Cardiac device infections (CDIs) represent a serious complication after the implantation of pacemakers and defibrillators. In addition to antimicrobials, complete hardware removal, mostly with percutaneous lead extraction (PLE), is necessary to limit recurrences. However, CDI diagnosis is often difficult and is sometimes delayed, and scarce data exist on how the timing of PLE may affect clinical outcomes. In this study, the in-hospital outcomes of 52 consecutive patients with CDIs who underwent PLE were retrospectively analyze. Co-morbidities such as diabetes mellitus, congestive heart failure, renal insufficiency, and end-stage renal disease were highly prevalent in the study cohort. Patients were divided into group A (bacteremia or device endocarditis) and group B (localized pocket infection). In-hospital mortality was 29% in group A and 5% in group B (p = 0.02) and was due mostly to sepsis. Hospital stays were shorter in group B patients (5.7 vs 21.7 days, p <0.001). Presentation with hypotension was more commonly observed in group A patients and was associated with higher in-hospital mortality, whereas pocket findings correlated with better survival. Postoperative courses after PLE were uneventful in most patients, and no fatal complications were observed. PLE was performed significantly earlier in group B patients (hospitalization day 1.3 vs 7.6, p <0.001). PLE performed within 3 hospitalization days was associated with lower in-hospital mortality (p = 0.01). In conclusion, PLE performed within 3 days from admission is associated with shorter hospitalization and better survival. A timely diagnosis is crucial, particularly in the absence of local findings, because early treatment with PLE is likely to prevent the catastrophic outcomes of unrelenting CDIs.
Limited data exist to date on the relation between clinical presentation of cardiac device infections (CDIs) and outcomes, in particular how the timing of intervention may affect outcomes in patients with CDIs. We aimed to analyze retrospectively the in-hospital outcomes of a single-center population referred for percutaneous lead extraction (PLE) for CDI. In particular, we investigated the relation among clinical presentation, length of hospital stay, treatment, and final outcomes, including death. The hypothesis was that earlier diagnosis and definitive treatment with PLE would be associated with lower mortality rates.
Methods
The study was approved by the Washington Hospital Center Institutional Review Board. Patient data were obtained by review of medical records of consecutive patients who underwent PLE with the indication of CDI at our center from January 2009 to May 2011. Patients who were scheduled for PLE and never underwent the procedure for any reason (including death before the procedure) were excluded from the analysis. Clinical features at presentation, laboratory and echocardiographic data, and PLE procedural as well as in-hospital outcomes were collected. Washington Hospital Center is one of the main referral centers for PLE in the areas of Washington, northern Virginia, and southern Maryland. Patients were transferred from nearby institutions, referred for hospital admission from cardiologists’ offices, or presented to the local emergency department with suspected CDI. CDI was suspected in the event of local findings at the generator site and/or in case of presentation with fever or other constitutional symptoms, with or without bacteremia. The diagnosis of bacteremia was made in the presence of ≥2 sets of positive blood cultures. All patients with bacteremia underwent transthoracic echocardiography, and if the results were negative, they underwent transesophageal echocardiography to exclude cardiac vegetation. Cultures of the generator pocket and lead tip were also obtained at the time of PLE.
For the purpose of the study, patients were divided in 2 groups according to clinical scenario (group A, bacteremia or endocarditis; group B, localized pocket infection, no bacteremia). Infectious disease consultation was obtained in all patients for advice regarding the duration and modality of administration of antimicrobial therapy as well as to discuss the therapeutic strategy.
Written informed consent for PLE was discussed with patients and/or family members. PLE was performed by 2 operators with training in PLE (E.V.P. and J.A.M.). The procedure was performed in the electrophysiology laboratory under moderate sedation with on-site, immediately available cardiothoracic surgery backup only if lead explantation was anticipated (using simple traction technique, without the need for specialized extraction materials) and with leads that were <1 year old. Conversely, PLE was carried out in the operating room under general anesthesia with on-site, immediately available cardiothoracic surgery backup for all leads >1 year old or whenever the need for traction devices (i.e., locking stylets) or mechanical or laser sheaths was anticipated. Removal of all targeted leads in their entirety from the vascular space was considered complete procedural success. Retention of a small portion of the lead was considered incomplete extraction. Inability to achieve either of these results, or the development of severe disabling or fatal complications related to PLE, was considered procedural failure. All intraprocedural or postprocedural complications were recorded and classified according to published criteria.
Student’s t tests were used to compare continuous variables, while Fisher’s exact tests and chi-square tests were used to compare categorical variables, as appropriate. A statistically significant p value of <0.05 (2-sided test) was chosen.
Data on survival at 30 days were obtained by review of inpatient and/or outpatient medical records. A Kaplan-Meier survival curve was constructed with a log-rank Cox-Mantel test to compare survival in the 2 groups.
Results
Baseline characteristics of the 2 groups are listed in Table 1 . Overall, there was a high prevalence of co-morbidities such as diabetes mellitus (48%), coronary disease (60%), congestive heart failure (63%), renal insufficiency (40% stages 2 to 4 according to the National Kidney Foundation classification ), and end-stage renal disease on hemodialysis (21%). There were no statistically significant differences in terms of co-morbidities between the 2 groups, with the exception of lower ejection fractions and a higher prevalence of congestive heart failure in group A patients.
| Variable | Group A ‡ | Group B § |
|---|---|---|
| (n = 31) | (n = 21) | |
| Age (years) | 63.4 ± 9.5 | 62.8 ± 13.2 |
| Men | 22 (71%) | 16 (76%) |
| Hypertension | 25 (81%) | 20 (95%) |
| Diabetes mellitus | 14 (45%) | 11 (52%) |
| Coronary artery disease ∥ | 18 (58%) | 13 (62%) |
| Heart failure ¶ | 23 (74%) ⁎ | 10 (48%) ⁎ |
| Left ventricular ejection fraction mean (%) | 32.5 ± 14.8 ⁎ | 41.2 ± 16.3 ⁎ |
| Atrial fibrillation | 10 (32%) | 9 (43%) |
| End-stage renal disease/hemodialysis | 7 (22%) | 3 (14%) |
| Serum creatinine † (mg/dl) | 1.8 ± 1.3 | 1.3 ± 0.4 |
| Glomerular filtration rate ≥60 mg/dl | 9 (29%) | 8 (38%) |
| Current alcohol abuse | 2 (6%) | 1 (5%) |
| Current intravenous drug use | 0 | 0 |
| Defibrillator vs pacemaker | 26 (84%) | 15 (71%) |
† Hemodialysis patient excluded.
‡ Bacteremia and/or device endocarditis.
§ Pocket involvement only, no bacteremia.
∥ History of ≥1 major coronary vessel stenosis ≥70% or requiring revascularization.
¶ Symptomatic depressed systolic function (left ventricular ejection fraction ≤35%).
Characteristics of the infected devices are listed in Table 2 . There was a high proportion of implantable cardioverter-defibrillators (79%), and the mean time from device implantation was 4.1 years.
| Characteristic | Frequency |
|---|---|
| Device type | |
| Pacemaker | 11 (21%) |
| Defibrillator | 41 (79%) |
| Cardiac resynchronization therapy with defibrillator | 14 (34%) ⁎ |
| Primary prevention | 37 (90%) ⁎ |
| Secondary prevention | 4 (10%) ⁎ |
| Cardiac leads | |
| 1 | 15 (29%) |
| 2 | 23 (44%) |
| ≥3 | 14 (27%) |
| Time from device implantation (years) | 4.1 ± 3.8 |
Table 3 lists the differences in clinical manifestations on presentation in the 2 groups. As expected, group A patients presented mainly with fever, hypotension, and other constitutional symptoms, while group B patients presented with local findings at the device generator pocket site. Echocardiography showed evidence of cardiac vegetations in 68% of group A patients and 5% of group B patients (p <0.001). Figure 1 shows the microbiology spectrum of all patients with bacteremia (i.e., group A). Staphylococcus aureus was the most prevalent microorganism isolated (69% of patients), with roughly half reflecting a methicillin-resistant strain. PLE was performed in all patients a mean of 5.0 ± 5.9 days after hospital admission. A mean of 2 ± 0.8 leads per patient were extracted. A laser sheath was used in 33 patients (63%). Lead extraction was incomplete, with residual hardware left in place, in 3 patients (6%). No fatal complications were observed. There were a total of 5 (10%) intraprocedural or postprocedural complications (2 classified as major and 3 as minor): 3 patients experienced postprocedural chest wall hematoma requiring surgical drainage (n = 1), transfusion of red blood cells (n = 1), and only clinical observation (n = 1); 1 patient experienced a brief episode of asystole shortly after the procedure, which resolved after a short course of cardiopulmonary resuscitation, with subsequent recovery without sequelae; and 1 patient had a perforation of the right ventricle during the procedure that required emergent repair via sternotomy by the cardiothoracic surgeon. Overall, the length of hospital stay was 14 ± 13 days. Ten patients died during the hospitalization (in-hospital mortality 19%) an average of 8 ± 8 days after PLE. Nine of 10 patients died because of sepsis or multiple-organ failure, and 1 patient died because of a laceration of the innominate vein during attempted reimplantation of a pacemaker lead. The patient was pacemaker dependent and had a venous stent in place with a residual severe stenosis of the central venous system due to previous catheters used for hemodialysis. Emergent sternotomy was performed by cardiothoracic surgery, but the patient died during the procedure. Table 4 lists details on procedural and in-hospital outcomes in the 2 groups. Patients in group B had leads that were significantly older than those in patients in group A (mean 5.5 vs 3.1 years, p = 0.02). There was no significant difference in terms of the number of leads extracted, the use of a laser sheath, rates of incomplete extraction, and procedure-related complications. PLE was performed significantly earlier in group B patients (average 7.6 vs 1.3 days after admission, p <0.001; Figure 2 ) . Length of hospital stay was also significantly shorter for group B patients (average 5.7 vs 21.7 days, p <0.001). Moreover, in-hospital death occurred significantly more often in group A patients (29% vs 4.7%, p = 0.02).
| Variable | Group A | Group B |
|---|---|---|
| (n = 31) | (n = 21) | |
| Systemic manifestations | ||
| Fever (≥38°C) | 81% | 14% |
| Hypotension (systolic blood pressure ≤90 mm Hg) | 68% | 19% |
| Other constitutional symptoms | 93% | 0 |
| Local findings at generator site | ||
| Erythema | 10% | 90% |
| Swelling | 13% | 57% |
| Tenderness | 10% | 62% |
| Erosion | 0 | 43% |
| Drainage | 13% | 86% |
| Purulent drainage | 13% | 43% |
| Laboratory abnormalities | ||
| Leukocytosis (white blood cell count ≥10,000/μl) | 97% | 33% |
| Positive blood cultures | 100% | 0 |
| Positive pocket cultures | 19% | 57% |
| Echocardiographic abnormalities | ||
| Cardiac vegetations | 68% | 5% |
| Lead | 68% | 0 |
| Valve | 19% | 5% |
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