Left Ventricular Assist Devices Type Research Articles

Prevalence of Gastrointestinal Bleeding among Patients with Left Ventricular Assist Devices: A Systematic Review

Purpose: Gastrointestinal bleeding (GIB) is increased in patients with left-ventricular assist devices (LVADs), likely due to increased formation of angiodysplastic lesions (AVMs) from an acquired von-Willebrand's deficiency. We performed a systematic review in order to assess the prevalence of GIB in patients with LVADs. Methods: A literature search was conducted using Pubmed and SCOPUS from 1990-2013 using the terms “left ventricular assist device,” “gastrointestinal bleeding,” “upper endoscopy,” “colonoscopy,” “capsule endoscopy,” and/or “deep enteroscopy.” Articles were included if they contained information regarding GIB in LVAD patients. We excluded case reports. Summary statistics were performed for the key variables of the included articles including mean age, gender, type of LVAD, usage of anticoagulation, presence of other co-morbid conditions, and mortality. Results: The literature search resulted in 229 articles. After exclusion of duplicates, case reports, and review articles, we included 15 papers. Table 1 demonstrates demographic features for LVAD patients with and without GIB. While there were no significant differences in age, gender, or race, patients with GIB were more likely to have continuous-flow LVADs, ischemic cardiomyopathy, and non-transplant status. History of prior GIB and chronic renal insufficiency were risk factors for subsequent bleeding. Aspirin, anti-platelet, oral anticoagulant, and proton pump inhibitor use were not significantly associated with bleeding. Table 2 demonstrates the prevalence of GIB, recurrence rates, and type of bleeding from the 13 studies where this data was available. GIB occurred in 223/1053 (23%) of continuous-flow LVAD patients with recurrence rates of 8%. Based on data from 8 papers, there were an average of 32 GIB episodes per study, or 0.4 per patient. Prevalence data was reported in 5 studies and included upper GIB in 49%, lower GIB in 26%, and mid-gut in 24%. AVMs were the cause of GIB in 40% based on 7 studies, and the mean time to bleeding was 86 days post-LVAD placement. Overall mortality was 24%, and was not higher in the GIB cohort.Table 1: Demographic features of LVAD patients with GIBTable 2: Characteristics of LVAD patients with gastrointestinal bleedingaConclusion: This systematic review demonstrated that GIB occurred in approximately one-quarter of patients receiving LVAD placement. The rate of GIB was much higher following continuous-flow as compared to pulsatile-flow LVAD placement. Non-transplant status, ischemic cardiac disease, history of GIB, and chronic kidney insufficiency were significantly associated with GIB. While nearly half of the patients had bleeding sources found in the upper GI tract, small bowel sources were detected in one quarter of the patients. AVMs were more common in the LVAD population compared to patients with GIB in the general population.

Fyn Plays a Critical Role in Regulating Apoptosis of Cardiac Myocyte in Failing Heart through Tyrosine-phosphorylation of Nox4

Background: Thus far, continuous flow (CF) left ventricular assist device (LVAD) has replaced pulsatile flow (PF) LVAD because of its advantage in better patients sur- vival and higher quality of life. However, effect on left ventricular (LV) reverse re- modeling between both types of LVAD has not been analyzed well. Methods and Results: We retrospectively analyzed 52 patients with stage D heart failure due to dilated cardiomyopathy who had received LVAD implantation (PF type, 22; CF type, 30) and been followed for 6 months after the surgery. We defined LV reverse remodeling as the following criteria; C1: %change in LV ejection fraction (EF) O0% (17 patients (32.7%) accomplished) or C2: achieved LVEF O35% (15 patients (28.8%) accomplished) at 6 months after LVAD implantation. Univariable logistic re- gression analyses for LV reverse remodeling demonstrated that PF LVAD usage was an only independent predictive factor for each C1 and C2 among preoperative vari- ables including demographic, echocardiographic, and hemodynamic parameters. Pa- tients who accomplished C1 or C2 had less aortic valve insufficiency and lower plasma BNP at 6 months after the surgery. Three patients (5.8%), in whom LVADs were explanted, all implemented both C1 and C2. Conclusions: PF LVAD may have an advantage in LV reverse remodeling compared with CF LVAD.

Pulsatile Flow Ventricular Assist Device Has Advantage for Reverse Remodeling of Left Ventricle

Thus far, continuous flow (CF) left ventricular assist device (LVAD) has replaced pulsatile flow (PF) LVAD because of its advantage in better patients survival and higher quality of life. However, effect on left ventricular (LV) reverse remodeling between both types of LVAD has not been analyzed well.

Comparison of Continuous‐Flow and Pulsatile‐Flow Blood Pumps on Reducing Pulmonary Artery Pressure in Patients With Fixed Pulmonary Hypertension

Pulmonary hypertension (PH) is considered as a risk factor for morbidity and mortality in patients undergoing heart transplantation. Recently, left ventricular assist device (LVAD) implantation has been increasingly used in reducing pulmonary artery pressure (PAP) in patients with PH unresponsive to medical therapy. Herein, we aimed to compare the efficacy of continuous-flow and pulsatile-flow blood pumps on the improvement of PH in mechanical circulatory support patients. Twenty-seven patients with end-stage heart failure who underwent LVAD implantation surgery were enrolled. Fifteen of them (55.6%) had continuous-flow pump (HeartWare Ventricular Assist System, HeartWare, Inc., Miramar, FL, USA), and 12 of them (44.4%) had pulsatile pump (Berlin Heart EXCOR ventricular assist device, Berlin Heart AG, Berlin, Germany). The efficacy of LVADs on the improvement of PH was compared between continuous-flow and pulsatile pumps by the evaluation of systolic PAP, tricuspid annular plane systolic excursion (TAPSE), right ventricular systolic motion (RVSM), right ventricular ejection fraction (RVEF), and grade of tricuspid insufficiency (TI) for each of the study participants. All of the 15 patients who underwent continuous-flow blood pump implantation surgery (Group 1) were male with a mean age of 46.9 ± 11.7 years, and in pulsatile-flow blood pump implanted participants (Group 2), the mean age was 40.6 ± 16.8 years, all of whom were also male (P=0.259). Mean follow-up was 313.7 ± 241.3 days in Group 1 and 448.7 ± 120.7 days in Group 2 (P=0.139). In Group 1, mean preoperative and postoperative systolic PAP were measured as 51.7 ± 12.2 mm Hg and 22.2 ± 3.4 mm Hg, respectively, while those in Group 2 were 54.5 ± 7.5 mm Hg and 33.9 ± 6.4 mm Hg, respectively. A significantly greater decrease in systolic PAP was noticed in patients with continuous-flow blood pumps (P=0.023); however, no statistically significant difference was found when we considered the change in TAPSE between study groups (P=0.112). A statistical significance in the alteration of RVEF, RVSM, and the grade of TI during study visits was not found between the study groups (P=0.472, P=0.887, and P=0.237, respectively). Although the two studied types of LVADs were found to be effective in reducing PAP in heart transplantation candidates with PH, lesser postoperative systolic PAP values were achieved in patients who underwent continuous-flow pump implantation surgery.

Pulseless Angiography

A left ventricular assist device (LVAD) is a mechanical device that can be placed in a patient with left ventricular functional compromise as a means to improve cardiac function. Typically, blood is pumped out from the ventricular apex, through the LVAD, and then back into the aorta via a cannula. The Figure is a surface-rendered three-dimensional reconstruction from a computed tomographic angiogram in a patient with a HeartMate II LVAD (Thoratec, Pleasanton, California). Use of the different types of LVADs result in continuous or pulsatile flow (Table).

Cerebrovascular complications of left ventricular assist devices

Left ventricular assist devices (LVADs) are increasingly being used as a bridge to heart transplantation or destination therapy. It is unclear which antithrombotic regimen should be used to reduce the risk of stroke. We systematically reviewed the literature on all types of antithrombotic regimens and stroke in patients with any type of LVADs. Our primary outcome measure was the mean incidence of any type of stroke. Twenty-six articles were selected as relevant, comprehending 1989 patients with a mean LVAD support of 200 days (range 30-621). The mean proportion of patients affected with stroke was 20% (range 0-55%), with a mean incidence of 0.74 (range 0-6.91) events/patient-year. Support with HeartMate II and a regimen of postoperative heparin converted to coumarins, acetylsalicylic acid (ASA) and dipyridamole resulted in 0.17 (mean; range 0.06-0.29) strokes/patient-year. HeartMate II support and the same regime without heparin was associated with 0.07 (mean; range 0.03-0.11) strokes/patient-year. A Novacor device with heparin, converted to coumarins, was associated with 3.82 (mean; range 1.03-6.91) strokes/patient-year, while ASA added to this regime resulted in 0.97 ischaemic strokes/patient-year (mean; range 0.53-1.48). Other combinations of assist devices and antithrombotic regimes were investigated in one or two studies only. This systematic review provides risk estimates for stroke for various LVADs and antithrombotic regimes. Our findings indicate that the postoperative use of heparin in HeartMate II patients is doubtful, and suggest an important role for antiplatelet drugs to prevent stroke in patients supported with a Novacor device.

Imaging for Ventricular Function and Myocardial Recovery on Nonpulsatile Ventricular Assist Devices

Advances in the field of device support have led to increased use of continuous-flow left ventricular assist devices (LVADs) to improve outcomes in patients with end-stage heart disease. Newer-generation LVADs have become the pump of choice for bridging to heart transplantation and as destination therapy for patients with contraindications to transplantation.1 Different imaging modalities have played a major role in LVAD preoperative, early postoperative, and long-term follow-up management. The primary imaging modality to monitor patients with continuous-flow LVADs is echocardiography. The present review highlights the role of echocardiography and the other imaging modalities in the assessment of ventricular size and function, intracardiac hemodynamics, and myocardial recovery of patients with continuous-flow LVADs. The evolving role of echocardiography in facilitating the identification of optimal pump speed settings in patients supported by continuous-flow LVADs will be discussed, along with a summary of the protocol we use for image acquisition and reporting. Furthermore, we will provide a summary of echocardiographic findings associated with continuous-flow LVAD-related complications and device dysfunction. Second-generation continuous-flow LVAD rotary pumps offer several advantages over pulsatile first-generation pumps, including smaller size and, importantly, greater long-term mechanical reliability. The different types of continuous-flow LVADs and device characteristics, including pump speeds, are listed in Table 1. The rotating impeller within the pump generates either axial flow (blood flow parallel to the impeller axis) or centrifugal flow (blood flow at a right angle to the impeller axis) from the left ventricular (LV) apex, through the device, to the ascending aorta. The HeartMate II (HM II; Thoratec Corp, Pleasanton, CA) is the only continuous-flow pump approved by the US Food and Drug Administration to act as a bridge to cardiac transplantation and as destination therapy. Operating speeds for this device are between 6000 and 15 000 revolutions per minute (rpm), which clinically translates …

Functional and haemodynamic recovery after implantation of continuous‐flow left ventricular assist devices in comparison with pulsatile left ventricular assist devices in patients with end‐stage heart failure

Caused by ageing of the population, better survival from ischaemic heart disease, and improved treatment of chronic heart disease, the incidence of heart failure has increased enormously. Worldwide, left ventricular assist devices (LVADs) are increasingly being used as a bridge or alternative to heart transplantation. In this study, we investigated whether there is difference in functional and haemodynamic recovery after implantation of pulsatile and continuous-flow pumps. We compared laboratory and echocardiographic data and exercise performance in patients with end-stage heart failure, before and 3 months after implantation of pulsatile and continuous-flow LVADs. A significant improvement in all laboratory parameters after implantation of both types of LVADs was seen, as well as a significant decrease in heart rate and LV dimensions, indicating better haemodynamics and cardiac recompensation. This improvement was better for the pulsatile device, probably due to higher plasma levels and higher LV dimensions before implantation. Exercise capacity strongly improved: 3 months after implantation of pulsatile and continuous-flow LVADs, peak VO(2) was 20.2 ± 4.8 vs. 18.3 ± 4.8 mL/kg/min (P = 0.09) (53 ± 12 vs. 49 ± 11% of predicted for age and gender) (P = 0.28). Pulsatile and continuous-flow LVADs result in extensive haemodynamic recovery and exercise performance compatible with daily life activities. Exercise performance with continuous-flow LVADs is equal to that with pulsatile devices. This, in combination with improved survival of the newer devices, allows its use as an alternative to heart transplantation in selected patients.

Neurocognitive function in destination therapy patients receiving continuous-flow vs pulsatile-flow left ventricular assist device support

The HeartMate II (Thoratec Corp, Pleasanton, CA) continuous-flow left ventricular assist device (LVAD) improved survival in destination therapy (DT) patients during a randomized trial compared with pulsatile-flow LVADs. This study documented changes in cognitive performance in DT patients from that trial to determine if there were differences between continuous-flow and pulsatile-flow support. Data were collected in a sub-study from 96 HeartMate II continuous-flow and 30 HeartMate XVE pulsatile-flow LVAD patients from 12 of the 35 trial sites that followed the same serial neurocognitive (NC) testing protocol at 1, 3, 6, 12, and 24 months after LVAD implantation. Spatial perception, memory, language, executive functions, and processing speed were the domains assessed with 10 standard cognitive measures. Differences over time and between LVAD type were evaluated with linear mixed-effects modeling. From 1 to 24 months after LVAD implantation, changes in NC functions were stable or showed improvement in all domains, and there were no differences between the continuous-flow and pulsatile-flow groups. Data at 24 months were only available from patients with the continuous-flow LVAD due to the limited durability of the HeartMate XVE device. There was no decline in any NC domain over the time of LVAD support. Missing data not collected from patients who died could have resulted in a bias toward inflated study results. The NC performance of advanced heart failure patients supported with continuous-flow and pulsatile-flow LVADs shows stabilization or improvement during support for up to 24 months.

Comparison of the effects of continuous and pulsatile left ventricular-assist devices on ventricular unloading using a cardiac electromechanics model

Left ventricular-assist devices (LVADs) are used to supply blood to the body of patients with heart failure. Pressure unloading is greater for counter-pulsating LVADs than for continuous LVADs. However, several clinical trials have demonstrated that myocardial recovery is similar for both types of LVAD. This study examined the contractile energy consumption of the myocardium with continuous and counter-pulsating LVAD support to ascertain the effect of the different LVADs on myocardial recovery. We used a three-dimensional electromechanical model of canine ventricles, with models of the circulatory system and an LVAD. We compared the left ventricular peak pressure (LVPP) and contractile ATP consumption between pulsatile and continuous LVADs. With the continuous and counter-pulsating LVAD, the LVPP decreased to 46 and 10%, respectively, and contractile ATP consumption decreased to 60 and 50%. The small difference between the contractile ATP consumption of these two types of LVAD may explain the comparable effects of the two types on myocardial recovery.

Results of the Post-U.S. Food and Drug Administration-Approval Study With a Continuous Flow Left Ventricular Assist Device as a Bridge to Heart Transplantation: A Prospective Study Using the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support)

The aim of this study was to determine whether results with the HeartMate (HM) II left ventricular assist device (LVAD) (Thoratec Corporation, Pleasanton, California) in a commercial setting are comparable to other available devices for the same indication. After a multicenter pivotal clinical trial conducted from 2005 to 2008, the U.S. Food and Drug Administration approved the HM II LVAD for bridge to transplantation (BTT). A post-approval study was required by the U.S. Food and Drug Administration to determine whether results with the device in a commercial setting are comparable to other available devices for the same indication. The study was a prospective evaluation of the first 169 consecutive HM II patients enrolled in the national INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) who were listed for transplant or likely to be listed. Patients were enrolled from April through August 2008 at 77 U.S. centers and followed for at least 1 year after implant. A comparison group (COMP) included all patients (n = 169 at 27 centers) enrolled in the INTERMACS registry with other types of LVADs (79% HeartMate XVE, 21% Implantable Ventricular Assist Device [Thoratec Corporation]) for the same BTT indication in the same time period. Survival rates, adverse events, and quality of life with the EuroQol EQ-5D visual analog scale were obtained in the INTERMACS registry. Baseline characteristics were similar, but creatinine and blood urea nitrogen were lower in the HM II versus COMP groups, and there were fewer patients in the highest-risk INTERMACS patient profile Number 1 (24% for HM II vs. 39% for COMP). Adverse event rates were similar or lower for HM II versus COMP for all events. Bleeding was the most frequent adverse event for both groups (1.44 vs. 1.79 events/patient-year). Operative 30-day mortality for HM II was 4% versus 11% for COMP. The percentage of patients reaching transplant, cardiac recovery, or ongoing LVAD support by 6 months was 91% for HM II and 80% for COMP, and the Kaplan-Meier survival for patients remaining on support at 1 year was 85% for HM II versus 70% for COMP. Quality of life was significantly improved at 3 months of support and sustained through 12 months in both groups compared with baseline. The results in a post-market approval, actual patient care setting BTT population support the original findings from the pivotal clinical trial regarding the efficacy and risk profile of the HM II LVAD. These data suggest that dissemination of this technology after approval has been associated with continued excellent results.

Changing outcomes in patients bridged to heart transplantation with continuous- versus pulsatile-flow ventricular assist devices: An analysis of the registry of the International Society for Heart and Lung Transplantation

Patients bridged to heart transplantation with left ventricular assist devices (LVADs) have been reported to have higher post-transplant mortality compared with those without LVADs. Our aim was to determine the impact of the type of LVAD and implant era on post-transplant survival. In this study we included 8,557 patients from the registry of the International Society for Heart and Lung Transplantation. We examined post-transplant outcomes in 1,100 patients bridged to transplant with pulsatile-flow LVADs between January 2000 and June 2004 (first era), 880 patients bridged with pulsatile-flow LVADs between July 2004 and May 2008 (second era), and 417 patients bridged with continuous-flow LVADs in the second era. Patients who required intravenous inotropes but not LVAD support (n = 2,728) and patients who did not require either LVAD or inotropes (n = 3,432) served as controls. Post-transplant survival of patients bridged with pulsatile LVADs improved significantly between the first and the second era (p = 0.03). In the second era, there was no significant difference in post-transplant survival of patients bridged with pulsatile- vs continuous-flow LVADs (p = 0.26), and survival rates in the 2 groups were not statistically different from that of the non-LVAD group. Graft rejection was similar in patients bridged with LVADs compared to those without LVADs. In the most recent era, the use of either pulsatile- or continuous-flow LVADs did not result in increased post-transplant mortality. This finding is important as the proportion of patients with LVADs at the time of transplant has been rising.

Reverse Remodeling With Left Ventricular Assist Devices

Over the last 2 decades, numerous advancements in medical therapies have improved patient outcomes in heart failure (HF). However, a significant number of patients still progress to end-stage HF, in which treatment options are largely limited to cardiac transplantation. As patient demands for transplant continue to exceed the supply of available organs, mechanical assist devices—specifically, the left ventricular assist device (LVAD)—were initially introduced as a bridge to cardiac transplantation. LVADs have 2 important beneficial effects. First, LVADs are placed in parallel to the native left ventricle (LV), causing pressure and volume unloading of the LV. Second, LVADs restore cardiac output and subsequent perfusion to the organs. As a result of these 2 effects, it became evident that some patients had actual improvement in LV function after LVAD placement. The term reverse remodeling was used to describe the improvement in myocardial function that was observed in patients with a seemingly end-stage disease. With reverse remodeling, a new hope for the treatment of HF was born—using LVADs as a bridge to recovery; however, to date, this promise has largely been unrealized. This probably is reflective of the fact that the sequela of mechanical ventricular unloading are quite complex and appear to involve the engagement of competing biological pathways including regression of cardiomyocyte hypertrophy as well as progressive cell atrophy. Although the promise of ventricular recovery still persists, its actualization will await a more comprehensive dissection of these competing biological processes. This review will discuss the beneficial clinical effects of LVAD support as well as review what is known about the cellular and molecular response to mechanical unloading and mechanisms of reverse remodeling. Key research findings have been summarized in the Table. View this table: Table. Summary of Research of LVAD Support on Clinical Effects and the Cellular and Molecular Changes That May Contribute to Reverse …

Less Frequent Opening of the Aortic Valve and a Continuous Flow Pump Are Risk Factors for Postoperative Onset of Aortic Insufficiency in Patients With a Left Ventricular Assist Device

Postoperative development of aortic insufficiency (AI) after implantation of left ventricular assist devices (LVADs) has recently been recognized, but the devices in the previous reports have been limited to the HeartMate I or II. The purposes of this study were to determine whether AI develops with other types of LVADs and to elucidate the factors associated with the development of AI. Thirty-seven patients receiving LVADs without evident abnormalities in native aortic valves were enrolled (pulsatile flow LVAD [TOYOBO]: 76%, continuous flow LVAD [EVAHEART, DuraHeart, Jarvik2000, HeartMate II]: 24%). Frequency of aortic valve opening and grade of AI were evaluated by the most recent echocardiography during LVAD support. None of the patients had more than trace AI preoperatively. During LVAD support AI >- grade 2 developed in 9 patients (24%) across all 5 types of devices. More severe grade of AI correlated with higher plasma B-type natriuretic peptide concentration (r = 0.53, P < 0.01) and with less frequent of the aortic valve (r = 0.45, P < 0.01). Multivariate analysis revealed that lower preoperative left ventricular ejection fraction and a continuous flow device type were independent risk factors for higher incidence of AI. AI, which is hemodynamically significant, develops after implantation of various types of LVADs. Physicians need to be more alert to the development of AI particularly with continuous flow devices.

Current Trends in Implantable Left Ventricular Assist Devices

The shortage of appropriate donor organs and the expanding pool of patients waiting for heart transplantation have led to growing interest in alternative strategies, particularly in mechanical circulatory support. Improved results and the increased applicability and durability with left ventricular assist devices (LVADs) have enhanced this treatment option available for end-stage heart failure patients. Moreover, outcome with newer pumps have evolved to destination therapy for such patients. Currently, results using nonpulsatile continuous flow pumps document the evolution in outcomes following destination therapy achieved subsequent to the landmark Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure Trial (REMATCH), as well as the outcome of pulsatile designed second-generation LVADs. This review describes the currently available types of LVADs, their clinical use and outcomes, and focuses on the patient selection process.

Outcomes of midterm circulatory support by left ventricular assist device implantation with descending aortic anastomosis

For some patients undergoing left ventricular assist device (LVAD) implantation, the perfusion tube is anastomosed to the descending aorta instead of the currently more prevalently used ascending aorta. Purpose of this study was to assess retrospectively the outcomes of LVAD patients with descending aortic anastomosis. Between March 2007 and March 2010, six patients underwent LVAD implantation with descending aortic anastomosis with Toyobo or Jarvik 2000 LVAD at our institute. Their average circulatory support time was 434(range 82-751)days. Both types of LVAD afforded adequate circulatory support, and inotrope treatment and mechanical ventilation were discontinued relatively early. Echocardiograms of the three patients with Jarvik 2000 LVAD revealed antegrade flow in the ascending aorta during the intermittent low-speed period. Among them, one patient developed infarction in the right brain hemisphere because of thromboembolism, whereas another patient developed pneumonia in the left lung followed by a lethal systemic infection. One patient on Toyobo LVAD support reached heart transplantation without morbidity. Another patient implanted with Toyobo LVAD, whose left ventricular function was too poor to generate forward flow through aortic valve, developed thrombus in the ascending aorta. No embolic events were observed in the organs below the diaphragm. In conclusion, descending aortic anastomosis of the perfusion tube can be used for LVAD implantation for some patients, but considerable risks of morbidities, including thromboembolic events and/or infection, should be recognized.

Prior Human Leukocyte Antigen-Allosensitization and Left Ventricular Assist Device Type Affect Degree of Post-implantation Human Leukocyte Antigen-Allosensitization

Left ventricular assist device (LVAD) implantation before heart transplantation has been associated with formation of antibodies directed against human leukocyte antigens (HLA), often referred to as sensitization. This study investigated whether prior sensitization or LVAD type affected the degree of post-implantation sensitization. The records of consecutive HeartMate (HM) I and HM II LVAD patients were reviewed. Panel reactive antibody (PRA) was assessed before LVAD implantation and biweekly thereafter. Sensitization was defined as PRA > 10%, and high-degree sensitization was defined as PRA > 90%. An HM LVAD was implanted in 64 patients, and 11 received a HM II LVAD as a bridge to transplant. Ten HM I patients (16%) were sensitized before LVAD implantation (HM I-S), and 54 (84%) were not (HM I-Non-S). Nine HM I-S patients (90%) became highly sensitized (PRA > 90%) compared with 9 HM I-Non-S patients (16.7%; p < 0.001). The PRA remained elevated (> 90%) in 8 of the 9 (88.9%) highly sensitized HM I-S patients vs 5 of the 9 (55.6%) HM I-Non-S highly sensitized patients. The PRA levels in the rest of the HM I-S highly sensitized patients declined from 93% +/- 4% to 55% +/- 15% (p = 0.01). Among the 11 HM II patients, 1 (9%) was sensitized before LVAD implantation (PRA, 40%) and the PRA moderately increased to 80%. No other HM II patient became sensitized after implantation. Thus, 1 of 11 (9%) HM II patients became sensitized compared with 29 of 64 (45%) HM I patients (p = 0.04). Pre-sensitized patients are at higher risk for becoming and remaining highly HLA-allosensitized after LVAD implantation. The HeartMate II LVAD appears to cause less sensitization than HeartMate I.

MEDICAL MANAGEMENT AFTER DISCHARGE IN LVADS WITH CONTINUOUS VERSUS PULSATILE FLOW: DIFFERENT DRUGS FOR DIFFERENT PUMPS?

Continuous and pulsatile left ventricular assist devices (LVAD) provide different signals that could lead to altered neurohormonal response. We hypothesized that this change in response may lead to different medical management post implant. Methods. Patients who had 3 months follow-up after LVAD implant were included. In 18 patients with continuous flow LVAD implantation (C group) and 33 patients with pulsatile LVAD (P group) data for mean blood pressure (MBP), creatinine, diuretics and antihypertensive drugs were collected at 1, 3, 6 and 12 months. Results. Average duration of LVAD support was similar between the two groups 372±276 days in C group vs. 344±246 days in P group, P=0.725. Serum creatinine levels (mg/dL) and MBP (mmHg) are listed in the table. Significantly more patients in C group were on diuretics at 1 month (14/18 vs. 12/33 patients, P=0.005) and 3 months (14/15 vs. 15/33 patients, P=0.002). At 6 months, significantly more patients in P group were on antihypertensive medications, 29/31 vs. 7/12 patients in C group, P=0.012.TableConclusion. These data indicate a temporary difference in medication needs related to the type of LVAD used. At one year, there is adjustment leading to disappearance of this difference.

Peripheral Vascular Reactivity in Patients With Pulsatile vs Axial Flow Left Ventricular Assist Device Support

Left ventricular assist devices (LVADs) are either pulsatile or axial flow devices. The latter can be operated at a low-speed setting to allow pulsatility or at a high-speed setting to create continuous flow. The purpose of this study was to compare the effect of continuous flow and pulsatile flow on peripheral vascular reactivity. Twenty consecutive patients were divided into two groups based on the type of LVAD they received. Ten patients had a pulsatile flow LVAD, and 10 had an axial flow LVAD. For the purpose of the study protocol, the axial flow devices were operated at a high speed to ensure continuous flow. The patients' peripheral artery vasoreactivity was assessed with an ultrasound vascular transducer that measured flow-mediated dilation (FMD). The FMD of the patients supported with pulsatile flow (15.6 +/- 5%) was higher than the FMD of the patients supported with temporary continuous flow (1.8 +/- 3%). The difference was statistically significant (p < 0.0001). Pulsatile flow is associated with a better peripheral vascular reactivity than continuous flow. Patients supported by axial flow devices should be kept on the lowest speed setting to allow maximum pulsatility.

228: Effects of left ventricular assist devices with different flow characteristics on vasopressin levels

Neurohormonal systems are activated by low cardiac output and arterial pressure. This can accelerate the progression of heart failure with increased morbidity and mortality. Vasopressin regulates vascular tone and free-water reabsorption. Limited data exists on effects of left ventricular assist devices (LVADs) on vasoactive peptides, specifically in regard to continuous vs. pulsatile type of LVADs. We tested the hypothesis that the continuous LVADs will improve the levels of these substances and in a shorter time frame than previous LVADs.