Right heart failure post left ventricular assist device implantation

Contemporary treatment of right ventricular failure

Right ventricular failure (RVF) is a clinical syndrome resulting from structural and functional changes in the right ventricle (RV), leading to inadequate blood flow to the pulmonary circulation and elevated systemic venous pressures. Factors modulating RV function include afterload, preload, contractility, and interventricular dependency. The pathophysiology of RVF involves complex interactions, such as maladaptive hypertrophy, metabolic reprogramming, inflammation, fibrosis, apoptosis, and endothelial dysfunction. Therapeutic strategies are limited for RVF, as basic and clinical research has historically focused mainly on the left ventricle. Novel pharmacological interventions targeting metabolism, calcium homeostasis, oxidative stress, extracellular matrix remodeling, endothelial function, and inflammation are needed to address RVF effectively. This review explores the etiology, mechanisms, and pathophysiology of RVF, drugs directly targeting the RV myocardium, the intricate biological processes between RV and pulmonary vascular remodeling, surgical and device therapies, and future perspectives on managing RVF.

Retrospective Evaluation of Inpatient Warfarin Management Practices in Patients Immediately Following Left Ventricular Assist Device Implantation

Background: The International Society for Heart and Lung Transplantation recommends patients receive warfarin and aspirin following left ventricular assist device (LVAD) placement. Optimal warfarin management in this population has not been well established. Objectives: The objectives of this study were to evaluate warfarin practices in patients immediately post-LVAD implantation. Methods: This single-center, retrospective cohort study included patients 18 years and older following LVAD placement from August 1, 2012 to April 1, 2020. The primary outcome was to assess patient-specific risk factors affecting time to therapeutic range. Secondary outcomes included bleeding events, thrombotic events, and warfarin dosing patterns. Results: Of 104 included patients, 91% reached the therapeutic range at a median of 8 days. A higher proportion of patients started on 3.5 mg or higher reached therapeutic international normalized ratio (INR) and faster (96% vs 90%; 8 vs 5 days) compared to lower doses. Univariate analysis of associations with reaching therapeutic INR range included initial warfarin dose, cumulative warfarin, and warfarin dosing changes, whereas HAS-BLED and CHA2DS2VAC were associated with slower time to therapeutic INR. Overall, 44% of patients met Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) bleeding criteria. There were a total of 12 thrombotic events and no pump thrombotic events. Total weekly warfarin dosing was significantly lower post-LVAD (24.3 mg vs 35 mg, P = 0.0009). In addition, warfarin requirements were statistically higher after the first week of therapy (4.0 mg vs 2.89 mg, P < 0.0001). Conclusion: Based on the results, consider warfarin starting dose between 2.5 and 4 mg for patients on LVAD therapy, while balancing patient-specific risks for bleeding.

Outcomes of left ventricular assist device implantations at Karolinska University Hospital: A retrospective study

Background

To descriptively present data and outcomes of left ventricular assist device (LVAD) implantations at Karolinska University Hospital.

Methods

Data were collected from consecutive patients (n = 44) who were implanted with HeartMate 3 (HM3) at Karolinska University Hospital between 2017 and 2022. The study presents baseline characteristics, clinical course during the inpatient hospital care after implantation, adverse events, and clinical outcomes.

Results

Median intensive care unit stay and hospital stay after HM3 implantation was 8 (interquartile range [IQR] 6; 15) and 28 days (IQR 22; 36), respectively. In total, 73% underwent ramp test at some point after the implantation. Death from all causes within 30 days postimplantation was 5%. A total of 21 patients (48%) underwent right heart catheterization, at a median of 0.5 years (IQR 0.3; 0.7) after implantation, and all exhibited optimally unloaded left ventricles. During the study period, 34% of the patients were transplanted, 5% were explanted, and 16% died with LVAD. In total, 11% and 5% suffered from early and late right ventricle failures, respectively. Acute renal failure affected 46% and 18% had driveline infection. Spontaneous cerebral hemorrhage and cerebral infarction affected 5% and 7% of the study population, respectively. Gastrointestinal bleeding affected 16%. The median LVAD duration was 10 months (IQR 5; 22). The 1-year survival rate with LVAD was 85%, and the 2-year survival rate was 80%.

Conclusions

The results of this low-volume single-center retrospective study on LVAD implantations align with the results of other studies and international registries.

Epidemiology of perioperative RV dysfunction: risk factors, incidence, and clinical implications

In this edition of the journal, the Perioperative Quality Initiative (POQI) present three manuscripts describing the physiology, assessment, and management of right ventricular dysfunction (RVD) as pertains to the perioperative setting. This narrative review seeks to provide context for these manuscripts, discussing the epidemiology of perioperative RVD focussing on definition, risk factors, and clinical implications. Throughout the perioperative period, there are many potential risk factors/insults predisposing to perioperative RVD including pre-existing RVD, fluid overload, myocardial ischaemia, pulmonary embolism, lung injury, mechanical ventilation, hypoxia and hypercarbia, lung resection, medullary reaming and cement implantation, cardiac surgery, cardiopulmonary bypass, heart and lung transplantation, and left ventricular assist device implantation. There has however been little systematic attempt to quantify the incidence of perioperative RVD. What limited data exists has assessed perioperative RVD using echocardiography, cardiovascular magnetic resonance, and pulmonary artery catheterisation but is beset by challenges resulting from the inconsistencies in RVD definitions. Alongside differences in patient and surgical risk profile, this leads to wide variation in the incidence estimate. Data concerning the clinical implications of perioperative RVD is even more scarce, though there is evidence to suggest RVD is associated with atrial arrhythmias and prolonged length of critical care stay following thoracic surgery, increased need for inotropic support in revision orthopaedic surgery, and increased critical care requirement and mortality following cardiac surgery. Acute manifestations of RVD result from low cardiac output or systemic venous congestion, which are non-specific to the diagnosis of RVD. As such, RVD is easily overlooked, and the relative contribution of RV dysfunction to postoperative morbidity is likely to be underestimated.We applaud the POQI group for highlighting this important condition. There is undoubtedly a need for further study of the RV in the perioperative period in addition to solutions for perioperative risk prediction and management strategies. There is much to understand, study, and trial in this area, but importantly for our patients, we are increasingly recognising the importance of these uncertainties.

Pressure-Volume Loops for Reviewing Right Ventricular Physiology and Failure in the Context of Left Ventricular Assist Device Implantation

Right ventricular (RV) function is complex as a number of determinants beyond preload, inotropy and afterload play a fundamental role. In particular, arterial elastance (Ea), ventriculo-arterial coupling (VAC), and (systolic) ventricular interdependence play a vital role for the right ventricle. Understanding and actively visualizing these interactions in the failing RV as well as in the altered hemodynamic and morphological situation of left ventricular assist device (LVAD) implantation may aid clinicians in their understanding of RV dysfunction and failure. While, admittedly, hard data is scarce and invasive pressure-volume loop measurements will not become routine in cardiac surgery, we hope that clinicians will benefit from the comprehensive, simulation-based review of RV pathology. In particular, the aim of this article is to first, address and clarify the pathophysiologic hemodynamic factors that lead to RV dysfunction and then, second, expand upon this basis examining the changes occurring by LVAD implantation. This is illustrated using Harvi software which shows elastance, ventricular arterial coupling, and ventricular interdependence by simultaneously showing pressure volume loops of the right and left ventricle.

Care and Monitoring of Pregnant Patients With Left Ventricular Assist Devices

Cardiovascular disease is one of the leading causes of maternal mortality in the United States. Although still rare, pregnancy in patients with left ventricular assist devices (LVADs) is becoming more common. Typical indications for the use of LVADs in reproductive-aged females include ischemic cardiomyopathy, nonischemic (familial) dilated cardiomyopathy, peripartum cardiomyopathy, and some forms of myocarditis. An LVAD drains blood through a cannula placed into the apex of the left ventricle and then returns it to the proximal aorta bypassing the aortic valve allowing hemodynamic support in parallel with the native circulation. The physiologic changes associated with pregnancy, mainly increased blood volume and hypercoagulability, may adversely affect patients with LVADs, leading to many experts recommending against pregnancy. Maternal-fetal medicine specialists should have a central role within a multidisciplinary team required to provide optimal care for this high-risk group of patients.

Impact of Pre-Operative Right Ventricular Response to Hemodynamic Optimization on Outcomes in Patients with LVADs

Background: Right ventricular failure (RVF) continues to affect patients supported with durable left ventricular assist devices (LVAD) and results in increased morbidity and mortality. Information regarding the impact of right ventricular response to pre-operative optimization on outcomes is scarce. Methods: Single-center retrospective analysis of consecutive patients who underwent first continuous flow LVAD implantation between 2006 and 2020. Patients with bi-ventricular support before LVAD or without hemodynamic data were excluded. Invasive hemodynamics at baseline and after pre-operative medical and/or temporary circulatory support were recorded. Patients were grouped in the following categories: A: No Hemodynamic RV dysfunction (RVD) at baseline; B: RVD with achievement of RV hemodynamic optimization goals; C: RVD without achievement of RV optimization goals. The main outcomes were right ventricular failure defined as inotropes >14 days after implantation, or postoperative right ventricular mechanical support, and all-cause mortality. Results: Overall, 128 patients were included in the study. The mean age was 58 ±12.5 years, 74.2% were males and, 68.7% had non-ischemic cardiomyopathy. Hemodynamic RVD was present in 70 (54.7%) of the patients at baseline. RV hemodynamic goals were achieved in 46 (79.31%) patients with RVD and in all the patients without RVD at baseline. Failure to achieve hemodynamic optimization goals was associated with a significantly higher risk of RVF after LVAD implantation (adjusted OR 4.37, 95% CI 1.14−16.76, p = 0.031) compared with no RVD at baseline and increased 1-year mortality compared with no RVD (adjusted HR 4.1, 95% CI 1.24−13.2, p = 0.02) and optimized RVD (adjusted HR 6.4, 95% CI 1.6−25.2, p = 0.008).Conclusion: Among patients with RVD, the inability to achieve hemodynamic optimization goals was associated with higher rates of RV failure and increased 1-year all-cause mortality post LVAD implantation.

The “Right” Definition for Post–Left Ventricular Assist Device Right Heart Failure: The More We Learn, the Less We Know

Right heart failure is a major cause of morbidity and mortality following left ventricular assist device implantation. Over the past few decades, the definition proposed by the Interagency Registry of Mechanical Circulatory Support and Society of Thoracic Surgeons has continually evolved to better identify this complex pathology. We propose that the latest definition proposed by the Mechanical Circulatory Support Academic Research Consortium in 2020 will increase our recognition and understanding of this complex disease phenomenon.

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.

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.

Perioperative right ventricular function and dysfunction in adult cardiac surgery-focused review (part 2-management of right ventricular failure)

The single most important factor in improving outcomes in right ventricular (RV) failure is anticipating and recognizing it. Once established, a vicious circle of systemic hypotension, and RV ischemia and dilation, occurs, leading to cardiogenic shock, multi-organ failure, and death. RV dysfunction and failure theoretically can occur in three settings-increase in the pre-load; increase in after load; and decrease in contractility. For patients deemed low risk for the development of RV failure, when it occurs, the correction of underlying cause is the most important and effective treatment strategy. Therapy of RV failure must focus on improving the RV coronary perfusion, lowering pulmonary vascular resistance, and optimizing the pre-load. Pre-load and after-load optimization, ventilator adjustments, and improving the contractility of RV by inotropes are the first line of therapy and should be initiated early to prevent multi-organ damage. Mechanical assist device implantation or circulatory support with extracorporeal membrane oxygenation (ECMO) may be needed in refractory cases.

Surgical Management of Heart Failure

Optimal management of heart failure is collaborative, with the involvement of specialist heart failure physicians, nurses, interventionalists, and surgeons. In addition to medical optimisation and cardiac resynchronisation therapy, surgery plays a valuable role in many patients. We herein study the evidence and the role of surgical intervention in functional mitral regurgitation, coronary revascularisation in ischaemic cardiomyopathy, and surgical ventricular reconstruction. Additionally, we describe techniques of temporary and durable mechanical circulatory support, with their relative advantages and disadvantages, and applications. Finally, we describe the history and nomenclature around heart transplants, their indications, techniques, present-day outcomes, complications, and new developments in the field.

The Human Explanted Heart Program: A translational bridge for cardiovascular medicine

The progression of cardiovascular research is often impeded by the lack of reliable disease models that fully recapitulate the pathogenesis in humans. These limitations apply to both in vitro models such as cell-based cultures and in vivo animal models which invariably are limited to simulate the complexity of cardiovascular disease in humans. Implementing human heart tissue in cardiovascular research complements our research strategy using preclinical models. We established the Human Explanted Heart Program (HELP) which integrates clinical, tissue and molecular phenotyping thereby providing a comprehensive evaluation into human heart disease. Our collection and storage of biospecimens allow them to retain key pathogenic findings while providing novel insights into human heart failure. The use of human non-failing control explanted hearts provides a valuable comparison group for the diseased explanted hearts. Using HELP we have been able to create a tissue repository which have been used for genetic, molecular, cellular, and histological studies. This review describes the process of collection and use of explanted human heart specimens encompassing a spectrum of pediatric and adult heart diseases, while highlighting the role of these invaluable specimens in translational research. Furthermore, we highlight the efficient procurement and bio-preservation approaches ensuring analytical quality of heart specimens acquired in the context of heart donation and transplantation.

Right Ventricular Strain to Assess Early Right Heart Failure in the Left Ventricular Assist Device Candidate

PURPOSE OF REVIEW

Right heart failure (RHF) following left ventricular assist device implantation (LVAD) remains the primary cause of postoperative mortality and morbidity, and prediction of RHF is the main interest of the transplantation community. In this review, we outline the role and impact of right ventricular strain in the evaluation of the right ventricle function before LVAD implantation.

RECENT FINDINGS

Accumulating data suggest that measurement of right ventricular longitudinal strain (RVLS) has a critical role in predicting RHF preoperatively and may improve morbidity and mortality following LVAD implantation. However, the significant intraobserver, interobserver variability, the lack of multicenter, prospective studies, and the need for a learning curve remain the most critical limitations in the clinical practice at present. This review highlighted the importance of right ventricular strain in the diagnosis of RHF preoperatively and revealed that RVLS might have a crucial clinical measurement for the selection and management of LVAD patients in the future with the more extensive multicenter studies.

Association of preoperative duration of inotropy on prevalence of right ventricular failure following LVAD implantation

Aims

20% to 40% of left ventricular assist device (LVAD) device implantations are complicated by right ventricular (RV) failure that results in significant morbidity and mortality. We hypothesized that the duration on milrinone infusion is an independent risk factor for RV failure following LVAD implantation.

Methods and results

Retrospective demographic, clinical and hemodynamic data were collected on all adults with ACC/AHA stage D heart failure on intravenous milrinone who underwent LVAD implantation between 2012 and 2019. Patients (n = 104) were divided into two groups, those on milrinone <30 days (STM, n = 55) vs. ≥30 (LTM, n = 49). The primary endpoint was the prevalence of RV failure (need for inotropic support for more than 14 days or RV assist device) within 30 days post‐LVAD implantation. There were no significant differences between STM and LTM patients with respect to demographic, echocardiographic, right heart catheterization data, or baseline medications. The mean age of patients was 55.6 ± 12 years (70% male patients). Mean duration on milrinone was 13.7 vs. 81.0 days in STM and LTM, respectively. Forty‐five (43.3%) patients developed RV failure. LTM had higher prevalence of RV failure with odds ratio (OR) = 5.04 (95% CI 2.18–11.68, P = 0.0002). After adjusting for age, gender, and co‐morbidity count, the OR was 6.33 (95% CI 2.51–15.93), P < 0.0001.

Conclusions

In this retrospective study of ACC/AHA stage D HF patients, longer duration of milrinone infusion was associated with higher prevalence of RV failure after LVAD implantation.

Dynamic Augmentation of Left Ventricle and Mitral Valve Function With an Implantable Soft Robotic Device

Left ventricular failure is strongly associated with secondary mitral valve regurgitation. Implantable soft robotic devices are an emerging technology that enables augmentation of a native function of a target tissue. We demonstrate the ability of a novel soft robotic ventricular assist device to dynamically augment left ventricular contraction, provide native pulsatile flow, simultaneously reshape the mitral valve apparatus, and eliminate the associated regurgitation in an Short-term large animal model of acute left ventricular systolic dysfunction.

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.

Hurdles to Cardioprotection in the Critically Ill

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.

Two-dimensional Echocardiographic Assessment of Myocardial Strain: Important Echocardiographic Parameter Readily Useful in Clinical Field

Echocardiography is the first and is the most-available imaging modality for many cardiovascular diseases, and echocardiographic parameters can give much important information for diagnosis, treatment, and prognostic evaluations. Left ventricular ejection fraction (LVEF) is the most commonly used echocardiographic parameter for left ventricular (LV) systolic function. Although LVEF is used routinely in daily practice, it is calculated from volumetric change without representing true myocardial properties. Recently, strain echocardiography has been used to objectively measure myocardial deformation. Myocardial strain can give accurate information about intrinsic myocardial function, and it can be used to detect early-stage cardiovascular diseases, monitor myocardial changes with specific therapies, differentiate cardiomyopathies, and predict the prognosis of several cardiovascular diseases. Although strain echocardiography has been applied to measure the right ventricle and left atrium, in addition to analyzing the LV, many cardiologists who are not imaging specialists are unaware of its clinical use and importance. Therefore, this review describes the measurement and clinical utility of 2-dimensional strain analysis in various cardiovascular diseases.

Preimplant Phosphodiesterase-5 Inhibitor Use Is Associated With Higher Rates of Severe Early Right Heart Failure After Left Ventricular Assist Device Implantation

Background Early right heart failure (RHF) occurs commonly in left ventricular assist device (LVAD) recipients, and increased right ventricular (RV) afterload may contribute. Selective pulmonary vasodilators, like phosphodiesterase-5 inhibitors (PDE5i), are used off-label to reduce RV afterload before LVAD implantation, but the association between preoperative PDE5i use and early RHF after LVAD is unknown. Methods and Results We analyzed adult patients from the INTERMACS registry (Interagency Registry for Mechanically Assisted Circulatory Support) who received a continuous flow LVAD after 2012. Patients on PDE5i were propensity-matched 1:1 to controls. The primary outcome was the incidence of severe early RHF, defined as the composite of death from RHF within 30 days, need for RV assist device support within 30 days, or use of inotropes beyond 14 days. Of 11 544 continuous flow LVAD recipients, 1199 (10.4%) received preoperative PDE5i. Compared to controls, patients on PDE5i had higher pulmonary artery systolic pressure (53.4 mm Hg versus 49.5 mm Hg) and pulmonary vascular resistance (2.6 WU versus 2.3 WU; P<0.001 for both). Before propensity matching, the incidence of severe early RHF was higher among patients on PDE5i than in controls (29.4% versus 23.1%; unadjusted odds ratio (OR), 1.32; 95% CI, 1.17-1.50). This association persisted after propensity matching (PDE5i, 28.9% versus control 23.7%; OR, 1.31; 95% CI, 1.09-1.57), driven by a higher incidence of prolonged inotropic support. Similar results were observed across a wide range of subgroups stratified by markers of pulmonary vascular disease and RV dysfunction. Conclusions Patients treated with preoperative PDE5i had markers of increased RV afterload and HF severity compared to unmatched controls. Even after propensity matching, patients receiving preimplant PDE5i therapy had higher rates of post-LVAD RHF.

Right ventricular failure following left ventricular assist device implantation is associated with a preoperative pro-inflammatory response

Background

Systemic inflammation during implant of a durable left ventricular assist device (LVAD) may contribute to adverse outcomes. We investigated the association of the preoperative inflammatory markers with subsequent right ventricular failure (RVF).

Materials and methods

Prospective data was collected on 489 patients from 2003 through 2017 who underwent implantation of a durable LVAD. Uni- and multivariable correlation with leukocytosis was determined using linear and binary logistic regression. The population was also separated into low (< 10.5 K/ul, n = 362) and high (> 10.5 K/ul, n = 127) white blood cell count (WBC) groups. Mantel-Cox statistics was used to analyze survival data.

Results

Postop RVF was associated with a higher preop WBC (11.3 + 5.7 vs 8.7 + 3.1) and C-reactive protein (CRP, 5.6 + 4.4 vs 3.3 + 4.7) levels. Multivariable analysis identified an independent association between increased WBC preoperatively with increased lactate dehydrogenase (LDH, P < 0.001), heart rate (P < 0.001), CRP (P = 0.006), creatinine (P = 0.048), and INR (P = 0.049). The high WBC group was more likely to be on preoperative temporary circulatory support (17.3% vs 6.4%, P < 0.001) with a trend towards greater use of an intra-aortic balloon pump (55.9% vs 47.2%, P = 0.093). The high WBC group had poorer mid-term survival (P = 0.042).

Conclusions

Postop RVF is associated with a preoperative pro-inflammatory environment. This may be secondary to the increased systemic stress of decompensated heart failure. Systemic inflammation in the decompensated heart failure may contribute to RVF after LVAD implant.

Characterization of biventricular alterations in myocardial (reverse) remodelling in aortic banding-induced chronic pressure overload

Aortic Stenosis (AS) is the most frequent valvulopathy in the western world. Traditionally aortic valve replacement (AVR) has been recommended immediately after the onset of heart failure (HF) symptoms. However, recent evidence suggests that AVR outcome can be improved if performed earlier. After AVR, the process of left ventricle (LV) reverse remodelling (RR) is variable and frequently incomplete. In this study, we aimed at detecting mechanism underlying the process of LV RR regarding myocardial structural, functional and molecular changes before the onset of HF symptoms. Wistar-Han rats were subjected to 7-weeks of ascending aortic-banding followed by a 2-week period of debanding to resemble AS-induced LV remodelling and the early events of AVR-induced RR, respectively. This resulted in 3 groups: Sham (n = 10), Banding (Ba, n = 15) and Debanding (Deb, n = 10). Concentric hypertrophy and diastolic dysfunction (DD) were patent in the Ba group. Aortic-debanding induced RR, which promoted LV functional recovery, while cardiac structure did not normalise. Cardiac parameters of RV dysfunction, assessed by echocardiography and at the cardiomyocyte level prevailed altered after debanding. After debanding, these alterations were accompanied by persistent changes in pathways associated to myocardial hypertrophy, fibrosis and LV inflammation. Aortic banding induced pulmonary arterial wall thickness to increase and correlates negatively with effort intolerance and positively with E/e′ and left atrial area. We described dysregulated pathways in LV and RV remodelling and RR after AVR. Importantly we showed important RV-side effects of aortic constriction, highlighting the impact that LV-reverse remodelling has on both ventricles.

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.

Computational analysis of the hemodynamic characteristics under interaction influence of β-blocker and LVAD

Background

Hemodynamic characteristics of the interaction influence among support level and model of LVAD, and coupling β-blocker has not been reported.

Methods

In this study, the effect of support level and model of LVAD on cardiovascular hemodynamic characteristics is investigated. In addition, the effect of β-blocker on unloading with LVAD is analyzed to elucidate the mechanism of LVAD coupling β-blocker. A multi-scale model from cell level to system level is proposed. Moreover, LVAD coupling β-blocker has been researching to explain the hemodynamics of cardiovascular system.

Results

Myocardial force was decreased along with the increase of support level of LVAD, and co-pulse mode was the lowest among the three support modes. Additionally, the β-blocker combined with LVAD significantly reduced the left ventricular volume compared with LVAD support without β-blocker. However, the left ventricular pressure under both cases has no significant difference. External work of right ventricular was increased along with the growth of support level of only LVAD. The LVAD under co-pulse mode achieved the lowest right-ventricular EW among the three support modes.

Conclusions

Co-pulse mode with β-blocker could be an optimal strategy for promoting cardiac structure and function recovery.

Engineering a Brighter Future: The Evolving Role of the Pharmacist in the Era of the HeartMate 3

Continuous-flow left-ventricular assist devices (CF-LVADs) are an option for patients with end-stage heart failure requiring durable mechanical circulatory support. Two of the older-generation CF-LVADs have been associated with multiple device-related complications, including bleeding and thrombosis. The newest generation CF-LVAD, the HeartMate 3, was engineered specifically to prevent device-related thrombosis. As more data enhance our understanding of the burden of bleeding and thrombotic adverse events, patients with durable mechanical circulatory support may require less-aggressive antithrombotic therapy.

Strain Analysis of the Right Ventricle Using Two-dimensional Echocardiography

Right ventricular (RV) systolic dysfunction has been identified as an independent prognostic marker of many cardiovascular diseases. However, there are problems in measuring RV systolic function objectively and identification of RV dysfunction using conventional echocardiography. Strain echocardiography is a new imaging modality to measure myocardial deformation. It can measure intrinsic myocardial function and has been used to measure regional and global left ventricular (LV) function. Although the RV has different morphologic characteristics than the LV, strain analysis of the RV is feasible. After strain echocardiography was introduced to measure RV systolic function, it became more popular and was incorporated into recent echocardiographic guidelines. Recent studies showed that RV global longitudinal strain (RVGLS) can be used as an objective index of RV systolic function with prognostic significance. In this review, we discuss RVGLS measurement, normal reference values, and the clinical importance of RVGLS.

The effect of heart failure and left ventricular assist device treatment on right ventricular mechanics: a computational study

Background and aims

Although it is important to analyze the hemodynamic factors related to the right ventricle (RV) after left ventricular assist device (LVAD) implantation, previous studies have focused only on the alteration of the ventricular shape and lack quantitative analysis of the various hemodynamic parameters. Therefore, we quantitatively analyzed various hemodynamic parameters related to the RV under normal, heart failure (HF), and HF incorporated with continuous flow LVAD therapy by using a computational model.

Methods

In this study, we combined a three-dimensional finite element electromechanical model of ventricles, which is based on human ventricular morphology captured by magnetic resonance imaging (MRI) with a lumped model of the circulatory system and continuous flow LVAD function in order to construct an integrated model of an LVAD implanted-cardiovascular system. To induce systolic dysfunction, the magnitude of the calcium transient function under HF condition was reduced to 70% of the normal value, and the time constant was reduced by 30% of the normal value.

Results

Under the HF condition, the left ventricular end systolic pressure decreased, the left ventricular end diastolic pressure increased, and the pressure in the right atrium (RA), RV, and pulmonary artery (PA) increased compared with the normal condition. The LVAD therapy decreased the end-systolic pressure of the LV by 41%, RA by 29%, RV by 53%, and PA by 71%, but increased the right ventricular ejection fraction by 52% and cardiac output by 40%, while the stroke work was reduced by 67% compared with the HF condition without LVAD. The end-systolic ventricular tension and strain decreased with the LVAD treatment.

Conclusion

LVAD enhances CO and mechanical unloading of the LV as well as those of the RV and prevents pulmonary hypertension which can be induced by HF.

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.

Modeling Right Ventricle Failure After Continuous Flow Left Ventricular Assist Device: A Biventricular Finite-Element and Lumped-Parameter Analysis

The risk of right ventricle (RV) failure remains a major contraindication for continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with heart failure. It is therefore critical to identify the patients who will benefit from early intervention to avoid adverse outcomes. We sought to advance the computational modeling description of the mechanisms underlying RV failure in LVAD-supported patients. RV failure was studied by computational modeling of hemodynamic and cardiac mechanics using lumped-parameter and biventricular finite element (FE) analysis. Findings were validated by comparison of bi-dimensional speckle-tracking echocardiographic strain assessment of the RV free wall vs. patient-specific computational strain estimations, and by non-invasive lumped-based hemodynamic predictions vs. invasive right heart catheterization data. Correlation analysis revealed that lumped-derived RV cardiac output (R = 0.94) and RV stroke work index (R = 0.85) were in good agreement with catheterization data collected from 7 patients with CF-LVAD. Biventricular FE analysis showed abnormal motion of the interventricular septum towards the left ventricular free wall, suggesting impaired right heart mechanics. Good agreement between computationally predicted and echocardiographic measured longitudinal strains was found at basal (- 19.1 ± 3.0% for ECHO, and - 16.4 ± 3.2% for FEM), apical (- 20.0 ± 3.7% for ECHO, and - 17.4 ± 2.7% for FEM), and mid-level of the RV free wall (- 20.1 ± 5.9% for echo, and - 18.0 ± 5.4% for FEM). Simulation approach here presented could serve as a tool for less invasive and early diagnosis of the severity of RV failure in patients with LVAD, although future studies are needed to validate our findings against clinical outcomes.

Defining the molecular signatures of human right heart failure

AIMS

Right ventricular failure (RVF) varies significantly from the more common left ventricular failure (LVF). This study was undertaken to determine potential molecular pathways that are important in human right ventricular (RV) function and may mediate RVF.

MATERIALS AND METHODS

We analyzed mRNA of human non-failing LV and RV samples and RVF samples from patients with pulmonary arterial hypertension (PAH), and post-LVAD implantation. We then performed transcript analysis to determine differential expression of genes in the human heart samples. Immunoblot quantification was performed followed by analysis of non-failing and failing phenotypes.

KEY FINDINGS

Inflammatory pathways were more commonly dysregulated in RV tissue (both non-failing and failing phenotypes). In non-failing human RV tissue we found important differences in expression of FIGF, TRAPPAC, and CTGF suggesting that regulation of normal RV and LV function are not the same. In failing RV tissue, FBN2, CTGF, SMOC2, and TRAPP6AC were differentially expressed, and are potential targets for further study.

SIGNIFICANCE

This work provides some of the first analyses of the molecular heterogeneity between human RV and LV tissue, as well as key differences in human disease (RVF secondary to pulmonary hypertension and LVAD mediated RVF). Our transcriptional data indicated that inflammatory pathways may be more important in RV tissue, and changes in FIGF and CTGF supported this hypothesis. In PAH RV failure samples, upregulation of FBN2 and CTGF further reinforced the potential significance that altered remodeling and inflammation play in normal RV function and failure.

The Dark Side of the Moon: The Right Ventricle

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

Acute Biventricular Mechanical Circulatory Support for Cardiogenic Shock

BACKGROUND

Biventricular failure is associated with high in-hospital mortality. Limited data regarding the efficacy of biventricular Impella axial flow catheters (BiPella) support for biventricular failure exist. The aim of this study was to explore the clinical utility of percutaneously delivered BiPella as a novel acute mechanical support strategy for patients with cardiogenic shock complicated by biventricular failure.

METHODS AND RESULTS

We retrospectively analyzed data from 20 patients receiving BiPella for biventricular failure from 5 tertiary-care hospitals in the United States. Left ventricular support was achieved with an Impella 5.0 (n=8), Impella CP (n=11), or Impella 2.5 (n=1). All patients received the Impella RP for right ventricular (RV) support. BiPella use was recorded in the setting of acute myocardial infarction (n=11), advanced heart failure (n=7), and myocarditis (n=2). Mean flows achieved were 3.4±1.2 and 3.5±0.5 for left ventricular and RV devices, respectively. Total in-hospital mortality was 50%. No intraprocedural mortality was observed. Major complications included limb ischemia (n=1), hemolysis (n=6), and Thrombolysis in Myocardial Infarction major bleeding (n=7). Compared with nonsurvivors, survivors were younger, had a lower number of inotropes or vasopressors used before BiPella, and were more likely to have both devices implanted simultaneously during the same procedure. Compared with nonsurvivors, survivors had lower pulmonary artery pressures and RV stroke work index before BiPella. Indices of RV afterload were quantified for 14 subjects. Among these patients, nonsurvivors had higher pulmonary vascular resistance (6.8; 95% confidence interval [95% CI], 5.5-8.1 versus 1.9; 95% CI, 0.8-3.0; P<0.01), effective pulmonary artery elastance (1129; 95% CI, 876-1383 versus 458; 95% CI, 263-653; P<0.01), and lower pulmonary artery compliance (1.5; 95% CI, 0.9-2.1 versus 2.7; 95% CI, 1.8-3.6; P<0.05).

CONCLUSIONS

This is the largest, retrospective analysis of BiPella for cardiogenic shock. BiPella is feasible, reduces cardiac filling pressures and improves cardiac output across a range of causes for cardiogenic shock. Simultaneous left ventricular and RV device implantation and lower RV afterload may be associated with better outcomes with BiPella. Future prospective studies of BiPella for cardiogenic shock are required.

The inodilator levosimendan as a treatment for acute heart failure in various settings

Levosimendan is an inodilator developed for treatment of acute heart failure. It was shown to enhance cardiac contractility, and to exert a vasodilatory effect in all vascular beds. In some trials, the use of levosimendan was associated with cardioprotective effects. These distinctive qualities may be relevant to its use in a range of acute heart failure settings and/or complications, including acute coronary syndromes and cardiogenic shock. It is conjectured that part of the benefit of levosimendan may arise from restoration of ventriculo-arterial coupling via optimization of the ratio of arterial to ventricular elastance and the transfer of mechanical energy. Full confirmation of the effectiveness of levosimendan is still awaited in many of these scenarios; however, the range of potential applications highlights both the versatility of levosimendan and the relative lack of proven interventions in many of these situations.

Benefits of ultra-fast-track anesthesia in left ventricular assist device implantation: a retrospective, propensity score matched cohort study of a four-year single center experience

BACKGROUND

The use of left ventricular assist devices (LVADs) has gained significant importance for treatment of end-stage heart failure. Fast-track procedures are well established in cardiac surgery, whereas knowledge of their benefits after LVAD implantation is sparse. We hypothesized that ultra-fast-track anesthesia (UFTA) with in-theater extubation or at a maximum of 4 h. after surgery is feasible in Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level 3 and 4 patients and might prevent postoperative complications.

METHODS

From March, 2010 to March, 2012, 53 LVADs (50 Heart Mate II and 3 Heart Ware) were implanted in patients in our department. UFTA was successfully performed (LVAD _ultra ) in 13 patients. After propensity score matching, we compared the LVAD _ultra group with a matched group (LVAD _match ) receiving conventional anesthesia management.

RESULTS

Patients in the LVAD _ultra group had significantly lower incidences of pneumonia (p = 0.031), delirium (p = 0.031) and right ventricular failure (RVF) (p = 0.031). They showed a significantly higher cardiac index in the first 12 h. (p = 0.017); a significantly lower central venous pressure during the first 24 h. postoperatively (p = 0.005) and a significantly shorter intensive care unit (ICU) stay (p = 0.016). Kaplan-Meier analysis after four years of follow-up showed no significant difference in survival.

CONCLUSION

In this pilot study, we demonstrated the feasibility of ultra-fast-track anesthesia in LVAD implantation in selected patients with INTERMACS level 3-4. Patients had a lower incidence of postoperative complications, better hemodynamic performance, shorter length of ICU stay and lower incidence of RVF after UFTA. Prospective randomized investigations should examine the preservation of right ventricular function in larger numbers and identify appropriate selection criteria.

Pimobendan in Chronic Right Heart Failure in a Left Ventricular Assist Device Patient

We report the case of a 76-year-old patient who developed chronic right heart failure 1 year after left ventricular assist device implantation due to ischemic cardiomyopathy. Initial recompensation was achieved through dobutamin, sildenafil, and levosimendan treatment. Yet, discharge was successful only after the off-label use of the oral calcium sensitizer pimobendan. Ten months after discharge, the patient presents with no clinical signs of right heart failure and significantly improved right heart function without any impairment in quality of life.

To ventricular assist devices or not: When is implantation of a ventricular assist device appropriate in advanced ambulatory heart failure?

Advanced heart failure has been traditionally treated via either heart transplantation, continuous inotropes, consideration for hospice and more recently via left ventricular assist devices (LVAD). Heart transplantation has been limited by organ availability and the futility of other options has thrust LVAD therapy into the mainstream of therapy for end stage heart failure. Improvements in technology and survival combined with improvements in the quality of life have made LVADs a viable option for many patients suffering from heart failure. The question of when to implant these devices in those patients with advanced, yet still ambulatory heart failure remains a controversial topic. We discuss the current state of LVAD therapy and the risk vs benefit of these devices in the treatment of heart failure.

Chemokine receptor patterns and right heart failure in mechanical circulatory support

BACKGROUND

Right ventricular failure (RVF) complicates 9% to 44% of left ventricular assist device (LVAD) implants post-operatively. Current prediction scores perform only modestly in validation studies, and do not include immune markers. Chemokines are inflammatory signaling molecules with a fundamental role in cardiac physiology and stress adaptation. In this study we investigated chemokine receptor regulation in LVAD recipients who develop RVF.

METHODS

Expression of chemokine receptor (CCR) genes 3 to 8 were examined in the peripheral blood of 111 LVAD patients, collected 24 hours before implant. RNA was isolated using a PAXgene protocol. Gene expression was assessed using a targeted microarray (RT2 Profiler PCR Array; Qiagen). Results were expressed as polymerase chain reaction (PCR) cycles to threshold and normalized to the average of 3 control genes, glyceraldehyde phosphate dehydrogenase (GAPDH), hypoxanthine phosphoribosyltransferase 1 (HPRT1) and β₂-microglobulin (B2M). Secondary outcomes studied were 1-year mortality and long-term RV failure (RVF-LT).

RESULTS

CCR3, CCR4, CCR6, CCR7 and CCR8 were downregulated in LVAD recipients with RVF. Within this cohort of patients, CCR4, CCR7 and CCR8 were further downregulated in those who required RV mechanical support. In addition, under-expression of CCR3 to CCR8 was independently associated with an increased risk of mortality at 1 year, even after adjusting for RVF. CCR expression did not predict RVF-LT in our patient cohort.

CONCLUSIONS

Pre-LVAD CCR downregulation is associated with RVF and increased mortality after implant. Inflammatory signatures may play a major role in prognostication in this patient population.

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.

A Bayesian Model to Predict Right Ventricular Failure Following Left Ventricular Assist Device Therapy

OBJECTIVES

This study investigates the use of a Bayesian statistical model to address the limited predictive capacity of existing risk scores derived from multivariate analyses. This is based on the hypothesis that it is necessary to consider the interrelationships and conditional probabilities among independent variables to achieve sufficient statistical accuracy.

BACKGROUND

Right ventricular failure (RVF) continues to be a major adverse event following left ventricular assist device (LVAD) implantation.

METHODS

Data used for this study were derived from 10,909 adult patients from the Inter-Agency Registry for Mechanically Assisted Circulatory Support (INTERMACS) who had a primary LVAD implanted between December 2006 and March 2014. An initial set of 176 pre-implantation variables were considered. RVF post-implant was categorized as acute (<48 h), early (48 h to 14 daysays), and late (>14 days) in onset. For each of these endpoints, a separate tree-augmented naïve Bayes model was constructed using the most predictive variables employing an open source Bayesian inference engine.

RESULTS

The acute RVF model consisted of 33 variables including systolic pulmonary artery pressure (PAP), white blood cell count, left ventricular ejection fraction, cardiac index, sodium levels, and lymphocyte percentage. The early RVF model consisted of 34 variables, including systolic PAP, pre-albumin, lactate dehydrogenase level, INTERMACS profile, right ventricular ejection fraction, pro-B-type natriuretic peptide, age, heart rate, tricuspid regurgitation, and body mass index. The late RVF model included 33 variables and was predicted mostly by peripheral vascular resistance, model for end-stage liver disease score, albumin level, lymphocyte percentage, and mean and diastolic PAP. The accuracy of all Bayesian models was between 91% and 97%, with an area under the receiver operator characteristics curve between 0.83 and 0.90, sensitivity of 90%, and specificity between 98% and 99%, significantly outperforming previously published risk scores.

CONCLUSIONS

A Bayesian prognostic model of RVF based on the large, multicenter INTERMACS registry provided highly accurate predictions of acute, early, and late RVF on the basis of pre-operative variables. These models may facilitate clinical decision making while screening candidates for LVAD therapy.

Mechanical Circulatory Support and the Role of LVADs in Heart Failure Therapy

Heart failure is epidemic in the United States with a prevalence of over 5 million. The diagnosis carries a mortality risk of 50% at 5 years rivaling many diagnoses of cancer. Heart transplantation, long the “gold standard” treatment for end stage heart failure unresponsive to maximal medical therapy falls way short of meeting the need with only about 2,000 transplants performed annually in the United States due to donor limitation. Left ventricular devices have emerged as a viable option for patients as both a “bridge to transplantation” and as a final “destination therapy”.

Minimally invasive procedures

Minimally invasive procedures, which include laparoscopic surgery, use state-of-the-art technology to reduce the damage to human tissue when performing surgery. Minimally invasive procedures require small "ports" from which the surgeon inserts thin tubes called trocars. Carbon dioxide gas may be used to inflate the area, creating a space between the internal organs and the skin. Then a miniature camera (usually a laparoscope or endoscope) is placed through one of the trocars so the surgical team can view the procedure as a magnified image on video monitors in the operating room. Specialized equipment is inserted through the trocars based on the type of surgery. There are some advanced minimally invasive surgical procedures that can be performed almost exclusively through a single point of entry-meaning only one small incision, like the "uniport" video-assisted thoracoscopic surgery (VATS). Not only do these procedures usually provide equivalent outcomes to traditional "open" surgery (which sometimes require a large incision), but minimally invasive procedures (using small incisions) may offer significant benefits as well: (I) faster recovery; (II) the patient remains for less days hospitalized; (III) less scarring and (IV) less pain. In our current mini review we will present the minimally invasive procedures for thoracic surgery.

Pneumothorax: an up to date "introduction"

The pneumothorax is an abnormal collection of air or gas in the pleural space that separates the lung from the chest wall. Like pleural effusion where a large abnormal concentration of fluid (>100 mL) is liquid buildup in that space, pneumothorax may interfere with normal breathing. A medical term that it is used is the collapsed lung, although that term may also refer to atelectasis. There are two major types of pneumothorax; there is one that occurs without an apparent cause and in the absence of significant lung disease, while the so called; "secondary" pneumothorax occurs in the presence of existing lung pathology. In a minority of cases, the amount of air in the chest increases markedly when a one-way valve is formed by an area of damaged tissue, leading to a third type of pneumothorax, called "tensioned".

Heimlich valve and pneumothorax

The Heimlich valve is a small one-way valve used for chest drainage that empties into a flexible collection device and prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation. Currently there are several systems in the market. It can be used in many patients instead of a traditional water seal drainage system. The Heimlich chest drainage valve was developed so that the process of draining the pleural cavity could be accomplished in a safe, relatively simple, and efficient manner. This valve system has replaced the cumbersome underwater drainage bottle system. Moreover; the Heimlich valve system connects to chest tubing and allows fluid and air to pass in one direction only. This system functions in any position, and it does not ever need to be clamped, a regulated suction can be attached to it if necessary. The valve drains into a plastic bag that can be held at any level, allowing the patient undergoing chest drainage to be ambulatory simply by carrying the bag. In the current mini review we will present the Heimlich valve system and method of insertion.

Pneumothorax as a complication of central venous catheter insertion

The central venous catheter (CVC) is a catheter placed into a large vein in the neck [internal jugular vein (IJV)], chest (subclavian vein or axillary vein) or groin (femoral vein). There are several situations that require the insertion of a CVC mainly to administer medications or fluids, obtain blood tests (specifically the "central venous oxygen saturation"), and measure central venous pressure. CVC usually remain in place for a longer period of time than other venous access devices. There are situations according to the drug administration or length of stay of the catheter that specific systems are indicated such as; a Hickman line, a peripherally inserted central catheter (PICC) line or a Port-a-Cath may be considered because of their smaller infection risk. Sterile technique is highly important here, as a line may serve as a port of entry for pathogenic organisms, and the line itself may become infected with organisms such as Staphylococcus aureus and coagulase-negative Staphylococci. In the current review we will present the complication of pneumothorax after CVC insertion.

Pacemaker insertion

A pacemaker (PM) (or artificial PM, so as not to be confused with the heart's natural PM) is a medical device that uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. The primary purpose of this device is to maintain an adequate heart rate, either because the heart's natural PM is not fast enough, or there is a block in the heart's electrical conduction system. Modern PMs are externally programmable and allow the cardiologist to select the optimum pacing modes for individual patients. Some combine a PM and defibrillator in a single implantable device. PMs can be temporary or permanent. Temporary PMs are used to treat short-term heart problems, such as a slow heartbeat that's caused by a heart attack, heart surgery, or an overdose of medicine. Permanent PMs are used to control long-term heart rhythm problems. A PM can relieve some arrhythmia symptoms, such as fatigue and fainting. A PM also can help a person who has abnormal HRs resume a more active lifestyle. In the current mini review we will focus on the insertion of a PM and the possible pneumothorax that can be caused.