Successful thrombolysis after pulmonary embolectomy for persistent massive postoperative pulmonary embolism

Pulmonary vasodilation in acute pulmonary embolism - a systematic review

Acute pulmonary embolism is the third most common cause of cardiovascular death. Pulmonary embolism increases right ventricular afterload, which causes right ventricular failure, circulatory collapse and death. Most treatments focus on removal of the mechanical obstruction caused by the embolism, but pulmonary vasoconstriction is a significant contributor to the increased right ventricular afterload and is often left untreated. Pulmonary thromboembolism causes mechanical obstruction of the pulmonary vasculature coupled with a complex interaction between humoral factors from the activated platelets, endothelial effects, reflexes and hypoxia to cause pulmonary vasoconstriction that worsens right ventricular afterload. Vasoconstrictors include serotonin, thromboxane, prostaglandins and endothelins, counterbalanced by vasodilators such as nitric oxide and prostacyclins. Exogenous administration of pulmonary vasodilators in acute pulmonary embolism seems attractive but all come with a risk of systemic vasodilation or worsening of pulmonary ventilation-perfusion mismatch. In animal models of acute pulmonary embolism, modulators of the nitric oxide-cyclic guanosine monophosphate-protein kinase G pathway, endothelin pathway and prostaglandin pathway have been investigated. But only a small number of clinical case reports and prospective clinical trials exist. The aim of this review is to give an overview of the causes of pulmonary embolism-induced pulmonary vasoconstriction and of experimental and human investigations of pulmonary vasodilation in acute pulmonary embolism.

Postoperative Acute Pulmonary Embolism Following Pulmonary Resections

Postoperative acute pulmonary embolism after pulmonary resections is highly fatal complication. Many literatures have documented cancer to be the highest risk factor for acute pulmonary embolism after pulmonary resections. Early diagnosis of acute pulmonary embolism is highly recommended and computed tomographic pulmonary angiography is the gold standard in diagnosis of acute pulmonary embolism. Anticoagulants and thrombolytic therapy have shown a great success in treatment of acute pulmonary embolism. Surgical therapies (embolectomy and inferior vena cava filter replacement) proved to be lifesaving but many literatures favored medical therapy as the first choice. Prophylaxis pre and post operation is highly recommended, because there were statistical significant results in different studies which supported the use of prophylaxis in prevention of acute pulmonary embolism. Having reviewed satisfactory number of literatures, it is suggested that thoroughly preoperative assessment of patient conditions, determining their risk factors complicating to pulmonary embolism and the use of appropriate prophylaxis measures are the key options to the successful minimization or eradication of acute pulmonary embolism after lung resections.

Low-dose urokinase in massive pulmonary embolism when standard thrombolysis is contraindicated

When acute massive pulmonary embolism is life threatening, thrombolysis could be a therapeutic option. However, lysis may be contraindicated once the risk of bleeding is high. We report on two patients who have massive pulmonary emboli complicated by severe hypotension, justifying thrombolytic treatment. Nevertheless, recent surgery in the first patient and a fresh hemorrhagic duodenal ulcer in the second patient precluded thrombolytic treatment at the usual dosage. Therefore, prolonged lysis with low-dose urokinase (1,000 units/kg/h) was initiated. After a few hours, the patients became hemodynamically stable and inotrope/vasopressor doses could be reduced and stopped. No major bleeding was observed. Consequently, prolonged thrombolysis with low-dose urokinase could be an alternative approach to therapy in patients with massive pulmonary emboli when recommended thrombolytic dosages are contraindicated.

Update in the prevention and treatment of deep vein thrombosis and pulmonary embolism

PURPOSE OF REVIEW

Thromboembolic events have a major impact on outcome of surgical and medical patients. This review is focused on standards and recent advances in antithrombotic strategies for prevention and therapy of venous thromboembolism and pulmonary embolism.

RECENT FINDINGS

Alert programs improve prophylactic strategies to prevent venous thromboembolism. Evidenced-based guidelines are available on antithrombotic and thrombolytic therapy outweighing the benefits, risks, burdens and costs. Selective factor Xa and direct thrombin inhibitors are at least as effective as low-molecular-weight heparin in prevention of venous thromboembolism and treatment of pulmonary embolism, but have fewer side effects and will not need routine monitoring. In high-risk orthopaedic patients but not in general surgery patients fondaparinux is superior to low-molecular-weight heparin in the prevention of thromboembolic disease. Ximelagatran, the first oral direct thrombin inhibitor, is as effective and well tolerated as warfarin. Long-term treatment is uncertain, however, because of elevation in alanine transaminase levels. In high-risk patients with contraindication for anticoagulation, retrievable vena cava filters may be an option to prevent pulmonary embolism. Permanent cava filters do not improve long-term survival and are associated with relevant side effects. Thrombolytics should be reserved for deep venous thrombosis complicated by limb gangrene and for life threatening pulmonary embolism.

SUMMARY

There is currently sufficient information based on guidelines available on preventive and therapeutic strategies for venous thromboembolism and pulmonary embolism. Antithrombotics are the therapeutic backbone. In high-risk orthopedic surgery and venous thromboembolism the new antithrombotics fondaparinux, idraparinux and ximelagatran are superior to standard treatment. Temporary caval filters may be a therapeutic option in high-risk patients with contraindication for antithrombotics.

Fehler und Gefahren der perioperativen Lysetherapie

Until recently, perioperative thrombolysis has always been thought to be a contraindication, because of the risk of bleeding complications. However, many case reports now show that thrombolytic drugs can be successfully used in the perioperative period. Possible indications for perioperative thrombolysis are massive pulmonary embolism and cardiopulmonary resuscitation which are also important causes of cardiac arrest. Thrombolysis can be the decisive therapeutical option, e.g. when normal cardiopulmonary resuscitation measures are not successful. Nevertheless, even against the background of many positive case reports the indication for perioperative thrombolysis should be a case-specific decision as the frequency of complications depends on the surgical intervention and must be weighed against the possible benefits of early thrombolysis. For perioperative thrombolysis there are no data available showing a beneficial effect of one particular therapeutic regimen. In the literature it is suggested that thrombolysis should be performed as quickly as possible, because the risk of bleeding complications depends more on the duration of thrombolysis than on the dosage or the thrombolytic drug itself.