Barometric Pressure and the Incidence of Pulmonary Embolism

Season of delivery and risk of venous thromboembolism during hospitalization among pregnant women

Background

Seasons were found to be related to the occurrences of venous thromboembolism (VTE) in hospitalized patients. No previous study has explored whether seasons were associated with VTE risk in pregnant women. This study aimed to investigate the relationships between the season of delivery and VTE risk during hospitalization among pregnant women.

Methods

This is a multi-center retrospective cohort study of pregnant women. Participants were those who delivered at seven designated sites in Hubei Province, China, during the period from January 2017 to December 2022. They were categorized according to their season/month of delivery. Information on new-onset VTE during hospitalization was followed.

Results

Approximately 0.28% (104/37,778) of the pregnant women developed new-onset VTE during hospitalization for delivery. After adjustment, compared with participants in the spring group, participants in the summer, autumn, and winter groups had an increased risk of VTE during hospitalization. The ORs were 2.59 [1.30, 5.15], 2.83 [1.43, 5.60], and 2.35 [1.17, 4.75] for the summer, autumn, and winter groups, respectively. Pregnant women in the combined group (summer + autumn + winter) had an increased risk of VTE during hospitalization than those in the spring group (OR, 2.59 [1.39, 4.85]). By restricting the analyses among pregnant women without in vitro fertilization, gestational diabetes mellitus, and preterm, the results still remained robust. Compared with participants who delivered in March, April, and May, participants who delivered in June, July, September, November, December, and February had a higher risk of VTE during hospitalization.

Conclusion

This study demonstrated that pregnant women who delivered in summer, autumn, and winter had an increased VTE risk during hospitalization compared with those who delivered in spring.

Effect of atmospheric pressure changes on the development of pulmonary embolism: a retrospective analysis of 8 years of data

BACKGROUND

Pulmonary embolism (PE) is a condition with high mortality, and determining its etiology is as important as its treatment. There are limited studies in the literature examining the effect of atmospheric pressure (AP) change on PE.

OBJECTIVES

Analyze the effect of AP level and the change in AP level on the development of PE according to year, season and months.

DESIGN

Retrospective SETTING: Department of tertiary care center PATIENTS AND METHODS: Patients with diagnosed or presumed PE who were followed up in the Erzurum Atatürk University Medicine Chest Diseases Clinic between 2012 and 2020 (8 years) were retrospectively screened for inclusion in the study by examining hospital records. Daily AP values were obtained electronically through official correspondence with the Erzurum Regional Meteorological Directorate. Patients diagnosed with PE were recorded using the hospital database and anamnesis forms. The dates of admission to hospital were recorded. Risk factors leading to the development of PE were identified using the records.

MAIN OUTCOME MEASURES

Relationship between AP values and the incidence of PE.

SAMPLE SIZE

592 RESULTS: APmin, APmax, and APmean were significantly lower on days with PE cases compared to days without PE cases (P<.001 for all). ΔAPmin, ΔAPmax, and ΔAPmean values were all negative on days with PE, but only the difference in ΔAPmin was significant (P=.04).

CONCLUSIONS

This study showed that lower AP values were significantly associated with the incidence of PE. In particular, a drop in APmin compared to the previous day seemed to be most associated with PE development.

LIMITATIONS

Retrospective design and only applicable to region.

CONFLICT OF INTEREST

None.

The Impact of Winter Months on Venous Thromboembolism (VTE) Patients: A Retrospective Analysis of Hospital Outcomes in the United States

Objective: We aimed to analyze the Health Care Utilization Project’s (HCUP) Nationwide Inpatient Sample (NIS) and compare mortality rates in hospitals by month to determine if there is seasonal variability in outcomes associated with venous thromboembolism (VTE).

Methods: The Nationwide Inpatient Sample database was queried from 1998 to 2011. Inclusion criteria were a diagnosis of deep vein thrombosis (DVT) (ICD-9 {International Classification of Diseases, Ninth Revision, Clinical Modification} 453.4, 453.8) and/or VTE (ICD-9 415.1) in patients aged 18 years or more. Admission data was then analyzed to compare mortality rates in teaching and non-teaching hospitals over that time and by month. Demographics, Charlson Comorbidity Index, length of stay (LOS), hospital region, and admission types (emergent/urgent versus elective admissions) were assessed. Linear and logistic models were generated for complex survey design to analyze predictors of mortality and LOS.

Results: A total of 1,449,113 DVT/VTE cases were identified in the Nationwide Inpatient Sample (weighted n= 7,150,613), 54.7% female, 56.38% white, 49% in teaching hospitals. Higher mortality was found in the months of November 6.52%, December 6.9%, January 6.94%, and February 6.93% versus overall mortality of 6.4% over 12 months. Higher mortality was noted in these winter months in all regions, along with a significantly increased LOS. Mortality in the total cohort was found to be higher in January, with odds ratio (OR) 1.11 (1.08-1.15), p<0.0001; February, OR 1.11 (1.07-1.15), p<0.0001; and December, OR 1.10 (1.06-1.14), p<0.0001 compared to June. Mortality was significantly lower in the Midwest or North Central regions (OR 0.78 {0.72-0.83}, p<0.0001) and West (OR 0.80 {0.73-0.87}, p<0.0001) compared to the Northeast. Mortality was also significantly higher in teaching hospitals than in non-teaching hospitals (OR 1.16 {1.10-1.22}, p<0.0001), with mortality trending higher in teaching hospitals each month. Emergent/urgent admission, larger hospital size, female sex, age, and urban location were also significantly associated with increased mortality.

Conclusions: This national study identified an increased risk of mortality associated with hospitalizations for DVT/VTE in the winter months, independent of hospital teaching status or region.

Individual sensitivity of cold pressor, environmental meteorological factors associated with blood pressure and its fluctuation

Previous studies have examined the associations of meteorological factors with blood pressure; however, these associations have not fully elucidated, especially lacking of evidence from cohort study, little information about the associations of cold pressor sensitivity with blood pressure and its fluctuation. The objective of this study was to investigate the outdoor and indoor temperature, barometric pressure, humidity, and cold pressor sensitivity with blood pressure and its fluctuation. Forty-eight healthy subjects were recruited, and response of blood pressure to cold exposure was measured with cold pressor test (CPT). Then, all the subjects were followed up, and blood pressure was measured every half a month in a period of consecutive 12 months. Multiple panel analysis with random-effects generalized least squares (GLS) regression was used to analyze the effect of the outdoor and indoor temperature, barometric pressure, humidity, and response to cold pressor exposure on blood pressure. Outdoor and indoor temperature and humidity were found to be independently associated with blood pressure (all the P values < 0.05). The response to cold exposure positively associated with blood pressure and its fluctuation (P < 0.05). The subjects with higher cold pressor sensitivity had about 4.7 mmHg higher maximum difference of SBP in 1 year than the subjects with lower sensitivity. Outdoor and indoor temperature, humidity, and response to cold exposure are associated with blood pressure and its fluctuation. These findings provided extending evidence on blood pressure management in clinic and preventive practice.

Seasonal variation in the frequency of venous thromboembolism: An updated result of a meta-analysis and systemic review

Objective

Venous thromboembolism, including deep vein thrombosis and pulmonary embolism, is likely to cause the death of both medical and surgical patients. Despite some evidence of seasonal variation in the incidence of venous thromboembolism, the existing studies obtain contradictory results. A temporal pattern for pulmonary embolism is known, but data on deep vein thrombosis are inconclusive. The purpose of this study is to make a meta-analysis and systematically review the literature about seasonal variations of pulmonary embolism and/or deep vein thrombosis in order to objectively diagnose venous thromboembolism.

Methods

According to dichotomous data, risk ratios (RRs) and 95% confidence intervals (CIs) were used to compare the incidence of venous thromboembolism in different seasons. The research was classified according to pulmonary embolism mortality, pulmonary embolism/deep vein thrombosis incidence, latitude/elevation/climatic types, and monthly incidence for four subgroup comparisons. There were a total of 23 eligible studies, in which 40,309 patients with venous thromboembolism were compared.

Results

The pooled total venous thromboembolism incidence was 27.2% in winter, 23.1% in spring, 24.6% in summer, and 25.1% in autumn. According to the results of pooled analysis, the incidence of venous thromboembolism in winter was much higher than that in summer (RR = 1.12, 95% CI: 1.01–1.24, adjusted P = .04), especially deep vein thrombosis. Moreover, the incidence of venous thromboembolism in summer and autumn was lower than that in winter in low-latitude (<200 m) areas and median low-latitude (0–50°-N) areas. Interestingly, the frequency of pulmonary embolism mortality was the largest in spring and smallest in summer (spring > winter ≈ autumn > summer). For monthly data, a statistically significantly lower incidence of venous thromboembolism was observed in May and July than in October.

Conclusions

The study revealed a significantly higher incidence of venous thromboembolism and deep vein thrombosis in winter than in summer. Pulmonary embolism mortality occurred more frequently in spring than during other seasons. A statistically significantly lower incidence of venous thromboembolism was observed in May and July compared with that in October.

Update on Thrombolytic Therapy in Acute Pulmonary Thromboembolism

Thrombolytic treatment accelerates the dissolution of thrombus in acute pulmonary thromboembolism (PTE) and is potentially a lifesaving treatment. High-risk PTE is the clearest indication for this therapy, and its use in intermediate-risk cases is still controversial. A PTE response team may enable a rapid and effective determination of risk and treatment in these controversial clinical cases. Approved thrombolytic agents for the PTE treatment are streptokinase, urokinase, and alteplase. Currently, the most widely used agent is alteplase. It has a short infusion time (2 h) and a rapid effect. Newer, unapproved agents for the PTE treatment are tenecteplase and reteplase. The active resolution of thrombus via thrombolytic agents improves rapidly pulmonary perfusion, hemodynamic defect, gas exchange, and right ventricular dysfunction. However, it is important to determine appropriate candidates carefully, to prevent hemorrhage, which is the most important side effect of these drugs. Catheter-directed thrombolysis seems to be an alternative in patients not eligible for systemic thrombolytic therapy.

Effects of heat on first-ever strokes and the effect modification of atmospheric pressure: A time-series study in Shenzhen, China

BACKGROUND

Stroke is a leading cause of death globally. Extreme temperatures may induce stroke, but evidence on the effects of heat on first-ever strokes is not clear. Low air pressure can lead to depression and an increase in blood pressure, and it may exacerbate the health impact of heat. In this study, we aimed to evaluate the effects of heat on first-ever strokes, the possible sensitive populations, and the effect of modification of atmospheric pressure.

METHODS

We collected data on 142,569 first-ever strokes during 2005-2016 in Shenzhen, a coastal city in southern China, with subtropical oceanic monsoon climate. We fitted a time-series Poisson model in our study, estimating the association between daily mean temperature and first-ever strokes in hot months, with a distributed lag non-linear model with 7 days of lag. We calculated strokes attributable to heat in various gender, age groups, household register types, stroke subtypes, and atmospheric pressure levels.

RESULTS

Heat had a significant cumulative association with first-ever strokes, and the risk of strokes increased with the rise in temperature after it was higher than 30 °C (the 85th percentile). In total, 1.95% (95% empirical CI 0.63-3.20%) of first-ever strokes were attributable to high temperature. The attributable fraction and attributable number of heat were statistically significant in male, female, middle-aged and old patients, immigrant patients, and CBI patients. The fraction attributable to heat was 3.33% in the low atmospheric pressure group, and the number of estimated daily attributable strokes at low atmospheric pressure levels was higher than that of medium and high atmospheric pressure levels (p < 0.01).

CONCLUSIONS

High temperatures in hot months may trigger first-ever strokes, and low atmospheric pressure may exacerbate the effect. We mainly found associations between heat and first-ever strokes for intracerebral hemorrhage, middle-aged and old patients, as well as immigrant patients.

Relation of the frequency and mortality of pulmonary thromboembolism with meteorological parameters

Objective:The objective of this study is to find the relationship between incidence rate and mortality of acute pulmonary thromboembolism (PTE), and seasonal and meteorological factors. Materials and methods: The data from 234 patients who were hospitalized due to acute PTE in the emergency service or policlinics between 2001 and 2008 were investigated retrospectively. Cases that developed APE (acute pulmonary embolism) in the hospital were excluded. Seasons and months in which acute PTE was diagnosed were recorded. Mortality rates by months and seasons were evaluated. The mean pressure, temperature and humidity values were evaluated for periods of three days, seven days and one month before the day of presentation. The effects of meteorological factors on the severity (massive or non-massive) and mortality of APE were investigated. Results: The incidence rate of acute APE showed a significant difference according to seasons (p=0.000). APE was diagnosed most commonly in spring and winter. The mean pressure values for three days, seven days and one month and the mean humidity values for three days for the dead patients were found to be significantly lower than those of the survived ones (p<0.05). The mortality rate for patients admitted in summer was significantly higher than the rates for other seasons (p=0.02). There were no seasonal differences among the massive APE incidences. Mortality rates were higher in summer because of the nonmassive APE patients rather than the massive patients. Conclusion: Acute PE is a disease whose incidence and mortality rates are affected by meteorological factors. (www.actabiomedica.it)

Seasonal and monthly variability in the incidence of venous thromboembolism

Many studies showed that the occurrence of cardiovascular and cerebrovascular events exhibits a seasonal and monthly variation. Evidences of a seasonal and monthly variation in the incidence of venous thromboembolism (VTE) are more conflicting. We conducted a systematic review and a meta-analysis of the literature to assess the presence of an infradian rhythm of this disease. MEDLINE and EMBASE databases were searched up to January 2010. Monthly and seasonal variation in the incidence of VTE were analysed. We included studies analysing seasonal or monthly aggregation in the incidence of deep-vein thrombosis (DVT) and/or pulmonary embolism (PE) with an objective diagnosis of VTE. Two authors independently reviewed and extracted data. Seventeen studies for a total of about 35,000 patients were included. Twelve studies analysed the seasonal variation and 10 studies the monthly variation of VTE. Our results showed a significantly increased incidence of VTE in winter (chi-square 146.04, p <0.001), with a relative risk (RR) of VTE of 1.143 (99% CI [1.141, 1.144]), and a significantly increased incidence of VTE in January (chi-square 232.57, p <0.001) with an RR of VTE of 1.194 (99% CI 1.186, 1.203). Subgroup analyses including only idiopathic venous thromboembolic events confirmed the results of principal analyses. In conclusion, our data support the presence of an infradian pattern in the incidence of venous thromboembolic events, with a significantly higher risk in Winter and in January. Future studies are needed to better clarify the mechanisms behind this pattern.

Nature's wrath-The effect of weather on pain following orthopaedic trauma

BACKGROUND

Despite frequent complaints by orthopaedic trauma patients, to our knowledge there is no data regarding weather's effect on pain and function following acute and chronic fracture. The aim of our study was to investigate the influence of daily weather conditions on patient reported pain and functional status.

METHODS

We retrospectively examined prospectively collected data from 2369 separate outpatient visits of patients recovering from operative management of acute tibial plateau fractures, acute distal radius fractures, and chronic fracture nonunions. Pain and functional status were assessed using a visual analogue scale (VAS) and the DASH and SMFA functional indexes. For each visit date, the mean temperature, difference between mean temperature and expected temperature, dew point, mean humidity, amount of rain, amount of snow, and barometric pressure were recorded. Statistical analysis was run to search for associations between weather data and patient reported pain and function.

RESULTS

Low barometric pressure was associated with increased pain across all patient visits (p=0.007) and for patients at 1-year follow-up only (p=0.005). At 1-year follow-up, high temperature (p=0.021) and high humidity (p=0.030) were also associated with increased pain. No significant association was noted between weather data and patient reported functional status at any follow-up interval.

CONCLUSIONS

Patient complaints of weather influencing pain after orthopaedic trauma are valid. While pain in the immediate postoperative period is most likely dominated by incisional and soft tissue injuries, as time progresses barometric pressure, temperature, and humidity impact patient pain levels. Affirming and counseling that pain may vary based on changing weather conditions can help manage patient expectations and improve satisfaction.

Analysis of environmental risk factors for pulmonary embolism: A case-crossover study (2001-2013)

BACKGROUND

The relationship between environmental factors and pulmonary embolism (PE) has received little attention. The aim of this study was to estimate the influence of climatological factors and air pollution levels on PE in Spain from 2001 to 2013.

METHODS

We carried out a retrospective study. Data were collected from the Minimum Basic Data Set (MBDS) and the State Meteorological Agency (AEMET) of Spain. A case-crossover analysis was applied to identify environmental risk factors related to hospitalizations and deaths. For each patient, climatic and pollutant factors were assigned using data from the meteorological station closest to his/her postal code.

RESULTS

A seasonal effect for PE hospital admission was observed, with more frequent admissions noted during Spain's colder seasons with peaks in autumn and winter. Lower temperatures as well as higher concentrations of NO2 and O3 at the time of admission (when 2weeks and 3weeks respectively were used as controls) were significant risk factors for hospital admissions with PE.

CONCLUSIONS

Pulmonary embolism epidemiology was adversely influenced by colder climatological factors (absolute temperature, and seasonality) and higher concentrations of ambient air pollution (NO2, O3).

Dehydration as a Possible Cause of Monthly Variation in the Incidence of Venous Thromboembolism

BACKGROUND

Monthly or seasonal changes in the incidence of venous thromboembolism (VTE) were previously reported; however, the mechanism of such variability is not completely understood.

METHODS

In the present retrospective single-center analysis, consecutive patients with proximal deep vein thrombosis and/or pulmonary embolism (PE) diagnosed between January 2009 and December 2013 were evaluated.

RESULTS

The study population included 1496 patients, 48% men, mean age 63 ± 18 years. Most (82%) cases with VTE were provoked and 39% of patients had active cancer. Four months of peak incidence (3, 7, 10 and 11) were compared with 4 months of the lowest incidence (4, 5, 6, and 12), showing a significant difference in VTE numbers (597 vs 405 cases/year, P = 0.001). In all subgroup analyses, including gender, provoked or unprovoked event and presence or absence of cancer, significant differences between the months of peak and lowest incidence remained. Blood urea nitrogen (BUN)-creatinine ratio was significantly higher in all cases in the peak incidence group compared to the lowest incidence group (24 ± 1.5 vs 21 ± 1.6, P = 0.03). In patients with unprovoked VTE (n = 269), levels of BUN and hematocrit were significantly increased in the peak incidence group compared to lowest incidence group (19.5 ± 0.8 mg/dL vs 16 ± 1.1 mg/dL, P = 0.03; 39.2 ± 0.3% vs 37.4 ± 0.5%, P = 0.01, respectively).

CONCLUSIONS

The current study demonstrates that occurrence of VTE exhibits monthly variation also existing in patients with provoked events and even in those with cancer. Dehydration is suggested as a potential explanation to the month-related variation in incidence of VTE.

Evaluation of meteorological and epidemiological characteristics of fatal pulmonary embolism

The objective of the present study was to identify risk factors among epidemiological factors and meteorological conditions in connection with fatal pulmonary embolism. Information was collected from forensic autopsy records in sudden unexpected death cases where pulmonary embolism was the exact cause of death between 2001 and 2010 in Budapest. Meteorological parameters were detected during the investigated period. Gender, age, manner of death, cause of death, place of death, post-mortem pathomorphological changes and daily meteorological conditions (i.e. daily mean temperature and atmospheric pressure) were examined. We detected that the number of registered pulmonary embolism (No 467, 211 male) follows power law in time regardless of the manner of death. We first described that the number of registered fatal pulmonary embolism up to the nth day can be expressed as Y(n) = α ⋅ n (β) where Y denotes the number of fatal pulmonary embolisms up to the nth day and α > 0 and β > 1 are model parameters. We found that there is a definite link between the cold temperature and the increasing incidence of fatal pulmonary embolism. Cold temperature and the change of air pressure appear to be predisposing factors for fatal pulmonary embolism. Meteorological parameters should have provided additional information about the predisposing factors of thromboembolism.

Seasonal Changes in Hospital Admissions for Pulmonary Embolism in Metropolitan Areas of Tokyo (from the Tokyo Cardiovascular Care Unit Network)

Although several studies have shown the relation between temperature/atmospheric pressure and pulmonary embolism (PE), their results are inconsistent. Furthermore, diurnal temperature range (DTR) and diurnal pressure range (DPR) were not fully evaluated for their associations with hospital admissions for PE. Study subjects comprised cases of 1,148 PE treated at institutions belonging to the Tokyo Cardiovascular Care Unit Network from January 2005 to December 2012. Patient data were combined with a variety of daily local climate parameters obtained from the Japan Meteorological Agency. Every 1°C increase in the DTR at lag0 corresponded to an increased relative risk of hospital admission for PE (odds ratio [OR] 1.036, 95% confidence interval [CI] 1.003 to 1.070). In the cooler season (November to April), an increase of 1 hPa (barometric pressure) in the DPR at lag4 and lag5 was associated with an increased relative risk of hospital admission for PE (OR 1.042, 95% CI 1.007 to 1.077 and OR 0.952, 95% CI 0.914 to 0.992, respectively). An increase in the PE hospitalization rate was seen only in the cool season. Using a metropolitan database, we showed that DTR and DPR have different impacts on hospital admissions for PE. In conclusion, we found that an increase in the DTR increases the PE hospitalization rate, especially during the cooler season. The impact of DTR and DPR on PE incidence and related hospitalizations needs to be further evaluated.

Are Meteorological Parameters a Risk Factor for Pulmonary Embolism? A Retrospective Analysis of 530 Patients

BACKGROUND

The influence of meteorological conditions on cardiovascular morbidity and mortality has been known for a long time. However, few reports have been published on the influence of meteorological parameters on the occurrence of acute pulmonary embolism (PE).

AIMS

In this retrospective study, we compared the meteorological parameters between PE patients with risk factors and idiopathic PE patients.

STUDY DESIGN

Cross-sectional study.

METHODS

Medical documentation of 1180 patients with suspected acute pulmonary embolism diagnosed between January 2010 and December 2012 was retrospectively analyzed. A total of 530 patients with PE confirmed by computed tomography pulmonary angiography and/or ventilation/perfusion scan were included for further analysis. We divided the patients into two groups: PE with risk factors (provoked) and PE without risk factors (unprovoked). The meteorological data were collected from the relevant time period: temperature, humidity, pressure, and wind velocity. As the exact time of PE onset was unknown, the meteorological values attributed to each patient were the means of the values in the months or weeks at the time of diagnosis of PE.

RESULTS

The highest numbers of cases were seen in autumn (29.8%), followed by summer (28.9%), spring (22.1%), and winter (19.2%). In terms of months, the greatest number of cases occurred in June (57), followed by November (56) and October (54). Case distribution according to the months and seasons were statistically significant. The wind direction also affected the incidence of PE. There was a statistically significant positive correlation between case frequency and air temperature (r=0.300; p=0.031). No correlation was found between the unprovoked PE cases' monthly distribution and pressure, humidity, or temperature. However, there was a statistically significant positive correlation between the monthly distribution of the group with provoked PE cases and air temperature (r=0.586; p=0.045).

CONCLUSION

A statistically significant inverse correlation between atmospheric pressure and temperature and the number of all PE cases was observed in our study, which is in accordance with other reports. However, in unprovoked PE cases, there was no correlation between meteorological parameters and case incidence.

Trend and seasonality in hospitalizations for pulmonary embolism: a time-series analysis

BACKGROUND

The existence of seasonal variability in patients with acute pulmonary embolism (PE) has been debated for years, with contradictory results. The aim of this study was to identify the trend and possible existence of a seasonal pattern in hospitalizations for PE in Spain.

METHODS

We analyzed the hospital discharge database of the Spanish National Health System from 2001 to 2010. Patients aged > 14 years diagnosed with PE were selected and a time series was constructed considering mean daily admissions for PE by month. The trend and seasonality factor of the series were determined using time-series analysis, and time-series modeling was used for analysis. Exponential smoothing models and the autoregressive integrated moving average test were used to generate a predictive model.

RESULTS

From 2001 to 2010, there were 162,032 diagnoses of PE (5.07 per 1000 hospitalizations). In 105,168 cases, PE was the reason for admission. The PE diagnosis rate ranged from 4.14 per 1000 in 2001 to 6.56 per 1000 in 2010; and hospital admissions due to PE ranged from 2.67 to 4.28 per 1000 hospital discharges. Time-series analysis showed a linear increase in the incidence and a significant seasonal pattern with 17% more admissions in February and 12% fewer in June-July with respect to the central tendency (difference from February to June, 29%).

CONCLUSIONS

The incidence of hospitalizations for PE showed a linear increase and a seasonal pattern, with the highest number of admissions in winter and the lowest number in summer.

[Occurrence of acute cardiovascular diseases under different atmospheric parameters]

INTRODUCTION

Research on the effects of meteorological parameters on cardiovascular diseases may allow the development of novel prevention strategies.

AIM

The aim of the authors was to examine the correlation between meteorological parameters and the occurrence of acute cardiovascular diseases.

METHOD

A retrospective analysis was performed in 343 patients diagnosed with acute cardiovascular disease and treated at the Department of Vascular Surgery, Semmelweis University in 2010.

RESULTS

Acute cardiovascular diseases showed a seasonal variation with the highest occurrence in winter months (p = 0.0001). The daily increase of the events (n ≥ 3) were associated with front movements days (in 62.5% of cases). A significant correlation was found between the intraday temperature difference (p<0.0001), the intraday atmospheric pressure difference (p = 0.0034), the lowest maximum daily temperature (p<0.0001) and the occurrence of acute cardiovascular diseases. During the days with front movements 64% of the patients were older than 66 years of age. Among risk factors, hypertension showed front sensitivity.

CONCLUSIONS

Meteorological parameters are minor risk factors in the occurrence of acute cardiovascular diseases.

Is atmospheric pressure change an Independent risk factor for hemoptysis?

Objective: Hemoptysis is one of the most important and challenging symptoms in pulmonary medicine. Because of the increased number of patients with hemoptysis in certain periods of the year, we aimed to investigate whether atmospheric changes have an effect on the development of hemoptysis with or without a secondary cause.

Methods: The data of patients presenting with hemoptysis between January 2006 and December 2011 were analyzed. Data on the daily atmospheric pressure (hectopascal, hPa), relative humidity (%), and temperature (^o C) during that time were obtained.

Results: A total of 232 patients with hemoptysis, 145 male (62.5%) and 87 female (37.5%) with an average age of 48.1(±17.6), were admitted to our hospital between 2006 and 2011. The highest admission rates were in the spring season, the highest in May (n=37, 15.9%), and the lowest admission rates were in December (n=10, 4.3%). A statistically significant negative correlation was found between the number of hemoptysis cases and mean atmospheric pressure but no relative humidity or outdoor temperature.

Conclusion: Hemoptysis is very much influenced by weather factors; in particular, low atmospheric pressures significantly affect the development of hemoptysis. Fluctuations in atmospheric pressure may also play a role in hemoptysis.

Age-and sex-specific seasonal variation of venous thromboembolism in patients with and without family history: a nationwide family study in Sweden

Seasonal variation in venous thromboembolism (VTE) risk in individuals with familial predisposition to VTE has not been explored. This nationwide study aimed to determine whether there are age- and sex-specific seasonal differences in risk of hospitalisation of VTE among individuals with and without a family history of VTE. The Swedish Multi-Generation Register was linked to Hospital Discharge Register data for the period 1964-2010. Seasonal variation in first VTE events in 1987-2010 for individuals with and without a family history of VTE (siblings or parents) was determined by several independent methods. Stratified analyses were performed according to age, sex, and VTE subtype (pulmonary embolism [PE] or deep venous thrombosis [DVT]). Seasonal variation in VTE incidence, mostly with a peak during the winter, was observed in both sexes in individuals with and without family history with overall peak-to-low ratios (PLRs) of 1.15 and 1.21, respectively. The peak day was December 25 and February 1 for those with and without a family history of VTE, respectively. Seasonal variation was strongest among individuals aged >50 years. Among individuals aged 0-25 years with a family history, the peak for VTE was in July (PLR = 1.20). Significant seasonal variation was observed for PE and DVT with the exception of DVT among those with a family history (PLR = 1.01). In conclusion, our data support the presence of a modest seasonal variation of VTE among individuals with and without a family history of VTE. However, young age and family history may modify and attenuate the effect of season on VTE.

Winter cardiovascular diseases phenomenon

This paper review seasonal patterns across twelve cardiovascular diseases: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures.

Summer heat and mortality in New York City: how hot is too hot?

BACKGROUND

To assess the public health risk of heat waves and to set criteria for alerts for -excessive heat, various meteorologic metrics and models are used in different jurisdictions, generally without systematic comparisons of alternatives. We report such an analysis for New York City that compared maximum heat index with alternative metrics in models to predict daily variation in warm-season natural-cause mortality from 1997 through 2006.

MATERIALS AND METHODS

We used Poisson time-series generalized linear models and generalized additive models to estimate weather-mortality relationships using various metrics, lag and averaging times, and functional forms and compared model fit.

RESULTS

A model that included cubic functions of maximum heat index on the same and each of the previous 3 days provided the best fit, better than models using maximum, minimum, or average temperature, or spatial synoptic classification (SSC) of weather type. We found that goodness of fit and maximum heat index-mortality functions were similar using parametric and nonparametric models. Same-day maximum heat index was linearly related to mortality risk across its range. The slopes at lags of 1, 2, and 3 days were flat across moderate values but increased sharply between maximum heat index of 95 degrees F and 100 degrees F (35-38 degrees C). SSC or other meteorologic variables added to the maximum heat index model moderately improved goodness of fit, with slightly attenuated maximum heat index-mortality functions.

CONCLUSIONS

In New York City, maximum heat index performed similarly to alternative and more complex metrics in estimating mortality risk during hot weather. The linear relationship supports issuing heat alerts in New York City when the heat index is forecast to exceed approximately 95-100 degrees F. Periodic city-specific analyses using recent data are recommended to evaluate public health risks from extreme heat.

Cumulative effects of weather on stroke incidence: a multi-community cohort study in Japan

Background

Although seasonal variation in stroke incidence has been reported, it is not known whether year-long exposure to particular meteorological conditions affects the risk of stroke independently of conventional cardiovascular risk factors.

Methods

We conducted a cohort study involving 4849 men and 7529 women residing in 12 communities dispersed throughout Japan. Baseline data were obtained from April 1992 through July 1995. Follow-up was conducted annually to capture first-ever-in-life stroke events. Weather information during the period was also obtained for each community. Multilevel logistic regression analysis was conducted to evaluate the association between stroke incidence and each meteorological parameter adjusted for age, obesity, smoking status, total cholesterol, systolic blood pressure, diabetes, and other meteorological parameters.

Results

Over an average of 10.7 years of follow-up, 229 men and 221 women had stroke events. Among women, high annual rainfall (OR per 1000 mm, 1.46; 95% confidence interval, 1.05–2.03), low average ambient temperature (OR per 1 °C, 0.79; 0.66–0.94), and number of cold days per year (OR per 10 days, 3.37; 1.43–7.97) were associated with increased risk of stroke incidence, independent of conventional risk factors. Among men, number of cold days (OR per 10 days, 1.07; 1.02–1.12) was associated with an increased risk of stroke incidence, but the association became nonsignificant after adjustment for other risk factors. Similar results were obtained for cerebral infarction and cerebral hemorrhage.

Conclusions

Long-term exposure to some meteorological conditions may affect the risk of stroke, particularly in women, independent of conventional risk factors.

Atmospheric pressure changes and unexplained variability in INR measurements

Changes in atmospheric pressure may influence hepatic blood flow and drug metabolism. Anecdotal experience suggests international normalized ratio (INR) variability may be temporally related to significant atmospheric pressure changes. We investigated this potential association in a large sample of patients with multiple INRs. This is a retrospective review of outpatient anticoagulation records from the Iowa City Veteran's Affairs Medical Center and affiliated outpatient clinics from October 1999 to July 2007. All patients, receiving at least one prescription for warfarin and INR at least 30 days or more from the date of the first warfarin prescription, were identified. INRs during periods of hospitalization and vitamin K use were excluded. Proximity analysis using geocoding of ZIP codes of identified patients to the nearest National Oceanic and Atmospheric Administration station was performed to assign atmospheric pressure with INR. Spearman's Rho and Pearson's correlation were used to evaluate atmospheric pressure and INR. Unique patients (1441) with 45 187 INRs were analyzed. When limited to nontherapeutic INRs following a previously therapeutic INR (1121 unique patients/5256 INRs), a small but clinically insignificant association between delta INR and delta atmospheric pressure was observed (r = -0.025; P = 0.038), but not for actual INR and atmospheric pressure (P = 0.06). Delta atmospheric pressure demonstrated greater variation during fall/winter months compared with spring/summer (0.23 vs. 0.15 inHg; P < 0.001); however, variability in INRs for the corresponding seasons was not significant (P = 0.136). No significant difference was detected in the proportions of nontherapeutic INRs among the different seasons (P = 0.371). No correlation was observed between atmospheric pressure changes and INR variability. These findings refute the anecdotal experience seen in our anticoagulation clinic.

Comparison of clinical characteristics and outcomes of patients with COPD exacerbation with or without venous thromboembolism

BACKGROUND

Although some studies evaluated venous thromboembolism (VTE) prevalence in patients with chronic obstructive pulmonary disease (COPD), they contain no detailed description of the patients' characteristics.

OBJECTIVES

It was the aim of this study to investigate the frequency and clinical characteristics and outcomes of VTE in patients with COPD exacerbation.

METHODS

Between October 2004 and February 2005, 120 consecutive patients were included in the study. On admission, Doppler examination of lower extremities in all cases and spiral computed tomography of the thorax in cases with a suspicion of pulmonary thromboembolism were performed. A questionnaire was used to take a detailed history. In addition to routine laboratory tests, chest X-ray, postbronchodilator spirometry, arterial blood gas analysis and serum levels of D-dimer and C-reactive protein were evaluated, as well as dyspnea score and performance status before exacerbation. The hospitalization durations and mechanical ventilation requirements were also recorded.

RESULTS

VTE was determined in 16 cases (13.3%). In patients with VTE, the travel history was higher (p < 0.001), the dyspnea score worse (p = 0.005), the duration of hospitalization longer (p < 0.001) and the mechanical ventilation requirement increased (p < 0.001); a change in mental status was highly associated with the presence of VTE (p < 0.001).

CONCLUSIONS

It seems that VTE occurrence was higher in the presence of a risk factor causing immobility such as travel history and increased dyspnea. The cases with severe disease are more likely to have VTE. Preventive measures may be considered in such patients because their hospitalization stay and mechanical ventilation requirement are increased.