Lead-related infective endocarditis: factors influencing the formation of large vegetations

The presence of intracardiac lead vegetations (ILV) is one of the important criteria for diagnosis of lead-related infective endocarditis (LRIE). The objective of the present study was to evaluate risk factors of ILV and their impact on vegetation size.

Clinical data of 500 patients with LRIE undergoing transvenous lead extraction in 2006-15 were retrospectively analysed. The study population consisted of 352 patients with the presence of vegetations (giant, >3 cm; large, 2.0-2.9 cm; moderate-sized, 1.0-1.9 cm; and small, <1 cm) and 148 patients without ILV. We identified risk factors for vegetation occurrence and ILV size. Intracardiac lead vegetations were found more frequently in younger patients (P < 0.05), slightly more often in women (P = 0.084), and less commonly in patients with atrial fibrillation (P < 0.05). Intracardiac lead vegetation occurred significantly more frequently in patients with intracardiac lead abrasion (OR 2.373; 95% CI [1.497-3.765]; P < 0.001) and much less frequently in the concomitant presence of pocket infection (PI) (OR 0.127; 95% CI [0.074-0.218]; P < 0.00). Large vegetations were significantly more common in patients with renal failure (RF) (P < 0.001), heart failure (P < 0.001), implantable cardioverter defibrillator (P < 0.05), and loops of the leads (P < 0.001).

Intracardiac lead abrasion is one of the most common factors influencing the occurrence of ILV. Metabolic disorders in patients with RF, heart failure, defibrillation leads, and loops of the leads were found to contribute to the formation of large vegetations. In LRIE patients, ILVs were less frequently detected in the presence of concomitant PI, indicating a different mechanism of LRIE development in patients with and without vegetations.