Mechanisms of Post-critical Illness Cardiovascular Disease

Characterizing Cardiac Function in ICU Survivors of Sepsis: A Pilot Study Protocol

Background

Sepsis is one of the most common reasons for ICU admission and a leading cause of mortality worldwide. More than one-half of survivors experience significant physical, psychological, or cognitive impairments, often termed post-intensive care syndrome (PICS). Sepsis is recognized increasingly as being associated with a risk of adverse cardiovascular events that is comparable with other major cardiovascular risk factors. It is plausible that sepsis survivors may be at risk of unidentified cardiovascular disease, and this may play a role in functional impairments seen after ICU discharge.

Research Question

What is the prevalence of myocardial dysfunction after an ICU admission with sepsis and to what extent might it be associated with physical impairments in PICS?

Study Design and Methods

Characterisation of Cardiovascular Function in ICU Survivors of Sepsis (CONDUCT-ICU) is a prospective, multicenter, pilot study characterizing cardiovascular function and functional impairments in survivors of sepsis taking place in the west of Scotland. Survivors of sepsis will be recruited at ICU discharge and followed up 6 to 10 weeks after hospital discharge. Biomarkers of myocardial injury or dysfunction (high sensitivity troponin and N-terminal pro B-type natriuretic peptide) and systemic inflammation (C-reactive protein, IL-1β, IL-6, IL-10, and tumor necrosis factor alpha) will be measured in 69 patients at recruitment and at follow-up. In addition, a cardiovascular magnetic resonance substudy will be performed at follow-up in 35 patients. We will explore associations between cardiovascular magenetic resonance indexes of cardiac function, biomarkers of cardiac dysfunction and inflammation, and patient-reported outcome measures.

Interpretation

CONDUCT-ICU will provide data regarding the cause and prevalence of cardiac dysfunction in survivors of sepsis and will explore associations with functional impairment. It will provide feasibility data and operational learning for larger studies investigating mechanisms of functional impairment after ICU admission and the association between sepsis and adverse cardiovascular events.

Trial Registry

ClinicalTrials.gov; No.: NCT05633290; URL: www.clinicaltrials.gov.

Do critical illness survivors with multimorbidity need a different model of care?

There is currently a lack of evidence on the optimal strategy to support patient recovery after critical illness. Previous research has largely focussed on rehabilitation interventions which aimed to address physical, psychological, and cognitive functional sequelae, the majority of which have failed to demonstrate benefit for the selected outcomes in clinical trials. It is increasingly recognised that a person's existing health status, and in particular multimorbidity (usually defined as two or more medical conditions) and frailty, are strongly associated with their long-term outcomes after critical illness. Recent evidence indicates the existence of a distinct subgroup of critical illness survivors with multimorbidity and high healthcare utilisation, whose prior health trajectory is a better predictor of long-term outcomes than the severity of their acute illness. This review examines the complex relationships between multimorbidity and patient outcomes after critical illness, which are likely mediated by a range of factors including the number, severity, and modifiability of a person's medical conditions, as well as related factors including treatment burden, functional status, healthcare delivery, and social support. We explore potential strategies to optimise patient recovery after critical illness in the presence of multimorbidity. A comprehensive and individualized approach is likely necessary including close coordination among healthcare providers, medication reconciliation and management, and addressing the physical, psychological, and social aspects of recovery. Providing patient-centred care that proactively identifies critical illness survivors with multimorbidity and accounts for their unique challenges and needs is likely crucial to facilitate recovery and improve outcomes.

Cardiac dysfunction in survivors of sepsis: a scoping review

BACKGROUND

Sepsis is associated with an increased risk of adverse cardiovascular events in a magnitude comparable to other major cardiovascular risk factors. Sepsis is one of the most common reasons for intensive care admission and survivors often have significant functional limitations following discharge. However, it is not clear to what extent chronic cardiovascular dysfunction might mediate these functional impairments, or how we might screen and manage these patients at risk of chronic cardiovascular disease. We conducted a scoping review to map existing evidence and identify research gaps relating to cardiovascular dysfunction following sepsis.

METHODS

We conducted a systematic search of MEDLINE, Embase and CINAHL databases using a concept, context, population (CoCoPop) framework. Studies examining cardiovascular outcomes or symptoms following an episode of sepsis in adults were included. Data were mapped based on the population assessed, cardiovascular outcomes examined, inclusion of objective measures of cardiac dysfunction such as biomarkers or cardiovascular imaging, or whether cardiovascular symptoms or patient-reported functional outcomes measures were recorded.

RESULTS

We identified 11 210 articles of which 70 were eligible for full text review and 28 were included in final analysis. Across our dataset, a wide range of incident cardiovascular outcomes were reported in the literature including incidence of congestive heart failure (13/28), arrhythmia (6/28), myocardial infarction (24/28) or cardiovascular death or all-cause mortality (20/28). Only 39% (11/28) of articles reported objective measures of cardiovascular function and only one article related cardiovascular function to functional impairment via patient-reported outcome measures.

CONCLUSION

There are significant gaps in our understanding of cardiac dysfunction following sepsis . While the research highlights the strong association of sepsis with a variety of adverse cardiovascular outcomes, further prospective work is required to understand the mechanisms that mediate this phenomenon and how we can best identify and manage patients at risk.

The vascular perspective on acute and chronic lung disease

The pulmonary vasculature has been frequently overlooked in acute and chronic lung diseases, such as acute respiratory distress syndrome (ARDS), pulmonary fibrosis (PF), and chronic obstructive pulmonary disease (COPD). The primary emphasis in the management of these parenchymal disorders has largely revolved around the injury and aberrant repair of epithelial cells. However, there is increasing evidence that the vascular endothelium plays an active role in the development of acute and chronic lung diseases. The endothelial cell network in the capillary bed and the arterial and venous vessels provides a metabolically highly active barrier that controls the migration of immune cells, regulates vascular tone and permeability, and participates in the remodeling processes. Phenotypically and functionally altered endothelial cells, and remodeled vessels, can be found in acute and chronic lung diseases, although to different degrees, likely because of disease-specific mechanisms. Since vascular remodeling is associated with pulmonary hypertension, which worsens patient outcomes and survival, it is crucial to understand the underlying vascular alterations. In this Review, we describe the current knowledge regarding the role of the pulmonary vasculature in the development and progression of ARDS, PF, and COPD; we also outline future research directions with the hope of facilitating the development of mechanism-based therapies.

Cardiovascular Magnetic Resonance in Survivors of Critical Illness: Cardiac Abnormalities Are Associated With Acute Kidney Injury

Background The objective of this study was to investigate cardiac abnormalities in intensive care unit (ICU) survivors of critical illness and to determine whether temporary acute kidney injury (AKI) is associated with more pronounced findings on cardiovascular magnetic resonance. Methods and Results There were 2175 patients treated in the ICU (from 2015 until 2021) due to critical illness who were screened for study eligibility. Post-ICU patients without known cardiac disease were prospectively recruited from March 2021 to May 2022. Participants underwent cardiovascular magnetic resonance including assessment of cardiac function, myocardial edema, late gadolinium enhancement, and mapping including extracellular volume fraction. Student t test, Mann-Whitney U test, and χ2 tests were used. There were 48 ICU survivors (46±15 years of age, 28 men, 29 with AKI and continuous kidney replacement therapy, and 19 without AKI) and 20 healthy controls who were included. ICU survivors had elevated markers of myocardial fibrosis (T1: 995±31 ms versus 957±21 ms, P<0.001; extracellular volume fraction: 24.9±2.5% versus 22.8±1.2%, P<0.001; late gadolinium enhancement: 1% [0%-3%] versus 0% [0%-0%], P<0.001), more frequent focal late gadolinium enhancement lesions (21% versus 0%, P=0.03), and an impaired left ventricular function (eg, ejection fraction: 57±6% versus 60±5%, P=0.03; systolic longitudinal strain: 20.3±3.7% versus 23.1±3.5%, P=0.004) compared with healthy controls. ICU survivors with AKI had higher myocardial T1 (1002±33 ms versus 983±21 ms; P=0.046) and extracellular volume fraction values (25.6±2.6% versus 23.9±1.9%; P=0.02) compared with participants without AKI. Conclusions ICU survivors of critical illness without previously diagnosed cardiac disease had distinct abnormalities on cardiovascular magnetic resonance including signs of myocardial fibrosis and systolic dysfunction. Findings were more abnormal in participants who experienced AKI with necessity of continuous kidney replacement therapy during their ICU stay. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT05034588.

Oncostatin M Receptor Type II Knockout Mitigates Inflammation and Improves Survival from Sepsis in Mice

Sepsis remains one of the leading causes of death worldwide. Oncostatin M (OSM), an interleukin (IL)-6 family cytokine, can be found at high levels in septic patients. However, little is known about its role in sepsis. This study aimed to determine if the genetic knockout of OSM receptor (OSMR) type II signaling would improve survival in a murine model of sepsis. Aged (>50 weeks) OSMR type II knockout (KO) mice and wild-type (WT) littermates received an intraperitoneal injection of fecal slurry (FS) or vehicle. The KO mice had better survival 48 h after the injection of FS than the WT mice (p = 0.005). Eighteen hours post-FS injection, the KO mice had reduced peritoneal, serum, and tissue cytokine levels (including IL-1β, IL-6, TNFα, KG/GRO, and IL-10) compared to the WT mice (p < 0.001 for all). Flow cytometry revealed decreased recruitment of CD11b⁺ F4/80⁺ Ly6c^high+ macrophages in the peritoneum of KO mice compared to WT mice (34 ± 6 vs. 4 ± 3%, P_Int = 0.005). Isolated peritoneal macrophages from aged KO mice had better live E. coli killing capacity than those from WT mice (p < 0.001). Peritoneal lavage revealed greater bacterial counts in KO mice than in WT mice (KO: 305 ± 22 vs. 116 ± 6 CFU (×10⁹)/mL; p < 0.001). In summary, deficiency in OSMR type II receptor signaling provided a survival benefit in the progression of sepsis. This coincided with reduced serum levels of pro-inflammatory (IL-1β, TNFα, and KC/GRO) and anti-inflammatory markers (IL-10), increased bacterial killing ability of macrophages, and reduced macrophage infiltration into to site of infection.

Acute and Long-Term Cardiovascular Complications among Patients with Sepsis and Septic Shock

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and is the leading cause of death within intensive care units (ICUs) [...].