Predictors of failure after high urgent listing for a heart transplant

OBJECTIVES

As waiting times for a heart transplant (HTx) increase, the decision of whether a patient should have a high urgent (HU) listing or mechanical circulatory support becomes crucial for further prognosis. The aim of this study was to determine the characteristics that predict failure of an HU listing (death/delisting due to urgent mechanical circulatory support implant or poor clinical condition), the 5-year survival rate, the 1-year post-transplant survival rate and the prognostic accuracy of the cardiac allocation score of patients on the HU list.

METHODS

A total of 447 patients who were on the HU list at our institution between 2005 and 2016 were analysed and stratified according to occurrence of therapy failure or reception of an HTx.

RESULTS

A total of 114 patients suffered from HU listing failure after a median HU time of 31.5 (15-69) days; 320 patients had a primary HTx after a median time of 51.5 (26-90) days on the HU list; 13 patients were excluded from data analysis because of an ongoing HU listing or delisting due to improvement in their haemodynamic condition. In multivariable logistic regression analysis, blood group 0 [odds ratio (OR) 2.48, 95% confidence interval (CI) 1.43-4.3; P = 0.001], INTERMACS Class 1 or 2 (OR 5.1, 95% CI 2.7-9.4; P < 0.001), vasoactive inotropic score (OR 1.18, 95% CI 1.09-1.27; P < 0.001) and brain natriuretic peptide levels (OR 1.00, 95% CI 1.00-1.00; P = 0.001) were identified as independent predictors of HU listing failure. Cardiac allocation score was not independently associated with listing failure. Estimated 5-year and 1-year post-HTx survival rates were similar in the primary HTx group and in patients receiving an HTx after HU therapy failure (P = 0.48 and P = 0.7, respectively).

CONCLUSIONS

INTERMACS levels 1 and 2 and vasoactive inotropic score were the strongest predictors of HU listing failure.

Long-term evaluation of a fully magnetically levitated circulatory support device for advanced heart failure-two-year results from the HeartMate 3 CE Mark Study

AIM

This study aimed to assess safety and outcomes of patients, 2 years after implantation with the HeartMate 3 Left Ventricular Assist System.

METHODS AND RESULTS

This study included 50 adults with New York Heart Association (NYHA) class IIIB or IV symptoms or American College of Cardiology/American Heart Association stage D heart failure with an ejection fraction ≤25% and a cardiac index ≤2.2 L/min/m² without inotropes, or inotrope-dependent with optimal medical management, or listed for heart transplant. The median duration of left ventricular assist device support was 694 days (range: 19-833 days). At baseline, cardiac index was 1.8 ±0.5 L/min/m² , 58% of patients were receiving inotropes, and 92% were INTERMACS profiles 2-4. At 2 years, Kaplan-Meier survival was 74 ±6%, 5 (10%) patients were transplanted, and 32 patients (64%) remain with support. Adverse event rates include bleeding requiring surgery (16%), gastrointestinal bleeding (20%), driveline infection (24%), ischaemic stroke (16%), haemorrhagic stroke (8%), right heart failure (14%), and outflow graft thrombosis (2%). Notably, no haemolysis, pump thrombosis, or pump malfunction events occurred. At 2 years, 47% of patients remained in NYHA class I and 41% in NYHA class II (P <0.0001). From baseline to 2 years, the mean six-minute walk distance increased from 239 m to 347 m (P <0.0001), and the mean EQ-5D quality of life score improved from 48.2 to 70.6 (P < 0.0001).

CONCLUSIONS

Two years post-HeartMate 3 implantation, results show expected and acceptable survival, enhanced haemocompatibility, improved patient functional status and quality of life. This corroborates the success of HeartMate 3 since its first-in-man implantation case in Germany. ClinicalTrials.gov: NCT02170363.

Understanding Left Ventricular Assist Devices

BACKGROUND/AIMS

Long-term mechanical assist devices are now commonly used in the treatment of severe heart failure to unload the failing ventricle, maintain sufficient end-organ perfusion and improve functional capacity. Depending on the assisted ventricles, 3 categories of long-term assist devices are available: left ventricular assist device (LVAD), biventricular assist device and total artificial heart. Improvements in technology, especially the advent of smaller, durable continuous flow pumps, have led to the use of LVADs in a much broader population of patients in the last 10 years. Both the number of patients living with LVADs and the life expectancy of these patients are increasing. Regarding this growing number of patients with LVAD, intensivists need to understand the physiology of the devices, their functioning, potential complications and their management.

METHODS

We performed a narrative review of relevant medical literature regarding the physiology of patients with LVAD and management of common complications relevant to the critical care physicians.

RESULTS

The most frequent complications occurring in the LVAD patients after the post-operative period are bleeding, driveline infections, thrombosis, device malfunction, right ventricular failure and arrhythmias. Bleeding is the most frequent adverse event in LVAD due to a combination of anticoagulation and acquired von Willebrand disease secondary to shear stress produced within the pump. Their management includes antiplatelet therapy arrest, reduction of the anticoagulation regimen and specific therapy if feasible. Infection is the second most common cause of death after cardiac failure in LVAD patients. All infections must be aggressively treated to avoid seeding the device. Device thrombosis can develop even when patients are adequately anticoagulated and taking antiplatelet therapy because the LVAD is responsible for a chronic hypercoagulable state.

CONCLUSION

Management of these unique patients in the ICU is best accomplished with a multidisciplinary team that includes specialists in advanced heart failure, LVAD nurse coordinators and intensivists.

Development and Initial in Vivo Testing of a New Hydraulic Drive System (Paedipump) for Circulatory Support in Infants

The main limitation in the use of circulatory support in children is the lack of an adequate system with regard to size and pumping capacity Recently, two pneumatically driven ventricular support systems with low volume chambers for use in a pediatric population became available. We have developed a hydraulic drive system with an advantageous exact control of the stroke volume. The system enables two different modes of operation: the full-empty and the filled-empty modes. In both cases the ventricle is empty at the end of systole.

This new system was tested in experimental animals (6 pigs, body weight 9.5–14.0 kg) with normal and reduced left ventricular function (MAP<45 mmHg). A 25 ml ventricle (HIA-Medos) was implanted. The full-empty and the filled-empty mode used led to a significant load reduction, both in animals with normal and impaired cardiac function. Plasma lactate levels, pH-values and total body 0 2 consumption were in the normal range during circulatory support indicating adequate organ perfusion.

Results showed that sufficient ventricular support was achieved during all pumping modes due to the possibility of controlling and modifying the stroke volume of the hydraulically driven support system employed according to necessity. This is a promising feature for its future application in infants with congenital or acquired heart diseases.

Initial Results of Clinical Trial with a New Left Ventricular Assist Device (LVAD) Providing Synchronous Pulsatile Flow

Objectives

A multicentric European Clinical Study is ongoing to evaluate safety and efficacy of a new pulsatile implantable LVAD (BestBeat), smaller and lighter than similar devices, capable of providing synchronous and counterpulsating flow with respect to the LV of end-stage heart failure patients. Preliminary clinical results are reported.

Methods

The new BestBeat LVAD was used, consisting of an implantable pulsatile blood pump, electromechanically driven by a ball screw mechanism, and a wearable electronic controller and power sources. The clinical trial was conducted at 5 European centers. Adult patients affected by CHF in NYHA Class IV despite optimized medical treatment were enrolled. The primary study endpoint was survival at 90 days. Further study endpoints were maintenance of adequate LVAD pump flow and a minimum rate of adverse events during support.

Results

As of June 2008, 6 patients received the implant. Cumulative support time was 3.7 years, median support time 176 days. All patients who completed the study survived except for one, who died after 48 days, due to combined infection and cerebrovascular accident. Another two patients died: one from intracranial bleeding 113 days after implant, and one from septic shock after 123 days. Hemodynamic improvement with Cl>2.0 l/min/m2 and recovery of end-organ function expressed by consistent improvement of BUN, creatinine and bilirubin were reached in all patients. No device failure was observed. There was no bleeding requiring re-exploration, no hemolysis and only two device-related infections (both in one patient). Neurologic events were reported, the most serious ones occurring in patients with pre-implant respiratory and kidney failure. Three patients were discharged home. Two patients were successfully transplanted, one after 6 months and one after 13 months on device.

Conclusions

Good performance and efficacy of the device were observed; the endpoints of the study were achieved, and its safety was consistent with expectations. The ongoing study will allow further conclusions to be drawn.

The MiniACcor: Constructive Redesign of an Implantable Total Artificial Heart, Initial Laboratory Testing and Further Steps

The Aachen Total Artificial Heart (ACcor) has been under development at the Helmholtz Institute in Aachen over the last decade. It may serve as a bridge to transplant or as a long-term replacement of the natural heart. Based upon previous in vivo experiments with the ACcor total artificial heart, it was decided to optimize and redesign the pump unit. Smaller dimensions, passive filling and separability into three components were the three main design goals. The new design is called the MiniACcor, which is about 20% smaller than its predecessor, and weighs only 470 grams. Also its external driver/control unit was miniaturized and a new microcontroller was selected. To validate the design, it was extensively tested in laboratory mock loops. The MiniACcor was able to pump between 4.5 and 7 l/min at different pump rates against normal physiological pressures. Several requirements for the future compliance chamber and transcutaneous energy transmission (TET) system were also measured in the same mock loop. Further optimization and validation are being performed in cooperation with the Heart and Diabetes Centre North Rhine-Westphalia.

[Left Ventricular Assist Device Therapy - Ways to Improve the Ambulatory Care]

The use of left-ventricular assist device therapy (LVAD) in terminal heart failure patients is increasing. Many patients are receiving LVAD-therapy as final solution (destination therapy). After discharge from the implanting heart center patient-centered care has to be implemented on an outpatient basis. A responsible ambulatory treatment of this severe heart failure population requires knowledge about LVAD specific problems (general medical care, long term complications, device management). The referring cardiologist as well as the private practitioner should be more involved in the care of patients with LVAD. By this means patients safety would increase and the overall costs decline not at least due to fewer hospital readmissions.

Heartmate 3 fully magnetically levitated left ventricular assist device for the treatment of advanced heart failure -1 year results from the Ce mark trial

Background

The HeartMate 3 Left Ventricular Assist System (LVAS) (St. Jude Medical Inc., St Paul, MN) with full magnetic levitation allows for wide and consistent blood flow paths and an artificial pulse designed for enhanced hemocompatibility. The HeartMate 3 received market approval in the European Union in 2015 following completion of a multicenter study. After reaching the 6-month study endpoint, patients continue to be followed for 2 years with the 1-year results presented herein.

Methods

A prospective, non-randomized study included adults with advanced heart failure and ejection fraction (EF) ≤ 25%, cardiac index (CI) ≤ 2.2 L/min/m2 while not on inotropes, or inotrope dependent, or on optimal medical management for 45/60 days.

Results

Fifty patients—54% bridge to transplant (BTT) and 46% destination therapy (DT)—were enrolled and implanted with the HeartMate 3. At baseline, 92% of the patients were INTERMACS profiles 2–4, with cardiac index 1.8 + 0.5 L/min/m² and 58% were supported with inotropes. At 1 year, 74% of the patients remain on support, 18% expired, 6% transplanted, and 2% explanted. The adverse events include 12% gastrointestinal bleeding, 16% driveline infections, 18% strokes, and 2% outflow graft thrombosis. There was no hemolysis, pump thrombosis or pump malfunction through 1 year. The six-minute walk test distance increased from a mean of 273 m to 371 m (P <0.0001). EQ-5D quality-of-life score increased from a mean of 52.7 to 70.8 (P = 0.0006).

Conclusions

The 1-year HeartMate 3 LVAS results show survival and adverse-event profile are similar to other approved devices, with no pump thrombosis or pump failure. Patient’s functional status and quality of life significantly improved over time.

Trial registration

Clinicaltrials.gov registration number: NCT02170363. Registered June 19, 2014.

Calciotropic and Phosphaturic Hormones in End-Stage Heart Failure Patients Supported by a Left-Ventricular Assist Device

Background

Calcium and phosphate are central for myocardial contractility and energy metabolism, and low levels of the calciotropic hormone 1,25-dihydroxyvitamin D (1,25(OH)₂D), as well as high levels of the phosphaturic hormone fibroblast growth factor (FGF)-23, are independently associated with poor clinical outcome in heart failure (HF) patients. We therefore aimed to investigate the postoperative time course of the aforementioned hormones in HF patients supported with a left-ventricular assist device (LVAD) implant.

Methods

For the present study, stored biobank plasma samples of 69 patients, collected before LVAD implantation (t0) and 12 days (t1), 30 days (t2), 83 days (t3), and 300 days (t4) post-intervention, were used to measure circulating FGF-23, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), 1,25(OH)₂D, and kidney function.

Results

Most patients were male and had baseline INTERMACS levels and cardiac index values ≤ 3 and ≤ 2.7 L/min/m², respectively. There were significant time effects on estimated glomerular filtration rate (eGFR), FGF-23 and 1,25(OH)₂D, but not on PTH or 25OHD. Notably, eGFR values increased and FGF-23 levels decreased only transiently, whereas 1,25(OH)₂D increased continuously until t4. The rise in 1,25(OH)₂D was largely influenced by those patients who survived the first post-implant year, and was not seen in non-survivors. Variations in 1,25(OH)₂D levels could only partly be explained by eGFR values or FGF-23, 25OHD, and PTH levels (multiple R² = 0.305;P<0.001).

Conclusions

The present study indicates that LVAD implantation has only transient effects on circulating FGF-23 levels, but is associated with a continuous increase in circulating 1,25(OH)₂D levels, especially in survivors.

Multicentre clinical trial experience with the HeartMate 3 left ventricular assist device: 30-day outcomes

OBJECTIVES

The objective of this study was to describe the operative experience and 30-day outcomes of patients implanted with the HeartMate 3 Left Ventricular Assist System (LVAS) during the Conformité Européenne (CE) Mark clinical trial.

METHODS

Adult patients met inclusion and exclusion criteria defining advanced-stage heart failure and included the indications of bridge to transplant and destination therapy. Operative parameters, outcomes, adverse events, physical status and quality-of-life parameters were assessed in the first 30 days after LVAS implant.

RESULTS

Fifty patients were implanted with the HeartMate 3 at 10 centres in 6 countries. The 30-day survival rate was 98%. The median operative and cardiopulmonary bypass times were 200 (range: 95-585) min and 84 (range: 47-250) min, respectively. Patients required transfusion with packed red blood cells (3.6 ± 2.3 units), fresh frozen plasma (6.5 ± 5 units) and platelets (2 ± 1 units). Six patients (12%) required reoperation for postoperative bleeding and 10 patients (20%) did not require blood transfusion. The median intensive care time was 6 days (range: 1-112 days) and the total hospital stay was 28 days (range: 14-116 days). The most common adverse events were bleeding (15, 30%), arrhythmia (14, 28%) and infection (10, 20%). There were 2 (4%) strokes.

CONCLUSIONS

The 30-day outcomes following implantation of the HeartMate 3 demonstrates excellent survival with low adverse event rates. The LVAD performed as intended with no haemolysis or device failure.

CLINICALTRIALSGOV IDENTIFIER

NCT02170363. HeartMate 3™ CE Mark Clinical Investigation Plan (HM3 CE Mark).

Fully Magnetically Levitated Left Ventricular Assist System for Treating Advanced HF: A Multicenter Study

BACKGROUND

The HeartMate 3 left ventricular assist system (LVAS) is intended to provide long-term support to patients with advanced heart failure. The centrifugal flow pump is designed for enhanced hemocompatibility by incorporating a magnetically levitated rotor with wide blood-flow paths and an artificial pulse.

OBJECTIVES

The aim of this single-arm, prospective, multicenter study was to evaluate the performance and safety of this LVAS.

METHODS

The primary endpoint was 6-month survival compared with INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support)-derived performance goal. Patients were adults with ejection fraction ≤ 25%, cardiac index ≤ 2.2 l/min/m(2) without inotropes or were inotrope-dependent on optimal medical management, or listed for transplant.

RESULTS

Fifty patients were enrolled at 10 centers. The indications for LVAS support were bridge to transplantation (54%) or destination therapy (46%). At 6 months, 88% of patients continued on support, 4% received transplants, and 8% died. Thirty-day mortality was 2% and 6-month survival 92%, which exceeded the 88% performance goal. Support with the fully magnetically levitated LVAS significantly reduced mortality risk by 66% compared with the Seattle Heart Failure Model-predicted survival of 78% (p = 0.0093). Key adverse events included reoperation for bleeding (14%), driveline infection (10%), gastrointestinal bleeding (8%), and debilitating stroke (modified Rankin Score > 3) (8%). There were no pump exchanges, pump malfunctions, pump thrombosis, or hemolysis events. New York Heart Association classification, 6-min walk test, and quality-of-life scores showed progressive and sustained improvement.

CONCLUSIONS

The results show that the fully magnetically levitated centrifugal-flow chronic LVAS is safe, with high 30-day and 6-month survival rates, a favorable adverse event profile, and improved quality of life and functional status. (HeartMate 3™ CE Mark Clinical Investigation Plan [HM3 CE Mark]; NCT02170363).