Goal
To characterise the mechanics chargeable for the decreased ejection fraction (rEF) in high-gradient extreme aortic stenosis (AS).
Strategies
21 sufferers with high-gradient extreme AS (aortic valve space (AVA) <1.0 cm2 and imply gradient (MG) >40 mm Hg) had been included. They included 9 sufferers with rEF (EF <50%) and 12 with preserved ejection fraction (pEF) (EF >50%). Valve space and MG had been assessed echocardiographically, and myocardial fibrosis was quantified utilizing MRI. Load-independent measures of intrinsic contractility was assessed with pressure-volume haemodynamics.
Outcomes
80% of the cohort was feminine, with a imply age of 64 years. Sufferers had been matched for age, intercourse and physique floor space. Load-independent contractile operate was comparable between the rEF and pEF teams: preload recruitable stroke work slope (101 vs 112 mm Hg; p=0.65), end-systolic pressure-volume relationship slope (1.91 vs 1.28 mmHg/mL; p=0.07) and Starling Contractile Index slope (3.47 vs 7.96 mm Hg/mL/s; p=0.31). Finish-systolic wall stress and valvuloarterial impedance had been greater in instances with rEF (150 vs 83.5 N/cm2; p<0.01 and 4.8 vs 3.4 mm Hg/mL; p=0.05), pushed by greater levels of valvular stenosis (valve space 0.46 vs 0.78 cm2; p<0.01). The rEF group was extra symptomatic (New York Coronary heart Affiliation 3.3 vs 2.3; p=0.02), with greater pulmonary pressures (50 vs 30 mm Hg; p=0.04) and extra fibrosis (24% vs 13% of left ventricular mass; p=0.03).
Conclusion
The pathophysiological drawback in sufferers with high-gradient AS with rEF pertains to an excessively elevated afterload as a consequence of extra extreme valvular stenosis, with preserved intrinsic contractile operate. Myocardial fibrosis within the rEF group didn’t translate into worse muscle operate.