Thrombus in normal coronary arteries: retrospective study and review of case reports

Myocardial infarction is rarely caused by non-occlusive thrombus in angiographically normal coronary arteries. The cases reported in the literature are scarce and follow-up was usually short. The efficacy and tolerability of the exclusively medical treatment strategy used in most cases remain unknown.

To evaluate efficacy of medical treatment and long-term prognosis in these patients.

We retrospectively selected and analysed patients hospitalized in our centre between 1998 and 2008 for myocardial infarction caused by non-occlusive thrombus in angiographically normal coronary arteries (defined as stenosis<30%), who were exclusively medically treated. A long-term follow-up was performed. A review of the literature regarding such cases was carried out.

Sixteen patients were identified; apart from smoking, they had few conventional cardiovascular risk factors. Two patients died in hospital. The 14 survivors were followed up for an average of 4.9 years and only one death (non-cardiac cause) and one stroke (related to supraventricular arrhythmia) occurred in this period. Medical treatment included the use of glycoprotein IIb/IIIa inhibitors in 75% of cases. The literature review revealed 36 similar cases due to multiple aetiologies-particularly coronary artery spasm and prothrombotic coagulopathies.

Patients with myocardial infarction secondary to non-occlusive thrombus in angiographically normal coronary arteries seem to have a good long-term prognosis after the acute phase when treated with an exclusively medical strategy. However, initial clinical presentation was often severe, leading to early in-hospital death.