BAV linked to different risk for aortic dissection than general population
MedWire News: Patients with bicuspid aortic valve (BAV) have a low incidence of aortic dissection but their risk is still significantly higher than that of the general population, a study suggests.
"Our study provides new data on long-term BAV outcomes that is both reassuring and a cause for careful monitoring of these patients," report Hector Michelena (Mayo Clinic, Rochester, Minnesota, USA) and co-authors in JAMA.
BAV is the most common congenital heart defect, and is linked to serious complications such as aortic dissection, which is in turn associated with high mortality, they explain. Aortic dissection can also occur in patients with undiagnosed BAV.
Michelena and team therefore analyzed the long-term follow-up data of residents in Olmstead Country, Minnesota, who were diagnosed with BAV using echocardiography between 1980 and 1999. They then searched for aortic complications of patients whose BAV had gone undiagnosed.
The study included 416 patients who were followed-up for an average duration of 16 years.
The findings revealed that aortic dissection occurred in 2 of the 416 patients, corresponding to an incidence of 3.1 cases per 10,000 patient-years and an age adjusted relative risk of 8.4 compared with the county's general population (p=0.003).
"Despite this high relative risk, the absolute incidence of aortic dissection remains very low," write the authors.
In patients aged 50 years or older or those who had aortic aneurysms at baseline, the incidences of aortic dissection were 17.4 and 44.9 cases per 10,000 patient-years, respectively.
A comprehensive search for aortic dissections in undiagnosed bicuspid valves revealed two additional patients, allowing an estimation of aortic dissection incidence in BAV patients irrespective of diagnosis status (1.5 cases per 10,000 patient-years) which was similar to the diagnosed BAV patients, the researchers report.
Of the 384 patients without aneurysm at baseline, 49 developed aneurysm at follow-up, corresponding to an incidence of 84.9 cases per 10,000 patient-years, and an age-adjusted relative risk of 86.2 compared with the general population (p<0.001)
The dissection incidence was higher in those patients over the age of 50 years, and those who experienced aneurysms, which emphasizes the significance of close monitoring and guideline implementation in these groups, say Michelena et al.
"Research efforts should concentrate on elucidating biological pathways of BAV aortopathy amenable to medical treatment, as well as identifying nonsize markers for refining risk prediction of aortic dissection in these patients."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Piriya Mahendra