Pulsatile Flow Left Ventricular Assist Devices Research Articles

Successful echocardiography-guided medical management of severe early post-implant right ventricular failure in a patient with left ventricular assist device support: a case report

BackgroundPost-implant right heart failure (RHF) has been recognized as a crucial prognostic factor in patients receiving left ventricular assist devices (LVADs), and its management has long attracted attention from cardiologists and surgeons.Case presentationThis report described an 18-year-old female with acutely deteriorating heart failure due to dilated cardiomyopathy who underwent paracorporeal pulsatile-flow LVAD and developed early post-implant RHF. At postoperative day (POD) six, she was almost asymptomatic at rest on 2.5 mg/kg/min of dobutamine; however, the echocardiogram, performed as part of the daily postoperative care, revealed a severely enlarged right ventricle with a decompressed left ventricle, implying the development of post-implant RHF. Bolus infusion of saline and reduction of pump flow (6.0 L/min to 3.0 L/min) led to normalization of both ventricular shapes in 30 s, suggesting that RHF could be managed without surgical interventions. Milrinone was started on POD six, followed by sildenafil administration on POD seven. Fluid balance was strictly adjusted under the close observation of daily echocardiograms. Milrinone and dobutamine were discontinued on PODs 18 and 21, respectively. The patient was listed for a heart transplant on POD 40. Despite reduced right ventricular function (right ventricular stroke work index of 182.34 mmHg*ml/m− 2, body surface area 1.5 m2), she was successfully converted to implantable LVAD on POD 44 with no recurrence of post-implant RHF thereafter for four years.ConclusionsIn post-implant RHF management, early detection, together with proper and prompt medical management, is crucial to avoiding any surgical intervention. Close observation of daily echocardiograms might be helpful in detecting subclinical RHF and is useful for post-implant medical management.

Recovery after acute kidney injury requiring kidney replacement therapy in patients with left ventricular assist device: A meta-analysis.

BACKGROUNDAcute kidney injury (AKI) is a common and severe complication after left ventricular assist device (LVAD) implantation with an incidence of 37%; 13% of which require kidney replacement therapy (KRT). Severe AKI requiring KRT (AKI-KRT) in LVAD patients is associated with high short and long-term mortality compared with AKI without KRT. While kidney function recovery is associated with better outcomes, its incidence is unclear among LVAD patients with severe AKI requiring KRT. AIMTo identify studies evaluating the recovery rates from severe AKI-KRT after LVAD placement, which is defined by regained kidney function resulting in the discontinuation of KRT. Random-effects and generic inverse variance method of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies.METHODSA total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included. Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo. Kidney recovery occurred in 78% of enrollees at the time of hospital discharge or within 30 d. Overall, the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5% (95%CI: 34.0%-67.0%) at 12 mo follow up. Majority (85%) of patients used continuous-flow LVAD. While the data on pulsatile-flow LVAD was limited, subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1% (95%CI: 36.8%-67.0%). Meta-regression analysis did not show a significant association between study year and AKI recovery rate (P = 0.08). There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.RESULTSA total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included. Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo. Kidney recovery occurred in 78% of enrollees at the time of hospital discharge or within 30 d. Overall, the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5% (95%CI: 34.0%-67.0%) at 12 mo follow up. Majority (85%) of patients used continuous-flow LVAD. While the data on pulsatile-flow LVAD was limited, subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1% (95%CI: 36.8%-67.0%). Meta-regression analysis did not show a significant association between study year and AKI recovery rate (P = 0.08). There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.CONCLUSIONRecovery from severe AKI-KRT after LVAD occurs approximately 50.5%, and it has not significantly changed over the years despite advances in medicine.

Heart, kidney and left ventricular assist device: a complex trio.

Heart failure (HF) is a complex syndrome affecting the whole body, kidneys included. The left ventricular assist device (LVAD) is a valid option for patients with very severe HF. Focusing on renal function, LVAD implantation could theoretically reverse the detrimental effects of HF syndrome on kidneys. However, implanting an LVAD is a high-risk surgical procedure, and LVAD patients have higher risk of bleeding, device thrombosis, strokes, renal impairment, multi-organ failure and infections. Furthermore, an LVAD has its own particular effects on the renal system. In this review, we provide a comprehensive overview of the complex interaction between LVAD and the kidneys from the pathophysiological and clinical perspectives. An analysis of the different effects of pulsatile-flow and continuous-flow LVAD is provided. Despite their limitations, creatinine-based estimated glomerular filtration rate (eGFR) formulas help to stratify patients by their post-LVAD placement prognosis. Poor basal renal function, the onset of acute kidney injury or the need for renal replacement therapy after LVAD implantation negatively influences a patient's prognosis. LVAD can also prompt an improvement in renal function, however, with some counterintuitive effects on a patient's prognosis. It is still hard to say whether different trends in eGFR depend on different renal conditions before LVAD placement, on a patient's better overall status or on a particular patient management strategy before and/or after the device's implantation. Steps should be taken to solve this question because finding the best candidates for LVAD implantation is of paramount importance to ensure the best outcomes.

Left Ventricular Assist Device in Patients with History of Alcohol Abuse or Substance Abuse: An INTERMACS Analysis

<h3>Purpose</h3> In order to understand the impact of history of alcohol and illicit substance abuse on outcomes after left ventricular assist device (LVAD) implantation, we analyzed the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) registry. <h3>Methods</h3> All patients entered into the INTERMACS registry who received a continuous-flow LVAD (CF-LVAD) from June 2006 to December 2017 were included. Patients who had a temporary LVAD, pulsatile-flow LVAD, right ventricular assist device (RVAD), total artificial hearts, or biventricular assist devices were excluded. The Median follow-up duration was 13.3 months (IQR 5.3-28.3). Multivariable Cox proportional hazards model was performed to compare survival in patients with history of alcohol or substance abuse with the rest of the population (control). <h3>Results</h3> There were a total of 15069 patients in the final study group with 1184 patients with history of alcohol abuse and 1139 patients with history of substance abuse. The mean age in alcohol abuse and substance abuse group were 53.3 ± 12.4 (years), and 47.6 ± 12.5 (years), while the mean age in control group was 57.8 ± 12.8 (years). The overall mortality rate during the follow-up in alcohol abuse and substance abuse group were 24.8%, and 21.0%, respectively, compared with 28.7% in control. There was no significant difference in adjusted mortality between the history of alcohol abuse group and control (HR, 0.97, 95% CI, 0.86-1.10, p = 0.62). Similarly, there was no difference between the history of substance abuse group and control (HR, 0.95, 95% CI, 0.83-1.10, p = 0.51) (Figure). <h3>Conclusion</h3> Our findings suggest that patients with history of alcohol abuse or substance abuse have similar mortality rates as control.

New Advances in Monitoring Cardiac Output in Circulatory Mechanical Assistance Devices. A Validation Study in a Porcine Model.

Cardiac output (CO) measurement by continuous pulmonary artery thermodilution (COCTD) has been studied in patients with pulsatile-flow LVADs (left ventricular assist devices), confirming the clinical utility. However, it has not been validated in patients with continuous-flow LVADs. Therefore, the aim of this study was to assess the validity of COCTD in continuous-flow LVADs. Continuous-flow LVADs were implanted in six miniature pigs for partial assistance of the left ventricle. Both methods of measuring CO—measurement by COCTD and intermittent pulmonary artery thermodilution, standard technique (COITD)—were used in four consecutive moments of the study: before starting the LVAD (basal moment), and with the LVAD started in normovolemia, hypervolemia (fluid overloading), and hypovolemia (shock hemorrhage). At the basal moment, COCTD and COITD were closely correlated (r2 = 0.97), with a mean bias of −0.13 ± 0.16 L/min and percentage error of 11%. After 15 min of partial support LVAD, COCTD and COITD were closely correlated (r2 = 0.91), with a mean bias of 0.31 ± 0.35 L/min and percentage error of 20%. After inducing hypervolemia, COCTD and COITD were closely correlated (r2 = 0.99), with a mean bias of 0.04 ± 0.07 L/min and percentage error of 5%. After inducing hypovolemia, COCTD and COITD were closely correlated (r2 = 0.74), with a mean bias of 0.08 ± 0.22 L/min and percentage error of 19%. This study shows that continuous pulmonary thermodilution could be an alternative method of monitoring CO in a porcine model with a continuous-flow LVAD.

Ventricular Assist Device Technology and Black-White Disparities on the Heart Transplant Wait List.

Heart transplantation is the definitive treatment for end-stage heart failure. Left ventricular assist devices (LVADs) are a continually improving technology that extends life for some candidates on the heart transplant waiting list. Research Questions: Our objective is to compare Black-White differences in LVAD implantation and heart transplant outcomes during a period of technological innovation when the pulsatile flow LVAD was largely replaced by the continuous flow LVAD between 1999-2014. We used transplant registry data from the United Network for Organ Sharing (N = 5,550) to identify Black and White patients with heart failure who used an LVAD as a bridge-to-transplant (BTT). Using logistic regression, we compared Black-White differences in access to newer LVAD technology and timing of implantation relative to wait listing for heart transplantation. We used competing-risks event history models to predict transplant outcomes across race, LVAD type, and timing of LVAD implantation. Black and White candidates were equally likely to receive newer continuous flow LVADs, but Black candidates received LVADs later in the disease course (i.e. after transplant listing). This later timing of technological intervention contributed to poorer wait list outcomes among black transplant candidates, including lower likelihood of receiving a heart transplant and greater likelihood of being removed from the wait list due to worsening health. Delayed LVAD implantation is more common among Black patients and is associated with poorer transplant outcomes.

Endothelial Function in Patients With Continuous-Flow Left Ventricular Assist Devices.

The endothelium plays a crucial role in maintaining cardiovascular homeostasis. Shear stress generated by flowing blood regulates the release of substances that provide adequate tissue perfusion. The extent of damage to endothelial cells depends on locally disturbed shear stress caused by the deteriorated flow. Patients with heart failure have reduced cardiac output, which results in reduced blood flow and negative shear stress. Reduced shear stress also affects microcirculation and reduces tissue perfusion. Consequently, the production of free oxygen radicals is increased and bioavailability of nitric oxide is additionally decreased. Therefore, endothelial dysfunction is involved in the progression of heart failure and cardiovascular events. Left ventricular assist devices (LVAD) are used for the treatment of patients with advanced heart failure. Older pulsatile flow LVADs were mostly substituted by continuous-flow LVADs (cf-LVADs). Despite the advantages of the cf-LVADs, the loss of pulsatility leads to different complications on the micro- and macrovascular levels. One of the pathogenetic mechanisms of cardiovascular complications with cf-LVADs may be endothelial dysfunction, which after the implantation of the device does not improve and may even deteriorate. In contrast, the pulsatile pattern of LVADs on blood flow could preserve endothelial function.

Gastrointestinal Bleeding After HeartMate II or HVAD Implantation: Incidence, Location, Etiology, and Effect on Survival.

The number of patients on destination therapy is increasing as long-term survival on continuous-flow left ventricular assist device (CF-LVAD) therapy has improved. Gastrointestinal bleeding (GIB) is a common complication after CF-LVAD implantation, and its risk correlates with longer support time, emphasizing the importance of GIB management. The lower pulsatility of CF-LVADs may promote arteriovenous malformations, which amplify the bleeding risk. Here, we retrospectively analyzed the location, incidence, and survival effect of GIB events in HeartMate II (HM-II) and HeartWare Ventricular Assist Device (HVAD) recipients to provide specific details regarding these complications. From November 2003 to March 2016, 526 patients with chronic heart failure underwent primary implantation of an HM-II (n = 403) or HVAD (n = 123) CF-LVAD at our center. Of the 526 patients, 140 (26.6%) had a GIB event (HM-II: n = 100; HVAD: n = 40), 92 (17.5%) had a single GIB event, and 48 (9.1%) had multiple GIB events (range: 2-9 events). HVAD recipients had a higher incidence of both upper and lower GIB events (p < 0.001 and P = 0.002, respectively) than HM-II recipients. Arteriovenous malformation was the most common etiology for GIB (50 patients/72 events); for this group, the average time-to-event was 300.4 days, the recurrence rate was 34%, and the 90-day and 1-year survival rates were 88.3% and 66.7%, respectively. Age at implantation was the only predictor of GIB. In conclusion, our study provides detailed information about GIB events associated with current CF-LVADs. Additional studies are required to evaluate strategies to reduce the incidence of GIB morbidity.

Estimation of Systemic Vascular Resistance Using Built-In Sensing From an Implanted Left Ventricular Assist Device

Abstract This paper presents an approach for real-time estimation of the systemic vascular resistance (SVR) of heart failure patients who have a left ventricular assist device (LVAD). Notably, an approach is described that relies only on sensing that is built into the LVAD, so no additional sensors or measurements are required. The estimation of SVR is accomplished using a variant of the extended Kalman filter (EKF) algorithm, making use of a reduced-order systemic circulation model, and requires LVAD flowrate as an input to the systemic circulation and measurement of the LVAD differential pressure. Experiments using a hybrid mock circulatory loop (hMCL) are used to show the efficacy of this approach for both types of LVAD pumping modalities; i.e., continuous flow (CF) turbomachines and pulsatile flow (PF) positive-displacement pumps. The mock loop uses a real-time hardware-in-the-loop simulation of the cardiovascular system (CVS) where physiological parameters and particularly the SVR can be set to known values, allowing a basis for evaluating the accuracy of the estimation algorithms. It was found that SVR value estimates were accurate within 1.3% and 0.7% compared to the set model values for the continuous and PF LVADs, respectively. The use of this SVR estimation approach utilizing built-in LVAD sensing technology has potential for use in further real-time estimation endeavors, monitoring of patient physiology, and providing alerts to physicians.

Effect of Continuous-Flow Mechanical Circulatory Support on Microvasculature Remodeling in the Failing Heart.

Left ventricle (LV) unloading caused by a left ventricular assist device (LVAD) has been shown to enhance reverse LV remodeling in end-stage cardiomyopathy. Several reports consistently suggest that a pulsatile-flow LVAD has more profound effects compared to continuous-flow LVAD, though the responsible mechanisms are not fully understood. We hypothesized that arterial pulsatility, being affected by the type of LVAD, may affect microvasculature and functional/pathological LV remodeling in end-stage cardiomyopathy. The study included 18 patients with chronic heart failure who underwent LVAD implantation. Eight patients were implanted with pulsatile-flow LVAD, and 10 patients were implanted with continuous-flow LVAD. The results of serial echocardiograms and histopathological assessment of transmural LV tissues, which were collected during the implantation and removal of LVADs, were compared between the groups. The results of echocardiography showed that LV systolic dimension and LV ejection fraction improved greatly in the pulsatile-flow LVAD group compared to the continuous-flow LVAD group. Histological analysis showed that in both groups, increased microvasculature density and decreased cardiomyocyte size during LVAD support had no significant difference. In contrast, only the patients with continuous-flow LVADs had presented with significant increase in α-smooth muscle actin (α-SMA)-positive layer thickness and the number of proliferating cell nuclear antigen (PCNA)-positive cells of myocardial arterioles. We concluded that the use of long-term continuous-flow LVAD support, having less pulsatility, had induced more thickening to the medial layer of myocardial arterioles compared to the use of pulsatile-flow LVADs. Our findings suggest that the pathological impairment of myocardial microvascular structure during continuous-flow LVAD support may be a novel mechanism which accounts for the difference in LV remodeling depending on the type of LVAD.

QRS Shortens after Left Ventricular Assist Device Implantation

QRS Shortens after Left Ventricular Assist Device Implantation

Acute and Long-Term Effects of LVAD Support on Right Ventricular Function in Children with Pediatric Pulsatile Ventricular Assist Devices.

Right ventricular failure (RVF) is a significant issue when considering left ventricular assist device (LVAD) implantation in pediatrics. The aim of this study was to evaluate the effects of LVAD on right ventricular (RV) function in children. We retrospectively reviewed clinical and echocardiographic data of children who underwent Berlin Heart EXCOR LVAD focusing on RV function before and after implantation (1, 3, and 6 month follow-up). An isolated LVAD was used in 27 patients. Median age was 11 months (interquartile range [IQR]: 5-24 months), with a median weight of 6.3 kg (IQR: 5-9 kg). Median time on ventricular assist device (VAD) support was 147 days (IQR: 86-210 days). Twenty patients were successfully bridged to orthotopic heart transplantation (OHT) (74%), six patients died (22%), and also heart function recovered in one patient (4%). Before LVAD implantation, nine patients (33%) showed a RV fractional area change (RVFAC) less than or equal to 30%. After implantation, mean RVFAC increased up until the 3 month follow-up (43.13%; p = 0.033) and then slightly decreased. In a subgroup of 18 patients, the average strain value increased after the 1 month follow-up (p = 0.022). Right ventricular failure developed in 33% of patients before the 1 month follow-up, and 7.4% experienced RVF at the 6 month follow-up. No patient required biventricular assist device (BiVAD). In our population, pulsatile-flow LVAD in children allows optimal RV decompression and function post-LVAD as measured by improvement in RV function at echo particularly at 1 and 3 month follow-up. At long-term follow-up, the beneficial effects of LVAD on RV function seem to be reduced as signs and symptoms of late RVF may develop in some patients despite LVAD support.

Mechanical Circulatory Support for Advanced Heart Failure: Are We about to Witness a New "Gold Standard"?

The impact of left ventricular assist devices (LVADs) for the treatment of advanced heart failure has played a significant role as a bridge to transplant and more recently as a long-term solution for non-eligible candidates. Continuous flow left ventricular assist devices (CF-LVADs), based on axial and centrifugal design, are currently the most popular devices in view of their smaller size, increased reliability and higher durability compared to pulsatile flow left ventricular assist devices (PF-LVADs). The trend towards their use is increasing. Therefore, it has become mandatory to understand the physics and the mathematics behind their mode of operation for appropriate device selection and simulation set up. For this purpose, this review covers some of these aspects. Although very successful and technologically advanced, they have been associated with complications such as pump thrombosis, haemolysis, aortic regurgitation, gastro-intestinal bleeding and arterio-venous malformations. There is perception that the reduced arterial pulsatility may be responsible for these complications. A flow modulation control approach is currently being investigated in order to generate pulsatility in rotary blood pumps. Thrombus formation remains the most feared complication that can affect clinical outcome. The development of a preoperative strategy aimed at the reduction of complications and patient-device suitability may be appropriate. Patient-specific modelling based on 3D reconstruction from CT-scan combined with computational fluid dynamic studies is an attractive solution in order to identify potential areas of stagnation or challenging anatomy that could be addressed to achieve the desired outcome. The HeartMate II (axial) and the HeartWare HVAD (centrifugal) rotary blood pumps have been now used worldwide with proven outcome. The HeartMate III (centrifugal) is now emerging as the new promising device with encouraging preliminary results. There are now enough pumps on the market: it is time to focus on the complications in order to achieve the full potential and selling-point of this type of technology for the treatment of the increasing heart failure patient population.

Abstract 12162: Changes in Renal Function Following Left Ventricular Assist Device Placement in Pediatric Patients: A PediMACS Analysis

Introduction: Renal dysfunction (RD) is prevalent among pediatric patients with advanced heart failure. Data are limited regarding changes in renal function following left ventricular assist device (LVAD) placement in this population. Hypothesis: Renal function will improve following pediatric LVAD placement, but degree and durability of improvement may vary based upon patient and device characteristics. Methods: Pediatric LVAD recipients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS) between September 19, 2012 and December 31, 2015 were included. The Schwartz equation was used to calculate eGFR and longitudinal changes in renal function were analyzed for the entire cohort as well as subgroups stratified by patient and device characteristics. Results: Data from 218 patients from 39 centers were analyzed. Mean age at implant was 9.2 years and total follow up time was 768 patient-months. There were 117 (54%) durable continuous flow LVADs, 60 (27%) durable pulsatile flow LVADs, and 41 (19%) temporary LVADs. The underlying diagnosis was cardiomyopathy in 162 (74%) patients and congenital heart disease in 47 (22%) patients. Baseline RD (eGFR &lt; 90 mL/min/1.73 m 2 ) was present in 140 (64%) patients. Overall, eGFR improved post-LVAD, peaking at 1 month post-implant (Figure 1). There was an inverse relationship between baseline eGFR and the degree of improvement at 1 month (mean increase in eGFR of 45 +/- 16 for patients with baseline RD vs. mean increase of 16 +/- 58 for patients with normal eGFR pre-LVAD, p=0.001). Degree of improvement in eGFR at 1 month did not appear impacted by device type, age, or diagnosis. There was a downward trend in eGFR after 1 month, although eGFR remained over baseline for patients with pre-implant RD. Conclusions: Renal function improves post-LVAD placement in pediatric patients regardless of age, diagnosis or device type, with improvement most pronounced in patients with baseline RD.

Acute Biventricular Interaction in Pediatric Patients Implanted with Continuous Flow and Pulsatile Flow LVAD: A Simulation Study.

Left ventricular assist devices (LVADs) are used to bridge pediatric patients till transplantation. However, the LVADs effects on right ventricular (RV) function are controversial. This work aims at studying the ventricular interdependency in the presence of continuous (c-) and pulsatile (p-) flow LVAD in pediatric patients using a lumped parameter model including the representation of the septum. Five pediatric patients' data were used to simulate patients' baseline. The effects on LV and RV functions, energetics, preloads and afterloads of different c-LVAD speeds, p-LVAD rate, p-LVAD systole duration, p-LVAD filling and ejection pressures were simulated. c-LVAD and p-LVAD unload the LV decreasing the LV external work and improving the LV ventriculo-arterial coupling and these effects are more evident increasing the c-LVAD speed and the p-LVAD rate. Continuous-LVAD and p-LVAD decrease the RV afterload, increase the RV ejection fraction and improve the RV ventriculo-arterial coupling. The changes in RV function are inversely proportional to the degree of the interventricular septum leftward shift that increased by increasing the LVAD contribution. The study of the interventricular interaction could lead to the development of a dedicated algorithm to optimize LVAD setting in pediatric population.

Abstract WMP54: Cerebrovascular Accidents in Patients With a Left Ventricular Assist Device

Background: Cerebrovascular accidents (CVAs), including ischemic stroke, transient ischemic attack, and intracranial hemorrhage, are major and devastating complications of left ventricular assist devices (LVADs). However, little is known about their incidence and risk factors. Materials and methods: We retrospectively reviewed the medical records of 75 consecutive cases supported with a LVAD (mean age of 39 years, 60 men, paracorporeal pulsatile-flow LVAD in 31, implantable centrifugal-flow in 18, and implantable axial-flow in 26) in our institution between December 2009 and June 2014. The incidence rate of CVAs was estimated as events per patient-year, and baseline characteristics (age, sex, etiologies of heart failure, comorbid diseases, and types of LVAD) were assessed to determine their contribution to the incidences of total, ischemic and hemorrhagic CVAs. Results: During 113.7 patient-years of observation, a total of 59 CVA events (26 hemorrhagic and 33 ischemic) were identified in 31 cases, yielding an incidence rate of 0.52 events per patient-year. Univariate negative binomial regression (NBR) analysis demonstrated that patients with an axial-flow LVAD had significantly lower incidence of total CVAs [incidence rate ratio (IRR) 0.29, 95% confidence interval (CI) 0.10 - 0.88, p=0.03] and subsignificantly of both of ischemic (0.30, 0.05 - 1.69, p=0.17) and hemorrhagic CVAs (0.29, 0.08 - 1.02, p=0.05) than those with a paracorporeal LVAD (reference), whereas those with a centrifugal-flow LVAD did not. Patients with diabetes had a significantly higher incidence of total CVAs (IRR 2.39, 95% CI 1.03 - 5.57, p=0.04) and ischemic CVAs (4.01, 1.31 - 12.2, p=0.02) than those without diabetes but not of hemorrhagic CVAs (1.41, 0.54 - 3.66, p=0.48). Results of multivariate NBR analysis were similar with those of univariate analysis. Conclusion: Among patients on LVAD support, CVA occurred at a rate of 0.52 events per patient-year. Axial-flow LVADs reduced the incidence of CVAs, regardless of ischemic or hemorrhagic subtype, compared with paracorporeal LVADs. Diabetes was associated with an increased risk of CVAs, but the influence was different between ischemic and hemorrhagic CVAs.

Preoperative Prediction of Aortic Insufficiency During Ventricular Assist Device Treatment

Survival rate in patients with stage D heart failure has improved significantly owing to the development of continuous flow left ventricular assist devices (LVAD), but aortic insufficiency (AI) still remains one of the major unsolved complications that impairs patient quality of life. There are no established treatments for AI, and preoperative prediction and prevention of AI is needed. The opening of a native aortic valve (AV) is a sufficient condition for prevention of AI, and improvement of LV ejection fraction due to LV reverse remodeling (LVRR) is essential to open a native AV. Preoperative insufficient β-blocker treatment and pulsatile flow LVAD usage are keys for LVRR, opening of an AV, and prevention of AI. The second mechanism that leads to AI is remodeling of the aortic root and degeneration of a native AV, which results from reduced pulse pressure during LVAD support. Centrifugal or pulsatile flow LVAD usage has an advantage in terms of preserving pulsatility, and may prevent AI compared with an axial pump. There is less probability of avoiding AI with sufficient β-blocker treatment, and these patients may be good candidates for concomitant surgical intervention to a native AV at the time of LVAD implantation.

Risk Factors and Outcomes of Gastrointestinal Bleeding in Left Ventricular Assist Device Recipients

Increasing use of left ventricular assist devices (LVADs) has been accompanied by rising incidence of gastrointestinal bleeding (GIB). Objectives of this study were to determine the yearly incidence of GIB in LVAD recipients, compare outcomes of continuous-flow (CF) and pulsatile-flow LVAD eras, and investigate for risk factors. The Healthcare Cost and Utilization Project-Nationwide Inpatient Sample database from 2005 to 2010 was analyzed. Primary outcome of interest was incidence of GIB in LVAD recipients. Multivariate logistic regression model was used to examine independent associations of GIB with risk factors and outcomes. An estimated 8,879 LVAD index admissions and 8,722 readmissions in LVAD recipients over 6 years were analyzed. The yearly incidence of GIB after LVAD implantation increased from 5% in 2005 to 10% in 2010. On multivariate regression analysis, the odds of GIB was 3.24 times greater (95% confidence interval 1.53 to 6.89) in the era of CF LVADs than in the era of pulsatile-flow LVADs. Compared to their younger counterparts, in LVAD recipients aged >65 years, the adjusted odds of GIB was 20.5 times greater (95% confidence interval 2.24 to 188). GIB did not significantly increase the inhospital mortality but increased the inpatient length of stay. In conclusion, the incidence of GIB in LVAD recipients has increased since the use of CF LVADs has increased, leading to greater inpatient lengths of stay and hospital charges. Older recipients of CF LVADs appear to be at a greater risk of GIB.

Right ventricular assist device results in worse post-transplant survival

To our knowledge, how the need for a right ventricular assist device (RVAD) with a left ventricular assist device (LVAD) affects outcomes after orthotopic heart transplantation has not been studied in a multi-institutional database. The United Network for Organ Sharing (UNOS) database was queried for all adult orthotopic heart transplantations from the period 2005-2012. Patients requiring a RVAD + LVAD as a bridge to transplant were compared with patients requiring a LVAD only and patients requiring no ventricular assist device (VAD). During the study period, 16,955 orthotopic heart transplantations were performed. Of these, 13,209 (77.9%) patients did not require a VAD, 3,270 (19.3%) required a LVAD only, and 457 (2.7%) required a RVAD + LVAD. The RVAD + LVAD group had the longest length of stay (25.7 days) compared with the no VAD group (20.8 days) and the LVAD-only group (21.1 days) (p < 0.001). On multivariate analysis, requirement of a RVAD + LVAD before transplantation was independently associated with post-transplant mortality (hazard ratio 1.22, 95% confidence interval 1.01-1.49, p = 0.04). Other variables associated with mortality included donor age, pulsatile flow LVAD as a bridge to transplant, prolonged ischemic time, worsening renal function, black race, history of diabetes in recipient, class II panel-reactive antibody >10%, sex mismatch, and extracorporeal membrane oxygenation or mechanical ventilation as a bridge to transplant. The requirement of a RVAD in addition to a LVAD before orthotopic heart transplantation is associated with worse post-transplant outcomes and increased mortality.

Towards destination therapy with left ventricular assist devices in Japan.

Medical and electrical therapies for systolic heart failure have improved outcomes and altered the natural history of the disease. Although heart transplantation remains the most successful treatment option for patients with advanced heart failure refractory for these treatment, cardiac transplantation is available for only a minority of patients because of the lack of suitable donor hearts. As a consequence of limited donor availability, left ventricular assist device (LVAD) therapy has become an established treatment for patients with advanced heart failure as either a bridge to transplantation (BTT) or as a permanent alternative to transplantation, i.e., destination therapy (DT). The Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial provided a firm albeit inauspicious proof of concept for the use of blood pumps as an alternative to medical therapy in patients not eligible for transplantation. Small continuous-flow LVADs improved the probability of survival and reduced the risk of device failure compared to larger pulsatile-flow LVADs. Axialflow LVADs have been the most popular option for mechanical circulatory support. Along with axial-flow blood pumps, some centrifugal blood pumps have also been developed aiming at achieving mechanical circulatory support as well as long-term durability.