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TAVR in Low-Flow Low-Gradient Aortic Stenosis
Study Questions:
What are the outcomes (including change in left ventricular ejection fraction [LVEF]) following transcatheter aortic valve replacement (TAVR) among patients with low-flow low-gradient (LFLG) aortic stenosis (AS) and reduced LVEF?
Methods:
The TOPAS-TAVI multicenter registry included 287 patients with LFLG AS and reduced LVEF (mean gradient <35 mm Hg, valve area <1.0 cm2, LVEF ≤40%) undergoing TAVR. Dobutamine stress echocardiography (DSE) was performed before TAVR in 234 patients, and the presence of contractile reserve was defined as a ≥20% increase in LV stroke volume. Transthoracic echocardiography was repeated at hospital discharge and at 1-year follow-up. Clinical follow-up was obtained at 1 and 12 months, and yearly thereafter.
Results:
The median Society of Thoracic Surgeons risk score of the study population was 7.7% (interquartile range 5.3-12.0%), and the mean LVEF and transvalvular gradient were 30 ± 10 and 25 ± 7 mm Hg, respectively. The presence of LV contractile reserve during DSE was observed in 45% of patients. Mortality rates were 3.8%, 20.1%, and 32.3% at 30 days, 1 year and 2 years, respectively. On multivariable analysis, chronic obstructive pulmonary disease (p = 0.02) and lower hemoglobin values (p < 0.001) were associated with increased all-cause mortality. Lower hemoglobin values (p = 0.004) and moderate-to-severe aortic regurgitation post-TAVR (p = 0.02) were predictors of a composite endpoint of all-cause mortality and re-hospitalization due to heart failure. LVEF increased by 8.3% (95% confidence interval, 6-11%) at 1-year follow-up, and the lack of prior coronary artery bypass grafting (p = 0.004), a lower LVEF at baseline (p < 0.001), and a lower stroke volume index at baseline (p = 0.019) were associated with greater increase in LVEF. The absence of contractile reserve on baseline DSE was not associated with any negative effect on clinical outcomes or LVEF changes at follow-up.
Conclusions:
TAVR was associated with good periprocedural outcomes among patients with LFLG AS and reduced LVEF. However, approximately one third of patients with LFLG AS who underwent TAVR had died by 2-year follow-up; with pulmonary disease, anemia, and residual paravalvular leak associated with worse outcomes. LVEF improved following TAVR, but DSE did not predict clinical outcomes or LVEF changes over time.
Perspective:
DSE is useful among patients with LFLG severe AS and reduced LVEF to distinguish true-severe from pseudo-severe AS. 2017 Appropriate Use Criteria for AS (J Am Coll Cardiol 2017;70:2566-98) suggest that TAVR or surgical AVR (SAVR) is appropriate for patients with LFLG severe AS and LVEF 20-49% regardless of LV contractile reserve on DSE, but appropriate among patients with LVEF <20% only if there is evidence of LV contractile reserve on DSE. The absence of LV contractile reserve on DSE previously has been associated with poor prognosis after SAVR (Monin JL, et al. Circulation 2003;108:319-24). Data from this multicenter registry suggest that the absence of LV contractile reserve is not an independent predictor of either clinical outcomes or LVEF after TAVR, and support an expanding role for TAVR among patients with LFLG severe AS and reduced LVEF.
Keywords: Anemia, Aortic Valve Stenosis, Aortic Valve Insufficiency, Cardiac Surgical Procedures, Coronary Artery Bypass, Diagnostic Imaging, Echocardiography, Echocardiography, Stress, Heart Failure, Heart Valve Diseases, Hemoglobins, Lung Diseases, Pulmonary Disease, Chronic Obstructive, Stroke Volume, Transcatheter Aortic Valve Replacement, Ventricular Function, Left
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