Fontan circulation
Updates to Study Attributes
MRA of the chest showsperformed one year prior illustrates Fontan circulation.
1. The superior vena cava is connected to the right pulmonary artery (right-sided cavopulmonary anastomosis).
2. The right-sided cavopulmonary anastomosis (SVC to RPA) allows a passive venous return to the pulmonary arteries. PassiveThere is preferential venous return to the left pulmonary artery (red arrow) is greater due to venous admixture from the extraatrial conduit (blue arrows).
3. The extraatrial conduit connects the IVC to both the right and left pulmonary arteries.
4. The extraatrial conduit allows flow from the IVC to both pulmonary arteries without the mechanical help of the right ventricle (bypassing the right ventricle). There is venous admixture to both the RPA and LPA (blue arrows).
5. A left pulmonary artery stent is noted.
Terms:- IVC conduit: Inferior vena cava conduit (synonyms include external cardiac conduit or extraatrial conduit)- SVC: superior vena cava- LPA: left pulmonary artery- RPA: right pulmonary artery
Updates to Case Attributes
Key Teaching Points:
- Fontan circulation may mimick a pulmonary embolism on a perfusion scan.
- Due to passive venous return to the pulmonary circulation, pedal injection during perfusion scan may reveal normal perfusion to both lungs.
Patient with a history of tricuspid atresia type IA status post right-sided cavopulmonary anastomosis, extracardiac Fontan, and left pulmonary artery stent placement during childhood.
The initial VQ scan performed with a right upper extremity IV line demonstrates a complete lack of perfusion to the left lung and normal ventilation imaging. Unilateral flow to the right pulmonary artery may be seen, as in this case, mimicking a pulmonary embolism on perfusion scan.
Repeat perfusion images the same day following pedal injection shows homogeneous perfusion to both lungs.
Case prepared with the help of Dr Suzanne Parets and Dr Samuel Valle.
-<p>Patient with a history of <a href="/articles/tricuspid-atresia">tricuspid atresia</a> type IA status post right-sided cavopulmonary anastomosis, extracardiac <a href="/articles/fontan-procedure">Fontan</a>, and left pulmonary artery stent placement. </p><p>The initial <a href="/articles/vq-scan-2">VQ scan</a> performed with a right upper extremity IV line demonstrates a complete lack of perfusion to the left lung and normal ventilation imaging. Unilateral flow to the right <a href="/articles/pulmonary-trunk">pulmonary artery</a> may be seen, as in this case, mimicking a pulmonary embolism on perfusion scan.</p><p>Repeat perfusion images the same day following pedal injection shows homogeneous perfusion to both lungs.</p><p>Case prepared with the help of Dr Suzanne Parets and Dr Samuel Valle.</p>- +<p>Key Teaching Points:</p><ul>
- +<li>Fontan circulation may mimick a pulmonary embolism on a perfusion scan.</li>
- +<li>Due to passive venous return to the pulmonary circulation, pedal injection during perfusion scan may reveal normal perfusion to both lungs.</li>
- +</ul><p>Patient with a history of <a href="/articles/tricuspid-atresia">tricuspid atresia</a> type IA status post right-sided cavopulmonary anastomosis, extracardiac <a href="/articles/fontan-procedure">Fontan</a>, and left pulmonary artery stent placement during childhood. </p><p>The initial <a href="/articles/vq-scan-2">VQ scan</a> performed with a right upper extremity IV line demonstrates a complete lack of perfusion to the left lung and normal ventilation imaging. Unilateral flow to the right <a href="/articles/pulmonary-trunk">pulmonary artery</a> may be seen, as in this case, mimicking a <a title="Pulmonary embolism" href="/articles/pulmonary-embolism">pulmonary embolism</a> on perfusion scan.</p><p>Repeat perfusion images the same day following pedal injection shows homogeneous perfusion to both lungs.</p><p>Case prepared with the help of Dr Suzanne Parets and Dr Samuel Valle.</p>