Infectious complications in four long-term recipients of the Jarvik-7 artificial heart.

This article describes the infectious complications that occurred among four of the longest-term recipients of the Jarvik-7 artificial heart. Infection arising from the drive lines, with spread to the mediastinal periprosthetic space, was the major limiting factor in long-term use of the device in these patients. Periprosthetic infections were due to coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas aeruginosa, and other Pseudomonas species. Other infectious complications incurred by some of the patients included pneumonia, empyema, urinary tract infection, and intravascular line sepsis with Candida. Intensive antimicrobial therapy for prolonged periods seemed to suppress but not to eradicate infection and was accompanied by the appearance of multiresistant bacterial strains. Complications of antimicrobial therapy included diarrhea secondary to overgrowth with Clostridium difficile in two patients. Use of the current device for more than 30 days should be considered extraordinary and should be reserved for patients for whom no other form of life support is available.

Biomaterial-centered sepsis and the total artificial heart. Microbial adhesion vs tissue integration.

The principal barrier to the extended use of the total artificial heart is infection that is centered on the biomaterial constituting the prosthetic device and exacerbated by the surrounding damaged tissue. Ultrastructural studies of total artificial hearts removed from two patients indicate a failure of true tissue integration and diffuse, adhesive bacterial colonization of biomaterial surfaces. Biomaterials are, in part, susceptible to infection because, at the present state of the art, they are usually not well integrated with host tissue or, if hemodynamic, not optimally biocompatible or antiadhesive.

Postmortem microbiological findings of two total artificial heart recipients.

This report describes the postmortem microbiological findings and related gross pathology from two patients who had the longest survival after implantation of the Jarvik-7-100 total artificial heart. We documented extensive polymicrobial colonization at the site of the device and adjacent structures; however, the internal drive lines were remarkably free of bacterial colonization despite evidence of infection at the skin junction and in close proximity to the artificial heart. The polyurethane polymer (Biomer) on the external surface of the device was discolored and pitted in appearance and the Velcro material that attaches the two ventricles together was eroded. A nonspecific mass of tissue that was adherent to the device and to portions of the drive lines contained inflammatory cells, fibrinous debris, and colonies of microorganisms.

Thromboembolic and infectious complications of total artificial heart implantation.

Thromboembolic and infectious events were found to be major complications of long-term total artificial heart implantation in two patients. Similar complications have been reported in other patients, as well as in animal studies. The thromboembolic events and the infectious complications appear to be interrelated. On the one hand, thrombi located on the valves and at the vascular anastomoses of the artificial heart were found to be infected at autopsy; such infections are known to exacerbate formation of thromboemboli. On the other hand, the generation of microthrombi may have contributed to the RES blockade seen in our patients. We hypothesize that this RES blockade led to a progressive decrease in lymphoid system function and impaired the patients' capacity to clear microorganisms from the circulation. These phenomena arose, in part, from the design of the artificial heart and were exacerbated by associated therapy, such as blood transfusions. Our data suggest several measures that might be taken in order to reduce the severity of both the thrombogenic and infectious complications. Improved anticoagulation regimens, which increase the ability of the physician to maintain the proper balance between thrombotic and hemorrhagic potential, are needed. This may require not only improved methods of monitoring anticoagulation and predicting changes in the effectiveness of various agents as other events supervene, but also new anticoagulant and antithrombotic drugs, for example, low molecular weight heparins and prostacyclin derivatives. It is also clear that the design of the artificial heart should be modified in order to improve fluid dynamics so that they will approximate as closely as possible those of the natural heart. This includes redesigning the mounting of the valves to eliminate crevices and discontinuities that allow stagnant flow and predispose to thrombus formation as well as imposing a dP/dt that minimizes shear-related hemolysis, thereby minimizing the need for blood transfusions. Prevention of infections presents a more difficult problem. Transcutaneous lines (regardless of their use) are an obvious route for infection, and attention should be given to minimizing the number and length of use of monitoring lines. However, until a totally implantable drive system is available, the drive lines will remain a potential avenue for the introduction of infections. The risk may be minimized by rigorous attention to care of the exit sites and by improved designs that will provide a better mechanical barrier by, for example, enhancing epithelial ingrowth into the materials of the drive line.(ABSTRACT TRUNCATED AT 250 WORDS)