Pulmonary Hypertension in Rare Diseases - Overview

Introduction

Increased blood pressure in the pulmonary arteries is called pulmonary hypertension (PH). Pulmonary arterial hypertension, often known as PAH, is a rare and progressive form of pulmonary hypertension (PH). PAH is characterized by a narrowing and thickening of the pulmonary arteries, which results in greater blood circulation resistance and is the disease's most common characteristic feature. The pulmonary arteries and the heart's right ventricle both experience an increase in blood pressure as a response to the increased resistance. If this condition is not addressed, it could result in right ventricular failure and, ultimately, death over time.

What Are the Risk Factors?

At any age, a person is at risk for developing pulmonary hypertension. The danger increases as an individual gets older, especially as one reaches the age of 75. Other contributors to increased risk include the following:

• The state of having XX chromosomes at birth.

• Obstructive sleep apnea (characterized by periods of full or partial airway failure and a drop in oxygen levels or alertness from sleep) is associated with obesity.

• Pregnancy.

• A location at an extreme altitude.

• Use of Methamphetamine as a drug.

• Several kinds of cancer treatments.

• Viruses that cause infectious illnesses, including HIV and Hepatitis B or C.

• Asbestos and silica exposure.

• Tobacco use and smoking.

What Are the Symptoms?

Pulmonary hypertension symptoms may develop gradually over time. Symptoms may consist of:

• Fatigue (it is distinct from simple tiredness or drowsiness).

• Dizziness or syncope.

• Breathlessness from routine activity.

• Chest discomfort.

• Bluish hue of the lips or the epidermis (the outermost layer of skin).

• Inflammation of the legs, ankles, or abdomen.

• A rapid or pounding pulse rate.

• Hoarseness (difficulty producing noises when speaking).

• Sickness and vomiting.

• Wheezing (an indication that a person may have lung function difficulties).

Diagnosing pulmonary hypertension can be challenging because other illnesses might produce similar symptoms. However, symptoms of hypertension can develop when pressures are extremely elevated (180/120) and may include:

• Nasal bleeding.

• Poor headache.

• Chest discomfort.

• Respiratory complications.

What Are the Types of the Condition?

• Group 1: Pulmonary Arterial Hypertension (PAH): The first group consists of pulmonary vasculature pathologies that are similar to one another.

• Group 2: PH Due to Heart Disease of the Left Side: The second group consists of PH that is secondary to diseases of the left side of the heart, including systolic or diastolic heart failure, left-sided valvular diseases, congenital or acquired cardiovascular conditions that contribute to post-capillary PH, and others.

• Group 3: Pulmonary Hypertension Due to Lung Diseases: Pulmonary hypertension (PH) resulting from diseases affecting the lung epithelium or associated with hypoxia comprises the third group. Examples of such conditions include developmental lung disorders, obstructive lung disease, and restrictive lung disease.

• Group 4: CTEPH and Other Pulmonary Artery Obstructions: Chronic thromboembolic pulmonary hypertension (CTEPH), sarcoma or angiosarcoma, other malignant tumors (renal carcinoma, uterine carcinoma, germ cell tumors of the testis, and other tumors), nonmalignant tumors (uterine leiomyoma), arteritis without connective tissue disease, congenital pulmonary artery stenosis, and parasites comprise the fourth group.

• Group 5: Pneumonias of Uncertain or Multifactorial Etiology: It has hematologic disorders, such as chronic hemolytic anemia and myeloproliferative disorders; systemic disorders and metabolic disorders, such as pulmonary conditions, such as chronic renal failure with or without hemodialysis, and fibrosing mediastinitis; and complex congenital heart disease, such as segmental pulmonary(Pulmonary vascular remodeling and pulmonary hypertension (PH) primarily impact specific segments of the lung, rather than the lung as a whole.)

What Are the Diagnostic Methods?

PAH diagnosis needs several tests to determine the clinical class, underlying type, and functional and hemodynamic impairment.

• ECG: Electrocardiogram: Right ventricular hypertrophy, strain, and right atrial dilatation on the ECG may indicate PH. Idiopathic PAH patients have right ventricular hypertrophy and right axis deviation. PH screening with the ECG is insensitive and specific.

• Chest X-Ray: Some idiopathic PAH patients had abnormal chest radiography. Central pulmonary arterial dilatation contrasts with peripheral blood vessel loss. Advanced instances show right atrial and ventricular enlargement. Chest radiography may reveal moderate-to-severe lung illness or left heart problems causing pulmonary venous hypertension.

• ABG and Pulmonary Function Test: Pulmonary Function Test (PFT)s can detect lung problems. Idiopathic PAH is normal or slightly abnormal. PAH patients have low carbon monoxide diffusing capacity (DLCO), whereas PVOD patients have even lower values. ABGs usually demonstrate mild hypoxemia(a blood oxygen concentration that is abnormally low.) and hypocapnia(a blood condition with lower blood carbon dioxide levels). PVOD or COPD may cause severe hypoxemia.

• Fitness Testing: Exercise distends pulmonary arteries and arterioles and recruits underused vascular beds. Thus, in health, pulmonary artery pressure rises minimally with increased blood flow, and pulmonary vascular resistance lowers due to remodeled vasculature. Failure to perfuse the ventilated lung increases physiologic dead space and ventilatory requirement; failure to increase cardiac output in response to exercise causes early lactic acidosis, increasing acid ventilatory drive; exercise-induced hypoxemia increases hypoxic ventilatory drive.

• TTE—Transthoracic Doppler-Echocardiography: TTE screens suspected PH patients non-invasively. TTE estimates pulmonary artery systolic pressure (sPAP). PAP is estimated from tricuspid regurgitation jet peak velocity. The inferior vena cava diameter and respiratory variation estimate right atrial pressure. Tricuspid regurgitation velocity can be compared to healthy values to diagnose PH echocardiographically. Consider age, sex, and body mass. This technique reduces cumulative error but is less closely tied to the mPAP-based hemodynamic definition of PH.

TTE can also distinguish pulmonary hypertension causes. TTE can detect post-capillary PH-causing left heart valvular and myocardial illnesses and congenital heart diseases with systemic-to-pulmonary shunts.

• Perfusion/Ventilation Scan: Chronic thromboembolic pulmonary hypertension (CTEPH) elevated blood pressure in the pulmonary arteries screening requires ventilation/perfusion lung scans. V/Q (ventilation (V) to perfusion (Q)lung scans detect and eradicate CTEPH.

• High-Resolution Chest CT: HRCT can reveal underlying lung parenchyma diseases such as pulmonary emphysema or interstitial lung disease. Pericardial effusions and pulmonary artery hypertrophy can be seen on chest HRCT. Contrast HRCT of the pulmonary arteries may demonstrate full arterial occlusion, vascular cut-offs, intimal abnormalities, integrated thrombus forms, bands, and webs in CTEP. This method also detects bronchial artery collaterals. Proximal pulmonary obstruction shows considerable and accessible organized fibrous tissue in segmental or subsegmental arteries. Pulmonary angiography can distinguish proximal from distal blockages.

• Pulmonary Angiography: Pulmonary angiography can identify surgically accessible CTEPH. CTEPH angiography shows full occlusion, band and webs, and intimal abnormalities. Fibrosing mediastinitis may benefit from pulmonary angiography.

• Cardiac MRI: Cardiac MRI can assess right ventricular size and morphology and form non-invasively. It non-invasively measures cardiac output, stroke volume, pulmonary artery distensibility, and right ventricular mass. Poor prognosis is related to decreased stroke volume, increased right ventricular end-diastolic volume, and decreased baseline. Thus, cardiac MRI may be a non-invasive method for PAH severity assessment at baseline and follow-up.

• Abdominal Ultrasound: To rule out portal hypertension or liver disease, all PH patients should get an abdominal ultrasound. A higher gradient between free and occluded hepatic venous pressure during RHC confirms portal hypertension.

• Lab Tests: Screening for HIV, hepatitis B, and C should include serological tests. PAH patients often have hyperthyroid dysfunction or autoimmune thyroiditis.

• Right-Heart Catheterization: Right-heart catheterization is needed to confirm PH with a resting mPAP of 25 mmHg and a normal PCW (Pressure in the pulmonary capillary wedge). PAH prognosis is affected by elevated mean right atrial pressure, decreased CO, and mixed venous oxygen saturation (SVO2).

• Disease Severity: PVOD and CTD-associated PAH (sometimes with venous involvement) have a worse prognosis than idiopathic PAH. Congenital systemic-to-pulmonary shunt-associated PAH progresses more slowly than idiopathic PAH as the underlying illnesses may affect the outcome.

What Are the Treatment Methods?

Pulmonary hypertension arises due to the obstruction of pulmonary arteries by blood clots; healthcare providers may propose the administration of anticoagulant medications as a preventive measure against the formation of additional clots. Additionally, patients may be presented with the option of undergoing a surgical procedure referred to as a pulmonary endarterectomy. Treatment or a combination of treatments will depend on several factors, including the type of pulmonary hypertension one has, its cause, and the severity of the symptoms. Treatments consist of:

• Medications - Anticoagulant medications, such as Warfarin, to prevent blood clots; diuretics to eliminate excess fluid in the body due to heart failure.

• Home Oxygen Therapy- Inhaling air with a higher concentration of oxygen than normal Digoxin – can improve the symptoms by strengthening the heart muscle contractions and reducing the heart rate.

Other occasionally employed treatments include:

• Endothelin Receptor Antagonists- Such as Bosentan, Ambrisentan and Macitentan phosphodiesterase 5 inhibitors – Sildenafil And Tadalafil prostaglandins – Epoprostenol, Iloprost and Treprostinil Soluble Guanylate Cyclase Stimulators – such As Riociguat Calcium Channel Blockers – Nifedipine, Diltiazem, Nicardipine, and Amlodipine.

• Surgical and Invasive Treatments for Pulmonary Hypertension- Some individuals with pulmonary hypertension might require surgery. Surgical procedures in use today include:

• Pulmonary Endarterectomy- Patients who have chronic thromboembolic pulmonary hypertension (a disease where high blood pressure in the pulmonary arteries is caused by long-term blood clots that block the flow of blood through the lungs.) undergo this surgical procedure to have pre-existing blood clots removed from the pulmonary arteries.

• Balloon Pulmonary Angioplasty- A new procedure in which a tiny balloon is guided into the arteries and inflated for a few seconds to push the blockage aside and restore blood flow to the lung. It has been shown to lower blood pressure in the lung arteries, improve breathing, and increase the ability to exercise.

• Atrial Septostomy- A small hole is made in the wall between the left and right atria.

• Transplant- In extreme cases, a lung transplant or a heart-lung transplant may be required; however, this type of surgery is rarely performed because effective medications are available.

What Are the Complications?

The following issues, among others, may arise as a result of pulmonary hypertension.

• Pneumatic artery blood clots.

• The right side of the heart's increased pressure has caused liver damage.

• The fluid-filled sac surrounding the heart is known as a pericardial effusion.

• Anemia is often known as low hemoglobin or low red blood cell count.

• Inconsistent heartbeat.

• Blocks in the bundle of branches cause the electrical impulse that starts the heartbeat to take longer.

• Bleeding inside the lungs.

• Issues from pregnancy, such as heart attacks, strokes, respiratory failure, and cardiac arrest.

• Shortened lifespan.

How Can the Condition Be Prevented?

There are several cases in which pulmonary hypertension cannot be avoided. Nevertheless, some actions can be taken to lessen the likelihood of having the illness. Some strategies are as follows:

• Bringing the patient's high blood pressure under control.

• Maintaining a careful eye on patients with coronary heart disease and managing the condition.

• Managing or monitoring chronic liver illness or chronic lung disease, both of which are caused by smoking tobacco.

• Maintaining a diet that is healthy for the heart is important.

• Giving up smoking and other forms of tobacco use.

Conclusion

Pulmonary hypertension (PH) is characterized by pulmonary artery pressure (mPAP) of 25 mmHg or higher, as determined through right heart catheterization. Enhanced comprehension of this condition facilitates the advancement of therapeutic interventions designed to enhance overall well-being, reduce disease burden, and decrease mortality rates. The routine management of patients with pulmonary hypertension (PH) should encompass physiotherapy interventions that enhance physical activity, foster functional independence, and facilitate self-management.