The primary goal for developing this kit was to provide all the components required by the patient for performing a dressing change in a single kit that could simplify the dressing change procedure. Additionally, training was provided by the VAD coordinators to ensure that all patients were performing the dressing change the same way. The components of the kit include the following: Kendall Webcol swab (Covidien, Mansfield, MA) (70% isopropyl alcohol), hair cover, mask, nonlatex gloves, wrap, Chlorascrub Maxi Swabstick (Professional Disposables International, Inc, Orangeburg, NY), and Swab for site preparation; 3M Cavilon No Sting Barrier Film (3M Critical & Chronic Care Solutions, St. Paul, MN) to reduce skin irritation; a 1.5 × 1.5 inch Silverlon Wound Pad Dressing (Argentum Medical, LLC, Geneva, IL), sterile saline, and Styrofoam tray for infection mitigation; SorbaView Ultimate dressing (Centurion Medical Products, Williamston, MI) with securement tape for stabilizing the driveline; and a Foley anchor (Centurion Medical Products, Williamston, MI) for additional strain relief support. All components of the PLMK were recommended to be changed every 7 days.
REduce Driveline Trauma through StabIlization and Exit Site ManagemenT (RESIST) was a multicenter, prospective, self-controlled study that was designed to evaluate the feasibility of the PLMK. Fifty patients were enrolled from five participating medical centers located in different climates in the United States. The primary objective was to evaluate the use of the PLMK for 30 days. The patient or caregiver recorded the patient’s subjective assessments after using the PLMK. Secondary objectives evaluated the incidence of infection, adverse reaction to any PLMK components, the efficacy of the antiseptic sponge (Silverlon), and the stabilization system (SorbaView Ultimate with securement tape). The follow-up period was 30 days for patient stabilization and for comfort assessment. Patients were followed for an additional 2–6 months from enrollment for infection assessment. Infections were determined by physical examination and cultures of the drainage from the site when indicated. After the 30 days follow-up period, patients had the option to continue using the PLMK or resume their original protocol. Patients were allowed to shower as part of the study. If the patient showered, he/she was instructed to contact the VAD coordinator after their first shower to assess the integrity of the dressing. A role of Press’n Seal (Glad Product Company, Oakland, CA) and 3M Transpore adhesive tape were provided to the patient as an additional measure to keep the exit site dry while showering.
The study included 50 patients who were older than 16 years, with ongoing HM2 (Thoratec Corporation) support, who had been discharged from the hospital with no signs or symptoms of driveline exit site infection at the time of enrollment, and who had no known allergies to products used in the PLMK. The patient or caregivers were instructed to change the dressing every 7 days for the 30 days study period. Patients completed questionnaires before and after the PLMK 30 days trial period to assess ease of use, comfort, and compliance with using the kit. Patients took photos of the exit site care in stages to verify proper application and completed case report forms at the time of the dressing change (Figure 2). The study protocol was approved by the Institutional Review Board of each participating center, and signed informed consent was obtained from all participants.
Continuous variables were presented as mean ± SD. Discrete variables and adverse events were presented as percentages. Freedom from driveline infection was calculated with the Kaplan–Meier method with patients censored for transplantation, death, or withdrawal. Differences in categorical variables were evaluated with the Fisher exact test. Each patient served has his/her own control for all the comparisons. p values and percentages were calculated using both the as-treated (AT) and the intention-to-treat (ITT) principles. The ITT analysis utilized the 50 patients who were enrolled into the study as the denominator, whereas the AT analysis utilized only the patients who utilized the kit for 30 days (N = 46). All statistical comparisons were two sided with a significance level at a p value of less than 0.05. All statistical analyses were done with SAS software (SAS Institute, Inc., Cary, NC).
The 50 patients enrolled in the study had a mean age of 62 ± 11 years, and 46 (92%) were men (Table 1). Patients were on LVAD support for a median of 496 days (range, 179–1,583 days) at the time of enrollment. Four patients (8%) had prior driveline infections, but they were resolved at the time of enrollment. Forty patients (80%) had the driveline placed with a silicone–skin interface with the velour completely below the skin, and the remainder had a velour–skin interface placement (i.e., the velour is exposed). Table 2 shows the driveline exit site management approaches for the five institutions before incorporating the PLMK as part of the RESIST study. Dressing change frequency before PLMK was daily or every 2–3 days for all patients.
Of the 50 patients enrolled in this study, 46 (92%) used the PLMK for greater than 30 days and 35 (70%) for greater than 6 months. Out of the 15 patients who were no longer on PLMK at 6 months, 7 can be attributed to the kit itself (skin irritation: 4 patients, 3 patients driveline infection [1 < 30 days, 2 > 30 days]), 3 were attributed to non–kit-related reasons where the subject did not adhere to the VAD coordinator’s instructions, and 5 were attributed to the patient outcome (3 were transplanted and 2 expired). Four patients used the PLMK for less than 30 days; of those, three stopped because of skin irritation and one stopped because of a driveline infection. For the entire group of 50 patients, 3 (6%) developed driveline infections, and the overall freedom from the event at 180 days was 93% ± 4% (Figure 3), with an event rate of 0.15 events per patient year.
Of the 46 patients who completed the 30 days study requirements, 37 patients (74% [ITT], 80%[AT]) found the PLMK to be extremely comfortable compared with 17 patients (34%[ITT], 37%[AT]) using the prior standard of care dressing (p < 0.001 [ITT and AT]) (Figure 4A). Twenty-four (48% [ITT], 52% [AT]) experienced at least one level of improvement in comfort with PLMK use, and 18 (35% [ITT], 39%[AT]) reported no change when compared with their previous technique. With respect to ease of use, 33 patients (66% [ITT], 72% [AT]) found the PLMK to be extremely easy to use compared with 26 patients (52% [ITT], 57% [AT]) using their prior standard of care dressing (p = 0.222 [ITT], p = 0.192 [AT]) (Figure 4B). Eleven patients (22% [ITT], 24% [AT]) improved by at least one level in ease of use with the PLMK, and 30 (60% [ITT], 65% [AT]) reported no change.
For the PLMK stabilization technique, 41 patients (82% [ITT], 89% [AT]) were extremely satisfied with the PLMK compared with only 20 patients (40% [ITT], 43% [AT]) with the prior standard of care dressing (p < 0.001 [ITT and AT]) (Figure 5A). Twenty-four patients (48% [ITT], 52% [AT]) reported at least one level of satisfaction improvement, and 18 (36% [ITT], 39% [AT]) reported that there was no change when compared with their prior technique. Six patients (12% [ITT], 13% [AT]) reported improved cleanliness of the exit site with use of the PLMK, and 35 (70% [ITT], 76% [AT]) said that there was no difference between the techniques in the degree of cleanliness of the exit site (p = 1.00 [ITT and AT]) (Figure 5B). Patients changed their dressing less frequently with the PLMK compared with their prior dressing with 85% of doing the dressing change only every 6–7 days or more than 7 days. With the prior standard of care dressing, 100% of the patients were recommended to change the dressing either daily or once every 2–3 days.
The VAD coordinators overwhelmingly (98%) rated the PLMK superior to the prior techniques with regard to stabilization, cleanliness, ability to avoid infection, and ease of use. Out of the five primary VAD coordinators, two indicated that they would recommend the PLMK to 100% of their patients, two said that they would recommend the PLMK to 75–99% of the patients, and one said that she would recommend to 50–74% of the patients. The VAD coordinator who selected the 50–74% of the option claimed that the other 25–50% may have issues with their driveline exit site and would require more frequent dressing changes. The VAD coordinators who felt that they would recommend the kit to 100% of their patients found the kit to be very effective and provided more freedom to patients without having to use a binder.
Since the initial implants of durable LVADs 25 years ago, device-related infections have been a serious complication in numerous patients.10–12 Infectious complications have declined considerably since the inception of continuous-flow LVADs, but driveline infection occurs in approximately 20% of patients in the first year of LVAD support, and the cumulative risk is continuous during support.13 Effective care and management of the driveline exit site is essential to optimizing the outcomes of LVAD therapy, and the PLMK may be an additional step toward that end. The primary goal for developing this kit was to provide all the components required by the patient for performing a dressing change in a single kit that would 1) simplify the dressing change procedure and 2) reduce the frequency of dressing changes. The RESIST study was a 30 days feasibility study of utilizing the PLMK for HM2 driveline exit site management, with patients followed-up to 6 months in order to evaluate the infection rate.
The PLMK improved comfort and stability in at least 50% of patients when compared with previous infection management systems. Additionally, the PLMK dressing changes were only performed once a week. As more and more patients receive these devices for DT, patient compliance becomes an important variable in reducing variability and the subsequent risk of driveline infection. Simplifying and improving the dressing change technique may further reduce the risk of driveline infection, in addition to reduce the risk of infection surgically by internalizing the velour portion of the driveline at the time of VAD implant. A recent multicenter study by Dean et al.14 demonstrated a 50% reduction in driveline infection rate at 1 year when the velour portion of the driveline was internalized, when compared with the HM2 clinical trial where the velour portion was externalized. Majority of the centers have now adopted this technique, including the patients in our study where 80% of the patients had the velour portion internalized.
Trauma at the skin exit site of the driveline is an event that precipitates most driveline infections. Avoiding trauma is difficult because of the relative rigidity of the driveline to the flexible abdominal wall.15–17 The most common method for driveline immobilization and site protection has been with the use of an abdominal binder. These binders can be effective in preventing pulling of the driveline, but since some patients consider them uncomfortable, they are less likely to use them on a regular basis. The stabilization approach comprising of the Sorbaview Ultimate Dressing and the Foley anchor does increase the comfort associated with the dressing change, which increases the likelihood of patient compliance with the dressing change protocol.
Silverlon Wound Pad Dressing is a commercially available dressing used in a wide variety of infection mitigation applications.18,19 Silver is known for its antimicrobial properties and has been used recently for reducing bacterial colonization near surgical wounds and catheter insertion sites. The Silverlon Wound Pad Dressing has been shown to be effective against Staphylococcus aureus, Staphylococcus epidermis, Pseudomonas aeruginosa, and Enterococcus faecium, which are common pathogens associated with LVAD driveline infections. Furthermore, Silverlon has a unique technology, which releases silver ions continuously during a period of 7 days in order to protect the exit site from bacterial colonization for the entire duration of use.20,21
This was a nonrandomized study, which may result in enrollment bias, and hence results should be viewed within the context of a feasibility, pilot study. Larger prospective randomized studies are needed in order to conclusively determine the clinical impact of the PLMK. Another limitation is that the study utilized subjective assessments by patients in order to evaluate study endpoints. Patient compliance with detailed instruction on the site care is variable and cannot be controlled in a study such as this. Studies with longer follow-up durations (minimum 1 year) are required before impact on driveline infection can be determined.
A PLMK that is easy to use, increases patient comfort, and increases driveline stability with a decreased dressing change frequency of 6–7 days from daily to 3–4 days was developed and evaluated as part of this feasibility study. The kit may help reduce variability and simplify the process of driveline exit site management and increase patient compliance. When used in combination with other infection control and prevention modalities, exit site infections may be better prevented; however long-term studies are needed before the impact of the PLMK can be conclusively determined.
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Keywords:Copyright © 2016 by the American Society for Artificial Internal Organs
driveline infection; exit site trauma; driveline stabilization; percutaneous lead