Predictors of Mortality and Outcomes of Therapy in Low-Flow Severe Aortic Stenosis

Abstract

Background-The prognosis and treatment of patients with low-flow (LF) severe aortic stenosis are controversial. Methods and Results-The Placement of Aortic Transcatheter Valves (PARTNER) trial randomized patients with severe aortic stenosis to medical management versus transcatheter aortic valve replacement (TAVR; inoperable cohort) and surgical aortic valve replacement versus TAVR (high-risk cohort). Among 971 patients with evaluable echocardiograms (92%), LF (stroke volume index ≤35 mL/m 2 ) was observed in 530 (55%); LF and low ejection fraction (<50%) in 225 (23%); and LF, low ejection fraction, and low mean gradient (<40 mm Hg) in 147 (15%). Two-year mortality was significantly higher in patients with LF compared with those with normal stroke volume index (47% versus 34%; hazard ratio, 1.5; 95% confidence interval, 1.25-1.89; P=0.006). In the inoperable cohort, patients with LF had higher mortality than those with normal flow, but both groups improved with TAVR (46% versus 76% with LF and 38% versus 53% with normal flow; P<0.001). In the high-risk cohort, there was no difference between TAVR and surgical aortic valve replacement. In patients with paradoxical LF and low gradient (preserved ejection fraction), TAVR reduced 1-year mortality from 66% to 35% (hazard ratio, 0.38; P=0.02). LF was an independent predictor of mortality in all patient cohorts (hazard ratio, ≈1.5), whereas ejection fraction and gradient were not. Conclusions-LF

Predictors of Mortality and Symptomatic Outcome of Patients With Low‐Flow Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement

“…Our findings confirm the high prevalence of pLF‐LG and similar worse prognosis of those patients compared with cLF‐LG, which is in line with those studies integrating SVI as an essential parameter for group definition 1, 19, 22, 23. These data support the above mentioned thesis that flow, rather than the mechanism for reduced flow, is the key prognostic factor1 and that an LF state might be a sign for an advanced disease. The divergence compared with the analysis derived from the German Aortic Valve Registry9 might be caused by the definition of pLF‐LG, including only LV‐EF ≥50% and MPG <40 mm Hg but not SVI, which may have led to the inclusion of nonsevere AS in this group.…”

“…Studies show comparable outcomes to NF‐HG,9 a higher mortality in pLF‐LG compared with NF‐HG but lower compared with cLF‐LG,23 and those with equal mortality rates in pLF‐LG and cLF‐LG but higher compared with NF‐HG 19. Our findings confirm the high prevalence of pLF‐LG and similar worse prognosis of those patients compared with cLF‐LG, which is in line with those studies integrating SVI as an essential parameter for group definition 1, 19, 22, 23. These data support the above mentioned thesis that flow, rather than the mechanism for reduced flow, is the key prognostic factor1 and that an LF state might be a sign for an advanced disease.…”

“…Our study confirms and expands the knowledge about the impact of LF on the outcome of patients undergoing TAVR by corroborating the findings of these smaller studies and proves the independence of SVI as a predictor of mortality. In our study, periprocedural complications were included in the Cox regression models but were not reported1, 19 or not included in the multivariable analyses in the aforementioned studies,23 despite the fact that periprocedural complications are known to affect long‐term mortality 21. The higher rate of bleeding and access site complications in NF‐HG and pLF‐LG could also be attributed to the higher amount of women in these groups who are known to experience these complications more frequently,32 but sex was included in our Cox regression model to adjust for this potential confounder.…”

“…The divergence compared with the analysis derived from the German Aortic Valve Registry9 might be caused by the definition of pLF‐LG, including only LV‐EF ≥50% and MPG <40 mm Hg but not SVI, which may have led to the inclusion of nonsevere AS in this group. Despite the higher mortality in pLF‐LG and cLF‐LG after TAVR, those patients derive a mortality benefit from valve replacement compared with medical therapy, which seems to be comparable between TAVR and surgical aortic valve replacement 1, 17…”

“…LF states are associated with either poor prognosis, if treated medically,16 or with increased operative mortality, if treated by surgical aortic valve replacement16, 17, 18 or TAVR 19. Data in TAVR cohorts are characterized by different definitions of AS entities and missing information on SVI, leading to an inconclusive assessment on the impact of LV‐EF, mean pressure gradient (MPG), and SVI on outcome 1, 9, 10, 19, 20, 21, 22, 23. Beyond survival, it is also recognized that some patients fail to experience a benefit in functional capacity or morbidity after TAVR 24.…”