169 CARDIAC AMYLOIDOSIS AND CORONARY ARTERY DISEASE: INSIGHTS FROM A RETROSPECTIVE OBSERVATIONAL STUDY
Authors: De Michieli Laura , Sinigiani Giulio , Deola Petra , Mainardi Chiara , Marra Martina Perazzolo , Basso Cristina , Iliceto Sabino , Cipriani Alberto 
Published: December 2022

Abstract

Introduction
Patients with cardiac amyloidosis (CA) frequently present with heart failure with various extra-cardiac red flags. However, some patients can present with typical or atypical chest pain or even mimicking an acute coronary syndrome. Significant epicardial coronary artery disease (CAD) and CA can coexist, but microvascular dysfunction might also play a role. The aims of this study were to systematically investigate clinical indications for invasive coronary angiography (ICA) in patients with CA, to verify the prevalence of significant epicardial CAD and its relation to the symptoms at presentation, and to start investigating the role cardiac troponin (cTn) in this setting of patients with multiple possible causes of myocardial injury.

Methods
Retrospective observational study of patients with CA, both transthyretin (ATTR-CA) and light chain (AL-CA) evaluated in our Cardiac Amyloidosis Outpatient Clinic and undergoing ICA for clinical indication. Significant epicardial CAD was defined as stenosis ≥ 50% of the left main coronary artery and/or ≥ 70% of the other epicardial vessels.

Results
Of the 161 patients initially evaluated, 67 (42%) underwent ICA; after exclusion of those with ICA older than 5 years than CA diagnosis, the final cohort was of 61 patients, 12 (20%) AL-CA and 49 (80%) ATTR-CA. Patients with significant epicardial CAD at the index ICA had ATTR-CA and were more frequently affected by systemic hypertension and dyslipidemia. In 42 (69%) patients ICA was performed during an urgent hospitalization and in 38 (62%) patients CA diagnosis was already established/suspected at the time of the index ICA. The most common indication for ICA was chest pain (n=24, 39%), followed by dyspnea (n=21, 34%); electrocardiographic alterations/arrhythmias were the main indication for 4 patients (6.6%) while imaging for 6 (9.8%). In the remaining 6 patients (9.8%), there were other indications. Prevalence of significant epicardial CAD at the index ICA was 28% (n=17), up to 36% (n=22) if patients with previous coronary revascularization but without actual critical stenoses at index ICA were included. Among those presenting with chest pain (n=24), 9 (38%) had significant epicardial CAD at the index ICA whereas 15 (62%) did not. Considering those presenting with an acute event, the most frequent indication for ICA was chest pain (n=20, 48%); among these patients with chest pain, 55% did not have evidence of significant epicardial CAD whilst 45% did. Regarding cardiac troponin (cTn) values, concentrations at all timepoints were similar between patients with and without significant epicardial CAD at index ICA, also considering those presenting acutely and for chest pain.

Conclusion
In our cohort of CA patients undergoing ICA, the main clinical indication was chest pain; however, the majority of those presenting with chest pain did not have evidence of significant epicardial CAD. Significant epicardial CAD was present in around one third of patient, which is slightly less than what reported in non-amyloidotic HFpEF patients. The role of cTn in this setting is controversial, due to the possible concomitant causes of chronic and acute myocardial injury in these patients.