Pulmonary vascular structure and function are related to exercise capacity in health and COPD.

BACKGROUND: Although it is generally accepted that aerobic exercise training does not change lung structure or function, some work suggests that greater pulmonary vascular structure and function is associated with higher exercise capacity (VO2peak). RESEARCH QUESTION: Is there a cross-sectional association between the pulmonary vasculature and VO2peak? We hypothesized that those with higher computed tomography (CT) blood vessel volumes, and pulmonary diffusing capacity for carbon monoxide (DLCO) would have higher VO2peak, independent of airflow limitation. STUDY DESIGN AND METHODS: Participants from the CanCOLD study were categorized as: never-smokers with normal spirometry (n=263); ever-smokers with normal spirometry (n=407); and chronic obstructive pulmonary disease (COPD): individuals with spirometric airflow obstruction (n=334). Total vessel volume (TVV), the volume for all vessels with a cross-sectional area ≤5 mm2 (BV5), and between 5-10 mm2 (BV5-10) were generated from CT scans and used as indices of pulmonary vascular structure. DLCO was used as an index of pulmonary microvascular function. VO2peak was evaluated via incremental cardiopulmonary exercise testing. RESULTS: General linear regression models revealed that even after controlling for FEV1, emphysema severity and body morphology, DLCO, TVV, BV5 and BV5-10, were independently associated with VO2peak. Interaction effects were observed between COPD and TVV, BV5, and BV5-10 indicating a weaker association between pulmonary vascular volumes and VO2peak in COPD. INTERPRETATION: Our results suggest that pulmonary vascular structure and DLCO is independently associated with VO2peak, regardless of severity of airflow limitation and emphysema, suggesting that these associations are not limited to COPD.

Epidemiology of Cardiogenic Shock Using the Shock Academic Research Consortium (SHARC) Consensus Definitions.

BACKGROUND: The Shock Academic Research Consortium (SHARC) recently proposed pragmatic consensus definitions to standardize classification of cardiogenic shock (CS) in registries and clinical trials. We aimed to describe contemporary CS epidemiology using the SHARC definitions in a cardiac intensive care unit (CICU) population. METHODS: The Critical Care Cardiology Trials Network (CCCTN) is a multinational research network of advanced CICUs coordinated by the TIMI Study Group (Boston, MA). CS was defined as a cardiac disorder resulting in SBP<90mmHg for ≥30 minutes (or the need for vasopressors, inotropes, or mechanical circulatory support [MCS] to maintain SBP ≥90mmHg) with evidence of hypoperfusion. Primary etiologic categories included acute myocardial infarction-related CS (AMI-CS), heart failure-related CS (HF-CS), and non-myocardial (secondary) CS. Post-cardiotomy CS was not included. HF-CS was further subcategorized as de novo vs. acute-on-chronic HF-CS. Patients with both cardiogenic and non-cardiogenic components of shock were classified separately as mixed CS. RESULTS: Of 8,974 patients meeting shock criteria (2017-2023), 65% had isolated CS and 17% had mixed shock. Among patients with CS (n=5,869), 27% had AMI-CS (65% STEMI), 59% HF-CS (72% acute-on-chronic, 28% de novo), and 14% secondary CS. Patients with AMI-CS and de novo HF-CS were most likely to have had concomitant cardiac arrest (p<0.001). Patients with AMI-CS and mixed CS were most likely to present in more severe shock stages (SCAI D or E; p<0.001). Temporary MCS use was highest in AMI-CS (59%). In-hospital mortality was highest in mixed CS (48%), followed by AMI-CS (41%), similar in de novo HF-CS (31%) and secondary CS (31%), and lowest in acute-on-chronic HF-CS (25%; p<0.001). CONCLUSIONS: SHARC consensus definitions for CS classification can be pragmatically applied in contemporary registries and reveal discrete subpopulations of CS with distinct phenotypes and outcomes that may be relevant to clinical practice and future research.

Continuum of Preshock to Classic Cardiogenic Shock in the Critical Care Cardiology Trials Network Registry.

BACKGROUND: The prognostic implications of phenotypes along the preshock to cardiogenic shock (CS) continuum remain uncertain. OBJECTIVES: This study sought to better characterize pre- or early shock and normotensive CS phenotypes and examine outcomes compared to those with conventional CS. METHODS: The CCCTN (Critical Care Cardiology Trials Network) is a registry of contemporary cardiac intensive care units. Consecutive admissions (N = 28,703 across 47 sites) meeting specific criteria based on hemodynamic variables, perfusion parameters, and investigator-reported CS were classified into 1 of 4 groups or none: isolated low cardiac output (CO), heart failure with isolated hypotension, normotensive CS, or SCAI (Society of Cardiovascular Angiography and Intervention) stage C CS. Outcomes of interest were in-hospital mortality and incidence of subsequent hypoperfusion among pre- and early shock states. RESULTS: A total of 2,498 admissions were assigned to the 4 groups with the following distribution: 4.8% isolated low CO, 4.4% isolated hypotension, 12.1% normotensive CS, and 78.7% SCAI stage C CS. Overall in-hospital mortality was 21.3% (95% CI: 19.7%-23.0%), with a gradient across phenotypes (isolated low CO 3.6% [95% CI: 1.0%-9.0%]; isolated hypotension 11.0% [95% CI: 6.9%-16.6%]; normotensive CS 17.0% [95% CI 13.0%-21.8%]; SCAI stage C CS 24.0% [95% CI: 22.1%-26.0%]; global P < 0.001). Among those with an isolated low CO and isolated hypotension on admission, 47 (42.3%) and 56 (30.9%) subsequently developed hypoperfusion. CONCLUSIONS: In a large contemporary registry of cardiac critical illness, there exists a gradient of mortality for phenotypes along the preshock to CS continuum with risk for subsequent worsening of preshock states. These data may inform refinement of CS definitions and severity staging.

Characteristics and Outcomes of Adults With Congenital Heart Disease in the Cardiac Intensive Care Unit.

Background: Little is known regarding the characteristics, treatment patterns, and outcomes in patients with adult congenital heart disease (ACHD) admitted to cardiac intensive care units (CICUs). Objectives: The authors sought to better define the contemporary epidemiology, treatment patterns, and outcomes of ACHD admissions in the CICU. Methods: The Critical Care Cardiology Trials Network is a multicenter network of CICUs in North America. Participating centers contributed prospective data from consecutive admissions during 2-month annual snapshots from 2017 to 2022. We analyzed characteristics and outcomes of admissions with ACHD compared with those without ACHD. Multivariable logistic regression was used to assess mortality in ACHD vs non-ACHD admissions. Results: Of 23,299 CICU admissions across 42 sites, there were 441 (1.9%) ACHD admissions. Shunt lesions were most common (46.1%), followed by right-sided lesions (29.5%) and complex lesions (28.7%). ACHD admissions were younger (median age 46 vs 67 years) than non-ACHD admissions. ACHD admissions were more commonly for heart failure (21.3% vs 15.7%, P < 0.001), general medical problems (15.6% vs 6.0%, P < 0.001), and atrial arrhythmias (8.6% vs 4.9%, P < 0.001). ACHD admissions had a higher median presenting Sequential Organ Failure Assessment score (5.0 vs 3.0, P < 0.001). Total hospital stay was longer for ACHD admissions (8.2 vs 5.9 days, P < 0.01), though in-hospital mortality was not different (12.7% vs 13.6%; age- and sex-adjusted OR: 1.19 [95% CI: 0.89-1.59], P = 0.239). Conclusions: This study illustrates the unique aspects of the ACHD CICU admission. Further investigation into the best approach to manage specific ACHD-related CICU admissions, such as cardiogenic shock and acute respiratory failure, is warranted.

Current practices in the management of temporary mechanical circulatory support: A survey of CICU directors in North America.

INTRODUCTION: Despite the growing use of temporary mechanical circulatory support (tMCS), little data exists to inform management and weaning of these devices. METHODS: We performed an online survey among cardiac intensive care unit directors in North America to examine current practices in the management of patients treated with intraaortic balloon pump and Impella. RESULTS: We received responses from 84% of surveyed centers (n=37). Our survey focused on three key aspects of daily management: 1. Hemodynamic monitoring; 2. Hemocompatibility; and 3. Weaning and removal. We found substantial variability surrounding all three areas of care. CONCLUSION: Our findings highlight the need for consensus around practices associated with improved outcomes in patients treated with tMCS.

Arterial hyperoxia and mortality in the cardiac intensive care unit.

BACKGROUND: Arterial hyperoxia (hyperoxemia), defined as a high arterial partial pressure of oxygen (PaO2), has been associated with adverse outcomes in critically ill populations, but has not been examined in the cardiac intensive care unit (CICU). We evaluated the association between exposure to hyperoxia on admission with in-hospital mortality in a mixed CICU cohort. METHODS: We included unique Mayo Clinic CICU patients admitted from 2007 to 2018 with admission PaO2 data (defined as the PaO2 value closest to CICU admission) and no hypoxia (PaO2 < 60mmHg). The admission PaO2 was evaluated as a continuous variable and categorized (60-100 mmHg, 101-150 mmHg, 151-200 mmHg, 201-300 mmHg, >300 mmHg). Logistic regression was used to evaluate predictors of in-hospital mortality before and after multivariable adjustment. RESULTS: We included 3,368 patients with a median age of 70.3 years; 70.3% received positive-pressure ventilation. The median PaO2 was 99 mmHg, with a distribution as follows: 60-100 mmHg, 51.9%; 101-150 mmHg, 28.6%; 151-200 mmHg, 10.6%; 201-300 mmHg, 6.4%; >300 mmHg, 2.5%. A J-shaped association between admission PaO2 and in-hospital mortality was observed, with a nadir around 100 mmHg. A higher PaO2 was associated with increased in-hospital mortality (adjusted OR 1.17 per 100 mmHg higher, 95% CI 1.01-1.34, p = 0.03). Patients with PaO2 >300 mmHg had higher in-hospital mortality versus PaO2 60-100 mmHg (adjusted OR 2.37, 95% CI 1.41-3.94, p < 0.001). CONCLUSIONS: Hyperoxia at the time of CICU admission is associated with higher in-hospital mortality, primarily in those with severely elevated PaO2 >300 mmHg.

Resource Utilization and Costs Associated With Cardiogenic Shock Complicating Myocardial Infarction: A Population-Based Cohort Study.

Background: Cardiogenic shock due to acute myocardial infarction (AMI-CS) is associated with significant short- and long-term morbidity and mortality. Despite this, little is known about associated cost. Objectives: The purpose of this study was to evaluate the health care costs and resource use associated with AMI-CS using administrative data from the province of Ontario, Canada. Methods: This was a retrospective cohort study of adult patients with AMI-CS from April 2009 to March 2019. One-year costs following index admission were reported at an individual level. We used generalized linear models to identify factors associated with increased cost. We stratified patients by revascularization strategy to compare cost in each group and examined total cost at a patient level per individual fiscal year. Results: We included 9,789 consecutive patients with AMI-CS across 135 centers in Ontario (mean age 70.5 years; 67.7% male). Mortality in-hospital was 30.2%, and mortality at 2 years was 45.9%. The median inpatient cost per patient was $23,912 (IQR: $12,234-$41,833) with a median total 1-year cost of $37,913 (IQR: $20,113-$66,582). The median 1-year cost was $17,730 (IQR: $9,323-$38,379) for those who died in hospital, and $45,713 (IQR: $29,688-$77,683) for those surviving to discharge, with $12,719 (IQR: $4,262-$35,275) occurring after discharge. Patients who received coronary artery bypass grafting incurred the highest cost among revascularization groups. No significant differences were observed in cost per fiscal year from 2009 to 2019. Conclusions: AMI-CS is associated with significant health care costs, both during the index hospitalization and following discharge. To optimize cost-effectiveness, future therapies should aim to reduce disability in addition to improving mortality.

Premature Acute Myocardial Infarction Treated With Invasive Revascularization: Comparing STEMI With NSTEMI in a Population-Based Study of Young Patients.

BACKGROUND: Acute myocardial infarction (AMI) usually presents in older populations, in which there are established demographic and outcome differences for ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). No similar comparisons for AMI in the young population exist. METHODS: We compared all index NSTEMI and STEMI hospitalizations in young (18-45 years) patients who required revascularization in Alberta, Canada. Outcomes were survival to discharge, and a composite of heart failure hospitalization, cardiac arrest hospitalization, and all-cause mortality at 1 and 5 years. RESULTS: There were 1679 patients included with an index AMI who required revascularization: 655 (39.0%) NSTEMI and 1024 (61.0%) STEMI. The population was disproportionately male (86%), particularly in STEMI patients (87.3%). Marked dyslipidemia (35%) and active smoking (42%) were common, with similar rates among groups. Percutaneous coronary intervention was used in 98.7% of STEMI and 91.5% of NSTEMI patients (P < 0.001), with the remainder who underwent surgical revascularization. The in-hospital mortality rate during index AMI was higher in STEMI compared with NSTEMI patients (1.7% vs 0%; P < 0.001). The rates of the composite outcome were similar for both groups at 1 and 5 years of follow-up in patients who survived to index hospital discharge. After adjusting for sex, age, heart failure and/or cardiac arrest at index AMI, outcomes remained similar among groups at 1 and 5 years. CONCLUSIONS: In young patients with AMI, STEMI was a disproportionately male phenomenon and associated with higher mortality at index hospitalization. One-year and 5-year outcomes were similar among STEMI and NSTEMI patients in those discharged alive at index AMI. Smoking and dyslipidemia appear to be major risk factors in the young.

The Impact of an Accelerated Diagnostic Protocol Using Conventional Troponin I for Patients With Cardiac Chest Pain in the Emergency Department.

Background: This study strove to assess the impact of the implementation of an accelerated diagnostic protocol (ADP), using shortened serial-testing intervals and a conventional troponin I (c-TnI) test, on emergency department (ED) length of stay (LOS). Methods: This retrospective cohort study included adults (aged ≥ 18 years) presenting to a Canadian ED with a primary complaint of cardiac chest pain between January 14, 2017 and January 15, 2019. For non-high-risk patients, the troponin delta timing decreased from 6 hours to 3 hours, and a different conventional troponin I level cut-point was implemented on January 15, 2018. The primary outcome was ED LOS. Secondary outcomes included disposition status, consultation proportions, and major adverse cardiac events within 30 days. Results: A total of 3133 patient interactions were included. Although the overall decrease in median ED LOS was not significant (P = 0.074), a significant reduction occurred in ED LOS (-33 minutes; 95% confidence interval: -53.6 to -12.4 minutes) among patients who were discharged in the post-ADP group. Consultations were unchanged between groups (36.1% before vs 33.8% after; P = 0.17). The major adverse cardiac events outcomes were unchanged across cohorts (15.9% vs 15.3%; P = 0.62). Conclusions: The implementation of an ADP, with a conventional troponin I test, for cardiac chest pain in a Canadian ED was not associated with a significant reduction of LOS for all patients; however, a significant reduction occurred for patients who were discharged, and the strategy appears safe.

Contexte: Cette étude visait à évaluer les répercussions de la mise en œuvre d'un protocole de diagnostic accéléré avec intervalles plus courts entre les épreuves séquentielles et dosage classique de la troponine I sur la durée du séjour à l'urgence. Méthodologie: Cette étude de cohortes rétrospective a été menée chez des adultes (âgés de 18 ans ou plus) qui se sont présentés à l'urgence d'un hôpital canadien principalement pour une douleur thoracique cardiaque entre le 14 janvier 2017 et le 15 janvier 2019. Chez les patients qui n'étaient pas exposés à un risque élevé, l'intervalle de dosage de la troponine (delta) est passé de 6 heures à 3 heures, et une nouvelle valeur seuil a été utilisée pour le dosage classique de la troponine I à compter du 15 janvier 2018. Le critère d'évaluation principal était la durée du séjour à l'urgence. Les critères d'évaluation secondaires comprenaient le statut au moment de la sortie, les proportions de consultation et les événements cardiovasculaires indésirables majeurs dans les 30 jours. Résultats: Au total, 3 133 interactions avec des patients ont été incluses. Bien que la diminution globale de la durée médiane du séjour à l'urgence n'ait pas été significative (p = 0,074), une réduction significative du séjour à l'urgence (-33 minutes; intervalle de confiance à 95 % : -53,6 à -12,4 minutes) a été observée chez les patients ayant reçu leur congé appartenant au groupe dans lequel le protocole de diagnostic accéléré a été mis en œuvre. Les consultations étaient inchangées entre les groupes (36,1 % avant vs 33,8 % après; p = 0,17). Les résultats relatifs aux événements cardiovasculaires indésirables majeurs sont demeurés inchangés dans les cohortes (15,9 % vs 15,3 %; p = 0,62). Conclusions: La mise en œuvre d'un protocole de diagnostic accéléré, avec un dosage classique de la troponine I, en cas de douleur thoracique d'origine cardiaque, à l'urgence d'un établissement canadien ne s'est pas traduite par une réduction significative du séjour à l'urgence chez tous les patients. Une réduction significative a néanmoins été observée chez les patients qui ont reçu leur congé, et la stratégie s'est avérée sûre.

Admission Total Leukocyte Count as a Predictor of Mortality in Cardiac Intensive Care Unit Patients.

Background: Inflammation is a sequela of cardiovascular critical illness and a risk factor for mortality. Objectives: This study aimed to evaluate the association between white blood cell count (WBC) and mortality in a broad population of patients admitted to the cardiac intensive care unit (CICU). Methods: This retrospective cohort study included patients admitted to the Mayo Clinic CICU between 2007 and 2018. We analyzed WBC as a continuous variable and then categorized WBC as low (<4.0 × 103/mL), normal (≥4.0 to <11.0 × 103/mL), high (≥11.0 to <22.0 × 103/mL), or very high (≥22.0 × 103/mL). The association between WBC and in-hospital mortality was evaluated using multivariable logistic regression and random forest models. Results: We included 11,699 patients with a median age of 69.3 years (37.6% females). Median WBC was 9.6 (IQR: 7.4-12.7). Mortality was higher in the low (10.5%), high (12.0%), and very high (33.3%) WBC groups relative to the normal WBC group (5.3%). A rising WBC was incrementally associated with higher in-hospital mortality after adjustment (AICc adjusted OR: 1.03 [95% CI: 1.02-1.04] per 1 × 103 increase in WBC). After adjustment, only the high (AICc adjusted OR: 1.37 [95% CI: 1.15-1.64]) and very high (AICc adjusted OR: 1.99 [1.47-2.71]) WBC groups remained associated with increased risk of in-hospital mortality. Conclusions: Leukocytosis is associated with an increased mortality risk in a diverse cohort of CICU patients. This readily available marker of systemic inflammation may be useful for risk stratification within the increasingly complex CICU patient population.

Sex Differences in Characteristics, Resource Utilization, and Outcomes of Cardiogenic Shock: Data From the Critical Care Cardiology Trials Network (CCCTN) Registry.

BACKGROUND: Sex disparities exist in the management and outcomes of various cardiovascular diseases. However, little is known about sex differences in cardiogenic shock (CS). We sought to assess sex-related differences in the characteristics, resource utilization, and outcomes of patients with CS. METHODS: The Critical Care Cardiology Trials Network is a multicenter registry of advanced cardiac intensive care units (CICUs) in North America. Between 2018 and 2022, each center (N=35) contributed annual 2-month snapshots of consecutive CICU admissions. Patients with CS were stratified as either CS after acute myocardial infarction or heart failure-related CS (HF-CS). Multivariable logistic regression was used for analyses. RESULTS: Of the 22 869 admissions in the overall population, 4505 (20%) had CS. Among 3923 patients with CS due to ventricular failure (32% female), 1235 (31%) had CS after acute myocardial infarction and 2688 (69%) had HF-CS. Median sequential organ failure assessment scores did not differ by sex. Women with HF-CS had shorter CICU lengths of stay (4.5 versus 5.4 days; P<0.0001) and shorter overall lengths of hospital stay (10.9 versus 12.8 days; P<0.0001) than men. Women with HF-CS were less likely to receive pulmonary artery catheters (50% versus 55%; P<0.01) and mechanical circulatory support (26% versus 34%; P<0.0001) compared with men. Women with HF-CS had higher in-hospital mortality than men, even after adjusting for age, illness severity, and comorbidities (34% versus 23%; odds ratio, 1.76 [95% CI, 1.42-2.17]). In contrast, there were no significant sex differences in utilization of advanced CICU monitoring and interventions, or mortality, among patients with CS after acute myocardial infarction. CONCLUSIONS: Women with HF-CS had lower use of pulmonary artery catheters and mechanical circulatory support, shorter CICU lengths of stay, and higher in-hospital mortality than men, even after accounting for age, illness severity, and comorbidities. These data highlight the need to identify underlying reasons driving the differences in treatment decisions, so outcomes gaps in HF-CS can be understood and eliminated.