Low Gradient, Normal Flow Aortic Stenosis: Changes in Quality of Life with TAVR

There is no question as regards the recommended treatment for symptomatic severe aortic stenosis, seeing as both transcatheter and surgical aortic valve replacement (TAVR and SAVR) have shown to significantly improve prognosis. This is despite the fact that there is still certain ambiguity around its characterization, which looks to define it according to hemodynamic severity patterns. These profiles have been classified as high gradient (HG AS), low gradient (LG AS) and low flow aortic stenosis (LF AS) with reduced ejection fraction (FEY, paradoxical subtype).

Estenosis aórtica bajo gradiente y flujo normal: Cambios en la calidad de vida con TAVI

Among patients with preserved FEY, a subtype of considerable 15% will present low and normal flow, defined as systolic volume index (SVi) ≥35mm per m2. There is still no consensus as to the adequate timing to treat this subtype. The current available evidence in this regard is contradicting, with observational studies that favor medical treatment over intervention, observing an unfavorable prognosis, as registries have shown higher mortality in this group, vs moderate AS. 

Given the limitations to the correct observation of the aortic valve area (AVA), there is certain disagreement when it comes to determining severity thresholds. Even though NF LG patients present reduced gradients, AS severity might be underestimated.  This is because, on average, 1.0 cm2 AVA determined by ECG, is associated to 28 mmHg mean gradient, instead of 40 mmHg, in NF conditions. 

NF LG patients are a heterogeneous group, and there is consensus to include them in trials. However, the current guidelines do not contemplate these patients. The aim of this study was to compare changes in quality of life (QoL) and clinical improvement in NF-LG patients treated with TAVR.

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It included consecutive patients undergoing TAVR for severe AS over a period of 8 years at Michigan University, excluding patients with moderate-severe AS. Patients were stratified into 4 hemodynamic profiles: 1) classic, with high gradient (HG AS ≥4.0 m/s peak velocity or ≥40 mmHg MG), 2) classic LF-LG (<4.0 m/s PV and <40 mmHg MG, with <1 AVA  and <50% Fey), 3) paradoxic LF-LG (<4.0 m/s PV and <40 mmHg MG, with <1 AVA and ≥50% Fey and <35 mL/m2  SVi) and NF-LG (<4.0 m/s PV and <40 mmHg MG, with <1 AVA, ≥50% Fey and ≥35 mL/m2SVi). They assessed a composite of clinical improvement, consisting of survival at one year, and clinically improved QoL according to KCCQ score.

A total 860 patients were included in the analysis: 42.8% presented HG AS and 28.5% presented NF-LG. The latter were older, and presented higher prevalence of myocardial infarction. Most patients received a self-expanding valve at TAVR (86.6%) and similar rates of pacemaker implantation and sever aortic failure were observed post procedure. NF LG patients presented lower mean aortic gradient at 30 days, vs. the classic HG AS patients (7.8 vs. 9.9 mmHg, respectively, P < 0.001).

As regards total mortality, 10% of patients died within a year. Morality rate at one year was higher for patients with NF-LG (11.8%) vs HG (6.2%, p = 0.001). There was a significant trend towards early mortality within one year followup (log-rank P = 0.003).

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As regards quality of life, all four groups presented significant improvement with TAVR vs baseline status. Both the AS HG group and NF LG patients showed similar increase (21.4 vs. 20.8, respectively, P = 0.44). Clinical improvement was reached in 63.9% of patients with NF, vs. 70.4% of patients with HG. At primary adjustment, the rate of primary end points resulted significantly different, which shows a tendency towards worse QoL outcomes for NF patients. 


In this single center study, assessing QoL after TAVR in patients with NF, we observed similar clinical improvement compared against other hemodynamic profiles. However, we should note there is early mortality in patients with normal flow, which calls for further research and better detection of this subtype.

Dr. Andrés Rodríguez

Dr. Andrés Rodríguez.
Member of the Editorial Board of SOLACI.org.

Original Title: Quality of Life After Transcatheter Aortic Valve Replacement in Normal-Flow, Low-Gradient Aortic Stenosis.

Reference: Khaleel, I, Harris, A, Seth, M. et al. Quality of Life After Transcatheter Aortic Valve Replacement in Normal-Flow, Low-Gradient Aortic Stenosis. JACC Adv. 2023 Nov, 2 (9). https://doi.org/10.1016/j.jacadv.2023.100641.

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