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).

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.