Nikhil Bush et al., 2024: Development of a novel CT-based index for predicting the number of extracorporeal shockwave lithotripsy (ESWL) sessions required for successful fragmentation of obstructing pancreatic duct stones
Nikhil Bush 1 , Praneeth Chandragiri 2 , Nitish Ashok Gaurav 2 , Sneh Sonaiya 1 , Ila Lahooti 3 , Anmol Singh 1 , Abhinav Gupta 1 , Elham Afghani 1 , Georgios Papachristou 3 , Mouen A Khashab 1 , Peter J Lee 3 , Rupjyoti Talukdar 2 , Sundeep Lakhtakia 2 , Vikesh K Singh 1 , Samuel Han 3 , Manu Tandan 2 , Venkata S Akshintala 4
1Pancreatitis Center, Division of Gastroenterology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
2Department of Gastroenterology, Asian Institute of Gastroenterology, Hyderabad, India.
3Division of Gastroenterology, Hepatology, and Nutrition, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
4Pancreatitis Center, Division of Gastroenterology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Abstract
Background & aim: Extracorporeal shock wave lithotripsy (ESWL) is used for the treatment of pancreatic duct stones (PDS) in patients with chronic pancreatitis (CP). We aimed to develop a CT based index to predict the required number of ESWL sessions for technical success.
Methods: We retrospectively evaluated patients with PDS secondary to CP who underwent ESWL. Technical success was defined as the complete fragmentation of stones to <3 mm. CT features including PDS size, number, location, and density in Hounsfield units (HU) were noted. We analyzed the relationship between PDS characteristics and the number of ESWL sessions required for technical success. A multiple linear regression model was used to combine size and density into the pancreatic duct stone (PDS) index that was translated into a web-based calculator.
Results: There were 206 subjects (mean age 38.6 ± 13.7 years, 59.2% male) who underwent ESWL. PDS size showed a moderate correlation with the number of ESWL sessions (r = 0.42, p < 0.01). PDS in the head required a fewer number of sessions in comparison to those in the body (1.4 ± 0.6 vs. 1.6 ± 0.7, p = 0.01). There was a strong correlation between PDS density and the number of ESWL sessions (r = 0.617, p-value <0.01). The PDS index {0.3793 + [0.0009755 x PDS density (HU)] + [0.02549 x PDS size (mm)]} could accurately predict the required number of ESWL sessions with an AUC of 0.872 (p < 0.01).
Conclusion: The PDS index is a useful predictor of the number of ESWL sessions needed for technical success that can help in planning and patient counseling.
Pancreatology. 2024 Mar 28:S1424-3903(24)00079-6. doi: 10.1016/j.pan.2024.03.018. Online ahead of print. PMID: 38584052 DOI: 10.1016/j.pan.2024.03.018 FREE ARTICLE
Comments 1
International and national medical guidelines are based on the medical literature. The indications and therapeutic procedures based on these guidelines are probably very similar in different countries. The different healthcare systems and probably the reimbursement conditions have a major influence on the actual application. The present work gives a hint that non-compliance with guidelines is not just an individual decision based on personal preference or ignorance but that it may be dictated by politics and business.
This statement in an international guideline (1) on the treatment of pancreatic stones:
“What is the strategy for the treatment of pancreatic ductal stones?
Statement 4.1. ESWL should be the first-line therapy as nonsurgical
intervention for main pancreatic duct stones in patients
with chronic pancreatitis who do not get adequate pain
relief with conservative management although a stent placement
may be done first to relieve pain.”
seems to be from a different world than what is stated in the present paper:
“PDS is mostly treated with ERCP in the United States while ESWL is used off label restricted to a few centers. Most providers perform ESWL in conjunction with urologists or by temporarily renting lithotripsy equipment in the endoscopy suite. This involves logistical planning including patient scheduling and coordination with radiology and urology services. Moreover, ESWL may need to be followed by ERCP for clearance of residual fragments. Therefore,
information about the probable number of ESWL and ERCP procedures would be helpful in effective preprocedural counseling, planning, and cost estimation.”
As to the way the calculator was designed, I wonder why the authors did not divide the patient groups into a training and a validation set.
The authors point out to the expected limitations of their calculator:
• “About 85% of the cohort was of Asian ethnicity and therefore the results of the study have limited generalizability. … these patients were predominantly idiopathic, whereas alcohol contributed to the majority of the US patients….
• The model also overlooks the effect of body habitus and the generation of ESWL equipment that might influence the number of ESWL sessions as recent studies have shown technical superiority with newer generation of electromagnetic lithotripters.”
1 Kitano M, et al. International consensus guidelines on interventional endoscopy in chronic pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club. Pancreatology. 2020 Sep;20(6):1045-1055. doi: 10.1016/j.pan.2020.05.022. Epub 2020 Jul 10. PMID: 32792253.
Free article
See also: Dalal A, et al. Endosc Int Open. 2024 Feb 28;12(2):E274-E281.
Peter Alken