The preoperative management of patients with massive pulmonary embolism is probably the most critical part, reflecting on the success of the entire procedure. Patient management depends on their clinical status and the level of hemodynamic stability.

In general, this group of patients can be separated into three: Group 1, hemodynamically stable patients; Group 2, hemodynamically unstable patients; Group 3, patients under cardiopulmonary resuscitation (CPR).

Group 1 patients should receive high-dose unfractionated heparin (bolus of 5000 IU, followed by infusion of at least 1000 IU/h) once the diagnosis is made. Following that, maintaining adequate oxygenation and cardiac output before establishing CPB is essential. Endotracheal intubation should be established if hypoxemia is present. If adequate cardiac output cannot be maintained with vasopressors, phosphodiesterase inhibitors may be given. Otherwise, if the clinical situation permits, the usual preparations for establishment of CPB should be made.

Most stable patients undergo chest CT for definite diagnosis. However, if diagnosis of pulmonary embolism has not been made with certainty before the patient is transported to the operating room, TEE should be performed to establish the diagnosis before the chest is opened (Kirklin/Barratt-Boyes Cardiac Surgery: Expert Consult).

In Groups 2 and 3 patients, maintaining adequate oxygenation and cardiac output is of paramount importance. This can be achieved either by endotracheal intubation and external (automatic) chest compression devices or, if available, emergent connection to an extracorporeal membrane oxygenator (ECMO) might be considered. ECMO has proven itself as an excellent tool for stabilizing such patients until their transfer to the operating room. In some instances, ECMO can stabilize patients before a definite diagnosis of massive pulmonary embolism is made, thus allow the performance of CT or echocardiography on ECMO before the final decision to perform surgical embolectomy is made.

Transesophageal echocardiogram is essential in all patients before median sternotomy is undertaken.

A midline sternotomy is performed. If peripheral cannulation has not been established, central cannulation is undertaken, either using a single two-stage venous cannula or by bi-caval cannulation and an aortic cannula. CPB is established and mild hypothermia is instituted. Following, the surgery itself may be performed either on a beating heart or with aortic cross-clamping and cardioplegic infusion or fibrillatory arrest. Some authors advocate avoidance of aortic cross-clamping and cardioplegic arrest. (Leacche et al. 2005) Nevertheless, the literature is equivocal on the matter.

The left atrium and left ventricle may be decompressed with a venting catheter inserted into the right superior pulmonary vein.

The pulmonary trunk is incised longitudinally several centimeters distal to the pulmonary valve. If necessary, the incision can be extended into the left pulmonary artery, and a separate incision can be made in the right pulmonary artery between the superior vena cava and ascending aorta. (Fig. 5) Because of the size and fragile nature of a fresh clot in the main pulmonary arteries, it is extremely important to be able to extract the clot as much as possible without disrupting it. Therefore, in our experience, performing the operation with aortic cross-clamping, ensuring a blood-less surgical field, is the most efficient and safe way for effectively removing the clots. Additionally, various techniques and tools have been utilized for manual extraction of the pulmonary clots. It is essential to use an instrument that allows a wide and gentle grip on the clot. A sponge holder (Fig. 5, 6) or any other surgical tool that provides a wide, firm but gentle grip will assist in pulling the fresh clot without disrupting it (Fig. 7).

After the main clots are removed, further attempts are made for the removal of the smaller and more distal clots. These can be extracted using Fogarty catheters, forceps and suction tube.

If a sterile pediatric bronchoscope is available, the surgeon can use this instrument to locate and remove thrombi in tertiary and quaternary pulmonary vessels. Alternatively, the pleural spaces are entered, and each lung is gently compressed to dislodge small clots into larger vessels and suctioned out.

Depending on preoperative information with regard to thrombi in the right-heart chambers, the right atrial and RV cavities are explored through a right atriotomy to search for and remove residual thrombi.

After removing the thrombus, incisions in the pulmonary arteries are closed with continuous 4–0 polypropylene suture. After completion of rewarming and evacuation of air from the cardiac chambers, CPB is discontinued. Weaning from bypass may be long, depending on the extent and how long the right ventricular was compromised before the operation. Patients after CPR and patients with a modest amount of clot removal are prone to have difficulties in weaning from the heart-lung machine (Kronik et al. 1989).

Typical retrieved surgical specimens: (Fig. 8, 9 and 10).

Postoperative circulatory support is often required, depending on the status of the right ventricle and whether or not it suffered any ischemia. Circulatory support can be achieved with an RV assist device and intra-aortic balloon counter-pulsation or extracorporeal life support, as indicated for patients with persisting severe RV failure at the end of surgical embolectomy. (Lango et al. 2008; Maggio et al. 2007) For patients with substantial distal blood clots in the peripheral pulmonary arteries and persistent hypoxia, ECMO may be the perfect bridge to recovery for a few days while the fresh clots undergo lysis.