Surgical and transcatheter left atrial appendage closure in patients with atrial fibrillation and hypertrophic cardiomyopathy.

BACKGROUND: Patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) are at increased stroke risk in comparison to those with non-valvular AF not affected by HCM. OBJECTIVES: To investigate the role of left atrial appendage closure (LAAC) in patients with HCM and AF. METHODS AND RESULTS: We identified patients with HCM and AF using the National Readmission Dataset. Patients were stratified based on LAAC status. The primary efficacy outcome was a composite of ischaemic and haemorrhagic stroke, TIA, and all-cause mortality. The primary safety outcome was a composite of major bleeding and pericardial complications. Patients were matched using inverse probability of treatment weighting. Cox-proportional hazard regression was applied to calculate the hazard ratio (HR) with a 95% confidence interval (CI) on matched cohorts. We identified 71 980 patients with HCM and AF. 1351 (1.9%) patients underwent LAAC. Two hundred and eighty-seven (21.2%) underwent transcatheter LAAC. LAAC was associated with a lower risk of the primary efficacy outcome (2.5% vs. 5.4%, HR: 0.38; 95% CI: 0.17-0.88; P = 0.024), the primary safety outcome (2.9% vs. 6.8%, HR: 0.39; 95% CI: 0.23-0.66, P = 0.001), and reduced major bleeding. The LAAC group trended towards a lower risk of ischaemic stroke and all-cause mortality. CONCLUSION: Surgical and transcatheter LAAC was associated with a lower risk of haemorrhagic stroke and major bleeding.

Underutilization of Drug-Eluting Stents in Infrapopliteal Intervention for Chronic Limb-Threatening Ischemia.

PURPOSE: Multiple randomized clinical trials have shown superiority of drug-eluting stents (DES) over bare-metal stents (BMS) for infrapopliteal disease. However, real-world data on DES utilization and outcomes in infrapopliteal chronic limb-threatening ischemia (CLTI) patients are unknown. MATERIALS AND METHODS: We utilized the Nationwide Readmission Database (NRD) from 2016 to 2017 to extract patients undergoing infrapopliteal intervention with stents (BMS and DES) for CLTI using appropriate ICD-10 codes. Multilevel logistic regression with hospital ID as random effect was used to assess DES utilization. Primary outcome was the composite of target limb major amputation (TLmajA) and target limb revascularization (TLR). Multivariate Cox-proportional hazard regression was used to adjust for confounders. RESULTS: Our study included a total of 1817 patients. Of these patients, 1056 patients (58.1%) received DES; DES utilization was stable (relative change: +2.5%, p-trend: 0.867) between 2016 and 2017 and was higher in teaching hospitals (adjusted odds ratio [aOR] = 1.28, 95% CI = 1.03-1.61, p=0.029] and medium (aOR = 3.13, 95% CI = 2.17-4.55, p≤0.001) and large (aOR = 1.56, 95% CI = 1.14-2.17, p=0.005) bed-sized hospitals. Inter-class correlation was 0.44 suggesting ~44% variation in DES utilization between any 2 random hospitals; DES was associated with lower rate of the primary composite outcome (aHR = 0.75, 95% CI = 0.62-0.92, p=0.004) compared with BMS. CONCLUSION: In patients undergoing infrapopliteal intervention for CLTI, DES demonstrated significant underutilization despite supportive evidence of their superiority compared with BMS; DES was associated with improvement in the primary composite outcome compared with BMS.

Impact of catheter ablation in patients with atrial flutter and concurrent heart failure.

BACKGROUND: No studies assessed impact of atrial flutter (AFL) ablation on outcomes in patients with AFL and concurrent heart failure (HF). OBJECTIVES: To assess the effect of AFL ablation on mortality and HF readmissions in patients with AFL and HF. METHODS: This retrospective cohort study identified 15,952 patients with AFL and HF from the 2016-17 Nationwide Readmissions Database. The primary outcome was a composite of all-cause mortality and/or HF readmission at 1 year. Secondary outcomes included HF readmission, all-cause mortality, and atrial fibrillation (AF) readmission at 1 year. Propensity score match (1:2) algorithm was used to adjust for confounders. Cox proportional hazard regression was used to generate hazard ratios. RESULTS: Of the 15,952 patients, 9889 had heart failure with reduced ejection fraction (HFrEF) and 6063 had heart failure with preserved ejection fraction (HFpEF). In the matched HFrEF cohort (n = 5421), the primary outcome was significantly lower in patients undergoing ablation (HR 0.72, 95% CI 0.61-0.85, P < .001). HF readmission (HR 0.73, 95% CI 0.61-0.89, P = .001), all-cause mortality (HR 0.62, 95% CI 0.46-0.85, P = .003), and AF readmission (HR 0.63, 95% CI 0.48-0.82, P = .001) were also significantly reduced. In the matched HFpEF cohort (n = 2439), the primary outcome was lower in the group receiving ablation but was not statistically significant (HR 0.80, 95% CI 0.63-1.01, P = .065). CONCLUSION: In patients with AFL and HFrEF, AFL ablation was associated with lower mortality and HF readmissions at 1 year. Patients with AFL and HFpEF did not show a similar significant reduction in the primary outcome.

Calcified myocardial scar seen via cardiac imaging correlating with ventricular tachycardia focus.

A 74-year-old man presented with presyncope and non-sustained monomorphic ventricular tachycardia in the setting of acute coronary syndrome. On coronary angiogram, a calcified myocardial scar was revealed, which was later identified as the ventricular tachycardia focus via electrophysiological study.

Invasive Approaches in the Management of Cocaine-Associated Non-ST-Segment Elevation Myocardial Infarction.

OBJECTIVES: The aim of this study was to determine the impact of invasive approaches and revascularization in patients with cocaine-associated non-ST-segment elevation myocardial infarction (NSTEMI). BACKGROUND: The role of invasive approaches in cocaine-associated NSTEMI is uncertain. METHODS: This retrospective cohort study identified 3,735 patients with NSTEMI and history of cocaine use from the Nationwide Readmissions Database from 2016 to 2017. Invasive approaches were defined as coronary angiography, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Revascularization was defined as PCI and CABG. The primary efficacy outcome was major adverse cardiac events (MACE), and the primary safety outcome was emergent revascularization. Nonadherence was identified using appropriate International Classification of Diseases-Tenth Revision codes. Two propensity-matched cohorts were generated (noninvasive vs. invasive and noninvasive vs. revascularization) through multivariate logistic regression. RESULTS: In the propensity score-matched cohorts, an invasive approach (hazard ratio [HR]: 0.72; 95% confidence interval [CI]: 0.56 to 0.92; p = 0.008) and revascularization (HR: 0.54; 95% CI: 0.40 to 0.73; p < 0.001) (compared with a noninvasive approach) were associated with a lower rate of MACE, without an increase in emergent revascularization. On stratification, PCI and CABG individually were associated with a lower rate of MACE. Emergent revascularization was increased with PCI (HR: 1.78; 95% CI: 1.12 to 2.81; p = 0.014) but not with CABG. Nonadherent patients after PCI and CABG did not have significant difference in rate of MACE. PCI in nonadherent patients was associated with an increase in emergent revascularization (HR: 4.45; 95% CI: 2.07 to 9.57; p < 0.001). CONCLUSIONS: Invasive approaches and revascularization for cocaine-associated NSTEMI are associated with lower morbidity. A history of medical nonadherence was not associated with a difference in morbidity but was associated with an increased risk for emergent revascularization with PCI.

Transcatheter aortic valve replacement in aortic regurgitation: The U.S. experience.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) can be an effective option for high-risk Aortic Regurgitation (AR) patients. Although international experiences of TAVR for AR are published, U.S. data are limited. This study sought to report the short-term outcomes of TAVR in AR in the U.S. METHODS: Study cohorts were derived from the Nationwide Inpatient Sample (NIS) and Nationwide Readmissions Database (NRD) 2016-17. TAVR and AR were identified using ICD-10-CM-codes. The key outcomes were all-cause mortality, disabling stroke, valvular complications, complete heart block (CHB)/permanent pacemaker placement (PPM), open-heart surgery, acute kidney injury (AKI) requiring dialysis, and vascular complications. Multivariate logistic regression was used to adjust for confounders. RESULTS: 915 patients from the NIS (male-71%, age ≥65-84.2%) and 822 patients from the NRD (male-69.3%, age ≥65-80.5%) underwent TAVR for AR. The median length of stay (LOS) was 4 days for both cohorts. In-hospital mortality was 2.7%, and 30-day mortality was 3.3%. Disabling strokes were noted in 0.6% peri-procedurally and 1.8% at 30-days. Valve-related complications were 18-19% with paravalvular leak (4-7%) being the most common. Approximately 11% of patients developed CHB and/or needed PPM in both cohorts. In NRD, 2.2% of patients required dialysis for AKI, 1.5% developed vascular complications, and 0.6% required open-heart surgery within 30-days post-procedure. Anemia was predictive of increased overall complications and valvular complications, whereas peripheral vascular disease was a predictor of increased valvular complications and CHB/PPM. CONCLUSION: TAVR is a promising option in AR. Further studies are necessary for the expansion of TAVR as the standard treatment in AR.

Catheter Ablation for Atrial Fibrillation in Patients With Concurrent Heart Failure.

Due to limited real-world data, the aim of this study was to explore the impact of catheter ablation (CA) for atrial fibrillation (AF) in heart failure (HF). This retrospective cohort study identified 119,694 patients with AF and HF from the Nationwide Readmissions Database (NRD) from 2016 to 2017. Propensity-matching was generated using demographics, comorbidities, hospital and other characteristics through multivariate logistic regression. Greedy's propensity score match (1:15) algorithm was used to create matched data. The primary end point was a composite of HF readmission and mortality at 1 year. Secondary outcomes include HF readmission, mortality, AF readmission, and any-cause readmission at 1 year. Of the 119,694 patients, 63,299 had HF with reduced ejection fraction (HFrEF), and 56,395 had HF with preserved ejection fraction (HFpEF). In the overall HFrEF cohort, the primary outcome was similar (HR, 95% confidence interval, p-value) (1.01, 0.91 to 1.13, 0.811). AF readmission (0.41, 0.33 to 0.49, <0.001) and any readmission (0.87, 0.82 to 0.93, <0.001) were reduced with CA. In the propensity-matched HFrEF cohort, results were unchanged (primary outcome: 1.10, 0.95 to 1.27, 0.189; AF readmission: 0.46, 0.36 to 0.59, <0.001; any readmission: 0.89, 0.82 to 0.98, 0.015). In the overall HFpEF cohort, the primary outcome was similar (0.90, 0.78 to 1.04, 0.154). AF readmission was reduced with CA (0.54, 0.44 to 0.65, <0.001). In the propensity-matched HFpEF cohort, results were unchanged (primary outcome 1.10, 0.92 to 1.31, 0.289; AF readmission 0.44, 0.33 to 0.57, <0.001). CA did not reduce mortality and HF readmission at one year irrespective of the type of HF, but significantly reduce readmission due to AF.

Evaluation and Treatment of Severe Rhabdomyolysis in a Patient with Legionnaires' Disease.

A 53-year-old man with alcoholism and a three-day history of diarrhea and abdominal pain was hospitalized with mild acute kidney injury (AKI) and rhabdomyolysis after a fall where he was down for a short duration. Subsequent testing revealed patchy right lower lobe infiltrates on chest X-ray and a positive urinary Legionella antigen test. Creatinine phosphokinase (CPK) peaked at 85,780 U/L (normal 0-250) on hospital day two and remained markedly elevated for five days despite aggressive intravenous (IV) hydration and appropriate antibiotic treatment. When the patient defervesced and showed clinical signs of resolution of pneumonia, the CPK level declined rapidly, and renal function returned to baseline. Rhabdomyolysis with AKI is a rare but serious complication of Legionella pneumonia, with most patients requiring dialysis. Our patient's complete recovery without renal replacement therapy can probably be attributed to his normal baseline renal function, timely diagnosis of his Legionella-associated rhabdomyolysis, and prompt treatment with aggressive IV hydration and appropriate antibiotics. Legionella infection should be considered in acutely ill patients with rhabdomyolysis of unclear etiology.

High Thoracic Disc Herniation Causing Horner Syndrome with the Intraoperative Finding of Conjoined Nerve Root Compression: A Case Report.

CASE: A 29-year-old man presented with right medial arm pain with paresthesia, as well as right-sided ptosis, miosis, and anhidrosis. Magnetic resonance imaging revealed a right paracentral disc herniation at the T1-T2 level. The patient underwent a hemilaminectomy with a medial facetectomy through a posterolateral approach to the T1-T2 disc space, followed by a discectomy. Intraoperative findings were notable for a conjoined nerve root. CONCLUSION: Although high thoracic disc herniation is rare, its diagnosis should be considered when patients present with radicular arm pain and Horner syndrome. A high index of suspicion should be maintained for nerve root anomalies to limit iatrogenic injury and to ensure successful decompression.

Na+ inhibits the epithelial Na+ channel by binding to a site in an extracellular acidic cleft.

The epithelial Na(+) channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na(+), Cl(-), protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na(+) concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na(+) binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na(+). Mutations at selected sites altered the cation inhibitory preference to favor Li(+) or K(+) rather than Na(+). Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na(+). Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family.

Inhibitory tract traps the epithelial Na+ channel in a low activity conformation.

Proteolysis plays an important role in the maturation and activation of epithelial Na(+) channels (ENaCs). Non-cleaved channels are inactive at high extracellular Na(+) concentrations and fully cleaved channels are constitutively active. Cleavage of the α and γ subunits at multiple sites activates the channel through the release of imbedded inhibitory tracts. Peptides derived from these released tracts are also inhibitory, likely through binding at the inhibitory tract sites. We recently reported a model of the α subunit. We have now cross-linked Cys derivatives of the inhibitory peptide to the channel, using our model to predict sites at a domain interface of the α subunit that is in proximity to the N terminus of the peptide. Furthermore, peptide inhibition was mimicked in the absence of peptide by cross-linking the channel across the domain interface. Our results suggest a dynamic domain interface that can be exploited by inhibitory peptides and provides a mechanism for peptide inhibition and proteolytic activation.

Constraint-based, homology model of the extracellular domain of the epithelial Na+ channel α subunit reveals a mechanism of channel activation by proteases.

The epithelial Na(+) channel (ENaC) mediates Na(+) transport across high resistance epithelia. This channel is assembled from three homologous subunits with the majority of the protein's mass found in the extracellular domains. Acid-sensing ion channel 1 (ASIC1) is homologous to ENaC, but a key functional domain is highly divergent. Here we present molecular models of the extracellular region of α ENaC based on a large data set of mutations that attenuate inhibitory peptide binding in combination with comparative modeling based on the resolved structure of ASIC1. The models successfully rationalized the data from the peptide binding screen. We engineered new mutants that had not been tested based on the models and successfully predict sites where mutations affected peptide binding. Thus, we were able to confirm the overall general fold of our structural models. Further analysis suggested that the α subunit-derived inhibitory peptide affects channel gating by constraining motions within two major domains in the extracellular region, the thumb and finger domains.