Endovascular stent grafting and open surgical replacement for chronic thoracic aortic aneurysms: a systematic review and prospective cohort study

Linda Sharples, Priya Sastry, Carol Freeman, Joanne Gray, Andrew McCarthy, Yi-Da Chiu, Colin Bicknell, Peter McMeekin, S Rao Vallabhaneni, Andrew Cook, Luke Vale, Stephen Large, Linda Sharples, Priya Sastry, Carol Freeman, Joanne Gray, Andrew McCarthy, Yi-Da Chiu, Colin Bicknell, Peter McMeekin, S Rao Vallabhaneni, Andrew Cook, Luke Vale, Stephen Large

Abstract

Background: The management of chronic thoracic aortic aneurysms includes conservative management, watchful waiting, endovascular stent grafting and open surgical replacement. The Effective Treatments for Thoracic Aortic Aneurysms (ETTAA) study investigates timing and intervention choice.

Objective: To describe pre- and post-intervention management of and outcomes for chronic thoracic aortic aneurysms.

Design: A systematic review of intervention effects; a Delphi study of 360 case scenarios based on aneurysm size, location, age, operative risk and connective tissue disorders; and a prospective cohort study of growth, clinical outcomes, costs and quality of life.

Setting: Thirty NHS vascular/cardiothoracic units.

Participants: Patients aged > 17 years who had existing or new aneurysms of ≥ 4 cm in diameter in the arch, descending or thoracoabdominal aorta.

Interventions: Endovascular stent grafting and open surgical replacement.

Main outcomes: Pre-intervention aneurysm growth, pre-/post-intervention survival, clinical events, readmissions and quality of life; and descriptive statistics for costs and quality-adjusted life-years over 12 months and value of information using a propensity score-matched subsample.

Results: The review identified five comparative cohort studies (endovascular stent grafting patients, n = 3955; open surgical replacement patients, n = 21,197). Pooled short-term all-cause mortality favoured endovascular stent grafting (odds ratio 0.71, 95% confidence interval 0.51 to 0.98; no heterogeneity). Data on survival beyond 30 days were mixed. Fewer short-term complications were reported with endovascular stent grafting. The Delphi study included 20 experts (13 centres). For patients with aneurysms of ≤ 6.0 cm in diameter, watchful waiting was preferred. For patients with aneurysms of > 6.0 cm, open surgical replacement was preferred in the arch, except for elderly or high-risk patients, and in the descending aorta if patients had connective tissue disorders. Otherwise endovascular stent grafting was preferred. Between 2014 and 2018, 886 patients were recruited (watchful waiting, n = 489; conservative management, n = 112; endovascular stent grafting, n = 150; open surgical replacement, n = 135). Pre-intervention death rate was 8.6% per patient-year; 49.6% of deaths were aneurysm related. Death rates were higher for women (hazard ratio 1.79, 95% confidence interval 1.25 to 2.57; p = 0.001) and older patients (age 61-70 years: hazard ratio 2.50, 95% confidence interval 0.76 to 5.43; age 71-80 years: hazard ratio 3.49, 95% confidence interval 1.26 to 9.66; age > 80 years: hazard ratio 7.01, 95% confidence interval 2.50 to 19.62; all compared with age < 60 years, p < 0.001) and per 1-cm increase in diameter (hazard ratio 1.90, 95% confidence interval 1.65 to 2.18; p = 0.001). The results were similar for aneurysm-related deaths. Decline per year in quality of life was greater for older patients (additional change -0.013 per decade increase in age, 95% confidence interval -0.019 to -0.007; p < 0.001) and smokers (additional change for ex-smokers compared with non-smokers 0.003, 95% confidence interval -0.026 to 0.032; additional change for current smokers compared with non-smokers -0.034, 95% confidence interval -0.057 to -0.01; p = 0.004). At the time of intervention, endovascular stent grafting patients were older (age difference 7.1 years; 95% confidence interval 4.7 to 9.5 years; p < 0.001) and more likely to be smokers (75.8% vs. 66.4%; p = 0.080), have valve disease (89.9% vs. 71.6%; p < 0.0001), have chronic obstructive pulmonary disease (21.3% vs. 13.3%; p = 0.087), be at New York Heart Association stage III/IV (22.3% vs. 16.0%; p = 0.217), have lower levels of haemoglobin (difference -6.8 g/l, 95% confidence interval -11.2 to -2.4 g/l; p = 0.003) and take statins (69.3% vs. 42.2%; p < 0.0001). Ten (6.7%) endovascular stent grafting and 15 (11.1%) open surgical replacement patients died within 30 days of the procedure (p = 0.2107). One-year overall survival was 82.5% (95% confidence interval 75.2% to 87.8%) after endovascular stent grafting and 79.3% (95% confidence interval 71.1% to 85.4%) after open surgical replacement. Variables affecting survival were aneurysm site, age, New York Heart Association stage and time waiting for procedure. For endovascular stent grafting, utility decreased slightly, by -0.017 (95% confidence interval -0.062 to 0.027), in the first 6 weeks. For open surgical replacement, there was a substantial decrease of -0.160 (95% confidence interval -0.199 to -0.121; p < 0.001) up to 6 weeks after the procedure. Over 12 months endovascular stent grafting was less costly, with higher quality-adjusted life-years. Formal economic analysis was unfeasible.

Limitations: The study was limited by small numbers of patients receiving interventions and because only 53% of patients were suitable for both interventions.

Conclusions: Small (4-6 cm) aneurysms require close observation. Larger (> 6 cm) aneurysms require intervention without delay. Endovascular stent grafting and open surgical replacement were successful for carefully selected patients, but cost comparisons were unfeasible. The choice of intervention is well established, but the timing of intervention remains challenging.

Future work: Further research should include an analysis of the risk factors for growth/rupture and long-term outcomes.

Trial registration: Current Controlled Trials ISRCTN04044627 and NCT02010892.

Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 6. See the NIHR Journals Library website for further project information.

Keywords: AORTA AND TREATMENT OUTCOME; AORTIC ANEURYSM, THORACIC; HUMANS; TOMOGRAPHY, X-RAY COMPUTED.

References

    1. Clouse WD, Hallett JW, Schaff HV, Spittell PC, Rowland CM, Ilstrup DM, Melton LJ. Acute aortic dissection: population-based incidence compared with degenerative aortic aneurysm rupture. Mayo Clin Proc 2004;79:176–80.
    1. Bridgewater B, Keogh B, Kinsman R, Walton P. The Society for Cardiothoracic Surgery in Great Britain & Ireland: The Sixth National Adult Cardiac Surgical Database Report. Henley-on-Thames: Dendrite Clinical Systems Ltd; 2009.
    1. Bottle A, Mariscalco G, Shaw MA, Benedetto U, Saratzis A, Mariani S, et al. Unwarranted variation in the quality of care for patients with diseases of the thoracic aorta. J Am Heart Assoc 2017;6:e004913.
    1. Saliba E, Sia Y. The ascending aortic aneurysm: when to intervene? Int J Cardiol Heart Vasculature 2015;6:91–100.
    1. Ince H, Nienaber CA. Etiology, pathogenesis and management of thoracic aortic aneurysm. Nat Clin Pract Cardiovasc Med 2007;4:418–27.
    1. Ostberg NP, Zafar MA, Ziganshin BA, Elefteriades JA. The genetics of thoracic aortic aneurysms and dissection: a clinical perspective. Biomolecules 2020;10:E182.
    1. Pannu H, Fadulu VT, Chang J, Lafont A, Hasham SN, Sparks E, et al. Mutations in transforming growth factor-beta receptor type II cause familial thoracic aortic aneurysms and dissections. Circulation 2005;112:513–20.
    1. van Bogerijen GH, Tolenaar JL, Rampoldi V, Moll FL, van Herwaarden JA, Jonker FH, et al. Predictors of aortic growth in uncomplicated type B aortic dissection. J Vasc Surg 2014;59:1134–43.
    1. Bashir M, Fok M, Hammoud I, Rimmer L, Shaw M, Field M, et al. A perspective on natural history and survival in nonoperated thoracic aortic aneurysm patients. Aorta 2013;1:182–9.
    1. Juvonen T, Ergin MA, Galla JD, Lansman SL, McCullough JN, Nguyen K, et al. Risk factors for rupture of chronic type B dissections. J Thorac Cardiovasc Surg 1999;117:776–86.
    1. Patel HJ, Nguyen C, Diener AC, Passow MC, Salata D, Deeb GM. Open arch reconstruction in the endovascular era: analysis of 721 patients over 17 years. J Thorac Cardiovasc Surg 2011;141:1417–23.
    1. Higgins J, Lee MK, Co C, Janusz MT. Long-term outcomes after thoracic aortic surgery: a population-based study. J Thorac Cardiovasc Surg 2014;148:47–52.
    1. Thomas M, Li Z, Cook DJ, Greason KL, Sundt TM. Contemporary results of open aortic arch surgery. J Thorac Cardiovasc Surg 2012;144:838–44.
    1. Clouse WD, Cambria RP. Current status of thoracoabdominal aneurysm repair. Adv Surg 2004;38:197–246.
    1. Coady MA, Rizzo JA, Hammond GL, et al. What is the appropriate size criterion for resection of thoracic aortic aneurysms? J Thorac Cardiovasc Surg 1997;113:476–91; discussion 489–91.
    1. Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey Jr DE, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease. J Am Coll Cardiol 2010;55:e27–129.
    1. Erbel R, Aboyans V, Boileau C, Bossone E, Bartolomeo RD, Eggebrecht H, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J 2014;35:2873–926.
    1. Graves RS. Users’ guides to the medical literature: a manual for evidence-based clinical practice. J Med Library Assoc 2002;90:483.
    1. Elefteriades JA. Natural history of thoracic aortic aneurysms: indications for surgery, and surgical versus nonsurgical risks. Ann Thorac Surg 2002;74:S1877–80.
    1. Elefteriades JA. Indications for aortic replacement. J Thorac Cardiovasc Surg 2010;140(Suppl.):S5–9; discussion S45–51.
    1. International Registry of Acute Aortic Dissections (IRAD). The International Registry of Acute Aortic Dissections. URL: (accessed 19 October 2020).
    1. Boening A, Karck M, Conzelmann LO, Easo J, Krüger T, Rylski B, Weigang E. German Registry for acute aortic dissection type A: structure, results, and future perspectives. Thorac Cardiovasc Surg 2017;65:77–84.
    1. Yan T, Tian DH, LeMaire SA, Misfeld M, Elefteriades JA, Chen EP, et al. The ARCH Projects: design and rationale (IAASSG 001). Eur J Cardiothorac Surg 2014;45:5.
    1. Elefteriades JA, Ziganshin BA, Rizzo JA, Fang H, Tranquilli M, Paruchuri V, et al. Indications and imaging for aortic surgery: size and other matters. J Thorac Cardiovasc Surg 2015;149(Suppl. 2):10–13.
    1. Trimarchi S, Jonker FH, Hutchison S, et al. Descending aortic diameter of 5.5 cm or greater is not an accurate predictor of acute type B aortic dissection. J Thorac Cardiovasc Surg 2011;142:e101–7.
    1. Cheung K, Boodhwani M, Chan KL, Beauchesne L, Dick A, Coutinho T. Thoracic aortic aneurysm growth: role of sex and aneurysm etiology. J Am Heart Assoc 2017;6:e003792.
    1. Kuzmik GA, Sang AX, Elefteriades JA. Natural history of thoracic aortic aneurysms. J Vasc Surg 2012;56:565–71.
    1. Sueyoshi E, Sakamoto I, Uetani M. Growth rate of affected aorta in patients with type B partially closed aortic dissection. Ann Thorac Surg 2009;88:1251–7.
    1. Shimada I, Rooney SJ, Pagano D, Farneti PA, Davies P, Guest PJ, Bonser RS. Prediction of thoracic aortic aneurysm expansion: validation of formulae describing growth. Ann Thorac Surg 1999;67:1968–70.
    1. Dapunt OE, Galla JD, Sadeghi AM, Lansman SL, Mezrow CK, de Asla RA, et al. The natural history of thoracic aortic aneurysms. J Thorac Cardiovasc Surg 1994;107:1323–32.
    1. Gray J, McCarthy A, McMeekin P, Vale L, Freeman, Sharples L, et al. Effective Treatments for Thoracic Aortic Aneurysms (ETTAA study): Protocol for a Systematic Review. 2017. URL: (accessed 24 November 2021).
    1. McCarthy A, Gray J, Sastry P, Sharples L, Vale L, Cook A, et al. Systematic review of endovascular stent grafting versus open surgical repair for the elective treatment of arch/descending thoracic aortic aneurysms. BMJ Open 2021;11:e043323.
    1. Sterne JA, Hernán MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ 2016;355:i4919.
    1. Goodney PP, Travis L, Lucas FL, Fillinger MF, Goodman DC, Cronenwett JL, Stone DH. Survival after open versus endovascular thoracic aortic aneurysm repair in an observational study of the Medicare population. Circulation 2011;124:2661–9.
    1. Bavaria JE, Appoo JJ, Makaroun MS, Verter J, Yu ZF, Mitchell RS, Gore TAG Investigators. Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial. J Thorac Cardiovasc Surg 2007;133:369–77.
    1. von Allmen RS, Anjum A, Powell JT. Outcomes after endovascular or open repair for degenerative descending thoracic aortic aneurysm using linked hospital data. Br J Surg 2014;101:1244–51.
    1. Andrassy J, Weidenhagen R, Meimarakis G, Rentsch M, Jauch KW, Kopp R. Endovascular versus open treatment of degenerative aneurysms of the descending thoracic aorta: a single center experience. Vascular 2011;19:8–14.
    1. Hughes K, Guerrier J, Obirieze A, Ngwang D, Rose D, Tran D, et al. Open versus endovascular repair of thoracic aortic aneurysms: a nationwide inpatient sample study. Vasc Endovascular Surg 2014;48:383–7.
    1. Piffaretti G, Tozzi M, Lomazzi C, Rivolta N, Caronno R, Bacuzzi A, et al. Endovascular repair versus conventional surgery for descending thoracic aortic aneurysms. Ital J Vasc Endovasc Surg 2007;14:279–85.
    1. Desai ND, Burtch K, Moser W, Moeller P, Szeto WY, Pochettino A, et al. Long-term comparison of thoracic endovascular aortic repair (TEVAR) to open surgery for the treatment of thoracic aortic aneurysms. J Thorac Cardiovasc Surg 2012;144:604–9.
    1. Gopaldas RR, Huh J, Dao TK, LeMaire SA, Chu D, Bakaeen FG, Coselli JS. Superior nationwide outcomes of endovascular versus open repair for isolated descending thoracic aortic aneurysm in 11,669 patients. J Thorac Cardiovasc Surg 2010;140:1001–10.
    1. Orandi BJ, Dimick JB, Deeb GM, Patel HJ, Upchurch GR. A population-based analysis of endovascular versus open thoracic aortic aneurysm repair. J Vasc Surg 2009;49:1112–16.
    1. Dick F, Hinder D, Immer FF, Hirzel C, Do DD, Carrel TP, Schmidli J. Outcome and quality of life after surgical and endovascular treatment of descending aortic lesions. Ann Thorac Surg 2008;85:1605–12.
    1. Narayan P, Wong A, Davies I, Angelini GD, Bryan AJ, Wilde P, Murphy GJ. Thoracic endovascular repair versus open surgical repair – which is the more cost-effective intervention for descending thoracic aortic pathologies? Eur J Cardiothorac Surg 2011;40:869–74.
    1. National Institute for Health and Care Excellence. Abdominal Aortic Aneurysm: Diagnosis and Management. URL: (accessed 19 October 2020).
    1. National Institute for Health and Care Excellence (NICE). NICE Publishes its Guideline on the Diagnosis and Management of Abdominal Aortic Aneurysms. Press release, 19 March 2020. URL: (accessed 15 September 2020).
    1. Delbecq AL, Van de Ven AH. A group process model for problem identification and program planning. J Appl Behav Sci 1971;7:466–92.
    1. Fitch K, Bernstein SJ, Aguilar MD, Burnard B, LaCalle JR. The RAND/UCLA Appropriateness Method User’s Manual. Santa Monica, CA: RAND Corporation; 2001.
    1. Martin G, Riga C, Gibbs R, Jenkins M, Hamady M, Bicknell C. Short- and long-term results of hybrid arch and proximal descending thoracic aortic repair: a benchmark for new technologies. J Endovasc Ther 2016;23:783–90.
    1. Haulon S, Greenberg RK, Spear R, Eagleton M, Abraham C, Lioupis C, et al. Global experience with an inner branched arch endograft. J Thorac Cardiovasc Surg 2014;148:1709–16.
    1. Ince H, Rehders TC, Petzsch M, Kische S, Nienaber CA. Stent-grafts in patients with marfan syndrome. J Endovasc Ther 2005;12:82–8.
    1. Geisbüsch P, Kotelis D, von Tengg-Kobligk H, Hyhlik-Dürr A, Allenberg JR, Böckler D. Thoracic aortic endografting in patients with connective tissue diseases. J Endovasc Ther 2008;15:144–9.
    1. Pellenc Q, Girault A, Roussel A, De Blic R, Cerceau P, Raffoul R, et al. Optimising aortic endovascular repair in patients with Marfan syndrome. Eur J Vasc Endovasc Surg 2020;59:577–85.
    1. Hicks CW, Lue J, Glebova NO, Ehlert BA, Black JH. A 10-year institutional experience with open branched graft reconstruction of aortic aneurysms in connective tissue disorders versus degenerative disease. J Vasc Surg 2017;66:1406–16.
    1. Verhoeven EL, Katsargyris A, Bekkema F, et al. Editor’s choice – ten-year experience with endovascular repair of thoracoabdominal aortic aneurysms: results from 166 consecutive patients. Eur J Vasc Endovasc Surg 2015;49:524–31.
    1. Frazao C, Tavoosi A, Wintersperger BJ, Nguyen ET, Wald RM, Ouzounian M, Hanneman K. Multimodality assessment of thoracic aortic dimensions: comparison of computed tomography angiography, magnetic resonance imaging, and echocardiography measurements. J Thorac Imaging 2020;35:399–406.
    1. Herdman M, Gudex C, Lloyd A, Janssen M, Kind P, Parkin D, et al. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Qual Life Res 2011;20:1727–36.
    1. van Hout B, Janssen MF, Feng YS, Kohlmann T, Busschbach J, Golicki D, et al. Interim scoring for the EQ-5D-5L: mapping the EQ-5D-5L to EQ-5D-3L value sets. Value Health 2012;15:708–15.
    1. Fayers PM, Machin D. Quality of Life: The Assessment, Analysis and Reporting of Patient-reported Outcomes. Chichester: John Wiley & Sons; 2015.
    1. Kirkwood BR, Sterne JAC. Strategies for analysis. Essential Medical Statistics. 2nd edn. Malden, MA: Wiley-Blackwell; 2003:458–69.
    1. Mehta CR, Patel NR. A network algorithm for performing Fisher’s exact test in r × c contingency tables. J Am Stat Assoc 1983;78:427–34.
    1. Rubin DB. Inference and missing data. Biometrika 1976;63:581–92.
    1. Rubin DB. Multiple Imputation for Nonresponse in Surveys. New York, NY: John Wiley and Sons, Inc.; 1987.
    1. Sharples L, Sastry P, Freeman C, Bicknell C, Chiu YD, Vallabhaneni SR et al., on behalf of the ETTAA Collaborative Group. Aneurysm growth, survival, and quality of life in untreated thoracic aortic aneurysms: the effective treatments for thoracic aortic aneurysms study [published online ahead of print November 29 2021]. Eur Heart J 2021.
    1. Rabe-Hesketh S, Skrondal A. Multilevel and Longitudinal Modeling Using Stata. 3rd edn. Vol. 1 and 2. College Station, TX: Stata Press; 2012.
    1. Pinheiro JC, Bates DM. Mixed-Effects Models in S and S-PLUS. New York, NY: Springer; 2000.
    1. Fine JP, Gray RJ. A proportional hazards model for the subdistribution of a competing risk. J Am Stat Assoc 1999;94:496–509.
    1. Rizopoulos D. Joint Models for Longitudinal and Time-to-event Data with Applications in R. New York, NY: Chapman and Hall/CRC; 2012.
    1. Szende A, Janssen B, Cabases J. Self-Reported Population Health: An International Perspective Based on EQ-5D. Dordrecht: Springer; 2014.
    1. Morgan E. National Life Tables: England. URL: (accessed 25 August 2020).
    1. Howard DP, Banerjee A, Fairhead JF, Perkins J, Silver LE, Rothwell PM, Oxford Vascular Study. Population-based study of incidence and outcome of acute aortic dissection and premorbid risk factor control: 10-year results from the Oxford Vascular Study. Circulation 2013;127:2031–7.
    1. Rintoul RC, Ritchie AJ, Edwards JG, Waller DA, Coonar AS, Bennett M, et al. Efficacy and cost of video-assisted thoracoscopic partial pleurectomy versus talc pleurodesis in patients with malignant pleural mesothelioma (MesoVATS): an open-label, randomised, controlled trial. Lancet 2014;384:1118–27.
    1. Sharples L, Everett C, Singh J, Mills C, Spyt T, Abu-Omar Y, et al. Amaze: a double-blind, multicentre randomised controlled trial to investigate the clinical effectiveness and cost-effectiveness of adding an ablation device-based maze procedure as an adjunct to routine cardiac surgery for patients with pre-existing atrial fibrillation. Health Technol Assess 2018;22(19).
    1. Brown LC, Powell JT, Thompson SG, Epstein DM, Sculpher MJ, Greenhalgh RM. The UK EndoVascular Aneurysm Repair (EVAR) trials: randomised trials of EVAR versus standard therapy. Health Technol Assess 2012;16(9).
    1. Warner MA, Divertie MB, Tinker JH. Preoperative cessation of smoking and pulmonary complications in coronary artery bypass patients. Anesthesiology 1984;60:380–3.
    1. Møller AM, Villebro N, Pedersen T, Tønnesen H. Effect of preoperative smoking intervention on postoperative complications: a randomised clinical trial. Lancet 2002;359:114–17.
    1. Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies for causal effects. Biometrika 1983;70:41–55.
    1. Leyrat C, Seaman SR, White IR, et al. Propensity score analysis with partially observed covariates: how should multiple imputation be used? Stat Methods Med Res 2019;28:3–19.
    1. Mitra R, Reiter JP. A comparison of two methods of estimating propensity scores after multiple imputation. Stat Methods Med Res 2016;25:188–204.
    1. Brookhart MA, Wyss R, Layton JB, Stürmer T. Propensity score methods for confounding control in nonexperimental research. Circ Cardiovasc Qual Outcomes 2013;6:604–11.
    1. Williamson EJ, Forbes A. Introduction to propensity scores. Respirology 2014;19:625–35.
    1. Austin PC. Balance diagnostics for comparing the distribution of baseline covariates between treatment groups in propensity-score matched samples. Stat Med 2009;28:3083–107.
    1. Austin PC. An introduction to propensity score methods for reducing the effects of confounding in observational studies. Multivariate Behav Res 2011;46:399–424.
    1. Elze MC, Gregson J, Baber U, Williamson E, Sartori S, Mehran R, et al. Comparison of propensity score methods and covariate adjustment: evaluation in 4 cardiovascular studies. J Am Coll Cardiol 2017;69:345–57.
    1. National Institute for Health and Care Excellence (NICE). Guide to the Methods of Technology Appraisal. London: NICE; 2018.
    1. Manca A, Hawkins N, Sculpher MJ. Estimating mean QALYs in trial-based cost-effectiveness analysis: the importance of controlling for baseline utility. Health Econ 2005;14:487–96.
    1. O’Brien BJ, Drummond MF, Labelle RJ, Willan A. In search of power and significance: issues in the design and analysis of stochastic cost-effectiveness studies in health care. Med Care 1994;32:150–63.
    1. Willan AR, Pinto EM. The value of information and optimal clinical trial design. Stat Med 2005;24:1791–806.
    1. Husereau D, Drummond M, Petrou S, Carswell C, Moher D, Greenberg D, et al. Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement. Value Health 2013;16:e1–5.
    1. Polsky D, Glick H. Costing and cost analysis in randomized controlled trials: caveat emptor. PharmacoEconomics 2009;27:179–88.
    1. Russell LB, Gold MR, Siegel JE, Daniels N, Weinstein MC. The role of cost-effectiveness analysis in health and medicine. Panel on Cost-Effectiveness in Health and Medicine. JAMA 1996;276:1172–7.
    1. Potter S, Davies C, Davies G, Rice C, Hollingworth W. The use of micro-costing in economic analyses of surgical interventions: a systematic review. Health Econ Rev 2020;10:3.
    1. Department of Health and Social Care (DHSC). NHS Reference Costs 2018 to 2019. London: DHSC; 2019.
    1. Curtis L, Burns A. Unit Costs of Health and Social Care 2019. Canterbury: Personal Social Services Research Unit, University of Kent; 2019.
    1. Department of Health and Social Care (DHSC). NHS Reference Costs 2017 to 2018. London: DHSC; 2019.
    1. NHS Blood and Transport (NHSBT). National Health Service Blood and Transport Price List 2018/19. London: NHSBT; 2018.
    1. Department for Business, Energy and Industrial Strategy (BEIS). Department for Business, Energy and Industrial Strategy National Minimum Wage and National Living Wage Rates. London: BEIS; 2020.
    1. Henderson DA, Denison DR. Stepwise regression in social and psychological research. Psychol Rep 1989;64:251–7.
    1. Brady AR, Thompson SG, Fowkes FG, Greenhalgh RM, Powell JT, UK Small Aneurysm Trial Participants. Abdominal aortic aneurysm expansion: risk factors and time intervals for surveillance. Circulation 2004;110:16–21.
    1. Patel R, Sweeting MJ, Powell JT, Greenhalgh RM, EVAR trial investigators. Endovascular versus open repair of abdominal aortic aneurysm in 15-years’ follow-up of the UK endovascular aneurysm repair trial 1 (EVAR trial 1): a randomised controlled trial. Lancet 2016;388:2366–74.
    1. Powell JT, Brown LC, Forbes JF, Fowkes FG, Greenhalgh RM, Ruckley CV, Thompson SG. Final 12-year follow-up of surgery versus surveillance in the UK Small Aneurysm Trial. Br J Surg 2007;94:702–8.
    1. Hudorović N, Vucetic B, Lovricevic I. The evidence for volume-outcome relationships in thoracic aortic surgery. Eur J Cardiothorac Surg 2010;37:248–9.
    1. Karthikesalingam A, Hinchliffe RJ, Loftus IM, Thompson MM, Holt PJ. Volume-outcome relationships in vascular surgery: the current status. J Endovasc Ther 2010;17:356–65.
    1. National Institute For Cardiovascular Outcomes Research. NICOR Database. URL: (accessed 17 May 2021).
    1. Health Quality Improvement Partnership. National Vascular Registry. URL: (accessed 17 May 2021).
    1. van Buuren S, Groothuis-Oudshoorn K. MICE: multivariate imputation by chained equations in R. J Stat Soft 2011;45:1–67.
    1. Little RJA. A test of missing completely at random for multivariate data with missing values. J Am Stat Assoc 1988;83:1198–202.
    1. NHS Employers. NHS Terms and Conditions Pay Poster 2018/19. URL: (accessed October 2021).
    1. National Institute for Health and Care Excellence. A to Z of Drugs | BNF Content Published by NICE. URL: (accessed 11 June 2019).
    1. National Institute for Health and Care Excellence. Perioperative Care in Adults. URL: (accessed October 2021).
    1. Department of Health and Social Care (DHSC). National Schedule of NHS Costs 2018/19. London: DHSC; 2019.
    1. Balami JS, Coughlan D, White PM, McMeekin P, Flynn D, Roffe C, et al. The cost of providing mechanical thrombectomy in the UK NHS: a micro-costing study. Clin Med 2020;20:e40–e45.
    1. Curtis L. Burns A. Unit Costs of Health and Social Care 2015. Canterbury: Personal Social Services Research Unit, University of Kent; 2015.
    1. . National Minimum Wage and National Living Wage Rates. URL: (accessed October 2021).

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