Lesion morphology and coronary angioplasty: current experience and analysis

Sirolimus-Versus Zotarolimus-Eluting Stents in Acute Coronary Syndromes With C Type Left Anterior Descending Artery Lesions: A Three-Year Clinical Follow-Up

Background

Drug-eluting stents have improved the efficacy of percutaneous coronary intervention and made it the preferred therapy in the treatment of ischemic heart diseases including acute coronary syndromes. The objective of the study was to compare the clinical efficacy and safety of sirolimus-eluting stent with that of zotarolimus-eluting stent following percutaneous coronary intervention for acute coronary syndrome patients with C-type left anterior descending stenosis.

Methods

A total of 154 acute coronary syndrome patients with C-type lesions in the left anterior descending artery, requiring a stent > 28 mm in length, were randomized into two groups to receive either sirolimus- (n = 74) or zotarolimus-eluting stent (n = 80). The follow-up period after stent implantation was approximately 36 months. The primary endpoint was a major cardiac event (a composite of cardiac death, myocardial infarction, or ischemia-related target vessel revascularization), and the secondary endpoint included these individual end points plus stent thrombosis.

Results

After 3 years follow-up, the rate of the primary end point (major cardiac event: cardiac death, myocardial infarction, ischemia-related target vessel revascularization) was 16% in the sirolimus group (n = 12) versus 11.2% in the zotarolimus group (n = 9) (P = 0.2). Although there were four cases of stent thrombosis with sirolimus-eluting stent and one with zotarolimus-eluting stent (4.0% sirolimus vs. 1.25% zotarolimus; P = 0.2), neither non-Q myocardial infarction (4.0%sirolimus vs. 1.25% zotarolimus; P = 0.2) nor stent thrombosis, differed significantly.

Conclusions

Although zotarolimus-eluting stent implantation showed more favorable results with respect to stent thrombosis and major adverse cardiac event rates compared to sirolimus-eluting stent implantation, statistically, both stent groups have nearly similar clinical safety and efficacy in the treatment of acute coronary syndromes with C-type lesions in the left anterior descending artery disease.

Dedicated bifurcation stents

Bifurcation percutaneous coronary intervention (PCI) is still a difficult call for the interventionist despite advancements in the instrumentation, technical skill and the imaging modalities. With major cardiac events relate to the side-branch (SB) compromise, the concept and practice of dedicated bifurcation stents seems exciting. Several designs of such dedicated stents are currently undergoing trials. This novel concept and pristine technology offers new hope notwithstanding the fact that we need to go a long way in widespread acceptance and practice of these gadgets. Some of these designs even though looks enterprising, the mere complex delivering technique and the demanding knowledge of the exact coronary anatomy makes their routine use challenging.

Long-term outcomes with use of intravascular ultrasound for the treatment of coronary bifurcation lesions

Percutaneous coronary intervention (PCI) of bifurcation lesions remains challenging with a higher risk of adverse outcomes. Whether adjunctive intravascular ultrasound (IVUS) imaging improves outcomes of PCI of bifurcation lesions remains unclear. This study sought to determine the long-term clinical outcomes associated with using IVUS for percutaneous treatment of coronary bifurcation lesions. From April 2003 through August 2010, 449 patients with 471 bifurcation lesions underwent PCI with (n = 247) and without (n = 202) the use of IVUS. Clinical outcomes (death, myocardial infarction [MI], periprocedural MI, stent thrombosis, target vessel revascularization [TVR], and target lesion revascularization [TLR]) were compared between patients undergoing PCI with and without IVUS using univariate and propensity score-adjusted analyses. Most patients (61%) presented with acute coronary syndrome and 89% of bifurcations lesions were Medina class 1,1,1. After propensity score adjustment, use of IVUS was associated with significantly lower rates of death or MI (odds ratio 0.38, 95% confidence interval 0.20 to 0.74, p = 0.005), death (odds ratio 0.40, 95% confidence interval 0.18 to 0.88, p = 0.02), MI (odds ratio 0.37, 95% confidence interval 0.14 to 0.98, p = 0.04), periprocedural MI (odds ratio 0.45, 95% confidence interval 0.20 to 0.97, p = 0.04), TVR (odds ratio 0.28, 95% confidence interval 0.14 to 0.53, p <0.0001), and TLR (odds ratio 0.27, 95% confidence interval 0.14 to 0.53, p = 0.0003) compared to no IVUS. In conclusion, IVUS-guided treatment of complex bifurcation lesions was associated with significantly lower rates of adverse cardiac events at late follow-up. Further study is warranted to evaluate the role of IVUS guidance in improving long-term outcomes after PCI of bifurcation lesions.

A modified provisional stenting approach to coronary bifurcation lesions: clinical application of the "jailed-balloon technique"

OBJECTIVES

To demonstrate the application of a novel provisional side branch (SB) stenting strategy for coronary bifurcation lesions using a "jailed-balloon" technique (JBT).

BACKGROUND

Adverse cardiac events are higher for percutaneous coronary intervention (PCI) of bifurcation lesions. Recent studies support the use of provisional SB stenting, but a risk of SB closure and a higher rate of target lesion revascularization (TLR) remain important limitations.

METHODS

From December 2007 to August 2010, 100 patients with 102 bifurcation lesions underwent PCI using the JBT. Baseline and postprocedural quantitative coronary angiography (QCA) analysis were performed. Procedural and immediate clinical outcomes were reviewed.

RESULTS

The majority of patients presented with acute coronary syndrome (68%) and had Medina class 1,1,1 bifurcation lesions (91%). TIMI 3 flow was established in 100% of main branch and 99% of SB lesions. QCA revealed preservation of the bifurcation angle after PCI (pre-PCI: 59.6 ± 30.0; post-PCI: 63.3 ± 26.8, P = 0.41). Nine patients (9%) had lesions that required rewiring and two patients (2%) required provisional stenting of the SB. SB loss occurred in one patient (1%). The jailed-balloon or wire was not entrapped during any PCI. One patient (1%) suffered a periprocedural myocardial infarction (MI).

CONCLUSIONS

Provisional stenting of complex coronary bifurcation lesions using a JBT is associated with a high procedural success rate, improved SB patency, and a low rate of immediate cardiac events. Further study is warranted to evaluate the role of JBT in improving long-term clinical outcomes in PCI of complex bifurcation lesions.

Coronary left main and non-left main bifurcation angles: how are the angles modified by different bifurcation stenting techniques?

BACKGROUND

Investigation of the correlation between bifurcation angles and outcomes is limited with discordant results. The aim of this study is to investigate left main (LM) and non-left main (N-LM) bifurcation angles and their modification after percutaneous coronary intervention (PCI). Measurement of all three angles adds to our understanding of bifurcation anatomy and the resultant effect of different stenting techniques.

METHODS AND RESULTS

All three bifurcation angles were described according to the European Bifurcation Club definition: the A (proximal bifurcation angle), the B (distal bifurcation angle) and the C (main branch angle). Measurements were performed in 75 LM and 140 N-LM bifurcations. In LM bifurcations baseline mean values of C, A, and B were 151 degrees +/- 28 degrees, 131 degrees +/- 32 degrees, and 78 +/- 28 degrees, respectively. In bifurcations with 2 stents the B significantly decreased by a mean of 10 degrees (P = 0.003) and A increased by 10 degrees (P = 0.006). Crush stenting significantly decreased B (A - 14 degrees ; P = 0.020) and increased A (A + 21 degrees; P = 0.005), particularly non-true bifurcations. In N-LM bifurcations mean values for C, A, and B were 156 degrees +/- 19 degrees , 144 degrees +/- 22 degrees, and 60 degrees +/- 20 degrees, respectively. Similar to LM bifurcations, the B became narrower mainly at the expense of the A, which became wider. In both types of bifurcations the greatest variation in A and B was found following 2-stent techniques performed in T-shaped (> or =70 degrees) bifurcations.

CONCLUSIONS

In both LM and N-LM bifurcations we found a significant difference in A and B pre- and post-PCI. This difference was driven by the 2-stent technique and was most evident with a baseline bifurcation angle > or =70 degrees. The Crush technique caused the largest angle variation post-procedure, particularly in non-true LM bifurcations.

On the nature of biomaterials

The situations in which biomaterials are currently used are vastly different to those of just a decade ago. Although implantable medical devices are still immensely important, medical technologies now encompass a range of drug and gene delivery systems, tissue engineering and cell therapies, organ printing and cell patterning, nanotechnology based imaging and diagnostic systems and microelectronic devices. These technologies still encompass metals, ceramics and synthetic polymers, but also biopolymers, self assembled systems, nanoparticles, carbon nanotubes and quantum dots. These changes imply that our original concepts of biomaterials and our expectations of their performance also have to change. This Leading Opinion Paper addresses these issues. It concludes that many substances which hitherto we may not have thought of as biomaterials should now be considered as such so that, alongside the traditional structural biomaterials, we have substances that have been engineered to perform functions within health care where their performance is directly controlled by interactions with tissues and tissue components. These include engineered tissues, cells, organs and even viruses. This essay develops the arguments for a radically different definition of a biomaterial.

Bifurcation disease: what do we know, what should we do?

The percutaneous treatment of coronary bifurcations has moved past an important milestone in that the 1- versus 2-stent debate appears to have been resolved. The provisional approach of implanting one stent on the main branch should be the default approach in most bifurcations lesions. Selection of the most appropriate strategy for an individual bifurcation is important. Some bifurcations require 1 stent, whereas others require the stenting of both branches. Irrespective of whether a 1- or 2-stent strategy is chosen, the results after bifurcation percutaneous coronary intervention (PCI) have dramatically improved. Dedicated bifurcation stents are an exciting new technology that may further simplify the management of bifurcation PCI and change some of these concepts.

Drug-eluting stents in bifurcation lesions: to stent one branch or both?

OBJECTIVES

The objective of this study was to compare two techniques to treat bifurcation lesions: a single drug-eluting stent (DES) implanted in the main branch combined with balloon dilatation for the side branch vs. stenting of both branches (double stent).

BACKGROUND

Percutaneous coronary intervention in coronary bifurcation lesions remains challenging. Although DES reduce restenosis in lesions, the double stent procedure has not shown clear advantages over a single stent with balloon dilation.

METHODS

Fifty-three symptomatic patients with true bifurcation lesions were treated using either the double stent technique (n = 25) or one stent in the parent vessel plus balloon angioplasty of the side branch (n = 28). Procedural results and major adverse cardiac event rates (MACE: cardiac death, myocardial infarction, target vessel revascularization (TVR)) were compared.

RESULTS

Angiographic procedural success (residual stenosis <30% in both branches) was 75% in the single stent group and 100% in the double stent group (P = 0.01). All differences were due to residual stenosis of the side branch. Clinical follow-up (6-18 months) was available for all patients; 90.5% of patients had a coronary angiography or nuclear stress test. Three patients (11%) in the single stent group and two (8%) in the double stent group had ischemia-driven TVR (P = NS). Asymptomatic angiographic restenosis (>50% diameter stenosis) in the ostium of the side branch was seen in two patients in the double-stent group. At 6 months, MACE-free was comparable between groups (89.3% vs. 88%, P = 0.7).

CONCLUSIONS

When treating bifurcation lesions with sirolimus-eluting stents, restenosis following a single stent procedure is comparable to stenting both parent and side branch vessels. Thus, stenting the main-branch lesion, coupled with balloon angioplasty in the side branch, produces a high success rate and good clinical outcomes at 6 months.

Guidewire navigation in coronary artery stenoses using a novel magnetic navigation system: first clinical experience

The objective of this study was to investigate the efficacy of guidewire navigation across coronary artery stenoses using magnetic navigation system (MNS) versus conventional navigation. The MNS is a novel option to facilitate access to target lesions, particularly in tortuous vessels. In an experimental study using a challenging vessel phantom, magnetic-navigated guidewire passage has been reported to reduce fluoroscopy and procedure time significantly. Both magnetic and manual guidewire navigation were attempted in 21 consecutive diseased coronary arteries. The study endpoint was defined as an intraluminal wire position distal to the stenosis. Procedural success was defined as successful guidewire passage without procedural events. Procedure time, amount of contrast, fluoroscopy time, and radiation dose/area product (DAP) were evaluated. There were no procedural events related to either guidewire. Although the lesions attempted had relatively simple and straightforward characteristics, significantly shorter procedure and fluoroscopy time were observed for manual guidewire navigation compared to MNS (median, 40 vs. 120 sec, P=0.001; 38 vs. 105 sec, P=0.001, respectively). Contrast amount and DAP were higher in MNS than in conventional method (median, 13 vs. 9 ml, P=0.018; 215 vs. 73 Gym2, P=0.002, respectively). The magnetic wire did not cross in two vessels. Guidewire navigation using MNS presented a novel, safe, and feasible approach to address coronary artery lesions. Clinical studies are needed to evaluate the potential benefit of the MNS in more complex coronary lesions and tortuous anatomy.

Mechanical thrombectomy options in complex percutaneous coronary interventions

Percutaneous coronary interventions (PCI) of thrombus-containing lesions are associated with an increased risk of acute complications and poorer long term vessel patency. Dealing with these vessels provides many technical challenges, especially with the significant risk of coronary no reflow and distal embolization. Pharmacological strategies, including intravenous and intracoronary glycoprotein IIbIIIa inhibitors reduce intracoronary thrombus propagation, improve TIMI flow and are associated with a reduction in adverse event rates. Mechanical strategies (particularly embolic protection and thrombectomy catheters) help to improve coronary blood flow and myocardial perfusion. However, their impact on clinical outcomes is less clear. The use of embolic protection devices is associated with better perfusion, blood flow, and clinical outcomes among patients undergoing saphenous vein graft (SVG) PCI. However, the role for these devices in primary PCI and native coronary artery interventions is uncertain. This study examines the current approaches to manage thrombotic lesions during PCI and reviews the evidence in support of the different mechanical thrombectomy options that are available to the interventional cardiologist.

Cutting balloons versus conventional long balloons for PCI of long coronary lesions

BACKGROUND

PCI for long coronary lesions remains a challenge because of high incidence of early complications and late restenosis. Cutting balloon angioplasty may result in reduced procedural complications and late restenosis than angioplasty with conventional long balloons (LBA) due to minimized injury to the culprit arteries.

OBJECTIVE

To compare the immediate and one-year outcomes of CBA and LBA for long coronary lesions.

METHODS

169 consecutive patients were retrospectively identified who underwent CBA or LBA for de novo lesions 20 mm in length and 2.5 mm in diameter. The primary endpoint was immediate procedural outcomes and angiographic restenosis at one year.

RESULTS

CBA was performed in 54 patients (56 lesions) and LBA in 115 patients (151 lesions). Baseline characteristics were similar in both groups with a mean lesion length of 34.89+/-11.19 mm, and vessel diameter of 3.03+/-0.54 mm. CBA resulted in reduced incidence of side branch loss (23.2% versus 41.7%, P=0.022) which was associated with less peri-procedural infarction (OR: 11.39 (95% CI: 1.34-96.53), P=0.026). It also caused less dissection (23.2% versus 38.4%, P=0.048) leading to a trend of less provisional focal stenting (32.1% versus 41.1%, P=0.264). The rate of angiographic restenosis and clinically driven target lesion revascularization at one year (follow-up 91.1%) was similar (25% versus 21.2%, and 20.4% versus 20%, for CBA versus LBA, both P=NS). The mean event-free survival was also similar (10.15+/-0.45 months for CBA versus 9.50+/-0.39 months for LBA, P=NS).

CONCLUSION

CBA demonstrated better immediate results and equivalent late results than LBA, and therefore, it may be considered a reasonable firstline approach for PCI of long coronary lesions.

New approaches to long lesions

Long coronary lesions, comprising up to 20% of the interventional practice, pose a significant challenge to the interventionalist. Several approaches have been described to treat long coronary lesions with long-term suboptimal outcomes. Atherectomy and laser treatments with or without adjunctive balloon angioplasty have not been shown to be superior to conventional balloon angioplasty alone. Preliminary data with the use of drug-eluting stents in the treatment of long coronary lesions appears to be promising even in small vessels and may eventually become the mainstay treatment of long lesions.

Antithrombotic therapy during percutaneous coronary intervention: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This chapter about antithrombotic therapy during percutaneous coronary intervention (PCI) is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading, see Guyatt et al, CHEST 2004;126:179S-187S). Among the key recommendations in this chapter are the following: For patients undergoing PCI, we recommend pretreatment with aspirin, 75 to 325 mg (Grade 1A). For long-term treatment after PCI, we recommend aspirin, 75 to 162 mg/d (Grade 1A). For long-term treatment after PCI in patients who receive antithrombotic agents such as clopidogrel or warfarin, we recommend lower-dose aspirin, 75 to 100 mg/d (Grade 1C+). For patients who undergo stent placement, we recommend the combination of aspirin and a thienopyridine derivative (ticlopidine or clopidogrel) over systemic anticoagulation therapy (Grade 1A). We recommend clopidogrel over ticlopidine (Grade 1A). For all patients undergoing PCI, particularly those undergoing primary PCI, or those with refractory unstable angina or other high-risk features, we recommend use of a glycoprotein (GP) IIb-IIIa antagonist (abciximab or eptifibatide) [Grade 1A]. In patients undergoing PCI for ST-segment elevation MI, we recommend abciximab over eptifibatide (Grade 1B). In patients undergoing PCI, we recommend against the use of tirofiban as an alternative to abciximab (Grade 1A). In patients after uncomplicated PCI, we recommend against routine postprocedural infusion of heparin (Grade 1A). For patients undergoing PCI who are not treated with a GP IIb-IIIa antagonist, we recommend bivalirudin over heparin during PCI (Grade 1A). In PCI patients who are at low risk for complications, we recommend bivalirudin as an alternative to heparin as an adjunct to GP IIb-IIIa antagonists (Grade 1B). In PCI patients who are at high risk for bleeding, we recommend that bivalirudin over heparin as an adjunct to GP IIb-IIIa antagonists (Grade 1B). In patients who undergo PCI with no other indication for systemic anticoagulation therapy, we recommend against routine use of vitamin K antagonists after PCI (Grade 1A).

Association of lesion complexity following fibrinolytic administration with mortality in ST-elevation myocardial infarction

Greater lesion complexity, according to the American College of Cardiology and American Heart Association, has been associated with decreased success rates of percutaneous coronary intervention. We hypothesized that greater lesion complexity after fibrinolytic administration for ST-segment elevation myocardial infarction would similarly be associated with increased mortality and other adverse events at 30 days. We studies 2,605 patients from the Thrombolysis In Myocardial Infarction 10B and 14, Integrilin and Tenecteplase in Acute Myocardial Infarction, ENTIRE, and FASTER studies. For all studies, angiographic outcomes were assessed immediately after fibrinolytic administration and clinical outcomes were assessed at 30 days. Greater lesion complexity was associated with poorer epicardial flow and decreased myocardial perfusion at 60 minutes and after percutaneous coronary intervention and with a higher risk of shock and mortality within 30 days. In a multivariate model, type C lesion complexity remained associated with an increased 30-day mortality rate.

Angiographic variables predict increased riskfor adverse ischemic events after coronarystenting with glycoprotein IIb/IIIa inhibition

OBJECTIVES

We sought to assess whether pre-procedural angiographic characteristics are associated with adverse clinical outcomes after coronary stenting with glycoprotein IIb/IIIa inhibition.

BACKGROUND

Ischemic complications after balloon angioplasty are associated with pre- and post-procedural angiographic variables. However, in the current era of stenting with IIb/IIIa inhibition, it is unknown whether angiographic features assessed before intervention confer an increased risk of adverse procedural and subsequent clinical outcomes.

METHODS

In the Do Tirofiban and ReoPro Give Similar Efficacy Outcomes? Trial (TARGET), 4,809 patients undergoing planned stenting were randomized to tirofiban or abciximab. Baseline demographic, clinical, and angiographic variables were obtained. Clinical end points were recorded at 30 days and six months. The relationship between angiographic variables and adverse clinical outcomes was assessed.

RESULTS

Patients with the combination of thrombus, lesion eccentricity, and lesion length >20 mm had a 21.4% composite incidence of death, myocardial infarction, or urgent target vessel revascularization (TVR) at 30 days, compared with 4.2% in those patients without these high-risk features (hazard ratio [HR] 3.24, p < 0.001). After adjustment, the risk was independently associated with thrombus (HR 1.40, p = 0.034), eccentricity (HR 1.67, p < 0.001), and lesion length >20 mm (HR 1.89, p < 0.001). The risk of six-month TVR was independently associated with left anterior descending coronary artery lesions (HR 1.46, p < 0.001), restenotic lesions at baseline (HR 1.58, p = 0.006), and lesion length (HR 1.19, p = 0.03).

CONCLUSIONS

Patients with thrombus, eccentric lesions, or lesion length >20 mm are at high risk for ischemic outcomes after coronary stenting, despite IIb/IIIa inhibition. Further research into novel anti-thrombotic therapies or procedural strategies is necessary for these patients.

Acute and Long-Term Outcomes of Rotational Atherectomy in Small (<3.0 mm) Coronary Arteries

Conventional balloon angioplasty (BA) of small coronary arteries (SCA) is followed by a high rate of restenosis. Rotational atherectomy may be effective as an alternate treatment of stenoses unsuitable for other devices. The purpose of this study was to assess the efficacy of RA in the treatment of SCA. A retrospective analysis was performed of 226 lesions in 159 consecutive patients who underwent RA of SCA (mean diameter = 2.36 +/- 0.49 mm). One hundred forty-eight lesions (65.5%) were type B2 or C of AHA/ACC criteria. Follow-up angiography was performed at 3 and 6 months after the procedure. Procedural success was achieved in 96.9% of patients. The mean burr-to-artery ratio was 0.74 +/- 0.17. Adjunctive BA and stent implantation were needed in 94.2% and 22.6% of lesions, respectively. Minimal lumen diameter (MLD) increased from 0.66 +/- 0.35 mm to 1.97 +/- 0.58 mm (P < 0.01). Angiographic complications consisted of acute reclosure (3.5%), no reflow/slow flow (12.4%), and coronary artery perforation (1.8%). No death, Q-wave myocardial infarction (MI), or coronary artery bypass graft (CABG) occurred during the initial hospitalization. Restenosis rates at 3 and 6 months were 40.6% and 44.2%, respectively, and target lesion revascularization (TLR) rates were 28.5% and 33.0%, respectively. Restenosis and TLR rates during follow-up were comparable among patients who underwent RA + adjunctive BA versus patients who underwent RA + stenting. Long-term clinical follow-up was complete in 143 patients over a mean period of 348 +/- 166 days. The survival free from cardiac death, MI, CABG or repeated BA was 59.6% at 1 year. In conclusion, RA of SCA has relatively high restenosis rates, but may be appropriate for more complex, calcified lesions unsuitable for other devices.

Long balloon angioplasty with focal stenting for the treatment of diffuse coronary artery disease

The objective of this study was to evaluate the efficacy of treating long coronary lesions (> 30 mm) with either a 40 or a 60 mm long Scimed Cobra balloon followed by focal (contingency) stenting of areas with suboptimal results. Diffuse lesion length is a morphological characteristic associated with a poorer clinical outcome after balloon angioplasty with or without stenting. Patients were enrolled in a prospective randomized fashion to have initial PTCA with either a 40 or a 60 mm long balloon followed by focal stenting in areas with suboptimal results. The MACE rate at 6-month follow-up was collected from all patients and was the primary endpoint of the study. A total of 41 patients were enrolled into the study. The acute procedural success rate was 97.5% with a 6-month MACE rate of 9.8%. The use of long balloons with contingency stenting is a highly effective strategy for the treatment of diffuse coronary lesions.

Stenting of bifurcation lesions using the Bestent: a prospective dual-center study

Treatment of bifurcation lesions remains a technical challenge. Among 13 stents previously tested in a bench study, the Bestent seemed of particular interest in this indication as it provided good access to the side branch after stent implantation in the main branch associated with a satisfactory coverage of the lesion after kissing balloon inflation. The use of Bestent implanted in the main branch or both branches for treatment of bifurcation lesions involving a side branch > or = 2.2 mm in diameter was prospectively evaluated in a dual-center prospective study with a prospective 6-month clinical follow-up. All angiographic documents were analyzed by an independent corelab (CORISIS). Between 11 September 1997 and 21 February 1998, 96 patients were consecutively included (mean age, 63.7 +/- 11.4 years; 81.3% male; 58.3% with unstable angina and 6.3% acute myocardial infarction). The lesion involved the left anterior descending-diagonal coronary bifurcation in 55% of cases, left circumflex-marginal 23%, posterior descending-postero-lateral 12%, distal left main 6%, and others 4%. The main branch (proximal reference diameter: 3.43 +/- 0.45 mm) was stented in 98% of cases and the side branch (2.72 +/- 0.38 mm) in 38% (both branches in 34% of cases). T-stenting or provisional T-stenting was used in 88% of cases and final kissing balloon inflation was performed in 78% of cases. Procedural success was obtained in 100% of cases in the main branch and 98% in both branches. Major cardiac and cerebral events (MACCE) during hospitalization occurred in 4.2% of cases, non-Q-wave myocardial infarction (MI) in 3.1%, Q-wave MI in 1.0%, repeat PTCA in 2.1%; there were no major access site complication, no emergency coronary artery bypass grafting operation, no death. At 6-month follow-up, total MACCE rate was 14.6% (Q-wave MI, 3.1%; non-Q-wave MI, 3.1%; target vessel revascularization, 9.4%; death, 2.1%). Patients with target vessel revascularization (TVR) had restenosis of both branches in 22.2% of cases, main branch in 22.2%, and side branch in 55.6%. This study shows that using a simple strategy of provisional T-stenting of the side branch in the majority of cases, the Bestent can be used for treating bifurcation lesions with a high rate of success and an acceptable rate of TVR at 6-month follow-up.

Evaluation of the Society for Coronary Angiography and Interventions' lesion classification system in 14,133 patients with percutaneous coronary interventions in the current stent era

We recently showed that the ACC/AHA coronary lesion classification could be simplified with no loss of predictive value (SCAI I = patent/non-C; SCAI II = patent/C; SCAI III = occluded/non-C; SCAI IV = occluded/C). We now test this system in a database reflecting current stent usage. Data from 14,133 patients with single-native-vessel interventions recorded in the Society for Coronary Angiography and Interventions (SCAI) Registry from July 1996 to July 1999 were analyzed. Stents were used in 60.2% of procedures. Logistic models predicting angiographic success suggested a slight, clinically insignificant preference for the SCAI classification (c-statistic = 0.692 vs. 0.670). Models using clinical variables to predict major complications were superior to models using only lesion classification. Lesion characteristics were related to outcomes primarily in elective (not acute myocardial infarction) patients. In the current PCI device era, the simpler SCAI classification using 7 variables predicted interventional success and complications as well as or better than the ACC/AHA system requiring 26.

Application of excimer laser angioplasty in acute myocardial infarction

BACKGROUND AND OBJECTIVE

Patients presenting with acute myocardial infarction who fail to respond to standard therapy with thrombolytics or have contraindications for their use oftentimes need revascularization with a mechanical device for removal of an occlusive coronary thrombus and its underlying atherosclerotic plaque. As both thrombi and plaques absorb laser energy in the ultraviolet wavelength (308 nm), we studied the feasibility and safety of excimer laser angioplasty in selective patients with complicated acute myocardial infarction.

STUDY DESIGN/MATERIALS AND METHODS

Fifty patients with acute myocardial infarction complicated by continuous chest pain and/or ischemia who had a total of 54 obstructive lesions were treated with percutaneous excimer coronary laser angioplasty (ELCA). A Q-wave myocardial infarction was documented in 56% and a non-Q-wave myocardial infarction in 44%. The baseline left ventricular ejection fraction was reduced at 43 +/- 13% and six patients (12%) presented to the cardiac catheterization laboratory in cardiogenic shock. Twenty-nine patients failed to respond to thrombolytic therapy and 16 had contraindications for thrombolytics and IIb/IIIa receptor antagonists. Following laser debulking, all patients received adjunct balloon dilation and then stents were deployed in 83% of the target lesions. Quantitative coronary arteriography (QCA) was performed at an independent core laboratory.

RESULTS

Ninety-eight percent laser success and 100% procedural success were achieved. By QCA the minimal luminal diameter increased from baseline of 0.7 +/- 0.5 to 1.3 +/- 0.5 mm post-lasing and then to 2.0 +/- 0.6 with balloon dilation to a final of 3.0 +/- 0.5 mm. Pre-laser percent stenosis diameter of 77 +/- 17% was reduced to 51 +/- 22% post-laser to 3.0 +/- 17% post-balloon and to a final of 15 +/- 25%. An 83% laser-induced reduction of thrombus burden area was achieved as well as an increase in TIMI flow from baseline of 1.7 +/- 1.1 to 2.8 +/- 0.4 by laser to a 2.9 +/- 0.4 final. There were no deaths, emergency bypass surgery, cerebral vascular accident, neurologic injury, or major perforation. In one case, a laser-induced major dissection was successfully treated by stenting. All 50 patients survived the procedure, improved clinically, and were discharged.

CONCLUSION

Application of excimer laser coronary angioplasty is feasible and safe in selected patients with acute myocardial infarction who either fail to respond to thrombolytics or have contraindications to these agents. Intracoronary thrombus at the target lesion can be successfully dissolved with this wavelength laser energy without adverse effect on the procedure results.

Intravascular ultrasound-guided stenting in long lesions: an insight into possible mechanisms of restenosis and comparison of angiographic and intravascular ultrasound data from the MUSIC and RENEWAL trials

The high restenosis rates in long stents may be related to suboptimal stent deployment. In an attempt to understand the potential components associated with restenosis in long stents, this study compares angiographic and intravascular ultrasound (IVUS) data from the MUSIC and RENEWAL studies where IVUS was used to optimize stent deployment in short (< 15 mm) and long (> 20 mm) coronary lesions, respectively. The RENEWAL study, a randomized trial, compared the NIR stent and Wallstent in long (> 20 mm) coronary lesions and used on-line visual IVUS criteria to optimize stent expansion. Detailed analysis of IVUS data was performed off line. Angiographic and IVUS data from this study was compared to that from the MUSIC study. Initial stent deployment was deemed optimal by the operator after visual angiographic and IVUS assessment in 50 of 70 lesions. In the remaining 20 lesions further balloon inflations were required to optimize stent apposition that led to an average gain in minimal in-stent luminal area (MISA) of 15.9% (P < 0.01). Off-line IVUS data analysis showed that the number reaching "MUSIC criteria" for optimal stent deployment preredilatation was 8 (11.4%) of 70 and 14 (20%) of 70 postredilatation. The ratio of MISA/MRAprox (mean proximal reference area) was 0.69 in RENEWAL. At 6-month follow-up, the angiographic restenosis rate in RENEWAL was 36% and target lesion revascularization (TLR) rate was 7.8%, compared with MUSIC's 9.7% and 4.5%, respectively. In conclusion, angiographic assessment of stent deployment in long lesions is limited. On-line visual IVUS with further balloon inflations to improve stent apposition led to a significant gain in MISA, but the MISA/MRAprox ratio remained suboptimal. Therefore, suboptimal stent deployment due to constraint by lesion resistance may be an important mechanism underlying the high restenosis rates in long stents.

Provisional bifurcation stenting

Obstructive coronary lesions involving a branch origin or extending into the branch itself, remain one of the main challenges in the rapidly developing world of interventional cardiology. Acutely, these lesions are prone to the complications resulting in significant residual stenosis or loss of one of the branches. Long-term follow up has also been disappointing with a high incidence of restenosis. Numerous techniques have been developed, aimed at optimizing the acute and long-term results by adapting standard angioplasty hardware, with limited success, particularly in the long term. This article describes a fully dedicated system for bifurcation lesions with stenting of the main vessel to the main branch, yet ensuring side branch patency, with limited risk of branch origin stenosis or stent jailing, allowing for provisional stenting of the branch as dictated by the angiographic outcome.

Late (> 48 hr) myocardial infarction after PTCA: clinical and angiographic characteristics of infarction related or not to the angioplasty site

Since late myocardial infarctions after percutaneous coronary interventions have not been well characterized, we intended to evaluate the characteristics of myocardial infarctions occurring > 48 hr after balloon angioplasty of native coronary arteries or saphenous vein grafts. The Montreal Heart Institute database (1985-1996) was interrogated for all patients readmitted with a diagnosis of MI more than 48 hr after successful percutaneous transluminal coronary angioplasty (PTCA). We compared the clinical, procedural, and angiographic variables between MIs related or not to the index PTCA site. One hundred and ninety-three patients presented with late myocardial infarction (MI) following balloon angioplasty. The median time elapsed between PTCA and MI was 55 days compared to 968 days when MI was unrelated to the PTCA site. MIs related to the PTCA site were more likely non-Q-wave (76% vs. 35%, P = 0.0001) with less marked CK-MB rise. Angiography showed less complex lesions (63% vs. 90%, P = 0.001) and better thrombolysis in myocardial infarction (TIMI) grade flow (TIMI II to III, 66% vs. 56%, P = 0.01) when the culprit lesion was at the PTCA site. Independent predictors of MI at the PTCA site were vein graft dilation, female sex, and residual stenosis post-PTCA. Myocardial infarctions occurring late after PTCA have a distinct time course and present specific characteristics according to their relationship or not to the previously dilated site.

ABC stenosis morphology classification and outcome of coronary angioplasty: reassessment with computing techniques

BACKGROUND

The American College of Cardiology/American Heart Association (ACC/AHA) stenosis morphology classification (MC) stratifies coronary lesions for probability of success and complications after coronary angioplasty (PTCA). Modern computing techniques were used to evaluate the individual predictive value of MC in random PTCA cases.

METHODS AND RESULTS

MC was attributed to the target lesions by consensus of 2 observers. The predictive value regarding procedural success (PS) and major adverse cardiac events (MACE) of MC was analyzed by conventional logistic regression analyses and by inductive machine learning models. The study was adequately powered for the methods applied with 325 target lesions of 250 cases. Overall, PS decreased and MACE increased from type A to type C lesions. Regression analysis identified no single factor as predictive. Logistic regression showed an error rate of 42%. Machine learning techniques achieved an individual predictive error of only 10%, which could be further reduced to 2% by addition of parameters. For PS, MC parameters showed a high ranking for building the model. For MACE, variables of the medical history showed more impact.

CONCLUSIONS

MC per se cannot individually predict PS or MACE. However, when all MC parameters are integrated together with additional lesion-specific and history variables, a high individual predictive value can be achieved. This technique may be clinically helpful for risk stratification in the catheterization laboratory and improvement of classification systems in interventional cardiology.

Clinical and technical determinants of the complexity of percutaneous transluminal coronary angioplasty procedures: analysis in relation to radiation exposure parameters

Few data are available on the quantitative assessment of complexity (C), especially in relation to a patient's exposure to radiation. The relationship between several clinical (CFs), anatomic (AFs), and technical factors (TFs) versus fluoroscopy time (FT) was evaluated in 402 random percutaneous transluminal coronary angioplasty (PTCA) procedures. CFs were age, sex, single or multivessel disease, ejection fraction, and previous coronary artery bypass graft. AFs were assessed based on the American Heart Association / American College of Cardiology classification. TFs were multivessel PTCA, use of the double wire or double balloon technique, stenting, ostial stenting, bifurcation stenting, and intravascular ultrasonography. No CFs significantly influenced FT, whereas all AFs and TFs (except multivessel PTCA) did significantly influence FT. A scoring system was developed, and two complexity indexes (CI) were conceived, based on which the procedures were divided into three groups: simple, medium, and complex. The mean FTs were 471+/-289, 805+/-532, and 1,190+/-641 (P <0.0001), respectively. Total cine frame recordings were 1,119+/-572, 1,265+/-644 (P = 0.0355), and 1,418+/-785 (P<0.0001 vs. simple; P = NS vs. medium). The dose/area product measurement was 65.8+/-41.4, 93 +/-58.5 (P<0.0001), and 116.7+/-72.8 (P<0.0001 vs. simple; P = 0.00159 vs. medium), respectively. In our series, CI was directly related to AF and TF, but not to CF. Comparison of PTCA procedures and definition of appropriate FT should consider CIs.

Recanalization of chronic total coronary occlusions: the impact of a new specific guidewire on primary success rate

BACKGROUND: Although chronic total occlusions are encountered frequently in patients with coronary artery disease, an effective strategy to deal with them has yet to be devised. Various new guidewires have been designed in an attempt to negotiate chronic occlusions successfully. The authors have analysed the impact of the Athlete guidewire on procedural success in this lesion subset. METHODS: Sixty-two consecutive patients undergoing percutaneous intervention for chronic total occlusions over a two-year period were retrospectively studied. For the initial attempt, conventional guidewires were used. In case of failure, further attempts were made using the Athlete guidewire. Procedural success rates with the use of conventional and Athlete guidewires were assessed. RESULTS: Failure of the first attempt with the conventional guidewire occurred in 32 (51.6%) patients and success was achieved in 30 (48.4%) patients. In the former patients, a second attempt was made using the Athlete guidewire to cross the occlusion. The second attempt was successful in 20 patients (60%) in whom the first attempt was unsuccessful, while in the remaining 12 (40%) patients the occlusion could not be crossed even during the second attempt and the procedure was then terminated. Following the use of the Athlete guidewire, the success rate increased to 62% (p < 0.001). No complication occurred during the first attempt, while one patient had a coronary perforation using the Athlete guidewire, which was managed successfully without the need for bypass surgery. CONCLUSION: The use of the Athlete guidewire is feasible and safe, and enhances the chances of successfully treating chronic total occlusions during percutaneous coronary revascularization procedures.

A simplified lesion classification for predicting success and complications of coronary angioplasty. Registry Committee of the Society for Cardiac Angiography and Intervention

In 1988, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures presented a classification of coronary lesions utilizing 26 lesion features to predict the success and complications of balloon angioplasty. Using data from the Registry of the Society for Cardiac Angiography and Interventions (SCAI) we evaluated the ability of this classification to predict success and complications. Lesion success, death in hospital, emergency cardiac bypass surgery, and major adverse events were evaluated in 41,071 patients who underwent single-vessel angioplasty from January 1993 to June 1996. Logistic models using the ACC/AHA lesion classification, vessel patency, or both, were compared. A new classification based on the interaction of the ACC/AHA classification plus lesion patency was compared with the existing ACC/AHA classification. Vessel patency, added to the ACC/AHA classification, improved prediction of lesion success (p </=0.0001). Class A and patent B lesions had similar success and complication rates, so a simplified classification (SCAI) using only 7 lesion characteristics could be created. This system (I: non-C patent, II: C patent, III: non-C occluded, and IV: C occluded) improved prediction of lesion success compared with the ACC/AHA classification (Bayesian Information Criterion statistic: ACC/AHA 16539, SCAI 15956; and area under the receiver- operating characteristics curve 0.659, 0.693, respectively). The SCAI classification was preferred for predicting major complications and in-hospital death and was similar to the ACC/AHA classification for predicting emergency bypass surgery.

Triage of patients for short term observation after elective coronary angioplasty

OBJECTIVE

To evaluate triage of patients for short term observation after elective percutaneous transluminal coronary angioplasty (PTCA), as appropriate selection of patients for short term observation after angioplasty may facilitate early discharge.

METHODS

1015 consecutive patients scheduled for elective PTCA were prospectively included for short term observation. Patients with unstable angina Braunwald class III were excluded. There were no angiographic exclusion criteria. Patients were discharged from the interventional centre when considered stable during 4 hours of observation after PTCA. It was left to the operator's discretion whether to prolong the observation period. Procedural complications were defined as death, coronary bypass surgery, early repeat PTCA, and myocardial infarction.

OUTCOME MEASURES

The need for prolonged observation (> 4 hours) and the occurrence of complications. Predictors for prolonged observation and the occurrence of complications after the 4 hours observation were assessed by univariate and multivariate analysis.

RESULTS

Two patients died, including one of six patients who underwent emergency bypass surgery. In all, 922 patients (90.8%) were triaged to short term observation and had an uncomplicated three day follow up. Observation was prolonged in 87 patients (8.6%), and 40 patients had a complicated course. Independent predictors of procedural complications were acute closure (odds ratio (OR) 9.7; 95% confidence interval 4.4 to 21.4), side branch occlusion (OR 8.9; 3.4 to 23.7), no angiographic success (OR 5.1; 2.4 to 11.0), female sex (OR 3.1, 1.7 to 5.7), any unplanned stent (OR 2.8, 1.4 to 5.9), and ostial lesion (OR 2.2, 1.0 to 4.7).

CONCLUSIONS

A 4 hour observation period is safe after elective coronary angioplasty. As procedural variables are the strongest predictors of postprocedural complications, the immediate procedural results allow effective triage of patients for short term or prolonged observation in order to anticipate complications.