904-48 Risk Factors for Venous Obstruction in Children with Transvenous Pacing Leads

To determine the incidence and risk factors for venous obstruction (OBST). we prospectively evaluated with echocardiography 63 of 70 eligible children who had transvenous pacing leads placed between 1985 and 1993. The median (range) age at initial implantation was 7.6 yrs (0.7, 16), and 8 patients had subsequent additional implants. OBST was defined as a combination of Doppler flow abnormalities in the SVC or innominate (InnV) vein and a 2D echo appearance of vessel narrowing and/or the clinical appearance of dilated superficial veins. OBST was noted in 13/63 (21%) patients, with location of OBST at the distal subclavian vein in 5, SVC in 4, InnV-SVC junction in 2, and multiple sites in 2. Venography in 11 of these patients (2 refused) showed that the severity of OBST (as defined by % luminal narrowing) was complete (100%) in 3 patients, severe (>90%) in 4, and moderate (60–90%) in 4. Of the 8 patients who had additional implants, 3 (38%) had OBST. Risk factors for OBST in the remaining 55 single implant patients (10 with OBST; 18%) were explored. Patients with vs. without OBST did not differ regarding date or duration of implant, number of leads, lead material or the presence of associated heart defects Or surgery. Patients with OBST were younger at implant (median 5.6 vs. 8.8 yrs; p < 0.05). Total cross-sectional area of lead(s) was related to body surface area at implant (RATIO). Patients with OBST had higher mean RATIO (7.6±1.6mm2/m2) than patients without OBST (4.9±2.0 mm2/m2; p<0.0002). After controlling for RATIO in multiple logistic regression, no other variable predicted OBST. Receiver-operator characteristic curves showed a RATIO of >6.6mm2/m2to best predict OBST, with a sensitivity of 90% and specificity of 84%.ConclusionSince pacing is lifelong, sizing of transvenous leads to the child is important to prevent OBST and preserve venous access