Danish Medical Bulletin - No. 4. November 2004. Vol. 51 Page 435.

ABSTRACT OF PhD DISSERTATION

Evaluation of different diagnostic procedures in patients referred for endoscopic retrograde cholangiopancreatography

Alan Patrick Ainsworth

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This PhD dissertation was accepted by the Faculty of Health Sciences, University of Southern Denmark, and defended on October 4, 2004.

Official opponents: Torben Jørgensen, Peter Matzen, and Ove B. Schaffalitzky de Muckadell.

Tutors: Henning Overgaard Nielsen, Claus Peter Hovendal, Michael Bau Mortensen, and Peter Arne Wamberg

Correspondence: Alan Patrick Ainsworth, Rosenlunden 7, 5000 Odense C, Denmark.

Dan Med Bull 2004;51:435.

ABSTRACT

This PhD dissertation consists of three papers and a survey and is based upon a study performed at the Department of Surgery and the Department of Radiology, Vejle Hospital.

Endoscopic retrograde cholangiopancreatography (ERCP) is used for diagnosing diseases in the common bile duct and in the pancreas. However, it is desirable to reduce the number of ERCPs because of the relatively high complication risk. Endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) can be used in the same patients with the advantage of these investigations being a negligible risk of complications. However, in contrast to ERCP it is not possible to perform therapeutic procedures in combination with either of these investigations. Thus, it is still unknown if initial EUS and MRCP will give a substantial reduction in the number of ERCPs being performed.

The aim of this study was to evaluate EUS and MRCP as part of the diagnostic strategy in patients admitted for ERCP. The study comprised 163 patients admitted for elective ERCP in the period 1 June 2000 to 30 June 2002. The sensitivity and specificity for EUS, MRCP, and ERCP were 0.89 and 0.98, 0.90 and 0.92, and 0.90 and 0.94, respectively. Eighty-four (52%) patients were considered to have needed endoscopic therapeutic procedures in combination with ERCP. Thus, the effectiveness of EUS, MRCP and ERCP was 0.45, 0.44, and 0,92, respectively. In total 17 (10%) patients had complications following ERCP. The median hospitalisation after ERCP-related complications was four days (range 3-39 days). No mortality was observed. The total costs of EUS, MRCP, and ERCP were estimated to be 3309 Danish Kroner (DKK), 2914 DKK, and 3907 DKK, respectively. The cost-effectiveness of EUS, MRCP, and ERCP was correspondingly 7353, 6622, and 4246 DKK per fully evaluated and treated patient. A positive Trondsen discriminant function (DF) value had a sensitivity and specificity for predicting obstruction of the bile duct on 0.81 and 0.72, respectively.

It is concluded that initial ERCP was the most cost-effective strategy compared to EUS or MRCP because the majority of patients needed endoscopic therapy. A positive DF could be used to decide if a patient had a high or low probability of needing endoscopic therapy. Thus, low-risk patients should be referred for initial EUS or MRCP, whereas high-risk patients can be referred directly to ERCP.
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