Cath Lab Digest

Author:

¹Ali Morshedi-Meibodi, MD, ²Theodore A. Tan, MD, ³Aravinda Nanjundappa, MD, RVT, ¹Robert S. Dieter, MD, RVT

Author Affiliations:

From ¹Loyola University, Maywood, Illinois, ²Charleston Area Medical Center and ³West Virginia University, Charleston, West Virginia.

Correspondence: Robert S. Dieter, MD, RVT, Assistant Professor of Medicine, Vascular and Endovascular Medicine, Interventional Cardiology, Loyola University, 2160 S. First Ave., Maywood, IL 60153. E-mail: rdieter@lumc.edu.

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In the past decade, diagnostic technology has made advances in leaps and bounds. As can be seen in the systematic review of previous studies by Koshy et al1, the sensitivity and specificity of an arterial duplex study and color flow imaging has increased significantly, making it a highly effective tool for non-invasive evaluation of peripheral arterial disease (PAD).

Current arterial duplex modalities offer significantly better anatomic evaluation for lesions in PAD patients. The current article compares the sensitivity and specificity of arterial duplex study with digital subtraction angiography (DSA). Their results are generally comparable to a similar study by Favaretto et al in 2007,2 where good concordances were found between arterial duplex studies and DSA in aorto-iliac and femoro-popliteal disease, and fair to poor concordances in popliteal and infrapopliteal disease.3–6 The advances in Doppler ultrasound technology, such as power Doppler, have increased the sensitivity and specificity of the studies. Some basic limitations have obviously not yet been overcome, especially for duplex imaging studies below the knee.4–6

The practical advantages of one imaging modality over another are no longer clear-cut. The choice is no longer limited to just accuracy in the clinical setting. The improvements in accuracy have been such that magnetic resonance angiography (MRA), computed tomography angiogram (CTA), or even Doppler ultrasound can often match DSA, the gold standard in PAD. In an assessment of health technology by Collins et al,6 intravascular contrast angiography and MRA equally show the best accuracy for detecting PAD in the whole leg, compared to CTA and ultrasound. From a patient preference standpoint, Doppler ultrasound, MRA, and CTA are most preferred by patients over the more invasive contrast angiography. From an economic standpoint, Doppler ultrasound was obviously found to be the most economical for whole leg assessment with higher effectiveness at lower cost, despite its limitations, which include body habitus and below knee evaluations. For leg section studies, MRA is the most cost-effective modality.5,7 Sometimes the choice of imaging is influenced by other factors. For patients with known contrast allergies, an ultrasound is evidently the first choice. Painful extremities in acute and critical limb ischemia will present difficulties in patient cooperation for Doppler ultrasound. Often it is not a matter of which modality is better, but rather what’s available with accurate findings.

The authors have highlighted the increasing variety of accurate diagnostic tools available to clinicians today. What we have to remember is that these tools need not necessarily be competitive with each other and may be better applied in complement with each other for both diagnostic, pre-op planning, and confirmatory purposes.