Kei Nakamoto

Non-Ischemic Heart Failure With Reduced Ejection Fraction Is Associated With Altered Intestinal Microbiota

BACKGROUND Research suggests that heart failure with reduced ejection fraction (HFrEF) is a state of systemic inflammation that may be triggered by microbial products passing into the bloodstream through a compromised intestinal barrier. However, whether the intestinal microbiota exhibits dysbiosis in HFrEF patients is largely unknown.Methods and Results:Twenty eight non-ischemic HFrEF patients and 19 healthy controls were assessed by 16S rRNA analysis of bacterial DNA extracted from stool samples. After processing of sequencing data, bacteria were taxonomically classified, diversity indices were used to examine microbial ecology, and relative abundances of common core genera were compared between groups. Furthermore, we predicted gene carriage for bacterial metabolic pathways and inferred microbial interaction networks on multiple taxonomic levels.Bacterial communities of both groups were dominated by the Firmicutes and Bacteroidetes phyla. The most abundant genus in both groups wasBacteroides. Although α diversity did not differ between groups, ordination by β diversity metrics revealed a separation of the groups across components of variation.StreptococcusandVeillonellawere enriched in the common core microbiota of patients, whileSMB53was depleted. Gene families in amino acid, carbohydrate, vitamin, and xenobiotic metabolism showed significant differences between groups. Interaction networks revealed a higher degree of correlations between bacteria in patients. CONCLUSIONS Non-ischemic HFrEF patients exhibited multidimensional differences in intestinal microbial communities compared with healthy subjects.

Clinical Significance of Pulmonary Arterial Capacitance Calculated by Echocardiography in Patients With Advanced Heart Failure

BACKGROUND Advanced left heart failure (HF) often accompanies post-capillary pulmonary hypertension related to RV afterload. Although pulmonary arterial capacitance (PAC), a measure of pulmonary artery compliance, reflects right ventricular (RV) afterload, the clinical utility of PAC obtained by echocardiography (echo-PAC) is not well established in advanced HF.Methods and Results:We performed right heart catheterization in advanced HF patients (n=30), calculating echo-PAC as stroke volume/(tricuspid regurgitation pressure gradient-pulmonary regurgitation pressure gradient). The difference between the echo-PAC and catheter-measured PAC values was insignificant (0.21±0.17 mL/mmHg, P=0.23). Echo-PAC values predicted both pulmonary arterial wedge pressure (PAWP) ≥18 mmHg and pulmonary vascular resistance ≥3 Wood units (P=0.02, area under the curve: 0.88, cutoff value: 1.94 mL/mmHg). Next, we conducted an outcome study with advanced HF patients (n=72). Patients with echo-PAC <1.94 mL/mmHg had more advanced New York Heart Association functional class, higher B-type natriuretic peptide plasma levels, larger RV and lower RV fractional area change than those with echo-PAC ≥1.94 mL/mmHg. They also had a significantly higher rate of ventricular assist device implantation or death, even after adjustment for indices related to HF severity or RV function during a 1-year follow-up period (P<0.01). CONCLUSIONS Decreased PAC as measured by echocardiography, indicating elevated PAWP and RV dysfunction, predicted poorer outcomes in patients with advanced HF.

Therapeutic Strategies of Refractory Heart Failure

Because of an increase in the aging society, heart failure is a social burden in modern society worldwide. The number of patients with refractory heart failure is also increasing. When patients show no improvement better than class III symptoms of heart failure, despite optimizing therapy including fluid removal, appropriate use of inotropes, and guideline-directed medical therapy, the indication of heart transplantation should be considered first. If there is no indication of heart transplantation, destination therapy may be an alternative for patients with refractory heart failure. Palliative care should be provided for all of the patients in this category.

Ratio of pulmonary artery diameter to ascending aortic diameter and severity of heart failure

BACKGROUND Treatment decisions in dilated cardiomyopathy (DCM) patients with severe heart failure (HF) and short clinical history are challenging because of the difficulty of determining HF stage or prognosis in the acute HF phase. We hypothesized that persistent decreased systemic or increased pulmonary arterial pressure, including in the sub-clinical phase, might affect the main pulmonary artery diameter (PAD), ascending aortic diameter (AoD), and their ratio (PAD/AoD). This study assessed AoD, PAD, and PAD/AoD by non-contrast computed tomography scans in DCM patients in the acute phase of HF and examined the association of these parameters with their clinical course. METHODS Of 261 screened individuals, we studied 110 consecutive hospitalized patients with DCM suspected of being in advanced stage of HF and 45 age-matched controls, assessing clinical data and later events (cardiac death or left ventricular assist device implantation). RESULTS Compared with controls, DCM patients had smaller AoD (26.6 ± 4.4 vs 30.6 ± 2.7 mm) and larger PAD (27.7 ± 3.5 vs 25.4 ± 2.8 mm) and PAD/AoD (1.05 ± 0.14 vs 0.83 ± 0.08; all p < 0.01). DCM patients with high PAD/AoD (median, > 1.05) had more frequent past HF hospitalizations, lower blood pressure, stroke volume, and ejection fraction, higher brain natriuretic peptide levels, smaller AoD, and similar PAD compared with patients with a low PAD/AoD. A higher PAD/AoD was associated with poorer outcomes even after adjusting for age, blood pressure, ejection fraction, or number of hospitalizations. CONCLUSION Assessment of AoD and PAD may have important clinical implications in determining whether DCM patients are in an advanced stage of HF with a poorer prognosis.