Development of paradoxical low-flow, low-gradient severe aortic stenosis

Objective Among patients with severe aortic stenosis (sAS) and preserved LVEF, those with low-flow, low-gradient sAS (LFLG-sAS) have an adverse prognosis. It has been proposed that LFLG-sAS represents an end-stage point of sAS, but longitudinal information has not been described. The aim was to determine whether LFLG-sAS represents an end-stage consequence of normal-flow, high-gradient sAS (NFHG-sAS) or a different entity. Methods From our transthoracic echocardiogram (TTE) database, we identified patients with sAS (aortic valve area <1 cm2) and preserved LVEF (≥50%), and from these, patients with LFLG-sAS (stroke volume index <35 mL/m2 and mean transvalvular gradient <40 mm Hg) who had ≥1 additional TTE within five years prior to the index TTE. Patients were age/sex/date matched 2:1 with patients with NFHG-sAS and normal-flow, low-gradient (NFLG)-sAS who also had ≥1 TTE. Included were 1203 TTEs (383 index studies and 820 preceding studies). Results In 78 patients with LFLG-sAS, an HG stage preceded the index TTE in only 4 (5%). During the five years preceding the index TTE, patients with LFLG-sAS developed increasing relative wall thickness (0.42 to 0.49; p<0.001) without change in LV mass index. Patients with NFHG-sAS had a marked increase in LV mass index (87 to 115 g/m2; p<0.001). Patients with LFLG-sAS demonstrated the greatest reduction in LV end-diastolic diameters (−3 vs −1 for NFLG-sAS vs +2 mm for NFHG-sAS; p=0.001), deceleration time (−55 vs −3 vs +3 ms, respectively; p<0.01) and LVEF (−4 vs 0 vs 0%, respectively; p=0.01). Conclusions LFLG-sAS is a distinct presentation of sAS preceded by a unique remodelling pathway and is uncommonly preceded by an HG stage.