Background: Repaired coarctation of the aorta is associated with premature atherosclerosis and an increased risk of cardiovascular events even in normotensive subjects. To date clinical risk stratification has focused on brachial blood pressures ignoring the complex pulsatility of the aortic wave form. The aim of this study was to assess components of this pulsatility in a clinical setting and to suggest possible techniques to improve risk stratification.
Methods: This was a prospective study recruiting patients from a tertiary referral centre. Pulse wave morphology was assessed using applanation tonometry. B-mode ultrasound and cardiac magnetic resonance were used to assess carotid intimal-medial thickness and left ventricular mass.
Results: Forty-six subjects with repaired coarctation of the aorta (range 16-62 years; mean 31 years) and 20 matched controls were studied. Baseline brachial systolic and diastolic blood pressures were not statistically different between the 2 groups. Peripheral (62.5 mmHg (11.3) vs. 50.6 mmHg (15.0), p=0.0008) and central (34.5 mmHg (7.7) vs. 28.7 mmHg (4.7), p=0.005) pulse pressures were elevated in the coarctation patients compared to controls. The reflected pressure wave returned to the ascending aorta earlier in the coarctation group (p=0.007) and the tension time index (TTI) was increased (p=0.03). The sub-endocardial viability index (SVI) was reduced in the coarctation subjects (159 (33) vs. 186 (31)%; p=0.009) but there was no differences in central augmentation index (p=0.35).
Conclusions: This study demonstrates that there are patients with repaired coarctation who have an excellent mid-term outcome free from ventricular hypertrophy, carotid intima medial thickening and with relatively preserved vascular reactivity. However even in this "best outcome" cohort there were abnormal vascular characteristics that may predispose to increased cardiovascular risk. Simple non-invasive investigations can more extensively characterise these sub-clinical abnormalities and by utilised in long-term surveillance.
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