Pulmonary Angiography Technique 

Updated: Sep 13, 2015
Author: Amanda M Wiant, MD; Chief Editor: Caroline R Taylor, MD 

Overview

Background

The pulmonary vasculature may be evaluated with various invasive and noninvasive methods. Historically, catheter-directed pulmonary angiography has been used most commonly for the diagnosis of suspected pulmonary embolism (PE). Over the past two decades, however, catheter angiography has become almost entirely supplanted by CT angiography (CTA), which is now the accepted standard of care for diagnosis of suspected PE, in part owing to its superior sensitivity and specificity.[1, 2, 3, 4, 5] Other noninvasive methods, such as MRI/A and V/Q scans, are also used to evaluate the anatomy and hemodynamics of the pulmonary vasculature.[6]

Currently, the main clinical utility of conventional pulmonary angiography is for therapeutic intervention and, in selected cases, preoperative evaluation of the pulmonary arteries.

Selected examples of abnormalities identified with pulmonary angiography are shown below.

Selective left pulmonary angiogram shows abrupt ta Selective left pulmonary angiogram shows abrupt tapering of the segmental pulmonary arteries (arrow) with heterogeneous opacification of the parenchyma. Mean pulmonary arterial pressure was 40 mmHg. These findings are consistent with chronic pulmonary thromboembolism.
(A) Selective right pulmonary arteriogram shows la (A) Selective right pulmonary arteriogram shows large filling defects in the right upper (short arrow) and right lower (long arrow) lobe pulmonary arteries. In another patient, selective right pulmonary arteriogram (B) shows a filling defect in the right upper lobe pulmonary artery (arrow), which correlates with a large segmental filling defect (black arrows) on V/Q scan (C).
PA chest radiograph shows right subclavian port wi PA chest radiograph shows right subclavian port with a fractured fragment in the right lower lung (arrow). B: Fluoroscopic intraprocedure image with a snare (long arrow) tethering the catheter fragment (short arrow).
(A) Selective interlobar right pulmonary arteriogr (A) Selective interlobar right pulmonary arteriogram shows large AVM in the lateral right lower lobe (arrow). (B) On late arterial phase imaging, there is early opacification of an inferior right pulmonary vein (arrow heads) draining the AVM. (C) Postembolization arteriogram shows occlusion (arrow) of the supplying artery to the AVM.
(A) Pulmonary arteriogram shows irregular contour (A) Pulmonary arteriogram shows irregular contour to the main (arrow) pulmonary artery with abrupt cutoff in the expected region of the left pulmonary artery (arrowhead) and attenuation of the proximal right pulmonary artery (white arrow). (B) Perfusion image from a VQ scan shows no activity in the left lung (oval), correlating with complete occlusion of the left pulmonary artery seen on angiography.
(A) Anteroposterior chest radiograph shows increas (A) Anteroposterior chest radiograph shows increased lung volumes and marked radiolucency of the right upper lung in a patient with severe emphysema. (B) Right pulmonary arteriogram shows thin, severely tapered segmental arteries in the right upper lobe with increased space between vessel. Contrast this appearance with chronic pulmonary embolism (above), in which the space between arteries is normal.

Indications

Catheter pulmonary angiography is indicated for diagnosis and treatment of PE in certain circumstances. Pulmonary angiography can be used in a diagnostic dilemma, although CTA is the clinically preferred method. In chronic PE, pulmonary angiography is used for surgical planning prior to pulmonary endarterectomy.[7] As for treatment indications, thrombectomy and catheter-directed thrombolysis are used for acute massive or submassive PE.[8, 9, 10, 11, 12] Indications include hemodynamic instability, right heart strain/failure, severe hypoxemia, free-floating right ventricular (RV) thrombus, patent foramen ovale (PFO), and failed systemic thrombolysis.[13, 14]

Pulmonary angiography is indicated in the treatment of pulmonary arteriovenous malformations or fistulas. Endovascular coiling is indicated when the feeding artery is greater than 3 mm in diameter.[15]

Treatment of iatrogenic or postinfectious pseudoaneurysm is an indication, particularly in the presence of significant hemoptysis.[16, 17]

Pulmonary angiography is indicated as part of a complete embolization for severe cavitary or inflammatory lung lesions.

It is indicated in the evaluation of the pulmonary arteries for tumor encasement.

Catheter pulmonary angiography is also used in the retrieval of foreign objects, such as an embolized catheter fragments or even inferior vena cava (IVC) filters.[18]

Contraindications

According to American College of Radiology (ACR) and Society of Interventional Radiology (SIR) guidelines,[19] there are no absolute contraindications to catheter pulmonary angiography. As with any interventional procedure, evaluation of the patient’s clinical and renal status, any allergies to intravenous contrast, and anticipated hemodynamic or cardiac issues should be carefully weighed.

Complication Prevention

If the catheter does not easily advance into the RV, the coronary sinus may have been entered inadvertently. Gently inject contrast material under fluoroscopy to check for this if the catheter does not advance.

Be cognizant of left bundle branch block (LBBB) before starting the procedure. To avoid complete heart block, a transvenous pacemaker or external pacing leads should be in place prior to starting the procedure.

Complications

With the use of modern equipment and nonionic low osmolar contrast agents, complications in conventional pulmonary angiography are rare and usually minor. They include the following:[20]

  • Transient arrhythmia (be aware of preexisting arrhythmia, particularly LBBB)

  • Entry-site hematoma

  • Contrast reaction

  • Respiratory distress

  • Pulmonary edema[21]

  • Rarely, injury to pulmonary artery (PA), cardiac perforation, cardiac arrest

  • Rare case report of stroke in a patient with PFO[22]

 

Periprocedural Care

Pre-Procedure Planning

Before the procedure, the interventionalist should review the following patient information in addition to a complete history and physical examination:

  • Vital signs and hemodynamic parameters

  • Allergies, particularly to intravenous contrast material or other procedural medications such as sedatives

  • Medications, including anticoagulants, antiplatelet agents, and metformin

  • ECG abnormalities: Look specifically for LBBB[23] ; potentially fatal complete heart block is a risk during manipulation of the catheter through the right heart by induction of a right bundle branch block; if LBBB is present, a transvenous pacemaker or external pacing leads should be in place prior to starting the procedure possibly in consultation with the cardiology service

  • Laboratory studies: Blood urea nitrogen/creatinine, coagulation parameters (PT, PTT, INR, platelets), pregnancy test (if appropriate)

  • Imaging: CT scanning (to evaluate anatomic abnormalities and to plan approach), ultrasonography (to check for location of deep venous thrombosis, if present), echocardiography (may show right heart dysfunction in a patient with PE; PFO increases the risk of periprocedural stroke in rare circumstances)

Patient Preparation

The patient is placed on nothing by mouth (NPO) status according to the institution’s requirements for patients undergoing monitored moderate conscious sedation.

Anesthesia

Anesthetize the skin using appropriate anesthetic agent. Conscious sedation may be used depending on the clinical status of the patient.

Be alert for airway issues when giving respiratory depressants. Avoid excessive sedation, since breath-holding during imaging is crucial in obtaining diagnostic-quality imaging.

Positioning

The patient is placed in the supine position on the angiographic table.

Monitoring & Follow-up

Periprocedural observation includes puncture site checks to evaluate for hematoma, in addition to frequent vital sign monitoring for the first 4 hours postprocedure.

 

Technique

Vascular Access

Using ultrasonography, evaluate the common femoral (or, if required, the right internal jugular) vein for patency and compressibility. If there is any thrombus or indwelling catheter, the approach may need to be altered. Clean and drape the site. Anesthetize the skin using appropriate anesthetic agent. Conscious sedation may be utilized depending on the clinical status of the patient. Avoid oversedation since patient cooperation and breath holding are imperative for good quality imaging.

Access the femoral (or right internal jugular) vein using the standard venous puncture protocol. Ultrasonography may be used as an adjunct, if needed. Sheath placement depends on operator preference.

Studies have shown high success rates with ultrasound-directed catheter pulmonary angiography for thrombolysis in massive and submassive pulmonary embolism.[9, 11]

 

Catheter Selection

Numerous articles have described a multitude of techniques for accessing the pulmonary arteries, some using specialized catheters and guidewires.[24, 25, 26, 27, 28]

The Grollman catheter (Cook Medical, Inc., Bloomington, IN), for example, is a preformed pigtail catheter that has a gentle rightward curve with a second 90° leftward curve at the distal aspect of the catheter; its distal tip is in a pigtail configuration (see image below). This shape was designed for access from the right femoral vein and allows for easier maneuvering through the right heart and pulmonary arteries.[29]

Pulmonary angiography catheter. The Grollman cathe Pulmonary angiography catheter. The Grollman catheter has a gentle curve along the distal portion, with a 90 degree bend 3 cm from the pigtail terminus. Permission for use granted by Cook Medical Incorporated, Bloomington, Indiana.

Multiple variations on this design have been produced, such as the St. Charles catheter (Cook Medical, Inc., Bloomington, IN). More standard catheters, such as the Omni-flush (Angiodynamics Inc., Queensbury, NY), may be used along with a malleable hydrophilic wire to shape the catheter. There is also a specialized C-shaped Hunter catheter for a brachiocephalic approach.[26] A Swan-Ganz catheter can also be used to flow directly into the pulmonary arterial circulation by inflating the balloon.

The main principles for catheter and guidewire selection

Use a catheter that has side-holes, such as a pigtail, to decrease the risk of damaging the vasculature

Have some means of creating a 90° or near 90° angle within several centimeters of the distal portion of the catheter to improve maneuverability through the right heart. Use a preformed specialized catheter or gently bend the stiff end (back end) of a guidewire to create an angle in an otherwise straight catheter (make sure the guidewire always stays inside the catheter; otherwise, it will damage the vessel/mediastinal structures.)

Use a soft-tipped or tip-deflecting wire (eg, Reuter tip-deflecting wire, Cook, Inc. Bloomington, IN) and protect the tissues from a regular-tip wire.

Intracardiac and Intrapulmonary Catheter Manipulation

After gaining central venous access, advance a 6-7F catheter into the right atrium under fluoroscopic guidance (see image below). Continuous cardiac monitoring is imperative to assess for arrhythmia as the catheter traverses the heart.

Right femoral vein approach with the St. Charles c Right femoral vein approach with the St. Charles catheter tip in the right atrium. Courtesy of Christopher Friend, MD.

Rotate the catheter such that the pigtail lies facing the tricuspid valve. Advance the catheter tip into the RV. Turn the catheter counterclockwise while advancing the catheter, and the pigtail should approach the main pulmonary artery (see images below).

Tip of catheter in the main pulmonary artery. Tip of catheter in the main pulmonary artery.
Digital subtraction angiography image shows the pi Digital subtraction angiography image shows the pigtail catheter in the main left pulmonary artery.

The left pulmonary artery is the continuation of the main pulmonary artery and is easily accessed by advancing the catheter placed in the main pulmonary artery.

Accessing the right pulmonary artery requires a sharp turn, and using a J-tipped guidewire may assist in accessing this vessel. Alternately, a hydrophilic wire may sometimes be necessary to access the right pulmonary artery (see image below).

Tip of catheter in the right pulmonary artery. A g Tip of catheter in the right pulmonary artery. A guidewire (arrowhead) was used for navigation.

For selective catheterization of segmental pulmonary arteries, a straight-tipped catheter, such as the Berenstein (Angiodynamics, Inc., Queensbury, NY), may be used (see image below).

Selective segmental branch pulmonary arteriogram i Selective segmental branch pulmonary arteriogram is facilitated with use of a Berenstein catheter.

Pressure Measurements

Measuring pressures in the heart and pulmonary arteries may be necessary, especially when evaluating a patient with chronic thromboembolic disease. Typically, pressures in the right atrium, RV, and main pulmonary artery are measured.[30]

Normal pressure values are as follows:

  • Right atrium or central venous pressure, 3-5 mm Hg

  • RV, 20-25 mm Hg

  • Pulmonary artery, 20-25 mm Hg/10-15 mm Hg

  • Pulmonary capillary wedge, 10-15 mm Hg

Image Acquisition

To obtain a diagnostic pulmonary angiogram, have the patient suspend respiration after a full inspiration during the injection of contrast material to minimize motion artifact. For most studies, it is recommended to obtain 3-4 images per second for the first 5 seconds and then 1-2 images per second for the remainder. The following views should be obtained for a complete study:

  • Anteroposterior of each side (see image below)

    Normal right (A) and left (B) pulmonary angiograms Normal right (A) and left (B) pulmonary angiograms showing gradual tapering of the pulmonary arteries, normal caliber vessels, and no filling defects.
  • Posterior oblique projections of the lower lobes (see image below)

    (A) Anteroposterior angiogram of the right pulmona (A) Anteroposterior angiogram of the right pulmonary artery shows no abnormality. (B) On the oblique view, a filling defect is visible posteriorly (arrow).
  • Use magnification to interrogate any specific regions of interest (see image below)

    (A) Left pulmonary angiogram shows faint subsegmen (A) Left pulmonary angiogram shows faint subsegmental filling defect in the lateral basal pulmonary artery that is imaged more clearly (arrow) on the magnified view (B).

To minimize the risk of adverse reactions, low osmolar nonionic contrast should be used. Typical injections rates are listed below. To help determine the rate of injection, evaluate the rate of flow through the selected artery using hand-delivered test injections; if contrast dissipates quickly, a higher rate should be used. Although the authors list injection rates for the main pulmonary artery to be complete, images from such injections are typically of poor quality, and injection here is therefore not advised. Selective right and left lung arteriograms yield better diagnostic images.

For patients with renal failure or other contraindications to iodinated contrast material, CO2 may safely be used as a contrast agent;[31] however, imaging of the distal vasculature may be of poor quality.[32]

Injection rates

Injection rates are as follows:

  • Main pulmonary artery, 25-30 mL/s for 2 seconds

  • Left pulmonary artery or right pulmonary artery, 15-20 mL/s for 2 seconds

  • Lobar or segmental, 5-10 mL/s for 2 seconds

Image Interpretation

When interpreting the images, evaluate for aberrant vessels, such as scimitar vein or anomalous coronary artery, particularly in the pediatric population.[33] Also assess the caliber and contour of vessels. Vessels should be free of filling defects and should taper gradually. Flow dynamics are also assessed. Finally, evaluate the timing of arterial, parenchymal, and pulmonary venous opacification.