The Impact of Clinical Decision Making on Short- and Long-Term Outcome after AAA Treatment

The treatment options for an abdominal aortic aneurysm (AAA) include traditional open reconstruction and endovascular aneurysm repair (EVAR). EVAR was introduced in the 1990s, and the development of aortic endovascular devices has progressed significantly thereafter. The technique of open reconstruction, on the other hand, has remained principally the same since its introduction in the 1950s. Both treatment methods have advantages and limitations which may potentially affect the outcomes and treatment decisions.

The aim of this work was to evaluate the short- and long-term results and the influence of technical decisions in patients treated for an AAA at Tampere University Hospital between January 2005 and December 2013. Firstly, the possible association between endograft fixation level and a decline in renal function, in both the short and the long term, was studied. Endovascular device manufacturers have defined specific anatomic aortic criteria for each device, and one of the aims was to determine whether performing EVAR outside of these instructions for use (IFU) has a negative effect on outcomes. Additionally, the outcomes of EVAR and open reconstruction were compared. Finally, the safety and successful use of percutaneous closure of the access site during EVAR were evaluated. A total of 362 patients underwent standard EVAR, while 182 patients underwent open reconstruction for an unruptured AAA during the study period. Each of the studies included in this dissertation had its own exclusion criteria. Data were collected and analyzed retrospectively.

Of the patients who underwent EVAR, 74.6% received suprarenal fixation (SR) and the remaining 25.4% were treated with infrarenal fixation (IR). During the first postoperative week, a decline in renal function was seen more often after SR than after IR, but no difference was noticed thereafter during five years of follow-up. Patients with renal insufficiency at baseline had a decline in renal function at 5 years postoperatively more frequently after SR than after IR.

At least one IFU criterion was violated in 44.2% of the patients who were treated with EVAR. During the median follow-up of over six years, all-cause mortality, aneurysm-related mortality, the incidence of AAA rupture, and the incidence of graft-related adverse events were higher among the patients who were treated outside of the IFU. The most crucial aneurysm characteristics included neck angulation and neck length.

Perioperative mortality and long-term survival were similar in patients who were treated with EVAR and those treated with open reconstruction. The 30-day reintervention rate was higher in the open reconstruction group, but EVAR patients experienced more reinterventions during long-term follow-up. When only those EVAR patients who were treated outside of the IFU were compared with open reconstruction patients, no difference was observed in perioperative mortality and long-term mortality. The 30-day reintervention rate was also higher in the open reconstruction group in this subgroup analysis, while long-term reintervention rates favored open reconstruction.

A total of 443 access sites were analyzed in 258 patients. Percutaneous closure (Prostar XL, Abbott Vascular, Santa Clara, CA, USA) was used in 257 (58.0%) cases and open cutdown in 186 (42.0%) cases. Complication rates were similar between the closure methods. The success rate of percutaneous closure was 94.6%. Operator experience, common femoral artery calcification or diameter, BMI, or sheath size did not predict failure.

In conclusion, the use of suprarenal fixation was safe with respect to renal dysfunction at least in patients with normal renal function at baseline. Performing EVAR outside of the IFU had negative effects on outcomes. However, open reconstruction did not seem to result in better survival than did performing EVAR, as perioperative mortality and long-term survival were similar after EVAR and open reconstruction, and adherence to the IFU did not affect these outcomes. When evaluating a patient’s suitability for standard EVAR, the most crucial aneurysm characteristics regarding outcomes seemed to be neck length and angulation. Perioperative reinterventions were needed more often after open reconstruction, but the long-term reintervention rate was higher after EVAR. According to this work, the use of the Prostar XL was safe, and the use of the device also seemed to be feasible in the hands of inexperienced operators.