CHICAGO - When compared to earlier research, a new all-cause death rate study reports no increase in mortality in patients with early aortic aneurysm (AAA) disease. Between 2006 and 2011, a total of 634 patient cases from three distinct health care systems in Northern California were reviewed. Recruitment and enrollment were done through Stanford University's department of surgery in Stanford, Calif. on behalf of the Stanford AAA Disease Specialized Center of Clinically Oriented Research Investigators Details of the research appear in the November 2012 issue of the Journal of Vascular Surgery® published by the Society for Vascular Surgery®.
Matthew Mell, MD co-author and medical director of the Stanford Vascular Laboratory and Clinic said previous research had determined that all-cause mortality in AAA patients was excessive and equivalent to that associated with coronary heart disease. “These studies occurred largely before the current era of coronary heart disease risk factor management and no recent study before ours has examined contemporary mortality associated with early AAA disease where the aneurysm diameter is between 3 and 5 cm,” added Dr. Mell.
Aneurysm diameter, demographic information, comorbidities, medication history and plasma for biomarker analysis were collected at the beginning of the study. Eighty-eight percent of the participants were male; 81.6 percent were not current smokers; and 76.7 percent were taking statins. One-fourth of patients had diabetes. Patients’ ages were 76.4 ± 8.0 years and aortic diameter ranged from 3.86 ±0.7 cm.
Estimated one- to three-year survival was 98.2 percent and 90.9 percent, respectively. Factors independently associated with mortality included larger aneurysm size (hazard ratio, 2.12; 95 percent confidence interval (CI); 1.26-3.57 for diameter more than 4.0 cm) and diabetes (hazard ratio, 2.24; 95 percent CI, 1.12-4.47).
Survival status was determined at follow-up with a mean of 5.2 ±12 months (range, 1-51 months). Data were analyzed with t tests or X 2 tests where appropriate. Freedom from death was calculated via Cox proportional hazards modeling; the relevance of individual predictors on mortality was determined by log-rank test (adjusting for patient-level factors, health care system independently predicted mortality).
During follow-up 51 (8.0 percent) patients underwent AAA repair for clinical indications. Death occurred in 35 subjects during the study period. Cardiovascular disease was the cause of death in 37 percent of the patients and other diseases were the cause of death in 43 percent. The cause of death in 20 percent of the patients was unknown. Mean AAA diameter of those with unknown cause of death was no different than for those with a known cause of death (3.8 cm vs. 4.2 cm). Two AAA-related deaths occurred, both after repair.
“Our study has shown that with contemporary management of cardiovascular risk factors, the mortality of patients with small AAA’s approximates that of the general population and larger aneurysm diameters independently predicted an increased mortality risk,” said Dr. Mell. He added that patients with an AAA should be advised to stop smoking and statin medications should be considered.
Researchers added that despite this overall improvement, mortality rates may vary between different health care systems within the same region, suggesting that institutional factors may contribute to survival in early AAA disease. “Further research,” added Dr. Mell, “is warranted to determine important factors that contribute to improved survival in early AAA disease.”
About Journal of Vascular Surgery®
Journal of Vascular Surgery® provides vascular, cardiothoracic and general surgeons with the most recent information in vascular surgery. Original, peer-reviewed articles cover clinical and experimental studies, noninvasive diagnostic techniques, processes and vascular substitutes, microvascular surgical techniques, angiography and endovascular management. Special issues publish papers presented at the annual meeting of the Journal's sponsoring society, the
Society for Vascular Surgery®
The Society for Vascular Surgery® (SVS) is a not-for-profit professional medical society, composed primarily of vascular surgeons, that seeks to advance excellence and innovation in vascular health through education, advocacy, research, and public awareness. SVS is the national advocate for 3,750 specialty-trained vascular surgeons and other medical professionals who are dedicated to the prevention and cure of vascular disease.