Tatsuhiro Shibata

Prevalence, Clinical Features, and Prognosis of Acute Myocardial Infarction Attributable to Coronary Artery Embolism.

Background— Coronary artery embolism (CE) is recognized as an important nonatherosclerotic cause of acute myocardial infarction. Its prevalence, clinical features, and prognosis remain insufficiently characterized. Methods and Results— We screened 1776 consecutive patients who presented with de novo acute myocardial infarction between 2001 and 2013. CE was diagnosed based on criteria encompassing histological, angiographic, and other diagnostic imaging findings. The prevalence, clinical characteristics, treatment strategies, in-hospital outcomes, and long-term risk of CE recurrence or major adverse cardiac and cerebrovascular events (cardiac death, fatal arrhythmia, or recurrent thromboembolism) were evaluated. The prevalence of CE was 2.9% (n=52), including 8 (15%) patients with multivessel CE. Atrial fibrillation was the most common cause (n=38, 73%). Only 39% of patients with CE were treated with vitamin K antagonists, and the median international normalized ratio was 1.42 (range, 0.95–1.80). Eighteen of the 30 CE patients with nonvalvular atrial fibrillation had a CHADS2 score of 0 or 1. When those patients were reevaluated using CHA2DS2-VASc, 61% were reassigned to a higher risk category. During a median follow-up of 49 months, CE and thromboembolism recurred in 5 atrial fibrillation patients. The 5-year rate of major adverse cardiac and cerebrovascular events was 27.1%. In the propensity score–matched cohorts (n=45 each), Kaplan–Meier analysis showed a significantly higher incidence of cardiac death in the CE group than in the non-CE group (hazard ratio, 9.29; 95% confidence interval, 1.13–76.5; P<0.001). Conclusions— Atrial fibrillation is the most frequent cause of CE. Patients with CE represent a high-risk subgroup of patients with acute myocardial infarction and require close follow-up.

Coronary Artery Ectasia Predicts Future Cardiac Events in Patients With Acute Myocardial InfarctionHighlights

Objective— Coronary artery ectasia (CAE) is an infrequently observed vascular phenotype characterized by abnormal vessel dilatation and disturbed coronary flow, which potentially promote thrombogenicity and inflammatory reactions. However, whether or not CAE influences cardiovascular outcomes remains unknown. Approach and Results— We investigated major adverse cardiac events (MACE; defined as cardiac death and nonfatal myocardial infarction [MI]) in 1698 patients with acute MI. The occurrence of MACE was compared in patients with and without CAE. CAE was identified in 3.0% of study subjects. During the 49-month observation period, CAE was associated with 3.25-, 2.71-, and 4.92-fold greater likelihoods of experiencing MACE (95% confidence interval [CI], 1.88–5.66; P<0.001), cardiac death (95% CI, 1.37–5.37; P=0.004), and nonfatal MI (95% CI, 2.20–11.0; P<0.001), respectively. These cardiac risks of CAE were consistently observed in a multivariate Cox proportional hazards model (MACE: hazard ratio, 4.94; 95% CI, 2.36–10.4; P<0.001) and in a propensity score–matched cohort (MACE: hazard ratio, 8.98; 95% CI, 1.14–71.0; P=0.03). Despite having a higher risk of CAE-related cardiac events, patients with CAE receiving anticoagulation therapy who achieved an optimal percent time in target therapeutic range, defined as ≥60%, did not experience the occurrence of MACE (P=0.03 versus patients with percent time in target therapeutic range <60% or without anticoagulation therapy). Conclusions— The presence of CAE predicted future cardiac events in patients with acute MI. Our findings suggest that acute MI patients with CAE are a high-risk subset who might benefit from a pharmacological approach to controlling the coagulation cascade.

Response to Letter Regarding Article, "Prevalence, Clinical Features, and Prognosis of Acute Myocardial Infarction Attributable to Coronary Artery Embolism".

We thank Dr Nadir for his interest in our work.1 Among 52 patients with coronary artery embolism (CE), 38 had atrial fibrillation (AF) and the remaining 14 had no evidence of AF on admission and during hospitalization. During follow-up, 2 of 14 patients (14.2%) developed AF; they had idiopathic dilated cardiomyopathy and postprosthetic aortic valve replacement, respectively. The time from discharge to the diagnosis of AF was 17 months and 18 months, respectively. One reason for this low rate of AF detection during follow-up may be ECG monitoring for at least 10 days (median, 18 days) during hospitalization at our institution. As Dr Nadir noted, a previous study reported a median of 41 days of ECG monitoring to detect AF in cryptogenic stroke patients with insertable cardiac monitors.2 …