Seasonal and monthly variation in occurrence of hypertensive urgency

Chronologic and Climatic Factors of Acute Aortic Dissection: Study of 1642 Patients in Two Continents

BACKGROUND

The purpose of this study was to examine whether chronologic and climatic factors and lunar phases affect the onset of acute aortic dissection (AAD).

METHODS

The frequencies of AAD were analyzed with regard to the chronologic and climatic factors and lunar phases on the day when AAD occurred for 1642 patients with AAD from two aortic referral centers in the United States and China.

RESULTS

Mean age of patients was 51.6 ± 13.1 years, and 1260 (76.7%) were men. Dissection was type A in 1125 patients (68.5%) and type B in 517 (31.5%). Early mortality rate was 11.6% (190 of 1642), including 89 aortic ruptures before operation and 101 operative deaths. There was a winter peak in occurrence (33.6%, P < .01) with a relative risk of 1.519. In a week, the frequency was highest on Wednesday (15.5%) and Monday (15.2%), and lowest on Sunday (12.8%). Month-specific incidence was significantly inversely correlated to the mean temperature (rho = -0.650, P = .022) and directly correlated to the atmospheric pressure (rho = 0.706, P = .001). The proportion of type A dissection was significantly higher in the full moon phase compared with type B dissection (73.7% vs 66.9%, P = .012).

CONCLUSIONS

Acute aortic dissection exhibits significant chronologic variation in the frequency of occurrence, with a peak in winter and on Wednesdays, and nadir in summer and on Sundays. The incidence is significantly correlated to the mean temperature and atmospheric pressure. The proportion of type A dissection is higher in the full moon phase. These results are important for understanding the mechanisms involved in triggering AAD events and helpful for improving disease prevention and patient care.

Chronobiology of acute aortic rupture or dissection: a systematic review and a meta-analysis of the literature

OBJECTIVES

Identification and quantification higher risk incidence of aortic rupture or dissection (AARD) could be of clinical interest and improve preventive strategies.

BACKGROUND

Several studies and subsequent meta-analyses have shown chronobiologic variations in the timing of occurrence of myocardial infarction, stroke, and pulmonary embolism. Conversely, such evidences are currently lacking for AARD despite a number of studies available dealing with periodicity.

METHODS

MEDLINE, EMBASE, and Google Scholar databases were searched up to July 2013. Temporal variation in the incidence of AARD was analyzed including all studies analyzing seasonal, monthly, weekly, and circadian aggregations. Two authors independently reviewed and extracted data.

RESULTS

Forty-two studies for a total of more than 80 000 patients were included. Our results showed a significantly increased incidence of AARD in Winter (Chi-square 854.92, p < 0.001), with a relative risk (RR) of 1.171 (99% CI 1.169, 1.172), in December (Chi-square 361.03, p < 0.001), RR of 1.142 (99% CI 1.141, 1.143), on Monday (Chi-square 428.09, p < 0.001), RR of 1.214 (99% CI 1.211, 1.216), and in the hours between 6 am and 12 pm (Chi-square 212.02, p < 0.001), RR of 1.585 (99% CI 1.562, 1.609). Subgroup and sensitivity analyses confirmed the results of principal analyses.

CONCLUSIONS

Our data strongly support the presence of evident rhythmic patterns in the incidence of acute aortic events, characterized by significantly higher risk in Winter, in December, on Monday and between 6 am and 12 pm. Future studies are needed to better clarify the underlying mechanisms and clinical implications.