Evidence of the impact of air temperature and pressure on cardiovascular morbidity is still quite limited and controversial, and even less is known about the potential influence of geomagnetic activity. The objective of this study was to assess impacts of air temperature, barometric pressure and geomagnetic activity on hospitalizations with myocardial infarctions and brain strokes. We studied 2,833 myocardial infarctions and 1,096 brain strokes registered in two Moscow hospitals between 1992 and 2005. Daily event rates were linked with meteorological and geomagnetic conditions, using generalized linear model with controls for day of the week, seasonal and long-term trends. The number of myocardial infarctions decreased with temperature, displayed a U-shaped relationship with pressure and variations in pressure, and increased with geomagnetic activity. The number of strokes increased with temperature, daily temperature range and geomagnetic activity. Detrimental effects on strokes of low pressure and falling pressure were observed. Relative risks of infarctions and strokes during geomagnetic storms were 1.29 (95% CI 1.19-1.40) and 1.25 (1.10-1.42), respectively. The number of strokes doubled during cold spells. The influence of barometric pressure on hospitalizations was relatively greater than the influence of geomagnetic activity, and the influence of temperature was greater than the influence of pressure. Brain strokes were more sensitive to inclement weather than myocardial infarctions. This paper provides quantitative estimates of the expected increases in hospital admissions on the worst days and can help to develop preventive health plans for cardiovascular diseases.
Background Antithrombotic therapy in patients with cardiovascular disease requires rapid translation of laboratory assessment of haemorrheological parameters in clinical cardiology practice. Both antiplatelet and anticoagulant agents, especially when used in combination, can potentially increase the risk of severe bleeding. The precise balance between thrombosis and hemorrhage is therefore pivotal to ensure optimal treatment results. Purpose To develop simple and reliable methods to control the haemorheological properties of the blood and to assess the risk of potential bleeding. Methods We assessed platelet aggregation parameters measured in vitro by laser aggregometry and optical trapping techniques in blood samples of 131 patients with coronary artery disease. Additionally, blood rheology and microcirculation parameters were assessed in vivo in the nail-fold area using the digital capillaroscopy system. Results We found a statistically significant correlation between the number of aggregated blood cells in vitro and the presence of aggregates in the blood capillaries in vivo. A significant correlation was also observed between red blood cells (RBC) aggregation time in vitro and capillary flow velocity in vivo. The most severe deterioration of the rheological properties was found in patients with diffuse atherosclerotic disease receiving combined antithrombotic therapy. Interestingly, optical examination of soft tissues surrounding the capillaries of the nail-fold area revealed the presence of micro-hemorrhages in patients with history of hemorrhagic complications on antithrombotic therapy (Fig. 1). Conclusion Novel methods of biomedical photonics applied for in vivo and in vitro assessment of the blood haemorrheological properties can provide important additional information on microcirculation parameters and optimize treatment in patients on antithrombotic therapy. Funding Acknowledgement Type of funding sources: None. In vivo nail-fold digital capillaroscopy
Early diagnosis of heart failure (HF) severity and prediction of acute decompensation is complicated due to the absence of specific symptoms and objective measurable criteria. Here we present a new indicator of the HF severity based on the soft tissue optical imaging in nail-fold capillaries. Material and methods One hundred and twenty nine (129) adults we enrolled in the study, including 79 patients with NYHA I–III functional classes of HF, and 50 healthy volunteers without history or risk factors for cardiovascular disease. All patients with HF underwent a standard clinical and laboratory examination including comprehensive echocardiography for evaluation of heart chambers and intracardiac haemodynamics, systolic and diastolic function of the left ventricle (LV). The left ventricular ejection fraction (LVEF) was estimated by the ratio of LV stroke volume (Doppler calculation of aortic systolic flow) to the LV end-diastolic volume (Simpson's method) according to the ESC recommendations for management of patients with HF. Vital digital capillaroscopy (VDC) of the nail-fold was performed in all patients and healthy volunteers following a 12-hour overnight fasting in a temperature-controlled room in the seated position and the left arm at heart level. Nail-fold capillaries and pericapillary tissue were assessed on fingers of the left hand gently fixed into the device using a digital capillaroscope equipped with a high speed CCD-camera. We used VDC to measure the linear size (in mm) of perivascular zone (PZ) around nail-fold capillaries. Two-photon tomography with fluorescence lifetime imaging (FLIM) was used to investigate PZ composition. Results We observed significant differences in the linear size of the PZ in patients with HF and control group. The absolute dimension of PZ strongly correlated with the functional class of HF and outperformed standard echocardiographic parameters used in evaluation of patients. Only in patients with moderate-severe HF (functional class III) there was an echocardiographic evidence of systolic LV dysfunction with reduced LVEF (42±12%). This was confirmed by the distribution of subjects in the control and HF groups by the PZ size and bivariate density analysis. FLIM confirmed that the PZ size is mostly determined by accumulation of extravascular free water. Results The simple measurement of the linear size of nail-fold perivascular zone has high sensitivity and specificity in identification of patients with different NYHA classes of HF. The positive predictive value of this parameter exceeds that for all other non-invasive parameters, namely, LVEF. Dimension of the PZ is determined by amount of extravascular free water as confirmed by the fluorescence lifetime imaging. This approach could be of interest for differential diagnosis of HF and monitoring its treatment, providing important possibility to predict HF decompensation with very early diagnosis of the interstitial fluid retention. Patient distribution: PZ size and LVEF Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Russian Science Foundation
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