Left Ventricular Assist Devices Type Research Articles

Clinical outcomes and healthcare expenditures in the real world with left ventricular assist devices – The CLEAR-LVAD study

Several distinctly engineered left ventricular assist devices (LVADs) are in clinical use. However, contemporaneous real world comparisons have not been conducted, and clinical trials were not powered to evaluate differential survival outcomes across devices. Determine real world survival outcomes and healthcare expenditures for commercially available durable LVADs. Using a retrospective observational cohort design, Medicare claims files were linked to manufacturer device registration data to identify de-novo, durable LVAD implants performed between January 2014 and December 2018, with follow-up through December 2019. Survival outcomes were compared using a Cox proportional hazards model stratified by LVAD type and validated using propensity score matching. Healthcare resource utilization was analyzed across device types by using nonparametric bootstrap analysis methodology. Primary outcome was survival at 1-year and total Part A Medicare payments. A total of 4,195 de-novo LVAD implants were identified in fee-for-service Medicare beneficiaries (821 HeartMate 3; 1,840 HeartMate II; and 1,534 Other-VADs). The adjusted hazard ratio for mortality at 1-year (confirmed in a propensity score matched analysis) for the HeartMate 3 vs HeartMate II was 0.64 (95% CI; 0.52-0.79, p< 0.001) and for the HeartMate 3 vs Other-VADs was 0.51 (95% CI; 0.42-0.63, p < 0.001). The HeartMate 3 cohort experienced fewer hospitalizations per patient-year vs Other-VADs (respectively, 2.8 vs 3.2 EPPY hospitalizations, p < 0.01) and 6.1 fewer hospital days on average (respectively, 25.2 vs 31.3 days, p < 0.01). The difference in Medicare expenditures, conditional on survival, for HeartMate 3 vs HeartMate II was -$10,722, p < 0.001 (17.4% reduction) and for HeartMate 3 vs Other-VADs was -$17,947, p < 0.001 (26.1% reduction). In this analysis of a large, real world, United States. administrative dataset of durable LVADs, we observed that the HeartMate 3 had superior survival, reduced healthcare resource use, and lower healthcare expenditure compared to other contemporary commercially available LVADs.

Left Ventricular Assist Device Flow Pattern Analysis Using a Novel Model Incorporating Left Ventricular Pulsatility.

Our current understanding of flow through the circuit of left ventricular assist device (LVAD), left ventricle and ascending aorta remains incompletely understood. Computational fluid dynamics, which allow for analysis of flow in the cardiovascular system, have been used for this purpose, although current simulation models have failed to fully incorporate the interplay between the pulsatile left ventricle and continuous-flow generated by the LVAD. Flow-through the LVAD is dependent on the interaction between device and patient-specific factors with suboptimal flow patterns evoking increased risk of LVAD-related complications. Computational fluid dynamics can be used to analyze how different pump and patient factors affect flow patterns in the left ventricle and the aorta. Computational fluid dynamics simulations were carried out on a patient with a HeartMate II. Simulations were also conducted for theoretical scenarios substituting HeartWare HVAD, HeartMate 3 (HM3) in continuous mode and HM3 with Artificial Pulse. An anatomical model of the patient was reconstructed from computed tomography (CT) images, and the LVAD outflow was used as the inflow boundary condition. The LVAD outflow was calculated separately using a lumped-parameter-model of the systemic circulation, which was calibrated to the patient based on the patient-specific ventricular volume change reconstructed from 4 dimensional computed tomography and pulmonary capillary wedge pressure tracings. The LVADs were implemented in the lumped-parameter-model via published pressure head versus flow (H-Q) curves. To quantify the flushing effect, virtual contrast agent was released in the ascending aorta and its flushing over the cycles was quantified. Shear stress acting on the aortic endothelium and shear rate in the bloodstream were also quantified as indicators of normal/abnormal blood flow, especially the latter being a biomarker of platelet activation and hemolysis. LVAD speeds for the HVAD and HM3 were selected to match flow rates for the patient's HMII (9,000 RPM for HMII, 5,500 RPM for HM3, and 2,200 RPM for HVAD), the cardiac outputs were 5.81 L/min, 5.83 L/min, and 5.92 L/min, respectively. The velocity of blood flow in the outflow cannula was higher in the HVAD than in the two HeartMate pumps with a cycle average (range) of 0.92 m/s (0.78-1.19 m/s), 0.91 m/s (0.86-1.00 m/s), and 1.74 m/s (1.40-2.24 m/s) for HMII, HM3, and HVAD, respectively. Artificial pulse increased the peak flow rate to 9.84 L/min for the HM3 but the overall cardiac output was 5.96 L/min, which was similar to the continuous mode. Artificial pulse markedly decreased blood stagnation in the ascending aorta; after six cardiac cycles, 48% of the blood was flushed out from the ascending aorta under the continuous operation mode while 60% was flushed under artificial pulse. Shear stress and shear rate in the aortic arch were higher with the HVAD compared to the HMII and HM3, respectively (shear stress: 1.76 vs. 1.33 vs. 1.33 Pa, shear rate: 136 vs. 91.5 vs. 89.4 s-1). Pump-specific factors such as LVAD type and programmed flow algorithms lead to unique flow patterns which influence blood stagnation, shear stress, and platelet activation. The pump-patient interaction can be studied using a novel computational fluid dynamics model to better understand and potentially mitigate the risk of downstream LVAD complications.

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.

Finding a proper "Mate": Comparison of left ventricular assist devices using cerebral oximetry.

Axial-flow and centrifugal-flow left ventricular assist devices (LVAD) have been utilized in the management of heart failure, but it remains unknown whether these devices differ in end-organ perfusion. Our goal was to evaluate the association between device type and regional cerebral oxygen saturation (rSO2), and determine if this confers any benefit in short-term postoperative outcomes. Adult patients who underwent primary LVAD implantation at our institution from 2014 to 2019 were retrospectively analyzed. Patients were stratified into axial-flow and centrifugal-flow groups. Intraoperative rSO2 readings were used to calculate the change in mean rSO2 from pre- to post-bypass. Multivariable modeling was performed to compare delta rSO2 between groups, and to analyze the association between LVAD type and postoperative outcomes. There were 152 patients included, of which 76 had an axial-flow device and 76 had a centrifugal-flow device implanted. The rSO2 level increased from pre-bypass to post-bypass on average 3.5% (CI: 2.1 to 5.0) for the axial group compared to 0.1% (CI: -1.2 to 1.4) for the centrifugal group, which was a significant difference (β = -2.22, CI: -4.21 to -0.32, p = 0.022). Axial devices approached significance for lower odds of postoperative complications (OR: 0.35, CI: 0.11 to 1.06, p = 0.063), and were associated with significantly shorter ICU LOS (β = -0.36, CI: -0.60 to -0.11, p = 0.004). Axial devices resulted in a greater increase in rSO2 than centrifugal pumps after separation from CPB. Further investigation is warranted to evaluate the effect of LVAD selection on long-term end-organ perfusion and subsequent patient outcomes.

Efficacy And Safety of Low-dose Intravenous Vitamin K For International Normalized Ratio Reversal In Left Ventricular Assist Device Patients

Introduction Left ventricular assist device (LVAD) patients require warfarin, a vitamin K antagonist, as an anticoagulant to prevent thromboembolic events. LVAD patients that present with bleeding requiring a non-emergent procedure (ie. endoscopy) often require an international normalized ratio (INR) Hypothesis Low-dose IV vitamin K ( Methods We conducted a single-center, retrospective cohort analysis comparing low-dose IV vitamin K to “watchful waiting” in 100 LVAD patients. Baseline characteristics such as LVAD type, baseline INR (median and IQR), and vitamin K dose were collected. Primary endpoints included thrombotic and bleeding events within 90 days of discharge and number of patients with INR Results Patients in the IV vitamin K group had no thrombotic events compared to 23% of patients in the “watchful waiting” group (p=0.085). There were 38.5% and 11.8% bleeding event rates in the Vitamin K and “watchful waiting” groups, respectively (p=0.091). Patients receiving Vitamin K were more likely to have an INR Conclusion Using IV vitamin K to reverse warfarin prior to a non-emergent procedure was as safe as and more efficacious than “watchful waiting” alone. The major limitation of this study is its retrospective, non-randomized nature. Future prospective evaluation with a randomized controlled trial will be needed to corroborate these findings.

Location of the Cannula of the Left Ventricular Assist Device in Explanted Hearts After Orthotopic Heart Transplantation

Many patients having orthotopic heart transplantation (OHT) have previously had a left ventricular assist device (LVAD). Such a scenario allows the study of the position of the LVAD cannula in the explanted heart. We studied the explanted hearts in 105 patients who had had a LVAD inserted earlier and later underwent OHT at Baylor University Medical Center from January 2005 to September 2019, and compared the patients in whom the margins of the LVAD cannula contacted the mural endocardium with those in whom it did not. The margins of the orifice of the LVAD cannula contacted the left ventricular (LV) mural endocardium in 38 (36%) patients (considered potentially hazardous insertion) whereas in 67 (64%) patients there was no contact (considered "ideal" insertion). Comparison of the patients with ideal cannular insertion to those with potentially hazardous insertion disclosed insignificant differences in age at LVAD insertion or OHT; gender; interval between the LVAD insertion and OHT; body mass index; underlying cardiac disease; whether or not the heart floated in a container of formaldehyde, and the type of LVAD inserted. The margins of the LVAD cannula contacted the LV mural endocardium significantly more in patients with smaller mean heart weights than those with larger mean heart weights. In conclusion, of the 105 patients studied, the cannula of the LVAD resided in the LV cavity at an angle that allowed the margins of the orifice of the cannula to contact the mural endocardium in 38 (36%), a situation that at least potentially could cause partial obstruction of its orifice. Nevertheless, comparison of the 38 patients with nonideal cannular insertion to the 67 with ideal cannular insertion disclosed only 1 significant difference between the 2 groups.

Reactivation of Cytomegalovirus Following Left Ventricular Assist Device Implantation: A Case–Control Study

While cytomegalovirus (CMV) reactivation occurs in immunocompetent patients who are critically ill and has been associated with worse outcomes, very few cases of CMV reactivation have been reported following left ventricular assist device (LVAD) implantation. We aimed to evaluate the incidence and risk factors for CMV reactivation following LVAD implantation. Retrospective chart review of patients who had undergone LVAD implantation between July 2004 and December 2018 was performed. Cases with CMV reactivation post-LVAD were randomly matched (1:2) by sex, LVAD type, and implant year with controls utilizing SAS macros. Fisher's exact and paired sample t-tests were performed to evaluate for differences between categorical and continuous variables, respectively. Days to reactivation post-LVAD implantation were calculated in cases, and the corresponding times post-LVAD implantation were determined in control patients for variable comparisons. Survival analysis was performed using the Kaplan-Meier method. Of the 349 patients reviewed, 208 (59.6%) patients were seropositive for CMV before LVAD implantation. Of these 208 patients, eight (3.8%) had CMV reactivation following LVAD implantation. The median time to CMV reactivation following LVAD implantation was 21.5 days (range, 6-177). Six (75%) patients had CMV viremia, and the other two had colitis and pneumonia without viremia. In comparison to controls, patients with CMV had higher creatinine levels (p = 0.039) and higher RDW (p = 0.05) and were more likely to have received steroids within the previous week (p = 0.028) and to have concurrent bacterial infection (p = 0.001). CMV reactivation following LVAD implantation is more frequent than expected. Early testing, diagnosis, and treatment in at-risk patients (i.e., renal failure, steroid use, elevated RDW) might improve clinical outcomes.

Implantable cardioverter-defibrillator lead revision following left ventricular assist device implantation.

Lead dysfunction can lead to serious consequences including failure to treat ventricular tachycardia or fibrillation (VT/VF). The incidence and mechanisms of lead dysfunction following left ventricular assist device (LVAD) implantation are not well-described. We sought to determine the incidence, mechanisms, timing, and complications of right ventricular lead dysfunction requiring revision following LVAD implantation. Retrospective observational chart review of all LVAD recipients with pre-existing implantable cardioverter-defibrillator (ICD) from 2009 to 2018 was performed including device interrogation reports, laboratory and imaging data, procedural reports, and clinical outcomes. Among 583 patients with an ICD in situ undergoing LVAD implant, the median (interquartile range) age was 62.5 (15.7) years, 21% were female, and the types of LVADs included HeartWare HVAD (26%), HeartMate II (52%), and HeartMate III (22%). Right ventricular lead revision was performed in 38 patients (6.5%) at a median (25th, 75th) of 16.4 (3.6, 29.2) months following LVAD. Mechanisms of lead dysfunction included macrodislodgement (n = 4), surgical lead injury (n = 4), recall (n = 3), insulation failure (n = 8) or conductor fracture (n = 7), and alterations in the lead-myocardial interface (n = 12). Undersensing requiring revision occurred in 22 (58%) cases. Clinical sequelae of undersensing included failure to detect VT/VF (n = 4) and pacing-induced torsade de pointes (n = 1). Oversensing occurred in 12 (32%) and sequelae included inappropriate antitachycardia pacing ([ATP], n = 8), inappropriate ICD shock (n = 6), and ATP-induced VT (n = 1). The incidence of right ventricular lead dysfunction following LVAD implantation is significant and has important clinical sequelae. Physicians should remain vigilant for lead dysfunction after LVAD surgery and test lead function before discharge.

Neurologic Complications in Patients with Left Ventricular Assist Devices: Single Institution Retrospective Review

Neurologic complications are common complications encountered by patients with left ventricular assist devices (LVADs). This single-center retrospective study aims to identify the incidence and risk factors of neurologic complications and interventions in patients supported with LVADs and define the associated anticoagulation management. Between August 2009 and August 2017, 244 patients underwent LVAD implantation. Twenty-one patients were excluded for having neurologic complications before LVAD placement or for having previously undergone heart transplantation. Fifty-six patients (25%) suffered 61 complications, and 11 (19.6%) died as a result. Gender, type of LVAD, or chronic medical comorbidities evaluated did not contribute to a difference in complication rate; in contrast, length of LVAD implantation was directly related to risk of neurologic complication. Eleven patients (19.6%) underwent 13 surgical interventions including 5 mechanical thrombectomies. Anticoagulation was reversed in 16 patients and held without complication. Anticoagulation was not held for ischemic complications, and no clinically significant hemorrhagic transformation occurred. Intravenous tissue plasminogen activator was also successfully administered to 3 patients without complication. Neurologic complications were observed in 25% of patients supported with LVADs, of which 20% required neurosurgical intervention. Anticoagulation can be safely withheld in patients with hemorrhagic complications. Patients with ischemic complications can continue to be anticoagulated with no significant risk of hemorrhagic transformation. Length of LVAD implantation was directly related to the risk of neurologic complication. Finally, our study adds to existing literature that mechanical thrombectomy and even intravenous tissue plasminogen activator are options for LVAD patients with ischemic complications.

Successful Use of Sacubitril/Valsartan in Patients with a Left Ventricular Assist Device

The purpose of this study is to evaluate the safety and efficacy of angiotensin receptor-neprilysin inhibition with sacubitril/valsartan in patients supported with a left ventricular assist device (LVAD). This was a longitudinal, retrospective review evaluating LVAD patients managed by a single non-transplant center who have been prescribed sacubitril/valsartan. The primary objective was to evaluate the tolerability and efficacy of sacubitril/valsartan at 1 month and at last follow-up. Data points included baseline demographics, comorbidities, type of LVAD, time to initiation of sacubitril/valsartan, concomitant medications, change in mean arterial pressure (MAP), change in laboratory values, and reasons for discontinuation when applicable. Tolerability was defined as continued use without clinically significant adverse events. Efficacy was defined as improvement in MAP and overall clinical symptoms. Categorical data was analyzed with Mann-Whitney U or Chi-squared test, and t-tests are utilized for continuous data. Nine patients who were initiated on sacubitril/valsartan post-LVAD implantation were identified. The mean age was 52 years, and the majority of patients were African American (67%), male (67%), and received an LVAD for destination therapy (89%). All three commercially available LVADs were evenly represented. Over half of the patients (55%) were converted to sacubitril/valsartan from other renin-angiotensin-aldosterone system inhibitors. Only one patient received sacubitril/valsartan for heart failure management prior to LVAD implantation. Average MAP for all patients at baseline was 113 mmHg but decreased to 95 mmHg at last follow-up (p=0.032). There were no episodes of hyperkalemia. One episode of acute kidney injury was seen but was believed to be related to use of spironolactone. One patient discontinued therapy within the first month due to hypovolemia. At last follow-up, three patients reached the maximum sacubitril/valsartan dose of 97/103 mg twice daily. Sacubitril/valsartan was shown to significantly reduce blood pressure in LVAD patients. It was well tolerated in this patient population with only one patient discontinuing therapy. Further large, prospective evaluation is needed to confirm these results and determine overall role for sacubitril/valsartan in LVAD patients.

Acute Anticoagulation after Ischemic Stroke in Patients with Left Ventricular Assist Devices

Despite reductions in major adverse events with the latest generation of left ventricular assist devices (LVADs), the incidence of stroke remains high. The timing of anticoagulation resumption is controversial. We aim to explore practices of anticoagulation management following ischemic stroke in LVAD patients and identify optimal strategies. We retrospectively analyzed our LVAD database between 11/2012 and 5/2018. Patients who suffered ischemic stroke were categorized into 3 groups based on the timing of anticoagulation resumption post-stroke: anticoagulation immediately continued (A), held 1-4 days (B), held >4 days (C). Primary outcome events included recurrent ischemic stroke or TIA, pump thrombosis, systemic thrombosis, and intracranial or extracranial bleeding within 90 days. Descriptive and nonparametric survival analyses were performed. Of the 38 patients identified as having an ischemic stroke, 22 experienced 37 primary outcomes including 5 recurrent ischemic strokes/TIAs, 3 pump thromboses, 15 systemic embolic events, 9 intracranial and 5 systemic hemorrhages. We found no significant association between timing of anticoagulation resumption and incidence of subsequent ischemic events (Group A= 39%, B= 22%, C= 17%) or intracranial bleeding (Group A= 17%, B= 33%, C= 33%). Kaplan-Meier survival free of a primary outcome for all patients was 65%, 56% and 50% at 7, 14 and 30 days post ischemic stroke, respectively. There was no association between survival and timing of anticoagulation, sex, LVAD type or placement before vs after 2014. We found a high rate of early outcomes after ischemic stroke in LVAD patients, with no evidence of increased risk with continued anticoagulation. Accepting the limitations of a retrospective study, these data suggest that anticoagulation may not need to be held acutely to prevent hemorrhagic conversion. Risk factors for these post ischemic stroke outcomes however were not identified. Further research is needed to identify approaches to decrease these secondary complications.

Redefining Normal Outflow Cannula Velocity Reference Values for Each Left Ventricular Assist Device

2D transthoracic echocardiography (TTE) remains an integral component of imaging left ventricular assist devices (LVAD) and determining proper functionality of these devices. Despite relying heavily on transthoracic echocardiography, little is known about standardization of echocardiographic values and measurements pertinent to different types of devices (i.e. HeartMate II (HMII), Heartmate 3 (HM3), or HeartWare HVAD). We identified 216 patients with HM3, HM2, and HVAD left ventricular assist devices. For each patient, we identified all transthoracic echocardiograms that had been performed post-LVAD implantation (n=489 TTEs). Peak outflow cannula velocities were measured using continuous wave Doppler from the right sternal border position on the chest (most co-axial to flow). Patients with incomplete continuous Doppler waveforms were excluded. Peak velocities were different for all three LVADs. The mean peak velocity for the HMII (n=289) was 1.74±0.575 m/s, the mean peak velocity for the HM3 (n=113) was 1.54±0.458 m/s and the mean peak velocity for the HVAD (n=87) was 2.07±0.762 m/s. The mean peak velocity for the HeartMate 2 was significantly different than the HeartMate 3 (p=0.0013). Similarly, the HeartMate 2 velocity was also different than the HeartWare HVAD (p=0.000011). When the mean peak velocities of the HeartMate 3 were compared with the HeartWare HVAD, statistical significance was also found (p=0.0000000039). Mean peak outflow cannula velocities differ significantly in each of today's most commonly used LVADs. Different reference standards should be considered for each LVAD type.

Emerging electromagnetic interferences between implantable cardioverter-defibrillators and left ventricular assist devices.

AimsTo investigate the prevalence of electromagnetic interference (EMI) between left ventricular assist devices (LVADs) and implantable cardioverter-defibrillators (ICDs)/pacemakers (PMs).Methods and resultsA retrospective single-centre study was conducted, including all patients undergoing HeartMate II (HMII) and HeartMate 3 (HM3) LVAD implantation (n = 106). Electromagnetic interference was determined by the inability to interrogate the ICD/PM. Overall, 85 (mean age 59 ± 8, 79% male) patients had an ICD/PM at the time of LVAD implantation; 46 patients with HMII and 40 patients with HM3. Among the 85 LVAD patients with an ICD’s/PM’s, 11 patients (13%) experienced EMI; 6 patients (15%) with an HMII and 5 patients (11%) with an HM3 (P = 0.59). Electromagnetic interference from the HMII LVADs was only present in patients with a St Jude/Abbott device; 6 of the 23 St Jude/Abbott devices. However, in the HM3 patients, EMI was mainly present in patients with Biotronik devices: 4 of the 18 with only one (1/25) patient with a Medtronic device. While initial interrogation of these devices was not successful, none of the 11 cases experienced pacing inhibition or inappropriate shocks.ConclusionIn summary, the prevalence of EMI between ICDs in the older and newer type of LVAD's remains rather high. While HMII patients experienced EMI with a St Jude/Abbott device (which was already known), HM3 LVAD patients experience EMI mainly with Biotronik devices. Prospective follow-up, preferably in large registries, is warranted to investigate the overall prevalence and impact of EMI in LVAD patients.

Incidence and impact of acute kidney injury on patients with implantable left ventricular assist devices: a Meta-analysis

Background We aimed to evaluate the acute kidney injury (AKI) incidence and its associated risk of mortality in patients with implantable left ventricular assist devices (LVAD). Methods A systematic literature search in Ovid MEDLINE, EMBASE, and Cochrane Databases was conducted through January 2020 to identify studies that provided data on the AKI incidence and AKI-associated mortality risk in adult patients with implantable LVADs. Pooled effect estimates were examined using random-effects, generic inverse variance method of DerSimonian-Laird. Results Fifty-six cohort studies with 63,663 LVAD patients were enrolled in this meta-analysis. The pooled incidence of reported AKI was 24.9% (95%CI: 20.1%–30.4%) but rose to 36.9% (95%CI: 31.1%–43.1%) when applying the standard definition of AKI per RIFLE, AKIN, and KDIGO criteria. The pooled incidence of severe AKI requiring renal replacement therapy (RRT) was 12.6% (95%CI: 10.5%–15.0%). AKI incidence did not differ significantly between types of LVAD (p = .35) or indication for LVAD use (p = .62). While meta-regression analysis did not demonstrate a significant association between study year and overall AKI incidence (p = .55), the study year was negatively correlated with the incidence of severe AKI requiring RRT (slope = −0.068, p < .001). The pooled odds ratios (ORs) of mortality at 30 days and one year in AKI patients were 3.66 (95% CI, 2.00–6.70) and 2.22 (95% CI, 1.62–3.04), respectively. The pooled ORs of mortality at 30 days and one year in severe AKI patients requiring RRT were 7.52 (95% CI, 4.58–12.33) and 5.41 (95% CI, 3.63–8.06), respectively. Conclusion We found that more than one-third of LVAD patients develop AKI based on standard definitions, and 13% develop severe AKI requiring RRT. There has been a potential improvement in the incidence of severe AKI requiring RRT for LVAD patients. AKI in LVAD patients was associated with increased 30-day and 1 year mortality.

P820 Echocardiographic assessment of late-onset right ventricular dysfunction following continuous-flow left ventricular assist device

Abstract Early right ventricular failure (RVF) remains one of the main factors associated with early mortality following continuous-flow left ventricular assist device (LVAD) implantation. However, late-onset RVF (LoRVF) has emerged as an increasing concern, but little is known about its incidence rate and the value of transthoracic echocardiography (TTE) to predict this complication during the LVAD follow-up. Methods and results We retrospectively analyzed the 1-year hemodynamic and clinical data from patients (p) that, between 2016 and 2018, underwent a right heart catheterization (RHC) after LVAD as bridge to transplantation (BTT). 73 p (84% males, 52 ± 12 years, 49% Heart Ware LVAD, 51% Heart Mate 3 LVAD), out of 187 LVAD implants, were studied. According to the Intermacs definition, LoRVF was assigned if the RHC showed a central venous pressure (CVP)&amp;gt;18 mmHg with cardiac index&amp;lt; 2.3 L/min/m2. Isolated LoRVF was assigned if LoRVF was present in the absence of elevated pulmonary capillary wedge pressure (PCWP) ≤15 mmHg. TTE was performed at the time of the RHC and the following parameters were obtained: parasternal long-axis left ventricular end diastolic diameter (LVEDD), basal (RVED1) and mid-cavity (EDRV2) end diastolic RV linear dimension in 4 chamber view, severity of tricuspid regurgitation (TR) and of mitral regurgitation (MR), tricuspid annular plane systolic excursion (TAPSE), and the position of the LVAD inflow cannula (IC). LoRVF was present in 16 p (22% of the studied population): 12 p (75%) presented a PCWP &amp;gt; 15 mmHg and 4 p (25%) presented isolated LoRVF. Symptoms and signs of venous congestion were present in 2/3 of the p with LoRVF and elevated PCWP. On the other hand, all the p with isolated LoRVF presented severe signs of venous congestion, and 50% of them could be successfully transplanted in high urgent status. P with LoRVF showed more dilated RV (RVED1 43.8 ± 9.2 vs 37.7 ± 5.3 mm, p = 0.02) and lower TAPSE (11 ± 2 vs 14 ± 2 mm p &amp;lt; 0.01) than the no LoRVF group. RVED1 showed a weak significant correlation with CVP (R = 0.3, p = 0.02). On the other hand, the presence of an elevated PCWP was not related to etiology of the cardiomyopathy, type and speed of LVAD, position of the IC, LVEDD, nor the presence of MR &amp;gt; mild. Conclusion LoRVF is a frequent complication during LVAD support as BTT and most of the cases are associated with persistent elevated PCWP. Isolated LoRVF, which is not associated with high PCWP, has a bad prognosis. RV evaluation with TTE during the clinical follow-up can be useful to detect LoRVF. However a persistent elevated PCWP is not associated with echocardiographic signs of incomplete unloading of the LV by the LVAD.

P1670Incidence and prognosis of late-onset right ventricular failure following continuous-flow left ventricular assist device implantation as bridge to transplantation

Abstract Early right ventricular failure (RVF) remains a frequent complication and is one of the main factors associated to early mortality following left ventricular assist device (LVAD) implantation. However, late-onset RVF (LoRVF) has emerged as an increasing concern, but little is known about its incidenceand underlying mechanisms. Methods and results We retrospectively analysed the 1-year hemodynamic and clinical data from all patients that, between 2016 and 2018, underwent a right heart catheterization (RHC) after continuous-flow LVAD implantation as bridge to transplantation. Sixty-six patients (84% males, 53±11 years, 60% implanted in Intermacs 1–2, 52% HeartWare LVAD, 48% HM3 LVAD), out of 187 LVAD implants, were studied. LoRVF was defined as central venous pressure&gt;18 mmHg with cardiac index&lt;2.3 L/min/m2 during RHC. LoRVF was present in 17 patients (25.7%) and 12 (71%) of them manifested concomitant clinical signs of RVF. Eleven of the patients who presented LoRVF (65% of the LoRVF) had a pulmonary capillary wedge pressure (PCWP)&gt;15 mmHg. Isolated LoRVF (LoRVF criteria + PCWP≤15 mmhg) was found in 6 patients (35% of the LoRVF) and accounted for 9% of the studied population. Fifty percent of patients who presented isolated LoRVF could be successfully transplanted in high urgent status due to severe chronic RVF and 1 patient died to refractory RVF. We did not find an association between isolated LoRVF and age, renal function, type of LVAD, persistent increased pulmonary vascular resistances or the previous need of temporary right ventricular support due to early acute RVF following LVAD. There was however a significant association between the presence of atrial fibrillation and isolated LoRVF (p&lt;0.05). Incidence and prognosis of LoRVF Conclusion Late-onset RVF is a frequent complication during LVAD support as bridge to transplantation. Most of the cases are associated to a lesser degree of left ventricular unloading. The presence of isolated late-onset RVF with normal PCWP has an impact on the long-term prognosis and the need of urgent heart transplantation and is not related to early RVF following LVAD implantation or persistent increased pulmonary vascular resistance.

Left Ventricular Assist Device Flow Pattern Analysis Utilizing a Novel Computational Fluid Dynamics Model: Using Physics and Physiology to Better Define the Pump-Patient Interaction

Introduction Blood flow patterns through the left ventricular assist device (LVAD) and aorta remain incompletely understood. Computational fluid dynamics (CFD) allows for analysis of flow in the cardiovascular system although current LVAD models have failed to fully incorporate the interplay between the pulsatile left ventricle and continuous-flow generated by the LVAD. Hypothesis Flow through the LVAD is dependent on the interaction between device and patient specific factors with suboptimal flow patterns evoking increased risk of LVAD-related complications. CFD can be used to analyze how different pump and patient factors affect flow through the system. Methods CFD simulations were carried out on a patient with a HeartMate II (HMII) (Fig A). Simulations were also done substituting HeartWare HVAD (Fig B), HeartMate 3 (HM3) in continuous mode (Fig C) and HM3 with Artificial Pulse (Fig D). An anatomical model of the patient was reconstructed from CT images. The LVAD flow was calculated separately using a lumped-parameter-model (LPM), which was calibrated to the patient based on the patient-specific ventricular volume change reconstructed from 4 dimensional CT and hemodynamic tracings. The LVADs were implemented in the LPM via published H-Q curves. In order to quantify the flushing effect, virtual contrast agent was released in the ascending aorta and its flushing over the cycles was quantified. Results Under standard operation conditions of the LVADs (9200 RPM for HMII, 5500 RPM for HM3 and 2600 RPM for HVAD), the cardiac outputs were 5.92 L/min, 6.14 L/min and 6.90 L/min, for HMII, HM3 and HVAD, respectively. The velocity of blood flow in the outflow cannula was higher in the HVAD than in the two HeartMate pumps with a cycle average (range) of 0.72 m/s (0.57-0.93 m/s), 0.70 m/s (0.64-0.77 m/s) and 1.61 m/s (1.21-1.92 m/s) for HMII, HM3 and HVAD, respectively. Artificial Pulse increased the peak flow rate to 9.84 L/min for the HM3 but the overall cardiac output was 5.96 L/min, which was similar to the continuous mode (Fig E). Artificial pulse markedly accelerated flushing of the blood from the ascending aorta; after 6 cardiac cycles, 43% of the blood was flushed out from the ascending aorta under the continuous operation mode while 61% was flushed under artificial pulse (Fig F). Conclusions Pump-specific factors such as LVAD type and programmed flow algorithms lead to unique flow patterns that can be studied using a novel CFD model to better understand and potentially mitigate the risk of downstream LVAD complications.

Post-Cardiac Transplant Survival of Patients Supported by the Heartmate 3 Devices: A UNOS Analysis

Introduction Post cardiac transplant outcomes of patients supported with the Heartmate 3 left ventricular assist device (LVAD) have not been previously reported. The purpose of this analysis was to report status at the time of transplant and survival by continuous flow (CF) device type. Hypothesis Patients supported with a HeartMate 3 LVAD will have a similar post-transplant survival to other contemporary CF-LVADs. Methods The study cohort included adult patients supported on contemporary, continuous flow (CF) devices in the UNOS registry who underwent cardiac transplant between the years 2014-2018, prior to the 2018 UNOS allocation system change. The analysis was limited to patients who underwent initial LVAD implantation in 2014 and beyond to allow post-transplant comparisons among patients with similar LVAD support times. Multivariable cox regression was performed to assess the association between LVAD type and post-transplant survival. Results The study cohort consisted of 3,117 patients who underwent cardiac transplant while on LVAD support (Heartmate 2: 1,545, Heartmate 3: 179, HeartWare (HVAD): 1,393). No patients supported on Heartmate 3 devices were transplanted for pump thrombosis during this time period. Patients supported on the Heartmate 3 were less likely to be listed 1A for complications at the time of transplant (Heartmate3: 28 % (51/179), Heartmate 2: 44 % (680/1,545), HVAD 37 % (511/1,393, p Conclusions Patients supported with Heartmate 3 LVAD at the time of transplant have similar survival after transplant compared to other contemporary CF devices in this early experience. No patients with a Heartmate 3 were transplanted for device thrombosis.

Rates of and Risk Factors for CMV Reactivation Following LVAD Implantation

Introduction While cytomegalovirus (CMV) reactivation occurs frequently in immunocompetent patients who are critically ill and has been associated with worse outcomes, very few cases of CMV reactivation have been reported following left ventricular assist device (LVAD) implantation. We aimed to evaluate the incidence and risk factors for CMV reactivation following LVAD implantation as well as treatment strategies for these CMV infections. Methods Retrospective chart review of patients of patients who had undergone LVAD implantation between July 2004 and January 2019 was performed. Cases with CMV reactivation post-LVAD were randomly matched by sex, LVAD type, and implant year in a 1:2 fashion with controls utilizing SAS macros. Days-to-reactivation post-implantation were calculated in cases and corresponding times post-implantation were determined in control patients for variable comparisons. Fisher's exact and paired sample t-tests were performed to evaluate for differences between categorical and continuous variables, respectively. Results Of the 349 patients reviewed, 213 (61%) patients were positive for CMV IgG prior to LVAD implantation. Of these 213 patients, 8 (3.8%) patients had CMV reactivation following LVAD implantation. Six (75%) of the 8 patients had CMV viremia, while the other 2 had colitis and pneumonia without evidence of viremia. Full between group comparisons are listed in Figure 1. In comparison to matched controls, patients who had CMV reactivation had a higher creatinine (p=0.039), higher RDW (p=0.05), were more likely to have received steroids within the previous week (p=0.028), and were more likely to have a concurrent bacterial infection (p=0.001). Seven (87.5%) of the 8 patients underwent treatment for their CMV reactivation, with all of them receiving intravenous ganciclovir as initial therapy. The one patient who did not receive treatment had low level viremia and was asymptomatic. Full description of the management of the CMV reactivation cohort is listed in Figure 2. Conclusions CMV reactivation following LVAD implantation is more frequent than previously expected. Awareness of this clinical entity for early testing, diagnosis, and treatment in at risk patients (i.e. renal failure, steroid use, elevated RDW) is important to ensuring good clinical outcomes.

Outcomes after heart transplantation in sensitized patients bridged with ventricular assist devices.

Sensitization has been associated with worse outcomes following heart transplantation (HTx). The use of ventricular assist devices (VAD) is a risk factor for the development of sensitization. We investigated the impact of left ventricular assist devices (LVAD) and sensitization in HTx recipients. We queried the UNOS database for all heart transplants performed from January 2000 through December 2016. Patients were considered highly sensitized and included if panel-reactive antibody (PRA) activity was 25% or higher. Patients were separated by pretransplant LVAD utilization and subgroup analysis was performed by device type (HeartMate II or HeartWare). Outcomes included Kaplan-Meier survival and episodes of rejection within 1 year of HTx. Of 18 009 recipients, 2434 (14%) were highly sensitized. 1055 (43.3%) were bridged with a VAD. In multivariate analysis, LVAD use did not impact 1-year (hazards ratio [HR], 1.30; P = 0.052) or 5-year survival (HR, 1.18; P = 0.112) in highly sensitized recipients. Furthermore, episodes of rejection were not affected by LVAD status (P = 0.765). Of the 1055 sensitized LVAD-bridged transplant recipients, 624 (59%) were implanted with a HeartMate II and 99 (9.4%) were bridged with a HeartWare device. In multivariate analysis, no differences were observed in 1-year survival (HR, 0.86; P = 0.664), 5-year survival (HR, 1.35; P = 0.209), or episodes of rejection (P = 0.497). The use of ventricular assist devices did not impact survival or rejection within 1 year of HTx in highly sensitized patients. Highly sensitized recipients have similar outcomes regardless of prior LVAD support or type of LVAD used as a bridge to transplantation.