Epidemiology and Risk Factors

Secondary causes of pulmonary hypertension include chronic lung disease (COPD and chronic bronchitis), cardiac disease (congenital defects, mitral stenosis, left atrial myxoma), autoimmune or inflammatory conditions such as scleroderma and SLE (Paolini et al., 2004), and granulomatous disease such as sarcoidosis. Certain drugs (fenfluramine) can also cause the condition, as can chronic liver disease with portal hypertension. Some patients experience pulmonary hypertension as a complication of arterial clotting or chronic damage from single or multiple episodes of PE.

Primary pulmonary hypertension is diagnosed when there is no obvious cause of the condition, and there is a familial form of the disease as well. Persistent pulmonary hypertension of the newborn occurs in 1.9 neonates per 1000 live births and results from shunting through a patent foramen

Table 18-5 Diagnostic Tests to Exclude or Confirm Diagnosis of Pulmonary Embolism (PE)

Pretest Probability Based on Objective Clinical Decision Rules

Exclude Diagnosis

(PE <5%)

Confirm Diagnosis (PE >85%)

Low clinical probability (10%)

Negative D-dimer (quantitative or semiquantitative) Negative spiral CT scan Negative MRA Low-probability V/Q scan

Positive pulmonary angiogram (no other test is adequate to confirm positive diagnosis of PE in a patient with low prior probability)

Moderate clinical probability (35%)

Quantitative D-dimer<500^g/L (by ELISA method) Normal or near-normal lung scan Negative spiral CT scan in combination with negative venous Doppler ultrasound of leg veins

Positive spiral CT scan

High-probability

V/Q scan Positive MRA Positive venous Doppler ultrasound of leg veins

High clinical probability (70%)

Negative pulmonary angiogram (no other test is adequate to exclude or rule out diagnosis of PE in a patient with a high prior probability)

Positive spiral CT scan

High-probability

V/Q scan Positive MRA Positive echocardiogram ultrasound

CT, Computed tomography; ELISA, enzyme-linked immunosorbent assay; MRA, magnetic resonance angiography; V/Q, ventilation/perfusion ratio.

ovale and ductus arteriosus, with or without pulmonary hypoplasia (Greenough and Khetriwal, 2005).

Blood Pressure Health

Blood Pressure Health

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