Different responses of the myocardial contractility by layer following acute pressure unloading in severe aortic stenosis patients

The present study evaluated change in left ventricle (LV) biomechanics, layer-by-layer, following acute pressure unloading in patients with severe aortic stenosis (AS). In twenty-eight consecutive patients with severe AS who underwent transcatheter aortic valve replacement (TAVR), LV peak global longitudinal and circumferential strains of the endo-, midmyo- and epicardium were evaluated using multilayer speckle tracking echocardiography before, 1 week after, and 1 month after TAVR. Longitudinal and circumferential strains were significantly highest in the endocardium and lowest in the epicardium at baseline. At 1 month following TAVR, longitudinal strain significantly improved in all layers compared with the baseline [endocardium (%) ?16.7 ± 3.8 vs. ?18.6 ± 3.3, P = 0.01; mid-myocardium ?14.4 ± 3.2 vs. ?16.2 ± 3.5, P < 0.01; epicardium ?12.4 ± 2.8 vs. ?13.6 ± 2.6, P = 0.01], whereas LV ejection fraction and circumferential strain remained unchanged. Importantly, only those with LV hypertrophy demonstrated improved longitudinal strain [endocardium (%) ?15.7 ± 3.0 vs. ?18.7 ± 2.9, P < 0.01; mid-myocardium ?13.6 ± 2.7 vs. ?16.0 ± 2.5, P < 0.01; epicardium ?11.8 ± 2.4 vs. ?13.7 ± 2.3, P < 0.01]. The improvement in longitudinal strain was more prominent in the endocardium, which was evident even at an early time point (1 week) after TAVR. Longitudinal strain significantly improved in all three layers following acute pressure unloading, the most prominent of which was observed in the endocardium. Evaluation of multilayer strain may provide new insights into the LV mechanics in the future.     

Noncontrast Myocardial T1 Mapping by Cardiac Magnetic Resonance Predicts Outcome in Patients With Aortic Stenosis

Objectives

The aim of this study was to evaluate whether native T1 value of the myocardium on cardiac magnetic resonance (CMR) could predict clinical events in patients with significant aortic stenosis (AS).

Prognostic Value of Renal Function for Cardiac Events in Patients Without Significant Stenosis on Coronary Computed Tomography Angiography

This study was conducted to determine clinical parameters predicting future major adverse cardiovascular events (MACEs) in patients without significant stenosis on coronary computed tomographic angiography (CCTA). A total of 625 patients with suspected coronary artery disease (CAD) who underwent CCTA that revealed insignificant (< 50%) CAD was reviewed in three cardiac centers. The MACEs including cardiac death, non-fatal myocardial infarction (MI), unstable angina and late (> 90 days after CCTA) revascularization were assessed. During the mean follow-up period of 819 ± 529 days (median 837 days), there were 28 cases of MACEs (4.5%). In multivariable Cox regression analysis, independent predictors for MACEs were male sex (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.01-5.69; P = 0.046) and low estimated creatinine clearance (eCCr) (< 60 mL/min/1.73 m²) (HR, 3.07; 95% CI, 1.22-7.74; P = 0.017). Low eCCr was the only independent predictor for hard events including cardiac death and MI (HR, 17.6, 95% CI, 1.44-215.7; P = 0.025). In conclusion, renal function is an independent predictor for cardiovascular events among patients without significant CAD by CCTA. Careful monitoring and preventive strategy are warranted in patients with impaired renal function even without significant CAD.

Graphical Abstract

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Development of a novel statistical model for mandibular kinematics

The purpose of this study was to establish a new statistical method for the analysis of masticatory function. The subjects were patients with anterior crossbite who had received orthognathic surgery. Chewing movement was measured by means of an opto-electronic motion-analysis system. This movement was compared with similar movement in control patients. We sought to develop a statistical model to predict the population average curves of the chewing cycles. In this study, the mandibular incisor point was used as a target point of jaw movement. The combination of a spline function with random coefficients and self-modeling regression (SEMOR) extended to three dimensions was used to predict population average curves for each group. Unquestionably, significant differences were present in some areas. The present modeling method that uses the combination of a spline function and SEMOR is one of the best ways to eliminate subjective estimation with regard to predicting representative chewing cycles.     

Diagnostic yield of coronary angiography in patients with acute chest pain: role of noninvasive test

Objectives

This study investigated the diagnostic yield of invasive coronary angiography (CAG) and the impact of noninvasive test (NIV) in patients presented to emergency department (ED) with acute chest pain.

Methods

Patients 50 years or older who visited ED with acute chest pain and underwent CAG were identified retrospectively. Those with ischemic electrocardiogram, elevated cardiac enzyme, known coronary artery disease (CAD), history of cardiac surgery, renal failure, or allergy to radiocontrast were excluded. Diagnostic yields of CAG to detect significant CAD or differentiate the need for revascularization were analyzed according to whether NIV was performed and its result.

Results

Among the total 375 consecutive patients, significant CAD was observed in 244 (65.1%). Diagnostic yields of CAG were higher in patients who underwent NIV before CAG, but the discriminative effect was modest (59.7% vs 70.7% [P = .026] for detection of CAD; 45.0% vs 50.5% [P = .285] for revascularization). Positive results of NIV were significantly associated with the presence of CAD and the need for revascularization, when compared with patients without NIV or patients with negative results (P < .001, respectively).

Conclusion

The diagnostic yield of CAG was only 65% in low- to intermediate-risk ED patients with acute chest pain. Performing of NIV provided only modest improvement in diagnostic yield of CAG. The unexpectedly low diagnostic yield might be attributable to the underuse of NIV and misinterpretation of physicians. We suggest the use of NIV as a gatekeeper to discriminate patients who require CAG and/or revascularization, and for this, better risk stratification and appropriate application of NIV are required.     

Change of B-Type Natriuretic Peptide After Surgery and Its Association With Rhythm Status in Patients With Chronic Severe Mitral Regurgitation

Background

B-type natriuretic peptide (BNP) is a useful biomarker of cardiac function in patients with mitral regurgitation (MR). However, the change in BNP in association with rhythm status after corrective surgery has not been studied.

Methods

A total of 101 patients with chronic severe MR undergoing surgery were prospectively enrolled. BNP assays and echocardiographic studies were conducted before and 6 months after surgery. Patients were divided into 3 groups according to pre- and postoperative rhythm (sinus to sinus [SS], n = 61; atrial fibrillation [AF] to sinus [AS], n = 28; AF to AF [AA], n = 12).

Results

BNP decreased only in the AS group 6 months after mitral surgery (from 218.0 ± 136.5 to 94.7 ± 85.1 pg/mL; P < 0.001) but not in the SS or AA groups (P for interaction = 0.001). However, changes of echocardiographic parameters after surgery were not different among the 3 groups. In the AA group, postoperative left ventricular (LV) end-diastolic dimension and left atrial volume were higher than the other groups. Significant determinants of BNP were the presence of AF and the higher pulmonary artery systolic pressure preoperatively (β = 0.767 and P = 0.001 for AF; β = 0.022 and P = 0.019 for pulmonary artery systolic pressure), and the lower LV ejection fraction postoperatively (β = −0.030; P = 0.011).

Conclusions

After surgical correction of chronic organic severe MR, BNP decreased only in patients with preoperative AF which was converted to sinus rhythm postoperatively. A reduction in BNP was not observed when rhythm status did not change. BNP activation was associated with the presence of AF and LV systolic dysfunction, suggesting its prognostic value.