Abstract
Background
Outcomes for different subtypes of aortic stenosis defined by transvalvular flow and gradient after transcatheter aortic valve implantation (TAVI) are still subjects of debate.
Purpose
The aim of the study was to evaluate the prognostic impact of the initial transvalvular flow rate and aortic mean gradient on survival and to assess the changes of left ventricular function after TAVI.
Patients and Methods
From 2008. to 2017.06.30. TAVI was performed in 300 cases in our Institute (127 men, 173 women, mean age 80,0 ± 5,8 years) with severe (aortic valve area <1,0 cm²) symptomatic aortic stenosis (AS) and contraindication or high risk for surgery. Median time for follow-up was 28 (0-115) months, Echocardiography was performed before and 12 months after TAVI. Patients were divided into four groups according to flow (F) , aortic mean gradient (Gr) and ejection fraction (EF):
HG
Gr ≥ 40 mmHg (n = 237)
LF-LG : F ≤ 35 ml/m2, Gr < 40 mmHg and EF < 50% (n = 41)
PLF-LG: F ≤ 35 ml/m2, Gr < 40 mmHg and EF ≥50% (n = 9)
NF-LG: F > 35 ml/m2 and Gr < 40 mmHg (n = 13)
Our primary objective was the analysis of 30-day, 1-year and 3-year all-cause mortality of these groups, secondary goal was to observe the changes in EF after 12 months in the survivors.
Results
In the whole patient group 30-day all-cause mortality was 4,3%, 1-year 17,0% and 3-year 62,0%. The NFLG group had the most favourable outcomes (mortality: 30d 0, 1-year: 7,7%, 3-year: 46,2%). Mortality was low in the HG group in the 1st year (30-day: 3,8%, 1-y: 14,3%), but it increased to 62,8% at 3-year. Mortality rates were intermediate in the PLF-LG group (30-day 0, 1-year 22,2%, 3-year 55,6%) and were the highest in LF-LG (30-day 12,2%, p = 0,03 vs HG, 1-year 34,2% p = 0,005 vs. HG, 3-year 75,6%).
Among clinical and echocardiographic variables only moderate or severe paravalvular aortic regurgitation (p = 0,03) and severe renal dysfunction (GFR <30 ml/min, p = 0,02) were independent predictors of all-cause 1-year mortality.
In patients with severe (EF < 30%) , moderate (EF 30-40%) or mild ( EF 41-50%) systolic dysfunction the EF improved after TAVI (23,5 ± 3,5% vs. 30,3 ± 7,9% p < 0,001, 33,6 ±3,6% vs. 43,0 ± 10,5% p = 0,003, 45,5 ± 3,1% vs. 54,3 ± 8,7% p < 0,001) regardless of the initial flow and gradient subtype of AS.
Conclusions
Low flow-low gradient aortic stenosis is associated with worse short or long term prognosis after TAVI, therefore this subtype of AS needs detailed risk stratification before-, and careful management after TAVI. Improvement of initial left ventricular dysfuncion can be expected after TAVI.
Prognostic impact of echocardiographic mean transvalvular gradients in patients with aortic stenosis and low flow undergoing transcatheter aortic valve implantation