Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Distribution of substance P-like immunoreactive fibres and terminals in the medulla oblongata of the human infant

This study provides a detailed report of the distribution and density of substance P-like immunoreactive fibres and terminals within the human infant medulla. Seven brains with no signs of macroscopic alteration fixed usually within 24-48 h after death were used. Free floating transverse sections (50-60 microns) were then immunostained with a monoclonal antibody against substance P using the avidin-biotin-peroxidase technique. Morphologically three types of substance P-like immunoreactive fibres were observed: those with small varicosities of less than 1 micron, those with medium varicosities of 1-2 microns and those with large varicosities of 2-4 microns. Very dense substance P-like immunoreactivity was present within the spinal trigeminal nucleus, parts of the gracile and cuneate fasciculi and the paracommissural subnucleus of the solitary nucleus; dense substance P-like immunoreactivity was present within the dorsal nucleus of the vagus nerve, commissural, medial, dorsal, dorsolateral ventral and ventrolateral subnuclei of the solitary nuclear complex, parasolitary nucleus, raphe obscurus, inferior olivary complex (medial, dorsal, dorsomedial nuclei) and ventrolateral part of the dorsal reticular nucleus; moderate substance P-like immunoreactivity was present within the gelatinosus nucleus of the solitary tract, lateral reticular nucleus proper, intermediate reticular zone and parvocellular reticular nucleus; sparse substance P-like immunoreactivity was present within the hypoglossal nucleus, retroambigual nucleus and much of the reticular formation (dorsal, parvocellular, ventral gigantocellular, dorsal paragigantocellular nuclei): and very sparse substance P-like immunoreactivity was present within the nucleus ambiguus, medial vestibular nucleus and parts of the reticular formation (ventral, medial, gigantocellular, ventral gigantocellular, dorsal paragigantocellular nuclei). Substance P-like immunoreactivity was absent in the area postrema, intercalated nucleus, gracile and cuneate nuclei, in the epiolivary, subtrigeminal and parvocellular divisions of the lateral reticular nucleus, spinal vestibular nucleus, and in the solitary and pyramidal tracts. In several regions the substance P-like immunoreactive fibres formed distinct pericellular arrays around the somata and dendrites of neurons (hypoglossal nucleus, dorsal nucleus of the vagus nerve, retroambigual nucleus, intermediate reticular zone). The results indicate the high specificity of the localization of substance P in various structures of the brainstem and underline the presumed significance of this peptide in autonomic and sensorimotor functions of the brain.

Absence of immunoreactive vasoactive intestinal polypeptide in tissue from the lungs of patients with asthma

Vasoactive intestinal polypeptide (VIP) is a neuropeptide present in the nerve fibers of normal lungs, where it acts to relax bronchial smooth muscle. To determine its presence or absence in the lungs of patients with asthma, we examined lung tissue obtained at autopsy or lobectomy from five patients with asthma and nine without asthma. The avidin-biotin-peroxidase complex technique was used to stain tissue for immunoreactivity to VIP. At least 80 tissue sections from each patient were examined microscopically; the airway diameter ranged from 100 microns to 1.2 cm. Immunoreactive VIP was seen within nerves in more than 92 percent of the sections from the lungs of patients without asthma. No VIP was seen in any of 468 sections we could evaluate that were obtained from the lungs of patients with asthma. As a control for the nonspecific destruction of neuropeptides, immunostaining for substance P was also carried out. Abundant amounts of this neuropeptide were seen within nerves in tissue from the lungs of all patients. We conclude that in patients with asthma there is a loss of VIP from the pulmonary nerve fibers that may diminish neurogenically mediated bronchodilation. Whether this loss is a cause or a result of asthma is unclear.

Distribution of substance P-immunoreactive structures in the developing cat carotid body

The distribution of substance P immunoreactivity in the cat carotid body was examined at 4 different stages of development. Although substance P-immunoreactive fibers were present in the carotid body from before birth through to adulthood, glomus cells did not display substance P-immunoreactivity until the period between birth and 6 weeks postnatally. The time course of these morphological differences in substance P distribution in the cat carotid body parallel the maturational changes in the hypoxic ventilatory response, suggesting that substance P may play a role in these changes.

Ventromedial mesencephalic tegmental (VMT) projections to ten functionally different cortical areas in the cat: topography and quantitative analysis

The cortical projections of the ventromedial mesencephalic tegmentum (VMT) were studied in the cat by the retrograde transport of wheat germ agglutinin-conjugated HRP (WGA-HRP). The following cortical regions were injected: prefrontal, cingulate, motor, somatic sensory, auditory, primary visual, secondary visual, parasplenial, insular, and entorhinal. Labelled cells in the five component nuclei of the VMT (rostral linear, parabrachial pigmented, central linear, interfascicular, and paranigral nuclei) were counted and the numbers correlated with the total cell populations of the nuclei. In all experiments large numbers of cells were labelled in the VMT, particularly in the rostral linear and parabrachial pigmented nuclei. Following entorhinal cortical injections, significant labelling occurred in the interfascicular and central linear nucleus, although some cells of these nuclei were labelled in every experiment. The cells of the paranigral nucleus remained unlabelled in all experiments. Several hundred VMT cells were labelled in most experiments, over 1000 in the case of the parasplenial and over 2000 in the case of prefrontal injections. The most strongly labelled nucleus was the rostral linear, in which up to 36% of the total cell population could be labelled in a single experiment. These results indicate that the VMT of the cat is a major source of brainstem projections to the cerebral cortex and that all cortical areas are reached by this system. Although the projections to the prefrontal and limbic cortical areas are particularly prominent, there appears to be a consistent and significant projection to all areas. Further, the projection of the VMT to the cortex is topographically organized, indicating that the functional roles of the component nuclei of the VMT may be substantially different.