Postoperative atrial fibrillation after aortic valve replacement is a risk factor for long-term atrial fibrillation.

OBJECTIVES: Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. However, knowledge on the rate of long-term atrial fibrillation (LTAF) after POAF remains unclear. We investigated predictors of POAF in patients with aortic stenosis undergoing surgical aortic valve replacement, and assessed the rate of LTAF during follow-up. METHODS: We prospectively included 96 adult patients with severe aortic stenosis undergoing surgical aortic valve replacement. Patients with previous atrial fibrillation (AF) were excluded. Patients underwent echocardiography, cardiac computed tomography and magnetic resonance imaging immediately prior to surgery. Surgical aortic clamp time and postoperative C-reactive protein (CRP) were documented. POAF was defined as AF recorded within 7 days of surgery. Through chart review, patients were followed up for documented episodes of LTAF occurring more than 7 days after surgery. RESULTS: POAF occurred in 51 patients (53%). It was associated with larger preoperative echocardiographic left atrial volume index (44 ± 12 vs 37 ± 8 ml/m2, P = 0.004), longer aortic clamp time [80 (70-102) vs 72 (62-65) min, P = 0.04] and higher CRP on first postoperative day [80 (64-87) vs 65 (44-83) mg/l, P = 0.001]. Multivariable logistic regression revealed that left atrial volume index [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.02-1.13; P = 0.005] and postoperative CRP (OR 1.03, 95% CI 1.01-1.05; P = 0.006) were the only independent predictors of POAF. During 695 days (25th-75th percentile: 498-859 days) of follow-up, LTAF occurred in 11 patients of whom 10 were in the POAF group (hazard ratio 9.4, 95% CI 1.2-74; P = 0.03). CONCLUSIONS: POAF is predicted by left atrial volume index and postoperative CRP. Patients with POAF have a 9-fold increase risk of developing symptomatic LTAF during follow-up. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT02316587).

Children centered care: Minimizing the need for anesthesia with a multi-faceted concept for MRI in children aged 4-6.

PURPOSE: To evaluate the need for general anesthesia (GA) in MRI in children aged 4-6 years, using a multi-faceted concept, Children Centered Care (CCC), compared to a standard setup. MATERIALS AND METHODS: In this prospective study of 81 children, we developed and tested a multi-faceted concept, CCC, for MRI in children aged 4-6 without GA, comparing it to a standard setup. The CCC included: 1) an interactive app, 2) a trained pediatric team, 3) a children's lounge with a toy-scanner, and 4) a child-friendly multimedia environment in the MRI room. Patients were included from February-September 2016 and 2017. The use of GA was evaluated, image quality was assessed and a cost-benefit analysis was done. RESULTS: We included 40 children in the control group and 41 in the CCC group. Mean age was 5.8 years and 48 (59%) were males. Neuro and orthopedic imaging accounted for 58 (72%) and 22 (27%), respectively. With the CCC setup 39/41 (95%) completed a diagnostic MRI without GA compared to 17/40 (43%) in the control group (p < 0.001). Image quality was not different between the groups (p = 0.37). The setup proved cost-effective with a payback time of two years in a Danish setting with 250 eligible patients per year. CONCLUSION: With the multi-faceted concept CCC, the use of GA for MRI in children aged 4-6 was markedly reduced to 5%, image quality was maintained and the setup was cost-effective.

Exercise Hemodynamics After Aortic Valve Replacement for Severe Aortic Stenosis.

BACKGROUND: Severe aortic stenosis (AS) is often accompanied by diastolic dysfunction. After aortic valve replacement (AVR), the left ventricle often undergoes considerable reverse remodeling. Despite this, diastolic dysfunction may persist after AVR. The aims of this study were to determine the incidence of elevated left ventricular (LV) filling pressure at rest and during exercise among patients with severe AS after AVR and to describe factors related to elevated LV filling pressure, especially its association with LV and left atrial remodeling and myocardial fibrosis. METHODS: Thirty-seven patients undergoing AVR were included. Echocardiography, cardiac computed tomography, and magnetic resonance imaging were performed before AVR. An LV biopsy sample was obtained during AVR and analyzed for collagen fraction. One year after AVR, right heart catheterization with exercise was performed. A mean pulmonary capillary wedge pressure (PCWP) ≥ 28 mm Hg during exercise was considered elevated. RESULTS: Twelve patients (32%) had elevated exercise PCWP 1 year after AVR. Exercise PCWP was highest among patients undergoing concomitant coronary artery bypass graft surgery (30 ± 7 vs 25 ± 6 mm Hg, P = .04) and among patients with preoperative stroke volume index < 35 mL/m2 (28 ± 8 vs 23 ± 4 mm Hg, P < .05). Baseline LV ejection fraction was lower among patients with elevated PCWP (56 ± 8% vs 64 ± 8%, P = .01), and coronary calcium score was significantly higher (median 870 AU [interquartile range, 454-2,491 AU] vs 179 AU [interquartile range, 63-513 AU], P = .02). Conversely, exercise PCWP was not related to the presence of high LV wall mass or to the severity of AS. Among patients undergoing isolated AVR, there was a correlation between LV interstitial volume fraction and PCWP (r = 0.57, P = .01) and mean pulmonary artery pressure (r = 0.51, P = .03) during exercise. CONCLUSIONS: Elevated filling pressure during exercise was seen in one third of patients after AVR in this population and was seen primarily among patients with coexisting ischemic heart disease or diffuse myocardial fibrosis but was unrelated to preoperative severity of AS and LV remodeling.

Hemodynamic Characteristics in Significant Symptomatic and Asymptomatic Primary Mitral Valve Regurgitation at Rest and During Exercise.

BACKGROUND: In severe asymptomatic primary mitral valve regurgitation without risk factors, surgery strategy is controversial. We sought to clarify whether being symptomatic corresponds to the hemodynamic burden and reduced exercise capacity. A better understanding of this may contribute to optimize timing of surgery. METHODS AND RESULTS: Subjects with asymptomatic (New York Heart Association functional class I, n=29) or symptomatic (New York Heart Association functional class II and III, n=28) significant primary mitral valve regurgitation (effective regurgitant orifice, ≥0.30 cm2; left ventricular ejection fraction, >60%) were included. Right heart catheterization during rest and exercise, echocardiography, magnetic resonance imaging, and peak oxygen consumption test was performed. Symptomatic subjects had significantly higher pulmonary capillary wedge pressure at rest (14±4 versus 11±3 mm Hg; P=0.003) and at maximal exercise (30±6 versus 25±7 mm Hg; P=0.02) and higher mean pulmonary artery pressure (PAP) at rest (22±7 versus 18±4 mm Hg; P=0.005) and maximal exercise (46±8 versus 39±7 mm Hg; P=0.005) than asymptomatic subjects. Among asymptomatic subjects with normal resting value, exercise testing revealed a systolic PAP >60 mm Hg in 34%. Also the reverse response with minimal increase in pulmonary capillary wedge pressure and mean PAP during exercise was seen, especially in asymptomatic subjects. Among symptomatic subjects, we found a significant inverse correlation between resting mean PAP and left ventricular ejection fraction (r=-0.52; P=0.02) and right ventricular ejection fraction (r=-0.67; P<0.01). Peak oxygen consumption was equal and normal in both groups and correlated with left ventricular stroke volume but not with pulmonary capillary wedge pressure. CONCLUSIONS: Symptoms in patients with severe mitral valve regurgitation relate to congestion (pulmonary capillary wedge pressure and PAP), but not to peak oxygen consumption, which is determined by forward left ventricular stroke volume. Exercise testing reveals a higher mitral valve regurgitation burden in apparently asymptomatic patients. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02961647.

Layer-specific deformation analysis in severe aortic valve stenosis, primary mitral valve regurgitation, and healthy individuals validated against invasive hemodynamic measurements of heart function.

AIM: Speckle tracking echocardiography is considered valuable in assessing left ventricular (LV) function. The method has been refined to assess deformation in different myocardial layers, but the effect of volume vs pressure overload on this pattern is unknown. The aim was to test whether layer-specific myocardial strain (LSS) obtained by speckle tracking echocardiography exhibits different patterns in conditions with different loading conditions. METHODS AND RESULTS: Forty patients with asymptomatic severe aortic stenosis (AS) (AVA 0.81 ± 0.15 cm2 , LV ejection fraction [LVEF] 66% ± 7%), 43 patients with asymptomatic or mildly symptomatic significant primary mitral regurgitation (MR) (effective regurgitant orifice (ERO) 0.51 (IQR 0.37-0.67) cm2 , LVEF 70% ± 7%), and 23 healthy individuals (LVEF 65% ± 6%) were enrolled. Echocardiography and right heart catheterization were performed in all patients. In MR, strain values in each myocardial layer (endocardial/global longitudinal strain (GLS)/epicardial) were higher (25.0% ± 3.4%/21.6% ± 2.9%/18.8% ± 2.6%) compared to healthy individuals (22.6% ± 3.2%/19.6% ± 2.9%/17.1% ± 2.6%) and AS (20.5% ± 2.8%/17.7% ± 2.5%/14.0% ± 5.6%), P < .001. All 3 groups exhibited a similar LSS pattern with highest values in the endocardial and lowest values in the epicardial layer. The epicardial-endocardial strain ratio was lower in AS (0.72 ± 0.04) than in MR (0.75 ± 0.04, P = .04). Global longitudinal strain (GLS) correlated significantly with LV wall stress (r = .39, P = .0003) but not with LV stroke work or contractility. CONCLUSION: Layer-specific myocardial strain (LSS) patterns differed in patients with severe AS, significant MR, and healthy individuals with highest values in MR. Strain irrespective of layer assessed was associated with LV wall stress but seemed less related to contractility and unrelated to stroke work in the setting of normal LVEF.

Postoperative Reverse Remodeling and Symptomatic Improvement in Normal-Flow Low-Gradient Aortic Stenosis After Aortic Valve Replacement.

BACKGROUND: Severe aortic stenosis (AS) most often presents with reduced aortic valve area (<1 cm2), normal stroke volume index (≥35 mL/m2), and either high mean gradient (≥40 mm Hg; normal-flow high-gradient AS) or low mean gradient (normal-flow low-gradient [NFLG] AS). The benefit of aortic valve replacement (AVR) among NFLG patients is controversial. We compared the impact of NFLG condition on preoperative left ventricular (LV) remodeling and myocardial fibrosis and postoperative remodeling and symptomatic benefit. METHODS AND RESULTS: Eighty-seven consecutive patients with reduced aortic valve area and normal stroke volume index undergoing AVR underwent echocardiography, magnetic resonance imaging, a 6-minute walk test, and measurement of natriuretic peptides before and 1 year after AVR. Myocardial fibrosis was assessed from magnetic resonance imaging. Patients were stratified as NFLG or normal-flow high-gradient. In total, 33 patients (38%) had NFLG. Before AVR, they were characterized by similar symptom burden but less severe AS measured by aortic valve area index (0.50±0.09 versus 0.40±0.08 cm2/m2; P<0.0001), lower LV mass index (74±18 versus 90±26 g/m2; P=0.01), but the same degree of myocardial fibrosis. After AVR, NFLG had a smaller reduction in LV mass index (-3±10 versus -±18 g/m2; P<0.0001) and a smaller reduction in natriuretic peptides. Both groups experienced similar symptomatic improvement. Normal-flow high-gradient condition independently predicted change in LV mass index. CONCLUSIONS: Patients with NFLG had less severe AS and LV remodeling than patients with normal-flow high-gradient. Furthermore, NFLG patients experienced less reverse remodeling but the same symptomatic benefit. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02316587.

Left ventricular diastolic function is associated with symptom status in severe aortic valve stenosis.

BACKGROUND: In aortic valve stenosis (AS), the occurrence of heart failure symptoms does not always correlate with severity of valve stenosis and left ventricular (LV) function. Therefore, we tested the hypothesis that symptomatic patients with AS have impaired diastolic, longitudinal systolic function, and left atrial dilatation compared with asymptomatic patients. METHODS AND RESULTS: In a retrospective descriptive study, we compared clinical characteristics and echocardiographic parameters in 99 symptomatic and 139 asymptomatic patients with severe AS and LV ejection fraction ≥50%. Independent predictors of symptomatic state were identified using logistic regression analysis. Symptomatic patients were younger (72±10 versus 76±12 years of age; P=0.002), presented less often with atrial fibrillation (13% versus 24%; P=0.05) and chronic obstructive pulmonary disease (2% versus 19%; P<0.001), and had a lower prevalence of hypertension (73% versus 40%; P<0.001). Despite similar AS severity, symptomatic patients had higher LV mass index (120±39 versus 95±25 g/m2; P<0.0001), increased relative wall thickness (0.61±0.15 versus 0.50±0.11; P<0.0001), shorter mitral deceleration time (199±58 versus 268±62 ms; P<0.0001), and increased left atrial volume index (49±18 versus 42±15 mL/m2; P=0.02). When adjusting for age, history of hypertension, atrial fibrillation, and chronic obstructive pulmonary disease in a multivariable logistic regression analysis, LV mass index, relative wall thickness, left atrial volume index, and deceleration time were still associated with the presence of symptoms. CONCLUSIONS: The present study demonstrates that symptomatic status in severe AS is associated with impaired diastolic function, LV hypertrophy, concentric remodeling, and left atrial dilatation when corrected for indices of AS severity. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00294775.

Relation of osteoprotegerin in severe aortic valve stenosis to postoperative outcome and left ventricular function.

Osteoprotegerin (OPG) is a member of the tumor necrosis factor receptor superfamily and is known to be among the mediators of the calcification process that has been shown to increase in patients with aortic stenosis (AS). The aim of this study was to characterize the association of OPG with left ventricular (LV) function and remodeling and to evaluate the significance of preoperative OPG on long-term outcome in terms of survival and symptomatic improvement in 124 patients with severe AS scheduled for aortic valve replacement (AVR). Patients were divided according to tertiles of preoperative OPG. Preoperative OPG was associated with age, EuroSCORE, and preoperative functional capacity. Despite similar ejection fraction and diastolic function among groups, longitudinal LV systolic function consistently decreased and markers of filling pressure increased across groups. During median follow-up of 4 years, 41 patients died of a presumed cardiovascular cause or remained in New York Heart Association functional class III or IV. The risk of a poor postoperative outcome after AVR increased with increasing OPG tertiles (15% vs 33% vs 51%, p = 0.002). In a multivariate model containing age, ejection fraction, N-terminal pro-brain natriuretic peptide and left atrial volume index, OPG was still significantly associated with postoperative outcome. In addition, OPG levels associated with cardiovascular mortality during follow-up. In conclusion, OPG is associated with LV and left atrial remodeling in patients with symptomatic severe AS undergoing AVR. Moreover, plasma OPG is associated with long-term postoperative outcome and may identify patients with poor symptomatic improvement after surgery.