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Population-Based Study of Incidence and Outcome of Acute Aortic Dissection and Premorbid Risk Factor Control: 10-Year Results From the Oxford Vascular Study
Study Questions:
What is the community-based incidence of acute aortic dissection (AAD), and what risk factors are associated with AAD?
Methods:
This community-based study examined incidence, risk factors, and outcomes of AAD, by following a mean of 92,728 individuals registered at nine general practice sites in the United Kingdom between 2002 and 2012.
Results:
There were a total of 174 acute aortic events in 155 patients in the study population, including 54 patients with 59 aortic dissections, with a total of 52 incident AAD events. Type A and B AAD occurred in 71% (37/52) and 29% (15/52) of patients, respectively. The mean age of patients with incident AAD was 72 ± 15 years, and 60% were male; history of hypertension was present in 67% (35/52), and prior smoking was reported in 62% (32/52). The overall incidence of AAD was 6 cases per 100,000 persons annually, with the mean age lower in men versus women (67 ± 15 vs. 79 ± 10 years, p = 0.002). In patients with subsequent AAD, premorbid blood pressure was poorly controlled despite 67% of patients being on antihypertensive medications; in the 5 years before AAD, 56% of blood pressures were >140/90 mm Hg, and 46% had at least one systolic blood pressure ≥180 mm Hg. Of the 52 incident AADs, 33 died during the study period, and 18 fatalities were at home or on arrival at the hospital (all type A). The 30-day and 5-year fatality rates were 56% and 65%, respectively. Type A (vs. type B) was associated with higher 30-day (73% vs. 13%) and 5-year mortality (77% vs. 33%). Patients surviving to discharge had high rates of survival at 5 years (86% for type A, 83% for type B). In the 5 years prior to the event, blood pressure was higher in patients with type A dissection who did not survive to hospital admission than those who did (systolic blood pressure 151 ± 19 vs. 138 ± 18 mm Hg, p < 0.001).
Conclusions:
This population-based study demonstrates that approximately one half of type A AAD patients die before hospital admission, suggesting that registries may substantially underestimate disease incidence and mortality. Further, poorly controlled hypertension is common in patients with subsequent AAD, and higher blood pressure is associated with increased prehospital mortality in patients with type A AAD.
Perspective:
This study significantly improves our understanding of the real-world incidence and clinical experience of AAD. Based on the study findings, approximately one half of type A AADs do not survive to hospital admission, suggesting that many prior studies may underestimate the incidence and rates of mortality of this disease. When these patients are included in analysis, the difference in 5-year survival between type A and B AAD is striking (77% vs. 33%). Importantly, the study demonstrates that blood pressure is strongly associated with AAD. The majority of premorbid blood pressure readings in AAD patients were poorly controlled despite 67% being treated with antihypertensive therapy, and increased prehospital mortality was noted in type A AAD patients who had higher premorbid blood pressure. These findings highlight the importance of achieving good blood pressure control in patients with hypertension and at risk of AAD.
Keywords: Incidence, Risk Factors, Hypertension, Smoking
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