Tuesday, 5 November 2013

Porcelain, Risk Aversion and Inappropriate Treatment

Cardiac surgery in patients with a porcelain aorta in the era of transcatheter valve implantation
A healthy ascending aorta is necessary for the safe completion of a heart operation.
Manipulation of the aorta with tubes and clamps, is an integral part of any heart operation. In the aortic valve replacement operation, the aorta has to be clamped and incised to allow surgeon to gain access to the valve. If the aorta is diseased in any way, there is a risk of atheromatous debris breaking off and embolizing (flying off) in the circulation to the brain causing a stroke. A porcelain aorta, so called because the aortic wall has been replaced by sheets of calcified, china like material, can be detected before surgery on the angiogram or CT scan. Unfortunately it often remains undetected until surgery. When a cardiac surgeon, having opened the sternum and pericardium, comes across a porcelain aorta,  his own heart sinks! What was to be a straightforward safe procedure becomes in an instant one that could end badly!  In recent years, a catheter based alternative (that does not involve manipulation of the ascending aorta) to the aortic valve replacement has become available. This procedure was originally known as TAVI or Trans Aortic valve Implantation. More recently, American physicians have, for reasons unknown, have confusingly renamed the procedure as TAVR where the R is replacement. This is factually inaccurate as the replacement  implies the old valve is removed. The native diseased valve is removed in the open surgical  procedure (known simply as AVR - aortic valve replacement) . In the percutaneous procedure, the old native valve is retained and squashed to the side by the new prosthesis. In Europe the procedure is still known as TAVI (well until money and drones force the issue !!).
In the UK, TAVI is only commissioned by the National health Service when the surgical option is ruled out as being too  hazardous or as inappropriate by 2 surgeons. As a treatment, surgical AVR is far more effective and likely to be more long lasting than TAVI.  We have 40+ years data on the procedure.Trials have shown surgical AVR to be as safe as TAVI and in many cases the surgical option is probably safer.
This excellent paper (above) from Germany, where ironically 50% of all implanted aortic valves are TAVI devices, demonstrates that there are effective and safe techniques for dealing with calcified aortas.  It is a crying shame therefore to see relatively young patients being denied a good and effective operation because of calcium in the wall of the ascending aorta by surgeons who for want of a better word are being inappropriately  risk averse.