In the JournalsPerspective

Compression ultrasonography ‘reliable tool’ for deep vein thrombosis diagnosis

General practitioners trained in compression ultrasonography showed substantial accuracy and agreement, suggesting the test can be a “reliable tool” in diagnosing symptomatic proximal deep vein thrombosis, according to findings recently published in Annals of Family Medicine.

“Lower limb deep vein thrombosis represents a diagnostic dilemma for general practitioners,” Nicola Mumoli, MD, of the department of internal medicine at Ospedeale Civile di Livorno in Italy, told Healio Family Medicine. “A rapid, accurate outpatient diagnosis could improve health care quality and avoid unnecessary in-hospital evaluation.”

Physicians with 10 or more years of experience in vascular compression ultrasonography provided general practitioners with 2 months of training that consisted of 12 hours of didactic lectures, 30 hours of practice on patients and 8 hours of image review.

Mumoli and colleagues then enrolled 1,107 outpatients with suspected deep vein thrombosis in a multicenter, prospective cohort study. One of the 18 newly trained general practitioners performed the compression ultrasonography — moving the transducer distally and applying gentle compression along a patient’s deep venous system. An expert vascular ultrasonography physician conducted the same test within 2 hours. Exams with nondiagnostic or negative results were completed again 5 to 7 days later. One of the eight well-versed physicians made the definitive diagnosis. Interobserver agreement was determined.

Researchers found that agreement between the two groups of physicians was excellent, with a weighted Cohen’s kappa statistic of 0.86 (95% CI, 0.84-0.88). In addition, agreement on the diagnosis of deep vein thrombosis was almost identical when both femoral and popliteal veins were affected (kappa = 0.99; 95% CI, 0.98-0.99), and it was lower when only the popliteal vein was involved (kappa = 0.88; 95% CI, 0.86-0.9). Also, the diagnostic accuracy of general practitioners was 95.8% (95% CI, 94.7-97), with a sensitivity of 90% (95% CI, 88.2-91.8), a specificity of 97.1% (95% CI, 96.2-98.1), a positive predictive value of 87.4% (95% CI, 85.4-89.3) and a negative predictive value of 97.8% (95% CI, 96.9-98.6) when the final diagnosis noted by the vascular physicians was the reference test.

“Our study suggests for the first time that the simple technique of compression ultrasonography may be implemented by general practitioners after adequate training,” Mumoli said. “This approach could resolve some shortage problems in geographical areas or in times of economic constraints, where the availability of a vascular physician is limited.”

Primary care physicians should consider courses organized by acknowledged scientific organizations such as American Society of Echocardiography to receive compression ultrasonography training, he added. – by Janel Miller

Disclosures: The authors report no relevant financial disclosures.

 

General practitioners trained in compression ultrasonography showed substantial accuracy and agreement, suggesting the test can be a “reliable tool” in diagnosing symptomatic proximal deep vein thrombosis, according to findings recently published in Annals of Family Medicine.

“Lower limb deep vein thrombosis represents a diagnostic dilemma for general practitioners,” Nicola Mumoli, MD, of the department of internal medicine at Ospedeale Civile di Livorno in Italy, told Healio Family Medicine. “A rapid, accurate outpatient diagnosis could improve health care quality and avoid unnecessary in-hospital evaluation.”

Physicians with 10 or more years of experience in vascular compression ultrasonography provided general practitioners with 2 months of training that consisted of 12 hours of didactic lectures, 30 hours of practice on patients and 8 hours of image review.

Mumoli and colleagues then enrolled 1,107 outpatients with suspected deep vein thrombosis in a multicenter, prospective cohort study. One of the 18 newly trained general practitioners performed the compression ultrasonography — moving the transducer distally and applying gentle compression along a patient’s deep venous system. An expert vascular ultrasonography physician conducted the same test within 2 hours. Exams with nondiagnostic or negative results were completed again 5 to 7 days later. One of the eight well-versed physicians made the definitive diagnosis. Interobserver agreement was determined.

Researchers found that agreement between the two groups of physicians was excellent, with a weighted Cohen’s kappa statistic of 0.86 (95% CI, 0.84-0.88). In addition, agreement on the diagnosis of deep vein thrombosis was almost identical when both femoral and popliteal veins were affected (kappa = 0.99; 95% CI, 0.98-0.99), and it was lower when only the popliteal vein was involved (kappa = 0.88; 95% CI, 0.86-0.9). Also, the diagnostic accuracy of general practitioners was 95.8% (95% CI, 94.7-97), with a sensitivity of 90% (95% CI, 88.2-91.8), a specificity of 97.1% (95% CI, 96.2-98.1), a positive predictive value of 87.4% (95% CI, 85.4-89.3) and a negative predictive value of 97.8% (95% CI, 96.9-98.6) when the final diagnosis noted by the vascular physicians was the reference test.

“Our study suggests for the first time that the simple technique of compression ultrasonography may be implemented by general practitioners after adequate training,” Mumoli said. “This approach could resolve some shortage problems in geographical areas or in times of economic constraints, where the availability of a vascular physician is limited.”

Primary care physicians should consider courses organized by acknowledged scientific organizations such as American Society of Echocardiography to receive compression ultrasonography training, he added. – by Janel Miller

Disclosures: The authors report no relevant financial disclosures.

 

    Perspective

    The paper by Mumoli et al is very exciting and well done. Typically, compression ultrasonography to diagnose status of the venous system in a patient’s legs is done by a vascular technician trained in the field of diagnostic vascular ultrasound and then the results are read by a certified vascular physician. However, this is a process that can take a considerable amount of time, and quick diagnoses in this condition are critical before something worse happens, such as breakage of clot going from the leg to the lung, causing the life-threatening condition of pulmonary embolisms. Physicians trained in the way described by Mumoli and colleagues will also be helpful to patients who live in remote areas where special vascular laboratories are not available or during times when these facilities might be closed. 

    The newly trained physicians in this study had an outstanding accuracy rate of deep vein thrombosis when doing their first compression ultrasonography after training. The area where there was an occasional disagreement between the newly trained physicians and the vascular-trained group was in an area behind the knee, where there are frequently problems making a diagnosis. These diagnostic and agreement rates will only get better and better as general practitioners become more versed in compression ultrasonography.

    • Daniel McCormick, DO
    • Medical director, cardiovascular product line departments of general, preventative and interventional cardiology Thomas Jefferson University and Jefferson Health, Philadelphia

    Disclosures: McCormick reports no relevant financial disclosures.