Timothy S. Phan

Effects of organic and inorganic nitrate on aortic and carotid haemodynamics in heart failure with preserved ejection fraction

To assess the haemodynamic effects of organic vs. inorganic nitrate administration among patients with heart failure with preserved ejection fraction (HFpEF).

Beta‐Blocker Use Is Associated With Impaired Left Atrial Function in Hypertension

Background Impaired left atrial (LA) mechanical function is present in hypertension and likely contributes to various complications, including atrial arrhythmias, stroke, and heart failure. Various antihypertensive drug classes exert differential effects on central hemodynamics and left ventricular function. However, little is known about their effects on LA function. Methods and Results We studied 212 subjects with hypertension and without heart failure or atrial fibrillation. LA strain was measured from cine steady‐state free‐precession cardiac MRI images using feature‐tracking algorithms. In multivariable models adjusted for age, sex, race, body mass index, blood pressure, diabetes mellitus, LA volume, left ventricular mass, and left ventricular ejection fraction, beta‐blocker use was associated with a lower total longitudinal strain (standardized β=−0.21; P=0.008), and lower LA expansion index (standardized β=−0.30; P<0.001), indicating impaired LA reservoir function. Beta‐blocker use was also associated with a lower positive strain (standardized β=−0.19; P=0.012) and early diastolic strain rate (standardized β=0.15; P=0.039), indicating impaired LA conduit function. Finally, beta‐blocker use was associated with a lower (less negative) late‐diastolic strain (standardized β=0.15; P=0.049), strain rate (standardized β=0.18; P=0.019), and a lower active LA emptying fraction (standardized β=−0.27; P<0.001), indicating impaired booster pump function. Use of other antihypertensive agents was not associated with LA function. Conclusions Beta‐blocker use is significantly associated with impaired LA function in hypertension. This association could underlie the increased risk of atrial fibrillation and stroke seen with the use of beta‐blockers (as opposed to other antihypertensive agents) demonstrated in recent trials.

Aldosterone, inactive matrix gla-protein, and large artery stiffness in hypertension

Vascular calcification leads to increased large artery stiffness. Matrix gla-protein (MGP) is a vitamin K-dependent protein that inhibits arterial calcification. Aldosterone promotes vascular calcification and stiffness, but the relationships between aldosterone, MGP, and arterial stiffness are unknown. We studied 199 adults (predominantly older men) with hypertension. We assessed the relationship between levels of dephospho-uncarboxylated MGP (dp-ucMGP), aldosterone, and carotid-femoral pulse wave velocity (CF-PWV) using standard regression and mediation analyses. Plasma aldosterone was measured in a subgroup of subjects (nxa0=xa0106). Aldosterone was strongly associated with dp-ucMGP (standardized βxa0=xa00.50, Pxa0<xa0.001), which was independent of potential confounders (βxa0=xa00.37, Pxa0<xa0.001). Levels of dp-ucMGP were significantly associated with CF-PWV (βxa0=xa00.30; Pxa0<xa0.001), which persisted after adjustment for potential confounders (βxa0=xa00.25; Pxa0=xa0.004). Plasma aldosterone was also significantly associated with CF-PWV (standardized βxa0=xa00.21; Pxa0=xa0.035). However, in a model that included aldosterone and dp-ucMGP, only the latter was associated with CF-PWV. Mediation analyses demonstrated a significant dp-ucMGP-mediated effect of aldosterone on CF-PWV, without a significant direct (dp-ucMGP independent) effect. Our study demonstrates a novel independent association between high aldosterone levels and dp-ucMGP, suggesting that aldosterone may influence the MGP pathway. This relationship appears to underlie the previously documented relationship between aldosterone and increased arterial stiffness.

ACQUISITION OF TIME-RESOLVED BRACHIAL PRESSURE WAVEFORMS FROM CUFF-BASED PULSE VOLUME RECORDINGS

Background: Time-resolved brachial pressure (BP) waveforms are informative regarding pulsatile arterial hemodynamics. In contrast to technically-demanding arterial tonometry (AT), noninvasive cuff-based pulse waveforms recordings (PVR) can be acquired without special training. Although similar in

HEART-FEMORAL PULSE WAVE VELOCITY IS A STRONGER MARKER OF ARTERIAL AGING THAN CAROTID-FEMORAL PULSE WAVE VELOCITY

Background: Carotid-femoral pulse wave velocity (cfPWV) is considered one of the standard methods to estimate aortic stiffness. Its requirement of a technically-skilled operator has motivated development of automated systems to measure PWV. Heart-femoral PWV (hfPWV) can be automatically measured in

CARDIO-FEMORAL VASCULAR INDEX: A NEW MARKER OF ARTERIAL AGING

Background: Aortic stiffness (AS) is an important mediator of CVD risk with aging. Operator-independent methods to assess AS are needed. Cardio-ankle vascular index (CAVI) is a noninvasive estimate of AS that can be automatically measured with cuff-based systems. Its specificity to AS as a marker of