Association of Renin-Angiotensin-Aldosterone System Inhibitors With Clinical Outcomes, Hemodynamics, and Myocardial Remodeling Among Patients With Advanced Heart Failure on Left Ventricular Assist Device Support

BACKGROUND

We evaluated the potential benefits of renin-angiotensin-aldosterone system inhibitors (RAASi) in patients with left ventricular assist device support.

METHODS AND RESULTS

A total of 165 consecutive patients undergoing left ventricular assist device implant and alive at 6-month on support were studied. RAASi status after 6-month visit along with clinical reasons for nonprescription/uptitration were retrospectively assessed. The primary outcome was a composite of heart failure hospitalization or cardiovascular death between 6 and 24 months after left ventricular assist device implant. Remodeling and hemodynamic outcomes were explored by studying the association of RAASi new prescription/uptitration versus unmodified therapy at 6-month visit with the change in echocardiographic parameters and hemodynamics between 6 and 18 months. After the 6-month visit, 76% of patients were on RAASi. Patients' characteristics among those receiving and not receiving RAASi were mostly similar. Of 85 (52%) patients without RAASi new prescription/uptitration at 6-month visit, 62% had no apparent clinical reason. RAASi were independently associated with the primary outcome (adjusted hazard ratio, 0.31 [95% CI, 0.16-0.69]). The baseline rates of optimal echocardiographic profile (neutral interventricular septum, mitral regurgitation less than mild, and aortic valve opening) and hemodynamic profile (cardiac index ≥2.2 L/min per m2, wedge pressure <18 mm Hg, and right atrial pressure <12 mm Hg) were similar between groups. At 18 months, patients receiving RAASi new prescription/uptitration at 6 months had higher rates of optimal hemodynamic profile (57.5% versus 37.0%; P=0.032) and trends for higher rates of optimal echocardiographic profile (39.6% versus 22.9%; P=0.055) compared with patients with 6-month unmodified therapy. Optimal 18-month hemodynamic and echocardiographic profiles were associated with the primary outcome (log-rank=0.022 and log-rank=0.035, respectively).

CONCLUSIONS

RAASi are associated with improved outcomes and improved hemodynamics among mechanically unloaded patients.

The challenge of advanced therapies in the contemporary era: first in Europe ECPELLA long-distance transfer-a case report

Background

The use of mechanical circulatory support (MCS) has markedly increased over the last decade, so have the inter-hospital transfers, with the aim of being able to offer advanced heart failure (AHF) therapies and centralizing patients to tertiary centres.

Case summary

In this article, we present the first in Europe long-distance air transfer of a patient supported by veno-arterial extracorporeal membrane oxygenator and Impella (ECPELLA), as a bridge to successful heart transplant. In our case report, a foreign young patient with AHF due to familiar cardiomyopathy required multiple MCS devices to achieve cardiovascular stability. After appropriate planning and multidisciplinary discussion, the patient was transferred on MCS to his country of origin via a fixed-wing airplane, in order to be assessed for heart transplantation. During take-off, the Impella flows temporarily dropped and a suction alarm was displayed; however, this rectified without intervention, and the rest of the flight was uneventful. One month after transfer, the patient underwent successful heart transplantation and remained clinically stable during the 12-month follow-up.

Discussion

Our experience links together the current challenges in the evolving AHF strategies and the increased need for inter-facility cooperation. Both these clinical and logistic challenges appear to lead to possible improved outcomes, after appropriate assessment, training, and accurate planning. Our experience provides useful information on feasibility of long-distance transport of patients supported by ECPELLA in Europe.

British societies guideline on the management of emergencies in implantable left ventricular assist device recipients in transplant centres

An implantable left ventricular assist device (LVAD) is indicated as a bridge to transplantation or recovery in the United Kingdom (UK). The mechanism of action of the LVAD results in a unique state of haemodynamic stability with diminished arterial pulsatility. The clinical assessment of an LVAD recipient can be challenging because non-invasive blood pressure, pulse and oxygen saturation measurements may be hard to obtain. As a result of this unusual situation and complex interplay between the device and the native circulation, resuscitation of LVAD recipients requires bespoke guidelines. Through collaboration with key UK stakeholders, we assessed the current evidence base and developed guidelines for the recognition of clinical deterioration, inadequate circulation and time-critical interventions. Such guidelines, intended for use in transplant centres, are designed to be deployed by those providing immediate care of LVAD patients under conditions of precipitous clinical deterioration. In summary, the Joint British Societies and Transplant Centres LVAD Working Group present the UK guideline on management of emergencies in implantable LVAD recipients for use in advanced heart failure centres. These recommendations have been made with a UK resuscitation focus but are widely applicable to professionals regularly managing patients with implantable LVADs.

Oral milrinone for management of refractory right ventricular failure in patients with left ventricular assist devices

AIMS

We present a single-centre retrospective experience using oral milrinone in patients with a left ventricular assist device (LVAD) and concurrent refractory right ventricular failure.

METHODS AND RESULTS

All patients implanted with LVAD between January 2013 and July 2021 from a high-volume advanced heart failure service were reviewed. Eight patients were initiated on oral milrinone during this period. Oral milrinone was started 1.5 [inter-quartile range (IQR) 1-2.3] years after LVAD implantation and continued for 1.2 (IQR 0.5-2.8) years. Therapeutic milrinone levels were achieved (232.2 ± 153.4 ng/mL) with 62.4 ± 18% of time within the therapeutic range. Two patients had adverse events (non-sustained ventricular tachycardia and ventricular fibrillation effectively treated by internal cardioverter defibrillator) but did not require milrinone discontinuation. Four deaths occurred, one after transplant and three from disease progression determined to be unrelated to oral milrinone use. Three patients continue oral milrinone therapy in the community. There was no significant difference found after the initiation of oral milrinone on any of the physiological measures; however, there were trends in reduction of New York Heart Association class from 3.4 ± 0.5 to 3.0 ± 0.8 (P = 0.08), reduction of right atrial/wedge pressure from 0.9 ± 0.3 to 0.5 ± 0.2 (P = 0.08), and improvement of right ventricular stroke work index from 3.8 ± 2 to 5.8 ± 2.7 (P = 0.16).

CONCLUSIONS

Oral milrinone appears safe for long-term use in the outpatient setting when combined with therapeutic monitoring in this complex medical cohort with limited management options. Further study is needed to ascertain whether this treatment is effective in reducing heart failure symptoms and admissions.

Mechanical life support algorithm developed by simulation for inpatient emergency management of recipients of implantable left ventricular assist devices

Background

Published guidance concerning emergency management of left ventricular assist device (LVAD) recipients is both limited and lacking in consensus which increases the risk of delayed and/or inappropriate actions.

Methods

In our specialist tertiary referral centre we developed, by iteration, a novel in-hospital resuscitation algorithm for LVAD emergencies which we validated through simulation and assessment of our multi-disciplinary team. A Mechanical Life Support course was established to provide theoretical and practical education combined with simulation to consolidate knowledge and confidence in algorithm use. We assessed these measures using confidence scoring, a key performance indicator (the time taken to restart LVAD function) and a multiple-choice question (MCQ) examination.

Results

The mean baseline staff confidence score in management of LVAD emergencies was 2.4 ± 1.2 out of a maximum of 5 (n = 29). After training with simulation, mean confidence score increased to 3.5 ± 0.8 (n = 13).

Clinical personnel who were provided with the novel resuscitation algorithm were able to reduce time taken to restart LVAD function from a mean value of 49 ± 8.2 seconds (pre-training) to 20.4 ± 5 seconds (post-training) (n = 42, p < 0.0001).

The Mechanical Life Support course increased mean confidence from 2.5 ± 1.2 to 4 ± 0.6 (n = 44, p < 0.0001) and mean MCQ score from 18.7 ± 3.4 to 22.8 ± 2.6, out of a maximum of 28 (n = 44, p < 0.0001).

Conclusion

We present a simplified LVAD Advanced Life Support algorithm to aid the crucial first minutes of resuscitation where basic interventions are likely to be critical in assuring good patient outcomes.

A detailed explantation assessment protocol for patients with left ventricular assist devices with myocardial recovery

OBJECTIVES

Left ventricular assist device (LVAD) implantation for end-stage heart failure patients has been on the rise, providing a reliable long-term option. For some LVAD patients, longer term LV unloading leads to recovery; hence, the need for evaluating potential myocardial recovery and weaning eligibility has emerged.

METHODS

All patients who underwent contemporary LVAD explantation at our institution between 2009 and 2020 were included in the study. Patients in New York Heart Association I, left ventricular ejection fraction >40%, a cardiac index >2.4 l/min and a peak oxygen intake >50% predicted underwent a 4-phase weaning assessment. A minimally invasive approach using a titanium plug was the surgery of choice in the most recent explants. Kaplan-Meier curves were used to estimate the survival at 1 and 5 years.

RESULTS

Twenty-six patients (17 HeartMate II, 9 HeartWare) underwent LVAD explantation after a median 317 days of support [IQ (212-518)], range 131-1437. Mean age at explant was 35.8 ± 12.7 years and 85% were males. Idiopathic dilated cardiomyopathy was the underlying diagnosis in 70% of cases. Thirteen (48%) patients were on short-term mechanical circulatory support and 60% required intensive care unit admission prior to the LVAD implantation. At 1 year, Kaplan-Meier estimated survival was 88%, whereas at 6 years, it was 77%. The average left ventricular ejection fraction at 1 year post-explant was 44.25% ± 8.44.

CONCLUSIONS

The use of a standardized weaning protocol (echocardiographic and invasive) and a minimally invasive LVAD explant technique minimizes periprocedural complications and leads to good long-term device-free survival rates.

Ileal smooth muscle dysfunction and remodeling in cystic fibrosis

Patients with cystic fibrosis (CF) often suffer from gastrointestinal cramps and intestinal obstruction. The CF transmembrane conductance regulator (CFTR) channel has been shown to be expressed in vascular and airway smooth muscle (SM). We hypothesized that the absence of CFTR expression alters the gastrointestinal SM function and that these alterations may show strain-related differences in the mouse. The aim of this study was to measure the contractile properties of the ileal SM in two CF mouse models. CFTR(-/-) and CFTR(+/+) mice were studied on BALB/cJ and C57BL/6J backgrounds. Responsiveness of ileal strips to electrical field stimulation (EFS), methacholine (MCh), and isoproterenol was measured. The mass and the cell density of SM layers were measured morphometrically. Finally, the maximal velocity of shortening (Vmax) and the expression of the fast (+)insert myosin isoform were measured in the C57BL/6J ileum. Ileal hyperreactivity was observed in response to EFS and MCh in CFTR(-/-) compared with CFTR(+/+) mice in C57BL/6J background. This latter observation was not reproduced by acute inhibition of CFTR with CFTR(inh)172. BALB/cJ CFTR(-/-) mice exhibited a significant increase of SM mass with a lower density of cells compared with CFTR(+/+), whereas no difference was observed in the C57BL/6J background. In addition, in this latter strain, ileal strips from CFTR(-/-) exhibited a significant increase in Vmax compared with control and expressed a greater proportion of the fast (+)insert SM myosin isoform with respect to total myosin. BALB/cJ CFTR(-/-) ilium had a greater relaxation to isoproterenol than the CFTR(+/+) mice when precontracted with EFS, but no difference was observed in response to exogeneous MCh. In vivo, the lack of CFTR expression induces a different SM ileal phenotype in different mouse strains, supporting the importance of modifier genes in determining intestinal SM properties.