Left ventricular vs. biventricular mechanical support: Decision making and strategies for avoidance of right heart failure after left ventricular assist device implantation

Cardiac Failure and Cardiogenic Shock: Insights Into Pathophysiology, Classification, and Hemodynamic Assessment

Heart failure is defined as increased intracardiac pressures, either alone or combined with reduced cardiac output. Clinically, it is presented with signs and symptoms of congestion and compensated perfusion. Cardiogenic shock, on the other hand, is the spectrum of hemodynamic disturbances that lead to hypoperfusion or need for circulatory support, due to cardiac disease. Both entities affect millions of people worldwide, have a dismal prognosis, and constitute a severe socioeconomic burden. Heart failure can be the aftermath of ischemic heart disease, hypertension, arrhythmias, or cardiomyopathies. It undergoes multiple classifications, facilitating its investigation and treatment. The pathogenetic mechanisms differ in various types of heart failure, regarding the affected ventricles, the duration of symptoms, and their primary/secondary onset. These mechanisms reflect the complex interactions between cardiopulmonary, vascular, and hepatorenal systems. Acute deterioration of cardiac function can lead to cardiogenic shock. Myocardial infarction accounts for 81% of such cases. Healthy lifestyle and timely management of coronary artery disease are paramount, as they can prevent this life-threatening situation and reduce mortality and the economic burden for healthcare systems. Irrespective of the etiology, cardiogenic shock is interpreted using the pressure-volume loop. This can be modified for each ventricle, the underlying pathophysiology, and the time since symptoms' onset. It therefore provides valuable information about the native circulation and the expected alterations under mechanical or pharmacological support, facilitating the decision-making progress. In 2019, given the phenotypical heterogeneity of cardiogenic shock, the Society for Cardiovascular Angiography and Interventions introduced a classification system. According to this, patients are stratified in five stages proportionally to the severity of their condition. Aside from this classification, various biochemical, imaging, and hemodynamic monitoring indices are used to assess coagulation pathway and cardiac, hepatorenal, and pulmonary function, enabling the heart team to tailor therapy. Additionally, the prognostication progress is facilitated by scores, such as the Observatoire Regional Breton sur l'Infarctus (ORBI) score, the intra-aortic balloon pump (IABP) SHOCK-II score, and the CardShock score, indicating suitable escalation or de-escalation strategies. Despite the current progress, there are several areas of advancement regarding the role of vasoactive drugs in cardiogenic shock, revascularization options, mechanical ventilation patterns, hypothermia treatment, and mechanical circulatory support protocols.

Anesthetic management for non-cardiac surgery in patients with left ventricular assist devices

With the growing number of patients undergoing left ventricular assist device (LVAD) implantation and improved survival in this population, more patients with LVADs are presenting for various types of non-cardiac surgery. Therefore, anesthesiologists need to understand the physiology and adequately prepare for the perioperative management of this unique patient population. This review addresses perioperative considerations and intraoperative management for the safe and successful management of patients with an LVAD undergoing non-cardiac surgery. Understanding the basic physiology of preload dependency and afterload sensitivity in these patients is essential. The main considerations include a collaborative preoperative multidisciplinary approach, perioperative care aimed at optimizing the intravascular volume and right ventricular function, and maintaining the afterload within recommended ranges for optimal LVAD function.

Right ventricular dysfunction in left ventricular assist device candidates: is it time to change our prospective?

The use of left ventricular assist devices (LVAD) has significantly increased in the last years, trying to offer a therapeutic alternative to heart transplantation, in light also to the significant heart donor shortage compared to the growing advanced heart failure population. Despite technological improvements in the devices, LVAD-related mortality is still fairly high, with right heart failure being one of the predominant predictors. Therefore, many efforts have been made toward a thorough right ventricular (RV) evaluation prior to LVAD implant, considering clinical, laboratory, echocardiographic, and invasive hemodynamic parameters. However, there is high heterogeneity regarding both which predictor is the strongest as well as the relative cut-off values, and a consensus has not been reached yet, increasing the risk of facing patients in which the distinction between good or poor RV function cannot be surely reached. In parallel, due to technological development and availability of mechanical circulatory support of the RV, LVADs are being considered even in patients with suboptimal RV function. The aim of our review is to analyze the current evidence regarding the role of RV function prior to LVAD and its evaluation, pointing out the extreme variability in parameters that are currently assessed and future prospective regarding new diagnostic tools. Finally, we attempt to gather the available information on the therapeutic strategies to use in the peri-operative phase, in order to reduce the incidence of RV failure, especially in patients in which the preoperative evaluation highlighted some conflicting results with regard to ventricular function.

Durability of Tricuspid Valve Repair in Patients Undergoing Left Ventricular Assist Device Implantation

Objectives: Benefits of tricuspid valve repair (TVR) in left ventricular assist device (LVAD) patients have been questioned. High TVR failure rates have been reported. Remaining or recurring TR was found to be a risk factor for right heart failure (RHF). Therefore, we assessed our experience. Methods: Since 12/2010, 195 patients have undergone LVAD implantation in our center. Almost half (n = 94, 48%) received concomitant TVR (LVAD+TVR). These patients were included in our analysis. Echocardiographic and clinical data were assessed. Median follow-up was 2.8 years (7 days-0.6 years). Results were correlated with clinical outcomes. Results: LVAD+TVR patients were 59.8 ± 11.4 years old (89.4% male) and 37.3% were INTERMACS level 1 and 2. Preoperative TR was moderate in 28 and severe in 66 patients. RV function was severely impaired in 61 patients reflected by TAPSE-values of 11.2 ± 2.9 mm (vs. 15.7 ± 3.8 mm in n = 33; p < 0.001). Risk for RHF according to EUROMACS-RHF risk score was high (>4 points) in 60 patients, intermediate (>2-4 points) in 19 and low (0-2 points) in 15. RHF occurred in four patients (4.3%). Mean duration of echocardiographic follow-up was 2.8 ± 2.3 years. None of the patients presented with severe and only five (5.3%) with moderate TR. The vast majority (n = 63) had mild TR, and 26 patients had no/trace TR. Survival at 1, 3 and 5 years was 77.4%, 68.1% and 55.6%, 30-day mortality was 11.7% (n = 11). Heart transplantation was performed in 12 patients (12.8%). Conclusions: Contrary to expectations, concomitant TVR during LVAD implantation may result in excellent repair durability, which appears to be associated with low risk for RHF.

The impact of right ventricular hemodynamics on the performance of a left ventricular assist device in a numerical simulation model

OBJECTIVES

Left ventricular assist devices (LVADs) have been established as alternative to heart transplantation for patients with end-stage heart failure refractory to medical therapy. Right heart failure (RHF) after LVAD implantation is associated with inferior outcome. Its preoperative anticipation may influence the selection between a pure left ventricular and a biventricular device type and, thus, improve outcomes. Reliable algorithms to predict RHF are missing.

METHODS

A numerical model was used for simulation of a cardiovascular circulation. The LVAD was placed as parallel circuit between left ventricle and aorta. In contrast to other studies, the dynamic hydraulic behavior of a pulsatile LVAD was replaced by that of a continuous LVAD. A variety of hemodynamic states was tested mimicking different right heart conditions. Adjustable parameters included heart rate (HR), pulmonary vascular resistance (PVR), tricuspid regurgitation (TR), right ventricular contractility (RVC) and pump speed. Outcome parameters comprised central venous pressure (CVP), mean pulmonary artery pressure (mPAP), cardiac output (CO) and occurrence of suction.

RESULTS

Alteration of HR, PVR, TR, RVC and pump speed resulted in diverse effects on CO, CVP and mPAP, resulting in improvement, impairment or no change of the circulation, depending on the degree of alteration.

CONCLUSIONS

The numerical simulation model allows prediction of circulatory changes and LVAD behaviour following variation of hemodynamic parameters. Such a prediction may be of particular advantage to anticipate RHF after LVAD implantation. It may help preoperatively to choose the appropriate strategy of only left ventricular or both left and right ventricular support.

Efficacy of levosimendan infusion in patients undergoing a left ventricular assist device implant in a propensity score matched analysis of the EUROMACS registry-the Euro LEVO-LVAD study

OBJECTIVES

Early right-sided heart failure (RHF) was seen in 22% of recipients of a left ventricular assist device (LVAD) in the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). However, the optimal treatment of post-LVAD RHF is not well known. Levosimendan has proven to be effective in patients with cardiogenic shock and in those with end-stage heart failure. We sought to evaluate the efficacy of levosimendan on post-LVAD RHF and 30-day and 1-year mortality.

METHODS

The EUROMACS Registry was used to identify adults with mainstream continuous-flow LVAD implants who were treated with preoperative levosimendan compared to a propensity matched control cohort.

RESULTS

In total, 3661 patients received mainstream LVAD, of which 399 (11%) were treated with levosimendan pre-LVAD. Patients given levosimendan had a higher EUROMACS RHF score [4 (2- 5.5) vs 2 (2- 4); P < 0.001], received more right ventricular assist devices (RVAD) [32 (8%) vs 178 (5.5%); P = 0.038] and stayed longer in the intensive care unit post-LVAD implant [19 (8-35) vs 11(5-25); P < 0.001]. Yet, there was no significant difference in the rate of RHF, 30-day, or 1-year mortality. Also, in the matched cohort (357 patients taking levosimendan compared to an average of 622 controls across 20 imputations), we found no evidence for a difference in postoperative severe RHF, RVAD implant rate, length of stay in the intensive care unit or 30-day and 1-year mortality.

CONCLUSIONS

In this analysis of the EUROMACS registry, we found no evidence for an association between levosimendan and early RHF or death, albeit patients taking levosimendan had much higher risk profiles. For a definitive conclusion, a multicentre, randomized study is warranted.

HeartMate 3 Implantation Through Left Atrial e-PTFE Conduit for Restrictive Cardiomyopathy

Restrictive or hypertrophic cardiomyopathy presents a challenge to left ventricular assist device placement because of the small left ventricle cavity. Cases have described inflow cannulation of the HeartWare HVAD by expanded polytetrafluoroethylene conduit through the atrial septum to the left atrium. We applied this technique to an adult man with restrictive cardiomyopathy and pulmonary hypertension using the HeartMate 3, which successfully supported the patient and led to significant reduction in pulmonary artery pressure. He received a transplant 3 months later without complications. For select patients, left atrial conduit for HeartMate 3 inflow is a feasible alternative to conventional apical cannulation.

Aortic valve disorders and left ventricular assist devices

Aortic valve disorders are important considerations in advanced heart failure patients being evaluated for left ventricular assist devices (LVAD) and those on LVAD support. Aortic insufficiency (AI) can be present prior to LVAD implantation or develop de novo during LVAD support. It is usually a progressive disorder and can lead to impaired LVAD effectiveness and heart failure symptoms. Severe AI is associated with worsening hemodynamics, increased hospitalizations, and decreased survival in LVAD patients. Diagnosis is made with echocardiographic, device assessment, and/or catheterization studies. Standard echocardiographic criteria for AI are insufficient for accurate diagnosis of AI severity. Management of pre-existing AI includes aortic repair or replacement at the time of LVAD implant. Management of de novo AI on LVAD support is challenging with increased risks of repeat surgical intervention, and percutaneous techniques including transcatheter aortic valve replacement are assuming greater importance. In this manuscript, we provide a comprehensive approach to contemporary diagnosis and management of aortic valve disorders in the setting of LVAD therapy.

Biventricular circulatory support using single-device and dual-device configurations: Initial pump characterization in simulated heart failure model

Objective

Severe biventricular heart failure (BHF) can be remedied using a biventricular assist device (BVAD). Two devices are currently in development: a universal ventricular assist device (UVAD), which will be able to assist either the left, right, or both ventricles, and a continuous-flow total artificial heart (CFTAH), which replaces the entire heart. In this study, the in vitro hemodynamic performances of two UVADs are compared to a CFTAH acting as a BVAD.

Methods

For this experiment, a biventricular mock circulatory loop utilizes two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA), in conjunction with a dual-output driver, to create heart failure (HF) conditions (left, LHF; right, RHF; biventricular, BHF). Systolic BHF for four different situations were replicated. In each situation, CFTAH and UVAD devices were installed and operated at two distinct speeds, and cannulations for ventricular and atrial connections were evaluated.

Results

Both CFTAH and UVAD setups achieved our recommended hemodynamic criteria. The dual-UVAD arrangement yielded a better atrial balance to alleviate LHF and RHF. For moderate and severe BHF scenarios, CFTAH and dual UVADs both created excellent atrial pressure balance. Conversely, when CFTAH was atrial cannulated for LHF and RHF, the needed atrial pressure balance was not met.

Conclusion

Comprehensive in vitro testing of two different BVAD setups exhibited self-regulation and exceptional pump performance for both (single- and dual-device) BHF support scenarios. For treating moderate and severe BHF, UVAD and CFTAH both functioned well with respect to atrial pressure regulation and cardiac output. Though, the dual-UVAD setup yielded a better atrial pressure balance in all BHF testing scenarios.

Characterization and Development of Universal Ventricular Assist Device: Computational Fluid Dynamics Analysis of Advanced Design

We are developing a universal, advanced ventricular assist device (AVAD) with automatic pressure regulation suitable for both left and right ventricular support. The primary goal of this computational fluid dynamics (CFD) study was to analyze the biventricular performance of the AVAD across its wide range of operating conditions. An AVAD CFD model was created and validated using in vitro hydraulic performance measurements taken over conditions spanning both left ventricular assist device (LVAD) and right ventricular assist device (RVAD) operation. Static pressure taps, placed throughout the pump, were used to validate the CFD results. The CFD model was then used to assess the change in hydraulic performance with varying rotor axial positions and identify potential design improvements. The hydraulic performance was simulated and measured at rotor speeds from 2,300 to 3,600 revolutions/min and flow rates from 2.0 to 8.0 L/min. The CFD-predicted hydraulic pressure rise agreed well with the in vitro measured data, within 6.5% at 2300 rpm and within 3.5% for the higher rotor speeds. The CFD successfully predicted wall static pressures, matching experimental values within 7%. High degree of similarity and circumferential uniformity in the pump's flow fields were observed over the pump operation as an LVAD and an RVAD. A secondary impeller axial clearance reduction resulted in a 10% decrease in peak flow residence time and lower static pressures on the secondary impeller. These lower static pressures suggest a reduction in the upwards rotor forces from the secondary impeller and a desired increase in the pressure sensitivity of the pump. The CFD analyses supported the feasibility of the proposed AVAD's use as an LVAD or an RVAD, over a wide range of operating conditions. The CFD results demonstrated the operability of the pump in providing the desired circumferential flow similarity over the intended range of flow/speed conditions and the intended functionality of the AVAD's automated pressure regulation.

Percutaneous repositioning of Impella RP: the Snare–Manoeuvre–Prolapse technique—a case report

Background

Impella RP (Abiomed, Danvers, MA, USA) is indicated for right ventricular failure after left ventricular assist device insertion or biventricular shock. Once the peel-away sheath is removed, Impella RP repositioning can only be achieved with manual manipulation of the catheter itself. This method does not always accomplish appropriate positioning of the catheter and can result in continued haemodynamic instability.

Case summary

A young male presented to our institution with recurrent ventricular fibrillation and ST-elevation myocardial infarction that underwent emergent coronary intervention but was in progressive cardiogenic shock requiring implantation of Impella 5.0 and Impella RP. After insertion of the right ventricular support, the patient stabilized transiently then became unstable once more, and repeat fluoroscopy demonstrated that the Impella RP had ‘fallen back’ into the right ventricle. Due to continued instability, we improvised a previously undescribed method of repositioning of the Impella RP catheter with the use of a goose-neck snare.

Discussion

The snare–manoeuvre–prolapse method of Impella RP repositioning is a relatively novel approach at the management of Impella RP retrograde migration into the right ventricle and prevents the need for large-bore venous closure and re-access and the use of a new Impella RP catheter while providing rapid improvement of haemodynamics.

When Nothing Goes Right: Risk Factors and Biomarkers of Right Heart Failure after Left Ventricular Assist Device Implantation

Right heart failure (RHF) is a severe complication after left ventricular assist device (LVAD) implantation. The aim of this study was to analyze the incidence, risk factors, and biomarkers for late RHF including the possible superiority of the device and implantation method. This retrospective, single-center study included patients who underwent LVAD implantation between 2014 and 2018. Primary outcome was freedom from RHF over one-year after LVAD implantation; secondary outcomes included pre- and postoperative risk factors and biomarkers for RHF. Of the 145 consecutive patients (HeartMate 3/HVAD: n = 70/75; female: 13.8%), thirty-one patients (21.4%) suffered RHF after a mean LVAD support of median (IQR) 105 (118) days. LVAD implantation method (less invasive: 46.7% vs. 35.1%, p = 0.29) did not differ significantly in patients with or without RHF, whereas the incidence of RHF was lower in HeartMate 3 vs. HVAD patients (12.9% vs. 29.3%, p = 0.016). Multivariate Cox proportional hazard analysis identified HVAD (HR 4.61, 95% CI 1.12-18.98; p = 0.03), early post-op heart rate (HR 0.96, 95% CI 0.93-0.99; p = 0.02), and central venous pressure (CVP) (HR 1.21, 95% CI 1.05-1.39; p = 0.01) as independent risk factors for RHF, but no association of RHF with increased all-cause mortality (HR 1.00, 95% CI 0.99-1.01; p = 0.50) was found. To conclude, HVAD use, lower heart rate, and higher CVP early post-op were independent risk factors for RHF following LVAD implantation.

Development of tricuspid regurgitation and right ventricular performance after implantation of centrifugal left ventricular assist devices

Background

Tricuspid regurgitation (TR) after left ventricular assist device (LVAD) implantation is associated with a poor prognosis. This study evaluates the development of TR and right ventricular (RV) performance after LVAD implantation.

Methods

Retrospective analysis of patients who underwent LVAD implantation between March 2018 and June 2019. Patients who underwent concomitant tricuspid valve surgery and patients with congenital heart disease were excluded.

Results

A total of 155 patients underwent LVAD implantation. Fourteen patients were excluded. Of the remaining patients, thirty-one died during the first six months, six were lost to follow-up and two underwent transplantation. 102 patients presented at 6.3 months (5.8 to 7.0). Patients were supported with HeartWare HVAD (74%) or HeartMate 3 (26%). 50.4% were rated as INTERMACS profile 1 or 2. At six months, systolic pulmonary artery pressure dropped from 36 to 21 mmHg (P<0.001). Tricuspid annular plane systolic excursion decreased from 17.3 to 14.3 mm (P<0.001), RV fractional area change did not change (P=0.839). Twenty-two patients (22%) presented with moderate-to-severe or severe (ms-s) TR pre-operatively. Of these, eighteen (81%) showed improvement to ≤ moderate TR. At follow-up twelve patients presented with ms-s TR. Of these, only four patients (33%) had been diagnosed with ms-s TR pre-operatively. There were no differences in pre-operative echocardiographic or clinical parameters between the twelve patients with ms-s late TR and the other ninety patients in the cohort.

Conclusions

TR can show an impressive improvement with LVAD support. Longitudinal RV function decreases; this appears to be compensated by transverse shortening. Late TR can develop independently from pre-operative parameters including TR.

2020 EACTS/ELSO/STS/AATS Expert Consensus on Post-cardiotomy Extracorporeal Life Support in Adult Patients

Post-cardiotomy extracorporeal life support (PC-ECLS) in adult patients has been used only rarely but recent data have shown a remarkable increase in its use, almost certainly due to improved technology, ease of management, growing familiarity with its capability and decreased costs. Trends in worldwide in-hospital survival, however, rather than improving, have shown a decline in some experiences, likely due to increased use in more complex, critically ill patients rather than to suboptimal management. Nevertheless, PC-ECLS is proving to be a valuable resource for temporary cardiocirculatory and respiratory support in patients who would otherwise most likely die. Because a comprehensive review of PC-ECLS might be of use for the practitioner, and possibly improve patient management in this setting, the authors have attempted to create a concise, comprehensive and relevant analysis of all aspects related to PC-ECLS, with a particular emphasis on indications, technique, management and avoidance of complications, appraisal of new approaches and ethics, education and training.

Left ventricular assist device inflow cannula implantation: Why a "Step sideways" technique can be helpful

Preservation of right ventricle vascularization that is dependent on left coronary network collateral development is essential during left ventricular assist device implantation to avoid postoperative right heart failure. Our technique was performed on a patient who underwent implantation as a bridge to transplantation; the technique is characterized by providing a moderate lateral and inferior displacement of the inflow cannula position, which achieves both the objectives of respecting the apical course of a left anterior descending coronary artery supplying an occluded right coronary and of maintaining a sufficient orientation degree toward the plane of the mitral valve for correct left ventricular unloading.

2020 EACTS/ELSO/STS/AATS expert consensus on post-cardiotomy extracorporeal life support in adult patients

Post-cardiotomy extracorporeal life support (PC-ECLS) in adult patients has been used only rarely but recent data have shown a remarkable increase in its use, almost certainly due to improved technology, ease of management, growing familiarity with its capability and decreased costs. Trends in worldwide in-hospital survival, however, rather than improving, have shown a decline in some experiences, likely due to increased use in more complex, critically ill patients rather than to suboptimal management. Nevertheless, PC-ECLS is proving to be a valuable resource for temporary cardiocirculatory and respiratory support in patients who would otherwise most likely die. Because a comprehensive review of PC-ECLS might be of use for the practitioner, and possibly improve patient management in this setting, the authors have attempted to create a concise, comprehensive and relevant analysis of all aspects related to PC-ECLS, with a particular emphasis on indications, technique, management, and avoidance of complications, appraisal of new approaches and ethics, education, and training.

Anesthetic Considerations in a Patient With LVAD and COVID-19 Undergoing Video-Assisted Thoracic Surgery

Increased survival with left ventricular assist devices (LVAD) has led to a large number of patients with LVADs presenting for noncardiac surgeries (NCS). With studies showing that a trained noncardiac anesthesiologist can safely manage these patients when they present for NCS, it is vital that all anesthesiologists understand the LVAD physiology and its implications in various surgeries. This is even more relevant during the current pandemic in which these complex cardiopulmonary interactions may be even more challenging in patients with coronavirus disease 2019 (COVID-19). The authors describe a case of a patient with COVID-19 with an LVAD who needed thoracoscopic decortication for recurrent complex pleural effusion and briefly discuss unique challenges presented and their management.

Right Ventricular Failure

Interest in the right ventricle has increased because of advances in pulmonary hypertension treatment, improved diagnostic technology, and increased implantation of left ventricular assist devices and other mechanical circulatory assist devices. Right ventricular dysfunction is an independent predictor of mortality in patients with chronic heart failure. The purpose of this article is to describe the normal structure and function of the right ventricle, causes of right ventricular dysfunction leading to right ventricular failure, diagnostic hemodynamic assessments, and management of right ventricular failure in the critical care unit.

Ventricular systolic dysfunction with and without altered myocardial contractility: Clinical value of echocardiography for diagnosis and therapeutic decision-making

The inability of one of the two or both ventricles to contract normally and expel sufficient blood to meet the functional demands of the body results from a complex interplay between intrinsic abnormalities and extracardiac factors that limit ventricular pump function and is a major cause for heart failure (HF). Even if impaired myocardial contractile function was the primary cause for ventricular dysfunction, with the progression of systolic dysfunction, additionally developed diastolic dysfunction can also contribute to the severity of HF. Although at the first sight, the diagnosis of systolic HF appears quite easy because it is usually defined by reduction of the ejection fraction (EF), in reality this issue is far more complex because ventricular pumping performance depends not only on myocardial contractility, but also largely on loading conditions (preload and afterload), being also influenced by valvular function, ventricular interdependence, pericardial constraint, synchrony of ventricular contrac-tion and heart rhythm. Conventional echocardiography (ECHO) combined with new imaging techniques such as tissue Doppler and tissue tracking can detect early subclinical alteration of ventricular systolic function. However, no single ECHO parameter reveals alone the whole picture of systolic dysfunction. Multiparametric ECHO evaluation and the use of integrative approaches using ECHO-parameter combinations which include also the ventricular loading conditions appeared particularly useful especially for differentiation between primary (myocardial damage-induced) and secondary (hemodynamic overload-induced) systolic dysfunction. This review summarizes the available evidence on the usefulness and limitations of comprehensive evaluation of LV and RV systolic function by using all the currently available ECHO techniques.

Modeling of Virtual Mechanical Circulatory Hemodynamics for Biventricular Heart Failure Support

OBJECTIVE

In this study, a mechanical circulatory support simulation tool was used to investigate the application of a unique device with two centrifugal pumps and one motor for the biventricular assist device (BVAD) support application. Several conditions-including a range of combined left and right systolic heart failure severities, aortic and pulmonary valve regurgitation, and combinations of high and low systemic and pulmonary vascular resistances-were considered in the simulation matrix. Relative advantages and limitations of using the device in BVAD applications are discussed.

METHODS

The simulated BVAD pump was based on the Cleveland Clinic pediatric continuous-flow total artificial heart (P-CFTAH), which is currently under development. Different combined disease states (n = 10) were evaluated to model the interaction with the BVAD, considering combinations of normal heart, moderate failure and severe systolic failure of the left and right ventricles, regurgitation of the aortic and pulmonary valves and combinations of vascular resistance. The virtual mock loop simulation tool (MATLAB; MathWorks®, Natick, MA) simulates the hemodynamics at the pump ports using a lumped-parameter model for systemic/pulmonary circulation characteristic inputs (values for impedance, systolic and diastolic ventricular compliance, beat rate, and blood volume), and characteristics of the cardiac chambers and valves.

RESULTS

Simulation results showed that this single-pump BVAD can provide regulated support of up to 5 L/min over a range of combined heart failure states and is suitable for smaller adult and pediatric support. However, good self-regulation of the atrial pressure difference was not maintained with the introduction of aortic valve regurgitation or high systemic vascular resistance when combined with low pulmonary vascular resistance.

CONCLUSIONS

This initial in silico study demonstrated that use of the P-CFTAH as a BVAD supports cardiac output and arterial pressure in biventricular heart failure conditions. A similar but larger device would be required for a large adult patient who needs more than 5 L/min of support.

Characterization of a pulsatile rotary total artificial heart

This article describes the properties and performance of a rotary total artificial heart (TAH) that produces inherently pulsatile flow. The hydraulic performance of the TAH was characterized using a mock circulatory loop to simulate four physiologically relevant conditions: baseline flow, increased flow, systemic hypertension, and pulmonary hypertension. The pump has a variable shuttle rate (beats per minute), percentage dwell time, and angular velocity on either side (revolutions per minute), which allows for full control of the flow rate and pulsatility over a range of healthy and pathologic pressures and flow rates. The end-to-end length and displacement volume of the TAH are 9.8 cm and 130 mL, respectively, allowing it to fit in smaller chest cavities including those of smaller adults and juvenile humans.

2020 EACTS/ELSO/STS/AATS expert consensus on post-cardiotomy extracorporeal life support in adult patients

Post-cardiotomy extracorporeal life support (PC-ECLS) in adult patients has been used only rarely but recent data have shown a remarkable increase in its use, almost certainly due to improved technology, ease of management, growing familiarity with its capability and decreased costs. Trends in worldwide in-hospital survival, however, rather than improving, have shown a decline in some experiences, likely due to increased use in more complex, critically ill patients rather than to suboptimal management. Nevertheless, PC-ECLS is proving to be a valuable resource for temporary cardiocirculatory and respiratory support in patients who would otherwise most likely die. Because a comprehensive review of PC-ECLS might be of use for the practitioner, and possibly improve patient management in this setting, the authors have attempted to create a concise, comprehensive and relevant analysis of all aspects related to PC-ECLS, with a particular emphasis on indications, technique, management and avoidance of complications, appraisal of new approaches and ethics, education and training.

2020 EACTS/ELSO/STS/AATS Expert Consensus on Post-Cardiotomy Extracorporeal Life Support in Adult Patients

Post-cardiotomy extracorporeal life support (PC-ECLS) in adult patients has been used only rarely but recent data have shown a remarkable increase in its use, almost certainly due to improved technology, ease of management, growing familiarity with its capability and decreased costs. Trends in worldwide in-hospital survival, however, rather than improving, have shown a decline in some experiences, likely due to increased use in more complex, critically ill patients rather than to suboptimal management. Nevertheless, PC-ECLS is proving to be a valuable resource for temporary cardiocirculatory and respiratory support in patients who would otherwise most likely die. Because a comprehensive review of PC-ECLS might be of use for the practitioner, and possibly improve patient management in this setting, the authors have attempted to create a concise, comprehensive and relevant analysis of all aspects related to PC-ECLS, with a particular emphasis on indications, technique, management and avoidance of complications, appraisal of new approaches and ethics, education and training.

Current perspectives on mechanical circulatory support

Mechanical circulatory support gained a significant value in the armamentarium of heart failure therapy because of the increased awareness of the prevalence of heart failure and the tremendous advances in the field of mechanical circulatory support during the last decades. Current device technologies already complement a heart transplant as the gold standard of treatment for patients with end-stage heart failure refractory to conservative medical therapy. This article reviews important aspects of mechanical circulatory support therapy and focuses on currently debated issues.

Effect of left ventricular assist device implantation on right ventricular function: Assessment based on right ventricular pressure-volume curves

Right ventricular (RV) failure is significantly associated with morbidity and mortality after left ventricular assist device (LVAD) implantation. However, it remains unclear whether LVAD implantation could worsen RV function. Therefore, we aimed to investigate the effect of LVAD implantation on RV function by comparing RV energetics derived from the RV pressure-volume curve between before and after LVAD implantation. This exploratory observational study was performed between September 2016 and January 2018 at a national center in Japan. Twenty-two patients who underwent LVAD implantation were included in the analysis. We measured RV energetics parameters: RV stroke work index (RVSWI), which was calculated by integrating the area within the RV pressure-volume curve; RV minute work index (RVMWI), which was calculated as RVSWI × heart rate; and right ventriculo-arterial coupling, which was estimated as RV stroke volume/RV end-systolic volume. We compared RV energetics between before and after LVAD implantation. Although RVSWI was similar [424.4 mm Hg · mL/m² (269.5-510.3) vs. 379.9 mm Hg · mL/m² (313.1-608.8), P = 0.485], RVMWI was significantly higher after LVAD implantation [29 834.1 mm Hg · mL/m² /min (18 272.2-36 357.1) vs. 38 544.8 mm Hg · mL/m² /min (29 016.0-57 282.8), P = 0.001], corresponding to a significantly higher cardiac index [2.0 L/min/m² (1.4-2.2) vs. 3.7 L/min/m² (3.3-4.1), P < 0.001] to match LVAD flow. Right ventriculo-arterial coupling was significantly higher after LVAD implantation [0.360 (0.224-0.506) vs. 0.480 (0.343-0.669), P = 0.025], suggesting that the efficiency of RV performance improved. In conclusion, higher RVMWI with higher cardiac index to match LVAD flow and improved efficiency of RV performance indicate that LVAD implantation might not worsen RV function.

The left atrium and the right ventricle: two supporting chambers to the failing left ventricle

Heart failure (HF) is mainly caused by left ventricular (LV) impairment of function, hence detailed assessment of its structure and function is a clinical priority. The frequent involvement of the left atrium (LA) and the right ventricle (RV) in the overall cardiac performance has recently gained significant interest with specific markers predicting exercise intolerance and prognosis being proposed. The LA and RV are not anatomically separated from the LV, while the LA controls the inlet the RV shares the interventricular septum with the LV. Likewise, the function of the two chambers is not entirely independent from that of the LV, with the LA enlarging to accommodate any rise in filling pressures, which could get transferred to the RV via the pulmonary circulation. In the absence of pulmonary disease, LA and RV function may become impaired in patients with moderate-severe LV disease and raised filling pressures. These changes can often occur irrespective of the severity of systolic dysfunction, thus highlighting the important need for critical assessment of the function of the two chambers. This review evaluates the pivotal role of the left atrium and right ventricle in the management of HF patients based on the available evidence.

First In Vivo Experience With Biventricular Circulatory Assistance Using a Single Continuous Flow Pump

Biventricular assist device (BVAD) implantation is the treatment of choice in patients with severe biventricular heart failure and cardiogenic shock. Our team has developed a miniaturized continuous flow, double-ended centrifugal pump intended for total artificial heart implant (CFTAH). The purpose of this initial in vivo study was to demonstrate that the scaled-down CFTAH (P-CFTAH) can be appropriate for BVAD support. The P-CFTAH was implanted in 4 acute lambs (average weight, 41.5 ± 2.8 kg) through a median sternotomy. The cannulation was performed through the left and right atria, and cannulae length adjustment was performed for atrial and ventricular cannulation. The BVAD system was tested at 3 pump speeds (3000, 4500, and 6000 rpm). The BVAD performed very well for both atrial and ventricular cannulation within the 3000-6000 rpm range. Stable hemodynamics were maintained after implantation of the P-CFTAH. The self-regulating performance of the system in vivo was demonstrated by the left (LAP) and right (RAP) pressure difference (LAP-RAP) falling predominantly within the range of -5 to 10 mm Hg with variation, in addition to in vitro assessment of left and right heart failure conditions. Left and right pump flows and total flow increased as the BVAD speed was increased. This initial in vivo testing of the BVAD system demonstrated satisfactory device performance and self-regulation for biventricular heart failure support over a wide range of conditions. The BVAD system keeps the atrial pressure difference within bounds and maintains acceptable cardiac output over a wide range of hemodynamic conditions.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: part 1-Adult patients

Cardiogenic shock, cardiac arrest, acute respiratory failure, or a combination of such events, are all potential complications after cardiac surgery which lead to high mortality. Use of extracorporeal temporary cardio-circulatory and respiratory support for progressive clinical deterioration can facilitate bridging the patient to recovery or to more durable support. Over the last decade, extracorporeal membrane oxygenation (ECMO) has emerged as the preferred temporary artificial support system in such circumstances. Many factors have contributed to widespread ECMO use, including the relative ease of implantation, effectiveness, versatility, low cost relative to alternative devices, and potential for full, not just partial circulatory support. While there have been numerous publications detailing the short and midterm outcomes of ECMO support, specific reports about post-cardiotomy ECMO (PC-ECMO), are limited, single-center experiences. Etiology of cardiorespiratory failure leading to ECMO implantation, associated ECMO complications, and overall patient outcomes may be unique to the PC-ECMO population. Despite the rise in PC-ECMO use over the past decade, short-term survival has not improved. This report, therefore, aims to present a comprehensive overview of the literature with respect to the prevalence of ECMO use, patient characteristics, ECMO management, and in-hospital and early post-discharge patient outcomes for those treated for post-cardiotomy heart, lung, or heart-lung failure.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

Facilitating noncardiac surgery for the patient with left ventricular assist device: A guide for the anesthesiologist

The introduction of left ventricular assist device (LVAD) has improved survival rates for patients with end-stage heart failure. Two categories of VADs exist: one generates pulsatile flow and the other produces nonpulsatile continuous flow. Survival is better for patients with continuous-flow LVADs. With improved survival, more of such patients now present for noncardiac surgery (NCS). This review, written for the general anesthesiologists, addresses the perioperative considerations when the patient undergoes NCS. For best outcomes, a multidisciplinary approach is essential in perioperative management of the patient.

Predictors and impact of right heart failure severity following left ventricular assist device implantation

Background

Right heart failure (RHF) is a well-known consequence of left ventricular assist device (LVAD) placement, and has been linked to negative surgical outcomes. However, little is known regarding risk factors associated with RHF. This article delineates pre- and intra-operative risk factors for RHF following LVAD implantation and demonstrates the effect of RHF severity on key surgical outcomes.

Methods

We performed a retrospective analysis of consecutive LVAD patients treated at our center between 2008 and 2016. RHF was categorized using the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definition of none/mild, moderate, severe, and acute-severe. We constructed a predictive model using multivariable logistic regression and performed a competing risks analysis for survival stratified by RHF severity.

Results

Of 202 subjects, 52 (25.7%) developed moderate or worse RHF. Cardiopulmonary bypass (CPB) time and nadir hematocrit contributed jointly to the model of RHF severity (moderate or worse vs. none/mild; area under the curve =0.77). Postoperative length of stay (LOS) was shortest in the non/mild group and longest in the acute-severe group (median 13 vs. 29.5 days; P<0.001). Stage 2/3 acute kidney injury (range, 26-57%, P=0.002), respiratory failure (13-94%, P<0.001), stroke (0-32%, P=0.02), and 1-year mortality (19-64%, P=0.002) differed by severity. Those with acute-severe RHF had 5.4 [95% confidence interval (CI), 2.5-11.8] times the risk of 1-year mortality compared to those who did not have RHF.

Conclusions

RHF remains a postoperative threat and is associated with worsened surgical outcomes. Ongoing research will reveal further opportunities to mitigate RHF post-LVAD.

Temporary assist device support for the right ventricle: pre-implant and post-implant challenges

Severe right ventricular (RV) failure is more likely reversible than similar magnitudes of left ventricular (LV) failure and, because reversal of both adaptive remodeling and impaired contractility require most often only short periods of support, the use of temporary RV assist devices (t-RVADs) can be a life-saving therapy option for many patients. Although increased experience with t-RVADs and progresses made in the development of safer devices with lower risk for complications has improved both recovery rate of RV function and patient survival, the mortality of t-RVAD recipients can still be high but it depends mainly on the primary cause of RV failure (RVF), the severity of end-organ dysfunction, and the timing of RVAD implantation, and much less on adverse events and complications related to RVAD implantation, support, or removal. Reduced survival of RVAD recipients should therefore not discourage appropriate application of RVADs because their underuse further reduces the chances for RV recovery and patient survival. The article reviews and discusses the challenges related to the pre-implant and post-implant decision-making processes aiming to get best possible therapeutic results. Special attention is focused on pre-implant RV assessment and prediction of RV improvement during mechanical unloading, patient selection for t-RVAD therapy, assessment of unloading-promoted RV recovery, and prediction of its stability after RVAD removal. Particular consideration is also given to prediction of RVF after LVAD implantation which is usually hampered by the complex interactions between the different risk factors related indirectly or directly to the RV potential for reverse remodeling and functional recovery.

Temporary mechanical circulatory support for refractory heart failure: the German Heart Center Berlin experience

Background

Temporary mechanical circulatory support (MCS) offers a valuable option for treatment of refractory heart failure. We present our experience with selected MCS devices in cardiogenic shock of different etiologies.

Methods

We retrospectively studied patients who were treated in our institution between 01/2016 and 07/2018. Patients receiving only veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support were excluded. Left ventricular support patients received Impella; right ventricular support was conducted using Levitronix CentriMag.

Results

Thirty-seven patients received an Impella left ventricular assist device (LVAD). Etiology was: acute on chronic ischemic cardiomyopathy (ICMP; n=12), acute myocardial infarction (AMI; n=11), dilated cardiomyopathy (DCMP; n=7) and toxic cardiomyopathy (TCMP; n=2). Two patients presented with postcardiotomy shock and acute myocarditis, respectively. In one case, Takotsubo cardiomyopathy was diagnosed. Impella was used solely in 28 patients (Impella group) with an in-hospital survival of 37%. In nine patients, Impella was used in combination with extracorporeal life support (ECLS) implantation (ECMELLA group)-in-hospital survival was 33%. In the Impella group six patients recovered, six received a long-term VAD and 16 died on device. In the ECMELLA group one patient recovered, three received a long-term VAD and five died. The majority of CentriMag implantations as a right ventricular assist device (RVAD) were necessary after LVAD implantation (n=52); of these patients, 14 recovered, eight received long-term VAD and 30 died. The remaining 17 patients were supported by RVAD due to AMI (n=7); postcardiotomy (n=7); right heart failure after heart transplantation (n=2) and ICMP (n=1). Six of these patients recovered, two required long-term VAD and nine died.

Conclusions

Survival after MCS implantation for left as well as right heart failure in cardiogenic shock remains low, but is superior to that of patients without mechanical support. Short-term MCS remains an option of choice if right, left or biventricular support is needed.

Role of multimodality imaging in patients with left ventricular assist device

PURPOSE OF REVIEW

The article provides an overview of recent advances in imaging patients with a left ventricular assist device (LVAD).

RECENT FINDINGS

There is a growing population of patients with LVADs. LVADs improve survival in patients with end-stage heart failure, but are also associated with significant adverse outcomes. Imaging, particularly echocardiography, plays a critical role in patient selection and in predicting and detecting complications.

SUMMARY

Recent studies have illustrated links between imaging parameters with adverse outcomes, such as pump thrombosis, right ventricular failure, and continuous aortic regurgitation. Novel parameters and imaging techniques have been developed.

Evaluation of the right ventricle by echocardiography: particularities and major challenges

INTRODUCTION

Compared with the left ventricle (LV), the right ventricle (RV) is less suited for evaluation by echocardiography (ECHO). Nevertheless, RV ECHO-assessment has currently emerged as an important diagnostic tool with meaningful prognostic value and essential contribution to therapeutic decisions. Although significant progress has been made, including generation of higher-quality normative data, validation of several two-dimensional measurements and improvements in three-dimensional ECHO-techniques, many challenges in RV ECHO-assessment still persist. Areas covered: This review discusses the particular challenges and limits in obtaining accurate measurements of RV anatomical and functional parameters and focuses primarily on the difficulties in proper interpretation of the highly load dependent RV ECHO-parameters which complicates the use of this valuable diagnostic and surveillance technique. Expert commentary: There is increasing evidence that RV assessment in relation with its actual loading conditions by ECHO-derived composite variables, which either incorporate a certain functional parameter and load, or incorporate measures which reflect the relationship between RV dilation and RV load, considering also the right atrial pressure (i.e. 'load adaptation index'), is particularly suited for clinical decision-making. Load dependency of RV ECHO-parameters must be taken into consideration especially in patients with advanced RV dysfunction scheduled for LV assist device implantation or lung transplantation.

Derivation and Validation of a Novel Right-Sided Heart Failure Model After Implantation of Continuous Flow Left Ventricular Assist Devices

Background:

The aim of the study was to derive and validate a novel risk score for early right-sided heart failure (RHF) after left ventricular assist device implantation.

Methods:

The EUROMACS (European Registry for Patients with Mechanical Circulatory Support) was used to identify adult patients undergoing continuous-flow left ventricular assist device implantation with mainstream devices. Eligible patients (n=2988) were randomly divided into derivation (n=2000) and validation (n=988) cohorts. The primary outcome was early (<30 days) severe postoperative RHF, defined as receiving short- or long-term right-sided circulatory support, continuous inotropic support for ≥14 days, or nitric oxide ventilation for ≥48 hours. The secondary outcome was all-cause mortality and length of stay in the intensive care unit. Covariates found to be associated with RHF (exploratory univariate P <0.10) were entered into a multivariable logistic regression model. A risk score was then generated using the relative magnitude of the exponential regression model coefficients of independent predictors at the last step after checking for collinearity, likelihood ratio test, c index, and clinical weight at each step.

Results:

A 9.5-point risk score incorporating 5 variables (Interagency Registry for Mechanically Assisted Circulatory Support class, use of multiple inotropes, severe right ventricular dysfunction on echocardiography, ratio of right atrial/pulmonary capillary wedge pressure, hemoglobin) was created. The mean scores in the derivation and validation cohorts were 2.7±1.9 and 2.6±2.0, respectively ( P =0.32). RHF in the derivation cohort occurred in 433 patients (21.7%) after left ventricular assist device implantation and was associated with a lower 1-year (53% versus 71%; P <0.001) and 2-year (45% versus 58%; P <0.001) survival compared with patients without RHF. RHF risk ranged from 11% (low risk score 0–2) to 43.1% (high risk score >4; P <0.0001). Median intensive care unit stay was 7 days (interquartile range, 4–15 days) versus 24 days (interquartile range, 14–38 days) in patients without versus with RHF, respectively ( P <0.001). The c index of the composite score was 0.70 in the derivation and 0.67 in the validation cohort. The EUROMACS-RHF risk score outperformed ( P <0.0001) previously published scores and known individual echocardiographic and hemodynamic markers of RHF.

Conclusions:

This novel EUROMACS-RHF risk score outperformed currently known risk scores and clinical predictors of early postoperative RHF. This novel score may be useful for tailored risk-based clinical assessment and management of patients with advanced HF evaluated for ventricular assist device therapy.

Implantation of Short-Term and Long-Term Right Ventricular Assist Devices

The last decade has seen considerable growth in the use of left ventricular assist devices (LVAD), in end-phase heart failure treatment. The indications, contraindications and implantation techniques are well-defined. However, information about mechanical support for right ventricular failure is lacking. The aim of this communication is to present alternative techniques for implantation of short- and longterm right ventricular assist devices. Implanting the device in the right atrium has certain advantages when compared with the right ventricle. It is an easier surgical technique that preserves the tricuspid valve and it can potentially reduce the risk of pump thrombosis.

CPR, ECLS, BVAD and successful heart transplantation within 2 months: a single-centre case series in two young, high-urgency listed patients

INTRODUCTION

In times of organ shortage, death while on the heart waiting-list still represents a major problem. As a consequence, bridging to transplant as well as the decision when to escalate therapy play a very important role.

METHODS AND RESULTS

We report on two young patients with dilated cardiomyopathy and acute decompensation who were successfully bridged to heart transplantation with both left and temporary right ventricular assist devices in just 2 months.

CONCLUSIONS

As a permanent biventricular assist device (BVAD) would have definitely impaired the patients' outcome after HTX, we decided to implant an LVAD with a temporary RVAD. In our opinion, this represents a suitable strategy to reduce mortality in HU-listed patients with acute deterioration of cardiac pump function and should be further evaluated in future studies.

Three-Dimensional Echocardiography-Derived Non-Invasive Right Ventricular Pressure-Volume Analysis

In patients with pulmonary hypertension, repeated evaluations of right ventricular (RV) function are still required for clinical decision making, but the invasive nature of current pressure-volume analysis makes conducting regular follow-ups in a clinical setting infeasible. We enrolled 12 patients with pulmonary arterial hypertension (PAH) and 10 with pulmonary venous hypertension (PVH) May 2016-October 2016. All patients underwent a clinically indicated right heart catheterization (RHC), from which the yielded right ventricular pressure recordings were conjugated with RV volume by 3-D echocardiography to generate a pressure-volume loop. A continuous-wave Doppler envelope of tricuspid regurgitation was transformed into a pressure gradient recording by the simplified Bernoulli equation, and then a systolic pressure gradient-volume (PG-V) diagram was generated from similar methods. The area enclosed by the pressure-volume loop was calculated to represent semi-invasive right ventricular stroke work (RVSW_RHC). The area between the PG-V diagram and x-axis was calculated to estimate non-invasive RVSW (RVSW_echo). Patients with PAH have higher RV pressure, lower pulmonary arterial wedge pressure and larger RV volume that was contributed by the dilation of RV mid-cavity minor dimension. We found no significant difference of traditional parameters between these two groups, but RVSW values were significantly higher in PAH patients. The RVSW values of these two methods were significantly correlated by the equation RVSW_echo = 0.8447 RVSW_RHC + 129.38 (R² = 0.9151, p < 0.001). The linearity remained satisfactory in both groups. We conclude that a PG-V diagram is a reliable method to estimate RVSW and to depict pathophysiological status.

Perioperative Care of the Patient With the Total Artificial Heart

Advanced heart failure continues to be a leading cause of morbidity and mortality despite improvements in pharmacologic therapy. High demand for cardiac transplantation and shortage of donor organs have led to an increase in the utilization of mechanical circulatory support devices. The total artificial heart is an effective biventricular assist device that may be used as a bridge to transplant and that is being studied for destination therapy. This review discusses the history, indications, and perioperative management of the total artificial heart with emphasis on the postoperative concerns.

Added clinical value of applying myocardial deformation imaging to assess right ventricular function

Right heart dysfunction has been found to be a strong prognostic factor predicting adverse outcome in various cardiopulmonary diseases. Conventional echocardiographic measurements can be limited by geometrical assumptions and impaired reproducibility. Speckle tracking-derived strain provides a robust quantification of right ventricular function. It explicitly evaluates myocardial deformation, as opposed to tissue Doppler-derived strain, which is computed from tissue velocity gradients. Right ventricular longitudinal strain provides a sensitive tool for detecting right ventricular dysfunction, even at subclinical levels. Moreover, the longitudinal strain can be applied for prognostic stratification of patients with pulmonary hypertension, pulmonary embolism, and congestive heart failure. Speckle tracking-derived right atrial strain, right ventricular longitudinal strain-derived mechanical dyssynchrony, and three-dimensional echocardiography-derived strain are emerging imaging parameters and methods. Their application in research is paving the way for their clinical use.

Cardiac passive-aggressive behavior? The right ventricle in patients with a left ventricular assist device

INTRODUCTION

Right ventricular failure (RVF) affects up to 50% of patients post-left ventricular assist device (LVAD) implantation, and carries significant morbidity and mortality. There is no widely-used long-term mechanical support option for the right ventricle, thus early identification, prevention and medical treatment of RVF is of the upmost importance. Areas covered: A PubMed search was first completed searching 'Right ventricular failure post-LVAD' which yielded 152 results, and a subsequent search was performed under 'RV mechanical support' which yielded 374 results, and was filtered to 'humans' and literature written in English, generating 219 results. We focused this research on pre-operative risk factors identified in the literature for developing RVF-post LVAD implantation, and the medical and surgical treatment options for RVF, including mechanical treatment options. Expert commentary: There is little consensus on pre-operative risk factors that reliably predict RVF post-LVAD implantation. Large prospective randomized trials would help clarify indications for specific medical and surgical therapy. We gather this knowledge in the present article and describe the main RVF remediation modalities. Surgeons and anesthesiologists should help prevent and have a low threshold for initiating supportive treatment for RVF, which may include increasingly invasive therapies up to long-term mechanical RV support.