Deficient tissue plasminogen activator release and normal tissue plasminogen activator inhibitor in a patient with recurrent deep vein thrombosis

Tissue plasminogen activator plasma levels as a potential diagnostic aid in acute pulmonary embolism

CONTEXT

Pulmonary embolism (PE) is a potentially fatal and frequent complication of deep venous thrombosis, and the most reliable techniques for the diagnosis of PE are not universally available and have other limitations.

OBJECTIVE

To determine the efficacy of 4 different fibrinolysis system parameters, namely, tissue plasminogen activator (tPA), tissue plasminogen activator inhibitor type 1 (PAI-1), plasmin-antiplasmin complexes (PAP), and D-dimer, in the diagnosis of acute PE.

SETTING

A 350-bed university hospital serving an area with 280,000 inhabitants.

PATIENTS

Sixty-six consecutive outpatients with clinically suspected PE. The diagnosis of PE was based on ventilation-perfusion (V/Q) lung scan in combination with clinical assessment, lower limb study, and (when required) pulmonary angiography.

MAIN OUTCOME MEASURES

At the moment of clinical suspicion, a sample of venous blood was obtained to measure levels of tPA, PAI-1, PAP, and D-dimer using an enzyme-linked immunosorbent assay method.

RESULTS

Twenty-seven patients (41%) were classified as PE positive (high clinical probability and V/Q lung scan [n = 12], nondiagnostic V/Q lung scan and high clinical probability [n = 1], inconclusive V/Q lung scan and positive lower limb examination for deep venous thrombosis [n = 11], and positive pulmonary angiography [n = 3]), and 39 patients (59%) were classified PE negative. The sensitivity/negative predictive value for tPA, using a cutoff of 8.5 ng/mL, and PAI-1, using a cutoff of 15 ng/mL, were 100%/100% and 100%/100%, respectively. A tPA level lower than 8.5 ng/mL occurred in 13 (19.7%; all PE negative) of 66 patients with suspected PE, and PAI-1 levels were lower than 15 ng/mL in 9 (13.6%; all PE negative) of 66 patients with suspected PE. The D-dimer, using a cutoff of 500 ng/mL, showed a sensitivity and negative predictive value of 92.6% and 87.5%, respectively.

CONCLUSIONS

Our data indicate that tPA and PAI-1 levels are potentially useful in ruling out PE, although tPA seems to be the better parameter. The sensitivity levels and negative predictive values for the rapid enzyme-linked immunosorbent assay for D-dimer used in this investigation were low compared with previous studies using the same test.

Alcohol consumption and risk of deep venous thrombosis and pulmonary embolism in older persons

OBJECTIVES

To assess whether low to moderate alcohol consumption decreases the risk of deep venous thrombosis and pulmonary embolism.

DESIGN

Prospective cohort study.

SETTING

Three communities of the Established Populations for Epidemiologic Studies of the Elderly.

PARTICIPANTS

A total of 7959 persons aged 68 years or older.

MEASUREMENTS

The incidence of deep venous thrombosis and pulmonary embolism was assessed by surveying hospital discharge diagnoses and deaths from 1985 through 1992. Those participants who estimated they used alcohol less than 1 time, on average, in the past month, less than 1 ounce per day, and 1 ounce or more per day were compared with those who reported no alcohol intake in the past year. Age, gender, race, body mass index, smoking, education, income, disability, cognitive function, arterial pressure, medication use, baseline chronic conditions, number of hospital admissions in past year, and occurrence of disease during follow-up were examined as possible confounders.

RESULTS

During 48,038 person-years of follow-up, 155 events were observed (35 deep venous thromboses and 123 pulmonary emboli). Compared with non-drinkers, after adjusting for potential confounding variables, the relative risks (95% confidence interval) for deep venous thrombosis and pulmonary embolism associated with increasing alcohol consumption levels were 0.7 (0.4-1.1), 0.6 (0.4-0.9), and 0.5 (0.2-1.1), respectively (P for trend = .004). The results were unchanged after stratifying on health status and disability.

CONCLUSIONS

Low to moderate alcohol consumption is associated with a decreased risk of deep venous thrombosis and pulmonary embolism in older persons.

Baseline fibrinolytic state and the risk of future venous thrombosis. A prospective study of endogenous tissue-type plasminogen activator and plasminogen activator inhibitor

BACKGROUND

Although isolated abnormalities of plasminogen activation and inhibition have been reported among selected patients with venous thrombosis, it is unclear whether these deficiencies of fibrinolysis are important risk factors for thromboembolic disease.

METHODS AND RESULTS

To evaluate whether baseline levels of endogenous tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) predict the future occurrence of venous thrombosis, levels of these proteins were measured in prospectively collected plasma samples from 55 participants in the Physicians' Health Study who later developed deep venous thrombosis or pulmonary embolism and from an equal number of age- and smoking-matched control subjects who remained free of vascular disease during a mean follow-up period of 60.2 months. Overall, there were no statistically significant differences between case patients and control subjects in baseline levels of PAI-1 (50.5 versus 59.5 ng/ml, p = 0.26), t-PA (13.4 versus 13.3 ng/ml, p = 0.94), or PAI-1:t-PA ratio (6.84 versus 6.58, p = 0.82). No evidence of a threshold effect or trend was seen when these data were analyzed by increasing quartiles of PAI-1 (p = 0.73), t-PA (p = 0.62), or PAI-1:t-PA ratio (p = 0.93). These results were unchanged after multivariate analysis that simultaneously controlled for other baseline cardiovascular risk factors.

CONCLUSIONS

In contrast to previous uncontrolled case series and smaller retrospective studies, these prospective data provide strong evidence that baseline fibrinolytic state, as measured by t-PA and PAI-1, does not predict the occurrence of future venous thrombosis.