Survival after biventricular assist device implantation: an analysis of the Interagency Registry for Mechanically Assisted Circulatory Support database

Current and future options for adult biventricular assistance: a review of literature

In cardiogenic shock various short-term mechanical assistances may be employed, including an Extra Corporeal Membrane Oxygenator and other non-dischargeable devices. Once hemodynamic stabilization is achieved and the patient evolves towards a persisting biventricular dysfunction or an underlying long-standing end-stage disease is present, aside from Orthotopic Heart Transplantation, a limited number of long-term therapeutic options may be offered. So far, only the Syncardia Total Artificial Heart and the Berlin Heart EXCOR (which is not approved for adult use in the United States unlike in Europe) are available for extensive implantation. In addition to this, the strategy providing two continuous-flow Left Ventricular Assist Devices is still off-label despite its widespread use. Nevertheless, every solution ensures at best a 70% survival rate (reflecting both the severity of the condition and the limits of mechanical support) with patients suffering from heavy complications and a poor quality of life. The aim of the present paper is to summarize the features, implantation techniques, and results of current devices used for adult Biventricular Mechanical Circulatory Support, as well as a glance to future options.

Hypothyroidism Is Associated With Longer Hospital Stay Following Implantation Of Left Ventricular Assist Device

Background:

There has been a steady and consistent rise in the use of left ventricular assist devices in the management of patients with advanced heart failure. Hypothyroidism also remains one of the most common endocrine conditions with a significant impact on the development and overall outcomes of heart failure. The authors analyzed the National Inpatient Sample to evaluate the effect of hypothyroidism on the in-hospital outcomes of patients with end-stage heart failure following the placement of left ventricular assist device.

Methods:

The national inpatient sample was queried to identify all adult patients who had LVAD placement from 2004 to 2014. They were subsequently divided into those with hypothyroidism and those without hypothyroidism. The primary outcome was in-hospital mortality. Other outcomes were acute kidney injury, length, and cost of hospitalization. Logistic regression models were created to determine the outcomes of interest.

Results:

Of 2643 patients in the study, 5.4% had hypothyroidism, and 94.6% did not. The hypothyroid patients were significantly older compared to the non-hypothyroid patients (mean age 58.6 years vs 49.95 years, P-value <.0001). Both groups had similar gender composition. In-hospital mortality was similar across both groups. However, there was a higher incidence of acute kidney injury (AKI) in the hypothyroid group (adjusted odds ratio [aOR 1.83, P-value <.001]). Hypothyroid patients had longer hospital stays (adjusted mean difference [aMD] 5.19, P-value .0001). Hospital charges were also higher in the hypothyroid group.

Conclusion:

This study found that LVAD is associated with longer hospital stay in hypothyroid patients with heart failure.

Contemporary outcomes of continuous-flow biventricular assist devices

Background

Significant right ventricular failure (RVF) complicating left ventricular assist device (LVAD) placement has been reported at 10-30%. Although primarily indicated for left ventricular failure, ventricular assist devices (VADs) have become utilized in a biventricular setup to combat right ventricular failure (RVF) following LVAD implantation. With the advent of continuous-flow LVADs (CF-LVADs) superseding their pulsatile predecessors, the shift towards CF-biventricular assist devices (CF-BiVADs) come with the prospect of improved outcomes over previous pulsatile BiVADs. We aim to review the literature and determine the outcomes of CF-BiVAD recipients.

Methods

A systematic review was performed to determine the outcomes of CF-BiVADs. Pre-operative demographics and device configuration data was collected. Primary outcomes evaluated were short-term survival, long-term survival, duration of support, and survival to transplant. Secondary outcomes evaluated included intensive care unit (ICU) and hospital length of stay (ICU-LOS and HLOS, respectively), pump thrombosis, pump exchange. Median and interquartile range was reported where appropriate. A major limitation was the likely overlap of cohorts across publications, which may have contributed to some selection bias.

Results

Of 1,282 screened, 12 publications were evaluated. Sample size ranged from 4 to 93 CF-BiVAD recipients, and follow-up ranged from 6 to 24 months. Mean age ranged from 34 to 52 years old. Forty-five percent of CF-BiVADs had right atrial (RA-) inflow cannulation, with the remaining being right ventricular (RV). Thirty-day survival was a median of 90% (IQR 82-97.8%) and 12-month survival was a median of 58.5% (IQR 47.5-62%). Where reported, rate of pump thrombosis (predominantly the right VAD) was a median of 31% (IQR 14-36%), although pump exchange was only 9% (IQR 1.5-12.5%).

Conclusions

RVF post-LVAD implantation is a high morbidity and mortality complication. There is no on-label continuous-flow RVAD currently available. Thus, the modifications of LVADs for right ventricular support to combat pump thrombosis has resulted in various techniques. BiVAD recipients are predominantly transplant candidates, and complications of pump thrombosis and driveline infection whilst on wait-list are of great consequence. This study demonstrates the need for an on-label CF-BiVAD.

Weaning from ventricular assist device support after recovery from left ventricular failure with or without secondary right ventricular failure

Although complete myocardial recovery after ventricular assist device (VAD) implantation is rather seldom, systematic search for recovery is worthwhile because for recovered patients weaning from VADs is feasible and can provide survival benefits with long-term freedom from heart failure (HF) recurrence, even if a chronic cardiomyopathy was the primary cause for the drug-refractory HF necessitating left ventricular (LVAD) or biventricular support (as bridge-to-transplantation or definitive therapy) and even if recovery remains incomplete. LVAD patients explanted for myoacardial recovery compared to those transplanted from LVAD support showed similar survival rates and a significant proportion of explanted patients can achieve cardiac and physical functional capacities that are within the normal range of healthy controls. In apparently sufficiently recovered patients, a major challenge remains still the pre-explant prediction of the weaning success which is meanwhile reliably possible for experienced clinicians. In weaning candidates, the combined use of certain echocardiography and right heart catheterization parameters recorded before VAD explantation can predict post-weaning cardiac stability with good accuracy. However, in the absence of standardization or binding recommendations, the protocols for assessment of native cardiac improvement and also the weaning criteria differ widely among centers. Currently there are still only few larger studies on myocardial recovery assessment after VAD implantation. Therefore, the weaning practice relies mostly on small case series, local practice patterns, and case reports, and the existing knowledge, as well as the partially differing recommendations which are based mainly on expert opinions, need to be periodically systematised. Addressing these shortcomings, our review aims to summarize the evidence and expert opinion on the evaluation of cardiac recovery during mechanical ventricular support by paying special attention to the reliability of the methods and parameters used for assessment of myocardial recovery and the challenges met in both evaluation of recovery and weaning decision making.

[Features of the clinical picture and outcomes in patients from a heart transplantation waiting list with different causes of heart failure]

Aim To identify clinical differences between patients on the heart transplant waiting list (HTWL) in the origin of chronic heart failure (CHF).Materials and methods From January 2010 through September 2019, 235 patients (age, 47+13 years (from 10 to 67 years); men, 79% (n=186)) were included in the HTWL. The patients were divided into two groups; group 1 (n=104, 44 %) consisted of patients with ischemic heart disease (IHD); group 2 (n=131, 56 %) included patients with noncoronarogenic CHF. Clinical and instrumental data and frequency of the mechanical circulatory support (MCS) as a "bridge" to heart transplantation (HT) were retrospectively evaluated.Results Group 1 included more male patients than group 2 [97 % (n=101) and 82 % (n=85), р&lt;0.0001]; patients were older (54±8 and 42±14 years, р=0.0001). On inclusion into the HTWL, the CHF functional class was comparable in the groups, III [III;IV]; there were more patients of the UNOS 2 class in group 1 than in group 2 [75 % (n=78) and 57 % (n=75), р=0.005]. Patient distribution in UNOS 1B and 1A classes was comparable in the groups: 21% (n=22) and 3% (n=4) in group 1 and 33 % (n=43) and 10 % (n=13) in group 2. According to echocardiography patients of group 1 compared to group 2 showed a tendency towards higher values of left ventricular ejection fraction (Simpson method) [22 [18;26] % and 19 [15;24] %, р=0.37] and stroke volume [59 [44;72] % and 50 [36;67] %, р=0.07]. Numbers of patients with a cardioverter defibrillator or a cardiac resynchronization device with a defibrillator function were comparable in the groups [35 % (n=36) and 34 % (n=45)]. Comparison of comorbidities in groups 1 and 2 showed higher incidences of pulmonary hypertension [55 % (n=57) and 36 % (n=47), р=0.005], obesity [20 % (n=21) and 10 % (n=13), р=0.03], and type 2 diabetes mellitus [29 % (n=30) and 10 % (n=13), р=0.0004]. Rates of chronic obstructive lung disease, stroke, chronic kidney disease and other diseases were comparable. Duration of staying on the HTWL was comparable (104 [34; 179] and 108 [37; 229] days). During staying on the HTWL, patients of group 1 less frequently required MCS implantation [3 % (n=3) and 28 % (n=21), р=0.0009]. HT was performed for 59 % patients (n=61) in group 2 and 52 % (n=69) patients in group 2. Death rate in the HTWL was lower in group 1 [13 % (n=14) and 27 % (n=35), р&lt;0.01].Conclusion On inclusion into the HTWL, patients with noncoronarogenic CHF had more pronounced CHF manifestations and a more severe UNOS class but fewer comorbidities than patients with CHF of ischemic origin. With a comparable duration of waiting for HT, patients with noncoronarogenic CHD more frequently required MCS implantation and had a higher death rate.

Left ventricular assist devices

Background

There is a growing population of patients in the UK with advanced heart failure who are receiving a left ventricular assist device (LVAD) as a bridge to transplant. This is due to the plateauing number of heart transplantations and the increasing evidence of the effectiveness of these devices. It is, therefore, important that all clinicians working in an intensive care setting have an understanding of how LVADs work, whether as a district general physician referring a patient for consideration of implantation or a tertiary centre healthcare professional managing the complications.

Presentation

This case study describes the journey of a patient presenting with decompensated heart failure who failed to improve despite maximal medical intervention. The patient was not eligible for a heart transplant at the time, so an LVAD was inserted as a bridge to recovery of organ dysfunction and then eventual cardiac transplantation.

Discussion

This article will focus on providing an overview of the indications and anatomy of LVADs as well as the evidence behind their use so that intensive care professionals are aware of the potential of these devices. There will also be further discussion around complications of these devices and practical points to consider when managing a patient who has an LVAD in situ.

Assessing Cerebrovascular Hemodynamics Using Transcranial Doppler in Patients with Mechanical Circulatory Support Devices

BACKGROUND AND PURPOSE

Mechanical circulatory support (MCS) devices are commonly used in heart failure patients. These devices carry risk for presumably embolic and additionally hemorrhagic stroke. Alterations in blood flow play a key role in stroke pathophysiology, and we aimed to learn more about hemodynamic compromise. In this study, we used transcranial Doppler (TCD) ultrasound to define hemodynamics of commonly used nonpulsatile MCS devices, as well as pulsatile devices, with special attention to the total artificial heart (TAH).

METHODS

From 2/2013 through 12/2016, we prospectively enrolled patients with MCS who underwent TCD imaging. We analyzed TCD parameters, including peak systolic velocity, end-diastolic velocity, pulsatility indices (PIs), and number of high-intensity transient signals. Waveform morphologies were compared between various MCS devices.

RESULTS

We performed 132 TCD studies in 86 MCS patients. Waveforms in patients supported by venoarterial-extracorporeal membrane oxygenation demonstrated continuous flow without clear systolic peaks with an average (±SD) PI of .43 (±.2). PIs were low in patients with continuous-flow left ventricular assist devices with a mean PI of .32 (±.13). Impella patients had morphologically distinct pulsatile waveforms and a higher mean PI of .65 (±.24). In intra-arterial balloon pump patients, mean PI was 1.01 (±.16) and diastolic upstrokes were pronounced. In TAH patients, mean middle cerebral artery velocity of 79.69 (±32.33) cm/seconds and PI of .74 (±.14) approached normal values.

CONCLUSION

TCD can detect characteristic waveforms in patients supported by various MCS devices. These device-specific TCD patterns are recognizable and reproducible.

Ventricular arrhythmias in patients with biventricular assist devices

PURPOSE

Ventricular arrhythmias (VAs) are common in patients after left ventricular assist device (LVAD) implant and are associated with worse outcomes. However, the prevalence and impact of VA in patients with durable biventricular assist device (BIVAD) is unknown. We performed a retrospective cohort study of patients with BIVADs to evaluate the prevalence of VA and their clinical outcomes.

METHODS

Consecutive patients who received a BIVAD between June 2014 and July 2017 at our medical center were included. The prevalence of VA, defined as sustained ventricular tachycardia or fibrillation requiring defibrillation or ICD therapy, was compared between BIVAD patients and a propensity-matched population of patients with LVAD from our center. The occurrence of adverse clinical events was compared between BIVAD patients with and without VA.

RESULTS

Of the 13 patients with BIVADs, 6 patients (46%) experienced clinically significant VA, similar to a propensity-matched LVAD population (38%, p = 1.00). There were no differences in baseline characteristics between the two cohorts, except patients in the non-VA group who had worse hemodynamics (mitral regurgitation and right-sided indices), had less history of VA, and were younger. BIVAD patients with VA had a higher incidence of major bleeding (MR 3.05 (1.07-8.66), p = 0.036) and worse composite outcomes (log-rank test, p = 0.046). The presence of VA was associated with worse outcomes in both LVAD and BIVAD groups.

CONCLUSIONS

Ventricular arrhythmias are common in patients with BIVADs and are associated with worse outcomes. Future work should assess whether therapies such as ablation improve the outcome of BIVAD patients with VA.

Utilization and outcomes in biventricular assist device support in pediatrics

OBJECTIVE

Patients with biventricular assist devices (BiVADs) have worse outcomes than those with left ventricular assist devices (LVADs). It is unclear whether these outcomes are due to device selection or patient factors. We used propensity score matching to reduce patient heterogeneity and compare outcomes in pediatric patients supported with BiVADs with a similar LVAD cohort.

METHODS

The Pedimacs registry was queried for patients who were supported with BiVAD or LVAD. Patients were analyzed by BiVAD or LVAD at primary implant and the 2 groups were compared before and after using propensity score matching.

RESULTS

Of 363 patients who met inclusion criteria, 63 (17%) underwent primary BiVAD support. After propensity score matching, differences between cohorts were reduced. Six months after implant, in the BiVAD cohort (LVAD cohort) 52.5% (42.5%) had been transplanted; 32.5% (40%) were alive with device, and 15% (10%) had died. Survival was similar between cohorts (P = .31, log-rank), but patients with BiVADs were more likely to experience a major adverse event in the form of bleeding (P = .04, log-rank). At 1 week and 1 and 3 months' postimplant, the percentage of patients on mechanical ventilation, on dialysis, or with elevated bilirubin was similar between the 2 groups.

CONCLUSIONS

When propensity scores were used to reduce differences in patient characteristics, there were no differences in survival but more major adverse events in the patients with BiVADs, particularly bleeding. Differences in unmatched patient outcomes between LVAD and BiVAD cohorts likely represent differences in severity of illness rather than mode of support.

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.

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.

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.

Short-term mechanical circulatory support as bridge to heart transplantation: paracorporeal ventricular assist device as alternative to extracorporeal life support

Extracorporeal life support (ECLS) is generally considered to be the treatment of choice for bridging to heart transplantation (HTx) patients with cardiogenic shock; however, alternative mechanical circulatory support (MCS) devices have been proposed with satisfactory results and, among those, paracorporeal systems have demonstrated to be safe and effective. This technology has been used for decades as bridge to transplant, especially in patients with advanced right ventricular dysfunction or evidence of multiorgan failure (MOF), which could be difficult to manage with an isolated left ventricular support. Paracorporeal systems are defined by having the pump located outside of the body, with inflow and outflow cannulas that traverse the skin connecting the pump with the heart and great vessels. They can be utilised in a uni- or bi-ventricular configuration and can provide pulsatile or continuous flow, depending on the device technology (pneumatic vs. centrifugal). In particular, pneumatic devices allow for patient mobilization and hospital discharge, improving rehabilitation and organ recovery while bridging to transplant. In our institution at the University Hospital of Udine, 34 pneumatic paracorporeal ventricular assist devices (VADs) have been implanted since 1998: in most cases (32 pts), as biventricular support for patients in INTERMACS class I-II. After a median support time of 34 (range, 0-385) days, with 19 patients (56%) supported for more than 1 month, 23 patients (68%) underwent HTx and 3 (9%) were successfully weaned to hospital discharge, resulting in an overall combined 76% survival to HTx or weaning. After transplant, the survival rate was similar to the one of the patients not bridged with MCS. In conclusion, pneumatic VADs can effectively assist patients with severe biventricular failure, especially those with contraindications to ECLS or expected long waiting times for HTx. Moreover, they can potentially result in hospital discharge, optimal organ and patient recovery and donor-recipient matching, resulting in a satisfactory transplant outcome.

KSHF Guidelines for the Management of Acute Heart Failure: Part III. Specific Management of Acute Heart Failure According to the Etiology and Co-morbidity

The prevalence of heart failure (HF) is on the rise due to the aging of society. Furthermore, the continuous progress and widespread adoption of screening and diagnostic strategies have led to an increase in the detection rate of HF, effectively increasing the number of patients requiring monitoring and treatment. Because HF is associated with substantial rates of mortality and morbidity, as well as high socioeconomic burden, there is an increasing need for developing specific guidelines for HF management. The Korean guidelines for the diagnosis and management of chronic heart failure (CHF) were introduced in March 2016. However, CHF and acute heart failure (AHF) represent distinct disease entities. Here, we introduce the Korean guidelines for the management of AHF with reduced or preserved ejection fraction. Part III of this guideline covers management strategies optimized according to the etiology of AHF and the presence of co-morbidities.

Experience with the SynCardia total artificial heart in a Canadian centre

BACKGROUND

The SynCardia total artificial heart (TAH) provides complete circulatory support by replacing both native ventricles. Accepted indications include bridge to transplantation and destination therapy. We review our experience with TAH implantation during a period when axial flow pump became available.

METHODS

We retrospectively analyzed the demographics, clinical characteristics and survival of all patients receiving the TAH.

RESULTS

From September 2004 to November 2016, 13 patients (12 men, mean age 45 ± 13 yr) received the TAH for refractory cardiogenic shock secondary to idiopathic (56%) or ischemic (17%) cardiomyopathy and to other various causes (33%). Before implantation, mean ejection fraction was 14% ± 4%, 7 (54%) patients had previous cardiac surgery, 4 (31%) were on mechanical ventilation, and 3 (23%) patients were on dialysis. The mean duration of TAH support was 46 ± 40 days. Three (23%) patients died while on support after a mean of 15 days. Actuarial survival on support was 77% ± 12% at 30 days after implantation. Complications on support included stroke (n = 1, 8%), acute respiratory distress syndrome requiring prolonged intubation (n = 5, 38%) and acute renal failure requiring temporary dialysis (n = 5, 38%). Ten (77%) patients survived to be transplanted after a mean of 52 ± 42 days of support. Actuarial survival rates after transplant were 67% ± 16% at 1 month and 56% ± 17% at 1 year after transplantation.

CONCLUSION

The TAH provides an alternative with low incidence of neurologic events in extremely fragile and complex patients waiting for heart transplantation. Complex and unusual anatomic conditions explained the current use of TAH.

Right Ventricular Longitudinal Strain In Left Ventricular Assist Device Surgery-A Retrospective Cohort Study

OBJECTIVES

Right ventricular (RV) failure is common after left ventricular assist device (LVAD) surgery and is associated with higher mortality. Measurement of longitudinal RV strain using speckle-tracking technology is a novel approach to quantify RV function. The authors hypothesized that depressed peak longitudinal RV strain measured by intraoperative transesophageal echocardiography (TEE) examinations would be associated with adverse outcomes after LVAD surgery.

DESIGN

Retrospective cohort study.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Following Institutional Review Board approval, the authors retrospectively identified adult patients who underwent implantation of non-pulsatile LVAD. Exclusion criteria included inadequate TEE images and device explantation within 6 months for heart transplantation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The postoperative adverse event outcome was defined as a composite of one or more of death within 6 months, ≥14 days of inotropes, mechanical RV support, or device thrombosis. Intraoperative TEE images were analyzed for peak RV free wall longitudinal strain by two blinded investigators. Simple logistic regression was used to assess the relationship between adverse outcome and the mean of the strain measurements of the two raters. Agreement between the raters was assessed by intra-class correlation (0.62) and Pearson correlation coefficient (0.63). Of the 57 subjects, 21 (37%) had an adverse outcome. The logistic regression indicated no significant association between RV peak longitudinal strain and adverse events.

CONCLUSIONS

In this retrospective study of patients undergoing non-pulsatile LVAD implantation, peak longitudinal strain of the RV free wall was not associated with adverse outcomes within 6 months after surgery. Additional quantitative echocardiographic measures for intraoperative RV assessment should be explored.

Gastrointestinal bleeding in a patient with a continuous-flow biventricular assist device

The association between continuous-flow left ventricular assist devices (CF-LVADs) and gastrointestinal (GI) bleeding from angiodysplasia is well recognized. However, the association between continuous-flow biventricular assist devices (CF-BIVADs) and bleeding angiodysplasia is less understood. We report a case of GI bleeding from a patient with a CF-BIVAD. The location of GI bleeding was identified by nuclear red blood cell bleeding scan. The vascular malformation leading to the bleed was identified and localized on angiography and then by pathology. The intensity of bleeding, reflected by number of units of packed red blood cells needed for normalization of hemoglobin, as well as the time to onset of bleeding after transplantation, are similar to that seen in the literature for CF-LVADs and pulsatile BIVADs. While angiography only detected a dilated late draining vein, pathology demonstrated the presence of both arterial and venous dilation in the submucosa, vascular abnormalities characteristic of a late arteriovenous malformation.

Novel Scoring System to Predict Ineligibility for Bridge to Implantable Left Ventricular Assist Device as Destination Therapy Before Extracorporeal Ventricular Assist Device Implantation - For the Coming Era of Destination Therapy in Japan

BACKGROUND

Although destination therapy (DT) is now expected to be a promising strategy for those who are not suitable for heart transplantation in Japan, there has not been any investigation into ineligibility for bridging to implantable left ventricular assist device (I-LVAD) as DT among patients with extracorporeal LVAD.

METHODS AND RESULTS

We retrospectively studied 85 patients who had received an extracorporeal LVAD. To assess ineligibility for a bridge to I-LVAD for DT, we defined DT ineligibility (DTI) as BiVAD requirement, death within 6 months, and persistent end-organ dysfunction (medium or high J-VAD risk score) at 6 months after extracorporeal LVAD implantation. DTI was recorded for 32 patients. Uni/multivariate analysis showed that smaller left ventricular diastolic dimension (<64 mm; [odds ratio (OR) 4.522]), continuous hemodiafiltration (OR 4.862), past history of cardiac surgery (OR 6.522), and low serum albumin level (<3.1 g/dl; OR 10.064) were significant predictors of DTI. By scoring 2, 2, 3, 4 points, respectively, considering each OR, we constructed a novel scoring system for DTI (DTI score), which stratified patients into 3 risk strata: low (0-3 points), medium (4-6 points), and high (7-11 points), from the view point of DTI risk (low 8%, medium 46%, high 93%, respectively).

CONCLUSIONS

DTI score is a promising tool for predicting ineligibility for I-LVAD as DT before extracorporeal VAD implantation.

Left ventricular assist device implantation strategies and outcomes

Over the past 15 years, the field of mechanical circulatory support has developed significantly. Currently, there are a multitude of options for both short and long term cardiac support. Choosing the appropriate device for each patient depends on the amount of support needed and the goals of care. This article focuses on long term, implantable devices for both bridge to transplantation and destination therapy indications. Implantation strategies, including the appropriate concomitant surgeries are discussed as well as expected long term outcomes. As device technology continues to improve, long term mechanical circulatory support may become a viable alternative to transplantation.

Comparison of early versus delayed timing of left ventricular assist device implantation as a bridge-to-transplantation: An analysis of the UNOS dataset

BACKGROUND

Placement of left ventricular assist devices (LVAD) as a bridge-to-heart transplantation (HTx) has rapidly expanded due to organ donor shortage. However, the timing of LVAD implantation is variable and it remains unclear if earlier implantation improves survival.

METHODS

We analyzed 14,187 adult candidates from the United Network of Organ Sharing database. Patients were classified by 3 treatment strategies including patients medically treated alone (MED, n=11,009), patients on LVAD support at listing (Early-LVAD, n=1588) and patients undergoing LVAD placement while awaiting HTx (Delayed-LVAD, n=1590). Likelihood of HTx and event-free survival were assessed in patients subcategorized by clinical strategies and UNOS status at listing.

RESULTS

The device support strategy, despite the timing of placement, was not associated with increased likelihood of HTx compared to MED group. However, both LVAD implantation strategies showed better survival compared to MED group (Early-LVAD: HR 0.811 and 0.633, 95% CI 0.668-0.984 and 0.507-0.789, for 1A and 1B; p=0.034 and p<0.001, Delayed-LVAD: HR 0.553 and 0.696, 95% CI 0.415-0.736 and 0.571-0.847, for 1A and 1B; both p<0.001, respectively). Furthermore, there was no significant difference in survival between these LVAD implantation strategies in patients listed as 1B (p=0.500), although Early-LVAD implantation showed worse survival in patients listed as 1A (HR 1.467, 95% CI 1.076-2.000; p=0.015).

CONCLUSION

LVAD support strategies offer a safe bridge-to-HTx. Those candidates who receive urgent upfront LVAD implantation for HTx, and improve to 1B status, would achieve competitive survival with those who receive elective LVAD implantation.

High pulmonary vascular resistance in addition to low right ventricular stroke work index effectively predicts biventricular assist device requirement

Although the right ventricular stroke work index (RVSWI) is a good index for RV function, a low RVSWI is not necessarily an indicator for the need for a right ventricular assist device at the time of left VAD implantation. We here aimed to determine a more precise indicator for the need for a biventricular assist device (BiVAD). In total, 116 patients (mean age, 38 ± 14 years), who underwent hemodynamic assessments preoperatively including 12 BiVAD patients, and had been followed at our institute from 2003 to 2015, were included. Multivariate logistic regression analysis indicated that RVSWI and pulmonary vascular resistance (PVR) were independent predictors of BiVAD requirement (P < 0.05 for both). In addition, all patients were classified into 4 groups: (1) normal (RVSWI > 5 g/m, PVR < 3.7 WU), (2) pulmonary hypertension (RVSWI > 5, PVR > 3.7), (3) RV failure (RVSWI < 5, PVR < 3.7), and (4) both pulmonary hypertension and RV failure (RVSWI < 5, PVR > 3.7), and examined. Most of the patients in Group 4 (75 %), with acutely depressed hemodynamics and inflammatory responses in the myocardium, required BiVAD. Overall, patients with BiVAD had a worse survival rate as compared with those with LVAD alone. In conclusion, high PVR in addition to low RVSWI effectively predicts BiVAD requirement.

Past and Present of Total Artificial Heart Therapy: A Success Story

The totally artificial heart (TAH) is among the most prominent medical innovations of the 21^st century, especially due to the increasing population with end-stage heart failure. The progressive course of the disease, its resistance to conventional therapy, and the scarcity of hearts available for transplantation were the prime impetus for developing a TAH, especially when other options of mechanical circulatory assist devices are exhausted. In this review, we narrate the history of TAH, give an overview of its technology, and address the pros and cons of the currently available TAH models in light of published clinical experience.

Long-term continuous-flow left ventricular assist devices (LVAD) as bridge to heart transplantation

Heart transplantation (HTx) is the treatment of choice for end-stage heart failure but the limited availability of heart's donors still represents a major issue. So long-term mechanical circulatory support (MCS) has been proposed as an alternative treatment option to assist patients scheduled on HTx waiting list bridging them for a variable time period to cardiac transplantation-the so-called bridge-to-transplantation (BTT) strategy. Nowadays approximately 90% of patients being considered for MCS receive a left ventricular assist device (LVAD). In fact, LVAD experienced several improvements in the last decade and the predominance of continuous-flow over pulsatile-flow technology has been evident since 2008. The aim of the present report is to give an overview of continuous-flow LVAD utilization in the specific setting of the BTT strategy taking into consideration the most representative articles of the scientific literature and focusing the attention on the evolution, clinical outcomes, relevant implications on the HTx strategy and future perspectives of the continuous-flow LVAD technology.

Advanced Strategies for End-Stage Heart Failure: Combining Regenerative Approaches with LVAD, a New Horizon?

Despite the improved treatment of cardiovascular diseases, the population with end-stage heart failure (HF) is progressively growing. The scarcity of the gold standard therapy, heart transplantation, demands novel therapeutic approaches. For patients awaiting transplantation, ventricular-assist devices have been of great benefit on survival. To allow explantation of the assist device and obviate heart transplantation, sufficient and durable myocardial recovery is necessary. However, explant rates so far are low. Combining mechanical circulatory support with regenerative therapies such as cell (-based) therapy and biomaterials might give rise to improved long-term results. Although synergistic effects are suggested with mechanical support and stem cell therapy, evidence in both preclinical and clinical setting is lacking. This review focuses on advanced and innovative strategies for the treatment of end-stage HF and furthermore appraises clinical experience with combined strategies.

Biventricular failure with low pulmonary vascular resistance was managed by left ventricular assist device alone without right-sided mechanical support

How to manage preoperative right ventricular dysfunction (RVD) in heart failure patients without cardiogenic shock remains as a matter to be debated because implantable biventricular assist device treatment has not been established thus far. We here presented a patient with significant RVD indicated by low RV stroke work index (0.3 g/m) and RV dilatation as well as low pulmonary vascular resistance (PVR, 0.8 Wood Unit), who was managed by the introduction of pimobendan and sildenafil after the implantation of DuraHeart and tricuspid annuloplasty without right VAD, although his New York Heart Association symptom remained class III. Preoperative low PVR may be a key for successful LVAD treatment alone without right VAD in patients with INTERMACS profile 3 suffering RVD.

A retrospective evaluation of fondaparinux for confirmed or suspected heparin-induced thrombocytopenia in left-ventricular-assist device patients

BACKGROUND

Thrombotic events are a common complication of left ventricular assist device placement and warrant prophylactic anticoagulation. Heparin is the most common anticoagulant used for prophylaxis of thrombotic events in left ventricular assist device patients as a transition to oral anticoagulants but carries the risk of heparin-induced thrombocytopenia. Limited data is available for the treatment of heparin-induced thrombocytopenia in this patient population. We report an evaluation of 8 left ventricular assist device patients with suspected or confirmed HIT started on fondaparinux at the time of heparin-induced platelet-factor-4 antibody positivity.

METHODS

Adult patients were reported if they were heparin-induced platelet antibody positive, tested via enzyme-linked immunusorbent assay, post-operative after left-ventricular assist device, and were initiated on fondaparinux at the time of heparin-induced platelet antibody positivity. Waiver of informed consent was granted from the institutional review board. Baseline demographics, clinical course of HIT, safety and efficacy variables were collected.

RESULTS

Eight patients receiving fondaparinux were identified and included in this report. The patient group was on average 49 years old, weighing 95 kg, with calculated BMI 28.8 and consisted primarily of Caucasian males. Three patients developed new thromboses after initiation of fondaparinux for heparin-induced thrombocytopenia. Only one patient had a major bleeding event of an overt bleed after initiation of fondaparinux therapy.

CONCLUSIONS

Given the lack of major bleeding in this evaluation, fondaparinux could be a potentially safe treatment option for left ventricular assist device patients that are heparin-induced platelet antibody positive pending confirmatory testing results. Given the development of new thromboses in 3 of 8 patients, concern exists about the efficacy of fondaparinux in this patient population. Significant limitations exist regarding these conclusions in this evaluation. Controlled, systematic evaluations are necessary to delineate safety and efficacy of fondaparinux for heparin-induced thrombocytopenia in this population.

Combination evaluation of preoperative risk indices predicts requirement of biventricular assist device

BACKGROUND

Patients with biventricular assist device (BiVAD) placement have a poor prognosis, but preoperative risk factors for the necessity of BiVAD have not been fully elucidated.

METHODS AND RESULTS

Data from 79 patients who received left ventricular assist device (LVAD) between November 2002 and December 2011 were retrospectively reviewed. Overall, 9 patients (11.4%) required BiVAD, and the survival rate of BiVAD patients was significantly lower than that of LVAD patients (P<0.001). Multivariate analysis for BiVAD requirement showed left ventricular diastolic diameter (LVDd) ≤62 mm (odds ratio [OR], 10.97; P=0.009) to be significantly associated with BiVAD requirement. Preoperative central venous pressure (CVP)/pulmonary capillary wedge pressure (PCWP) ratio ≥0.5 (OR, 13.09; P=0.028) was also significantly associated with BiVAD requirement. A new scoring system for predicting BiVAD requirement was created from the combination of CVP/PCWP ratio (≥0.5), body surface area (≤1.4 m(2)), preoperative continuous hemodiafiltration use, B-type natriuretic peptide (≥1,200 pg/ml) and LVDd (≤62 mm), and this had a significantly larger area under the curve (0.909; P=0.003) than right ventricular stroke work index on receiver operating characteristic analysis. A score >20 using the new scoring method indicated significantly high probability of BiVAD requirement (OR, 16.00; P=0.019).

CONCLUSIONS

The new scoring method, which includes CVP/PCWP ratio, is a novel risk stratification tool for BiVAD therapy.