Pulmonary Angiography - Uses, Procedure, Limitations, and Recent Advancements

What Is a Pulmonary Angiography?

An angiogram is a diagnostic procedure that uses X-rays and contrast material to analyze the blood vessels (usually the arteries and veins) in the body. An angiogram is considered the gold standard to diagnose blocked or narrow vessels. An angiogram, when performed to observe the blood vessels of the lungs, is known as a pulmonary angiogram. It helps to check if a blood clot is obstructing the vessels and also to gauge the pressure within the blood vessels.

What Are the Uses of Pulmonary Angiography?

• Pulmonary angiography can be used both as a diagnostic and therapeutic tool as it can be used to detect and treat a blood clot.

• Pulmonary angiography is most commonly indicated in conditions like pulmonary embolism, aneurysm, and pulmonary hypertension. and arteriovenous malformation

• It is used to detect vessel wall stenosis.

• Patients complaining of persistent chest pain.

• To detect the presence of a foreign body.

• Congenital developmental defects in the blood vessels connecting the heart and lungs.

• Patients with a history of deep vein thrombosis or other clotting disorders.

• Pulmonary angiography can also be used as a channel to direct cancer drugs to the lungs.

How Should Patients Prepare for a Pulmonary Angiogram?

• Pulmonary angiography is done under sedation; hence, patients are required to abstain from eating and drinking for six to eight hours before the procedure.

• Patients can wear clothes that are loose and comfortable and remove all jewelry, accessories, and other metallic objects.

• Patients should report to the doctor if they have any history of allergy to contrast material, medicines, latex, or anesthesia.

• Ladies who think they could be pregnant should also inform the doctor before the procedure.

• Doctors may prescribe blood tests to determine clotting time and other preoperative assays.

• The patient should keep the doctor informed if they are on Aspirin or other blood-thinning medications.

How Is a Pulmonary Angiogram Carried Out?

• Pulmonary angiography is usually conducted as an outpatient procedure.

• The patient has to wear a hospital gown before starting the procedure.

• The patient will be required to have an empty bladder before the procedure.

• The patient will be taken to the examination room and made to lie on their back on the examination table.

• An I.V. (intravenous) lines would be started on the arm or hand to give mild sedatives.

• The vitals such as pulse, breathing, and blood pressure would be monitored. An ECG machine would also be connected to monitor the patient’s heart.

• The preferred site for catheter insertion is the arm or groin. The site would be shaved or trimmed of hairs and cleaned using an antiseptic solution.

• The site would be anesthetized using a local anesthetic. The patient might experience a burning sensation.

• A tiny incision is made in the vein through which a catheter is inserted. The catheter, with the help of a fluoroscope, is carefully advanced up through the vein to the right chamber of the heart and into the pulmonary artery, which guides to the lungs.

• The contrast material will be injected via the catheter, and X-ray images will be taken.

• The course and the movement of the dye will help to evaluate the presence of any blockages within the blood vessel.

• Patients could feel nausea or headache for a brief time when the contrast is injected. They can also get a salty or metallic sensation in their mouth.

• Once the images are taken, the catheter is removed.

• Pressure and dressing are applied over the incision site for the bleeding to stop.

What Are the Instructions After the Procedure?

• Patients should lie flat on their back with legs and hands stretched for two hours after the procedure.

• Analgesics would be given to relieve any pain.

• Patients are advised to drink plenty of water to expel the contrast material from the body.

• Refrain from smoking and alcohol.

• Patients should avoid any form of physical strain for the next few days.

• Patients should monitor the incision site for any unusual changes.

When to Seek Medical Advice?

• A sudden rise in temperature.

• Uncontrolled bleeding from the site of the incision.

• Swelling, redness, discharge from the incision site.

• Pain, weakness, or tingling sensation in any of the extremities.

What Are the Benefits and Risks of This Procedure?

Benefits:

• Minimally invasive.

• Can detect arterial, venous, and structural abnormalities.

Risks:

• Patients can develop abnormal heart rhythms, which will be managed by the doctor immediately.

• Infection and bleeding.

• Allergic reaction to the contrast material used.

• Catheter insertion can rarely cause damage to the blood vessels or nerves.

• The possibility of a pulmonary embolism as an existing clot may get dislodged.

• Hematoma formation.

• Risk of radiation exposure.

• Heart attack, stroke, renal failure, respiratory failure.

What Are the Limitations of This Procedure?

• Pulmonary angiography is not advised in pregnant women and lactating mothers.

• Caution needs to be exercised while using this procedure in renal disease patients and patients on dialysis.

• Known history of allergy to contrast material.

What Are the Recent Advancements in Pulmonary Angiography?

Conventional pulmonary angiography is almost completely replaced by computed tomography pulmonary angiography (CTPA). CTPA is now considered the standard diagnostic test used to detect any blockages in blood vessels or a pulmonary embolism. A conventional pulmonary angiography may be used only in situations where a CT may be contraindicated or may prove non-diagnostic.

The indications for using a CTPA are similar to that of pulmonary angiography. The procedure is similar except that instead of a conventional X-ray, a CT scanner would be used to image the patient.

How Is CTPA Finer Than a Conventional Pulmonary Angiography?

• CTPA has increased sensitivity and specificity than its conventional counterpart.

• CTPA provides images with high precision.

• A conventional pulmonary angiography uses a single X-ray source and detector, resulting in a two-dimensional image, whereas a CTPA uses many X-ray sources and scanners, thus enabling a three-dimensional image with increased resolution.

• A CTPA has the added benefit of imaging other structures along with the lung simultaneously.

What Is the Role of CT Pulmonary Angiography in COVID-19?

Pulmonary embolism is one of the most common complications encountered in COVID-19 patients. It has had serious debilitating effects on the prognostic outcome. Though a chest CT has proved vital in diagnosing COVID pneumonia and other thoracic complications, further enhanced assessment is needed in patients with respiratory failure and other compromised conditions. A CTPA is indicated in COVID-19 patients with:

• Severe respiratory failure.

• High demand for oxygen despite controlled lung disease.

• Dilation of the right chamber of the heart.

• Compromised hemodynamic state.

• When coagulation parameters are abnormal.

CTPA is not only useful to detect pulmonary embolism, but is also found useful to evaluate deep vein thrombosis (DVT), right ventricular dysfunction, vasculopathy, and defects in the lung parenchyma in COVID-19 patients.

Conclusion:

Pulmonary angiography is a safe and minimally invasive technique to evaluate the blood flow to the lungs. CTPA has proved even more efficient than conventional pulmonary angiograms in detecting blocked vessels and embolisms. The advantage of this procedure is both diagnostic and therapeutic, making it ideal and benefiting the patient.