Clinical Outcomes in High-Gradient, Classical Low-Flow, Low-Gradient, and Paradoxical Low-Flow, Low-Gradient Aortic Stenosis After Transcatheter Aortic Valve Implantation: A Report From the SwissTAVI Registry

Abstract

Background In view of the rising global burden of severe symptomatic aortic stenosis, its early recognition and treatment is key. Although patients with classical low-flow, low-gradient (C-LFLG) aortic stenosis have higher rates of death after transcatheter aortic valve implantation (TAVI) when compared with patients with high-gradient (HG) aortic stenosis, there is conflicting evidence on the death rate in patients with severe paradoxical low-flow, low-gradient (P-LFLG) aortic stenosis. Therefore, we aimed to compare outcomes in real-world patients with severe HG, C-LFLG, and P-LFLG aortic stenosis undergoing TAVI. Methods and Results Clinical outcomes up to 5 years were addressed in the 3 groups of patients enrolled in the prospective, national, multicenter SwissTAVI registry. A total of 8914 patients undergoing TAVI at 15 heart valve centers in Switzerland were analyzed for the purpose of this study. We observed a significant difference in time to death at 1 year after TAVI, with the lowest observed in HG (8.8%) aortic stenosis, followed by P-LFLG (11.5%; hazard ratio [HR], 1.35 [95% CI, 1.16-1.56]; P<0.001) and C-LFLG (19.8%; HR, 1.93 [95% CI, 1.64-2.26]; P<0.001) aortic stenosis. Cardiovascular death showed similar differences between the groups. At 5 years, the all-cause death rate was 44.4% in HG, 52.1% in P-LFLG (HR, 1.35 [95% CI, 1.23-1.48]; P<0.001), and 62.8% in C-LFLG aortic stenosis (HR, 1.7 [95% CI, 1.54-1.88]; P<0.001). Conclusions Up to 5 years after TAVI, patients with P-LFLG have higher death rates than patients with HG aortic stenosis but lower death rates than patients with C-LFLG aortic stenosis.

Keywords: SwissTAVI; low‐flow, low‐gradient; outcomes in aortic stenosis; transcatheter aortic valve implantation; valvular heart disease.

Figure 1. Flowchart of patient selection.

AS indicates aortic stenosis; AVA, aortic valve area; dp mean, mean aortic pressure gradient; LFLG, low‐flow, low‐gradient; LVEF, left ventricular ejection fraction; and TAVI, transcatheter aortic valve implantation.

Figure 2. All‐cause deaths.

Patients with high‐gradient aortic stenosis as reference (top), all‐cause death in patients with high gradient (blue), classical low‐flow, low‐gradient (orange), and paradoxical low‐flow, low‐gradient (red), aortic stenosis (middle), and all‐cause death at 30 d, 1 y, and 5 y adjusted for age, sex, and STS‐PROM (bottom). adj indicates adjusted; C‐LFLG, classical low‐flow, low‐gradient; HG, high‐gradient, HR, hazard ratio; LFLG, low‐flow, low‐gradient; P‐LFLG, paradoxical low‐flow, low‐gradient; and STS‐PROM, Society of Thoracic Surgeons Predicted Risk of Mortality.

Figure 3. Cardiovascular death in patients undergoing TAVI with high‐gradient (HG) (blue), classical low‐flow, low‐gradient (C‐LFLG) (orange) and paradoxical low‐flow, low‐gradient (P‐LFLG) (red) aortic stenosis.

Adjusted hazard ratio (HR), 2.11 (95% CI, 1.74–2.55; P<0.001); C‐LFLG vs HG (HR, 1.34 [95% CI, 1.12–1.62]; P=0.002); P‐LFLG vs HG (HR, 0.64 [95% CI, 0.52–0.79]; P<0.001) P‐LFLG vs C‐LFLG. C‐LFLG indicates classical low‐flow, low‐gradient; HG, high‐gradient; LFLG, low‐flow, low‐gradient; and P‐LFLG, paradoxical low‐flow, low‐gradient.