Exercise testing detects hypertension and arch gradients in patients with a good coarctation repair as assessed at rest. The hypertension and arch "obstruction" appear to be related to discrepancies in the growth of the transverse aortic arch proximal to the repair site, rather than a "recoarctation" of the aorta.

Given the temporal association between treatment and improvement, we hypothesize that the markedly elevated white blood cell count has a major role in the cardiopulmonary compromise.

Early initiation of extracorporeal membrane oxygenation to treat acute hypoxemic respiratory failure secondary to massive pulmonary hemorrhage in microscopic polyangiitis in children can be life-saving while awaiting control of the autoimmune disease process by plasmapheresis and immunosuppression.