Elma J. Gussenhoven

Effect of balloon angioplasty on femoral artery evaluated with intravascular ultrasound imaging.

BackgroundIntravascular ultrasound was used to assess the immediate effect of balloon angioplasty on the superficial femoral artery. Methods and Results. In 16 consecutive patients, corresponding ultrasonic cross sections (n = 72) before and after balloon angioplasty were qualitatively and quantitatively analyzed. The qualitative data were compared with angiographic findings. Before intervention, the angiographically demonstrated obstructive lesions were confirmed by intravascular ultrasound. Ultrasound enabled discrimination between soft (n = 43) and hard (n = 29) lesions, as well as between eccentric (n = 57) and concentric (n = 15) lesions. After balloon angioplasty, the presence of a dissection assessed angiographically in 14 patients was confirmed by intravascular ultrasound. Additional morphological information provided by ultrasound included plaque rupture in 14 patients and internal lamina rupture in six patients. Quantitative ultrasound data revealed an increase in free lumen area from 9.7±4.7 to 18.3±7.0 mm2 (p ≤ 0.01), an increase in minimal lumen diameter from 2.8±0.7 to 3.6±1.2 mm (p ≤ 0.01), and an increase in media-bounded area from 21.7±5.4 to 28.3±5.8 mm2 (p ≤ 0.01). The lesion area for the majority of cases (n = 32) remained unchanged (13.0±4.9 mm2 versus 12.9±4.6 mm 2), or the lesion disappeared partially (from 9.1±0.9 to 4.3±1.4 mm2, n = 4, p.0.01) or totally (from 10.1±4.2 to 0 mm2, n = 6). Stretching of the arterial wall was further evidenced by medial thinning from 0.55±0.19 to 0.34±0.11 mm (p ≤ 0.01). ConclusionsLuminal enlargement by balloon dilatation is achieved primarily by overstretching the arterial wall, with the lesion volume remaining practically unchanged. Overstretching is accompanied almost always by dissection and plaque rupture and occasionally by an internal lamina rupture.

Accurate assessment of abdominal aortic aneurysm with intravascular ultrasound scanning: Validation with computed tomographic angiography☆☆☆★

PURPOSEnThe purpose of this study was to assess the accuracy of intravascular ultrasound (IVUS) parameters of abdominal aortic aneurysm, used for endovascular grafting, in comparison with computed tomographic angiography (CTA).nnnMETHODSnThis study was designed as a descriptive study. Between March 1997 and March 1998, 16 patients with abdominal aortic aneurysms were studied with angiography, IVUS (12.5 MHz), and CTA. The length of the aneurysm and the length and lumen diameter of the proximal and distal neck obtained with IVUS were compared with the data obtained with CTA. The measurements with IVUS were repeated by a second observer to assess the reproducibility. Tomographic IVUS images were reconstructed into a longitudinal format.nnnRESULTSnIVUS results identified 31 of 32 renal arteries and four of five accessory renal arteries. A comparison of the length measurements of the aneurysm and the proximal and distal neck obtained with IVUS and CTA revealed a correlation of 0.99 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate the length as compared with the CTA results (0.48 +/- 0.52 cm; P <.001). A comparison of the lumen diameter measurements of the proximal and distal neck derived from IVUS and CTA showed a correlation of 0.93 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate aneurysm neck diameter as compared with CTA results (0.68 +/- 1.76 mm; P =.006). Interobserver agreement of IVUS length and diameter measurements showed a good correlation (r = 1.0; P <.001), with coefficients of variation of 3% and 2%, respectively, and no significant differences (0.0 +/- 0.16 cm and 0.06 +/- 0.36 mm, respectively). The longitudinal IVUS images displayed the important vascular structures and improved the spatial insight in aneurysmal anatomy.nnnCONCLUSIONnIntravascular ultrasound scanning results provided accurate and reproducible measurements of abdominal aortic aneurysm. The longitudinal reconstruction of IVUS images provided additional knowledge on the anatomy of the aneurysm and its proximal and distal neck.

Predictors for clinical success at one year following renal artery stent placement.

Purpose: To determine pretreatment variables that may predict 1-year clinical outcome of stent placement for renal artery stenosis. Methods: In a prospective study, 40 consecutive patients (29 men; mean age 60 ± 9.1 years) with angiographically proven atherosclerotic renal artery stenosis were treated with stent placement because of drug resistant hypertension (n=14), renal function impairment (n=14), or both (n=12). Clinical success at 1 year was defined as a decrease of diastolic blood pressure ≥10 mmHg or a decrease in serum creatinine ≥20%, depending on the indication for treatment. Regression analysis was performed using anatomical parameters from angiography and intravascular ultrasound, estimates of renal blood flow from renal scintigraphy, and single-kidney renal function measurements. Results: Patients treated for hypertension had better outcome than those treated for renal function impairment, with clinical success rates of 85% and 35%, respectively. Preserved renal function, with low serum creatinine and high 2-kidney glomerular filtration rate at baseline, was associated with clinical success in the entire patient group at follow-up (p=0.02 and p=0.03, respectively). An elevated vein-to-artery renin ratio on the affected side was borderline predictive (p=0.06). In patients treated for renal impairment, lateralization to the affected kidney (affected kidney—to–2-kidney count ratio ≤0.45) on the scintigram emerged as a significant predictor for clinical success, with an odds ratio of 15 (p=0.048). Conclusions: Clinical success of renal artery stent placement is better for the treatment of hypertension than for preserving renal function. In patients with renal function impairment, lateralization to the affected kidney on the scintigram appears to be a predictor of clinical success.

Effect of Balloon Angioplasty in Femoropopliteal Arteries Assessed by Intravascular Ultrasound

OBJECTIVEnTo study the effects of balloon angioplasty (PTA) of the femoropopliteal artery with intravascular ultrasound (IVUS).nnnMATERIALS AND METHODSnCorresponding IVUS cross-sections (n = 1033) obtained before and after PTA from 115 procedures were analysed. Vascular damage including plaque rupture, dissection and media rupture was assessed. Free lumen area (FLA), media-bounded area (MBA) and plaque area (PLA) were measured.nnnRESULTSnAfter PTA vascular damage was seen at the target site in 83 (72%) arteries: plaque rupture in 30 (26%), dissection in 66 (57%) and media rupture in 20 (17%) arteries. The FLA increased from 5.4 +/- 3.4 mm2 to 14.1 +/- 5.0 mm2 (p < 0.001), MBA increased from 26.9 +/- 10.0 mm2 to 32.9 +/- 10.7 mm2 (p < 0.001) and PLA decreased from 21.6 +/- 8.5 mm2 to 18.8 +/- 8.0 mm2 (p < 0.001). The increase in MBA accounted for 68% of lumen gain. The frequency of vascular damage and the relative contribution of MBA increase and PLA decrease to luminal gain were not different in procedures with balloon diameter < or = 5 mm and > or = 6 mm.nnnCONCLUSIONSnVascular damage is common following PTA. Lumen gain is mainly due to vessel expansion and, to a lesser extent, to a decrease in plaque area.

Discrepancy between stent deployment and balloon size used assessed by intravascular ultrasound

OBJECTIVESnThis study was designed to assess the discrepancy in stent deployment seen on intravascular ultrasound and its relation to the balloon size selected for stent delivery.nnnDESIGNnProspective study.nnnMATERIALS AND METHODSnThe study group comprised 27 patients treated using a stent (n = 18) or stent-graft combination (n = 9). Following angiographically optimal stent deployment (< 10% residual stenosis) intravascular ultrasound was used to compare the smallest intra-stent lumen area with measurements at both stent edges and the lumen area of the proximal and distal reference sites.nnnRESULTSnIn 14 of the 27 stents the intra-stent dimension was the same as the dimension of the stent edge (difference < or = +/- 10%). Of the remaining stents the intra-stent dimension was smaller (difference > 10%) than the proximal stent edge in seven stents (range 11-39%), smaller than the distal stent edge in three stents (range 11-20%) and smaller than both stent edges in three stents (range 12-37%). Both in patients treated with a stent or stent-graft combination, the resulting smallest intra-stent lumen area was smaller than the balloon size used (mean difference 32% and 42%, respectively) and smaller than the mean lumen area of the reference sites (mean difference 25% and 23%, respectively).nnnCONCLUSIONnThis intravascular ultrasound study shows a discrepancy between intra-stent lumen area, the area of the stent edges and the balloon size used.

Response of renal and femoropopliteal arteries to Palmaz stent implantation assessed with intravascular ultrasound.

PURPOSEnTo establish the processes responsible for late lumen loss in renal and femoropopliteal Palmaz stents using intravascular ultrasound (IVUS).nnnMETHODSnThe first 7 consecutive patients treated with stents for renal (n = 4) and femoropopliteal (n = 3) arterial occlusive disease were studied with IVUS immediately after angiographically successful stent placement (< 10% residual stenosis) and periodically during follow-up. Images of both stent edges and the most stenotic site inside the stent at followup were matched to the same cross sections captured immediately after stent placement for quantitative analysis.nnnRESULTSnLate lumen loss in renal artery stents at 5 to 34 months was considerably less than in femoropopliteal stents (17% versus 62%, respectively). In the renal location, late lumen loss (3.0 +/- 1.3 mm2) was due to neointimal hyperplasia, whereas stent area remained unchanged (3% decrease). Late lumen loss (7.4 +/- 8.2 mm2) in femoropopliteal stents was due to neointimal hyperplasia and stent area reduction (26%). Overall, in both types of arteries, neointimal development and stent area reduction were larger at the most stenotic site than at the stent edges.nnnCONCLUSIONSnThese data suggest that there may be differences between renal and femoropopliteal arteries in the extent of hyperplastic response to stents.

Intravascular Ultrasound Evidence for Coarctation Causing Symptomatic Renal Artery Stenosis

BACKGROUNDnA recent study of human cadaveric renal arteries revealed that renal artery narrowing could be due not only to atherosclerotic plaque compensated for by adaptive remodeling, but also to hitherto undescribed focal narrowing of an otherwise normal renal arterial wall (ie, coarctation). The present study investigated whether vessel coarctation could be identified in patients with symptomatic renal artery stenosis (RAS).nnnMETHODS AND RESULTSnConsecutive symptomatic patients with angiographically proven atherosclerotic RAS who were referred for stent placement were studied by 30-MHz intravascular ultrasound before intervention (n=18) or after predilatation (n=18). Analysis included assessment of the media-bounded area and plaque area (PLA) at the most stenotic site and at a distal reference site (most distal cross-section in the main renal artery with normal appearance). Coarctation was considered present whenever the target/reference media-bounded area was </=85%. Before intervention, coarctation was observed in 9 of 18 patients and adaptive remodeling in 9 of 18 patients. Coarctation lesions had a significantly smaller PLA than adaptive remodeled lesions (P=0.001). Similarly, despite predilatation, coarctation was seen in 8 of 18 patients who had significantly smaller PLAs (P=0. 008) when compared with those patients who had adaptive remodeled lesions. No differences in severity of RAS or angiographic or clinical parameters were observed.nnnCONCLUSIONSnLow-plaque coarctation may cause a considerable proportion of symptomatic RAS, which is angiographically and clinically indistinguishable from plaque-rich RAS.

Peripheral Intravascular Ultrasonography

In recent years the development of percutaneous endovascular interventions has prompted research on new intravascular diagnostic devices; of these, intravascular ultrasound is a promising tool. Since this technique provides histologic like high resolution cross-sectional images of the artery, it is especially useful to describe morphologic characteristics of the vessel wall in conjunction with interventional techniques [1–6].