Device exchange from Heartmate II to HeartWare HVAD.

BACKGROUND: Despite technological advancements, pump durability and pump-related complications continue to affect and adversely impact the lives of patients with end-stage heart failure on left ventricular assist device (LVAD) support. In an attempt to avoid recurrent LVAD-related complications, there may be circumstances where it is clinically advantageous to exchange a patient's device from HeartMate II to HeartWare HVAD. However, there is a paucity of data that describes the safety and feasibility of such an approach. OBJECTIVE: We present the largest single-center series of HeartMate II (HMII) to HeartWare (HVAD) device exchanges. METHODS: A retrospective review of 11 patients who underwent HMII to HVAD exchange from 2012 to 2017 was conducted to evaluate patient characteristics, incidence of postoperative complications, and survival. RESULTS: Eleven male patients (mean age 55 ± 14.4 years) underwent HMII to HVAD device exchange. One patient expired on postoperative day 7 secondary to sepsis. One patient was lost-to-follow-up after 23 months. An additional three patients died at 5, 7, and 24 months. Mean follow-up after device exchange was 1555 ± 311 days for the remaining six patients. None of the 11 study patients underwent LVAD explant, further device exchange, or heart transplant. CONCLUSION: Exchange of an HMII LVAD to an HVAD can be performed safely with acceptable perioperative morbidity and mortality.

Genome-wide analyses in bacteria show small-RNA enrichment for long and conserved intergenic regions.

Interest in finding small RNAs (sRNAs) in bacteria has significantly increased in recent years due to their regulatory functions. Development of high-throughput methods and more sophisticated computational algorithms has allowed rapid identification of sRNA candidates in different species. However, given their various sizes (50 to 500 nucleotides [nt]) and their potential genomic locations in the 5' and 3' untranslated regions as well as in intergenic regions, identification and validation of true sRNAs have been challenging. In addition, the evolution of bacterial sRNAs across different species continues to be puzzling, given that they can exert similar functions with various sequences and structures. In this study, we analyzed the enrichment patterns of sRNAs in 13 well-annotated bacterial species using existing transcriptome and experimental data. All intergenic regions were analyzed by WU-BLAST to examine conservation levels relative to species within or outside their genus. In total, more than 900 validated bacterial sRNAs and 23,000 intergenic regions were analyzed. The results indicate that sRNAs are enriched in intergenic regions, which are longer and more conserved than the average intergenic regions in the corresponding bacterial genome. We also found that sRNA-coding regions have different conservation levels relative to their flanking regions. This work provides a way to analyze how noncoding RNAs are distributed in bacterial genomes and also shows conserved features of intergenic regions that encode sRNAs. These results also provide insight into the functions of regions surrounding sRNAs and into optimization of RNA search algorithms.

Transcriptional analysis of Deinococcus radiodurans reveals novel small RNAs that are differentially expressed under ionizing radiation.

Small noncoding RNAs (sRNAs) are posttranscriptional regulators that have been identified in multiple species and shown to play essential roles in responsive mechanisms to environmental stresses. The natural ability of specific bacteria to resist high levels of radiation has been of high interest to mechanistic studies of DNA repair and biomolecular protection. Deinococcus radiodurans is a model extremophile for radiation studies that can survive doses of ionizing radiation of >12,000 Gy, 3,000 times higher than for most vertebrates. Few studies have investigated posttranscriptional regulatory mechanisms of this organism that could be relevant in its general gene regulatory patterns. In this study, we identified 199 potential sRNA candidates in D. radiodurans by whole-transcriptome deep sequencing analysis and confirmed the expression of 41 sRNAs by Northern blotting and reverse transcriptase PCR (RT-PCR). A total of 8 confirmed sRNAs showed differential expression during recovery after acute ionizing radiation (15 kGy). We have also found and confirmed 7 sRNAs in Deinococcus geothermalis, a closely related radioresistant species. The identification of several novel sRNAs in Deinococcus bacteria raises important questions about the evolution and nature of global gene regulation in radioresistance.

Continuous-Flow Left Ventricular Assist Device Support in Patients with Ischemic Versus Nonischemic Cardiomyopathy.

To determine whether the cause of cardiomyopathy affects outcomes in patients who undergo continuous-flow left ventricular assist device support, we compared postimplant adverse events and survival between patients with ischemic and nonischemic cardiomyopathy. The inclusion criteria for the ischemic group were a history of myocardial infarction or revascularization (coronary artery bypass grafting or percutaneous coronary intervention), ≥75% stenosis of the left main or proximal left anterior descending coronary artery, or ≥75% stenosis of ≥2 epicardial vessels. From November 2003 through March 2016, 526 patients underwent device support: 256 (48.7%) in the ischemic group and 270 (51.3%) in the nonischemic group. The ischemic group was older (60.0 vs 50.0 yr), included more men than women (84.0% vs 72.6%), and had more comorbidities. More patients in the nonischemic group were able to have their devices explanted after left ventricular recovery (5.9% vs 2.0%; P=0.02). More patients in the ischemic group had gastrointestinal bleeding (31.2% vs 22.6%; P=0.03), particularly from arteriovenous malformations (20.7% vs 11.9%; P=0.006) and ulcers (16.4% vs 9.3%; P=0.01). Kaplan-Meier analysis revealed no difference in overall survival between groups (P=0.24). Older age, previous sternotomy, higher total bilirubin level, and concomitant procedures during device implantation independently predicted death (P ≤0.03), whereas cause of heart failure did not (P=0.08). Despite the similarity in overall survival between groups, ischemic cardiomyopathy was associated with more frequent gastrointestinal bleeding. This information may help guide the care of patients with ischemic cardiomyopathy who receive continuous-flow left ventricular assist device support.

Current Surgical Risk Scores Overestimate Risk in Minimally Invasive Aortic Valve Replacement.

OBJECTIVE: Risk-scoring systems for surgical aortic valve replacement (AVR) were largely derived from sternotomy cases. We evaluated the accuracy of current risk scores in predicting outcomes after minimally invasive AVR (mini-AVR). Because transcatheter AVR (TAVR) is being considered for use in low-risk patients with aortic stenosis, accurate mini-AVR risk assessment is necessary. METHODS: We reviewed 1,018 consecutive isolated mini-AVR cases (2009 to 2015). After excluding patients with Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) scores ≥4, we calculated each patient's European System for Cardiac Operative Risk Evaluation (EuroSCORE) II, TAVR Risk Score (TAVR-RS), and age, creatinine, and ejection fraction score (ACEF). We compared all 4 scores' accuracy in predicting mini-AVR 30-day mortality by computing each score's observed-to-expected mortality ratio (O:E). Area under the receiver operating characteristic (ROC) curves tested discrimination, and the Hosmer-Lemeshow goodness-of-fit tested calibration. RESULTS: Among 941 patients (mean age, 72 ± 12 years), 6 deaths occurred within 30 days (actual mortality rate, 0.6%). All 4 scoring systems overpredicted expected mortality after mini-AVR: ACEF (1.4%), EuroSCORE II (1.9%), STS-PROM (2.0%), and TAVR-RS (2.1%). STS-PROM best estimated risk for patients with STS-PROM scores 0 to <1 (0.6 O:E), ACEF for patients with STS-PROM scores 2 to <3 (0.6 O:E), and TAVR-RS for patients with STS-PROM scores 3 to <4 (0.7 O:E). ROC curves showed only fair discrimination and calibration across all risk scores. CONCLUSIONS: In low-risk patients who underwent mini-AVR, current surgical scoring systems overpredicted mortality 2-to-3-fold. Alternative dedicated scoring systems for mini-AVR are needed for more accurate outcomes assessment.

Effect of cardiac arrest with aortic cross-clamping during left ventricular assist device implantation.

OBJECTIVES: Some patients who undergo continuous-flow left ventricular assist device (CF-LVAD) implantation require concomitant procedures that can be performed with or without cardiac arrest under aortic cross-clamping (AXC). Procedures normally performed with cardiac arrest are sometimes avoided or performed without cardiac arrest because it may be detrimental to right heart function. However, the effects of cardiac arrest on patients with advanced heart failure necessitating CF-LVAD support have not been thoroughly studied. We examined our single-centre experience to determine whether cardiac arrest during CF-LVAD implantation was associated with worse patient outcomes. METHODS: From November 2003 to March 2016, a total of 526 patients with chronic end-stage heart failure underwent primary CF-LVAD implantation. Preoperative demographics, postoperative complications and mortality rates were compared between patients who required cardiac arrest with AXC (n = 50) and those who did not (n = 476). RESULTS: The most frequently performed procedure requiring AXC was aortic valve closure (n = 23, 26.1%). Although the AXC group had longer cardiopulmonary bypass times (P < 0.01), long-term (5-year) survival was similar in AXC and non-AXC patients (P = 0.13). Also, postoperative right heart failure (P = 0.15) and neurological dysfunction (P = 0.89) rates were not significantly different between the 2 groups. Cox proportional hazards analysis showed that cardiac arrest with AXC was not an independent predictor of mortality (hazard ratio, 0.89; P = 0.73). CONCLUSIONS: Cardiac arrest with AXC during CF-LVAD implantation did not negatively affect long-term survival or the incidence of right ventricular failure or stroke. These findings should be considered in deciding surgical strategies. Additional investigation may be warranted to further understand the effects of cardiac arrest during LVAD implantation.

Outcomes of Repeat Left Ventricular Assist Device Exchange.

Implantable continuous-flow left ventricular assist devices (CF-LVADs) are used for long-term LV support in bridging patients to heart transplantation or as destination therapy. With prolonged support times, some patients will have repeat complications necessitating multiple device exchanges. To elucidate the safety and efficacy of repeat device exchange, we retrospectively reviewed data from 25 patients who underwent two or more CF-LVAD implantations between July 2005 and August 2017. Indications for exchange were thrombus/hemolysis (n = 8, 32%), electromechanical device malfunction (n = 14, 56%), and infection (n = 3, 12%). The implanted devices were the HeartMate II (n = 13, 52%), the HeartWare HVAD (n = 11, 44%), and the Jarvik 2000 (n = 1, 4%). Average hospital length of stay was 44 days (range 4-221 days), and 17 patients (68%) survived to discharge. Average duration of support after the most recent LVAD implantation was 802 days (range 1-3,229 days). Overall survival was 72% at 1 year and 60% at 2 years. Postoperative complications included respiratory failure in five patients (20%), device infection in five (20%), bleeding requiring reoperation in four (16%), neurologic dysfunction in four (16%), and acute renal failure in two (8%). Overall, our data suggest that repeat LVAD exchange is a feasible option for patients with recurrent device-related complications.

Confusion Instead of Clarity: Publicly Reported Cardiac Surgery Ratings for Coronary Artery Bypass Grafting and Aortic Valve Replacement.

BACKGROUND: Public reporting of cardiac surgery ratings has been advocated to inform patient selection of hospitals. Although Society of Thoracic Surgeons (STS) ratings are based on audited risk-adjusted patient outcomes, other rating systems rely on administrative databases. In this study, we evaluate correlation among 4 widely used hospital rating systems for coronary artery bypass grafting (CABG) and aortic valve replacement (AVR). STUDY DESIGN: We identified an initial cohort of 602 hospitals from US News & World Report's (USN) listing of the 2016-2017 "Best Hospitals for Cardiology & Heart Surgery." From this cohort, current publicly available CABG and AVR ratings were collected from the STS, USN, Centers for Medicare & Medicaid Services, and Healthgrades. All 4 rating systems rated hospitals as high, average, or below average performers for each procedure. We then determined the match rate between rating systems for individual hospitals and assessed interrater reliability with Cohen's κ. RESULTS: Rating systems had different distributions of high and low performing ratings assigned. USN rated hospitals as high performing for both CABG and AVR more frequently compared with STS, Healthgrades, and Centers for Medicare & Medicaid Services. For CABG, the match rate between systems varied from 50% to 85%, with the best match between STS and Centers for Medicare & Medicaid Services. Similarly for AVR, the match rate varied from 50% to 73%, with the best match between STS and Healthgrades. Interrater reliability was poor among the 4 rating systems (κ < 0.2) and consistent with no agreement for CABG and AVR ratings. CONCLUSIONS: Publicly reported cardiac surgery ratings have significant discrepancy and poor correlation. This might confuse instead of clarify public perception of hospital quality for cardiac surgery.

Room temperature electrodeposition of molybdenum sulfide for catalytic and photoluminescence applications.

An elegant method for the electrodeposition of MoS2 thin films using room temperature ionic liquids (RTIL) as an electrolyte was developed. Simple molecular precursors of Mo and S were added in different concentrations to tune the composition and deposition process. The electrodeposition of MoS2 was confirmed with both Raman spectroscopy and XPS. Analysis showed that the electrodeposited MoS2 films form a flower shape morphology with edge active sites that promote the hydrogen evolution reaction (HER). Furthermore, this technique enables selective tuning of the film thickness and demonstrates high photoluminescence activity with a decrease in the number of layers.