P Du1, A Hameed2, T R Angeli1, C Lahr3, T L Abell4, L K Cheng1,5, G O'Grady1,6. 1. Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand. 2. Division of Surgery, Westmead Hospital, Sydney, NSW, Australia. 3. Department of Surgery, Mississippi Medical Center, Jackson, MI, USA. 4. Department of Gastroenterology, University of Louisville, Louisville, KY, USA. 5. Department of Surgery, Vanderbilt University, Nashville, TN, USA. 6. Department of Surgery, University of Auckland, Auckland, New Zealand.
Abstract
BACKGROUND: Gastric contractions are coordinated by slow waves, generated by interstitial cells of Cajal (ICC). Gastric surgery affects slow wave conduction, potentially contributing to postoperative gastric dysfunction. However, the impact of gastric cuts on slow waves has not been comprehensively evaluated. This study aimed to define consequences of surgical excisions on gastric slow waves by applying high-resolution (HR) electrical mapping and in silico modeling. METHODS: Patients undergoing gastric stimulator implantation (n = 10) underwent full-thickness stapled excisions (25 × 15 mm, distal corpus) for histological evaluation, enabling HR mapping (256 electrodes; 36 cm(2) ) over and adjacent to excisions. A biophysically based in silico model of bidirectionally coupled ICC networks was developed and applied to investigate the underlying conduction mechanisms and importance of excision orientation. KEY RESULTS: Normal gastric slow waves propagated aborally (3.0 ± 0.2 cpm). Excisions induced complete conduction block and wavelets that rotated around blocks, then propagated rapidly circumferentially distal to the blocks (8.5 ± 1.2 vs normal 3.6 ± 0.4 mm/s; p < 0.01). This 'conduction anisotropy' homeostatically restored antegrade propagating gastric wavefronts distal to excisions. Excisions were associated with complex dysrhythmias in five patients: retrograde propagation (3/10), ectopics (3/10), functional blocks (2/10), and collisions (1/10). Simulations demonstrated conduction anisotropy emerged from bidirectional coupling within ICC layers and showed transverse incision length and orientation correlated with the degree of conduction distortion. CONCLUSIONS & INFERENCES: Orienting incisions in the longitudinal gastric axis causes least disruption to electrical conduction and motility. However, if transverse incisions are made, a homeostatic mechanism of gastric conduction anisotropy compensates by restoring aborally propagating wavefronts. Complex dysrhythmias accompanying excisions could modify postoperative recovery in susceptible patients.
BACKGROUND: Gastric contractions are coordinated by slow waves, generated by interstitial cells of Cajal (ICC). Gastric surgery affects slow wave conduction, potentially contributing to postoperative gastric dysfunction. However, the impact of gastric cuts on slow waves has not been comprehensively evaluated. This study aimed to define consequences of surgical excisions on gastric slow waves by applying high-resolution (HR) electrical mapping and in silico modeling. METHODS:Patients undergoing gastric stimulator implantation (n = 10) underwent full-thickness stapled excisions (25 × 15 mm, distal corpus) for histological evaluation, enabling HR mapping (256 electrodes; 36 cm(2) ) over and adjacent to excisions. A biophysically based in silico model of bidirectionally coupled ICC networks was developed and applied to investigate the underlying conduction mechanisms and importance of excision orientation. KEY RESULTS: Normal gastric slow waves propagated aborally (3.0 ± 0.2 cpm). Excisions induced complete conduction block and wavelets that rotated around blocks, then propagated rapidly circumferentially distal to the blocks (8.5 ± 1.2 vs normal 3.6 ± 0.4 mm/s; p < 0.01). This 'conduction anisotropy' homeostatically restored antegrade propagating gastric wavefronts distal to excisions. Excisions were associated with complex dysrhythmias in five patients: retrograde propagation (3/10), ectopics (3/10), functional blocks (2/10), and collisions (1/10). Simulations demonstrated conduction anisotropy emerged from bidirectional coupling within ICC layers and showed transverse incision length and orientation correlated with the degree of conduction distortion. CONCLUSIONS & INFERENCES: Orienting incisions in the longitudinal gastric axis causes least disruption to electrical conduction and motility. However, if transverse incisions are made, a homeostatic mechanism of gastric conduction anisotropy compensates by restoring aborally propagating wavefronts. Complex dysrhythmias accompanying excisions could modify postoperative recovery in susceptible patients.
Authors: Jonathan C Erickson; Greg O'Grady; Peng Du; John U Egbuji; Andrew J Pullan; Leo K Cheng Journal: Ann Biomed Eng Date: 2010-10-07 Impact factor: 3.934
Authors: Niranchan Paskaranandavadivel; Gregory O'Grady; Peng Du; Andrew J Pullan; Leo K Cheng Journal: IEEE Trans Biomed Eng Date: 2011-12-26 Impact factor: 4.538
Authors: G O'Grady; P Du; N Paskaranandavadivel; T R Angeli; W J E P Lammers; S J Asirvatham; J A Windsor; G Farrugia; A J Pullan; L K Cheng Journal: Neurogastroenterol Motil Date: 2012-07 Impact factor: 3.598
Authors: G O'Grady; J U Egbuji; P Du; W J E P Lammers; L K Cheng; J A Windsor; A J Pullan Journal: Neurogastroenterol Motil Date: 2011-06-30 Impact factor: 3.598
Authors: Madhusudan Grover; Gianrico Farrugia; Matthew S Lurken; Cheryl E Bernard; Maria Simonetta Faussone-Pellegrini; Thomas C Smyrk; Henry P Parkman; Thomas L Abell; William J Snape; William L Hasler; Aynur Ünalp-Arida; Linda Nguyen; Kenneth L Koch; Jorges Calles; Linda Lee; James Tonascia; Frank A Hamilton; Pankaj J Pasricha Journal: Gastroenterology Date: 2011-02-04 Impact factor: 22.682
Authors: R Vather; G O'Grady; A Y Lin; P Du; C I Wells; D Rowbotham; J Arkwright; L K Cheng; P G Dinning; I P Bissett Journal: Br J Surg Date: 2018-04-14 Impact factor: 6.939
Authors: Terence P Mayne; Niranchan Paskaranandavadivel; Jonathan C Erickson; Gregory OGrady; Leo K Cheng; Timothy R Angeli Journal: IEEE Trans Biomed Eng Date: 2018-02 Impact factor: 4.538
Authors: T R Angeli; P Du; N Paskaranandavadivel; S Sathar; A Hall; S J Asirvatham; G Farrugia; J A Windsor; L K Cheng; G O'Grady Journal: Neurogastroenterol Motil Date: 2016-12-29 Impact factor: 3.598
Authors: Rachel Berry; Niranchan Paskaranandavadivel; Peng Du; Mark L Trew; Gregory O'Grady; John A Windsor; Leo K Cheng Journal: Surg Endosc Date: 2016-04-29 Impact factor: 4.584
Authors: Zahra Aghababaie; Niranchan Paskaranandavadivel; Satya Amirapu; Chih-Hsiang Alexander Chan; Peng Du; Samuel J Asirvatham; Gianrico Farrugia; Arthur Beyder; Gregory O'Grady; Leo K Cheng; Timothy R Angeli-Gordon Journal: Am J Physiol Gastrointest Liver Physiol Date: 2021-01-20 Impact factor: 4.052