Risk of supranormal left ventricular ejection fraction in patients with aortic stenosis

BACKGROUND

Cardiovascular events are increasing in patients with supranormal left ventricular ejection fraction (snLVEF). However, the effect of snLVEF in patients with aortic stenosis (AS) remains unclear, especially in patients with moderate AS.

HYPOTHESIS

This study aimed to evaluate the prognosis of mortality and heart failure (HF) in patients with LVEF ≥ 50% and moderate or severe AS.

METHODS

This retrospective study targeted patients with moderate or severe AS and LVEF > 50%. LVEF of 50%-65% was classified as normal LVEF (nLVEF, nEF group) and >65% as snLVEF (snEF group). AS severity was stratified based on the aortic valve area into moderate (1.0-1.5 cm²) and severe (<1.0 cm²). Primary outcomes included all-cause mortality and HF hospitalization.

RESULTS

A total of 226 participants were included in this study. There were 67 and 65 participants with moderate AS in snEF (m-snEF) and nEF groups (m-nEF), respectively, and 41 and 53 participants with severe AS in the snEF (s-snEF) and nEF groups (s-nEF), respectively. During the observation period (median: 554 days), the primary composite outcome occurred in 108 individuals. Cox hazard analysis revealed no significant differences among the four groups in primary composite outcomes. With respect to HF hospitalization, the adjusted hazard ratios (95% confidence intervals) with m-snEF as the reference were as follows: m-nEF, 0.41 (0.19-0.89); s-nEF, 1.43 (0.76-2.67); and s-snEF, 1.83 (1.00-3.35).

CONCLUSIONS

The risk of HF hospitalization for m-snLVEF was higher than m-nLVEF and not significantly different from s-nLVEF.

Investigation of effective invasive blood pressure control methods to prevent acute exacerbation of acute aortic dissection

BACKGROUND

Acute aortic dissection is associated with high mortality and increased risk of complications. Acute exacerbations have a relatively high frequency; however, the contributing factors are unclear. Blood pressure (BP) and heart rate control are important factors, but the ideal BP control strategy to prevent acute exacerbations under invasive arterial pressure monitoring remains unclear. Therefore, in this study, we aimed to determine the relationship between invasive arterial BP and the effects of acute exacerbation of aortic dissection.

METHODS AND RESULTS

This single-centre, retrospective, case-control study included 104 patients with a partial diagnosis of acute aortic dissection (Stanford type A or B) who were treated conservatively between September 2013 and September 2022. The patients were divided into exacerbation (acute exacerbation; n = 26) and stable (no acute deterioration) groups. The SBP trend (122.5 ± 13.1 vs. 116.6 ± 10.6 mmHg, respectively; P = 0.024) and mean BP trend (77.8 ± 5.8 vs. 74.4 ± 7.5 mmHg, respectively; P = 0.038) significantly differed between the two groups. The time to target BP was significantly longer in the exacerbation group (P = 0.036).

CONCLUSION

The exacerbation group did not achieve a mean SBP < 120 mmHg. Moreover, the importance of early BP reduction was demonstrated in the present study.

Evaluation of immune responses to inactivated influenza vaccines prepared in embryonated chicken eggs and MDCK cells in a mouse model

This study was initiated with the isolation of influenza A and B viruses from clinical throat swabs in both fertile chicken eggs (egg) and MDCK cells, which were used in subsequent vaccine production in the above two hosts. On the basis of haemagglutination-inhibiting (HI) tests, immune mouse sera from mice vaccinated with MDCK cell-derived vaccines revealed antigenic similarities among H3N2 or B viruses isolated in MDCK cells or eggs. Similarly, antiserum prepared by immunization with egg-derived H3N2 vaccine showed equivalent antigenicity between homologous and heterologous (MDCK cell-derived) viruses. In contrast, antigenicity of egg-derived B vaccines was differed somewhat from that of MDCK cell-derived vaccines, suggesting the occurrence of antigenic change due to passaging in eggs. The time-course of immune responses based on HI titres indicated that MDCK cell-derived vaccines elicited extremely high antibody levels. Also, it was evident that antibody production by MDCK cell-grown H3N2 vaccine was very similar to that of vaccine prepared from egg-grown viruses. These results were comparable to those of plaque neutralization tests, although antigenic differences between egg- and MDCK cell-derived challenge viruses were confirmed in the test with antiserum to MDCK cell-derived vaccine. Consistent with HI-antibody production, the immunogenicity of MDCK cell-derived B vaccine appeared to be low by plaque neutralization test, while immune responses in mice which received egg-derived vaccines were significantly higher than that of the former. Furthermore, immune responses confirmed in mice immunized with B virus vaccines prepared in eggs revealed slight antigenic differences between two viruses derived from their respective hosts. Nevertheless, through evaluation of immune responses, MDCK cell-derived influenza vaccines may be useful when weak immunogenicity of B virus vaccine is improved.

A novel strain, B/Gifu/2/73, differs from other influenza B viruses in the receptor binding specificities toward sialo-sugar chain linkage

We reported in a previous paper (1. Xu et al, J. Biochem., 115, 202-207, 1994) that every human influenza B virus isolate determined, including B/Lee/40, B/Setagaya/3/56, B/Tokyo/7/66, B/Kagoshima/1/68, B/Kanagawa/3/76, B/Ibaraki/2/85, B/Yamagata/16/88, and B/Bangkok/163/90, restrictively recognizes lacto-series gangliosides containing Neu5Ac alpha 2-6Gal linkage. We found in this study a novel strain, B/Gifu/2/73, that showed remarkable receptor binding specificities to both Neu5Ac alpha 2-3 Gal and Neu5Ac alpha 2-6Gal linkages of lacto-series gangliosides. The amino acid sequence of the hemagglutinin (HA) in strain B/Gifu/2/73 was compared with that of B/Lee/40, B/Ibaraki/2/85, B/Yamagata/16/88, and B/Bangkok/163/90. Substitution of His116, Ala121, Arg141, Pro211, His253, and His271 in the HA1 subunit of strain B/Gifu/2/73 for Asn116, Thr121, Gly141, Gln211, Gln253, and Gln271 in the HA1 of the four strains above was found, indicating that these amino acid changes in the HA1 of B/Gifu/2/73 may play an important role in recognition of Neu5Ac alpha 2-3Gal and Neu5Ac alpha 2-6Gal linkages in the receptor sialo-sugar chains.

Enzyme-linked immunosorbent assay of influenza specific IgA antibody in nasal mucus

An enzyme-linked immunosorbent assay of influenza HA specific IgA antibody in nasal mucus is described. This assay is very sensitive and only a minute quantity of nasal mucus is required.