The Prognostic Value of Left Atrial Global Longitudinal Strain and Left Atrial Phasic Volumes in Patients Undergoing Transcatheter Valve Implantation for Severe Aortic Stenosis.

INTRODUCTION: The changes and the prognostic implications of left atrial (LA) volumes (LAV), LA function, and vascular load in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) are less known. METHODS: We enrolled 150 symptomatic patients (mean age 82 ± 8 years, 58% female, and pre-TAVI aortic valve area 0.40 ± 0.19 cm/m2) with severe AS who underwent 2D transthoracic echocardiography and 2D speckle tracking echocardiography at average 21 ± 35 days before and 171 ± 217 days after TAVI. The end point was a composite of new onset of atrial fibrillation, hospitalization for heart failure and all-cause death (major adverse cardiac events [MACE]). RESULTS: After TAVI, indexed maximal LA volume and minimum volume of the LA decreased by 2.1 ± 10 mL/m2 and 1.6 ± 7 mL/m2 (p = 0.032 and p = 0.011, respectively), LA function index increased by 6.8 ± 11 units (p < 0.001), and LA stiffness decreased by 0.38 ± 2.0 (p = 0.05). No other changes in the LA phasic volumes, emptying fractions, and vascular load were noted. Post-TAVI, both left atrial and ventricular global peak longitudinal strain improved by about 6% (p = 0.01 and 0.02, respectively). MACE was reached by 37 (25%) patients after a median follow-up period of 172 days (interquartile range, 20-727). In multivariable models, MACE was associated with both pre- and post-TAVI LA global peak longitudinal strain (hazard ratio [HR] 0.75, CI 0.59-0.97; and HR 0.77, CI 0.60-1.00, per 5 percentage point units, respectively), pre-TAVI LV global endocardial longitudinal strain (HR 1.37, CI 1.02-1.83 per 5 percentage point units), and with most of the LA phasic volumes. CONCLUSION: Within 6 months after TAVI, there is reverse LA remodeling and an improvement in LA reservoir function. Pre- and post-TAVI indices of LA function and volume remain independently associated with MACE. Larger studies enrolling a greater diversity of patients may provide sufficient evidence for the utilization of these imaging biomarkers in clinical practice.

The Association between Aortic Valve Weight, Echocardiographic Indices, and All-Cause Death in 1,046 Patients Undergoing Surgical Aortic Valve Replacement for Aortic Stenosis.

BACKGROUND: Aortic valve weight (AVW), a flow independent measure of aortic stenosis (AS) severity, is reported to have heterogeneous associations with the echocardiographic variables used for AS evaluation. Controversy exists regarding its impact on survival after aortic valve replacement (AVR). OBJECTIVE: We sought to determine the association between AVW with echocardiographic measures of AS severity and all-cause mortality after surgical AVR. METHODS: One thousand and forty-sixconsecutive patients underwent surgical AVR for AS, the excised valves were weighed, and an echocardiogram was done before surgery. RESULTS: Males had heavier valves than females, for both absolute and body surface are (BSA)-indexed values (2.78 ± 1.23 vs. 2.08 ± 0.68 g, p < 0.001; and 1.38 ± 0.61 vs. 1.19 ± 0.41 g/m2, p < 0.001, respectively). In a restricted cohort of 634 patients with isolated severe AS and normal ejection fraction, the correlations of AVW with echocardiographic variables of AS were modest, the strongest being with the dimensionless index (r = -0.27 and -0.26 for male and female, both p < 0.01). Stratified by stroke volume index and mean gradient (MG), no associations were found in the low-gradient groups (i.e., MG <40 mmHg). At a median follow-up of 3.5 years, there were only 244 deaths in the entire cohort. Mortality was not related to AVW, except in females who displayed an inverse relationship (HR = 0.67; 95% CI 0.47-0.95) only when it was analyzed as a continuous variable. CONCLUSIONS: The weak correlation between AVW with the echocardiographic indices of AS may reflect its complex pathophysiology, heterogeneous hemodynamics, and possible pitfalls in the current echocardiographic methods used in clinical practice. The prognostic value of AVW after AVR warrants further evaluation.

The Utility of Flow Rate Compared with Left Ventricular Stroke Volume Index in the Hemodynamic Classification of Severe Aortic Stenosis with Preserved Ejection Fraction.

OBJECTIVES: To substitute the stroke volume index (SVi) with flow rate (FR) in the hemodynamic classification of severe aortic stenosis (AS) with preserved ejection fraction (EF), in order to evaluate its prognostic value. METHODS: A total of 529 patients (78.8 ± 9.8 years old, 44.1% males) with isolated severe AS (aortic valve area, AVA < 1 cm2), EF ≥50%, in sinus rhythm, who underwent transthoracic echocardiography, were stratified by FR (≥/< 200 mL/s) and mean pressure gradient (MG) (≥/< 40 mm Hg): FRnormal/MGhigh, FRlow/MGhigh, FRnormal/MGlow, and FRlow/MGlow. RESULTS: Aortic valve replacement was more frequently performed in the FRnormal/MGhigh than in the FRlow/MGlow group (69.3 vs. 47%, respectively, p < 0.0001), yielding a similar survival benefit across all four groups. Over a median follow-up of 51 ± 29 months, there were 249 deaths. In highly adjusted models, the FRlow/MGlow group had a higher all-cause mortality (HR = 1.7, 95% CI: 1.1-2.6, p = 0.02) than patients with FRnormal/MGhigh. FR had a stronger association with AVA than SVi (r = 0.51 vs. 0.41, respectively, p = 0.0002), and a similar predictive value for death (AUC = 0.57 and 0.58, respectively, p = 0.88). CONCLUSIONS: The FRlow/MGlow subset of AS is associated with the worst prognosis, and FR is not superior to SVi in the hemodynamic classification of severe AS.

Absence of left ventricular hypertrophy in severe isolated aortic stenosis and preserved left ventricular systolic function.

BACKGROUND AND AIM OF THE STUDY: Recent evidence challenges the paradigm that left ventricular hypertrophy (LVH) is required to preserve left ventricular systolic performance in severe aortic stenosis (AS). The study aims were to determine the clinical, echocardiographic and prognostic implications in a cohort of patients with symptomatic severe AS, a preserved left ventricular ejection fraction (LVEF), and an absence of LVH. METHODS: Echocardiographic, clinical, aortic valve replacement (AVR)-related and all-cause death data were analyzed in 512 patients (253 males, 259 females; mean age 78.4 +/- 10.3 years) with severe AS and a preserved LVEF. Of these patients, 21% were enrolled prospectively, and the mean follow up was 40.4 +/- 32.5 months. RESULTS: By using the American Society of Echocardiography equation for left ventricular mass calculation, LVH was shown to be present in 330 patients (63%) and absent from 182 (36%). Typically, patients without LVH had a larger body surface area, were more often male, had a larger aortic valve area index (AVAi), and had similar LVEFs and rates of AVR as compared to those with LVH. A total of 59 deaths (32.4%) occurred among patients without LVH, and 134 (40.6%) among those with LVH (p = 0.07). When the left ventricular mass index (LVMi) was analyzed as a continuous variable, in both unadjusted and adjusted models for demographics, clinical characteristics, medications, AVAi, LVEF, and systemic vascular resistance, no association was found between LVMi and survival (p = 0.26). However, only patients with a normal LVMi and relative wall thickness had a survival benefit when compared to those with any pattern of abnormal left ventricular geometry (p = 0.01). CONCLUSION: LVH was absent in more than one-third of patients with severe AS, and was not associated with worse outcomes. A normal left ventricular geometry was associated with lower mortality rates, while AVR was associated with prolonged survival, regardless of LVMi. Mechanisms other than compensatory hypertrophy appear capable of offsetting the adverse effects of afterload excess in AS.

Clinical and echocardiographic correlates of mortality in medically treated patients with severe isolated aortic stenosis and normal left ventricular ejection fraction.

BACKGROUND: Many symptomatic patients with severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF) are denied surgery and have a grim prognosis with medical management. METHODS AND RESULTS: Between 2003 and 2012, among 550 patients with severe isolated AS and preserved LVEF on transthoracic echocardiography, 241 did not undergo aortic valve replacement (mean age, 83.2±7.6 years; 54% female; aortic valve area index, 0.40±0.13cm(2)/m(2); mean LVEF, 64.8±7.6%) and 67% presented with cardiac symptoms. At a mean follow-up of 25.5±25.1 months, 134 patients (56%) had died. Survival at 1, 5 and 9.5 years was 71%, 28% at 12%, respectively. Median survival was 36.3 months (95% confidence interval [CI]: 27.2-42.4 months). In unadjusted analyses, age, heart failure, hypertension, renal insufficiency, left atrial size, pulmonary artery systolic pressure (PASP), relative wall thickness and LV mass/LV end diastolic volume ratio were associated with mortality. On multivariate analysis adjusted for all significant univariate predictors, age ≥78 years, history of hypertension, left atrial diameter ≥40mm and PASP ≥42mmHg gave a joint area under the curve of 0.80 (95% CI: 0.73-0.86) for mortality. CONCLUSIONS: In medically treated patients with severe isolated AS and preserved LVEF, older age, history of hypertension, and echo-Doppler variables reflecting LV diastolic dysfunction are independent predictors of death.

Severe isolated aortic stenosis with normal left ventricular systolic function and low transvalvular gradients: pathophysiologic and prognostic insights.

BACKGROUND AND AIM OF THE STUDY: A significant proportion of patients with severe valvular aortic stenosis (AS) and preserved left ventricular (LV) systolic function have low transvalvular gradients. The study aim was to determine the mechanisms and outcome of patients with this hemodynamic profile of AS. METHODS: Among 1,679 patients who underwent transthoracic echocardiography for the evaluation of AS at the authors' institution, 215 (105 females, 110 males; mean age: 77 +/- 10 years) had isolated AS (mean aortic valve area index 0.39 +/- 0.1 cm2/m2), normal sinus rhythm and normal LV ejection fraction. The mean follow up was 23 +/- 12 months, and the end-points were mortality, aortic valve replacement (AVR), or mortality or AVR. RESULTS: Forty-seven patients had a transvalvular mean gradient (MG) <30 mmHg (MG(low)) and 168 had MG > or = 30 mmHg (MG(high)). Compared to MG(high), the MG(low) group had a higher prevalence of hypertension, lower LV end-diastolic volume index (47 +/- 9 versus 56 +/- 12 ml/m2, p <0.0001), lower LV stroke vol-ume index (37 +/- 12 versus 41 +/- 11 ml/beat, p <0.0002), a lesser severity of stenosis (aortic valve area index 0.37 +/- 0.09 versus 0.46 +/- 0.09 cm2/m2, p <0.0001) and a higher systemic vascular resistance (2163 +/- 754 versus 1879 +/- 528 dyne cm s(-5). The LV end-diastolic volume index, systemic vascular resistance and energy loss index were predictors of MG <30 mmHg (OR = 0.30, 95% CI, 0.12, 0.62; OR = 3.05, 95% CI, 1.71, 6.26; and OR = 6.76, 95% CI, 3.44,15.38, respectively). MG <30 mmHg (MGhigh) was associated with almost 50% lower referral to surgery and a two-fold increase in preoperative mortality. CONCLUSION: In severe AS with a normal LV ejection fraction, MG <30 mmHg is related to a lesser severity of stenosis, a smaller LV volume, a lower flow rate and a higher systemic vascular resistance. Compared to the MG(high) group, these patients were less frequently referred to surgery and had a higher mortality.