No abstract

Exercise intolerance is a hallmark feature in heart failure with preserved ejection fraction (HFpEF). Prior heavy exercise (“priming exercise”) speeds pulmonary oxygen uptake (V̇o2p) kinetics in older adults through increased muscle oxygen delivery and/or alterations in mitochondrial metabolic activity. We tested the hypothesis that priming exercise would speed V̇o2p on-kinetics in patients with HFpEF because of acute improvements in muscle oxygen delivery. Seven patients with HFpEF performed three bouts of two exercise transitions: MOD1, rest to 4-min moderate-intensity cycling and MOD2, MOD1 preceded by heavy-intensity cycling. V̇o2p, heart rate (HR), total peripheral resistance (TPR), and vastus lateralis tissue oxygenation index (TOI; near-infrared spectroscopy) were measured, interpolated, time-aligned, and averaged. V̇o2p and HR were monoexponentially curve-fitted. TPR and TOI levels were analyzed as repeated measures between pretransition baseline, minimum value, and steady state. Significance was P < 0.05. Time constant (τ; tau) V̇o2p (MOD1 49 ± 16 s) was significantly faster after priming (41 ± 14 s; P = 0.002), and the effective HR τ was slower following priming (41 ± 27 vs. 51 ± 32 s; P = 0.025). TPR in both conditions decreased from baseline to minimum TPR ( P < 0.001), increased from minimum to steady state ( P = 0.041) but remained below baseline throughout ( P = 0.001). Priming increased baseline ( P = 0.003) and minimum TOI ( P = 0.002) and decreased the TOI muscle deoxygenation overshoot ( P = 0.041). Priming may speed the slow V̇o2p on-kinetics in HFpEF and increase muscle oxygen delivery (TOI) at the onset of and throughout exercise. Microvascular muscle oxygen delivery may limit exercise tolerance in HFpEF.

No abstract

Aortic stenosis is the most common valvular disease of the heart and is increasing in prevalence. Previous literature has found inferior outcomes for females undergoing surgical aortic valve replacement, while recent investigations have found equivalent or superior outcomes for females undergoing transcatheter aortic valve replacement (TAVR). PubMed and Medline were systematically searched for articles published from January 1, 2010, to April 30, 2021, for retrospective and prospective studies comparing outcomes between males and females undergoing TAVR. One thousand one hundred eighty titles and abstracts were screened, and 28 were included in this review. Risk of bias was assessed using questions derived from the ROBINS-I tool and previous literature. The data were compiled and analyzed using the RevMan 5.4 software. The results of this review confirm the previously published literature and have found rates of acute kidney injury (P = 0.05) and postoperative pacemaker insertion (P < 0.00001) favoring females and in-hospital mortality (P = 0.04), stroke (P < 0.00001), bleeding complications (P < 0.00001), and vascular complications (P < 0.00001) favoring males. The previously published literature has demonstrated consistently inferior outcomes for females undergoing heart valve surgery when compared to males. However, contemporary literature investigating sex differences after TAVR has found comparable outcomes for females. While the postoperative outcomes after surgical aortic valve replacement and TAVR are well established, the causal factors are still unidentified. Future studies utilizing matching based on preoperative characteristics and follow-up including collection of postoperative ventricular remodeling and prosthetic valve performance data will aid in elucidating the causal factors impacting outcomes for males and females after TAVR.

No abstract