The Accuracy of a Volume Plethysmography System as Assessed by Contrast Angiography

Background: Conventional contrast angiography (CA) is the standard diagnostic modality for peripheral artery disease of the lower extremities. However, CA presents possible risks, including contrast nephropathy and radiation exposure. An invasive procedure, it is not chosen to evaluate non-invasive physiologic procedures testing for vascular disease. Alternatively, Duplex ultrasonography (Duplex) is used to assess other non-invasive procedures that evaluate the presence or extent of peripheral artery disease. However, Duplex is not an infallible tool. Rather, another non-invasive physiologic test for peripheral artery disease is a volume plethysmography system (VPS), a blood volume waveform visualization and evaluation tool.

Objective: To determine the accuracy of a VPS as an aid for the primary care physician to more accurately identify patients with peripheral artery disease who might benefit from preventive management.

Design: Retrospective case series and a case presentation. Patients: Community vascular laboratory group consisting of 48 patients.

Methods and Findings: Patients were tested bilaterally with a VPS on all four limbs as per standard testing protocol. They subsequently underwent peripheral CA due to symptoms, physical examination, VPS or Duplex results suggestive of significant peripheral artery disease. Using CA as the gold standard for determining peripheral artery disease, the VPS had sensitivity of 86.0%, specificity of 100% and accuracy of 87.5%. Results indicated flow obstruction in 37 of 48 patients and showed no flow obstruction in 11 of 48 patients. The CA results confirmed peripheral artery disease in 37 of 37 patients with suspected peripheral artery disease by the VPS result.

Conclusion: Accuracy of the VPS is verified by CA results, supporting its use as an aid for practicing physicians to accurately diagnose peripheral artery disease. VPS is intended to provide primary care physicians with a tool, which in combination with clinical judgment, to more accurately identify patients with peripheral artery disease who might benefit from preventive management. When appropriate, patients may be referred to a vascular specialist.


Andrew Gomes

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