By Todd Neale, Staff Writer, MedPage Today
Published: January 03, 2011
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
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Reinterventions and readmissions occur more frequently after endovascular abdominal aortic aneurysm (AAA) repair than after open repair — partly explaining why the early survival benefit seen with the endovascular approach disappears over time, researchers found.
A study of more than 45,000 Medicare patients who underwent elective AAA repairs over a three year period found that major and minor reinterventions were more common with endovascular repair (0.4 versus 0.2 per 100 person-years, P<0.001), according to Marc Schermerhorn, MD, of Beth Israel Deaconess Medical Center in Boston, and colleagues.
Ruptures were uncommon, but also occurred at a higher rate following endovascular repair (0.5 verus 0.1 per 100 person-years, P<0.001), the researchers reported in the January issue of the Journal of Vascular Surgery.
* Explain that among patients undergoing abdominal aortic aneurysm (AAA) repair, reinterventions and readmissions occur more frequently after endovascular versus open surgical repair.
* Note that these results partly explain why the early survival benefit seen with the endovascular approach disappears over time.
* Explain that ruptures were uncommon but also occurred at a higher rate following endovascular repair and had a 30-day mortality rate of 28%.
The findings likely provide at least a partial explanation for the erosion of the early survival benefit with the endovascular approach, Schermerhorn and co-authors suggested.
“The overall cumulative and long-term effect of these reinterventions and the higher rate of subsequent rupture after [endovascular repair] likely contribute to but do not fully explain the equalization of overall survival during the follow-up period after AAA repair,” the researchers wrote, “because 2% more deaths during follow-up were attributable to reinterventions and readmissions in the endovascular AAA repair (EVAR) group compared with open repair.”
They noted that age, congestive heart failure, and renal failure also likely contribute to the observed loss of survival benefit over time.
To look at the relationship between reinterventions and readmissions after initial AAA repair, Schermerhorn and his colleagues analyzed claims data from 45,652 Medicare beneficiaries who underwent elective AAA repairs from 2001 to 2004.
The median age of the participants was around 76. The most common comorbidities in the study patients were hypertension, chronic obstructive pulmonary disease, and peripheral aterial disease (PAD).
Through up to six years of follow-up, overall reinterventions or readmissions were slightly more common following endovascular repair (7.6 versus 7.0 per 100 person-years, P<0.001). The overall 30-day mortality rate with any reintervention of readmission was 9.1%.
Patients who underwent endovascular repair had more of the following outcomes (with rates per 100 person-years). All differences were significant at P<0.001:
* Ruptures: 0.5 versus 0.1, with a 30-day mortality rate of 28%
* AAA-related reinterventions: 3.7 versus 0.9, with a mortality rate of 6.2%
* Minor open reinterventions: 0.8 verus 0.5, with a mortality rate of 7.2%
* Major AAA-related interventions: 0.4 versus 0.2, with a mortality rate of 13.7%
Patients treated with the endovascular approach had fewer laparotomy-related reinterventions than patients treated with the open approach (1.4 versus 3.0 per 100 person-years) and fewer readmissions for bowel obstruction or ileus without surgery (2.0 versus 2.7) (P<0.001 for both).
Overall, reinterventions or readmissions accounted for 9.6% of all deaths following endovascular repair and 7.6% of deaths following open repair (P<0.001).
The authors noted some limitations of their study, including those inherent to the use of administrative data, such as coding error and lack of clinical detail. The researchers were also unable to consider anatomic differences among patients and how they may relate to the risk of reintervention or readmission within the study.
While patients with PAD were more likely to have a reintervention or readmission, they “did not identify prior surgical procedures for this condition, which may further predispose patients to some of the AAA-related reinterventions we used as outcomes,” the team wrote.
“Future work should attempt to identify predictors of reintervention or readmission to factor this into clinical decision algorithms,” Schermerhorn and co-authors concluded.
The study was supported by an NIH T32 Harvard-Longwood Research Training in Vascular Surgery grant.
Schermerhorn has received an unrestricted educational grant from Gore, is on the data safety monitoring board for Endologix, and is a consultant for Medtronic. One of his co-authors has received an unrestricted educational grant from Gore.
Primary source: Journal of Vascular Surgery
Giles K, et al “Thirty-day mortality and late survival with reinterventions and readmissions after open and endovascular aortic aneurysm repair in Medicare beneficiaries” J Vasc Surg 2010; DOI: 10.1016/j.jvs.2010.08.051.