Data for this review were identified by searches of PubMed, Medline, and references from relevant articles; numerous articles were identified through searches of the extensive files of the authors. Search terms included “ventricular assist device”, “heart-assist devices”, “VAD”, and “LVAD”. They were cross-referenced with search terms including “infection”, “staphylococcus”, “Gram-positive”, “Gram-negative”, fungi”, and “cost(s)”. Several studies presented overlapping data sets, including
ReviewVentricular assist device-related infections
Section snippets
Heart failure
Heart failure occurs in 6–10% of individuals over the age of 65 years in developed nations,1 and over 2 million patients worldwide have end-stage disease.2 The prevalence of heart failure in Europe is 0·3–2%,3 and it affects approximately 10 million people living in nations represented by the European Society of Cardiology.4 According to the most recent American Heart Association statistics, 5 million Americans have congestive heart failure, with 550 000 new cases annually. In 2003, there were
Ventricular assist devices
Ventricular assist devices were developed to improve circulation in patients with advanced congestive heart failure. These devices function as mechanical pumps for damaged ventricles to maintain adequate blood flow. They may also lead to an improvement in myocardial contractility6, 7 and reverse remodelling, as evidenced by reduction of fibrosis and hypertrophy,8 and reversal of chamber enlargement while on ventricular support.9 There are three indications for mechanical assistance: bridge to
Ventricular assist device-related infections and their complications
Ventricular assist device-related infections occur in 18–59% of patients after ventricular assist device implantation.17, 18, 19, 20, 21, 22, 23 In a literature review by Baddour and colleagues,29 infections have been reported to occur in 13–80% of cases. The true incidence of ventricular assist device-related infections is difficult to ascertain for several reasons, including lack of a universal definition of device-related infection, use of historical data, different interpretations of
Pathogenesis
To date, there has been limited investigation of the pathogenesis of ventricular assist device-related infections. This complex process likely involves a combination of ventricular assist device-related, surgical, host, and bacterial factors.
Most ventricular assist devices are large devices and are susceptible to infections at numerous sites, including the internal components of the device (eg, pump membrane and inflow and outflow tracts), the pump pocket, and the driveline exit site. These
Diagnosis and presentation
Although infection is a common complication of ventricular assist device use, there are few documented, prospective, detailed comparisons of clinical signs and symptoms between infected and non-infected individuals. Ventricular assist device-related infections may be associated with few signs and symptoms or may be difficult or impossible to differentiate from infections at other sites. Positive cultures, representing contamination or colonisation, may be incorrectly interpreted as representing
Treatment
Empiric treatment of ventricular assist device-related infections is dependent on the suspected site(s) of infection and the degree of illness. Often, empiric therapy is instituted early because of patients' multiple medical problems. While blood cultures and a full diagnostic work-up are pending (when possible, cultures should be obtained before initiation of antibiotics), empiric treatment of sepsis includes broad-spectrum antibiotics, including Gram-positive (eg, vancomycin for possible
Prevention
Numerous strategies have been used to prevent ventricular assist device-related infections. Without any clinical trial data, the efficacy of these strategies is difficult to gauge based on clinical experience alone.68
Future studies
In the future, a set of criteria to diagnose ventricular assist device-related infections should be generated and validated. Universal criteria will help determine the incidence of ventricular assist device-related infections and allow comparisons of infection rates among different centres, device types, surgical techniques, and prevention strategies. New prevention and treatment strategies, such as those discussed above, should be rigorously investigated. Other prevention strategies—eg, an
Search strategy and selection criteria
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