Autopsy findings indicate that 73% of pulmonary emboli diagnosed at autopsy were not detected clinically.<sup>70 Landefeld C.S., Chren M.M., Myers A. , e al. Diagnostic yield of the autopsy in a university hospital and a community hospital N Engl J Med 1988 ;  318 : 1249  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> The clinical diagnosis of venous thromboembolism is unreliable, and the first manifestation of the disease may be fatal pulmonary embolism. Patients may be totally asymptomatic, or they may have symptoms such as dyspnea, tachypnea, or chest pain, which may be dull and centrally located or pleuritic in nature. Patients often will have hypoxemia, and may initially also have hypocapnia secondary to hyperventilation. Wheezing may occur as a result of the release of emboli-associated inflammatory mediators such as serotonin. Patients may also have nonspecific signs, such as tachycardia or signs of right ventricular strain on ECG or on echocardiogram. The chest radiograph is often normal. At the other end of the spectrum is the patient who presents with sudden-onset cardiovascular collapse and pulseless electrical activity.

It is well known that surgery predisposes patients to venous thromboembolism. Less appreciated is the fact that they are at risk, not only in the immediate postoperative period, but even as late as 1 month postoperatively.<sup>11 Bergqvist D., Lindblad B. A 30-year survey of pulmonary embolism verified at autopsy: An analysis of 1274 surgical patients Br J Surg 1985 ;  72 : 105

Cliccare qui per andare alla sezione Riferimenti, 55 Huber O., Bounameaux H., Borst F. , e al. Postoperative pulmonary embolism after hospital discharge: An underestimated risk Arch Surg 1992 ;  127 : 310

Cliccare qui per andare alla sezione Riferimenti</sup> Deep vein thrombosis (DVT) and pulmonary embolism represent two aspects of the same disease process. Treatment and duration of treatment are usually the same in both instances.

Because diagnosis and treatment both confer significant risks to the patient, there has been an ongoing search to determine the optimal strategy for confirming, or excluding the diagnosis. Several factors have to be considered in the diagnostic work-up, such as the role of history and physical examination, and how it influences the final diagnosis. Laboratory data and other diagnostic tests should be evaluated for their sensitivity and specificity, cost-effectiveness, availability, expertise required in their interpretation, ease of performing, and patient comfort.

Advances have occurred in the field of anticoagulation with the introduction of low molecular weight heparins (LMWHs). Anticoagulation carries significant risks. The low therapeutic index of oral anticoagulants requires careful long-term monitoring, which in itself poses problems, and results in significant costs and inconvenience to patients. The role of inferior vena caval filters and surgical intervention also have associated significant costs and risks.

The identification and stratification of patients at risk for venous thromboembolism is of paramount importance in order to institute effective prophylaxis and treatment. Most patients who die from pulmonary embolism do so within 30 minutes of the acute event—too soon for anticoagulation to be effective.<sup>27 Donaldson G.A., Williams C., Scannel J.G. , e al. A reappraisal of the application of the Trendelenburg operation to massive fatal embolism: Report of successful pulmonary-artery thrombectomy using a cardiopulmonary bypass N Engl J Med 1963 ;  268 : 171

Cliccare qui per andare alla sezione Riferimenti</sup> Despite numerous studies attesting to the efficacy and safety of prophylaxis, it is still underused.<sup>16 Bratzler D.W., Raskob G.E., Murray C.K. , e al. Underuse of venous thromboembolism prophylaxis for general surgery patients: Physician practices in the community hospital setting Arch Intern Med 1998 ;  158 : 1909  [cross-ref]

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