Accuracy of Clinical Assessment in the Diagnosis of Pulmonary Embolism

Abstract

To provide clinical diagnostic criteria for pulmonary embolism (PE), we evaluated 750 consecutive patients with suspected PE who were enrolled in the Prospective Investigative Study of Acute Pulmonary Embolism Diagnosis (PISA-PED). Prior to perfusion lung scanning, patients were examined independently by six pulmonologists according to a standardized diagnostic protocol. Study design required pulmonary angiography in all patients with abnormal scans. Patients are reported as two distinct groups: a first group of 500, whose data were analyzed to derive a clinical diagnostic algorithm for PE, and a second group of 250 in whom the diagnostic algorithm was validated. PE was diagnosed by angiography in 202 (40%) of the 500 patients in the first group. A diagnostic algorithm was developed that includes the identification of three symptoms (sudden onset dyspnea, chest pain, and fainting) and their association with one or more of the following abnormalities: electrocardiographic signs of right ventricular overload, radiographic signs of oligemia, amputation of hilar artery, and pulmonary consolidations compatible with infarction. The above three symptoms (singly or in some combination) were associated with at least one of the above electrocardiographic and radiographic abnormalities in 164 (81%) of 202 patients with confirmed PE and in only 22 (7%) of 298 patients without PE. The rate of correct clinical classification was 88% (440/500). In the validation group of 250 patients the prevalence of PE was 42% (104/250). In this group, the sensitivity and specificity of the clinical diagnostic algorithm for PE were 84% (95% CI: 77 to 91%) and 95% (95% CI: 91 to 99%), respectively. The rate of correct clinical classification was 90% (225/250). Combining clinical estimates of PE, derived from the diagnostic algorithm, with independent interpretation of perfusion lung scans helps restrict the need for angiography to a minority of patients with suspected PE.

<b>A Simplified Clinical Model to Predict Pulmonary Embolism in Patients With Acute Dyspnea</b>

“…Previous 13-16) structured clinical models for early pretests of the proba- [13][14][15][16] placed relatively large proportions of patients in the intermediate probability category, which was of limited utility to both physicians and patients. Furthermore, previous models used suspected PE instead of specific symptoms as the initial inclusion criterion for patient recruitment.…”

“…[13][14][15][16] This criterion, however, lacked a clear definition because, in part, different physicians had different perceptions of suspected PE. These models, therefore, led to heterogeneous populations predicted to have PE, which undoubtedly led to variable pretest probabilities [13][14][15][16] and the low accuracy of these models. [14][15][16] Consequently, these models were of limited value in clinical practice.…”

Pulmonary embolism: an unsuspected killer

“…The classic findings of hemoptysis, dyspnea, and chest pain are insensitive and nonspecific for a diagnosis of PE, with fewer than 20% having this classic triad. The incidence of common symptoms in patients suspected of having PE is depicted in Table 1 [38]. One prospective observational study found that the single historical finding most sensitive for PE was unexplained dyspnea.…”

“…Table 1 shows the prevalence of various signs in patients suspected of having PE [38]. Although other studies reveal tachypnea to be the most sensitive clinical sign, it is absent in 5% to 13% of cases of PE [34,40].…”

Diretriz de Embolia Pulmonar

“…Nos pacientes estáveis clinicamente, a dispnéia e a dor torácica são os sintomas mais freqüentes 42,43 . No estudo PIOPED (Prospective Investigators of Pulmonary Embolism Diagnosis) a dispnéia esteve presente em 73% e a dor torácica tipo pleurítica, em 66% dos pacientes 44 .…”