IVUS Guidance Research Articles

Intravascular Ultrasound Versus Angiography-Guided Drug-Eluting Stent Implantation: The ULTIMATE Trial

BackgroundIntravascular ultrasound (IVUS)-guided drug-eluting stent (DES) implantation is associated with fewer major adverse cardiovascular events compared with angiography guidance for patients with individual lesion subset. However, the beneficial effect on major adverse cardiovascular event outcome of IVUS guidance over angiography guidance in all-comers who undergo DES implantation still remains understudied. ObjectivesThis study aimed to determine the benefits of IVUS guidance over angiography guidance during DES implantation in all-comer patients. MethodsA total of 1,448 all-comer patients who required DES implantation were randomly assigned (1:1 ratio) to either an IVUS guidance or angiography guidance group. The primary endpoint was target-vessel failure (TVF) at 12 months, including cardiac death, target-vessel myocardial infarction, and clinically driven target-vessel revascularization (TVR). The procedure was defined as a success if all IVUS-defined optimal criteria were met. ResultsAt 12 months follow-up, 60 TVFs (4.2%) occurred, with 21 (2.9%) in the IVUS group and 39 (5.4%) in the angiography group (hazard ratio [HR]: 0.530; 95% confidence interval [CI]: 0.312 to 0.901; p = 0.019). In the IVUS group, TVF was recorded in 1.6% of patients with successful procedures, compared with 4.4% in patients who failed to achieve all optimal criteria (HR: 0.349; 95% CI: 0.135 to 0.898; p = 0.029). The significant reduction of clinically driven target-lesion revascularization or definite stent thrombosis (HR: 0.407; 95% CI: 0.188 to 0.880; p = 0.018) based on lesion-level analysis by IVUS guidance was not achieved when the patient-level analysis was performed. ConclusionsThe present study demonstrates that IVUS-guided DES implantation significantly improved clinical outcome in all-comers, particularly for patients who had an IVUS-defined optimal procedure, compared with angiography guidance. (Intravascular Ultrasound Guided Drug Eluting Stents Implantation in “All-Comers” Coronary Lesions [ULTIMATE]; NCT02215915)

Intraluminal Intensity of Blood Speckle on Intravascular Ultrasound, a Novel Predictor of Periprocedural Myocardial Injury After Coronary Stenting

The difference in the intraluminal intensity of blood speckle (IBS) on integrated backscatter-intravascular ultrasound (IB-IVUS) across a coronary artery stenosis (i.e., ΔIBS) has previously shown a negative correlation with fractional flow reserve, reflecting an impaired coronary blood flow. Periprocedural myocardial injury (PMI) after coronary stenting has also been associated with coronary circulatory dysfunction. The aim of this study was to investigate the relation between ΔIBS after coronary stenting and PMI. A total of 180 patients who underwent elective coronary stenting under IVUS guidance for a single lesion were included. Intraluminal IBS was measured using IB-IVUS in cross sections at the ostium of the target vessel and at the distal reference of the stent. ΔIBS was calculated as (distal IBS value) - (ostium IBS value). PMI was defined as an elevation of troponin I >5 times the 99th percentile upper reference limit (>0.45 ng/ml) within 24 hours after the procedure. The mean ΔIBS after coronary stenting was 6.52 ± 5.71. There was a significantly greater use of the rotational atherectomy, the number of stents, the total stent length, and ΔIBS in patients with PMI than those without. In the receiver operating characteristic curve analysis, ΔIBS significantly predicted PMI (area under the curve 0.64, best cut-off value 7.88, p = 0.001). Multiple logistic regression analysis determined that the total stent length, the use of rotational atherectomy, and ΔIBS were independent predictors of PMI. In conclusion, greater ΔIBS assessed by IB-IVUS was significantly associated with PMI after coronary stenting in patients with a stable coronary artery disease.

Intravascular ultrasound guidance of percutaneous coronary intervention in ostial chronic total occlusions: a description of the technique and procedural results.

Inability to cross the lesion with a guidewire is the most common reason for failure in percutaneous revascularization (PCI) of chronic total occlusions (CTOs). An ostial or stumpless CTO is an acknowledged challenge for CTO recanalization due to difficulty in successful wiring. IVUS imaging provides the opportunity to visualize the occluded vessel and to aid guidewire advancement. We review the value of this technique in a single-centre experience of CTO PCI. This series involves 22 patients who underwent CTO-PCI using IVUS guidance for stumpless CTO wiring at our institution. CTO operators with extensive IVUS experience in non-CTO cases carried out all procedures. Procedural and outcome data was prospectively entered into the institutional database and a retrospective analysis of clinical, angiographic and technical data performed. 17 (77%) of the 22 procedures were successful. The mean age was 59.8 ± 11.5years, and 90.9% were male. The most commonly attempted lesions were located in the left anterior descending 36.4% (Soon et al. in J Intervent Cardiol 20(5):359-366, 2007) and Circumflex artery (LCx) 31.8% (Mollet et al. in Am J Cardiol 95(2):240-243, 2005). Mean JCTO score was 3.09 ± 0.75 (3.06 ± 0.68, 3.17 ± 0.98 in the successful and failed groups respectively p = 0.35). The mean contrast volume was 378.7ml ± 114.7 (389.9ml ± 130.5, 349.2ml ± 52.2 p = 0.3 in the successful and failed groups respectively). There was no death, coronary artery bypass grafting or myocardial infarction requiring intervention in this series. When the success rates were analyzed taking into account the date of adoption of this technique, the learning curve had no significant impact on CTO-PCI success. This series describes a good success rate in IVUS guided stumpless wiring of CTOs in consecutive patients with this complex anatomical scenario.

45 Intravascular ultrasound guidance of percutaneous coronary interventions in ostial chronic total occlusions

Background Inability to cross the lesion with a guidewire is the most common reason for failure in percutaneous revascularisation (PCI) of chronic total occlusions (CTOs). An ostial or stumpless CTO is an acknowledged challenge for CTO recanalisation due to difficulty in successful wiring. IVUS imaging provides the opportunity to visualise the occluded vessel and to aid guidewire advancement. We review the value of this technique in a single-centre experience of CTO PCI. Methods This series involves 22 patients who underwent CTO-PCI using IVUS guidance for stumpless CTO wiring at our institution. CTO operators with extensive IVUS experience in non-CTO cases carried out all procedures. Procedural and outcome data in this population was prospectively entered into the institutional database and a retrospective analysis of clinical, angiographic and technical data was performed. Results 17 (77%) of the 22 procedures were successful. The mean age was 59.8 ± 11.5 years, and 90.9% were male. The most commonly attempted lesions were located in the Left Anterior Descending (LAD) 36.4% (8) and Circumflex artery (LCx) 31.8% (7). Mean JCTO score was 3.09 ± 0.75 (3.06 ± 0.68, 3.17 ± 0.98 in the successful and failed groups respectively p = 0.35). The mean contrast volume was 378.7 ml ± 114.7 (389.9 ml ± 130.5, 349.2 ml ± 52.2 p = 0.3 in the successful and failed groups respectively). There was no death, coronary artery bypass grafting or myocardial infarction requiring intervention in this series. When the success rates were analysed taking into account the date of adoption of this technique, the learning curve had no significant impact on CTO-PCI success. Conclusions This series describes a good success rate in IVUS guided stumpless wiring of CTOs in consecutive patients with this complex anatomical scenario.

Deep Venous Thrombosis Associated With Caval Extension of Iliac Stent

It is generally difficult to place an iliac vein stent “precisely” at the iliac caval junction with venographic control or even with IVUS guidance. This is because the anatomic junction is not circular but a tilted oval and the lesion whether primary or post-thrombotic may variably encroach on the vena cava. We have advocated extending the stent 3 to 5 cm into the cava to prevent the lesion squeezing the stent distally or compressing the end into a cone. This suggestion has met with resistance due to concerns of jailing contralateral iliac flow and subsequent deep venous thrombosis (DVT). We analyzed DVT incidence following placement of Wallstent with caval extension as well as a modification where a Z stent on top of the Wallstent stack was used for the extension. With widely spaced struts, contralateral jailing was less likely to occur in addition to other technical benefits. A total of 755 limbs with consecutive Wallstent caval extensions (2007 to 2011) and 982 limbs with Z stent extensions (2011 to 2015) were analyzed for DVT incidence. Fisher exact test was used for statistical comparison. Patient demographics were similar for both groups. The mean age was 58 years old; 68% female and 32% male; 61% of patients left side, and 39% right side. Patient pathology: 52% PTS only, 35% MTS only, 13% had both MTS and PTS. DVT incidence is shown in the Table. Left sided DVT was more common overall and in either group (P < .003). DVT incidence overall, ipsilateral DVT, and contralateral DVT were all significantly lower with the Z stent modification. (P < .0001). In addition, the Z stent modification provides greater radial strength at the iliac-caval choke point and enormously simplifies simultaneous or sequential bilateral stenting.TableComparison of DVT incidence among Wall-stent and Z-stent patientsContralateral DVT (<30 days)Contralateral DVT (≥30 days)Total Contralateral DVTsIpsilateral DVT (<30 days)Ipsilateral DVT (≥30 days)Total Ipsilateral DVTsTotal DVTsWall-stent (n = 755)5141926123857Z-stent (n = 982)21***3***6***3**9***12***NS (>0.05), * (<0.05), ** (<0.01), *** (<0.001). Open table in a new tab

TCTAP A-077 IVUS Guided Minimum Contrast PCI for CKD Patients

Estimated safety dose of contrast media for chronic kidney disease(CKD) patients is computed by the following formula,bodyweight x5/Serum creatinine(SCr). To reduce the account of contrast media, IVUS guidance throughout the procedure, would be effective. To clarify the efficacy of IVUS guided

Intravascular Ultrasound–Guided Percutaneous Coronary Interventions

Coronary angiography falls short in accurately delineating the anatomy of epicardial vessels because it provides only a 2-dimensional visualization of the lumen.1 Moreover, angiographic lesion assessment is impeded in cases of diffuse disease of reference vessels, lesion foreshortening, and eccentricity, and the overlap of several arterial branches, as well. Conversely, intravascular ultrasound—a sound wave–based technology—provides superior spatial resolution of 80 to 150 μm and extends diagnostic information, enabling more precise assessment of lumen and vessel wall dimensions including atheroma burden and vessel remodeling. Article see p 463 Intravascular ultrasound (IVUS) has been proposed for the assessment of lesion severity in cases of intermediate left main and non–left main lesions. In addition, IVUS has been used to guide percutaneous coronary interventions (PCI) by informing the operator of reference vessel dimensions, lesion length, and extent of calcification to plan the procedure. Finally, IVUS has been implemented to optimize stent deployment, and criteria have been developed such as the Multicenter Ultrasound Guided Stent Implantation (MUSIC)2 and Angiography versus IVUS Optimization (AVIO)3 criteria to this effect. During the bare metal stent era, IVUS guidance was reported to reduce the risk of restenosis and repeat revascularization.4 In contrast, the use of IVUS after drug-eluting stent (DES) implantation failed to improve clinical efficacy with IVUS guidance despite larger stent dimensions at the end of the procedure. Notwithstanding, some studies suggested a lower risk of stent thrombosis with IVUS-guided DES implantation owing to the detection of mechanical factors associated with stent thrombosis, including edge dissections, stent malapposition, and stent underexpansion.5 More recently, the propensity score–matched comparison of IVUS guided with angiography-guided PCI of unprotected left main lesions (MAIN-COMPARE)6 reported lower mortality, with IVUS guidance potentially related to a lower risk of sudden death and stent thrombosis. Current American College of Cardiology …

Transradial retrograde approach rescuing iatrogenic long spiral dissection during chronic total occlusion intervention

Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) is one of the greatest challenges in coronary interventions. A retrograde approach via the collateral channel has been recently proposed to improve the success rate of PCI in CTO lesions of the coronary arteries. We describe an accidental complication encountered during transradial PCI to recanalize right coronary artery CTO in a patient with unstable angina. A long spiral dissection has been created by antegrade wiring and extended from the ostium all the way down to mid RCA segment. Subsequent attempts with antegrade wiring into the true lumen were unsuccessful. Ad-hoc retrograde recanalization has been employed to rescue the vessel via septal collateral from left anterior descending artery. Retrograde wiring and dilatation were performed followed by successful antegrade wiring into the true lumen under IVUS guidance, which revealed significant intramural hematoma extending distally to the posterolateral branch. Bailout stenting was achieved with sealing of the multiple entry and exit sites created by the spiral dissection and complete coverage of the intramural hematoma. This report highlights the role of the retrograde approach as a rescue option in the setting of complicated antegrade approach and to improve the success rate of CTO-PCI. Moreover, IVUS was a valuable tool to confirm the true lumen course of the successful wire and to guide the stenting procedure.

TCT-68 Does IVUS Reduce Stent Thrombosis with DES? Two-year results from the prospective, multicenter ADAPT-DES study

Whether IVUS guidance reduces the long-term rates of stent thrombosis (ST) after drug-eluting stent (DES) implantation is controversial. ADAPT-DES was a prospective, multicenter, real-world registry of 8,583 pts at 11 international centers undergoing percutaneous coronary intervention (PCI) with

Clinical characteristics, procedural and clinical outcome of patients treated with PCI for definitive stent thrombosis: a 12 years single centre experience

Background: There are limited data on treatment and long-term clinical outcome after definitive (angiographically confirmed) stent thrombosis (ST). Methods: Retrospective analysis of baseline characteristics and procedural and clinical outcomes in patients with angiographically confirmed ST (ARC classification) from a cohort of 8069 consecutive unselected patients treated by PCI in a single centre (June 2000-December 2012). Results: One hundred thirty consecutive patients with definite ST were included in the analysis (1.6%). a) Main baseline characteristics: male sex 82.3%; age 63±13; diabetes 38.5%; previous renal failure 23.1%; previous AMI 69.2%, peripheral arterial disease (PAD) 16.6%. Clinical presentation was ST-segment elevation myocardial infarction in 68% and cardiogenic shock in 13%. Mean time from stent implantation to ST was 636±1168 days. According to ARC classification, 14.6% were acute; 35.4% subacute; 14.6% late and 35.4% very late. Previous implanted stent was DES in 39.2%. b) Main procedural characteristics: IIbIIIa inhibitors were used in 66.2%; IVUS guidance in 44.6%; manual thrombectomy in 70.8%; new stent implantation in 74.6%. c) Main clinical outcomes: in-hospital mortality was 9.2% and one-year mortality was 12.3%. Two patients (1.5%) experienced recurrent ST on follow-up. Type of previously implanted stent (DES or BMS), time of ST (acute, subacute, late or very late), vessel treated and DES implantation for ST treatment were not related to mortality on follow-up. Independent predictors for one-year mortality were age, PAD, cardiogenic shock on admission and multivessel disease. Conclusion: In a cohort of real-life consecutive patients, PCI for ST was relatively infrequent. Patients presenting with ST had high comorbidity levels. Up to one third of patients had very late ST. Nearly half of the PCI were IVUS-guided. One-year mortality and recurrent ST on follow-up was lower than previously reported; this may be explained by the high rate of IVUS-guided PCI.

Spontaneous disappearance of coronary pseudoaneurysm due to coronary artery perforation following percutaneous coronary intervention

In recent years, while therapeutic outcome after percutaneous coronary intervention is improving due to the introduction of drug-eluting stent and device development, procedure-related complications including coronary perforation may ineluctably occur though at low-frequency, even if careful manipulations are performed under IVUS guidance. Meanwhile, coronary pseudoaneurysm subsequent to coronary perforation is one of the complications at chronic phase infrequently experienced following percutaneous coronary intervention. To date, the incidence and natural history of pseudoaneurysm following coronary artery perforation remain unclear. We experienced a case with coronary pseudoaneurysm developed 2 weeks after Ellis II-type coronary artery perforation which spontaneously disappeared 4 months later. As the mechanism of disappearance, thrombotic occlusion was confirmed upon intravascular ultrasound.

Impact of intravascular ultrasound guidance in routine percutaneous coronary intervention for conventional lesions: data from the EXCELLENT trial

BackgroundIntravascular ultrasound (IVUS) offers tomographic images of coronary artery, helping physicians refine percutaneous coronary intervention (PCI) procedures. However, it is still controversial whether routine use of IVUS in conventional lesions leads to improvement in clinical outcomes after PCI. MethodsFrom the EXCELLENT trial, patients were grouped into IVUS-guided versus IVUS-non-guided PCI (619 and 802 patients, respectively). The crude patients as well as the propensity score matched pairs were compared with regard to clinical outcomes. ResultsBaseline characteristics showed younger age and lower incidence of comorbidities in the IVUS group. IVUS-guided PCI was associated with more aggressive treatment such as longer stenting length, larger stent diameter, and greater number of stents implanted. In the total population, IVUS guidance was associated with a significantly higher risk of periprocedural MI with no significant differences in other outcomes. In the matched cohort (463 matched pairs, 926 patients), IVUS guidance was associated with significantly increased risk of target lesion failure (4.3% vs. 2.4%; p=0.047 by conditional logistic regression) and major adverse cardiovascular events at 1year almost exclusively due to increased risk of periprocedural myocardial infarction (MI) (1.6% vs. 0.2%; p=0.050), while the rates of cardiac death, spontaneous MI, and target lesion revascularization did not differ significantly between the two groups. ConclusionsThe adjunctive use of IVUS during PCI was associated with more stents implanted, longer stenting, and bigger stenting. There were no significant advantages of IVUS guidance, but rather a significant increase in periprocedural enzyme elevation, reflecting more aggressive procedures performed with IVUS guidance.

IVUS guidance in percutaneous closure of aortic paraprosthetic leak

Severe aortic regurgitation due to paraprosthetic leak appears in 1-5% of patients with previous aortic valve replacement. Surgical management is the treatment of choice but has high morbidity and mortality and leak recurrence is not uncommon. Different approaches to percutaneous closure have been tried. Transesophageal echocardiography (TEE) is a key factor to measure and localize leakages. Performing TEE during the procedure implies general anesthesia and prolongs procedure and fluoroscopy times. We report the case of an aortic paraprosthetic leak percutaneous closure using intravascular ultrasound to guide the procedure.

Relationship Between Restenosis and Over-aggressive Stent Expansion in Non-complex PCI Without IVUS Guidance

Relationship Between Restenosis and Over-aggressive Stent Expansion in Non-complex PCI Without IVUS Guidance

Successful use of the five‐in‐six system with IVUS guided transradial renal artery stenting

In transradial renal intervention, the long distance between the vascular access and the target lesion represents a major issue. The 100 cm guiding catheter (GC) may be too short to engage the renal artery particularly in tall patients or with excessive aortic turtousity. On the other hand, with the use of 125 cm long GC, only few premounted dedicated renal stents can be used. The shaft of the stent delivery system must be 140 cm or more to be compatible with the 125 GC. However, in many renal interventions, only few more centimeters are required to give the GC the sufficient working length needed for proper engagement and back up support. For this purpose, we used the Terumo "five-in-six" system to provide the necessary extra length through the protruding part of the 5 Fr GC out of the tip of the 6 Fr GC. With the super soft distal segment of the 5 FR GC deeply intubated into the right renal artery, we had the sufficient backup support to do renal stenting with IVUS guidance. This case illustrates that the "five-in-six" system can be an alternative strategy whenever extra length or strong backup support is needed during transradial renal artery intervention.

Does Troponin Elevation After Percutaneous Coronary Intervention Really Represent Myocardial Infarction? Insights from a Biomarker and MRI Study of Complex PCI

Background: Although optimum stent deployment mandates adequate stent expansion and strut apposition, there is growing concern that stent distortion and strut fracture may predispose to late adverse cardiac events including restenosis and even stent thrombosis. The potential for this procedural risk factor for restenosis is conceivably greater when stents are over-stretched or expanded in interventional labs in which IVUS guidance is not routine. Purpose: We therefore investigated how frequently undersized stents are selected and subsequently “overexpanded” in a real-world all-comers setting, andwhether the degree of “mismatch” between nominal stent size and final stent size correlates with the degree of restenosis. Methods: We studied 160 patients (mean age 58 range 35–80; 36% diabetic; 21% female) undergoing singlevessel stenting for de novo stenosis. A single stent was deployed in 140 patients (88%), 2 in 17 patients, 3 in 2 patients and 4 in 1 patient. Mean total stent length was 21mm (8–91). Drug-eluting stents (DES) were used in 51 patients (32%), bare-metal stents (BMS) in 109. All patientshadundergone ischaemia-driven repeat coronary angiography between 12 and 24 months after the index procedure. Results: Only 39 patients (24%) received a stent with nominal size ≤ 2.75mm. The final stent size was ≥3.0mm in 120 patients (75%) and ≥3.5mm in 63 (39%). In these highly selected patients undergoing ischaemia-driven repeat coronary angiography, 50 (31%) had angiographic in-stent restenosis ≥50%. There was no correlation between stent size “mismatch” and % angiographic in-segment stenosis across the whole group (n= 160; R2 =−0.0152), in those with final stent size ≤2.75mm (R2 =−0.0642), in those with final stent size ≥3.0mm (R2 =−0.0148), in those with final stent size ≥3.5 (R2 = 0), in those with BMS (R2 =−0.0041) or DES (R2 =−0.0287), and in those with angiographic in-stent restenosis (R2 =−0.0005). Furthermore, thedegreeof “mismatch” was similar in patients with and without binary restenosis (0.34 vs. 0.41mm; 2P= 0.097). In the BMS subgroup (n= 109), therewasalsonocorrelationbetweenstent size “mismatch” and % angiographic in-segment stenosis in thosewithfinal stent size≥3.0mm(R2 =−0.0033) or≥3.5 (R2 = 0.0064). Conclusions: In this highly selected real-world population treatedatanestablished interventional centrewithout routine IVUS guidance, there is little evidence of systematic use of stents that are undersized. Furthermore, any stent “over-expansion” – as reflected by the “mismatch” between nominal and final stent size – did not predispose at all to restenosis, and so is unlikely to be a major procedural driver of restenosis.

Abstract 3350: Long-Term Outcomes After Drug-Eluting Stenting of Bifurcation Lesions With the Simultaneous Kissing Stents (SKS) Technique

Percutaneous coronary interventions (PCI) of bifurcation lesions using simultaneous kissing stents (SKS) technique have shown to have good short-term and mid-term results. Limited data are available regarding long-term outcome with this strategy. Methods: We analyzed the long-term outcome of 300 consecutive patients treated with drug-eluting stenting using SKS technique for 305 de novo bifurcation lesions. Cypher stents were used in 265 lesions and Taxus stents were used in 40 lesions, from May 2003 to September 2006 at Mount Sinai Hospital. Clinical follow-up was obtained in 98.6%. All pts were given Aspirin and Plavix 75 mg daily for one year and GP IIb/IIIa inhibitors were used in 72% of cases. Results: Overall procedural success was 99% for main vessel (MV) and 98% for side-branch (SB), with one case of intra-procedural stent thrombosis of left main bifurcation. 30-day MACE (MI, death, repeat target vascularization or stent thrombosis) occurred in 5% of cases. Long-term follow-up results at a mean of 14 ± 5 months are shown in the Table . Overall incidence of stent thrombosis was 1.7% (1.5% for Cypher vs. 2.5% for Taxus). Multivariate predictors of TVR were left main (LM) intervention (odds ratio [OR] 4.97; 95% confidence interval [CI] 2.00 to 12.37, p = 0.01) and diabetes mellitus (OR 4.21; 95% CI 1.15 to 18.56, p = 0.04) and of follow-up MACE were LM intervention (OR 3.79; 95% CI 1.76 to 8.14, p = 0.01) and acute MI (OR 3.24; 95% CI 0.95 to 15.32, p = 0.02). Conclusions: The SKS technique for bifurcation lesions using Cypher or Taxus DES is associated with long-term favorable outcomes in this complex, high-risk PCI group. Delayed stent thrombosis with dual antiplatelet therapy remains within acceptable limits. Further work is needed to lower the event rates in some specific subgroups such as LM lesions and AMI settings (perhaps by IVUS guidance and Plavix 75 mg twice a day).

The importance of IVUS guidance during contemporary percutaneous coronary intervention with drug-eluting stents for the prevention of stent thrombosis

The importance of IVUS guidance during contemporary percutaneous coronary intervention with drug-eluting stents for the prevention of stent thrombosis

Stent Thrombosis after Successful Drug-Eluting Stent Implantation

Background and Objectives:Stent thrombosis (ST) after a successful drug-eluting stent (DES) implantation has been reported in around 1% of clinical trials. However, the incidence of ST with a DES in practice is not well known. Here, we evaluated the possible causes of ST encountered in four Korean hospitals. Subjects and Methods:Between March 2003 and December 2003, 450 patients were treated using a DES in the four study hospitals. We reviewed the clinical and procedural characteristics of 8 patients that experienced ST after a successful DES implantation. Results:Eight patients (1.8%), who were administered antiplatelet medication, experienced ST, with a mortality of 50% at the 2 month follow-up. ST occurred within 7 days in all patients, with the exception of one, with an occurrence 37 days after intervention. Initially, all patients were diagnosed as having acute coronary syndrome. Direct PTCA was performed in 3 patients (38%). Severe calcification or a thrombus was noted in 6 (67%) of 9 lesions. In all cases, no GPIIbIIIa inhibitors were used prior to the DES implantation. Incomplete lesion coverage and incomplete stent expansion appeared in 7 (88%) cases. Conclusion:Our study demonstrated that full expansion of the DES and complete lesion coverage must be accomplished, with high pressure inflation or use of cutting balloon preferably under IVUS guidance, for the prevention of ST. Those patients with acute coronary syndrome might warrant intensive antiplatelet therapy, including GPIIbIIIa inhibitors. (Korean Circulation J 2005;35:163-171)

Intracoronary ultrasound

IVUS imaging provides a 2-dimensional, cross-sectional view into the lumen and vessel wall structure of coronary arteries; it is superior to angiography with regard to visualization about several aspects of coronary artery disease. IVUS has given important information on the development and progression of coronary atherosclerosis. Moreover, IVUS has improved our understanding of the mechanisms of percutaneous interventions and restenosis. IVUS-guided balloon sizing during PTCA may increase acute lumen gain as compared to conventional angiographic guidance. Optimization of stent implantation by IVUS guidance also results in larger initial lumen gain than with angiographic control; this approach, however, does not reduce restenosis rates. In summary, IVUS is an optional imaging modality that provides clinically useful information in selected patients.