Multivariate predictors of intravascular ultrasound end points after directional coronary atherectomy

Objectives. This study attempted to identify the clinical, angiographic, procedural and intravascular ultrasound predictors of directional atherectomy results assessed by intravascular ultrasound.Background. Several angiographic and intravascular ultrasound variables have been associated with the outcome of directional coronary atherectomy. No study has incorporated both modalities into a predictive model.Methods. One hundred seventy patients were analyzed using preintervention and postintervention intravascular ultrasound and quantitative angiography. Clinical and procedural variables were collected by independent chart review. Quantitative and qualitative angiographic analysis was performed by a core laboratory in blinded manner. Intravascular ultrasound was performed using a transducer-tipped catheter, rotating within a stationary imaging sheath, and withdrawn automatically at 0.5 mm/s. Clinical, procedural, angiographic and ultrasound variables were tested iin a multivariate linear regression model. Dependent ultrasound variables included postatherectomy lumen cross-sectional area and percent cross-sectional narrowing (plaque plus media/external elastic membrane cross-sectional area) and, in a subgroup of 47 patients studied using volumetric analysis, percent plaque volume removal.Results. By multivariate stepwise linear regression analysis, predictors of residual lumen cross-sectional area (correcting for reference lumen area) included arc of calcium and preatherectomy plaque plus media cross-sectional area; predictors of residual cross-sectional narrowing were arc of calcium, preatherectomy plaque plus media cross-sectional area and lesion length; and predictors of percent plaque volume removal were arc of calcium and atherectomy device size.Conclusions. The preintervention lesion arc of calcium measured by intravascular ultrasound is the most consistent predictor of the effectiveness and results of directional coronary atherectomy.     

Stenting after directional coronary atherectomy compared with directional coronary atherectomy alone and stenting alone: a serial intravascular ultrasound study.

BACKGROUND: Directional coronary atherectomy prior to stent implantation (DCA-stent) is expected to be an effective approach to reduce restenosis. The purpose of this study was to determine whether DCA-stent has advantages over DCA alone or stenting alone using serial intravascular ultrasound (IVUS). METHODS AND RESULTS: Serial (pre-, post- and follow-up) IVUS was performed in 187 native coronary lesions treated with each of the 3 strategies. External elastic membrane cross-sectional area (CSA), lumen CSA and plaque CSA were measured. Baseline characteristics were similar. Postprocedural lumen CSA was largest after DCA-stent (11.2+/-2.7 mm2) and DCA (10.8+/-2.5 mm2) than stenting alone (9.0+/-2.9 mm2) (p<0.0005). Follow-up lumen loss was similar. As a result, follow-up lumen CSA was largest after DCA-stent (DCA-stent: 9.1+/-3.4 mm2, DCA: 7.8+/-4.2 mm2, stent: 6.3+/-2.6 mm2, p<0.0005). There was a trend toward a lower rate of restenosis with DCA-stent (DCA-stent, 12.5%; DCA, 18.3%; stent, 18.8%; p=0.57). CONCLUSIONS: DCA-stent is superior to both DCA alone and stent alone in terms of the ability to gain a larger lumen as assessed by IVUS.     

Serial volumetric (three-dimensional) intravascular ultrasound analysis of restenosis after directional coronary atherectomy

Objectives. We report the use of three-dimensional (volumetric) intravascular ultrasound (IVUS) analysis to assess serial changes after directional coronary atherectomy (DCA).

Background. Recent serial planar IVUS studies have described a decrease in external elastic membrane (EEM) area following catheter-based intervention as an important mechanism of late lumen renarrowing.

Methods. Thirty-one patients with de novo native coronary lesions treated with DCA in the Serial Ultrasound Restenosis (SURE) Trial and in Optimal Atherectomy Restenosis Study (OARS) were enrolled in this study. Serial IVUS was performed before and after intervention and at 6 months’ follow-up. In a subgroup of 18 patients from the SURE trial, IVUS was also performed at 24 h and at 1 month postintervention. Segments, 20-mm-long (200 image slices), were analyzed using a previously validated three-dimensional, computerized, automated edge-detection algorithm. The EEM, lumen, and plaque+media (P+M = EEM−lumen) volumes were calculated.

Results. At follow-up, lumen volume was smaller than at postintervention (159 ± 69 mm³ vs. 179 ± 49 mm³, p = 0.0003). From postintervention to follow-up, there was a decrease in EEM volume (377 ± 107 to 352 ± 125 mm³, p < 0.0001), but no change in P+M volume (p = 0.52). The Δ lumen volume correlated strongly with ΔEEM volume (r = 0.842, p < 0.0001), but not with ΔP+M volume. In the 18 patients from the SURE Trial, the decrease in lumen and EEM volumes occurred late, between 1 month and 6 months of follow-up.

Conclusions. Volumetric IVUS analysis demonstrated that late lumen volume loss following DCA was a result of a decrease in EEM volume. This was a late event, occurring between 1 and 6 months’ postintervention.     

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.     

Intraluminal ultrasound guidance of transverse laser coronary atherectomy

Catheter systems for laser atherectomy in peripheral and coronary arteries are subject to many design constraints. Ideal mechanical, laser and imaging requirements for these systems are proposed, and compared to the design features of a laser atherectomy system currently under development by Intra-Sonix. This system uses high resolution ultrasound for real-time guidance and control and is potentially capable of characterizing lesions and imaging critical structures in the coronary arteries, to guide physicians in the application of laser therapy. Precise catheter location and rotational direction can be provided continuously as the therapeutic intervention proceeds. Examples are given of the imaging modes and ultrasound images of an artery produced by the Intra-Sonix system.     

Relation of matrix-metalloproteinase 3 found in coronary lesion samples retrieved by directional coronary atherectomy to intravascular ultrasound observations on coronary remodeling

We investigated the relation between the presence of matrix-metalloproteinases (MMPs) and direction of remodeling in the coronary lesions of 35 patients. Positive arterial remodeling describes a compensatory expansion of the external elastic membrane (EEM) area of atherosclerotic lesions. An association between positive remodeling and unstable clinical presentation has been previously described. However, the pathophysiology of the remodeling process is not completely understood. Preinterventional intravascular ultrasound images and directional atherectomy (DCA) samples were analyzed. The remodeling ratio was calculated as the EEM area at the lesion site divided by the EEM area at the proximal reference. Positive, intermediate, and negative remodeling were defined as ratios of >1.05, 0.95 to 1.05, and <0.95, respectively. The histologic samples were immunostained for MMP-1, -2, -3, and -9. Positive, intermediate, and negative remodeling was present in 15, 7, and 13 lesions, respectively. Mild and intense cell-associated staining for MMP-1 was found in 21 (68%) and 10 (32%) patients, respectively. Staining for MMP-3 was mild in 20 patients (67%) and intense in 10 patients (33%). Immunostaining for MMP-2 and -9 was mild in all samples. Intense staining for MMP-3 was significantly more common in lesions with positive than negative and/or intermediate remodeling (58% vs 17%; P = 0.04; P = 0.053 after adjustment for gender). Thus, in this in vivo intravascular ultrasound and histologic study, increased cell-associated MMP-3 staining was associated with positive arterial remodeling.     

血管内超声指导下零对比剂行经皮冠状动脉介入治疗

目的评价血管内超声(IVUS)指导下零对比剂经皮冠状动脉介入治疗的可行性和安全性。方法入选2016年10月至2020年4月于大庆油田总医院和天津第四中心医院住院的8例冠心病患者中,在冠状动脉造影或前1次经皮冠状动脉介入治疗(PCI)时发生对比剂过敏,无法再次应用对比剂进行介入诊断和治疗者,在IVUS指导下零对比剂完成介入治疗。结果8例患者介入治疗术中未使用对比剂,参考前1次造影结果,零对比剂导引导管、导丝到位,在IVUS指导下完成病变评估、确定介入治疗部位、支架尺寸选择、置入支架后效果评估。未发生手术相关并发症,手术即刻成功率为100%。结论适当选择的对比剂过敏和严重肾功能不全患者可以在IVUS指导下零对比剂完成PCI。     

Comparison of dilatation mechanism and long-term vessel remodeling between directional coronary atherectomy and balloon angioplasty assessed by volumetric intravascular ultrasound

Although acute and late outcomes of coronary interventions have been determined by coronary angiography, this method cannot determine changes in vessel and plaque volume. Volumetric intravascular analysis has the potential to evaluate the morphology and redistribution of plaque after coronary intervention as well as longitudinal vessel remodeling. We used 3-dimensional intravascular ultrasound (3-D IVUS) to delineate the mechanism of coronary dilatation and long-term (> 1 year) remodeling in 25 patients. Ten patients underwent directional coronary atherectomy (DCA), and 15 underwent balloon angioplasty (POBA). No patients exhibited restenosis at 6-month angiographic follow-up. Validated Netra 3-D IVUS was performed pre- and post-intervention, at 6-months and at > 1-year. There were some differences in mechanism of dilatation and time course of change in vessel size between DCA and POBA patients. The principal mechanism was vessel stretching and longitudinal plaque redistribution in the POBA group and plaque debulking in the DCA group. In the POBA group, vessel volume increased just after the procedure; this increase was maintained at 6 months and at > 1-year. However, in the DCA group, vessel volume increased initially 6 months after the procedure. 3-D IVUS revealed a difference in mechanism of dilatation between POBA and DCA; this difference might affect late-term vessel remodeling even in patients without restenosis.     

The mechanism of directional coronary atherectomy

An attempt was made to assess the mechanism of directional coronaryatherectomy using different methods of analysis. Quantitativecoronary angiography was used as the gold standard to assessthe immediate results of atherectomy, and a comparative quantitativeanalysis of atherectomy and balloon angioplasty was made. Todetermine whether the post-atherectomy cross-sectional areais close to a circle, we compared the area measurements obtainedby edge detection with those obtained by videodensitometry.Finally, the extent of a ‘Dotter’ effect was establishedby quantitative angiography following crossing the stenosiswith the atherectomy device. For the purpose of this study,the results of the first 113 successful atherectomy procedureswere reviewed. In matched lesions, directional atherectomy induceda greater increase in minimal luminal diameter than balloonangioplasty (1.6 mm vs 0.8 mm; P < 0.0001 However, this luminalimprovement is due to a substantial ‘Dotter’ effectinduced by the bulky atherectomy device. Following atherectomy,only a slight difference in cross-sectional area measurementsbetween edge detection and videodensitometry (mean difference:0.28 mm² was found. Histologic examination of an atherectomizedcoronary artery showed a near-circular post atherectomy areageometry. In conclusion, directional atherectomy is a very effectivedevice with a substantially better initial result than balloonangioplasty. However, insertion of this bulky device itselfcauses an important ‘Dotter’effect.     

Impact of intravascular ultrasound guidance in patients with acute myocardial infarction undergoing percutaneous coronary intervention

Objectives: The aim of this study was to examine the utility of routine intravascular ultrasound (IVUS) guidance in patients with acute myocardial infarction (MI) undergoing percutaneous coronary intervention (PCI) with stent implantation. Background: Stent thrombosis (ST) is a serious complication of PCI with stent implantation for patients presenting with acute MI. Mechanical factors such as incomplete stent expansion and smaller stent diameters are known to correlate with ST and restenosis. IVUS guidance for stent deployment is reported to reduce these events in stable patients. Methods: We analyzed a cohort of 905 consecutive patients who underwent primary PCI for acute MI and were discharged alive. The clinical outcomes of 382 patients who underwent IVUS‐guided PCI were compared to those of 523 patients who did not. Patients who presented with cardiogenic shock and rescue PCI were excluded. The primary composite endpoint of death, MI, and target lesion revascularization at 1‐year follow‐up was systematically indexed and a propensity score was performed with regard to the use of IVUS‐guided PCI. Results: Patients undergoing IVUS‐guided PCI were older, more diabetic and hypertensive, but presented with less history of previous MI. The severity of coronary artery disease was balanced between both groups. The number of treated lesions and stents used was higher in the IVUS‐guided group, with a longer procedural duration. The overall rates of the composite primary outcome were similar (14.5% vs. 14.3%, P = 0.94) as were the rates of definite and probable stent thrombosis at 1 year (2.1% vs. 2.1%, P = 0.99) in the IVUS‐guided and no‐IVUS groups, respectively. After multivariate and propensity score adjustment, IVUS guidance was not an independent predictor for the primary endpoint. Conclusion: This study does not support the routine use of IVUS guidance for stent deployment in patients who present with acute MI and undergo primary PCI. © 2009 Wiley‐Liss, Inc.     

Restenosis after directional coronary atherectomy.

OBJECTIVES. This study evaluates the incidence of restenosis after successful directional coronary atherectomy and identifies risk factors for restenosis. BACKGROUND. Directional coronary atherectomy has been shown to be a safe and effective treatment of obstructive coronary artery disease; however, information regarding restenosis is limited. METHODS. Between October 1986 and December 1989, 289 patients with 332 lesions were successfully treated with directional coronary atherectomy and followed up prospectively. Clinical follow-up information was available for 98% and angiographic follow-up information was obtained for 82% at approximately 6 months, or earlier if symptoms recurred. Angiograms were quantitatively analyzed. Restenosis was defined as greater than 50% stenosis at the site of intervention. RESULTS. Seventy-four percent of patients were either asymptomatic or clinically improved after the procedure. Thirty-two percent were subsequently treated by coronary artery bypass surgery (14%), percutaneous transluminal coronary angioplasty (4%) or repeat atherectomy (13%). Angiographic evidence of restenosis was observed in 42%. The restenosis rate in native coronary arteries was 31% for primary lesions and 28% and 49%, respectively, for lesions treated with one or two previous angioplasty procedures. The restenosis rate for saphenous vein grafts was 53% for primary lesions and 58% and 82%, respectively, for lesions treated with one or two previous angioplasty procedures. The median interval to angiographically documented restenosis was 133 days. A higher restenosis rate was associated with a saphenous vein graft, hypertension, a longer lesion (greater than or equal to 10 mm), a smaller vessel diameter (less than 3 mm), a noncalcified lesion and use of a smaller (6F) device. CONCLUSIONS. Restenosis remains a limitation of directional coronary atherectomy. A subset of patients with larger vessels, shorter lesions or lesions treated with a larger (7F) device may have a more favorable outcome.     

Quantitative angiography after directional coronary atherectomy

OBJECTIVE--To assess by quantitative analysis the immediate angiographic results of directional coronary atherectomy. To compare the effects of successful atherectomy with those of successful balloon dilatation in a series of patients with matched lesions. DESIGN--Case series. SETTING--Tertiary referral centre. PATIENTS--62 patients in whom directional coronary atherectomy was attempted between 7 September 1989 and 31 December 1990. INTERVENTIONS--Directional coronary atherectomy. MAIN OUTCOME MEASURES--Increase in minimal luminal diameter of coronary artery segment. RESULTS--Angiographic success on the basis of intention to treat was obtained in 54 patients (87%). In four patients the lesion could not be crossed by the atherectomy device; all four had an uneventful conventional balloon angioplasty. Four of the 58 patients who underwent atherectomy were subsequently referred for coronary bypass surgery because of failure or complications; three of them sustained a transmural infarction. In the successful cases, coronary atherectomy resulted in an increase in the minimal luminal diameter from 1.1 mm to 2.5 mm with a concomitant decrease of the diameter stenosis from 62% to 22%. In the subset of 37 patients in which the changes induced were compared with conventional balloon angioplasty atherectomy increased the minimal luminal diameter more than balloon angioplasty (1.6 v 0.8 mm; p less than 0.0001). Conventional histology showed media or adventitia in 26% of the atherectomy specimens. In hospital complications occurred in six patients who had undergone a successful procedure: two transmural infarctions, two subendocardial infarctions, one transient ischaemia attack, and one death due to delayed rupture of the atherectomised vessel. All patients were clinically evaluated at one and six months. One patient had persisting angina (New York Heart Association class II), one patient sustained a myocardial infarction, one patient underwent a percutaneous transluminal coronary angioplasty for early restenosis, and one patient underwent coronary bypass surgery because of a coronary aneurysm formation. At six months 80% (36/47) of the patients were symptom free. CONCLUSIONS--Coronary atherectomy achieved a better immediate angiographic result than balloon angioplasty; however, in view of the complication rate in this preliminary series, which may be related to a learning curve, a randomised study is needed to show whether this procedure is as safe as a conventional balloon angioplasty.     

Distal embolization during directional coronary atherectomy

We report 2 cases of directional coronary atherectomy performed by using the Percu-Surge System to prevent distal embolization. A discrete amount of material was aspirated after the procedure. No clinical sequelae occurred in the immediate follow-up. These cases underline the problem of distal embolization during directional atherectomy, and the possibility to prevent it by using protection devices.     

Preintervention lesion remodelling affects operative mechanisms of balloon optimised directional coronary atherectomy procedures: a volumetric study with three dimensional intravascular ultrasound

AIMS: To classify atherosclerotic coronary lesions on the basis of adequate or inadequate compensatory vascular enlargement, and to examine changes in lumen, plaque, and vessel volumes during balloon optimised directional coronary atherectomy procedures in relation to the state of adaptive remodelling before the intervention. DESIGN: 29 lesion segments in 29 patients were examined with intravascular ultrasound before and after successful balloon optimised directional coronary atherectomy procedures, and a validated volumetric intravascular ultrasound analysis was performed off-line to assess the atherosclerotic lesion remodelling and changes in plaque and vessel volumes that occurred during the intervention. Based on the intravascular ultrasound data, lesions were classified according to whether there was inadequate (group I) or adequate (group II) compensatory enlargement. RESULTS: There was no significant difference in patient and lesion characteristics between groups I and II (n = 10 and 19), including lesion length and details of the intervention. Quantitative coronary angiographic data were similar for both groups. However, plaque and vessel volumes were significantly smaller in group I than in II. In group I, 9 (4)% (mean (SD)) of the plaque volume was ablated, while in group II 16 (11)% was ablated (p = 0.01). This difference was reflected in a lower lumen volume gain in group I than in group II (46 (18) mm(3) v 80 (49) mm(3) (p < 0.02)). CONCLUSIONS: Preintervention lesion remodelling has an impact on the operative mechanisms of balloon optimised directional coronary atherectomy procedures. Plaque ablation was found to be particularly low in lesions with inadequate compensatory vascular enlargement.     

Stent wire cutting during coronary directional atherectomy

Directional atherectomy represents one potential approach for the treatment of restenosis in stented coronary arteries. In this case report we demonstrate an important pitfall of this angioplasty technique for stent restenosis—inadvertent entanglement of the stent wire in the device. While cutting and removal of part of the wire was achieved in the case presented, this potential adverse event limits the applicability of directional atherectomy for restenosis in coronary stents.     

Clinical applications of intravascular ultrasound imaging in atherectomy

This paper discusses the potential application of intravascular ultrasound imaging in the context of catheter-based atherectomy. The advantages and limitations of ultrasound in this application are discussed, and representative cases are presented.     

Mechanisms of balloon angioplasty and directional coronary atherectomy as assessed by intracoronary ultrasound.

OBJECTIVE. This study was designed to use intracoronary ultrasound imaging to elucidate the physical effects of balloon angioplasty and directional coronary atherectomy in vivo in humans. BACKGROUND. The proposed mechanisms of coronary artery interventions such as balloon angioplasty and directional atherectomy are based on animal studies or pathologic findings and these data may not be applicable to living patients. Intracoronary ultrasound findings correlate highly with pathologic results and may allow in vivo assessment of the mechanisms of such interventions in humans. METHODS. Intracoronary ultrasound imaging was performed in 45 patients after a successful coronary intervention (balloon angioplasty in 30, directional coronary atherectomy in 15). Ultrasound images obtained at the treatment site and at an adjacent angiographically normal references site were analyzed quantitatively for minimal lumen diameter, cross-sectional lumen area, are enclosed by the internal elastic lamina, plaque area (internal elastic lamina area--lumen area) and percent area stenosis (plaque area/internal elastic lamina area). Qualitative analysis included assessment of presence of dissection, plaque composition and plaque topography. RESULTS. The results of the two procedures were similar with respect to minimal lumen diameter (angioplasty 2.6 +/- 0.5 vs. atherectomy 2.6 +/- 0.3 mm, p = NS), lumen area (0.07 +/- 0.03 vs. 0.07 +/- 0.02 cm2, p = NS) and percent area stenosis (59 +/- 14% vs. 51 +/- 21%, p = NS). However, after angioplasty, the internal elastic lamina area was significantly larger at the treated site than at the reference site (delta = +0.03 +/- 0.04 cm2, p = 0.01). There was no significant difference between the two sites after atherectomy (delta = -0.01 +/- 0.05 cm2, p = NS). In addition, dissection was seen significantly more often after balloon angioplasty than after atherectomy (50% vs. 7%, p less than 0.01). The results were similar when stratified for plaque composition and morphology. These data were confirmed in six additional patients who underwent ultrasound imaging before and after the intervention. CONCLUSIONS. Thus, the improvement in lumen dimensions after coronary balloon angioplasty is a result of both vessel stretch, demonstrated by a larger internal elastic lamina area at the treated site, and dissection. Both vessel stretch and dissection are uncommon after atherectomy, a finding consistent with plaque removal as the major mechanism for improved lumen area after this procedure.