P5419Cardiac reverse remodeling and recovery in dilated cardiomyopathy medication-naive patients requiring durable left ventricular assist device support

Background

Occasionally new onset cardiomyopathy patients (pts) present late and with such advanced disease stage that they cannot tolerate heart failure (HF) drug therapy. We sought to investigate the cardiac recovery (CR) potential following a combination of left ventricular assist device (LVAD) and guideline-directed HF drug therapy in this medication-naive population.

Methods

Chronic advanced HF requiring durable continuous-flow LVAD were prospectively evaluated. Patients with acute HF (myocarditis etc.) or post LVAD follow up <3 months were excluded. The “meds-treated” group (n=203) comprised patients treated adequately with at least one neurohormonal blocking agent during their HF history (b-blocker, ACEI/ARB, Aldosterone antagonist) and “meds-naive” group (n=8) comprised patients who were never before treated adequately with any HF medication. Baseline and follow up clinical, hemodynamic, imaging and laboratory data were analyzed. LVAD patients were phenotyped as CR responders or non responders, based on published predefined criteria.

Results

Univariate analysis showed that “med-naive” patients were younger, more likely to be on intravenous vasoactive agents, temporary mechanical support and with lower INTERMACS profile before LVAD implantation. Interestingly, no differences were seen in HF symptoms duration or other comorbidities. Baseline and follow up hemodynamics were similar in both groups, besides higher right atrial pressure pre-LVAD in the “meds-naive” group (16 vs 11 mmHg; p=0.04). Baseline echocardiographic (including LV dilation) and biochemical parameters revealed no differences between the groups, besides lower LVEF and higher BNP in the “meds-naive” group (14 vs 19%; p=0.03 and 2352 vs 1270; p=0.03, respectively). CR rates were significantly higher on “meds-naive” versus “meds-failed” group (50.0 vs 13.8%; p=0.005). Despite higher cardiac recovery rates in the “meds-naive” group the time course and magnitude of the favorable functional and structural response was similar among the CR responders of each of the 2 groups.

Conclusion

Young patients with new onset dilated cardiomyopathy sometimes present late, with advanced disease stage, unable to tolerate HF medications and requiring durable LVAD support. This patient population appears to have a potential for CR up to 50% and this could be factored in decisions surrounding their long-term therapeutic options.

P2628Predicting cardiac recovery before durable left ventricular assist device implantation in advanced heart failure patients

Background

Predicting cardiac recovery (CR) in advanced heart failure (HF) patients before left ventricular assist device (LVAD) implantation remains challenging. This study sought to investigate whether CR after LVAD unloading can be predicted by cardiac functional and structural parameters together with clinical characteristics.

Methods

From 2008 to 2016, consecutive advanced chronic HF patients (N=347) supported with durable continuous-flow LVADs were prospectively evaluated. Patients with acute HF etiologies or without adequate post-LVAD follow up (<3 months) were excluded. A great variety of clinical characteristics were evaluated in the remaining 285 subjects. LVAD patients were phenotyped while on support, as CR Responders or Non Responders, based on published predefined echocardiographic criteria. Multivariable logistic regression was used to form the model and the Utah Cardiac Recovery (UCAR) score was created from the regression beta coefficients of the final model.

Results

CR occurred in 13.7% of patients. Univariate analysis showed that responders were more likely to be young, female, non-ischemic cardiomyopathy, with shorter HF symptoms duration and no prior cardiac surgery. They had lower blood urea nitrogen and were more likely to be on temporary mechanical support before LVAD. The multivariable UCAR model (AUC=0.755; p<0.001) predicted CR using 3 clinical parameters – Figure.

Conclusion

Univariate and multivariable predictors of CR include both modifiable and non-modifiable patient characteristics that are known prior to LVAD implantation. The UCAR score can serve as a practical tool for targeted patient selection to implement protocols that facilitate CR in the advanced HF patient subpopulation that is most likely to respond.

Report From the American Society of Transplantation Conference on Donor Heart Selection in Adult Cardiac Transplantation in the United States

Cardiac transplantation remains the only definitive treatment for end-stage heart failure. Transplantation rates are limited by a shortage of donor hearts. This shortage is magnified because many hearts are discarded because of strict selection criteria and concern for regulatory reprimand for less-than-optimal posttransplant outcomes. There is no standardized approach to donor selection despite proposals to liberalize acceptance criteria. A donor heart selection conference was organized to facilitate discussion and generate ideas for future research. The event was attended by 66 participants from 41 centers with considerable experience in cardiac donor selection. There were state-of-the-art presentations on donor selection, with subsequent breakout sessions on standardizing the process and increasing utilization of donor hearts. Participants debated misconceptions and established agreement on donor and recipient risk factors for donor selection and identified the components necessary for a future donor risk score. Ideas for future initiatives include modification of regulatory practices to consider extended criteria donors when evaluating outcomes and prospective studies aimed at identifying the factors leading to nonacceptance of available donor hearts. With agreement on the most important donor and recipient risk factors, it is anticipated that a consistent approach to donor selection will improve rates of heart transplantation.

Threshold Dynamics of a Semiconductor Single Atom Maser

We demonstrate a single atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high-quality-factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masing transition. The observed threshold behavior is in agreement with an existing single atom maser theory when small corrections from lead emission are taken into account.