Prospective multicenter evaluation of the pulmonary
embolism rule-out criteria
J. A. KLINE*, D. M. COURTNEY†, C. KABRHEL‡, C. L. MOORE§, H. A
SMITHLINE¶, M. C. PLEWA**, P. B. RICHMAN††, B. J. O'NEIL‡‡ and K.
NORDENHOLZ§§
*Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC ;
†Department of Emergency Medicine, Northwestern Memorial Hospital, Chicago,
IL ; ‡Department of Emergency Medicine, Massachusetts General Hospital,
Boston, MA ; §Department of Surgery, Yale University School of Medicine, New
Haven, CT ; ¶Department of Emergency Medicine, Baystate Medical Center,
Springfield, MA ; **Department of Emergency Medicine, St. Vincent Mercy
Medical, Toledo, OH ; ††Department of Emergency Medicine, Mayo Clinic,
Scottsdale, AZ ; ‡‡Department of Emergency Medicine, William Beaumont
Hospital, Royal Oak, MI ; and §§Department of Surgery, University of Colorado
School of Health Sciences, Denver, CO, USA
Correspondence to Jeffrey A. Kline, Emergency Medicine Research, Department
of Emergency, Medicine Carolinas Medical Center, PO Box 32861 Charlotte, NC
28323-2861, USA.
Tel.: +1 704 355 7092; fax: +1 704 355 7047.
E-mail: jkline@carolinas.org
KEYWORDS
computerized tomography angiography • D-dimer • decision rule • decisionmaking • diagnosis • medical malpractice • pulmonary embolism • venous
thromboembolism
ABSTRACT
Summary. Backgound: Over-investigation of low-risk patients with suspected
pulmonary embolism (PE) represents a growing problem. The combination of
gestalt estimate of low suspicion for PE, together with the PE rule-out criteria
[PERC(−): age < 50 years, pulse < 100 beats min−1, SaO2 ≥ 95%, no
hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within
4 weeks, no prior venous thromboembolism (VTE), and no unilateral leg
swelling], may reduce speculative testing for PE. We hypothesized that low
suspicion and PERC(−) would predict a post-test probability of VTE(+) or death
below 2.0%. Methods: We enrolled outpatients with suspected PE in 13
emergency departments. Clinicians completed a 72-field, web-based data form at
the time of test order. Low suspicion required a gestalt pretest probability
estimate of <15%. The main outcome was the composite of image-proven
VTE(+) or death from any cause within 45 days. Results: We enrolled 8138
patients, 85% of whom had a chief complaint of either dyspnea or chest pain.
Clinicians reported a low suspicion for PE, together with PERC(−), in 1666
patients (20%). At initial testing and within 45 days, 561 patients (6.9%, 95%
confidence interval 6.5–7.6) were VTE(+), and 56 others died. Among the low
suspicion and PERC(−) patients, 15 were VTE(+) and one other patient died,
yielding a false-negative rate of 16/1666 (1.0%, 0.6–1.6%). As a diagnostic test,
low suspicion and PERC(−) had a sensitivity of 97.4% (95.8–98.5%) and a
specificity of 21.9% (21.0–22.9%). Conclusions: The combination of gestalt
estimate of low suspicion for PE and PERC(−) reduces the probability of VTE to
below 2% in about 20% of outpatients with suspected PE.