Early mortality of surgically treated ruptured abdominal aortic aneurysms (rAAAs) still remains as high as 70%. In the current Literature, some studies have identified predictive models in order to evaluate 30-day outcomes of rAAAs. All these models included preoperative clinical status and laboratory parameters. Another factor to be taken into account is the surgical volume of the center. The aim of the study was to evaluate pre- and intraoperative factors affecting early outcomes in patients underwent OSR for rAAA in a high-volume tertiary referral center with the proposal of a prediction model for 30-day mortality.

Between January 2007 and December 2020 265 patients with certain diagnosis of rAAA detected at computed tomography (CT) angiography were admitted to our Emergency Department of a tertiary referral hospital. Twenty-three patients died before surgery due to haemodynamic shock and/or cardiac arrest. In addition, 10 patients received endovascular repair and they have been excluded from the present series. Therefore, the study population included 222 patients who underwent OSR. Pre- and intra-operative factors were analyzed by means of univariate analysis (step 1). Associations of patient and procedure variables with 30-day mortality rates were sought based on a multivariate Cox regression analysis (step 2). A mortality probability index was created by using a linear combination of all predictive factors multiplied by coefficients of the multiple logistic regression.

Median Intensive Care Unit (ICU) stay was 3 days (IQR 2-6). Five patients (2.2%) underwent redo surgery (2 bleeding, and 3 bowel ischemia). Perioperative complications were: MACE in 24 cases (10.8%), and respiratory in 10 cases (4.5%). MOF occurred in 21 cases (9.4%). Overall, 30-day mortality rate was 28.8 % (64 cases). Multivariate Cox regression analysis reported that age at intervention (>80 years), hypertension, congestive heart failure, chronic obstructive pulmonary disease, resuscitation maneuvers before surgery, loss of consciousness, and operation time >240 minutes were negative predictive factors for 30-day mortality risk. Patency of at least one hypogastric artery and infrarenal clamping had a protective role in reducing 30-day mortality rate (Table 1). For calculating the mortality index, the equation used is: index = 0.0639796 x age at intervention + 0.7711418 x COPD + 1.697474 x CHF + 1.210601 x hypertension + 1.767098 x resuscitation maneuvers + -1.123822 x loss of consciousness + 0.9932287 x nasogastric tube + 0.0060033 x operation time + -3.054342 x hypogastric artery reimplantation + -1.444247 x suprarenal clamping + -1.552103 x infrarenal clamping. Mortality index showed that a unitary increased is associated with an increased risk of mortality of 13%. A cut off point of 67.5 was found with a sensitivity of 81%, specificity of 78%, positive predictive value of 59%, and negative predictive value of 92%. Patients with values less than 67.5 had a 30-day mortality risk of 8.8%, whilst patient with values over 67.5 had a risk of 60.4%.

Elderly age, hypertension, congestive heart failure, chronic obstructive pulmonary disease, resuscitation maneuvers before surgery, loss of consciousness, and operation time >240 minutes affected 30-day mortality in patients undergoing OSR for rAAA. Patency of at least one hypogastric artery and infrarenal clamping had a protective role. In our mortality probability index a value over 67.5 increased the 30-day mortality risk up to 60%. An app could be useful to calculate the prediction mortality index and to facilitate the communication with the patients and their families.

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