Effects of levosimendan on acute pulmonary embolism-induced right ventricular failure*

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 (ECMO) 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 ECMO cannulation should be implemented early if ongoing deterioration occurs despite these interventions.

Immediate cardiopulmonary responses to consecutive pulmonary embolism: a randomized, controlled, experimental study

BACKGROUND

Acute pulmonary embolism (PE) induces ventilation-perfusion mismatch and hypoxia and increases pulmonary pressure and right ventricular (RV) afterload, entailing potentially fatal RV failure within a short timeframe. Cardiopulmonary factors may respond differently to increased clot burden. We aimed to elucidate immediate cardiopulmonary responses during successive PE episodes in a porcine model.

METHODS

This was a randomized, controlled, blinded study of repeated measurements. Twelve pigs were randomly assigned to receive sham procedures or consecutive PEs every 15 min until doubling of mean pulmonary pressure. Cardiopulmonary assessments were conducted at 1, 2, 5, and 13 min after each PE using pressure-volume loops, invasive pressures, and arterial and mixed venous blood gas analyses. ANOVA and mixed-model statistical analyses were applied.

RESULTS

Pulmonary pressures increased after the initial PE administration (p < 0.0001), with a higher pulmonary pressure change compared to pressure change observed after the following PEs. Conversely, RV arterial elastance and pulmonary vascular resistance was not increased after the first PE, but after three PEs an increase was observed (p = 0.0103 and p = 0.0015, respectively). RV dilatation occurred following initial PEs, while RV ejection fraction declined after the third PE (p = 0.004). RV coupling exhibited a decreasing trend from the first PE (p = 0.095), despite increased mechanical work (p = 0.003). Ventilatory variables displayed more incremental changes with successive PEs.

CONCLUSION

In an experimental model of consecutive PE, RV afterload elevation and dysfunction manifested after the third PE, in contrast to pulmonary pressure that increased after the first PE. Ventilatory variables exhibited a more direct association with clot burden.

Pressure Overload and Right Ventricular Failure: From Pathophysiology to Treatment

Right ventricular failure (RVF) is often caused by increased afterload and disrupted coupling between the right ventricle (RV) and the pulmonary arteries (PAs). After a phase of adaptive hypertrophy, pressure-overloaded RVs evolve towards maladaptive hypertrophy and finally ventricular dilatation, with reduced stroke volume and systemic congestion. In this article, we review the concept of RV-PA coupling, which depicts the interaction between RV contractility and afterload, as well as the invasive and non-invasive techniques for its assessment. The current principles of RVF management based on pathophysiology and underlying etiology are subsequently discussed. Treatment strategies remain a challenge and range from fluid management and afterload reduction in moderate RVF to vasopressor therapy, inotropic support and, occasionally, mechanical circulatory support in severe RVF.

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.

Effect of Levosimendan on Acute Decompensated Right Heart Failure in Patients With Connective Tissue Disease-Associated Pulmonary Arterial Hypertension

Aims

Acute decompensated right heart failure (RHF) in chronic precapillary pulmonary hypertension is often typified by a swiftly progressive syndrome involving systemic congestion. This results from the impairment of the right ventricular filling and/or a reduction in the flow output of the right ventricle, which has been linked to a dismal prognosis of short duration. Despite this, there are limited therapeutic data regarding these acute incidents. This study examined the effect of levosimendan on acute decompensated RHF in patients with connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH).

Methods

This retrospective study included 87 patients with confirmed CTD-PAH complicated acute decompensated RHF between November 2015 and April 2021. We collected biological, clinical, and demographic data, as well as therapy data, from patients with acute decompensated RHF who required levosimendan treatment in the cardiac care unit (CCU) for CTD-PAH. The patients were divided into two groups according to the levosimendan treatment. Patient information between the two groups was systematically compared in hospital and at follow-up.

Results

Oxygen saturation of mixed venose blood (SvO₂), estimated glomerular filtration rate (eGFR), 24-h urine output, and tricuspid annular plane systolic excursion (TAPSE) were found to be considerably elevated in the levosimendan cohort compared with the control cohort. Patients in the levosimendan cohort exhibited considerably reduced levels of C-reactive protein (CRP), white blood cell (WBC), troponin I, creatinine, NT-proBNP, and RV diameter compared with those in the control cohort. A higher survival rate was observed in the levosimendan cohort.

Conclusions

Levosimendan treatment could effectively improve acute decompensated RHF and systemic hemodynamics in CTD-PAH patients, with positive effects on survival in hospital and can, therefore, be considered as an alternative treatment option for improving clinical short-term outcomes.

Echocardiographic findings in patients with acute pulmonary embolism at Sohag University Hospitals

Background

Acute pulmonary thromboembolism (PTE) is one of the serious medical issues with higher prevalence and mortality rates. As mentioned in several medical reports, most of the chest pain patients, visiting the emergency departments, are usually diagnosed with either acute PTE, acute coronary syndromes, or acute aortic syndromes. The current study aimed to study the risk factors and explore the echocardiographic findings in patients with PTE.

Results

Forty patients with acute pulmonary embolism were enrolled in the study. Echocardiography and computed tomography pulmonary angiography (CTPA) were evaluated for all participants. The echocardiography showed that 29 patients (72.5%) had echocardiographic findings suggestive of acute PTE. Twenty-four patients (60%) had tricuspid regurge. Twenty-one patients (52.5%) had dilated right ventricle (RV). Also, 13 patients (32.5%) had an echocardiographic finding of pulmonary hypertension. Furthermore, ten patients (25%) had McConnell’s sign, and 21 patients (52.5%) had RV systolic dysfunction where only two (5%) showed RV thrombosis. Echocardiographic data of the eight high-risk patients showed that 6 patients (75%) had TR, 8 patients (100%) had dilated RV, 5 patients (62.5%) had pulmonary hypertension, 8 patients (100%) had McConnell’s sign, one patient (12.5%) had RV thrombus, and 8 patients (100%) had RV systolic dysfunction.

Conclusion

The results revealed that thrombus in the main pulmonary trunk was a high-risk factor for patients with acute pulmonary embolism. The current study suggested that echocardiography is an important bedside imaging tool for the diagnosis of PTE. Echocardiography could detect the tricuspid regurge, pulmonary hypertension, McConnell’s sign, RV dilatation, thrombosis, and dysfunction. Furthermore, echocardiography was considered a non-invasive test for rapid diagnosis of PTE and determining the degree of the risk category (high- or low-risk patients) specially with the presence of McConnell’s sign, dilated RV, and RV systolic dysfunction.

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.

Levosimendan versus dobutamine for sepsis-induced cardiac dysfunction: a systematic review and meta-analysis

Levosimendan and dobutamine are extensively used to treat sepsis-associated cardiovascular failure in ICU. Nevertheless, the role and mechanism of levosimendan in patients with sepsis-induced cardiomyopathy remains unclear. Moreover, previous studies on whether levosimendan is superior to dobutamine are still controversial. More importantly, these studies did not take changes (before-after comparison to the baseline) in quantitative parameters such as ejection fraction into account with the baseline level. Here, we aimed to determine the pros and cons of the two medicines by assessing the changes in cardiac function and blood lactate, mortality, with the standardized mean difference used as a summary statistic. Relevant studies were obtained by a thorough and disciplined literature search in several notable academic databases, including Google Scholar, PubMed, Cochrane Library and Embase until November 2020. Outcomes included changes in cardiac function, lactic acid, mortality and length of hospital stay. A total of 6 randomized controlled trials were included in this study, including 192 patients. Compared with dobutamine, patients treated with levosimendan had a greater improvement of cardiac index (ΔCI) (random effects, SMD = 0.90 [0.20,1.60]; I2 = 76%, P < 0.01) and left ventricular stroke work index (ΔLVSWI) (random effects, SMD = 1.56 [0.90,2.21]; I2 = 65%, P = 0.04), a significant decrease of blood lactate (Δblood lactate) (random effects, MD =  - 0.79 [- 1.33, - 0.25]; I2 = 68%, P < 0.01) at 24-h after drug intervention, respectively. There was no significant difference between levosimendan and dobutamine on all-cause mortality in ICU (fixed effect, OR = 0.72 [0.39,1.33]; I2 = 0%, P = 0.99). We combine effect sizes related to different measurement parameters to evaluate cardiac function, which implied that septic patients with myocardial dysfunction might have a better improvement of cardiac function by levosimendan than dobutamine (random effects, SMD = 1.05 [0.69,1.41]; I2 = 67%, P < 0.01). This study suggested a significant improvement of CI, LVSWI, and decrease of blood lactate in septic patients with myocardial dysfunction in ICU after 24-h administration of levosimendan than dobutamine. However, the administration of levosimendan has neither an impact on mortality nor LVEF. Septic patients with myocardial dysfunction may partly benefit from levosimendan than dobutamine, mainly embodied in cardiac function improvement.

Levosimendan, milrinone, and dobutamine in experimental acute pulmonary embolism

Acute pulmonary embolism is a frequent condition in emergency medicine and potentially fatal. Cause of death is right ventricular failure due to increased right ventricular afterload from both pulmonary vascular obstruction and vasoconstriction. Inodilators are interesting drugs of choice as they may improve right ventricular function and lower its afterload. We aimed to investigate the cardiovascular effects of three clinically relevant inodilators: levosimendan, milrinone, and dobutamine in acute pulmonary embolism. We conducted a randomized, blinded, animal study using 18 female pigs. Animals received large autologous pulmonary embolism until doubling of baseline mean pulmonary arterial pressure and were randomized to increasing doses of each inodilator. Effects were evaluated with bi-ventricular pressure–volume loop recordings, right heart catheterization, and blood gas analyses. Induction of pulmonary embolism increased right ventricular afterload and pulmonary pressure (p < 0.05) causing right ventricular dysfunction. Levosimendan and milrinone showed beneficial hemodynamic profiles by lowering right ventricular pressures and volume (p < 0.001) and improved right ventricular function and cardiac output (p < 0.05) without increasing right ventricular mechanical work. Dobutamine increased right ventricular pressure and function (p < 0.01) but at a cost of increased mechanical work at the highest doses, showing an adverse hemodynamic profile. In a porcine model of acute pulmonary embolism, levosimendan and milrinone reduced right ventricular afterload and improved right ventricular function, whereas dobutamine at higher doses increased right ventricular afterload and right ventricular mechanical work. The study motivates clinical testing of inodilators in patients with acute pulmonary embolism and right ventricular dysfunction.

Right ventricular adaptation in the critical phase after acute intermediate-risk pulmonary embolism

BACKGROUND

The haemodynamic response following acute, intermediate-risk pulmonary embolism is not well described. We aimed to describe the cardiovascular changes in the initial, critical phase 0-12 hours after acute pulmonary embolism in an in-vivo porcine model.

METHODS

Pigs were randomly allocated to pulmonary embolism (n = 6) or sham (n = 6). Pulmonary embolism was administered as autologous blood clots (20 × 1 cm) until doubling of mean pulmonary arterial pressure or mean pulmonary arterial pressure was greater than 34 mmHg. Sham animals received saline. Cardiopulmonary changes were evaluated for 12 hours after intervention by biventricular pressure-volume loop recordings, invasive pressure measurements, arterial and central venous blood gas analyses.

RESULTS

Mean pulmonary arterial pressure increased (P < 0.0001) and stayed elevated for 12 hours in the pulmonary embolism group compared to sham. Pulmonary vascular resistance and right ventricular arterial elastance (right ventricular afterload) were increased in the first 11 and 6 hours, respectively, after pulmonary embolism (P < 0.01 for both) compared to sham. Right ventricular ejection fraction was reduced (P < 0.01) for 8 hours, whereas a near-significant reduction in right ventricular stroke volume was observed (P = 0.06) for 4 hours in the pulmonary embolism group compared to sham. Right ventricular ventriculo-arterial coupling was reduced (P < 0.05) for 6 hours following acute pulmonary embolism despite increased right ventricular mechanical work in the pulmonary embolism group (P < 0.01) suggesting right ventricular failure.

CONCLUSIONS

In a porcine model of intermediate-risk pulmonary embolism, the increased right ventricular afterload caused initial right ventricular ventriculo-arterial uncoupling and dysfunction. After approximately 6 hours, the right ventricular afterload returned to pre-pulmonary embolism values and right ventricular function improved despite a sustained high pulmonary arterial pressure. These results suggest an initial critical and vulnerable phase of acute pulmonary embolism before haemodynamic adaptation.

Levosimendan in the light of the results of the recent randomized controlled trials: an expert opinion paper

Despite interesting and unique pharmacological properties, levosimendan has not proven a clear superiority to placebo in the patient populations that have been enrolled in the various recent multicenter randomized controlled trials. However, the pharmacodynamic effects of levosimendan are still considered potentially very useful in a number of specific situations.Patients with decompensated heart failure requiring inotropic support and receiving beta-blockers represent the most widely accepted indication. Repeated infusions of levosimendan are increasingly used to facilitate weaning from dobutamine and avoid prolonged hospitalizations in patients with end-stage heart failure, awaiting heart transplantation or left ventricular assist device implantation. New trials are under way to confirm or refute the potential usefulness of levosimendan to facilitate weaning from veno-arterial ECMO, to treat cardiogenic shock due to left or right ventricular failure because the current evidence is mostly retrospective and requires confirmation with better-designed studies. Takotsubo syndrome may represent an ideal target for this non-adrenergic inotrope, but this statement also relies on expert opinion. There is no benefit from levosimendan in patients with septic shock. The two large trials evaluating the prophylactic administration of levosimendan (pharmacological preconditioning) in cardiac surgical patients with poor left ventricular ejection fraction could not show a significant reduction in their composite endpoints reflecting low cardiac output syndrome with respect to placebo. However, the subgroup of those who underwent isolated CABG appeared to have a reduction in mortality. A new study will be required to confirm this exploratory finding.Levosimendan remains a potentially useful inodilator agent in a number of specific situations due to its unique pharmacological properties. More studies are needed to provide a higher level of proof regarding these indications.

Intensive care, right ventricular support and lung transplantation in patients with pulmonary hypertension

Intensive care of patients with pulmonary hypertension (PH) and right-sided heart failure includes treatment of factors causing or contributing to heart failure, careful fluid management, and strategies to reduce ventricular afterload and improve cardiac function. Extracorporeal membrane oxygenation (ECMO) should be considered in distinct situations, especially in candidates for lung transplantation (bridge to transplant) or, occasionally, in patients with a reversible cause of right-sided heart failure (bridge to recovery). ECMO should not be used in patients with end-stage disease without a realistic chance for recovery or for transplantation. For patients with refractory disease, lung transplantation remains an important treatment option. Patients should be referred to a transplant centre when they remain in an intermediate- or high-risk category despite receiving optimised pulmonary arterial hypertension therapy. Meticulous peri-operative management including the intra-operative and post-operative use of ECMO effectively prevents graft failure. In experienced centres, the 1-year survival rates after lung transplantation for PH now exceed 90%.

Prise en charge de l'embolie pulmonaire grave en réanimation

L'embolie pulmonaire (EP) grave, définie par la présence d’un état de choc, est à l'origine d'une mortalité importante. L'objectif de cette mise au point est de synthétiser les dernières avancées et recommandations concernant la prise en charge des formes graves d'EP. La stratification du risque individuel de mortalité précoce permet d'apporter une stratégie diagnostique et thérapeutique optimisée pour chaque patient. Le traitement symptomatique consiste essentiellement en la prise en charge de l'état de choc. L'anticoagulation curative par héparine non fractionnée est réservée aux patients hémodynamiquement instables. Chez ces patients à haut risque, la thrombolyse systémique diminue la mortalité et le risque de récidive d'EP. Chez les patients à risque intermédiaire élevé, la thrombolyse systémique à dose standard diminue le risque de choc secondaire mais sans impact sur la mortalité globale. La thrombolyse est donc réservée aux patients à risque intermédiaire élevé présentant secondairement un état de choc. L'embolectomie chirurgicale reste indiquée en cas de contre-indication absolue à la thrombolyse ou en cas d'échec de celle-ci. Le positionnement dans l'algorithme thérapeutique de l'assistance extracorporelle et des techniques percutanées de revascularisation reste à définir. Leurs indications doivent donc être discutées dans des centres experts après une concertation multidisciplinaire incluant pneumologues, cardiologues, réanimateurs, radiologues interventionnels et chirurgiens cardiaques.

Right Ventricular-Pulmonary Vascular Interactions

Accurate and comprehensive evaluation of right ventricular (RV)-pulmonary vascular (PV) interactions is critical to the assessment of cardiopulmonary function, dysfunction, and failure. Here, we review methods of quantifying RV-PV interactions and experimental results from clinical trials as well as large- and small-animal models based on pressure-volume analysis. We conclude by outlining critical gaps in knowledge that should drive future studies.

Levosimendan in pulmonary hypertension and right heart failure

Pulmonary hypertension is a multifactorial disease with a high morbidity and mortality. Right ventricular function is the most important predictor of morbidity and mortality in patients suffering from pulmonary hypertension, but currently there are no approved treatments directly supporting the failing right ventricle. Levosimendan is a calcium sensitizing agent with inotropic, pulmonary vasodilatory, and cardioprotective properties. Given its pharmacodynamic profile, levosimendan could be a potential novel agent for the treatment of right ventricular failure caused by pulmonary hypertension. The aim of this review is to provide an overview of the current knowledge on the effects of levosimendan in pulmonary hypertension and right heart failure.

Hospital and intensive care unit management of decompensated pulmonary hypertension and right ventricular failure

Pulmonary hypertension and concomitant right ventricular failure present a diagnostic and therapeutic challenge in the intensive care unit and have been associated with a high mortality. Significant co-morbidities and hemodynamic instability are often present, and routine critical care unit resuscitation may worsen hemodynamics and limit the chances of survival in patients with an already underlying poor prognosis. Right ventricular failure results from structural or functional processes that limit the right ventricle’s ability to maintain adequate cardiac output. It is commonly seen as the result of left heart failure, acute pulmonary embolism, progression or decompensation of pulmonary hypertension, sepsis, acute lung injury, or in the perioperative setting. Prompt recognition of the underlying cause and institution of treatment with a thorough understanding of the elements necessary to optimize preload, cardiac contractility, enhance systemic arterial perfusion, and reduce right ventricular afterload are of paramount importance. Moreover, the emergence of previously uncommon entities in patients with pulmonary hypertension (pregnancy, sepsis, liver disease, etc.) and the availability of modern devices to provide support pose additional challenges that must be addressed with an in-depth knowledge of this disease.

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.

Effect of levosimendan on prognosis in adult patients undergoing cardiac surgery: a meta-analysis of randomized controlled trials

Background

Small trials suggest that levosimendan is associated with a favorable outcome in patients undergoing cardiac surgery. However, recently published larger-scale trials did not provide evidence for a similar benefit from levosimendan. We performed a meta-analysis to assess the survival benefits of levosimendan in patients undergoing cardiac surgery and to investigate its effects in subgroups of patients with preoperative low-ejection fraction (EF).

Methods

We identified randomized clinical trials through 20 April 2017 that investigated levosimendan therapy versus control in patients undergoing cardiac surgery. Individual patient data from each study were compiled. Meta-analyses were performed for primary outcomes, secondary outcomes and serious adverse events, and subgroup analyses according to the preoperative EF of enrolled patients were also conducted. The risk of bias was assessed using the Cochrane risk-of-bias tool.

Results

Seventeen studies involving a total of 2756 patients were included. Levosimendan therapy was associated with a significant reduction in 30-day mortality (RR 0.67; 95% CI, 0.49 to 0.93; p = 0.02) and reduced the risk of death in single-center trials (RR 0.49; 95% CI, 0.30 to 0.79; p = 0.004) and in subgroup trials of inferior quality (RR 0.39; 95% CI, 0.17 to 0.92; p = 0.02); however, in multicenter and in high-quality subgroup-analysis trials, no significant difference in mortality was observed between patients who received levosimendan therapy and controls (p > 0.05). However, in high-quality subgroup trials, levosimendan therapy was associated with reduced mortality in patients in a preoperative low-EF subgroup (RR 0.58; 95% CI, 0.38 to 0.88; p = 0.01). Similarly, only patients in the preoperative low-EF subgroup benefited in terms of reduced risk of renal replacement therapy (RR 0.54; 95% CI, 0.34 to 0.85; p = 0.007). Furthermore, levosimendan therapy was associated with a significant reduction in intensive care unit (ICU) length of stay (MDR −17.19; 95% CI, −34.43 to −2.94; p = 0.02).

Conclusions

In patients undergoing cardiac surgery, the benefit of levosimendan in terms of survival was not shown in multicenter or in high-quality trials; however, levosimendan therapy was associated with reduced mortality in patients with preoperative ventricular systolic dysfunction.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1848-1) contains supplementary material, which is available to authorized users.

Advancing knowledge of right ventricular pathophysiology in chronic pressure overload: Insights from experimental studies

The right ventricle (RV) has to face major changes in loading conditions due to cardiovascular diseases and pulmonary vascular disorders. Clinical experience supports evidence that the RV better compensates for volume than for pressure overload, and for chronic than for acute changes. For a long time, right ventricular (RV) pathophysiology has been restricted to patterns extrapolated from left heart studies. However, the two ventricles are anatomically, haemodynamically and functionally distinct. RV metabolic properties may also result in a different behaviour in response to pathological conditions compared with the left ventricle. In this review, current knowledge of RV pathophysiology is reported in the setting of chronic pressure overload, including recent experimental findings and emerging concepts. After a time-varying compensated period with preserved cardiac output despite overload conditions, RV failure finally occurs, leading to death. The underlying mechanisms involved in the transition from compensatory hypertrophy to maladaptive remodelling are not completely understood.

Acute effects of levosimendan in experimental models of right ventricular hypertrophy and failure

Pulmonary arterial hypertension (PAH) is a fatal disease, and the ultimate cause of death is right ventricular (RV) failure. In this study, we investigated the acute hemodynamic effects of levosimendan in two rat models of RV hypertrophy and failure. Wistar rats were randomized to receive sham surgery (n = 8), pulmonary trunk banding (PTB; n = 8), or monocrotaline injection (MCT; n = 7). RV function was evaluated at baseline and after injection of placebo and two concentrations of levosimendan (12 and 60 μg/kg) using magnetic resonance imaging, echocardiography, and invasive pressure recordings. PTB and MCT injection caused hypertrophy, dilatation, and failure of the RV compared with sham surgery. Levosimendan increased RV end systolic pressure (sham surgery: 16.0% ± 3.8% [P = 0.0038]; MCT: 9.9% ± 3.1% [P = 0.018]; PTB: 24.5% ± 3.3% [P = 0.0001]; mean ± SEM) compared with placebo. Levosimendan markedly increased RV stroke volume (SV) in the MCT group (29.1% ± 8.3%; P = 0.012), did not change RV SV in the PTB group (0.4% ± 4.5%; P = 0.93), and decreased RV SV in the sham surgery group (-10.9% ± 3.7%; P = 0.020). Nitroprusside, which was used to mimic the systemic arterial vasodilator action of levosimendan, did not influence RV function. These data demonstrate that levosimendan acutely improves the failing right heart in a MCT model of PAH and that the mechanism involves a direct acute positive inotropic effect on the hypertrophic and failing RV of the rat.

Right ventricular adaptation to pulmonary pressure load in patients with chronic thromboembolic pulmonary hypertension before and after successful pulmonary endarterectomy--a cardiovascular magnetic resonance study

BACKGROUND

The aim of the study was to characterize RV adaptation to varying loading conditions in patients with chronic thromboembolic hypertension (CTEPH) before and after pulmonary endarterectomy (PEA). Nearly 4% of patients with pulmonary embolism develop CTEPH. PEA offers a cure with excellent outcome. By use of cardiovascular magnetic resonance (CMR) combined with hemodynamic measurements pulmonary arterial elastance (Ea-pulm_i), end-systolic right ventricular elastance (Ees-RV_i) and ventriculo-arterial coupling (Ea-pulm_i/Ees-RV_i) can be studied before and after PEA.

METHODS

Sixty-five patients (mean age 41±12 years, 28 female) underwent CMR pre- and post-PEA. Ejection fraction (EF), end-diastolic (EDVi), end-systolic (ESVi), and stroke (SVi) volumes were indexed for body surface area. Ea-pulm_i was calculated as pulmonary artery mean pressure (mPAP)/SVi, and Ees-RV_i as mPAP/ESVi.

RESULTS

mPAP decreased from 47±12 to 25±9 mmHg, p=0.0001. Ea-pulm_i was increased before PEA and normalized afterwards (2.8±2.1 vs. 0.85±0.4 mmHg/ml/m2, p=0.0001). Ees-RV_i was depressed before and after PEA (0.72±0.27 vs. 0.66±0.3 mmHg/ml/m2, p=0.13). EF improved from 25±12% to 46±10%, p=0.0001, because ventriculo-arterial coupling was restored (4.2±3 vs. 1.4±0.6, p=0.0001). EDVi and ESVi mproved significantly (EDVi 92±32 to 72±23 ml, p=0.0001; ESVi 69±31 to 41±18 ml, p=0.0001).

CONCLUSION

RV function is largely determined by afterload and returns to normal once afterload is normalized. This is paralleled by a significant improvement of CMR indices of right ventricular remodelling.

Levosimendan: The current situation and new prospects

Levosimendan is a pyridazinone-dinitrile derivative with positive inotropic and vasodilatory effects that has beneficial effects on myocardial performance. In previous randomized studies levosimendan improved hemodynamics and clinical course, but its effect on prognosis is still unclear. This important issue has limited its use. Although primarily used in the management of acute heart failure syndromes, this new inotropic agent may play a role in other clinical conditions. This review aims to summarize current knowledge on levosimendan and to present future prospects for the use of this drug.

Pulmonary vascular diseases

Diseases of the pulmonary vasculature are a cause of increased pulmonary vascular resistance (PVR) in pulmonary embolism, chronic thromboembolic pulmonary hypertension (CTEPH), and pulmonary arterial hypertension or decreased PVR in pulmonary arteriovenous malformations on hereditary hemorrhagic telangiectasia, portal hypertension, or cavopulmonary anastomosis. All these conditions are associated with a decrease in both arterial PO2 and PCO2. Gas exchange in pulmonary vascular diseases with increased PVR is characterized by a shift of ventilation and perfusion to high ventilation-perfusion ratios, a mild to moderate increase in perfusion to low ventilation-perfusion ratios, and an increased physiologic dead space. Hypoxemia in these patients is essentially explained by altered ventilation-perfusion matching amplified by a decreased mixed venous PO2 caused by a low cardiac output. Hypocapnia is accounted for by hyperventilation, which is essentially related to an increased chemosensitivity. A cardiac shunt on a patent foramen ovale may be a cause of severe hypoxemia in a proportion of patients with pulmonary hypertension and an increase in right atrial pressure. Gas exchange in pulmonary arteriovenous malformations is characterized by variable degree of pulmonary shunting and/or diffusion-perfusion imbalance. Hypocapnia is caused by an increased ventilation in relation to an increased pulmonary blood flow with direct peripheral chemoreceptor stimulation by shunted mixed venous blood flow.

Massive pulmonary embolism

Massive pulmonary embolism (PE) is a potentially lethal condition, with death usually caused by right ventricular (RV) failure and cardiogenic shock. Systemic thrombolysis (unless contraindicated) is recommended as the first-line treatment of massive PE to decrease the thromboembolic burden on the RV and increase pulmonary perfusion. Surgical pulmonary embolectomy or catheter-directed thrombectomy should be considered in patients with contraindications to fibrinolysis, or those with persistent hemodynamic compromise or RV dysfunction despite fibrinolytic therapy. Critical care management predominantly involves supporting the RV, by optimizing preload, RV contractility, and coronary perfusion pressure and minimizing afterload. Despite these interventions, mortality remains high.

Pulmonary hypertension in canine degenerative mitral valve disease

Pulmonary hypertension secondary to degenerative mitral valve disease has been recognized clinically for many years in veterinary medicine, and clinical diagnosis of this syndrome in dogs has been enhanced greatly by widespread use of echocardiography and Doppler echocardiography. Medical therapy is now available to treat this clinical complication of mitral valve disease, making timely diagnosis even more important to patient longevity and quality of life.

Intensive care unit management of patients with severe pulmonary hypertension and right heart failure

Despite advances in medical therapies, pulmonary arterial hypertension (PAH) continues to cause significant morbidity and mortality. Although the right ventricle (RV) can adapt to an increase in afterload, progression of the pulmonary vasculopathy that characterizes PAH causes many patients to develop progressive right ventricular failure. Furthermore, acute right ventricular decompensation may develop from disorders that lead to either an acute increase in cardiac demand, such as sepsis, or to an increase in ventricular afterload, including interruptions in medical therapy, arrhythmia, or pulmonary embolism. The poor reserve of the right ventricle, RV ischemia, and adverse right ventricular influence on left ventricular filling may lead to a global reduction in oxygen delivery and multiorgan failure. There is a paucity of data to guide clinicians caring for acute right heart failure in PAH. Treatment recommendations are frequently based on animal models of acute right heart failure or case series in humans with other causes of pulmonary hypertension. Successful treatment often requires that invasive hemodynamics be used to monitor the effect of strategies that are based primarily on biological plausibility. Herein we have developed an approach based on the current understanding of RV failure in PAH and have attempted to develop a treatment paradigm based on physiological principles and available evidence.

Pulmonary hypertension in dogs: diagnosis and therapy

Pulmonary hypertension (PH) has been recognized as a clinical syndrome for many years in veterinary medicine, but routine accurate clinical diagnosis in dogs was greatly enhanced by widespread use of echocardiography and Doppler echocardiography. Most cases of PH in veterinary medicine can be categorized as precapillary or postcapillary. These subsets of patients often differ with regard to clinical presentation, response to therapy, and prognosis. Effective medical therapy is now available to treat this often-devastating clinical complication of common chronic diseases, making accurate diagnosis even more important to patient longevity and quality of life.

Weaning difficult-to-wean chronic obstructive pulmonary disease patients: a pilot study comparing initial hemodynamic effects of levosimendan and dobutamine

PURPOSE

To compare the short-term hemodynamic effects of levosimendan and dobutamine in chronic obstructive pulmonary disease (COPD) patients experiencing weaning difficulties in relation with increased left ventricular filling pressure.

MATERIALS AND METHODS

This prospective, sequential, pilot study included 10 COPD patients experiencing weaning difficulties in relation with increased left ventricular filling pressure ascertained by an increase >10 mm Hg of pulmonary artery occlusion pressure (PAOP) at the shift from mechanical to spontaneous breathing (SB). Patients received 1 h infusion of 7 μg/kg per minute of dobutamine, followed by 24-hour infusion of 0.2 μg/kg per minute levosimendan. Hemodynamic variables were measured under MV and 15 to 30 minutes after SB at baseline, at the end of dobutamine infusion, at a washout period, and after levosimendan infusion.

RESULTS

At baseline, the shift from mechanical ventilation to spontaneous ventilation was associated with a significant increase in PAOP from a median of 15 (interquartile range [IQR], 6) to 29 (9) mm Hg. Both drugs reduced significantly the level of PAOP increase at SB, but levosimendan had a greater effect than dobutamine [median PAOP increase (IQR): 5 (2) vs 9 (4) mm Hg, respectively; P < .01].

CONCLUSIONS

Both drugs reduced the magnitude of PAOP increase at SB in difficult-to-wean COPD patients. PAOP increase was reduced to a greater extent by levosimendan.

Right ventricular function in myocardial infarction complicated by cardiogenic shock: Improvement with levosimendan

OBJECTIVES

Levosimendan improves left ventricular hemodynamic function in patients with cardiogenic shock. However, its impact on right ventricular performance has not been determined. We compared the hemodynamic effects of levosimendan on left and right ventricular function in patients with intractable cardiogenic shock following myocardial infarction.

DESIGN

Observational hemodynamic study.

SETTING

Tertiary care center university hospital.

PATIENTS

Fifty-six patients with cardiogenic shock secondary to myocardial infarction were treated with percutaneous revascularization (including intra-aortic balloon pump when appropriate) and commenced on conventional inotropic therapy.

INTERVENTION

Twenty-five consecutive patients with cardiogenic shock due to myocardial infarction who had not improved sufficiently with conventional therapy (including dobutamine and norepinephrine) received levosimendan (as a bolus of 12 microg/kg per minute for 10 mins then 0.1 microg/kg per minute--0.2 mug/kg per minute) as "bail-out" therapy for 24 hrs while invasive hemodynamic parameters were recorded.

MEASUREMENTS AND MAIN RESULTS

Levosimendan therapy was associated with a significant increase in cardiac index from 2.1 +/- 0.1 to 3.0 +/- 0.2 L x min x m (p < .01). In addition, levosimendan enhanced right ventricular cardiac power index (0.14 +/- 0.19 to 0.18W +/- 0.12, p < .001), while pulmonary vascular resistance fell from 227.7 +/- 94.5 to 178.1 +/- 62.3 dyne x s x cm (p = .002). No significant change in central venous pressure or mean pulmonary artery pressure was observed. The observed hemodynamic improvement was sustained after the levosimendan infusion was stopped.

CONCLUSIONS

Levosimendan infusion for cardiogenic shock following acute myocardial infarction improved hemodynamic parameters of right ventricular performance. Furthermore, we describe the use of right ventricular cardiac power index as a hemodynamic parameter of right ventricular performance.

Levosimendan is not effective in reducing pulmonary pressures in patients with idiopathic pulmonary arterial hypertension: report of two cases

Currently, prostacyclin, endothelin receptor antagonists and phosphodiesterase inhibitors are recommended therapy in idiopathic pulmonary arterial hypertension. However, each of these drugs has limited efficacy in the improvement of clinical symptoms, pulmonary hemodynamics and long-term survival. Levosimendan, a novel calcium-sensitizing inodilator agent, has been shown to have pulmonary vasodilatory action. However, the potential pulmonary vasodilating effect of levosimendan in patients with idiopathic pulmonary arterial hypertension remains unclear. Levosimendan administered in two patients with nonvasoreactive idiopathic pulmonary arterial hypertension exhibited deterioration in clinical status, and, contrary to what was expected, levosimendan was found to increase pulmonary pressures and did not lead to a substantial improvement of the patient's condition.