Nomogram for hospital-acquired venous thromboembolism among patients with cardiovascular diseases

Fig. 1. Flow diagram of participant enrollment and exclusion. VTE, venous thromboembolism

Fig. 2. Nomogram for predicting hospital-acquired VTE in patients with cardiovascular diseases. ACS, acute cardiovascular syndrome; CMP, cardiomyopathy; CVC, central venous catheterization; IABP, intra-aortic balloon pump; PH, pulmonary hypertension; VTE, venous thromboembolism. In order to calculate the probability of hospital-acquired VTE, draw a vertical line straight upward from the predictor to the points axis to obtain the value, then sum the points of each predictor, this sum on the total points axis of the nomogram corresponded with the probability of hospital-acquired VTE, which can be determined by drawing a vertical line downward. For example, for a 60-year old female patient who had received central venous catheterization and was immobile during hospitalization without other risk factors and did not receive anticoagulants, the total points (156) = female sex (12 points) + 60 years old (60 points) + immobility (64 points) + central venous catheterization (20 points), and the probability of VTE was about 15%

Fig. 3. Calibration curve of nomogram. Calibration curve indicated high accuracy of nomogram in predicting VTE

Fig. 4. Receiver operator characteristic curve of Padua score and Fuwai nomogram. AUC, area under curve; 95% CI, 95% confidence interval

Fig. 5. Decision curve analysis of Padua score and Fuwai nomogram. In the context of decision curve analysis, the x-axis illustrates threshold values for risks of VTE, whereas the y-axis denotes the net benefit for different cutoffs of primary endpoint risk. The greater the deviation of prediction models from the grey line and the horizontal black line, the greater the corresponding net benefit. The Fuwai nomogram demonstrated the larger net benefit across the range of risk of hospital-acquired VTE compared with Padua score. As the guideline suggested, Padua score was categorized two categories. Low risk is defined as Padua score < 4 points, high risk is defined as Padua score ≥ 4 points, in line with 9th American College of Chest Physicians Evidence-Based Clinical Practice Guidelines [4]