2025 Southeastern Residency Conference

Title: 
LVADing the Way: Narrowing Antibiotics Without Increasing Infection Risk


Authors: 
Shyam Patel; Dusty Lisi; Mahmoud Abdou


Objectives: 
To evaluate the impact of different antimicrobial prophylaxis in patients undergoing LVAD implantation on infection free survival. 


Background: 
Driveline infections are one of the most serious and common complications associated with left ventricular assist device (LVAD) implantation. With an increase in prevalence of LVADs being used as a bridge to heart transplant or as destination therapy in end-stage heart failure, there is growing concern about optimizing perioperative antimicrobial management in LVAD procedures to prevent driveline infections and LVAD-associated infection (LVADI). Current guidelines for surgical infection prophylaxis (SIP) for LVAD implantation are not well established, leading to varied SIP regimens including single and multi-drug regimens covering the common pathogens such as Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, and Enterobacter species. Institutions may also opt to cover for rare fungal and Pseudomonas infection based on institution-specific pathogen prevalence and antimicrobial resistances.

Broad spectrum antimicrobials have been the regimen of choice for LVAD SIP; however, the overuse of antimicrobials has led to several undesirable outcomes such as antimicrobial resistance and increased healthcare costs with questionable effects on patient outcomes. Several recent studies have found that narrow LVAD SIP regimens did not impact the infection-free survival or all-cause mortality as compared to different multi-drug regimens.

On August 13th, 2023, Emory Healthcare changed its SIP for LVAD implantations. This updated protocol replaced the previous regimen containing micafungin, vancomycin, and cefepime/levofloxacin with one that contains vancomycin and cefuroxime. The goal of this study is to evaluate the effectiveness of this new narrower drug regimen without pseudomonas and fungal coverage and its outcome on infection-free survival and mortality in LVAD patients at our institution compared to the previous multi-drug broad spectrum SIP. 


Methods:
A multi-center, retrospective chart review IRB-approved study was conducted to analyze patients meeting inclusion criteria pre- and post-implementation of a standardized LVAD SIP protocol (August 13th, 2023). Included patients who were at least 18 years of age and had received either a HeartMate 2, HeartMate 3, or HeartWare device at Emory Saint Joseph’s Hospital or Emory University Hospital. Patients were excluded if they did not have antimicrobial prophylaxis documented at the time of LVAD surgery, were receiving antimicrobial therapy 2 weeks prior to LVAD implantation for a previously diagnosed infection or had with concerns for infection prior to procedure. The primary outcome was time-to-infection. Secondary outcomes included percent driveline infection within 1st year, time-to-mortality,  infection type, and organism type. 


Results (pre-protocol vs post-protocol implementation): 
Ultimately, 62 patients were included in the pre-protocol implementation group and 18 patients in the post-protocol implementation group. Baseline demographics were similar between the two groups with the exception of a lower BMI in the pre-protocol group (27.6 vs.29.8 kg/m², p=0.04) and a higher percentage of individuals requiring pre-operative mechanical support in the pre-protocol group (65% vs 39%, p=0.01).There were a greater percentage of documented LVADI in the pre-protocol group (37% vs 33%); however, this was not correlated to a decreased time to infection between the pre-protocol and post protocol groups (267 vs 454 days, p=0.76). Both groups had similar percentage of mortality (15% vs 17%) with no difference in time to mortality (1847 vs 423 days, p=0.85).


Conclusions: 
Following the implementation of a protocol to narrow LVAD SIP by replacing the previous regimen containing micafungin, vancomycin, and cefepime/levofloxacin with one that contains vancomycin and cefuroxime for LVAD surgeries, there was no change to time to LVADI or mortality. Despite the small sample sizes and the differences in their sizes, this antimicrobial stewardship strategy was successful in reducing improper antimicrobial use across out healthcare system without compromising patient outcomes.