LVAD Pump Research Articles

Modification of Sleep Disordered Breathing after Increase in LVAD Pump Speed in HF Patients

Modification of Sleep Disordered Breathing after Increase in LVAD Pump Speed in HF Patients

LVAD Pump Speed Increase is Associated with Improvement of Cardiac Output, O2 Kinetic and O2 Muscle Extraction

LVAD Pump Speed Increase is Associated with Improvement of Cardiac Output, O2 Kinetic and O2 Muscle Extraction

Surgical Technique for Redo-Sternotomy Sparing Heartware HVAD Exchanges

Prolonged support times in bridge to transplant patients, as well as the growing number of destination patients lead to increased rates of LVAD pump exchanges for pump thrombosis, pump infections, and other device problems. We describe our surgical approach for pump exchanges in patients supported with the Heartware HVAD ventricular assist device. Pump exchanges are performed via a limited thoracotomy in the fourth, fifth, or sixth left intercostal space with cardiopulmonary bypass support. The apical sewing ring as well as the outflow graft are reused in order to limit the complexity of the procedure and minimize the need for extensive dissections. Given the significant reduction in surgical complexity and invasiveness, the described technique should be considered the standard approach for Heartware HVAD patients with device complications necessitating isolated pump exchanges.

Axial to Centrifugal Continuous Flow LVAD Pump Exchange Using Minimally Invasive Technique

Axial to Centrifugal Continuous Flow LVAD Pump Exchange Using Minimally Invasive Technique

(634) - Pump Thrombosis in Japanese Patients with HeartMate II Continuous-Flow LVAD Pump Thrombosis in Japanese Patients with HeartMate II Continuous-Flow LVAD

(634) - Pump Thrombosis in Japanese Patients with HeartMate II Continuous-Flow LVAD Pump Thrombosis in Japanese Patients with HeartMate II Continuous-Flow LVAD

Left ventricular assist pump pocket infection: conservative treatment strategy for destination therapy candidates.

Heart failure is a major cause of mortality and morbidity, particularly among patients with advanced disease and no access to cardiac transplantation. LVAD implantation is not only a bridge-to-transplantation option for patients awaiting a heart donor, but is often used as bridge-to-destination therapy in patients unsuited for transplantation for various reasons. LVAD infection is considered the second-most common cause of death in patients who survive the initial 6 months on LVAD support. Few reports describe the indications for chronic suppressing antibiotic therapy, device exchange, methods for exchanging infected devices, post-exchange antimicrobial management status, and the outcomes of such patients. This is the case of a 74-year-old male patient with numerous comorbidities who received urgent surgical management for severe heart failure with a HeartMate II. Six months later he developed an LVAD pump infection with methicillin-resistant Staphylococcus epidermidis, which was diagnosed with leucocyte scintigraphy. The patient received an omental graft over the LVAD and a chronic suppressive antibiotic regime. A marked leukocyte scintigraphy showed the infection's regression 6 months after the initiation of antibiotic treatment. We concisely reviewed the driveline infections and the main aspects of the LVAD pump infection. We reviewed options for conservative and nonconservative management and showed that conservative management of the LVAD pump infection is possible. There are no defined recommendations for the management of LVAD pump infection. This case is among the few in the literature showing that conservative treatment of an LVAD pump infection is possible.

Lvad pump speed increase is associated with increased peak exercise cardiac output and vo2, postponed anaerobic threshold and improved ventilatory efficiency

BackgroundsPeak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca−Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO.We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. MethodsFifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation. All patients had severe HF as shown by clinical evaluation, laboratory tests, echocardiography, spirometry with alveolar-capillary diffusion, and maximal cardiopulmonary exercise testing (CPET). CPETs with non-invasive CO measurements at rest and peak exercise were done on 2days at LVAD pump speed set randomly at 2 and 4. ResultsIncreasing LVAD pump speed from 2 to 4 increased CO from 3.4±0.9 to 3.8±1.0L/min (ΔCO 0.4±0.6L/min, p=0.04) and from 5.3±1.3 to 5.9±1.4L/min (ΔCO 0.6±0.7L/min, p<0.01) at rest and peak exercise, respectively. Similarly, VO2 increased from 788±169 to 841±152mL/min (ΔVO2 52±76mL/min, p=0.01) and from 568±116 to 619±124mL/min (ΔVO2 69±96mL/min, p=0.02) at peak exercise and at anaerobic threshold, respectively. Δ(Ca−Cv)O2 did not change significantly, while ventilatory efficiency improved (VE/VCO2 slope from 39.9±5.4 to 34.9±8.3, ΔVE/VCO2 −5.0±6.4, p<0.01). ConclusionsIn HF, an increase in CO with a higher LVAD pump speed is associated with increased peak VO2, postponed anaerobic threshold, and improved ventilatory efficiency.

(656) - Microbubbles in Patients with LVADs: Echocardiographic Markers for LVAD Pump Thrombosis?

Echocardiographically visualized microbubbles have been described in a few case reports of patients with LVADs experiencing pump thrombosis (PT). It is hypothesized that microbubbles are formed in the setting of obstruction to flow due to the localized high velocity flow and high pressure gradient that are generated and, thus could reflect severity of PT. However, the incidence and prognostic significance of microbubbles in PT is unknown. We reviewed all patients implanted with an LVAD at our center from 1/2010 to 9/2015. All PT events >30 days post-implant were identified. All echocardiograms performed at the time of the PT event were reviewed for the presence of microbubbles. Characteristics of PT events with and without microbubbles were compared. During the study period, 278 patients received an LVAD. 32 (11.5%) patients experienced a total of 45 distinct PT events. Echocardiograms were available in 41 PT events (average of 2.5 ± 1.3 studies/event). Of these, microbubbles were identified on ≥1 echocardiogram in 11 (27%) PT events. Baseline characteristics did not differ between patients with and those without microbubbles (Table). Microbubbles were present in 32% of PT events in axial flow LVADs vs. 10% of centrifugal flow LVADs (P=0.17). At the time of event, there was no significant difference in LDH at presentation, peak LDH, peak plasma free hemoglobin, INR at event, pump power or pump speed between the two groups. PT events occurred farther from time of implant in patients with microbubbles (594±531 vs 333±305 days, P=0.06). There was no difference in the groups in need for pump exchange (P=0.70), transplant (P=0.20), or death (P=0.54). Microbubbles are seen in approximately 1/4 of PT events. The presence of microbubbles does not predict severity of PT, response to therapy, or need for pump exchange or transplant. Nonetheless, visualization of microbubbles should prompt clinical evaluation for PT.

(654) - The Use of Heparin in the Setting of Elevated LDH and Suspected LVAD Pump Thrombus; a Single Center Experience

(654) - The Use of Heparin in the Setting of Elevated LDH and Suspected LVAD Pump Thrombus; a Single Center Experience

(1051) - Performance of Continuous Flow Left Ventricular Assist Devices for the Smaller Size Patient Population

Since continuous flow left ventricular assist devices (CF-LVAD) became a standard care for end-stage heart failure patients, it is still a challenge to implant CF-LVAD for smaller size patients. We analyzed mid-term outcomes of these patients. CF-LVADs were implanted in 73 patients (15 female, 40±13 year-old, 51 dilated cardiomyopathy) for the purpose of bridge to heart transplantation (HTx) (BTT) and implanted devices were HeartMateII in 36, EVAHEART in 17, Jarvik2000 in 10, DuraHeart in 9 and HeartWare in 1.The average body surface are (BSA) was 1.65±0.19 m2 (1.22-2.07). These patients were divided into two groups, standard group (BSA>1.6m2, n=43) and small group (BSA≤1.6m2, n=30). Mid-term clinical outcomes and data collected from post-implant echocardiography and catheter examination (obtained from 63 patients) were compared between two groups. Optimal LVAD pump speed was set by clinical parameters including echocardiography. The average support period was 1.7±1.1 years (0.1-4.3). Post-implant catheter data showed no significant difference between two groups in cardiac index (2.9±0.6L/m2 in small group, 2.8±0.5L/m2 in standard group, p=0.27) and mean pulmonary pressure 14±4 mmHg, 16±6 mmHg, p=0.10). Echocardiography at 1 month showed left ventricular dimension was significantly reduced in both group and there were no significant difference between two groups (18±15%, 14±17%, p=0.29). There were no operative deaths and 4 late deaths due to cerebrovascular accident (CVA) in 3 and right heart failure in 1. One- and 2-year survival rate (censored by HTx and recovery) for overall patients were 97% and 95%, respectively, and there were no significant difference between two groups (Log-rank test, p=0.59). CVA were recorded in 24 patients and 1- and 2-year freedom from CVA were 68% and 62%, respectively, and there were no significant difference between two groups (p=0.49). Serial echocardiography showed that 1- and 2-year freedom from mild or greater aortic regurgitation were 84% and 63% and there were no significant difference between two groups (p=0.60). CF-LVAD provided excellent clinical outcomes for small size patients in terms of survival and hemodynamics. There were no significant difference between small size patients and standard size patients.

(188) - Single Center Experience with Medical Therapy for Management of LVAD Pump Thrombosis

(188) - Single Center Experience with Medical Therapy for Management of LVAD Pump Thrombosis

(700) - Left Ventricular Assist Device - Related Infection: Long-Term Treatment Efficacy with Pump Exchange

LVAD-related infections (major driveline (MDL) and pump pocket (PP)) remain an important source of morbidity and mortality despite aggressive medical treatment and local surgical therapies. Data on efficacy and timing of surgical intervention with pump exchange to eradicate LVAD-related infections are limited. We reviewed the outcomes of pump exchange for MDL and PP infections not adequately controlled with medical therapy. A retrospective review of patients who received durable LVAD pump exchange-for device related infection- at a single institution from August 2005 - June 2015. Clinical, radiologic, microbiology, medical and surgical treatment data were abstracted from medical records and the institutional VAD registry. PP infections were treated with device exchange with omental wrap of the new device. New or recurrence of infection following exchange was defined by LVAD-related infection within 12 months of pump exchange. The primary outcomes included freedom of recurrent or new infection after one year following pump exchange and overall survival. During the study period, 22 patients underwent durable LVAD exchange. Median age was 55 years, 16 (73%) were males, and 5(24%) were destination therapy. Median follow-up was 27 months (range 2 to 82). Fifteen patients (68%) were free of new or recurrent device-related infection at 1-year. Actuarial survival at 1-year was 95±5% following device exchange. The median time from first MDL or PP infection to pump exchange was shorter in patients with no recurrence compared to patients with recurrence (43 versus 195 days). The most common pathogens were Methicillin-sensitive Staphylococcus aureus (47%), Pseudomonas Aeruginosa (14%), Methicillin-resistant Staphylococcus aureus (10%) and Serratia Marcescenes (10 %). There was no correlation to recurrence and initial pathogen. Pump exchange for device-related infection provides a durable outcome for patients with device-elated infection not controlled with medical therapy. These data suggest that early pump exchange for MDL or PP infection may provide greater long-term freedom from recurrent infection.

(282) - Spontaneous Microbubble Formation Is an Indicator of LVAD Pump Thrombosis

(282) - Spontaneous Microbubble Formation Is an Indicator of LVAD Pump Thrombosis

(29) - Breaking Bad: Dissimulated Amphetamine Abuse as a Rare Cause of Recurrent LVAD Pump Thrombosis

(29) - Breaking Bad: Dissimulated Amphetamine Abuse as a Rare Cause of Recurrent LVAD Pump Thrombosis

Body Position and Activity, But Not Heart Rate, Affect Pump Flows in Patients With Continuous-Flow Left Ventricular Assist Devices

ObjectivesThe aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). BackgroundAlthough it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. MethodsTwo studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. ResultsHeart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. ConclusionsCentrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate.

Efficacy and durability of central oversewing for treatment of aortic insufficiency in patients with continuous-flow left ventricular assist devices

Aortic insufficiency (AI) in patients supported with continuous-flow left ventricular assist devices (CF-LVAD) results in regurgitant volume returning from the aorta to the left ventricle, increased LVAD pump volume and reduced systemic cardiac output. One common strategy to address AI during CF-LVAD support is central oversewing of the aortic valve, which allows some opening between the valve leaflets laterally. However, the long-term durability of this technique has not been extensively described. All patients who underwent central oversewing of the aortic valve during CF-LVAD support between January 2006 and March 2013 were included in this analysis. Pre- and post-procedure intra-operative transesophageal echocardiograms (TEEs) were reviewed to determine the efficacy of the surgical technique, whereas all subsequent transthoracic echocardiograms (TTEs) were reviewed to assess durability. AI severity was graded using the vena contracta (VC) width and the ratio between the VC and left ventricular outflow tract (LVOT) diameter. Nineteen patients with central aortic valve oversewing were identified. Median follow-up was 560 days (range 46 to 954 days). All but 1 patient had their aortic insufficiency reduced to "none/trace" on post-operative TEE. There was no statistically significant increase in the VC width and VC/LVOT ratio between the first and last follow-up echocardiograms, and only 2 patients developed more than mild aortic insufficiency after central oversewing. Central oversewing of the aortic valve did not adversely affect outcomes after LVAD implantation. Central oversewing of the aortic valve is an effective and durable means of addressing greater than mild AI in patients with CF-LVAD.

(525) - Efficacy and Durability of Central Oversewing for Treatment of Aortic Valve Insufficiency in Patients with Continuous Flow Left Ventricular Assist Devices

(525) - Efficacy and Durability of Central Oversewing for Treatment of Aortic Valve Insufficiency in Patients with Continuous Flow Left Ventricular Assist Devices

Lysis in patient with a pump thrombosis after implantation of a left ventricular assist device

Background: Left ventricular assist device implantation is an established therapy in patients with end-stage heart failure. Limitations in the durability of these pumps are the development of a pump thrombosis. A lysis therapy may avoid a surgical pump exchange. In a retrospective study we analyzed the efficacy of a lysis therapy in LVAD patients. Methods: A pump thrombosis was diagnosed to high power or flow, increased LDH levels (>500 U/L) and hematuria. Low dose of Actilyse were given if two of three criteria were fulfilled. Results: Between 4/12 and 8/2013, 30 lysis were done in 11 patients with different left ventricular assist device (HVAD, HeartMate II, Synergy). In 36% the lysis therapy was successful with normalization of LVAD parameter and LDH level. An exchange of the pump was necessary in 6 patients in spite of lysis therapy. Bleeding complications occurred in 13% after lysis therapy. One patient died due to intracerebral bleeding. Conclusion: Low dose lysis therapy has a low complications rate but has to be done in most of the patients several times. An exchange of the LVAD pump is a high risk surgical procedure but can be avoided by using lysis therapy only in one third of the patients with a pump thrombosis.

First Berlin Heart EXCOR Pediatric VAD Interhospital Transports of Nonambulatory Patients with the Ikus Stationary Driver

Ventricular assist devices (VADs) are increasingly being used in pediatric patients to support cardiac failure. As more centers adopt this technology, there may be a need to transport these patients over long distances to facilitate patient care and organ transplantation. Food and Drug Administration indications for use state only that the patient must be a candidate for transplantation and does not place restrictions on the transplant capabilities of the implanting medical center. Nontransplanting institutions are able to use this technology with a predetermined agreement to transfer the patient to a partnering transplant center. We report the first two cases of interhospital air and ground transport of nonambulatory or intubated pediatric (<13 kg) patients supported by Berlin Heart EXCOR pediatric VADs and Ikus stationary drivers. We present our protocol for transporting this delicate patient population. In addition, we discuss important challenges encountered on these operations regarding vehicle transfers and the management of vehicle power supply. These two cases demonstrate that the transportation of pediatric patients on Berlin Heart VADs is feasible and safe and should be considered a treatment option in certain situations.

A Novel and Simple Echocardiographic Tool To Detect Malfunction of Continuous-Flow Left Ventricular Assist Devices during Speed Change Testing: The LVAD Pump Thrombosis Score

Malfunction of Continuous Flow Left Ventricular Assist Devices (CF-LVAD), frequently due to device thrombosis, is a potentially life-threatening event that presents a diagnostic and time consuming challenge due to limitation of imaging techniques to visualize pump interior.