[Embolectomy in massive lung embolism].
Pulmonary embolism was first described by Laennec in 1819. After introduction of the Trendelenburg surgical technique, Kirschner, in 1925, performed the first successful embolectomy. In a review of the literature, in 42 patients, survival rate was 45% on use of a modified Trendelenburg method employing cross-clamping of the vena cava. The use of this intervention can still be considered justified if extracorporeal circulation is not available. Establishment of the indication and anatomical fundamentals The indication for surgical embolectomy is considered established in the presence of massive pulmonary arterial obstruction with pending death of the patient. The difficulty lies in identification of the patient with massive pulmonary embolism who will succumb and in defining the extent of pulmonary arterial obstruction which will lead to death. Limitation of the indication to only those patients in shock led to mortality rates up to 93%. Immediate death after pulmonary embolism is not the rule. Of 52 patients with massive pulmonary embolism, 50% survived more than two hours; in those with no preexistent cardiopulmonary disease up to eight hours. Surgical intervention can be considered accordingly. Anatomically, massive pulmonary embolism implies at least 60 to 70% obstruction of the pulmonary arterial bed. In 85 of 100 patients who died of pulmonary embolism, voluminous emboli were found in both pulmonary arteries. In the presence of preexistent cardiopulmonary disease, lesser degrees of obstruction can lead to a critical condition. In consideration of the indication as above, the following comments are considered appropriate: 1. Quantification of the obstruction: Pulmonary angiography remains the most appropriate diagnostic examination. The degree of obstruction can be quantified according to a number of indices. As of 60%-obstruction, surgical intervention can be considered. 2. Justification of embolectomy: The classical indication can be established in 2 to 6% of the patients based on treatment-refractory hypotension. In Table 1, the classical stages of massive pulmonary embolism are shown with the indication for embolectomy being considered as of stage IV but these characteristics are unreliable in everyday practice. If surgery is delayed until vasoactive drugs are no longer effective, an irreversible condition is frequently incurred in spite of operative removal of the obstruction. More favorable results can be achieved when the indication for surgery is based only on the degree of obstruction since, in this case, the condition of shock will not be prolonged and a hemodynamically-stable patient can be subjected to surgery. 3. Thrombolytic treatment