Secondary pulmonary arterial hypertension

The ‘pulmonary hypertension’ denotes various conditions in which pulmonary arterial pressure is elevated above normal.

A mean pulmonary artery pressure >25 mm Hg at rest or pulmonary artery systolic pressure >35 mm Hg is considered abnormal.

Pulmonary arterial hypertension has been observed in all connective tissue disease, but most frequently in systemic scleroderma (SSc).

It is and has often been classified into two separate categories: primary pulmonary (arterial) hypertension, presently more often called idiopathic pulmonary arterial hypertension (iPAH) and secondary pulmonary arterial hypertension.

Secondary pulmonary arterial hypertension is more common than iPAH. Secondary pulmonary arterial hypertension is the common pathophysiologic mechanism leading to cor pulmonale in patients with underlying pulmonary disease (e.g. chronic obstructive pulmonary disease - COPD, pulmonary embolisms)
Secondary pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension

Primary arterial hypertension is and has often been classified into two separate categories: primary pulmonary (arterial) hypertension, and secondary pulmonary arterial hypertension.

The term ‘primary’ pulmonary hypertension was replaced by ‘idiopathic’ pulmonary hypertension and when there was a genetic basis, ‘familial’ pulmonary hypertension.

Primary hypertension that occurred along with other conditions was referred to as ‘associated’ pulmonary hypertension.

Idiopathic pulmonary arterial hypertension is highly morbid disease characterized by progressive obliteration of precapillary arterioles.

The disease manifested by progressive pulmonary vascular remodeling, compromised pulmonary blood flow and right heart failure.

Idiopathic pulmonary arterial hypertension is rare, occurring in one to two cases per one million people per year, with an overall prevalence estimated at 1300 per one million.

According to World Health Organization (WHO) estimated, there are 5000 patients with Idiopathic pulmonary arterial hypertension in the United States and Europe. However, the prevalence may be increased because of heightened awareness and early recognition in minimally symptomatic patients.
Idiopathic pulmonary arterial hypertension

What are the symptoms of pulmonary hypertension?

The diagnosis of pulmonary hypertension is usually made four to seven years after the diagnosis of portal hypertension. In addition, the risk of developing pulmonary hypertension increases with the duration of portal hypertension.

With chronic pulmonary hypertension, patients present with progressive dyspnea and fatique. Dyspnea is caused by decreased CO (cardiac output) and ventilation/perfusion mismatch.

Syncope, due to atrial and ventricular arrhythmias, occurs in one third of patients. Syncope is due to a fixed CO with the inability of the heart to respond to a demand for increased output.

The reduction the systolic pressure gradient across the right ventricular (RV) myocardium and increased RV oxygen demand caused by RV walls stress may result in symptoms of angina in one-third of patients.

During physical examination of the parturient with pulmonary hypertension, a RV heave may be present and an ejection click may be heard over the pulmonic area.
What are the symptoms of pulmonary hypertension?

What do you know about pulmonary hypertension

Pulmonary (PULL-mun-ary) arterial hypertension (PAH) is continuous high blood pressure in the pulmonary artery. The average blood pressure in a normal pulmonary artery is about 14 mmHg when the person is resting. In PAH, the average is usually greater than 25 mmHg.
PAH is a serious condition for which there are treatments but no cure. Treatment benefits many patients.

The pulmonary arteries are the blood vessels that carry oxygen-poor blood from the right ventricle (VEN-trih-kul) in the heart to the small arteries in the lungs. In PAH, three types of changes may occur in the pulmonary arteries:

*The muscles within the walls of the arteries may tighten up. This makes the inside of the arteries narrower.

*The walls of the pulmonary arteries may thicken as the amount of muscle increases in some arteries. Scar tissue may form in the walls of arteries. As the walls thicken and scar, the arteries become increasingly narrow.

*Tiny blood clots may form within the smaller arteries, causing blockages.

There is less room for the blood to flow through these narrower arteries. The arteries may also stiffen. Over time, some of the arteries may become completely blocked.

The narrowing of the pulmonary arteries causes the right side of heart to work harder to pump blood through the lungs. Over time, the heart muscle weakens and loses its ability to pump enough blood for the body's needs. This is called right heart failure. Heart failure is the most common cause of death in people with PAH.

There are two types of PAH:
*Primary pulmonary arterial hypertension (PPAH) is inherited or occurs for no known reason.
*Secondary pulmonary arterial hypertension (SPAH) either is caused by or occurs because of another condition. The conditions include chronic heart or lung disease, blood clots in the lungs, or a disease like scleroderma (skler-o-DER-ma).

About 300 new cases of PPAH are diagnosed in the United States each year. SPAH is much more common.

Doctors have learned a lot about PAH in recent years. More treatments are now available. Researchers are also studying several promising new treatments that may prolong lives as well as improve the quality of life for people living with PAH.
What do you know about pulmonary hypertension

Pulmonary hypertension associated hypoxemia

Hypoxemia, with or without respiratory acidosis may be the most important factor cause secondary pulmonary hypertension.

What is hypoxemia? Hypoxemia is defined as an oxygen tension in arterial blood that is below normal. Hypoxemia usually leads to hypoxia, a decrease in oxygen supply to the tissue, which can also be caused by problem outside the respiratory system.  

Hypoxemia, caused by alveolar hypoventilation, vascular obstruction primary cardiac disease and conditions causing acquired cardiac disease.

Alveolar hypoventilation can result from diseases caused by alveolar destruction or from disorders that prevent the chest wall from expanding sufficiently to allow air into the alveoli.

Hypoxemia resulting from this ventilation-perfusion mismatch also causes vasoconstriction, furthermore increasing vascular resistance and resulting in pulmonary hypertension.

Hypoxemia may cause an increase in ventilation and cardiac output as the body compensates. By increasing the oxygen content of the arterial blood, the muscle requirements of the pulmonary and cardiovascular systems are reduced.
Pulmonary hypertension associated with lung disease and/or hypoxemia

Pulmonary hypertension

Pulmonary hypertension is a severe, potentially fatal disease that affects lung and heart. Normal pulmonary artery pressure in systole is 20 to 30 mm Hg and in diastole about 10 mm Hg.

Pulmonary hypertension is defined as a mean pulmonary artery pressure exceeding 25 mm Hg and a mean pulmonary arterial pressure above 18 mm Hg.

It is symptomatically characterized by shortness of breath, fatigue and fainting which is severely exacerbated through exertion due to an increase in blood pressuring the lung vasculature finally leading to a progressive worsening of hemodynamic function, right ventricular hypertrophy, right heart insufficiently and finally right heart failure.

It is a group of conditions with multiple causes rather than a single one. Pathogenesis amnd management doffer among entities.

The path physiological mechanisms that may result in pulmonary hypertension are as follows:
1. Increased pulmonary blood flow
2. Prolonged left atrial hypertension
3. Organic vascular obstruction
4. Pulmonary vasoconstriction

Pulmonary hypertension can be grouped into to one of five general categories based on similar pathophysiologic processes and treatment
1. Pulmonary arterial hypertension (PAH)
2. Pulmonary venous hypertension
3. Pulmonary hypertension associated with lung disease and/or hypoxemia
4. Pulmonary hypertension caused by chronic thrombotic or embolic disease
5. Miscellaneous disorders associated with pulmonary hypertension 

Pulmonary arterial hypertension as a group of pulmonary hypertension is rare, progressive, currently incurable and terminally fatal. With a prevalence of about 15-50 patents per one million inhabitants the disease is classified as an ‘orphan disease’.

The most common systems associated with pulmonary hypertension are dyspnea, tachypnea, and chest pain. Decreased exercise tolerance is a frequent complaint, and syncope and light headedness are reported less often.
Pulmonary hypertension