Preoperative risk score accuracy confirmed in a modern ruptured abdominal aortic aneurysm experience

      Abstract

      Objective

      Various risk score calculators used to predict 30-day mortality after treatment of ruptured abdominal aortic aneurysms (rAAAs) have produced mixed results regarding their usefulness and reproducibility. We prospectively validated the accuracy of our preoperative scoring system in a modern cohort of patients with rAAAs.

      Methods

      A retrospective review of all patients wiith rAAAs who had presented to a single academic center from January 2002 to December 2018 was performed. The patients were divided into three cohorts according to when the institutional practice changes had occurred: the pre-endovascular aneurysm repair (EVAR) era (January 2002 to July 2007), the pre-Harbor View risk score era (August 2007 to October 2013), and the modern era (November 2013 to December 2018). The primary outcome measure was 30-day mortality. Our preoperative risk score assigns 1 point for each of the following: age >76 years, pH <7.2, creatinine >2 mg/dL, and any episode of hypotension (systolic blood pressure <70 mm Hg). The previously reported mortality from a retrospective analysis of the first two cohorts was 22% for 1 point, 69% for 2 points, 78% for 3 points, and 100% for 4 points. The goal of the present study was to prospectively validate the Harborview scoring system in the modern era.

      Results

      During the 17-year study period, 417 patients with rAAAs were treated at our institution. Of the 118 patients treated in the modern era, 45 (38.1%) had undergone open aneurysm repair (OAR), 61 (51.7%) had undergone EVAR, and 12 (10.2%) had received comfort measures only. Excluding the 12 patients without aneurysm repair, we found a statistically significant linear trend between the preoperative risk score and subsequent 30-day mortality for all patients combined (P < .0001), for OAR patients alone (P = .0003), and for EVAR patients alone (P < .0001). After adjustment for the Harborview risk score, the 30-day mortality was 41.3% vs 31.6% after OAR vs EVAR, respectively (P = .2). For all repairs, the 30-day mortality was 14.6% for a score of 0, 35.7% for a score of 1, 68.4% for a score of 2, and 100% for a score of 3 or 4.

      Conclusions

      Our results, representing one of the largest modern series of rAAAs treated at a single institution, have confirmed the accuracy of a simple 4-point preoperative risk score in predicting 30-day mortality in the modern rAAA patient. Such tools should be used when discussing the treatment options with referring physicians, patients, and their family members to help guide transfer and treatment decision-making.

      Graphical abstract

      Keywords

      Article Highlights
      • Type of Research: A single-center, prospective cohort study
      • Key Findings: Among a modern cohort of 118 patients with ruptured abdominal aortic aneurysms, the Harborview risk score, which assigns 1 point for each of four preoperative variables when present (age >76 years; pH <7.2; creatinine >2 mg/dL, and any episode of hypotension, defined as systolic blood pressure <70 mm Hg), was associated with 30-day mortality of 14.6% for a score of 0, 35.7% for a score of 1, 68.4% for a score of 2, and 100% for a score of 3 or 4.
      • Take Home Message: The Harborview risk score, a 4-point preoperative risk scoring tool, accurately predicted 30-day mortality after treatment of ruptured abdominal aortic aneurysms.
      CME Activity
      Purpose or Statement of Need The purpose of this journal-based CME activity is to enhance the vascular specialist’s ability to diagnose and care for patients with the entire spectrum of circulatory disease through a comprehensive review of contemporary vascular surgical and endovascular literature.
      Learning Objective
      • Predict, prior to treatment, the likelihood of 30-day survival after either open or endovascular repair of a ruptured AAA.
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      Ruptured abdominal aortic aneurysms (rAAAs) represent a challenging surgical emergency with high mortality rates despite repair.
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      Although centralization of care and the adoption of endovascular aneurysm repair (EVAR) treatment strategies have improved survival after rAAA repair, the treatment of rAAAs is resource intensive, and mortality has remained high.
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      Five-year survival following endovascular repair of ruptured abdominal aortic aneurysms is improving.
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      In patients stratified by preoperative risk, endovascular repair of ruptured abdominal aortic aneurysms has a lower in-hospital mortality and morbidity than open repair.
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      Outcomes after ruptured abdominal aortic aneurysm repair in the era of centralized care.
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      Assessing trends, morbidity, and mortality in ruptured abdominal aortic aneurysm repair with 9 years of data from the National Surgical Quality Improvement Program.
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      Endovascular repair of ruptured abdominal aortic aneurysm is superior to open repair: propensity-matched analysis in the Vascular Quality Initiative.
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      Endovascular repair of ruptured abdominal aortic aneurysms: a systematic review and meta-analysis.
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      Ruptured abdominal aortic aneurysms: endovascular repair versus open surgery—systematic review.
      The existence of an accurate preoperative risk stratification tool, which could predict who might benefit from surgery, would, therefore, not only help guide clinicians and patients in decision-making, but would also allow for the appropriate allocation of healthcare resources.
      Previous work at our institution developed the Harborview risk score (HRS), a simple risk scoring tool that uses four preoperative factors to estimate 30-day mortality: age, pH, creatinine, and hypotension.
      • Garland B.T.
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      • Desikan S.
      • Tran N.T.
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      • Singh N.
      • et al.
      Preoperative risk score for the prediction of mortality after repair of ruptured abdominal aortic aneurysms.
      Although various risk score calculators are available to predict 30-day mortality after treatment of rAAAs, they have produced mixed results regarding their usefulness and reproducibility.
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      • Murie J.
      • Chalmers R.
      Predictors of outcome after abdominal aortic aneurysm rupture: Edinburgh ruptured aneurysm score.
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      • Schreve M.A.
      • Ünlü Ç.
      Evaluation of five different aneurysm scoring systems to predict mortality in ruptured abdominal aortic aneurysm patients.
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      • AtanasovG
      • et al.
      Risk stratification of ruptured abdominal aortic aneurysms in patients treated by open surgical repair.
      • Robinson W.P.
      • Schanzer A.
      • Li Y.
      • Goodney P.P.
      • Nolan B.W.
      • Eslami M.H.
      • et al.
      Derivation and validation of a practical risk score for prediction of mortality after open repair of ruptured abdominal aortic aneurysms in a U.S. regional cohort and comparison to existing scoring systems.
      • Thompson P.C.
      • Dalman R.L.
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      • Chandra V.
      • Lee J.T.
      • Mell M.W.
      Predictive models for mortality after ruptured aortic aneurysm repair do not predict futility and are not useful for clinical decision making.
      The primary aim of the present study was to prospectively validate the accuracy of the HRS in a modern cohort of patients with rAAAs. We hypothesized that, despite advancements in endovascular technology, and the increased usage of EVAR in rAAA treatment, the HRS would accurately predict 30-day mortality.

      Methods

      A single-center, retrospective review of a prospectively collected rAAA database analyzing all consecutive patients who had presented with a rAAA to Harborview Medical Center from January 2002 to December 2018 was performed. Harborview Medical Center acts as the only quaternary referral center serving Alaska, Washington, Idaho, Montana, and Wyoming and, thus, receives transfers from throughout this five-state region. The database in use at our institution has been previously described.
      • Garland B.T.
      • Danaher P.J.
      • Desikan S.
      • Tran N.T.
      • Quiroga E.
      • Singh N.
      • et al.
      Preoperative risk score for the prediction of mortality after repair of ruptured abdominal aortic aneurysms.
      Data were abstracted for every patient using a direct review of the electronic medical records. The baseline demographics recorded included comorbid conditions, medications, age, and zip code. The prehospital data included the time of presentation to a referring facility, vital signs on arrival, and laboratory study results. The transfer details included the mode and time of transportation. The clinical status data on arrival to Harborview Medical Center included the initial laboratory values, vital signs, and whether resuscitation had been required before entering the operating room. The preoperative imaging findings and anatomic details included the maximum AAA size, neck length, neck angulation, and neck diameter. The anesthesia records included the use of intraoperative resuscitation, heparin dosing, and intraoperative vital signs. The operative course details included the repair type, procedure length, estimated blood loss, total contrast usage, fluoroscopy time, and the use of an aortic occlusion balloon. Finally, the postoperative outcomes included mortality, complications, and discharge disposition. Data abstraction was performed by five attending surgeons and three residents. The University of Washington institutional review board approved the present study and waived the requirement for patient written informed consent.
      The patients were divided into three cohorts according to when the institutional practice changes had occurred: the pre-EVAR era (January 2002 to July 2007), during which nearly all repairs were open aneurysm repairs (OARs); the pre-HRS era (August 2007 to October 2013), during which an EVAR-first treatment algorithm was used but preoperative risk score calculators to estimate patient mortality and guide treatment decision-making were not available; and the modern era (November 2013 to December 2018). The HRS, which assigns 1 point each for age >76 years, preoperative pH <7.2, creatinine >2 mg/dL, and any episode of hypotension (systolic blood pressure <70 mm Hg), was created from a retrospective analysis of the first two cohorts, with reported mortality of 22% for 1 point, 69% for 2 points, 78% for 3 points, and 100% for 4 points.
      • Garland B.T.
      • Danaher P.J.
      • Desikan S.
      • Tran N.T.
      • Quiroga E.
      • Singh N.
      • et al.
      Preoperative risk score for the prediction of mortality after repair of ruptured abdominal aortic aneurysms.
      The primary outcome measure in the present study was 30-day mortality in the modern cohort, with the aim of prospectively evaluating the accuracy of the HRS in the modern cohort.
      Statistical analysis was performed using Stata, version 14.1, software (StataCorp LP, College Station, Tex). Univariate and multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) for 30-day death and evaluate the potential association between 30-day mortality after rAAA repair and multiple potential predictor variables, including the HRS, repair type (OAR vs EVAR), and cohort, among others. The strength of the association between the HRS and 30-day mortality after repair was evaluated in the third (modern) cohort and compared with the first and second (development) cohorts using the linear test for trend derived from the logistic regression analysis using both stratification and regression analyses to control for potential confounding factors. The performance of the HRS in the modern cohort was also evaluated graphically using receiver operating characteristic (ROC) curves. This association was compared with that seen in the first two cohorts, the sample from which the HRS was developed. The goodness of fit of the models predicting for 30-day mortality using the HRS was assessed using the area under the ROC curve (C-statistic).

      Results

      During the 17-year study period, 417 patients with rAAAs had been treated at our institution, with 391 (93.8%) undergoing surgery. The number of patients who had received comfort measures only were as follows: 3 of 136 (2.2%) in the first cohort, 11 of 163 (6.7%) in the second cohort, and 12 of 118 (10.2%) in the third cohort. This trend of an increasing proportion of patients treated with comfort measures only within each cohort was statistically significant (P = .01).
      The demographic, clinical, and anatomic characteristics of the 391 patients who had undergone OAR or EVAR (all three cohorts combined) are listed in Table I. Most patients were men (80.5%), with an average age of 74 years and an average AAA diameter of 83.2 mm. The HRS can have five discrete values, ranging from 0 to 4. A strong majority (88.5%) of the population had had an HRS ranging from 0 to 2, with 10% having an HRS of 3 and 1.5% an HRS of 4. Of the 391 patients, 240 had undergone OAR (61.4%) and 151 had undergone EVAR (38.6%).
      Table IPatient characteristics (n = 391 attempted repairs)
      CharacteristicTotal patients, No.Mean ± SD or No. (%)
      Demographic data
       Age, years38874.0 ± 8.7
       Male gender390314 (80.5)
      HRS3911.25 ± 1.01
       0104 (26.6)
       1138 (35.3)
       2104 (26.6)
       339 (10.0)
       46 (1.5)
      HRS components391
       Age >76 years163 (41.7)
       Creatinine >2.0 mg/dL72 (18.4)
       pH <7.20103 (26.3)
       SBP <70 mm Hg149 (38.1)
      Repair type391
       OAR240 (61.4)
       EVAR151 (38.6)
      Cohort391
       1133 (34.0)
       2152 (38.9)
       3106 (27.1)
      Other variables
       Heart rate >110 bpm39174 (18.9)
       Temperature <35°C360141 (39.2)
       Warfarin use36243 (11.9)
       INR >1.837474 (19.8)
       AAA diameter, mm32383.2 ± 21.4
       Transport by helicopter388197 (50.8)
      AAA, Abdominal aortic aneurysm; EVAR, endovascular aneurysm repair; HRS, Harborview risk score; INR, international normalized ratio; OAR, open aneurysm repair; SBP, systolic blood pressure; SD, standard deviation.
      The results of the univariate analysis of the association between 30-day mortality and multiple potential risk factors within the combined population (all three cohorts; n = 391) are presented in Table II. Several notable significant associations were found. The HRS and each of its components (age, preoperative serum creatinine concentration, pH, and lowest preoperative systolic blood pressure) were significantly associated with 30-day mortality after rAAA repair. For the patients with an HRS of 0, the risk of 30-day death after repair was 21.2%, with a continuous steadily increasing risk of 30-day mortality (average OR, 2.7; 95% confidence interval [CI], 2.1-3.5; P < .0001) per unit increase in the HRS (Fig 1). The risk of perioperative death for patients with an HRS of 4 was 100% (six of six patients; 95 CI, 62%-100%). The repair type also had a strong association with the risk of 30-day mortality after repair. The perioperative (30-day) mortality after OAR was 52.9% (127 of 240 patients) compared with 28.5% (43 of 151 patients) after EVAR (P < .0001). The cohort also showed a noteworthy association with 30-day mortality after repair. A statistically significant (P = .0001) reduction was found in perioperative mortality between cohorts 1 (58.7%) and 2 (35.5%), with no significant change between cohorts 2 and 3 (35.9%). Other variables with statistically significant univariate associations with 30-day mortality after repair included a preoperative heart rate >110 bpm, preoperative temperature <35°C, preoperative warfarin use, and preoperative international normalized ratio (INR) >1.8.
      Table IIUnivariate analysis of correlates of 30-day mortality among repaired rAAA patients (n = 391)
      FactorPatients, No.30-Day Mortality, %OR (95% CI)P value
      Gender1.0 (0.6-1.7)1.0
       Female7643.4
       Male31443.6
      HRS by category
       Overall<.0001
       010421.2
       113832.61.8 (1.0, 3.3).05
       210662.56.2 (3.4, 11.5)<.0001
       33982.117.0 (6.6-43.8)<.0001
       46100.0InfiniteNA
      HRS per unit increase3912.7 (2.1-3.5)<.0001
      HRS components
       Age, years2.5 (1.6-3.8)<.0001
      ≤7622834.2
      >7616356.4
       Creatinine, mg/dL2.2 (1.4-3.8).002
      ≤2.031939.8
      >2.07259.7
       pH3.5 (2.2-5.7)<.0001
      ≥7.228835.4
      <7.210366.0
       SBP, mm Hg3.4 (2.2-5.2)<.0001
      ≥7024232.2
      <7014961.7
      Repair type2.8 (1.8-4.4).0004
       EVAR15128.5
       OAR24052.9
      Cohort by category
       Overall.0001
       113358.72.5 (1.5-4.3).01
       215235.51.0 (0.6-1.7)1.0
       310635.9
      Other variables
       Heart rate, bpm2.8 (1.8-4.4)<.0001
      ≤11031738.5
      >1107464.9
       Temperature, °C1.8 (1.1-2.7).01
      ≥3521937.9
      <3514151.8
       Warfarin use2.2 (1.1-4.2).02
      No31938.9
      Yes4358.1
       INR3.3 (2.0-5.7)<.0001
      ≤1.830037.0
      >1.87466.2
       Helicopter transport0.8 (0.6-1.2).4
      No19145.6
      Yes19741.1
      CI, Confidence interval; EVAR, endovascular aneurysm repair; HRS, Harborview risk score; INR, international normalized ratio; NA, not applicable; OAR, open aneurysm repair; OR, odds ratio; rAAA, ruptured abdominal aortic aneurysm; SBP, systolic blood pressure.
      Figure thumbnail gr1
      Fig 1Relationship between Harborview risk score (HRS) and 30-day mortality after repair. The blue bars represent the observed 30-day mortality stratified by the HRS (error bars indicate 95% confidence intervals [CIs]), with the red line representing the predicted probabilities treating HRS as a continuous variable in the logistic regression analysis. The odds ratio (OR) of 30-day death increased an average of 2.7-fold per unit increase in the HRS.
      All the factors associated (P < .1) with 30-day mortality on univariate analysis were entered into a backward stepwise multivariate logistic regression model. The following variables were retained in the model with a threshold P value of <.05: HRS, repair type, INR >1.8, and heart rate >110 bpm (Table III). After adjustment for repair type, the cohort effect (reduction in 30-day mortality between cohorts 1 and 2) was substantially reduced and no longer statistically significant, with the residual effect accounted for by a reduction in mortality within the OAR group. The multivariate analysis confirmed a strong association (OR, 2.5 per unit increase in the HRS; 95% CI, 1.9-3.3; P < .0001) between the HRS and 30-day mortality, even after adjustment for other statistically significant correlates of 30-day mortality in our dataset.
      Table IIIMultivariate analysis of factors associated with 30-day mortality after attempted rAAA repair
      VariablesOR (95% CI)P value
      HRS (per unit increase)2.5 (1.9-3.3)<.0001
      Repair type (OAR vs EVAR)3.1 (1.8-5.1)<.0001
      INR (>1.8 vs ≤1.8)2.9 (1.6-5.3).0007
      Heart rate (>110 vs ≤110 bpm)1.9 (1.0-3.5).049
      CI, Confidence interval; EVAR, endovascular aneurysm repair; HRS, Harborview risk score; INR, international normalized ratio; OAR, open aneurysm repair; rAAA, ruptured abdominal aortic aneurysm.
      The validity of the HRS in the third (modern) cohort was then evaluated and compared with the study population from which the HRS had been originally developed (the combined first and second cohorts). The distribution of 30-day mortality, stratified by the HRS and repair type, among the development and modern cohorts is presented in Tables IV and V, respectively. In the development cohorts (Table IV), the average OR for 30-day mortality was 2.5 (95% CI, 1.9-3.4) per unit increase in the HRS (P < .0001). In the modern cohort (Table V), the average OR for 30-day mortality was 4.0 (95% CI 2.1, 7.4) per unit increase in the HRS (P = .0001) for both repair types combined. No evidence was found for a statistically significant difference in the strength of the association between the HRS and 30-day mortality between the two repair types (P for interaction = .3) or the two cohort groups (P for interaction = .2). The relationship between the HRS and 30-day mortality (both repair types combined) is shown graphically in Fig 2, A, for the development cohorts and Fig 2, B, for the modern cohort.
      Table IVThirty-day mortality stratified by repair type and risk score in development cohorts
      VariableCombined mortalityOAR mortalityEVAR mortality
      All132/285 (46.3)109/195 (55.9)23/90 (25.6)
      HRS
       016/63 (25.4)10/43 (23.3)6/20 (30.0)
       130/96 (31.3)27/59 (45.8)3/37 (8.1)
       252/85 (61.2)43/60 (71.7)9/25 (36.0)
       329/36 (80.6)24/28 (85.7)5/8 (62.5)
       45/5 (100)5/5 (100)0/0 (0)
      OR per HRS (95% CI)2.5 (1.9-3.4)2.9 (2.0-4.1)1.7 (1.0-3.0)
      P value for trend<.0001<.0001.04
      CI, Confidence interval; EVAR, endovascular aneurysm repair; HRS, Harborview risk score; OAR, open aneurysm repair; OR, odds ratio.
      Data presented as number/total (%).
      Table VThirty-day mortality stratified by repair type and risk score in modern cohort
      VariableCombined mortalityOAR mortalityEVAR mortality
      All38/106 (35.8)18/45 (40.0)20/61 (32.8)
      HRS
       06/41 (14.6)2/17 (11.8)4/24 (16.7)
       115/42 (35.7)11/20 (55.0)4/22 (18.2)
       213/19 (68.4)4/7 (57.1)9/12 (75.0)
       33/3 (100)1/1 (100)2/2 (100)
       41/1 (100)0/0 (0)1/1 (100)
      OR per HRS (95% CI)4.0 (2.1-7.4)3.7 (1.4-9.7)4.2 (1.9-9.5)
      P value for trend.0001.009.0006
      CI, Confidence interval; EVAR, endovascular aneurysm repair; HRS, Harborview risk score; OAR, open aneurysm repair; OR, odds ratio.
      Data presented as number/total (%).
      Figure thumbnail gr2
      Fig 2Relationship between Harborview risk score (HRS) and 30-day mortality after repair for the development cohorts (n = 285; A) and modern cohort (n = 106; B). The blue bars represent observed 30-day mortality stratified by the HRS (error bars indicate 95% confidence intervals [CIs]), with the red lines representing the predicted probabilities treating HRS as a continuous variable in the logistic regression analysis. The odds ratio (OR) of 30-day mortality increased an average of 2.5-fold per unit increase in the HRS in the development cohorts and 4.0-fold in the modern cohort.
      The numbers of 30-day deaths and 30-day survivors stratified by the HRS and the cohort for both repair types are shown in Fig 3. The ability of the HRS to predict for 30-day mortality was evaluated using ROC curves (Fig 4). In these ROC curves, both repair types were combined. In the development cohorts, the area under the ROC curve was 0.7234 (95% CI, 0.6664-0.7805). In the modern cohort, the area under the ROC curve was remarkably similar at 0.7545 (95% CI, 0.6624-0.8465). The difference between these two areas was not statistically significant (P = .6).
      Figure thumbnail gr3
      Fig 3Distribution of 30-day mortality stratified by Harborview risk score (HRS) in the development cohorts vs the modern cohort.
      Figure thumbnail gr4
      Fig 4Receiver operating characteristics (ROC) curves evaluating the prediction of 30-day mortality stratified by the Harborview risk score (HRS) in the development cohorts (blue line) vs the modern cohort (red line). The area under the curve for the development and modern cohorts was 0.7234 and 0.7545, respectively. The difference between these two areas was not statistically significant (P = .6).
      For the 26 patients treated with comfort measures only during the study period, the distribution of the HRS was approximately normal without a clear bias toward higher scores (Fig 5). Of the 26 patients, 16 had had scores ranging from 0 to 2 and 10 had had a score of 3 or 4. The decision to pursue comfort measures was made by patients, or their surrogate decision makers, after discussions with the treating surgeon, and were not determined by surgeon application of the HRS to determine futility.
      Figure thumbnail gr5
      Fig 5Distribution of Harborview risk scores (HRSs) for 26 patients treated with comfort measures only.

      Discussion

      To the best of our knowledge, the present study represents one of the largest single-institution experiences with rAAA, including 417 patients treated during a 17-year study period, and demonstrates the changing trends and outcomes seen with institutional changes in practice over time. After the institution of an EVAR-first approach, the overall mortality had decreased from 59% to 35%, improvements resulting from both the increased adoption of endovascular techniques and improvements in mortality after OAR. These results are similar to previously reported Vascular Quality Initiative, National Surgical Quality Improvement Program, and multicenter studies demonstrating improved short- and mid-term outcomes with EVAR compared with OAR, contributing further to the increasing body of data supporting an EVAR-first approach for patients with suitable anatomy.
      • Oliveira-Pinto J.
      • Soares-Ferreira R.
      • Oliveira N.F.G.
      • Bastos Gonçalves F.M.
      • Hoeks S.
      • Van Rijn M.J.
      • et al.
      Comparison of midterm results of endovascular aneurysm repair for ruptured and elective abdominal aortic aneurysms.
      ,
      • D’Oria M.
      • Hanson K.T.
      • Shermerhorn M.
      • Bower T.C.
      • Mendes B.C.
      • Shuja F.
      • et al.
      Editor’s choice – short term and long term outcomes after endovascular or open repair for ruptured infrarenal abdominal aortic aneurysms in the Vascular Quality Initiative.
      ,
      • Van Beek S.C.
      • Conijn A.P.
      • Koelemay M.J.
      • Balm R.
      Endovascular aneurysm repair versus open repair for patients with a ruptured abdominal aortic aneurysm: a systematic review and meta-analysis of short-term survival.
      • Varkevisser R.R.B.
      • Swerdlow N.J.
      • de Guerre L.E.V.M.
      • Dansey K.
      • Stangenberg L.
      • Giles K.A.
      • et al.
      Five-year survival following endovascular repair of ruptured abdominal aortic aneurysms is improving.
      • Ali M.M.
      • Flahive J.
      • Schanzer A.
      • Simons J.P.
      • Aiello F.A.
      • Doucet D.R.
      • et al.
      In patients stratified by preoperative risk, endovascular repair of ruptured abdominal aortic aneurysms has a lower in-hospital mortality and morbidity than open repair.
      ,
      • Wang L.J.
      • Locham S.
      • Eagleton M.J.
      • Clouse W.D.
      • Malas M.
      Endovascular repair of ruptured abdominal aortic aneurysm is superior to open repair: propensity-matched analysis in the Vascular Quality Initiative.
      ,
      • Salata K.
      • Hussain M.A.
      • de Mestral C.
      • Greco E.
      • Awartani H.
      • Aljabri B.A.
      • et al.
      Population-based long-term outcomes of open versus endovascular aortic repair of ruptured abdominal aortic aneurysms.
      ,
      • Starnes B.W.
      • Quiroga E.
      • Hutter C.
      • Tran N.T.
      • Hatsukami T.
      • Meissner M.
      • et al.
      Management of ruptured abdominal aortic aneurysm in the endovascular era.
      More importantly, our results have confirmed the validity of the HRS in predicting for 30-day mortality in a prospective consecutive series of modern patients with rAAAs. These results are similar to our previously reported results and have confirmed that the presence of four preoperative factors is associated with a very high risk of 30-day death after repair. Although the validity of various risk scoring systems, including the HRS, has been previously confirmed by other groups, those studies were been limited by small sample sizes, evaluating <50 patients each.
      • Ciaramella M.A.
      • Ventarola D.
      • Ady J.
      • Rahimi S.
      • Beckerman W.E.
      Modern mortality risk stratification scores accurately and equally predict real-world postoperative mortality after ruptured abdominal aortic aneurysm.
      ,
      • Hansen S.K.
      • Danaher P.J.
      • Starnes B.W.
      • Hollis H.W.
      • Garland B.T.
      Accuracy evaluations of three ruptured abdominal aortic aneurysm mortality risk scores using an independent dataset.
      The present study, with 106 rAAA patients treated within a 5-year span, adds to the existing data by doubling the number of patients evaluated.
      Although risk scores should never be used alone, without consideration of other potential factors that could influence a patient's short- and long-term prognosis, they can provide vitally important information that can help guide clinical decision-making before treatment or transfer of the patient between hospitals. Given the highly morbid and resource-intensive nature of rAAA repair, risk stratification tools are important adjuncts that can guide patients, families, and clinicians through challenging decisions. Among these, the HRS is unique in that it is extremely simple, relying on four pieces of information readily available to the vascular surgeon, and yet remains very accurate, with a strong demonstrated correlation with the risk of perioperative death in a large retrospective study and confirmed in the present large prospective study.
      • Garland B.T.
      • Danaher P.J.
      • Desikan S.
      • Tran N.T.
      • Quiroga E.
      • Singh N.
      • et al.
      Preoperative risk score for the prediction of mortality after repair of ruptured abdominal aortic aneurysms.
      Our study had potential limitations. First, given the single-center nature of our study, it is possible that our risk scoring system might not be generalizable to other institutions. However, although the Harborview Medical Center is a quaternary referral center serving a broad geographic area, with transit times for rAAA patients, thus, being quite long, it is unlikely these factors would alter the validity of the HRS. Instead, the HRS could function as a stratification tool that adjusts for these differences, allowing for a more equal comparison of patient subgroups with similar levels of hemodynamic challenges across institutions. Second, although the overall numbers of rAAA patients were quite large, the number of patients within the high-risk groups (HRS of 3 and 4) was relatively small. Therefore, the results from the present study do not allow us to conclude with 100% certainty that a patient with a HRS of 4 has no chance to survive repair. This issue has been addressed in a previous single-center study, in which one of two patients with a HRS of 4 survived to 30 days after repair.
      • Thompson P.C.
      • Dalman R.L.
      • Harris E.J.
      • Chandra V.
      • Lee J.T.
      • Mell M.W.
      Predictive models for mortality after ruptured aortic aneurysm repair do not predict futility and are not useful for clinical decision making.
      Although that study highlighted that an HRS of 4 might not be associated with 100% 30-day mortality among patients treated at all institutions, it does not negate that a higher HRS was associated with high mortality and poor outcomes, an observation confirmed by other investigators.
      • Ciaramella M.A.
      • Ventarola D.
      • Ady J.
      • Rahimi S.
      • Beckerman W.E.
      Modern mortality risk stratification scores accurately and equally predict real-world postoperative mortality after ruptured abdominal aortic aneurysm.
      ,
      • Hansen S.K.
      • Danaher P.J.
      • Starnes B.W.
      • Hollis H.W.
      • Garland B.T.
      Accuracy evaluations of three ruptured abdominal aortic aneurysm mortality risk scores using an independent dataset.
      Use of the HRS allows for frank, honest discussions with patients and families when surgeons are providing preoperative counseling. However, the amount data at this time is not enough to support its use as a tool to determine futility with certainty.
      Although the results from the present study have confirmed the accuracy of the HRS, our study also raises interesting questions that require further investigation. During the 17-year study period, we saw improved mortality after rAAA repair that was partially explained by the adoption of EVAR but had also resulted from a reduction in mortality for patients treated with OAR, perhaps related to increasing surgeon experience. In our previous report, we noted 100% mortality in patients who were not EVAR candidates because of the proximal neck but who had undergone an EVAR attempt.
      • Starnes B.W.
      • Garland B.T.
      • Desikan S.
      • Tran N.T.
      • Quiroga E.
      • Singh N.
      VESS26. EVAR candidacy impacts 30-day mortality for REVAR but not for open repair of ruptured abdominal aortic aneurysms.
      In the present patient population, directly moving to OAR likely made a difference, because our institution performs a large volume of open aortic procedures. Other factors that could account for the overall improvement in mortality over time included the use of aortic occlusion balloons, improved perioperative resuscitation, and improved postoperative intensive care unit after following OAR. We did not see similar improvements in survival after EVAR over time, the reasons for which are not clear. Although previous studies have confirmed that hostile aneurysm anatomy is associated with worse outcomes after EVAR, the relative importance of these “hostile factors” and any changes in their prevalence over time has remained undefined.
      • Starnes B.W.
      • Garland B.T.
      • Desikan S.
      • Tran N.T.
      • Quiroga E.
      • Singh N.
      VESS26. EVAR candidacy impacts 30-day mortality for REVAR but not for open repair of ruptured abdominal aortic aneurysms.
      ,
      • Kontopodis N.
      • Tavlas E.
      • Ioannou C.V.
      • Giannoukas A.D.
      • Geroulakos G.
      • Antoniou G.A.
      Systematic review and meta-analysis of outcomes of open and endovascular repair of ruptured abdominal aortic aneurysm in patients with hostile vs. friendly aortic anatomy.
      Finally, we found that an elevated INR and heart rate (>110 bpm) were significantly associated with greater 30-day mortality after repair, even after adjustment for the HRS and surgical repair type. Potential modification of the HRS remains a topic of ongoing research.

      Conclusions

      The HRS, which uses a simple 4-point scale of preoperative factors, with 1 point each assigned for age >76 years, creatinine >2 mg/dL, pH <7.2, and any episode of systolic blood pressure <70 mm Hg, correlated strongly with 30-day mortality in modern rAAA patients. Accurate risk prediction tools, such as the HRS, should be used when discussing treatment options with patients and family members to help guide transfer and treatment decision-making.

      Author contributions

      Conception and design: JH, BF, TB, EQ, NT, NS, BS
      Analysis and interpretation: JH, BF, MC, EQ, NT, NS, BS
      Data collection: TB, EQ, NT, NS, BS
      Writing the article: JH, MC, BS
      Critical revision of the article: JH, BF, MC, TB, EQ, NT, NS, BS
      Final approval of the article: JH, BF, MC, TB, EQ, NT, NS, BS
      Statistical analysis: JH, MC
      Obtained funding: Not applicable
      Overall responsibility: BS

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