Catecholamine-Induced Cardiomyopathy Secondary to Pheochromocytoma Rescued With Percutaneous Left Ventricular Assist Device: Novel Application of the Impella CP in a Pediatric Patient

CASE REPORT

A 16-year-old otherwise healthy female with a medical history significant only for mild intermittent asthma presented to an outside facility after developing sudden chest pain while playing basketball at school. On arrival, she was hypertensive (blood pressure of 210/150 mm Hg) and in sinus tachycardia (heart rate up to 115 beats per minute). Laboratory values were remarkable only for elevated troponin and brain natriuretic peptide, 12.19 ng/mL (reference value, <0.04 ng/mL) and 507 pg/mL (reference value, <100 pg/mL), respectively. Computed tomography angiography was negative for pulmonary embolism.

The patient developed progressive respiratory failure and was transferred to the pediatric intensive care unit (PICU) where she was intubated and placed on mechanical ventilation support. After intubation, she had persistent tachycardia (heart rate up to 190 beats per minute), but her blood pressure was reported to be only mildly elevated at that point (systolic blood pressure of 140 to 150 mm Hg). Echocardiogram demonstrated a left ventricular ejection fraction <20%.

Of note, the patient had had no recent significant respiratory or other viral symptoms, and a viral panel and urine toxicology screen were negative. Her family history was negative for cardiomyopathies, and later genetic testing was also negative. She was started on milrinone at 0.3 μg/kg/min and transferred from Baton Rouge, Louisiana, to the Ochsner Children's Hospital PICU in New Orleans, Louisiana, for evaluation for advanced heart failure therapies.

On arrival in the afternoon at our facility, she continued to be tachycardic (heart rate in the range of 170 to the 180s beats per minute) and hypertensive (systolic blood pressure 130 to 140 mm Hg), so sodium nitroprusside 0.7 μg/kg/min was added for afterload control. Repeat echocardiogram continued to demonstrate severe left ventricular dysfunction with fractional shortening of 7.0% (reference range, 28.9%-42.5%).

The heart failure team, including a congenital cardiac surgeon, cardiologists, and intensivists, discussed options for support and potential etiologies. Given the degree of tachycardia and the patient's hypertension, the possibility of pheochromocytoma was discussed, and confirmatory diagnostics were planned. However, the patient was in cardiogenic shock with acute risk for decompensation. She was an appropriate size for percutaneous ventricular assist device therapy in the form of the Impella CP (Abiomed, Inc). A ventricular assist device was felt to be superior to and lower risk than ECMO given that only left ventricular support was necessary. The patient's right ventricular function was adequate, and oxygenation and lung compliance were adequate with mechanical ventilation. The Impella CP device would offer better unloading of the left ventricle than medical therapy alone. A plan was made to place the device if any evidence of worsening was seen while medical therapy was being optimized. Oliguria developed within a few hours of the patient's arrival, triggering the team to proceed with insertion of the Impella CP that evening.

The patient was taken to the catheterization laboratory with pediatric interventional cardiologists and the congenital cardiac surgeon. Percutaneous femoral arterial access was planned if the femoral vessels were large enough to accommodate the device with low risk of impaired limb perfusion. The team was prepared to sew a vascular graft onto the femoral artery and insert the device through the graft if necessary to prevent limb ischemia. However, the femoral vessels were large enough to accommodate the device without requiring a graft, and a persistent sciatic artery provided additional protection to the distal limb perfusion. The insertion was uncomplicated, and the device provided excellent support to the patient's cardiac output. Urine output improved immediately after initiation of support, the patient was quickly weaned from the milrinone and sodium nitroprusside, and her fractional shortening increased to 20% by postoperative day 1 and to 22% on postoperative day 2. Coronary angiography performed at the time was unremarkable.

Renal ultrasound subsequently identified an adrenal mass, and magnetic resonance imaging confirmed the presence of pheochromocytoma. Alpha blockade was initiated with doxazosin 10 mg daily. Urine catecholamines were normal; however, plasma metanephrines were markedly elevated at 17,906 pg/mL (reference value, <205 pg/mL).

The patient's ventricular recovery was prompt after optimization of medical therapy. Two days after insertion of the Impella CP, a weaning trial of the device demonstrated only mildly reduced left ventricular function with fractional shortening of 22%, so removal was planned. Removal was performed in the catheterization laboratory with a percutaneous closure device and was complicated by femoral artery dissection that was immediately recognized and repaired by vascular surgery with a good result and no complications to the affected extremity.

The patient was extubated the following day after 3 days of mechanical ventilation and was moved from the PICU to the stepdown unit on hospital day 6. She continued to recover well on the floor and was discharged with normal biventricular function after 12 days in the hospital. She was discharged on doxazosin 10 mg daily and atenolol 12.5 mg daily for blood pressure and heart rate control. Adrenalectomy was planned for a few weeks later.

The patient underwent laparoscopic right adrenalectomy 6 weeks later. The case was uncomplicated, and she was discharged on postoperative day 2. Pathology reported a 4.5-cm pheochromocytoma negative for malignancy. The patient continues to do well with normal biventricular function 7 months after discharge.