Clinical probability scoring and pulmonary embolism
Date First Published:
April 10, 2003
Last Updated:
July 2, 2003
Report by:
Ged Brown, Specialist Registrar (Manchester Royal Infirmary)
Search checked by:
Kerstin Hogg, Manchester Royal Infirmary
Three-Part Question:
In [a patient presenting with features suggestive of pulmonary embolus] what is [the diagnostic utility of clinical assessment] in [stratifying risk of pulmonary embolus]?
Clinical Scenario:
A 30 year old man presents to the emergency department with a spontaneous onset of atraumatic pleuritic chest pain. He has no previous medical history and has no shortness of breath or haemodynamic compromise. You wonder whether his clinical features and risk factors can help to safely exclude a pulmonary embolus.
Search Strategy:
Medline 1966-06/03 using the OVID interface.
Search Details:
(exp Pulmonary Embolism OR exp THROMBOEMBOLISM OR PE.mp OR pulmonary infarct$.mp OR Pulmonary Embol$.mp) AND (exp Risk Assessment OR risk assessment.mp OR risk stratification.mp OR probability.mp) LIMIT to human AND English language
Outcome:
938 papers were found of which 935 papers were irrelevant to the question, of insufficient quality or did not report a mathematically derived scoring systems. The remaining 4 are included in the table below. N.B. The clinical scoring systems have not been represented in this table. Please refer to the individual papers for these details.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Wells PS, Anderson MR, Ginsberg JS, et al. 2000, Canada | 964 (derivation) and 247 (validation) patients referred for V/Q scan from earlier cohort | Retrospective clinical decision rule study | % of patients with PE in low risk | 7.8% (5.9-10.1) in derivation group, 5.1% (2.3-9.4) in validation set | Use of previous cohort of patients Includes inpatients |
| Assessing clinical probability of pulmonary embolism in the emergency ward: A simple score. Wicki J, Perneger TV, Junod AF, et al. 2001, Switzerland | 1090 emergency ward patients with suspected PE Decision rule developed which divides patients into low medium and high risk groups |
Prospective clinical decision rule study | Pretest probability of PE<br><br>Low<br><br>Medium<br><br>High | <br><br>10%<br><br>38%<br><br>81% | Reference standard included nondiagnostic scan No Validation study |
| Criteria for the safe use of D-dimer testing in emergency department patients with suspected pulmonary embolism: a multicenter US study. Kline JA, Nelson RD, Jackson RE, et al. 2002, USA | Convenience sample 934 patients presenting to 7 EDs, who underwent pulmonary vascular imaging for PE Decision rule developed which divides patients into high and low risk groups |
Prospective clinical decision rule study | Pretest probability of PE<br><br>Low<br><br>High | <br><br>13.3% (10.9–15.9)<br><br>42.1% (35.3-49.6) | The authors suggest that the decision rule would determine a low risk group suitable for application of a D-dimer test – this has yet to be validated. |
| A structured clinical model for predicting the probability of pulmonary embolism. Miniati M, Monti S, Bottai M. 2003, Italy | 1100 consecutive patients referred for investigation for PE | Derivation/Cross Validation study | Objective signs, risk factors, ECG and CXR recorded.Multivariate logistic regression established those associated with the diagnosis of PE | Scoring system developed which divides patients into low, intermediate, moderately high and high groups<br><br>Pre-test probability by group<br>Low- 4%<br>Intermediate- 22%<br>Moderately high- 74%<br>High- 98% | Subjective inclusion criteria No prospective validation study (cross validation only) |
Author Commentary:
There is evidence to suggest a variety of clinical models can be used to stratify patients into different levels of risk for PE. It is possible that these may be combined with other tests to give an acceptably low post-test probability of PE.
Bottom Line:
Clinical risk stratification is a potentially useful method of identifying low risk patients in whom PE may be safely excluded by simple non-invasive tests.
References:
- Wells PS, Anderson MR, Ginsberg JS, et al.. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer.
- Wicki J, Perneger TV, Junod AF, et al.. Assessing clinical probability of pulmonary embolism in the emergency ward: A simple score.
- Kline JA, Nelson RD, Jackson RE, et al.. Criteria for the safe use of D-dimer testing in emergency department patients with suspected pulmonary embolism: a multicenter US study.
- Miniati M, Monti S, Bottai M.. A structured clinical model for predicting the probability of pulmonary embolism.