Impact of Obesity on Ventricular Assist Device Outcomes: Obesity and VAD Outcomes

© 2019 Elsevier Inc. Background: Obesity remains a relative contraindication for heart transplantation, and hence, obese patients with advanced heart failure receive ventricular assist devices (VADs) either as a destination or “bridge to weight loss” strategy. However, impact of obesity on clinical outcomes after VAD implantation is largely unknown. We sought to determine the clinical outcomes of obese patients with body mass index (BMI) ≥ 35 kg/m2) following contemporary VAD implantation. Methods: The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) registry was queried for patients who underwent VAD implantation. Patients were categorized into BMI groups based on World Health Organization classification. Results: Of 17,095 patients, 2620 (15%) had a BMI ≥ 35 kg/m2. Obese patients were likely to be young, non-white, females with dilated cardiomyopathy and undergo device implantation as destination. Survival was similar amongst BMI groups (P = .058). Obese patients had significantly higher risk for infection (hazard ratio [HR]: 1.215; P = .001), device malfunction or thrombosis (HR: 1.323; P ≤. 001), cardiac arrhythmia (HR: 1.188; P = .001) and hospital readmissions (HR: 1.073; P = .022), but lower risk of bleeding (HR: 0.906; P = .018). Significant weight loss (≥10%) during VAD support was achieved only by a small proportion (18.6%) of patients with BMI ≥ 35 kg/m2. Significant weight loss rates observed in obese patients with VAD implantation as destination and bridge to transplant strategy were comparable. Obese patients with significant weight loss were more likely to undergo cardiac transplantation. Weight loss worsened bleeding risk without altering risk for infection, cardiac arrhythmia, and device complications. Conclusions: Obesity alone should not be considered a contraindication for VAD therapy in contemporary era. Given durability of heart transplantation, strategies should be developed to promote weight loss, which occurs infrequently in obese patients. Impact of weight loss on clinical outcome of obese patients warrants further investigation

Topical versus Systemic Vancomycin for Deep Sternal Wound Infection Caused by Methicillin-Resistant Staphylococcus aureus in a Rodent Experimental Model

In 37 Wistar albino rats, we investigated the effects of topical vancomycin on deep sternal wound infection caused by methicillin-resistant Staphylococcus aureus. Partial median sternotomy was performed under sterile conditions. Group I (n=6) was the sham, and group II (n=7) was the control. Group III (n=8) received topical vancomycin, group IV (n=8) received systemic vancomycin, and group V (n=8) received topical and systemic vancomycin (combined). Rats in groups II through V were inoculated with 0.5 mL × 10(8) CFU/mL methicillin-resistant S. aureus in the mediastinum and sternum. No medication was given to groups I and II. Twenty-four hours after surgery, 40 mg/kg/day vancomycin was given topically in group III; systemically in group IV; and topically and systemically in group V. After 7 days, smear samples from the mediastinum and tissue cultures from the sternum were obtained. We found 5.00 ± 0 CFU/mL microorganisms in the mediastinum in group II, 1.90 ± 1.70 in group III, 3.33 ± 0.48 in group IV, and 1.70 ± 1.08 in group V. The quantity of microorganisms per gram of tissue in the sternum was 7.36 ± 0.23 in group II, 6.01 ± 0.33 in group III, 5.81 ± 0.81 in group IV, and 3.99 ± 2.47 in group V. The quantity of microorganisms was less in the 3 treatment groups than in the control group (P <0.05). We conclude that topical plus systemic vancomycin treatment might be more effective in patients with deep sternal wound infections caused by methicillin-resistant S. aureus

Role of hyperbaric oxygen therapy in the treatment of postoperative organ/space sternal surgical site infections

BACKGROUND: A prospective trial was designed to evaluate the effect of hyperbaric oxygen (HBO) therapy on organ/space sternal surgical site infections (SSIs) following cardiac surgery that requires sternotomy. METHODS: A total of 32 patients who developed postoperative organ/space sternal SSI were enrolled in this study from 1999 through 2005. All patients were offered HBO therapy. Group 1 included the patients who accepted and were able to undergo HBO therapy (n = 14); group 2 included patients who refused HBO therapy or had contraindications to it (n = 18). RESULTS: The two groups were well matched at baseline with comparable preoperative clinical characteristics and operative factors. Staphylococcus was the most common pathogen for both groups. The duration of infection was similar in groups 1 and 2 (31.8 7.6 vs. 29.3 5.7 days, respectively, p = 0.357). The infection relapse rate was significantly lower in group 1 (0% vs. 33.3%, p = 0.024). Moreover, the duration of intravenous antibiotic use (47.8 +/- 7.4 vs. 67.6 +/- 25.1 days, p = 0.036) and total hospital stay (52.6 +/- 9.1 vs. 73.6 +/- 24.5 days, p = 0.026) were both significantly shorter in group 1. CONCLUSION: Hyperbaric oxygen is a valuable addition to the armamentarium available to physicians for treating postoperative organ/space sternal SSI