One in four at risk of little known heart defect
One in four people in the UK has a heart defect known as a patent foramen ovale or PFO. In most people it causes no problems but in some people it can put them at risk of a stroke as I discovered two years ago.
I have to admit I had never heard of this particular heart defect but I am really glad I found out that I had one. Two years ago I was enjoying a well deserved holiday on a Greek island when I had a stroke totally out of the blue. It happened in my sleep so I had no idea until I awoke to find I was paralysed down my left side.
Being treated in a Corfu hospital was a hell of an experience. When we arrived in the lobby it was teeming with all humanity and so noisy we could barely make ourselves heard. Nevertheless I cannot fault the doctors there who followed all the correct procedures and ensured I fully recovered apart from a numb thumb!
On my return to the UK exhaustive tests showed no obvious cause which meant it was branded a ‘cryptogenic stroke’. I was lucky enough to finally be referred to the top stroke physician in the UK, Professor Tony Rudd at St Thomas’ Hospital, London.
He was immediately on the case. He told me my stroke may have been caused by atrial fibrillation-where the heart beats erratically. Stroke is believed to be up to 17 fold higher in those with this condition. I was duly fitted with a 24 hour heart monitor but all was found to be functioning normally.
Next Professor Rudd wanted to see whether I might have this heart defect which is present in one in four of the general population. This was the first time I had ever heard of a patent foramen ovale and I was a bit skeptical that it could have caused my stroke.
All babies in the womb have a small tunnel in the heart wall that divides the two upper chambers known as a foramen ovale. This hole usually closes up soon after the baby is born but sometimes it fails to do so and is then known as a patent foramen ovale or PFO.
Usually it causes no problems but where someone has had a stroke with no known cause, doctors sometimes look for it. Professor Rudd recommended I have a ‘bubble’ test to check.
And so it was I found myself in a room hooked up to a computer and being injected with agitated saline. One doctor pumped the bubbles into my veins whilst the other watched on the screen to see if the bubbles crossed through this possible hole in my heart.
It was clear from both their faces I was a textbook case-hundreds of bubbles were crossing freely through the hole. The theory is that I may have had a tiny clot from the plane journey which would normally have dissolved in the lungs, but because of the hole travelled to my brain.
So what next? I was told there was a procedure known as percutaneous PFO closure which would close the hole in my heart permanently. Although there is no evidence to show it would prevent another stroke it seemed likely that had it caused my first one it would at least be preventative.
I was frankly terrified of having the op but logic told me that the hole was not meant to be there and had already caused me problems so why not close it? I agreed to have the op and was booked in for the day after my birthday.
I was taken down into the bowels of the hospital where the cath lab is situated. This is where they do all these marvellous things with minute wires which they pass through the groin and up into the heart. I was lucky enough to have the very best the NHS can offer. Dr Brian Clapp consultant cardiologist at Guys and St Thomas NHS Foundation Trust, London.
He is an expert in all types interventional cardiac procedures and uses the very latest cutting edge technology to perform what appears to be cardiological wizardry.
The procedure itself is normally done under X-ray guidance as a catheter is passed into the femoral vein in the groin. Then a wire is loaded with a device which looks like two tiny cocktail umbrellas, each the diameter of a 2p piece.
This is then passed through the catheter whilst tracked on screen and into the defect. When it reaches the defect the umbrella is deployed either side of it and once everything is positioned correctly the tubing is removed.
The Amplatzer device is the one Dr Clapp used in my op. It is inert and over time the body’s own tissues grow over it healing the hole. It usually takes around six months following the procedure. Although the procedure can be done without general anaesthetic some patients like me prefer to be knocked out!
The operation lasted about an hour and a half. When I woke up in my room my groin felt a bit sore but I felt fantastic. Apparently all had gone well and the device had implanted successfully. I got a wonderful night’s sleep and the next day I was able to walk out of hospital and get the bus home – I felt truly glad to be alive.
What is the evidence for PFO closure?
Although one in four adults has a PFO the prevalence of this particular defect amongst patients who have had a stroke with no known cause (cryptogenic stroke) is more like 60%.
Normally blood travels out of the right side of the heart through the lungs which filter out any debris and clots in the blood before it returns to the heart on the left side.
However, in people with a PFO when the hole opens up it allows the blood to travel straight from the right to the left side. Blood clots can then get through this opening to the brain potentially making them more at risk of stroke.
There is no clinical evidence to show conclusively that PFO closure has more benefit in reducing the recurrence of strokes than medication alone. However, there is a body of opinion which believes that in some cases where there has been no cause found for a stroke that there may still be a good reason to carry out percutaneous PFO closure.
The largest and most recent study into PFO closure was known as Closure 1 and compared stroke patients who remained on blood thinning medication alone and those who had PFO closure.
There was no significant benefit shown in those who had the PFO closure although the trial was limited to 2 years of follow up and used a device which has since been withdrawn. The RESPECT trial which is similar to Closure 1 is due to report towards the end of October.