Wound complications after left ventricular assist device implantation

Massive intercostal hemorrhage after implantation of an intrapericardial ventricular assist device: A case report

Left ventricular assist devices (LVADs) have become integral to the treatment of advanced heart failure. Surgical bleeding is a known complication of LVAD placement but is most associated with intraperitoneal pump locations. Here we describe a case of massive postoperative hemorrhage secondary to erosion of an intrapericardial LVAD into an intercostal artery with an associated rib fracture.

Impact of adverse events on ventricular assist device outcomes

Left ventricular assist devices have been proven to be superior to medical therapy for advanced heart failure patients awaiting heart transplantation and viable alternatives to transplantation for destination therapy patients. Improvements in the design of ventricular assist devices have been rewarded by a decrease in adverse events and an increase in survival. Despite significant progress, even the latest generation left ventricular assist devices are burdened by a significant long-term adverse events profile that will increasingly challenge physicians as patients survive longer on implantable mechanical circulatory support. In this review, we analyze the impact of long-term adverse events on clinical outcomes in the major trials of continuous flow left ventricular assist devices. We discuss several of the more pertinent and interesting adverse events, examine their potential causes, and explore their future implications.

Left ventricular assist device-related infections: past, present and future

Over the last decade, left ventricular assist device (LVAD) implantation has emerged as an alternative treatment strategy in patients with advanced heart failure irrespective of their transplant eligibility. However, success and applicability of this therapy is largely limited by high complication rates associated with these devices. Although superior outcomes have been achieved with the second-generation continuous-flow LVADs, device-related infections continue to be a prevalent complication in this patient population and contribute significantly to the financial burden of this therapy due to an increased need for hospitalizations and surgical interventions. Patient selection, device design and LVAD-induced immune system dysfunction appear to be major risk factors for the development of device-related infections. Improvements in device design and better patient selection strategies, particularly with respect to identifying individuals with genetic susceptibility to device-related infections, may further reduce this prevalent complication and improve outcomes in patients with advanced heart failure.

Microbiology of infection in mechanical circulatory support

The results of MCSS therapy for patients with severe heart failure are improving, and there are increasing numbers of implants as device therapy enters the era of permanent use (i.e., destination therapy). Device-related infection of implanted pumps and sepsis remain important risk factors for death, and once infections are established on biomaterial surfaces they usually persist despite prolonged antimicrobial therapy. This paper covers the topic of infection in mechanical circulatory support. Methods to prevent and manage infection are described. Recent information from the field of microbiology that is relevant to understanding device-related infection is reviewed, including the mechanisms for microbial adhesion to prosthetic surfaces, quorum sensing, and biofilm formation. Characteristics that are important to antimicrobial resistance of microbes dwelling in biofilms are described (e.g. responses to microenvironmental conditions that result in resistance to antibiotics). This information may lead to new therapies that further diminish rates of device infection, and allow complete eradication of infections when they occur.

Drive-line exit-site infection in a patient with axial-flow pump support: successful management using vacuum-assisted therapy

Infection remains one of the most common causes of mortality during left ventricular assist device (LVAD) support, and poses major challenges to surgeons implanting these devices. We describe the case of a patient supported with an axial-flow pump for dilative cardiomyopathy, who experienced drive-line exit-site infection and was treated with extensive surgical debridement and reconstruction by applying vacuum-assisted therapy. He remained infection-free after wound healing and, after 7 months of mechanical support, had native heart function recovery and underwent LVAD removal.

Clinical Outcomes Are Similar in Pulsatile and Nonpulsatile Left Ventricular Assist Device Recipients

BACKGROUND

Despite concerns about the adequacy of support provided by continuous-flow left ventricular assist devices (LVADs), direct comparisons of patient characteristics and outcomes between first-generation pulsatile and second-generation nonpulsatile LVADs are absent. We hypothesized that a nonpulsatile Jarvik 2000 LVAD (Jarvik Heart, Inc, New York, NY) would result in comparable outcomes to those of similarly ill patients implanted with a pulsatile LVAD (Novacor, WorldHeart Inc, Oakland, CA; and HeartMate XVE, Thoratec, Pleasanton, CA).

METHODS

We retrospectively compared common pre-LVAD clinical characteristics and indicators of heart failure severity between 13 pulsatile and 14 nonpulsatile LVAD recipients. The outcomes analyzed were either heart transplantation, if the LVAD was intended as a bridge to transplantation, or hospital discharge if the intention was destination therapy.

RESULTS

There was no significant difference between groups in pre-LVAD disease severity indicators. Nonpulsatile LVAD recipients had a significantly smaller body surface area (1.9 +/- 0.2 m2 versus 2.1 +/- 0.2 m2, p = 0.04) and cardiopulmonary bypass time was also significantly shorter (61 +/- 34 minutes versus 110 +/- 49 minutes, p = 0.01). Aside from duration of initial intensive care unit stay (nonpulsatile, 10 +/- 16 days; pulsatile, 14 +/- 11 days; p = 0.02), there was no difference in post-LVAD outcomes: 10 of 14 nonpulsatile and 8 of 13 pulsatile LVAD patients achieved the combined end point (p = 0.69).

CONCLUSIONS

Similarly ill congestive heart failure patients benefited equally well from either a nonpulsatile or a pulsatile LVAD. This may support an expanded role for nonpulsatile LVADs in the treatment of severe heart failure.

Successful Salvage of Ventricular-Assist Devices in the Setting of Pump Pocket Infection

Implantable ventricular-assist devices (VADs) have been approved for use both as a bridge to heart transplantation and as a destination therapy. Rising numbers of patients are surviving with these devices for several years. However, infections of these foreign bodies are serious and frequent complications, often requiring removal of the implant, with serious health consequences. Given the increased use of VADs as life-preserving destination therapy, explantation of these devices in the face of infection is impractical. We evaluated and successfully treated 2 patients with VAD pocket infections referred by the cardiac surgery service at our institution using aggressive surgical and pharmacologic therapy, with the goal of preserving the VADs. However, this is still a largely unsolved dilemma requiring further exploration into prevention and treatment since these devastating infections will likely become a more frequent reconstructive challenge.

Omental Transposition Flap for Salvage of Ventricular Assist Devices

BACKGROUND

The use of ventricular assist devices for patients with end-stage cardiac failure awaiting heart transplantation has become increasingly common. Ventricular assist devices improve the longevity and the quality of life for these patients. In addition, they serve as a bridge to cardiac allograft transplantation until a donor heart is found. However, ventricular assist device-related infections remain a major problem complicating their long-term use. Clinical infection and sepsis can critically threaten these patients with ventricular assist devices. Infection can delay immediate transplantation and potentially require the removal of the device for definitive treatment of the problem.

METHODS

Patients who underwent insertion of a ventricular assist device at the University of Pittsburgh Medical Center were identified through accessing the medical records archives of the hospital. Review of patients' medical records was conducted to obtain patient demographics, preoperative diagnosis and disease state, type of ventricular assist device inserted, postoperative day of ventricular assist device infection onset, infectious organism identified, timing of omental flap procedure after the initial insertion, duration of ventricular assist device support before cardiac transplantation, and patient follow-up.

RESULTS

There were 76 patients who underwent a ventricular assist device insertion procedure during the 4-year period between January of 2000 and January of 2004. Of the 76 patients who received a device, 11 (14 percent) had evidence of clinical infection secondary to insertion. Two of these 11 patients died before surgical intervention, four had their devices explanted, and the remaining five underwent omental flap transposition with bilateral pectoralis major advancement flaps in surgically addressing their infections. Of the five patients with infections who received omental transposition flaps, two went on to undergo successful transplantation, two continue to await cardiac allograft transplantation, and one died as a result of an unknown cause.

CONCLUSIONS

The authors present their experience with five patients who received omental transposition flaps to cover infected ventricular assist device pumps and the associated tubing in large, open sternoabdominal wounds. Treatment included the direct application of an omental transposition flap over the infected device with use of a bilateral pectoralis advancement flap to aid in complete sternal and skin closure of the sternal wound defect. In each of these cases, the use of the omental flap was followed by resolution of the mediastinal infection. In addition, the treatment with an omental flap prevented the removal of infected devices in patients who were otherwise pump dependent during their waiting periods for transplantation. The use of omental transposition flaps can be an effective technique in salvaging infected ventricular assist devices and preserving this valuable device for patients awaiting a cardiac transplant.

Ventricular assist device-related infections

Heart failure is a leading cause of death in developed nations despite medical management. Cardiac transplantation is a potentially lifesaving intervention for approximately 4000 advanced heart failure patients per year; however, the demand for donor hearts far exceeds the supply. Ventricular assist devices provide temporary support for patients with severe heart failure until myocardial recovery occurs or a donor heart becomes available. For those ineligible for transplantation, ventricular assist devices may be used permanently and have demonstrated reduced mortality and an improved quality of life compared with continued medical therapy. Nonetheless, these devices are under-used, in part due to the frequency of complications. Device-related infections are one of the most frequent sequelae of ventricular assist device placement and occur in 18-59% of cases. Infections can involve any part of the device and confer substantial morbidity and mortality. Here, we provide an introduction to ventricular assist devices, explore the nature and pathogenesis of ventricular assist device-related infections, discuss problems with diagnosis, and present treatment and prevention strategies.

Multicenter experience: prevention and management of left ventricular assist device infections

Implantable left ventricular assist devices (LVADs) have demonstrated clinical success in both the bridge-to-transplantation and destination-therapy patient populations; however, infection remains one of the most common causes of mortality during mechanical circulatory support. Thus, serious LVAD infections may negate the benefits of LVAD implantation, resulting in decreased quality of life, increased morbidity and mortality, and increased costs associated with implantation. Prevention of device-related infection is crucial to the cost-effective use of mechanical circulatory support devices. Therefore, adherence to evidence-based infection control and prevention guidelines, meticulous surgical technique and optimal postoperative surgical site care form the foundation for LVAD associated infection prevention.

Heart Transplantation in a Patient With a Left Ventricular Assist Device and Methicillin-Resistant Staphylococcus Aureus Infection

We report a patient who underwent implantation of a DeBakey left-ventricular assist device and developed a methicillin-resistant Staphylococcus aureus drive line infection on postoperative day 304. The patient was forwarded to urgent heart transplantation with a successful outcome.

Experimental Testing of a New Left Ventricular Assist Device???The Microdiagonal Blood Pump

All existing ventricular assist devices are associated with a considerable number of serious complications. This article reports on the first animal tests with a newly developed microdiagonal blood pump (MDP). Six adult female sheep weighing 80 to 90 kg underwent implantation of the microdiagonal blood pump. The inflow and outflow conduits were anastomosed to the left atrium and the descending aorta. Pump flow was adjusted to 2-3 L/minute. Hemodynamic and echocardiographic data, as well as blood samples, were measured over the entire test period of 7 days. All internal organs and the pump were explanted for thorough examination at the end of the trial. Mean arterial (range 88.5 +/- 13.1-103.7 +/- 10.7 mm Hg) and mean pulmonary arterial (18.3 +/- 2.7-21.6 +/- 20.5 mm Hg) pressures, as well as the pulmonary capillary wedge pressure (14.2 +/- 3.0 - 16.6 +/- 4.0 mm Hg), remained stable during the whole test period. Cardiac output (4.9 +/- 0.7 --> 3.2 +/- 0.5 L/minute) decreased postoperatively caused by partial unloading of the heart. Left ventricular end diastolic (4.1 +/- 0.5 --> 3.6 +/- 0.3 cm) and end systolic (3.2 +/- 0.4 --> 2.8 +/- 0.5 cm) diameters, as well as the ejection fraction (57 +/- 9 --> 42 +/- 5%), decreased after MDP implantation and did not change during the test period. Mean number of platelets (428 +/- 54 --> 286 +/- 66 x 10(3)/microL) and hemoglobin (9.8 +/- 1.3 --> 6.3 +/- 0.8 g/dL) decreased perioperatively because of surgical reasons and increased continuously in the postoperative course (platelet count and hemoglobin on day 7:441 +/- 74 x 10(3)/microL and 7.2 +/- 1.1 g/dL, respectively). Free hemoglobin was not enhanced in the postoperative course (mean value during the test period: 18.8 mmoL/L). Histologic examination of the organs did not demonstrate any infarctions of internal organs other than typical operative sequelae such as chronic pericarditis and some degree of atelectasis of the left lungs. These results demonstrate that the microdiagonal pump may be a promising alternative to the currently used ventricular assist devices, if long-term trials support these results.

Infection in ventricular assist devices: prevention and treatment

Infection is one of the most important challenges to the use of implanted mechanical circulatory support systems (MCSS), particularly as we enter the era of permanent device use in patients who are not candidates for cardiac transplantation. This paper describes the pathogenesis of MCSS infection, with particular attention to the role of biofilm-forming bacteria. Suggestions are presented for the prevention and treatment of infections in implanted MCSS.

Successful treatment of Novacor pump pocket infection by omental transposition

Device-related infection remains a major factor restricting the long-term use of left ventricular assist systems. Severe pocket infection is especially difficult to manage and removal of the device has been the only curative treatment in most cases. We report a case of a Novacor device pocket infection treated successfully with continuous local irrigation and transposition of omental flap. This procedure provides another option for the management of pocket infection, which is mandatory for destination therapy the permanent usage of LVAS for the purpose of circulatory supports in patients with end-stage heart failure, who are not indicated for heart transplantation.

Successful cardiac transplantation after 4 cases of DeBakey left ventricular assist device failure

Left ventricular assist devices (LVADs) are an established surgical therapy for patients with end-stage heart failure as a bridge to cardiac transplantation. Major disadvantages of these devices are thromboembolic events, bleeding complications, infections, and malfunctions. We report on our experiences with DeBakey LVAD malfunctions requiring LVAD exchange in 4 patients. All patients underwent subsequent cardiac transplantation and are doing well now.

Nosocomial bloodstream infections in patients with implantable left ventricular assist devices

BACKGROUND

Implantable left ventricular assist devices (LVAD) are used as a bridge to transplantation but are associated with a high risk of infection including nosocomial bloodstream infections (BSI).

METHODS

We retrospectively reviewed the medical records of all patients with implantable LVAD at the Cleveland Clinic with 72 hours or longer of LVAD support from January 1992 through June 2000, to determine the attack rate, incidence, and impact of nosocomial BSI in patients with LVAD. A nosocomial BSI was defined using Centers for Disease Control and Prevention definition. An LVAD-related BSI was defined as one where the same pathogen is cultured from the device and the blood with no other obvious source. Two hundred fourteen patients were included in the study (17,831 LVAD-days).

RESULTS

One hundred forty BSI were identified in 104 patients for an attack rate of 49% and incidence of 7.9 BSI per 1000 LVAD-days. Thirty-eight percent of the BSI were LVAD associated. The most common pathogens causing BSI were coagulase-negative staphylococci (n = 33), Staphylococcus aureus, and Candida spp. (19 each), and Pseudomonas aeruginosa (16 each). A Cox proportional hazard model found BSI in patients with LVAD to be significantly associated with death (hazard ratio = 4.02, p < 0.001). Fungemia had the highest hazard ratio (10.9), followed by gram-negative bacteremia (5.1), and gram-positive bacteremia (2.2).

CONCLUSIONS

Patients with implantable LVAD have a high incidence of BSI, which are associated with a significantly increased mortality. Strategies for prevention of infection in LVAD recipients should focus on the drive line exit site until technical advances can achieve a totally implantable device.