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Midterm Re-interventions and Survival After Endovascular Versus Open Repair for Ruptured Abdominal Aortic Aneurysm

Open ArchivePublished:April 01, 2015DOI:https://doi.org/10.1016/j.ejvs.2015.02.015

      Objective

      To compare the midterm re-intervention and survival rates after EVAR and OR for ruptured abdominal aortic aneurysms (RAAA).

      Methods

      Observational cohort study including all consecutive RAAA patients between 2004 and 2011 in 10 hospitals in the Amsterdam ambulance region. The primary end point was re-interventions within 5 years of the primary intervention. The secondary end point was death. The outcomes were estimated by survival analyses, compared using the logrank test, and subsequently adjusted for possible confounders using Cox proportional hazard models. Re-interventions were estimated in all patients and in patients who survived their hospital stay.

      Results

      Of 467 patients with a RAAA, 73 were treated by EVAR and 394 by OR. Five years after the primary intervention, the rates of freedom from re-intervention were 55% for EVAR (26/73, 95% CI: 41–69%) and 60% for OR (130/394, 95% CI: 55–66%) (p = .96). After adjustment for age, sex, comorbidity, and pre-operative hemodynamic stability, the risk of re-intervention was similar (HR 1.01, 95% CI: 0.65–1.55). The survival rates were 36% for EVAR (45/73, 95% CI: 24–47%) and 38% for OR (235/394, 95% CI: 33–43%) (p = .83). In 297 patients who survived their hospital stay, the rates of freedom from re-intervention were 66% for EVAR (15/54, 95% CI: 52–81%) and 90% for OR (20/243, 95% CI: 86–95%) (p < .01). After adjustment for age and sex, the risk of re-intervention was higher after EVAR (HR 0.27, 95% CI: 0.14–0.52).

      Conclusions

      Five years after the primary intervention, endovascular and open repair for ruptured abdominal aortic aneurysm resulted in similar re-intervention and survival rates. However, in patients who survived their hospital stay the re-intervention rate was higher for EVAR than for OR.

      Keywords

      Midterm outcomes are essential to the debate on whether endovascular (EVAR) or open repair (OR) is to be preferred for patients with a RAAA. This study showed that 5 years after the primary intervention, EVAR and OR resulted in similar re-intervention and survival rates. However, in patients who survived their hospital stay the re-intervention rate was higher for EVAR than for OR. When deciding between these interventions in the acute setting, caregivers have to balance short-term benefits after EVAR with the lower midterm risk of re-intervention after discharge for OR.

      Introduction

      Patients with a ruptured aneurysm of the abdominal aorta (RAAA) can be treated by endovascular (EVAR) or open repair (OR). To date, no significant difference in the 30 day mortality rate has been reported between these interventions in randomised controlled trials.
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      • Hinchliffe R.J.
      • Bruijstens L.
      • MacSweeney S.T.
      • Braithwaite B.D.
      A randomised trial of endovascular and open surgery for ruptured abdominal aortic aneurysm – results of a pilot study and lessons learned for future studies.
      • Powell J.T.
      • Sweeting M.J.
      • Thompson M.M.
      • Ashleigh R.
      • Bell R.
      • Gomes M.
      • et al.
      Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.
      For this reason, midterm outcomes are starting to be of interest in the debate on whether EVAR or OR is to be preferred for patients with a RAAA.
      • Powell J.T.
      • Sweeting M.J.
      • Thompson M.M.
      • Ashleigh R.
      • Bell R.
      • Gomes M.
      • et al.
      Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.
      • 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.
      • Bjorck M.
      • Mani K.
      Improving outcomes for ruptured abdominal aortic aneurysm.
      Midterm includes the 5 year period after primary intervention. In elective aortic surgery, the midterm risk of re-intervention and aneurysm rupture is higher after EVAR than after OR.
      • Stather P.W.
      • Sidloff D.
      • Dattani N.
      • Choke E.
      • Bown M.J.
      • Sayers R.D.
      Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm.
      Midterm outcomes after acute intervention may also differ. Therefore, midterm outcomes may give new insights into the preferred intervention in patients with a RAAA or guide post-intervention surveillance strategies. In the present study, re-intervention and survival rates 5 years after EVAR and OR for a RAAA were compared.

      Material and Methods

      The present study was an observational cohort study and reports follow up data from the previously published Amsterdam Acute Aneurysm (AJAX) trial (ISRCTN 66212637), which was conducted in the Amsterdam ambulance region. This ambulance region comprises 10 hospitals and 1.38 million inhabitants.
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      • van Beek S.C.
      • Reimerink J.J.
      • Vahl A.C.
      • Wisselink W.
      • Reekers J.A.
      • van Geloven N.
      • et al.
      Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm.
      Between April 2004 and February 2011, all consecutive patients with a RAAA in the region were registered prospectively and of these, all who underwent surgical treatment were included in the present study. Only patients whose demographics or short-term outcome were unknown were excluded.
      In the Amsterdam ambulance region between 2004 and 2011, care was concentrated into three vascular centres with a 24 hour full emergency vascular service in cooperation with the seven referring regional hospitals.
      • van Beek S.C.
      • Reimerink J.J.
      • Vahl A.C.
      • Wisselink W.
      • Reekers J.A.
      • van Geloven N.
      • et al.
      Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm.
      All patients suspected by the ambulance staff, general practitioner, or a surgeon in a referring hospital of having a RAAA were transported to a vascular centre. Only patients admitted to one of the seven referring hospitals, but who were deemed unfit for transfer, were treated locally. The three vascular centres treated patients by both EVAR and OR and the seven referring regional hospitals offered OR only. To assess suitability for EVAR, patients were evaluated with computed tomographic angiography (CTA). Patients suitable for both EVAR and OR were consented to be randomised between the interventions in the AJAX trial. The AJAX trial adhered to the CONSORT 2010 statement
      and details regarding the design, primary outcome, sample size, randomisation procedure and informed consent procedure have been published previously.
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      After discharge patients had routine follow up according to local practice. EVAR follow up included either yearly computed tomographic angiography (CTA) or duplex ultrasound combined with plain abdominal x-ray. The follow up and rationale for re-intervention including the handling of type II endoleaks, were left to the discretion of the treating physician and were not standardised in the context of the present study.
      The study was conducted in accordance with the principles of the Declaration of Helsinki and the present report includes all items recommended by the STrengthening the Reporting of Observational studies in Epidemiology (STROBE) statement.
      • Von E.E.
      • Altman D.G.
      • Egger M.
      • Pocock S.J.
      • Gotzsche P.C.
      • Vandenbroucke J.P.
      The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.

      End point

      The primary end point was re-intervention within 5 years of the primary intervention. The secondary end point was death. Re-interventions were defined according to the reporting standards
      • Chaikof E.L.
      • Blankensteijn J.D.
      • Harris P.L.
      • White G.H.
      • Zarins C.K.
      • Bernhard V.M.
      • et al.
      Reporting standards for endovascular aortic aneurysm repair.
      and comprised both surgical and endovascular procedures. Indications for re-intervention included abdominal compartment syndrome, access site infection, anastomotic aneurysm, re-bleeding, bowel ischaemia, endograft migration, endoleak (type I – IV), false aneurysm, graft thrombosis or obstruction, graft infection including aorto-enteric fistula, incisional hernia including other abdominal wall complications such as full thickness dehiscence, ischaemia of lower limbs including major amputations and peripheral fasciotomy, secondary aneurysm rupture, secondary symptomatic aneurysm and symptomatic adhesions.

      Data collection

      Data were collected up to January 2014 using Microsoft Office Access 2003 (Microsoft Corporation, Redmond, WA, USA) and included field limits and multivariate checks. Dates of death were obtained stepwise from the hospital registries (1), from the registry of the general practitioner (2), or from the communal registry of death certificates (3). Data regarding re-interventions and their indications were collected from hospital medical records and the general practitioners were asked for information on re-interventions in other hospitals. Patients whose follow up was unknown were censored in the analysis at the last point of contact. Data collection for EVAR and OR patients was done in the same way.

      Statistical analysis

      Continuous data were described by the median with corresponding interquartile range (IQR) because of a skewed distribution. Baseline characteristics were compared using the chi-square test and the Mann-Whitney U test (two sided; α = .05). The re-intervention and survival rates were estimated by Kaplan-Meier survival analysis and compared using the logrank test. Re-intervention rates were reported as freedom from re-intervention with corresponding events and surrounding 95% confidence intervals (CI). In the Kaplan-Meier survival analyses of the re-intervention rates, patients who died were censoed.
      Two subgroup analyses were conducted. The first subgroup included patients who survived their hospital stay and the first 30 days after the primary intervention. The second subgroup included patients from the AJAX trial in whom treatment allocation was done using randomisation. This subgroup analysis provided follow up data for all patients (EVAR n = 57, OR n = 59) included in the AJAX trial and was analysed according to the intention to treat principle.
      Two multivariable Cox proportional hazards models were developed to assess the association between type of intervention and re-intervention after adjustment for possible confounders. The first Cox model included all patients and the association between type of intervention and re-intervention was adjusted for age, sex, comorbidity, and haemodynamic stability based on pre-operative cardiopulmonary resuscitation and lowest in hospital systolic blood pressure. To include all patients in this analysis, an imputation procedure was done for missing data, of which details have been published previously.
      • van Beek S.C.
      • Reimerink J.J.
      • Vahl A.C.
      • Wisselink W.
      • Reekers J.A.
      • van Geloven N.
      • et al.
      Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm.
      The second Cox model included patients of the first subgroup who survived their hospital stay and the association between type of intervention and re-intervention was adjusted for age and sex.

      Results

      Between 2004 and 2011, 539 patients with a RAAA were admitted to one of the 10 hospitals in the Amsterdam ambulance region. Six patients whose demographics or outcome were unknown and 66 patients without surgical intervention were excluded from the analysis (Fig. 1). Of 467 patients included in the analysis, 407 were treated in the vascular centres and 60 in the referring hospitals.
      Figure thumbnail gr1
      Figure 1Flowchart of inclusion in all 467 patients (main analysis), in 297 patients who survived their hospital stay (subgroup 1), and in 116 patients randomised in the AJAX trial (subgroup 2).
      The baseline characteristics are shown per type of intervention in Table 1. Patients treated with EVAR showed a tendency towards higher pre-operative systolic blood pressure (SBP) (p = .07), and required less pre-operative cardiopulmonary resuscitation (CPR). Five years after the primary intervention, the overall survival rate was 38% (280/467, 95% CI: 33–43%) and the median follow up was 2.2 years (interquartile range 0.0–5.0 years). Eighteen patients (3 for EVAR, 15 for OR) were lost to follow up and censored at the last point of contact. Fifty-eight patients received the Talent endograft (Medtronic AVE Europe), seven patients the Endurant endograft (Medtronic BV, Heerlen), and the remaining eight patients received another or unknown endograft.
      Table 1Baseline characteristics.
      Original dataImputed data
      EVAR

      n = 73
      OR

      n = 394
      pMissing dataEVAROR
      Age, median (IQR)76 (69–80)76 (69–82).70
      Mann-Whitney test.
      0NINI
      Female sex12% (9/73)20% (80/394).11
      Chi-square statistic.
      0NINI
      Cardiac comorbidity48% (35/73)42% (158/379).32
      Chi-square statistic.
      3% (15/467)NI42% (165/394)
      Pulmonary comorbidity27% (20/73)20% (76/376).17
      Chi-square statistic.
      4% (18/467)NI20% (80/394)
      Renal comorbidity10% (7/73)12% (45/377).57
      Chi-square statistic.
      4% (17/467)NI12% (47/394)
      Cerebrovascular comorbidity15% (11/73)15% (58/378).95
      Chi-square statistic.
      3% (16/467)NI15% (60/394)
      CPR4% (3/73)12% (45/374).05
      Chi-square statistic.
      4% (20/467)NI13% (51/394)
      SBP, median (IQR)90 (75–129)90 (69–125).07
      Mann-Whitney test.
      11% (50/467)90 (76–126)90 (68–123)
      CPR = cardiopulmonary resuscitation; SBP = lowest in hospital systolic blood pressure in mmHg; NI = not imputed.
      a Mann-Whitney test.
      b Chi-square statistic.

      All patients

      Five years after the primary intervention, the rates of freedom from re-intervention were 55% for EVAR (26/73, 95% CI 41–69%) and 60% for OR (130/394, 95% CI: 55–66%) (p = .96, Fig. 2A). After multivariate adjustment for possible confounders, the risk of re-intervention was similar after EVAR and OR (HR 1.01, 95% CI: 0.65–1.55, Table 2). The survival rates after 5 years were 36% for EVAR (45/73, 95% CI: 24–47%) and 38% for OR (235/394, 95% CI: 33–43%) (p = .83, Fig. 3).
      Figure thumbnail gr2
      Figure 2Kaplan–Meier estimates of the freedom from re-intervention during the 5 year follow up in all patients (A, left), in the subgroup of patients who survived their hospital stay (B, middle), and in the subgroup of patients randomised in the AJAX trial (C, right).
      Table 2Multivariate Cox regression models to assess the association between type of intervention (endovascular versus open repair) and re-intervention in all patients and in the subgroup of patients who survived their hospital stay.
      All patients
      The model included 467 patients and 156 events. Age and SBP were categorised because of non-linearity.
      Patients who survived their hospital stay
      The model included 297 patients and 35 events.
      Hazard ratio (95% CI)Hazard ratio
      Age<69 (n = 114)Reference categoryNI
      69–76 (n = 117)1.35 (0.87–2.11)
      76–80 (n = 105)1.37 (0.86–2.18)
      >80 (n = 131)0.85 (0.52–1.39)
      Age per yearNI0.95 (0.92–0.99)
      p < .05.
      Female sex1.09 (0.72–1.65)0.98 (0.38–2.52)
      Cardiac comorbidity1.13 (0.81–1.58)NI
      Pulmonary comorbidity1.01 (0.67–1.52)NI
      Renal comorbidity1.01 (0.59–1.73)NI
      Cerebrovascular comorbidity0.83 (0.51–1.36)NI
      CPR1.47 (0.84–2.58)NI
      SBP<70 (n = 112)Reference categoryNI
      70–90 (n = 101)1.38 (0.82–2.32)
      90–125 (n = 137)1.28 (0.78–2.11)
      >125 (n = 117)0.71 (0.41–1.22)
      Open repair1.01 (0.65–1.55)0.27 (0.14–0.52)
      p < .05.
      CPR = cardiopulmonary resuscitation; SBP = lowest in hospital systolic blood pressure in mmHg; CI = confidence interval; NI = not included.
      a The model included 467 patients and 156 events. Age and SBP were categorised because of non-linearity.
      b The model included 297 patients and 35 events.
      c p < .05.
      Figure thumbnail gr3
      Figure 3Kaplan–Meier estimates of the overall survival during the 5 year follow up in all patients.
      After EVAR, during a follow up of 180.3 person years, there were 45 re-interventions in 26 of 73 patients. Sixteen patients had one re-intervention, seven patients had two, and three patients had three or more re-interventions. The most frequent indications for in hospital re-intervention were bowel ischaemia (5/22) and endoleak (4/22), and for re-intervention after discharge were endoleak (6/23) and graft infection (5/23) (Table 3). Eight of 45 (18%) re-interventions were endovascular. Of note, in nine patients a conversion to OR during the primary intervention was necessary based on access problems (n = 4), endoleak type I (n = 2), endoleak type III (n = 2), and failed deployment (n = 1). Because conversion happened during the primary intervention, they were not included in the present analysis.
      Table 3Indications for re-intervention after EVAR and OR.
      In hospitalAfter discharge
      EVAR (total number = 22)OR (total number = 195)EVAR (total number = 23)OR (total number = 29)
      Abdominal compartment syndrome9% (2)6% (11)4% (1)0
      Access site infection5% (1)1% (2)07% (2)
      Anastomotic aneurysm0000
      Re-bleeding9% (2)25% (48)03% (1)
      Bowel ischaemia23% (5)25% (49)13% (3)17% (5)
      Endograft migration9% (2)09% (2)
      One migration in combination with type I endoleak.
      0
      Endoleak18% (4)
      Four type I endoleaks.
      022% (5)
      Two type I endoleaks, three type II endoleaks.
      0
      False aneurysm009% (2)0
      Graft thrombosis or obstruction009% (2)3% (1)
      Graft infection5% (1)3% (5)22% (5)24% (7)
      Two in combination with secondary rupture, one aorto-enteric fistula.
      Incisional hernia5% (1)9% (18)13% (3)21% (6)
      Lower limb ischaemia14% (3)22% (42)07% (2)
      Secondary ruptured aneurysm0000
      One patient with secondary rupture verified by autopsy without re-intervention.
      Secondary symptomatic aneurysm0003% (1)
      Symptomatic adhesions01% (2)014% (4)
      Other5% (1)4% (8)00
      Unknown05% (10)00
      CI = 95% confidence interval.
      a One migration in combination with type I endoleak.
      b Four type I endoleaks.
      c Two type I endoleaks, three type II endoleaks.
      d Two in combination with secondary rupture, one aorto-enteric fistula.
      e One patient with secondary rupture verified by autopsy without re-intervention.
      After OR during a follow up of 927.4 person years, there was a total number of 224 re-interventions in 130 of 394 patients. Seventy-eight patients had one re-intervention, 27 had two, and 25 patients had three or more re-interventions. The most frequent indications for in hospital re-intervention were re-bleeding (49/195), bowel ischaemia (48/195), and ischaemia of lower limbs (42/195), and for re-intervention after discharge were graft infection (7/29) and incisional hernia (6/29) (Table 3). Ten of 224 re-interventions (4%) were endovascular.

      Subgroup analysis of discharged patients

      Of 467 patients included in the main analysis, 54 of 73 patients survived their hospital stay after EVAR and 243 of 394 patients survived their hospital stay after OR. These 297 patients were further studied in the first subgroup including the patients who survived their hospital stay (Fig. 1). In patients who survived their hospital stay, the rates of freedom from re-intervention were 66% for EVAR (15/54, 95% CI: 52–81%), and 90% for OR (20/243, 95% CI: 86–95%) (p < .01, Fig. 2B). After multivariate adjustment for possible confounders, the risk of re-intervention was lower after OR (HR 0.27, 95% CI: 0.14–0.52, Table 2). The overall survival analysis in these patients is reported as an online supplement (Fig. S1, online supplement).

      Subgroup analysis of randomised patients

      Of 467 patients included in the main analysis, 113 were also randomised between EVAR and OR in the AJAX trial and were further studied in this second subgroup (Fig. 1). Because of the intention to treat principle, three patients with a discharge diagnosis other than RAAA were also included in the AJAX trial and therefore added to this subgroup. The baseline data of the AJAX trial have been published previously.
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      The rates of freedom from re-intervention were 52% for EVAR (22/57, 95% CI 37–68%) and 59% for OR (20/59, 95% CI 45–74%) (p = .71, Fig. 2C). The overall survival analysis in these patients is reported as an online supplement (Fig. S2, online supplement).

      Discussion

      The present study in patients with a ruptured abdominal aortic aneurysm shows that 5 years after the primary intervention the re-intervention and survival rates for endovascular and open repair are similar. In patients who survive their hospital stay the re-intervention rate for EVAR is higher than for OR.

      Indications for re-intervention

      Some clear observations can be made from the indications for re-intervention (Table 3). Comparing EVAR and OR, there appears to be a benefit for EVAR with regard to re-bleeding. However, the numbers are small and therefore power is limited for this comparison. In patients whose indication for first re-intervention was re-bleeding, bowel or lower limb ischaemia, the mortality rate was 52% (46/88) emphasising the importance of these complications. The number of re-interventions for graft infection were significant after both EVAR (6/45) and OR (12/224). The most likely explanation is the high number of bowel ischaemia related problems leading to contaminated abdomen.
      The numbers of secondary ruptures (n = 0) or symptomatic aneurysms (n = 3) were low after both EVAR and OR. This is surprising considering the rate of secondary rupture after elective EVAR. Possibly, follow up was too short and ruptures will occur later in this cohort. Another explanation is that secondary ruptures were only considered an event when re-intervention was performed. To illustrate this, one patient had a secondary rupture verified through autopsy but was not treated surgically. Finally, patients might have died from a secondary rupture without the authors' knowledge. Cause of death was considered to be unreliable because of a very low number of autopsies.

      Confounding

      In the Amsterdam ambulance region, patients received treatment based on the possibility of being able to transport the patient to a vascular centre, suitability for EVAR, and randomisation in the AJAX trial. In general, haemodynamically unstable patients had open repair whereas haemodynamically stable patients had EVAR. The potential problem of confounding was addressed in two ways, First, using multivariate adjustment (Table 2), and, second, using randomisation by further studying patients who had been included in the AJAX trial (subgroup 2). The results of both methods confirm the conclusions of the main analysis that re-intervention and survival rates are similar, but that patients who survive their hospital stay have a higher re-intervention rate after EVAR.
      A limitation of the multivariable analyses is that there is a risk of residual confounding. Moreover, in the hazard plot a similar pattern to Figure 2A was seen; during the in hospital period there were fewer re-interventions after EVAR and during follow up there were fewer re-interventions after OR. In this way, the risk of re-intervention after both interventions was balanced in ratio, whereas the hazard plot was a bit more nuanced. The limitation of the AJAX trial is that the number of patients included was quite low for midterm outcomes and the results were therefore statistically not significant.

      Midterm outcomes

      Most studies comparing EVAR and OR for RAAA focus on short-term outcomes, and only five studies
      • Mani K.
      • Bjorck M.
      • Lundkvist J.
      • Wanhainen A.
      Improved long-term survival after abdominal aortic aneurysm repair.
      • Mehta M.
      • Byrne J.
      • Darling III, R.C.
      • Paty P.S.
      • Roddy S.P.
      • Kreienberg P.B.
      • et al.
      Endovascular repair of ruptured infrarenal abdominal aortic aneurysm is associated with lower 30-day mortality and better 5-year survival rates than open surgical repair.
      • Rollins K.E.
      • Shak J.
      • Ambler G.K.
      • Tang T.Y.
      • Hayes P.D.
      • Boyle J.R.
      Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm.
      • Wallace G.A.
      • Starnes B.W.
      • Hatsukami T.S.
      • Quiroga E.
      • Tang G.L.
      • Kohler T.R.
      • et al.
      Favorable discharge disposition and survival after successful endovascular repair of ruptured abdominal aortic aneurysm.
      • Edwards S.T.
      • Schermerhorn M.L.
      • O'Malley A.J.
      • Bensley R.P.
      • Hurks R.
      • Cotterill P.
      • et al.
      Comparative effectiveness of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Medicare population.
      have so far reported midterm outcomes. The present study expands on these studies by prospective patient identification, by multi-centre design representing 10 hospitals from one ambulance region, and by subgroup analysis with randomised treatment allocation. Several conclusions can be drawn by interpreting the present results in light of previous studies.
      It is known that in elective aortic surgery, the midterm risk of re-intervention is higher after EVAR than after OR.
      • Stather P.W.
      • Sidloff D.
      • Dattani N.
      • Choke E.
      • Bown M.J.
      • Sayers R.D.
      Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm.
      In agreement with a previous study,
      • Rollins K.E.
      • Shak J.
      • Ambler G.K.
      • Tang T.Y.
      • Hayes P.D.
      • Boyle J.R.
      Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm.
      the present study shows that there is no difference in re-intervention rates after an acute intervention. Because the present study (n = 73) and the previous study (n = 62) included limited numbers of patients treated by EVAR, more data are required before definite conclusions can be drawn. An interesting observation from both these studies is that during the in hospital period there were fewer re-interventions after EVAR and during follow up there were fewer re-interventions after OR (Fig. 2A).
      The present results confirm previous results that in patients who survive their hospital stay the re-intervention rate is higher after EVAR than after OR (Fig. 2B).
      • Rollins K.E.
      • Shak J.
      • Ambler G.K.
      • Tang T.Y.
      • Hayes P.D.
      • Boyle J.R.
      Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm.
      • Edwards S.T.
      • Schermerhorn M.L.
      • O'Malley A.J.
      • Bensley R.P.
      • Hurks R.
      • Cotterill P.
      • et al.
      Comparative effectiveness of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Medicare population.
      This conclusion echoes the results after elective aortic surgery.
      • Stather P.W.
      • Sidloff D.
      • Dattani N.
      • Choke E.
      • Bown M.J.
      • Sayers R.D.
      Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm.
      It was not recorded whether the indications for re-intervention were found by routine follow up or by an acute event. For this reason, no definite conclusions could be drawn about the need for routine follow up after EVAR for RAAA.
      The overall survival rate of all patients in the present study (38%, 95% CI: 34–43%) corresponds with a previously reported 5 year survival of 44% (99% CI: 40–47%).
      • Mani K.
      • Bjorck M.
      • Lundkvist J.
      • Wanhainen A.
      Improved long-term survival after abdominal aortic aneurysm repair.
      This indicates that the 5 year survival after RAAA is low; around 40%.
      In the present study, results regarding the midterm survival after EVAR and OR were conflicting. In all patients, the survival rates 5 years after the primary intervention were similar for EVAR and for OR (Fig. 3). In patients who survived their hospital stay, there was a conspicuously higher survival rate for OR (Fig. S1, online supplement). Conversely, the subgroup analysis in the AJAX trial showed similar survival rates for both interventions in all patients and in patients who survived their hospital stay (Fig. S2, online supplement). The same conflicting results can be found on assessing the outcomes of previous studies. One study
      • Rollins K.E.
      • Shak J.
      • Ambler G.K.
      • Tang T.Y.
      • Hayes P.D.
      • Boyle J.R.
      Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm.
      reported similar survival rates, whereas other studies reported lower survival rates for EVAR.
      • Mani K.
      • Bjorck M.
      • Lundkvist J.
      • Wanhainen A.
      Improved long-term survival after abdominal aortic aneurysm repair.
      • Mehta M.
      • Byrne J.
      • Darling III, R.C.
      • Paty P.S.
      • Roddy S.P.
      • Kreienberg P.B.
      • et al.
      Endovascular repair of ruptured infrarenal abdominal aortic aneurysm is associated with lower 30-day mortality and better 5-year survival rates than open surgical repair.
      • Wallace G.A.
      • Starnes B.W.
      • Hatsukami T.S.
      • Quiroga E.
      • Tang G.L.
      • Kohler T.R.
      • et al.
      Favorable discharge disposition and survival after successful endovascular repair of ruptured abdominal aortic aneurysm.
      • Edwards S.T.
      • Schermerhorn M.L.
      • O'Malley A.J.
      • Bensley R.P.
      • Hurks R.
      • Cotterill P.
      • et al.
      Comparative effectiveness of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Medicare population.
      It appears probable that patient selection for EVAR significantly influences these midterm survival rates. Because randomised treatment allocation adjusts for this patient selection, the results of the subgroup analysis in the AJAX trial guide us towards the conclusion that the midterm survival rates for EVAR and for OR are comparable.
      Finally, the 5 year re-intervention rate after discharge for EVAR of 34% (95% CI: 19–48%) in the present study was high compared with the 6 year re-intervention rate for EVAR of 30% in the Dutch Randomized Endovascular Aneurysm Repair trial.
      • De Bruin J.L.
      • Baas A.F.
      • Buth J.
      • Prinssen M.
      • Verhoeven E.L.
      • Cuypers P.W.
      • et al.
      Long-term outcome of open or endovascular repair of abdominal aortic aneurysm.
      The use of aorto-uni-iliac endografts could offer an explanation, although no studies have demonstrated that these endografts carry a higher risk of re-intervention. On the contrary, studies addressing this issue in elective aortic surgery have reported comparable outcomes in aorto-uni-iliac and bifurcated endografts after multivariate adjustment for patient selection.
      • Jean-Baptiste E.
      • Batt M.
      • Azzaoui R.
      • Koussa M.
      • Hassen-Khodja R.
      • Haulon S.
      A comparison of the mid-term results following the use of bifurcated and aorto-uni-iliac devices in the treatment of abdominal aortic aneurysms.
      • Tang T.
      • Sadat U.
      • Walsh S.
      • Hayes P.D.
      Comparison of the endurant bifurcated endograft vs. aortouni-iliac stent-grafting in patients with abdominal aortic aneurysms: experience from the ENGAGE registry.
      A more plausible explanation is that time is limited for planning the intervention and sizing the endograft, leading to migration or endoleaks. Moreover, sizing of the endograft may be affected by the CT scan of hypovolaemic patients showing a smaller aorta.

      Preferred intervention

      The present study adds evidence to the debate on whether EVAR or OR is to be preferred for patients with a RAAA. The randomised trials reported similar short-term survival rates for both EVAR and OR.
      • 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.
      EVAR appears to be beneficial on secondary outcomes such as less blood loss, less need for mechanical ventilation and temporary dialysis, a shorter intensive care and hospital stay, and more patients being discharged home.
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      • Powell J.T.
      • Sweeting M.J.
      • Thompson M.M.
      • Ashleigh R.
      • Bell R.
      • Gomes M.
      • et al.
      Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.
      In a direct comparison of costs after 30 days between EVAR and OR in the AJAX trial, EVAR was more expensive.
      • Kapma M.R.
      • Dijksman L.M.
      • Reimerink J.J.
      • de Groof A.J.
      • Zeebregts C.J.
      • Wisselink W.
      • et al.
      Cost-effectiveness and cost-utility of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Amsterdam Acute Aneurysm Trial.
      In a comparison of costs after 30 days between the endovascular and open strategy in the IMPROVE trial, costs were comparable.
      • Powell J.T.
      • Sweeting M.J.
      • Thompson M.M.
      • Ashleigh R.
      • Bell R.
      • Gomes M.
      • et al.
      Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.
      This indicates that EVAR is more expensive than OR, but that a treatment strategy offering both EVAR and OR is not more expensive than a treatment strategy including only OR. With the results of the present study in mind, when deciding between EVAR and OR in the acute setting, caregivers have to balance the short-term benefit of secondary outcomes after EVAR with the lower midterm risk of re-intervention after discharge for OR. In future, it is to be expected that new endografts will improve midterm outcomes after EVAR.

      Limitations

      A limitation of the present study was that complications not requiring surgical intervention were not included. For example, an incisional hernia in a patient who was considered to be unfit for re-intervention was not included. Hence, the re-intervention incidence rates do not reflect the true incidence of the complications.
      There are also some limitations to the external validity of the present results. Although the outcomes after EVAR are restricted to aorto-uni-iliac endografts, in elective aortic surgery comparable outcomes in aorto-uni-iliac and bifurcated endografts have been reported.
      • Jean-Baptiste E.
      • Batt M.
      • Azzaoui R.
      • Koussa M.
      • Hassen-Khodja R.
      • Haulon S.
      A comparison of the mid-term results following the use of bifurcated and aorto-uni-iliac devices in the treatment of abdominal aortic aneurysms.
      • Tang T.
      • Sadat U.
      • Walsh S.
      • Hayes P.D.
      Comparison of the endurant bifurcated endograft vs. aortouni-iliac stent-grafting in patients with abdominal aortic aneurysms: experience from the ENGAGE registry.
      In general, indications for re-intervention vary between hospitals and over time. As mentioned before, the number of patients treated by EVAR was low (n = 73). The sample size of the present study was based on the AJAX trial,
      • Reimerink J.J.
      • Hoornweg L.L.
      • Vahl A.C.
      • Wisselink W.
      • van den Broek T.A.
      • Legemate D.A.
      • et al.
      Endovascular repair versus open repair of ruptured abdominal aortic aneurysms: a multicenter randomized controlled trial.
      and therefore only a post hoc power calculation could be done. Considering the re-intervention rate of 40% after OR and 73 patients treated with EVAR, the present study had 80% power to pick up 5 year re-intervention rates after EVAR of <18% or of >64% (2 sided significance level α = .05, β = .20). This clearly demonstrates that the present study was underpowered, and that more studies are needed to confirm a smaller difference in re-intervention rates.
      Of those patients evaluated with a CTA in the Amsterdam ambulance region, only 49% were considered to have aorto-iliac anatomy suitable for EVAR.
      • van Beek S.C.
      • Reimerink J.J.
      • Vahl A.C.
      • Wisselink W.
      • Reekers J.A.
      • Legemate D.A.
      • et al.
      Outcomes after open repair for ruptured abdominal aortic aneurysms in patients with friendly versus hostile aortoiliac anatomy.
      This is rather low compared with the suitability rate of 64% in the IMPROVE trial.
      • Powell J.T.
      • Sweeting M.J.
      • Thompson M.M.
      • Ashleigh R.
      • Bell R.
      • Gomes M.
      • et al.
      Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.
      Caregivers in the Amsterdam region mostly adhered to the instructions for use (IFU) because few data or guidelines are available on the use of endografts outside the IFU. In elective aortic repair, patients treated outside the IFU have a higher risk of adverse events.
      • Antoniou G.A.
      • Georgiadis G.S.
      • Antoniou S.A.
      • Kuhan G.
      • Murray D.
      A meta-analysis of outcomes of endovascular abdominal aortic aneurysm repair in patients with hostile and friendly neck anatomy.
      For this reason, the midterm re-intervention rates in the Amsterdam region were probably low compared with hospitals pushing the anatomical limits of EVAR for RAAAs.

      Conclusions

      Five years after the primary intervention, endovascular and open repair for a ruptured abdominal aortic aneurysm resulted in similar re-intervention and survival rates. However, in patients who survived their hospital stay the re-intervention rate was higher for EVAR than for OR.

      Conflict of Interest

      None.

      Funding

      The present study was funded partially by the Academic Medical Centre Amsterdam (AMC) Foundation and the Netherlands Heart Foundation (project: 2002B197 ). The sponsor had no involvement in the study design, in the collection, analysis and interpretation of data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.

      Acknowledgements

      The present study was conducted on behalf of the Amsterdam Acute Aneurysm Trial Collaborators (listed below).

      Appendix A.

      The list of Amsterdam Acute Aneurysm Trial Collaborators is as follows: centers (number of included patients);
      Academic Medical Center (39); R. Balm, M.J.W. Koelemay, M.M. Idu, C. Kox, D.A. Legemate, L.C. Huisman, M.C.M. Willems, J.A. Reekers, O.M. van Delden, K.P. van Lienden,
      Trial coordinators: L.L. Hoornweg, J.J. Reimerink, S.C. van Beek.
      Onze Lieve Vrouwe Gasthuis (46); A.C. Vahl, V.J. Leijdekkers, J. Bosma, A.D. Montaubanvan Swijndregt, C. de Vries, V.P.M. van der Hulst, J. Peringa, J.G.A.M. Blomjous, M.J.T. Visser, F.H.W.M. van der Heijden.
      VU-University Medical Center (31); W. Wisselink, A.W.J. Hoksbergen, J.D. Blankensteijn, M.T.J. Visser, H.M.E. Coveliers, J.H. Nederhoed, F.G. van den Berg, B.B. van der Meijs, M.L.P. van den Oever, R.J. Lely, M.R. Meijerink.
      Referring centers;
      Sint Lucas Andreas ziekenhuis; A. Voorwinde, J.M. Ultee, R.C. van Nieuwenhuizen
      Slotervaartziekenhuis; B.J. Dwars, T.O.M. Nagy
      BovenIJ ziekenhuis; P. Tolenaar, A.M. Wiersema
      Ziekenhuis Amstelland; J.A. Lawson, P.J. van Aken, A.A. Stigter
      Waterlandziekenhuis; T.A.A. van den Broek, G.A. Vos
      Zaans Medisch Centrum; W. Mulder, R.P. Strating
      Spaarne ziekenhuis; D. Nio, G.J.M. Akkersdijk, A. van der Elst
      Regional ambulance services; P. van Exter

      Appendix B. Supplementary data

      Figure thumbnail figs1
      Figure S1Kaplan–Meier estimates of the overall survival during five years of follow-up in patients who survived their hospital stay.
      Figure thumbnail figs2
      Figure S2Kaplan–Meier estimates of the overall survival during five years of follow-up in patients randomized in the AJAX trial.

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      Linked Article

      • The Importance of Re-interventions After Ruptured EVAR
        European Journal of Vascular and Endovascular SurgeryVol. 49Issue 6
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          Peri-operative survival is the most important and relevant outcome measure for treatment of an acutely life threatening disease, such as ruptured abdominal aortic aneurysm (rAAA). In this respect, endovascular and open repair of rAAAs have equal results in randomised trials. However, approximately 70% of patients with rAAAs survive the peri-operative period, and for these patients the long-term prognosis of the disease is of utmost importance.
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