Refractory angina or Intractable angina is a condition in which patients of heart disease continue to suffer from recurrent restricting angina, even though they are following the right medication plan.
Refractory angina is a chronic and incapacitating condition and often responds poorly to treatment. The patient might have also undergone essential invasive procedures such as angioplasty. Alternatively, the patient might have also been treated with stellate ganglion blocks and the like.
An estimated number of 300,000 to 900,000 patients in the United States have refractory angina, while 250,000 to 75,000 new cases are diagnosed every year.
Invasive interventions such as angioplasty or bypass surgeries are not always successful with patients of refractory angina. This is primarily due to the extent to which the arteries are narrowed.
There are two treatment plans that are now advised for patients of refractory angina. These are:
a) Aimed at improving flow of blood to the heart muscle.
b) Aimed at controlling pain
A) Treatments to improve blood flow
i) External enhanced counterpulsation – Three sets of balloons are wrapped around the legs and thighs. These are then inflated and deflated according to the ECG reading, in order to stimulate blood flow.
ii) Transmyocardial laser revascularization – A number of tiny channels are made through the heart muscle to improve the blood flow. The procedure involves a surgical chest incision, though with a less invasive catheter technique.
iii) Chelation therapy – The underlying theory of this approach is that chelation .i.e. removal of calcium ions, can make the fatty deposits in the coronary arteries disappear, leading to improvement in the blood flow.
B) Treatments to improve pain control
i) TENS (Transcutaneous electrical nerve stimulation): An electrode is placed over the site of the pain and another one opposite it on the back. The electrodes are connected to a nerve stimulator, producing a tingling sensation. Regular treatment with this has shown to reduce angina pain.
ii) Sympathectomy: This procedure dulls the nerves in the heart that act as pathways for pain, to relieve angina.
iii) Spinal cord stimulation: This involves passing an electrode through a catheter into the epidural space in the spinal column at chest height.
iv) Stress management and lifestyle changes: Stress management, relaxation and lifestyle changes, such as stopping smoking have known to lower angina threshold.
However, the exact success rate of each of these methods is subject to further research.
High Thoracic Epidural Analgesia (HTEA)
This technique for treatment of refractory angina was first researched in mid-1980s. An implantable Pot-a-Cath device was coupled to a tunneled epidural catheter. The system was designed so that the analgesic agent would be administered by intermittent bolus injection by the patient using a standard needle and syringe.
The patients who received HTEA were either awaiting a coronary artery bypass surgery, an angioplasty or were inoperable and typical cases of refractory angina. As per the research results, over 75% of patients reported improvement in quality of life and general health.
Though the cases of refractory angina are on an increase, the research conducted on the condition presents inadequate results. The treatment modalities suggested fall short of the desired results, leaving scope for further study.