI was associated with a 7.7 (0.6-14.9) mV*ms increase in SAI QRST. In the subgroup of acutely decompensated HF patients (n = 35), a 10-fold increase in hsTnI was associated with a 61.0 (5.9-116.1) mV*ms increase in SAI QRST. CONCLUSION: Patient-specific time-varying changes in the surface ECG scalar measure of global electrical heterogeneity, as measured by SAI QRST, and in myocardial injury as measured by hsTnI, are independently and directly associated with each other, likely reflecting a common underlying mechanism.

Association of High-Sensitivity Cardiac Troponin I Concentration With Cardiac Outcomes in Patients With Suspected Acute Coronary Syndrome.

Importance: High-sensitivity cardiac troponin I testing is widely used to evaluate patients with suspected acute coronary syndrome. A cardiac troponin concentration of less than 5 ng/L identifies patients at presentation as low risk, but the optimal threshold is uncertain. Objective: To evaluate the performance of a cardiac troponin I threshold of 5 ng/L at presentation as a risk stratification tool in patients with suspected acute coronary syndrome. Data Sources: Systematic search of MEDLINE, EMBASE, Cochrane, and Web of Science databases from January 1, 2006, to March 18, 2017. Study Selection: Prospective studies measuring high-sensitivity cardiac troponin I concentrations in patients with suspected acute coronary syndrome in which the diagnosis was adjudicated according to the universal definition of myocardial infarction. Data Extraction and Synthesis: The systematic review identified 19 cohorts. Individual patient-level data were obtained from the corresponding authors of 17 cohorts, with aggregate data from 2 cohorts. Meta-estimates for primary and secondary outcomes were derived using a binomial-normal random-effects model. Main Outcomes and Measures: The primary outcome was myocardial infarction or cardiac death at 30 days. Performance was evaluated in subgroups and across a range of troponin concentrations (2-16 ng/L) using individual patient data. Results: Of 11 845 articles identified, 104 underwent full-text review, and 19 cohorts from 9 countries were included. Among 22 457 patients included in the meta-analysis (mean age, 62 [SD, 15.5] years; n = 9329 women [41.5%]), the primary outcome occurred in 2786 (12.4%). Cardiac troponin I concentrations were less than 5 ng/L at presentation in 11 012 patients (49%), in whom there were 60 missed index or 30-day events (59 index myocardial infarctions, 1 myocardial infarction at 30 days, and no cardiac deaths at 30 days). This resulted in a negative predictive value of 99.5% (95% CI, 99.3%-99.6%) for the primary outcome. There were no cardiac deaths at 30 days and 7 (0.1%) at 1 year, with a negative predictive value of 99.9% (95% CI, 99.7%-99.9%) for cardiac death. Conclusions and Relevance: Among patients with suspected acute coronary syndrome, a high-sensitivity cardiac troponin I concentration of less than 5 ng/L identified those at low risk of myocardial infarction or cardiac death within 30 days. Further research is needed to understand the clinical utility and cost-effectiveness of this approach to risk stratification.