Chromic cor pulmonale

8/7/2019 Chromic cor pulmonale

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СHRONIC COR PULMONALE



Introduction

The term cor pulmonale was introduced in 1931 by Dr. Paul D.White. In 1963, The World Health Organization expert

committee proposed a pathologic definition of cor pulmonaleas "hypertrophy of the right ventricle resulting from diseasesaffecting the function and/or structure of the lungs, except when these pulmonary alterations are the result of diseasesthat primarily affect the left side of the heart, as in congenital

heart diseases." In 1970, Behnke and colleagues replaced theconcept of hypertrophy with "an alteration in the structure andfunction of the right ventricle." This definition thus included avariety of disorders ranging from a mild abnormality of theright ventricle to overt right heart failure. The current definition of chronic cor pulmonale is right ventricular

hypertrophy, dilation, or both as a result of pulmonary hypertension caused by pulmonary disorders involving the lung parenchyma, impaired pulmonary bellowsfunction, or altered ventilatory drive.



Right ventricular dilation or hypertrophy in

chronic cor pulmonale is a direct

compensatory effect of chronic pulmonaryvasoconstriction and subsequent pulmonary

artery hypertension that leads to increased

right ventricular work and stress. When the

right ventricle can no longer compensate

through dilation or hypertrophy, right

ventricular failure occurs.

A new diagnostic classification of pulmonaryhypertension was developed by a group of

experts in 1998





2. Pulmonary venous hypertension

2.1 Left sided atrial or ventricular heart

disease

2.2 Left sided valvar heart disease

2.3 Extrinsic compression of central

pulmonary veins

(a) Fibrosing mediastinitis

(b) Adenopathy/tumours

2.4 Pulmonary veno-occlusive disease

2.5 Other



3. Pulmonary hypertension associated withdisorders of the respiratory system and/or

hypoxaemia3.1 Chronic obstructive pulmonary disease

3.2 Interstitial lung disease

3.3 Sleep disordered breathing

3.4 Alveolar hypoventilation disorders

3.5 Chronic exposure to high altitude

3.6 Neonatal lung disease

3.7 Alveolar capillary dysplasia

3.8 Other



4. Pulmonary hypertension caused by

chronic thrombotic and/or embolic

disease4.1 Thromboembolic obstruction of proximal

pulmonary arteries

4.2 Obstruction of distal pulmonary arteries(a) Pulmonary embolism (thrombus,

tumour, ova and/or parasites, foreign

material)(b) In situ thrombosis

(c) Sickle cell disease



5. Pulmonary hypertension caused by

disorders directly affecting the pulmonary

vasculature5.1 Inflammatory

(a) Schistosomiasis

(b) Sarcoidosis

(c) Other

5.2 Pulmonary capillary haemangiomatosis



In our opinion cor pulmonale corresponds to

the third part of this classification (pulmonaryhypertension associated with disorders of the

respiratory system and/or hypoxaemia) and

must be differentiated from pulmonary

venous hypertension (part 2), and also from

primary pulmonary hypertension (part 1) and

from thromboembolic pulmonary

hypertension (part 4).



Aetiology

There are three major groups of diseases:

1. those characterised by a limitation to airflow.Chronic obstructive pulmonary disease (COPD) andother causes of chronic bronchial obstruction;

2. those characterised by a restriction of pulmonaryvolumes from extrinsic or parenchymatous origin(restrictive lung diseases);

3. those where the relatively well preservedmechanical properties of the lungs and chest wallcontrast with pronounced gas exchange

abnormalities which are partially explained by poor ventilatory drive (respiratory insufficiency of "central"origin).



Diseases of the respiratory system associated with pulmonary hypertension (except primarypulmonary hypertension, pulmonary thromboembolic disease, and diseases of the pulmonaryvascular bed)

Obstructive lung diseases

COPD (chronic obstructive bronchitis, emphysema and their association)

Asthma (with irreversible airway obstruction)Cystic fibrosis

Bronchiectasis

Bronchiolitis obliterans

Restrictive lung diseases

Neuromuscular diseases: amyotrophic lateral sclerosis, myopathy, bilateral diaphragmatic paralysis,etc

Kyphoscoliosis

ThoracoplastySequelae of pulmonary tuberculosis

Sarcoidosis

Pneumoconiosis

Drug related lung diseases

Extrinsic allergic alveolitis

Connective tissue diseases

Idiopathic interstitial pulmonary fibrosis

Interstitial pulmonary fibrosis of known origin

Respiratory insufficiency of "central" origin

Central alveolar hypoventilation

Obesity–hypoventilation syndrome (formerly "Pickwickian syndrome")

Sleep apnoea syndrome



Chronic obstructive pulmonary disease is the major

cause of chronic respiratory insufficiency and cor

pulmonale, and it probably accounts for 80–90% of

the cases. Chronic obstructive pulmonary disease

includes chronic obstructive bronchitis and

emphysema, which are often associated. Among the

restrictive lung diseases kyphoscoliosis, idiopathic

pulmonary fibrosis, and pneumoconiosis are the

main causes of cor pulmonale. Among the

aetiologies of respiratory insufficiency of "central"

origin the obesity–hypoventilation syndrome

(formerly "Pickwickian syndrome") is a relativelyfrequent cause of cor pulmonale.



Mechanisms of cor pulmonale

As stated above pulmonary hypertension is the necessary conditionof cor pulmonale. Accordingly, the mechanisms of cor pulmonale

are first those of pulmonary hypertension. In chronic respiratorydiseases pulmonary hypertension results from increasedpulmonary vascular resistance (PVR).

The factors leading to an increased pulmonary vascular resistancein chronic respiratory disease are numerous but alveolar hypoxiais by far the most predominant, at least in сhronic obstructivepulmonary disease, kyphoscoliosis, and the obesity–hypoventilation syndrome. Two distinct mechanisms of action of alveolar hypoxia must be considered: acute hypoxia causespulmonary vasoconstriction, and chronic longstanding hypoxiainduces structural changes in the pulmonary vascular system

such as hypertrophy of the muscular media of the smallpulmonary arteries, muscularisation of pulmonary arterioles, andintimal fibrosis. It is pulmonary vascular remodelling.



Furthermore, other functional factors must be

considered, namely hypercapnic acidosis andhyperviscosity caused by polycythaemia, but

their role seems small when compared to that

of alveolar hypoxia. In pulmonary fibrosis the

increase of pulmonary vascular resistance is

caused by anatomical factors: loss of

pulmonary vascular bed or compression of

arterioles and capillaries by the fibrosingprocess.



Pulmonary hypertension increases the work of the

right ventricle, which leads more or less rapidly to

right ventricular enlargement (associatinghypertrophy and dilatation), which can result in

ventricular dysfunction (systolic, diastolic). Later,

right heart failure (RHF) characterised by the

presence of peripheral oedema can be observed, at

least in some respiratory patients. The interval

between the onset of pulmonary hypertension and

the appearance of right heart failure is not known

and may vary from one patient to another. There is

a relation between the severity of pulmonary

hypertension and the development of right heart

failure.



Clinical signs

History

Clinical manifestations of cor pulmonale generally are nonspecific.

The symptoms may be subtle, especially in early stages of thedisease, and mistakenly may be attributed to the underlyingpulmonary pathology. The patient may complain of fatigue,exertional dyspnea and syncope with exertion—symptomsreflecting a relative inability to increase cardiac output duringexercise with a subsequent drop in the systemic arterial

pressure. Exertional chest pain also can occur and may be dueto pulmonary artery stretching and right ventricular ischemia.Other symptoms mainly related to pulmonary artery hypertensioninclude cough and, sometimes, hemoptysis. In advancedstages, passive hepatic congestion secondary to severe rightventricular failure may lead to anorexia, right upper quadrantabdominal discomfort, and jaundice. Swelling of the legs alsocan occur, and syncope is a late and ominous occurrence.



Physical examThe most evident physical findings in cor pulmonale reflect the

underlying lung disease, with an increase in chest diameter, laboredrespiratory efforts with retractions of the chest wall, hyperresonance

to percussion, diminished breath sounds, wheezing, distant heartsounds, and, rarely, cyanosis. Physical findings characteristic of pulmonary hypertension, right ventricular hypertrophy (RVH) andright ventricular failure also may be present.

Early signs characteristic of pulmonary artery hypertension includesplitting of the second heart sound with accentuation of the

pulmonic component. Right ventricular hypertrophy is characterized by a left parasternalor subxiphoid heave. A prominent a wave in the jugular venouspulse associated with a right-sided fourth heart sound also can bepresent and reflects the increase in the filling pressure of the rightventricle.

Right ventricular failure leads to systemic venous congestion, whichis manifested as distended neck veins, occasionally associated withpulsatile liver, and peripheral edema. Pleural effusions and ascitesare uncommon, even in severe cor pulmonale.



Laboratory studies

Laboratory investigations are directed toward

defining the potential underlying etiologies aswell as evaluating complications of cor

pulmonale. In specific instances, appropriate

lab studies may include the following:

hematocrit for polycythemia, serum alpha1-

antitrypsin if deficiency is suspected, and

antinuclear antibody level for collagen

vascular disease. Hypercoagulability statescan be evaluated by serum levels of proteins

S and C, antithrombin and other tests



Imaging Studies

Chest roentgenogram: The chest x-ray in patients with

chronic cor pulmonale may show enlargement of the centralpulmonary arteries with oligemic peripheral lung fields.

Pulmonary hypertension should be suspected when the right

descending pulmonary artery is larger than 16 mm in diameter

and the left pulmonary artery is larger than 18 mm in

diameter. Right ventricular enlargement leads to an increase of the

transverse diameter of the heart shadow to the right on the

posteroanterior view and filling of the retrosternal air space

on the lateral view.

These findings have reduced sensitivity in the presence of

kyphoscoliosis or hyperinflated lungs.



Echocardiography: Two-dimensional echocardiographyusually demonstrates signs of chronic right ventricular pressure overload.

As this overload progresses, increased thickness of the rightventricular wall with paradoxical motion of the interventricular septum during systole occurs.

At an advanced stage, right ventricular dilatation occurs, andthe septum shows abnormal diastolic flattening. In extremecases, the septum actually may bulge into the left ventricular

cavity during diastole. Doppler echocardiography is used now to estimate pulmonary

arterial pressure, taking advantage of the functional tricuspidinsufficiency that usually is present in pulmonaryhypertension. Doppler echocardiography is considered themost reliable noninvasive technique to estimate pulmonaryartery pressure. The efficacy of Doppler echocardiographymay be limited by the ability to identify an adequate tricuspidregurgitant jet, which may be further enhanced by using salinecontrast.



In selected cases, ventilation-perfusion lung

scanning, pulmonary angiography, and

chest computer tomography scanning

may be indicated to determine underlyingetiology.



Other Tests:

Electrocardiography. Electrocardiogram abnormalities in cor pulmonale reflect the presence of right ventricular hypertrophy or

strain. Electrocardiogram criteria for cor pulmonale such as right axis

deviation have high specificity but low sensitivity, particularly inpatients with biventricular hypertrophy.

P-pulmonale pattern due to right atrial enlargement and rightbundle branch conduction abnormalities may be present.

Patients with severe underlying obstructive lung disease mayhave low-voltage QRS on their electrocardiogram, reflecting theinterposition of hyperexpanded lung between the heart and chestwall.

Additionally, many rhythm disturbances may be present inchronic cor pulmonale.

In selected cases, pulmonary function testing may beindicated to determine underlying etiology.



Procedures: Cardiac catheterization: Right-heart catheterization

is considered the most precise method for diagnosis

and quantification of pulmonary hypertension. It isindicated when echocardiography cannot assess theseverity a tricuspid regurgitant jet, thus excluding anassessment of pulmonary hypertension. Right-heartcatheterization occasionally is important for

differentiating cor pulmonale from occult leftventricular dysfunction, especially when thepresentation is confusing. Another indication may befor evaluation of the potential reversibility of pulmonary arterial hypertension with vasodilator

therapy. Lung biopsy occasionally may be indicated todetermine underlying etiology.



Differential diagnosis

Other problems to be considered:

Congestive (biventricular) heart

failure Pulmonic valve stenosis

Primary pulmonary hypertension



Congestive heart failure

Congestive heart failure should be considered first of all.

Congestive heart failure is the pathophysiologic state in which theheart, via an abnormality of cardiac function fails to pump blood

at a rate commensurate with the requirements of themetabolizing tissues. Heart failure always causes circulatory failure.

Heart failure may be caused by myocardial failure. Two thirds caused bycoronary artery disease. The second most common cause is dilatedcardiomyopathy. Other causes include chronic hypertension, valvular

heart disease, hypertrophic cardiomyopathy, and restrictivecardiomyopathy.

Typical symptoms include fatigue, dyspnea, orthopnea, paroxysmalnocturnal dyspnea and chronic cough.

Physical exam demonstrates hepatojugular reflux, rales, and peripheraledema. However, these are not present in all those with congestiveheart failure.

The baseline studies are chest x-ray and electrocardiogram. Anechocardiogram may be indicated to evaluate left ventricular and rightventricular ejection fractions, movement of chamber walls and valves,and chamber sizes. In systolic dysfunction, ejection fraction isdecreased.



Pulmonic valve stenosis

Narrowing of the pulmonic valve orifice due to congenital pulmonic valve abnormalities, most frequently a domed

valve, occasionally bicuspid, with restricted opening.Pulmonic valve stenosis of varying degree constitutes about10% of congenital heart disease.

In newborns, pulmonic valve stenosis with severe obstruction toright ventricular outflow may present as an emergency with

right-to-left atrial shunting. It requires immediate diagnosis: byelectrocardiogram showing diminished right ventricular forces(when the right ventricular is hypoplastic, which is usuallysevere) or right ventricular hypertrophy; by x-ray showingdecreased pulmonary blood flow; by echocardiography,showing a severely narrowed valve with restricted movement;and possibly by catheterization and angiography to evaluatepotential right ventricular function.



In older children, cyanosis is not present, although

poor peripheral color may result from prolongedcirculation and a wide arteriovenous oxygen

difference. An ejection murmur, usually with a

prominent ejection click, is found at the upper left

sternal border with an increasingly late peak asobstruction increases. Electrocardiogram shows

increasingly severe right ventricular hypertrophy. X-

ray shows a normal heart size and a prominent main

pulmonary artery segment with increasingly severeobstruction. The pulmonary vascular markings are

narrow.



Primary pulmonary hypertension

A very uncommon obliterative disease of unknown causeinvolving medium and small pulmonary arteries resulting

in right ventricular failure or fatal syncope 2 to 5 yr after detection.

Women are affected twice as often as men. The median age atdiagnosis is 35 yr; younger patients have a worse prognosis.Intimal hyperplasia and consequent narrowing of the vessellumen are always present. Areas of medial hypertrophy andhyperplasia, irreversible plexiform lesions, and necrotizingarteritis (plexogenic arteriopathy) occur in more advancedcases.

Progressive exertional dyspnea occurs in > 95% of cases.Precordial pain and syncope on exertion are less common.Raynaud's phenomenon and arthralgias occur in manypatients, often years before the apparent onset of primarypulmonary hypertension.



Diagnosis is suspected on the basis of clinicalmanifestations, but all known causes of cor

pulmonale must be excluded. Physicalexamination shows, to a variable extent, themanifestations of cor pulmonale.

Echocardiography, ventilation/perfusion

scanning, pulmonary function testing, andcardiac catheterization are usually necessaryto exclude other causes of pulmonaryhypertension. Pulmonary angiography should

be undertaken if ventilation/perfusion scansshow unmatched segmental or larger perfusion defects.



Treatment Oxygen therapy, diuretics, vasodilators, digitalis, theophylline,

and anticoagulation therapy are all different modalities used inthe long-term management of chronic cor pulmonale.

Oxygen therapy is of great importance in patients with cor pulmonale particularly when administered on a continuous basis.Oxygen therapy relieves hypoxemic pulmonary vasoconstriction,which then improves cardiac output, lessens sympatheticvasoconstriction, alleviates tissue hypoxemia, and improves renalperfusion.

Diuretics are used in the management of chronic cor pulmonale,particularly when the right ventricular filling volume is markedlyelevated. Diuretics may result in improvement of the function of boththe right and left ventricles; however, diuretics may producehemodynamic adverse effects if they are not used cautiously.Excessive volume depletion can lead to decline in cardiac output.Another potential complication of diuresis is the production of a

hypokalemic metabolic alkalosis, which diminishes the effectivenessof carbon dioxide stimulation on the respiratory centers and lessensventilatory drive. Therefore, diuretics, while recommended in themanagement of chronic cor pulmonale, needs to be used with greatcaution.



Vasodilator drugs have been advocated in the long-termmanagement of chronic cor pulmonale with modest results.Calcium channel blockers, particularly oral sustained-releasenifedipine and diltiazem, can lower pulmonary pressures,although they appear more effective in primary rather thansecondary pulmonary hypertension. Right heart catheterizationhas been recommended during initial administration of vasodilators to objectively assess the efficacy and detect thepossible adverse hemodynamic consequences of vasodilators.

The use of cardiac glycosides, such as digitalis, in patientswith cor pulmonale has been controversial, and the beneficialeffect of these drugs is not as evident as in the setting of leftheart failure. Nevertheless, studies have confirmed a modesteffect of digitalis on the failing right ventricle in patients withchronic cor pulmonale. It must be used cautiously, however, andshould not be used during the acute phases of respiratoryinsufficiency when large fluctuations in levels of hypoxia andacidosis may occur. Patients with hypoxemia or acidosis are atincreased risk of developing arrhythmias due to digitalis.



Theophylline has been reported to reduce pulmonaryvascular resistance and pulmonary arterial pressures inpatients with chronic cor pulmonale. Theophylline has a

weak inotropic effect and thus may improve right and leftventricular ejection.

Anticoagulation with warfarin is recommended inpatients at high risk for thromboembolism. The beneficialrole of anticoagulation in improving the symptoms and

mortality in patients with primary pulmonary arterialhypertension clearly was demonstrated in a variety of clinical trials. The evidence of benefit, however, has notbeen established in patients with secondary pulmonaryarterial hypertension. Therefore, anticoagulation therapymay be used in patients with cor pulmonale secondary tothromboembolic phenomena and with underlying primarypulmonary arterial hypertension.



Further inpatient care

Appropriate treatment is directed both at the

underlying etiology and at correction of hypoxia when present.

Further outpatient care

Patients with cor pulmonale generally requireclose attention in the outpatient setting.

Regular assessment of oxygen needs and

pulmonary function are appropriate.

Many patients benefit from a formal program

of pulmonary



Complications

Complications of cor pulmonale include syncope,hypoxia, pedal edema, passive hepatic congestion,

and death.Prognosis The prognosis of cor pulmonale is variable

depending upon underlying pathology.

Patients with cor pulmonale due to chronicobstructive pulmonary disease have a high 2-year mortality.

Patient education:

Patient education regarding the importance of

adherence to medical therapy is vital becauseappropriate treatment of both hypoxia andunderlying medical illness can improve mortality andmorbidity.

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Chromic cor pulmonale