Obesity and left ventricular assist device driveline exit site infection

Clinical outcomes of modified left ventricular assist device driveline management

Left ventricular assist devices (LVADs) are implanted in patients with heart failure to support cardiac circulation. However, no standardized methods have been established for LVAD driveline exit site management for the prevention of infections. Therefore, this study evaluated the efficacy of modified driveline management compared with that of conventional driveline management. We retrospectively assessed the outcomes of 262 patients who underwent continuous-flow LVAD implantation between January 2005 and March 2023 at Osaka University in Japan. In conventional driveline management, an LVAD driveline penetrates the skin along the body surface and is fixed near the penetration site (n = 224). In contrast, in our modified fixation method, the LVAD driveline vertically penetrates the skin to prevent ischemia at the driveline exit site and is fixed at a distant abdominal site to prevent the movement of the driveline exit site due to body movement (n = 38). The rates of freedom from LVAD driveline infection in patients with conventional driveline management were 86, 75, and 63% at 1, 2, and 3 years after LVAD implantation, respectively. The rate of freedom from LVAD driveline infection in patients managed by the modified fixation method was 91% at 1, 2, as well as 3 years after LVAD implantation. The freedom rates from LVAD driveline infection in the patients with modified fixation method was lower than in the patients with the conventional method (p = 0.04). Our study revealed that the modified fixation method may offer the possibility for preventing LVAD driveline infection.

Epidemiology and impact of device-specific infections on patients receiving left ventricular assist devices

Background

Left ventricular assist device-specific infections (LSIs) remain a persistent problem facing patients with durable left-ventricular assist devices (LVADs). However, the infectious agents and associated morbidity remained poorly defined. We sought to evaluate the incidence, epidemiology, and morbidity associated with LSIs in patients receiving modern centrifugal LVADs at 2 tertiary care centers.

Methods

Retrospective analysis was performed of adult patients receiving HeartMate 3 implants at the University of Pennsylvania and Mount Sinai Health Systems from January 1, 2015 to March 31, 2021, with follow-up until March 31, 2022. Patients were grouped by history of LSI, defined as culture-positive infections and/or those requiring medical or surgical intervention. Demographic data, available culture data, medical interventions, and surgical interventions were queried. Survival analysis was censored at 4 years and landmarked according to 25th percentile time-to-infection.

Results

Among 206 LVAD recipients, 71 (34.5%) developed an LSI. Predominant organisms were Staphylococcus (47.9%), Pseudomonas (15.5%), and Serratia (8.5%). Predictors of infection included Black race (LSI vs No LSI: 46.2% vs 29.2%, p = 0.021) and body mass index (median 29.7 vs 26.2 kg/m2, p = 0.007). Median time to infection was 231 days (112-423), with 19 (26.8%) patients requiring surgical debridement. Landmarked survival did not differ (log-rank p = 0.830). LSI patients were hospitalized an extra 8 (0-28) days for infection-related reasons.

Conclusion

LSIs remain pervasive, with most related to Staphylococcus, Pseudomonas, and Serratia, and are associated with significantly increased rehospitalization burden. Surgical interventions were utilized in 26.8% of patients. Continued efforts to understand and prevent LSIs are necessary to improve care for LVAD patients.

Infections in Patients with Mechanical Circulatory Support

Patients on mechanical circulatory support are at heightened risk for infection given the invasive nature of the devices with internal and external components, the surgical implantation of the devices, and the presence of foreign material susceptible to biofilm formation. This review discusses the new International Society for Heart and Lung Transplantation mechanical circulatory support device infection definitions, inclusive of durable and acute mechanical circulatory support infections, and describes their epidemiology, diagnosis, and management. A multidisciplinary approach is essential for optimal management. Timing of transplantation in the context of active infection is addressed, and areas of future research are highlighted.

Value of nutritional indices in predicting survival free from pump replacement and driveline infections in centrifugal left ventricular assist devices

Objective

There is a paucity of data assessing the impact of nutritional status on outcomes in patients supported with the HeartMate 3 (HM3) left ventricular assist device (LVAD).

Methods

Patients ≥18 years of age who underwent HM3 LVAD implantation between 2015 and 2020 were identified from a single tertiary care center. The primary outcome assessed was death or device replacement. A secondary outcome of driveline infection was also evaluated. Kaplan-Meier survival analysis and a multivariate Cox-proportional hazards model were used to identify predictors of outcome.

Results

Of the 289 patients identified, 94 (33%) experienced a primary outcome and 96 (33%) a secondary outcome during a median follow-up time of 2.3 years. Independent predictors of the primary outcome included peripheral vascular disease (hazard ratio [HR], 3.40; 95% confidence interval [CI], 1.66-6.97, P < .01), diabetes mellitus (HR, 0.46; 95% CI, 0.27-0.80, P < .01), body mass index ≥40 kg/m2 (HR, 2.63 per 1 kg/m2 increase; 95% CI, 1.22-5.70, P < .05), preoperative creatinine level (HR, 1.86 per 1 mg/dL increase; 95% CI, 1.31-2.65, P < .01), and preoperative prognostic nutritional index (PNI) score (HR, 0.88 per 1-point increase; 95% CI, 0.81-0.96, P < .01). Independent predictors of driveline infection included age at the time of implantation (HR, 0.97; 95% CI, 0.96-0.99, P < .01) and diabetes mellitus (HR, 1.79; 95% CI, 1.17-2.73, P < .01).

Conclusions

Preoperative PNI scores may independently predict mortality and the need for device replacement in patients with HM3 LVAD. Routine use of the PNI score during preoperative evaluation and, when possible, supplementation to PNI >33, may be of value in this population.

Driveline infections in left ventricular assist devices-Incidence, epidemiology, and staging proposal

BACKGROUND

Driveline infections (DLI) are a serious complication in patients with left ventricular assist devices (LVAD). Apart from the differentiation between superficial and deep DLI, there is no consensus on the classification of the severity of DLI. Little is known about risk factors and typical bacteria causing DLI in centrifugal-flow LVADs.

METHODS

In this single-center study with 245 patients, DLI were classified by their local appearance using a modification of a score suggested by the Sharp Memorial group. The driveline exit site was inspected routinely every 6 months.

RESULTS

Severe DLI were detected in 34 patients (15%) after 6 months and in 24 patients (22%) after 24 months. The proportion of patients with DLI increased significantly during the follow-up (p = 0.0096). The most common bacteria in local smears were Corynebacterium, coagulase-negative Staphylococcus, and Staphylococcus aureus. Fifty-nine patients were hospitalized more than once for DLI. In these patients, S. aureus was the most common bacterium. It was also the most common bacterium in blood cultures. Higher BMI, no partnership, and a HeartMate 3 device were identified as risk factors for DLI in a multivariable cause-specific Cox regression.

CONCLUSION

This study is a standardized analysis of DLI in a large cohort with centrifugal-flow LVADs.

Body mass index-dependent immunological profile changes after left ventricular assist device implantation

Purpose

Infection is a common complication following left ventricular assist device (LVAD) implantation. Patients with obesity are particularly at risk due to their high percentage of adipose tissue and the resulting chronic inflammatory state and resulting immunological changes. This study investigated changes of immunological parameters in relation to body mass index (BMI) during the first year after LVAD implantation.

Methods

Blood samples were obtained prior to LVAD implantation and at 3 (1st FU), 6 (2nd FU) and 12 mo (3rd FU) after LVAD implantation. Patients were divided into three groups (normal weight: BMI of 18.5-24.9 kg/m2; n=12; pre-obesity: 25.0-29.9 kg/m2; n=15; obesity: ≥ 30.0 kg/m2; n=17) based on their BMI at the time of LVAD implantation. Flow cytometric analyses for CD4+ and CD8+ T cells, regulatory T cells (Tregs), B cells as well as dendritic cells (DCs) were performed.

Results

After LVAD implantation, obese patients (0.51 ± 0.20%) showed a higher proportion of overall DCs than normal-weight (0.28 ± 0.10%) and pre-obese patients (0.32 ± 0.11%, p<0.01) at 3rd FU. The proportion of BDCA3+ myeloid DCs was lower in obese patients (64.3 ± 26.5%) compared to normal-weight patients (82.7 ± 10.0%, pnormal-weight vs. obesity=0.05) at 2nd FU after LVAD implantation. The analysis of BDCA4+ plasmacytoid DCs revealed a reduced proportion in pre-obese (21.1 ± 9.8%, pnormal-weight vs. pre-obesity=0.01) and obese patients (23.7 ± 10.6%, pnormal-weight vs. obesity=0.05) compared to normal-weight patients (33.1 ± 8.2%) in the 1st FU. T cell analysis showed that CD4+ T cells of obese patients (62.4 ± 9.0%) significantly increased in comparison to pre-obese patients (52.7 ± 10.0%, ppre-obesity vs. obesity=0.05) and CD8+ T cells were lower in obese patients (31.8 ± 8.5%) than in normal-weight patients (42.4 ± 14.2%; pnormal-weight vs. obesity=0.04) at the 3rd FU. Furthermore, we observed significantly reduced proportions of Tregs in pre-obese patients compared to normal-weight and obese patients at 2nd FU (p=0.02) and 3rd FU (p=0.01) after LVAD implantation.

Conclusion

This study reported changes of the innate and adaptive immune system of pre-obese and obese compared to normal-weight patients one year after LVAD implantation. DCs and their subsets, CD8+ T cells and Tregs were affected immune cell populations that indicate immunological changes which might increase the incidence of postoperative infection.

Infections in Patients With Left Ventricular Assist Devices: Current State and Future Perspectives

Mechanical circulatory support is increasingly being used as bridge-to-transplant and destination therapy in patients with advanced heart failure. Technologic improvements have led to increased patient survival and quality of life, but infection remains one of the leading adverse events following ventricular assist device (VAD) implantation. Infections can be classified as VAD-specific, VAD-related, and non-VAD infections. Risk of VAD-specific infections, such as driveline, pump pocket, and pump infections, remains for the duration of implantation. While adverse events are typically most common early (within 90 days of implantation), device-specific infection (primarily driveline) is a notable exception. No diminishment over time is seen, with event rates of 0.16 events per patient-year in both the early and late periods postimplantation. Management of VAD-specific infections requires aggressive treatment and chronic suppressive antimicrobial therapy is indicated when there is concern for seeding of the device. While surgical intervention/hardware removal is often necessary in prosthesis-related infections, this is not so easily accomplished with VADs. This review outlines the current state of infections in patients supported with VAD therapy and discusses future directions, including possibilities with fully implantable devices and novel approaches to treatment.

Nontuberculous Mycobacterial Infections Associated With Left Ventricular Assist Devices in 3 Patients

Durable left ventricular assist devices (LVADs) provide circulatory support in patients with end-stage heart failure; however, complications include infection of the driveline exit site. Nontuberculous mycobacterial infections are rare in patients with LVADs, but they should be considered in those who have undergone device exchanges and have bacterial infections with driveline exit-site discharge but no fever or leukocytosis. We reviewed the charts of patients who had an LVAD implanted at our institution from January 2009 through December 2019, to identify those with a device-related nontuberculous mycobacterial infection. Collected data included patient demographics, premorbid conditions, infection type, previous device complications, treatment, and outcomes. We identified infections in 3 patients (mean age, 41 yr): Mycobacterium abscessus in 2 and M. chimaera in 1. All had a HeartMate II device and had undergone device exchanges for pump thrombosis or for driveline fault or infections. All presented with driveline exit-site discharge without fever or leukocytosis. The mean time between initial device implantation and diagnosis of a nontuberculous mycobacterial infection was 55 months. All 3 patients were treated with antibiotics and underwent localized surgical débridement; one underwent an additional device exchange. The M. abscessus infections disseminated, and both patients died; the patient with M. chimaera infection continued to take suppressive antibiotics. Nontuberculous mycobacterial infections are associated with high morbidity and mortality rates, warranting prompt diagnosis and treatment.

Decreasing driveline infections in patients supported on ventricular assist devices: a care pathway approach

Background

Driveline infections (DLIs) are a common adverse event in patients on ventricular assist devices (VADs) with incidence ranging from 14% to 59%. DLIs have an impact on patients and the healthcare system with efforts to prevent DLIs being essential. Prior to our intervention, our program had no standard driveline management presurgery and postsurgery. The purpose of this Quality Improvement (QI) initiative was to reduce DLIs and related admissions among patients with VAD within the first year post implant.

Methods

In anticipation of the QI project, we undertook a review of the programs’ current driveline management procedures and completed a survey with patients with VAD to identify current barriers to proper driveline management. Retrospective data were collected for a pre-QI intervention baseline comparison group, which included adult patients implanted with a durable VAD between 1 January 2017 and 31 July 2018. A three-pronged care pathway (CP) was initiated among patients implanted during August 2018 to July 2019. The CP included standardised intraoperative, postoperative and predischarge teaching initiatives and tracking. Using statistical process control methods, DLIs and readmissions in the first year post implant were compared between patients in the CP group and non-CP patients. P-charts were used to detect special cause variation.

Results

A higher proportion of CP group patients developed a DLI in the first year after implant (52% vs 32%). None developed a DLI during the index admission, which differed from the non-CP group and met criteria for special cause variation. There was a downward trend in cumulative DLI-related readmissions among CP group patients (55% vs 67%). There was no association between CP compliance and development of DLIs within 1 year post implant.

Conclusion

The CP did not lead to a reduction in the incidence of DLIs but there was a decrease in the proportion of patients with DLIs during their index admission and those readmitted for DLIs within 1 year post implant. This suggests that the CP played a role in decreasing the impact of DLIs in this patient population. However, given the short time period of follow-up longer follow-up will be required to look for sustained effects.

Mechanical Circulatory Support as a Bridge-to-Transplant Candidacy: When Does It Work?

Durable mechanical circulatory support (dMCS) devices can be offered as a bridge-to-transplant (BTT) or as a bridge-to-candidacy (BTC) strategy for candidates with contraindications to transplant listing, including pulmonary hypertension (BTC-PH), morbid obesity (BTC-Obes), social issues (BTC-Soc), or chronic illness (BTC-Illness). An understanding of the trajectory of BTC patients could guide future triage of advanced heart failure patients who are not candidates for transplantation. We performed a retrospective review all patients who underwent dMCS implantation as either BTT (206 patients) or BTC (114 patients) at our center from January 1, 2010, to March 31, 2020. There was no significant difference in mortality between BTC patients and BTT patients. Compared with the BTT group, significantly more patients in the BTC-PH group were transplanted (81% vs. 63%; p < 0.05) and significantly fewer patients in the BTC-Obes group (44%; p < 0.05) and BTC-Soc group (39%; p < 0.05) were transplanted. Additionally, the readmission rate was higher for those in the BTC-Obes (6.2 vs. 2.1; p < 0.05) and BTC-Soc (3.9 vs. 2.1; p < 0.05) groups. Bridge-to-candidacy patients generally had poorer post-dMCS trajectories than BTT patients. Centers should not be dissuaded from pursuing a BTC strategy for qualified patients; however, careful consideration of potential adverse outcomes is necessary.

Fatigue in Persons With Heart Failure: A Systematic Literature Review and Meta-Synthesis Using the Biopsychosocial Model of Health

BACKGROUND

Fatigue is a common and distressing symptom of heart failure (HF) and has important implications for patient-reported and clinical outcomes. Despite being a common and bothersome symptom, fatigue has been understudied in HF. We sought to synthesize existing literature on fatigue in HF through a systematic literature review guided by the biopsychosocial model of health.

METHODS AND RESULTS

A systematic search of the literature was performed on March 18, 2020, using Pubmed, Embase, and CINAHL. Full-text, primary research articles, written in English, in which fatigue was a primary symptom of interest in adults with a diagnosis of HF, were included. The search yielded 1138 articles; 33 articles that met inclusion criteria were selected for extraction and synthesis. Biological and psychological factors associated with fatigue were New York Heart Association functional class, hemoglobin level, history of stroke, and depression. However, there are limited HF-specific factors linked to fatigue. Social factors related to fatigue included social roles, relationship strain, and loneliness and isolation. Few nonpharmacologic interventions have been tested by show some promise for alleviating fatigue in HF. Studies show conflicting evidence related to the prognostic implications of fatigue.

CONCLUSIONS

Important biological correlates of fatigue were identified; however, psychological and social variables were limited to qualitative description. There is need for expanded models to better understand the complex physiologic nature of fatigue in HF. Additionally, more research is needed to (1) define the relationships between fatigue and both psychological and social factors, (2) better describe the prognostic implications of fatigue, and (3) develop more therapeutic approaches to alleviate fatigue with the goal of improving overall quality of life.

Ventricular Assist Device Driveline Infections: A Systematic Review

Infection is the most common complication in patients undergoing ventricular assist device (VAD) implantation. Driveline exit site (DLES) infection is the most frequent VAD infection and is a significant cause of adverse events in VAD patients, contributing to morbidity, even mortality, and repetitive hospital readmissions. There are many risk factors for driveline infection (DLI) including younger age, smaller constitution of patients, obesity, exposed velour at the DLES, longer duration of device support, lower cardiac index, higher heart failure score, DLES trauma, and comorbidities such as diabetes mellitus, chronic kidney disease, and depression. The incidence of DLI depends also on the device type. Numerous measures to prevent DLI currently exist. Some of them are proven, whereas the others remain controversial. Current recommendations on DLES care and DLI management are predominantly based on expert consensus and clinical experience of the certain centers. However, careful and uniform DLES care including obligatory driveline immobilization, previously prepared sterile dressing change kits, and continuous patient education are probably crucial for prevention of DLI. Diagnosis and treatment of DLI are often challenging because of certain immunological alterations in VAD patients and microbial biofilm formation on the driveline surface areas. Although there are many conservative and surgical methods described in the DLI treatment, the only possible permanent solution for DLI resolution in VAD patients is heart transplantation. This systematic review brings a comprehensive synthesis of recent data on the prevention, diagnostic workup, and conservative and surgical management of DLI in VAD patients.

Outcomes in patients with smaller body surface area after HeartMate 3 left ventricular assist device implantation

BACKGROUND

Due to anatomic and physiologic concerns, prior generations of the left ventricular assist devices (LVAD) have frequently been denied to patients with small body size. However, outcomes in patients with small body surface area (BSA) following HeartMate 3 (HM3) LVAD implantation remain relatively unknown.

METHODS

A cohort of 220 patients implanted at a single center was divided into two groups: BSA ≤1.8 m² (small BSA, n = 37) and BSA >1.8 m² (large BSA, n = 183). We investigated baseline characteristics and clinical outcomes including survival and incidence of adverse events.

RESULTS

Small BSA patients were older (60 vs. 57 years), more likely female (60% vs. 20%), had a lower body mass index (24 vs. 32 kg/m² ), lower incidence of diabetes (32% vs. 51%), history of stroke (5% vs. 19%), and left ventricular thrombus (0% vs. 11%). They had smaller left ventricular end diastolic diameter (64.8 vs. 69.3 mm). Pump speed and pump flows at discharge were lower in the small BSA group. Survival at 1 year and 2 years was 86% versus 87% and 86% versus 79% for small versus large BSA groups (p = 0.408), respectively. The rates of adverse events were similar between groups and there were no cases of confirmed pump thrombosis. The incidence of readmissions for low flow alarms was higher in the small BSA group (0.55 vs. 0.24 EPPY).

CONCLUSIONS

These findings demonstrate comparable outcomes in patients with small body size and suggest that this parameter should not be an exclusion criterion on patients who are otherwise candidates for HM3 LVAD implantation.

Left ventricular assist device driveline infections in three contemporary devices

Driveline infections (DLI) are common adverse events in left ventricular assist devices (LVADs), leading to severe complications and readmissions. The study aims to characterize risk factors for DLI readmission 2 years postimplant. This single‐center study included 183 LVAD patients (43 HeartMate II [HMII], 29 HeartMate 3 [HM3], 111 HVAD) following hospital discharge between 2013 and 2017. Demographics, clinical parameters, and outcomes were retrospectively analyzed and 12.6% of patients were readmitted for DLI, 14.8% experienced DLI but were treated in the outpatient setting, and 72.7% had no DLI. Mean C‐reactive protein (CRP), leukocytes and fibrinogen were higher in patients with DLI readmission (P < .02) than in outpatient DLI and patients without DLI, as early as 60 days before readmission. Freedom from DLI readmission was comparable for HMII and HVAD (98% vs. 87%; HR, 4.52; 95% CI, 0.58‐35.02; P = .15) but significantly lower for HM3 (72%; HR, 10.82; 95% CI, 1.26‐92.68; P = .03). DLI (HR, 1.001; 95% CI, 0.999‐1.002; P = .16) or device type had no effect on mortality. DLI readmission remains a serious problem following LVAD implantation, where CRP, leukocytes, and fibrinogen might serve as risk factors already 60 days before. HM3 patients had a higher risk for DLI readmissions compared to HVAD or HMII, possibly because of device‐specific driveline differences.

Percutaneous Ventricular Assist Device vs. Intra-Aortic Balloon Pump for Hemodynamic Support in Acute Myocardial Infarction-Related Cardiogenic Shock and Coexistent Atrial Fibrillation: A Nationwide Propensity-Matched Analysis'

BACKGROUND

Patients suffering an acute myocardial infarction complicated by cardiogenic shock (AMICS) may experience clinical deterioration with concomitant atrial fibrillation (AF). Recent data suggest that percutaneous ventricular assist devices (pVADs) provide superior hemodynamic support over intra-aortic balloon pump (IABP) in AMICS. In patients with AF+AMICS, however, outcomes data comparing these two devices remain limited.

METHODS

Using the National Inpatient Sample datasets (2008-2014) and a propensity-score matched analysis, we compared the outcomes of AMICS+AF hospitalized patients undergoing PCI with pVAD vs. IABP support.

RESULTS

A total of 12,842 AMICS+AF patients were identified (pVAD=468, IABP=12,374). The matched groups (pVAD=443, IABP=443) were comparable in terms of mean age (70.3 ± 12.0 vs. 70.4 ± 11.0yrs, p = 0.92). The utilization of pVAD was higher in whites but lower in Medicare/Medicaid beneficiaries as compared to IABP. The pVAD group demonstrated higher rates of obesity (13.6% vs. 7.8%, p = 0.006) and dyslipidemia (48.4% vs. 41.8%, p = 0.05). There was no difference in the in-hospital mortality (40.5% vs. 36.8%, p = 0.25); however, pVAD group had a lower incidence of post-procedural MI and higher incidences of stroke (7.8% vs. 4.4%, p = 0.03), hemorrhage (5.6% vs. 2.3%, p = 0.01), discharges to home health care (13.5% vs. 10.1%, p<0.001) and to other facilities (29.1% vs. 24.9%, p<0.001) as compared to IABP group. There was no difference between the groups in terms of mean length of stay or hospital charges.

CONCLUSIONS

All-cause inpatient mortality was similar in AMICS+AF patients undergoing PCI who were treated with either pVAD or IABP. The pVAD group, however, experienced more complications while consuming greater healthcare resources.

Bloodstream Infections in Continuous Flow Left Ventricular Assist Device Recipients: Diagnostic and Clinical Implications

Bloodstream infection (BSI) is a common complication of left ventricular assist device (LVAD) support and particularly difficult to treat. The presentation is often variable because of altered physiology and augmentation of cardiac output by the device. We studied LVAD recipients at a single institution. Multivariate logistic and Cox (with time-varying parameters) regression were implemented. Of 212 patients, 58% experienced infections. Driveline infection (DLI) affected 31%, with 60% of them having deep-tissue involvement. Sixty-six patients (31%) suffered from 135 BSIs. Systemic inflammatory response syndrome (SIRS) was present in 47% of BSIs at presentation and associated with increased mortality. Right heart failure, destination therapy, Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile, morbid obesity, and deep-DLI were independent risk factors for BSI. The BSI was independently associated with mortality. Bridge-to-transplantation (BTT) patients were more likely to receive transplant if they did not have BSIs. Among 104 BTT patients who received heart transplantation, development of BSI was associated with shorter time-to-transplantation. Diagnosis of BSI poses diagnostic and prognostic challenges because of the hemodynamic profile of LVAD patients who may not mount the expected physiologic response to sepsis. Although SIRS criteria lack sensitivity in the LVAD population, SIRS signifies increased risk for death. Deep DLI was the strongest predictor of BSI. Despite the upgrade in listing status of BTT-LVADs with BSIs and shorter time-to-transplantation, BSI remain a major cause of mortality. BSIs are associated with significant mortality and should be regarded as a serious complication, similar to pump thrombosis and stroke.

Left ventricular assist device-associated infections: incidence and risk factors

Background

Left ventricular assist device (LVAD)-associated infections are major complications that can lead to critical outcomes. The aims of this study were to assess the incidence of and to determine the risk factors for LVAD-associated infections.

Methods

We included all consecutive patients undergoing LVAD implantation between January 1, 2010, and January 1, 2019, in a single institution. Infection-related data were retrospectively collected by review of patient's medical files. LVAD-associated infections were classified into three categories: percutaneous driveline infections, pocket infections and pump and/or cannula infections.

Results

We enrolled 72 patients. Twenty-one (29.2%) patients presented a total of 32 LVAD-associated infections. Eight (38.1%) patients had more than one infection. Five (62.5%) pocket infections and one (50.0%) pump and/or cannula infection were preceded by a driveline infection. The median delay between the operation and LVAD-associated infection was 6.5 (1.4-12.4) months. The probability of having a LVAD-associated infection at one year after receiving an implant was 26.6% (95% CI: 17.5-40.5%). Percutaneous driveline infections represented 68.7% of all LVAD-associated infections. Staphylococcus aureus and coagulase-negative staphylococci were the predominant bacteria in LVAD-associated infections (53.1% and 15.6%, respectively). Hospital length of stay (sdHR =1.22 per 10 days; P=0.001) and postoperative hemodialysis (sdHR =0.17; P=0.004) were statistically associated with infection. Colonization with multidrug-resistant bacteria was more frequent in patients with LVAD-associated infections than in others patients (42.9% vs. 15.7%; P=0.013).

Conclusions

LVAD-associated infections remain an important complication and are mostly represented by percutaneous driveline infections. Gram-positive cocci are the main pathogens isolated in microbiological samples. Patients with LVAD-associated infections are more frequently colonized with multidrug-resistant bacteria.

In Full Flow: Left Ventricular Assist Device Infections in the Modern Era

With the rising prevalence of heart disease in the United States, there is increasing reliance on durable mechanical circulatory support (MCS) to treat patients with end-stage heart failure. Left ventricular assist devices (LVADs), the most common form of durable MCS, are implanted mechanical pumps that connect to an external power source through a transcutaneous driveline. First-generation LVADs were bulky, pulsatile pumps that were frequently complicated by infection. Second-generation LVADs have an improved design, though infection remains a common and serious complication due to the inherent nature of implanted MCS. Infections can affect any component of the LVAD, with driveline infections being the most common. LVAD infections carry significant morbidity and mortality for LVAD patients. Therefore, it is paramount for the multidisciplinary team of clinicians caring for these patients to be familiar with this complication. We review the epidemiology, prevention, diagnosis, treatment, and outcomes of LVAD infections.

Weight evolution after implantation of left ventricular assist device: Do we need to interfere?

OBJECTIVES

Weight change after left ventricular assist device implantation may influence outcomes and can affect transplant candidacy. We questioned if there is a systematic weight change after left ventricular assist device implantation and examined the evolution in functional capacity.

METHODS

A retrospective analysis of 84 patients who received a left ventricular assist device in Universitaire Ziekenhuizen Leuven between 2008 and 2016 was performed. Patients were divided into four groups based on their baseline body mass index, and we also examined weight evolution for patients presenting with new-onset heart failure versus those suffering from chronic heart failure. Body mass index was assessed at baseline, 6, 12, 18, and 24 months. To indicate the functional capacity, we analyzed the results of routine 6-Minute Walk Test performed at 6, 12, and 18 months.

RESULTS

During the first 6 months after surgery, the underweight patients evolved to normal weight and the body mass index of the obese patients reduced significantly. Afterward, all patients gained weight. The weight loss of the obese was not maintained over time. The weight of patients with normal weight and overweight evolved to overweight and obesity, respectively. No body mass index changes were demonstrated for patients presenting with new-onset heart failure, and the body mass index of patients suffering from chronic HF significantly increased. There was a significant improvement in functional capacity at 6 months, but this level remained unchanged at 12 and 18 months after surgery.

CONCLUSION

Although the initial 6 months evolve beneficial, all patients gain weight in the second year and do not further improve their exercise capacity.

Durable left ventricular assist device support as a bridge to heart transplant candidacy†

OBJECTIVES

Left ventricular assist devices are funded in the UK exclusively as a bridge to transplant (BTT). However, patients who potentially could receive a transplant may develop reversible contraindications to transplant. Bridge to candidacy (BTC) has sometimes been controversial, given the uncertain clinical efficacy of BTC and the risk that reimbursement could be denied. We analysed the UK ventricular assist device database to understand how common BTC was and to assess patient survival rates and incidences of transplants.

METHODS

We identified BTC implants in patients with pulmonary hypertension, chronic kidney disease and obesity using the UK guidelines for heart transplants.

RESULTS

A total of 306 of 540 patients had complete data and 157 were identified as BTC (51%). Overall, there was no difference in survival rates between patients designated as BTC and those designated at BTT (71.9 vs 72.9% at 1 year, respectively; P = 0.82). However, the survival rate was lower at all time points in those with an estimated glomerular filtration rate (eGFR) <40 and in patients with a body mass index (BMI) >32 up to 1-year postimplant. There were no significant differences in the incidence of transplant between patients who were BTC and BTT or for any subgroup up to 5 years. However, we noted a diverging trend towards a lower cumulative incidence of transplant for patients with a BMI >32.

CONCLUSIONS

BTC is common in the UK and appears clinically effective, given that the survival rates and the incidence of transplants were comparable with those for BTT. Patients with a high BMI have a worse survival rate through to 1 year and a trend for a lower incidence of a transplant. Patients with a low eGFR also have a worse survival rate, but a similar proportion received transplants.

Impact of Obesity on Ventricular Assist Device Outcomes

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.

Human Factors and User Experience Issues with Ventricular Assist Device Wearable Components: A Systematic Review

Ventricular Assist Devices (VADs) provide continuous mechanical circulatory support during in- and out-of-hospital care. However, limitations of the external wearable components influence patient quality of life. There is insufficient understanding of the issues with such components that combines a holistic viewpoint from both human factors and user (including patient and caregiver) experience perspectives. This paper comprehensively details the issues with VAD wearable systems and proposes a way for human-centered design to bridge the gap, addressing such issues synergistically. Through the review the authors investigated: the user issues caused by wearable components of VADs, and how human factors issues correlate to the VAD user experience. A Boolean search ("ventricular assist" AND "human factors" AND "experience") for peer-reviewed studies published between 2008 and 2018 returned 338 titles, with 35 relevant studies selected using a PRISMA process for inclusion in cross-study analysis and synthesis. This paper provides design recommendations for the issues found in the literature. Four key focus areas to inform the future design of VAD wearable components were identified-'Power Supply', 'Wearability and Travel Freedom', 'The Female Experience' and 'Intuitive Handling'. Using design to drive innovation could result in VAD wearable components which better meet or exceed users' quality of life goals.

Single versus multi-drug antimicrobial surgical infection prophylaxis for left ventricular assist devices: A systematic review and meta-analysis

Infection remains the Achilles heel of left ventricular assist device (LVAD) therapy. However, an optimal antimicrobial surgical infection prophylaxis (SIP) regimen has not been established. This study evaluated the efficacy of a single-drug SIP compared to a multi-drug SIP on clinical outcomes in patients undergoing continuous-flow LVAD (CF-LVAD) and pulsatile LVAD (P-LVAD) implantation. An electronic search was performed to identify studies in the English literature on SIP regimens in patients undergoing LVAD implantation. Identified articles were assessed for inclusion and exclusion criteria. Fourteen articles with 1,311 (CF-LVAD: 888; P-LVAD: 423) patients were analyzed. Overall, 501 (38.0%) patients received single-drug SIP, whereas 810 (62.0%) received multi-drug SIP. Time to infection was comparable between groups. There was no significant difference in overall incidence of LVAD-specific infections [single-drug: 18.7% vs. multi-drug: 24.8%, P = 0.49] including driveline infections [single-drug: 14.1% vs. multi-drug: 20.8%, P = 0.37]. Compared to single-drug SIP, patients who received multi-drug SIP had a significantly lower survival rate [single-drug: 90.0% vs. multi-drug: 76.0%, P = 0.01] and infection-free survival rate [single-drug: 88.4% vs. multi-drug: 77.3%, P = 0.04] at 90 days. However, there were no significant differences in 1-year survival and 1-year infection-free survival between groups. No survival differences were observed in the CF-LVAD subset as well. This study demonstrated no additional advantage of a multi-drug compared to a single-drug regimen for SIP. Although there was a modest advantage in early survival among CF-LVAD and P-LVAD patients who received single-drug SIP, there were no significant differences in the 1-year survival and 1-year infection-free survival.

Driveline Site Is Not a Predictor of Infection After Ventricular Assist Device Implantation

Driveline infections (DLIs) remain a major source of morbidity for patients requiring long-term ventricular assist device (VAD) support. We aimed to assess whether VAD driveline exit site (DLES) (abdomen versus chest wall) is associated with DLI. All adult patients who underwent insertion of a HeartWare HVAD or HeartMate II (HMII) between 2009 and 2016 were included. Driveline infection was defined as clinical evidence of DLI accompanied by a positive bacterial swab and need for antibiotics. Competing risks analysis was used to assess the association between patient characteristics and DLI. Ninety-two devices (59 HMII) were implanted in 85 patients (72 men; median age 57.4 years) for bridge to transplant or destination therapy. VAD DLES was chest in 28 (30.4%) devices. Median time on VAD support was 347.5 days (IQR 145.5, 757.5), with 28 transplants and 29 deaths (27 on device). DLI occurred in 24 patients (25 devices) at a median of 140 days (IQR 67, 314) from implant. Staphylococcus aureus accounted for 15 infections (60%). Freedom from infection was 72.8% (95% confidence interval [CI] 53.1-78.0%) at 1 year and 41.9% (95% CI 21.1-61.5%) at 3 years. In competing risks regression, abdominal DLES was not predictive of DLI (hazard ratio, HR 1.65 [95% CI 0.63, 4.29]), but body mass index (BMI) >30 kg/m was (HR 2.72 [95% CI 1.25, 5.92]). In conclusion, risk of DLI is high among patients on long-term VAD support, and a nonabdominal DLES does not reduce this risk. The only predictor of DLI in this series was an elevated BMI.

Risk of left ventricular assist device driveline infection: A systematic literature review

BACKGROUND

Left ventricular assist devices (LVADs) improve quality of life in end-stage heart failure but can cause serious complications such as infections with driveline infection causing significant morbidity and mortality.

OBJECTIVES

The purpose of this systematic literature review is to synthesize the literature to determine variables associated with driveline infection and seek opportunities to improve nursing management of LVAD drivelines.

METHODS

A systematic literature review was performed. The evidence was synthesized using the Johns Hopkins Nursing Evidence-Based Practice tools and the Chain of Infection epidemiological framework.

RESULTS

Thirty-four studies focused on vulnerable host, portal of entry, and causative organism aspects of the Chain of Infection. Increased BMI, younger age, exposed driveline velour showed increased risk of infection and driveline dressing protocol change showed lower risk of infection.

CONCLUSIONS

Although some risk factors for infection were identified, evidence is still limited. Nurses are uniquely positioned to improve driveline management, disrupting the chain of infection.

Obesity in patients with end-stage heart failure

Obesity poses an increasing problem in patients with end-stage heart failure (HF). The most commonly used indicator of obesity is body mass index. The value of this parameter is widely taken into consideration when selecting the best way of treatment for patients with advanced HF. The aim of this paper is to outline the recent knowledge about obesity in the abovementioned group of patients.

The impact of infection among left ventricular assist device recipients on post-transplantation outcomes: A retrospective review

INTRODUCTION

Left ventricular assist device (LVAD) infections are common, and the consequences of LVAD infections on orthotopic heart transplantation (OHT) outcomes are not well described.

AIMS

The aim of this study was to describe clinical characteristics and evaluate risk factors for developing LVAD infections, and examine outcomes of LVAD-specific infections (VSI) after OHT.

METHODS

We retrospectively investigated the records of 74 consecutive patients at two institutions who had undergone LVAD placement and subsequent OHT between January 2007 and December 2012.

RESULTS

Forty-six of 74 (62%) LVAD recipients who underwent OHT had pre-transplant infections, and 18 (24%) had LVAD-specific infection (VSI), of which 71% were caused by gram-negative organisms. Of pre-transplant non-LVAD infections, Clostridium difficile infection (CDI) was the most common (26%) followed by urinary tract infection (UTI, 16%) and pneumonia (PNA 15%). Univariate analysis comparing subjects with VSI to those without VSI showed a significant association with time spent outside the hospital prior to transplantation (median 231.8 days vs 142.2 days, P < 0.03) and total time between VAD placement and OHT (244.0 days and 150.5 days, P < 0.002). Logistic regression was performed and significant predictors for VAD-related infection were age and the presence of diabetes, with type of device as an effect modifier. Six months post-OHT survival was not significantly affected by the presence of VSI prior to transplant. There was a trend toward an association between the presence of any infection and post-transplant rejection (P < 0.09). There were 10 post-transplant deaths by 6 months. Of these deaths, 4/10 (40%) were cardiopulmonary and 6/10 (60%) were related to infections.

CONCLUSIONS

Advanced age and presence of diabetes were predictors of VSI, as well as type of VAD device, although device choice is likely affected by many clinical factors including age and comorbidities, as well as institution-specific preferences. VSI was not associated with a decrease in 6-month post-OHT survival. However, infections remain the major causes of death by 6 months post-transplant. Certain infections are associated with an increased risk of rejection, which merits further investigation.

Ventricular Assist Device Infections

This article reviews the diagnostic criteria for ventricular assist device (VAD) infection, pathogenesis, and microbiology as well as the diagnostic pathway when patients present with signs and symptoms concerning for VAD infection. Recommendations regarding infection prevention and management are reviewed as well.

Impact of Change in Body Mass Index on Outcomes After Left Ventricular Assist Device Implantation in Obese Patients

Obesity could be a risk factor portending a poor prognosis after left ventricular assist device (LVAD) implantation. We sought to determine the impact of change in body mass index (BMI) on outcomes in obese patients supported by LVAD. Fifty-nine patients, who received LVAD between January 2010 and June 2015, with BMI ≥30 kg/m at the time of LVAD implantation, were retrospectively analyzed. Patients were divided into two groups based upon whether BMI after 6 months of device support decreased when compared with before. Thirty-eight patients who experienced decrease in BMI (group D) were compared with 21 patients whose BMI increased (group I). Baseline characteristics were similar between the groups except for body weight and BMI, which were significantly higher in group D (BMI: 35.9 ± 4.0 kg/m vs. 33.4 ± 3.5 kg/m; p = 0.018). During mean follow-up of 560 ± 178 days, group I had significantly higher incidence of infection [events per patient-years (eppy): nondevice related: 0.18 vs. 0.35, p = 0.01; device related: 0.1 vs. 0.32, p < 0.01; sepsis: 0.1 vs. 0.32, p < 0.01], heart failure (eppy: 0.1 vs. 0.25, p < 0.01), and renal failure (eppy: 0.03 vs. 0.14, p < 0.01). Survival at 2 years was significantly lower in group I (84.8% vs. 57.1%, p = 0.025). Increase in BMI in obese patients on LVAD is associated with worse survival with a higher incidence of infection, heart failure, and renal failure. Weight control may be a modifiable factor to improve prognosis.

Impact of body mass index on adverse events after implantation of left ventricular assist devices: An IMACS registry analysis

BACKGROUND

Limited data exist describing impact of body mass index (BMI) on post‒left ventricular assist device (post-LVAD) outcomes. We sought to define the relationship between body mass index (BMI) and adverse events (AEs) after LVAD implantation by examining the ISHLT Mechanically Assisted Circulatory Support (IMACS) registry.

METHODS

Patients implanted with a contemporary continuous flow (CF)-LVAD were stratified into 4 groups using pre-operative BMI: underweight (UW; BMI ≤18.5 kg/m²); non-obese (NO; BMI >18.5 to <30 kg/m²); obese (OB; BMI ≥30 to <40 kg/m²); and morbidly obese (MO; BMI ≥40 kg/m²). Freedom from AEs was evaluated using the Kaplan-Meier method and risk factors for development of first AE were identified using multiphase parametric hazard modeling. AEs included infection, thromboembolic events, bleeding, device malfunction, and neurologic dysfunction.

RESULTS

Between 2013 and 2015, a total of 9,408 patients underwent implantation of a CF-LVAD, which consisted of 368 (4%) UW, 5,719 (61%) NO, 2,770 (29%) OB, and 444 (5%) MO patients. Survival among the 4 BMI cohorts was similar at 2years (70.8% to 75.8%, p = 0.24). MO patients were less likely to be free from a non‒VAD-related infection (p < 0.0001) or device-related infection (p = 0.0014) at 2years (50.3%, 70.7%) when compared with OB (58.3%, 78.7%), NO (65.2%, 81.4%), and UW (68.9%, 77.4%) patients. UW (81.5%) and NO (81.3%) patients were more likely to be free from device malfunction at 2years when compared with OB (78.3%) and MO (72.6%) (p = 0.0006). Thromboembolic events were rare and more common in the UW cohort (p = 0.026).

CONCLUSIONS

Although BMI was not correlated with 2-year mortality, an increased rate of infectious and device-related AEs was noted in OB and MO LVAD patients. In a group with few options for transplant, the event morbidity in obese patients can be expected to impact morbidity with longer support durations.

Novel driveline route for prevention from driveline infection: Triple tunnel method

BACKGROUND

The most prevalent and serious infection related to left ventricular assist devices (LVADs) is driveline infection (DLI). From 2014, we employed a revised surgical technique (triple tunnel method), which deployed a longer subfascial driveline (DL) route.

METHODS AND PATIENTS

We retrospectively analyzed 34 patients fitted with either of the two types of axial pumps: HeartMate II (n=23) and Jarvik 2000 (n=11). Prior to 2014, the DL proceeded from the pump pocket just above the posterior sheath of the rectus muscle toward a vertical skin incision at the right lateral border of the rectus muscle. Then, DL was turned leftward into the subcutaneous tissue to redirect its exit to the left side [subcutaneous tissue group (Group S): n=14]. From 2014, we made an additional skin incision below the umbilicus with the aim of lengthening the subfascial DL route [muscle group (Group M): n=20].

RESULTS

DLI occurred in 10 patients (71.4%) in Group S and in 1 patient (5%) in Group M (p<0.05, Chi-square test). The freedom rate from re-admission at 1 year due to DLI was 64% in Group S and 95% in Group M, respectively (p=0.021, log-rank test). Furthermore, logistic regression analysis revealed that DL route was significantly associated with DLI (odds ratio, 10.1; 95% confidence interval, 1.15-275.3).

CONCLUSION

Although a longer follow-up period will be needed, the triple tunnel method may be beneficial in the prevention of DLI.

Bloodstream infections in mechanical circulatory support device recipients in the International Society of Heart and Lung Transplantation Mechanically Assisted Circulation Support Registry: Epidemiology, risk factors, and mortality

BACKGROUND

We used multicenter international data from the International Society of Heart and Lung Transplantation Mechanically Assisted Circulation Support (IMACS) registry to determine bloodstream infection (BSI) event rate, independent risk factors, and association with mortality.

METHODS

Included were patients registered in IMACS from January 2013 through December 2015, assessed BSI event rate of mechanical circulatory support (MCS) and non-MCS-related BSIs, and conducted univariate and multivariate analyses between BSI with baseline characteristics and mortality.

RESULTS

We documented 1,606 BSIs in 1,231 of 10,171 MCS recipients (12%), with an event rate of 2.43 BSIs/100 patient-months within 3 months after implant (early onset) and 1.03 BSIs/100 patient-months after 3 months (late onset). Of these episodes, 1,378 (85.8%) were non- MCS-related BSI. Increasing body mass index and bilirubin were independent correlates of MCS-related BSI. Independent correlates of non-MCS-related BSI included older age, higher body mass index, previous cardiac surgery, baseline chronic renal disease and dialysis, pre-implant frailty, presence of biventricular assist device, total artificial heart or right ventricular assist device, and Interagency Registry for Mechanically Assisted Circulatory Support category 1. Survival after 3 months after implant of patients who developed early-onset BSI was 56.9% at 24 months vs 77.4% in patients without early-onset BSI (p < 0.001). Early-onset BSI was an independent correlate of mortality at 3 months after implantation (hazard ratio, 2.56; 95% confidence interval, 2.09-3.15; p < 0.001).

CONCLUSIONS

Early-onset BSI was associated with significantly increased 24-month mortality. More than 85% of these BSIs were not device related. There is an opportunity for infection prevention practices to decrease the BSI event rate, which may affect 24-month survival. These data can also serve as benchmarking for individual institutions.

Elevated Body Mass Index Is Not a Risk Factor for Adverse Outcomes Following Ventricular Assist Device Implantation

BACKGROUND

Despite ventricular assist devices (VADs) becoming more common in heart failure (HF) treatment, it is still uncertain which patients are more prone to complications. One potential risk factor is increased body mass index (BMI), which is known to increase both all-cause mortality and mortality from ischemic heart disease; however, the role of the BMI in predicting morbidity and mortality following device implantation is unclear.

METHODS

The study population for this single-institution retrospective chart review consisted of 136 patients with HF, who underwent VAD implantation between 2004 and 2015. Patients were divided into 2 groups based on their BMI: a nonobese group (18.5 < BMI < 30.0; n = 82) or an obese group (BMI >30.0; n = 54). These groups were compared at baseline and after implantation for survival, hospital readmission, and adverse events.

RESULTS

No significant difference was found in initial hospital length of stay, number or length of readmissions, or readmission diagnosis. At 1 year, rates of ongoing device support, orthotopic heart transplant (OHT), and death were not significantly different between groups ( P = .89, P = .90, and P = .70, respectively). Multivariate analysis did not identify obesity as an independent predictor of mortality ( P = .90); only biventricular assist device implantation was associated with decreased survival (hazard ratio [HR] = 5.90, P = .002).

CONCLUSION

Obesity in itself should not preclude the use of VAD support in patients with HF, as carefully selected obese patients were shown to have similar rates of hospital readmission, 1-year outcomes, and survival following device implantation compared to nonobese patients.

Effect of obesity on outcomes in patients undergoing implantation of continuous-flow left ventricular assist devices

The purpose of this study was to analyze the effect of obesity on outcomes after continuous-flow left ventricular assist device (CF-LVAD) implantation. A single-center retrospective analysis was performed on 526 chronic heart failure patients who were implanted with the HeartMate II CF-LVAD (n = 403) or HeartWare HVAD (n = 123) between November 2003 and March 2016. Patients were stratified into 4 groups based on BMI: underweight (< 18.5 kg/m², n = 18, 3.4%), normal-weight (18.5-25 kg/m², n = 173, 32.9%), overweight (25-30 kg/m², n = 182, 30.2%), and obese (> 30 kg/m², n = 153, 33.5%). The underweight group was excluded because of its small sample size. Records were reviewed to determine the incidence of postoperative complications and survival. Survival at 1, 6, 12, and 24 months were similar among normal-weight (91.3, 84.4, 76.3, and 67.6%), overweight (90.4, 80.8, 76.5, and 69.6%), and obese patients (90.7, 74.7, 65.3, and 61.3%, p = 0.24). Additionally, obesity was not a significant predictor of mortality in Cox proportional hazard models (hazard ratio 0.98, 95% confidence interval 0.766-1.277, p = 0.13). These findings suggest that appropriately selected obese patients receive similar survival benefit from CF-LVADs compared to non-obese patients, and obesity should not serve as a contraindication to CF-LVAD implantation.

Impact of Chlorhexidine Gluconate Intolerance on Driveline Infection during Chronic Heartmate II Left Ventricular Assist Device Support

Purpose

Driveline exit site (DLES) management following left ventricular assist device implantation is important for preventing driveline infection (DLI). While chlorhexidine gluconate (CHG) is generally recommended for DLES antisepsis, CHG intolerance can develop, resulting in a need for alternative antiseptics. We reviewed our institutional experience with DLES antisepsis methods in HeartMate II patients, comparing outcomes of patients with and without CHG intolerance.

Methods

Between October 2011 and March 2016, 44 patients underwent primary HeartMate II implantation. CHG was used for DLES antisepsis and povidone-iodine (PVP-I) was used in patients with CHG intolerance. DLI was defined by Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) criteria.

Results

Of 44 patients, 37 (84%) received CHG and 7 (16%) received PVP-I antisepsis due to CHG intolerance. Five patients (11.4%) developed a DLI, with an event per patient-year rate of 0.07. Median length of support was 521 days (interquartile range 202–881 days). Characteristics were similar between patients with and without DLI. However, a larger proportion of patients with DLI had CHG intolerance compared to patients without DLI (60.0% vs. 10.3%, p<0.05). Causative organisms were Staphylococcus aureus in CHG-intolerant patients and Stenotrophomonas and Acinetobacter in CHG-tolerant patients. Kaplan-Meier method and log-rank test demonstrated decreased infection-free days in patients using PVP-I rather than CHG (p<0.01).

Conclusions

While the etiology of DLI is multifactorial, CHG intolerance appears to be a risk factor. Our findings highlight the need for larger studies comparing the efficacy of antiseptics for DLES care, particularly for patients with CHG contraindications.

Higher Body Mass Index Increases Risk of HeartMate II Pump Thrombosis But Does Not Adversely Affect Long-Term Survival

BACKGROUND

Obesity has been correlated with various adverse events in patients who receive left ventricular assist devices (LVAD). In this study, we sought to further characterize the role of obesity in this patient population.

METHODS AND RESULTS

We performed a retrospective analysis of 164 patients implanted with a HeartMate II from August 2008 to December 2014. Patients were categorized into 2 BMI groups based on WHO guidelines: BMI 18.5-30 kg/m2(n=99) and BMI >30 kg/m2(n=65). Patient demographics, adverse outcome and long-term survival were compared between the 2 groups. For any outcome associated with BMI groups, we performed a Cox regression to identify confounding comorbidities. Preoperative demographics and comorbidities were similar. Patients with BMI >30 were younger (P=0.01) and had a higher incidence of type 2 diabetes (P=0.01). While rate of pump thrombosis was higher among patients with BMI >30 (P=0.02), overall survival at 2 years did not differ. The most common cause of death was hemorrhagic stroke in the obese group. On multivariable cox regression analysis, BMI was an independent risk factor of pump thrombosis.

CONCLUSIONS

Higher BMI does not reduce survival after VAD implantation but it does appear to increase the risk of pump thrombosis. Further studies to characterize the role of BMI in survival and thrombosis rates are warranted.

Correlation between driveline features and driveline infection in left ventricular assist device selection

Although the survival rate for left ventricular assist device (LVAD) therapy has improved, device-related complications are an unpredictable threat to the patient's quality of life. We focused on driveline infection, and aimed to determine whether specific features of drivelines affect the frequency of infection. We enrolled patients who underwent LVAD implantation and were followed-up at our institute between 2007 and 2015. We counted the occurrences of driveline infection requiring any antibiotic therapy over a 2-year study period. Furthermore, we experimentally measured and compared the outer diameters and stiffness of three devices. Of all, 72 patients received an LVAD during the enrollment period. LVADs were HeartMate II (n = 32), EVAHEART (n = 22), and DuraHeart (n = 18). The outer diameters and stiffness were measured in five of each device. HeartMate II group had the highest driveline infection-free rate among all three devices during the study period (p = 0.042). The driveline of the HeartMate II LVAD had a significantly smaller outer diameter and lower stiffness than that of the other two devices (p < 0.05 for both). In conclusion, device-specific driveline features may affect the development of driveline infection during LVAD therapy.

Driveline Infection Risk with Utilization of a Temporary External Anchoring Suture After Implantation of a Left Ventricular Assist Device

Driveline infections (DLI) are a cause of morbidity after continuous-flow left ventricular assist device (CF-LVAD) implantation. Because driveline trauma contributes to DLI, we assessed whether intraoperative placement of a temporary external anchoring suture (EAS) influenced DLI rate. We analyzed 161 consecutive patients with CF-LVAD (HMII 82; HW 79) implantation. Two groups were defined: placement of EAS (n = 85) or No EAS (n = 76). For NO EAS patients, the driveline was permanently anchored internally to the rectus fascia. Cox proportional analysis was performed to assess the effect of EAS on time to first confirmed DLI. Baseline characteristics were comparable between groups (all p = 0.3). Mean follow-up time was 0.93 years. A total of 18 (11.1%) patients developed confirmed culture positive DLI, with "first infection" rate of 0.13 events/year. Mean time to confirmed DLI was 0.69 years. Driveline infection was less likely (hazard ratio [HR] = 0.28, 0.95 confidence interval [CI] = 0.06-1.25, p = 0.056) to occur in NO EAS (2/18) then in EAS (16/18). Confirmed DLI was comparable between device types (p = 0.3). Multivariable regression adjusted for age, BMI, blood product use, device type, and diabetes showed equivocal effect of EAS (HR = 0.33, 0.95 CI = 0.07-1.54, p = 0.12). Patients with a temporary EAS may have an increased risk of confirmed DLI after device implantation.