Dissertation - Doctoral Post-thrombotic Syndrome in Pediatrics: Development of a Measurement Index

Author

Maria Laura Avila

Abstract

Objectives: Post-thrombotic syndrome (PTS) is the most common long-term complication of upper and lower extremity (UE/LE) deep vein thrombosis (DVT). The objective of this thesis was to develop an index for diagnosis and severity rating of pediatric PTS.

Methods: Separate sub-indexes were developed for UE and LE. First, a preliminary study was conducted to determine normal values of limb fluid content in children, using bioimpedance spectroscopy (BIS, Study 1); this information was used for item piloting in Study 2. Next, the signs and symptoms (items) to be included in each sub-index were obtained from a survey answered by an international panel of pediatric thrombosis experts and interviews to pediatric patients with PTS; the items were then defined and piloted in children with UE or LE-DVT to test their diagnostic performance and correlation with PTS diagnosis and severity, assessed by a pediatric thrombosis expert (Study 2). Last, the final items of the sub-indexes were voted by the expert panel using a Delphi process; a scoring system was then developed taking into account item importance to health care providers and to patients/parents, using multiple-criteria decision analysis (MCDA); the meaning of the scores was explored by comparing scores with PTS diagnosis and with parental satisfaction/dissatisfaction with the clinical condition of their child (Study 3).

Results: Normal BIS values were obtained from 223 healthy children. Twenty-three experts and 16 patients with PTS identified 34 items, 32 of which fitted our measurement framework and were tested in children with UE-DVT (n=70) or LE-DVT (n=70). Aided by the obtained information on the diagnostic performance of each item, the pediatric thrombosis experts voted to retain 10 and 7 items for the LE and UE sub-indexes, respectively (81% response rate). Item weights were developed using MCDA (122 participants, 82% response rate). Both sub-indexes showed good discriminative ability to differentiate between patients with and without PTS. Higher scores were associated with parental dissatisfaction with the clinical condition of their child.

Conclusion: We present an index for diagnosis and severity rating of pediatric PTS, developed using expert consensus. The tool provides a meaningful score and has proven diagnostic properties.


Supervisor

Brian Feldman