WVU Charleston campus research into use of D-dimer in patient diagnosis could have significant time, cost and patient satisfaction implications
CHARLESTON, W.VA. - The results of D-dimer (DD) testing during the initial workup for patients with limb swelling/pain in the emergency room may limit the over-utilization and added cost of venous duplex ultrasound (VDU), without a negative impact on patient care, according to research conducted at by West Virginia University’s Health Sciences faculty at Charleston Area Medical Center. The study’s findings have been translated into practice. Albeir Y. Mousa, MD, FACS, RPVI, MPH, MBA, associate professor of surgery at West Virginia University Health Sciences Charleston Campus and his team, from the Center for Health Services and Outcomes Research, began to focus on the use of D-dimer through their work in the busy emergency departments at Charleston Area Medical Center in Charleston, W.Va. As they worked with patients presenting with limb swelling, the first inspiration that came to them to start their research was patient dissatisfaction in waiting for a long time to be seen and for test results to come back. In addition, Mousa noted that patients presenting with limb swelling who were sent for venous duplex ultrasound returned with more than 90 percent negative results.
“D-dimer (DD) is a blood component which usually gets elevated when we have any inflammatory or acute arterial pathology, including history of deep vein thrombosis (DVT),” Dr. Mousa said. “The sensitivity of DD in detecting DVT is remarkably high, however many institutions send patients immediately for a venous duplex ultrasound (VDU). Using a simple test, an acute DVT may be “ruled-out”, eliminating the need for the initial VDU and cutting the time of results dramatically.
Mousa and his team conducted two studies on the use of D-dimer. The first included 517 patients and the second expanded the scope to include more than 2,000 patients who presented to a high volume emergency department (ED) with lower extremity limb swelling/pain over a 30-day period, and who were sent for VDU during an evaluation for DVT. VDU data were merged with electronic DD lab results. The enzyme-linked immunosorbent assay (ELISA) method was used to provide DD values and thresholds.
Upon reviewing the medical records of the ED patients, after applying the Wells criteria, 30 percent patients were excluded due to a history of DVT or PE, having been screened for shortness of breath, or sent for surveillance; leaving 70 percent for analysis. Of the patients who were sent for VDU without DD; 13.9% were positive for DVT. However, 86.1% patients were negative for DVT by VDU without DD.
According to Mousa, the results of the DD test will save time, cost and involvement with going directly to the venous duplex ultrasound. We believe it will help to move patient in and out from the busy, tertiary center ER, like their own in Charleston. The cost savings of the unnecessary VDUs in the study sample alone could equal a charge savings of several hundreds of thousands of dollars.
“I think that this project has the potential to be adopted as one of the biggest quality improvement projects in our own institution,” Mousa said. “When it comes to utilization of the D-dimer, we have set up an algorithm for a physician to follow when they see any patient with limb swelling. If they can utilize the algorithm appropriately, they will go through certain steps which will require them getting D-dimer at a certain time of the initial workup with the patient.”
Mousa and his research team are excited that this type of research can lead to an evidence-based medicine approach that plays a critical part in ensuring that practitioners use the soundest available medical procedures while avoiding ineffective and unnecessary ones. “This study is a perfect example of translating research into practice,” Dr. Mousa said.
Dr. Mousa and his team think that the results of the study can be taken to many other levels. “The initial level is people with limb swelling,” Dr. Mousa said. “But DD is a very sensitive blood marker to many other pathologies, including the aortic dissection pathology. People with aortic dissection may have increased DD. When a patient comes in with back pain or with severe or high blood pressure, if the DD is negative, it is unlikely to have aortic dissection. Presently, many providers immediately use CT angio in such cases, a very costly test that involves injecting contrast in one of our large veins of the arm. It may hurt the kidney. It takes significant resources to transport patients to the CAT scan suite, get the testing done, and then transport them back to where they came from, and then waiting for radiology to have all of this. By utilizing a simple test, we can just answer this in the first fifteen minutes of a patient coming with these symptoms.”
Dr. Mousa feels that the DD study can also have an impact on diagnosis of elderly patients who come into the ED with back pain. A negative DD result can help to rule out aneurysm, kidney stones and related medical conditions.
Recent presentations by Dr. Mousa at medical conferences have created a great deal of discussion and interaction. “I think the D-dimer has panoramic potential in the near future, if we apply this effectively and smartly, we may have significant improvement when it comes to patient satisfaction and institution saving,” Dr. Mousa said.
Following Dr. Mousa’s study and based on the results and support in the literature, a QI project was initiated at the Charleston Area Medical Center’s Memorial and General Emergency Departments primarily by the ED faculty in April of 2017. Baseline data showed D-dimer testing was performed prior to venous duplex in only 5.8% of the patients. Extensive education ensued including posters being printed and hung in each ED. By the 2nd Quarter of 2017, 16% of patients had had a D-dimer test prior to venous duplex. Subsequent follow-up has noted that 11% of the patients had had a D-dimer test prior to venous duplex which has held steady though the first quarter of 2018. The overall use of D-dimer testing has increased by nearly 20 fold while the utilization of venous duplex overall has decreased by 40% for the past 3 quarters. It is difficult to quantify cost savings, however, D-dimer is a relatively inexpensive test, thus the overall net reduction in charges (increased for D-dimer, decreased for venous duplex) and average of $222,000 per quarter has been noted. This QI project continues and additional interventions are planned to improve the utilization of D-dimer as a screening tool for deep vein thrombosis in the ED in low risk patients.