Day-of-week variability in the occurrence and outcome of aortic diseases: does it exist?

Acute aortic dissection and rupture are life-threatening cardiovascular emergencies usually associated with high mortality. In analogy with other major adverse cardiovascular events, there is considerable evidence that dissection and rupture of aortic aneurysms are not randomly distributed over time but demonstrate temporal variations. To explore the hypothesis of a weekly pattern in aortic dissection and rupture, we assessed the database of all hospital admissions of the region Emilia-Romagna (RER) region, Italy, between January 2000 and December 2006. The total sample consisted of 4,615 subjects (77% males, mean age 70±13 years). Of these, 2,760 (59.8%) were diagnosed for aortic dissection, and 1,855 (40.1%) for aortic rupture. Hypertension was present in 938 patients with dissection (34%) and in 441 patients with rupture (23.8%). Cases were grouped by day of week of onset of total cases, dissection and rupture, and clinical outcome, e.g., fatal/nonfatal. The 2 test for goodness of fit was used for statistical analysis on total population, dissection and rupture, and fatal/nonfatal subgroups. A weekly pattern, characterized by a decreasing frequency from Monday to Sunday, was shown for total cases (p<0.0001), and dissection subgroup (p<0.0001), but not for rupture subgroup (p=NS). The same pattern was observed both in hypertensive subjects (dissection: (p<0.0001); rupture: (p=0.044), and normotensive subjects (dissection: p<0.0001; rupture: p=NS). Fatal cases showed an opposite trend, although not statistically significant, characterized by a peak on Sunday and a trough on Monday, for dissection (p=NS). However, when analyzing fatal/non fatal subgroups according to weekdays (Monday-Friday) and weekends (Saturday-Sunday), there was a significant prevalence of fatal cases on weekends both for dissection (22.8% vs 15.5, p<0.0001), and rupture (47,88% vs 40,64%, p=0.003). Monday seems to be a critical day for the occurrence of acute cardiovascular diseases, e.g., cardiac arrest, sudden death, acute myocardial infarction (AMI), and stroke. It is possible that stress of commencing weekly working activities and biochemical factors associated with cardiovascular risk, such as measures of carbohydrate and lipid metabolism, less favourable on Monday compared with other days of the week, could play a role. As for aortic diseases, no previous study has examinated the weekly variation in risk for aortic rupture, and studies on aortic dissection did not give univocal results. However, we can expect that specific risk factors, such as morning surge in blood pressure, may play a leading triggering role on Monday especially for aortic dissection.