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Low-Flow, Low-Gradient AS With Reduced LVEF (TOPAS-TAVI)
Study Questions:
What are the effects on clinical outcomes and left ventricular ejection fraction (LVEF) after transcatheter aortic valve replacement (TAVR) among patients with low-flow, low-gradient (LFLG) aortic stenosis (AS) and severe LV systolic dysfunction?
Methods:
This multicenter registry is a substudy of the TOPAS (True or Pseudo-Severe Aortic Stenosis)–TAVI registry that included patients with classic LFLG AS, defined as a mean transvalvular gradient <35 mm Hg, an effective orifice area <1.0 cm2, and LVEF ≤40%. Patients were divided in groups with very low (<30%) LVEF and low (30-40%) LVEF. Dobutamine stress echocardiography (DSE) was performed before TAVR in a subset with very low LVEF; the presence of contractile reserve was defined as a ≥20% increase in stroke volume. Clinical outcomes were assessed at 1 and 12 months, and yearly thereafter; and echocardiography was performed at 1-year follow-up. Retrospective data were collected from 2007 to 2013 and prospective data from January 2013 to March 2018. The main outcomes were change over time in LVEF, and periprocedural and late mortality.
Results:
A total of 293 patients were included, including 128 (44%) with very low LVEF and 165 (56%) with low LVEF. The mean age was 80 ± 7 years, and most (214 [73%]) were men. The mean LVEF in the very low LVEF group was 22 ± 5%, compared with 37 ± 7% in the low LVEF group (p < 0.001). There were no significant differences between groups in the rates of periprocedural mortality (very low LVEF, 6 of 128 participants [4.7%]; low LVEF, 6 of 165 participants [3.6%]; p = 0.65) and late (median [interquartile range] 23 [6-38] months) mortality (very low LVEF, 57 [44.5%]); low LVEF, 75 [45.5%]; hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.61-1.53; p = 0.88). Patients with very low LVEF had a greater increase in LVEF at the 1-year follow-up examination (mean absolute increase 11.9%; 95% CI, 8.8%-15.1%) than did the low LVEF group (3.6%; 95% CI, 1.1%-6.1%; p < 0.001). Among 92 patients with very low LVEF who underwent preprocedural DSE, there was a lack of contractile reserve in 45 (49%), but this had no relation to clinical outcomes or change over time in LVEF.
Conclusions:
Patients with LFLG AS and severe LV systolic dysfunction who underwent TAVR had similar clinical outcomes compared to counterparts with milder LV dysfunction. The TAVR procedure was associated with a significant increase in LVEF regardless of contractile reserve. The authors concluded that these results support TAVR among patients with LFLG AS and reduced LVEF, regardless of the severity of LV dysfunction and DSE results.
Perspective:
DSE is an important tool to help distinguish severe from pseudosevere AS among patients with LFLG AS and reduced LVEF. Among patients undergoing surgical AVR, the absence of LV contractile reserve on preprocedural DSE portends high perioperative risk. However, these data suggest that patients with LFLG AS and LVEF <30% who undergo TAVR have similar periprocedural and ~2-year mortality compared to patients with LVEF 30-40%. Patient selection presumably plays an important role. In addition, the ~2-year mortality of 45% underscores the poor prognosis of the whole group of patients with severe AS and LV systolic dysfunction who undergo TAVR.
Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Diagnostic Imaging, Echocardiography, Echocardiography, Stress, Heart Valve Diseases, Heart Valve Prosthesis, Geriatrics, Outcome Assessment, Health Care, Stroke Volume, Systole, Transcatheter Aortic Valve Replacement, Ventricular Dysfunction, Left
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