Pulmonary hypertension in its simplest sense refers to an elevation in the pulmonary arterial pressure above nonnal. Publisl~ed normal levels of pulmonary arterial pressures have come from cardiac catheteiizations performed in youilg subjects at rest without any evidence of carcliopulmonary disease. The upper limit of normal for pulmonsuy artery mean pressure is 19 mmHg. However, upper normal limit derived from ECHO-Doppler evaluation in nonnal general population may be slightly higher.
a)Causes of Pulmonary Hypertension
The classification of causes of pulmonay hypertension modified from new classification developed at the World Symposium on Pulmonary Hypertension co-sponsored by World Health Organization in 1998 is given in the table (modified).
1. Pulmonary arterial hypertension
I Primary Pulmonary Hypertension: (a) familial
2 Associated with: (a) connective tissue disease; (b) congenital heart disease; (c) portal hypertension; (d) HIV infection; (e) drugs/toxins/anorexigens and others
3 Persistent pulmonary hypertension of new born
4 Pulmonary vaso-occlusive diseases
5 Pulmonary capillary hemangiomatosis
2.Pulmonary venous hypertension
1 Left sided heart disease
2 Left sided valve disease
.3 Extrinsic compression, fibrosing alveolitis etc.
Pulmonary hypertension due to respiratory disorders
1 Chronic obstructive lung disease
2 Interstitial fibrosis etc.
4.Pulmonary hypertension due to thromboembolism
5. Pulmonary vascular disease: sarcoidosis, schistosomiasis etc.The World Health Organization Fu~lctional Classificaiion of Pulmonary Hypertension has been inodified and published into four classcs similar to New York Heart
Association Functional Clnssil'ication.
The important symptonls of pulmonal-y hypertension are exertional dyspnoea, edema,angina, syncope and symptoms of underlying disease.
Clinical examination may reveal large 'a' waves in the jugular venous pulse, left parasternal heave, systolic pulsation of dilated pullnonary artery in 2nd left intercostals space, ejection click, loud pulmonary component of second sound, short systolic flow rnurmur in pulmonary area, and tricuspid regurgitation murmur Cyanosis is a lalc feature.
The investigations that help in thc diagnosis arc, chest X-ray, elcctrocardiogranl,which reveals right ventricular hypertroplly, right atrial enlargement, right axis deviation. The echocardiography helps in estimation of pulmonary artery pressure and also helps in the diagnosis of etiology. Other investigations include radionuclide ventriculography, lung scintigraphy, pulmonary function tests, colnputed tolnography,pulmonary angiography, and cardiac catheterization studies.Although pl-eg~lancy may be associated with any of the causes of pulmonary hypeitension, two important causes need to be discussed.
Primary Pullnonary Hypertension (PPH)
Primary Pultnonary Hypertension is the occurrence of pulmonary hypertension of unexplained etiology. Though the etiology is unknown, it represents final common pathway from multiple biological abnormalities within the pulmonary circulation.Abnormality in the pulmonary endothelial cell f~rnction contributes to development of the PPH. Abnormal vasoconstrictive tendency in predisposed individuals has been found.Reduced nitric oxide synthesis in the endothelium has been demonstrated. Endothelin may also play a part in the development of pulmonary hypertension. Intimal proliferation and vascular occlusion secondary to increased growth factors have been implicated. Wide spread in situ thrombosis of small pulmonaly arteries has also been implicated.
PPH and Pregnancy: PPH is defined as elevation of mean pulmonary artery pressure greater then 25 mmHg in the absence of demonstrable cause. Pulmonary vasoconstriction, medial hypertrophy and dysfunctional pulmonary vascular endothelium in situ thtombus are believed to contribute.PPH associated with pregnancy ca~ries a high maternal mortality rate of about 50-60 per cent. Even though pre conceptional symptoins are minimal, deterioration can occur rapidly during pregnancy, usually in second or third trimester. Usual manifestations include fatigue, exertional dyspnoea, syncope, chest pain, palpitations,cough, heinoptysis and leg edema. Death usually occurs few hours to several days after delivery and related to sudden death or progressive light ventricular failure. The exact cause of death is not clear but light ventricular ischemia and failure caused by increase in pulmonary resistance after delivery, cardiac arrhythmias and pulmonary embolism are possible mechanisms. High incidence of prematuiity of fetus, fetal growth retardation and fetal loss are associated with PPH.Woinen with PPH are advised against pregnancy. If pregnancy occurs, early termination is advised. Incidence of premature delivery is common and should be anticipated. Where PPH is not diagnosed until late in pregnancy an elective delivery is preferred.
Management of Pregnancy and Delivery
There is increased iisk of thl~omboembolism diring pregnancy and anticoagulants are found to be beneficial in PPH, anticoagulants are recommended throughout pregnarlcy or atleast during third trimester and delivery. Many have recommended vaginal delivery under epidural anesthesia. Pulmonaiy vasoconstriction is a prominent feature and hence vasodilators are to be used including oxygen administration, nitric oxide,epoprostenol and iloprost in short term and calcium antagonists in the long term.Nitric oxide has been used in the pre and post delive~y management of PPH in pregnancy. Epoprostenol is a naturally occu~ring prostaglandin and a potent vasodilator. It affects vascular remodeling and inhibits platelet aggregation. Iloprost is a synlhetic analogue of epoprostenol with improved metabolic and chemical stability,which decreases pulmonary arterial pressure and pullnonary vascular resistance,increases cardiac output and has minimal effect on systemic arterial pressure.Successful maternnl and fetal outcome with epoprostenol therapy during pregnancy,caesarian section, and post parlum, in a patient with PPH has been reported. However,greater mortality has been reported from caesarian section and not with vaginal delivery.
The other drug [hat is useful is sildenafi'l, which is a phosphodiesterase type-5 inhibitor- a promising drug in treating pulmonaly hypertension. Similarly endothelin receptor blocker - bosentan is also used to treat pulmonary hypertension. The data on their use in pregnancy is not available at present.
Eisenmenger's Syndrome
Eisenmengers syndrome is a term coined by Paul Wood and is defined as pulmonary vascular obstructive disease that develops as a consequence of a large pre-existing left-to-right shunt such that pulmonary artery pressure approaches systemic levels andthe direction of flow becomes bi-directional or right-to-left. The congenital defects include Atiial Septal Defect (ASD), Ventricular Septal Defect (VSD) and Patent Ductus Arteriosus (PDA) and complex defects like atrio-ventricular canal defects,truncus arteriosus, aorto-pulmonary window and univentricular heart.
In pregnancy, Eisenmetlger's syndrome carries high risk of maternal morbidity and 'mortality of approximately 40 per cent. Mortality usually occurs within first few days or weeks after delivery preceded by clinical and henlodynamic deterioration. Diffuse fibrinoid necrosis of pulmonary arterioles and puln~onauy embolism has been reported. Eisenmenger's syndrotlle is also associated with poor fetal out come with fetal loss, prematurity, fetal growth retardation and perinatal death.
Management: Patients with Eisenmenger's syndromes should be advised against pregnancy because of high risk. Early abortion is advised to patients who are already pregnant, Management of patients who coine late or who decide to continue pregnancy, include close follow-up to detect early deterioration. Anticoagulation is indicated in the third trimester to prevent thromboembolic complications and continued for a few weeks after delivery.Patients with Eisenmenger's syndrome need hospitalization for close monitoring since premature delivery is common, admissioil is advised if there is my sign of uteiine activity. Spontaneous labor is preferred to induction. Monitoring of blood pressure,electrocardiogran~, and blood gas are essential during labor. Most patients may tolerate vaginal delivery, however, illtempt should be made to shorten the second stage of labor by use of forceps or vacuuill extraction. In some patients planned caesarian section is better than emergency caesarian section and hence proper assessment is needed. Inhalation of nitric oxide has been used successfully to reduce pulmonary artery prcssure apd improve oxygen saturation during labor and early peurperium.The use bS sildenafil and bosentan in pregnancy for treatment of pulmonary hypertension is not available at present.
a)Causes of Pulmonary Hypertension
The classification of causes of pulmonay hypertension modified from new classification developed at the World Symposium on Pulmonary Hypertension co-sponsored by World Health Organization in 1998 is given in the table (modified).
1. Pulmonary arterial hypertension
I Primary Pulmonary Hypertension: (a) familial
2 Associated with: (a) connective tissue disease; (b) congenital heart disease; (c) portal hypertension; (d) HIV infection; (e) drugs/toxins/anorexigens and others
3 Persistent pulmonary hypertension of new born
4 Pulmonary vaso-occlusive diseases
5 Pulmonary capillary hemangiomatosis
2.Pulmonary venous hypertension
1 Left sided heart disease
2 Left sided valve disease
.3 Extrinsic compression, fibrosing alveolitis etc.
Pulmonary hypertension due to respiratory disorders
1 Chronic obstructive lung disease
2 Interstitial fibrosis etc.
4.Pulmonary hypertension due to thromboembolism
5. Pulmonary vascular disease: sarcoidosis, schistosomiasis etc.The World Health Organization Fu~lctional Classificaiion of Pulmonary Hypertension has been inodified and published into four classcs similar to New York Heart
Association Functional Clnssil'ication.
The important symptonls of pulmonal-y hypertension are exertional dyspnoea, edema,angina, syncope and symptoms of underlying disease.
Clinical examination may reveal large 'a' waves in the jugular venous pulse, left parasternal heave, systolic pulsation of dilated pullnonary artery in 2nd left intercostals space, ejection click, loud pulmonary component of second sound, short systolic flow rnurmur in pulmonary area, and tricuspid regurgitation murmur Cyanosis is a lalc feature.
The investigations that help in thc diagnosis arc, chest X-ray, elcctrocardiogranl,which reveals right ventricular hypertroplly, right atrial enlargement, right axis deviation. The echocardiography helps in estimation of pulmonary artery pressure and also helps in the diagnosis of etiology. Other investigations include radionuclide ventriculography, lung scintigraphy, pulmonary function tests, colnputed tolnography,pulmonary angiography, and cardiac catheterization studies.Although pl-eg~lancy may be associated with any of the causes of pulmonary hypeitension, two important causes need to be discussed.
Primary Pullnonary Hypertension (PPH)
Primary Pultnonary Hypertension is the occurrence of pulmonary hypertension of unexplained etiology. Though the etiology is unknown, it represents final common pathway from multiple biological abnormalities within the pulmonary circulation.Abnormality in the pulmonary endothelial cell f~rnction contributes to development of the PPH. Abnormal vasoconstrictive tendency in predisposed individuals has been found.Reduced nitric oxide synthesis in the endothelium has been demonstrated. Endothelin may also play a part in the development of pulmonary hypertension. Intimal proliferation and vascular occlusion secondary to increased growth factors have been implicated. Wide spread in situ thrombosis of small pulmonaly arteries has also been implicated.
PPH and Pregnancy: PPH is defined as elevation of mean pulmonary artery pressure greater then 25 mmHg in the absence of demonstrable cause. Pulmonary vasoconstriction, medial hypertrophy and dysfunctional pulmonary vascular endothelium in situ thtombus are believed to contribute.PPH associated with pregnancy ca~ries a high maternal mortality rate of about 50-60 per cent. Even though pre conceptional symptoins are minimal, deterioration can occur rapidly during pregnancy, usually in second or third trimester. Usual manifestations include fatigue, exertional dyspnoea, syncope, chest pain, palpitations,cough, heinoptysis and leg edema. Death usually occurs few hours to several days after delivery and related to sudden death or progressive light ventricular failure. The exact cause of death is not clear but light ventricular ischemia and failure caused by increase in pulmonary resistance after delivery, cardiac arrhythmias and pulmonary embolism are possible mechanisms. High incidence of prematuiity of fetus, fetal growth retardation and fetal loss are associated with PPH.Woinen with PPH are advised against pregnancy. If pregnancy occurs, early termination is advised. Incidence of premature delivery is common and should be anticipated. Where PPH is not diagnosed until late in pregnancy an elective delivery is preferred.
Management of Pregnancy and Delivery
There is increased iisk of thl~omboembolism diring pregnancy and anticoagulants are found to be beneficial in PPH, anticoagulants are recommended throughout pregnarlcy or atleast during third trimester and delivery. Many have recommended vaginal delivery under epidural anesthesia. Pulmonaiy vasoconstriction is a prominent feature and hence vasodilators are to be used including oxygen administration, nitric oxide,epoprostenol and iloprost in short term and calcium antagonists in the long term.Nitric oxide has been used in the pre and post delive~y management of PPH in pregnancy. Epoprostenol is a naturally occu~ring prostaglandin and a potent vasodilator. It affects vascular remodeling and inhibits platelet aggregation. Iloprost is a synlhetic analogue of epoprostenol with improved metabolic and chemical stability,which decreases pulmonary arterial pressure and pullnonary vascular resistance,increases cardiac output and has minimal effect on systemic arterial pressure.Successful maternnl and fetal outcome with epoprostenol therapy during pregnancy,caesarian section, and post parlum, in a patient with PPH has been reported. However,greater mortality has been reported from caesarian section and not with vaginal delivery.
The other drug [hat is useful is sildenafi'l, which is a phosphodiesterase type-5 inhibitor- a promising drug in treating pulmonaly hypertension. Similarly endothelin receptor blocker - bosentan is also used to treat pulmonary hypertension. The data on their use in pregnancy is not available at present.
Eisenmenger's Syndrome
Eisenmengers syndrome is a term coined by Paul Wood and is defined as pulmonary vascular obstructive disease that develops as a consequence of a large pre-existing left-to-right shunt such that pulmonary artery pressure approaches systemic levels andthe direction of flow becomes bi-directional or right-to-left. The congenital defects include Atiial Septal Defect (ASD), Ventricular Septal Defect (VSD) and Patent Ductus Arteriosus (PDA) and complex defects like atrio-ventricular canal defects,truncus arteriosus, aorto-pulmonary window and univentricular heart.
In pregnancy, Eisenmetlger's syndrome carries high risk of maternal morbidity and 'mortality of approximately 40 per cent. Mortality usually occurs within first few days or weeks after delivery preceded by clinical and henlodynamic deterioration. Diffuse fibrinoid necrosis of pulmonary arterioles and puln~onauy embolism has been reported. Eisenmenger's syndrotlle is also associated with poor fetal out come with fetal loss, prematurity, fetal growth retardation and perinatal death.
Management: Patients with Eisenmenger's syndromes should be advised against pregnancy because of high risk. Early abortion is advised to patients who are already pregnant, Management of patients who coine late or who decide to continue pregnancy, include close follow-up to detect early deterioration. Anticoagulation is indicated in the third trimester to prevent thromboembolic complications and continued for a few weeks after delivery.Patients with Eisenmenger's syndrome need hospitalization for close monitoring since premature delivery is common, admissioil is advised if there is my sign of uteiine activity. Spontaneous labor is preferred to induction. Monitoring of blood pressure,electrocardiogran~, and blood gas are essential during labor. Most patients may tolerate vaginal delivery, however, illtempt should be made to shorten the second stage of labor by use of forceps or vacuuill extraction. In some patients planned caesarian section is better than emergency caesarian section and hence proper assessment is needed. Inhalation of nitric oxide has been used successfully to reduce pulmonary artery prcssure apd improve oxygen saturation during labor and early peurperium.The use bS sildenafil and bosentan in pregnancy for treatment of pulmonary hypertension is not available at present.
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