Candidate Selection for Long-term Left Ventricular Assist Device Therapy for Refractory Heart Failure

The Efficacy of a Single Session of 20-Minute Mindful Breathing in Reducing Dyspnea Among Patients With Acute Decompensated Heart Failure: A Randomized Controlled Trial

Heart failure is the leading cause of morbidity and mortality worldwide. Standard treatment for heart failure includes pharmacotherapy and cardiac device implants. However, supportive approaches in managing dyspnea in heart failure are limited. This study aimed to test the efficacy of 20-minute mindful breathing in reducing dyspnea among patients admitted for acute decompensated heart failure. We conducted a parallel-group, non-blinded, randomized controlled trial of a single session of 20-minute mindful breathing plus standard care versus standard care alone among patients admitted for moderate to severe dyspnea due to acute decompensated heart failure, using the dyspnea score based on the Edmonton Symptom Assessment System (ESAS), at the Cardiology Unit of University Malaya Medical Centre in Malaysia. Thirty participants were randomly assigned to a single session of 20-minute mindful breathing plus standard care (n = 15) or standard care alone (n = 15), with no difference in their demographic and clinical characteristics. There was statistically significant reduction in dyspnea in the intervention group compared to the control group at minute 20 (U = 49.5, n1 = 15, n2 =15, median reduction in ESAS dyspnea score 1 = 2, median reduction in ESAS dyspnea score 2 = 0, mean rank 1 = 11.30, mean rank 2 = 19.70, z = −2.692, r = 0.4, P = 0.007). Our results provided evidence that a single session of 20-minute mindful breathing was efficacious in reducing dyspnea for patients admitted for acute decompensated heart failure.

Effect of obesity on outcomes in patients undergoing implantation of continuous-flow left ventricular assist devices

The purpose of this study was to analyze the effect of obesity on outcomes after continuous-flow left ventricular assist device (CF-LVAD) implantation. A single-center retrospective analysis was performed on 526 chronic heart failure patients who were implanted with the HeartMate II CF-LVAD (n = 403) or HeartWare HVAD (n = 123) between November 2003 and March 2016. Patients were stratified into 4 groups based on BMI: underweight (< 18.5 kg/m², n = 18, 3.4%), normal-weight (18.5-25 kg/m², n = 173, 32.9%), overweight (25-30 kg/m², n = 182, 30.2%), and obese (> 30 kg/m², n = 153, 33.5%). The underweight group was excluded because of its small sample size. Records were reviewed to determine the incidence of postoperative complications and survival. Survival at 1, 6, 12, and 24 months were similar among normal-weight (91.3, 84.4, 76.3, and 67.6%), overweight (90.4, 80.8, 76.5, and 69.6%), and obese patients (90.7, 74.7, 65.3, and 61.3%, p = 0.24). Additionally, obesity was not a significant predictor of mortality in Cox proportional hazard models (hazard ratio 0.98, 95% confidence interval 0.766-1.277, p = 0.13). These findings suggest that appropriately selected obese patients receive similar survival benefit from CF-LVADs compared to non-obese patients, and obesity should not serve as a contraindication to CF-LVAD implantation.

Prediction of hemodynamics under left ventricular assist device

Left ventricular assist device (LVAD) saves lives in patients with severe left ventricular (LV) failure. However, predicting how much LVAD boosts total cardiac output (CO) remains difficult. This study aimed to develop a framework to quantitatively predict the impact of LVAD on hemodynamics. We adopted the circulatory equilibrium framework and incorporated LVAD into the integrated CO curve to derive the circulatory equilibrium. In anesthetized dogs, we ligated left coronary arteries to create LV failure and inserted a centrifugal pump as LVAD. Using CO and right (PRA) and left atrial pressure (PLA) measured before LVAD support, we predetermined the stressed volume (V) and logarithmic slope of right heart CO curve (SR). Next, we initiated LVAD at maximum level and then decreased LVAD flow stepwise while monitoring hemodynamic changes. We predicted LVAD-induced CO and PRA for given PLA from the predetermined SR and V and compared with those measured experimentally. The predicted CO [ r2 = 0.907, SE of estimate (SEE) = 5.59 ml·min−1·kg−1, P < 0.001] and PRA ( r2 = 0.967, SEE = 0.307 mmHg, P < 0.001) matched well with measured values indicating the validity of the proposed framework. We further conducted simulation using the validated framework to analyze the impact of LVAD on PRA under various right ventricular (RV) functions. It indicated that PRA is relatively insensitive to changes in RV end-systolic elastance or pulmonary arterial resistance, but sensitive to changes in V. In conclusion, the circulatory equilibrium framework predicts quantitatively the hemodynamic impact of LVAD. This knowledge would contribute to safe management of patients with LV failure undergoing LVAD implantation.

NEW & NOTEWORTHY Hemodynamic response to left ventricular assist device (LVAD) has not been quantitatively investigated. This is the first report of quantitative prediction of the hemodynamics on LVAD using circulatory equilibrium framework. The validated framework allows us to simulate the impact of LVAD on right atrial pressure under various right ventricular functions.

Usefulness of Psoas Muscle Area Determined by Computed Tomography to Predict Mortality or Prolonged Length of Hospital Stay in Patients Undergoing Left Ventricular Assist Device Implantation

The purpose of this study is to examine the association of sarcopenia as measured by psoas muscle area and outcomes in patients undergoing left ventricular assist device (LVAD) implantation. We retrospectively examined 333 consecutive patients who underwent implantation of a HeartMate II LVAD at our institution from June 2008 to August 2013. Patients were included if they had a perioperative computed tomography that spanned the L3-L4 vertebrae. Sarcopenia was defined as having the lowest tertile psoas muscle area by gender. The primary end point was the composite of inpatient death or prolonged length of stay of >30 days. One hundred patients met inclusion criteria. The psoas muscle area cut-off values for the lowest tertiles were 12.0 cm² for men and 6.5 cm² for women, resulting in 32 sarcopenic patients (32%). The primary outcome of inpatient death or prolonged length of stay occurred in 81% of patients in the sarcopenic versus 60% in the nonsarcopenic group (p = 0.043). There was a trend toward prolonged length of stay in sarcopenic patients but no difference in overall mortality. This demonstrates that sarcopenia as measured by psoas muscle area is associated with increased composite length of stay and mortality after LVAD implantation and may serve as correlate for frailty.

Effects of Sevoflurane and Propofol on Organ Blood Flow in Left Ventricular Assist Devices in Pigs

The aim of this study was to assess the effect of sevoflurane and propofol on organ blood flow in a porcine model with a left ventricular assist device (LVAD). Ten healthy minipigs were divided into 2 groups (5 per group) according to the anesthetic received (sevoflurane or propofol). A Biomedicus centrifugal pump was implanted. Organ blood flow (measured using colored microspheres), markers of tissue injury, and hemodynamic parameters were assessed at baseline (pump off) and after 30 minutes of partial support. Blood flow was significantly higher in the brain (both frontal lobes), heart (both ventricles), and liver after 30 minutes in the sevoflurane group, although no significant differences were recorded for the lung, kidney, or ileum. Serum levels of alanine aminotransferase and total bilirubin were significantly higher after 30 minutes in the propofol group, although no significant differences were detected between the groups for other parameters of liver function, kidney function, or lactic acid levels. The hemodynamic parameters were similar in both groups. We demonstrated that, compared with propofol, sevoflurane increases blood flow in the brain, liver, and heart after implantation of an LVAD under conditions of partial support.

Inhaled Milrinone After Left Ventricular Assist Device Implantation

BACKGROUND

Proven strategies to reduce right ventricular (RV) dysfunction after continuous-flow left ventricular assist device (CF-LVAD) implantation are lacking. We sought to evaluate the tolerability, feasibility, efficacy, and pharmacokinetics of inhaled milrinone (iMil) delivery after CF-LVAD implantation.

METHODS AND RESULTS

We prospectively evaluated fixed-dose nebulized iMil delivered into a ventilator circuit for 24 hours in 10 postoperative CF-LVAD (Heartmate-II) patients. Tolerability (arrhythmias, hypotension, and hypersensitivity reaction), efficacy (hemodynamics), pharmacokinetics (plasma milrinone levels), and cost data were collected.Mean age was 56 ± 9 years, 90% were male, and mean INTERMACS profile was 2.5 ± 0.8. No new atrial arrhythmia events occurred, although 3 (30%) ventricular tachycardia (1 nonsustained, 2 sustained) events occurred. Sustained hypotension, drug hypersensitivity, death, or need for right ventricular assist device were not observed. Invasive mean pulmonary arterial pressure from baseline to during iMil therapy was improved (P = .017). Mean plasma milrinone levels (ng/mL) at baseline, and 1, 4, 8, 12, and 24 hours were 74.2 ± 35.4, 111.3 ± 70.9, 135.9 ± 41.5, 205.0 ± 86.7, 176.8 ± 61.3 187.6 ± 105.5, respectively. Reduced institutional cost was observed when iMil was compared with nitric oxide therapy over 24 hours ($165.29 vs $1,944.00, respectively).

CONCLUSIONS

iMil delivery after CF-LVAD implantation was well tolerated, feasible, and demonstrated favorable hemodynamic, pharmacokinetic, and cost profiles. iMil therapy warrants further study in larger clinical trials.

Preparedness planning before mechanical circulatory support: a "how-to" guide for palliative medicine clinicians

The role of palliative medicine in the care of patients with advanced heart failure, including those who receive mechanical circulatory support, has grown dramatically in the last decade. Previous literature has suggested that palliative medicine providers are well poised to assist cardiologists, cardiothoracic surgeons, and the multidisciplinary cardiovascular team with promotion of informed consent and initial and iterative discussions regarding goals of care. Although preparedness planning has been described previously, the actual methods that can be used to complete a preparedness plan have not been well defined. Herein, we outline several key aspects of this approach and detail strategies for engaging patients who are receiving mechanical circulatory support in preparedness planning.

Our experience with implantation of VentrAssist left ventricular assist device

Perioperative anaesthetic management of the VentrAssist™ left ventricular assist device (LVAD) is a challenge for anaesthesiologists because patients presenting for this operation have long-standing cardiac failure and often have associated hepatic and renal impairment, which may significantly alter the pharmacokinetics of administered drugs and render the patients coagulopathic. The VentrAssist is implanted by midline sternotomy. A brief period of cardiopulmonary bypass (CPB) for apical cannulation of left ventricle is needed. The centrifugal pump, which produces non-pulsatile, continuous flow, is positioned in the left sub-diaphragmatic pocket. This LVAD is preload dependent and afterload sensitive. Transoesophageal echocardiography is an essential tool to rule out contraindications and to ensure proper inflow cannula position, and following the implantation of LVAD, to ensure right ventricular (RV) function. The anaesthesiologist should be prepared to manage cardiac decompensation and acute desaturation before initiation of CPB, as well as RV failure and severe coagulopathic bleeding after CPB. Three patients had undergone implantation of VentrAssist in our hospital. This pump provides flow of 5 l/min depending on preload, afterload and pump speed. All the patients were discharged after an average of 30 days. There was no perioperative mortality.

Long-term continuous flow left ventricular assist device support and end-organ function: prospects for destination therapy

Pulsatile flow left ventricular assist devices (PF-LVADs) have successfully supported patients with severe heart failure for bridge-to-transplant (BTT) and destination therapy (DT). End-organ dysfunction is often reversed, optimizing the patient's condition to enhance survival, and quality of life. Questions have been raised regarding the potential for continuous flow LVADs (CF-LVADs) to provide the same quality of circulatory support. Prior research showing that PF is superior to continuous, non-PF does not appear to be relevant with CF-LVADs for BTT and DT. Under most clinical conditions, arterial pulsatility is present during CF-LVAD support, and this type of support should not be termed "nonpulsatile." Clinical studies have shown that renal, hepatic, and neurocognitive function is either maintained within a normal range, or is significantly improved, during CF-LVAD support for durations up to 15 months. Results of the randomized clinical trial between the CF HeartMate II and the pulsatile HeartMate XVE (both by Thoratec Corp, Pleasanton, CA, USA) are pending final US Food and Drug Administration (FDA) review and are not yet published. Studies of microcirculation during CF-LVAD support indicate that capillary blood flow is adequate to support cellular function. There are anecdotal cases of patients being supported with a CF-LVAD for over seven years with preserved end-organ function. Presently, there are no clinical reports indicating that end-organ function is not well maintained. Current clinical evidence indicates that end-organ perfusion and function can be well maintained for extended durations of support with a CF-LVAD.

Contemporary use of ventricular assist devices

The introduction of the heart lung machine more than 50 years ago proved in principle that heart function can be replaced, albeit for short periods. This was followed by attempts to produce total or partial artificial hearts that could function for prolonged periods of time. Progress in this field has been intermittent but has accelerated considerably in the past 10 years, with ventricular assist devices (VADs) reaching an impressive degree of sophistication and complexity owing to the contributions from clinicians, engineers, scientists, industrialists, and others. This review describes the currently available types of VADs, their current clinical use, the patient selection process, the trend toward use of VADs in patients with less severe heart failure, and the use of VADs for myocardial recovery in combination with novel pharmacological strategies, gene therapy, and cell therapy.

Role of a percutaneous ventricular assist device in decision making for a cardiac transplant program

BACKGROUND

The role of a percutaneous ventricular assist device (VAD) for left heart support in the management of patients in cardiogenic shock is not well defined.

METHODS

All patients who received LV support using the percutaneous TandemHeart (percTH) ventricular support device (Cardiac Assist, Pittsburgh, PA) were retrospectively reviewed. Indications for insertion included bridge to decision (BTD) or "salvage" and bridge to transplant (BTT).

RESULTS

Between April 2005 and December 2008, 22 percTH devices were successfully implanted in patients (13 men) with isolated left heart failure. Mean duration of support was 6.8 +/- 9.4 days (median, 4; maximum, 45 days). Of patients requiring percTH support for at least 3 days, mean pump flows were 3.77 +/- 1.10, 4.22 +/- 0.69, and 4.04 +/- 0.41 L/min on at days 1, 2, and 3. Mean serum aspartate aminotransferase levels were 455 +/- 994 mg/dL before percTH, 551 +/- 1046 mg/dL at day 1, and 231 +/- 225 mg/dL at day 3 after percTH. No mechanical device failure, device-related infections, or cerebrovascular accidents occurred. Ten of 11 BTT patients were successfully bridged. Support was withdrawn in 7 of 11 BTD patients. The percTHs were successfully explanted in 4 BTD patients: 1 as recovery, 1 direct to transplant, and 2 to VAD.

CONCLUSIONS

The percTH was reliable, with no mechanical device failures and minimal associated adverse events. We support the use of the percTH in the BTD mode, allowing time for a more complete evaluation of neurologic and end-organ status without the added expense and morbidity of a long-term VAD.

Management of end-stage heart failure: a perspective on the Arab Gulf states

The ever expanding epidemic of end-stage heart failure represents one of the greatest challenges of modern cardiovascular medicine. With medical treatments hampered by significant limitations, physicians caring for patients with advanced heart disease have turned to cardiac transplantation and durable mechanical circulatory assist devices as definitive therapies. These advanced therapeutic modalities are not widely available outside the United States and Europe, but nevertheless offer enormous potential for patients in the Arab Gulf suffering from end-stage heart failure. This review will discuss the management of end-stage heart failure in the Gulf States, with an emphasis on therapies best utilized within a framework of regional cooperation and coordination.

Renal function and outcome after continuous flow left ventricular assist device implantation

BACKGROUND

Renal dysfunction as a risk factor with the use of left ventricular assist devices (LVAD) is controversial. We determined the effect of renal function on outcomes after continuous flow LVAD implantation.

METHODS

Eighty-six patients with advanced heart failure undergoing continuous flow LVAD implantation as bridge to transplantation from November 1998 to July 2007 were retrospectively analyzed. Renal function was assessed using the Modification of Diet in Renal Disease study-derived glomerular filtration rates (GFR [mL x min(-1) x 1.73 m(-2)]). Patients were categorized into two groups based on pre-LVAD GFR: those with normal renal function (GFR > 60, n = 46), and those with renal dysfunction (GFR < 60, n = 40).

RESULTS

Post-LVAD survival at 1, 3, and 6 months for GFR greater than 60 was 91.3%, 79.9%, 72.6%, respectively, and for GFR less than 60, it was 92.5%, 66.5%, 47.9%, respectively (p = 0.038). Bridge-to-transplant rate was lower for GFR less than 60 than for GFR greater than 60 (40.0% versus 63.0%, p = 0.033). For GFR less than 60, GFR improved on LVAD support: implant to month 6, 41.7 +/- 11.5 to 62.7 +/- 25.0 (p = 0.021). Post-LVAD survival was improved in GFR less than 60 patients who after LVAD implantation recovered renal function to GFR greater than 60 (p < 0.001). Patients with post-LVAD renal failure had significantly lower post-LVAD survival regardless of pre-LVAD renal function (p < 0.001).

CONCLUSIONS

Patients with renal dysfunction have poorer outcomes after continuous flow LVAD implantation. However, renal function improves after LVAD implantation and is associated with improved survival. Our data underscore the importance of end-organ function in patient selection for LVAD therapy.

Destination therapy: current results and future promise

The landmark Randomized Evaluation of Mechanical Assistance in the Treatment of Congestive Heart Failure (REMATCH) trial demonstrated that the implantation of left ventricular assist devices (LVADs) as an alternative to heart transplantation, or destination therapy (DT) is superior to any known medical therapy in patients with end-stage heart failure who are not eligible for transplantation. In this article, we review results of the first United States and European clinical trials of DT, including the REMATCH, the Investigation of the Non-Transplant Eligible Patients who are Inotrope Dependent (INTREPID), and the Clinical Utility Baseline Study (CUBS) trials, as well as the outcomes of the first DT implantations in the post-REMATCH era in the United States. The article summarizes the current state of knowledge and future directions in the field of permanent mechanical circulatory support therapy as an alternative to heart transplantation.

Initial clinical experience with the VentrAssist left ventricular assist device: the pilot trial

BACKGROUND

The VentrAssist (VA) is a novel, continuous flow left ventricular assist device (LVAD). The purpose of this trial was to investigate the safety and efficacy of the VA in elderly patients with end-stage heart failure.

METHODS

In this prospective trial, patients requiring circulatory support either as destination therapy (DT) or as a bridge to transplant (BTT) were implanted with a VA device.

RESULTS

Between June 2003 and August 2006, 9 elderly patients (mean age 65 years) were implanted. The median support time was 454 (range 73 to 977) days for the DT and 35 (range 26 to 508) days for the BTT cohort. All patients survived implantation; 30-day mortality was 22% (n = 2). The adverse event profile was encouraging, with no embolic neurologic events and minimal sepsis. Cumulative trial support time was 7.3 patient-years.

CONCLUSIONS

The VentrAssist shows promise as a safe and reliable "third-generation" VAD. Having demonstrated potential as a DT and prolonged BTT device, extended clinical trials are warranted.

Destination nowhere: a potential dilemma with ventricular assist devices

Increasingly, ventricular assist devices (VADs) are used as destination therapy for those who are not candidates for heart transplantation. Although these devices can benefit patients by improving their functional status and quality of life, they can, in some cases, facilitate an end-point known as "destination nowhere." In such situations, patients and clinicians find themselves in medical limbo where the patient's net benefit is, in fact, a burden, or the continued use of the device has no utility in light of the goals of the technology. This article presents guidance for avoiding "destination nowhere," as well as guidance for ethical care when patients arrive at this juncture.

Mechanical circulatory support devices for acute heart failure syndromes: considerations for clinical trial design

Mechanical circulatory support (MCS) devices are a guideline-recommended treatment option for a small subset of advanced heart failure patients. MCS has the potential to become more prominent in the management of Acute Heart Failure Syndromes (AHFS) as device technology advances and as clinical trials consistently discover neutral or harmful effects with pharmacologic therapies hypothesized to be beneficial in this population. While it is now possible to identify AHFS patients who are at high risk of death, the therapeutic options available to improve their long-term outcomes are limited. MCS therapy in this population offers a "bridge to recovery" strategy; these patients may have viable myocardium that responds favorably to the influence of MCS on neurohormones, cytokines, and/or reverse remodeling. Patients at high risk for mortality who have a substantial likelihood of benefiting from MCS can be easily identified using standard clinical criteria developed from large observational databases. MCS technology is rapidly evolving, and risks related to implantation are declining. It is evident that rigorous clinical trial testing of the potential risks, benefits, and economic implications of MCS in patients with AHFS will need to be conducted before the "routine" application of this aggressive therapy. This paper examines the rationale for conducting trials of MCS devices in patients with AHFS, and it explores considerations for patient selection and appropriate endpoints. This manuscript was generated from discussions on this issue during the third international meeting of the International Working Group on AHFS held in Washington, DC, April 8-9, 2006.

The financial burden of destination left ventricular assist device therapy: who and when?

Heart failure continues to be an economic health care burden of profound proportion. The disease in its end stage has limited therapeutic options. Transplantation is limited by the number of available organs. Mechanical assist therapy has continued to be an increasingly feasible strategy for bridging patients to heart transplantation but is also now used in place of transplantation. The REMATCH trial was the first trial to document the failure of medical therapy in end-stage heart failure when compared with mechanical support. However, one of the primary concerns is the marked expense involved with this invasive therapy. As the cost of ventricular assist devices (VADs) for destination therapy has been appraised in the medical literature, and through examination of patients who have been implanted in the "post-REMATCH era," a subset of patients has emerged in whom VAD implantation is futile, as well as another subset that clearly benefits both in quality of life as well as in mortality. We review the current literature on VAD feasibility for destination therapy as well as ongoing trends in careful patient selection to improve outcomes and, implicitly, cost benefit of VAD therapy.

Utilization of Acoustic Signatures to Identify HeartMate XVE Device End-of-Life

BACKGROUND

As outcomes for destination therapy continue to improve, many patients are requiring left ventricular assist device (LVAD) exchange due to end-of-life of their LVAD. Current techniques to identify and diagnose device end-of-life issues usually require invasive testing or off-site filter dust analysis. In this study we assess a non-invasive technique using acoustic signals generated from the HeartMate XVE LVAD to potentially identify impending device end-of-life issues.

METHODS

Nine patients were prospectively followed after implantation of the HeartMate XVE LVAD as destination therapy between May 2004 and July 2006. Acoustic signals were collected using an aquatic hydrophone system interfaced with a data acquisition system and a standard laptop computer. Data were collected at pre-set intervals. All data/acoustic signals were prospectively interpreted by a blinded independent reviewer skilled at interpreting acoustic signals. Acoustic data suggesting possible device failure were then correlated with clinical findings and LVAD examination at the time of device removal.

RESULTS

All patients survived long enough to develop signs of impending device end-of-life. Four of 9 (44%) patients developed inflow valve incompetence, 4 (44%) were identified as having significant bearing wear, and 1 (12%) had both. All acoustically identified device issues were confirmed by standard clinical examinations and testing (echocardiography, angiography, laboratory tests and filter dust analysis). The acoustic findings were subsequently confirmed at time of device exchange. All patients ultimately had their device successfully exchanged and have continued to live with their new apparatus.

CONCLUSIONS

Acoustic signal monitoring can successfully identify HeartMate XVE device end-of-life. This new method provides a low-cost, reproducible, non-invasive technique that may be used to identify possible impending device failure.

A Novel Mechanical Circulatory Approach for Patients with Cardiogenic Shock in the Intensive Care Unit

BACKGROUND

The capacity of the heart to maintain cardiac output can be acutely impaired as a result of myocardial infarction, graft failure after transplantation, or other cardiac events. Medical therapy or the use of an intra-aortic balloon pump may be insufficient to help the patient overcome acute cardiogenic shock. The set-up of mechanical assist devices such as extracorporeal membrane oxygenation or patient relocation into the operating room requires valuable time that is often not available. The aim of our study was to test whether a novel left ventricular assist device can be percutaneously implanted without fluoroscopy under echocardiographic navigation in a preclinical model.

METHODS

Pigs were subjected to percutaneous implantation of a novel left ventricular assist device under navigation of transesophageal echocardiography (TEE) without fluoroscopic support. Percutaneous puncture of the interatrial septum using a Brockenbrough needle and insertion of the afferent cannula into the femoral vein and its advance to the right atrium and through the interatrial septum into the left atrium was performed under echocardiographic control. The efferent cannula was inserted into the contralateral femoral artery using the Seldinger technique.

RESULTS

In all animals, the percutaneous implantation of a left ventricular assist device was successful under only TEE navigation.

CONCLUSIONS

The ability to abstain from fluoroscopy and the feasibility of inserting the afferent cannula across the interatrial septum guided by TEE allows for application of this system in intensive care units, saving precious time as well as financial and human resources.