Diagnostic Tests & Procedures
The start of symptoms in pulmonary hypertension can be very subtle and often patients and their physicians may not recognize that they have a serious medical condition. Pulmonary hypertension can thus be difficult to diagnose. In addition, symptoms are nonspecific and may include, but are not limited to, shortness of breath, fatigue, chest discomfort, syncope, and palpitations.
The initial evaluation of each patient begins with review of any previous medical evaluations and a comprehensive history and physical examination at Stanford. After the initial consultation a Stanford faculty physician will contact the referring physician and together with the patient and their family will review diagnostic and therapeutic options. Generally, several diagnostic tests may be required to diagnose pulmonary vascular disease and help ascertain its cause. The most common tests, all of which are performed at Stanford and Packard Hospitals in state-of-the art facilities, include the following:
A simple chest x-ray may help ascertain certain important basic facts about the anatomy of the heart and lungs and can be used to diagnose certain lung conditions associated with pulmonary vascular disease.
An EKG is a measurement of the electrical activity of the heart and abnormalities in an EKG may show certain types of stress on the heart.
Comprehensive Blood Tests
Blood testing is used to evaluate for possible underlying diseases such as, underlying liver disease, collagen-vascular disease (mixed connective tissue disease, lupus, scleroderma, rheumatoid arthritis), thyroid disorders, etc.
An echocardiogram is a non-invasive test that uses sound waves to show in detail the anatomy of the heart and to estimate flows and pressures in the chambers of the heart. It can be used to diagnose congenital heart defects and can helpful in planning surgery in patients for whom surgery is the recommended treatment.
Pulmonary Function Tests (PFT)
Pulmonary function tests involve an assessment of lung function through measurements of the airflow in the lungs and the overall lung volumes. While breathing through a mouth piece patients are asked to perform certain breathing maneuvers that are measured by a computer. Often as part of the PFTs a blood sample from an artery in the wrist (an arterial blood gas, or ABG) is obtained so that the oxygen content of the blood can be measured precisely. An exercise test may also be performed to assess and quantify a patient's exercise capacity.
Ventilation-Perfusion Scanning (V/Q scan)
A V/Q scan shows the pattern of air flow (the V part) and the pattern of blood flow (the Q part) in the lungs. It can be useful in determining whether or not a patient has large blood clots in their lungs.
Computerized Axial Tomography (CT Scan)
A CT scan of the chest can detect lung disease that may be missed on a chest x-ray and is an important tool in providing detailed anatomy of the heart, lungs and surrounding blood vessels. CT angiography using new ultrafast CT scans can also be used to diagnose blood clots in the lungs.
Cardiac catheterization is the gold standard for diagnosing pulmonary hypertension, assessing its severity and its effects on the heart. A cardiac catheterization involves threading a plastic catheter through a large vein in the neck, leg or arm and into the heart where direct measurement of pressures in the right side of the heart and the pulmonary arteries can be made. Congenital heart defects may be identified during a cardiac cath and sometimes transcatheter interventions may replace the need for more invasive treatments such as surgery. Testing with drugs that dilate the blood vessels in the heart (vasodilator testing) can be safely done during a cardiac catheterization and results of this test may guide the choice of therapy in each patient.
Polysomnography (Sleep Study)
The test consists of recording a number of physiologic parameters on the patient while they sleep. A polysomnograph is a machine that converts electrical impulses in the body to a graphical representation which can help determine what's happening as we sleep. Many different activities are monitored by the polysomnograph during a sleep study. These include brain waves (EEG), eye movements (EOG), muscle activity (EMG), heartbeat (EKG), blood oxygen levels and respiration. Each of these activities is represented by graphical tracings on a polysomnogram.
Six-minute Walk Test
This is a test that requires you to walk for six minutes while the distance you cover and your level of breathlessness are recorded. The test can be performed with or without supplemental oxygen.
Cardiopulmonary Exercise Test
Test Measures endurance and the ability of the patient's lungs to compensate during physical activity. Your heart and oxygen levels are monitored while you walk on a treadmill or ride an exercise bike.