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Oct 22, 2012

Approach Pulmonary to hypertension (PH) (Diagnostic algorithm )


Pulmonary hypertension is to be suspected in patients with exertional dyspnoea, syncope, angina, and/or progressive limitation of exercise capacity. Once PH  is suspected  it’s  further work up is to confirm PH presence and search for its underlying aetiology. Pulmonary hypertension is grouped into 6 groups and 1st group is subdivided into two subgroups
1.     Group 1 pulmonary arterial hypertension (PAH)
2.     Group1’ veno-occlusive diseases (PVOD)
3.     Group 2 left heart disease
4.     Group 3 hypoxic lung disease
5.     Group 4 chronic thrombo-embolic disease (CTEPH)
6.     Group 5 multifactorial causes
Diagnostic algorithm begins with first ruling out more common causes group 2 (left heart disease) and group 3 (hypoxic lung disease) than looking for possibility of group 4 (CTEPH) lastly for group 1(PAH) and group 5
Work up of PH begins with noninvasive approach clinical history, symptoms, signs, ECG, chest radiograph, transthoracic echocardiogram, and pulmonary function tests, including nocturnal oximetry if needed.
First is to look for group 2 and group 3 with above mentioned tests and HRCT and ruling out group 2 and group 3. If above mentioned test do not confirm group 2 and group 3 or severity of PH is out of proportion than further work for group 4 (CTEPH) and group 1’ (PVOD) is done with help of ventilation perfusion scans.
If ventilation perfusion scans shows multiple segmental defects than pulmonary angiography (CT pulmonary angiography, RHC, and selective pulmonary angiography) is done to confirm CTEPH (group 4) or PVOD.
If ventilation perfusion scan is normal or shows only subsegmental ‘patchy’ perfusion defects, than tentative diagnosis of group 1 (PAH) is considered, if mean pulmonary pressure is more than 25mmhg and pulmonary wedge pressure is less than 15mmhg.
Further workup in is for specific diagnosis of individual diseases with help of haematology, biochemistry, immunology, serology, and ultrasonography.
Open thoracic biopsy is not done now a days because high morbidity and low yield. See figure for further workup
Diagnostic algorithm of  Pulmonary Hypertension

Group 1 PAH
PAH Group1 is diagnosis of exclusion following conditions are associated with PAH so one has suspect PAH if they are associated
·        Family history of PAH
·        Connective tissue diseases
·        HIV infection
·        Portal hypertension
·        Haemolytic anaemia
·        History of intake of drugs and toxins known to induce PAH