In a recently published study, the introduction of endovascular aneurysm repair (EVAR) into the management of ruptured abdominal aortic aneurysm (AAA) decreased the 30-day mortality in unstable patients. Authors Melissa Jones (Peter Lougheed Centre, Calgary, Canada) and colleagues write that such an emergency EVAR protocol “should be considered the first-line intervention for the appropriate patient”.
In the Journal of Vascular Surgery (JVS), Jones et al give an overview of the background to their study, underlining a “paucity of literature” to support the mortality benefit of EVAR on ruptured AAA. They also note that an EVAR-first strategy is recommended by the Society of Vascular Surgery (SVS), however this is rated a low-quality recommendation. To address these issues, Jones and colleagues write that an emergency EVAR protocol was introduced at the Peter Lougheed Centre, a tertiary care centre in Calgary, Canada, in 2004.
Furthermore, the investigators claim that there is no published literature on the longstanding outcomes of emergency EVAR protocols on 30-day mortality after EVAR. The present report, they write, represented 17 years of experience with the management of ruptured AAA incorporating EVAR. In their analysis, the investigators evaluated all adult patients with a ruptured AAA who underwent a surgical or endovascular intervention at the Peter Lougheed Centre between March 2001 and December 2018.
The researchers identified 376 patients with ruptured AAA between 2001 and 2018—75 preprotocol and 301 postprotocol—with a decreasing incidence of ruptured AAA during the study period. They report that the introduction of the protocol in 2004 was associated with increased EVAR use (63.6% vs. 6.7%; p<0.001).
Jones and colleagues reveal that patients managed according to the protocol were more frequently unstable (systolic blood pressure of ≤80mmHg, 46.5% postprotocol vs. 22.7% preprotocol; p<0.001), with a lower average systolic blood pressure (87.4mmHg postprotocol vs. 83.2mL/min preprotocol; p<0.001). In addition, they state that the risk-adjusted 30-day mortality was 23.2% with the emergency EVAR protocol, versus 35.8% preprotocol (p=0.0727).
Finally, the researchers outline the results of a subgroup analysis, which demonstrated improved 30- day mortality for unstable patients (systolic blood pressure of ≤80mmHg) at 38% (vs. 62.4% preprotocol introduction; p=0.019). A cumulative sum, they add, demonstrated worse-than-expected mortality outcomes in the preprotocol period, and stability of surgical performance over 15 years after protocol introduction.
“On reflection of a 17- year experience with EVAR for ruptured AAA, the implementation of an emergency EVAR protocol demonstrated stable surgical performance for all patients with a ruptured AAA and evidence of improved 30-day mortality for unstable patients with a ruptured AAA,” Jones et al conclude in JVS. EVAR has become a mainstay intervention since the protocol introduction, they write, adding that the overall incidence of ruptured AAA is declining despite an increase in comorbid patients.
In the discussion of their findings, the authors consider areas of future research. “Although this study focused on the impact of the emergency EVAR protocol on preprotocol and postprotocol 30-day ruptured AAA mortality, further investigation into operative details (time to the operating room, procedure length, blood loss, use of intra-aortic occlusion balloon), anatomic details (aneurysm size, neck characteristics), and comorbidities (heart disease, pulmonary disease) would help to characterise additional mortality risk factors for patients with a ruptured AAA,” Jones and colleagues suggest.