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Conferences & Courses
Guam Memorial Hospital
Mortality and Morbidity Conference
June 24, 1998
Pulmonary Hypertension
by Rosie Villagomez, M.D.
What is pulmonary hypertension (PH)?
Pulmonary hypertension is a rare lung disorder occurring as a
primary idiopathic disease or as a complication of a large number of respiratory and
cardiac diseases. In PH, the pressure in the pulmonary artery rises above normal levels
and may become life threatening. The normal mean pulmonary artery pressure is
approximately 12 mm Hg. Pulmonary hypertension is present when mean PA pressure exceeds 20
–25 mm Hg at rest or 30 mm Hg during exercise.
Are there different types
of PH?
PH can occur with or without an identifiable cause.
When it occurs associated with an identifiable cause, it is a secondary pulmonary
hypertension. In the absence of a known cause it is called primary pulmonary hypertension
(PPH). Females outnumber males in PPH, with ratios of 3:1 or 4:1 and can occur at any age,
though it primarily affects young to middle-aged women. It occurs sporadically or with a
familial pattern suggestive of an autosomal dominant inheritance with variable penetrance.
PPH is characterized by extensive remodeling of the pulmonary vasculature, with consequent
hypertrophic changes in the right ventricle.
What is secondary PH?
Secondary pulmonary hypertension can result from numerous causes. There are
different ways to categorize secondary PH. One is based on its pathophysiology:
precapillary, passive and reactive. The four categories I will use are 1)Pulmonary venous
hypertension; 2) Thromboembolic disease; 3) Chronic hypoxia; and 4) Right to left shunt.
See attached figure on the anatomic approach to the differential diagnosis.
Pulmonary venous hypertension is back pressures from the high pressures at any
point downstream from the pulmonary arteries. It can be caused by conditions such as
coarctation of the aorta, aortic stenosis and regurgitation, HOCM, mitral stenosis and
regurgitation.
Obstruction of the pulmonary arteries by thromboembolic disease is very common,
although this usually causes acute pulmonary hypertension and is often reversible. Of
course, chronic pulmonary embolism is possible, and worldwide, schistosomiasis is the
leading cause of chronic PH. These blood flukes penetrate the skin and are carried by the
blood to the liver where they mature into adult parasites. If the ova enter the venous
circulation, they lodge in pulmonary arterioles where they produce an inflammatory lesion
and granulomas. This causes obstruction of the pulmonary arterioles and PH.
Disorders of ventilation that can cause this include pulmonary vasoconstriction
or an anatomic restriction of the pulmonary vascular bed. Pulmonary vasoconstriction can
occur in response to hypoxia and acidemia particularly when produced by hypercapnia. In
COPD, hypoxemia and acidemia are the main determinants of pulmonary hypertension. It
occurs mainly in patients with PaO2 less than 50 and PaCO2 greater than 45. Hypoxia
secondary to high altitude, primary central hypoventilation, obstructive sleep apnea,
obesity-hypoventilation syndrome, and myasthenia gravis are other causes. Anatomic
restriction of the pulmonary vascular bed may be due to sarcoidosis, progressive systemic
sclerosis, interstitial fibrosis, cystic fibrosis, emphysema and ARDS.
Finally, certain congenital heart disease can lead to PH. The most frequent
congenital lesions are those characterized by a left to right shunt such as VSD, PDA and
ASD. The development of severe pulmonary hypertension in patients with these cardiac
defects is termed Eisenmenger reaction. As the pulmonary vascular resistance increases,
the magnitude of the left to right shunt increases. On examination, there is a systolic
pulmonic murmur and usually fixed splitting of the second heart sound. EKG indicates a
right ventricular volume overload and CXR can show increased pulmonary vascular markings,
and enlarged right ventricle. A patient with Eisenmenger’s syndrome is a special case
that may be amenable only to transplantation because of the irreversible nature of the
high pulmonary pressures and reversed central shunt.
Today’s patient had pulmonary hypertension secondary to ASD
What are the common
symptoms of PH?
The onset of the condition is usually insidious, but
depends on the underlying cause. The most common symptoms of PH regardless of cause are
dyspnea with exertion, chest discomfort and fatigue. Because PPH is usually seen in young
to middle aged women, the symptoms are often ascribed to functional or emotional causes.
As a result, delay in diagnosis is common. Late in the disease, dyspnea occurs at rest.
Patients with PH may experience syncope, dizziness and lower extremity edema. In patients
with right to left shunts, the clinical findings and symptoms of VSD and PDA usually lead
to their detection in childhood, but the manifestations of ASD as in today’s patient,
may be subtle therefore this lesion can remain undetected until adulthood. The primary
symptom of ASD is decreased exercise tolerance.
How do you evaluate
patients with suspected PH?
*Patient history and examination
*Chest X-ray
*EKG
*ABG
*Coagulation evaluation
*Serologic tests
*Echocardiography and Doppler ultrasound
Transesophageal echocardiography
*PFT with exercise testing
VQ scan and pulmonary angiography
CT scan of the chest
Invasive hemodynamics
Sleep studies
Pulmonology, Rheumatology, Transplant and Surgical consultation
Home health nursing evaluation
How do you treat PH?
If possible, the underlying cause should be treated.
If the underlying cause is not treatable, or is unknown, then continuous oxygen therapy,
anticoagulation, high dose calcium channel blockers, inhaled nitric oxide, continuous
prostacyclin infusion and lung only or combined heart-lung transplantation may all be
considered.
What is the prognosis of
PH?
The course of PPH is poor with gradual decline.
Patients usually deteriorate steadily throughout the course of the disease with reduced
life expectancy. Non-transplanted patients have a probability of survival of 70-75% at one
year, 50-60% at two years, 40-55% at three years, 30-40% at 4 years, and 20-30% at five
years (mean survival is less than 3 years from the time of diagnosis). Recent advances in
the medical management have shown that some patients may have an extremely good outcome
depending on the responses to high doses of calcium channel blockers. Anticoagulants are
also associated with improved survival and prostacyclin is showing great promise in
patients refractory to conventional therapy.
References
1. Bethlem, EP; Schettino G de P, Carvalho, CR. Pulmonary
schistosomiasis. Current Opinions in Pulmonary Medicine. 1997 Sep 3 (5) 361-5.
2. de Leon, FC; Britt, EJ. The noninfectious respiratory complications of infection
with HIV. Current Opinions in Pulmonary Medicine. 1995 May; 1 (3) 223-33.
3. Foster, E. Congenital heart disease in adults. Western Journal of Medicine.
1995 Nov 163 (5) 492-8.
4. Mesa, RA, Edell, ES, Dunn, WF, Edwards, WD. Human immunodeficiency virus
infection and pulmonary hypertension: two new cases and a review of 86 reported cases.
Mayo Clinic Proceedings 1998 Jan 73 (1) 37-45.
5. Morales, D, Loscalzo, J. Pulmonary hypertension: newer concepts in diagnosis and
management. Clinical Cardiology 1997 Aug 20 (8) 676-82.
6. Rich, S. Medical treatment of primary pulmonary hypertension: a bridge to
transplantation? American Journal of Cardiology. 1995 Jan 19; 75 (3) 63A-66A.
7. Rubin, LJ. Primary pulmonary hypertension. New England Journal of Medicine.
1997 Jan 9; 336 (2) 111-7.
8. Rubin, LJ. Pathology and pathophysiology of primary pulmonary hypertension.
American Journal of Cardiology. 1995 January 19; 75 (3) 51A-54A.
9. Vongpatanasin, W, Brickner, ME, Hillis, LD, Lange, RA. The Eisenmenger syndrome
in adults. Annals of Internal Medicine. 1998 May 1; 128 (9) 745-55
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