Hardware for the Heart: The Increasing Impact of Pacemakers, ICDs, and LVADs

Infections in the driveline will often present with obvious signs such as purulent drainage, erythema, and tenderness at the exit site, but providers should have a high index of suspicion if there is dehiscence at the exit site or even persistent serous drainage from the site, as these can suggest a driveline infection. Pump pocket infections and device-related endocarditis can present with vague symptoms such as weight loss, malaise, and a low-grade fever.

A thorough evaluation should be undertaken in all LVAD patients with a suspected infection to detect a source, and cultures of blood, urine, and the driveline exit site should be obtained. Imaging techniques frequently used when considering device-related infections include ultrasound of the pump pocket and echocardiography to evaluate for endocarditis. Computed tomography is also used to evaluate for device-related infections.^6,7,9,10 LVADs are not compatible with MRI.¹¹

The majority of device-related infections are caused by bacteria, although fungal and viral species can be the source as well. Common pathogens implicated include S aureus, S epidermidis, enterococci, Pseudomonas aeruginosa, Klebsiella species and Enterobacter species. Empiric antibiotics with both gram-positive and gram-negative coverage should be initiated for suspected infection related to the device. If the infection has spread to the pump pocket or the device, patients may need surgery for drainage and possible removal of the device.^6,7,9,10

Bleeding and Thrombosis

Bleeding complications occur with pulsatile-flow and continuous-flow LVADs at the same rate, and represent one of the most common adverse events seen in LVAD patients. Sites of bleeding include intracranial, nasal cavity, genitourinary tract, and gastrointestinal (GI).¹¹

Interestingly, GI bleeding occurs at a much higher rate in patients with continuous-flow LVADs than in patients with pulsatile-flow devices.^2,5,11,12 Patients with continuous-flow LVADs are anticoagulated with warfarin (to a target INR of between 1.5 and 2.5) and an antiplatelet agent to prevent pump thrombosis as well as other thromboembolic events.¹¹ In addition to the effects of warfarin and aspirin, several other factors contribute to the increased incidence of GI bleeding, including an acquired von Willebrand disease and the development of small bowel angiodysplasias from the alteration in vascular hemodynamics from the continuous flow.^13,14,15

Emergency physicians should have a high index of suspicion for a bleeding event in patients with an LVAD presenting to the ED. The evaluation of GI bleeding in LVAD patients is the same as in patients without LVADs, and management includes resuscitation with fluids, blood transfusion, and careful correction of coagulopathy. Gastrointestinal bleeding in an LVAD patient necessitates a consultation with a gastroenterologist and admission to the hospital.¹¹

Pump thrombosis, though rare, can result in death and must be considered in cases of MAP < 60 mm Hg and/or an increased power requirement accompanied by a decrease in pulsatility index and flow. Markers of hemolysis such as elevated lactate dehydrogenase or hemoglobinuria also suggest pump thrombosis. Interrogation of the LVAD by the perfusionist is imperative when LVAD patients present to the ED. Echocardiography is the modality of choice in evaluating suspected pump thrombosis. Treatment may require replacement of the pump, or in some cases, anticoagulation or thrombolysis.^2,11

Volume Status

Patients with LVADs can present with complaints of weakness and/or dizziness that can be due to dehydration and/or electrolyte deficiencies. Often, these patients will continue to restrict their salt and fluid intake after device implantation. They are frequently on diuretics, which can contribute to these problems. Checking and repleting electrolytes as well as administering a gentle bolus of IV fluids in patients with a MAP < 60 mm Hg will often correct the hypovolemia and electrolyte abnormalities. Evaluation for sepsis, pump thrombosis, and cannula malposition as causes of hypotension should be undertaken in the appropriate circumstances.^2,11 Severe hypovolemia can interfere with effective LVAD function if it leads to the collapse of the left ventricle over the inflow cannula. Bedside ultrasound can be a useful adjunct in the evaluation of cannula position and volume status.² An emergent consult with a cardiovascular surgeon is indicated in the event of pump thrombosis or cannula malposition.

Conclusion

The number of LVADs implanted each year continues to grow, and EPs need to have a basic familiarity with these devices and how to manage typical complaints seen in the ED. Patients and their caregivers have been given extensive education and training on the care and management of their LVAD components and can be a valuable source of information. They should bring the devices with them to the ED, along with the names and phone numbers of all of the members of their VAD treatment team, who should be called shortly after the patient’s arrival, as well as backup charged batteries to power their LVAD.