Wall Shear Stress Predicts Aortic Dilation in Patients With Bicuspid Aortic Valve

ObjectivesThis study sought to assess the predictive value of wall shear stress (WSS) for colocalized ascending aorta (AAo) growth rate (GR) in patients with bicuspid aortic valve (BAV).BackgroundBAV is associated with AAo dilation, but there is limited knowledge about possible predictors of aortic dilation in patients with BAV. An increased WSS has been related to aortic wall damage in patients with BAV, but no previous prospective study tested its predictive value for dilation rate. Recently, a registration-based technique for the semiautomatic mapping of aortic GR has been presented and validated.MethodsForty-seven patients with BAV free from valvular dysfunction prospectively underwent 4-dimensional flow cardiac magnetic resonance to compute WSS and subsequent follow-up with 2 electrocardiogram-gated high-resolution contrast-enhanced computed tomography angiograms for GR assessment.ResultsDuring a median follow-up duration of 43 months, mid AAo GR was 0.24 mm/year. WSS and its circumferential component showed statistically significant association with mid AAo GR in bivariate (P = 0.049 and P = 0.014, respectively) and in multivariate analysis corrected for stroke volume and either baseline AAo diameter (P = 0.046 and P = 0.014, respectively) or z-score (P = 0.036 and P = 0.012, respectively). GR mapping further detailed that GR was heterogeneous in the AAo and that circumferential WSS, but not WSS magnitude, showed statistically significant positive associations with GR in the regions with the fastest growth.Conclusions4D flow cardiac magnetic resonance–derived WSS and, in particular, its circumferential component predict progressive dilation of the ascending aorta in patients with BAV. Thus, the assessment of WSS may be considered in the follow-up of these patients.     

Prenatal Diagnosis of a Persistent Fifth Aortic Arch,Pulmonary‐to‐Systemic type: An Unusual Association with Evolving Aortic Coarctation

Persistent fifth arch (PFA) is a rare anomaly that is often underdiagnosed and missed. Different PFA types that have been reported in the literature are systemic‐to‐systemic type (most common), systemic‐to‐pulmonary artery (PA), and PA‐to‐systemic types. The designations of systemic‐to‐PA or PA‐to‐systemic are based on if the PFA is a source of PA or systemic blood flow, respectively, in the setting of critical proximal obstruction (pulmonary atresia or aortic atresia). This case describes an unusual PFA, which connects the distal PA to distal ascending aorta; however, it is not associated with critical proximal obstruction, and while it appeared to be an incidental finding in early gestation, progressive serial distal obstruction of the left fourth arch was seen to develop. This case highlights that prenatal diagnosis of PFA is possible and that once a diagnosis is made, serial fetal echocardiograms should be performed to evaluate for evolving lesions.     

Serum Hepcidin Levels Are Associated With Serum Triglycerides and Interleukin‐6 Concentrations in Patients With End‐Stage Renal Disease

Hepcidin has emerged as a peptide with a key role in the regulation of iron homeostasis in patients with chronic kidney disease (CKD), having a strong dependence on inflammation. Recent studies reveal that hepcidin may be also associated with the progression of atherosclerosis. This study was performed to analyze the relation of hepcidin to markers of atherosclerosis and inflammation in patients on dialysis. A total of 90 individuals were enrolled. Sixty patients with end‐stage renal disease, who were on hemodialysis (HD) (N = 30) and peritoneal dialysis (N = 30) were compared with 30 normal controls (NC). Age, body mass index, time on dialysis, serum lipids, C‐reactive protein (CRP) and interleukin‐6 (IL‐6) were measured and analyzed in correlation with hepcidin concentration. It was found that patients on HD and peritoneal dialysis have significantly higher (P < 0.0001) levels of hepcidin, CRP and IL‐6 than NC. Hepcidin in dialysis patients is significantly related to age (r = 0.373, P = 0.012), serum triglycerides (r = 0.401, P = 0.005), HDL‐C (r = ?0.268, P = 0.048), CRP (r = 0.436, P = 0.0007) and IL‐6 (r = 0.569, P < 0.0001). In multiple regression analysis, hepcidin correlated independently with triglycerides (β = 0.402, P = 0.041) and IL‐6 (β = 0.559, P = 0.006). Moreover, patients with high triglycerides in combination with high IL‐6 levels have significantly increased concentrations of hepcidin than those with low triglycerides and low IL‐6 levels (P < 0.0001). Elevated levels of hepcidin in patients with CKD on dialysis may be related to the occurrence of high triglycerides and high IL‐6 serum concentrations. This probably suggests that hepcidin may play a role to the progression of atherosclerosis and inflammation, but this hypothesis should be further evaluated.     

High Wall Shear Stress Is Related to Atherosclerotic Plaque Rupture in the Aortic Arch of Patients with Cardiovascular Disease: A Study with Computational Fluid Dynamics Model and Non-Obstructive General Angioscopy

Aims: Wall shear stress (WSS) has been considered a major determinant of aortic atherosclerosis. Recently, non-obstructive general angioscopy (NOGA) was developed to visualize various atherosclerotic pathologies, including in vivo ruptured plaque (RP) in the aorta. However, the relationship between aortic RP and WSS distribution within the aortic wall is unclear. This study aimed to investigate the relationship between aortic NOGA-derived RP and the stereographic distribution of WSS by computational fluid dynamics (CFD) modeling using three-dimensional computed tomography (3D-CT) angiography. Methods: We investigated 45 consecutive patients who underwent 3D-CT before coronary angiography and NOGA during coronary angiography. WSS in the aortic arch was measured by CFD analysis based on the finite element method using uniform inlet and outlet flow conditions. Aortic RP was detected by NOGA. Results: Patients with a distinct RP showed a significantly higher maximum WSS value in the aortic arch than those without aortic RP (56.2±30.6 Pa vs 36.2±19.8 Pa, p =0.017), no significant difference was noted in the mean WSS between those with and without aortic RP. In a multivariate logistic regression analysis, the presence of a maximum WSS value more than a specific value was a significant predictor of aortic RP (odds ratio 7.21, 95% confidence interval 1.78-37.1, p =0.005). Conclusions: Aortic RP detected by NOGA was strongly associated with a higher maximum WSS in the aortic arch derived by CFD using 3D-CT. The maximum WSS value may have an important role in the underlying mechanism of not only aortic atherosclerosis, but also aortic RP.     

Usefulness of Parameters of Left Ventricular Wall Stress and Systolic Function in the Evaluation of Patients with Aortic Stenosis

Left ventricular function and myocardial contractility in aortic stenosis have been intensely studied over the past 40 years. The underlying impetus for a good deal of this work has been to define the interaction between the ventricle and the valve, to predict in an individual patient the clinical course and outcome after aortic valve replacement. Furthermore, the relationship between afterload (wall stress) and contractility has been closely examined. Although wall stress has been shown to be inversely correlated to ejection fraction or fiber shortening, there is wide individual variability for a similar degree of valvular stenosis, which renders interpretation of data regarding left ventricular function and myocardial contractility difficult. A number of other factors affect the response of the left ventricle to chronic pressure overload. The use of stress-shortening relationships in patients with aortic stenosis requires further study before these measures can be advocated for clinical use. This review examines the usefulness of left ventricular wall stress and parameters of left ventricular function in aortic stenosis, dealing with basic concepts, echocardiographic approach, and clinical usefulness.     

Increased P‐Wave Duration and P‐Wave Dispersion in Patients with Aortic Stenosis

Background: P‐wave dispersion (PWD), defined as the difference between the maximum and minimum P‐wave duration, has been proposed as being useful for the prediction of paroxysmal atrial fibrillation (AF). AF is the most common arrhythmia and an important prognostic indicator for clinical deterioration in patients with aortic stenosis (AS). The aim of the present study was to evaluate PWD in patients with AS. Methods: The study population consisted of two groups: Group I consisted of 98 patients with AS (76 men, 22 women; aged 63 ± 8 years) and group II consisted of 98 healthy subjects (same age and sex) without any cardiovascular disease. A 12‐lead electrocardiogram was recorded for each subject. The P‐wave duration was calculated in all leads of the surface electrocardiogram. The difference between the maximum and minimum P‐wave duration was calculated and was defined as the PWD. All patients and control subjects were also evaluated by echocardiography to measure the left atrial diameter, left ventricular ejection fraction, left ventricular wall thicknesses, and the maximum and mean aortic gradients. Patients were also evaluated for the presence of paroxysmal AF. Results: Maximum P‐wave duration and PWD of group I were found to be significantly higher than those of group II. In addition, patients with paroxysmal AF had significantly higher PWD than those without paroxysmal AF. There was no significant difference between the two groups regarding minimum P‐wave duration. In addition, there was no significant correlation between echocardiographic variables and PWD. Conclusion: PWD, indicating increased risk for paroxysmal AF, was found to be significantly higher in patients with AS than in those without it. Further assessment of the clinical utility of PWD for the prediction of paroxysmal AF in patients with severe AS will require longer prospective studies.     

Erectile Dysfunction in High‐Risk Hypertensive Patients Treated with Beta‐Blockade Agents

Background: Erectile dysfunction (ED) is a multifactorial disease related to age, vascular disease, psychological disorders, or medical treatments. Beta‐blockade agents are the recommended treatment for hypertensive patients with some specific organ damage but have been outlined as one of leading causes of drug‐related ED, although differences between beta‐blockade agents have not been assessed. Methods: Cross‐sectional and observational study of hypertensive male subjects treated with any beta‐blockade agent for at least 6 months. ED dysfunction was assessed by the International Index of Erectile Dysfunction (IIEF). Results: 1.007 patients, mean age 57.9 (10.59) years, were included. The prevalence of any category of ED was 71.0% (38.1% mild ED; 16.8% moderate ED; 16.1% severe ED). Patients with ED had longer time since the diagnosis of hypertension and higher prevalence of risk factors and comorbidities. The prevalence of ED increased linearly with age. ED patients received more medications and were more frequently treated with carvedilol and less frequently with nebivolol. Patients treated with nebivolol obtained higher scores in every parameter of the IIEF questionnaire. The multivariate analysis identified independent associations between ED and coronary heart disease (OR: 1.57), depression (OR: 2.25), diabetes (OR: 2.27), atrial fibrillation (OR: 2.59), and dyhidopiridines calcium channel blockers (OR: 1.76); treatment with nebivolol was associated to lower prevalence of ED (OR: 0.27). Conclusion: ED is highly prevalent in hypertensive patients treated with beta‐blockade agents. The presence of ED is associated with more extended organ damage and not to cardiovascular treatments, except for the lower prevalence in nebivolol‐treated patients.     

Prognostic Significance of T‐Wave Amplitude in Lead aVR on the Admission Electrocardiography in Patients with Anterior Wall ST‐Elevation Myocardial Infarction Treated by Primary Percutaneous Intervention

Background: T‐wave positivity in aVR lead patients with heart failure and anterior wall old ST‐segment elevation myocardial infarction (STEMI) are shown to have a higher frequency of cardiovascular mortality, although the effects on patients with STEMI treated with primary percutaneous coronary intervention (PCI) has not been investigated. In this study, we sought to determine the prognostic value of T wave in lead aVR on admission electrocardiography (ECG) for in‐hospital mortality in patients with anterior wall STEMI treated with primary PCI. Methods: After exclusion, 169 consecutive patients with anterior wall STEMI (mean age: 55 ± 12.9 years; 145 men) undergoing primary PCI were prospectively enrolled in this study. Patients were classified as a T‐wave positive (n = 53, group 1) or T‐wave negative (n = 116, group 2) in aVR based upon the admission ECG. All patients were evaluated with respect to clinical features, primary PCI findings, and in‐hospital clinical results. Results: T‐wave positive patients who received primary PCI were older, multivessel disease was significantly more frequent and the duration of the patient's hospital stay was longer than T‐wave negative patients. In‐hospital mortality tended to be higher in the group 1 when compared with group 2 (7.5% vs 1.7% respectively, P = 0.05). After adjusting the baseline characteristics, positive T wave remained an independent predictor of in hospital mortality (odds ratio: 4.41; 95% confidence interval 1.2–22.1, P = 0.05). Conclusions: T‐wave positivity in lead aVR among patients with an anterior wall STEMI treated with primary PCI is associated with an increase in hospital cardiovascular mortality.     

Recovery of Long‐Axis Left Ventricular Function after Aortic Valve Replacement in Patients with Severe Aortic Stenosis

Background: Patients with aortic stenosis (AS) should undergo aortic valve replacement (AVR) before irreversible LV dysfunction has developed. Assessment of long‐axis left ventricular (LV) function may assist in proper timing of AVR. Objectives: To assess serial changes in long‐axis LV function before and after AVR in patients with severe AS and preserved LV ejection fraction. Methods: The study comprised 27 consecutive patients (mean age 64.9 ± 11.7 years, 15 males) with symptomatic severe AS, scheduled for AVR. Seventeen subjects without known cardiac disease, matched for age, gender, LV ejection fraction and cardiovascular risk factors, served as a control group. Long‐axis LV function assessment was done with tissue Doppler imaging at 3 weeks, 6 months, and 12 months after AVR. Results: Mean aortic valve area in the AS group was 0.70 ± 0.24 cm². Pre‐AVR peak systolic mitral annular velocities were significantly lower compared to controls (6.7 ± 1.5 vs. 8.9 ± 2.0 cm/s, P < 0.05). Post‐AVR peak systolic mitral annular velocities improved to 9.1 ± 2.9 at 3 weeks, 8.6 ± 2.7 at 6 months, and 8.1 ± 1.7 cm/s at 12 months (P < 0.05). Improvements were seen over the whole range of pre‐AVR peak systolic mitral annular velocities. Patients with improved Sm after AVR (defined as ≥10% compared to baseline values) did not differ in baseline characteristics as compared to those who did not improve. Conclusions: In patients with severe AS and preserved LV ejection fraction, abnormal systolic mitral annular velocities improve after AVR, independent of the pre‐AVR value. (Echocardiography 2010;27:1177‐1181)     

The Correlation between Three‐Dimensional Vena Contracta Area and Aortic Regurgitation Index in Patients with Aortic Regurgitation

Objectives: The aims of this study are to explore the correlation between the three‐dimensional vena contracta (3D VC) area and the aortic regurgitation (AR) index and to determine AR severity using the 3D VC area. Background: The geometry of regurgitant jets is complex in patients with AR. The 3D VC area can be easily cropped using any plane and we can obtain the complex geometry of the VC area. Methods: Full‐volume three‐dimensional (3D) color flow datasets were generated using the trans‐thoracic parasternal approach. The AR jet could be well visualized and analyzed in three orthogonal planes using dedicated software. Results: We consecutively analyzed 77 AR patients with comprehensive 2D and 3D echocardiographic data. The 3D VC area increased proportionately with increasing AR severity using the AR index method (F = 86.1, P < 0.001) and correlated well with effective regurgitant orifice (P < 0.001). The cutoff value of the VC area was < 30 mm² (sensitivity = 90% and specificity = 88%) for predicting mild AR and > 50 mm² (sensitivity = 92% and specificity = 87%) for predicting severe AR. Conclusion: 3D color flow VC area measurement provides a simple and accurate method for assessing the severity of AR. (ECHOCARDIOGRAPHY 2010;27:161‐166)     

Effect of Hemodialysis on the Red Blood Cell Life Span in Patients with End‐Stage Kidney Disease

The aim of this study was to use a CO breath test to investigate hemodialysis effects on red blood cell lifespan in patients with chronic kidney disease. A cohort of 17 non‐smoking men with end‐stage kidney disease undergoing hemodialysis via a polysulfone dialysis membrane (as opposed to a traditional cellulose acetate membrane) were subjected to a repeated Levitt's CO breath test to compare red blood cell lifespan before vs. after dialysis. None of the patients showed significant fluctuations in endogenous CO concentration during the dialysis procedure. The mean red blood cell lifespan was 66.0 ± 31.0 days before dialysis and 72.0 ± 26.0 days after dialysis, with no significant difference between the assessment time points (P > 0.05). In conclusion, dialysis using a polysulfone membrane did not appear to disrupt red blood cells or reduce their lifespan in patients with end‐stage kidney disease.