Fungal Foe and Mechanical Hearts: A Retrospective Case Series on Candida auris Bloodstream Infection With Left Ventricular Assist Devices

No guidelines currently exist for the management of Candida auris bloodstream infection in patients with left ventricular assist devices (LVADs). We aim to share our management experience through this retrospective case series outlining 15 episodes of C auris candidemia identified in 7 patients over 18 months. The initial source of candidemia was central venous catheter in 5 patients, driveline exit site infection in 1 patient, and possible pump infection in 1 patient. All patients were initially treated with micafungin. Despite susceptibility to micafungin, 4 patients experienced recurrent C auris candidemia. All patients died within 1 year of their first episode of C auris candidemia. Source control is challenging in patients with LVADs, and strict infection prevention measures should be practiced. More studies are needed to evaluate the role of newer antifungal agents, use of combination antifungal regimens, and impact on morbidity in patients with LVADs.

Repeat left ventricular-assisted device exchange and upgrade from second- to third-generation devices in a high-volume single center

BACKGROUND

Pump exchange is an established strategy to treat LVAD-related complications such as thrombosis, infection, and driveline failure. Pump upgrades with an exchange to newer generation devices are being performed to the advantage of the patient on long-term support. The safety and efficacy of a repeat LVAD exchange with a concomitant upgrade to a third-generation pump have not been reported.

METHODS

We performed a retrospective analysis of all consecutive patients who underwent a repeat LVAD device exchange and upgrade to HeartMate III (HMIII) at Houston Methodist Hospital between December 2018 and December 2020.

RESULTS

Five patients underwent exchange and upgrade to HMIII within the specified timeframe. Four patients had already had two prior exchanges (all HMII to HMII), and one patient had one prior exchange (HVAD to HVAD). In all cases, implantation was performed as destination therapy. The surgical exchange was performed via redo median sternotomy on full cardiopulmonary bypass. No unplanned redo surgery of the device component was required. In-hospital mortality was 20% in this very high-risk population. At 1-, 3-, and 6-month follow-up, all discharged patients were on HMIII support, with no major LVAD-related adverse events reported.

CONCLUSION

We report the feasibility and safety of a repeat pump exchange with an upgrade to HMIII in a high-volume center. The decision for medical therapy versus surgical exchange has to be tailored to individual cases based on risk factors and clinical stability but in expert hands, even a re-redo surgical approach grants options for good medium-term outcomes.

Clinical Outcomes of Left Ventricular Assist Device Pump Infection

Few studies have focused on the clinical outcomes and risk factors of left ventricular assist device (LVAD) pump infection, and no standard treatment for LVAD pump infection has been established. Therefore, we used a therapeutic flowchart to manage LVAD pump infections. We retrospectively evaluated 220 patients who underwent continuous-flow LVAD implantation between January 2005 and March 2021 at Osaka University, Japan. First, we performed wound debridement, negative-pressure wound therapy, antibiotic treatment, and omental flap transposition. Subsequently, we administered conservative treatment, scheduled implantable LVAD exchange, or emergent removal of the implantable LVAD and exchange for extracorporeal LVAD or percutaneous LVAD (IMPELLA). Pump infections occurred in 32 patients. The survival rates of patients with pump infections during LVAD support were 93%, 74%, and 61% at 180 days, 1 year, and 2 years after LVAD pump infection, respectively. Fifteen patients underwent successful heart transplantation. Bridge-to-bridge surgery, preoperative use of venoarterial extracorporeal membrane oxygenation or percutaneous LVAD, high lactate dehydrogenase levels, and driveline infection were significantly associated with pump infection. Our study reveals that poor preoperative condition and driveline infection were significant risk factors for LVAD pump infection.

Clinical Outcomes in Patients With Bacteremia and Concomitant Left Ventricular Assist Devices and Cardiac Implantable Electronic Devices

Infection remains a common cause of morbidity and mortality in patients with both left ventricular assist devices (LVADs) and cardiac implanted electronic devices (CIEDs) with limited data describing outcomes in patients who have both devices implanted. We performed a single-center, retrospective, observational cohort study of patients with both a transvenous CIED and LVAD who developed bacteremia. Ninety-one patients were evaluated. Eighty-one patients (89.0%) were treated medically and nine patients (9.9%) underwent surgical management. A multivariable logistic regression showed that blood culture positivity for >72 hours was associated with inpatient death, when controlled for age and management strategy (odds ratio [OR] = 3.73 [95% confidence interval {CI} = 1.34-10.4], p = 0.012). In patients who survived the initial hospitalization, the use of long-term suppressive antibiotics was not associated with the composite outcome of death or infection recurrence within 1 year, when controlled for age and management strategy (OR = 2.31 [95% CI = 0.88-2.62], p = 0.09). A Cox proportional hazards model showed that blood culture positivity for >72 hours was associated with a trend toward increased mortality in the first year, when controlled for age, management strategy, and staphylococcal infection (hazard ratio = 1.72 [95% CI = 0.88-3.37], p = 0.11). Surgical management was associated with a trend toward decreased mortality (hazard ratio = 0.23 [95% CI = 0.05-1.00], p = 0.05).

Left Ventricular Assist Devices: A Primer For the General Cardiologist

Durable implantable left ventricular assist devices (LVADs) have been shown to improve survival and quality of life for patients with stage D heart failure. Even though LVADs remain underused overall, the number of patients with heart failure supported with LVADs is steadily increasing. Therefore, general cardiologists will increasingly encounter these patients. In this review, we provide an overview of the field of durable LVADs. We discuss which patients should be referred for consideration of advanced heart failure therapies. We summarize the basic principles of LVAD care, including medical and surgical considerations. We also discuss the common complications associated with LVAD therapy, including bleeding, infections, thrombotic issues, and neurologic events. Our goal is to provide a primer for the general cardiologist in the recognition of patients who could benefit from LVADs and in the principles of managing patients with LVAD. Our hope is to "demystify" LVADs for the general cardiologist.

Infection following CF-LVAD exchange for non-infectious indications: A systematic review and meta-analysis

Introduction:

Patients on continuous flow left ventricular assist devices (CF-LVADs) often require CF-LVAD exchange. The purpose of this study was to investigate the incidence of infection following CF-LVAD exchange performed for non-infectious indications.

Methods:

An electronic literature search was performed to identify all studies of patients undergoing CF-LVAD exchange for pump thrombosis or device malfunction. Of 2,698 articles identified, 6 studies with 81 total patients met the inclusion criteria. Cohort-level data were pooled for meta-analysis.

Results:

Mean patient age was 60 years (95% CI: 41–78), and 74% were male (95% CI: 61–84). Pump thrombosis was the most common indication for exchange in 70% of patients (95% CI: 47–86). Other indications were driveline fracture and electrical malfunction in 21% (95% CI: 5–56) and 12% (95% CI: 4–33) of patients, respectively. Prior to exchange, 95% of patients were on HeartMate II (HM2) LVADs (95% CI: 86–98) and average duration of support for these patients was 27.1 months (95% CI: 9.3–44.8). The majority were placed on a HM2 following exchange (88% (95% CI: 45–98)) versus HM3 (12% (95% CI: 2–55)). Follow-up was an average of 16.4 months (95% CI: 6.8–26.0). Following exchange, 16 of 81 patients developed infection, with pooled mean incidence of 24% (95% CI: 14–38). 30-day mortality was 14% (95% CI: 7–26). Survival at follow-up was 65% (95% CI: 52–76).

Conclusions:

Infection following CF-LVAD exchange can occur at rates higher than those observed with primary implantation; therefore, effective strategies need to implemented early and consistently to help lower infections rates and help improve outcomes following exchange.

Impella 5.0 support as a bridge to the exchange of an infected left ventricular assist device

A pump infection is a fatal complication specific to left ventricular assist devices. Infection recurrence is a major concern when device exchange is indicated for pump infection. In the present case, we used the Impella 5.0 to maintain proper hemodynamics and to treat the infection in the absence of an implantable device. We demonstrate that the Impella 5.0 can serve as an effective bridge for device exchange by controlling infection and minimizing organ dysfunction, despite prolonged management.

Treatment of HeartMate III-LVAD driveline infection by negative pressure wound therapy: Result of our case series

Driveline infection is one of the most frequent complications following left ventricular assist device (LVAD) treatment and there is no consensus for its management. The standard approach to treat foreign-body infection is complete device ablation, which is not always feasible and therefore not an elected method for LVAD driveline infections. Here we share the results from a series of cases successfully treated for driveline infection by negative pressure wound therapy (NPWT) therapy. Between 2016 and 2020, five male patients were hospitalized in our unit with a driveline infection of HeartMate III-LVAD^®. Ultrasonography and/or thoraco-abdominal CT confirmed the diagnosis, infection localization, and abscess formation. Following an antibiotic treatment, an urgent surgical abscess drainage and debridement of the infected tissues were performed. At the end of the procedure, NPWT was applied. NPWT re-dressing and debridement of wound was performed every 3-4 days. The wound was closed surgically after obtaining negative culture results and good healing. The patients were discharged in good condition, without signs of infection. Two patients underwent successful heart transplantation after 1 and 13 months. Other patients did not show any residual or recurrent infection during the follow-up within 25 months. Driveline infection following LVAD implantation is a significant complication and a challenging in terms of management for both; the surgical team and the patient. These results from our case series report a successful and less invasive approach by using NPWT for the treatment of LVAD driveline infections.

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.

Three year follow-up after less-invasive Left Ventricular Assist Device exchange to HeartMate 3

BACKGROUND

Device exchange to a newer generation left ventricular assist device (LVAD) offers the opportunity to benefit from improved adverse events profiles. We present the three year results of a patient cohort undergoing VAD upgrades to a new generation device focusing on outcomes and adverse events.

METHODS

We present the first series of patients who underwent LVAD upgrade to HeartMate 3. All operations were performed less invasively. Follow-up time was three years after LVAD exchange.

RESULTS

Overall four HeartMate II and two HVAD patients underwent LVAD upgrade. In five cases severe infection of the VAD led to device exchange (83%, 5/6). Three year survival after LVAD exchange was 100% (6/6). In the follow-up examinations one patient showed a single syncope and several low flow alarms (1/6). The remaining five patients showed no technical malfunctions of the LVAD or hemodynamic adverse events (5/6). Four out of five patients whose devices had to be changed due to an infection suffered a local re-infection (4/5), which, however, did not require any further surgical intervention. Four patients were successfully transplanted and two patients were still on device support at three years after LVAD exchange.

CONCLUSIONS

Three-year outcomes and adverse events after LVAD exchange to HeartMate 3 show excellent results. The superior hemocompatibility in terms of pump thrombosis makes the HM3 a favored choice in case of LVAD exchange due previous pump thrombosis. However, in cases of exchange due to device infection the risk of reinfection remains high.

Contemporary Management Strategies in VAD Infection

PURPOSE OF REVIEW

The use of durable ventricular assist devices (VAD) to manage end-stage heart failure is increasing, but infection remains a leading cause of morbidity and mortality among patients with VAD. In this review, we synthesize recent data pertaining to the epidemiology, diagnosis, management, and prevention of VAD infections, discuss transplant considerations in patients with VAD infections, and highlight remaining knowledge gaps. We also present a conceptual framework for treating clinicians to approach these infections that draws on the same principles that guide the treatment of analogous infections that occur in patients without VAD.

RECENT FINDINGS

Despite advances in device design, surgical techniques, and preventative interventions, more than a third of VAD recipients still experience infection as an adverse outcome. Positron emission tomography has emerged as a promising modality for identifying and characterizing VAD infections. High-quality data to support many of the routine therapeutic strategies currently used for VAD infections-including suppressive antibiotic therapy, surgical debridement/device exchange, and novel antimicrobials for emerging multidrug-resistant organisms-remain limited. Although pre-transplant VAD infection may impact some early transplant outcomes, transplantation remains a viable option for patients with most types of VAD infection. Standardized definitions of VAD infection applied to large registry datasets have yielded key insights into the epidemiology of infectious complications among VAD recipients, but more prospective studies are needed to evaluate the effectiveness of existing and novel diagnostic and therapeutic strategies.

Continuous-flow left ventricular assist device systems infections: current outcomes and management strategies

Left ventricular assisted devices (LVADs) are increasingly used for management of patients with advanced heart failure. However, infection remains one of the most commonly reported complications. Diagnosis, as well as treatment of LVAD infections is challenging. There are multiple diagnostic modalities that have been used to assist with accurate diagnosis of LVAD infections. Treatment of the infection can be especially challenging in these patients, given the presence of the implantable device that cannot be easily replaced or removed. There are no clinical trials assessing the best approach to diagnosis, treatment or long-term management of LVAD infections. In this article we review the most recent diagnostic modalities and treatment approaches, as well as offer our guidance on diagnosis and treatment of LVAD infections.

Continuous-flow LVAD exchange to a different pump model: Systematic review and meta-analysis of the outcomes

Despite improved outcomes of modern continuous-flow left ventricular assist devices (CF-LVADs), device exchange is still needed for various indications. While the majority of CF-LVADs are exchanged to the same model, exchange to a different pump model is occasionally warranted. In this meta-analysis, we sought to consolidate the existing evidence to better elucidate the indications and outcomes in these cases. A comprehensive systematic search of adult patient cohorts who underwent CF-LVAD exchange to a different CF-LVAD model was performed. Study-level data from 10 studies comprising 98 patients were extracted and pooled for analysis. Mean patient age was 58 (95% CI: 48-65) and 81% were male. Indication for initial CF-LVAD was ischemic cardiomyopathy in 45% (34-57). Initial device was HeartMate II LVAD (HMII) in 93 (94.9%) and HeartWare HVAD (HW) in 5 (5.1%) patients. After mean CF-LVAD support time of 18.8 (15.2-22.4) months, exchange indications included thrombosis in 71% (43-89), infection in 21% (8-47) and device malfunction in 12% (7-21). HMII to HW exchange occurred in 53 (54.1%) patients, HMII to HeartMate III (HM3) in 32 (32.7%), and HM II to either HW or HM3 in 13 (13.2%) patients. Postoperatively, right ventricular assist device was required in 16% (8-32). Overall, 20% (8-40) of patients experienced a stroke, while HW patients had a significantly higher stroke incidence than HM3 patients (HW: 21% (8-47) vs. HM3: 5% (1-24), P < .01). Overall 30-day mortality was 10% (6-17), while HW had a significantly worse 30-day mortality than HM3 (HW: 13% (7-24) vs. HM3: 5% (1-24), P = .03). Following device exchange from a different CF-LVAD model, HM3 is associated with lower stroke and higher survival when compared to HW.

Pharmacotherapy for durable left ventricular assist devices

Left ventricular assist devices (LVADs) have revolutionized the care of patients with advanced heart failure, yet still require concomitant medications in order to achieve the best possible clinical outcomes. Since the outset of routine placement of durable, continuous-flow LVADs, much of the medication management of these patients to date has been based on International Society of Heart and Lung Transplantation (ISHLT) guidance, most recently published in 2013. Since 2013, numerous multidisciplinary pharmacotherapy publications have increased the LVAD community's understanding of best practices with respect to medications. We identified the major domains of LVAD medication management and conducted a comprehensive search of US National Library of Medicine MEDLINE^® database using keywords chosen to identify medication-related publications of significance dated 2013 or later. Trials pertaining to the HeartMate II™ and the HeartMate™ 3 LVADs (Abbott, Chicago, IL) and the HeartWare™ HVAD™ System (Medtronic, Minneapolis, MN) were chosen for inclusion. Highest priority for inclusion was given to prospective, randomized, controlled studies. Absent these, controlled trials (retrospective or prospective observational) were given next-highest consideration, followed by retrospective uncontrolled studies, and finally case series. Reference lists of qualified publications were reviewed to find any other publications of interest that were not discovered on initial search. Case reports were generally excluded, except where the insight gained was deemed to be uniquely pertinent. This document serves to provide a comprehensive review of the current understanding of optimal medication management in patients with durable, continuous-flow LVADs.

Blood stream infection and outcomes in recipients of a left ventricular assist device

OBJECTIVES

METHODS

We retrospectively analysed all adult recipients of a continuous-flow LVAD between 2006 and 2016 at the Division of Cardiac Surgery, Medical University of Vienna (n = 257; devices: Medtronic HeartWare® HVAD®, Abbott HeartMate II®, Abbott HeartMate 3™). The primary outcome was all-cause mortality during follow-up. Secondary outcomes included the risk of stroke and pump thrombus during follow-up as well as the probability of heart transplantation (HTx). Risk factors for the development of ≥1 positive BC were evaluated additionally.

RESULTS

The incidence of ≥1 positive BC during the first year of LVAD support was 32.1% [95% confidence interval (CI) 26.4–37.9]. Multivariable Cox proportional cause-specific hazards regression analysis showed that a positive BC was associated with significantly increased all-cause mortality [hazard ratio (HR) 5.51, 95% CI 3.57–8.51; P &lt; 0.001]. Moreover, a positive BC was associated with a significantly increased risk of stroke (HR 2.41, 95% CI 1.24–4.68; P = 0.010). There was no association with the risk of pump thrombus or the probability of HTx. Independent risk factors for a positive BC included preoperative albumin and extracorporeal membrane oxygenation/intra-aortic balloon pump support.

CONCLUSIONS

Blood stream infection is common and associated with a significantly increased risk of all-cause mortality and stroke at any given time during LVAD support. Effective strategies of prevention and treatment are necessary.

Clinical implications of LDH isoenzymes in hemolysis and continuous-flow left ventricular assist device-induced thrombosis

Pump-induced thrombosis continues to be a major complication of continuous-flow left ventricular assist devices (CF-LVADs), which increases the risks of thromboembolic stroke, peripheral thromboembolism, reduced pump flow, pump failure, cardiogenic shock, and death. This is confounded by the fact that there is currently no direct measure for a proper diagnosis during pump support. Given the severity of this complication and its required treatment, the ability to accurately differentiate CF-LVAD pump thrombosis from other complications is vital. Hemolysis measured by elevated lactate dehydrogenase (LDH) enzyme levels, when there is clinical suspicion of pump-induced thrombosis, is currently accepted as an important metric used by clinicians for diagnosis; however, LDH is a relatively nonspecific finding. LDH exists as five isoenzymes in the body, each with a unique tissue distribution. CF-LVAD pump thrombosis has been associated with elevated serum LDH-1 and LDH-2, as well as decreased LDH-4 and LDH-5. Herein, we review the various isoenzymes of LDH and their utility in differentiating hemolysis seen in CF-LVAD pump thrombosis from other physiologic and pathologic conditions as reported in the literature.

Recurrent pump thrombosis is common after axial continuous-flow left ventricular assist device exchange

In selected patients with left ventricular assist device-associated infection or malfunction, pump exchange may become necessary after conservative treatment options fail and heart transplantation is not readily available. We examined the survival and complication rate in patients (⩾19 years of age) who underwent HeartMate II to HeartMate II exchange at our institution from 1 January 2010 to 28 February 2018. Clinical outcomes were analyzed and compared for patients who underwent exchange for pump thrombosis (14 patients), breach of driveline integrity (5 patients), and device-associated infection (2 patients). There were no differences in 30-day mortality (p = 0.58), need for temporary renal replacement therapy (p = 0.58), right ventricular mechanical support (p = 0.11), and postoperative stroke (p = 0.80) among groups. Survival at 1 year was 90% ± 7% for the whole cohort and 85% ± 10% for those who underwent exchange for pump thrombosis. In patients exchanged for device thrombosis, freedom from re-thrombosis and survival free from pump re-thrombosis at 1 year were 49% ± 16% and 42% ± 15%, respectively. No association of demographic and clinical variables with the risk of recurrent pump thrombosis after the first exchange was identified. Survival after left ventricular assist device exchange compares well with published results after primary left ventricular assist device implantation. However, recurrence of thrombosis was common among patients who required a left ventricular assist device exchange due to pump thrombosis. In this sub-group, consideration should be given to alternative strategies to improve the outcomes.