Device exchange versus nonexchange modalities in left ventricular assist device‐specific infections: A systematic review and meta‐analysis

No standardized treatment algorithm exists for the management of continuous‐flow left ventricular assist device (CF‐LVAD)‐specific infections. The aim of this systematic review and meta‐analysis was to compare the outcomes of CF‐LVAD‐specific infections as managed by device exchange to other treatment modalities not involving device exchange. Electronic search was performed to identify all studies in the English literature relating to the management of CF‐LVAD‐specific infections. All identified articles were systematically assessed for selection criteria. Thirteen studies with 158 cases of CF‐LVAD‐specific infection were pooled for analysis. Overall, 18/158 (11.4%) patients underwent CF‐LVAD exchange, and 140/158 (88.6%) patients were treated with non‐exchange modalities. The proportion of patients with isolated driveline infections or pump or pocket infections did not differ significantly between the groups. During a mean follow‐up of 290 days, there were no significant differences in the overall mortality [exchange 17.6% (4.3–50.6) vs. non‐exchange 23.3% (15.8–32.9), P = 0.67] and infection recurrence rates [exchange 26.7% (8.7–58.0) vs. non‐exchange 38.6% (15.4–68.5), P = 0.56]. In the setting of CF‐LVAD‐specific infections, device exchange does not appear to confer an advantage in the overall mortality and infection recurrence as compared to non‐exchange modalities.     

HeartMate‐II Left Ventricular Assist Device Infections Resulting from Gastrointestinal‐Tract Fistulas

Abstract Background: In patients with a left ventricular assist device (LVAD), pump‐related infection can cause adverse effects that may result in death. Methods: We describe three patients who had infections related to a fistula between the gastrointestinal (GI) tract and the LVAD pocket and who subsequently underwent successful heart transplantation without developing sepsis. In no case did the LVAD‐related infection adversely affect the outcome of transplantation. Conclusions: For detecting the fistulas, full upper‐GI endoscopy and colonoscopy were superior to other types of diagnostic imaging studies. (J Card Surg 2012;27:643‐645)     

Clinical Outcomes Associated With Chronic Antimicrobial Suppression Therapy in Patients With Continuous‐Flow Left Ventricular Assist Devices

This retrospective cohort study evaluates the effect of chronic antimicrobial suppression (CAS) therapy on clinical outcomes in patients with continuous‐flow left ventricular assist devices (CF‐LVADs) and a history of device‐related infection. Patients with CF‐LVAD implantation between January 2008 and August 2011 who received systemic CAS after index antibiotic treatment of a device‐related infection were included. Chronic suppression was defined as continuation of antibiotics for longer than 6 weeks after the index infection. Standard International Society for Heart and Lung Transplantation definitions were used. The primary outcome is failure of CAS, defined as a clinical deterioration resulting in the need for transition from oral to intravenous (IV) therapy or a need to change to a different IV antibiotic, elevation to status 1A on the transplant list as a result of ongoing infection, or device/driveline exchange. Of 140 patients screened, 16 patients were included (69% male, 63% African American, median age 52 years). The driveline was the most common site of infection (69%). Organisms isolated included Gram‐positive cocci (n = 7), Gram‐negative bacilli (n = 10), and Candida (n = 1). Oral trimethoprim/sulfamethoxazole treatment was most commonly used for suppression (37.5%). Failure of CAS occurred in 5/16 (31%) patients after a mean time of 175 days on therapy (range 10–598). The majority of failures (60%) required device exchanges. Side effects of nausea, vomiting, or diarrhea were reported in three patients; all required changes in oral suppression regimen. Clostridium difficile infection was noted in two patients. These results, which must be confirmed by a larger analysis, suggest that one‐third of CF‐LVAD patients may develop recurrent infections while on CAS therapy.     

Does the Type of Ventricular Assisted Device Influence Survival,Infection, and Rejection Rates Following Heart Transplantation?

Abstract Objective: To determine the influence of the type of left ventricular assisted device (LVAD) as predictor of survival, hospitalizations due to infection, and rejection following heart transplantation and to delineate any further predictors of such outcomes. Methods: Patients who received a left ventricular assist device (HeartMate [Thoratec Corp., Pleasanton, CA, USA] or Novacor [World Heart Corporation, Ottawa, Canada]) as a bridge to heart transplantation between October 1991 and June 2004 using the United Network for Organ Sharing (UNOS) Thoracic Registry database were evaluated. Comparison of survival curves between HeartMate and Novacor was performed using Kaplan–Meier survival method and Cox proportional hazard model adjusting for patient demographics and co‐morbidities. Infection and rejection rates between the two devices were analyzed using multivariable logistic regression model. Results: The UNOS database provided 1255 patients with HeartMate and 154 patients with Novacor between 1991 and 2004. Unadjusted one‐ and five‐year survivals for HeartMate and Novacor were 0.84 and 0.80 and 0.72 and 0.56, respectively, following heart transplantation. Adjusting for patient demographics and co‐morbidities, no statistical significant difference in one‐year survival was observed between those who received HeartMate and Novacor (HR = 1.49, p = 0.127). At five years, however, the HeartMate group had higher survival than Novacor (HR = 1.53, p = 0.043). All‐time posttransplant hospitalizations due to infection and rejection were similar between HeartMate and Novacor recipients after adjusting for patient case mix. Conclusion: Controlling for patient case mix, there was no survival difference at one year between those who received Novacor versus HeartMate LVAD. At five years, a Novacor bridge to transplant patient on average had statistically significantly lower survival than HeartMate recipients. No difference in infection and rejection were observed.     

HeartMate left ventricular assist devices: a multigeneration of implanted blood pumps

The HeartMate family of implanted left ventricular assist devices (LVADs) developed by Thermo Cardiosystems, Inc. (TCI) span a time frame that goes back to the beginning of clinical use of mechanical circulatory support and will stretch well into the foreseeable future. Associated blood pump technology employed in the HeartMates range from an original pusher plate concept to the most advanced rotary pump devices. Starting initially with a pneumatic actuated pusher plate pump, clinical use of the HeartMate I began in 1986. In 1990, electric motor-actuated versions of the HeartMate I began to be used clinically. Presently, the HeartMate I has been implanted in some 2,300 patients worldwide, and this LVAD is a standard by which all others are currently measured. Following the HeartMate I is TCI's next-generation, the HeartMate II, a rotary-pump-based LVAD that uses an axial flow blood pump having blood immersed mechanical bearings. Clinical trials of the HeartMate II were initiated in 2000. The HeartMate III, representing TCI's next-generation LVAD, is structured around a centrifugal blood pump that uses a magnetically levitated rotating assembly. Compared to the HeartMate II, the HeartMate III has the potential for higher overall efficiency. The pump's operating life is not dependent on bearing wear. Given the significantly advanced LVAD technology represented by HeartMates II and III, coupled with the experience of HeartMate I, TCI is well-poised to keep its LVAD products as industry standards in the future.     

Optimal cannula positioning of HeartMate 3 left ventricular assist device

Cannula position in HeartMate II and HeartWare left ventricular assist devices (LVADs) is associated with clinical outcome. This study aimed to investigate the clinical implication of the device positioning in HeartMate 3 LVAD cohort. Consecutive patients who underwent HeartMate 3 LVAD implantation were followed for one year from index discharge. At index discharge, chest X-ray parameters were measured: (a) cannula coronal angle, (b) height of pump bottom, (c) cannula sagittal angle, and (d) cannula lumen area. The association of each measurement of cannula position with one-year clinical outcomes was investigated. Sixty-four HeartMate 3 LVAD patients (58 years old, 64% male) were enrolled. In the multivariable Cox regression model, the cannula coronal angle was a significant predictor of death or heart failure readmission (hazard ratio 1.27 [1.01-1.60], P = .045). Patients with a cannula coronal angle ≤28° had lower central venous pressure (P = .030), lower pulmonary capillary wedge pressure (P = .027), and smaller left ventricular size (P = .019) compared to those with the angle >28°. Right ventricular size and parameters of right ventricular function were also better in the narrow angle group, as was one-year cumulative incidence of death or heart failure readmission (10% vs. 50%, P = .008). Narrow cannula coronal angle in patients with HeartMate 3 LVADs was associated with improved cardiac unloading and lower incidence of death or heart failure readmission. Larger studies to confirm the implication of optimal device positioning are warranted.     

Use of Left Ventricular Assist Device (HeartMate II): A Singapore Experience

Recent advances in medical and device therapies in heart failure have improved the survival of patients with heart failure. However, due to the limited availability of suitable heart donors, left ventricular assist devices (LVADs) have become an important tool as a bridge‐to‐heart transplantation for patients with refractory heart failure in Singapore. We report our experience with the HeartMate II (HMII) LVAD (Thoratec Corporation, Pleasanton, CA, USA) as a bridge‐to‐heart transplant in our center from 2009 to 2012. This was a retrospective review of 23 consecutive patients who underwent HMII LVAD implantation in our center between May 2009 and December 2012. All patients were classified as Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) levels 1 to 3 and underwent LVAD implantation as a bridge‐to‐heart transplant. There were 17 male and 6 female patients. The mean age was 43.6 years old (range 14 to 64). The etiologies of heart failure included ischemic heart disease [8], idiopathic dilated cardiomyopathy [11], viral myocarditis [2], and chemotherapy‐induced cardiomyopathy [2]. Nine patients were INTERMACS level 1, 12 patients level 2, and two patients level 3. All patients successfully underwent HMII LVAD implantation. There was no mortality within the first 30 postoperative days. Postoperative complications included stroke with full neurological recovery (21.7%), mediastinal infection (21.7%), cardiac tamponade or mediastinal collection requiring reopening of the chest (39.1%), cardiac arrhythmia (13.0%), and pump thrombosis with pump replacement (4.3%). All patients were discharged from hospital after LVAD implantation. Three patients experienced driveline infections during outpatient follow‐up. There were 19 readmissions due to the following conditions: sub‐therapeutic anticoagulation (13.0%), gastrointestinal bleeding (13.0%), suspected pump thrombosis (13.0%), transient ischemic attack (8.7%), arrhythmia (8.7%), congestive cardiac failure due to severe aortic regurgitation (8.7%), right ventricular failure (4.3%), rhabdomyolysis (4.3%), and hematuria (4.3%). Post‐LVAD implantation, 20 patients were functionally New York Heart Association (NYHA) class I, while 3 reported NYHA III symptoms. Three patients were successfully bridged to heart transplantation. One patient was successfully explanted 11 months after LVAD implantation. There were two mortalities during the follow‐up period. The average duration of LVAD support was 522 days (range 47 to 1316 days). The HeartMate II LVAD has proven to be effective in our Asian population. Driveline infection rate remains low even in the tropical hot, humid climate in Singapore. With more patients ending up on extended periods of LVAD support, increased emphasis in the detection and management of long‐term complications of ventricular assist devices will be needed.     

Cardiac Index Declines During Long‐Term Left Ventricular Device Support

To investigate longitudinal trends in valvular and ventricular function with long‐term left ventricular assist device (LVAD) therapy, we analyzed hemodynamic and echocardiographic data of patients with at least 2 years of continuous LVAD support. All 130 patients who underwent HeartMate II implantation at our institution between 2005 and 2012 were reviewed. Twenty patients had hemodynamic and echocardiographic evaluations in both the early (0–6 months) and late (2–3 years) postoperative period. Patients on inotropic therapy or temporary mechanical support were excluded. The average times of early and late hemodynamic evaluations were 59 ± 41 days and 889 ± 160 days, respectively. Cardiac index (CI) declined by an average of 0.4 L/min/m² (P = 0.04) with concomitant increase in pulmonary capillary wedge pressure (PCWP; P = 0.02). The right atrial pressure to PCWP (RAP:PCWP) ratio decreased during LVAD support suggesting improvement in right ventricular function. While there was an increase in degree of aortic insufficiency (AI) at the late follow‐up period (P = 0.008), dichotomization by median decline in CI (?0.4 L/min/m²) indicated no difference in prevalence of AI among the groups. CI declined in patients with HeartMate II after 2 years of continuous support. An increase in preload and afterload was observed in those with the greatest decline in CI.     

The Jarvik 2000 is associated with less infections than the HeartMate left ventricular assist device.

OBJECTIVES: Device-related infections remain a considerable problem of left-ventricular support. We compared the device-related-infections between the HeartMate left ventricular assist device (LVAD) and the Jarvik 2000 permanent LVAD, a device with a novel retroauricular power-supply. METHODS: Between December 2000 and September 2002 we implanted the HeartMate-vented, electrical-system in 11 patients and the permanent Jarvik 2000 in six patients. Total support time was 1626 patient-days (HeartMate, 26-271 days) versus 1246 patient-days (Jarvik 2000, 8-411 days). As potential risk factors for infection we analyzed age, preoperative hospital-days, total protein, cardiac index, maximal oxygen uptake, use of inotropes, LVAD risk-score-index and Aaronson-Mancini-score, intubation time, and intensive care unit stay. We used the Center of Disease Control definitions for surgical site infections. RESULTS: HeartMate-patients were younger than Jarvik 2000 patients (46+/-13 versus 58+/-6 years, P=0.056), there were no other differences in the risk factors. Four HeartMate-patients needed late (>or=48 h) surgical revisions for bleeding/hematomas versus no revisions in the Jarvik 2000 patients. In the HeartMate-patients, there were seven (64%) driveline-infections, five (45%) device-pocket infections, and three (27%) bloodstream-infections, or 0.43 device-related infections/100 patient-days. Infections occurred early (34+/-31 days). Three patients required urgent transplantation due to bloodstream infection. There were no adverse outcomes in the HeartMate-group due to infection. In the Jarvik 2000 patients, there was one driveline-infection (16%) after 270 days of support (0.08 device-related infections/100 patient-days), significantly less than in the HeartMate-group (P=0.044). Driveline infections resolved with antibiotics and local wound care in the Jarvik 2000 patient, but only in one of seven HeartMate-patients. CONCLUSIONS: Implantation of the Jarvik 2000 is associated with less device-related infections than the HeartMate-LVAD. The power-supply of the permanent Jarvik 2000 is suitable for long-term mechanical support.     

Continuous‐Flow Left Ventricular Assist Device Therapy in Patients With Preoperative Hepatic Failure: Are We Pushing the Limits Too Far?

The purpose of this study was to evaluate the effects and outcome of continuous‐flow left ventricular assist device (cf‐LVAD) therapy in patients with preoperative acute hepatic failure. The study design was a retrospective review of prospectively collected data. Included were 42 patients who underwent cf‐LVAD implantation (64.3% HeartMate II, 35.7% HeartWare) between July 2007 and May 2013 with preoperative hepatic failure defined as elevation of greater than or equal to two liver function parameters above twice the upper normal range. Mean patient age was 35 ± 12.5 years, comprising 23.8% females. Dilated cardiomyopathy was present in 92.9% of patients (left ventricular ejection fraction 17.3 ± 5.9%). Mean support duration was 511 ± 512 days (range: 2–1996 days). Mean preoperative laboratory parameters for blood urea nitrogen, serum creatinine, total bilirubin, and alanine aminotransferase were 9.5 ± 5.4 mg/dL, 110.3 ± 42.8 μmol/L, 51.7 ± 38.3 mmol/L, and 242.1 ± 268.6 U/L, respectively. All parameters decreased significantly 1 month postoperatively. The mean preoperative modified Model for Endstage Liver Disease excluding international normalized ratio score was 16.03 ± 5.57, which improved significantly after cf‐LVAD implantation to 10.62 ± 5.66 (P < 0.001) at 7 days and 5.83 ± 4.98 (P < 0.001) at 30 days postoperatively. One‐year and 5‐year survival was 75.9 and 48.1%, respectively. 21.4% of the patients underwent LVAD explantation for myocardial recovery, 16.7% were successfully transplanted, and 7.1% underwent LVAD exchange for device failure over the follow‐up period. Patients with preexisting acute hepatic failure are reasonable candidates for cf‐LVAD implantation, with excellent rates of recovery and survival, suggesting that cf‐LVAD therapy should not be denied to patients merely on grounds of “preoperative elevated liver enzymes/hepatopathy.”     

Nontuberculous mycobacterial infections in left ventricular assist device patients

Left ventricular assist devices (LVADs) are integral for the management of medically refractory heart failure, and LVAD infections are common following device placement. Most infections are caused by Staphylococcal spp. and Gram-negative enteric bacteria but nontuberculous mycobacterial (NTM) infections have been reported. We present the second-ever reported case of a driveline infection caused by Mycobacterium fortuitum in a 75-year-old male with a continuous-flow LVAD. After receiving meropenem, azithromycin, and ciprofloxacin, he underwent device exchange and ultimately died after failing to recover neurologically. Management of NTM infections presents a clinical challenge due to the propensity for rapidly growing mycobacterial species to form biofilms and the possibility of negative cultures delaying diagnosis. To address the literature gap surrounding NTM infections in LVAD patients, we performed a systematic review and present all previously reported cases.     

Early Aspirin Nonresponders Identification by Routine Use of Aggregometry Test in Patients With Left Ventricle Assist Devices Reduces the Risk of Pump Thrombosis

Left ventricular assist device (LVAD) management is very challenging since many adverse events can occur in ongoing patients. Inadequate anticoagulation treatment can lead to life-threatening situations like ischemic stroke or pump thrombosis. The main intention of our study was to investigate if early identification of aspirin nonresponders by using aggregometry can improve anticoagulation management, reducing the risk of pump thrombosis.MethodsFrom December 2010 to May 2018, 24 patients were implanted with a HeartMate II (HMII), 6 received a HeartWare HVAD system--full support VAD (HVAD), and 22 received a HeartMate III (HMIII). All patients were maintained with a target INR of 2.0 to 3.0. When the aggregometry test revealed a normal platelet function, 100 mg of aspirin were initiated. Only aspirin nonresponders were early identified by repeating the aggregometry after 7 days of aspirin administration. In acetylsalicylic acid nonresponder patients, 75 mg of clopidogrel was used, and the patients were tested again. Ticlopidine (250 mg) was used when clopidogrel was unsuccessful.ResultsFour patients required modification in antiplatelet therapy. Three patients (5%), 2 HVAD and 1 HMII, suffered from pump thrombosis. One patient died as a consequence of a large intracranial hemorrhagic event following thrombolytic treatment. One patient required a pump exchange; in 1 patient, thrombolytic infusion was conducted successfully.ConclusionReported rates of pump thrombosis at 12 months for patients implanted with commonly used LVADs were 6% to 12% for axial-flow pumps and 8% with centrifugal-flow devices. In our series, the reported 5% overall incidence of pump thrombosis encourages the routine use of an aggregometry test for early identification of aspirin nonresponders.     

The Cohn felt plug: an effective HeartMate II® reimplantation technique

Abstract We report the first documented case of HeartMate II® left ventricular assist device (LVAD) reimplantation following Cohn Teflon felt plug repair of the initial left ventricular apical cannulation site. This case highlights the current limitations of the predictability of myocardial recovery while describing an effective technique for possible future LVAD reimplantation.
(J Card Surg 2012;27:122–124)     

Intraoperative left atrium inversion after implantation of HeartMate III ventricular assist device

We report here a case of left atrium inversion after implanting HeartMate III LVAD, which is known to be the first in literature. LVAD can be functional only if there is adequate inflow to the device. Parameters and filling of left ventricle can be assessed by TEE. In our case, initial examination with TEE showed thrombus like images. HeartMate III has a reliable algorithm that automatically reduces pump speed if ‘suction effect’ is detected. HeartMate III demonstrates clean flow properties and good surface wash. Despite these positive features of the HeartMate III, left atrium inversion can still be seen with it, so users should be alert in this regard.     

Successful replacement of malfunctioning TCI HeartMate LVAD with DeBakey LVAD as a bridge to heart transplantation

Congestive heart failure is the leading cause of hospitalization and death in the developed world and affects about 0.4-2% of the adult population [Ann Thorac Surg 1999;68:637-40]. Heart transplantation remains the most effective therapy for end-stage heart disease, but the shortage of donors has led to increasing interest in other surgical options, especially ventricular assist devices (VAD). Several VADs are available to bridge patients to transplantation [N Engl J Med 2001;345:1435-43], including pulsatile devices like the HeartMate (HeartMate, Thoratec, Pleasanton, CA) and Novacor (World Heart, Netherlands), and the DeBakey VAD (MicroMed Technology, Inc., Houston, TX), which is an electromagnetically driven implantable titanium axial flow blood pump designed for left ventricular support. Despite technical improvements, VADs still are associated with serious complications. We reporte a successfull case where we replaced a TCI HeartMate with a DeBakey VAD because of a serious pocket infection, deterioration and failure of the inflow valve.     

Fungemia Associated with Left Ventricular Assist Device Support

Abstract  Objective: Infections remain an important complication of left ventricular assist device (LVAD) support. While relatively uncommon, fungal infections present a serious concern given a high association with adverse events including death. We sought to further characterize the epidemiology of fungemias during LVAD support. Methods: Retrospective review of 292 patients receiving LVAD support from October 1996 to April 2009 at the University of Michigan Health System was done. Results: Seven cases of LVAD-associated fungemia were observed during the study period (0.1 infections/1000 days of device support). Five patients had infection with Candida species and two with Aspergillus species. The two patients with Aspergillus infection presented with disseminated disease, quickly dying of multiorgan failure, and sepsis. All five patients with Candida infections were successfully treated with systemic antifungal therapy along with transplantation in four of five patients. The fifth patient is receiving mechanical support as destination therapy. He remains on long-term suppression with high-dose fluconazole. Conclusions: Fungal infections appear to be a rare but serious complication of LVAD support. Future studies should aim to improve our understanding of risk factors for fungal infection during mechanical support, especially disseminated Aspergillus . Short-term perioperative antifungal prophylaxis with fluconazole appears to be an effective and reasonable approach to prevention.     

Importance of Early Appropriate Intervention Including Antibiotics and Wound Care for Device-Related Infection in Patients With Left Ventricular Assist Device

Introduction

A left ventricular assist device (LVAD) is essential for treating patients with advanced heart failure. However, LVAD-related infection is a significant cause of mortality and morbidity, with bloodstream infection (BSI) especially associated with high mortality. We investigated the incidence of infectious complications in patients who received an LVAD and evaluated the effects of early and appropriate intervention for LVAD-related infection.

Method

We retrospectively reviewed 27 consecutive patients who underwent continuous-flow LVAD (CF-LVAD; n = 16) or pulsatile-flow LVAD (PF-LVAD; n = 11) implantation at the National Cerebral and Cardiovascular Center between April 2011 and March 2013. Incidences of LVAD-related infections, such as drive-line infection in patients with CF-LVAD, cannula infection in patients with PF-LVAD, and BSI in patients with both types, were examined (follow-up period, 342 ± 229 days). The mandatory antibiotic prophylaxis protocol at our institution includes teicoplanin (400 mg) 2 days before LVAD implantation and doripenem (1000 mg) within 1 hour of skin incision. In addition, the driveline exit sites undergo sterile cleansing with diluted hydrogen peroxide and placement of an antimicrobial occlusive dressing for wound care, with dressing changes performed 2–3 times per day.

Results

More than 90% of all patients suffered from a drive-line infection within 12 months after LVAD implantation. However, BSI developed in only 12.5% of CF-LVAD and 10% of PF-LVAD patients within 12 months (log-rank test; P = .875).

Conclusions

LVAD-related infections, such as drive-line and cannula infections, were common, whereas the incidence of BSI was low in our LVAD-implanted patients. Our results highlight the importance of early and appropriate intervention including antibiotics and wound care for device-related infections for reducing the incidence of potentially fatal BSI.     

Development of an infection-resistant LVAD driveline: a novel approach to the prevention of device-related infections.

BACKGROUND: Infection remains the single most important challenge to extended left ventricular assist device (LVAD) use and often arises from the percutaneous driveline exit site. We evaluated the ability of an LVAD driveline prototype impregnated with chlorhexidine, triclosan, and silver sulfadiazine to resist bacterial and fungal colonization. METHODS: The spectrum and duration of antimicrobial activity were evaluated in vitro by daily transfer of driveline segments embedded on agar plates inoculated with 10(8) colony-forming units (CFU) of Staphylococcus aureus (S. aureus), Staphlococcus epidermidis, Enterobacter aerogenes, Psuedomonas aeruginosa, and Candida albicans, and then measuring zones of inhibition around the sample subsequent to 24 hours of incubation at 37 degrees C. Antimicrobial activity was demonstrated against all organisms for greater than 14 days, and for over 21 days for gram-positive bacteria. To demonstrate in vivo efficacy of the treated driveline, 3-cm segments of driveline were implanted in the dorsal and ventral surface of rats. The exit site was inoculated with 10(6) CFU of S. aureus. After 7 days, driveline segments were aseptically explanted and assayed for bacterial colonization and retention of antimicrobial activity. One hundred percent of control segments were colonized (10(5) CFU S. aureus/cm) as against 13% of the test explants (< or = 330 CFU/cm; p < 0.0001). RESULTS: Subcultures of the insertion site and driveline pocket tissue resulted in 10(3) to 10(5) CFU per swab culture for control rats and 0 to 10(2) CFU/swab for test animals. Test drivelines retained 80% of anti-S. aureus activity. Gross and histological examination of the driveline and surrounding pocket revealed minimal tissue reactivity with positive signs of tissue ingrowth. CONCLUSION: An antimicrobial driveline may prevent early infections and facilitate ingrowth of tissue to provide long-term stability and protection against late infection.