Splanchnic Nerve Modulation Effects on Surrogate Measures of Venous Capacitance

Patient Sex Impacts Volume Phenotypes and Hemodynamics in Chronic Heart Failure: A Multicenter Analysis

BACKGROUND

Quantitative methods have shown clinically significant heterogeneity in blood volume (BV) profiles in patients with chronic heart failure (HF). How patients' sex might impact this volume heterogeneity and its relationship to cardiac hemodynamics remains to be defined.

METHODS

Retrospective analysis of clinical and quantitative BV, plasma volume (PV) and red blood cell (RBC) mass data was undertaken across 3 medical centers. BV was quantitated using nuclear medicine I-131-labeled plasma albumin indicator-dilution methodology with cardiac hemodynamics obtained within 24 hours.

RESULTS

In an analysis of 149 males and 106 females, absolute BV was greater, on average, in males (6.9 ± 1.7 vs 5.0 ± 1.2 liters; P < 0.001); however, a wide range in BVs was demonstrated in both sexes (2.9-14.5 liters). Male sex was associated with higher prevalence of large (+ 25% of normal) BV and PV expansions (36% vs 15% and 51% vs 21%, respectively; both P < 0.001). In contrast, female sex was associated with higher prevalence of normal total BV (44% vs 27%; P = 0.005), PV (54% vs 27%; P < 0.001), hypovolemia (23% vs 11%; P = 0.005), and true anemia (42% vs 26%; P < 0.001). Cardiac hemodynamics differed by sex, but only modest associations were demonstrated between volume profiles and cardiac filling pressures.

CONCLUSIONS

Findings support unique intravascular volume profiles reflecting sex-specific differences in the prevalence and distributions of total BV, PV and RBC mass profiles in patients with chronic HF. This underscores the importance of recognizing patients' sex as a significant factor influencing volume homeostasis, which needs to be taken into account to individualize volume-management strategies effectively.

Heart Failure: a Punch from the Gut

PURPOSE OF REVIEW

This article seeks to elucidate the mechanisms underlying the bidirectional relationship between the gut and the heart, focusing on the pathophysiology of heart failure. We have previously demonstrated that Heart failure (HF) has significant effects on splanchnic vasculature and leads to key alterations in the gut microbiome, portending greater comorbidity with HF.

RECENT FINDINGS

A growing field of research is focused on the effects of a "leaky gut" in the development of disease across organ systems. The leaky gut hypothesis centers on intestinal epithelial barrier dysfunction causing increased permeability of the gut and subsequent alterations to gut composition by endotoxins and microbial metabolites. Changes in the quantities of metabolites including short-chain fatty acids, trimethylamine N-oxide and other amino acid metabolites, and various bile acid species have been shown to result in gut dysbiosis and worsening HF. The gut plays a highly significant role in HF prognosis and requires greater attention for future therapeutic interventions. Treatments targeting gut composition could have very beneficial effects on HF prognosis.