EXPERIMENTAL AND CLINICAL TRANSPLANTATION

We report a case of 15-year-old boy with postlingual bilateral total hearing loss following ototoxic medication during his pediatric intensive care unit stay. The patient received the SynCardia total artificial heart implant (50 mL; SynCardia Systems, Inc., Tucson, AZ, USA) for end-stage biventricular heart failure as a bridge to heart transplant. During his time on the urgent heart transplant wait list, he underwent successful cochlear implantation following optimized coagulation and hemostasis status and appropriate anesthetic preparation. Our case represents the world’s first successful cochlear implant in a pediatric patient who received an artificial heart. Despite complexities in this patient population, elective surgical procedures can be performed safely with acceptable morbidity using a collaborative approach with the heart transplant team, including input from cardiovascular surgery, pediatric cardiology, anesthesiology, consultation-liaison psychiatry, physical therapy and rehabilitation, infectious diseases and clinical microbiology, and intensive care unit staff.

Key words : Hearing loss, Heart transplant, Mechanical circulatory support, Vascular assist device

The total artificial heart (TAH) is a complex form of mechanical circulatory support; this pneumatically driven, pulsatile system is used to bridge patients to heart transplant.¹ In pediatric patients with advanced heart failure, TAH is rarely a therapeutic option. In fact, worldwide, only 2% of patients who have received a TAH were under the age of 18 years.¹ However, the 12-month survival after TAH still remains less than 60%.²

There may be an understandable perception among surgeons that elective surgeries for these high-risk patients are associated with significant morbidity and mortality.³There are also several perioperative challenges for anesthesiologists. Common anesthetic concerns include management of anticoagulation, patient monitoring limitations inherent to blood flow characteristics, intraoperative cardiovascular and cerebrovascular events, and postoperative complications.⁴ For this patient group, perioperative planning and a team approach have resulted in these concerns being reduced over time. Recently, there has been a growing number of noncardiac surgery procedures reported in the literature.^5,6 Additional problems may arise during the treatment and intensive care process before and after TAH surgery, which may require an additional intervention as a result of the disease of the patient and the intensive care process itself. Hearing loss can also occur in patients who have received intensive care; however, this situation is not frequent. Mechanical or accidental trauma, administration of ototoxic medications, local or systemic infections, vascular and hematologic disorders, autoimmune diseases, and environmental noise are among the reasons for hearing loss in patients who are receiving intensive care.⁷

We present a 15-year-old male patient with cochlear implantation due to postlingual bilateral total hearing loss. Hearing loss had been caused by the use of amikacin, which is an ototoxic drug used against infections that occur in the intensive care period. This is the first reported case of a cochlear implantation in a patient with TAH.

A 15-year-old male patient (height = 161 cm; weight = 66 kg; body surface area = 1.70, blood group = B positive) with dilated cardiomyopathy was referred to Ankara University with loss of consciousness and cardiogenic shock in July 2016. Venoarterial extracorporeal membrane oxygenation support was conducted about 1 week later. His left ventricular ejection fraction was 22%. Eight days later, the patient received SynCardia total artificial heart implant (50 mL; SynCardia Systems, Inc., Tucson, AZ, USA). On postoperative day 131 after TAH surgery, the patient complained of bilateral hearing loss and was referred to the ear, nose, and throat department.

Previous medical history revealed no evidence of hearing loss, family history of deafness, or any additional anomaly in his childhood. His medical records revealed no evidence of meningitis. However, he had received amikacin (15 mg/kg), an ototoxic antibiotic, against major gram-negative pathogens during his intensive care unit stay. The patient was listed on the high urgent heart transplant wait list and was mobile on the portable Freedom Driver (SynCardia).

The patient’s otoscopic examination was unremarkable. Pure tone audiometry and auditory brainstem response revealed bilateral profound hearing loss. Tympanometry revealed normal type A tympanograms bilaterally. Both computed tomography and magnetic resonance imaging confirmed normal morphology of the labyrinth and intact cochlear nerves.

He was reviewed by a multidisciplinary team (cardiovascular surgery, pediatric intensive care, pediatric cardiology, consultation-liaison psychiatry, physical therapy and rehabilitation, infectious diseases and clinical microbiology, anesthesiology, audiology, and otorhinolaryngology) to perform a cochlear implant. After possible options were discussed with both the patient and his parents, it was then decided that he would benefit from a cochlear implantation because of hearing loss and reduction in cognitive function and adaptation needed for heart transplant. After a discussion of his case with the multidisciplinary team, a right-sided cochlear implant (Nucleus CI24RE with Contour Advance Electrode; Cochlear, Macquarie University, Australia) was decided.

The patient was on warfarin (10 mg/day), which was stopped 3 days before the surgery, and heparinization (loading dose of 50 U/kg and maintenance dose of 20 U/kg/h) was commenced when prothrombin time (international normalized ratio [INR]) was under 1.5. Two hours before surgery, heparinization was stopped. In the operating room, a spare device was available for a possible TAH device malfunction. Flow results for the TAH were closely monitored by the anesthesiology team and the perfusionist. Nonpulsatile blood flow unfavorably affects the monitoring of vital signs, and noninvasive blood pressure was not sufficient in our patient. Under local anesthesia, invasive radial arterial catheterization was performed. In addition, the left internal jugular vein catheter was left in place, which allowed monitoring of central venous pressure and use as large fluid replacement when needed. After monitoring was started, propofol 2 mg/kg, rocuronium bromide 1 mg/kg, and fentanyl 1 μg/kg were administered cautiously, and the patient was intubated orally. Sevoflurane 1 to 1.5 minimum alveolar concentration in 40% oxygen was used for maintenance. Inhaled nitric oxide was also ready to use in case of possible pulmonary hypertensive crisis.

On postoperative day 250 after TAH implant, cochlear implant surgery with round window approach was performed without any perioperative complications; the patient had minimal blood loss (only 50 mL). The duration of the operation was 120 minutes. The patient was extubated in the operating room without any circulatory and respiratory problems. Heparinization was commenced at postoperative hour 6. We started warfarin on postoperative day 1, and heparinization was stopped after achieving INR of 2.0. No complications (infections, hematoma) were observed at postoperative follow-up.

The cochlear implant was switched on at week 4 postoperatively. The audiology team reviewed him 4 and 8 weeks later; he showed continuous improvement in his hearing, with normal impedances. His speech perception results were significantly improved at 3 months after cochlear implant (Figure 1).

Since the first human TAH implantation using the Liotta heart in 1969 by Denton Cooley and Domingo Liotta, life expectancy and quality of life of TAH patients have significantly improved. In parallel, the number of elective and urgent surgical interventions in this subset of patients has also increased dramatically.¹ Arnaoutakis and colleagues³ reported that 47 of 173 patients (27%) who had left ventricular assist devices needed noncardiac surgical interventions. Stehlik and colleagues⁵ found that noncardiac surgical interventions were needed in 24% of patients who had vascular assist devices an average of 229 days before heart transplant. Most of these interventions were orthopedic and abdominal surgeries. In our presented case, the patient who had TAH for 250 days needed no urgent surgery because he had no device-related or noncardiac-related conditions; however, elective surgery was planned for hearing loss rehabilitation.

Clinicians should remain aware of the general health condition and perioperative complications of this patient group. Infection, bleeding, thromboembolism, and device malfunction continue to be the most prominent morbidities in patients with TAH.⁸ Stehlik and colleagues⁵ found that bleeding was the most frequent postoperative complication after abdominal surgery. The general life expectancy for these patients was not affected by noncardiac surgeries.

Total artificial hearts pose unique challenges in anticoagulation because these devices are prone to both thrombotic and hemorrhagic problems. Furthermore, hemolysis by 4 mechanical valves within the TAH should be monitored closely. In contrast, inadequate anticoagulation may lead to thrombus formation and places the patient at risk for devastating thromboembolic complications and device failure. Conversely, hemorrhage requiring allogeneic blood transfusion increases the risk of immunologic sensitization and makes finding an appropriately matched donor organ for heart transplant difficult.⁹

The prophylaxis regimen requires individualized combination therapy to achieve an optimal antithrombotic effect. Anticoagulation management during the perioperative period remains controversial for patients who receive vascular assist devices. Although manufacturer guidelines and institutional standards exist for target INR levels postoperatively, no clear guidelines exist for the preoperative and intraoperative periods. An elective surgery was planned for this case, warfarin was stopped, and heparin was started together with INR follow-up. Heparinization was continued at the earliest time after the operation, and warfarin was started with INR follow-up. Anticoagulation management for patients who receive vascular assist devices remains challenging for the perioperative clinician; current management most likely should be determined on a case-by-case basis.

We present the first published case of a cochlear implantation in a patient with TAH. The number of patients supported with TAH is rising rapidly, and they have longer life expectancy with this device. Noncardiac surgery in these patients can present unique challenges. The maintenance of appropriate perioperative coagulation parameters is essential for successful surgical treatment of TAH patients. Despite the complexities shown in this patient population, elective surgical procedures can be performed safely with acceptable morbidity using a collaborative approach, including input from cardiovascular surgery, anesthesiology, and intensive care unit staff.

Volume: 19 Issue: 12 December 2021

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