Observer variation in the interpretation of ventilation-perfusion lung scintigraphy.

The diagnosis of pulmonary embolism (PE) remains one of the most difficult in clinical medicine, and the diagnostic value of lung scintigraphy has been questioned. To evaluate the observer variation in the interpretation of ventilation-perfusion lung scanning in the diagnosis of PE, 87 lung scintigrams from consecutive patients with phlebography-proven deep venous thrombosis and without clinical signs of PE were randomly mixed with 50 reference lung scintigrams from patients with PE symptoms. The scintigrams were reevaluated blind by two experienced clinical physiologists. Each observer evaluated each lung scintigram twice and recorded whether the lung scan was normal or abnormal. If it was abnormal, the location and number of segment defects were registered. The intraobserver agreement, including number and location of segments, ranged from 0.77 to 0.85 and for the diagnosis of PE from 0.88 to 0.92 with a kappa of 0.80-0.84. The values for the interobserver agreement for the diagnosis of PE were 0.73-0.80 with a kappa of 0.56-0.67. It is concluded that in the interpretation of ventilation-perfusion lung scintigraphy the use of a simple scheme-deciding whether there is segmental ventilation-perfusion mismatch or not-has a good reproducibility with a high kappa for inter- and intraobserver variation and can serve as a simple routine method for diagnosing PE.

Acetylsalicylic acid 100 mg and 1000 mg daily in acute myocardial infarction suspects: a placebo-controlled trial.

Of 1078 patients admitted to the coronary care unit with acute chest pain, 293 who had possible acute myocardial infarction and symptoms of median 4 h duration were randomized to treatment with acetylsalicylic acid (ASA) 100 mg daily, 1000 mg daily or placebo for 3 months. During hospitalization, the combined incidence of cardiac death and non-fatal myocardial infarction on-treatment (withdrawals not included) was significantly lower (P less than 0.02) in the 100 mg group (7.1%) than in both the 1000 mg group (20.8%) and the placebo group (19.7%). During later time periods of treatment and at all time periods analysed according to the intention-to-treat principle (withdrawals included), data suggested the same trend, but differences were not statistically significant. Collagen-induced platelet aggregation and serum thromboxane B2 were reduced to the same degree in the two ASA groups and were normal in the placebo group. The data suggest that low-dose ASA could be cheap and safe as first-aid therapy in myocardial infarction suspects.

Prevention of postoperative deep venous thrombosis. Low-dose heparin versus graded pressure stockings.

In a prospective, controlled clinical study prevention of postoperative deep venous thrombosis by low-dose heparin (Heparin Leo 5 000 I.U. subcutaneously twice daily) was compared with graded compression stockings (TED stockings, Kendall Co.). One hundred and twelve patients, admitted during a period of one year for elective major surgery, were allocated to one of the two treatment groups. In order to detect deep venous thrombosis the 99mTc-plasmin test was performed before the operative procedure and again 5 days later. Ninety-seven patients completed the study (45 patients in the heparin group and 52 patients in the stocking group). Venous thromboembolism was detected in 4 patients (8.9%) in the heparin group and in 3 patients (5.8%) in the stocking group (p greater than 0.05). In 6 patients the plasmin test was positive and one patient in the heparin group died following pulmonary embolism. It is concluded that graded compression stockings can be used as an alternative to low-dose heparin for prophylaxis against deep venous thrombosis in elective general surgery.