Adjusted Hospital Outcomes of Abdominal Aortic Aneurysm Surgery Reported in the Dutch Surgical Aneurysm Audit

N Lijftogt; A C Vahl; E D Wilschut; B H P Elsman; S Amodio; E W van Zwet; V J Leijdekkers; M W J M Wouters; J F Hamming; Dutch Society of Vascular Surgery, the Steering Committee of the Dutch Surgical Aneurysm Audit, and the Dutch Institute for Clinical Auditing

doi:10.1016/j.ejvs.2016.12.037

Adjusted Hospital Outcomes of Abdominal Aortic Aneurysm Surgery Reported in the Dutch Surgical Aneurysm Audit

Eur J Vasc Endovasc Surg. 2017 Apr;53(4):520-532. doi: 10.1016/j.ejvs.2016.12.037. Epub 2017 Feb 28.

Authors

N Lijftogt¹, A C Vahl², E D Wilschut³, B H P Elsman⁴, S Amodio⁵, E W van Zwet⁵, V J Leijdekkers², M W J M Wouters⁶, J F Hamming³; Dutch Society of Vascular Surgery, the Steering Committee of the Dutch Surgical Aneurysm Audit, and the Dutch Institute for Clinical Auditing

Affiliations

¹ Department of Vascular Surgery, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. Electronic address: [email protected].
² Department of Surgery, OLVG, Oosterpark 9, 1091 AC, Amsterdam, The Netherlands.
³ Department of Vascular Surgery, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
⁴ Department of Vascular Surgery, Deventer Hospital, Nico Bolkesteinlaan 75, 7416 SE, Deventer, The Netherlands.
⁵ Department of Medical Statistics, Leiden University, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands.
⁶ Department of Surgery, Dutch Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands; Scientific Bureau, Dutch Institute for Clinical Auditing, Rijnsburgerweg 10, 2333 AA, Leiden, The Netherlands.

PMID: 28256396
DOI: 10.1016/j.ejvs.2016.12.037

Abstract

Objective/background: The Dutch Surgical Aneurysm Audit (DSAA) is mandatory for all patients with primary abdominal aortic aneurysms (AAAs) in the Netherlands. The aims are to present the observed outcomes of AAA surgery against the predicted outcomes by means of V-POSSUM (Vascular-Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity). Adjusted mortality was calculated by the original and re-estimated V(physiology)-POSSUM for hospital comparisons.

Methods: All patients operated on from January 2013 to December 2014 were included for analysis. Calibration and discrimination of V-POSSUM and V(p)-POSSUM was analysed. Mortality was benchmarked by means of the original V(p)-POSSUM formula and risk-adjusted by the re-estimated V(p)-POSSUM on the DSAA.

Results: In total, 5898 patients were included for analysis: 4579 with elective AAA (EAAA) and 1319 with acute abdominal aortic aneurysm (AAAA), acute symptomatic (SAAA; n = 371) or ruptured (RAAA; n = 948). The percentage of endovascular aneurysm repair (EVAR) varied between hospitals but showed no relation to hospital volume (EAAA: p = .12; AAAA: p = .07). EAAA, SAAA, and RAAA mortality was, respectively, 1.9%, 7.5%, and 28.7%. Elective mortality was 0.9% after EVAR and 5.0% after open surgical repair versus 15.6% and 27.4%, respectively, after AAAA. V-POSSUM overestimated mortality in most EAAA risk groups (p < .01). The discriminative ability of V-POSSUM in EAAA was moderate (C-statistic: .719) and poor for V(p)-POSSUM (C-statistic: .665). V-POSSUM in AAAA repair overestimated in high risk groups, and underestimated in low risk groups (p < .01). The discriminative ability in AAAA of V-POSSUM was moderate (.713) and of V(p)-POSSUM poor (.688). Risk adjustment by the re-estimated V(p)-POSSUM did not have any effect on hospital variation in EAAA but did in AAAA.

Conclusion: Mortality in the DSAA was in line with the literature but is not discriminative for hospital comparisons in EAAA. Adjusting for V(p)-POSSUM, revealed no association between hospital volume and treatment or outcome. Risk adjustment for case mix by V(p)-POSSUM in patients with AAAA has been shown to be important.

Keywords: Abdominal aortic aneurysm; Case-mix adjustment; Clinical audit; Quality of health care.

MeSH terms

Aged
Aged, 80 and over
Aortic Aneurysm, Abdominal / diagnostic imaging
Aortic Aneurysm, Abdominal / mortality
Aortic Aneurysm, Abdominal / surgery*
Aortic Rupture / diagnostic imaging
Aortic Rupture / mortality
Aortic Rupture / surgery*
Benchmarking
Blood Vessel Prosthesis Implantation* / adverse effects
Blood Vessel Prosthesis Implantation* / mortality
Elective Surgical Procedures
Endovascular Procedures* / adverse effects
Endovascular Procedures* / mortality
Female
Hospital Mortality
Hospitals*
Humans
Male
Medical Audit
Netherlands
Quality Indicators, Health Care
Registries
Risk Assessment
Risk Factors
Time Factors
Treatment Outcome