OBJECTIVES: We reported that patients with small aortic valve area (AVA) and low flow despite preserved left ventricular ejection fraction (LVEF), i.e. â€˜paradoxicalâ€™ low flow (PLF), have worse outcomes compared with patients with normal flow (NF), although they generally have a lower mean gradient (MG). The aortic valve weight (AVW) excised at the time of valve replacement is a flow-independent marker of stenosis severity. The objective of this study was to compare the AVW of patients with PLF and MG<40 mmHg with the AVW of patients with NF and MGâ‰¥40 mmHg.
METHODS: We recruited 250 consecutive patients undergoing valve replacement (Cohort A) for severe stenosis. Among them, 33 (13%) were in PLF [LVEF > 50% but stroke volume index (SVi) â‰¤ 35 mL/m2] with MG < 40 mmHg (PLF-LG group) and 105 (42%) were in NF (LVEF > 50% and SVi > 35 mL/m2) with MG â‰¥ 40 mmHg (NF-HG group).
RESULTS: Despite a much lower MG (29 Â± 7 vs. 53 Â± 10 mmHg; P < 0.0001), patients in the PLF-LG group had a similar AVA (0.73 Â± 0.12 vs. 0.69 Â± 0.13; P = 0.19) compared with those in the NF-HG group.The AVW [median (interquartile): 1.90 (1.63â€“2.50) vs. 2.60 (1.66â€“3.32)] and prevalence of bicuspid phenotype (15 vs. 42%) were lower in the PLF-LG group than in the NF-HG group. However, AVWs analyzed separately in the tricuspid and bicuspid valves were similar in both groups [tricuspid valves: 1.80 (1.63â€“2.50) vs. 2.30 (1.58â€“3.00) g; P = 0.26 and bicuspid valves: 2.72 (1.73â€“3.61) vs. 2.60 (2.10â€“3.55) g; P = 0.93]. When using cut-point values of AVW established in another series of non-consecutive patients (n = 150, Cohort B) with NF and concordant Doppler-echocardiographic findings, we found that the percentage of patients with evidence of severe stenosis in Cohort A was 70% in patients with PLF-LG and 86% in patients with NF-HG.
CONCLUSIONS: The aortic valve weight data reported in this study provide evidence that a large proportion of patients with PLF and low-gradient have a severe stenosis and that the gradient may substantially underestimate stenosis severity in these patients. A multi-parametric approach including all Doppler-echocardiographic parameters of valve function as well as other complementary diagnostic tests may help correctly identify these patients.