a)  Surgery

Incision along the fourth or fifth rib is made to approach the pulmonary artery. Dissection is started from the interlobar fissure to expose the segmental arteries. Taping is performed to control back flow of blood from peripheral vessels. Dissec- tion must be performed carefully so as not to injure the pul- monary parenchyma. After administration of heparin, either the right or left main pulmonary artery is clamped without cardiopulmonary bypass to monitor changes over time in pul- monary arterial pressure for about 5 minutes. After confirm-ing that pulmonary arterial pressure does not exceed systemic blood pressure, an incision is made into the affected lobe artery to initiate thromboendarterectomy. The dissecting plane is determined as in the median sternotomy technique. The target organized thrombus and the intima are held and pulled along the direction to each segmental artery without cutting off the thrombus and the intima. Following removal of the thrombus and the intima, the peripheral taping is removed to confirm back flow of blood. The incision over the lobe artery is closed by suturing or using an autologous pericardial patch.

b)  Results of Surgery by Masuda et al

Since 1986, Masuda et al have performed PEA by lateral tho- racotomy in 16 patients. In all patients, a right lateral tho- racotomy incision was used to access the pulmonary arteries. No patients exhibited serious arrhythmia or right heart failure. No patients required emergency cardiopulmonary bypass for the treatment of hypoxemia. Two patients underwent throm- boendarterectomy by left lateral thoracotomy as a second- stage procedure in a two-staged operation. Two patients (12.5%) died of surgical complications, due to postoperative pneumonia and postoperative pulmonary edema in one case each. The patients who survived surgery exhibited prompt im- provement in mean pulmonary arterial pressure, cardiac index, and pulmonary vascular resistance, and gradual improve- ment in PaO2 over time, resulting in significant improvement 6 months after surgery. Three patients died 4,220, 1,891, and 1,173 days after surgery, due to sudden death in 2 patients and heart failure in 1 patient. Relationships were suspected to exist between these late-phase deaths and CTEPH.

c)  Summary

Median sternotomy, which enables PEA in both right and left pulmonary arteries in one stage, is used as the standard procedure for treatment of CTEPH, and has yielded favor- able results, particularly in patients with central type of CTEPH.The lateral thoracotomy technique should be considered only for patients with predominantly unilateral disease with peripheral pulmonary lesions.

[Levels of Recommendations]

1. PEA by lateral thoracotomy: Class IIb

Source "Guidelines for the Diagnosis, Treatment and Prevention of Pulmonary Thromboembolism and Deep Vein Thrombosis (JCS 2009)"

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