Tuesday, 28 August 2012

Virtual Fractional Flow reserve could be useful for Heart Surgeons (and Patients).

Fractional flow reserve is a measure of the pressure drop across a narrowing in an artery when that artery is maximally dilated  - i.e. it tell us whether a stenosis in any artery (usual a coronary artery) is significant.
I remember getting quite excited when I first read about this new technique.
Readers may think  - Crikey excited about FFR - what a geek, what a freak!
I will explain - firstly there is a geeky angle to my excitement. In another world I would have been a radiologist - I love images and imaging and the ability to calculate a physiological parameter from an image is actually quite clever - a bit of magic in fact.
The second reason why I thought that this development could be significant is because I felt it was the killer app for CT angiography. It could break the strangle hold of cardiologists and end their often unhelpful gate keeping function in the management of patients with severe coronary disease. This study demonstrates that the technology is not quite there yet. One group of patients who could benefit from this technology are those who are referred for heart valve surgery.  Most of them always have an invasive coronary angiogram and any apparent stenosis in a major epicardial vessel is usually bypassed by the surgeon at the same time that the heart valve is being replaced or repaired. Although I have always followed the crowd and done this, in recent years I have started to wonder whether this is always necessary.  Does it matter whether the patient gets an additional vein graft that may not be necessary? Well it does - many isolated heart valve procedures can now be done through minimally invasive incisions and the addition of a vein bypass graft precludes the use of a small incision and forces the surgeon to use a full blown median sternotomy. If this test confidently informs the surgeon that a narrowing is not significant and does not need to be bypassed, then this technology could become very important in the management of patients with heart valve disease.