European Journal of Cardiovascular Medicine

Pulmonary embolism (PE) is a potentially fatal condition caused by obstruction of the pulmonary arteries, most often by thrombi originating from deep vein thrombosis (DVT) ^[1]. It remains a significant cause of morbidity and mortality worldwide, particularly due to its nonspecific and variable clinical presentation ^[2]. Timely and accurate diagnosis is essential, as untreated PE carries a high mortality rate, while prompt treatment drastically reduces the risk of fatal outcomes ^[3].

Given the diagnostic challenges, several clinical prediction rules (CPRs) have been developed to estimate the pretest probability of PE and guide further investigations. Among these, the Wells score ^[4] and the revised Geneva score ^[5] are the most widely used and validated in clinical practice. The Wells score, originally proposed in 1998, combines objective signs with subjective clinical judgment, categorizing patients into low, moderate, or high risk ^[4,6]. In contrast, the revised Geneva score was designed to be entirely objective and reproducible, using only clinical variables that require no physician judgment ^[5,7].

Studies have consistently shown that using these scores in combination with D-dimer testing improves diagnostic efficiency and reduces unnecessary imaging ^[8,9]. In a prospective study by Douma et al., both scores demonstrated similar accuracy in excluding PE when combined with negative D-dimer results in low-risk patients ^[10]. The simplified versions of these scores have also been validated and offer improved usability without compromising diagnostic accuracy ^[11,12].

However, studies comparing the diagnostic performance of the Wells and Geneva scores have shown variable results across different populations. Some research suggests that the Wells score may have slightly better sensitivity in emergency settings ^[13], while others advocate for the Geneva score in standardized environments where physician experience may vary ^[14,15]. A systematic review by Ceriani et al. concluded that no single CPR is universally superior, and clinical context remains crucial ^[16].

Advancements in imaging, particularly CT pulmonary angiography (CTPA), have transformed PE diagnosis, but concerns remain regarding overuse, radiation exposure, and contrast-induced nephropathy ^[17,18]. Thus, reliance on CPRs like the Wells and Geneva scores remains critical to risk stratify patients before ordering imaging ^[19].

This prospective observational study aims to evaluate and correlate the Wells score and revised Geneva score with confirmed diagnoses of PE. By directly comparing their predictive accuracy in a clinical setting, the study seeks to identify the more effective tool for risk stratification and diagnostic decision-making in suspected PE cases.

Study Design

This study was designed as a prospective observational study, aimed at evaluating the correlation between two widely used clinical prediction rules—the Wells Score and the Revised Geneva Score—and confirmed diagnoses of pulmonary embolism (PE). The prospective design allowed for real-time data collection, risk assessment at the time of presentation, and unbiased confirmation of diagnosis through radiological imaging. The observational nature of the study ensured that no intervention influenced the clinical pathway beyond the standard of care.

A prospective observational study was conducted at tertiary care centers, one in Chhattisgarh and other in Maharashtra, India, over 14 months

Study Setting

The study was conducted at two tertiary care centers, one in  Chhattisgarh and other in Maharashtra, India (over 14 months), which serves as a major referral center for both urban and rural populations. The hospital is equipped with the necessary diagnostic infrastructure, including D-dimer testing, color Doppler ultrasonography, echocardiography, and multidetector CT pulmonary angiography (CTPA), allowing for accurate and confirmatory diagnosis of suspected pulmonary embolism. The availability of these facilities ensured consistent diagnostic protocols throughout the study period.

Study Duration

The data collection for the study was carried out over a 14-month period, from February 2024 to April 2025, ensuring the inclusion of patients across all seasons and accounting for variations in patient load and presentation over time. A dedicated team of trained physicians and postgraduate students was responsible for the recruitment and assessment of eligible patients.

Study Population

The study population consisted of adult patients (≥18 years) who presented to the Emergency Department or Medicine Outpatient Department with symptoms suggestive of pulmonary embolism. These symptoms included sudden-onset breathlessness, pleuritic chest pain, hemoptysis, syncope, tachycardia, hypoxia, and signs of deep vein thrombosis (DVT) such as unilateral lower limb swelling and tenderness. These clinical features formed the basis of suspicion and subsequent risk stratification using the Wells and Revised Geneva Scores.

Inclusion Criteria

Patients were eligible for inclusion if they were aged 18 years or older and presented with clinical signs and symptoms suggestive of acute PE. All patients were required to provide written informed consent before participating in the study. Patients referred from other departments or outpatient clinics for suspected PE were also evaluated for inclusion based on the same criteria. The inclusion aimed to capture a wide range of cases, including both ambulatory and hospitalized patients.

Exclusion Criteria

Patients were excluded from the study under the following conditions: (1) if they had been on therapeutic anticoagulation for more than 48 hours before presentation, as this could affect both the clinical picture and radiological findings; (2) if they were pregnant, due to radiation risks associated with CTPA; (3) if they had known hypersensitivity to iodinated contrast agents; (4) if they had severe renal impairment (eGFR <30 ml/min/1.73 m²), which contraindicated contrast use; and (5) if they had incomplete records, were lost to follow-up, or refused consent. These criteria ensured the integrity and safety of the study.

Sample Size

The sample size was determined based on prior studies that evaluated the sensitivity and specificity of the Wells and Revised Geneva scores. Assuming a PE prevalence of approximately 25% in suspected patients and a confidence level of 95% with a 8% allowable error, the minimum calculated sample size was 120 patients. This sample size allowed for adequate statistical power to compare diagnostic performance and conduct ROC curve analysis.

Scoring Systems and Risk Stratification

Upon presentation, each patient was assessed clinically, and both the Wells Score and the Revised Geneva Score were calculated using standard published criteria. The Wells Score includes clinical signs of DVT, previous PE/DVT, heart rate, hemoptysis, malignancy, recent surgery or immobilization, and the physician’s subjective judgment. The Revised Geneva Score, on the other hand, uses objective variables such as age, heart rate, previous DVT/PE, hemoptysis, surgery or fracture, unilateral leg pain, and pain on deep vein palpation without requiring clinical judgment. Patients were categorized as low, moderate, or high risk for PE based on each scoring system.

Diagnostic Evaluation

After risk stratification, patients in the low-risk category underwent D-dimer testing using an ELISA-based quantitative assay. If the D-dimer was below the institutional cutoff (<500 ng/mL), PE was considered unlikely, and no further imaging was done unless clinically indicated. Patients with moderate or high risk, or those with elevated D-dimer levels, underwent CT pulmonary angiography (CTPA), which served as the gold standard for diagnosing PE. In cases where CTPA was contraindicated (e.g., renal insufficiency or contrast allergy), Doppler ultrasound of lower limbs and transthoracic echocardiography (TTE) were used to support the diagnosis, especially in patients with right ventricular strain or visible DVT.

Outcome Definition and Confirmation of PE

A diagnosis of confirmed PE was established when there was direct radiological evidence of thrombus in the pulmonary arteries on CTPA, characterized by intraluminal filling defects. In patients who underwent alternative testing, PE was diagnosed based on indirect but strong clinical and radiological correlation, such as Doppler-confirmed DVT with echocardiographic signs of right heart strain. Patients with no radiological or clinical evidence of thromboembolism were categorized as non-PE cases.

Data Collection Tools

A pre-validated case record form (CRF) was used to document patient demographics, clinical features, scoring results, laboratory investigations, radiological findings, and final diagnosis. The data was anonymized, double-checked for accuracy, and stored in a secure digital database accessible only to the research team. This ensured uniformity and completeness of collected information.

Statistical Analysis

Data were analyzed using IBM SPSS version 25.0. Descriptive statistics were used to summarize demographic variables and clinical characteristics. Categorical variables (e.g., PE status, score categories) were expressed as frequencies and percentages, while continuous variables (e.g., age, heart rate) were reported as mean ± standard deviation (SD). The Chi-square test or Fisher’s exact test was applied to compare proportions between groups. The diagnostic accuracy of each scoring system was assessed using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Further, Receiver Operating Characteristic (ROC) curve analysis was used to compare the area under the curve (AUC) of the Wells and Geneva scores, with a higher AUC indicating better diagnostic performance. A p-value of <0.05 was considered statistically significant.

The study population (n=120) had a mean age of 54.2 years, with a slight male predominance (55.8%). The average heart rate and respiratory rate were elevated, reflecting clinical suspicion of PE. Mean oxygen saturation at presentation was 91.7%, indicating mild hypoxia. Notably, 19.2% had a prior history of DVT/PE, 11.7% had active malignancy, 23.3% had recent surgery or immobilization, and 9.2% presented with hemoptysis—highlighting the presence of classic PE risk factors

The majority of patients were classified as moderate risk by both the Wells Score (42.5%) and the Revised Geneva Score (48.3%). Low- and high-risk categories were similarly distributed between the two scoring systems. The difference in risk stratification was not statistically significant (χ² = 0.85, p = 0.654), indicating good concordance between the Wells and Geneva scores in categorizing patient risk levels.

There was a clear trend of increasing pulmonary embolism (PE) confirmation rates with higher risk categories for both the Wells and Revised Geneva scores. Among patients classified as high risk, PE was confirmed in 77.4% (Wells) and 81.5% (Geneva). In contrast, the confirmation rates were considerably lower in the low-risk groups—10.5% (Wells) and 8.6% (Geneva).

Both the Wells Score and the Revised Geneva Score demonstrated high diagnostic performance in predicting pulmonary embolism. The Wells Score showed slightly higher sensitivity (84.3% vs. 82.3%), specificity (71.4% vs. 69%), and overall accuracy (75% vs. 73.3%) compared to the Geneva Score. Similarly, the Wells Score had marginally better positive and negative predictive values.

ROC curve analysis demonstrated excellent diagnostic performance for both scoring systems. The Wells Score achieved an AUC of 0.842 (95% CI: 0.773–0.911), while the Geneva Score had an AUC of 0.821 (95% CI: 0.752–0.890), with both results statistically significant (p < 0.001).

D-dimer positivity increased consistently with higher clinical risk categories in both the Wells and Revised Geneva scoring systems. Among high-risk patients, D-dimer was positive in 96.8% (Wells) and 96.3% (Geneva), while positivity was lowest in the low-risk groups—65.8% (Wells) and 68.6% (Geneva).

In 12 patients where CTPA was contraindicated, alternative diagnostic modalities were employed. Combined Doppler ultrasound and transthoracic echocardiography (TTE) confirmed pulmonary embolism in 58.3% of cases. DVT was detected in 75%, and right ventricular (RV) strain was observed in 50% of patients.

This prospective observational study evaluated and compared the diagnostic accuracy of the Wells Score and the Revised Geneva Score in predicting pulmonary embolism (PE) among 120 suspected cases.

Demographic and Clinical Characteristics

The mean age of the participants was 54.2 years, with a slight male predominance (55.8%). Common risk factors observed included prior DVT/PE (19.2%), malignancy (11.7%), recent immobilization or surgery (23.3%), and hemoptysis (9.2%), which are in line with previous studies on PE epidemiology by Stein and Matta (2010) ^[1] and Goldhaber and Bounameaux (2012) ^[2].

Risk Stratification

As shown in Table 2, both the Wells and Geneva scores categorized the majority of patients into the moderate-risk group (42.5% and 48.3%, respectively), with no statistically significant difference in the distribution (p = 0.654). This is consistent with findings from Penaloza et al. (2012), who concluded that both scoring systems yield similar pretest probability distributions in clinical settings ^[16].

Correlation with Confirmed PE

Table 3 reveals that PE confirmation increased with higher risk categories in both scoring systems: 77.4% in the high-risk group for Wells and 81.5% for Geneva, with only 10.5% and 8.6% positivity in the low-risk categories. These results are consistent with Le Gal et al. (2006) ^[5] and Di Marca et al. (2015) ^[15], supporting the validity of both CPRs in stratifying PE risk.

Diagnostic Accuracy

In Table 4, the Wells Score showed slightly higher sensitivity (84.3% vs 82.3%), specificity (71.4% vs 69%), and overall accuracy (75% vs 73.3%) compared to the Geneva Score. This finding corroborates the original validation of the Wells Score by Wells et al. (1998) ^[4] and the simplification work by Gibson et al. (2008) ^[6], both of whom demonstrated its clinical effectiveness in emergency departments.

ROC Curve Analysis

ROC curve analysis (Table 5) confirmed excellent discrimination by both scoring systems. The AUC for the Wells Score was 0.842, and for the Geneva Score 0.821, both statistically significant (p < 0.001). These values align with the meta-analysis by Ceriani et al. (2010) ^[17], who found no universal superiority between the two but validated both for clinical use.

D-dimer Trends

Table 6 demonstrates that D-dimer positivity increased with rising clinical probability: 96.8% in high-risk (Wells) and 96.3% (Geneva), with much lower positivity in the low-risk categories. This trend supports the findings of van Belle et al. (2006) ^[8] and Righini et al. (2006) ^[9], who emphasized the utility of combining D-dimer testing with CPRs to safely exclude PE in low-risk patients.

Alternative Diagnostic Modalities

In patients where CTPA was contraindicated (Table 7), 58.3% had PE confirmed using Doppler and echocardiography. DVT was present in 75%, and RV strain in 50% of these cases. These findings highlight the role of non-invasive imaging, consistent with the recommendations of Roy et al. (2006) ^[11] and Stein et al. (2006) ^[18], especially when contrast studies are not feasible.

The study reaffirms the clinical applicability of both the Wells and Revised Geneva Scores in PE risk stratification and diagnosis. While both tools performed well, the Wells Score demonstrated marginally higher accuracy. Integration of these scores with D-dimer testing enhances their diagnostic value, supporting their continued use in emergency and outpatient settings.

Limitations:
This single-center study may limit generalizability to broader populations. The use of alternative diagnostic methods in some patients could affect consistency. The modest sample size restricted subgroup analysis, and the subjective elements of the Wells Score may introduce observer bias. Additionally, long-term patient outcomes were not assessed.

Conflict of Interest:

The authors declare no conflict of interest related to this study

1. Kearney PM, Whelton M, Reynolds K, Muntner P, Stein PD, Matta F. Epidemiology and incidence of acute pulmonary embolism: an overview. Clin Chest Med. 2010;31(4):611–628.
2. Goldhaber SZ, Bounameaux H. Pulmonary embolism and deep vein thrombosis. Lancet. 2012;379(9828):1835–1846.
3. Kearon C. Natural history of venous thromboembolism. Circulation. 2003;107(23 Suppl 1):I22–30.
4. Wells PS, Ginsberg JS, Anderson DR, et al. Use of a clinical model for safe management of patients with suspected pulmonary embolism. Ann Intern Med. 1998;129(12):997–1005.
5. Le Gal G, Righini M, Roy PM, et al. Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Ann Intern Med. 2006;144(3):165–171.
6. Gibson NS, Sohne M, Kruip MJ, et al. Further validation and simplification of the Wells clinical decision rule in pulmonary embolism. Thromb Haemost. 2008;99(1):229–234.
7. Klok FA, Mos IC, Nijkeuter M, et al. Simplification of the revised Geneva score for assessing clinical probability of pulmonary embolism. Arch Intern Med. 2008;168(19):2131–2136.
8. van Belle A, Büller HR, Huisman MV, et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172–179.
9. Righini M, Le Gal G, Aujesky D, et al. Clinical usefulness of D-dimer testing in cancer patients with suspected pulmonary embolism. Thromb Haemost. 2006;95(4):715–719.
10. Douma RA, Mos IC, Erkens PM, et al. Performance of 4 clinical decision rules in the diagnostic management of acute pulmonary embolism: a prospective cohort study. Ann Intern Med. 2011;154(11):709–718.
11. Roy PM, Meyer G, Vielle B, et al. Appropriateness of diagnostic management and outcomes of suspected pulmonary embolism. Ann Intern Med. 2006;144(3):157–164.
12. Wicki J, Perneger TV, Junod AF, et al. Assessing clinical probability of pulmonary embolism in the emergency ward: a simple score. Arch Intern Med. 2001;161(1):92–97.
13. Kabrhel C, Camargo CA Jr, Goldhaber SZ. Clinical gestalt and the diagnosis of pulmonary embolism: does experience matter? Chest. 2005;127(5):1627–1630.
14. Di Marca S, Cilia C, Campagna A, et al. Comparison of Wells and Revised Geneva Rule to Assess Pretest Probability of Pulmonary Embolism in High-Risk Hospitalized Elderly Adults. J Am Geriatr Soc. 2015;63(6):1091–1097.
15. Penaloza A, Verschuren F, Meyer G, et al. Comparison of the Wells score with the simplified revised Geneva score for assessing pretest probability of pulmonary embolism. Thromb Res. 2012;130(5):e133–e138.
16. Ceriani E, Combescure C, Le Gal G, et al. Clinical prediction rules for pulmonary embolism: a systematic review and meta-analysis. J Thromb Haemost. 2010;8(5):957–970.
17. Stein PD, Fowler SE, Goodman LR, et al. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med. 2006;354(22):2317–2327.
18. Anderson DR, Kahn SR, Rodger MA, et al. Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial. JAMA. 2007;298(23):2743–2753.
19. Freund Y, Cachanado M, Aubry A, et al. Effect of the Pulmonary Embolism Rule-Out Criteria on Subsequent Diagnostic Testing in Low-Risk Emergency Department Patients: A Randomized Clinical Trial. JAMA. 2018;319(6):559–566.