Abstract
Background and introduction
Troponin-positive chest pain with unobstructed coronary arteries is a distinct entity with different pathophysiological causes. We have previously reported on the incremental diagnostic capability of cardiovascular magnetic resonance (CMR) in this cohort. However, there is paucity of literature on the long-term clinical outcomes of these patients assessed with CMR.
Objectives
Using the unique cohort of patients previously studied, we sought to assess the long-term clinical outcomes in patients with troponin-positive chest pain and unobstructed coronary arteries, as graded by their acute CMR presentation.
Methods
A total of 122 consecutive patients with troponin-positive chest pain and unobstructed coronary arteries undergoing CMR assessment during the acute admission (2010–2014) were studied. The primary endpoint was major adverse cardiac event (MACE), defined as a composite of all-cause mortality and cardiovascular readmissions (heart failure, acute myocardial infarction [AMI], atrial or ventricular arrhythmia and stroke). Patients were grouped into 4 categories based on their initial CMR findings: AMI, acute myocarditis, Takotsubo cardiomyopathy and normal CMR.
Results
The mean age of the study cohort was 55.6±16.5 years and 56.5% were women. CMR (performed at a median of 6 days from presentation) provided a diagnosis in 87% of the patients (38% myocarditis, 28% Takotsubo cardiomyopathy and 21% AMI). Patients with a diagnosis of AMI were prescribed guideline recommended medical therapy. Over a median follow-up of 2524 days (6.9 years), 32 (26.2%) patients experienced a MACE. The all-cause mortality was 2.5%. The most common indication for cardiovascular readmissions in this cohort was heart failure (12.3%) and AMI (9%). In multivariate analysis, a CMR diagnosis of AMI (hazard ratio = 2.6; 95% confidence interval = 1.2, 5.7; p=0.019) and peak troponin (hazard ratio = 1.0003; 95% confidence interval = 1.00003, 1.0006; p=0.028) were significantly associated with MACE after adjusting for age and gender. In addition, CMR diagnosis of AMI was significantly associated with a lower event-free survival rate compared with a diagnosis of non-AMI (adjusted hazard ratio = 2.57, p=0.019) (Figure).
Conclusions
The long-term prognosis of patients with troponin-positive chest pain and unobstructed coronary arteries is not benign. CMR diagnosis of AMI is a significant predictor of MACE even in the absence of significant coronary artery obstruction and despite guideline recommended post AMI therapy.
Figure 1
Funding Acknowledgement
Type of funding source: None
374 Long-term Clinical Outcomes of Troponin-positive Chest Pain and Unobstructed Coronary Arteries Assessed by Cardiovascular Magnetic Resonance Imaging
