Clinical outcome and functional characteristics of patients with asymptomatic low-flow low-gradient severe aortic stenosis with preserved ejection fraction are closer to high-gradient severe than to moderate aortic stenosis

Prognostic Relevance of Gradient and Flow Status in Severe Aortic Stenosis

Background: Severe aortic stenosis (AS) may present with different flow, gradient and left ventricular ejection fraction (LVEF) patterns. Paradoxical low-flow low-gradient (PLF-LG) severe AS has a specific clinical profile, but its prognosis and management remain controversial. Our aim is to evaluate the impact of different AS patterns in the incidence of major clinical events. Methods: A retrospective observational study was carried out on all the consecutive patients diagnosed with severe AS at our tertiary hospital centre in 2021. Echocardiographic measurements were carefully reviewed, and patients were classified following current guidelines into four categories: high gradient (HG), concordant low-flow low-gradient (CLF-LG), paradoxical low-flow low-gradient (PLF-LG) and normal-flow low-gradient (NF-LG). The baseline characteristics and clinical events (heart failure admission, intervention and death) at 1-year follow-up were collected from medical records. The association between categories and events was established using Student's t test or ANOVA as required. Results: 205 patients with severe AS were included in the study (81 ± 10 years old, 52.7% female). Category distribution was as follows: HG (138, 67.3%), PLF-LG (34, 19.8%), CLF-LG (21, 10.2%) and NF-LG (12, 5.9%). During the follow-up, 24.8% were admitted due to heart failure, 68.3% received valve replacement (51.7% TAVR) and 22% died. Severe tricuspid regurgitation was more frequent in patients with PLF-LG than in HG AS (14.7% vs. 2.2%; p < 0.01). Despite no differences in intervention rate, more patients with PLF-LG (32.4% vs. 15.9%; p = 0.049) died during the evolution. Conclusions: The PLF-LG pattern was the second most common pattern of severe AS in our cohort, and it was related to a higher mortality with no differences in intervention rate. Thus, this controversial category, rather than being underestimated, should be followed closely and considered for early intervention.

Low-Flow, Low-Gradient Severe Aortic Stenosis in patients with preserved or reduced ejection fraction: a systematic literature review

OBJECTIVES

A systematic review of the literature was conducted to analyze the current evidence on low-flow, low-gradient severe aortic stenosis. This analysis aimed to differentiate between subgroups of patients with reduced and preserved left ventricular ejection fraction (LVEF).

METHODS

After conducting a systematic literature review, 35 observational studies were included. Out of these, 28 were prospective and 7 retrospective. The studies that included a mortality risk stratification of low-flow, low-gradient aortic stenosis (LF- LG AS) with both preserved and reduced LVEF were reviewed.

RESULTS

The importance of considering multiple clinical and echocardiographic variables in diagnostic evaluation and therapeutic decision-making was highlighted.

CONCLUSIONS

LF- LG AS, in any of its subgroups, is a common and challenging valve lesion. A careful assessment of severity and, in specific scenarios, a thorough reclassification is important. More high-quality studies are required to more precisely define the classification and prognosis of this entity.

Natural history of moderate aortic stenosis and predictors for mortality: Systematic review and Meta-analysis

Although the current guidelines advocate imaging surveillance for moderate aortic stenosis (AS), recent studies suggest a worse prognosis associated with moderate AS than previously reported. Considering the recent paradigm shift in AS management, the risk/benefit profile of aortic valve replacement (AVR) for moderate AS needs to be re-evaluated. Herein, we conducted meta-analyses of natural history and risk predictors in patients with moderate AS. PubMed and EMBASE were searched through May 2022 to identify studies that investigated the natural history of patients with moderate AS. Meta-analyses with random effects model were conducted. Our analysis included 20 observational studies which enrolled a total of 11,114 patients with moderate AS. The rate of all-cause death was 11.0 [95 % confidence interval (CI), 7.6-14.4] per 100 patients per year. Surgical or transcatheter AVR occurred at a rate of 8.5 (95 % CI, 6.2-10.8; I², 98.9 %) per 100 patients per year. Occurrence of AVR during follow-up [hazard ratio (HR) (95 % CI) =0.56 (0.42-0.75), p < 0.001] and early AVR for moderate AS [HR (95 % CI) = 0.47 (0.25-0.90), p = 0.02] were associated with significantly lower all-cause mortality, while left ventricular ejection fraction <50 % [HR (95 % CI) =1.84 (1.33-2.57), p = 0.0003] and symptomatic status [HR (95 % CI) = 1.52 (1.32-1.75), p < 0.0001] were associated with increased all-cause mortality. Sex difference was not related to all-cause mortality. Our meta-analysis suggested that moderate AS was associated with high mortality, especially in low left ventricular systolic function or symptomatic patients. In addition, significant portion of the patients underwent AVR during follow-up.

Impact of Moderate Aortic Stenosis on Long-Term Clinical Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

The clinical course of patients with moderate aortic stenosis (AS) remains incompletely defined.

OBJECTIVES

This study sought to analyze the clinical course of moderate AS and compare it with other stages of the disease.

METHODS

Multiple electronic databases were searched to identify studies on adult moderate AS. Random-effects models were used to derive pooled estimates. The primary endpoint was all-cause death. The secondary endpoints were cardiac death, heart failure, sudden death, and aortic valve replacement.

RESULTS

Among a total of 25 studies (12,143 moderate AS patients, 3.7 years of follow-up), pooled rates per 100 person-years were 9.0 (95% CI: 6.9 to 11.7) for all-cause death, 4.9 (95% CI: 3.1 to 7.5) for cardiac death, 3.9 (95% CI: 1.9 to 8.2) for heart failure, 1.1 (95% CI: 0.8 to 1.5) for sudden death, and 7.2 (95% CI: 4.3 to 12.2) for aortic valve replacement. Meta-regression analyses detected that diabetes (P = 0.019), coronary artery disease (P = 0.017), presence of symptoms (P < 0.001), and left ventricle (LV) dysfunction (P = 0.009) were associated with a significant impact on the overall estimate of all-cause death. All-cause mortality was higher in patients with reduced LV ejection fraction (<50%) than with normal LV ejection fraction: 16.5 (95% CI: 5.2 to 52.3) and 4.2 (95% CI: 1.4 to 12.8) per 100 person-years, respectively. Compared with moderate AS, the incidence rate difference of all-cause mortality was -3.9 (95% CI: -6.7 to -1.1) for no or mild AS and +2.2 (95% CI: +0.8 to +3.5) for severe AS patients.

CONCLUSIONS

Moderate AS appears to be associated with a mortality risk higher than no or mild AS but lower than severe AS, which increases in specific population subsets. The impact of early intervention in moderate AS patients having high-risk features deserves further investigation.

Prognosis of Paradoxical Low-Flow Low-Gradient Aortic Stenosis: A Severe, Non-critical Form, With Surgical Treatment Benefits

Objectives

To determine the risk of mortality and need for aortic valve replacement (AVR) in patients with low-flow low-gradient (LFLG) aortic stenosis (AS).

Methods

A longitudinal multicentre study including consecutive patients with severe AS (aortic valve area [AVA] < 1.0 cm²) and normal left ventricular ejection fraction (LVEF). Patients were classified as: high-gradient (HG, mean gradient ≥ 40 mmHg), normal-flow low-gradient (NFLG, mean gradient < 40 mmHg, indexed systolic volume (SVi) > 35 ml/m²) and LFLG (mean gradient < 40 mmHg, SVi ≤ 35 ml/m²).

Results

Of 1,391 patients, 147 (10.5%) had LFLG, 752 (54.1%) HG, and 492 (35.4%) NFLG. Echocardiographic parameters of the LFLG group showed similar AVA to the HG group but with less severity in the dimensionless index, calcification, and hypertrophy. The HG group required AVR earlier than NFLG (p < 0.001) and LFLG (p < 0.001), with no differences between LFLG and NFLG groups (p = 0.358). Overall mortality was 27.7% (CI 95% 25.3–30.1) with no differences among groups (p = 0.319). The impact of AVR in terms of overall mortality reduction was observed the most in patients with HG (hazard ratio [HR]: 0.17; 95% CI: 0.12–0.23; p < 0.001), followed by patients with LFLG (HR: 0.25; 95% CI: 0.13–0.49; p < 0.001), and finally patients with NFLG (HR: 0.29; 95% CI: 0.20–0.44; p < 0.001), with a risk reduction of 84, 75, and 71%, respectively.

Conclusions

Paradoxical LFLG AS affects 10.5% of severe AS, and has a lower need for AVR than the HG group and similar to the NFLG group, with no differences in mortality. AVR had a lower impact on LFLG AS compared with HG AS. Therefore, the findings of the present study showed LFLG AS to have an intermediate clinical risk profile between the HG and NFHG groups.

First-phase ejection fraction: association with remodelling and outcome in aortic valve stenosis

Background

First-phase ejection fraction (EF1), the left ventricular (LV) ejection fraction (EF) until the time of peak transaortic velocity, is a novel marker of subclinical LV dysfunction able to predict adverse events in aortic stenosis (AS). This study investigated the association between end-systolic wall stress (ESWS) and EF1 in severe AS, as well as the prognostic value of EF1 in severe asymptomatic AS.

Methods

Two prospectively gathered cohorts of 94 asymptomatic patients and 108 symptomatic patients scheduled for aortic valve replacement (AVR), all with severe AS (aortic valve area <1 cm²) were stratified according to the median value of EF1 (33%). EF1 was defined as the EF at peak transaortic velocity. Asymptomatic patients were followed up for 3 years for the combined end-point of death, AVR or admission with heart failure.

Results

EF1 correlated with EF and was inversely associated with ESWS. In multivariate regression analysis, ESWS (p<0.001) and replacement fibrosis measured by MRI (p=0.02) were associated with EF1. Among asymptomatic patients, EF1 above the median was associated with the combined primary endpoint (HR=0.53 (95% CI 0.33 to 0.87)), while global longitudinal strain and EF were not. Among 42 patients with discordant AS (mean gradient <40 mm Hg), EF1 above median was associated with the primary endpoint (HR 0.28 (95% CI 0.12 to 0.61)).

Conclusion

EF1 is an afterload-dependent measure that is associated with events in patients with asymptomatic severe AS. The afterload dependency of EF1 may be useful in timing of risk stratification in patients with discordant AS.

Trial registration numbers

NCT02395107 and NCT02316587.