π - From the Greeks to the Cardiologists
The π sign- Aberrant OM from LAD
S Salahuddin, S Ramakrishna, S Seth, B Bhargava*
Department of Cardiology, Cardiothoracic Sciences Centre, All India Institute of Medical Sciences, New Delh

Introduction

Pi the 16th letter of the Greek alphabet- a mathematical variable, the value of which was described by the Babylonians, is an entity which has applications to mathematicians and non-mathematicians alike. Pi has caught the imagination of people in nearly all walks of life. So how then can the cardiologists be far behind.

CASE REPORT

We report a 58 year old gentleman with history of chronic stable angina of 6 months duration, who was taken up for PCI of a significant proximal LAD lesion. The angiogram revealed an aberrant OM arising from the LAD, which in the RAO caudal projection,  gives rise to an angiographic appearance mimicking the greek letter π - pi , the so-called “pi sign”.

DISCUSSION

According to literature, coronary anomalies affect less than 1% of the general population1. Traditional taxonomy describes the obtuse marginal arteries to always arise from the left circumflex artery. which cannot categorise arteries not arising from the left circumflex artery and yet supply blood to the obtuse margin of the left ventricle.

The ‘π (Pi) sign’ previously described by Brofferio et al2, has clinical significance.  Patients with such an aberrant origin of an OM branch from the LAD may develop extensive anteroseptal, apical, and posterolateral ischemia from a proximal LAD occlusion. This type of anomaly should also be considered when an OM branch of the left circumflex artery appears to be missing on a coronary angiogram.

References:

1.Normal and anomalous coronary arteries: definitions and classification.
Angelini P - Am Heart J - 01-Feb-1989; 117(2): 418-34

2.Alessandra Brofferio, MD, Jamshid Shirani, MD, and John Chapman, MD. The Pi Sign as an Indicator of Aberrant Origin of Obtuse Marginal Coronary Artery. Am J Cardiol 2007;100:180–181

Correspondence: Dr B Bhargava*,Department of Cardiology, Cardiothoracic Sciences Centre, Executive Director , Stanford India Biodesign Programme,All India Institute of Medical Sciences, New Delhi-110029
Email: BalramBhargava@yahoo.com