Citations

Low-flow, low-gradient (LF/LG) severe aortic stenosis (AS) with preserved ejection fraction refers to the condition of AS with aortic valve area ≤1 cm2, stroke volume index <35 mL/m2, mean aortic valve gradient <40 mm Hg and left ventricular ejection fraction ≥50%. This mismatch of aortic valve area suggesting severe stenosis and ‘low’ gradient in some patients has led to confusion as to the severity of stenosis. Conditions previously labelled as LF/LG severe AS include a spectrum, with measurement error probably being the most common cause of marked inconsistency between gradient, valve area and patient presentation. The presence of LG severe AS may be overestimated in petite patients, who may have aortic valve area slightly less than 1 cm2 with only moderate AS. Concomitant cardiac conditions besides AS, including significant mitral and tricuspid regurgitation, intracardiac shunts and constrictive pericarditis, may contribute to reduced stroke volume, and evidence for these must be sought at the time of echocardiography. True LF/LG severe AS is associated with a unique and probably maladaptive remodelling pattern with smaller ventricles, increasing relative wall thickness, progressive worsening of diastolic function and higher afterload, as demonstrated by lower systemic arterial compliance, higher systemic vascular resistance and higher valvuloarterial impedance. Control of hypertension is essential to the appropriate management of patients with AS. Aortic valve replacement should be considered in patients with compelling evidence of severe AS who remain symptomatic despite optimal treatment of hypertension.

Background— Quadricuspid aortic valve (QAV) is a rare congenital cardiac defect. This study sought to determine QAV frequency in a large echocardiography database, to characterize associated cardiovascular abnormalities, and to describe long-term outcomes. Methods and Results— Fifty patients (mean±SD age, 43.5±21.8 years at the time of the index diagnosis; female sex, 52%) received a diagnosis of QAV between January 1, 1975, and March 14, 2014 (frequency, 0.006%). The QAV was type A in 32% and type B in 32% (Hurwitz and Roberts classification). Aortic dilatation was present in 29% of the patients, and 26% had moderate or severe aortic valve regurgitation at the index diagnosis. Stenosis affected only 8% of the valves and was mild. Other findings, including abnormalities of other cardiac valves, septal defects, persistent left superior vena cava, and patent ductus arteriosus, were present in 32% of patients. During a mean±SD follow-up of 4.8±5.6 years, 8 patients underwent aortic valve surgery, with severe aortic valve regurgitation being the surgical indication in 7 patients. One patient with mild to moderate aortic valve regurgitation underwent aortic valve repair for obstruction of the left coronary ostium by the accessory cusp of QAV. No infective endocarditis or aortic dissection was found. Overall survival was 91.5% and 87.7% at 5 and 10 years. Conclusions— Aortic dilatation and other structural cardiac abnormalities were relatively common among patients with QAV. Aortic valve regurgitation was the predominant hemodynamic abnormality and the indication for aortic valve surgery in most patients who received surgery. Long-term survival was excellent.

Background— In asymptomatic patients with severe aortic stenosis, guidelines recommend left ventricular ejection fraction (LVEF) of <50% as the threshold for referral for aortic valve replacement. We investigated the importance of LVEF on long-term outcome after aortic valve replacement in symptomatic and asymptomatic patients with severe aortic stenosis. Methods and Results— We retrospectively identified 2017 patients with severe aortic stenosis (aortic valve area<1 cm 2 , mean gradient≥40 mm Hg, or indexed aortic valve area<0.6 cm 2 /m 2 ) who underwent surgical aortic valve replacement from January 1995 to June 2009. Patients were divided into 4 groups depending on preoperative LVEF (<50% in 300 [15%] patients, 50%–59% in 331 [17%], 60%–69% in 908 [45%], and ≥70% in 478 [24%]). During follow-up of 5.3±4.4 years, 1056 (52%) patients died. A decrease in mortality was observed with increasing LVEF, P <0.0001; 5-year mortality estimates (95% confidence interval) were 0.41 (0.35–0.47), LVEF<50%; 0.35 (0.29–0.41), LVEF 50% to 59%; 0.26 (0.23–0.29), LVEF 60% to 69%; and 0.22 (0.18–0.26), LVEF≥70%. Compared with patients with LVEF≥60%, patients with LVEF 50% to 59% had increased mortality (hazard ratio [HR], 1.58; P <0.001), with similar risk increase in both symptomatic (HR, 1.56; P <0.001) and asymptomatic patients (HR, 1.58; P =0.006). Correcting for risk factors, LV mass index, aortic valve area, and stroke volume index, LVEF was independently predictive of mortality (HR, 0.88 per 10%; P <0.001). When this analysis was repeated in the subset of 1333 patients without history of coronary artery disease, LVEF remained associated with mortality (HR, 0.90 per 10%; P =0.009). Conclusions— LVEF is a powerful predictor of outcome in patients with severe aortic stenosis undergoing aortic valve replacement, independent of the presence of valve-related symptoms.

Background Myocardial strain imaging is a sensitive echocardiographic technique for identifying ventricular dysfunction. The aim of this study was to describe a reference range for right ventricular ( RV ) strain in subjects without cardiopulmonary disease and to report these values from a systematic review and meta‐analysis of the current literature. Methods Prospective online measurement of RV free wall longitudinal systolic strain using speckle tracking echocardiography ( STE ) was performed in 116 subjects with normal echocardiograms and without cardiopulmonary disease or risk factors. A systematic search of studies in EMBASE and Medline reporting RV strain values was performed through February 2014. Results The mean age was 48 ± 16 years and 58% were female. Mean RV strain was −26 ± 4%. Ten studies involving a total of 486 patients met our inclusion criteria. The mean age range was 43–57 years and 59% were female. All prior studies were performed with offline strain analysis, and 9 used a GE Healthcare strain analysis software system. The weighted estimate of RV free wall strain measured using tissue Doppler imaging (4 studies) was −27 ± 1% (95% confidence interval [ CI ] −30% to −25%) and with STE (8 studies, including the current study data) −27 ± 2% (95% CI −29% to −24%), respectively. Conclusions A reference range for RV strain in subjects without cardiopulmonary disease is presented. These data may help facilitate the routine clinical measurement of RV strain in patients referred for right heart echocardiography assessment.

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/m 2 ; 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/m 2 ; 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.

Background— Among patients with severe aortic stenosis (AS) and preserved ejection fraction, those with low gradient (LG) and reduced stroke volume may have an adverse prognosis. We investigated the prognostic impact of stroke volume using the recently proposed flow-gradient classification. Methods and Results— We examined 1704 consecutive patients with severe AS (aortic valve area <1.0 cm 2 ) and preserved ejection fraction (≥50%) using 2-dimensional and Doppler echocardiography. Patients were stratified by stroke volume index (<35 mL/m 2 [low flow, LF] versus ≥35 mL/m 2 [normal flow, NF]) and aortic gradient (<40 mm Hg [LG] versus ≥40 mm Hg [high gradient, HG]) into 4 groups: NF/HG, NF/LG, LF/HG, and LF/LG. NF/LG (n=352, 21%), was associated with favorable survival with medical management (2-year estimate, 82% versus 67% in NF/HG; P <0.0001). LF/LG severe AS (n=53, 3%) was characterized by lower ejection fraction, more prevalent atrial fibrillation and heart failure, reduced arterial compliance, and reduced survival (2-year estimate, 60% versus 82% in NF/HG; P <0.001). In multivariable analysis, the LF/LG pattern was the strongest predictor of mortality (hazard ratio, 3.26; 95% confidence interval, 1.71–6.22; P <0.001 versus NF/LG). Aortic valve replacement was associated with a 69% mortality reduction (hazard ratio, 0.31; 95% confidence interval, 0.25–0.39; P <0.0001) in LF/LG and NF/HG, with no survival benefit associated with aortic valve replacement in NF/LG and LF/HG. Conclusions— NF/LG severe AS with preserved ejection fraction exhibits favorable survival with medical management, and the impact of aortic valve replacement on survival was neutral. LF/LG severe AS is characterized by a high prevalence of atrial fibrillation, heart failure, and reduced survival, and aortic valve replacement was associated with improved survival. These findings have implications for the evaluation and subsequent management of AS severity.