Endovascular Abdominal Aorta Aneurysm Repair

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Chris De Laet, Caroline Obyn

In 2005, the KCE published a first report on endovascular abdominal aorta aneurysm repair (EVAR).1 Recently, the College Voor Zorgverzekeringen (CVZ, the Netherlands) published an update on the effectiveness and cost-effectiveness of EVAR.2 In addition, the Ludwig Boltzmann Institut (LBI, Austria) evaluated the endovascular treatment of complex abdominal aorta aneurysms using more sophisticated devices (fenestrated EVAR).³

FINDINGS FROM THE KCE REPORT (2005)¹

An aortic aneurysm is the dilatation of a portion of the aorta, usually occurring in the abdominal region. It occurs more frequently in men and incidence increases with age. Rupture of an abdominal aorta aneurysm (AAA) is a dramatic event with high mortality. The annual mortality from rupture of an AAA is estimated at 700 per year in Belgium.1
When an aneurysm is detected before rupture, elective repair can be performed, either through open surgery or by less invasive endovascular repair using a stentgraft introduced through the femoral artery. Since the risk of rupture is associated with the diameter of the aneurysm, watchful waiting with regular screening is recommended for small aneurysms while for aneurysms larger than 5 to 5.5 cm repair is indicated.1
The 2005 KCE report concludes that, in comparison to open surgery, EVAR is associated with a lower mortality and morbidity in the immediate peri-operative period. However, in the following one to two years there is a catch-up of mortality in the frail patients that survived the initial intervention. In the end there is no significant difference in mortality or quality of life between both interventions, but EVAR is associated with five to six times more complications and re-interventions. Therefore, patients undergoing EVAR need a more intensive follow-up. In patients unfit for open repair, no statistically significant difference in mortality is observed between EVAR and watchful waiting. EVAR is not cost-effective compared to open surgery, mainly due to the high price of the stent and the re-interventions needed.
In general, the mortality is higher in centres performing few surgical or endovascular procedures.
The KCE report does not recommend a generalized introduction of EVAR, but rather a careful continuation of experimenting combined with a careful registration and follow-up of all AAA repairs both with open surgery and EVAR to gather more solid evidence. It also recommends that EVAR should only be performed in a limited number of centres with enough experience and volumes.

RECENT EVIDENCE

Systematic literature search by CVZ, the Netherlands²

In September 2013, CVZ published the results from a systematic literature search including several new trials and meta-analyses. Their results are consistent with the KCE findings from 2005: “EVAR clearly presents short-term benefits. Patients undergoing EVAR treatment have in the short term a better survival than with open surgery and a shorter stay in the intensive care unit. In the long term, however, the survival is equal when compared to open repair and EVAR is associated with more re-interventions.”

They also conclude that “...EVAR is unlikely to be cost-effective compared to open AAA repair or watchful waiting. EVAR generates more costs due to the high price of the stent, the number of re-interventions and the lack of increased survival.”

Furthermore, “...the results of the treatment of non-complex AAA vary between Dutch centres.” Because of this variation CVZ states that it is “...desirable that the medical profession develops protocols to refine indication and quality requirements for specialists and centres.”
Meanwhile, in May 2013, three Dutch professional organisations published a common document with guidance on indications, quality protocols and volume criteria.2 Centres which perform non-complex EVAR should perform at least 20 AAA repairs (open or EVAR) yearly and even more for complex fenestrated EVAR procedures.
In January 2013, nation-wide registration of all AAA repair procedures was started.

Evidence review on complex EVAR procedures by LBI, Austria³

This report gives “...an overview of the best available evidence on complex EVAR procedures with fenestrated or branched devices (fenestrated EVAR).” Cost-effectiveness is not assessed.

The report states that “...due to the uncontrolled study design of the case-series, no direct conclusions can be drawn on the efficacy of the intervention.” However, “none of the methods (open surgical repair, conventional endovascular repair or endovascular repair with fenestrated or branched devices) showed a survival benefit for patients.”

LBI concludes that “...the inclusion of these procedures into the hospital benefit catalogue is recommended with restrictions. Endovascular aneurysm repair using fenestrated or branched devices is recommended for patients unfit for open repair and with an aneurysm diameter of ≥5.5 cm, for who this intervention represents the only alternative of aneurysm exclusion. The intervention should only be carried out in specialised centres with a minimum annual volume of this intervention. Furthermore, it should be associated with acquisition of relevant data.”

CURRENT SITUATION IN BELGIUM

Since September 2009, non-complex EVAR has been reimbursed in the nomenclature, but for specific indications only, and with compulsory data registration. Based on the Minimal Hospital Data (RHM – MZG) we estimate the total number of elective AAA repairs (not ruptured) at approximately 1 500 per year. Over the years, the number of EVAR increased from 320 procedures in 2003 to approximately 900 in 2011, performed in 79 centres. In 2013 this is already 1 382 procedures (>90% of all AAA repairs). Many centres perform fewer than ten EVAR procedures each year.

Since March 2012, complex AAA repair (fenestrated EVAR) had been financed through conventions between NIHDI (RIZIV-INAMI) and fourteen vascular surgery centres, again including mandatory data registration. Approximately 40 of these interventions were performed in the first 18 months since its introduction.

REFERENCES

1. Bonneux L, Cleemput I, Vrijens F, Vanoverloop J, Galloo P, Ramaekers D. Elective endovascular treatment of the abdominal aortic aneurysm (AAA). Health Technology Assessment (HTA). Brussels: Belgian Health Care Knowledge Centre (KCE); 2005 22/11/2005. KCE Reports 23 Available from: https://kce.fgov.be/en/elective-endovascular-treatment-of-the-abdominal-aortic-aneurysm-aaa
2. College voor Zorgverzekeringen. Standpunt Gepast gebruik endovasculaire behandeling van de abdominale aneurysmata van de aorta. Diemen, Nederland: 2013.  Terug te vinden op: https://www.zorginstituutnederland.nl/publicaties/rapport/2013/09/26/gepast-gebruik-endovasculaire-behandeling-van-de-abdominale-aneurysmata-van-de-aorta
3. Ludwig Boltzmann Institut. Endovaskuläre Versorgung komplexer Aortenaneurysmen mit gefensterten oder verzweigten Prothesen. Wien, Austria: 2013 March 2013.  Available from: http://eprints.hta.lbg.ac.at/1004/1/DSD_69.pdf