Can Pulmonary Artery Hypertension Be Reversed?
Yes, pulmonary artery hypertension can be reversed with ease if proper management is done and time is the most crucial factor in deciding the prognosis of the disease. If on proper time patient is brought to the hospital then there are high chances that it can be reversed but in conditions where already the pulmonary function deteriorates to that extent where reversal is difficult then surely a person can even die from pulmonary artery hypertension.
The person who has progressed to New York Heart Association functional class 4, then there are high chances that a person may die within 6 months. Proper protocol must be followed while making a diagnosis.
The patient should undergo cardiac catheterization before initiating the therapy. Calcium channel blockers are the drug of choice but there is a criterion that after catheterization there should be at least a fall in mean arterial pressure by more than 10 mm Hg and along with that the final pressure should be less them 40 mm Hg. If this condition satisfies then only calcium channel blocker should be given. These patients need a high dose of amlopidine and nifedipine. Calcium channel blocker causes a rapid decrease in resistance.
Another drug which is used is endothelin receptor antagonist. Bosentan and ambrisentan are the second line of drug for pulmonary artery hypertension. Precaution to be taken includes monitoring of liver function test.
Phosphodiesterase Inhibitor For Pulmonary Hypertension
Apart from the 2 drugs another drug which can be used for pulmonary artery hypertension includes phosphodiesterase inhibitor which includes sildenafil and tadalafil. Mechanism of action is that they hydrolyse cyclic GMP in pulmonary vascular smooth muscles. Thus NO is increased and vasodilation occurs. The only main side-effect is a headache which should be kept in mind. Similarly, there are many other drugs which help in reversing the disease these include prostacyclin, iloprost. This is taken through inhalation route. The common side effects of this medication are flushing and cough. The major problem encountered by clinician while prescribing it is its half-life. It has got half-life of only 30 minutes and thus regular administration after 2 hours should be done to maintain the base level.
Epoprostenol for pulmonary artery hypertension is given via IV route. It must be given through a central vein and hence the placement of the permanent catheter is required to maintain the desired effect. Side effects include jaw pain, diarrhea, flushing but these side effects are easily tolerated by the patient.
Treprostinil is an analogue of the drug epoprostenol and can be given via IV, subcutaneous or inhalation route. Because of this property this drug can be used accordingly. But mostly the subcutaneous injection is avoided as it causes a lot of pain to the patient.
The intravenous prostacyclin is given only when patient failed to respond to all the treatment. Besides this, they are highly efficacious.
What Is The Desired Property Needed For Pulmonary Artery Hypertension Drugs?
- Platelet inhibition
- Inotropic effect
- Decreasing vascular growth
The drug which follows all these criteria is considered the ideal drug for usage. Prostacyclins fulfil the criteria and hence are prescribed for months. Dosage varies from 20-40 ng/kg per min for epoprostenol. The only problem is that intravenous catheterization requires a lot of monitoring and thus patient of pulmonary artery hypertension and the doctor both needs to be vigilant while the therapy is going on. And at times uneducated patient may face difficulty to deal with the catheter. One thing should be kept in mind is that abrupt withdrawal should not be done as it may cause rebound hypertension.
Several drugs have been tried but still, there is a debate on deciding the first lime regimen. If a patient fails to respond for 2 months then this is the time to act for another therapy.
The last resort of treatment for pulmonary artery hypertension is lung transplantation when while on prostacyclin patient is presenting with the symptom of right heart failure. So when all resort fails then the last resort is opted for reversing pulmonary artery hypertension. But time factor should always be kept in mind to prevent progression of the disease.