Intimal thickening at coronary bifurcations in pediatric heart transplant recipients
Stephanie L Duncombe1,2, Martin C K Hosking1,2, Anita T Coté3
1Children's Heart Centre, BC Children's Hospital, Vancouver, BC, Canada.
Insights
Intimal thickening, a precursor to atherosclerosis, is common in pediatric heart transplant recipients, particularly in the left coronary system. Side branch size influences its development, suggesting a role for shear stress.
Area of Science:
- Cardiovascular Research
- Pediatric Cardiology
- Transplant Medicine
Background:
- Heart transplant recipients face elevated risks of atherosclerosis and cardiac allograft vasculopathy.
- Intimal thickening is an early indicator of these conditions.
Purpose of the Study:
- To investigate the presence, extent, and anatomical features of intimal thickness at coronary bifurcations in pediatric heart transplant recipients.
- To utilize optical coherence tomography (OCT) for detailed analysis.
Main Methods:
- OCT imaging was employed during routine cardiac catheterization in pediatric transplant recipients.
- Intimal thickness was quantified at coronary bifurcations, with specific criteria for definition.
- 153 bifurcations in 31 children were analyzed.
Main Results:
- Intimal thickening was frequently observed in the left coronary system (22/67 bifurcations) but rare in the right (2/86 bifurcations).
- A significant positive association was found between side branch size and contralateral intimal thickening at bifurcations.
- The findings indicate intimal thickening is present in the left coronary system of many pediatric recipients.
Conclusions:
- Coronary intimal thickening is prevalent in the left coronary system of pediatric heart transplant recipients.
- The correlation with side branch size suggests that hemodynamic factors like low and oscillating shear stress contribute to intimal thickening development at bifurcations.
Abstract:
Heart transplant recipients are at increased risk for atherosclerosis and cardiac allograft vasculopathy, both initially presenting as intimal thickening. We aimed to determine the presence, extent, and anatomical characteristics of intimal thickness at coronary bifurcations in children using OCT. We measured the intimal thickness of coronary arteries in pediatric transplant recipients using OCT during routine cardiac catheterization. Intimal thickening was defined as (i) a percent change in contralateral intimal thickness greater than 50% when comparing the thickness at the bifurcation to the baseline thickness, and (ii) greater than 0.1 mm. We evaluated 153 unique coronary bifurcations in 31 children (58% boys, median 12.7 years). Intimal thickening was almost exclusively observed in the left coronary system (22 of 67 bifurcations) and rare in the right coronary system (2 of 86 bifurcations; P < .001). There was a positive association between the relative size of the side branch and contralateral intimal thickening at coronary bifurcations (P = .009). Intimal thickening at coronary bifurcations is already present in the left coronary system in many pediatric transplant recipients. The correlation between intimal thickening and side branch size suggests that low shear stress and oscillating shear stress may have an important role in the development of intimal thickening at coronary bifurcations.
