Acute right ventricular failure--from pathophysiology to new treatments

Demystifying Volume Status: An Ultrasound-Guided Physiologic Framework

TOPIC IMPORTANCE

Accurate assessment of a patient's volume status is crucial in many conditions, informing decisions on fluid prescribing, vasoactive agents, and decongestive therapies. Determining a patient's volume status is challenging because of limitations in examination and investigations and the complexities of fluid homeostasis in disease states. Point-of-care ultrasound (POCUS) is useful in assessing hemodynamic parameters related to volume status, fluid responsiveness, and fluid tolerance. It requires understanding several physiologic concepts to interpret and integrate POCUS findings accurately into volume-related clinical decision-making.

REVIEW FINDINGS

The following concepts serve as a scaffold for a comprehensive volume status assessment: central venous pressure, right-sided heart function, left-sided heart assessment, extravascular volume, and venous congestion. POCUS allows us access to these hemodynamic and structural data points as an extension and refinement of the physical examination. Often, multiple POCUS applications are used, and findings must be integrated with the rest of the clinical evaluation. We illustrate this using 3 common scenarios: hypotension, hypoxia, and acute kidney injury. Clinicians must be aware of the strengths and weaknesses of findings in different physiologic states and the potential pitfalls of image acquisition and interpretation. Further studies are necessary to determine the benefits and clinical outcomes of a POCUS-directed volume status assessment.

SUMMARY

Volume status assessment is ubiquitous, yet is challenging to perform. This review summarizes foundational physiologic concepts relevant to volume status evaluation and highlights how multiorgan POCUS elucidates hemodynamic parameters that can be combined with the conventional clinical assessment to make fluid-related decisions.

A battery-less wireless implant for the continuous monitoring of vascular pressure, flow rate and temperature

Devices for monitoring blood haemodynamics can guide the perioperative management of patients with cardiovascular disease. Current technologies for this purpose are constrained by wired connections to external electronics, and wireless alternatives are restricted to monitoring of either blood pressure or blood flow. Here we report the design aspects and performance parameters of an integrated wireless sensor capable of implantation in the heart or in a blood vessel for simultaneous measurements of pressure, flow rate and temperature in real time. The sensor is controlled via long-range communication through a subcutaneously implanted and wirelessly powered Bluetooth Low Energy system-on-a-chip. The device can be delivered via a minimally invasive transcatheter procedure or it can be mounted on a passive medical device such as a stent, as we show for the case of the pulmonary artery in a pig model and the aorta and left ventricle in a sheep model, where the device performs comparably to clinical tools for monitoring of blood flow and pressure. Battery-less and wireless devices such as these that integrate capabilities for flow, pressure and temperature sensing offer the potential for continuous monitoring of blood haemodynamics in patients.

Cardiac dysfunction in severe pediatric acute respiratory distress syndrome: the right ventricle in search of the right therapy

Severe acute respiratory distress syndrome in children, or PARDS, carries a high risk of morbidity and mortality that is not fully explained by PARDS severity alone. Right ventricular (RV) dysfunction can be an insidious and often under-recognized complication of severe PARDS that may contribute to its untoward outcomes. Indeed, recent evidence suggest significantly worse outcomes in children who develop RV failure in their course of PARDS. However, in this narrative review, we highlight the dearth of evidence regarding the incidence of and risk factors for PARDS-associated RV dysfunction. While we wish to draw attention to the absence of available evidence that would inform recommendations around surveillance and treatment of RV dysfunction during severe PARDS, we leverage available evidence to glean insights into potentially helpful surveillance strategies and therapeutic approaches.

Cardiovascular Subphenotypes in Acute Respiratory Distress Syndrome

OBJECTIVES

To use clustering methods on transthoracic echocardiography (TTE) findings and hemodynamic parameters to characterize circulatory failure subphenotypes and potentially elucidate underlying mechanisms in patients with acute respiratory distress syndrome (ARDS) and to describe their association with mortality compared with current definitions of right ventricular dysfunction (RVD).

DESIGN

Retrospective, single-center cohort study.

SETTING

University Hospital ICU, Birmingham, United Kingdom.

PATIENTS

ICU patients that received TTE within 7 days of ARDS onset between April 2016 and December 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Latent class analysis (LCA) of TTE/hemodynamic parameters was performed in 801 patients, 62 years old (interquartile range, 50-72 yr old), 63% male, and 40% 90-day mortality rate. Four cardiovascular subphenotypes were identified: class 1 (43%; mostly normal left and right ventricular [LV/RV] function), class 2 (24%; mostly dilated RV with preserved systolic function), class 3 (13%, mostly dilated RV with impaired systolic function), and class 4 (21%; mostly high cardiac output, with hyperdynamic LV function). The four subphenotypes differed in their characteristics and outcomes, with 90-day mortality rates of 19%, 40%, 78%, and 59% in classes 1-4, respectively ( p < 0.0001). Following multivariable logistic regression analysis, class 3 had the highest odds ratio (OR) for mortality (OR, 6.9; 95% CI, 4.0-11.8) compared with other RVD definitions. Different three-variable models had high diagnostic accuracy in identifying each of these latent subphenotypes.

CONCLUSIONS

LCA of TTE parameters identified four cardiovascular subphenotypes in ARDS that more closely aligned with circulatory failure mechanisms and mortality than current RVD definitions.

A new machine learning model for predicting severity prognosis in patients with pulmonary embolism: Study protocol from Wenzhou, China

INTRODUCTION

Pulmonary embolism (PE) is a common thrombotic disease and potentially deadly cardiovascular disorder. The ratio of clinical misdiagnosis and missed diagnosis of PE is very large because patients with PE are asymptomatic or non-specific.

METHODS

Using the clinical data from the First Affiliated Hospital of Wenzhou Medical University (Wenzhou, China), we proposed a swarm intelligence algorithm-based kernel extreme learning machine model (SSACS-KELM) to recognize and discriminate the severity of the PE by patient's basic information and serum biomarkers. First, an enhanced method (SSACS) is presented by combining the salp swarm algorithm (SSA) with the cuckoo search (CS). Then, the SSACS algorithm is introduced into the KELM classifier to propose the SSACS-KELM model to improve the accuracy and stability of the traditional classifier.

RESULTS

In the experiments, the benchmark optimization performance of SSACS is confirmed by comparing SSACS with five original classical methods and five high-performance improved algorithms through benchmark function experiments. Then, the overall adaptability and accuracy of the SSACS-KELM model are tested using eight public data sets. Further, to highlight the superiority of SSACS-KELM on PE datasets, this paper conducts comparison experiments with other classical classifiers, swarm intelligence algorithms, and feature selection approaches.

DISCUSSION

The experimental results show that high D-dimer concentration, hypoalbuminemia, and other indicators are important for the diagnosis of PE. The classification results showed that the accuracy of the prediction model was 99.33%. It is expected to be a new and accurate method to distinguish the severity of PE.

Modeling renal autoregulation in a hemodynamic, first-trimester gestational model

The maternal cardiovascular system, led by renal volume regulatory responses, changes during pregnancy to ensure an adequate circulation for fetal development and growth. Circulatory maladjustment predisposes to hypertensive complications during pregnancy. Mathematical models can be used to gain insight in the gestational cardiovascular physiology. In this study, we developed an accurate, robust, and transparent model for renal autoregulation implemented in an existing circulatory gestational model. This renal autoregulation model aims to maintain steady glomerular pressure by the myogenic response, and glomerular filtration rate by tubuloglomerular feedback, both by inducing a change in the radius, and thus resistance, of the afferent arteriole. The modeled response of renal blood flow and the afferent arteriole following blood pressure increase were compared to published observations in rats. With solely the myogenic response, our model had a maximum deviation of 7% in change in renal blood flow and 7% in renal vascular resistance. When both the myogenic response and tubuloglomerular feedback were concurrently activated, the maximum deviation was 7% in change in renal blood flow and 5% in renal vascular resistance. These results show that our model is able to represent renal autoregulatory behavior comparable to empirical data. Further studies should focus on extending the model with other regulatory mechanisms to understand the hemodynamic changes in healthy and complicated pregnancy.

Cardiovascular subphenotypes in patients with COVID-19 pneumonitis whose lungs are mechanically ventilated: a single-centre retrospective observational study

Unsupervised clustering methods of transthoracic echocardiography variables have not been used to characterise circulatory failure mechanisms in patients with COVID‐19 pneumonitis. We conducted a retrospective, single‐centre cohort study in ICU patients with COVID‐19 pneumonitis whose lungs were mechanically ventilated and who underwent transthoracic echocardiography between March 2020 and May 2021. We performed latent class analysis of echocardiographic and haemodynamic variables. We characterised the identified subphenotypes by comparing their clinical parameters, treatment responses and 90‐day mortality rates. We included 305 patients with a median (IQR [range]) age 59 (49–66 [16–83]) y. Of these, 219 (72%) were male, 199 (65%) had moderate acute respiratory distress syndrome and 113 (37%) did not survive more than 90 days. Latent class analysis identified three cardiovascular subphenotypes: class 1 (52%; normal right ventricular function); class 2 (31%; right ventricular dilation with mostly preserved systolic function); and class 3 (17%; right ventricular dilation with systolic impairment). The three subphenotypes differed in their clinical characteristics and response to prone ventilation and outcomes, with 90‐day mortality rates of 22%, 42% and 73%, respectively (p < 0.001). We conclude that the identified subphenotypes aligned with right ventricular pathophysiology rather than the accepted definitions of right ventricular dysfunction, and these identified classifications were associated with clinical outcomes.

Care of the critically ill neonate with hypoxemic respiratory failure and acute pulmonary hypertension: framework for practice based on consensus opinion of neonatal hemodynamics working group

Circulatory transition after birth presents a critical period whereby the pulmonary vascular bed and right ventricle must adapt to rapidly changing loading conditions. Failure of postnatal transition may present as hypoxemic respiratory failure, with disordered pulmonary and systemic blood flow. In this review, we present the biological and clinical contributors to pathophysiology and present a management framework.

Acute Right Ventricular Dysfunction Secondary to Hereditary Angioedema Exacerbation

This is a case report of a 31-year-old woman with past medical history of hereditary angioedema (HAE) who developed acute right ventricular dysfunction. The patient presented to the emergency department with complaints of acute abdominal pain and swelling. Her electrocardiogram demonstrated sinus tachycardia and T wave inversion in leads V1-V3, otherwise without findings suggestive of ischemia. Troponin was elevated at 1.83 ng/mL. A transthoracic echocardiogram showed normal left ventricular function with ejection fraction of 65-70%, but the right ventricle (RV) was dilated and severely hypokinetic and there was moderate tricuspid regurgitation. Patient was managed symptomatically for her HAE exacerbation. Her abdominal swelling resolved, troponins continued to trend down, and she was discharged home after three days. A follow up echocardiogram done six months later demonstrated normal RV function. 

Effects of Pulsatile Frequency of Left Ventricular Assist Device (LVAD) on Coronary Perfusion: A Numerical Simulation Study

Background

Left ventricular assist devices (LVADs) with counter-pulsation mode have been widely used to support left ventricular function and improve coronary circulation. However, the frequency characteristics of the coronary system have not been considered. The aim of this study was to investigate the effects of pulsatile frequency of LVADs on coronary perfusion.

Material/Methods

First, a lumped parameter (LP) model incorporating coronary circulation, systemic circulation, left heart, and LVAD was established to simulate the cardiovascular system. Then, the frequency characteristics of the coronary system were analyzed and the calculation results showed that the pulsatile frequency of the LVAD has a substantial effect on coronary blood flow. To verify the accuracy of the theoretical analysis, the hemodynamic effects of the LVAD on the coronary artery were compared under 4 support modes: co-pulsation mode, and counter-pulsation modes in synchronization ratios of 1: 1, 2: 1, and 3: 1.

Results

We found that the coronary flow increased by 5% when the working mode changed from co-pulsation to counter-pulsation in a synchronization ratio of 1: 1, and by an additional 6% when the working mode changed from counter-pulsation in a synchronization ratio of 1: 1 to counter-pulsation in a synchronization ratio of 3: 1.

Conclusions

This work provides a useful method to increase coronary perfusion and may be beneficial for improving myocardial function in patients with end-stage heart failure, especially those with ischemic cardiomyopathy (ICM).

Pathological Findings of Postmortem Biopsies From Lung, Heart, and Liver of 7 Deceased COVID-19 Patients

Background. A novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been affecting almost all nations around the world. Most infected patients who have been admitted to intensive care units show SARS signs. In this study, we aimed to achieve a better understanding of pathological alterations that take place during the novel coronavirus infection in most presumed affected organs. Methods. We performed postmortem core needle biopsies from lung, heart, and liver on 7 deceased patients who had died of coronavirus disease 2019. Prepared tissue sections were observed by 2 expert pathologists. Results. Diffuse alveolar damage was the main pathologic finding in the lung tissue samples. Patients with hospitalization durations of more than 10 days showed evidence of organization. Multinucleated cells in alveolar spaces and alveolar walls, atypical enlarged cells, accumulation of macrophages in alveolar spaces, and congestion of vascular channels were the other histopathologic alteration of the lung. None of our heart biopsy samples met the criteria for myocarditis. Liver biopsies showed congestion, micro- and macro-vesicular changes, and minimal to mild portal inflammation, in the majority of cases. Conclusions. Similar to the previous coronavirus infection in 2003, the main pathologic finding in the lung was diffuse alveolar damage with a pattern of organization in prolonged cases. The SARS-CoV-2 infection does not cause myocarditis, and the ischemia of myocardium is the most probable justification of the observed pathologic changes in the heart. Liver tissue sections mostly showed nonspecific findings; however, ischemia of the liver can be identified in some cases.

Acute Respiratory Failure in Interstitial Lung Disease Complicated by Pulmonary Hypertension

Interstitial lung disease represents a group of diffuse parenchymal lung diseases with overwhelming morbidity and mortality when complicated by acute respiratory failure. Recently, trials investigating outcomes and their determinants have provided insight into these high mortality rates. Pulmonary hypertension is a known complication of interstitial lung disease and there is high prevalence in idiopathic pulmonary fibrosis, connective tissue disease, and sarcoidosis subtypes. Interstitial lung disease associated pulmonary hypertension has further increased mortality with acute respiratory failure, and there is limited evidence to guide management. This review describes investigations and management of interstitial lung disease associated acute respiratory failure complicated by pulmonary hypertension. Despite the emerging attention on interstitial lung disease associated acute respiratory failure and the influence of pulmonary hypertension, critical care management remains a clinical and ethical challenge.

Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine: A Prospective Clinical Study

PURPOSE

The aim of the study was to simultaneously optimize contrast media (CM) injection and scan parameters for the individual patient during computed tomography pulmonary angiography (CTPA).

METHODS

In this study (NCT02611115), 235 consecutive patients suspected of having pulmonary embolism were prospectively enrolled. Automated kV selection software on a third-generation multidetector computed tomography adapted tube voltage to the individual patient, based on scout scans. The contrast injection protocol was adapted to both patient body weight and kV-setting selection via a predefined formula, based on previous research. Injection data were collected from a contrast media and radiation dose monitoring software. Attenuation was measured in Hounsfield units (HU) in the pulmonary trunk (PT); attenuation values 200 HU or greater were considered diagnostic. Subjective image quality was assessed by using a 4-point Likert scale at the level of the PT, lobar, segmental, and subsegmental arteries. Results between groups were reported as mean ± SD.

RESULTS

Two hundred twenty-two patients (94%) were scanned at a kV setting below 100 kV: n = 108 for 70 kV, n = 82 for 80 kV, and n = 32 for 90 kV. Mean CM bolus volume (in milliliters) and total iodine load (in grams of iodine) for 70 to 90 kV were as follows: 24 ± 3 mL and 7 ± 1 g I, 29 ± 4 mL and 9 ± 2 g I, and 38 ± 4 mL and 11 ± 1 g I, respectively. Mean flow rates (in milliliters per second) and iodine delivery rates (in grams of iodine per second) were 3.0 ± 0.4 mL/s and 0.9 ± 0.1 g I/s (70 kV), 3.6 ± 0.4 mL/s and 1.0 ± 0.1 g I/s (80 kV), and 4.7 ± 0.5 mL/s and 1.3 ± 0.1 g I/s (90 kV). Mean radiation doses were 1.3 ± 0.3 mSv at 70 kV, 1.7 ± 0.4 mSv at 80 kV, and 2.2 ± 0.6 mSv at 90 kV. Mean vascular attenuation in the PT for each kV group was as follows: 397 ± 101 HU for 70 kV, 398 ± 96 HU for 80 kV, and 378 ± 100 HU for 90 kV, P = 0.59. Forty-six patients (21%) showed pulmonary embolism on the CTPA. One scan (90 kV) showed nondiagnostic segmental pulmonary arteries, and 5% of subsegmental arteries were of nondiagnostic image quality. All other segments were considered diagnostic-excellent subjective image quality.

CONCLUSIONS

Simultaneously optimizing both CM injections and kV settings to the individual patient in CTPA results in diagnostic attenuation with on average 24 to 38 mL of CM volume and a low radiation dose for most patients. This individualized protocol may help overcome attenuation-variation problems between patients and kV settings in CTPA.

Adaptation to acute pulmonary hypertension in pigs

The extent of right ventricular compensation compared to the left ventricle is restricted and varies among individuals, which makes it difficult to define. While establishing a model of acute pulmonary hypertension in pigs we observed two different kinds of compensation in our animals. Looking deeper into the hemodynamic data we tried to delineate why some animals could compensate and others could not. Pulmonary hypertension (mean pressure 45 mmHg) was induced gradually by infusion of a stable thromboxane A₂ analogue U46619 in a porcine model (n = 22). Hemodynamic data (pressure‐volume loops, strain‐analysis of echocardiographic data and coronary flow measurements) were evaluated retrospectively for the short‐term right ventricular compensatory mechanisms and limits (Roehl et al. [2012] Acta Anaesthesiol. Scand., 56:449–58) 10 animals showed stable arterial blood pressures, whereas 12 pigs exhibited a significant drop of 16.4 ± 9.9 mmHg. Cardiac output and heart rate were comparable in both groups. In contrast, right ventricular contractility and coronary flow only rose in the stable group. The unchanging values in the decrease group correlated with an increasing ST‐segment depression and a loss of ventricular synchronism and resulted in a larger septum bulging to the right ventricle. Simultaneously, a reduced left‐ventricular end‐diastolic volume and a missing improvement in contractility in the posterior septal and inferior free wall of the left ventricle have been observed. Our findings suggest that right ventricular compensation during acute pulmonary hypertension is strongly dependent on the individual capability to increase coronary flow. The cause for inter‐individual variability could be the dimension and reactivity of the coronary system.

Vardenafil and Weaning from Inhaled Nitric Oxide: Effect on Pulmonary Hypertension in ARDS

We report a 66-year-old patient with refractory pulmonary hypertension secondary to ARDS who was being treated with inhaled nitric oxide. Enteral vardenafil (phosphodiesterase-5 inhibitor) was tried at two different doses (10 mg and 5 mg), in order to wean the patient from nitric oxide. The higher dose decreased pulmonary pressure but caused systemic hypotension and the drug was discontinued. Subsequently, a 5 mg dose of vardenafil decreased pulmonary pressure without hypotension. Pulmonary hypertension was controlled using vardenafil 10-15 mg divided in 2-3 daily doses. This therapy allowed nitric oxide withdrawal, weaning from mechanical ventilation and discharge from ICU.

Vardenafil acted in synergy with inhaled nitric oxide, permitted nitric oxide reduction and discontinuation and proved to be effective as a single, long-term treatment for pulmonary hypertension.

The PIEPEAR Workflow: A Critical Care Ultrasound Based 7-Step Approach as a Standard Procedure to Manage Patients with Acute Cardiorespiratory Compromise, with Two Example Cases Presented

Critical care ultrasound (CCUS) has been widely used as a useful tool to assist clinical judgement. The utilization should be integrated into clinical scenario and interact with other tests. No publication has reported this. We present a CCUS based "7-step approach" workflow-the PIEPEAR Workflow-which we had summarized and integrated our experience in CCUS and clinical practice into, and then we present two cases which we have applied the workflow into as examples. Step one is "problems emerged?" classifying the signs of the deterioration into two aspects: acute circulatory compromise and acute respiratory compromise. Step two is "information clear?" quickly summarizing the patient's medical history by three aspects. Step three is "focused exam launched": (1) focused exam of the heart by five views: the assessment includes (1) fast and global assessment of the heart (heart glance) to identify cases that need immediate life-saving intervention and (2) assessing the inferior vena cava, right heart, diastolic and systolic function of left heart, and systematic vascular resistance to clarify the hemodynamics. (2) Lung ultrasound exam is performed to clarify the predominant pattern of the lung. Step four is "pathophysiologic changes reported." The results of the focused ultrasound exam were integrated to conclude the pathophysiologic changes. Step five is "etiology explored" diagnosing the etiology by integrating Step two and Step four and searching for the source of infection, according to the clues extracted from the focused ultrasound exam; additional ultrasound exams or other tests should be applied if needed. Step six is "action" supporting the circulation and respiration sticking to Step four. Treat the etiologies according step five. Step seven is "recheck to adjust." Repeat focused ultrasound and other tests to assess the response to treatment, adjust the treatment if needed, and confirm or correct the final diagnosis. With two cases as examples presented, we insist that applying CCUS with 7-step approach workflow is easy to follow and has theoretical advantages. The coming research on its value is expected.

Acute Right Ventricular Failure Postintubation in a Mitral Stenosis Patient

Mitral stenosis (MS) is prevalent in 0.02-0.2% of the population in developed countries. The pathophysiology of MS results in elevated left atrial pressures and over-time results in pulmonary hypertension (HTN) which ultimately affects the right ventricle. In addition, MS restricts the diastolic filling of the left ventricle. Therefore, during induction patients with MS are limited by their ability to increase cardiac output by increasing stroke volume. Anesthesia goals in severe MS are to avoid sudden changes in heart rate, as well as systemic and pulmonary artery pressures. We report a patient who sustained severe hypotension upon induction and intubation which was resistant to conventional medications. Intraoperative transesophageal echocardiography displayed unique right atrial and right ventricular dilatation. In addition, the leftward inter-ventricular, inter-atrial septal shift and septal bounce were noted as the characteristic findings. Intravenous epinephrine bolus was administered to achieve normo-tension and normal chamber dimensions and interventricular septal position.

Right Ventricular Perfusion

Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure–flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins. These differences promote the maintenance of right ventricular oxygen supply–demand balance and provide relative resistance to ischemia-induced contractile dysfunction and infarction, but they may be compromised during acute or chronic increases in right ventricle afterload resulting from pulmonary arterial hypertension. Contractile function of the thin-walled right ventricle is exquisitely sensitive to afterload. Acute increases in pulmonary arterial pressure reduce right ventricular stroke volume and, if sufficiently large and prolonged, result in right ventricular failure. Right ventricular ischemia plays a prominent role in these effects. The risk of right ventricular ischemia is also heightened during chronic elevations in right ventricular afterload because microvascular growth fails to match myocyte hypertrophy and because microvascular dysfunction is present. The right coronary circulation is more sensitive than the left to α-adrenergic–mediated constriction, which may contribute to its greater propensity for coronary vasospasm. This characteristic of the right coronary circulation may increase its vulnerability to coronary vasoconstriction and impaired right ventricular perfusion during administration of α-adrenergic receptor agonists.

The Dark Side of the Moon: The Right Ventricle

The aim of this review article is to summarize current knowledge of the pathophysiology underlying right ventricular failure (RVF), focusing, in particular, on right ventricular assessment and prognosis. The right ventricle (RV) can tolerate volume overload well, but is not able to sustain pressure overload. Right ventricular hypertrophy (RVH), as a response to increased afterload, can be adaptive or maladaptive. The easiest and most common way to assess the RV is by two-dimensional (2D) trans-thoracic echocardiography measuring surrogate indexes, such as tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and tissue Doppler velocity of the lateral aspect of the tricuspid valvular plane. However, both volumes and function are better estimated by 3D echocardiography and cardiac magnetic resonance (CMR). The prognostic role of the RV in heart failure (HF), pulmonary hypertension (PH), acute myocardial infarction (AMI), and cardiac surgery has been overlooked for many years. However, several recent studies have placed much greater importance on the RV in prognostic assessments. In conclusion, RV dimensions and function should be routinely assessed in cardiovascular disease, as RVF has a significant impact on disease prognosis. In the presence of RVF, different therapeutic approaches, either pharmacological or surgical, may be beneficial.

The utilization of critical care ultrasound to assess hemodynamics and lung pathology on ICU admission and the potential for predicting outcome

Aim

Critical care ultrasound (CCUS) has been used by many Intensive Care Units(ICUs) worldwide, so as to guiding the diagnosis and the treatment. However, none of the publications currently systematically describe the utilization of CCUS to analyze the characteristics of hemodynamics and lung pathology upon the new admission to ICU and its potential role in patients’ prognosis prediction. In this retrospective clinical study, we have demonstrated and analyzed the characteristics of hemodynamics and lung pathology assessed by CCUS and investigated its potential to predict patient outcome.

Methods

We have described and analyzed the epidemic characteristics of hemodynamics and lung pathology assessed by CCUS on ICU admission, which based on our database of 451 cases from the biggest medical center in Western China, between November 2014 and October 2015. The patients’ demographics, clinical characteristics, prognosis and ultrasonic pattern of hemodynamics and lung pathology had been analyzed. A bivariate logistic regression model was established to identify the correlation between the ultrasonic variables on admission and the ICU mortality.

Results

The mean age of the 451 patients was 56.7±18.7 years; the mean APACHE II score was 19.0±7.9, the ICU mortality was 30.6%. Patients received CCUS examination of pericardial, right ventricle (RV) wall motion, left ventricle (LV) wall motion, LV systolic function, LV diastolic function, lung and volume of inferior vena cava (IVC) were 423(93.8%), 418(92.7%), 392(86.9%), 389(86.3%), 383(84.9%), 440(97.6%), 336(74.5%), respectively; The univariate analysis revealed that length of mechanical ventilation was significantly correlated with the diameter of IVC, tricuspid annular plane systolic excursion(TAPSE), mitral annular plane systolic excursion(MAPSE), early diastolic transmitral velocity to early mitral annulus diastolic velocity(E/e’) (p = 0.016, 0.011, 0.000, 0.049, respectively); The TAPSE, ejection fraction(EF), MAPSE, lung ultrasound score (LUS score) (p = 0.000, 0.028, 0.000, 0.011, respectively) were significantly related to ICU mortality. The multivariate analysis demonstrated that APACHE II, age, TAPSE, E/e’ are the independent risk factors for ICU mortality in our study.

Conclusion

CCUS examination on ICU admission which performed by the experienced physician provide valuable information to assist the caregivers in understanding the comprehensive outlook of the characteristics of hemodynamics and lung pathology. Those key variables obtained by CCUS predict the possible prognosis of patients, hence deserve more attention in clinical decision making.

Expert consensus document: Echocardiography and lung ultrasonography for the assessment and management of acute heart failure

Echocardiography is increasingly recommended for the diagnosis and assessment of patients with severe cardiac disease, including acute heart failure. Although previously considered to be within the realm of cardiologists, the development of ultrasonography technology has led to the adoption of echocardiography by acute care clinicians across a range of specialties. Data from echocardiography and lung ultrasonography can be used to improve diagnostic accuracy, guide and monitor the response to interventions, and communicate important prognostic information in patients with acute heart failure. However, without the appropriate skills and a good understanding of ultrasonography, its wider application to the most acutely unwell patients can have substantial pitfalls. This Consensus Statement, prepared by the Acute Heart Failure Study Group of the ESC Acute Cardiovascular Care Association, reviews the existing and potential roles of echocardiography and lung ultrasonography in the assessment and management of patients with acute heart failure, highlighting the differences from established practice where relevant.

A novel clinical index for the assessment of RVD in acute pulmonary embolism: Blood pressure index

BACKGROUND

This study aims to investigate the role of the blood pressure index (BPI), which is a new index that we developed, in detection of right ventricular dysfunction (RVD) in acute pulmonary embolism (APE).

METHODS

A total of 539 patients, (253 males and 286 females), diagnosed with APE using computer tomography pulmonary angiography were included in the study. The BPI was obtained by dividing systolic blood pressure (SBP) by diastolic blood pressure (DBP).

RESULTS

Mean DBP (75±11mmHg vs 63±15mmHg; p<0.001, respectively) was found to be higher in RVD patients compared to those without RVD, whereas BPI (1.5±0.1 vs 1.9±0.2; p<0.001, respectively) was lower. Examining the performance of BPI in prediction of RVD using receiver operating characteristic curve analysis (area under curve±SE=0.975±0.006; p<0.001), it was found that BPI could predict RVD with very high sensitivity (92.8%) and specificity (100%) and had a positive predictive value of 100% and a negative predictive value of 42.1%. According to the analysis, the highest youden index for the optimal prediction value was found to be 0.478 and the BPI≤1.4 was found to predict mortality 68.6% sensitivity and 80.8% specificity (Area under curve±SE=0.777±0.051; p<0.001).

CONCLUSIONS

We found that BPI was an index with high positive predictive value and low negative predictive value in detection of RVD.

[Posttraumatic thromboembolic complications: Incidence, risk factors, pathophysiology and prevention]

Venous thromboembolism (VTE) remains a major challenge in critically ill patients. Subjects admitted in intensive care unit (ICU), in particular trauma patients, are at high-risk for both deep vein thrombosis (DVT) and pulmonary embolism (PE). The rate of symptomatic PE in injured patients has been reported previously ranging from 1 to 6%. The high incidence of posttraumatic venous thromboembolic events is well known. In fact, major trauma is a hypercoagulable state. Several factors placing the individual patient at a higher risk for the development of DVT and PE have been suggested: high ISS score, meningeal hemorrhage and spinal cord injuries have frequently been reported as a significant risk factor for VTEs after trauma. Posttraumatic pulmonary embolism traditionally occurs after a period of at least 5 days from trauma. The prevention can reduce the incidence and mortality associated with the pulmonary embolism if it is effective. There is no consensus is now available about the prevention of venous thromboembolism in trauma patients.

A pig model of acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction

Background

The aim of this study was to construct a non-invasive model for acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction. Intact animal models are vital to improving our understanding of the pathophysiology of acute right ventricular failure. Acute right ventricular failure is caused by increased afterload of the right ventricle by chronic or acute pulmonary hypertension combined with regionally or globally reduced right ventricular contractile capacity. Previous models are hampered by their invasiveness; this is unfortunate as the pulmonary circulation is a low-pressure system that needs to be studied in closed chest animals. Hypoxic pulmonary vasoconstriction is a mechanism that causes vasoconstriction in alveolar vessels in response to alveolar hypoxia. In this study we explored the use of hypoxic pulmonary vasoconstriction as a means to increase the pressure load on the right ventricle.

Results

Pulmonary hypertension was induced by lowering the FiO₂ to levels below the physiological range in eight anesthetized and mechanically ventilated pigs. The pigs were monitored with blood pressure measurements and blood gases. The mean pulmonary artery pressures (mPAP) of the animals increased from 18.3 (4.2) to 28.4 (4.6) mmHg and the pulmonary vascular resistance (PVR) from 254 (76) dyns/cm⁵ to 504 (191) dyns/cm⁵, with a lowering of FiO₂ from 0.30 to 0.15 (0.024). The animals’ individual baseline mPAPs varied substantially as did their response to hypoxia. The reduced FiO₂ level yielded an overall lowering in oxygen offer, but the global oxygen consumption was unaltered.

Conclusions

We showed in this study that the mPAP and the PVR could be raised by approximately 100% in the study animals by lowering the FiO₂ from 0.30 to 0.15 (0.024). We therefore present a novel method for minimally invasive (closed chest) right ventricular afterload manipulations intended for future studies of acute right ventricular failure. The method should in theory be reversible, although this was not studied in this work.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2333-7) contains supplementary material, which is available to authorized users.

Indications for manual lung hyperinflation (MHI) in the mechanically ventilated patient with chronic obstructivepulmonary disease

Manual lung hyperinflation (MHI) can enhance secretion clearance, improve total lung/thorax compliance and assistin the resolution of acute atelectasis. To enhance secretion clearance in the intubated patient, the evidence highlights the need to maximize expiratory flow. Chronic pulmonary diseases such as chronic obstructive pulmonary disease(COPD) have often been cited as potential precautions and/or contra-indications to the use of manual lung hyperinflation (MHI). There is an absence of evidence on the effects of MHI in the patient with COPD. Research on the effects of mechanical ventilation in the patient with COPD providesa useful clinical examination of the effect of positive pressure on cardiac and pulmonary function. The potential effects of MHI in the COPD patient group were extrapolated on the basis of the MHI and mechanical ventilation literature. There is the potential for MHI to have both detrimental and beneficial effects on cardiac and pulmonary functionin patients with COPD. The potential detrimental effects of MHI may include either, increased intrinsic peep throughinadequate time for expiration by the breath delivery rate, tidal volume delivered or through the removal of appliedextemal PEEP thereby causing more dynamic airway compression compromising downward expiratory flow, which may also retard bronchial mucus transport. MHI may also increase right ventricular after load through raised intrathoracic pressures with lung hyperinflation, and may therefore impair right ventricular function in patients with evidence of cor pulmonale. There is the potential for beneficial effectsfrom MHI in the intubated COPD patient group (i.e., secretion clearance), but further research is required, especially on the effect of MHI on inspiratory and expiratory flowrate profiles in this patient group. The more controlled delivery of lung hyperinflation through the use of the mechanical ventilator may be a more optimal means of providinglunghyperinflation and shouldbe furtherinvestigated.

The Failing Heart Under Stress: Echocardiography is an Essential Monitoring Tool in the Intensive Care Unit

Echocardiography has been evolving to play a pivotal role in hemodynamic management, both intraoperatively and at the bedside. A full assessment of hemodynamics necessitates the use of all of the options available on modern echocardiographs. This introductory review provides insight into three important issues of hemodynamic monitoring by echocardiography: evaluation of preloading conditions, assessment of systolic function, and contractility and estimation of afterload. Mastering these three features will help in a minimally invasive approach of hemodynamic instability.

Similar hemodynamic decongestion with vasodilators and inotropes: systematic review, meta-analysis, and meta-regression of 35 studies on acute heart failure

BACKGROUND

Acute heart failure (AHF) with reduced left-ventricular ejection fraction (LVEF) is often a biventricular congested state. The comparative effect of vasodilators and inotropes on the right- and/or left-sided congestion is unknown.

METHODS AND RESULTS

A systematic review, meta-analysis, and meta-regression of AHF studies using pulmonary artery catheter were performed using PubMed, Embase, and Cochrane library. Data from 35 studies, including 3016 patients, were studied. Included patients had a weighted mean age of 60 years, left-ventricular ejection fraction (LVEF) of 24 %, and plasma B-type natriuretic peptide (BNP) of 892 pg/ml. Both the left- and right-ventricular filling pressures were elevated: weighted mean pulmonary artery wedge pressure (PAWP) was 25 mmHg (range 17-31 mmHg) and right atrial pressure (RAP) 12 mmHg (range 7-18 mmHg). Vasodilators and inotropes had similar beneficial effects on PAWP [-6.3 mmHg (95 % CI -7.4 to -5.2 mmHg) and -5.8 mmHg (95 % CI -7.6 to -4.0 mmHg), respectively] and RAP [-2.9 mmHg (95 % CI -3.8 to -2.1 mmHg) and -2.8 mmHg (95 % CI -3.8 to -1.7 mmHg), respectively]. Among inotropes, inodilators, such as levosimendan, have greater beneficial effect on the left-ventricular filling pressure than dobutamine. Drug-induced improvement of PAWP tightly paralleled that of RAP with all studied drugs (r ² = 0.90, p < 0.001). Vasodilators and inotropes had no short-term effect of renal function.

CONCLUSION

The left- and right-sided filling pressures are similarly improved by vasodilators or inotropes, in AHF with reduced LVEF.

Management of pulmonary hypertension and right heart failure in the intensive care unit

Management of acute right ventricular failure, both with and without coexisting pulmonary hypertension, is a common challenge encountered in the intensive care setting. Both right ventricular dysfunction and pulmonary hypertension portend a poor prognosis, regardless of the underlying cause and are associated with significant morbidity and mortality. The right ventricle is embryologically distinct from the left ventricle and has unique morphologic and functional properties. Management of right ventricular failure and pulmonary hypertension in the intensive care setting requires tailored hemodynamic management, pharmacotherapy, and often mechanical circulatory support. Unfortunately, our understanding of the management of right ventricular failure lags behind that of the left ventricle. In this review, we will explore the underlying pathophysiology of the failing right ventricle and pulmonary vasculature in patients with and without pulmonary hypertension and discuss management strategies based on evidence-based studies as well as our current understanding of the underlying physiology.

Acute heart failure and cardiogenic shock: a multidisciplinary practical guidance

PURPOSE

Acute heart failure (AHF) causes high burden of mortality, morbidity, and repeated hospitalizations worldwide. This guidance paper describes the tailored treatment approaches of different clinical scenarios of AHF and CS, focusing on the needs of professionals working in intensive care settings.

RESULTS

Tissue congestion and hypoperfusion are the two leading mechanisms of end-organ injury and dysfunction, which are associated with worse outcome in AHF. Diagnosis of AHF is based on clinical assessment, measurement of natriuretic peptides, and imaging modalities. Simultaneously, emphasis should be given in rapidly identifying the underlying trigger of AHF and assessing severity of AHF, as well as in recognizing end-organ injuries. Early initiation of effective treatment is associated with superior outcomes. Oxygen, diuretics, and vasodilators are the key therapies for the initial treatment of AHF. In case of respiratory distress, non-invasive ventilation with pressure support should be promptly started. In patients with severe forms of AHF with cardiogenic shock (CS), inotropes are recommended to achieve hemodynamic stability and restore tissue perfusion. In refractory CS, when hemodynamic stabilization is not achieved, the use of mechanical support with assist devices should be considered early, before the development of irreversible end-organ injuries.

CONCLUSION

A multidisciplinary approach along the entire patient journey from pre-hospital care to hospital discharge is needed to ensure early recognition, risk stratification, and the benefit of available therapies. Medical management should be planned according to the underlying mechanisms of various clinical scenarios of AHF.

In-Series Versus In-Parallel Mechanical Circulatory Support for the Right Heart: A Simulation Study

Right heart failure (RHF) is a serious health issue with increasing incidence and high mortality. Right ventricular assist devices (RVADs) have been used to support the end-stage failing right ventricle (RV). Current RVADs operate in parallel with native RV, which alter blood flow pattern and increase RV afterload, associated with high tension in cardiac muscles and long-term valve complications. We are developing an in-series RVAD for better RV unloading. This article presents a mathematical model to compare the effects of RV unloading and hemodynamic restoration on an overloaded or failing RV. The model was used to simulate both in-series (sRVAD) and in-parallel (pRVAD) (right atrium-pulmonary artery cannulation) support for severe RHF. The results demonstrated that sRVAD more effectively unloads the RV and restores the balance between RV oxygen supply and demand in RHF patients. In comparison to simulated pRVAD and published clinical and in silico studies, the sRVAD was able to provide comparable restoration of key hemodynamic parameters and demonstrated superior afterload and volume reduction. This study concluded that in-series support was able to produce effective afterload reduction and preserve the valve functionality and native blood flow pattern, eliminating complications associated with in-parallel support.

Starling curves and central venous pressure

Recent studies challenge the utility of central venous pressure monitoring as a surrogate for cardiac preload. Starting with Starling’s original studies on the regulation of cardiac output, this review traces the history of the experiments that elucidated the role of central venous pressure in circulatory physiology. Central venous pressure is an important physiologic parameter, but it is not an independent variable that determines cardiac output.

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.

Perioperative management of pulmonary hypertension during lung transplantation (a lesson for other anaesthesia settings)

Patients with pulmonary hypertension are some of the most challenging for an anaesthesiologist to manage. Pulmonary hypertension in patients undergoing surgical procedures is associated with high morbidity and mortality due to right ventricular failure, arrhythmias and ischaemia leading to haemodynamic instability. Lung transplantation is the only therapeutic option for end-stage lung disease. Patients undergoing lung transplantation present a variety of challenges for anaesthesia team, but pulmonary hypertension remains the most important. The purpose of this article is to review the anaesthetic management of pulmonary hypertension during lung transplantation, with particular emphasis on the choice of anaesthesia, pulmonary vasodilator therapy, inotropic and vasopressor therapy, and the most recent intraoperative monitoring recommendations to optimize patient care.

Systems approach to the study of stretch and arrhythmias in right ventricular failure induced in rats by monocrotaline

We demonstrate the synergistic benefits of using multiple technologies to investigate complex multi-scale biological responses. The combination of reductionist and integrative methodologies can reveal novel insights into mechanisms of action by tracking changes of in vivo phenomena to alterations in protein activity (or vice versa). We have applied this approach to electrical and mechanical remodelling in right ventricular failure caused by monocrotaline-induced pulmonary artery hypertension in rats. We show arrhythmogenic T-wave alternans in the ECG of conscious heart failure animals. Optical mapping of isolated hearts revealed discordant action potential duration (APD) alternans. Potential causes of the arrhythmic substrate; structural remodelling and/or steep APD restitution and dispersion were observed, with specific remodelling of the Right Ventricular Outflow Tract. At the myocyte level, [Ca(2+)]i transient alternans were observed together with decreased activity, gene and protein expression of the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA). Computer simulations of the electrical and structural remodelling suggest both contribute to a less stable substrate. Echocardiography was used to estimate increased wall stress in failure, in vivo. Stretch of intact and skinned single myocytes revealed no effect on the Frank-Starling mechanism in failing myocytes. In isolated hearts acute stretch-induced arrhythmias occurred in all preparations. Significant shortening of the early APD was seen in control but not failing hearts. These observations may be linked to changes in the gene expression of candidate mechanosensitive ion channels (MSCs) TREK-1 and TRPC1/6. Computer simulations incorporating MSCs and changes in ion channels with failure, based on altered gene expression, largely reproduced experimental observations.

Effectiveness of milrinone for cardiogenic shock due to massive pulmonary aspiration: a case report

Pulmonary aspiration of gastric contents is one of the most frightening complications during anesthesia. Although pulmonary aspiration of gastric contents in general surgical patients is not common and resulting long-term morbidity and mortality are rare, severe hypoxemia and other sequelae of pulmonary aspiration continue to be reported. We report a case of massive aspiration of gastric contents during induction of general anesthesia, resulting in cardiac arrest due to severe pulmonary hypertension and myocardial infarction. Sustained cardiac arrest and shock that did not respond the conventional resuscitation was successfully treated using milrinone. The patient was discharged without complications in 20 days.

Management of right ventricular dysfunction in the perioperative setting

PURPOSE OF REVIEW

This review summarizes the approach to and recent developments in the treatment of acute right ventricular dysfunction and failure in the perioperative setting. Right ventricular failure, defined as the inability to deliver sufficient blood flow through the pulmonary circulation at normal central venous pressure, is a common problem in the perioperative setting and is associated with an increased mortality. The failure of the right ventricle is caused by reduced right ventricular contractility or an increased right ventricular afterload or both.

RECENT FINDINGS

Management of acute right ventricular failure continues to be challenging because of the poor understanding of the pathophysiology, difficulties in diagnosing, the absence of guidelines, and limited therapeutic options. Recent research efforts have led to an improved understanding of the underlying mechanisms and have established a reasonable therapeutic framework.

SUMMARY

Right ventricular dysfunction may cause venous congestion and systemic hypoperfusion. After identifying right ventricular dysfunction, the primary goal is to correct reversible causes of excessive load or reduced right-ventricular contractility. If the underlying abnormalities cannot be reversed, diuretic, vasodilator, or inotropic therapy may be required.

Levosimendan reverses right-heart failure in a 51-year-old patient after heart transplantation

Primary graft failure in the early postoperative period after heart transplantation, remains a main cause of a poor outcome. Current treatment options include pharmacological (catecholamines and phosphodiesterase inhibitors) and mechanical assist device support. Pharmacological support with catecholamines is related to elevated myocardial oxygen consumption and regional hypoperfusion leading to organ damage. On the other hand, levosimendan, as a calcium-sensitizing agent increases cardiac contractility without altering intracellular Ca(2+) levels and increase in oxygen demand. We present a case of a 51-year-old man, who was suffering from acute right-heart failure in the early postoperative period after heart transplantation. As a rescue therapy at the late stage of a low cardiac output state, levosimendan was started as continuous infusion at 0.1 μg/kg/min for 12 h and thereafter, at 0.2 μg/kg/min for the following 36 h. Levosimendan demonstrated an advanced pharmacological option as was portrayed in this case, where the right ventricle was under a prolonged severe depression and acutely overloaded after heart transplantation.

Distinct loading conditions reveal various patterns of right ventricular adaptation

Right ventricular (RV) failure due to chronically abnormal loading is a main determinant of outcome in pulmonary hypertension (PH) and congenital heart disease. However, distinct types of RV loading have been associated with different outcomes. To determine whether the adaptive RV response depends on loading type, we compared hemodynamics, exercise, and hypertrophy in models of pressure overload due to pulmonary artery banding (PAB), pressure overload due to PH, combined pressure and volume overload, and isolated volume load. Ninety-four rats were subjected to either PAB, monocrotaline-induced PH (PH), aortocaval shunt (shunt), or combined monocrotaline and aortocaval shunt (PH + shunt). We performed pressure-volume analysis and voluntary exercise measurements at 4 wk. We compared PAB to PH (part I) and PH + shunt to either isolated PH or shunt (part II). In part I, enhanced contractility (end-systolic elastance and preload recruitable stroke work) was present in PH and PAB, but strongest in PAB. Frank-Starling mechanism was active in both PAB and PH. In PAB this was accompanied by diastolic dysfunction (increased end-diastolic elastance, relaxation constant), clinical signs of RV failure, and reduced exercise. These distinct responses were not attributable to differences in hypertrophy. In part II, in PH + shunt the contractility response was blunted compared with PH, which caused pseudonormalization of parameters. Additional volume overload strongly enhanced hypertrophy in PH. We conclude that different types of loading result in distinct patterns of RV adaptation. This is of importance for the approach to patients with chronically increased RV load and for experimental studies in various types of RV failure.

Right side of heart failure

The function of the right ventricle (RV) in heart failure (HF) has been mostly ignored until recently. A 2006 report of the National Heart, Lung, and Blood Institute identified a gap between RV research efforts and its clinical importance compared with that of the left ventricle. This recent shift in paradigm is fueled by the prognostic value ascribed to RV failure in HF and morbidity/mortality after myocardial infarction and surgery. In this review, we examine the significance of RV failure in the HF setting, its clinical presentation and pathophysiology, and ways to evaluate RV function using echocardiographic measurements. Furthermore, we discuss the medical management of RV failure including traditional therapies like beta-blockers and newer options like nitric oxide, phosphodiesterase inhibitors, and calcium sensitizers. Mechanical support is also examined. Finally, this review places an emphasis on RV failure in the setting of left ventricular assist devices and heart transplantation.

Intracardiac echocardiography measurement of dynamic myocardial stiffness with shear wave velocimetry

Acoustic radiation force (ARF)-based methods have been demonstrated to be a viable tool for noninvasively estimating tissue elastic properties, and shear wave velocimetry has been used to measure quantitatively the stiffening and relaxation of myocardial tissue in open-chest experiments. Dynamic stiffness metrics may prove to be indicators for certain cardiac diseases, but a clinically viable means of remotely generating and tracking transverse wave propagation in myocardium is needed. Intracardiac echocardiography (ICE) catheter-tip transducers are demonstrated here as a viable tool for making this measurement. ICE probes achieve favorable proximity to the myocardium, enabling the use of shear wave velocimetry from within the right ventricle throughout the cardiac cycle. This article describes the techniques used to overcome the challenges of using a small probe to perform ARF-driven shear-wave velocimetry and presents in vivo porcine data showing the effectiveness of this method in the interventricular septum.