Coronary revascularisation in cardiac amyloidosis

We present a case of coronary artery bypass grafting in a 78‐year‐old man with triple vessel disease and concomitant cardiac amyloidosis. Postoperatively, he developed a profound low cardiac output state and multiorgan failure. He died 3 weeks following surgery. Bypass surgery is rarely performed in patients with cardiac amyloidosis, and there is little in the literature regarding outcomes. The few published cases present a bleak picture, and hence percutaneous coronary intervention should always be preferred.


| INTRODUCTION
We present a case of coronary artery bypass grafting (CABG) in a patient with cardiac amyloidosis (CA) complicated by low cardiac output state (LCOS), multiorgan failure, and death 3 weeks following surgery.

| 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 ischemia was thought to be causative and coronary angiography revealed triple vessel coronary artery disease with left main stem involvement ( Figure 1). Cardiac magnetic resonance imaging ( Figure 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 characterization, 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 multidisciplinary team meeting. Input from amyloid specialists suggested that if the patient were not to have coronary artery disease, prognosis for CA would be 60 to 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, balanced mortality risk of 5% to 8% was quoted.
The surgery took place 2 weeks later. The heart was extremely hypertrophic and beefy, and cardiac manipulation was impossible.   There is a growing body of evidence for the association between aortic stenosis and CA, with this subgroup of patients at increased risk following surgical valve replacement. 4 Although more limited, current evidence of mitral valve surgery in patients with concomitant CA report excellent outcomes. 5 Data on bypass surgery are far more limited but given reasonable reported outcomes in other cardiac surgical procedures, our initial view was that surgery, whilst high risk, was a reasonable approach. Subsequently, we are aware of only four published case reports (comprising five patients) of CABG in patients with CA. Four patients died shortly after surgery due to profound LCOS [6][7][8] ; and one survived the initial postoperative period only to succumb to electromechanical dissociation a few months later. 9 Given our experience and the evidence available, we now conclude that PCI must be preferred to CABG, even when coronary anatomy would normally suggest surgery the intervention of choice.

| SUMMARY
Cardiac amyloidosis is a rare disease associated with poor prognosis.
Although there is some evidence that cardiac surgery can be offered to select patients with concomitant valve disease, outcomes following surgical revascularization are universally poor. Even in highly selected patients, surgical intervention is difficult to justify, and percutaneous options must be preferred.