Clearly the lung is the organ responsible for gas exchange but many don’t realise it is also acting as a huge blood filter capturing thrombus (pulmonary emboli) and neutralising chemical toxins and signallers such as prostaglandins and interlukins, just to name a few.
Reversal of the PFO shunt(R-> L) towards the arterial side occurs during any valsalva manoeuvre such as straining, snoring or coughing resulting in a flood of material bypassing the lung filter.
In some large PFOs the shunt is always reversed. Solid thrombus, microscopic platelet aggregates and metabolites can affect organ function and even cause infarction and ischaemia in organs such as the brain, heart, kidneys and even leg claudication.
This is a huge topic in itself. The following information is restricted to Cryptogenic CVA/TIA and Migraine with Aura.
There are ways to determine if the PFO in a young cryptogenic embolic victim is simply an innocent bystander, or if it has a high probability of being the conduit for paradoxical embolic event.
The details in this regard are beyond the scope of this introductory document.
The RESPECT trial showed if a patient received a PFO closure after a cerebral event they had less chance of a secondary event compared with medical therapy. This avoids the need for lifelong warfarin/ NOAC therapy.
The classical migraine is now known to be a risk factor for an early cardiovascular event as evidenced by the recently released US Nurses study.
It is present in 10-15% of the population. In fact, MRI studies have shown a significant number of young females with migraine have had an asymptomatic brain ischaemic event.
Studies have also shown a significant number of severely debilitated migraineurs will have a large PFO.
To date, randomised studies have not given us a clear answer as to whether closure is better than medical therapy.
This has been largely due to poor patient selection techniques and difficulty in conducting the trials as many randomised patients have proceeded to closure outside the study protocol.
Also closure rates have been low due to first generational devices and even today some operators have non-closure rates as bad as 20% long term.
Heartbrain Private Clinic follows a specific assessment and closure protocol and follows up all patients with the gold standard cTCD to note non-closure rates as little as 1% in over 500 cases.
Some of our work was presented at a major international cardiovascular conference in Europe and showed a complete cure rate of 85% and a total response rate of 98% (defined as complete cure or, little or no disability) at two years.
These patients were carefully selected, severely disabled patients following a strict assessment process. Many of our patients, after years of non-participation have returned to the work force or study within months of closure.
Patients usually withdraw migraine prophylactic drugs in the months following their procedure.
Any young patient who has had a thromboembolic event without an obvious cause such as atherosclerosis and major CV risk factors. Specifically CVA/TIA, amourosis fugax, myocardial infarct, peripheral or any central embolic event such as mesenteric ischaemia and renal infarction.
NB: Remember Atrial Fibrillation occurs commonly in patients with atrial shunts and independently increases the thromboembolic risk.
Heartbrain Private Clinic is a neuro-cardiac clinic with a dedicated group of senior cardiac specialists, technicians, nurses, psychologists and scientists who have a specific interest in the implications and impacts of large PFOs on the human condition.
We strive to deliver a high standard of patient care and outcomes through highly structured protocols and good science.
We are involved in ongoing research and trials in association with a not-for-profit charity known as the PFO Research Foundation Ltd.