Original Title: Análisis de situación, revisión sistemática y validación de un algoritmo diagnóstico del tromboembolismo pulmonar (TEP) en los servicios de urgencias hospitalarias del Servicio Vasco de Salud

Authors' objectives: • Main: — Establish a multidisciplinary consensus on what diagnostic tests must be requested and in which order for a more efficient and efficacious diagnostic protocol of PTE based on the best scientific evidence and taking into consideration the specific characteristics of our environment (health system and characteristics of patients). • Secondary: — Analyse the epidemiology, clinical characteristics, morbidity-mortality and hospital admission rates among patients admitted with PTE to the emergency service of a tertiary hospital. — Carry out an overview through a critical analysis of articles, protocols, guidelines, recommendations and standards relating to the use of standardised clinical algorithms in order to stratify the seriousness of patients with clinically suspected pulmonary thromboembolism. — Determine the measurement accuracy of: the Wells and Geneva scales and D-dimers in patients with clinically suspected PTE. — Identify variables that relate to PTE in our environment in order to reduce unnecessary diagnostic procedures while ensuring the safety and quality of treatment.

Authors' results and conclusions: Six hundred and thirty-seven patients suspected of PTE were assessed in the emergency service over the study period, of which 96 were finally diagnosed with PTE (15.1 %). Seventy-five patients of those not diagnosed with PTE were examined again in the emergency service and only one of them was diagnosed with PTE. The average age of patients with PTE was 69.25 years (range: 2295 years); 51 % were women. The main comorbidities: AHT (43.8 %), neurological disease (25 %), active neoplasia (22,9 %), chronic pulmonary disease (21.9 %) and AF (11.4 %). 7.3 % had had PTE previously and 10.4 % had had deep vein thrombosis (DVT). 3.1 % of patients were anticoagulated and 21.9 % were antiaggregated. Four patients had a hypercoagulability study, being positive in all cases. The main symptom consulted was progressive dyspnoea (46.7 %), followed by acute dyspnoea (20.9 %), syncope (15.6 %), pleuritic chest pain (4.4 %) and chest pain (4.4 %). Fourteen patients had signs of DVT. By analysing the vital signs on admission, 5.2 % had hypotension, 41.7 % tachycardia, 22.9 % tachypnea and 76.4 % hypoxaemia. The average D-dimer was 2475.50 ng/mL (range: 0-21.128 ng/mL). Forty patients (6.2 %) were also diagnosed with DVT. All patients with PTE diagnoses were hospitalised and in 10 cases were given intensive care. The average hospital stay was 9.5 days and in the case of intensive care, this was 3.5 days. The percentage of deaths associated with PTE was 10.4 % (10 patients). For the Wells scale, the NPV was 85.3 %, the PPV 62.5 %, 15.6 % sensitivity, 98.1 % specificity, LR+ 8.32 (IC 95 % = 3.75-18.45) and LR– 0.86 (IC 95 % = 0.78-0.95). For the Geneva scale, the NPV was 82.8 %, the PPV 58.8 %, 11.8 % sensitivity, 98.1 % specificity, LR+ 6.2 (IC 95 % = 2.42-15.74) and LR– 0.90 (IC 95 % = 0.81-1.00). For the Geneva scale, the NPV was 99.1 %, the PPV 21.6 %, 98.9 % sensitivity, 25.8 % specificity, LR+ 1.33 (IC 95 % = 1.26-1.41) and LR– 0.04 (IC 95 % = 0.01-0.29). The area under the ROC curve was 0.78 (IC 95 % = 0.73-0.83) for the Wells scale, 0.58 (IC 95 % = 0.51-0.65) for the Geneva scale and 0.84 (IC 95 % = 0.79-0.88) for the D-dimers. In order to validate the algorithm, patients with exclusion criteria such as the following were excluded: no clinical probability data, no results of diagnostic tests (TC or EVEI) or with previous anticoagulant treatment; and with violations of the protocol, such as: contra-indication/impossibility to carry out TC, life expectancy lower than three months, diagnosis prior to admission or others; therefore the final sample consisted of 515 patients. Of the 482 patients with non high clinical probability, 124 (25.7 %) had a negative result in the D-dimers test and no thromboembolic event in the three months of monitoring (risk 0.0 %; IC 95 % = 0.0-2.9). In patients with non high probability, the helical TC was positive for PTE in 71 patients. The EVEI and the helical TC were negative in 283 pacientes with positive D-dimers, in which a thrmoboembolic event was disagnosed in the three months of monitoring and no deaths (the thromboembolic risk was 0.35 %; IC 95 % = 0.01-2.0). Four patients with negative helical TC had a PPV (1.2 %, IC 95 % = 0.5-2.8) and were treated. Both the overall thromboembolic risk and the risk in patients in which PTE had been discarded without venous echography of EEII was the same when combining both scales. For the logistic regression analysis, patients with incomplete data were excluded and the final analytical sample was made up of 418 patients. Seventy-five variables were measured including blood analysis parameters, and 27 variables predictive of having PTE in a bivariate manner were found. Our final model consisted of 5 factors of those listed: Hypotension (Average Arterial Tension < 70 mmHg) (OR = 5.86; IC 95 % = 1.37-25.01; β = 1.76), PaCO2 < 36 mmHg (OR = 10.26; IC 95 % = 2.84-37.05; β = 2.32), PaCO2 36-38,9 mmHg (OR = 4.19; IC 95 % = 0.99-17.76; β = 1.43), Hyponatremia (OR = 16.19; IC 95 % = 2.38-110.18; β = 2.78), Positive troponymy (OR = 4.41; IC 95 % = 1.65-11.77; β = 1.48) and S1 Q3 T3 (OR = 47.85; IC 95 % = 2.11-1083.84; β = 3.86). The proposed model has an area under the ROC Curve of 0.83 (IC 95 % = 0.75-0.91). The diagnostic precision values observed are as follows: NPV 86.6 %, PPV 86.4 %, sensitivity 26.4 %, specificity 99.1, LR+ 30.44 (IC 95 % = 9.25-100.13) and LR– 0.74 (IC 95 % = 0.78-0.86). CONCLUSIONS Suspected PTE is a typical cause of admission to hospital emergency services and is normally resolved without complications. In some cases, determining the characteristics of patients who seek care for suspected PTE may help to improve the diagnostic, reducing unnecessary admissions that might complicate the prognosis. This may lead to a better knowledge of the causes of PTE and these variables explain the greater severity and the worst prognosis in our environment. In accordance with the results obtained, the Wells and Geneva scales are good candidates for use in our environment to predict the seriousness or severity of patients with suspected PTE, Wells being the scale of choice due to its greater specificity. However, none of them can be used as a diagnostic tool due to its low sensitivity. On the other hand, D-dimers are good candidates for use as a diagnostic tool when the seriousness of the condition has been established by other means. The combined use of the different diagnostic tools available such as scales, D-dimers and the helical TC must be utilised in order to improve the quality of care and the efficiency of the handling of patients with suspected PTE in hospital emergency services. The variables that are associated with the probability of PTE in our context are different to those proposed in other models, which suggests that, at least the validity of the existing skills must be tested in practice in order to be of use in the emergency services in each context and it would be interesting to validate scales or models more closely adjusted to each population.

Authors' methods: In order to respond to these four objectives, we designed the following types of studies and their materials and methods. • Transversal study including patients aged over 14 suspected of PTE, cared for in our emergency service. Data has been collected through a specific form and clinical history. • Design of a diagnostic precision study of the suspicion of PTE using the Wells and Ginebra scales and the D-dimers. The main results were as follows: sensitivity, specificity, positive and negative predictive values (PPV and NPV) and likelihood ratios (LR+ and LR-). The PTE diagnosis was confirmed through the helical TC (considered to be the Gold Standard). • Prospective study to validate a diagnostic algorithm and monitoring of the development (for three months) of the ETV at a single centre in the Basque Autonomous Community (Cruces University Hospital). This was done by analysing all suggestive cases of PTE, by gathering variables of the different valuation scales and required diagnostic tests based on risk weight. • Bivariate regression analysis, PTE being the explanatory variable. A logistic regression in order to predict the clinical parameters associated with PTE, such as: age, sex, related signs and symptoms, risk factors, concomitant diseases, laboratory findings, thorax radiographic results and electrocardiographic signs.

Project Status: Completed

Year Published: 2013

URL for published report: https://www.euskadi.eus/contenidos/informacion/2013_osteba_publicacion/es_def/adjuntos/Informe%20D-13-12%20Tromboembolismo.pdf

English language abstract: An English language summary is available

Publication Type: Other

Country: Spain

Organisation Name: Basque Office for Health Technology Assessment

Contact Address: C/ Donostia – San Sebastián, 1 (Edificio Lakua II, 4ª planta) 01010 Vitoria - Gasteiz

Contact Name: Lorea Galnares-Cordero

Contact Email: lgalnares@bioef.eus

Copyright: <p>Osteba (Basque Office for Health Technology Assessment) Health Department of the Basque Government</p>