A multicentre randomised controlled trial of minimally invasive direct coronary bypass grafting versus percutaneous transluminal coronary angioplasty with stenting for proximal stenosis of the left anterior descending coronary artery.

AMIST investigated how best to treat patients who had a single blocked cardiac artery.  This is called the left anterior descending coronary artery (LAD), and it supplies the heart muscle with blood.  This study looked to compare:

  • minimally invasive direct coronary artery bypass grafting (MIDCAB), which is a type of cardiac surgery where the blocked artery is ‘bypassed’ with another piece of artery


  • percutaneous transluminal coronary angioplasty (PTCA), which is a cardiological procedure where a thin wire is inserted into the blocked artery and a small balloon is inflated to remove the blockage. To keep the vessel open a small mesh tube called a stent may be left in the artery.

The study looked at how well both procedures worked, as well as their value for money. The primary outcome measure that is used to compare how well the procedures worked, looked at how long before any symptoms returned or patients experienced other cardiac-related events such as a heart attack.

A total of 12,828 patients had an angiogram at participating centres from November 1999 to December 2001. An angiogram takes picture of the heart blood vessels to find out where they are blocked. 127 patients were consented to take part.

The study found no evidence that MIDCAB was more effective than PTCA. The procedure costs of MIDCAB were observed to be considerably higher than those of PTCA. Given these findings, it is unlikely that MIDCAB is value for money in treating patients with one blocked heart blood vessel.


paper for this study is available