Chronic Left Ventricular Assist Device Support Research Articles

Right heart failure with left ventricular assist devices: Preoperative, perioperative and postoperative management strategies. A clinical consensus statement of the Heart Failure Association (HFA) of the ESC.

Right heart failure (RHF) following implantation of a left ventricular assist device (LVAD) is a common and potentially serious condition with a wide spectrum of clinical presentations with an unfavourable effect on patient outcomes. Clinical scores that predict the occurrence of right ventricular (RV) failure have included multiple clinical, biochemical, imaging and haemodynamic parameters. However, unless the right ventricle is overtly dysfunctional with end-organ involvement, prediction of RHF post-LVAD implantation is, in most cases, difficult and inaccurate. For these reasons optimization of RV function in every patient is a reasonable practice aiming at preparing the right ventricle for a new and challenging haemodynamic environment after LVAD implantation. To this end, the institution of diuretics, inotropes and even temporary mechanical circulatory support may improve RV function, thereby preparing it for a better adaptation post-LVAD implantation. Furthermore, meticulous management of patients during the perioperative and immediate postoperative period should facilitate identification of RV failure refractory to medication. When RHF occurs late during chronic LVAD support, this is associated with worse long-term outcomes. Careful monitoring of RV function and characterization of the origination deficit should therefore continue throughout the patient's entire follow-up. Despite the useful information provided by the echocardiogram with respect to RV function, right heart catheterization frequently offers additional support for the assessment and optimization of RV function in LVAD-supported patients. In any patient candidate for LVAD therapy, evaluation and treatment of RV function and failure should be assessed in a multidimensional and multidisciplinary manner.

Machine Learning Multicenter Risk Model to Predict Right Ventricular Failure After Mechanical Circulatory Support

The existing models predicting right ventricular failure (RVF) after durable left ventricular assist device (LVAD) support might be limited, partly due to lack of external validation, marginal predictive power, and absence of intraoperative characteristics. To derive and validate a risk model to predict RVF after LVAD implantation. This was a hybrid prospective-retrospective multicenter cohort study conducted from April 2008 to July 2019 of patients with advanced heart failure (HF) requiring continuous-flow LVAD. The derivation cohort included patients enrolled at 5 institutions. The external validation cohort included patients enrolled at a sixth institution within the same period. Study data were analyzed October 2022 to August 2023. Study participants underwent chronic continuous-flow LVAD support. The primary outcome was RVF incidence, defined as the need for RV assist device or intravenous inotropes for greater than 14 days. Bootstrap imputation and adaptive least absolute shrinkage and selection operator variable selection techniques were used to derive a predictive model. An RVF risk calculator (STOP-RVF) was then developed and subsequently externally validated, which can provide personalized quantification of the risk for LVAD candidates. Its predictive accuracy was compared with previously published RVF scores. The derivation cohort included 798 patients (mean [SE] age, 56.1 [13.2] years; 668 male [83.7%]). The external validation cohort included 327 patients. RVF developed in 193 of 798 patients (24.2%) in the derivation cohort and 107 of 327 patients (32.7%) in the validation cohort. Preimplant variables associated with postoperative RVF included nonischemic cardiomyopathy, intra-aortic balloon pump, microaxial percutaneous left ventricular assist device/venoarterial extracorporeal membrane oxygenation, LVAD configuration, Interagency Registry for Mechanically Assisted Circulatory Support profiles 1 to 2, right atrial/pulmonary capillary wedge pressure ratio, use of angiotensin-converting enzyme inhibitors, platelet count, and serum sodium, albumin, and creatinine levels. Inclusion of intraoperative characteristics did not improve model performance. The calculator achieved a C statistic of 0.75 (95% CI, 0.71-0.79) in the derivation cohort and 0.73 (95% CI, 0.67-0.80) in the validation cohort. Cumulative survival was higher in patients composing the low-risk group (estimated <20% RVF risk) compared with those in the higher-risk groups. The STOP-RVF risk calculator exhibited a significantly better performance than commonly used risk scores proposed by Kormos et al (C statistic, 0.58; 95% CI, 0.53-0.63) and Drakos et al (C statistic, 0.62; 95% CI, 0.57-0.67). Implementing routine clinical data, this multicenter cohort study derived and validated the STOP-RVF calculator as a personalized risk assessment tool for the prediction of RVF and RVF-associated all-cause mortality.

Feasibility of high-intensity interval training in patients with left ventricular assist devices: a pilot study.

AimsPatients with left ventricular assist device (LVAD) suffer from persistent exercise limitation despite improvement of their heart failure syndrome. Exercise training (ET) programmes to improve aerobic capacity have shown modest efficacy. High‐intensity interval training (HIIT), as an alternative to moderate continuous training, has not been systematically tested in this population. We examine the feasibility of a short, personalized HIIT programme in patients with LVAD and describe its effects on aerobic capacity and left ventricular remodelling.Methods and resultsPatients on durable LVAD support were prospectively enrolled in a 15‐session, 5 week HIIT programme. Turndown echocardiogram, Kansas City Cardiomyopathy Questionnaire, and cardiopulmonary exercise test were performed before and after HIIT. Training workloads for each subject were based on pretraining peak cardiopulmonary exercise test work rate (W). Percentage of prescribed training workload completed and adverse events were recorded for each subject. Fifteen subjects were enrolled [10 men, age = 51 (29–71) years, HeartMate II = 12, HeartMate 3 = 3, and time on LVAD = 18 (3–64) months]. Twelve completed post‐training testing. HIIT was well tolerated, and 90% (inter‐quartile range: 78, 99%) of the prescribed workload (W) was completed with no major adverse events. Improvements were seen in aV̇O2 at ventilatory threshold [7.1 (6.5, 9.1) to 8.5 (7.7, 9.3) mL/kg/min, P = 0.04], work rate at ventilatory threshold [44 (14, 54) to 55 (21, 66) W, P = 0.05], and left ventricular end‐diastolic volume [168 (144, 216) to 159 (124, 212) mL, n = 7, P = 0.02]. HIIT had no effect on maximal oxygen consumption (V̇O2peak) or Kansas City Cardiomyopathy Questionnaire score.ConclusionsCardiopulmonary exercise test‐guided HIIT is feasible and can improve submaximal aerobic capacity in stable patients with chronic LVAD support. Further studies are needed on its effects on the myocardium and its potential role in cardiac rehabilitation programmes.

Right Ventricular Systolic and Diastolic Function as Assessed by Speckle-Tracking Echocardiography Improve with Long-Term Left Ventricular Assist Device Support

Right ventricular (RV) failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. As a LVAD primarily supports the left ventricle, it is unknown whether RV pathology progresses over time leading to deterioration in RV function among patients chronically supported with a LVAD. RV longitudinal strain and strain rate as measured by speckle-tracking echocardiography provide a more sensitive, reproducible, and quantitative assessment of RV systolic and diastolic function than conventional echocardiography. Since LVADs decrease left sided filling pressure, reduce pulmonary pressure, and reduce RV afterload we hypothesized that RV systolic and diastolic function would remain stable or even improve after prolonged continuous-flow LVAD support. Echocardiograms were retrospectively reviewed from before and after implantation of a HeartMate II LVAD between 2006 and 2013 at a single center. Patients who had a baseline echocardiogram before LVAD that was performed off inotropes and a follow up echocardiogram after at least 2 months of LVAD support were included in the analysis. Patients were excluded if they required a RV assist device, had a LVAD malfunction, or had poor echocardiographic visualization of the RV endocardium. The speckle-tracking analysis software Velocity Vector Imaging (Siemens Medical) was used to calculate global RV longitudinal systolic strain, strain rate, and diastolic strain rate. Paired t-tests compared measures at baseline before LVAD to the time of maximal follow up after LVAD implantation. Of the 75 LVAD patients screened, 32 had a baseline echocardiogram off inotropes before LVAD along with a paired echocardiogram at least 2 months after LVAD implantation. 15 patients met exclusion criteria, leaving an analysis cohort of 17 patients with a mean duration of LVAD support at the time of the follow up echocardiogram of 271±129 days. Global RV longitudinal strain improved in 12 of 17 patients (70%) with the average RV strain decreasing from -7.9±2.3% before to -9.8±3.4% after LVAD (p=0.034). Similarly, RV longitudinal systolic strain rate improved in 11 patients (64%) with the average RV systolic strain rate decreasing from -0.67±0.24%/sec before to -0.99±0.35%/sec after LVAD (p=0.002). Finally RV longitudinal diastolic strain rate improved in 14 patients (82%) with the average RV diastolic strain rate increasing from 0.77±0.33%/sec before to 0.99±0.33%/sec after LVAD (p=0.029). Among LVAD patients who did not require a RV assist device, RV systolic and diastolic function as determined by speckle-tracking echocardiography improved in the majority of patients during chronic LVAD support. This suggests that LVADs prevent progression of RV dysfunction in this group of patients and emphasizes the need for strategies for temporary support of the failing RV in the initial period after LVAD implantation to allow for long term stabilization and improvement in RV function.

Superior Mesenteric Artery Mycotic Aneurysm in Patients With Left Ventricular Assist Device Support and Intravenous Drug Abuse

Mycotic aneurysm of the superior mesenteric artery (SMA) is one of the complications associated with infective endocarditis. However, there are no previous case reports in the literature describing mycotic SMA aneurysm after left ventricular assist device (LVAD) implantation. We describe the case of a 31-year-old male diagnosed with congestive heart failure due to nonischemic dilated cardiomyopathy who underwent LVAD implantation for bridge to heart transplantation. The postoperative course was uneventful, and the patient was maintained on anticoagulation and antiplatelet therapy. There were no signs of pump failure or device-related infections. However, 7 months post-LVAD support, the patient complained of abdominal symptoms (nausea and vomiting) with low-grade fever. Computed tomography identified an aneurysmal change of the SMA (2.2 × 1.8 cm). There was no evidence of thrombus or septic vegetation inside the heart. Aneurysm and segmental small bowel resection was performed. Pathological study revealed typical findings of mycotic aneurysm with significant infiltration of inflammatory cells. The patient, however, expired due to concurrent brain hemorrhage. Postmortem study indicated no sign of pump thrombus or septic emboli inside the pump or inflow/outflow conduit. This case report presents a rare mycotic aneurysm that developed in the SMA after chronic LVAD support.

Acquired Aortic Cusp Fusion After Chronic Left Ventricular Assist Device Support

Explanted hearts from patients with chronic left ventricular assist device (LVAD) support have shown the presence of aortic cusp fusion, which results in valvular stenosis and may complicate weaning of a LVAD. This is the first report of aortic cusp fusion diagnosed solely by transesophageal echocardiography (TEE) in vivo in a patient on chronic LVAD support. Under intraoperative TEE guidance, a 41-year-old woman underwent an attempted explantation of a LVAD, which had been implanted 8 months before for dilated cardiomyopathy. When LVAD support was discontinued, previously normal left ventricular function deteriorated, and aortic stenosis from aortic valve cusp fusion was documented by TEE. The explantation procedure was abandoned. This case demonstrates the utility of intraoperative TEE in the evaluation of aortic valvular anatomy and function in patients wtih chronic LVAD support.

Left Ventricular Assist Device Malfunction: An Approach to Diagnosis by Echocardiography

A protocol using transthoracic echocardiography was designed to diagnose the common malfunctions of patients on chronic support with a left ventricular assist device (LVAD). Mechanical circulatory support, primarily with a LVAD, is increasingly used for treatment of advanced heart failure as a bridge to transplant and for long-term treatment of heart failure. The LVAD dysfunction is a recognized complication. To date, no studies have defined the role of transthoracic echocardiography in evaluating long-term mechanical complications of chronic LVAD support. Transthoracic echocardiography was used in a protocol designed to detect the common types of mechanical malfunction. Patients were followed up with serial echocardiograms, and clinical validations were made with findings from a catheter-based protocol and inspection at the time of cardiac transplant or corrective surgery. Thirty-two patients with 44 LVADs were followed up during a four-year period using this protocol that correctly identified 11 patients with inflow valve regurgitation, 2 with intermittent inflow conduit obstruction, 1 with severe kinking of the outflow graft, and 9 with new insufficiency of the native aortic valve. As LVAD use for end-stage heart failure becomes widespread, and durations of support are extended, dysfunction will be increasingly prevalent. Transthoracic echocardiography provides a practical method to accurately identify the causes of mechanical dysfunction with patients on chronic LVAD support.

Left ventricular outflow tract obstruction associated with chronic ventricular assist device support.

Favorable long-term patient outcome after insertion of a left ventricular assist device (LVAD) as a bridge to recovery or destination therapy for the treatment of end-stage cardiomyopathy is adversely affected by pathophysiologic changes affecting the heart. Alterations in the native aortic valve apparatus, specifically aortic valve cusp fusion, is an example of such a phenomenon and may especially affect patients in cases of bridge to recovery, a rare but reported event. A retrospective review of the last 33 LVAD placements at our institution was conducted, including reviews of operative reports and pathologic examinations of the native hearts. Seven hearts were found to have varying degrees of aortic valve cusp fusion after chronic LVAD support (63-1, 339 days). Five of these patients had native aortic valves, and two had bioprosthetic valves. The left ventricular outflow tracts in two patients were surgically occluded at the time of LVAD insertion. Aortic valve cusp fusion occurs in roughly 25% of patients on chronic LVAD support. This phenomenon may prove to be clinically significant by creating a potential source of emboli and infection. In addition, in the case of myocardial recovery, left ventricular outflow tract obstruction could limit parallel flow and produce suprasystemic ventricular pressures that in turn would elevate left ventricular end diastolic pressures. The latter may contribute to further myocardial injury, ultimately limiting the ability of an otherwise recovered heart to be weaned from LVAD support.