Pulmonary Embolism

The remaining 94 lung scan results and the corre­sponding plasma DNA determinations are listed in Table ЗА. Only results from the initial plasma sample were used for these comparisons. The proportion of patients having DNA detected in their plasma pro­gressively increased as the lung scans went from normal (0 percent) to high probability (73 percent). This was highly significant (p<0.001 by x2)- Two of the 22 patients with a high probability lung scan had normal pulmonary angiograms and negative plasma DNA tests. Thus, 80 percent of patients with high probability lung scans and a final diagnosis of pulmo­nary embolism had detectable plasma DNA. Nine of 12 patients who had an indeterminate/intermediate probability lung scan had pulmonary angiograms. Two of these nine studies were positive and led to a final diagnosis of pulmonary embolism. Three of the 46 patients who had low probability lung scans had pulmonary angiograms performed and all were nor­mal.

Table 3B provides further comparisons of plasma DNA and pulmonary angiography results. All three patients who had an abnormal angiogram for pulmo­nary embolism had detectable plasma DNA. The DNA titers for these patients were at least 1:4 initially and subsequently increased to 1:8 or 1:32. In contrast, only four of 13 patients who had a normal angiogram for pulmonary embolism were found to have detecta­ble plasma DNA. These four patients with false- positive plasma DNA findings had either a low prob­ability or indeterminate lung scan followed by a pulmonary angiogram. Two patients had the angio­gram performed on the same day as the lung scan. The other two patients had their angiograms within 48 hours of the lung scan. Two patients had DNA titers of 1:4, one of these decreased or became undetectable in 48 hours, one patients plasma DNA was positive undiluted only, and the fourth patient did not have sufficient plasma to titer. All four patients were dyspneic and three had an acute onset of pleuritic chest pain. The final clinical diagnoses for these patients were congestive heart failure and possible pneumonia, “pleuritis” in a patient with rheumatoid arthritis, nonspecific chest pain in a patient with pancreatitis and disseminated intravascular coagula­tion, and Legionella pneumonia. Among the nine patients with normal angiograms and negative plasma DNA testing, six were studied within 48 hours of their symptoms. Final diagnoses for the three with delayed studies were nonspecific pneumonia, congestive heart failure, and idiopathic pericarditis/pleuritis. All pa­tients with normal pulmonary angiograms had selec­tive pulmonary artery studies. discount drugs canda

Table 3—Correlation of Measurable Plasma DNA and Lung Scan (A) and Angiogram (B) Results

A. Correlation of
Measurable Plasma DNA and Lung Scan Results

No. of

No. with

Percent

Lung Scan Result

Lung Scans

DNA

with DNA

Normal

14

0

0

Low probability

46

20

43

Intermediate
probability

12

6

50

High probability

22

16

73

Total

94

43

45

X2
analysis p<0.001

B. Correlation of
Measurable Plasma DNA and Angiogram Results

Pulmonary

No. of

No. with

Percent

Angiogram Result

Angiograms

DNA

with DNA

Positive

3

3

100

Negative

13

4

31

Total

16

7

44

Fishers extact
test p = 0.06

Figure 1 compares the pulmonary embolism diag­nosis in the diagnosis established group with the plasma DNA results. For this selected group of 49 patients who clearly had or did not have pulmonary embolism, the sensitivity of measurable plasma DNA for pulmonary embolism was 82 percent and the specificity was 85 percent.

Ficuaı 1. Sensitivity and specificity

FIGURE 1. Sensitivity and specificity of plasma DNA.

In 89 episodes of suspected pulmonary embolism, more than one plasma sample was collected. Of the 18 patients with circulating plasma DNA and a final diagnosis of pulmonary embolism, 15 had more than one plasma sample obtained; 14 of the 15 had detect­able DNA for more than 48 hours; and eight had DNA persisting for greater than four days. One patient had samples from days 1, 6, 11, and 12 after symptom onset, and all of these were positive for DNA. Another patient had detectable DNA in plasma up to 11 days and two patients had circulating DNA for ten days. cialis soft tablets