Three-year survival among patients undergoing abdominal aortic aneurysm repair was superior for endovascular procedures vs open surgery, findings from a statewide, population-based study in California indicate.

The observational analysis, which involved 23,670 patients in California, was the first to compare how the two elective procedures fared in real-world surgical settings and the first to show a long-term survival advantage for endovascular aneurysm repair (EVAR) compared with open aneurysm repair (OAR) surgery, David C. Chang, PhD, of Massachusetts General Hospital in Boston, and colleagues reported in JAMA Surgery.

Previous clinical trials have showed a survival advantage for EVAR 30-days post surgery, but no advantage at one-year follow-up or beyond.


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Chang and colleagues analyzed data from the California Office of Statewide Health Planning and Development database on all residents who had either undergone OAR or EVAR for AAA from 2001 to 2009. Median follow-up was 3.3 years (interquartile range 1.4 to 5.7 years). EVAR was conducted in 51.7% of patients, with those undergoing the procedure significantly more likely to be older, nonwhite, male, and to have received treatment at a teaching hospital.

The study by Chang et al differs from previous studies in that it analyzed outcomes on a population level, rather than in a controlled-trial setting. In a controlled trial, patients are required to be healthy enough for random assignment to OAR, which could potentially result in a selection of lower-risk patients compared with the general population.”

Mortality Rates

Similar to findings from clinical trials, 30-day mortality rates were higher for patients who underwent OAR compared with EVAR (4.74% vs 1.54%). The survival benefit was also observed at 6-month (8.71% vs 5.04%), 1-year (10.91% vs 8%), and 3-year (19.93% vs 19.84%) follow-up.

However, at 4- and 5-year follow-up mortality rates were lower among OAR recipients than EVAR patients (24.82% vs 26.31% at 4 years, and 29.69% vs 32.05% at 5 years).

“Given that the major risk factor for AAA is smoking, this advantage would inevitably erode as cardiovascular disease, emphysema, and pulmonary malignancy exact their toll,” wrote the researchers. “After 3 years, mortality was higher for patients who had EVAR repair. We believe this is explained by the willingness of the surgeon to undertake EVAR repair in older patients knowing that the less invasive procedure is safer than open aortic repair.”

Reintervention

When mortality rates were removed from the denominator, 30-day readmission rates were similar between the OAR and EVAR groups  (8.49% vs 8.16%), the researchers found.

However, EVAR patients had consistently higher rates of re-intervention for aneurysm-related complications, such as leak, from as early as 6 months after the operation to as many as 5 years later. Patients in the OAR group consistently had higher rates of incisional hernia repair.

At 30-days, patients in the OAR group had higher rates of wound dehiscence than the EVAR group, a slightly lower rate of surgical site infections, similar rates of pneumonia, and slightly higher rates of sepsis.

One disadvantage of the current study is that the data was limited to 2001 to 2009. Therefore, it “may not reflect more recent practices including a greater proportion of younger patients undergoing EVAR repair, newer devices and greater experience with endovascular interventions, and development of optimal surveillance protocols, which may have altered the study outcomes,” according to the researchers

The authors concluded that EVAR patients might require fewer reinterventions in the future. “As the significance of type II endoleaks is reconsidered, and if new devices prove effective, it is likely that fewer interventions will be made for this complication, reducing the major difference in readmissions for aneurysm-related complications.”

Reference

  1. Chang DC, Parina RP, Wilson SE. Survival After Endovascular vs Open Aortic Aneurysm Repairs. JAMA Surg. 2015.doi:10.1001/jamasurg.2015.2644.