Original contribution
Comparison of angiography, duplex sonography and intravascular ultrasound for the graduation of femoropopliteal stenoses before and after balloon angioplasty

https://doi.org/10.1016/j.ultrasmedbio.2006.06.015Get rights and content

Abstract—

The graduation of femoropopliteal stenoses by either digital subtraction angiography (DSA) or duplex sonography remains challenging, particularly after percutaneous transluminal angioplasty (PTA). More accurate assessment of stenosis might be achieved with intravascular ultrasound (IVUS). We investigated the relationship between DSA, IVUS and duplex before and after 32 femoropopliteal PTAs. Over the whole range of stenoses, peak systolic velocity (PSV) and peak velocity ratio (PVR) correlated better with DSA-stenosis (R2 = .72 and 0.74, respectively, p < 0.01) than with IVUS-stenosis (R2 = 0.58 and 0.50, p < 0.01). Within the subgroup of preinterventional (51 to 99%) stenoses, PVR was significantly correlated only with DSA-stenosis (R2 = 0.60, p < 0.01). Severe dissection after PTA was associated with a disproportionate rise in PSV and large discrepancies between IVUS and DSA. Unexpectedly, our data show that intrastenotic flow acceleration assessed by duplex sonography correlates better with DSA- than with IVUS-stenosis. The concordance between duplex sonography, DSA and IVUS was particularly weak in postinterventional measurements, casting some doubt on the reliability of these methods for the assessment of residual stenosis after femoropopliteal PTA. (E-mail: [email protected])

Introduction

Duplex sonography is widely accepted for the noninvasive diagnosis of lower-limb peripheral arterial disease (PAD). Assessment of arterial stenoses by duplex sonography is based on the measurement of intrastenotic flow acceleration. Duplex-sonographic algorithms have generally been validated by comparison with digital subtraction angiography (DSA). These studies have shown a high sensitivity and specificity of duplex sonography for the detection of hemodynamically significant stenosis causing a diameter reduction above 50%. However, most investigators agree that a more detailed quantification of stenoses by duplex sonography is not reliable (Kohler et al., 1987, Leng et al., 1993, Moneta et al., 1992, Moneta et al., 1993, Ranke et al., 1992).

Hemodynamic changes induced by an arterial stenosis are expected directly to be related to the reduction in lumen area. The relationship between the diameter stenosis seen on angiography and the corresponding reduction in lumen area depends on the geometry of the stenosis, which can be difficult to estimate from the 2-D angiographic view. Therefore, angiography may be an inaccurate measure of the degree of intrastenotic area reduction, particularly in severely arteriosclerotic arteries with diffuse, irregular stenoses and a high degree of calcification (De Scheerder et al. 1994).

The quantification of stenosis becomes even more complicated after percutaneous transluminal angioplasty (PTA). PTA is known to cause tears and dissections of the arterial wall in more than 70% of cases (plaque rupture in 26%, dissections in 57% and media rupture in 17%) (van der Lugt 1997). DSA may be unreliable for the quantification of the degree of dissection and residual stenosis after PTA (Tetteroo et al., 1996, Van Lankeren et al., 1998). Disturbances in blood flow due to intimal flaps and dissections may also impair the interpretation of duplex-sonography. Accordingly, previous studies have shown that duplex-sonographic measurements after PTA do not correlate with the angiographic residual stenosis (Mewissen et al., 1992, Sacks et al., 1990) or the intraarterial pressure gradient (De Smet et al. 2000).

Intravascular ultrasound (IVUS) allows the direct measurement of lumen area as well as accurate visualization of dissections and tears after angioplasty. Therefore, IVUS may be a better “gold standard” for the quantification of arterial stenoses than DSA. IVUS has been widely used during coronary interventions (Fuessl et al., 1999, Nissen and Yock, 2001), whereas there is only limited experience in the femoropopliteal region (Gerritsen et al., 1993, Gussenhoven et al., 1995, Pasterkamp et al., 1996, The et al., 1992; Van der Lugt et al., 1997, Van Lankeren et al., 1998, Vogt et al., 1997). The aim of the current study was to compare the performance of IVUS, DSA and duplex sonography for quantification of femoropopliteal stenoses before and after femoropopliteal PTA.

Section snippets

Patients

Thirty patients (23 men, seven women) were studied before and after PTA of the superficial femoral or popliteal artery. A total of 32 studies were performed (two patients had bilateral PTA on separate occasions). The clinical indication for PTA was disabling claudication, ischemic rest pain or ischemic lesions (Fontaine stages II, III and IV). All patients were selected based on the results of preinterventional duplex sonography, which had to show hemodynamically significant femoropopliteal

Results

Primary technical success of PTA was achieved in all patients. The postinterventional perfusion of the target leg (assessed by physical examination, pulse volume recordings and ABI) was improved after 19 (59.4% partial success) and normalized after 13 procedures (40.6% total success). Mean ABI improved significantly from 0.69 to 0.92 (Table 1).

Mean values and ranges for DSA diameter stenosis, IVUS area stenosis, duplex PSV and PVR before and after PTA are shown in Table 1. The degrees of

Discussion

The current study was designed under the assumption that direct determination of the intrastenotic area reduction by IVUS might provide a more exact measure of the degree of arterial stenosis than 2-D diameter measurements obtained by DSA. If this assumption were true, one would expect hemodynamic duplex measurements to correlate more closely with the degree of stenosis measured by IVUS than by DSA. However, our data turned out to show exactly the opposite. Duplex sonographic PSV and

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