Patient with Eisenmenger’s Syndrome and Severe Progressive Kyphoscoliosis Presents for Posterior Spinal Fusion

A fourteen year old male patient with Eisenmenger’s syndrome (ES) and severe, progressive kyphoscoliosis presented for posterior spinal fusion, T2-L2. A thorough, preoperative evaluation and multidisciplinary conference was completed to discuss patient management and the very high risk nature of this procedure. The patient underwent the procedure, but decompensated with reduction of the spinal curvature, which we believe produced right ventricular compression leading to an irreversible pulmonary, hypertensive crisis. The patient expired later the same day.


Introduction
Children with ES face the need for anesthesia for non-cardiac surgery in increasing numbers. There are some, but not extensive, guidelines, case reports and outcome data [1][2][3]. Most cases discussed are classified as low/ moderate risk, emergent or obstetrical; not high risk elective surgery as will be described below [4][5][6][7][8][9]. This case report presents a case of a multi-level spinal fusion for progressive, severe kyphoscoliosis in the setting of suprasystemic pulmonary arterial pressure due to ES.

Case Report
A fourteen-year-old, 35.5 kg patient with ES presented for surgery for posterior spinal fusion from T2 to L2 due to severe kyphoscoliosis. Past history included d-transposition of the great arteries (d-TGA), conoventricular ventricular septal defect (VSD), ostium secundum atrial septal defect (ASD) and left superior vena cava (SVC). An arterial switch operation (ASO) was performed at age nine; the patient had already developed pulmonary vascular occlusive disease (PVOD) and Eisenmenger physiology due to the open ASD and VSD. After a multidisciplinary meeting, including orthopedic surgery, cardiology, cardiac anesthesia, and cardiac intensive care, to discuss the risks, benefits and peri-operative management, the decision was made to proceed, despite the very high risk of peri-operative morbidity and mortality.
Surface echocardiogram showed moderate residual ASD and VSD with bidirectional flow, no obstruction to flow from the ASO, elevated right ventricular (RV) and pulmonary artery (PA) pressures. There was mildly depressed biventricular function.
Despite improvements in blood pressure, the patient remained profoundly cyanotic with little evidence of pulmonary blood flow (PBF). ETCO 2 remained less than 10 mm Hg. Surgical closure was completed and the patient was transferred to the Cardiac Intensive Care Unit (CICU) in very critical condition. Despite maximal pulmonary vasodilator therapy, the patient expired later that day.

Discussion
Anesthetic goals for patients with ES include the avoidance of triggering pulmonary vasoconstriction and a pulmonary hypertensive crisis. This is done by maintaining systemic vascular resistance (SVR) and reducing pulmonary vascular resistance (PVR) to promote left to right shunt flow. An important part of this strategy is to avoid hypotension while ensuring adequate anesthesia/analgesia. Our case was uneventful using a combination of dexmedetomidine, remifentanil, low dose sevoflurane and prophylactic vasopressin and NO to achieve these goals. The use of a dexmedetomidine/ketamine combination has been previously reported [9].
Things were progressing smoothly until saturations and ETCO 2 started a precipitous downward trend upon reduction of the spinal curvature. These changes progressed rapidly, despite the reversal of the spinal reduction, to what we believe ultimately was an unbreakable pulmonary hypertensive crisis, followed by cardiopulmonary collapse, despite initiation of maximal pulmonary vasodilator therapy and support. In the average scoliotic patient, it is not uncommon to see transient perturbations in pulmonary function when the abnormal curvature is reduced [11]. We postulate reduction of the spinal curvature in this patient triggered an irreversible pulmonary hypertensive crisis ultimately leading to death. We hypothesize his prior median sternotomy resulted in scarring that adhered the right ventricle to the sternum, rendering the cardiac chambers vulnerable to conformational changes with reduction of the spinal curvature. This resulted in a compressed RV with spinal reduction, greatly diminishing pulmonary blood flow and precipitating the hemodynamic decline. This phenomenon has been reported previously by echocardiography in a patient without structural heart disease, but with pectus excavatum during spinal fusion in the prone position [12]. We also offer as evidence an echocardiogram ( Figure   1) from a different patient with a complete atrioventricular canal (CAVC), and severe scoliosis, undergoing cardiac surgery; this is the pre-repair, post anesthetic induction transesophageal echocardiogram. This picture clearly demonstrates compression of the RV cavity, even in the supine position and without reduction of the spinal curvature.
Spinal fusion has been reported to be one of the orthopedic procedures with the highest incidence of adverse outcomes [13,14]. Combine this with the severe physiological disturbances associated with ES and there is a very high probability of serious morbidity or mortality.We would recommend that patients with ES not undergo elective spinal fusion for severe kyphoscoliosis.