Right heart failure and "failure to thrive" after left ventricular assist device: clinical predictors and outcomes

Association between pulmonary artery pulsatility and mortality after implantation of left ventricular assist device

AIMS

Right ventricular failure after left ventricular assist device (LVAD) implantation is a major concern that remains challenging to predict. We sought to investigate the relationship between preoperative pulmonary artery pulsatility index (PAPi) and mortality after LVAD implantation.

METHODS AND RESULTS

A retrospective analysis of the ASSIST-ICD multicentre registry allowed the assessment of PAPi before LVAD according to the formula [(systolic pulmonary artery pressure - diastolic pulmonary artery pressure)/central venous pressure]. The primary endpoint was survival at 3 months, according to the threshold value of PAPi determined by the receiver operating characteristic (ROC) curve. A multivariate analysis including demographic, echographic, haemodynamic, and biological variables was performed to identify predictive factors for 2 year mortality. One hundred seventeen patients were included from 2007 to 2021. The mean age was 58.45 years (±13.16), with 15.4% of women (sex ratio 5.5). A total of 53.4% were implanted as bridge to transplant and 43.1% as destination therapy. Post-operative right ventricular failure was observed in 57 patients (48.7%), with no significant difference between survivors and non-survivors at 1 month (odds ratio 1.59, P = 0.30). The median PAPi for the whole study population was 2.83 [interquartile range 1.63-4.69]. The threshold value of PAPi determined by the ROC curve was 2.84. Patients with PAPi ≥ 2.84 had a higher survival rate at 3 months [PAPi < 2.84: 58.1% [46.3-72.8%] vs. PAPi ≥ 2.84: 89.1% [81.1-97.7%], hazard ratio (HR) 0.08 [0.02-0.28], P < 0.01], with no significant difference after 3 months (HR 0.67 [0.17-2.67], P = 0.57). Other predictors of 2 year mortality were systemic hypertension (HR 4.22 [1.49-11.97], P < 0.01) and diabetes mellitus (HR 4.90 [1.83-13.14], P < 0.01). LVAD implantation as bridge to transplant (HR 0.18 [0.04-0.74], P = 0.02) and heart transplantation (HR 0.02 [0.00-0.18], P < 0.01) were associated with a higher survival rate at 2 years.

CONCLUSIONS

Preoperative PAPi < 2.84 was associated with a higher risk of early mortality after LVAD implantation without impacting 2 year outcomes among survivors.

Inhaled Epoprostenol Compared With Nitric Oxide for Right Ventricular Support After Major Cardiac Surgery

BACKGROUND

Right ventricular failure (RVF) is a leading driver of morbidity and death after major cardiac surgery for advanced heart failure, including orthotopic heart transplantation and left ventricular assist device implantation. Inhaled pulmonary-selective vasodilators, such as inhaled epoprostenol (iEPO) and nitric oxide (iNO), are essential therapeutics for the prevention and medical management of postoperative RVF. However, there is limited evidence from clinical trials to guide agent selection despite the significant cost considerations of iNO therapy.

METHODS

In this double-blind trial, participants were stratified by assigned surgery and key preoperative prognostic features, then randomized to continuously receive either iEPO or iNO beginning at the time of separation from cardiopulmonary bypass with the continuation of treatment into the intensive care unit stay. The primary outcome was the composite RVF rate after both operations, defined after transplantation by the initiation of mechanical circulatory support for isolated RVF, and defined after left ventricular assist device implantation by moderate or severe right heart failure according to criteria from the Interagency Registry for Mechanically Assisted Circulatory Support. An equivalence margin of 15 percentage points was prespecified for between-group RVF risk difference. Secondary postoperative outcomes were assessed for treatment differences and included: mechanical ventilation duration; hospital and intensive care unit length of stay during the index hospitalization; acute kidney injury development including renal replacement therapy initiation; and death at 30 days, 90 days, and 1 year after surgery.

RESULTS

Of 231 randomized participants who met eligibility at the time of surgery, 120 received iEPO, and 111 received iNO. Primary outcome occurred in 30 participants (25.0%) in the iEPO group and 25 participants (22.5%) in the iNO group, for a risk difference of 2.5 percentage points (two one-sided test 90% CI, -6.6% to 11.6%) in support of equivalence. There were no significant between-group differences for any of the measured postoperative secondary outcomes.

CONCLUSIONS

Among patients undergoing major cardiac surgery for advanced heart failure, inhaled pulmonary-selective vasodilator treatment using iEPO was associated with similar risks for RVF development and development of other postoperative secondary outcomes compared with treatment using iNO.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03081052.

Proportion of right ventricular failure and echocardiographic predictors in continuous-flow left ventricular assist device: a systematic review and meta-analysis

Background

Right ventricular failure (RVF) in patients with a continuous-flow left ventricle assist device (CF-LVAD) is associated with higher incidence of mortality. This systematic review aims to assess the overall proportion of RVF and the pre-operative echocardiographic parameters which are best correlating to RVF.

Methods

A systematic research was conducted between 2008 and 2019 on MEDLINE, EMBASE, PUBMED, UPTODATE, OVID, COCHRANE LIBRARY, and Google Scholar electronic databases by performing a PRISMA flowchart. All observational studies regarding echocardiographic predictors of RVF in patients undergoing CF-LVAD implantation were included.

Results

A total number of 19 observational human studies published between 2008 and 2019 were included. We identified 524 RVF patients out of a pooled final population of 1741 patients. The RVF overall proportion was 28.25% with 95% confidence interval (CI) 0.24-0.34. The highest variability of perioperative echocardiographic parameters between the RVF and no right ventricular failure (NO-RVF) groups has been found with tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and right ventricular global longitudinal strain (RVGLS). Their standardized mean deviation (SMD) was - 0.33 (95% CI - 0.54 to - 0.11; p value 0.003), - 0.34 (95% CI - 0.53 to - 0.15; p value 0.0001), and 0.52 (95% CI 0.79 to 0.25; p value 0.0001), respectively.

Conclusions

The echocardiographic predictors of RVF after CF-LVAD placement are still uncertain. However, there seems to be a trend of statistical correlation between TAPSE, FAC, and RVGLS with RVF event after CF-LVAD placement.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01447-7.

A novel metrics to predict right heart failure after left ventricular assist device implantation

BACKGROUND

Right Heart Failure (RHF) is a severe complication that can occur after left ventricular assist device (LVAD) implantation, increasing early and late mortality. Although numerous RHF predictive scores have been developed, limited data exist on the external validation of these models. We therefore aimed at comparing existent risk score models and identifying predictors of severe RHF at our center.

METHODS

In this retrospective, single-center analysis, clinical, biological and functional data were collected in patients implanted with a LVAD between 2011 and 2020. Early severe RHF was defined as the use of inotropes for ≥ 14 days, nitric oxide use for ≥ 48 h or unplanned right-sided circulatory support. Risk models were evaluated for the primary outcome of RHF or RVAD implantation by means of logistic regression and receiver operating characteristic curves.

RESULTS

Among 92 patients implanted, 24 (26%) developed early severe RHF. The EUROMACS-RHF risk score performed the best in predicting RHF (C = 0.82-95% CI: 0.68-0.90), compared with the other scores (Michigan, CRITT). In addition, we developed a new model, based on four variables selected for the best reduced logistic model: the INTERMACS level, the number of inotropes used, the ratio of right atrial/pulmonary capillary wedge pressure and the ratio of right ventricle/left ventricle diameters by echocardiography. This model demonstrated significant discrimination of RHF (C = 0.9-95% CI: 0.76-0.96).

CONCLUSION

Amongst available risk scores, EUROMACS-RHF performs best to predict the occurrence of RHF after LVAD implantation. Our model's performance compares well to the EUROMACS-RHF score, adding a more objective parameter to RV function evaluation.

Impact of Right Heart Failure on Clinical Outcome of Left Ventricular Assist Devices (LVAD) Implantation: Single Center Experience

The aim of this study was to examine the incidence and significance of right heart failure (RHF) in the early and late phase of left ventricular assist device (LVAD) implantation with the identification of predictive factors for the development of RHF. This was a prospective observational analytical cohort study. The study included 92 patients who underwent LVAD implantation and for whom all necessary clinical data from the follow-up period were available, as well as unambiguous conclusions by the heart team regarding pathologies, adverse events, and complications. Of the total number of patients, 43.5% died. The median overall survival of patients after LVAD implantation was 22 months. In the entire study population, survival rates were 88.04% at one month, 80.43% at six months, 70.65% at one year, and 61.96% at two years. Preoperative RHF was present in 24 patients, 12 of whom died and 12 survived LVAD implantation. Only two survivors developed early RHF (ERHF) and two late RHF (LRHF). The most significant predictors of ERHF development are brain natriuretic peptide (BNP), pre-surgery RHF, FAC < 20%, prior renal insufficiency, and total duration of ICU stay (HR: 1.002, 0.901, 0.858, 23.554, and 1.005, respectively). RHF following LVAD implantation is an unwanted complication with a negative impact on treatment outcome. The increased risk of fatal outcome in patients with ERHF and LRHF after LVAD implantation results in a need to identify patients at risk of RHF, in order to administer the available preventive and therapeutic methods.

Impact of tricuspid regurgitation on late right ventricular failure in left ventricular assist device patients ~can prophylactic tricuspid annuloplasty prevent late right ventricular failure? ~

BACKGROUND

In this study, we evaluated the prevalence of tricuspid regurgitation (TR) worsening in patients with left ventricular assist devices (LVADs) and its impact on late right ventricular (RV) failure.

METHODS

We enrolled 147 patients of the 184 patients who underwent continuous-flow LVAD implantations from 2005 to March 2018. The prevalence of postoperative TR worsening and late RV failure were retrospectively evaluated.

RESULTS

Concomitant tricuspid annuloplasty (TAP) was performed in 28 of 41 patients (68%) with preoperative TR greater than or equal to moderate (TR group) and in 23 of 106 patients (22%) with preoperative TR less than or equal to mild (non-TR group). Regarding the TR-free rates, despite receiving or not receiving concomitant TAP, there was no significant difference between the 2 groups (TR group: p = 0.37; non-TR group: p = 0.42). Of the 9 patients with postoperative TR greater than or equal to moderate, late RV failure developed in 3 patients, with TR worsening after RV failure in each case. During follow-up, 16 patients (11%) had late RV failure. As for the late RV failure-free rates, despite receiving or not receiving concomitant TAP, there was no significant difference between the 2 groups (TR group: p = 0.37; non-TR group: p = 0.96).

CONCLUSIONS

TR prognosis was preferable regardless of a patient receiving concomitant TAP; however, the presence of postoperative TR seemed to unrelated to late RV failure. Prophylactic TAP might not be necessary to prevent late RV failure.

Contemporary outcomes of continuous-flow left ventricular assist devices-a systematic review

Background

End stage heart failure is a major cause of morbidity and mortality, and its prevalence is expected to rise with the ageing population. For suitable patients, orthotopic heart transplantation remains the gold standard therapy, however, a paucity of donor organs has led to the development of left ventricular assist devices (LVAD). These devices can be utilized as either a bridge-to-transplant (BTT) or as an alternative to heart transplantation. While these devices can prolong life and improve quality of life, they are associated with a significant number of adverse events. We aim to systematically review the literature to quantify survival and the incidence of adverse events following implantation of continuous-flow LVADs (cf-LVAD).

Methods

A systematic review was performed to determine outcomes following implantation of a cf-LVAD. Primary outcomes were survival and frequency of adverse events (such as bleeding, infection, thrombosis, stroke and right ventricular failure). Secondary outcomes included quality of life and assessment of functional status.

Results

Sixty-three studies reported clinical outcomes of 9,280 patients. Survival after cf-LVAD varied between studies. Industry-funded trials generally reported better overall survival than the single- and multi-center case series, which showed significant variation. The largest registry report documented twelve, twenty-four and forty-eight-month survival rates of 82%, 72% and 57% respectively. The most commonly reported adverse events were gastrointestinal bleeding (GIB), device-related infection, neurological events and right heart failure (RHF). Bleeding, RHF and infection were the most frequent complications experienced by those supported with cf-LVAD, occurring in up to 35%, 40% and 55% of patients, respectively. Quality of life as measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and functional status as measured with the 6-minute walk test (6MWT) improved after cf-LVAD implantation with no decline evident two years after implantation.

Conclusions

The paucity of donor hearts has led to the development of left-ventricular assist devices as a BTT or as a destination therapy (DT). Outcomes after cf-LVAD implantation are excellent, with short-term survival comparable to heart transplantation, but long-term survival remains limited due to the incidence of post-implantation adverse events. Despite these complications, quality of life and functional status improve significantly post-implantation and remain improved over the long-term. This study demonstrates the potential benefits of cf-LVAD therapy whilst also identifying adverse events as an area of increased morbidity and mortality.

Left Ventricular Assist Device as Destination Therapy: a State of the Science and Art of Long-Term Mechanical Circulatory Support

PURPOSE OF REVIEW

The purpose of this review is to synthesize and summarize recent developments in the care of patients with end-stage heart failure being managed with a left ventricular assist device (LVAD) as destination therapy.

RECENT FINDINGS

Although the survival of patients treated with LVAD continues to improve, the rates of LVAD-associated complication, such as right ventricular failure, bleeding complications, and major infection, remain high, and management of these patients remains challenging. The durability and hemocompatibility of LVAD support have greatly increased in recent years as a result of new technologies and novel management strategies. Challenges remain in the comprehensive care of patients with destination therapy LVADs, including management of comorbidities and optimizing patient function and quality of life.

Preload Sensitivity with TORVAD Counterpulse Support Prevents Suction and Overpumping

PURPOSE

This study compares preload sensitivity of continuous flow (CF) VAD support to counterpulsation using the Windmill toroidal VAD (TORVAD). The TORVAD is a two-piston rotary pump that ejects 30 mL in early diastole, which increases cardiac output while preserving aortic valve flow.

METHODS

Preload sensitivity was compared for CF vs. TORVAD counterpulse support using two lumped parameter models of the cardiovascular system: (1) an open-loop model of the systemic circulation was used to obtain ventricular function curves by isolating the systemic circulation and prescribing preload and afterload boundary conditions, and (2) a closed-loop model was used to test the physiological response to changes in pulmonary vascular resistance, systemic vascular resistance, heart rate, inotropic state, and blood volume. In the open-loop model, ventricular function curves (cardiac output vs left ventricular preload) are used to assess preload sensitivity. In the closed-loop model, left ventricular end systolic volume is used to assess the risk of left ventricular suction.

RESULTS

At low preloads of 5 mmHg, CF support overpumps the circulation compared to TORVAD counterpulse support (cardiac output of 3.3 L/min for the healthy heart, 4.7 with CF support, and 3.5 with TORVAD counterpulse support) and has much less sensitivity than counterpulse support (0.342 L/min/mmHg for the healthy heart, 0.092 with CF support, and 0.306 with TORVAD counterpulse support). In the closed-loop model, when PVR is increased beyond 0.035 mmHg s/mL, CF support overpumps the circulation and causes ventricular suction events, but TORVAD counterpulse support maintains sufficient ventricular volume and does not cause suction.

CONCLUSIONS

Counterpulse support with the TORVAD preserves aortic valve flow and provides physiological sensitivity across all preload conditions. This should prevent overpumping and minimize the risk of suction.

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.

Role of imaging in diagnosis and management of left ventricular assist device complications

Heart failure is a clinical condition that is associated with significant morbidity and mortality. With the advent of left ventricular assist device (LVAD), an increasing number of patients have received an artificial heart both as a bridge-to-therapy and as a destination therapy. Clinical trials have shown clear survival benefits of LVAD implantation. However, the increased survival benefits and improved quality of life come at the expense of an increased complication rate. Common complications include perioperative bleeding, infection, device thrombosis, gastrointestinal bleeding, right heart failure, and aortic hemodynamic changes. The LVAD-associated complications have unique pathophysiology. Multiple imaging modalities can be employed to investigate the complications, including computed tomography (CT), positron emission tomography-computed tomography (PET-CT), catheter angiography and echocardiography. Imaging studies not only help ascertain diagnosis and evaluate the severity of disease, but also help direct relevant clinical management and predict prognosis. In this article, we aim to review the common LVAD complications, present the associated imaging features and discuss the role of imaging in their management.

Choosing Between Left Ventricular Assist Devices and Biventricular Assist Devices

Right ventricular failure following left ventricular assist devices implantation is a serious complication associated with high mortality. In patients with or at high risk of developing right ventricular failure, biventricular support is recommended. Because univentricular support is associated with high survival rates, biventricular support is often undertaken as a last resort. With the advent of newer right ventricular and biventricular systems under design and testing, better differentiation is required to ensure optimal patients care. Clear guidelines on patient selection, time of intervention and device selection are required to improve patient outcomes.

Novel Insights and Treatment Strategies for Right Heart Failure

PURPOSE OF REVIEW

The function of the right ventricle (RV) is intimately linked to its preload (systemic volume status) and afterload (pulmonary vasculature). In this review, we explore current knowledge in RV physiology, RV function assessment, causes of right heart failure (RHF), and specific treatment strategies for RHF.

RECENT FINDINGS

We examine the evidence behind new pharmacological therapies available, such as macitentan and riociguat in the treatment of specific etiologies of RHF. We will also focus on RHF in the setting of heart failure with preserved ejection fraction (HFpEF) and in the presence of left ventricular assist devices (LVAD), looking at current treatment recommendations, including mechanical circulatory support. Lastly, we will look to the horizon for the latest research on RHF, including the molecular basis of RHF and potential novel treatment methods for this old yet poorly understood syndrome. Disturbances in this complex relationship result in the clinical syndrome of RHF. Despite advances in the management of left heart diseases, much work remains to be done to understand and manage RHF.

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.

Investigating the Role of Interventricular Interdependence in Development of Right Heart Dysfunction During LVAD Support: A Patient-Specific Methods-Based Approach

Predictive computation models offer the potential to uncover the mechanisms of treatments whose actions cannot be easily determined by experimental or imaging techniques. This is particularly relevant for investigating left ventricular mechanical assistance, a therapy for end-stage heart failure, which is increasingly used as more than just a bridge-to-transplant therapy. The high incidence of right ventricular failure following left ventricular assistance reflects an undesired consequence of treatment, which has been hypothesized to be related to the mechanical interdependence between the two ventricles. To investigate the implication of this interdependence specifically in the setting of left ventricular assistance device (LVAD) support, we introduce a patient-specific finite-element model of dilated chronic heart failure. The model geometry and material parameters were calibrated using patient-specific clinical data, producing a mechanical surrogate of the failing in vivo heart that models its dynamic strain and stress throughout the cardiac cycle. The model of the heart was coupled to lumped-parameter circulatory systems to simulate realistic ventricular loading conditions. Finally, the impact of ventricular assistance was investigated by incorporating a pump with pressure-flow characteristics of an LVAD (HeartMate II™ operating between 8 and 12 k RPM) in parallel to the left ventricle. This allowed us to investigate the mechanical impact of acute left ventricular assistance at multiple operating-speeds on right ventricular mechanics and septal wall motion. Our findings show that left ventricular assistance reduces myofiber stress in the left ventricle and, to a lesser extent, right ventricle free wall, while increasing leftward septal-shift with increased operating-speeds. These effects were achieved with secondary, potentially negative effects on the interventricular septum which showed that support from LVADs, introduces unnatural bending of the septum and with it, increased localized stress regions. Left ventricular assistance unloads the left ventricle significantly and shifts the right ventricular pressure-volume-loop toward larger volumes and higher pressures; a consequence of left-to-right ventricular interactions and a leftward septal shift. The methods and results described in the present study are a meaningful advancement of computational efforts to investigate heart-failure therapies in silico and illustrate the potential of computational models to aid understanding of complex mechanical and hemodynamic effects of new therapies.

Treatment and Prognosis of Pulmonary Hypertension in the Left Ventricular Assist Device Patient

This review will discuss the medical management of pulmonary hypertension in patients with left ventricular assist devices. Although much has been written on the management of primary pulmonary hypertension, also called pulmonary arterial hypertension, this review will instead focus on the treatment of pulmonary hypertension secondary to left heart disease. The relevant pharmacotherapy can be divided into medications for treating heart failure, such as diuretics and β-blockers, and medications for treating pulmonary hypertension. We also discuss important preoperative considerations in patients with pulmonary hypertension; the relationships between left ventricular assist devices, pulmonary hemodynamics, and right heart failure; as well as optimal perioperative and long-term postoperative medical management of pulmonary hypertension.

Partial LVAD restores ventricular outputs and normalizes LV but not RV stress distributions in the acutely failing heart in silico

PURPOSE

Heart failure is a worldwide epidemic that is unlikely to change as the population ages and life expectancy increases. We sought to detail significant recent improvements to the Dassault Systèmes Living Heart Model (LHM) and use the LHM to compute left ventricular (LV) and right ventricular (RV) myofiber stress distributions under the following 4 conditions: (1) normal cardiac function; (2) acute left heart failure (ALHF); (3) ALHF treated using an LV assist device (LVAD) flow rate of 2 L/min; and (4) ALHF treated using an LVAD flow rate of 4.5 L/min.

METHODS AND RESULTS

Incorporating improved systolic myocardial material properties in the LHM resulted in its ability to simulate the Frank-Starling law of the heart. We decreased myocardial contractility in the LV myocardium so that LV ejection fraction decreased from 56% to 28%. This caused mean LV end diastolic (ED) stress to increase to 508% of normal, mean LV end systolic (ES) stress to increase to 113% of normal, mean RV ED stress to decrease to 94% of normal and RV ES to increase to 570% of normal. When ALHF in the model was treated with an LVAD flow rate of 4.5 L/min, most stress results normalized. Mean LV ED stress became 85% of normal, mean LV ES stress became 109% of normal and mean RV ED stress became 95% of normal. However, mean RV ES stress improved less dramatically (to 342% of normal values).

CONCLUSIONS

These simulations strongly suggest that an LVAD is effective in normalizing LV stresses but not RV stresses that become elevated as a result of ALHF.

Inhaled therapy for the management of perioperative pulmonary hypertension

Patients with pulmonary hypertension (PH) are at high risk for complications in the perioperative setting and often receive vasodilators to control elevated pulmonary artery pressure (PAP). Administration of vasodilators via inhalation is an effective strategy for reducing PAP while avoiding systemic side effects, chiefly hypotension. The prototypical inhaled pulmonary-specific vasodilator, nitric oxide (NO), has a proven track record but is expensive and cumbersome to implement. Alternatives to NO, including prostanoids (such as epoprostenol, iloprost, and treprostinil), NO-donating drugs (sodium nitroprusside, nitroglycerin, and nitrite), and phosphodiesterase inhibitors (milrinone, sildenafil) may be given via inhalation for the purpose of treating elevated PAP. This review will focus on the perioperative therapy of PH using inhaled vasodilators.

The Right Ventricular Function After Left Ventricular Assist Device (RVF-LVAD) study: rationale and preliminary results

AIMS

Despite improved outcomes and lower right ventricular failure (RVF) rates with continuous-flow left ventricular assist devices (LVADs), RVF still occurs in 20-40% of LVAD recipients and leads to worse clinical and patient-centred outcomes and higher utilization of healthcare resources. Preoperative quantification of RV function with echocardiography has only recently been considered for RVF prediction, and RV mechanics have not been prospectively evaluated.

METHODS AND RESULTS

In this single-centre prospective cohort study, we plan to enroll a total of 120 LVAD candidates to evaluate standard and mechanics-based echocardiographic measures of RV function, obtained within 7 days of planned LVAD surgery, for prediction of (i) RVF within 90 days; (ii) quality of life (QoL) at 90 days; and (iii) RV function recovery at 90 days post-LVAD. Our primary hypothesis is that an RV echocardiographic score will predict RVF with clinically relevant discrimination (C >0.85) and positive and negative predictive values (>80%). Our secondary hypothesis is that the RV score will predict QoL and RV recovery by 90 days. We expect that RV mechanics will provide incremental prognostic information for these outcomes. The preliminary results of an interim analysis are encouraging.

CONCLUSION

The results of this study may help improve LVAD outcomes and reduce resource utilization by facilitating shared decision-making and selection for LVAD implantation, provide insights into RV function recovery, and potentially inform reassessment of LVAD timing in patients at high risk for RVF.

Four-year outcomes with third-generation centrifugal left ventricular assist devices in an era of restricted transplantation

OBJECTIVES

Third-generation ventricular assist devices (VADs) are associated with improved outcomes, though in recent clinical trials bridge-to-transplant (BTT) rates are ∼30% at 6 months, so that transplantation can be used as a ‘bail out’ for serious complications. In the UK, there was a significant reduction in heart transplantation rates over the last decade, so that transplantation from VADs is much less frequent. The objective of this study was to determine outcomes and their predictors in this situation of low BTT rates, and as patients were exposed to long-term support, the incidence and outcomes of VAD thrombosis.

METHODS

We analysed outcomes for 102 consecutive patients between 2009 and 2013 (mean age 47 ± 13; VentrAssist n = 6 and HeartWare n = 96). The median duration of support was 462 ± 426 days.

RESULTS

Survival rates on the device were 75 and 66% at 1 and 2 years, respectively. Older age and more acute INTERMACS groups were significantly related to reduced survival within the first 90 days (P = 0.030 and 0.010, respectively). Poor preoperative right ventricular (RV) function had a negative effect on survival after 1 year (P = 0.009), though not earlier. VAD thrombosis (n = 24 HeartWare and n = 1 VentrAssist) occurred at 0.18 events per patient-year for HeartWare and 0.07 for VentrAssist devices at a median time of onset at 404 ± 281 days. There was no significant effect of VAD thrombosis on survival. Only 14 of 102 patients were transplanted at a median of 334 ± 347 days, and only 3 were transplanted within the first 6 months.

CONCLUSIONS

Third-generation left ventricular assist device implants with a low rate of transplantation have similar survival to destination therapy, and are susceptible to long-term complications of VAD thrombosis and right heart failure.

Critical Care Transthoracic Echocardiography: Atrial Sinus Rhythm During Ventricular Fibrillation

A 70-year-old man with end-stage heart failure and a continuous-flow left ventricular assist device received repeated electrical discharges from his biventricular implantable cardiac defibrillator. Although the electrocardiogram demonstrated ventricular fibrillation, the patient was awake and in no distress. A focused transthoracic echocardiogram was performed to assess ventricular function revealing simultaneous atrial sinus rhythm and ventricular fibrillation. This clinical scenario highlights a unique clinical finding, the complexity of the care of continuous-flow left ventricular assist device patients, and the challenges of intensivist-performed bedside focused transthoracic echocardiogram.

Mechanical circulatory support: devices, outcomes and complications

Systolic heart failure is a problem of substantial magnitude worldwide. Over the last 25 years great progress has been made in the medical management of heart failure with the recognition of the benefits of beta-adrenergic blockade, modulation of the renin-angiotensin and mineralocorticoid axes and judicious diuretic therapy. In addition, cardiac resynchronization therapy and prophylactic implantation of cardiac defibrillators have been responsible for measurable benefits in terms of functional status and dysrhythmia-related mortality, respectively. Unfortunately, progressive cardiac dysfunction often results in activity limitation, symptoms at rest, hospital admission, end-organ dysfunction and death despite maximal implementation of standard therapies. Heart transplantation has been a dramatic and effective therapy for end-stage heart failure, but it remains limited by a shortage of donor organs, strict criteria defining acceptable recipients and often unsatisfactory long-term success. Mechanical alternatives to support the failing circulation have been sought for the last 50 years. The history of device development has been marked in general by the slow progress achieved by a few dedicated and persevering pioneers. In the past decade, however, evolving technology has dramatically changed the field and broadened the options for the treatment of advanced heart failure. This review will detail the important milestones and the current state of the art, with an emphasis on implantable devices for intermediate to long term support.

Current status of mechanical circulatory support: a systematic review

Heart failure is a major public health problem and its management requires a significant amount of health care resources. Even with administration of the best available medical treatment, the mortality associated with the disease remains high. As therapeutical strategies for heart failure have been refined, the number of patients suffering from the disease has expanded dramatically. Although heart transplantation still represents the gold standard therapeutical approach, the implantation of mechanical circulatory support devices (MCSDs) evolved to a well-established management for this disease. The limited applicability of heart transplantation caused by a shortage of donor organs and the concurrent expand of the patient population with end-stage heart failure led to a considerable utilization of MCSDs. This paper outlines the current status of mechanical circulatory support.