Pulmonary trunk

First level of thoracic vessels Aorta, pulmonary trunk, ductus arteriosus, atria, bronchus, pulmonary vein and arteries, and vena cava (see Note 11). 

The pulmonary trunk arising from the right ventricle is inspected. 

The ductus arteriosus joins the pulmonary trunk to the descending aorta. 

Both ventricular outlets are verified using a fine pointed probe from each ventricular chamber into the respective aortic arch or pulmonary trunk. 

Right Ventricle Pumps blood to the pulmonary artery through the pulmonary valve and pulmonary trunk to the lungs where C02 is exchanged for 02... 

Symptoms of pulmonary hypertension include dyspnea on exertion, chest pain, palpitations, syncope, ascites and lower extremity edema. Anginal symptoms may occur and are thought to be due to increased RV oxygen demand, decreased right coronary artery perfusion due to decreased pressure difference between aorta and RV end diastolic pressure, and rare instances of compression of the left main coronary artery by the dilated pulmonary trunk. Right ventricular hypertrophy (RVH) correlates with EKG findings including RV... 

The pulmonary trunk and pulmonary arteries larger than 500 pm or 1 mm in diameter are designated elastic pulmonary arteries. Their tunica media consists of multiple concentric elastic laminae separated by smooth muscle, collagen and ground substance containing proteoglycan. 

In tissue sections of the porcine pulmonary trunk, endothelial cells were specifically immunola-belled with both the monoclonal and polyclonal antibodies raised against vimentin (Schnittler et al. 1998). A moderate degree of staining intensity was observed in all endothelial cells of the pulmonary trunk. The pulmonary trunk contained a 2- to 2.5-fold higher amount of vimentin than the endocardial endothelium of the right ventricle. Cultured endothelial cells of the porcine pulmonary trunk displayed considerably higher amounts of vimentin than did freshly isolated cells. 

Tao Bolus tracking in the descending aorta, Tpa bolus tracking in the pulmonary trunk ... 

The challenge for spinal artery CTA is to provide sufficient arterial enhancement but to scan before arrival of contrast medium in the venous system. An ROI of the bolus tracking system placed in the ascending aorta might be affected by inflow artifacts of the SVC and may result in a mistimed early scan. Therefore, placement of the ROI in the aortic arch or descending aorta is recommended. In the presence of aortic dissection, caution should be taken that the ROI is not too big or positioned in the false lumen or across the dissection membrane, respectively. In these cases, manual start of the scan should be considered. The Hounsfield unit threshold should be around 100 HU above baseline. Scan start is usually delayed by time for table movement (<3 s), which is usually right above the origin of the vertebral arteries. An additional scan delay of 3 s is recommended for scanners with equal to or more than 16 rows and rotation time equal or less than 0.4 s. Hounsfield unit values of attenuated blood in the thoracic aorta should never be lower than within the pulmonary trunk. 

Figure 8. Surface display of human (62 year old male) left ventricle with apical aneurysm. Scan performed during levo phase of bolus injection of renografin into pulmonary trunk (Sinak et ai, 1984d).

The ascending aorta is dissected from the pulmonary trunk and circumferentially freed. 

If the lungs are also retrieved, a modified heart-explantation technique is used. The left atrial incision is made in the middle, between the atrioventricular groove and the orifice of the left pulmonary veins. This incision is extended clockwise to the orifice of the right pulmonary veins in order to preserve enough left atrial tissue for the later left atrial anastomosis as well as enough tissue for the creation of atrial cuffs for the lung transplantation. In this case the pulmonary trunk is transected immediately in front of the bifurcation into the pulmonary arteries. 

The aorta is then cut through above the aortic valve and this should be done carefully in order not to injure the right pulmonary artery, which lies directly behind the aorta. After that the pulmonary trunk is transected as proximally as possible. 

Next the pulmonary anastomosis is performed with a 4-0 polypropylene running suture. To avoid kinking of the new pulmonary trunk the proper length has to be measured and the vessels are trimmed. Again at the left lateral side of the recipient, pulmonary arterysuturing starts with first completing the back wall and finally the anterior wall. It is important to prevent rotation of the pulmonary artery. 

On the pulmonary side, the Medtronic Melody transcatheter has been successfully implanted in over 1000 patients to date to address right ventricular outflow tract (RVOT)/pulmonary trunk dysfunction. This device has been FDA approved under the Humanitarian Device Exemption (HDE) program, paving the way for implantation in patients in the United States as well. 

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