P120. Effect of Collagen Cross-linking Therapy on Ascending Aortic Aneurysmal Tissue: An ex vivo Randomized Study
Presented During: POD Abstracts (Available for viewing in the exhibit hall for the duration of the meeting)
Cleveland Clinic
Cleveland, OH
United States - Contact Me
Richard Ramsingh MD is a Cardiac Surgery Research Fellow under the mentorship of the distinguished Dr. Faisal Bakaeen at Cleveland Clinic. After graduating with honours from The University of the West Indies in Trinidad and Tobago, he worked under Dr. Giovanni Teodori as a cardiac surgery resident before migrating to the United States to seek formal training. His research primarily involved cardiac surgery outcomes in Trinidad, including the development of a blueprint for cardiac surgery programs in small island nations.
Currently, his research interests lie in advancing aortic aneurysm therapies, improving reoperative surgery outcomes, and enhancing patient education. In the future, he aspires to increase the adoption of advanced coronary surgery techniques through educational initiatives. Richard enjoys basketball, hiking with his wife and Shiba Inu, and continuously learning about cardiac surgery to inform his practice.
Thursday, April 25, 2024: 5:38 PM - 7:00 PM
Sheraton Times Square
Room: Central Park
Description
Objective: Ultraviolet light (UV) irradiation in the presence of riboflavin is known to enhance mechanical strength and stiffness of collagen-based tissues through photochemical crosslinking of collagen fibers. We investigated the effect of combined riboflavin treatment and UV irradiation on both delamination and biaxial mechanical parameters in ex vivo human ascending aortic aneurysmal tissue.
Methods: Aortic specimens from patients undergoing ascending aortic replacement were collected for mechanical testing. Each specimen provided two sample sets from proximal and distal regions, which were randomized to treatment or control groups in a 1:1 ratio. Treated samples were soaked with 0.1% riboflavin solution for 30 minutes and then exposed to an irradiance of 45 mW/cm2 at 365nm for 10 minutes. Delamination testing simulates dissection and assesses the delamination strength of the tissue. Biaxial mechanical testing assesses stretch, stiffness, stress, or strain-energy density of the tissue. Linear mixed-effect models were used to assess the effect of treatment on mechanical outcomes. Correlation of determination (R2) was used to evaluate the relationship between delamination strength and biaxial mechanical outcomes. Gradient boosting models were implemented to assess the independent effect of treatment on mechanical outcomes.
Results: From 8/2023 to 11/2023, 27 adults were enrolled; 19 patients (mean age±SD: 63.7±11.1, 17 males) yielded 114 samples with complete biomechanical outcomes; delamination testing (76 samples [38 circumferential, 38 longitudinal], 66%) and biaxial mechanical testing (38 samples, 33%). There was no observed difference between the treated and control tissue with respect to delamination strength (β=0.8, P=.8), stretch (β=0.01, P=.1), stiffness (β=319, P=.2), stress (β=12, P=.2) or strain-energy density (β=0.8, P=.7). After adjustment for tissue and patient characteristics, we found several significant associations; delamination strength was inversely associated with age (β=-0.7, P=.01); biaxial stretch was lower in the longitudinal direction (β=-0.05, P<.001) and inversely associated with age (β=-0.006, P<.001); biaxial stiffness was lower in the longitudinal direction (β=-916, P<.001) and in the distal region (β=616, P<.001); biaxial strain-energy density was higher in the proximal region (β=7.1, P<.001) and inversely associated with age (β=-1.5, P<.001); biaxial stress was lower in the longitudinal direction (β=-45, P<.001), higher in the proximal region (β=57, P<.001), and inversely associated with age (β=-3.8, P<.01). Delamination strength was most well correlated with stretch in the longitudinal direction (R2=0.56 treatment, R2=0.11 control) (Figure 1A) and strain-energy density (R2=0.39 treatment, R2=0.11 control) (Figure 1B). Gradient boosting models were underpowered but demonstrated similar non-linear relationships, with age being the predominant covariate driving mechanical outcomes.
Conclusions: We did not observe a treatment effect on ascending aortic aneurysmal tissue using UV irradiation and riboflavin. Predictors of tissue mechanics were age, orientation, and region. Correlation between delamination strength and strain-energy density suggests that tissue with greater efficiency in storing energy requires more force to propagate a dissection plane. This finding, which has not been previously demonstrated, may be useful when evaluating the effectiveness of tissue-modifying therapies.
Authors
Richard Ramsingh (1), Benjamin Kramer (1), Abigail Snyder (1), Aaron Tipton (1), Erik Waldorff (1), Callan Gillespie (1), Samar Tarraf (2), Robb Colbrunn (1), Betty Hamilton (1), William Dupps Jr. (1), Marijan Kopravanac (1), Patrick Vargo (1), Eric Roselli (1), Faisal Bakaeen (1)
Institutions
(1) Cleveland Clinic, Cleveland, OH, (2) Northeastern Univeristy, Boston, MA
Methods: Aortic specimens from patients undergoing ascending aortic replacement were collected for mechanical testing. Each specimen provided two sample sets from proximal and distal regions, which were randomized to treatment or control groups in a 1:1 ratio. Treated samples were soaked with 0.1% riboflavin solution for 30 minutes and then exposed to an irradiance of 45 mW/cm2 at 365nm for 10 minutes. Delamination testing simulates dissection and assesses the delamination strength of the tissue. Biaxial mechanical testing assesses stretch, stiffness, stress, or strain-energy density of the tissue. Linear mixed-effect models were used to assess the effect of treatment on mechanical outcomes. Correlation of determination (R2) was used to evaluate the relationship between delamination strength and biaxial mechanical outcomes. Gradient boosting models were implemented to assess the independent effect of treatment on mechanical outcomes.
Results: From 8/2023 to 11/2023, 27 adults were enrolled; 19 patients (mean age±SD: 63.7±11.1, 17 males) yielded 114 samples with complete biomechanical outcomes; delamination testing (76 samples [38 circumferential, 38 longitudinal], 66%) and biaxial mechanical testing (38 samples, 33%). There was no observed difference between the treated and control tissue with respect to delamination strength (β=0.8, P=.8), stretch (β=0.01, P=.1), stiffness (β=319, P=.2), stress (β=12, P=.2) or strain-energy density (β=0.8, P=.7). After adjustment for tissue and patient characteristics, we found several significant associations; delamination strength was inversely associated with age (β=-0.7, P=.01); biaxial stretch was lower in the longitudinal direction (β=-0.05, P<.001) and inversely associated with age (β=-0.006, P<.001); biaxial stiffness was lower in the longitudinal direction (β=-916, P<.001) and in the distal region (β=616, P<.001); biaxial strain-energy density was higher in the proximal region (β=7.1, P<.001) and inversely associated with age (β=-1.5, P<.001); biaxial stress was lower in the longitudinal direction (β=-45, P<.001), higher in the proximal region (β=57, P<.001), and inversely associated with age (β=-3.8, P<.01). Delamination strength was most well correlated with stretch in the longitudinal direction (R2=0.56 treatment, R2=0.11 control) (Figure 1A) and strain-energy density (R2=0.39 treatment, R2=0.11 control) (Figure 1B). Gradient boosting models were underpowered but demonstrated similar non-linear relationships, with age being the predominant covariate driving mechanical outcomes.
Conclusions: We did not observe a treatment effect on ascending aortic aneurysmal tissue using UV irradiation and riboflavin. Predictors of tissue mechanics were age, orientation, and region. Correlation between delamination strength and strain-energy density suggests that tissue with greater efficiency in storing energy requires more force to propagate a dissection plane. This finding, which has not been previously demonstrated, may be useful when evaluating the effectiveness of tissue-modifying therapies.
Authors
Richard Ramsingh (1), Benjamin Kramer (1), Abigail Snyder (1), Aaron Tipton (1), Erik Waldorff (1), Callan Gillespie (1), Samar Tarraf (2), Robb Colbrunn (1), Betty Hamilton (1), William Dupps Jr. (1), Marijan Kopravanac (1), Patrick Vargo (1), Eric Roselli (1), Faisal Bakaeen (1)
Institutions
(1) Cleveland Clinic, Cleveland, OH, (2) Northeastern Univeristy, Boston, MA
Presentation Duration
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