Low weight as an independent risk factor for adverse events during cardiac catheterization of infants.

BACKGROUND: Studies have documented the importance of procedure type and hemodynamic variables on the incidence of procedure related adverse events (AE) after cardiac catheterization. However, little is known about the impact of low weight on the incidence and severity of AE. METHODS: Data were prospectively collected using a multicenter registry (C3PO). Infants <1 year were divided into four weight categories: <2 kg, 2-3 kg, 3-5 kg, ≥5 kg. AE severity was classified as level 1-5 (none, minor, moderate, major, death). RESULTS: Eight centers submitted details on 3,679 cases (34% diagnostic) performed in infants <1 year from 2/07 to 6/10: <2 kg: 57 (1.5%), 2-3 kg: 403 (11%), 3-5 kg: 1,527 (41.5%), ≥5 kg: 1,692 (46%). AE occurred in 20% of cases (<2 kg: 28%, 2-3 kg: 25%, 3-5 kg: 23%, ≥5 kg: 16%) with 41% of all AE being level 3-5 AE. Death occurred more frequently in the <2 kg group (12%), 71% of which were interventional cases. The case-related mortality in all other weight groups was <1%. By multivariable analysis, weight <2 kg, 2-3 kg, and 3-5 kg were independent risk factors for high severity (level 3-5) AE (<2 kg: OR 2, 95%CI 1.1-3.6; 2-3 kg: OR 1.4, 95%CI 1-1.8; 3-5 kg: OR 1.3, 95%CI 1.1-1.5), with similar findings for all AE. Blood transfusions were more common in lower weight categories (<2 kg: 42%, 2-3 kg: 29%, 3-5 kg: 25%, ≥5 kg: 15%, p<0.001). CONCLUSIONS: The risk of AE during cardiac catheterization of infants increases with lower weight. Infants who weigh less than 2 kg have a significantly higher risk of adverse events (most notably death) even after correcting for hemodynamic vulnerability and procedure type risk group.