Different Patterns of Cerebral and Muscular Tissue Oxygenation 10 Years After Coarctation Repair

Abstract

The purpose of this study was to assess whether the lower exercise tolerance in children after coarctation repair is associated with alterations in peripheral tissue oxygenation during exercise. A total of 16 children after coarctation repair and 20 healthy control subjects performed an incremental ramp exercise test to exhaustion. Cerebral and locomotor muscle oxygenation were measured by means of near infrared spectroscopy. The responses of cerebral and muscle tissue oxygenation index (cTOI, mTOI), oxygenated (O 2 Hb), and deoxygenated hemoglobin (HHb) as a function of work rate were compared. Correlations between residual continuous wave Doppler gradients at rest, arm-leg blood pressure difference and local oxygenation responses were evaluated. Age, length, and weight was similar in both groups. Patients with aortic coarctation had lower peak power output (Ppeak) (72.3 ± 20.2% vs. 106 ± 18.7%, P < 0.001), VO 2 peak/kg (37.3 ± 9.1 vs. 44.2 ± 7.6 ml/kg, P = 0.019) and %VO 2 peak/kg (85.7 ± 21.9% vs. 112.1 ± 15.5%, P < 0.001). Cerebral O 2 Hb and HHb had a lower increase in patients vs. controls during exercise, with significant differences from 60 to 90% Ppeak (O 2 Hb) and 70% to 100% Ppeak (HHb). Muscle TOI was significantly lower in patients from 10 to 70% Ppeak and muscle HHb was significantly higher in patients vs. controls from 20 to 80% Ppeak. Muscle O 2 Hb was not different between both groups. There was a significant correlation between residual resting blood pressure gradient and muscle HHb/ P at 10-20W and 20-30W (r = 0.40, P = 0.039 and r = 0.43, P = 0.034). Children after coarctation repair have different oxygenation responses at muscular and cerebral level. This reflects a different balance between O 2 supply to O 2 demand which might contribute to the reduced exercise tolerance in this patient population.

Oxigenación de músculos respiratorios y locomotores durante el test cardiopulmonar en pacientes con circulación de Fontan: serie de casos

“…No obstante, la estrategia utilizada por los participantes de este estudio podría explicarse como un mecanismo compensatorio tras la ausencia de un ventrículo sub-pulmonar que, a través de la contracción de la musculatura respiratoria provocaría mayores gradientes de presión pleural negativa a expensas de incrementos en Vc durante el ejercicio, elevando el llenado univentricular para optimizar la entrega de sangre a los tejidos en cada respiración 27 . En los últimos años ha existido creciente evidencia sobre la evaluación de NIRS en pacientes pediátricos con cardiopatías congénitas 12,28 . Según nuestro conocimiento, este es el primer reporte que evalúa en PCF la oxigenación muscular respiratoria y locomotora de manera sincrónica en población chilena, entregando resultados interesantes respecto a la necesidad de valorar la oxigenación muscular respiratoria y locomotora como un componente objetivo para la prescripción individualizada en la reha-bilitación cardíaca sugerida para los PCF 6,22 .…”