Ventricular Assist Device Implantation Research Articles

Use of Levosimendan in patients with INTERMACS 3 profile: weaning from inotropic support and short- to medium-term evolution

Abstract Funding Acknowledgements None. Introduction Patients with advanced heart failure (HF) in cardiogenic shock (CS) present a markedly high mortality rate. For CS patients dependent on inotropes, management is difficult with few therapeutic options available, especially in the absence of a suitability for heart transplantation (HTX) or left ventricular assist device implantation (LVAD), thus associating an even worse prognosis. Purpose With our study we aim to analyse the rate of weaning from inotropic support when Levosimendan, a calcium sensitizer with positive inotropic effects, is used in INTERMACS 3 CS patients and their short to medium-term evolution. We then evaluate if the absence of right ventricular dysfunction, of renal dysfunction, non-ischemic aetiology and QRS width could be predicting factors of a successful weaning from inotropes. Materials and methods We conducted a monocentric retrospective analysis of patients from a tertiary cardiac intensive care unit that have received a 24 hours Levosimendan infusion in the context of INTERMACS 3 cardiogenic shock between August 2015 – April 2023. Results Of the 137 subjects included in the analysis, 62 patients received Levosimendan for INTERMACS 3 CS. The median age was 59±15.3 and 91.9% (n=57) were male. Baseline LVEF was 19±6%, cardiac index 1.67±0.4L/min/m2, median NTproBNP 13 378 ± 11 126ng/L. 51.6% (n=32) had ischemic heart disease and 40.3% (n=25) had dilated cardiomyopathy. After Heart Team discussion, only 37% (n=23) were considered eligible for HTX or LVAD. Successful inotrope weaning was experienced in 68% (n=42). Amongst patients with weaning failure, most outcomes resulted in either death (45%), ambulatory continuous Dobutamine infusion (30%), or benefited from a HTX if eligible (15%). The weaning failure rates were similar amongst patients eligible and non-eligible to HTX or LVAD with different outcomes after weaning failure as shown in Figure 1. The overall survival rates at 1 month and 6 months were of 83.8% and 53.2% respectively, with a significant difference between survival rates according to inotrope weaning success or failure as shown in Figure 2. We found no clinical, biological, or echocardiographic parameter to be significantly associated with an increased probability of weaning. Conclusion Levosimendan use in INTERMACS 3 CS patients provides a good rate of success in weaning from inotropic support and could be a useful tool in allowing treatment optimization and stabilization in non HTX or LVAD eligible patients, as well as being a "bridge to transplantation" alternative. No predicting factors for successful weaning have been identified.

Prognostic implications of delirium after Left Ventricular Assist Device (LVAD) implantation: A retrospective study

IntroductionIn critically ill patients, delirium is a prognostic indicator of morbidity and mortality. This study investigates the impact of a delirium diagnosis on outcomes after Left Ventricular Assist Device (LVAD) implantation. MethodsThis retrospective study included all adult patients who received LVADs at our institution between January 2016 and December 2020. We compared pre-implantation characteristics between the two groups, with and without a diagnosis of delirium, and compared their outcomes, including 1-month, 6-month, and in-hospital mortality, as well as re-intubation rate, length of stay (LOS), discharge disposition, and readmission rates. ResultsIn total, 361 patients (26.7% women, 75.8% African American) received durable LVADs. Ninety-four patients (26.1%) were diagnosed with delirium during the index admission. Pre-implantation demographic characteristics, past medical and psychiatric conditions, Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profile, and laboratory values did not differ between the two groups with and without a diagnosis of delirium; older age (59 vs 56; P=0.03) was associated with delirium. Delirium diagnosis was associated with higher 1-month (P=0.007), 6-month (P=0.004), and in-hospital mortality (P<0.001), unplanned re-intubations (P<0.001), and a lower likelihood of discharge home (P = 0.03). Total hospital and ICU LOS were higher in patients with a diagnosis of delirium, though these results were not statistically significant. Readmission to hospital after index admission was quicker in patients with a diagnosis of delirium, but this result was not statistically significant. ConclusionsIn this study, a diagnosis of delirium during the LVAD implantation admission was associated with higher mortality, adverse post-surgical outcomes, and unfavorable discharge dispositions. Future prospective research is needed to validate the prognostic implications of delirium in both the short and long term. Additionally, there is a need to identify modifiable risk factors associated with delirium to promote early diagnosis and implement evidence-based management strategies to enhance outcomes within this population.

Outcomes and Complications after Left Ventricular Assist Device Implantation

Heart transplantation is the treatment of choice for selected patients with end-stage heart failure. Persistent donor organ shortage causes a growing demand for mechanical circulatory support not only as a bridge to transplantation but mainly as a destination therapy (DT). The aim of the study was to analyze the indications, comorbidities, and complications during the follow-up of all patients undergoing left ventricular assist device (LVAD) implantation with at least 12 months of follow-up time in one of the most experienced clinics in Poland between 2015 and 2023. There were 125 individuals with LVAD implantation, from which 90 had full 12 months of follow-up (85 males - 94%, 5 females - 6%), with a median age of 58 (50.25-63.75) years. The median body mass index was 27.12 (25.27-29.68). The etiology of heart failure was ischemic (n = 44, 49%), dilated cardiomyopathy (n = 44, 49%), and others. Preoperative echocardiography revealed a mean LV ejection fraction of 13.8% and a median LV dimension of 7.55 (6.92-8.2) cm. In 61 patients (68%), imaging confirmed pulmonary hypertension. Thirty-four patients (38%) had diabetes and 16 (18%) were active smokers. Median follow-up was 30 (17.25-42) months, with the longest period being about 82 months. 40 (44%) patients had kidney failure before LVAD implantation, and in 43 cases (48%), we observed relevant, transient deterioration of kidney function. Almost all patients (n = 82, 91%) suffered from anemia (Hb <13 g/dL in males and <12 g/dL in females) in different periods after LVAD implantation due to perioperative bleeding, gastrointestinal bleeding or unknown causes. The lowest Hb level was observed in the first week after LVAD implantation in 53 cases (58%). Median red cell concentrate transfusion demand before the discharge after surgery was 6 (2-8, 5) units. Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of DT. Anemia and kidney failure are the most frequent follow-up complications. Improved results and increased applicability and durability of LVADs have established this treatment option as an excellent alternative for patients with end-stage heart failure.

D-9 | Choice of temporary mechanical circulatory support in patients undergoing left ventricular assist device implantation

D-9 | Choice of temporary mechanical circulatory support in patients undergoing left ventricular assist device implantation

Predictors and Impact of Prolonged Vasoplegia After Continuous-Flow Left Ventricular Assist Device Implantation

BackgroundVasoplegia after cardiac surgery is associated with adverse outcomes. However, the clinical effects of vasoplegia and the significance of its duration after continuous-flow left ventricular assist device (CF-LVAD) implantation are less known. ObjectivesThis study aimed to identify predictors of and outcomes from transient vs prolonged vasoplegia after CF-LVAD implantation. MethodsThe study was a retrospective review of consecutive patients who underwent CF-LVAD implantation between January 1, 2005, and December 31, 2017. Vasoplegia was defined as the presence of all of the following: mean arterial pressure ≤65 mm Hg, vasopressor (epinephrine, norepinephrine, vasopressin, or dopamine) use for >6 hours within the first 24 hours postoperatively, cardiac index ≥2.2 L/min/m2 and systemic vascular resistance <800 dyn/s/cm5, and vasodilatory shock not attributable to other causes. Prolonged vasoplegia was defined as that lasting 12 to 24 hours; transient vasoplegia was that lasting 6 to <12 hours. Patient characteristics, outcomes, and risk factors were analyzed. ResultsOf the 600 patients who underwent CF-LVAD implantation during the study period, 182 (30.3%) developed vasoplegia. Mean patient age was similar between the vasoplegia and no-vasoplegia groups. Prolonged vasoplegia (n = 78; 13.0%), compared with transient vasoplegia (n = 104; 17.3%), was associated with greater 30-day mortality (16.7% vs 5.8%; P = 0.02). Risk factors for prolonged vasoplegia included preoperative dialysis and elevated body mass index. ConclusionsCompared with vasoplegia overall, prolonged vasoplegia was associated with worse survival after CF-LVAD implantation. Treatment to avoid or minimize progression to prolonged vasoplegia may be warranted.

[Prognostic performance of pulmonary effective arterial elastance in patients with heart failure].

Objective: To explore the predictive value of pulmonary effective arterial elastance (Ea) in patients with heart failure (HF). Methods: This is a retrospective cohort study, which retrospectively included 284 patients with HF who underwent right heart catheterization at Heart Failure Center in Fuwai Hospital between September 2013 and February 2022. Data regarding baseline clinical characteristics, hemodynamic profiles, and prognosis were collected. Ea was calculated as mean pulmonary arterial pressure/stroke volume. Patients were divided into Ea<0.555 group and Ea≥0.555 group according to the median value of Ea (0.555 mmHg/ml, 1 mmHg=0.133 kPa). The primary outcome was the primary clinical event, set as the first occurrence of a series of composite events, including all-cause death, heart transplantation, left ventricular assist device implantation, and HF rehospitalization. Event-free survival was defined as the absence of primary clinical events. Spearman correlation analysis was used to calculate the correlation coefficient between Ea and parameters reflective of right heart function. The Kaplan-Meier analysis was used to compare the different groups for the estimation of outcomes with the log-rank test. We used Cox proportional-hazards regression models to estimate hazard ratios (HR) for primary clinical event. Subgroup analysis was performed based on the age, gender, New York Heart Association (NYHA) functional class, left ventricular ejection fraction, presence of pulmonary hypertension, and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) values. We used receiver operating characteristic (ROC) curve to calculate the area under the curve (AUC) of Ea for predicting event-free survival in patients with HF. Results: The median age was 51 years, and 206 (72.5%) patients were male. Ea and pulmonary vascular resistance (PVR) were significantly correlated (r=0.698, P<0.001). The correlation between Ea and pulmonary arterial elastance (PAC) were even more significant (r=-0.888, P<0.001). Compared with Ea<0.555 group, Ea≥0.555 group presented with higher serum NT-proBNP values (4 443 (1 792, 8 554) ng/L vs. 1 721 (480, 4 528)ng/L,P<0.001), higher PVR (3.4 (2.5, 4.7) Wood vs. 1.4 (0.9, 2.2) Wood, P<0.001), lower cardiac output (3.0 (2.3, 3.9) L/min vs. 4.3 (3.8, 4.9) L/min, P<0.001), and lower PAC (1.6 (1.3, 2.0) ml/mmHg vs. 4.0 (3.0, 6.0) ml/mmHg, P<0.001). The median follow-up time was 392 (166, 811) days. The Kaplan-Meier survival curve demonstrated a lower event-free survival rate in the Ea≥0.555 group compared to the Ea<0.555 group (Plog-rank<0.001). After multivariate adjustment, Ea (HR=1.734, P<0.001) remained significantly associated with the primary outcome. Subgroup analysis indicated that Ea was associated with the primary outcome across all subgroups. The AUC was 0.724 (P<0.001) for Ea to predict event-free survival calculated from ROC analysis. Conclusions: Ea is closely related to parameters reflective of right ventricular afterload. Increased Ea is an independent predictor of adverse outcomes in patients with HF.

Temporal Analysis in Outcomes of Long-Term Mechanical Circulatory Support: Retrospective Study.

Mechanical assist device indications have changed in recent years. Reduced incidence of complications, better survival, and the third generation of mechanical support devices contributed to this change. In this single-center study, we focused on two time periods that are characterized by the use of different types of mechanical support devices, different patient characteristics, and change in the indications. The data were processed from the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). We retrospectively defined two time intervals to reflect changes in ventricular assist device technology (period 1: 2007-2015; period 2: 2016-20222). A total of 181 patients underwent left ventricular assist device implantation. Device utilization was the following: HeartMate II = 52 (76.4%) and HeartWare = 16 (23.6%) in period 1 and HeartMate II = 2 (1.8%), HeartMate 3 = 70 (61:9%), HeartWare = 29 (25.7%), SynCardia TAH = 10 (8.8%), and BerlinHeart EXCOR = 2 (1.8%) in period 2. The outcomes of the time intervals were analyzed and evaluated. Survival was significantly higher during the second time period. Multivariate analysis revealed that age and bypass pump time are independent predictors of mortality. Idiopathic cardiomyopathy, bypass time, and the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) score are independent predictors of adverse events. Furthermore, the first period was noted to be at an increased risk of the following adverse events: pump thrombosis, gastrointestinal bleeding, and bleeding events. Despite the higher risk profile of the patients and persistent challenges, during the second period, there was a significant decrease in mortality and morbidity. The use of the HeartMate 3 device may have contributed to this result.

Noncardiac Surgery in Patients with Left Ventricular Assist Devices: A 11-Year Institutional Experience.

Limited options in the end-stage treatment of heart failure have led to increased use of left ventricular assist devices. For this reason, the rate of non-cardiac surgeries in patients with left ventricular assist devices is also increasing. Our study aims to analyze surgical rate, anesthesia management, and results by reviewing our 11-year experience with patients who underwent non-cardiac surgery receiving left ventricular assist devices support. We retrospectively evaluated 57 patients who underwent non-cardiac surgery and 67 non-cardiac surgical procedures among 274 patients who applied between January 2011 and December 2022 and underwent left ventricular assist devices implantation with end-stage heart failure. Fifty (74.6%) patients with left ventricular assist devices admitted to the hospital for non-cardiac surgery were emergency interventions. The most common reasons for admission were general surgery (52.2%), driveline wound revision (22.3%), and neurological surgery (14.9%). This patient group has the highest in-hospital mortality rate (12.8%) and the highest rate of neurological surgery (8.7%). While 70% of the patients who underwent neurosurgery were taken to surgery urgently, the International Normalized Ratio values of these patients were between 3.5 and 4.5 at the time of admission to the emergency department. With a perioperative multidisciplinary approach, higher morbidity and mortality risks can be reduced during emergencies and major surgical procedures.

Endomyocardial biopsy: safety and prognostic utility in paediatric and adult myocarditis in the European Society of Cardiology EURObservational Research Programme Cardiomyopathy and Myocarditis Long-Term Registry.

Contemporary multicentre data on clinical and diagnostic spectrum and outcome in myocarditis are limited. Study aims were to describe baseline features, 1-year follow-up, and baseline predictors of outcome in clinically suspected or biopsy-proven myocarditis (2013 European Society of Cardiology criteria) in adult and paediatric patients from the EURObservational Research Programme Cardiomyopathy and Myocarditis Long-Term Registry. Five hundred eighty-one (68.0% male) patients, 493 adults, median age 38 (27-52) years, and 88 children, aged 8 (3-13) years, were divided into 3 groups: Group 1 (n = 233), clinically suspected myocarditis with abnormal cardiac magnetic resonance; Group 2 (n = 222), biopsy-proven myocarditis; and Group 3 (n = 126) clinically suspected myocarditis with normal or inconclusive or no cardiac magnetic resonance. Baseline features were analysed overall, in adults vs. children, and among groups. One-year outcome events included death/heart transplantation, ventricular assist device (VAD) or implantable cardioverter defibrillator (ICD) implantation, and hospitalization for cardiac causes. Endomyocardial biopsy, mainly right ventricular, had a similarly low complication rate in children and adults (4.7% vs. 4.9%, P = NS), with no procedure-related death. A classical myocarditis pattern on cardiac magnetic resonance was found in 31.3% of children and in 57.9% of adults with biopsy-proven myocarditis (P < .001). At 1-year follow-up, 11/410 patients (2.7%) died, 7 (1.7%) received a heart transplant, 3 underwent VAD (0.7%), and 16 (3.9%) underwent ICD implantation. Independent predictors at diagnosis of death or heart transplantation or hospitalization or VAD implantation or ICD implantation at 1-year follow-up were lower left ventricular ejection fraction and the need for immunosuppressants for new myocarditis diagnosis refractory to non-aetiology-driven therapy. Endomyocardial biopsy was safe, and cardiac magnetic resonance using Lake Louise criteria was less sensitive, particularly in children. Virus-negative lymphocytic myocarditis was predominant both in children and adults, and use of immunosuppressive treatments was low. Lower left ventricular ejection fraction and the need for immunosuppressants at diagnosis were independent predictors of unfavourable outcome events at 1 year.

Management of aortic valve insufficiency in patients with continuous-flow left ventricular assist device: a republication of the review published in Japanese Journal of Artificial Organs.

Since 2011, implantable ventricular assist devices have been a standard treatment for severe heart failure alongside heart transplantation in Japan. However, the limited availability of donors has led to a prolonged wait for transplants, now averaging 1719days, intensifying the issue of aortic insufficiency in patients with continuous flow ventricular assist devices. These devices limit the opening of the aortic valve, leading to sustained closure and increased shear stress, which accelerates valve degradation. Risk factors for aortic insufficiency include having a smaller body surface area, being of advanced age, and the presence of mild aortic insufficiency prior to device implantation. In patients presenting with mild or moderate aortic regurgitation at the time of ventricular assist device implantation, interventions such as aortic valve repair or bioprosthetic valve replacement are performed with the aim of halting its progression. The choice of surgical procedure should be tailored to each patient's individual condition. The management of de novo aortic insufficiency in patients with continuous flow ventricular assist devices remains challenging, with no clear consensus on when to intervene. Interventions for significant aortic insufficiency typically consider the patient's symptoms and aortic insufficiency severity. De novo aortic insufficiency progression in continuous flow ventricular assist devices patients necessitates careful monitoring and intervention based on individual patient assessments and valve condition. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 77-80), with some modifications.

Outcomes of left ventricular assist device implantations at Karolinska University Hospital: A retrospective study

ObjectiveTo descriptively present data and outcomes of Left ventricular assist device (LVAD) implantations at Karolinska University hospital. MethodsData were collected from consecutive patients (n=44) who were implanted with HeartMate 3 (HM3) at Karolinska University Hospital between 2017 and 2022. The study presents baseline characteristics, clinical course during the inpatient hospital care after implantation, adverse events, and clinical outcomes. ResultsMedian intensive care unit stay and hospital stay after HM3 implantation was 8 (interquartile range [IQR] 6; 15) and 28 days (IQR 22; 36), respectively. In total, 73% underwent ramp test at some point after the implantation. Death from all causes within 30 days post-implantation was 5%. A total of 21 patients (48%) underwent right heart catheterization, at a median of 0.5 years (IQR 0.3;0.7) after implantation, and all exhibited optimally unloaded left ventricles. During the study period, 34% of the patients were transplanted, 5% were explanted, and 16% died with LVAD. In total, 11% and 5% suffered from early and late right ventricle failure, respectively. Acute renal failure affected 46% and 18% had drive-line infection. Spontaneous cerebral haemorrhage and cerebral infarction affected 5% and 7% of the study population, respectively. Gastrointestinal bleeding affected 16%. The median LVAD-duration was 10 months (IQR 5;22). The one-year survival rate with LVAD was 85%, and the two-year survival rate was 80%. ConclusionsThe results of this low volume single-center retrospective study on LVAD implantations align with the results of other studies and international registries.

(1311) - Nutritional Risk Assessment and Adverse Events in Patients Undergoing Left Ventricular Assist Device Implantation - A Retrospective Cohort Study Using Hospital Information System

(1311) - Nutritional Risk Assessment and Adverse Events in Patients Undergoing Left Ventricular Assist Device Implantation - A Retrospective Cohort Study Using Hospital Information System

Pregnancy in women with dilated cardiomyopathy genetic variants

Introduction and objectives: Limited information is available on the safety of pregnancy in patients with genetic dilated cardiomyopathy (DCM) and in carriers of DCM-causing genetic variants without the DCM phenotype. We assessed cardiac, obstetric, and fetal or neonatal outcomes in this group of patients.Methods: We studied 48 women carrying pathogenic or likely pathogenic DCM-associated variants (30 with DCM and 18 without DCM) who had 83 pregnancies. Adverse cardiac events were defined as heart failure (HF), sustained ventricular tachycardia, ventricular assist device implantation, heart transplant, and/or maternal cardiac death during pregnancy, or labor and delivery, and up to the sixth postpartum month.Results: A total of 15 patients, all with DCM (31% of the total cohort and 50% of women with DCM) experienced adverse cardiac events. Obstetric and fetal or neonatal complications were observed in 14% of pregnancies (10 in DCM patients and 2 in genetic carriers). We analyzed the 30 women who had been evaluated before their first pregnancy (12 with overt DCM and 18 without the phenotype). Five of the 12 (42%) women with DCM had adverse cardiac events despite showing NYHA class I or II before pregnancy. Most of these women had a history of cardiac events before pregnancy (80%). Among the 18 women without phenotype, 3 (17%) developed DCM toward the end of pregnancy.Conclusions: Cardiac complications during pregnancy and postpartum were common in patients with genetic DCM and were primarily related to HF. Despite apparently good tolerance of pregnancy in unaffected genetic carriers, pregnancy may act as a trigger for DCM onset in a subset of these women.

(1370) - Exploring Factors Associated with Prolonged Intubation After Ventricular Assist Device Implantation in Children

(1370) - Exploring Factors Associated with Prolonged Intubation After Ventricular Assist Device Implantation in Children

(110) - Mitral Regurgitation at the Time of Left Ventricular Assist Device Implantation - Should We Treat It or Not?

(110) - Mitral Regurgitation at the Time of Left Ventricular Assist Device Implantation - Should We Treat It or Not?

Arrhythmic manifestations and outcomes of definite and probable cardiac sarcoidosis

BackgroundThe 2014 Heart Rhythm Society consensus statement defines histological (definite) and clinical (probable) diagnostic categories of cardiac sarcoidosis (CS), but few studies have compared their arrhythmic phenotypes and outcomes. ObjectiveThe purpose of this study was to evaluate the electrophysiological/arrhythmic phenotype and outcomes of patients with definite and probable CS. MethodsWe analyzed the arrhythmic/electrophysiological phenotype in a single-center North American cohort of 388 patients (median age 56 years; 39% female) diagnosed with definite (n = 58) or probable (n = 330) CS (2000–2022). The primary composite outcome was survival to first ventricular tachycardia/fibrillation (VT/VF) event or sudden cardiac death. Key secondary outcomes were also assessed. ResultsAt index evaluation, in situ cardiac implantable electronic devices and antiarrhythmic drug use were more common in definite CS. At a median follow-up of 3.1 years, the primary outcome occurred in 22 patients with definite CS (38%) and 127 patients with probable CS (38%) (log-rank, P = .55). In multivariable analysis, only a higher ratio of the 18F-fluorodeoxyglucose maximum standardized uptake value of the myocardium to the maximum standardized uptake value of the blood pool (hazard ratio 1.09; 95% confidence interval 1.03–1.15; P = .003, per 1 unit increase) was associated with the primary outcome. During follow-up, patients with definite CS had a higher burden of device-treated VT/VF events (mean 2.86 events per patient-year vs 1.56 events per patient-year) and a higher rate of progression to heart transplant/left ventricular assist device implantation but no difference in all-cause mortality compared with patients with probable CS. ConclusionPatients with definite and probable CS had similarly high risks of first sustained VT/VF/sudden cardiac death and all-cause death, though patients with definite CS had a higher overall arrhythmic burden. Both CS diagnostic groups as defined by the 2014 Heart Rhythm Society criteria require an aggressive approach to prevent arrhythmic complications.

(109) - Incidence and Risk Factors for Early Stroke Following Durable Left Ventricular Assist Device (LVAD) Implantation: An STS Intermacs Analysis

(109) - Incidence and Risk Factors for Early Stroke Following Durable Left Ventricular Assist Device (LVAD) Implantation: An STS Intermacs Analysis

(837) - Trending Renal Function Pre- and Post-Left Ventricular Assist Device (LVAD) Implantation

(837) - Trending Renal Function Pre- and Post-Left Ventricular Assist Device (LVAD) Implantation

(1235) - Patient Outcomes Following Emergency Ventricular Assist Device Implantation During High-Urgency Waiting Period for Heart Transplantation

(1235) - Patient Outcomes Following Emergency Ventricular Assist Device Implantation During High-Urgency Waiting Period for Heart Transplantation

(874) - Usefulness of Established Risk Scores in Predicting Right Heart Failure Requiring Temporary Right Ventricular Assist Device Support Following Left Ventricular Assist Device Implantation

(874) - Usefulness of Established Risk Scores in Predicting Right Heart Failure Requiring Temporary Right Ventricular Assist Device Support Following Left Ventricular Assist Device Implantation