Simplified VTE Protocol Rules Out Pulmonary Embolism, Reduces Use of CT Imaging: YEARS Study

ROME, Italy—In patients with suspected venous thromboembolism, use of a clinical algorithm that relies on a simplified scoring system for risk stratification and D-dimer testing can safely exclude pulmonary embolism while simultaneously reducing the use of computed tomography pulmonary angiography (CTPA).

Those are the main conclusions of the YEARS study, which was presented earlier this week at the European Society of Cardiology Congress 2016 in Rome, Italy, by Tom van der Hulle, MD (Leiden University Medical Center, the Netherlands). “There is still a large majority of CT scans performed in patients without pulmonary embolism,” van der Hulle told TCTMD. “We’re doing more and more CT scans without diagnosing more pulmonary embolism. We know this from observational studies and also from clinical experience.”

van der Hulle added that the majority of patients with suspected pulmonary embolism are sent for a CT scan from the emergency department. One of the problematic aspects of the condition is that symptoms are nonspecific, making diagnosis difficult. Currently, physicians assess the clinical probability of pulmonary embolism using the Wells score or the revised Geneva score, two risk-stratification tools based on patient symptoms.

Presenting the results of the YEARS study to the media, van der Hulle said the current treatment algorithm excludes pulmonary embolism in approximately 20% to 30% of patients, but the majority of CT scans are still negative. Also, adherence in clinical practice to the algorithm varies, mainly because it’s quite complex and requires sequential testing. For example, using the Wells/Geneva risk stratification tools, physicians must assess seven to nine variables as part of clinical work-up.

With the YEARS protocol, D-dimer testing is performed in all patients immediately—as opposed to selective use in other scoring tools—and clinical assessment performed using just three items of the original Wells venous thromboembolism risk score. The three components of the modified score include an assessment of clinical signs of deep vein thrombosis (such as swelling or edema), hemoptysis, and whether the clinician considers pulmonary embolism to be the most likely diagnosis.

If the D-dimer level is less than 1000 ng/mL, and the YEARS protocol reveals zero items in risk stratification, pulmonary embolism is excluded. If the D-dimer level is ≥ 1000 ng/mL, CTPA is ordered. For those with one or more items on the modified YEARS protocol, pulmonary embolism can be excluded if the D-dimer test shows a level less than 500 ng/mL. Additionally, a CT scan is ordered if the D-dimer level is ≥ 500 ng/mL in those with one or more YEARS risk items.

In their study, which included 2,944 patients with suspected pulmonary embolism, CTPA was not needed in 48% of patients. For the 1,306 patients where pulmonary embolism was excluded based on a YEARS score of zero and D-dimer level less than 1000 ng/mL, there were two nonfatal events (one pulmonary embolism, one deep vein thrombosis) using the simplified rule-out protocol. In 327 patients with one or more items on the YEARS score, but where pulmonary embolism was ruled out based on the D-dimer level less than 500 ng/mL, there were three nonfatal pulmonary embolisms detected at baseline.

Overall, venous thromboembolism occurred in 0.61% of the population, with fatal pulmonary embolism occurring in 0.20% of patients. For the 1,629 patients managed without CTPA, the venous thromboembolism and fatal pulmonary embolism event rates were 0.43% and 0.12%, respectively. For those managed with CTPA, the event rates were 0.84% and 0.30%, respectively.

Speaking with the media, van der Hulle said the YEARS algorithm can safely exclude pulmonary embolism and significantly reduce the number of CT scans. In their study, there was a 14% reduction in the number of CT scans ordered (when compared with standard rule-in/rule-out protocols).

The new algorithm is already in use in 12 hospitals throughout the Netherlands. As to whether or not more hospitals and physicians will adopt it, particularly for reducing the use of CTPA, van der Hulle noted the YEARS protocol does include the item asking whether pulmonary embolism is the most likely diagnosis, which is also used in the Wells score. For the overly cautious, they might simply send the patient on to CTPA, he said, but added that physicians are also wary of radiation exposure.

van der Hulle reported that a cost-effective analysis is planned, as is a study testing the protocol in pregnant women with suspected pulmonary embolism.

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