Evaluating new devices. Acute (in-hospital) results from the New Approaches to Coronary Intervention Registry

Excimer Laser Atherectomy in Percutaneous Coronary Intervention: A Contemporary Review

Excimer laser coronary atherectomy (ELCA) during percutaneous coronary intervention (PCI) has been in use for more than twenty years. While early experiences were not favorable over balloon angioplasty alone, with improvement in operator technique, patient selection and technology, ELCA has established its own niche in contemporary PCI as a safe and effective atherectomy strategy. With growing experience in complex coronary interventions worldwide, ELCA has become one of the essential atherectomy tools offering unique advantages over other atherectomy devices. In the modern era, ELCA is commonly used for patients with in-stent restenosis, stent under expansion, balloon uncrossable lesions and chronic total occlusions. Technical success rates are reported to be >80% in most situations while procedural complication rates such as vessel dissection and perforation among others are reported to average 9% over the past 25 years with improvement over time. In this review, we provide a comprehensive systematic review of the ELCA system, its practical use, indications, and procedural techniques in the contemporary PCI era.

Applying drug-eluting stents in clinical practice

The use of percutaneous coronary interventions has resulted in significant improvement in patient care; however, the risk for restenosis remains a major limitation. Drug-eluting stents represent an impressive breakthrough in the evolution of interventional cardiology, but it is important to understand the limits to their added benefit. Safety of the procedure must continue to be the first consideration, and technique must not be compromised to accommodate new technology.

From balloon angioplasty to drug-eluting stents: revolution or evolution?

Drug-eluting stenting is part of the evolution of interventional cardiology that started with Gruentzig's introduction of balloon angioplasty in 1977. Numerous advances in interventional cardiology technique have occurred since that time, and drug-eluting stents hold promise for reducing the restenosis rate but as yet have not been shown to influence survival or freedom from myocardial infarction. The ability of stents to influence these hard end points will be tested against the most difficult patient subset for interventional cardiology: persons with diabetes mellitus and multivessel disease. As more data are accumulated, prudent selective use of drug-eluting stenting seems most appropriate.

Unrestricted availability of intracoronary stents is associated with decreased abrupt vascular closure rates and improved early clinical outcomes

The purpose of this study was to determine whether the unrestricted availability of intracoronary stents is affecting abrupt vascular closure rates and early clinical outcomes. Intracoronary stents have improved procedural outcome despite their application in more complex lesions, but the impact of unrestricted availability of stents on abrupt closure and early clinical outcomes is unknown. Two cohorts were identified retrospectively from a coronary intervention registry: patients treated between 1988 and 1992 (n = 3,617) when stents were not generally available, and patients treated between 1994 and 1997 (n = 4,518) when stents were freely available. The late cohort patients consisted of more females; it also had greater comorbidity and more complex presentation. However, there was a significant reduction in the abrupt closure rates between the two time periods (7% vs. 4%, P < 0.0001). After adjusting for female gender, thrombus, and lesion angulation, the late cohort remained significantly associated with decreased odds of abrupt closure (odds ratio [OR] = 0.62, 95% upper and lower confidence intervals [CI] = 0.52-0.75, P = 0.0001). The late cohort also had decreased in-hospital mortality (OR = 0.91, CI = 0.86-0.95, P = 0.0002) and major adverse clinical event (OR = 0.93, CI = 0.91-0.96, P = 0.0001). Unrestricted availability of intracoronary stents is associated with reduced abrupt closure rates and improved early clinical outcomes among patients undergoing coronary intervention despite treatment of high-risk patients.

Effectiveness of and adverse events after percutaneous coronary intervention in patients with mild versus severe renal failure

Patients with renal failure undergoing percutaneous coronary intervention (PCI) experience reduced procedural success rates and increased in-hospital and long-term follow-up major adverse cardiac events. This study was designed to determine whether the severity of preprocedural renal failure influences the outcomes of patients with renal failure undergoing PCI. We compared the immediate and long-term outcomes of 192 patients with mild renal failure (creatinine 1.6 to 2.0 mg/dl, mean 1.76) with those of 131 patients with severe renal failure (creatinine >2.0 mg/dl, mean 2.90), selected from 3,334 consecutive patients undergoing PCI between 1994 and 1997. Although the overall population with renal failure represents a high-risk group, the severe renal failure cohort had a higher incidence of hypertension, multivessel disease, prior coronary bypass surgery, vascular disease, and congestive heart failure (all p values <0.05), yet had similar angiographic characteristics. Procedural success was higher in the group with severe renal failure (93.7% vs 87.7%, p = 0.04). There were no statistically significant differences in in-hospital mortality (11.5% vs 9.9%, p = 0.7), Q-wave myocardial infarction (0.5% vs 0%, p = 0.4), emergent bypass surgery (0% vs 0%, p = 1.0), and in-hospital major adverse cardiac events (11.5% vs 9.9%, p = 0.7) between the mild and severe renal groups, respectively. Kaplan-Meier analyses showed no statistically significant difference in long-term survival (log rank test, p = 0.1) or event-free survival (log rank test, p = 0.3) between the 2 groups. Finally, creatinine was not identified as an independent predictor of in-hospital or long-term follow-up major adverse cardiac events. In our high-risk population, patients with mild renal insufficiency undergoing PCI experience major adverse outcomes in the hospital and at long-term follow-up similar to those of patients with severe renal failure.

The effects of contemporary use of coronary stents on in-hospital mortality. Registry Committee of the Society for Cardiac Angiography and Interventions

OBJECTIVES

This study was designed to determine the effect of coronary stents on in-hospital mortality.

BACKGROUND

Despite extensive use of stents for percutaneous coronary interventions (PCIs), their effect on serious in-hospital events, especially mortality, is not well defined.

METHODS

A cohort study was performed using 16,811 consecutive native-vessel PCI procedures performed on patients in the Society for Cardiac Angiography & Interventions Registry from July 1, 1996, through December 31, 1998. Patients undergoing balloon-only angioplasty were compared with those receiving a planned or unplanned stent. Procedures with other devices were excluded. Multivariable analyses adjusted for detailed clinical characteristics and for individual laboratory.

RESULTS

Stents were associated with a significant reduction in in-hospital mortality (0.3%) compared with balloon procedures (0.6%; multivariable odds ratio [OR] 0.55; 95% confidence interval [CI] 0.34, 0.89; p = 0.014). The risk of emergency coronary bypass also was reduced by stenting (0.3% vs. 0.7%; multivariable OR 0.47; 95% CI: 0.29, 0.76; p = 0.002). Adjustment for the use of glycoprotein IIb/IIIa inhibitors did not change the results, and the effects of stenting relative to balloon procedures were similar in those procedures with and without glycoprotein IIb/IIIa blockade (p = 0.94).

CONCLUSIONS

This study suggests that coronary stenting, compared with balloon procedures, reduces in-hospital mortality, independent of the clinical setting.

Importance of lesion length on new device angioplasty of native coronary arteries. NACI Investigators. New Approaches to Coronary Interventions

The influence of lesion length on early and late outcomes after new device angioplasty has not been well documented. We reviewed the clinical and angiographic outcomes of 2,980 patients (3,902 lesions) undergoing new device angioplasty of native vessels enrolled in the New Approaches to Coronary Interventions (NACI) Registry. Patients were divided into three groups according to the longest lesion length (< 10, 10-20, and > 20 mm) treated. Patients with the longest lesions had more multivessel disease (56.9% vs. 49.0%, P<0.05), right coronary artery disease (52.7% vs. 32.0%, P<0.001), and total occlusions (19.1% vs. 2.5%, P<0.001) than patients with shorter lesions. Longest lesions had the smallest minimal lumen diameter (P<0.001) at baseline and at the end of the procedure. Although in-hospital events were similar, there were differences in clinical outcomes at 1 year due mainly to more target lesion revascularization in the longest lesion group (P<0.01). Multivariate analysis showed that each 1-mm increase in lesion length was associated with an increase relative risk of 1.014 (95% CI, 1.004-1.025) for target lesion revascularization at 1 year. We conclude that despite similar early clinical events, patients undergoing new device angioplasty of longer lesions have more target lesion revascularization at 1 year.

Relation of coronary artery size to one-year clinical events after new device angioplasty of native coronary arteries (a New Approach to Coronary Intervention [NACI] Registry Report)

The influence of vessel size on clinical and angiographic outcomes after new device angioplasty has not been well documented. We reviewed clinical and angiographic outcomes of 2,044 patients undergoing new device angioplasty of native vessels enrolled in the New Approaches to Coronary Interventions (NACI) Registry. Quantitative angiography was performed using standard methods. Patients were divided into 3 groups according to reference vessel diameter (RVD) (<2.75, 2.75 to 3.25, and >3.25 mm). Patients with the smallest vessels had a higher incidence of diabetes (26% vs. 16%, p<0.01), multivessel disease (50% vs. 45%, p<0.01), left anterior descending coronary artery disease (61% vs. 39% p<0.01), and in general, more severe baseline lesion characteristics than patients with larger (>3.25 mm) vessels. Absolute baseline and final minimal lumen diameter (MLD) was also smaller in patients with RVD <2.75 mm despite similar final percent diameter stenosis. Although in-hospital events were similar, patients who underwent interventions in vessels <2.75 mm had an increased incidence of death (p<0.01), surgical revascularization (p<0.05), and target lesion revascularization (TLR) (p<0.01) at 1 year. Multivariate analysis by vessel size showed a stepwise increase in the risk of TLR by 1 year in patients with the smaller RVD (p = 0.0001) and the combined end point of 1 year death/Q wave-myocardial infarction/TLR (p = 0.02). Thus, despite similar early clinical events among patients undergoing new device angioplasty, patients who underwent treatment of smaller vessels had a significantly increased risk of major adverse clinical events and particularly TLR by 1 year after new device angioplasty of native coronary arteries.

Risk of distal embolization and infarction with transluminal extraction atherectomy in saphenous vein grafts and native coronary arteries. NACI Investigators. New Approaches to Coronary Interventions

Lower success rates have been reported when treating high-risk lesions in saphenous vein grafts (SVGs) and native coronary arteries with balloon angioplasty. The transluminal extraction atherectomy catheter (TEC) has been proposed to reduce the incidence of distal embolization (DE) in subsets of high-risk lesions. To define the utility of TEC in reducing the incidence of DE, all patients who were enrolled in the New Approaches to Coronary Interventions (NACI) Registry and had TEC planned as the sole treatment were studied (329 patients with 381 lesions). Of the lesions treated, 75.9% were in SVGs; 37.5% were thrombotic; and 15% were total occlusions. Adjunctive percutaneous transluminal coronary angioplasty (PTCA) was performed in 87.4% of lesions. Multivariate predictors of DE were: noncardiac disease, stand alone TEC, thrombus, and larger vessel size. DE was associated with an 18.5% in-hospital mortality vs. 3.0% without DE (P < 0.01) and a 25.9% MI rate vs. 5.0% without DE (P < 0.01). In conclusion, in this high-risk subset of patients, TEC is associated with an 8.3% incidence of DE with thrombotic and SVGs lesions. DE associated with TEC appears to carry high morbidity and mortality. Additional techniques to control DE are needed to reduce the frequency of complications in these patients.

Stent thrombosis: incidence and related factors in the R.I.S.E. Registry(Registro Impianto Stent Endocoronarico)

Although stent thrombosis has been greatly reduced by adequate stent expansion with high-pressure balloon inflations and by the use of antiplatelet drugs, this event is still frightening, as it may lead to acute myocardial ischemia resulting in acute myocardial infarction or sudden death. Therefore, the definition of factors associated with stent thrombosis may provide a better understanding of the mechanisms underlying this phenomenon and may permit us to define therapeutic strategies to further reduce its occurrence. The purpose of this study was to assess factors responsible for the occurrence of stent thrombosis after coronary stent implantation in 939 consecutive patients enrolled in the Registro Impianto Stent Endocoronarico (R.I.S.E. Study Group). Consecutive patients undergoing coronary stent implantation at 16 medical centers in Italy were prospectively enrolled in the registry. Clinical data, and qualitative and quantitative angiographic findings were obtained from data collected in case report forms at each investigator site. The study group consisted of 781 men and 158 women with a mean age of 59 yr: 1,392 stents were implanted in 1,006 lesions and expanded at a maximal inflation pressure of 14.7 +/- 3 atm. The great majority of patients (92%) received only antiplatelet drugs after coronary stenting. During hospitalization there were 45 major ischemic complications in 39 patients (4.2%): 13 events were related to acute or subacute thrombosis (1.4%). Another stent thrombotic event occurred in the first month of follow-up. On multivariate logistic regression analysis, stent thrombosis was related to the following factors: unplanned stenting (OR 3.46, 95% CI 1.65-7.23), unstable angina (OR 3.37, 95% CI 1.11-10.14) and maximal inflation pressure (OR 0.83, 95% CI 0.75-0.93). In conclusion, this registry shows that in an unselected population of patients undergoing coronary stenting, stent thrombosis occurs in less than 2% of patients and is significantly related to unplanned stent implantation, unstable angina, and maximal inflation pressure. The incidence of this phenomenon is likely to be further reduced by the use of new potent antiplatelet drugs, such as platelet glycoprotein IIb/IIIa antagonists.

Failed coronary stent deployment

BACKGROUND

Coronary stent deployment failure may be more common in clinical practice than generally appreciated. The incidence of failed deployment in routine clinical practice and the clinical sequelae have not been described. This study sought to determine the incidence and consequences of failed coronary stent deployment and to identify clinical and angiographic characteristics associated with deployment failure.

METHODS AND RESULTS

A series of 1303 consecutive procedures involving attempted coronary stenting were reviewed retrospectively. Failed stent deployment was defined as failure of the stent to be either delivered to or adequately deployed at the target lesion site. Clinical records and angiograms were reviewed and qualitative coronary angiography was performed for all cases of failed deployment. Deployment was unsuccessful in 108 (8.3%) cases involving 134 stents. Stenting was attempted as a primary procedure in 40%, as bailout in 18%, and for suboptimal angioplasty in 43% of cases. In 87% of cases, attempts were made to withdraw the stent from the coronary artery. Stent retrieval was successful in 45%, peripheral embolization occurred in 38% of patients, and in 4% the stent dislodged in the left main artery. In 35% of cases, additional stent(s) were successfully deployed. Deployment failure was associated with an overall in-hospital adverse outcome in 19% of patients, including 16% urgent coronary artery bypass grafting, 5% nonfatal myocardial infarction, and 3 in-hospital deaths. At 6-month follow-up, 39% of patients had had at least 1 adverse clinical outcome of death, myocardial infarction, or repeat target lesion revascularization.

CONCLUSIONS

Failure to deploy stents is a serious and relatively common problem that is associated with significant morbidity and mortality rates. Improved deployment strategies, including new stent designs, are required to improve procedural outcomes.

How to standardize vasomotor tone in serial studies based on quantitation of coronary dimensions?

In patients with coronary artery disease including those after coronary bypass graft operation and heart transplantation intervention studies based on serial quantitative coronary angiography, in part combined with intravascular ultrasound, are of increasing relevance. Since vasomotor tone of epicardial coronary arteries is influenced by a variety of factors, angiographic follow-up studies require standardization of coronary tone by induction of maximal dilation. We reviewed the effects of the most potent coronary vasodilatory drug groups, calcium antagonists and nitrocompounds, on coronary diameters. Intravenous or intracoronary injections of verapamil, diltiazem, nifedipine, nicardipine, and nisoldipine can cause profound coronary dilation which has been shown to be maximal with verapamil and nisoldipine. Shortcomings of calcium antagonists include short or unknown duration of action after bolus administration, severe drop in blood pressure, and lack of commercial availability of solutions for injection of many substances. Isosorbide dinitrate induces profound coronary dilation; however, after sublingual administration marked blood pressure decrease can occur, and the duration of action and ideal dose of intracoronary isosorbide dinitrate has not been investigated yet. Injections of molsidomine and its active metabolite, SIN-1, cause longlasting, reproducible, maximal coronary dilation, although only after a waiting period of at least 10 minutes; unfortunately, SIN-1 is only commercially available in France. Nitroglycerin induces reproducible maximal coronary dilation and is easy to administer sublingually or as intracoronary bolus injection with rapid onset of action and no major side effects. The short duration of action may require repeated administrations. To date, repeated intracoronary bolus injections of 0.1 mg nitroglycerin every 10 minutes seem to be the optimal known regimen for standardization of coronary vasomotor tone in serial angiographic studies. Further investigations in this field with old and new vasodilatory drugs are recommendable.

New devices enhance hospital results of coronary angioplasty

After rigorous screening by means of registries and controlled trials, various atherectomy devices, excimer laser catheters, and endoluminal stents were approved for general clinical use. Few data are available describing their safety and effectiveness after approval. This analysis was undertaken to assess the impact on patient outcomes of the unrestricted clinical application of new transcatheter devices for coronary angioplasty. Thirty-six cardiologists performed 3,113 transcatheter procedures during 1995. Each chose the transcatheter modality best suited to the clinical and angiographic features of the patient. Baseline clinical and angiographic data and initial outcome were recorded by cardiac catheterization laboratory personnel. In-hospital events were obtained by independent chart review. Balloon angioplasty alone was employed in 1,089 (35.0%) patients. A stent was deployed after balloon angioplasty in 1,029 (33.1%) patients. An atherectomy or laser device was used without stent support in 631 (20.3%) patients, and stent support was added in an additional 364 (11.7%) patients. In all three new device categories the angiographic success (final luminal narrowing <50%) rate was better than in balloon angioplasty for type-C lesions and for chronic occlusions. The frequency of adverse events in the aggregate was not increased with device use, but the frequency of coronary artery bypass surgery was reduced with stent use. The frequency of non-Q-wave myocardial infarction was greater with devices than with balloon angioplasty alone. After adjustment for the differences in baseline clinical and angiographic variables by means of multivariate analysis, each of the three new device categories was independently associated with an increased chance of angiographic and procedural success compared to balloon angioplasty. The availability of new transcatheter devices for clinical practice enhances patient outcomes during hospitalization for the procedure.

Focal angioplasty: theory and clinical application

Percutaneous transluminal coronary angioplasty (PTCA) has been performed with 20 mm long uni-diameter balloons for over 17 years with excellent results. It has now become possible to combine both compliant and non-compliant balloon material on a single device, allowing the interventionalist to direct the force of dilation to the lesion focally. This concept has been termed "focal angioplasty." This article reviews the concept of focal angioplasty, including the physics of balloon dilation, and describes current clinical applications for focal angioplasty. We discuss use of the focal angioplasty technique for PTCA and stenting and review the results of several ongoing clinical trials. While the acute results using focal angioplasty have been promising, long-term benefits have not been fully studied and will require completion of ongoing trials.

Treatment of in-stent coronary restenosis by excimer laser angioplasty

We evaluated the efficacy and safety of excimer laser angioplasty (ELCA) with adjunctive balloon angioplasty in patients with restenotic or occluded coronary stents. ELCA was performed in 70 patients (60 +/- 9 years), who had previously been treated with Micro Stents (n = 65), Palmaz-Schatz (n = 38), Wiktor, NIR, Freedom, and Multi-Link stents (n = 1 each). Restenosis (> or =50% diameter stenosis) was documented in 90 stents, another 17 stents were occluded. Laser energy was delivered to the lesions with catheters 1.4, 1.7 (eccentric), and 2.0 mm in diameter. Procedural success was controlled by intravascular ultrasound in a subgroup. Laser catheters crossed all restenotic or occluded stents and decreased diameter stenosis from 80 +/- 13% to 44 +/- 11% (p <0.001). Adjunctive balloon angioplasty further reduced diameter stenosis to 13 +/- 13% (p <0.001). In 13 patients with 21 stents, serial intravascular ultrasound imaging revealed a reduction of plaque area within the stent by 34 +/- 22% (from 4.2 +/- 1.8 mm2 to 2.7 +/- 1.1 mm2) after ELCA and a reduction by 65 +/- 16% (to 1.5 +/- 0.7 mm2) after balloon angioplasty (p <0.01). There were 4 patients with an increase of creatine kinase levels, 8 patients with major dissections (in 7 patients they were related to adjunctive balloon angioplasty), 1 patient with distal embolization, 2 with minor perforations, and 1 patient with stent dislocation. Reintervention during hospitalization was necessary in 3 patients. ELCA is an efficient and safe technique to debulk tissue in restenotic lesions and total occlusions within stents. The incidence of procedure related complications was low.

Acute and long-term outcome after Palmaz-Schatz stenting: analysis from the New Approaches to Coronary Intervention (NACI) registry

The randomized Stent Restenosis Study (STRESS) and Belgium Netherlands Stent (Benestent) trials established that elective use of Palmaz-Schatz stents (PSSs) in native coronary arteries with de novo lesions is associated with increased procedural success and reduced restenosis. However there are other clinical indications for which stents are commonly used (unplanned use, vein grafts, restenosis lesions) that are not addressed in these studies. From 1990-1992, 688 lesions in 628 patients were treated with PSSs in the New Approaches to Coronary Intervention (NACI) registry. Angiographic core laboratory readings were available for 543 patients (595 lesions, of which 106 were stented for unplanned indications, 239 were in saphenous vein bypass grafts, and 296 were previously treated). The cohort of patients in whom stents were placed for unplanned indications had more women, current smokers, and had a higher incidence of recent myocardial infarction (MI). Patients who underwent stenting of saphenous vein grafts were older, had a higher incidence of diabetes mellitus, unstable angina, prior MI, and congestive heart failure. Lesion success was similar in all cohorts (98%), but procedural success was significantly higher for planned stenting (96% vs 87%; p < 0.01). Predictors of adverse events in-hospital were presence of a significant left main stenosis and stenting for unplanned indication. The incidence of target lesion revascularization by 30 days was significantly higher for patients undergoing unplanned stenting due to a higher risk for stent thrombosis. Recent MI, stenting in native lesion, and small postprocedural minimum lumen diameter independently predicted target lesion revascularization at 30 days. Independent predictors of death, Q-wave myocardial infarction, or target lesion revascularization at 1 year included severe concomitant disease, high risk for surgery, left main disease, stenting in the left main coronary artery, and low postprocedure minimum lumen diameter.

Frequency and predictors of major in-hospital ischemic complications after planned and unplanned new-device angioplasty from the New Approaches to Coronary Intervention (NACI) registry

The purpose of this study was to determine the frequency and predictors of major in-hospital ischemic complications after planned and unplanned procedures with new angioplasty devices from the New Approaches to Coronary Intervention (NACI) registry. The NACI registry is a multicenter, voluntary reporting of consecutive patients undergoing new-device angioplasty procedures using atherectomy catheters, stents, or lasers. This registry affords the opportunity to evaluate the performance of new angioplasty devices during elective and urgent circumstances. The study population consisted of 3,340 patients with 3,733 lesions (2,921 in native coronary arteries and 812 in saphenous vein grafts [SVGs], who were treated with new devices over a 3.5-year period and had their angiograms analyzed independently at a central angiographic core laboratory. Their in-hospital course and multivariate predictors of the complications in planned and unplanned procedures, further divided into native and SVG lesions, were evaluated. In 82.2% of native coronary artery lesions and 96.9% of SVG lesions, the procedure with a device had been planned due to unfavorable lesion characteristics for PTCA. In the remaining lesions, device use was unplanned, and was performed mainly to treat a suboptimal result (59-80.4%) after percutaneous transluminal coronary angioplasty (PTCA), and less frequently after important complications of PTCA including abrupt closure and PTCA failure. In native artery cohort, major in-hospital ischemic complications (death, Q-wave myocardial infarction [MI], or emergency coronary artery bypass surgery) occurred in 2.7% of the planned and 9.9% of the unplanned procedures (p < 0.001), whereas in SVG such complications occurred in 3.6% of the planned and 8.7% of unplanned procedures (p = 0.21). Multivariate analysis revealed several predictors of major ischemic complications from planned native coronary artery device use: post-MI angina (odds ratio = 2.83); severe concomitant noncardiac disease (odds ratio = 2.5); multivessel disease (odds ratio = 1.75); and de novo lesions (odds ratio = 2.3). Multivariate predictors of major complications in unplanned native coronary artery procedures included high surgical risk (odds ratio = 3.08), and tortuous lesion (odds ratio = 2.41). In SVG lesions, the independent predictors of major complications for planned procedures included age (odds ratio = 1.09), high surgical risk (odds ratio = 4.34), and thrombus (odds ratio = 2.62). In native and SVG lesions, rates of major complications of planned procedures was acceptable (2.7-3.67%), but unplanned use of a new device was associated with a significantly higher rate of in-hospital complications (approximately 9%). Multivariate predictors for major ischemic complications included both clinical and lesion characteristics, and differed for native versus SVG lesions, as well as for planned versus unplanned procedures.

High-speed rotational atherectomy of human coronary stenoses: acute and one-year outcomes from the New Approaches to Coronary Intervention (NACI) registry

High-speed rotational atherectomy (RA) is a new percutaneous procedure for treatment of coronary stenoses that operates by the unique mechanism of plaque abrasion. This article reports acute (in-hospital) outcomes and 1-year follow-up in a large cohort of patients treated with this device by NACI investigators. A total of 525 patients with 670 lesions treated with RA form the substrate of this report. Patients tended to be older (mean age 64.8 years) than those in previously reported series of percutaneous transluminal coronary angioplasty (PTCA), with more extensive disease and more complex lesions. Calcification was present in 54% of lesions, and eccentricity in 41%. Balloon angioplasty postdilation was performed after RA in 88% of cases. Angiographic and procedural success (angiographic success without death, Q-wave myocardial infarction [MI] or emergency coronary artery bypass graft [CABG] surgery) rates were 89% and 88%, respectively. Acute in-hospital events included 4 deaths (1%) and 1 emergency CABG surgery (0.4%). MI occurred in 6% of patients, consisting predominantly of non-Q-wave MI (5%). After RA, angiographic complications included coronary dissection (12%), abrupt closure (5%), side branch occlusion (3%), and distal embolization (3%). Most of these were resolved after postdilation except for coronary dissection, which was present in 15% of lesions treated. Mean length of stay was 3 days. At 1-year follow-up, 27% of patients required target lesion revascularization and 30% had experienced death, Q-wave MI, or target lesion revascularization. Preprocedural characteristics that independently predicted 1-year death, Q-wave MI, or target lesion revascularization were male gender, high risk for surgery, target lesions that were proximal to or in bifurcations, eccentric, long, or highly stenosed. RA, even when applied to lesions of traditionally unfavorable morphology, appears to provide reasonable procedural and angiographic success rates. Restenosis and progression of disease contribute to subsequent clinical and procedural events.

Influence of gender on in-hospital clinical and angiographic outcomes and on one-year follow-up in the New Approaches to Coronary Intervention (NACI) registry

Higher complication rates and lower success rates for treatment of women compared with men have been reported in prior studies of coronary angioplasty and in most early reports of outcome with new coronary interventional devices. In multivariate analysis this has been attributed largely to older age and other unfavorable clinical characteristics. These results are reflected in the current guidelines for coronary angioplasty. Women in prior studies have also had different distributions of vessel and lesion characteristics, but the influence of these differences on the outcome of new-device interventions have not been adequately evaluated. This article evaluates the influence of gender on clinical and angiographic characteristics, interventional procedure and complications, angiographic success, and clinical outcomes at hospital discharge and 1-year follow-up, as observed in the New Approaches to Coronary Intervention (NACI) registry. The NACI registry methodology has been reported in detail elsewhere in this supplement. This study focuses on the 90% of patients-975 women and 1,880 men-who had planned procedures with a single new device and also had angiographic core laboratory readings. Women compared with men were older, had more recent onset of coronary ischemic pain that was more severe and unstable, and had more frequent histories of other adverse clinical conditions. The distributions of several but not all angiographic characteristics before intervention were considered more favorable to angioplasty outcome in women. Differences were observed in device use and procedure staging. Angiographically determined average gain in lumen diameter after new-device intervention, with or without balloon angioplasty, was significantly less in women (1.38 mm) than in men (1.53 mm; p < 0.001); this 0.15 mm difference is consistent with the 0.16-mm smaller reference vessel lumen diameter of women. However, final percent diameter stenoses and TIMI flow and lesion compliance characteristics were similar. Among procedural complications, only treatment for hypotension, blood transfusion, and vascular repair occurred more often in women. More women than men were clinically unstable (2.1% vs 1.1%) or went directly to emergent coronary artery bypass graft surgery (CABG; 1.2% vs 0.6%) on leaving the interventional laboratory. However, in-hospital death (1.4% vs 1.1%), Q-wave myocardial infarction (MI) (0.9% vs 1.1%), and emergent CABG (1.5% vs 1.0%, for women and men, respectively) were not significantly different. Nonemergent CABG was more frequent in women (1.8% vs 0.9%; p < 0.05) and length of hospital stay after device intervention was longer (4.4 days vs 3.8 days in men; p < 0.01). In both univariate and multivariate analyses gender did not emerge as a significant variable in relation to the combined endpoint, death, Q-wave MI, or emergent CABG at hospital discharge. At 1-year follow-up more women than men reported improvement in angina (70% vs 62%) and fewer women than men had had repeat revascularization (32% vs 36%). Similar proportions were alive and free of angina, Q-wave MI and repeat revascularization (46% of women vs 45% of men). Although several procedure-related complications were more frequent in women than men after coronary interventions with new devices, no important disadvantages were observed for women in the rates of major clinical events at hospital discharge and at 1-year clinical follow-up. Additional studies are needed to evaluate the complex interplay of clinical, vessel, and lesion characteristics on success and complications of specific interventional techniques and to determine whether gender, per se, is a risk factor and whether gender specific interventional strategies may be beneficial.

Directional coronary atherectomy (DCA): a report from the New Approaches to Coronary Intervention (NACI) registry

Directional coronary atherectomy (DCA) with the Simpson coronary atherocath seeks to debulk rather than simply displace obstructive tissue and is a means of enlarging the stenotic coronary lumen. This report from the New Approaches to Coronary Intervention (NACI) registry describes the experience of 1,196 patients who underwent DCA as the sole treatment for either native vessel or vein graft lesions. Device success (post-DCA residual stenosis <50% and > or =20% improvement) was achieved in 87.8%, with a lesion success rate (postprocedural residual stenosis <50% and > or =20% improvement) of 94.0%. The mean resultant stenosis after all interventions (by core laboratory) was 19%. Significant in-hospital complications occurred in 2.8% of patients with DCA attempts, including death 0.6%, Q-wave myocardial infarction (MI) 1.5%, and emergent coronary artery bypass graft surgery (CABG) 2.8%. At 1-year follow-up, cumulative mortality was 3.6%, with repeat revascularization in 28% (repeat percutaneous transluminal coronary angioplasty, 20.1%; CABG, 10.6%). This reflected percutaneous or surgical revascularization of the original lesion (target lesion revascularization) in 22.6% of patients. Subgroup analysis showed a lower lesion success rate and an increased complication rate for unplanned use, vein graft treatment, and treatment of a de novo (vs a restenotic) lesion. Multivariate analysis shows that diabetes mellitus, unstable angina, treatment of a restenotic lesion, and greater residual stenosis after the initial procedure were independent predictors of the composite endpoint of death/Q-wave MI/target lesion revascularization by 1-year follow-up. Among these generally favorable acute and 1-year results, the NACI directional atherectomy data confirm the "bigger is better" hypothesis: that lesions with a lower residual stenosis after a successful procedure had significantly fewer target lesion revascularizations between 30 days and 1 year, with no increase in major adverse events.

Problems in the evaluation of new devices for coronary intervention: what have we learned since 1989?

The objectives of this study are to review the problems associated with the evaluation of new devices, the progress made in that evaluation process since 1989, and the role played by the New Approaches to Coronary Intervention (NACI) registry. In 1988-1989, the first wave of new coronary devices (stents, atherectomy, laser catheters) were entering clinical investigation. It seemed unlikely that the small manufacturer-run registries used to gain approval for earlier balloon catheters would be adequate to evaluate the host of complex new devices, each of which might be used for a restricted set of anatomic indications. Moreover, the wide range of arbitrary definitions then in use for fundamental outcomes (such as success, complication, and restenosis), effectively precluded meaningful device-to-device comparisons. Against this backdrop, the NACI registry was formed with National Heart, Lung, and Blood Institute funding to provide an independent and standardized evaluation of the first 8 new devices under evaluation in the United States, across the broad range of their application. The registry employed a unique modular form set to track the sequence of events during complex cases in which serial new devices and balloon angioplasty might be used, either in a planned way, or an unplanned way (to treat complications or suboptimal results). Outcomes were subjected to standardized criteria for (1) the reason for device use (planned, unplanned); (2) success (device, lesion, and procedural success); (3) complications (a) major (death, Q-wave myocardial infarction, and emergency coronary artery bypass grafting); or (b) other (groin complications, non-wave myocardial infarction, etc.); and (4) clinical restenosis (any subsequent revascularization, target lesion revascularization). Separate funding for an angiographic core laboratory was obtained in 1992, which analyzed 3,936 (88.9%) of the 4,429 films obtained on patients enrolled between November 1990 and March 1994. The NACI registry has addressed a broad range of problems inherent in the evaluation of new devices for coronary intervention. Whereas the approval process has moved progressively towards randomized clinical trials (and away from registries), the NACI registry offers a unique view of current practice, outside the narrow scope of the limited number of randomized trials that have been performed to date. This article shows, however, that we have learned about more than the devices themselves since 1989-we have also learned about the importance of knowing the reason for device use, using precise definitions of endpoint variables, understanding the financial and reimbursement ramifications of new device trials, and upholding strict investigator ethics during the conduct of such evaluations.

Abrupt vessel closure: changing importance, management, and consequences

Percutaneous coronary interventions have been performed for 20 years. Despite the success and progress of these interventions, abrupt vessel closure has been a dramatic adverse event of coronary interventions. Closure has frequently led to the major complications of death, myocardial infarction, and emergency coronary artery bypass. Because of the fear of this adverse event and its subsequent complications, the applicability of coronary interventions is sometimes limited. The pathologic characteristics of abrupt vessel closure have been recognized as predominantly caused by dissection, with vessel recoil and thrombus formation playing important secondary roles. The recognition of the lesions at risk for abrupt vessel closure has led to a strategy of lesion-specific device therapy to reduce complications. Similarly the role of antiplatelet and antithrombotic therapies have reduced complications. The earliest methods of dealing with abrupt closure was emergency coronary artery bypass surgery with significant rates of morbidity and mortality. With the advent of second-generation devices and techniques, particularly stents, the management of abrupt vessel closure has been simplified and alternatives to emergency coronary bypass are more available. This article will review the history and current status of the prevention and management of abrupt vessel closure and demonstrate that anticipation and management of this complication have been facilitated with reduction of subsequent complications and increased applicability of coronary interventions.

Revascularization of patients with coronary artery disease: the interventional cardiologist's perspective

In the majority of patients with chronic coronary artery disease, treatment is aimed at palliation or prolongation of disease-free intervals and consists of either pharmacologic therapy or coronary revascularization. As a result of continuous refinements and improvements in both surgical and catheter-based revascularization techniques, modalities, and adjunctive pharmacologic therapy, an increasing number of patients may benefit from coronary revascularization. This also engenders difficult choices for the physicians responsible for selecting the most appropriate treatment. To achieve and provide optimal patient care an open and principled discussion with all parties involved is mandatory and must be based on the integration of clinical experience and data from both basic and clinical research. The purpose of this article is to provide the interventional cardiologist's view on the treatment of patients with atherosclerotic coronary artery disease.

Results of directional coronary atherectomy in Northern New England. Northern New England Cardiovascular Disease Study Group

The role of directional coronary atherectomy (DCA) in interventional cardiology remains uncertain. We report the Northern New England regional experience with DCA from 1991 to 1994. Data were collected on 11,178 patients having had an intervention on a single lesion in a single vessel (798 DCAs; 10,380 percutaneous transluminal angioplasties [PTCA]). The use of DCA increased from 1.8% of interventions in 1991 to 10% in 1994. Compared with PTCA, DCA patients were younger, more often men, had more 1-vessel disease and more coronary artery bypass surgery (CABG). DCA was more often used in the left anterior descending artery, in vein grafts, for restenoses, for subtotal occlusions, and with type A lesions. Angiographic success (96.7%) and clinical success (93%) were good. Adverse events were rare: mortality 0.9%, emergent CABG 2.2%, nonfatal myocardial infarction 2.8%. After adjusting for case-mix, there was no difference between DCA and PTCA for in-hospital mortality (odds ratio [OR] = 1.03, 95% confidence interval [CI] 0.44 to 2.43, p = 0.95) or need for emergent CABG (OR = 1.27, 95% CI 0.77 to 2.10, p = 0.34). Atherectomy patients were more likely to have a nonfatal myocardial infarction (OR = 2.0, 95% CI 1.26 to 3.20, p <0.01), to sustain an injury to the femoral or brachial artery (OR = 2.89, 95% CI 1.52 to 5.51, p <0.01), and to have a clinically successful procedure (OR = 1.37, 95% CI 1.01 to 1.88, p = 0.05). Our results support the relative safety and effectiveness of DCA as its use disseminated into the region.

Comparison of balloon angioplasty versus debulking devices versus stenting in right coronary ostial lesions

Angioplasty of aorto-ostial stenosis is associated with lower procedural success and a higher complication rate. The aim of the present study was to compare the acute and long-term results of balloon and new device angioplasty in 110 consecutive patients with right coronary ostial lesions. Patients were divided into 3 groups according to the angioplasty device used: group I (balloon only, n = 26), group II (debulking devices including excimer laser, directional and rotational atherectomy, n = 26), group III (stent, n = 58). Procedural success was highest in group III (96%) followed by group I (88%), and group II (77%). In-hospital complications were similar among the groups (p = NS). Patients in group III achieved the highest acute gain (2.61 mm) followed by groups II (1.92 mm), and I (1.39 mm, p <0.05). During follow up, target lesion revascularization and/or bypass surgery was required in 24% of patients in group III compared with 47% and 40% in groups I and II, respectively (p <0.05). Cardiac-event free survival was highest in the stent group (74%, p <0.005) and was similar between the balloon (39%) and debulking device groups (45%). Thus, among the currently available technologies, stenting of right coronary ostial lesions appears to provide excellent angiographic and long-term results.

Percutaneous treatment of protected and unprotected left main coronary stenoses with new devices: immediate angiographic results and intermediate-term follow-up

OBJECTIVES

We sought to evaluate the immediate angiographic results and intermediate-term follow-up after percutaneous treatment of left main coronary stenoses in the new device era.

BACKGROUND

Historically, balloon angioplasty of left main coronary stenoses has been associated with high procedural morbidity and poor long-term results. It is not clear whether new devices are more effective in this anatomic setting.

METHODS

Between July 1993 and July 1995, we performed initial left main coronary interventions on 46 patients (mean age 67 +/- 12 years, 26% women). Quantitative angiography was available for 42 of 46 interventions, and clinical follow-up was obtained for all patients at 1 month, 6 months and 1 year after initial revascularization.

RESULTS

Most interventions (42 of 46) were performed in patients with "protected" coronary stenoses to the left coronary system owing to the presence of one or more patent left main coronary grafts. Seventy-seven percent of screened patients were deemed unsuitable for repeat coronary artery bypass surgery. Procedures performed included stenting in 73% of patients (alone in 30% and after rotational atherectomy in 43%), rotational atherectomy in 58% (alone in 15% and before stenting in 43%), directional atherectomy in 4% and angioplasty alone in 7%. Initial procedural success was achieved in all interventions, with no deaths, myocardial infarctions (creatine kinase, MB fraction > 50 IU/liter) or emergent bypass surgery. Follow-up data to date (median duration 9 months, range 6 to 19) demonstrate a 98% overall survival rate and a 6-month event-free survival rate of 78% (six target vessel revascularizations [TVRs], four non-TVRs).

CONCLUSIONS

Treatment of protected left main coronary artery stenoses can be accomplished safely and effectively with new device technology. Intermediate-term follow-up demonstrates an acceptably low rate of death, myocardial infarction or repeat revascularization at 6 months and 1 year.

Evaluating the cost of therapy for restenosis: considerations for brachytherapy

Costs have become increasingly important in medicine in recent years as demand for services has outstripped readily available resources. Clinical microeconomics offers an approach to understanding cost and outcomes in an environment of economic scarcity. In this article the types of costs and methods for determining cost are presented. In addition, methods for assessing outcome and outcome in relation to cost are developed. Restenosis after coronary angioplasty is a prime example of a clinical problem requiring economic evaluation. This is because it results in little serious morbidity except for recurrent chest pain, but it has serious economic consequences which occur some time after the original angioplasty. This makes the economic assessment of restenosis complicated. The application of health care microeconomic principles to brachytherapy for restenosis in the coronary arteries is presented.

Salvage atherectomy: using retrieved tissue to determine the etiology of acute closure

Directional coronary atherectomy was successfully performed in the mid-left anterior descending artery at the site of failed balloon angioplasty. We presumed that intracoronary thrombus had resulted in acute vessel closure following balloon angioplasty, due to the angiographic appearance of the lesion and the clinical situation. However, examination of the extracted specimen from the atherectomy device revealed predominantly atheromatous tissue with minimal thrombus.

Continued benefit of coronary stenting versus balloon angioplasty: one-year clinical follow-up of Benestent trial. Benestent Study Group

OBJECTIVES

This study sought to determine the 1-year clinical follow-up of patients included in the Benestent trial.

BACKGROUND

The Benestent trial is a randomized study comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in patients with stable angina and a de novo coronary artery lesion. Seven-month follow-up data have shown a decreased rate of restenosis and fewer clinical events in the stent group. It is not established whether this favorable clinical outcome is maintained for longer periods or whether coronary stenting defers restenosis and its subsequent clinical manifestations.

METHODS

To clarify this uncertainty, we updated clinical information on all but 1 of 516 patients enrolled in the Benestent trial (257 in balloon group, 259 in stent group) at least 12 months after the intervention. Major clinical events (primary clinical end point) were tabulated according to the intention to treat principle and included death, the occurrence of a cerebrovascular accident, myocardial infarction, the need for bypass surgery or a further percutaneous intervention in the previously treated lesion.

RESULTS

After 1 year, no significant differences in mortality (1.2% vs. 0.8%), stroke (0.0% vs. 0.8%), myocardial infarction (5.0% vs. 4.2%) or coronary bypass graft surgery (6.9% vs. 5.1%) were found between the stent and balloon angioplasty groups, respectively. However, the requirement for a repeat angioplasty procedure was significantly lower in the stent group (10%) than the balloon angioplasty group (21%, relative risk [RR] 0.49, 95% confidence interval [CI] 0.31 to 0.75, p = 0.001), and overall primary end points were less frequently reached by stent group patients (23.2%) than those in the balloon group (31.5%, RR 0.74, 95% CI 0.55 to 0.98, p = 0.04). No differences were found between groups with respect to functional class angina and prescribed medication at the time of follow-up.

CONCLUSIONS

These clinical follow-up data show that the benefit of elective native coronary artery stenting in patients with stable angina is maintained to at least 1 year after the procedure and results in a significantly reduced requirement for repeat intervention.

Solid-state, pulsed-wave, mid-infrared coronary laser angioplasty in de novo versus restenosis lesions: observations from a multicenter study

The following is a study of the response of de novo versus restenosis coronary lesions to pulsed-wave, mid-infrared (holmium:YAG) laser assisted angioplasty. De novo lesions contain thrombi, cholesterol, and fibrosis, whereas restenotic lesions are composed of smooth muscle cells corresponding to injury caused by preceding balloon inflations. It is not known whether the different composition affects results of treatment by laser. In a clinical multicenter study, a mid-infrared, solid-state, pulsed-wave laser (holmium:YAG, 2.1 microns wavelength, 250-600 mJ/pulse, 5 Hz) was applied for revascularization of de novo and restenosis coronary lesions. Analysis of data was undertaken to document laser success, complications, and restenosis rate and to define whether the type of lesion treated had an effect on laser success and related complications. A total of 1340 patients with 1465 stenoses presented with symptomatic coronary artery disease. Laser success was 87 and 86% in these lesions, respectively. Overall procedural success of 93% was achieved. Restenosis lesions, known to be composed of smooth muscle proliferation, needed more laser energy for ablation than de novo lesions, which contain an atherosclerotic plaque (130 +/- 123 pulses vs 109 +/- 31, p = 0.001). Procedure-related Q-wave myocardial infarction was significantly higher in patients with de novo lesions over patients with restenosis lesions (1.4 vs 0.2%, p = 0.05). With the mid-infrared, pulsed-wave, holmium:YAG laser, the composition of the target lesion affects the energy level required, as well as the procedure-related complications.

Dislocation of the rotating cutter during directional coronary atherectomy: a note of caution

Directional coronary atherectomy (DCA) has received increased attention, especially as a bail-out procedure after failed balloon angioplasty. However, this technique may also be burdened by severe pitfalls. We report a patient with a balloon-resistant left coronary artery lesion subsequently treated with DCA. Despite its over-the-wire guidance, as the rotating cutter was advanced, it deviated from its intra-housing course and intruded into the vascular wall. Dislocation of the rotating blade was due to pressure from hard plaque tissue. After having carefully pulled back the complete catheter system, a severe spasm of the left main stem occurred, which was reversed by intracoronary nitroglycerine. The final angiography showed a left coronary artery without significant, residual stenosis. The case report underscores that DCA passes must be performed under continuous fluoroscopic control, especially for balloon-resistant lesions because of the unpredictability of DCA-imminent complication.

Perfusion therapy to reduce myocardial ischemia en route to emergency coronary artery bypass grafting for failed percutaneous transluminal coronary angioplasty

Despite improvements in operator technique, catheter technology, and the development of new devices, emergency coronary artery bypass grafting (CABG) is still required in 1%-4% of attempted catheter based revascularization procedures. Patients who require such emergency CABG after failed percutaneous transluminal coronary angioplasty (PTCA) have worse acute outcomes than those undergoing elective CABG, with a higher incidence of Q wave myocardial infarction (MI) and a higher operative mortality. In patients with otherwise refractory abrupt closure, maintenance of antegrade coronary blood flow using perfusion catheters lessens the incidence of Q wave MI and lowers peak creatinine phosphokinase. Direct maintenance of coronary flow thus appears to provide more definitive control of myocardial ischemia than purely adjunctive measures, such as intra-aortic balloon pumping, cardiopulmonary support, or coronary sinus retroperfusion. Although the recent introduction of coronary stents holds great promise for definitive percutaneous reversal of abrupt closure and a dramatic decrease in the incidence of emergency CABG for failed PTCA, maintenance of antegrade flow via perfusion technology remains the cornerstone of management in reducing the perioperative mortality and morbidity of patients who still require emergency bypass surgery after failed PTCA.

Directional atherectomy of left main stenoses

Balloon angioplasty (PTCA) of left main (LM) stenoses is limited by frequent clinical restenosis. Directional coronary atherectomy (DCA) may be an effective alternative to PTCA due to its ability to achieve a greater postprocedural luminal diameter when treating bulky, eccentric plaques and aorto-ostial lesions. We analyzed the acute and long-term results following 24 DCA procedures in 22 patients with "protected" LM lesions. Acute success (residual stenosis < or = 40%, no major ischemic complications) was 88% overall, 100% in 13 planned procedures, and 73% in 11 adjunctive DCA procedures that followed suboptimal PTCA. Mean LM stenosis was reduced from 86% to 13% (P < 0.01). There were no procedural complications directly attributed to DCA. At a mean of 24 +/- 3 months, the clinical restenosis rate was 16%, survival was 100%, and event-free survival (freedom from death, MI, or repeat lesion-related interventions) was 89%. We conclude that DCA in protected LM lesions (1) can achieved excellent angiographic results with low procedural complication rates, (2) may succeed where PTCA yields suboptimal results, and (3) may provide late clinical outcomes superior to those of balloon angioplasty.

Peripheral arterial angioplasty balloons as adjuncts to percutaneous coronary revascularization

Although PTCA balloon technology has improved dramatically since the first catheters were introduced over a decade ago, some limitations remain. The largest conventional balloon size available is 4.0 mm diameter. Larger size balloons are sometimes necessary for saphenous vein graft dilatation or in very large native coronary arteries. Also, adjunctive balloon angioplasty is used frequently after atherectomy and other coronary device therapy. Current generation balloons are not always necessary in this setting, since a large lumen has already been established. Thus, it has become useful in our laboratory to use peripheral arterial angioplasty balloons for both large coronary vessel dilatation, and also for adjunctive dilatation after device use. We describe our initial experience with peripheral arterial angioplasty balloons as adjuncts to percutaneous coronary revascularization.