Recent developments in the diagnosis, treatment, and prevention of pulmonary embolism

The diagnosis of pulmonary embolism remains enigmatic. Points to look for are: (1) Ninety percent or more of patients with pulmonary embolism have known predisposing factors. (2) Eighty percent or more complain of dyspnea and exhibit hyperpnea (eg, respiratory rate > 20 breaths per minute). (3) Chest roentgenogram abnormalities occur in more than 80% of patients. (4) Seventy percent to 90% of patients complain of chest pain. (5) Either the pCO2 is low or the alveolar-arterial oxygen gradient is high in more than 95% of cases. (6) Twenty percent of patients have normal pO2. (7) Anxiety is present more often than not, and, if present, is no reason to dismiss the cause as "hyperventilation syndrome." Pulmonary arteriography is the "gold standard" for diagnosis, although the combination of ventilation/perfusion scan and noninvasive leg vein studies may decrease its use. An experimental test, the immunosorbent plasma D-dimer assay, seems a promising future screening tool if its reportedly high sensitivity is confirmed. Transthoracic or esophageal echocardiology, if immediately available, may have a place in assessing patients who present with cardiovascular collapse. Early and adequate heparinization coupled with the use of intravenous heparin protocols should lower future mortality rates. Food and Drug Administration approval of low-molecular-weight heparin and heparinoids may revolutionize the management of routine thromboembolism, as these substances are easier to use and less hazardous. A recent British study showed no advantage to anticoagulation beyond 4 weeks for patients with perioperative thrombophlebitis and no other risk factors. In selected cases, thrombolytic therapy, vena caval filters, and invasive embolectomy have been shown to decrease both short- and long-term mortality.