The incidence of activated protein C resistance among patients with deep vein thrombosis and healthy subjects in Osaka

Clinical characteristics of acute pulmonary thromboembolism in Japan: results of a multicenter registry in the Japanese Society of Pulmonary Embolism Research

BACKGROUND

Although the incidence of acute pulmonary thromboembolism (APTE) has been increasing in Japan, patient characteristics, management strategies, and outcome have not yet been assessed in large series.

HYPOTHESIS

The present study was designed to investigate the current status of APTE in Japan.

METHODS

Of a total of 533 registry patients with pulmonary thromboembolism, 309 with APTE were analyzed with respect to clinical symptoms and signs, predisposing factors, diagnostic procedures, estimation of deep venous thrombosis, treatment, and clinical course.

RESULTS

Main risk factors were recent major surgery, cancer, prolonged immobilization, and obesity; only a few patients had coagulopathy and 36% were in cardiogenic shock at presentation. The majority of registry patients underwent lung scans or pulmonary angiography; 30% were diagnosed only by lung scanning. Venous ultrasonography was used in only 34 patients, while 188 patients underwent at least one diagnostic procedure for deep venous thrombosis. Thrombolysis was more frequently performed in patients with cardiogenic shock, and only a few patients received thromboembolectomy. In-hospital mortality rate was 14%. In patients with cardiogenic shock, the mortality rate was reduced by thrombolysis. The predictors of in-hospital mortality were male gender, cardiogenic shock, cancer, and prolonged immobilization.

CONCLUSIONS

The patients in this registry had almost the same findings as those in Western patients, except for some points that had the possibility of demonstrating a difference between Westerners and Japanese in the development of APTE. These results can prove especially helpful in planning prospective, randomized trials that will clarify the impact of widely used treatment modalities on the outcome of patients with APTE.

Detection of a common mutation in factor V gene responsible for resistance to activate protein C causing predisposition to thrombosis

Hereditary predisposition to thrombosis due to activated protein C resistance (APCR) has been attributed to a missense mutation in the factor V gene at nucleotide 1691 (G to A), causing replacement of arginine at codon 506 with glutamine. Using an RFLP-PCR assay to detect this mutation, we measured a prevalence of 3.3% in healthy Caucasians and 1.25% in healthy African-Americans. In addition, we evaluated a total of 90 consecutive specimens submitted to the coagulation laboratory at the Medical College of Virginia for the presence of this mutation. We compared our results for 78 of these specimens with the values measured by a modified partial thromboplastin assay, the COATEST. Twelve of the 90 samples could not be tested using the COATEST because the patients were undergoing anticoagulant therapy. One of the latter 12 specimens was positive by the RFLP-PCR test. Using the genetic test as the definitive assay and the cutoff value established for distinguishing between normal and abnormal results by the COATEST, the COATEST had a sensitivity of 50% and specificity of 93% for the detection of factor V mutation. Analysis of the 90 samples stratified by ethnic groups revealed a frequency of mutation of 13.3% for Caucasians and 6.88% for African-Americans, although with the present sample size, the difference was not statistically significant. Although the COATEST is technically simpler to perform than the genetic test for diagnosing the presence of the factor V mutation, its use for this purpose is limited due to low sensitivity. Thus where this disorder is clinically suspected, submission of the specimen directly for genetic testing by RFLP-PCR or equivalent assay should be considered.

Relationship Between Activated Protein C Resistance and Central Venous Device-Related Complications

We studied the relationship between activated protein C (APC) resistance and the central venous devices (CVD)-related complications in 61 cancer patients (44 females `and 17 males, median age 50 years, 71 CVD) from November 1994 to November 1995. Two patients (3.3%) had APC resistance, i.e., APC ratio < 2. Twelve episodes of bactercmia, 8 site infections, 31 cases of CVD dysfunction requiring urokinase (UK), and 3 CVD-retated thromboses were noted. With Cox's proportional hazard models, low APC ratios and high d-dimer levels were significantly associated with CVD-related bacteremia (p = 0.0207 and 0.0210). Such an association was not observed with site infection and CVD dysfunction. The incidence of thrombosis was too low to be analyzed. However, one patient with APC resistance developed subclavian vein thrombosis, leading to eventual removal of the catheter. The prevalence of APC resistance in cancer patients and its association with bacteremia are discussed. Key Words : Activated protein C resistance—Central venous catheters—Bacteremia— Catheter site infection—Thrombosis.