Risk factors for venous obstruction in children with transvenous pacing leads.

To determine the incidence and risk factors for venous obstruction in children with transvenous pacing leads, 63 children were evaluated clinically and echocardiographically. Patients with abnormal clinical and/or echocardiographic findings were further investigated by venography. Thirteen patients (21%) had evidence of venous obstruction. Venography in 11 (2 refused) showed that severity of obstruction (as defined by percentage of luminal narrowing) was complete (100%) in 3, severe (> 90%) in 4, and moderate (60%-90%) in 5 (1 patient having 2 sites of obstruction). Risk factors for obstruction in 55 patients with single implantation procedures (10 with obstruction; 18%) were sought. Total cross-sectional area of lead(s) was indexed to body surface area at implantation (INDEX). Patients with obstruction had a higher mean INDEX (7.6 +/- 1.6 mm2/m2) than patients without obstruction (4.9 +/- 2.0 mm2/m2); P < 0.0002). Receiver-operator characteristic curves showed an INDEX > 6.6 mm2/m2 to best predict obstruction, with a sensitivity of 90% and specificity of 84%. Since pacing is lifelong, sizing of transvenous leads to the child is important to prevent obstruction and preserve venous access.