Case presentation
A 78-year old gentleman with wild type CA was referred for consideration of CABG. During an amyloid clinic walk test he suffered a cardiac arrest secondary to ventricular fibrillation. Spontaneous circulation returned after a single direct current electrical cardioversion. Myocardial ischaemia was thought to be causative and coronary angiography revealed triple-vessel coronary artery disease with left main stem involvement (Fig 1). Cardiac magnetic resonance imaging (Fig 2) was characteristic of CA, with severe biventricular hypertrophy, mildly reduced left ventricular ejection fraction (LVEF) of 58%, and severely reduced longitudinal function of both ventricles. On tissue characterisation transmural late gadolinium enhancement was present with biventricular involvement.
Other medical history included percutaneous intervention (PCI) to the left anterior descending artery (LAD) 2 years previously and paroxysmal atrial fibrillation. The patient’s baseline functional classification was New York Heart Association II.
The case was discussed in the coronary intervention multi-disciplinary team meeting. Input from amyloid specialists suggested that if the patient were not to have coronary artery disease, prognosis for CA would be 60-84 months. Euroscore II suggested a 2.32% mortality risk, but due to the severity of CA this was felt to be a considerable underestimate. Given complex coronary anatomy and left main stem involvement, albeit in the presence of CA, consensus decision was for high risk inpatient CABG. Considering good LVEF of 58% and excellent functional baseline, a balanced mortality risk of 5-8% was quoted.
Surgery took place two weeks later. The heart was extremely hypertrophic and beefy, and cardiac manipulation was impossible. Peri-operative TOE revealed severe biventricular hypertrophy with preserved systolic function. Three bypass grafts were undertaken: saphenous vein conduits to the posterior descending artery and first obtuse marginal, and pedicled left internal mammary artery to the LAD. The patient came off cardiopulmonary bypass easily on low dose milrinone. In view of severe LV hypertrophy, an intra-aortic balloon pump was placed via the right femoral artery.
Over the next 24 hours the patient became increasingly hypotensive and vasoplegic. Worsening metabolic acidosis ensued despite fluid resuscitation and increasing vasopressor and inotropic support with noradrenaline, vasopressin and milrinone. A Swan-Ganz catheter was inserted, and cardiac index calculated at 1.8L/min/m2 with low systemic vascular resistance. TOE showed a small pericardial collection. Given continued deterioration, the patient returned to theatre for re-sternotomy to exclude tamponade. All conduits were patent, and whilst some clot was evacuated from the pericardium there was no consequent change in haemodynamics. The chest was closed, and the patient returned to ICU with an adrenaline infusion added.
Over the following days the clinical condition slowly improved. Inotropic and vasopressor requirements decreased, and the balloon pump was removed 3 days postoperatively allowing tracheal extubation. As a result of prolonged LCOS, liver and renal failure ensued. The patient developed marked jaundice and required continuous renal replacement therapy. Haemodynamics continued to stabilise over the subsequent 2 weeks allowing weaning of inotropic support. Despite this, there was no resolution of organ failure and he remained jaundiced and filter dependent. Three weeks following surgery the patient again deteriorated with a profound LCOS, requiring increasing doses of noradrenaline, milrinone and adrenaline. Echocardiogram showed severe biventricular impairment with low stroke volume and high filling pressures, but no evidence of tamponade. In the context of CA and multi-organ failure, consensus opinion was that further intubation, ventilation, and organ support would be futile. Following family discussions, a do not resuscitate order was completed and decision for no further escalation in treatment agreed. The patient died shortly thereafter.