Risk Models in Abdominal Aortic Aneurysm Surgery; Useful for Policy Makers or Patients?

Results of Open and Endovascular Abdominal Aortic Aneurysm Repair According to the E-PASS Score

Introduction:

Endovascular repair (EVAR) of abdominal aortic aneurysm has become the standard of care due to a lower 30-day mortality, a lower morbidity, shorter hospital stay and a quicker recovery. The role of open repair (OR) and to whom this type of operation should be offered is subject to discussion.

Objective:

To present a single center experience on the repair of abdominal aortic aneurysm, comparing the results of open and endovascular repairs.

Methods:

Retrospective cross-sectional observational study including 286 patients submitted to OR and 91 patients submitted to EVAR. The mean follow-up for the OR group was 66 months and for the EVAR group was 39 months.

Results:

The overall mortality was 11.89% for OR and 7.69% for EVAR (P=0.263), EVAR presented a death relative risk of 0.647. It was also found a lower intraoperative bleeding for EVAR (OR=1417.48±1180.42 mL versus EVAR=597.80±488.81 mL, P<0.0002) and a shorter operative time for endovascular repair (OR=4.40±1.08 hours versus EVAR=3.58±1.26 hours, P<0.003). The postoperative complications presented no statistical difference between groups (OR=29.03% versus EVAR=25.27%, P=0.35).

Conclusion:

EVAR presents a better short term outcome than OR in all classes of physiologic risk. In order to train future vascular surgeons on OR, only young and healthy patients, who carry a very low risk of adverse events, should be selected, aiming at the long term durability of the procedure.

Physiologic component of the estimation of physiologic ability and surgical stress scoring system as a predictor of immediate outcome after elective open abdominal aortic aneurysm repair

BACKGROUND

Previous studies have shown a good predictive power of the risk scoring method, Estimation of Physiologic Ability and Surgical Stress, in predicting mortality after open elective aortic aneurysm repair. The aim of the present study was to evaluate the physiologic component of this method to assess mortality risk in a different geographic population from previously published reports.

METHODS

Operative, morbidity and mortality data were collected retrospectively from charts of patients submitted to elective open repair of an abdominal aortic aneurysm over an 8-year period. There were 214 patients, the median age was 70 (range: 48-91) years; 179 (83.6%) patients were men. The Preoperative Physiologic Risk Score (PRS), Surgical Stress Score, and Comprehensive Risk Score (CRS) values were categorized and compared with morbidity and mortality rates.

RESULTS

There were 27 deaths (12.6%), and 81 (37.9%) patients experienced a postoperative complication that required medical intervention. There was a significant statistical difference for the values of PRS and CRS for patients who survived (0.53/0.63, respectively) and for those who died (0.88/1.02, respectively), p < 0.0001 for both values. There is a strong correlation between PRS and CRS values and development of complications (p < 0.0001). Surgical Stress Score did not correlate as strongly to development of complications (p = 0.0028). For PRS, the area under the receiver-operator characteristic curve was 0.844 (95% confidence interval: 0.747-0.941) for mortality and 0.725 (95% confidence interval: 0.650-0.799) for morbidity. For CRS, the area under the curve was 0.812 (95% confidence interval: 0.734-0.891) for mortality and 0.719 (95% confidence interval: 0.645-0.792) for morbidity. There was also a significant positive correlation between length of hospital stay and PRS and CRS scores (p < 0.0001). In this study, it was found that renal impairment has a significant positive correlation with mortality (p = 0.0008), with an odds ratio of 4.3. In a multivariate regression analysis, renal impairment failed to increase the accuracy of the model when associated with the other parameters considered in PRS.

CONCLUSION

This study corroborates with the previous findings that the Estimation of Physiologic Ability and Surgical Stress model seems to be a promising method of predicting death and postoperative complications in patients undergoing open abdominal aortic aneurysm repair.

Objective risk-scoring systems for repair of abdominal aortic aneurysms: applicability in endovascular repair?

OBJECTIVES

Recent studies propose the use of objective risk-scoring systems as a clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair (EVR). The aim of this study was to evaluate four established risk-scoring systems for accuracy of prediction of early mortality and morbidity following EVR.

PATIENTS AND METHODS

266 consecutive patients undergoing elective EVR at St. George's Vascular Institute between July 2001 and January 2007 were studied using a prospective database. The Glasgow Aneurysm Score (GAS), the Vascular Physiology and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM), the modified Customised Probability Index (m-CPI) and the Customised Probability Index (CPI) were applied for prediction of 30-day mortality and morbidity. Accuracy of prediction was compared using receiver operating characteristics (ROC) curve analyses.

RESULTS

30-day mortality and morbidity rates were 4% (11/266) and 8% (22/266) respectively. For prediction of mortality, GAS, V-POSSUM, m-CPI and CPI ROC curve analyses showed areas under the curves (AUCs) of 0.68 (95% confidence interval (CI), 0.48-0.87; p=0.046), 0.66 (95% CI, 0.51-0.81; p=0.067), 0.63 (95% CI, 0.45-0.81; p=0.148) and 0.65 (95% CI, 0.49-0.80; p=0.101) respectively. Corresponding AUCs for prediction of morbidity were 0.64 (95% CI, 0.51-0.76; p=0.511), 0.62 (95% CI, 0.51-0.74; p=0.505), 0.54 (95% CI, 0.41-0.67; p=0.416) and 0.55 (95% CI, 0.42-0.68; p=0.451).

CONCLUSIONS

GAS, V-POSSUM, m-CPI and CPI were poor predictors of early mortality and morbidity following EVR in this series. Caution should be applied to the use of these scoring systems for pre-operative risk stratification and treatment selection for endovascular repair of abdominal aneurysms.