Pulmonary hypertension in critical care

Pulmonary Hypertension-Associated Right Ventricular Cardiomyocyte Remodelling Reduces Treprostinil Function

(1) Pulmonary hypertension (PH)-associated right ventricular (RV) failure is linked to a reduction in pulmonary vasodilators. Treprostinil has shown effectiveness in PAH patients with cardiac decompensation, hinting at potential cardiac benefits. We investigated treprostinil's synergy with isoprenaline in RV and LV cardiomyocytes. We hypothesised that disease-related RV structural changes in cardiomyocytes would reduce contractile responses and cAMP/PKA signalling activity. (2) We induced PH in male Sprague Dawley rats using monocrotaline and isolated their ventricular cardiomyocytes. The effect of in vitro treprostinil and isoprenaline stimulation on contraction was assessed. FRET microscopy was used to study PKA activity associated with treprostinil stimulation in AKAR3-NES FRET-based biosensor-expressing cells. (3) RV cells exhibited maladaptive remodelling with hypertrophy, impaired contractility, and calcium transients compared to control and LV cardiomyocytes. Combining treprostinil and isoprenaline failed to enhance inotropy in PH RV cardiomyocytes. PH RV cardiomyocytes displayed an aberrant contractile behaviour, which the combination treatment could not rectify. Finally, we observed decreased PKA activity in treprostinil-treated PH RV cardiomyocytes. (4) PH-associated RV cardiomyocyte remodelling reduced treprostinil sensitivity, inotropic support, and impaired relaxation. Overall, this study highlights the complexity of RV dysfunction in advanced PH and suggests the need for alternative therapeutic strategies.

Management of Post-Myocardial Infarction Right Ventricular Failure

Right ventricular failure (RVF) due to an acute myocardial infarction (MI) has been associated with high morbidity and mortality. Initial treatment is guided by early recognition and prompt revascularization. Current management of post-MI RVF is built upon expert consensus and is also informed by RVF from other etiologies, including massive pulmonary embolism, left ventricular assist device-associated right ventricular dysfunction, postcardiotomy shock, etc.; this speaks to the limited data available on the specific management of RVF in acute MI. The goal of this review is to discuss the current literature on the pathophysiology, general management considerations, interventional management, hemodynamic monitoring, medical management, and mechanical circulatory support of MI-induced RVF.

Determination and pharmacokinetic study of riociguat by UPLC-MS/MS in human plasma

Pulmonary hypertension (PH) is frequent in the general population and is linked to an increased risk of death. Riociguat is a kind of endothelin receptor antagonist that is often used to treat PH. For pharmacokinetic studies and the determination of riociguat in PH patients, a new, quick, easy, and sensitive UPLC-MS/MS approach was designed and validated. Riociguat and irbesartan (IS) were detected using ESI in positive ion and multiple reaction monitoring mode, respectively, by monitoring the mass transitions m/z 423.0 → 391.0 and 429.1 → 206.9. A reverse-phase C18 column (5 μm, 4.6 × 150 mm) was used with an isocratic mobile phase of water containing 0.1 % formic acid-acetonitrile (25:75, v/v) at a flow rate of 1 ml/min for chromatographic separation. In the range of 5-400 ng/ml, the calibration curve was linear and had a good correlation coefficient (0.9972). This is the first UPLC-MS/MS technique that has been developed and validated for determining riociguat from human plasma. The developed analytical method was extensively validated for linearity, selectivity, specificity, accuracy, precision, sensitivity, stability, matrix effect and recovery, according to FDA criteria. The devised approach was successfully used for a pharmacokinetic research and riociguat determination in PH patients.

Considerations for Inotrope and Vasopressor Use in Critically Ill Patients With Pulmonary Arterial Hypertension

ABSTRACT

Pulmonary arterial hypertension (PAH) is a rare and progressive cardiopulmonary disease, characterized by pulmonary vasculopathy. The disease can lead to increase pulmonary arterial pressures and eventual right ventricle failure due to elevated afterload. The prevalence of PAH in patients admitted to the intensive care unit (ICU) is unknown, and pulmonary hypertension (PH) in the ICU is more commonly the result of left heart disease or hypoxic lung injury (PH due to left heart disease and PH due to lung diseases and/or hypoxia, respectively), as opposed to PAH. Management of patients with PAH in the ICU is complex as it requires a careful balance to maintain perfusion while optimizing right-sided heart function. A comprehensive understanding of the underlying physiology and underlying hemodynamics is crucial for the management of this population. In this review, we summarized the evidence for use of vasopressors and inotropes in the management of PH and extrapolated the data to patients with PAH. We strongly believe that the understanding of the hemodynamic consequences of inotropes and vasopressors, especially from data in the PH population, can lead to better management of this complex patient population.

Pulmonary Hypertension in Pregnancy: A Review

Pulmonary hypertension (PH) is a disease, which targets the pulmonary vasculature affecting the heart and the lungs, and is characterized by a vast array of signs and symptoms. These manifestations of PH in pregnancy are highly variable and non-specific hence, it is prudent to have a very keen and high index of suspicion while evaluating these patients. This rare disease can be extremely debilitating and can be associated with a poor overall prognosis. Pregnancy in women with PH puts them at an elevated risk because the physiological changes associated with pregnancy are not well endured leading to even higher morbidity and mortality in these patients. Although there are various modalities for evaluation and workup of PH, right heart catheterization (RHC) remains the gold standard. A mean pulmonary artery pressure (PAP) of more than 20 mm of Hg is considered diagnostic. It is indeed heartening to see that in the past decade many novel therapeutic modalities have emerged and along with a better understanding of the disease process have proved to be promising in terms of reducing the adverse outcomes and preventing death in this population of patients.

The contemporary pulmonary artery catheter. Part 2: measurements, limitations, and clinical applications

Nowadays, the classical pulmonary artery catheter (PAC) has an almost 50-year-old history of its clinical use for hemodynamic monitoring. In recent years, the PAC evolved from a device that enabled intermittent cardiac output measurements in combination with static pressures to a monitoring tool that provides continuous data on cardiac output, oxygen supply and-demand balance, as well as right ventricular performance. In this review, which consists of two parts, we will introduce the difference between intermittent pulmonary artery thermodilution using bolus injections, and the contemporary PAC enabling continuous measurements by using a thermal filament which heats up the blood. In this second part, we will discuss in detail the measurements of the contemporary PAC, including continuous cardiac output measurement, right ventricular ejection fraction, end-diastolic volume index, and mixed venous oxygen saturation. Limitations of all of these measurements are highlighted as well. We conclude that thorough understanding of measurements obtained from the PAC is the first step in successful application of the PAC in daily clinical practice.

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.

Acute Right Ventricular Dysfunction in Intensive Care Unit

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.

Management of acute subdural hematoma in a patient with portopulmonary hypertension on prostanoid therapy

Background:

Treprostinil is a prostacyclin analog used to treat portopulmonary hypertension (PPHTN) and is one of several drugs shown to increase survival, but results in platelet dysfunction. Little is known about the management of patients on treprostinil who present with an acute subdural hematoma (aSDH). We describe such a case and offer our recommendations on management based on our experience and review of the literature.

Case Description:

A 63-year-old, right-handed female with a history of PPHTN presented with severe headache and was found to have a large left aSDH with midline shift on imaging. She was admitted to the neurosurgical intensive care unit (ICU) where she developed hemiparesis and subsequently underwent emergent decompression. Postoperatively she improved, but several hours after became obtunded and imaging showed reaccumulation of the aSDH, which required reoperation. At 6 months postoperatively she had only a mild hemiparesis and was being reconsidered for treprostinil therapy as a bridge to liver transplant. Only one paper in the literature thus far has reported a patient with an aSDH managed with treprostinil. The authors achieved adequate intraoperative hemostasis without the use of platelet transfusion and lack of complications intraoperatively.

Conclusion:

While concerns related to the risk of bleeding in surgery are valid, intraoperative hemostasis does not appear to be profoundly affected. Surgical intervention should not be delayed and prostanoid therapy discontinued, if possible, postoperatively. Patients should be placed in an intensive care setting with assistance from pulmonary specialists and close monitoring of neurological status and blood pressure.

Aerosolized Vasodilators for the Treatment of Pulmonary Hypertension in Cardiac Surgical Patients: A Systematic Review and Meta-analysis

BACKGROUND

In cardiac surgery, pulmonary hypertension is an important prognostic factor for which several treatments have been suggested over time. In this systematic review and meta-analysis, we compared the efficacy of inhaled aerosolized vasodilators to intravenously administered agents and to placebo in the treatment of pulmonary hypertension during cardiac surgery. We searched MEDLINE, CENTRAL, EMBASE, Web of Science, and clinicaltrials.gov databases from inception to October 2015. The incidence of mortality was assessed as the primary outcome. Secondary outcomes included length of stay in hospital and in the intensive care unit, and evaluation of the hemodynamic profile.

METHODS

Of the 2897 citations identified, 10 studies were included comprising a total of 434 patients.

RESULTS

Inhaled aerosolized agents were associated with a significant decrease in pulmonary vascular resistance (-41.36 dyne·s/cm, P= .03) and a significant increase in mean arterial pressure (8.24 mm Hg, P= .02) and right ventricular ejection fraction (7.29%, P< .0001) when compared to intravenously administered agents. No significant hemodynamically meaningful differences were observed between inhaled agents and placebo; however, an increase in length of stay in the intensive care unit was shown with the use of inhaled aerosolized agents (0.66 days, P= .01). No other differences were observed for either comparison.

CONCLUSIONS

The administration of inhaled aerosolized vasodilators for the treatment of pulmonary hypertension during cardiac surgery is associated with improved right ventricular performance when compared to intravenously administered agents. This review does not support any benefit compared to placebo on major outcomes. Further investigation is warranted in this area of research and should focus on clinically significant outcomes.

Management of right heart failure in the critically ill

Right ventricular failure complicates several commonly encountered conditions in the intensive care unit. Right ventricular dilation and paradoxic movement of the interventricular septum on echocardiography establishes the diagnosis. Right heart catheterization is useful in establishing the specific cause and aids clinicians in management. Principles of treatment focus on reversal of the underlying cause, optimization of right ventricular preload and contractility, and reduction of right ventricular afterload. Mechanical support with right ventricular assist device or veno-arterial extracorporeal membrane oxygenation can be used in select patients who fail to improve with optimal medical therapy.

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.

Inhaled nitric oxide therapy and risk of renal dysfunction: a systematic review and meta-analysis of randomized trials

INTRODUCTION

Inhaled nitric oxide (iNO) is an important therapy for acute respiratory distress syndrome (ARDS), pulmonary hypertension and pediatric hypoxemic respiratory failure. Safety concerns regarding iNO and renal dysfunction have been reported; however, there are currently no systematic reviews on this issue. Our objective was to evaluate published randomized controlled trials (RCTs) to ascertain the risk of renal dysfunction associated with iNO therapy in patients with and without ARDS.

METHODS

A systematic review of databases was performed to identify RCTs which compared iNO with controls up to September 2014. Effect estimates for risk ratio (RR) of acute kidney injury (AKI) were pooled using a random-effects model.

RESULTS

Ten RCTs involving 1363 participants were included. Inhaled nitric oxide significantly increased the risk of AKI compared with controls (RR, 1.4, 95%CI, 1.06 to 1.83, p = 0.02). In the stratified analysis, a high cumulative-dose of iNO significantly increased the risk of AKI (RR, 1.52, 95%CI, 1.14 to 2.02, p = 0.004), whereas medium and low cumulative-doses did not (RR, 0.64, 95%CI, 0.23 to 1.81 and RR, 0.56, 95%CI, 0.11 to 2.86 respectively). In subgroup analysis by study population, an increased risk of AKI was observed in patients with ARDS (RR, 1.55, 95%CI, 1.15 to 2.09, p = 0.005) but not in those without (RR, 0.90, 95%CI, 0.49 to 1.67, p = 0.75).

CONCLUSIONS

The available data show that iNO therapy may increase the risk of renal dysfunction, especially with prolonged use and in patients with ARDS. The risk in pediatric population is unknown owing to limited data. We suggest monitoring renal function during iNO therapy, and that future trials of iNO should evaluate renal safety.

Pulmonary arterial hypertension in pregnancy

Pulmonary hypertension is a medical condition characterized by elevated pulmonary arterial pressure and secondary right heart failure. Pulmonary arterial hypertension is a subset of pulmonary hypertension, which is characterized by an underlying disorder of the pulmonary arterial vasculature. Pulmonary hypertension can also occur secondarily to structural cardiac disease, autoimmune disorders, and toxic exposures. Although pregnancies affected by pulmonary hypertension and pulmonary arterial hypertension are rare, the pathophysiology exacerbated by pregnancy confers both high maternal and fetal mortality and morbidity. In light of new treatment modalities and the use of a multidisciplinary approach to care, maternal outcomes may be improving.

Pulmonary hypertension in pregnancy: critical care management

Pulmonary hypertension is common in critical care settings and in presence of right ventricular failure is challenging to manage. Pulmonary hypertension in pregnant patients carries a high mortality rates between 30-56%. In the past decade, new treatments for pulmonary hypertension have emerged. Their application in pregnant women with pulmonary hypertension may hold promise in reducing morbidity and mortality. Signs and symptoms of pulmonary hypertension are nonspecific in pregnant women. Imaging workup may have undesirable radiation exposure. Pulmonary artery catheter remains the gold standard for diagnosing pulmonary hypertension, although its use in the intensive care unit for other conditions has slowly fallen out of favor. Goal-directed bedside echocardiogram and lung ultrasonography provide attractive alternatives. Basic principles of managing pulmonary hypertension with right ventricular failure are maintaining right ventricular function and reducing pulmonary vascular resistance. Fluid resuscitation and various vasopressors are used with caution. Pulmonary-hypertension-targeted therapies have been utilized in pregnant women with understanding of their safety profile. Mainstay therapy for pulmonary embolism is anticoagulation, and the treatment for amniotic fluid embolism remains supportive care. Multidisciplinary team approach is crucial to achieving successful outcomes in these difficult cases.