Pacemaker-Lead Endocarditis

ABSTRACT & COMMENTARY

Synopsis: Transesophageal echo for diagnosis and to guide management is quite important and should be adopted by all physicians dealing with a possible lead infection.

Source: Klug D, et al. Circulation 1997;95:2098-2107.
Endocarditis is a rare but devastating complication of transvenous pacemakers. A group from France has reported on their experience with 52 patients hospitalized for this problem over four years. Klug and colleagues used a set of specific criteria for making the diagnosis. Major diagnostic criteria included positive blood cultures with typical organisms without another primary focus for infection and echocardiographic evidence of an abscess or vegetation on or adjacent to the pacemaker lead. Minor criteria included fever, vascular or immunologic phenomena, or positive blood cultures with organisms unusual for device-related infections.

A standard investigative protocol was employed that included blood cultures, transthoracic and transesophageal echocardiography, and ventilation perfusion scintigraphy. Once a lead-related infection was found, the lead was moved either by direct percutaneous extraction or by an open chest surgical approach. Presentation was early post placement (six weeks) in 14 patients and chronic in 38. In the early group, 65% met criteria for endocarditis, whereas 95% in the chronic group did. First implantations were the more common preceding procedure in both groups, but pacemaker exteriorization was also frequent in the chronic group; the average number of preceding procedures was two in this group. Fever was the most common and earliest presenting symptom in both groups (93% acute, 84% chronic). Local symptoms were next most common (43% and 55%). Pulmonary abnormalities were frequent, especially in the chronic group (45%), and included pleural effusion, consolidation, and abscess. Pulmonary emboli occurred in three acute patients and in 13 chronic patients (34%) before lead extraction. Staphylococcus aureus was the most common organism in the acute group (50%) as was Staphylococcus epidermidis in the chronic group (75%). Transthoracic echo (TTE) disclosed vegetation in only one acute patient, but transesophageal echo (TEE) was positive in 92%, some of whom had a sleeve-like appearing vegetation on the pacemaker lead. More patients had a positive TTE in the chronic group (30%), but the sensitivity of TEE was superior (95%). Percutaneous lead removal was the primary mode of therapy, and 30% demonstrated pulmonary scintigraphic signs of vegetation migration afterward. However, only one patient developed significant septic pulmonary emboli, and there were no peri-procedure deaths. One-fifth of the patients underwent surgical removal, and half of these patients also had tricuspid valve resection. Mortality was 8% in the hospital and 27% overall after a 20-month follow-up. Klug et al emphasize that pacemaker lead endocarditis should be suspected if fever, complications, or pulmonary lesions occur after insertion, and TEE is the diagnostic technique of choice.

COMMENT BY JOHN P. DiMARCO, MD, PhD

Device-related infections continue to be a major complication of pacemaker implantation and replacement. These infections may present in a number of ways such as superficial wound infections, early and late purulent fluid collections in the pocket, chronic erosions, and lead infections without obvious abnormalities in the pocket. Management of these infections is often difficult. Superficial infections may not contaminate the pocket or leads and may respond to antibiotic therapy. Erosions may occasionally be managed locally, but lead infection is a distinct possibility. Purulent pocket and lead infections are true emergencies and can be life-threatening. Removal of newly implanted leads is usually quite easy, but emboli from vegetations on the leads may occur even in this setting. Infections related to chronic leads are more difficult since special techniques are usually recommended for complete lead removal and both surgical removal and percutaneous extraction techniques have significant potential for complications. In this paper, Klug et al provide us with a good clinical description of the spectrum of pacemaker lead-related infections, outline a diagnostic approach for evaluating possible infections, and provide insights into when to choose surgical removal vs. direct percutaneous extraction.

The authors’ use of (TEE) for diagnosis and to guide management is quite important and should be adopted by all physicians dealing with a possible lead infection. As their data showed, the TEE can clinch the diagnosis in equivocal cases. The results are also of value in planning a strategy for lead extraction. They recommend that direct surgery be used for lead removal whenever vegetations of greater than 10 mm are detected to minimize the risk of dislodging septic emboli into the pulmonary circulation.

The best therapy for pacemaker-related infections is prevention. Careful surgical technique is critical and is particularly important for second procedures involving chronically implanted leads. Dealing with the infections that occur requires a systematic approach and should probably be done in the experienced center.