Diagnosis Management Of Inpatients With An Elevated Plasm D-dimer:Developing A New Clinical Decision Rule For Pulmonary Embolism

Background: A positive D-dimer test owns a high sensitivity but a relatively poor specificity to diagnose pulmonary embolism(PE),making it difficult for clinicians unskilled in PE diagnosis to determine whether a patient with a positive D-dimer test needs a gold standard exam—CT pulmonary angiography(CTPA).Objectives: We sought to develop a new clinical decision rule based on a positive D-dimer result to pretest for the probability of PE and to guide clinicians in making appropriate decisions regarding CTPA exam.Methods: We conducted a prospective,multicenter,cohort study in 3 hospitals in China.3014 inpatients with positive D-dimer results were included.In derivation group,we built a multivariate logistic regression model and deduced a regression equation by which our score was derived.Finally,we validated the score in an independent cohort.Results: Our score included 9 variables(points): chest pain(1.4),chest tightness(2.3),anhelation(3.6),hemoptysis(3.4),heart rate ?100 beats/min(3.6),blood gas analysis(Table 4)(2.9),electrocardiogram presenting typical S1Q3T3 pattern(4.1),electrocardiogram findings(Table 4)(2.4),and ultrasonic cardiogram findings(Table 4)(3.7).In the derivation sample,the sensitivity was 100%,the specificity was 86.94%,and in the validation sample,the sensitivity was 100%,the specificity was 90.82%.In addition,the observed and predicted proportions of patients undergoing CTPA were 16.82% and 10.76%,respectively,in the derivation group and 18.72% and 11.40%,respectively,in the validation group.Conclusions: The new score can categorize inpatients with a positive D-dimer test as PE-like or PE-unlike,and reduce unnecessary CTPA examinations.