Atrial fibrillation, cognition and dementia: A review.

Atrial fibrillation (AF) is one of the most common types of cardiac arrhythmia, particularly among older adults. AF confers a 5-fold risk for thromboembolic stroke as well as a 2-fold higher risk for congestive heart failure, morbidity, and mortality. Although stroke remains an important and impactful complication of AF, recent studies have shown that AF is independently associated with other neurological disorders, including cognitive impairment and dementia, even after adjusting for prior ischemic stroke. We performed a review of the published literature on the association between AF and cognitive status. Further, we reviewed studies investigating the underlying mechanisms for this association and/or reporting the impact of AF treatment on cognitive function. While most published studies demonstrate associations between AF and impaired cognition, no AF treatment has yet been associated with a reduced incidence of cognitive decline or dementia.

Calmodulin and CaMKII modulate ENaC activity by regulating the association of MARCKS and the cytoskeleton with the apical membrane.

Phosphatidylinositol bisphosphate (PIP2) regulates epithelial sodium channel (ENaC) open probability. In turn, myristoylated alanine-rich C kinase substrate (MARCKS) protein or MARCKS-like protein 1 (MLP-1) at the plasma membrane regulates the delivery of PIP2 to ENaC. MARCKS and MLP-1 are regulated by changes in cytosolic calcium; increasing calcium promotes dissociation of MARCKS from the membrane, but the calcium-regulatory mechanisms are unclear. However, it is known that increased intracellular calcium can activate calmodulin and we show that inhibition of calmodulin with calmidazolium increases ENaC activity presumably by regulating MARCKS and MLP-1. Activated calmodulin can regulate MARCKS and MLP-1 in two ways. Calmodulin can bind to the effector domain of MARCKS or MLP-1, inactivating both proteins by causing their dissociation from the membrane. Mutations in MARCKS that prevent calmodulin association prevent dissociation of MARCKS from the membrane. Calmodulin also activates CaM kinase II (CaMKII). An inhibitor of CaMKII (KN93) increases ENaC activity, MARCKS association with ENaC, and promotes MARCKS movement to a membrane fraction. CaMKII phosphorylates filamin. Filamin is an essential component of the cytoskeleton and promotes association of ENaC, MARCKS, and MLP-1. Disruption of the cytoskeleton with cytochalasin E reduces ENaC activity. CaMKII phosphorylation of filamin disrupts the cytoskeleton and the association of MARCKS, MLP-1, and ENaC, thereby reducing ENaC open probability. Taken together, these findings suggest calmodulin and CaMKII modulate ENaC activity by destabilizing the association between the actin cytoskeleton, ENaC, and MARCKS, or MLP-1 at the apical membrane.

Procedural success in transaxillary transcatheter aortic valve implantation according to type of transcatheter heart valve: results from the multicenter TAXI registry.

BACKGROUND: Transaxillary (TAx) transcatheter aortic valve implantation (TAVI) is a preferred alternative access in patients ineligible for transfemoral TAVI. AIMS: This study used the Trans-AXillary Intervention (TAXI) registry to compare procedural success according to different types of transcatheter heart valves (THV). METHODS: For the TAXI registry anonymized data of patients treated with TAx-TAVI were collected from 18 centers. Acute procedural, early and 1-month clinical outcomes were adjudicated in accordance with standardized VARC-3 definitions. RESULTS: From 432 patients, 368 patients (85.3%, SE group) received self-expanding (SE) THV and 64 patients (14.8%, BE group) received balloon-expandable (BE) THV. Imaging revealed lower axillary artery diameters in the SE group (max/min diameter in mm: 8.4/6.6 vs 9.4/6.8 mm; p < 0.001/p = 0.04) but a higher proportion of axillary tortuosity in BE group (62/368, 23.6% vs 26/64, 42.6%; p = 0.004) with steeper aorta-left ventricle (LV) inflow (55° vs 51°; p = 0.002) and left ventricular outflow tract (LVOT)-LV inflow angles (40.0° vs 24.5°; 0.002). TAx-TAVI was more often conducted by right sided axillary artery in the BE group (33/368, 9.0% vs 17/64, 26.6%; p < 0.001). Device success was higher in the SE group (317/368, 86.1% vs 44/64, 68.8%, p = 0.0015). In logistic regression analysis, BE THV were a risk factor for vascular complications and axillary stent implantation. CONCLUSIONS: Both, SE and BE THV can be safely used in TAx-TAVI. However, SE THV were more often used and were associated with a higher rate of device success. While SE THV were associated with lower rates of vascular complications, BE THV were more often used in cases with challenging anatomical circumstances.

Predicting in-hospital mortality after transcatheter aortic valve replacement using administrative data and machine learning.

Transcatheter aortic valve replacement (TAVR) is the gold standard treatment for patients with symptomatic aortic stenosis. The utility of existing risk prediction tools for in-hospital mortality post-TAVR is limited due to two major factors: (a) the predictive accuracy of these tools is insufficient when only preoperative variables are incorporated, and (b) their efficacy is also compromised when solely postoperative variables are employed, subsequently constraining their application in preoperative decision support. This study examined whether statistical/machine learning models trained with solely preoperative information encoded in the administrative National Inpatient Sample database could accurately predict in-hospital outcomes (death/survival) post-TAVR. Fifteen popular binary classification methods were used to model in-hospital survival/death. These methods were evaluated using multiple classification metrics, including the area under the receiver operating characteristic curve (AUC). By analyzing 54,739 TAVRs, the top five classification models had an AUC ≥ 0.80 for two sampling scenarios: random, consistent with previous studies, and time-based, which assessed whether the models could be deployed without frequent retraining. Given the minimal practical differences in the predictive accuracies of the top five models, the L2 regularized logistic regression model is recommended as the best overall model since it is computationally efficient and easy to interpret.

Percutaneous vs. surgical axillary access for transcatheter aortic valve implantation: the TAXI registry.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an established management strategy for severe aortic valve stenosis. Percutaneous axillary approach for TAVI holds the promise of improving safety without jeopardizing effectiveness in comparison to surgical access. We aimed at appraising the comparative effectiveness of percutaneous vs. surgical axillary approaches for TAVI. METHODS: We performed an international retrospective observational study using de-identified details on baseline, procedural, and 1-month follow-up features. Valve Academic Research Consortium (VARC)-3 criteria were applied throughout. Outcomes of interest were clinical events up to 1 month of follow-up, compared with unadjusted and propensity score-adjusted analyses. RESULTS: A total of 432 patients were included, 189 (43.8%) receiving surgical access, and 243 (56.2%) undergoing percutaneous access. Primary hemostasis failure was more common in the percutaneous group (13.2% vs. 4.2%, P<0.001), leading to more common use of covered stent implantation (13.2% vs. 3.7%, P<0.001). Irrespectively, percutaneous access was associated with shorter hospital stay (-2.6 days [95% confidence interval: -5.0; -0.1], P=0.038), a lower risk of major adverse events (a composite of death, myocardial infarction, stroke, type 3 bleeding, and major access-site related complication; odds ratio=0.44 [0.21; 0.95], P=0.036), major access-site non-vascular complications (odds ratio=0.21 [0.06; 0.77], P=0.018), and brachial plexus impairment (odds ratio=0.16 [0.03; 0.76], P=0.021), and shorter hospital stay (-2.6 days [-5.0; -0.1], P=0.038). CONCLUSIONS: Percutaneous axillary access provides similar or better results than surgical access in patients undergoing TAVI with absolute or relative contraindications to femoral access.

Prevalence of Left Ventricular Hypertrophy Caused by Systemic Hypertension Preceding the Development of Severe Aortic Stenosis.

It is generally assumed that left ventricular (LV) hypertrophy in aortic stenosis (AS) is a compensatory adaptation to chronic outflow obstruction. The advent of transcutaneous aortic valve replacement has stimulated more focus on AS in older patients, most of whom have antecedent hypertension. Accordingly, our aim was to investigate the interaction between hypertension and AS on LV remodeling in contemporary practice. We studied consecutive patients referred for echocardiograms with initial aortic valve (AV) peak velocity <3.0 m/s and a peak velocity of >3.5 m/s on a subsequent study performed at least 5 years later. LV size and geometry were measured echocardiographically. Midwall fractional shortening (FSmw) and peak systolic stress were calculated from 2-dimensional echocardiographic and Doppler data. Of 80 patients with progressive AS, 59% were women with mean age 82 ± 9 years. The average interval between the 2 echocardiograms was 5.9 ± 1.8 years. During the study period, peak velocity increased from 2.5 ± 0.4 to 4.2 ± 0.6 m/s (p < 0.01) and LV mass indexed to body surface area increased from 80 ± 28 to 122 ± 51 g/m2 (p < 0.01) with a corresponding shift from normal or concentric LV remodeling geometry to concentric hypertrophy. There was no correlation between change in LV mass index and AV mean gradient or valvulo-arterial impedance. However, change in LV mass index did correlate positively with initial peak velocity and inversely with initial LV mass. Plots of FSmw against circumferential stress at baseline and follow-up suggest that systolic function more than compensates for increasing load in many patients. In conclusion, most patients seen in our practice with severe AS have antecedent hypertension and LV remodeling at a time when outflow obstruction is mild. LV remodeling worsens in parallel with worsening severity of AS. Remodeling in these patients features increasing concentric remodeling of the LV, rather than LV dilation. Systolic function, as assessed by FSmw, remains compensated, or even improves relative to afterload, during progression of AS. Given these findings, we speculate that regression of LV hypertrophy to normal will not be affected by transcutaneous aortic valve replacement because LV hypertrophy preceded hemodynamically severe AS.

Recurrent and Life-Threatening Peripartum Cardiomyopathy: Diagnosis, Delivery Considerations, and Management.

Peripartum cardiomyopathy is an idiopathic reduction in left ventricular systolic function (ejection fraction <45%) toward the end of pregnancy or in the months after delivery. A multidisciplinary approach to management with shock team support is key to identifying and adequately treating patients with refractory heart failure and peripartum cardiomyopathy. (Level of Difficulty: Intermediate.).