RU2833779C1 - Method for prediction of risk of developing acute renal injury after open reconstruction of abdominal aorta for aneurysm - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to cardiovascular surgery. In abdominal aorta prosthetics, blood loss is assessed in millilitres. Following factors are evaluated in points: renal artery clamping, blood loss, thrombectomy from the prosthesis or arteries of lower extremities, additional transfusion of erythrocyte suspension after operation. Points are summed up. If the total score is one point – low risk, two points – medium risk, three points and more – high risk.

EFFECT: method enables predicting the risk of developing acute renal injury accompanying open abdominal aorta reconstruction by evaluating a complex of the most significant factors.

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Description

The invention relates to medicine, namely to cardiovascular surgery. It can be used in cardiovascular surgery departments.

Surgical correction of abdominal aortic aneurysms (AAA) is currently the main method of treatment [1]. More than half of patients develop various complications after surgery. Acute kidney injury (AKI) is the most common complication in AAA replacement and accounts for 10-63% [2].

The development of AKI in the postoperative period is associated with a 4-9-fold increase in mortality [3]. With isolated AKI, mortality is 34% [4], and with the development of multiple organ failure - 85-95% [5].

Due to the high frequency of development of AKI during AAA replacement and the lack of reliable diagnostic criteria for this complication, it is necessary to develop a prognostic model that allows stratifying patients by risk level and predicting possible outcomes.

A model of the risk of developing AKI in patients after abdominal aortic reconstruction for aneurysm is known, which includes the following factors (the number of points is given in brackets if the patient has the factor): age over 75 years (1.5), symptomatic AAA (2), respiratory diseases (2), arterial hypertension (2), juxta- or suprarenal aneurysm (2), initial serum creatinine over 150 μmol/l (2.5) [6]. The disadvantage of the above model is the absence of intraoperative risk factors that have a significant impact on the pathogenesis of AKI development.

A calculator for the probability of developing AKI in patients over 80 years of age after AAA replacement is described: probability of developing AKI = e ^L /1+ e ^L *100%, where L= -5.56 + 1.26*Open surgery + 0.18*Female gender - 0.19*Hypertension + 0.69*Peripheral arterial atherosclerosis + 0.40*COPD + 0.29*Diabetes + 0.10*CKD2 + 0.78*CKD3+ 1.74*CKD4-5 - 0.43*ATT + 0.62*beta-blockers + 0.22*aneurysm diameter in cm [2]. The disadvantages of this calculator are the lack of intraoperative risk factors that have a significant impact on the pathogenesis of AKI development, as well as the possibility of using it only in patients over 80 years of age.

A prognostic model for the development of acute renal failure after AAA replacement has been proposed, including two factors: intraoperative hypotension (a decrease in mean arterial pressure to less than 60 mm Hg lasting more than 15 min) and a postoperative decrease in cardiac output [8]. Acute renal injury is a multifactorial pathology, and the lack of inclusion of such important factors as the volume of blood loss, the level of clamping, the amount of transfused blood, and the time of renal ischemia in this model is a significant drawback.

The ACEF scale for predicting the development of AKI was taken as a prototype of the proposed method, including the patient's age, preoperative creatinine level, and ejection fraction as risk factors. The formula for calculating the risk of developing AKI is presented as follows: age/ejection fraction + 1 (if the creatinine level is more than 2 mg/dl). This scale was validated on patients after endovascular aortic reconstruction [7]. The disadvantage of the given scale is the lack of intraoperative risk factors, as well as the possibility of using it only in patients who have undergone endovascular aortic replacement.

The aim of the invention is to introduce into clinical practice a method for predicting the risk of developing acute renal injury during open reconstruction of the abdominal aorta.

The proposed method is implemented as follows.

The retrospective study included 137 patients who were treated in the Faculty Surgery Clinic of the Samara State Medical University. All patients underwent planned abdominal aortic prosthetics. The patients were divided into two groups. The first group included patients (n=54) who developed acute renal injury in the postoperative period. The second group included patients (n=83) without renal dysfunction after surgery.

The following patient characteristics were analyzed: gender, age, smoking, comorbidities, body mass index, body surface area, glomerular filtration rate and preoperative creatinine level, aneurysm diameter, access type, reconstruction volume, renal artery clamping, left renal vein transection, lower limb artery reconstruction, renal artery interventions, mechanical ventilation, surgery time, blood loss, aortic clamping time, lower limb ischemia time, thrombectomy from the prosthesis or lower limb arteries, mean arterial pressure during surgery, blood component transfusion (red blood cell suspension, fresh frozen plasma), colloidal and crystalloid infusion, and diuresis volume.

To determine significant risk factors influencing the development of AKI after AAA replacement and to create a prognostic model, the binary logistic regression method was used.

The following results were obtained (Table 1).

Table 1. Significant risk factors influencing the development of AKI. No. Factor b p OSH 95% CI A1 Renal artery occlusion 1.66 0,016 6,904 1.43-33.69 A2 Blood loss, ml 0.003 <0.001 1,003 1.001-1.005 A3 Thrombectomy from prosthesis or arteries of the lower extremities 3.22 0.006 24.9 2.4-248.93 A4 Additional transfusion of red blood cell suspension after surgery 1.64 0.022 5.15 1.27-20.87 Constant -3,106 <0.001 OR - odds ratio, CI - confidence interval

The observed dependence is described by the equation:

P = 1/(1+e ^-z )*100%

Z = -3.106 + 1.66A ₁ + 1.5A ₂ + 3.22A ₃ + 1.64A ₄

Thus, the risk of acute renal injury during open AAA replacement increases with renal artery clamping by 6.9 times, for every 1 ml of blood loss by 1.003 times, with thrombectomy from the prosthesis and/or arteries of the lower extremities - by 24.9 times, with additional transfusion of red blood cell suspension after surgery - by 1.64 times. The specificity of this model is 88.9%, sensitivity - 69.8%. The significance of the model is p<0.001.

Based on the coefficients of each factor obtained in logistic regression, a risk scale for the development of AKI during open AAA replacement was formed. The blood loss coefficient was multiplied by 500 to calculate the risk of developing AKI for every 500 ml of bleeding. Then, to obtain points for each factor, all coefficients were divided by the minimum coefficient obtained in logistic regression. The final risk scale is presented in Table 2.

Table 2. Risk scale for the development of AKI with open AAA replacement No. Factor Availability b Points (b/1.5) A1 Renal artery occlusion Yes 1.66 1 No 0 0 A2 Blood loss, every 500 ml Yes 1.5 1 No 0 0 A3 Thrombectomy from prosthesis or arteries of the lower extremities Yes 3.22 2 No 0 0 A4 Additional transfusion of red blood cell suspension after surgery Yes 1.64 1 No 0 0

For each patient, the sum of points on this scale was calculated. Then, logistic regression was performed, in which the dependence of the development of AKI on the sum of points on the risk scale was estimated, obtaining predicted probabilities. These predicted probabilities were divided into quartiles to form risk groups. The first and second quartiles had the same value, so they were taken as one group (low risk). The third and fourth quartiles were taken as medium and high risk, respectively. Thus, the following risk groups were obtained:

1 point - low risk of developing acute kidney injury (18.2%).

2 points - average risk of developing acute kidney injury (25%).

3 points or more – high risk of developing acute kidney injury (56.8%).

This scale was validated. For this purpose, the average predicted probability of an event according to this scale was calculated, which was 34.6%. The average probability of the occurrence of AKI was 35.1%, which indicates the high validity of this scale.

The proposed method is implemented as follows:

1. The patient undergoes surgical intervention in the amount of abdominal aortic prosthetics.

2. After the operation, the points are calculated taking into account the following factors:

- Clamping of the renal arteries (Yes - one point, No - zero points);

- Every 500 ml of blood loss (one point);

- Thrombectomy from a prosthesis or arteries of the lower extremities (Yes - two points, No - zero points);

- Additional transfusion of red blood cell suspension after surgery (Yes - one point, No - zero points).

3. The sum of the points is used to determine the level of risk of developing acute kidney injury in the early postoperative period:

- One point - low risk (18.2%);

- Two points - average risk (25%);

- Three points or more – high risk (56.8%).

The advantages of the proposed method are:

1. Ease of use.

2. Possibility of use in both planned and emergency surgical interventions.

3. The possibility of starting preventive treatment of acute kidney injury before laboratory parameters change.

4. Does not require additional technical support and material costs.

LIST OF REFERENCES

1. Pokrovsky A.V. Diseases of the aorta and its branches / Pokrovsky A.V., Meditsina Publishing House, Moscow, 1979. 328 p.

2. Dang T, Dakour-Aridi H, Rizwan M, Nejim B, Malas MB. Predictors of acute kidney injury after infrarenal abdominal aortic aneurysm repair in octogenarians. J Vasc Surg. 2019. No. 3 (69). pp. 752-762.

3. Hicks CW, Black JH 3rd, Arhuidese I, Asanova L, Qazi U, Perler BA, Freischlag JA, Malas MB. Mortality variability after endovascular versus open abdominal aortic aneurysm repair in a large tertiary vascular center using a Medicare-derived risk prediction model. J Vasc Surg. 2015. No. 2 (61). pp. 291-297.

4. Studzińska D, Polok K, Chwała M, Zaczek M, Szczeklik W. The incidence of cardiovascular and other major complications after open abdominal aortic surgery. Kardiol Pol. 2023. No. 9 (81). pp. 870-877.

5. Kazanchyan P.O., Popov V.A. Complications in surgery of abdominal aortic aneurysms / Kazanchyan P.O., Popov V.A., Moscow: MEI Publishing House, 2002.

6. Grant SW, Grayson AD, Grant MJ, Purkayastha D, McCollum CN. What are the risk factors for renal failure following open elective abdominal aortic aneurysm repair? Eur J Vasc Endovasc Surg. No. 2 (43). pp. 182-187.

7. Avci Y, Demir AR, Güler A, Aktemur T, Bulut U, Demirci G, Memiç Sancar K, Ersoy B, Celik O, Erturk M. A simplified acute kidney injury predictor following endovascular aortic repair: ACEF score. Vascular. 2023. No. 1 (31). pp. 26-32.

8. Tallgren M, Niemi T, Pöyhiä R, Raininko E, Railo M, Salmenperä M, Lepäntalo M, Hynninen M. Acute renal injury and dysfunction following elective abdominal aortic surgery. Eur J Vasc Endovasc Surg. 2007. No. 5 (33). pp. 550-555.

Claims (1)

A method for predicting the risk of developing acute kidney injury after open reconstruction of the abdominal aorta due to aneurysm, characterized in that the patient undergoes surgical intervention in the volume of abdominal aortic prosthesis, blood loss is estimated in milliliters during the surgical intervention, after performing abdominal aortic prosthesis, the following factors are assessed in points: renal artery clamping: Yes - one point, No - zero points, every 500 ml of blood loss - one point, thrombectomy from the prosthesis or arteries of the lower extremities: Yes - two points, No - zero points, additional transfusion of red blood cell suspension after surgery: Yes - one point, No - zero points, the points are summed up and the risk of developing acute kidney injury in the early postoperative period is predicted based on the sum of the points obtained: one point - low risk, two points - medium risk, three points or more - high risk.