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IMPACT OF LOCAL ARTERIAL COMPLIANCE AND SHEAR STRESS ON BARORECEPTOR FUNCTION IN CHILDREN WITH REPAIRED COARCTATION OF THE AORTA
E816 JACC March 27, 2012 Volume 59, Issue 13
Congenital Cardiology Solutions IMPACT OF LOCAL ARTERIAL COMPLIANCE AND SHEAR STRESS ON BARORECEPTOR FUNCTION IN CHILDREN WITH REPAIRED COARCTATION OF THE AORTA ACC Moderated Poster Contributions McCormick Place South, Hall A Sunday, March 25, 2012, 11:00 a.m.-Noon
Session Title: Congenital Cardiology Solutions: Interventional Solutions Abstract Category: 27. Congenital Cardiology Solutions: Pediatric Presentation Number: 1136-140 Authors: Damien P. Kenny, Jaimie Polson, Sian Curtis, Ron Hartely-Davies, Massimo Caputo, Rob Martin, John Cockcroft, Julian Paton, Dirk Wilson, Andrew Wolf, Mark Hamilton, Bristol Heart Institute, Bristol, United Kingdom Background: Reduced aortic compliance has been implicated in the ontogeny of post-coarctectomy hypertension. MRI may be used to evaluate local arterial compliance and markers of shear stress that may influence arterial remodeling. This study was designed to measure these variables along the aortic arch and determine potential effects on the aortic baroreceptor and blood pressure control. Methods: Twenty-six children (mean age of 9.2±0.2 years) with early repair of coarctation of the aorta (CoA) and 18 age-matched controls underwent detailed cardiac MRI with evaluation of aortic compliance using simultaneous non-invasive measurement of central blood pressure. Shear stress was calculated using the average flow method. Spontaneous baroreceptor reflex sensitivity (sBRS) was determined using sequence analysis. Results: Central systolic blood pressure was higher in the CoA group (96.7±1.1 vs 92.5±1.8 mmHg, p=0.037) although peripheral ambulatory recordings were comparable. Aortic compliance at the level of the aortic arch was lower in the coarctation group than in controls (1.82±0.18 vs 2.52±0.14 mm2.mmHg-1, p=0.004), although there were no significant differences in compliance in either the ascending or descending aorta. There was no difference in aortic shear stress between the two groups in either the ascending or descending aorta. Although there was no difference in sBRS between the groups, subgroup analysis based on surgical approach demonstrated a relative increase in sBRS in the subclavian flap repair (SFR) group compared to the (end-to-end anastomosis) EEA group. Aortic compliance was also significantly reduced in the SFR group compared to those with EEA (p=0.03). Conclusions: Normotensive children with early effective repair for CoA have reduced aortic compliance at the level of the aortic arch. This is associated with higher central blood pressure although no difference in aortic shear stress. Patients with SFR have reduced aortic compliance compared to patients with EEA and a relative increase in sBRS which may indicate a compensatory increase in baroreceptor sensitivity to maintain blood pressure control in patients at longer term risk for hypertension.
Congenital Cardiology Solutions IMPACT OF LOCAL ARTERIAL COMPLIANCE AND SHEAR STRESS ON BARORECEPTOR FUNCTION IN CHILDREN WITH REPAIRED COARCTATION OF THE AORTA ACC Moderated Poster Contributions McCormick Place South, Hall A Sunday, March 25, 2012, 11:00 a.m.-Noon
Session Title: Congenital Cardiology Solutions: Interventional Solutions Abstract Category: 27. Congenital Cardiology Solutions: Pediatric Presentation Number: 1136-140 Authors: Damien P. Kenny, Jaimie Polson, Sian Curtis, Ron Hartely-Davies, Massimo Caputo, Rob Martin, John Cockcroft, Julian Paton, Dirk Wilson, Andrew Wolf, Mark Hamilton, Bristol Heart Institute, Bristol, United Kingdom Background: Reduced aortic compliance has been implicated in the ontogeny of post-coarctectomy hypertension. MRI may be used to evaluate local arterial compliance and markers of shear stress that may influence arterial remodeling. This study was designed to measure these variables along the aortic arch and determine potential effects on the aortic baroreceptor and blood pressure control. Methods: Twenty-six children (mean age of 9.2±0.2 years) with early repair of coarctation of the aorta (CoA) and 18 age-matched controls underwent detailed cardiac MRI with evaluation of aortic compliance using simultaneous non-invasive measurement of central blood pressure. Shear stress was calculated using the average flow method. Spontaneous baroreceptor reflex sensitivity (sBRS) was determined using sequence analysis. Results: Central systolic blood pressure was higher in the CoA group (96.7±1.1 vs 92.5±1.8 mmHg, p=0.037) although peripheral ambulatory recordings were comparable. Aortic compliance at the level of the aortic arch was lower in the coarctation group than in controls (1.82±0.18 vs 2.52±0.14 mm2.mmHg-1, p=0.004), although there were no significant differences in compliance in either the ascending or descending aorta. There was no difference in aortic shear stress between the two groups in either the ascending or descending aorta. Although there was no difference in sBRS between the groups, subgroup analysis based on surgical approach demonstrated a relative increase in sBRS in the subclavian flap repair (SFR) group compared to the (end-to-end anastomosis) EEA group. Aortic compliance was also significantly reduced in the SFR group compared to those with EEA (p=0.03). Conclusions: Normotensive children with early effective repair for CoA have reduced aortic compliance at the level of the aortic arch. This is associated with higher central blood pressure although no difference in aortic shear stress. Patients with SFR have reduced aortic compliance compared to patients with EEA and a relative increase in sBRS which may indicate a compensatory increase in baroreceptor sensitivity to maintain blood pressure control in patients at longer term risk for hypertension.