Algorithms to guide ambulance clinicians in the management of emergencies in patients with implanted rotary left ventricular assist devices

Advances in left ventricular assist device (LVAD) therapy have resulted in increasing numbers of adult LVAD recipients in the community. However, device failure, stroke, bleeding, LVAD thrombosis and systemic infection can be life-threatening emergencies. Currently, four LVAD systems are implanted in six UK transplant centres, each of which provides device-specific information to local emergency services. This has resulted in inconsistent availability and content of information with the risks of delayed or inappropriate decision-making. In order to improve patient safety, a consortium of UK healthcare professionals with expertise in LVADs developed universally applicable prehospital emergency algorithms. Guidance was framed as closely as possible on the standard ABCDE approach to the assessment of critically ill patients.

Comparison of paracorporeal and continuous flow ventricular assist devices in children: preliminary results

Objectives

With the scarcity of organs, a durable, reliable ventricular assist device (VAD) is required. The Berlin Heart EXCOR ® (BH) remains the most established VAD in the paediatric population. Implantable continuous flow (CF) VADs have been introduced to the paediatric field with encouraging early results. In this study, we compared the results of a newly introduced CF VAD (HeartWare VAD [HVAD] ® ) to results in a matched group of BH recipients.

Methods

The study included patients aged <16 years who received mechanical left VAD (LVAD) support between December 2005 and January 2016. The preimplant characteristics and postimplant outcomes of patients who received the HVAD were compared with those of a matched group who received the BH. Patients with congenital heart disease were excluded.

Results

Thirty patients were included in the study: 13 had received the HVAD and were matched with 17 patients who had received the BH LVAD. The only difference in preimplant characteristics was the need for higher inotropic support in the BH group. There was no difference in the need for right ventricular (RV) support (58.8% for BH vs 53.8% for HVAD, P  = 1.00) or in the incidence of cerebrovascular accidents (12.5% vs 7.7%, respectively, P  = 1.00), though the BH group showed prolonged mechanical ventilation (31.3% vs 0%, P  = 0.047). There were no deaths while on VAD support in either group. Patients with the HVAD showed a bimodal distribution for the primary end point (transplant/explant): All HVAD recipients who also required early RV support reached this end point within 30 days of receiving the implant.

Conclusions

Our early experience with the CF intracorporeal LVAD system (HVAD) indicates outcomes comparable to those with the well-established pulsatile flow paracorporeal LVAD (BH). The theoretical durability of the CF device, which might also allow for the possibility of hospital discharge and better quality of life, is yet to be proven.

Preexisting cognitive impairment in intracerebral hemorrhage

OBJECTIVES

Preexisting cognitive impairment is a predictor of cognitive decline after ischemic stroke, but evidence in intracerebral hemorrhage (ICH) is limited. We aimed to determine the prevalence of premorbid cognitive impairment in patients with ICH.

MATERIALS AND METHODS

We included patients with acute ICH. Pre-ICH cognitive impairment was determined based on the results of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) that uses information from close relatives. Patients were assessed as having been cognitively impaired with an IQCODE score of ≥3.44; an IQCODE ≥4.00 indicated pre-ICH dementia. CT and MRI images were reviewed to determine the extent of white matter lesions and to measure the radial width of the temporal horn as marker of brain atrophy. We investigated differences of cardiovascular risk factors and imaging data between patients with and without pre-ICH cognitive impairment using correlation analyses, uni- and multivariable regression models. Functional neurological state was assessed using the modified Rankin Scale (mRS). The mRS was dichotomized at the level of 3, and a premorbid mRS of 0-2 was considered as functional independency.

RESULTS

Among the 89 participants, median age was 70 years (interquartile range 58-78) and 52 (58.4%) were male. IQCODE indicated pre-ICH cognitive impairment in 18.0% (16 of 89), and 83.1% were functionally independent before ICH. Cognitive impairment was associated with a premorbid mRS≥3 (chi squared test, P=0.009). In multivariable analysis, prior stroke/transient ischemic attack (OR 18.29, 95%-CI 1.945-172.033, P=.011) and hematoma volume (OR 0.90, 95%-CI 0.812-0.991, P=.033) were independently associated with pre-ICH cognitive impairment.

CONCLUSIONS

In conclusion, cognitive impairment frequently precedes ICH. A higher frequency of cerebrovascular events suggests a role of vascular processes in the development of cognitive impairment before ICH.

Left Ventricular Assist Device as a Bridge to Recovery for Patients With Advanced Heart Failure

BACKGROUND

Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery.

OBJECTIVES

This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls.

METHODS

Fifty-eight male patients-18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)-and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data. Cardiac function was represented by peak exercise cardiac power output (mean arterial blood pressure × cardiac output) and functional capacity by peak exercise O₂ consumption.

RESULTS

All patients demonstrated a significant exertional effort as demonstrated with the mean peak exercise respiratory exchange ratio >1.10. Peak exercise cardiac power output was significantly higher in healthy controls and explanted LVAD patients compared with other patients (healthy 5.35 ± 0.95 W; explanted 3.45 ± 0.72 W; LVAD implanted 2.37 ± 0.68 W; and HTx 1.31 ± 0.31 W; p < 0.05), as was peak O₂ consumption (healthy 36.4 ± 10.3 ml/kg/min; explanted 29.8 ± 5.9 ml/kg/min; implanted 20.5 ± 4.3 ml/kg/min; and HTx 12.0 ± 2.2 ml/kg/min; p < 0.05). In the LVAD explanted group, 38% of the patients achieved peak cardiac power output and 69% achieved peak O₂ consumption within the ranges of healthy controls.

CONCLUSIONS

The authors have shown that a substantial number of patients who recovered sufficiently to allow explantation of their LVAD can even achieve cardiac and physical functional capacities nearly equivalent to those of healthy controls.

Evaluation of the HeartWare ventricular assist device Lavare cycle in a particle image velocimetry model and in clinical practice

OBJECTIVES

Ventricular blood stasis is a concern for continuous flow mechanical support devices and might contribute to the formation of thromboembolic events. The HeartWare® Ventricular Assist System (HVAD®) is equipped with the Lavare™ cycle that is a periodic speed modulation feature designed to alter flow patterns within the left ventricle and reduce areas of potential blood stasis. Here, we report in vitro and clinical findings on the effects of the Lavare cycle.

METHODS

The effect of pump speed changes on the intraventricular flow field was examined with an in vitro particle image velocimetry model. The clinical impact of the Lavare cycle was evaluated through a retrospective review of the ReVOLVE study which includes 248 patients implanted with the HVAD following Conformité Européenne Mark in nine centres in Europe and Australia. Baseline characteristics, adverse event profiles and Kaplan-Meier survival estimates were stratified by patients using/not using the Lavare cycle.

RESULTS

Particle image velocimetry showed increased ventricular washout with an active Lavare cycle as measured by the fluid velocities and angular dispersion parameters. With the Lavare cycle on, there was also a 22% decrease in the stagnation index compared with when the Lavare cycle was off. In the ReVOLVE registry, patients with the Lavare cycle turned on (n = 215) were supported for 497 patient-years, whereas patients who did not use the speed modulation (n = 33) were supported for 39.3 patient-years. The Lavare cycle did not significantly affect patient survival as both groups had approximately an 80% survival after 1 year. Patients using the Lavare cycle had significantly fewer rates of stroke [0.06 vs 0.20 events per patient-year (EPPY), P = 0.0008], sepsis (0.03 vs 0.15 EPPY, P = 0.0003) and right heart failure (0.03 vs 0.18 EPPY, P < 0.0001) with no difference in the transplant or recovery rates among the two cohorts.

CONCLUSIONS

The Lavare cycle effectively generates ventricular washout and the adverse event profiles of ReVOLVE patients with the Lavare cycle on were better than those with the Lavare cycle off. Larger studies are warranted to verify the positive effect of the Lavare cycle and to optimize speed modulation settings, so additional clinically relevant improvements can be realized.

An Extended Role of Continuous Flow Device in Pediatric Mechanical Circulatory Support

BACKGROUND

Mechanical circulatory support in the pediatric population is currently limited to pulsatile ventricular assist devices (VAD). In recent years, the use of durable, newer generation, continuous flow devices have increased substantially among adults with end-stage heart failure. We examined the extended role of this device in the pediatric population (aged less than 18 years).

METHODS

Between 2010 and 2015, 12 patients (median age 7.1 years; range, 3.7 to 17.0; one third of patients were aged 5 years or less) received a HeartWare ventricular assist device (HVAD; HeartWare, Framingham, MA), 11 for cardiomyopathy and 1 for posttransplant rejection. Right VAD support (n = 5; 42%) was provided by a short-term device (Levitronix, Zurich, Switzerland).

RESULTS

Overall, 1 patient died (day 638), 8 patients (67%) underwent transplantation, 1 patient (8.3%) recovered, and 2 patients (17%) remain on HVAD. The mean length of support was 150 days (range, 16 to 638). Four patients (33.3%) were discharged home (all left VAD). In the left VAD group (n = 7), 3 patients subsequently received transplants (days 185, 201, and 234, respectively), 1 recovered (day 149), 1 died (day 638), 1 remained on HVAD (day 198), and 1 needed conversion to biventricular assist device (BIVAD [day 73]). In the BIVAD group (n = 5), right VAD was weaned in 3 (60%), all subsequently received transplants, and 2 remained on BIVAD support until transplant (days 16 and 17, respectively). One BIVAD patient required conversion to central cannulation for longer-term support. Four BIVAD patients (80%) were in Interagency Registry for Mechanically Assisted Circulatory Support level 1 before VAD compared with 2 (29%) in the left VAD group (p = not significant). The actuarial survival rate was 100% at 1 year with no neurologic events.

CONCLUSIONS

The third-generation, continuous flow device can provide durable support in the pediatric population. The selection strategy for patients who benefit most from the device continues to evolve. It is anticipated that a smaller design in the future will benefit an even wider pediatric population with heart failure.

Proposal for a revised definition of dilated cardiomyopathy, hypokinetic non-dilated cardiomyopathy, and its implications for clinical practice: a position statement of the ESC working group on myocardial and pericardial diseases

In this paper the Working Group on Myocardial and Pericardial Disease proposes a revised definition of dilated cardiomyopathy (DCM) in an attempt to bridge the gap between our recent understanding of the disease spectrum and its clinical presentation in relatives, which is key for early diagnosis and the institution of potential preventative measures. We also provide practical hints to identify subsets of the DCM syndrome where aetiology directed management has great clinical relevance.

Considerations for patients awaiting heart transplantation-Insights from the UK experience

The nature and size of the heart transplant waiting list has changed over recent years, most obviously with a larger number of patients on the list with ventricular assist devices (VADs). Given the limited numbers of available donors it is time to re-evaluate who is actually placed on the list. Evidence suggests that many patients with stable ambulatory heart failure might have a limited survival benefit from heart transplantation, so these patients may be an obvious target when considering how to reduce the size of the list. How stable VAD patients or adult congenital heart disease patients with declining symptoms should be prioritized for transplantation is unclear. Nevertheless we do need effective and simple models that can predict which of these disparate groups would benefit from transplantation so that we can fairly distribute this scarce commodity to the sickest patients that would benefit the most from transplantation.

Effect of left ventricular assist device implantation and heart transplantation on habitual physical activity and quality of life

The present study defined the short- and long-term effects of left ventricular assist device (LVAD) implantation and heart transplantation (HT) on physical activity and quality of life (QoL). Forty patients (LVAD, n = 14; HT, n = 12; and heart failure [HF], n = 14) and 14 matched healthy subjects were assessed for physical activity, energy expenditure, and QoL. The LVAD and HT groups were assessed postoperatively at 4 to 6 weeks (baseline) and 3, 6, and 12 months. At baseline, LVAD, HT, and HF patients demonstrated low physical activity, reaching only 15%, 28%, and 51% of that of healthy subjects (1,603 ± 302 vs 3,036 ± 439 vs 5,490 ± 1,058 vs 10,756 ± 568 steps/day, respectively, p <0.01). This was associated with reduced energy expenditure and increased sedentary time (p <0.01). Baseline QoL was not different among LVAD, HT, and HF groups (p = 0.44). LVAD implantation and HT significantly increased daily physical activity by 60% and 52%, respectively, from baseline to 3 months (p <0.05), but the level of activity remained unchanged at 3, 6, and 12 months. The QoL improved from baseline to 3 months in LVAD implantation and HT groups (p <0.01) but remained unchanged afterward. At any time point, HT demonstrated higher activity level than LVAD implantation (p <0.05), and this was associated with better QoL. In contrast, physical activity and QoL decreased at 12 months in patients with HF (p <0.05). In conclusion, patients in LVAD and HT patients demonstrate improved physical activity and QoL within the first 3 months after surgery, but physical activity and QoL remain unchanged afterward and well below that of healthy subjects. Strategies targeting low levels of physical activity should now be explored to improve recovery of these patients.

Four-year outcomes with third-generation centrifugal left ventricular assist devices in an era of restricted transplantation

OBJECTIVES

Third-generation ventricular assist devices (VADs) are associated with improved outcomes, though in recent clinical trials bridge-to-transplant (BTT) rates are ∼30% at 6 months, so that transplantation can be used as a ‘bail out’ for serious complications. In the UK, there was a significant reduction in heart transplantation rates over the last decade, so that transplantation from VADs is much less frequent. The objective of this study was to determine outcomes and their predictors in this situation of low BTT rates, and as patients were exposed to long-term support, the incidence and outcomes of VAD thrombosis.

METHODS

We analysed outcomes for 102 consecutive patients between 2009 and 2013 (mean age 47 ± 13; VentrAssist n = 6 and HeartWare n = 96). The median duration of support was 462 ± 426 days.

RESULTS

Survival rates on the device were 75 and 66% at 1 and 2 years, respectively. Older age and more acute INTERMACS groups were significantly related to reduced survival within the first 90 days (P = 0.030 and 0.010, respectively). Poor preoperative right ventricular (RV) function had a negative effect on survival after 1 year (P = 0.009), though not earlier. VAD thrombosis (n = 24 HeartWare and n = 1 VentrAssist) occurred at 0.18 events per patient-year for HeartWare and 0.07 for VentrAssist devices at a median time of onset at 404 ± 281 days. There was no significant effect of VAD thrombosis on survival. Only 14 of 102 patients were transplanted at a median of 334 ± 347 days, and only 3 were transplanted within the first 6 months.

CONCLUSIONS

Third-generation left ventricular assist device implants with a low rate of transplantation have similar survival to destination therapy, and are susceptible to long-term complications of VAD thrombosis and right heart failure.