Secondary erythrocytosis is common in patients with cyanosis secondary to congenital heart disease (CHD) and/or pulmonary hypertension (PH). This compensatory mechanism aims at increasing oxygen delivery to the tissues, but it requires adequate iron stores. Optimal methods of iron supplementation in this setting remain controversial, with fears of excessive erythropoiesis and hyperviscosity symptoms. We describe our experience using intravenous ferrous carboxymaltose.
142 consecutive cyanotic patients were treated over 5.7 years (201 administrations). Mean age was 51.3 ± 17.6 years and 55 (38.7%) were male. Eisenmenger syndrome (ES) was present in 41 (28.8%), other pulmonary arterial hypertension (PAH) related to CHD (PAH-CHD) in 27 (19.0%), cyanotic CHD without PAH in 16 (11.3%) and PH without CHD in 58(40.8%). Baseline haemoglobin (Hb) concentration was 14.6 ± 3.0 g/dL and haematocrit 0.45 ± 0.09. A 500 mg dose of intravenous (IV) iron carboxymaltose was given in 163 (81.1%) of administrations and a 1000 mg dose in 37 (18.4%). A significant improvement in average Hb, haematocrit, ferritin and transferrin saturation was observed after a median follow-up of 100.0 [70.0-161.0] days (p ≤ 0.0001 for all). There were no cases of excessive erythropoiesis resulting in new hyperviscosity symptoms and/or requiring venesection. A minor transient rash was observed in 2 patients and one patient experienced an air embolus causing a transient ischemic attack.
Intravenous ferrous carboxymaltose appears to be safe in iron deficient patients with cyanosis due to CHD and/or PH, as long as care is taken to avoid air emboli. Further randomised studies are needed to confirm the safety and efficacy of intravenous iron in this setting.