Diuretic vs. placebo in intermediate-risk acute pulmonary embolism: a randomized clinical trial

Management Strategies for Acute Pulmonary Embolism in the ICU

TOPIC IMPORTANCE

Acute pulmonary embolism (PE) is a common disease encountered by pulmonologists, cardiologists, and critical care physicians throughout the world. For patients with high-risk acute PE (defined by systemic hypotension) and intermediate high-risk acute PE (defined by the absence of systemic hypotension, but the presence of numerous other concerning clinical and imaging features), intensive care often is necessary. Initial management strategies should focus on optimization of right ventricle (RV) function while decisions about advanced interventions are being considered.

REVIEW FINDINGS

We reviewed the existing literature of various vasoactive agents, IV fluids and diuretics, and pulmonary vasodilators in both animal models and human trials of acute PE. We also reviewed the potential complications of endotracheal intubation and positive pressure ventilation in acute PE. Finally, we reviewed the data of venoarterial extracorporeal membrane oxygenation use in acute PE. The above interventions are discussed in the context of the underlying pathophysiologic features of acute RV failure in acute PE with corresponding illustrations.

SUMMARY

Norepinephrine is a reasonable first choice for hemodynamic support with vasopressin as an adjunct. IV loop diuretics may be useful if evidence of RV dysfunction or volume overload is present. Fluids should be given only if concern exists for hypovolemia and absence of RV dilatation. Supplemental oxygen administration should be considered even without hypoxemia. Positive pressure ventilation should be avoided if possible. Venoarterial extracorporeal membrane oxygenation cannulation should be implemented early if ongoing deterioration occurs despite these interventions.

Comparison of diuretics and fluid expansion in the initial treatment of patients with normotensive acute pulmonary embolism: a systematic review and meta-analysis

BACKGROUND

Right ventricular (RV) dysfunction is the main cause of death in patients with normotensive acute pulmonary embolism (PE). The optimal management for this subset of patients remains uncertain. This systematic review and meta-analysis focused on the comparison of diuretics and fluid expansion in patients with acute PE presenting with RV dysfunction and haemodynamic stability.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines considering only RTCs. The authors searched the traditional and grey literature through 1 November 2022. Meta-analysis used open source packages in R. Inverse variance fixed-effects models with OR as the effect measure were used for primary analyses. The main outcomes defined in this review protocol included pulmonary arterial systolic pressure (PASP), creatinine value changes and N-terminal pro-B-type natriuretic peptide during the first 24 hours.

RESULTS

Four studies with a total of 452 patients met the inclusion criteria. The baseline characteristics of patients were similar across all studies. Overall, patients receiving diuretics had a significant 24 hours reduction in pro-B-type natriuretic peptide (standard mean difference of -41.97; 95% CI -65.79 to -18.15), and PASP (standard mean difference of -5.96; 95% CI -8.06 to -3.86). This group had significantly higher creatinine levels (standard mean difference of 7.74; 95% CI 5.04 to 10.45). The quality of the studies was heterogeneous; two had a low risk of bias, and the other two had a high risk of bias.

CONCLUSIONS

Very few studies have compared the efficacy and safety of diuretics and fluid expansion in normotensive patients with acute PE with RV failure. Overall, furosemide appears to reduce RV dysfunction in this subset of patients compared with fluid expansion. Further research is required to confirm these findings.

Right Ventricular Recovery: Early and Late Changes after Acute PE Diagnosis

Right ventricular (RV) failure is a critical cause of morbidity and mortality in patients presenting with pulmonary embolism (PE). The presentation of RV failure is based on the combination of clinical findings, laboratory abnormalities, and imaging evidence. An improved understanding of the pathophysiology of RV dysfunction following PE has given rise to more accurate risk stratification and broader therapeutic approaches. A subset of patients with PE develop chronic RV dysfunction with or without pulmonary hypertension. In this review, we focus on the impact of PE on the RV and its implications for risk stratification, prognosis, acute management, and long-term therapy.

Ventricular interdependence in critically ill patients: from physiology to bedside

The review focuses on the mechanism of ventricular interdependence, a frequently encountered phenomena, especially in critically ill patients. It is explained by the anatomy of the heart, with two ventricles sharing a common wall, the septum, and nested in an acutely inextensible envelope, the pericardium. In pathological situation, it results in abnormal movements of the interventricular septum driven by respiration, leading to abnormal filling of one or the other ventricle. Ventricular interdependence has several clinical applications and explains some situations of hemodynamic impairment, especially in situations of cardiac tamponade, severe acute asthma, right ventricular (RV) overload, or more simply, in case of positive pressure ventilation with underlying acute pulmonary hypertension. Ventricular interdependence can be monitored with pulmonary arterial catheter or echocardiography. Knowledge of this phenomena has very concrete clinical applications in the management of filling or in the prevention or treatment of RV overload.

Mechanical Circulatory Support and Critical Care Management of High-Risk Acute Pulmonary Embolism

Hemodynamically significant pulmonary embolism (PE) remains a widely prevalent, underdiagnosed condition associated with mortality rates as high as 30%. The main driver of poor outcomes is acute right ventricular failure that remains clinically challenging to diagnose and requires critical care management. Treatment of high-risk (or massive) acute PE has traditionally included systemic anticoagulation and thrombolysis. Mechanical circulatory support, including both percutaneous and surgical approaches, are emerging as treatment options for refractory shock due to acute right ventricular failure in the setting of high-risk acute pulmonary embolism.

Hemodynamic and respiratory support in pulmonary embolism: a narrative review

Pulmonary embolism is a common and potentially fatal disease, with a significant burden on health and survival. Right ventricular dysfunction and hemodynamic instability are considered two key determinants of mortality in pulmonary embolism, which can reach up to 65% in severe cases. Therefore, timely diagnosis and management are of paramount importance to ensure the best quality of care. However, hemodynamic and respiratory support, both major constituents of management in pulmonary embolism, associated with cardiogenic shock or cardiac arrest, have been given little attention in recent years, in favor of other novel advances such as systemic thrombolysis or direct oral anticoagulants. Moreover, it has been implied that current recommendations regarding this supportive care lack enough robustness, further complicating the problem. In this review, we critically discuss and summarize the current literature concerning the hemodynamic and respiratory support in pulmonary embolism, including fluid therapy, diuretics, pharmacological support with vasopressors, inotropes and vasodilators, oxygen therapy and ventilation, and mechanical circulatory support with veno-arterial extracorporeal membrane oxygenation and right ventricular assist devices, while also providing some insights into contemporary research gaps.

Risk stratification and treatment of pulmonary embolism with intermediate-risk of mortality

PURPOSE OF REVIEW

Intermediate-risk pulmonary embolisms (PE) represent a heterogeneous group at the high end of hemodynamically stable patients, characterized by a higher mortality rate. This challenging population gathers many unsolved question regarding its therapeutic management. The purpose of this review is to provide an updated overview of the literature regarding further risk stratification and treatment options in this population.

RECENT FINDINGS

If anticoagulation represents the undisputed first line of treatment, some patients especially in the intermediate-high risk subgroup may necessitate or could benefit from therapeutic escalation with reperfusion therapies. This includes systemic thrombolysis (ST) or catheter-directed therapies (CDT). ST, despite its high efficacy, is not recommended in this population because of prohibitive bleeding complications. Therefore, reduced-dose ST appears to be a promising option and is actually under evaluation. CDT are percutaneous reperfusion techniques developed to acutely decrease pulmonary vascular obstruction with lower-dose or no thrombolytic agents and, thus, potentially improved safety compared to ST.

SUMMARY

Great progress has been made in the recent years providing a wide range of therapeutic options. Optimal selection of patients who could benefit from these treatments is the key and is based on clinical, biological and radiological parameters evaluating right ventricle function and allowing accurate risk stratification. Pulmonary Embolism Response Team represents an efficient modality for therapeutic management especially in the intermediate-high risk subgroup.

Diuretics Versus Volume Expansion in the Initial Management of Acute Intermediate High-Risk Pulmonary Embolism

AIMS

The very early management of pulmonary embolism (PE), a part from antithrombotic treatment, has been little studied. Our aim was to compare the effects of diuretic therapy (DT) versus volume expansion (VE) in patients hospitalized for PE with RV dysfunction.

METHODS AND RESULTS

We conducted a randomized open-label multicentric study including patients with intermediate high-risk PE. Patients were randomized between diuretics or saline infusion. The primary endpoint was time to troponin (Tp) normalization. Secondary endpoints were time to normalization of B-type natriuretic peptide (BNP), changes in echocardiographic RV function parameters and treatment tolerance. Sixty patients presenting intermediate high-risk PE were randomized. Thirty received DT and 30 VE. We noted no changes in Tp kinetics between the two groups. In contrast, faster normalization of BNP was obtained in the DT group: 56 [28-120] vs 108 [48-144] h: p = 0.05, with a shorter time to 50%-decrease from peak value 36 [24-48] vs 54 [41-67] h, p = 0.003 and a higher rate of patients with a lower BNP concentration within the first 12 h (42% vs 12% p < 0.001). RV echocardiographic parameters were unchanged between the groups. One dose 40 mg furosemide was well-tolerated and not associated with any serious adverse events.

CONCLUSION

In the acute management of intermediate high-risk PE, initial therapy including diuretic treatment is well-tolerated and safe. Although changes in Tp kinetics and echocardiographic RV dysfunction parameters did not differ, normalization of BNP is achieved more quickly in the DT group. This finding, which need to be confirmed in trials with clinical end points, may reflects a rapid improvement in RV function using one dose 40 mg furosemide.

TRIAL REGISTRY

Clinical Trial Registration NCT02531581.