Pulmonary hypertension due to acute respiratory distress syndrome

Mortality Due to Acute Respiratory Distress Syndrome in Latin America

OBJECTIVES

Mortality due to acute respiratory distress syndrome (ARDS) is a major global health problem. Knowledge of epidemiological data on ARDS is crucial to design management, treatment strategies, and optimize resources. There is ample data regarding mortality of ARDS from high-income countries; in this review, we evaluated mortality due to ARDS in Latin America.

DATA SOURCES

We searched in PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and Latin American and Caribbean Health Science Literature databases from 1967 to March 2023.

STUDY SELECTION

We searched prospective or retrospective observational studies and randomized controlled trials conducted in Latin American countries reporting ARDS mortality.

DATA EXTRACTION

Three pairs of independent reviewers checked all studies for eligibility based on their titles and abstracts. We performed meta-analysis of proportions using a random-effects model. We performed sensitivity analyses including studies with low risk of bias and with diagnosis using the Berlin definition. Subgroup analysis comparing different study designs, time of publication (up to 2000 and from 2001 to present), and studies in which the diagnosis of ARDS was made using Pa o2 /F io2 less than or equal to 200 and regional variations. Subsequently, we performed meta-regression analyses. Finally, we graded the certainty of the evidence (Grading of Recommendations Assessment, Development, and Evaluation).

DATA SYNTHESIS

Of 3315 articles identified, 32 were included (3627 patients). Mortality was 52% in the pooled group (low certainty of evidence). In the sensitivity analysis (according to the Berlin definition), mortality was 46% (moderate certainty of evidence). In the subgroup analysis mortality was 53% (randomized controlled trials), 51% (observational studies), 66% (studies published up to 2000), 50% (studies after 2000), 44% (studies with Pa o2 /F io2 ≤ 200), 56% (studies from Argentina/Brazil), and 40% (others countries). No variables were associated with mortality in the meta-regression.

CONCLUSIONS

ARDS mortality in Latin America remains high, as in other regions. These results should constitute the basis for action planning to improve the prognosis of patients with ARDS (PROSPERO [CRD42022354035]).

"When," "Where," and "How" of SARS-CoV-2 Infection Affects the Human Cardiovascular System: A Narrative Review

Coronavirus disease 2019 (COVID-19) is caused by the novel severe acute respiratory coronavirus-2 (SARS-CoV-2). Several explanations for the development of cardiovascular complications during and after acute COVID-19 infection have been hypothesized. The COVID-19 pandemic, caused by SARS-CoV-2, has emerged as one of the deadliest pandemics in modern history. The myocardial injury in COVID-19 patients has been associated with coronary spasm, microthrombi formation, plaque rupture, hypoxic injury, or cytokine storm, which have the same pathophysiology as the three clinical variants of Kounis syndrome. The angiotensin-converting enzyme 2 (ACE2), reninaldosterone system (RAAS), and kinin-kallikrein system are the main proposed mechanisms contributing to cardiovascular complications with the COVID-19 infection. ACE receptors can be found in the heart, blood vessels, endothelium, lungs, intestines, testes, neurons, and other human body parts. SARS-CoV-2 directly invades the endothelial cells with ACE2 receptors and constitutes the main pathway through which the virus enters the endothelial cells. This causes angiotensin II accumulation downregulation of the ACE2 receptors, resulting in prothrombotic effects, such as hemostatic imbalance via activation of the coagulation cascade, impaired fibrinolysis, thrombin generation, vasoconstriction, endothelial and platelet activation, and pro-inflammatory cytokine release. The KKS system typically causes vasodilation and regulates tissue repair, inflammation, cell proliferation, and platelet aggregation, but SARS-CoV-2 infection impairs such counterbalancing effects. This cascade results in cardiac arrhythmias, cardiac arrest, cardiomyopathy, cytokine storm, heart failure, ischemic myocardial injuries, microvascular disease, Kounis syndrome, prolonged COVID, myocardial fibrosis, myocarditis, new-onset hypertension, pericarditis, postural orthostatic tachycardia syndrome, pulmonary hypertension, stroke, Takotsubo syndrome, venous thromboembolism, and thrombocytopenia. In this narrative review, we describe and elucidate when, where, and how COVID-19 affects the human cardiovascular system in various parts of the human body that are vulnerable in every patient category, including children and athletes.

Cardiac arrhythmia and immune response in COVID-19 patients

The coronavirus disease 2019 (COVID-19) pandemic has presented substantial challenges for providing health care due to the numerous complications on the respiratory and cardiovascular systems of people. Cardiac arrhythmia is one of the cardiac complications, and it was observed in COVID-19 patients. Moreover, arrhythmia and cardiac arrest are common in COVID-19 patients in the intensive care unit. The occurrence of cardiac arrhythmia in COVID-19 patients is associated with hypoxia, cytokine storm, myocardial ischemia and inflammatory disease such as congestive heart failure. It is necessary to know the occurrence and mechanisms of tachyarrhythmia and bradyarrhythmia in patients with COVID-19 infection for their proper management. This review provides an overview of the association between COVID-19 and arrhythmias by detailing possible pathophysiological mechanisms.

Clinical characteristics of patients with a risk of pulmonary artery hypertension secondary to ARDS in a high-altitude area

BACKGROUND

Hypoxaemia plays an important role in the development of pulmonary artery hypertension (PAH). Patients with acute respiratory distress syndrome (ARDS) in a high-altitude area have different pathophysiological characteristics from those patients in the plains. The goal of our study was to explore the clinical characteristics of PAH secondary to ARDS in a high-altitude area.

METHODS

This was a prospective study conducted in the affiliated Hospital of Qinghai University. Two investigators independently assessed pulmonary artery pressure (PAP) and right ventricular function by transthoracic echocardiography. Basic information and clinical data of the patients who were enrolled were collected. A multivariable logistic regression model was used to evaluate the risk factors for PAH secondary to ARDS in the high-altitude area.

RESULTS

The incidence of PAH secondary to ARDS within 48 hours in the high-altitude area was 44.19%. Partial pressure of oxygen/fraction of inspired oxygen <165.13 mm Hg was an independent risk factor for PAH secondary to ARDS in the high-altitude area. Compared with the normal PAP group, the right ventricular basal dimensions were significantly larger and the right ventricular tricuspid annular plane systolic excursion was lower in the PAH group (right ventricular basal dimensions: 45.47±2.60 vs 40.67±6.12 mm, p=0.019; tricuspid annular plane systolic excursion (TAPSE): 1.82±0.40 vs 2.09±0.32 cm, p=0.021). The ratio of TAPSE to systolic PAP was lower in the PAH group (0.03±0.01 vs 0.08±0.03 cm/mm Hg, p<0.001).

CONCLUSIONS

The incidence of PAH in patients with ARDS in our study is high. PAH secondary to ARDS in a high-altitude area could cause right ventricular dysfunction.

TRIAL REGISTRATION NUMBER

NCT05166759.

Dysrhythmias associated with COVID-19: Review and management considerations

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is known to affect the cardiovascular system. Cardiac manifestations in COVID-19 can be due to direct damage to the myocardium and conduction system as well as by the disease's effect on the various organ systems. These manifestations include acute coronary syndrome, ST- segment elevations, cardiomyopathy, and dysrhythmias. Some of these dysrhythmias can be detrimental to the patient. Therefore, it is important for the emergency physician to be aware of the different arrhythmias associated with COVID-19 and how to manage them. This narrative review discusses the pathophysiology underlying the various arrhythmias associated with COVID-19 and their management considerations.

Acute Respiratory Distress Syndrome: Focus on Viral Origin and Role of Pulmonary Lymphatics

Acute respiratory distress syndrome (ARDS) is a serious affection of the lung caused by a variety of pathologies. Great interest is currently focused on ARDS induced by viruses (pandemic influenza and corona viruses). The review describes pulmonary changes in ARDS and specific effects of the pandemic viruses in ARDS, and summarizes treatment options. Because the known pathogenic mechanisms cannot explain all aspects of the syndrome, the contribution of pulmonary lymphatics to the pathology is discussed. Organization and function of lymphatics in a healthy lung and in resorption of pulmonary edema are described. A future clinical trial may provide more insight into the role of hyaluronan in ARDS but the development of promising pharmacological treatments is unlikely because drugs play no important role in lymphedema therapy.

Endothelial metabolism in pulmonary vascular homeostasis and acute respiratory distress syndrome

Capillary endothelial cells possess a specialized metabolism necessary to adapt to the unique alveolar-capillary environment. Here, we highlight how endothelial metabolism preserves the integrity of the pulmonary circulation by controlling vascular permeability, defending against oxidative stress, facilitating rapid migration and angiogenesis in response to injury, and regulating the epigenetic landscape of endothelial cells. Recent reports on single-cell RNA-sequencing reveal subpopulations of pulmonary capillary endothelial cells with distinctive reparative capacities, which potentially offer new insight into their metabolic signature. Lastly, we discuss broad implications of pulmonary vascular metabolism on acute respiratory distress syndrome, touching on emerging findings of endotheliitis in coronavirus disease 2019 (COVID-19) lungs.

Role of Sildenafil in Management of Pediatric Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) has high mortality and multiple therapeutic strategies have been used to improve the outcome. Inhaled nitric oxide (INO), a pulmonary vasodilator, is used to improve oxygenation. This study was conducted to determine the role of sildenafil, an oral vasodilator, to improve oxygenation and mortality in pediatric ARDS (PARDS). The prevalence of pulmonary hypertension in PARDS was studied as well. Inclusion criteria included children (1–18 years) with ARDS requiring invasive ventilation admitted to the pediatric intensive care unit of a teaching hospital in Northern India over a 1-year period of time. Thirty-five patients met the inclusion criteria. Cardiologist performed a detailed echocardiogram to determine pulmonary arterial pressure (PAP). Patients with persistent hypoxemia were started on oral sildenafil. The majority (77%) patients had a primary pulmonary etiology of PARDS. Elevated PAP (>25 mm Hg) was detected in 54.3% patients at admission. Sildenafil was given to 20 patients who had severe and persistent hypoxemia. Oxygenation improved in most patients after the first dose with statistically significant improvement in PaO2/FiO2 ratios at both 12 and 24 hours following initiation of therapeutic dosing of sildenafil. Improvement in oxygenation occurred irrespective of initial PAP. Outcomes included a total of 57.1% patients discharged, 28.6% discharged against medical advice (DAMA), and a 14.3% mortality rate. Mortality was related to the severity of PARDS and not the use of sildenafil. This is the first study to determine the effect of sildenafil in PARDS. Sildenafil led to improvement in oxygenation in nearly all the cases without affecting mortality. Due to unavailability of INO in most centers of developing countries, sildenafil may be considered as an inexpensive alternative in cases of persistent hypoxemia in PARDS. We recommend additional randomized controlled trials to confirm the effect of sildenafil in PARDS as determined in this study.

The impact of right ventricular injury on the mortality in patients with acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Previous studies have found various incidences of right ventricular (RV) injury and its association with clinical outcome in patients with acute respiratory distress syndrome (ARDS). In this systematic review and meta-analysis, we aimed to investigate the impact of the presence of RV injury on mortality in patients with ARDS.

METHOD

We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials for studies investigating the association between RV injury and mortality. Two authors independently evaluated whether studies meet eligibility criteria and extracted the selected patients' and studies' characteristics and outcomes. RV injury was diagnosed by trans-thoracic echocardiogram (TTE), trans-esophageal echocardiogram (TEE) and PAC (pulmonary artery catheter) in the included studies. The primary outcome was the association between mortality and the presence of RV injury in patients with ARDS. The overall reported mortality was defined as either the intensive care unit (ICU) mortality, in-hospital mortality, or mortality within 90 days, and short-term mortality was defined as ICU-mortality, in-hospital mortality, or mortality within 30 days.

RESULTS

We included 9 studies (N = 1861 patients) in this meta-analysis. RV injury that included RV dysfunction, RV dysfunction with hemodynamic compromise, RV failure, or acute cor-pulmonale was present in 21.0% (391/1,861). In the pooled meta-analysis, the presence of RV injury in patients with ARDS was associated with significantly higher overall mortality (OR 1.45, 95% CI 1.13-1.86, p-value = 0.003, I² = 0%), as well as short-term mortality (OR 1.48, 95% CI 1.14-1.93, p-value = 0.003, I² = 0%).

CONCLUSION

In this systematic review and meta-analysis including 1861 patients with ARDS, the presence of RV injury was significantly associated with increased overall and short-term mortality.

TRIAL REGISTRATION

The protocol was registered at PROSPERO (CRD42020206521).

Extracorporeal Membrane Oxygenation with Right Ventricular Assist Device for COVID-19 ARDS

Background: Right ventricular failure is an underrecognized consequence of COVID-19 pneumonia. Those with severe disease are treated with extracorporeal membrane oxygenation (ECMO) but with poor outcomes. Concomitant right ventricular assist device (RVAD) may be beneficial.

Methods: A retrospective analysis of intensive care unit patients admitted with COVID-19 ARDS (Acute Respiratory Distress Syndrome) was performed. Nonintubated patients, those with acute kidney injury, and age > 75 were excluded. Patients who underwent RVAD/ECMO support were compared with those managed via invasive mechanical ventilation (IMV) alone. The primary outcome was in-hospital mortality. Secondary outcomes included 30-d mortality, acute kidney injury, length of ICU stay, and duration of mechanical ventilation.

Results: A total of 145 patients were admitted to the ICU with COVID-19. Thirty-nine patients met inclusion criteria. Of these, 21 received IMV, and 18 received RVAD/ECMO. In-hospital (52.4 versus 11.1%, P = 0.008) and 30-d mortality (42.9 versus 5.6%, P= 0.011) were significantly lower in patients treated with RVAD/ECMO. Acute kidney injury occurred in 15 (71.4%) patients in the IMV group and zero RVAD/ECMO patients (P< 0.001). ICU (11.5 versus 21 d, P= 0.067) and hospital (14 versus 25.5 d, P = 0.054) length of stay were not significantly different. There were no RVAD/ECMO device complications. The duration of mechanical ventilation was not significantly different (10 versus 5 d, P = 0.44).

Conclusions: RVAD support at the time of ECMO initiation resulted in the no secondary end-organ damage and higher in-hospital and 30-d survival versus IMV in specially selected patients with severe COVID-19 ARDS. Management of severe COVID-19 ARDS should prioritize right ventricular support.

Mechanisms of Pulmonary Hypertension in Acute Respiratory Distress Syndrome (ARDS)

Background: Acute respiratory distress syndrome (ARDS) is a severe and often fatal disease. The causes that lead to ARDS are multiple and include inhalation of salt water, smoke particles, or as a result of damage caused by respiratory viruses. ARDS can also arise due to systemic complications such as blood transfusions, sepsis, or pancreatitis. Unfortunately, despite a high mortality rate of 40%, there are limited treatment options available for ARDS outside of last resort options such as mechanical ventilation and extracorporeal support strategies. Aim of review: A complication of ARDS is the development of pulmonary hypertension (PH); however, the mechanisms that lead to PH in ARDS are not fully understood. In this review, we summarize the known mechanisms that promote PH in ARDS. Key scientific concepts of review: (1) Provide an overview of acute respiratory distress syndrome; (2) delineate the mechanisms that contribute to the development of PH in ARDS; (3) address the implications of PH in the setting of coronavirus disease 2019 (COVID-19).

Pulmonary hypertension and right ventricular involvement in hospitalised patients with COVID-19

OBJECTIVE

To assess the prevalence, characteristics and prognostic value of pulmonary hypertension (PH) and right ventricular dysfunction (RVD) in hospitalised, non-intensive care unit (ICU) patients with coronavirus disease 2019 (COVID-19).

METHODS

This single-centre, observational, cross-sectional study included 211 patients with COVID-19 admitted to non-ICU departments who underwent a single transthoracic echocardiography (TTE). Patients with poor acoustic window (n=11) were excluded. Clinical, imaging, laboratory and TTE findings were compared in patients with versus without PH (estimated systolic pulmonary artery pressure >35 mm Hg) and with versus without RVD (tricuspid annular plane systolic excursion <17 mm or S wave <9.5 cm/s). The primary endpoint was in-hospital death or ICU admission.

RESULTS

A total of 200 patients were included in the final analysis (median age 62 (IQR 52-74) years, 65.5% men). The prevalence of PH and RVD was 12.0% (24/200) and 14.5% (29/200), respectively. Patients with PH were older and had a higher burden of pre-existing cardiac comorbidities and signs of more severe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (radiological lung involvement, laboratory findings and oxygenation status) compared with those without PH. Conversely, patients with RVD had a higher burden of pre-existing cardiac comorbidities but no evidence of more severe SARS-CoV-2 infection compared with those without RVD. The presence of PH was associated with a higher rate of in-hospital death or ICU admission (41.7 vs 8.5%, p<0.001), while the presence of RVD was not (17.2 vs 11.7%, p=0.404).

CONCLUSIONS

Among hospitalised non-ICU patients with COVID-19, PH (and not RVD) was associated with signs of more severe COVID-19 and with worse in-hospital clinical outcome.

TRIAL REGISTRATION NUMBER

NCT04318366.

Arrhythmias and COVID-19: A Review

Current understanding of the impact of coronavirus disease-2019 (COVID-19) on arrhythmias continues to evolve as new data emerge. Cardiac arrhythmias are more common in critically ill COVID-19 patients. The potential mechanisms that could result in arrhythmogenesis among COVID-19 patients include hypoxia caused by direct viral tissue involvement of lungs, myocarditis, abnormal host immune response, myocardial ischemia, myocardial strain, electrolyte derangements, intravascular volume imbalances, and drug sides effects. To manage these arrhythmias, it is imperative to increase the awareness of potential drug-drug interactions, to monitor QTc prolongation while receiving COVID therapy and provide special considerations for patients with inherited arrhythmia syndromes. It is also crucial to minimize exposure to COVID-19 infection by stratifying the need for intervention and using telemedicine. As COVID-19 infection continues to prevail with a potential for future surges, more data are required to better understand pathophysiology and to validate management strategies.

Desperate Times, Desperate Measures: The Case for RRx-001 in the Treatment of COVID-19

This article summarizes the likely attenuation properties of RRx-001 in COVID-19 based on its mechanism of action and the putative pathogenesis of the disease, which appears to activate inflammatory, oxidative, and immune cascades with the potential to culminate in acute respiratory distress syndrome, cytokine storm and death. An ongoing pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 appears to present with 3 major patterns of clinical symptomatology: (1) mild upper respiratory tract infection, (2) non–life-threatening pneumonia, and (3) severe pneumonia and acute respiratory distress syndrome that initially manifest as a mild prodrome lasting for 7–8 days before rapid clinical and radiological deterioration requiring ICU transfer.

RRx-001 is a targeted nitric oxide donor. This small molecule, which has been evaluated in multiple Phase 1–2 clinical trials for cancer as well as a Phase 3 clinical trial for the treatment of small cell lung cancer called REPLATINUM (NCT03699956), is minimally toxic and demonstrates clear evidence of antitumor activity. During the course of these clinical trials it was noted that the rate of chronic obstructive pulmonary disease exacerbation and pneumonia in actively smoking small cell lung cancer patients treated with RRx-001 is less than 1%. Due to extensive history of tobacco use, 40%–70% of patients with lung cancer have chronic obstructive pulmonary disease and the expected rate of pulmonary infection in this population is 50%–70%, which was not observed in RRx-001 clinical trials. Moreover, in preclinical studies of pulmonary hypertension, RRx-001 was found to be comparable with or more effective than the FDA approved agent, Bosentan. The potential pulmonary protective effects of RRx-001 in patients with recurrent lung infections coupled with preclinical models demonstrating RRx-001-mediated reversal of pulmonary hypertension suggests RRx-001 may have therapeutic activity in patients with acute respiratory symptoms due to COVID 19. Clinical trials have been initiated to confirm the hypothesis that RRx-001 may be repurposed to treat SARS-CoV-2 infection.

Incidence Proportion of Acute Cor Pulmonale in Patients with Acute Respiratory Distress Syndrome Subjected to Lung Protective Ventilation: A Systematic Review and Meta-analysis

INTRODUCTION

Reported incidence of acute cor pulmonale (ACP) in patients with acute respiratory distress syndrome (ARDS) varies from 10% to 84%, despite being subjected to lung protective ventilation according to the current guidelines. The objective of this review is to find pooled cumulative incidence of ACP in patients with ARDS undergoing lung protective ventilation.

MATERIALS AND METHODS

We searched MEDLINE, EMBASE, Cochrane Library, KoreaMed, LILACS, and WHO Clinical Trial Registry. Cross-sectional or cohort studies were included if they reported or provided data that could be used to calculate the incidence proportion of ACP. Inverse variance heterogeneity (IVhet) and random effect model were used for the main outcome and measures.

RESULTS

We included 16 studies encompassing 1661 patients. The cumulative incidence of ACP using IVhet analysis was 23% (95% confidence interval [CI] = 18%-28%) over 3 days of lung protective ventilation. Random effect analysis of 7 studies (1250 patients) revealed pooled odd ratio of mortality of 1.16 (95% CI = 0.80-1.67, P = 0.44) due to ACP.

CONCLUSION

Patients with ARDS have a 23% risk of developing ACP with lung protective ventilation. Findings of this review indicate the need of updating existing guidelines for ventilating ARDS patients to incorporate right ventricle protective strategy.