Minimally invasive elective repairs of abdominal aortic aneurysms, potential deadly bulges in arteries, reduces vessel rupture and short-term, AAA-related mortality, according to a Beth Israel Deaconess Medical Center study.
Endovascular abdominal aortic repair (EVAR), where surgeons use stents to repair damaged blood vessels, was first introduced in 1999 and has resulted in lower rates of death and complications than open surgical repair. It has allowed surgeons to offer the elective procedure for patients considered at too much risk for the traditional open repair and, when combined with increased detection, may be responsible for the increased numbers for repairs before the vessel ruptures.
Surgeons have been concerned, however, that EVAR may not be as effective in preventing late ruptures leading to potentially increased mortality after repair.
In a retrospective observational study of 338,278 Medicare patients undergoing intact repair between 1995 and 2008, BIDMC researchers found a decline in ruptures, with or without repair in all age groups, with a decline in operative mortality in both elective and emergent repairs. The study was published online by the Annals of Surgery.
“The introduction of EVAR, combined with advanced abdominal imaging, may be responsible for an increasing number of intact AAA repairs in the United States, which should ultimately result in lower mortality from AAA rupture,” says lead author Marc L. Schermerhorn, MD, Chief of the Division of Vascular and Endovascular Surgery within the Roberta and Stephen R. Weiner Department of Surgery at BIDMC and an Associate Professor of Medicine at Harvard Medical School.
The study found the overall rate of intact repair, adjusted for age and gender, increased from 79.9 to 85.0 per 100,000 Medicare beneficiaries during the study period. The rate decreased for those ages 65-74, but increased in all other age groups, particularly for those ages 80 and above.
The proportion of intact repairs using EVAR increased steadily over time, reaching 77 percent in 2008 for all age groups and 83 percent for patients over the age of 80.
Operative mortality with intact repair declined over time after the introduction of EVAR, with the greatest reduction for patients 80 and older. The overall rate of short-term AAA-related deaths for patients presenting at a hospital declined from 26.1 to 12.1 per 100,000 Medicare beneficiaries, mostly due to a 50 percent decline in the rate of ruptures and resulting deaths.
Schermerhorn noted several key findings, including a dramatic increase in intact AAA repairs in patients over 80 – and a decrease in those younger than 75. The study also found a 50 percent decrease in deaths due to ruptures from 1995 to 2008.
“Short-term AAA-related deaths in the US are decreasing due to both fewer deaths after intact repair … and decreased incidence of rupture,” says Schermerhorn, adding “the incidence of AAA may be declining in younger patients.”
But while the increase in intact repairs likely coincided with the introduction of EVAR, by expanding access to repair, particularly for the oldest patients “we cannot confirm that life expectancy has been prolonged meaningfully because although rupture may have been prevented, these patients may have died from other competing causes soon afterward.”
Co-authors include: Rodney P. Bensley, MD, Kristina A. Giles MD, Rob Hurks MD and Elliot Chaikof MD of the BIDMC Department of Surgery; Philip Cotterill, PhD, of the Centers for Medicare and Medicaid Services; A. James O’Malley PhD of the Department of Health Care Policy at Harvard Medical School and Bruce Landon, MD, MBA, of the BIDMC Department of Medicine and the Harvard Department of Health Care Policy.
Funding was provided by a grant from the National Institutes of Health Harvard-Longwood Research Training in Vascular Surgery. Schermerhorn is on the Endologix Data Safety and Monitoring Board and is a Medtronic consultant, Schermerhorn and Landon have received a Gore Unrestricted Educational Grant.
Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School, and currently ranks third in National Institutes of Health funding among independent hospitals nationwide. BIDMC is clinically affiliated with the Joslin Diabetes Center and is a research partner of Dana-Farber/Harvard Cancer Center. BIDMC is the official hospital of the Boston Red Sox.
“Changes in abdominal aortic aneurysm rupture and short-term mortality, 1995-2008: a retrospective observational study”, Schermerhorn ML, Bensley RP, Giles KA, Hurks R, Oʼmalley AJ, Cotterill P, Chaikof E, Landon BE.
Ann Surg. 2012 Oct;256(4):651-8. doi: 10.1097/SLA.0b013e31826b4f91
Source: Beth Israel Deaconess Medical Center