Doppler-defined pulmonary hypertension in medical intensive care unit patients: Retrospective investigation of risk factors and impact on mortality

Emergencies in Pulmonary Hypertension

Pulmonary hypertension is a challenging disease entity with various underlying etiologies. The management of patients with pulmonary arterial hypertension (WHO Group 1) remains challenging especially in the critical care setting. With risk of high morbidity and mortality, these patients require a multidisciplinary team approach at a speciality care facility for pulmonary hypertension for comprehensive evaluation and rapid initiation of treatment. For acute decompensated right heart failure, management should concentrate on optimizing preload and after load with use of pulmonary vasodilator therapy. A careful evaluation of specialized situations is required for appropriate treatment response.

Echocardiographic parameters and hemodynamic instability at the initiation of continuous kidney replacement therapy

OBJECTIVE

Investigate the association of echocardiographic parameters with hemodynamic instability after initiating continuous kidney replacement therapy (CKRT) in a cohort of intensive care unit (ICU) patients requiring CKRT.

METHODS

Historical cohort study of consecutive adults admitted to the ICU at a tertiary care hospital from December 2006 through November 2015 who underwent CKRT and had an echocardiogram done within seven days before CKRT initiation. The primary outcome was hypotension within one hour of CKRT initiation.

RESULTS

We included 980 patients, 804 (82%) with acute kidney injury (AKI) and 176 (18%) with end-stage kidney disease (ESKD). Median patient age was 63 (± 14) years, and median Sequential Organ Failure Assessment (SOFA) score on the day of CKRT initiation was 12 (IQR 10-14). Multivariable analysis showed that Left (OR 2.01, 95% CI 1.04-3.86), and Right (OR 1.5, 95% CI 1.04-2.25) moderate and severe ventricular enlargement, Vasoactive-Inotropic Score (VIS) one hour before CKRT initiation (OR 1.18 per 10 units increase, 95% CI 1.09-1.28) and high bicarbonate fluid replacement (OR 2.52, 95% CI 1.01-6.2) were associated with hypotension after CKRT initiation.

CONCLUSION

Right and left ventricular enlargement are risk factors associated with hypotension after CKRT initiation.

Bedside Ultrasound for Hemodynamic Monitoring in Cardiac Intensive Care Unit

Thanks to the advances in medical therapy and assist devices, the management of patients hospitalized in cardiac intensive care unit (CICU) is becoming increasingly challenging. In fact, Patients in the cardiac intensive care unit are frequently characterized by dynamic and variable diseases, which may evolve into several clinical phenotypes based on underlying etiology and its complexity. Therefore, the use of noninvasive tools in order to provide a personalized approach to these patients, according to their phenotype, may help to optimize the therapeutic strategies towards the underlying etiology. Echocardiography is the most reliable and feasible bedside method to assess cardiac function repeatedly, assisting clinicians not only in characterizing hemodynamic disorders, but also in helping to guide interventions and monitor response to therapies. Beyond basic echocardiographic parameters, its application has been expanded with the introduction of new tools such as lung ultrasound (LUS), the Venous Excess UltraSound (VexUS) grading system, and the assessment of pulmonary hypertension, which is fundamental to guide oxygen therapy. The aim of this review is to provide an overview on the current knowledge about the pathophysiology and echocardiographic evaluation of perfusion and congestion in patients in CICU, and to provide practical indications for the use of echocardiography across clinical phenotypes and new applications in CICU.

Association of Pulmonary Hypertension with Survival and Neurologic Outcomes in Adults with In-Hospital Cardiac Arrest

BACKGROUND

Pulmonary hypertension (PH) has been associated with poor survival in multiple cardiopulmonary conditions, however its association with outcomes in cardiac arrest remains unknown. We aimed to evaluate the association of PH with survival and neurologic outcomes in adults with in-hospital cardiac arrest (IHCA).

METHODS

The study population included adults with IHCA undergoing resuscitation at an academic tertiary medical center from 2011-2019. Patients were classified based upon the presence versus absence of PH, defined as a pulmonary artery systolic pressure > 35mmHg on pre-arrest echocardiogram. Survival to discharge and favorable neurological outcome (defined as a Glasgow Outcome Score of 4-5) served as the primary and secondary outcomes of interest respectively.

RESULTS

Of the 371 patients studied, 203 (54.7%) had PH while 168 (45.3%) did not. Patients with PH had higher Charlson Comorbidity Score with higher rates of multiple baseline comorbidities. They also had worse multi-chamber enlargement, left ventricular diastolic dysfunction, right ventricular systolic dysfunction, and valvular heart disease compared to non-PH patients. Rates of survival to discharge (11.5% vs 10.9%, p=0.881) and favorable neurologic outcome (8.0% vs 6.2%, p=0.550) were similar in PH and non-PH patients respectively. In multivariable analysis, PH was not associated with survival to discharge (OR 1.23, 95%CI 0.57-2.65) or favorable neurologic outcome (OR 1.69, 95%CI 0.64 - 4.45).

CONCLUSIONS

In this contemporary registry of adults with IHCA, while PH was associated with a higher risk patient profile, it was not associated with survival or neurologic outcomes in this population.

Epidemiology and outcomes of pulmonary hypertension in the cardiac intensive care unit

AIMS

Pulmonary hypertension (PH) has been consistently associated with adverse outcomes in hospitalized patients. Limited epidemiologic data exist regarding PH in the cardiac intensive care unit (CICU) population. Here, we describe the prevalence, aetiology, and outcomes of PH in the CICU.

METHODS AND RESULTS

Cardiac intensive care unit patients admitted from 2007 to 2018 who had right ventricular systolic pressure (RVSP) measured via transthoracic echocardiography near CICU admission were included. PH was defined as RVSP >35 mmHg, and moderate-to-severe PH as RVSP ≥50 mmHg. Predictors of in-hospital mortality were determined using multivariable logistic regression. Among 5042 patients (mean age 69.4 ± 14.8 years; 41% females), PH was present in 3085 (61%). The majority (68%) of patients with PH had left heart failure, and 29% had lung disease. In-hospital mortality occurred in 8.3% and was more frequent in patients with PH [10.9% vs. 4.2%, adjusted odds ratio (OR) 1.40, 95% confidence interval (CI) 1.03-1.92, P = 0.03], particularly patients with moderate-to-severe PH (14.4% vs. 6.2%, adjusted OR 1.65, 95% CI 1.27-2.14, P < 0.001). In-hospital mortality increased incrementally as a function of higher RVSP (adjusted 1.18 per 10 mmHg increase, 95% CI 1.09-1.28, P < 0.001). Patients with higher RVSP or moderate-to-severe PH had increased in-hospital mortality across admission diagnoses (all P < 0.05).

CONCLUSIONS

Pulmonary hypertension is very common in the CICU population and appears to be independently associated with a higher risk of death during hospitalization, although the strength of this association varies according to the underlying admission diagnosis. These data highlight the importance of PH in patients with cardiac critical illness.

Critical care management of the patient with pulmonary hypertension

Pulmonary hypertension (PH) is a common diagnosis in patients admitted to the cardiac intensive care unit with a wide range of underlying causes. A detailed evaluation to identify all factors contributing to the elevated pulmonary artery pressure and provide an assessment of right ventricular haemodynamics and function is needed to guide treatment and identify patients at highest risk for poor outcomes. While in many patients management of underlying and triggering medical problems with careful monitoring is appropriate, a subset of patients may benefit from specialized treatments targeting the pulmonary circulation and support of the right ventricle. In such cases, collaboration with or transfer to a centre with special expertise in the management of PH may be warranted.

Acute pulmonary hypertension and short-term outcomes in severe Covid-19 patients needing intensive care

Introduction

Critically ill Covid‐19 pneumonia patients are likely to develop the sequence of acute pulmonary hypertension, right ventricular (RV) strain, and eventually RV failure due to known pathophysiology (endothelial inflammation plus thrombo‐embolism) that promotes increased pulmonary vascular resistance and pulmonary artery pressure. This study aimed to investigate the occurrence of acute pulmonary hypertension (aPH) as per established trans‐thoracic echocardiography (TTE) criteria in Covid‐19 patients receiving intensive care and to explore whether short‐term outcomes are affected by the presence of aPH.

Methods

Medical records were reviewed for patients treated in the intensive care units at a tertiary university hospital over a month. The presence of aPH on the TTE was noted, and plasma NTproBNP and troponin were measured as markers of cardiac failure and myocardial injury, respectively. Follow‐up data were collected 21 d after the performance of TTE.

Results

In total, 26 of 67 patients (39%) had an assessed systolic pulmonary artery pressure of > 35 mmHg (group aPH), meeting the TTE definition of aPH. NTproBNP levels (median [range]: 1430 [102‐30 300] vs. 470 [45‐29 600] ng L⁻¹; P = .0007), troponin T levels (63 [22‐352] vs. 15 [5‐407] ng L⁻¹; P = .0002), and the 21‐d mortality rate (46% vs. 7%; P < .001) were substantially higher in patients with aPH compared to patients not meeting aPH criteria.

Conclusion

TTE‐defined acute pulmonary hypertension was frequently observed in severely ill Covid‐19 patients. Furthermore, aPH was linked to biomarker‐defined myocardial injury and cardiac failure, as well as an almost sevenfold increase in 21‐d mortality.

Right Ventricular Pulmonary Artery Coupling and Mortality in Cardiac Intensive Care Unit Patients

Background

Impaired right ventricular (RV) pulmonary artery coupling has been associated with higher mortality in patients with chronic heart disease, but few studies have examined this metric in critically ill patients. We sought to evaluate the association between RV pulmonary artery coupling, defined by the ratio of tricuspid annular peak systolic tissue Doppler velocity (TASV)/estimated RV systolic pressure (RVSP), and mortality in cardiac intensive care unit patients.

Methods and Results

Using a database of unique cardiac intensive care unit admissions from 2007 to 2018, we included patients with TASV/RVSP ratio measured within 1 day of hospitalization. Hospital mortality was analyzed using multivariable logistic regression, and 1‐year mortality was analyzed using multivariable Cox proportional‐hazards analysis. We included 4259 patients with a mean age of 69±15 years (40.1% women). Admission diagnoses included acute coronary syndrome in 56%, heart failure in 52%, respiratory failure in 24%, and cardiogenic shock in 12%. The mean TASV/RVSP ratio was 0.31±0.14, and in‐hospital mortality occurred in 7% of patients. Higher TASV/RVSP ratio was associated with lower in‐hospital mortality (adjusted unit odds ratio, 0.68 per each 0.1‐unit higher ratio; 95% CI, 0.58–0.79; P<0.001) and lower 1‐year mortality among hospital survivors (adjusted unit hazard ratio, 0.83 per each 0.1‐unit higher ratio; 95% CI, 0.77–0.90; P<0.001). Stepwise decreases in hospital and 1‐year mortality were observed in each higher TASV/RVSP quintile. The TASV/RVSP ratio remained associated with mortality after adjusting for left ventricular systolic and diastolic function.

Conclusions

A low TASV/RVSP ratio is associated with increased short‐term and long‐term mortality among cardiac intensive care unit patients, emphasizing importance of impaired RV pulmonary artery coupling as a determinant of poor prognosis. Further study is required to determine whether interventions to optimize RV pulmonary artery coupling can improve outcomes.

Change in right ventricular systolic function after continuous renal replacement therapy initiation and renal recovery

OBJECTIVE

To describe the associations between right ventricular (RV) function and outcomes of patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT).

METHODS

This is a retrospective study, conducted 2006-2015 at an academic hospital in USA. We included patients with AKI requiring CRRT who had paired echocardiograms within 2 weeks before and after CRRT initiation. We defined improvement in RV systolic function as 2-point improvement on the semiquantitative scale.

RESULTS

The cohort included 201 patients. The mean(±SD) age was 59(±16) years with 83(41%) female. The median time of the pre and post echocardiograms relative to CRRT initiation were - 1 day (IQR-3;0) prior to and 3 days (IQR1;7) after CRRT initiation. Thirty-one (15%) patients showed an improvement in their RV function. Using a multivariable logistic regression model, improvement in RV systolic function was associated with lower odds of major adverse kidney events (composite of mortality, need for dialysis or persistently elevated serum creatinine) at 90 days with odds ratio (OR) of 0.37(95%CI:0.17-0.84, p.016). Positive cumulative fluid balance was associated with lower odds of improvement in RV function (OR 0.95 per 1-l increase, p 0.045).

CONCLUSION

Serial assessment of RV function among patients with AKI requiring CRRT could provide prognostic value.

A Comparative Study of Inhaled Nitric Oxide and an Intravenously Administered Nitric Oxide Donor in Acute Pulmonary Hypertension

Purpose

Inhaled nitric oxide (iNO) selectively vasodilates the pulmonary circulation but the effects are sometimes insufficient. Available intravenous (iv) substances are non-selective and cause systemic side effects. The pulmonary and systemic effects of iNO and an iv mono-organic nitrite (PDNO) were compared in porcine models of acute pulmonary hypertension.

Methods

In anesthetized piglets, dose–response experiments of iv PDNO at normal pulmonary arterial pressure (n=10) were executed. Dose–response experiments of iv PDNO (n=6) and iNO (n=7) were performed during pharmacologically induced pulmonary hypertension (U46619 iv). The effects of iv PDNO and iNO were also explored in 5 mins of hypoxia-induced increase in pulmonary pressure (n=2-4).

Results

PDNO (15, 30, 45 and 60 nmol NO kg⁻¹ min⁻¹ iv) and iNO (5, 10, 20 and 40 ppm which corresponded to 56, 112, 227, 449 nmol NO kg⁻¹ min⁻¹, respectively) significantly decreased the U46619-increased mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR) to a similar degree without significant decreases in mean arterial pressure (MAP) or systemic vascular resistance (SVR). iNO caused increased levels of methemoglobin. At an equivalent delivered NO quantity (iNO 5 ppm and PDNO 45 nmol kg⁻¹ min⁻¹ iv), PDNO decreased PVR and SVR significantly more than iNO. Both drugs counteracted hypoxia-induced pulmonary vasoconstriction and they decreased the ratio of PVR and SVR in both settings.

Conclusion

Intravenous PDNO was a more potent pulmonary vasodilator than iNO in pulmonary hypertension, with no severe side effects. Hence, this study supports the potential of iv PDNO in the treatment of acute pulmonary hypertension.

Blood transfusions, blood storage, and correlation with elevated pulmonary arterial pressures

BACKGROUND

The aim of this study was to determine if transfusion with RBCs is associated with a rise in mean pulmonary artery pressure (MPAP) and whether such a rise is influenced by the duration of RBC storage.

STUDY DESIGN AND METHODS

A retrospective chart review of intensive care unit patients with pulmonary artery catheters was conducted at two military medical centers.

RESULTS

RBC transfusion is associated with a sustained (≥4 hours) statistically significant 2- to 3-mm Hg rise in MPAP relative to both pretransfusion levels (p < 0.05) and compared to asanguinous fluid infusions (p < 0.05). The magnitude of the rise (all infusions, RBCs, and asanguinous) correlates positively with in-hospital mortality (p < 0.01) and hospital length of stay (p < 0.01). The duration of RBC storage was not statistically correlated with the magnitude of rise in the population studied. Mean infusion volume was greater for RBC (vs. asanguinous) infusions, but volume adjustment of MPAP values did not alter the pattern or statistical significance of the results.

CONCLUSIONS

Analysis of retrospectively collected data suggests that transfusion of RBC-containing fluids results in a sustained elevation of MPAP. In the patient population studied, the duration of RBC storage did not correlate with the magnitude of MPAP rise. Future prospective studies of transfusion effects should consider including assessment of MPAP and subpopulation analyses.

Echocardiographic parameters of patients in the intensive care unit undergoing continuous renal replacement therapy

MAIN OBJECTIVES

Echocardiographic parameters have been used to predict outcomes for specific intensive care unit (ICU) populations. We sought to define echocardiographic parameters for ICU patients receiving continuous renal replacement therapy (CRRT).

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

This is a historical cohort study of consecutive ICU patients at Mayo Clinic (Rochester, Minnesota) who received CRRT from December 9, 2006, through November 13, 2015. Only patients with an echocardiographic examination within 7 days of CRRT initiation were considered.

RESULTS

The study included 1,276 patients. Decreased left ventricular ejection fraction (LVEF; ≤45%) was noted in 361/1,120 (32%) and increased right ventricular systolic pressure (RVSP; ≥40 mm Hg) was noted in 529/798 (66%). Right ventricular systolic dysfunction was observed in 320/820 (39%). The most common valvular abnormality was tricuspid regurgitation (244/1,276 [19%]). Stratification of these parameters by ICU type (medical, surgical, cardiothoracic, cardiac) showed that most echocardiographic abnormalities were significantly more prevalent among cardiac ICU patients: LVEF ≤45% (67/105 [64%]), RVSP ≥40 mm Hg (63/79 [80%]) and tricuspid regurgitation (50/130 [38%]). We compared patients with acute kidney injury (AKI) vs end-stage renal disease and showed that decreased LVEF (284/921 [31%] vs 78/201 [39%]), was significantly less prevalent among patients with AKI, but increased RVSP was more prevalent (445/651 [68%] vs 84/147 [57%]) with AKI.

CONCLUSIONS

ICU patients who required CRRT had increased prevalence of pulmonary hypertension and right and left ventricular systolic dysfunction. Prediction of adverse outcomes with echocardiographic parameters in this patient population can lead to identification of modifiable risk factors.

Doppler-defined pulmonary hypertension in sepsis and septic shock

BACKGROUND

The association of pulmonary hypertension (PH) in patients with sepsis is lesser understood.

METHODS

This was a retrospective study of adult patients admitted to the intensive care unit during 2007-2014 for sepsis and septic shock, with echocardiography performed <72 h. PH was defined as tricuspid regurgitation peak velocity (TRV) > 3 m/s on Doppler echocardiography. Patients with prior PH, pulmonary stenosis, or without measurable TRV were excluded. Outcomes included 28-day mortality, one-year survival and length of stay.

RESULTS

Eighty-three, of 241 (34.4%) patients included, had PH. Patients with PH were older and had greater cardiovascular comorbidity but similar illness severity, including acute respiratory distress syndrome and mechanical ventilation use. PH was an independent predictor of 28-day mortality (odds ratio 3.6 [95% confidence interval 1.1-12.5] p = .04). In a proportional hazards model, PH was an independent predictor of one-year survival (hazard ratio 1.7 [95% confidence interval 1.1-2.7]; p = .03). Severity of PH was associated with worse one-year survival but not 28-day mortality.

CONCLUSIONS

In patients with sepsis and septic shock, PH is common and is noted to be associated with higher short and long-term mortality. Further studies are needed to understand the mechanisms by which PH is associated with outcomes.

Organic mononitrites of 1,2-propanediol act as an effective NO-releasing vasodilator in pulmonary hypertension and exhibit no cross-tolerance with nitroglycerin in anesthetized pigs

Purpose

Clinically available intravenous (IV) nitric oxide (NO) donor drugs such as nitroglycerin (GTN) cause systemic hypotension and/or tolerance development. In a porcine model, novel NO donor compounds – the organic mononitrites of 1,2-propanediol (PDNO) – were compared to GTN with regard to pulmonary selectivity and tolerance development. The vasodilatory effects of inorganic nitrite were investigated.

Materials and methods

In anesthetized piglets, central hemodynamics were monitored. At normal pulmonary vascular resistance (PVR), IV infusions of PDNO (15–60 nmol kg⁻¹ min⁻¹), GTN (13–132 nmol kg⁻¹ min⁻¹), and inorganic nitrite (dosed as PDNO) were administered. At increased PVR (by U46619 IV), IV infusions of PDNO (60–240 nmol kg⁻¹ min⁻¹) and GTN (75–300 nmol kg⁻¹ min⁻¹) before and after a 5 h infusion of GTN (45 nmol kg⁻¹ min⁻¹) were given.

Results

At normal PVR, PDNO (n=12) and GTN (n=7) caused significant dose-dependent decreases in mean systemic and pulmonary arterial pressures, whereas inorganic nitrite (n=13) had no significant effect. At increased PVR, PDNO (n=6) and GTN (n=6) significantly decreased mean systemic and pulmonary pressures and resistances, but only PDNO reduced the ratio between pulmonary and systemic vascular resistances significantly. After the 5 h GTN infusion, the hemodynamic response to GTN infusions (n=6) was significantly suppressed, whereas PDNO (n=6) produced similar hemodynamic effects to those observed before the GTN infusion.

Conclusion

PDNO is a vasodilator with selectivity for pulmonary circulation exhibiting no cross-tolerance to GTN, but GTN causes non selective vasodilatation with substantial tolerance development in the pulmonary and systemic circulations. Inorganic nitrite has no vasodilatory properties at relevant doses.

Pulmonary Hypertension in the Intensive Care Unit

Pulmonary hypertension occurs as the result of disease processes increasing pressure within the pulmonary circulation, eventually leading to right ventricular failure. Patients may become critically ill from complications of pulmonary hypertension and right ventricular failure or may develop pulmonary hypertension as the result of critical illness. Diagnostic testing should evaluate for common causes such as left heart failure, hypoxemic lung disease and pulmonary embolism. Relatively few patients with pulmonary hypertension encountered in clinical practice require specific pharmacologic treatment of pulmonary hypertension targeting the pulmonary vasculature. Management of right ventricular failure involves optimization of preload, maintenance of systemic blood pressure and augmentation of inotropy to restore systemic perfusion. Selected patients may require pharmacologic therapy to reduce right ventricular afterload by directly targeting the pulmonary vasculature, but only after excluding elevated left heart filling pressures and confirming increased pulmonary vascular resistance. Critically-ill patients with pulmonary hypertension remain at high risk of adverse outcomes, requiring a diligent and thoughtful approach to diagnosis and treatment.

Nox2-dependent glutathionylation of endothelial NOS leads to uncoupled superoxide production and endothelial barrier dysfunction in acute lung injury

Microvascular barrier integrity is dependent on bioavailable nitric oxide (NO) produced locally by endothelial NO synthase (eNOS). Under conditions of limited substrate or cofactor availability or by enzymatic modification, eNOS may become uncoupled, producing superoxide in lieu of NO. This study was designed to investigate how eNOS-dependent superoxide production contributes to endothelial barrier dysfunction in inflammatory lung injury and its regulation. C57BL/6J mice were challenged with intratracheal LPS. Bronchoalveolar lavage fluid was analyzed for protein accumulation, and lung tissue homogenate was assayed for endothelial NOS content and function. Human lung microvascular endothelial cell (HLMVEC) monolayers were exposed to LPS in vitro, and barrier integrity and superoxide production were measured. Biopterin species were quantified, and coimmunoprecipitation (Co-IP) assays were performed to identify protein interactions with eNOS that putatively drive uncoupling. Mice exposed to LPS demonstrated eNOS-dependent increased alveolar permeability without evidence for altered canonical NO signaling. LPS-induced superoxide production and permeability in HLMVEC were inhibited by the NOS inhibitor nitro-l-arginine methyl ester, eNOS-targeted siRNA, the eNOS cofactor tetrahydrobiopterin, and superoxide dismutase. Co-IP indicated that LPS stimulated the association of eNOS with NADPH oxidase 2 (Nox2), which correlated with augmented eNOS S-glutathionylation both in vitro and in vivo. In vitro, Nox2-specific inhibition prevented LPS-induced eNOS modification and increases in both superoxide production and permeability. These data indicate that eNOS uncoupling contributes to superoxide production and barrier dysfunction in the lung microvasculature after exposure to LPS. Furthermore, the results implicate Nox2-mediated eNOS-S-glutathionylation as a mechanism underlying LPS-induced eNOS uncoupling in the lung microvasculature.