The semantic priming project

10.3758/s13428-012-0304-zBehavior Research Methods4541099-111

Chronobiological patterns of acute aortic dissection

BACKGROUND: Chronobiological rhythms have been shown to influence the occurrence of a variety of cardiovascular disorders. However, the effects of the time of the day, the day of the week, or monthly/seasonal changes on acute aortic dissection (AAD) have not been well studied. METHODS AND RESULTS: Accordingly, we evaluated 957 patients enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2000 (mean age 62+/-14 years, type A 61%). A chi(2) test for goodness of fit and partial Fourier analysis were used to evaluate nonuniformity and rhythmicity of AAD during circadian, weekly, and monthly periods. A significantly higher frequency of AAD occurred from 6:00 AM to 12:00 noon compared with other time periods (12:00 noon to 6:00 PM, 6:00 PM to 12:00 midnight, and 12:00 midnight to 6:00 AM; P<0.001 by chi(2) test). Fourier analysis showed a highly significant circadian variation (P<0.001) with a peak between 8:00 AM and 9:00 AM. Although no significant variation was found for the day of the week, the frequency of AAD was significantly higher during winter (P=0.008 versus other seasons by chi(2) test). Fourier analysis confirmed this monthly variation with a peak in January (P<0.001). Subgroup analysis identified a significant association for all subgroups with circadian rhythmicity. However, seasonal/monthly variations were observed only among patients aged <70 years, those with type B AAD, and those without hypertension or diabetes. CONCLUSIONS: Similar to other cardiovascular conditions, AAD exhibits significant circadian and seasonal/monthly variations. Our findings may have important implications for the prevention of AAD by tailoring treatment strategies to ensure maximal benefits during the vulnerable periods

Aortic expansion after acute type B aortic dissection

Background: A considerable number of patients with acute type B aortic dissection (ABAD) treated with medical management alone will exhibit aortic enlargement during follow-up, which could lead to aortic aneurysm and rupture. The purpose of this study was to investigate predictors of aortic expansion among ABAD patients enrolled in the International Registry of Acute Aortic Dissection. Methods: We analyzed 191 ABAD patients treated with medical therapy alone enrolled in the registry between 1996 and 2010, with available descending aortic diameter measurements at admission and during follow-up. The annual aortic expansion rate was calculated for all patients, and multivariate regression analysis was used to investigate factors affecting the expansion rate. Results: Aortic expansion was observed in 59% of ABAD patients; mean expansion rate was 1.7 \ub1 7 mm/y. In multivariate analysis, white race (regression coefficient [RC], 4.6; 95% confidence interval [CI], 1.4 to 7.7) and an initial aortic diameter less than 4.0 cm (RC, 6.3; 95% CI, 4.0 to 8.6) were associated with increased aortic expansion. Female sex (RC, -3.8; 95% CI, -6.1 to -1.4), intramural hematoma (RC, -3.8; 95% CI, -6.5 to -1.1), and use of calcium-channel blockers (RC, -3.8; 95% CI, -6.2 to -1.3) were associated with decreased aortic expansion. Conclusions: White race and a small initial aortic diameter were associated with increased aortic expansion during follow-up, and decreased aortic expansion was observed among women, patients with intramural hematoma, and those on calcium-channel blockers. These data raise the possibility that the use of calcium-channel blockers after ABAD may reduce the rate of aortic expansion, and therefore further investigation is warranted

Long-term survival in patients presenting with type B acute aortic dissection : insights from the international registry of acute aortic dissection

BACKGROUND - Follow-up survival studies in patients with acute type B aortic dissection have been restricted to a small number of patients in single centers. We used data from a contemporary registry of acute type B aortic dissection to better understand factors associated with adverse long-term survival. METHODS AND RESULTS - We examined 242 consecutive patients discharged alive with acute type B aortic dissection enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2003. Kaplan-Meier survival curves were constructed, and Cox proportional hazards analysis was performed to identify independent predictors of follow-up mortality. Three-year survival for patients treated medically, surgically, or with endovascular therapy was 77.6\ub16.6%, 82.8\ub118.9%, and 76.2\ub125.2%, respectively (median follow-up 2.3 years, log-rank P=0.61). Independent predictors of follow-up mortality included female gender (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.07 to 3.71; P=0.03), a history of prior aortic aneurysm (HR, 2.17; 95% CI, 1.03 to 4.59; P=0.04), a history of atherosclerosis (HR, 2.48; 95% CI, 1.32 to 4.66; P<0.01), in-hospital renal failure (HR, 2.55; 95% CI, 1.15 to 5.63; P=0.02), pleural effusion on chest radiograph (HR, 2.56; 95% CI, 1.18 to 5.58; P=0.02), and in-hospital hypotension/shock (HR, 12.5; 95% CI, 3.24 to 48.21; P<0.01). CONCLUSIONS - Contemporary follow-up mortality in patients who survive to hospital discharge with acute type B aortic dissection is high, approaching 1 in every 4 patients at 3 years. Current treatment and follow-up surveillance require further study to better understand and optimize care for patients with this complex disease

Descending aortic diameter of 5.5 cm or greater is not an accurate predictor of acute type B aortic dissection

Objective: The risk of acute type B aortic dissection is thought to increase with descending thoracic aortic diameter. Currently, elective repair of the descending thoracic aorta is indicated for an aortic diameter of 5.5 cm or greater. We sought to investigate the relationship between aortic diameter and acute type B aortic dissection, and the utility of aortic diameter as a predictor of acute type B aortic dissection. Methods: We examined the descending aortic diameter at presentation of 613 patients with acute type B aortic dissection who were enrolled in the International Registry of Acute Aortic Dissection between 1996 and 2009, and analyzed the subset of patients with acute type B aortic dissection with an aortic diameter less than 5.5 cm. Results: The median aortic diameter at the level of acute type B aortic dissection was 4.1 cm (range 2.1-13.0 cm). Only 18.4% of patients with acute type B aortic dissection in the International Registry of Acute Aortic Dissection had an aortic diameter of 5.5 cm or greater. Patients with Marfan syndrome represented 4.3% and had a slightly larger aortic diameter than patients without Marfan syndrome (4.68 vs 4.32 cm, P = .121). Complicated acute type B aortic dissection was more common among patients with an aortic diameter of 5.5 cm or greater (52.2% vs 35.6%, P < .001), and the in-hospital mortality for patients with an aortic diameter less than 5.5 cm and 5.5 cm or greater was 6.6% and 23.0% (P < .001), respectively. Conclusions: The majority of patients with acute type B aortic dissection present with a descending aortic diameter less than 5.5 cm before dissection and are not within the guidelines for elective descending thoracic aortic repair. Aortic diameter measurements do not seem to be a useful parameter to prevent aortic dissection, and other methods are needed to identify patients at risk for acute type B aortic dissection