Atmospheric Pressure and Abdominal Aortic Aneurysm Rupture: Results From a Time Series Analysis and Case-Crossover Study

Does altitude increase the risk of traumatic aortic injuries? A retrospective cohort study among six level I trauma centers in the United States

Background

Traumatic aortic injuries (TAIs) are rare but are associated with a high mortality. Prior studies have shown skiers and pilots, whose injuries occur at high altitudes, are at an increased risk for a TAI. The purpose of this study was to examine the effect of altitude on the incidence of TAIs across all causes of injury.

Methods

This retrospective cohort study at six Level I trauma centers (8/1/2016–1/1/2020) included adult blunt trauma patients with a chest or abdomen injury. High altitude injuries (> 5000 ft.) were compared to low altitude injuries (≤ 5000 ft.). The primary outcome was incidence of TAI.

Results

There were 8562 patients, 37% were at high altitude and 63% at low altitude. High altitude patients were older (p < 0.01), more often Caucasian (p < 0.01) and had a higher ISS (p < 0.01). There was a significantly greater incidence of TAI at high altitude than low altitude (1.5% vs. 1.1%, p = 0.01). The median altitude was significantly higher for patients with a TAI than for patients without a TAI (5100 ft. vs. 1400 ft., p = 0.01). After adjustment, high altitude patients had 2-fold [OR: 2.4 (1.6, 3.7)] greater odds of having a TAI than low altitude patients.

Conclusion

TAIs were more prevalent among high altitude injuries. Providers should be aware of the increased incidence of TAIs at high altitudes particularly when there is a delay in diagnosis and transfer to a trauma center with appropriate resources to manage these critical injuries. TAI screening at high altitude trauma centers may improve survival rates.

Climatic influence on the risk of abdominal aortic aneurysm rupture

Our aim is to examine the effects of climatic conditions on the incidence of ruptured abdominal aortic aneurysms (rAAA) in Catalonia, Spain. We combined clinical data from the Public Health official registries in Catalonia, Spain (HD-MBDS) of all rAAA with local climatic data obtained from the closest meteorological station (69 stations, National Meteorological Service: MeteoCat) from 2008 to 2017. We analyzed the median, maximum, minimum, and variability of atmospheric pressure (hPa) and air temperature (°C), solar irradiation (MJ/m²), humidity (%), accumulated precipitation (mm), median wind, and maximum flaw direction and velocity (°, m/s), recorded on the days of events, the previous day, and mean results for 3, 7, and 30 days before, as well as seasonality. Seventy-five control days were randomly selected in a 1-year period around every rAAA day at the same meteorological station, and compared. A total of 717 days and locations with rAAA were identified, and 53,775 controls were randomly selected. For the rAAA days, there were significantly lower temperatures, lower solar global irradiation, and higher mean humidity levels in all time periods (p < 0.001, p < 0.001, p < 0.05); higher atmospheric pressure variability during 1 week and 1 month before (p = 0.011, p = 0.007); and they often occurred during autumn/winter (57.6%, p < 0.001). Logistic regression identified low mean temperatures on the days of ruptures and high mean humidity the week before as independent rupture predictors. In conclusion, low median temperatures the same day and high humidity during 1 week before were identified as independent predictors of rAAA occurrence. The role of climate on pathophysiologic mechanisms may require further investigation.

Seasonal incidence of ruptured abdominal aortic aneurysm and the influence of atmospheric pressure: a systematic review and meta-analysis

Ruptured abdominal aortic aneurysm (rAAA) is a life-threatening condition with a high mortality rate. Seasonal variations in the incidence of rAAA and the influence of atmospheric pressure have been studied throughout decades; however, the conclusions are contradictory. Therefore, we aimed to conduct a meta-analysis and systematic review of literature on seasonal variations in rAAA incidence and the influence of atmospheric pressure. Studies investigating seasonal variations in rAAA incidence and influence of atmospheric pressure were retrieved. For dichotomous data, we generated risk ratios (RRs) and 95% confidence intervals (CIs) for rAAA incidence compared among seasons. The studies were subdivided according to latitude, elevation, and climatic types, for subgroup comparisons. Studies reporting monthly incidence and seasonal mortality were further investigated. For continuous data, standardized mean differences (SMDs) and 95% CIs were generated for atmospheric pressure comparisons. Twenty-four eligible studies were included, comprising a total of 38,506 patients with rAAA. Pooled rAAA incidence was 25% in spring, 23% in summer, 26% in autumn, and 26% in winter. Pooled analysis demonstrated a statistically significant higher rAAA incidence in winter than in summer (RR 1.10, P = 0.04) and in autumn than in summer (RR 1.11, P < 0.00001). However, there was no statistically significant difference among other seasons. In the study of the influence of atmospheric pressure, no statistically significant difference was observed. In conclusion, our study revealed a higher incidence of rAAA in autumn and winter than in summer; however, atmospheric pressure was found to exert no influence.

Effects of atmospheric pressure dynamics on abdominal aortic aneurysm rupture onset

BACKGROUND

The effect of atmospheric pressure (AP) on the onset of abdominal aorta aneurysm rupture (RAAA) remains an unanswered question. We have investigated the seasonal variation and the effect of AP dynamics on RAAA by analysing the largest series of intraoperatively confirmed RAAA.

PATIENTS AND METHODS

To realize this study we have performed a retrospective analysis of 546 patients with RAAA, operated within 503 days at the Clinic for vascular and endovascular surgery CCS between 1.1.2003 and 31.12.2012. AP data for Belgrade city were obtained from meteorological yearbooks published by the Republic Hydrometeorological Service of Serbia measured at the hydrometeorological station "Belgrade Observatory". Only patients with a residence within the extended Belgrade region, exposed to the similar AP values, were included in the analysis of the AP effect on RAAA.

RESULTS

RAAA were observed more frequently during winter and autumn months but without significant difference in comparison to other seasons. Months with higher AP values were associated with a higher RAAA rate (p = 0.0008, R2 = 0.665). A similar trend was observed for the monthly AP variability (p = 0.0311, R2 = 0.374). Average AP values did not differ between days with and without RAAA. However, during the three and seven days periods preceding RAAA AP variability parameters were greater and AP was rising.

CONCLUSIONS

Although these pressure differences are very small, higher AP values over longer periods of time as well as greater variability are associated with RAAA. The exact mechanism behind this association remains unclear. The postulation that low AP may precipitate RAAA based on the Laplace law should be discarded.