Invited commentary

Chahwan and colleagues have provided a valuable analysis of their single-center experience with abdominal aortic aneurysm (AAA) repair. Their review analyzes the short-term and intermediate-term results of standard open repair and endovascular repair (EVAR) performed using a wide variety of stent grafts and highlights several important areas that are of interest. Of particular note, the authors are to be congratulated on obtaining excellent results—particularly with open AAA repair—where they achieved a mortality rate of 3.5% compared with 2.7% for EVAR (P = NS).

With this low perioperative mortality rate for open repair and the relatively small sample size, the authors were able to negate any significant perioperative survival advantage for EVAR. This mirrors the results of the pivotal trials reported for the AneuRx1 (Medtronic, Minneapolis, Minn), Excluder,2 (W.L. Gore and Associates, Flagstaff, Ariz) and Zenith3 (Cook, Bloomington, Ind) devices. Only in studies that evaluated much larger patient populations could significantly lower perioperative mortality be demonstrated for endovascular repair.4

The current study did demonstrate significant advantages with respect to operative blood loss and hospital length of stay, again similar to the previously reported pivotal trials. These findings reinforce previously published analyses that indicate success in preventing aneurysm-related death can be achieved in appropriately selected patients using conventional open repair techniques. The increase in perioperative morbidity associated with open repair may ultimately be balanced by its increased durability. This is suggested by the authors’ finding of increased survival at the 3-year time point. Although this could not be related to increased aneurysm-related mortality in the EVAR group, and the overall survival curves did not vary significantly, the finding is interesting. Whether it implies the patients who underwent open repair received more thorough management of cardiac and other comorbid medical conditions or another more difficult-to-define cause cannot be determined from the current study.

The distribution of open and endovascular repair procedures is also interesting. In this population, considerably more patients were treated with open repair (n = 417) than with EVAR (n = 260). This appears to be in distinction to most published series, but may be a more accurate reflection of general practice during the decade being studied. The authors do note a trend toward increasing use of EVAR in their patient population. This has resulted in longer follow-up for patients treated by standard open repair. It is difficult to determine if this influenced the reported rates for reintervention because these are not analyzed by the type of repair performed.

Of concern in the analysis is the selection of the type of repair procedure performed. Although the authors suggest that they favored open repair for patients who were generally younger (on average 71 vs 74 years old), the patients treated with open repair did not appear to have an increased number of comorbid medical conditions. Whether this reflects a limitation of the analysis of comorbid factors that limits the ability to distinguish the extent of the comorbid disease or whether it is an accurate reflection of a truly equal distribution of disease between the two groups cannot be distinguished in the current analysis.

It is also interesting that average size of the aneurysms treated by standard open repair was significantly larger (6.0 cm) than the size of aneurysms treated using EVAR (5.4 cm). It is possible that the authors have different thresholds for performing aneurysm repair according to the technique that is going to be used. For patients in whom open repair is being considered, the threshold for repair with respect to maximum aortic diameter may be higher. Alternatively, larger aneurysms may not have anatomy suitable for endovascular repair and consequently open repair is necessary.

Ultimately, the equivalent survival curves between the open and endovascular repair groups suggest that patients can undergo EVAR and thereby reduce the perioperative blood loss, hospital length of stay, and recovery time, and still maintain longer-term survival that is equal to patients treated by open repair. This appears to be of particular relevance for octogenarians, in whom the increase in perioperative mortality for open repair appears to be most significant.