Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

A large-scale multicentre study of patient skin doses in interventional cardiology: dose-area product action levels and dose reference levels

For 318 patients in 8 different Belgian hospitals, the entire skin-dose distribution was mapped using a grid of 70 thermoluminescence dosimeters per patient, allowing an accurate determination of the maximum skin dose (MSD). Dose-area product (DAP) values, exposure parameters and geometry, together with procedure, patient and cardiologist characteristics, were also registered. Procedures were divided into two groups: diagnostic procedures (coronary angiography) and therapeutic procedures (dilatation, stent, combined procedures (e.g. coronary angiography + dilatation + stent)). The mean value of the MSD was 0.310 Gy for diagnostic and 0.699 Gy for therapeutic procedures. The most critical projection for receiving the MSD is the LAO90 (left anterior oblique) geometry. In 3% of cases, the MSD exceeded the 2 Gy dose threshold for deterministic effects. Action levels in terms of DAP values as the basis for a strategy for follow-up of patients for deterministic radiation skin effects were derived from measured MSD and cumulative DAP values. Two DAP action levels are proposed. A first DAP action level of 125 Gy cm(2) corresponding to the dose threshold of 2 Gy would imply an optional radiopathological follow-up depending on the cardiologist's decision. A second DAP action level of 250 Gy cm(2) corresponding to the 3 Gy skin dose would imply a systematic follow-up. Dose reference levels - 71.3 Gy cm(2) for diagnostic and 106.0 Gy cm(2) for therapeutic procedures - were derived from the 75 percentile of the DAP distributions. As a conclusion, we propose that total DAP is registered in patient's record file, as it can serve to improve the follow-up of patients for radiation-induced skin injuries.

Continued benefit of coronary stenting versus balloon angioplasty: five-year clinical follow-up of Benestent-I trial

OBJECTIVES

This study sought to establish whether the early favorable results in the Benestent-I randomized trial comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in 516 patients with stable angina pectoris are maintained at 5 years.

BACKGROUND

The size of the required sample was based on a 40% reduction in clinical events in the stent group. Seven months and one-year follow-up in this trial showed a decreased incidence of restenosis and clinical events in patients randomized to stent implantation.

METHODS

Data at five years were collected by outpatient visit, via telephone and via the referring cardiologist. Three patients in the stent group and one in the percutaneous transluminal coronary angioplasty (PTCA) group were lost to follow-up at five years. Major clinical events, anginal status and use of cardiac medication were recorded according to the intention to treat principle.

RESULTS

No significant differences were found in anginal status and use of cardiac medication between the two groups. In the PTCA group, 27.3% of patients underwent target lesion revascularization (TLR) versus 17.2% of patients in the stent group (p = 0.008). No significant differences in mortality (5.9% vs. 3.1%), cerebrovascular accident (0.8% vs. 1.2%), myocardial infarction (9.4% vs. 6.3%) or coronary bypass surgery (11.7% vs. 9.8%) were found between the stent and PTCA groups, respectively. At five years, the event-free survival rate (59.8% vs. 65.6%; p = 0.20) between the stent and PTCA groups no longer achieved statistical significance.

CONCLUSIONS

The original 10% absolute difference in TLR in favor of the stent group has remained unchanged at five years, emphasizing the long-term stability of the stented target site.

Assessment of coronary angiograms prior to and after treatment with abciximab, and the outcome of angioplasty in refractory unstable angina patients. Angiographic results from the CAPTURE trial

BACKGROUND

The CAPTURE study (c 7E3 A nti P latelet T herapy in U nstable Re fractory angina) was designed to assess outcome in patients with refractory angina undergoing angioplasty, receiving either abciximab or placebo.

METHODS

One thousand two hundred and sixty-five patients with refractory unstable angina, defined as recurrent myocardial ischaemia despite medical treatment including heparin and nitrates were enrolled. After angiography, patients received an infusion of abciximab or placebo over 18-24 h preceding angioplasty, continuing until 1 h after the procedure. In 1197 patients undergoing angioplasty the angiographic committee centrally reviewed the baseline as well as the procedural angiograms. Coronary flow and lesion characteristics were assessed in the baseline angiogram as well as before intervention. Angiographic outcome, reason for failure as well as complications were assessed after angioplasty.

RESULTS

At 30 days follow-up, patients receiving abciximab (n=595) compared with placebo (n=602) had a 30% reduction in the composite primary end-point death, myocardial infarction or urgent (re)intervention: 10.8% vs 15.4% (P=0.017). Baseline demographics were identical in the angiogram available group compared with the total study group. At 30 days, the non-angiogram available patients showed a higher incidence of events compared to those in whom the angiogram was reviewed: 19.4 vs 13.1% (P=ns). Lesion characteristics and coronary flow were not different at baseline between the placebo and abciximab groups. A primary end-point was reached in 9.6% of both placebo and abciximab patients with type A or B(1)lesions, in 17.0% vs 12.0% with type B(2)lesions, and in 19.1% vs 11.5% with type >B(2)or C lesions. Sixty-one percent of placebo and abciximab patients had TIMI 3 flow at baseline angiography. Pre-angioplasty TIMI 3 flow was observed in 69% and 72% respectively. The thrombus was resolved between the angiograms in 22% and 43% respectively, in the placebo and abciximab groups (P=0. 033). Angiographic success of the procedure was achieved in 88% and 94% in the placebo and abciximab patients, respectively (P<0.001). Stents were implanted in the ischaemia-related artery in 56 and 60 patients, respectively. However, failure of the stent procedure was more frequent in the placebo group than in the abciximab group, nine vs no patients (P=0.003).

CONCLUSION

More frequent thrombus resolution was observed and a higher angiographic success rate was achieved in patients treated with abciximab before and during angioplasty compared with placebo. Patients with complex lesions as the underlying pathology reached fewer end-points if treated with abciximab before and during angioplasty.

Audit and quality control in angioplasty in Europe: procedural results of the AQUA Study 1997: assessment of 250 randomly selected coronary interventions performed in 25 centres of five European countries. AQUA Study Group, Nucleus Clinical Issues, Working Group Coronary Circulation, of the European Society of Cardiology

AIMS

Percutaneous transluminal coronary angioplasty (PTCA) has become the most widely used major intervention in western medicine. However, there is disparate use of this technique among different European countries and the U.S.A. In an attempt at quality assurance, the working group Coronary Circulation of the European Society of Cardiology has carried out a study on appropriateness, necessity, and performance of PTCA in Europe. The present paper reports on the procedural results of this survey.

METHODS

In a multicentre case-control study in Europe, 750 patients (544 men, 206 women) with documented vascular disease of the From the countries participating in the European Registry of Coronary Intervention, the three countries with the highest absolute PTCA volume (Germany, France, and the United Kingdom) and two randomly selected countries (Belgium and Italy) were chosen for investigation. In these countries, five centres were selected at random according to the following criteria: one centre with >1000, three centres with 300-1000, and one centre with <300 procedures per year. In each of these, 10 cases from the first half of 1997 were randomly identified and all pertinent documentation was collected.

RESULTS

In 250 cases, 325 stenoses were addressed as target lesions. Single vessel disease was present in 41%. History included stable angina in 49%, unstable angina in 32%, atypical chest pain in 6%, no anginal pain in 12%, and acute/subacute myocardial infarction in 13%. The percentage of patients with either positive stress test and/or unstable angina, acute/subacute infarction, previous infarction (within 6 months) or coronary revascularization amounted to 98%. Single vessel intervention accounted for 90%. In 41% balloon-only angioplasty was performed and in 54% at least one stent was implanted with considerable variation among countries. The use of other new devices amounted to only 3%. In 92%, the operators documented a successful procedure. Major complications (myocardial infarction, emergency bypass surgery, or death) were found in 4.8%.

CONCLUSIONS

Based on scrutinized hospital and operator data, the present study revealed a satisfactorily high percentage of justifiable indications, an adequate procedural success rate, and an acceptably low complication rate. Further analysis by an expert panel will address appropriateness, necessity, and procedural performance of the individual cases.

Interventional cardiology in Europe 1994. Working Group Coronary Circulation of the European Society of Cardiology

The working group Coronary Circulation of the European Society of Cardiology conducts an annual survey of cardiac interventions in Europe with the support of the national societies of cardiology. A detailed questionnaire about cardiac interventions performed during 1994 was mailed to all members of the European Society of Cardiology. Incomplete or absent data from eight national members precluded their inclusion in the final analysis. Thus, this report summarizes the cardiac interventions performed during 1994 in 29 of 37 members of the European Society of Cardiology, representing a total population of approximately 490 million inhabitants.

CORONARY ANGIOGRAPHY

A total of 922,687 coronary angiograms were reported during 1994, representing an increase of 22% compared with 1993 and of 35% compared with 1992. The mean incidence of coronary angiograms was 1881/10(6) inhabitants, ranging from 4417/10(6) inhabitants in Germany to 35/10(6) inhabitants in Romania, Germany, France, Great Britain, and Italy with 50% of the European population performed 73% of all cardiac interventions.

CORONARY ANGIOPLASTY

During 1994, a total of 224,722 coronary angioplasty (PTCA) procedures were reported in Europe, an increase of 22% compared with 1993 and of 52% compared with 1992. Adjusted per capita, the mean incidence of coronary angioplasty was 458/10(6) inhabitants, ranging from 1091/10(6) inhabitants in Germany to 6/10(6) inhabitants in Romania. On average, the ratio PTCA per coronary angiogram was 0.24, ranging from 0.37 in the Netherlands to 0.06 in Cyprus. Ad hoc PTCA accounted for 22% of all PTCA cases. The majority (81%) of PTCAs were restricted to a single vessel. Major complications were reported in 2% of patients undergoing PTCA, including death (0.3%), myocardial infarction (1.0%) and need for emergency coronary artery bypass grafting (0.7%).

CORONARY STENTING

Coronary stents were utilized in 21,599 coronary interventions during 1994, an increase of 235% compared with 1993 and thus representing the fastest growth in interventional cardiology. The number of European countries employing stents during coronary angioplasty grew from 14 during 1993 to 24 during 1994. Elective use (38%) became the most frequent indication for coronary stenting during 1994, replacing bail-out stenting as the primary indication during 1993.

OTHER NEW DEVICES

Other new interventional therapeutic devices were employed in 8827 cases. Only the Rotablator was used more frequently during 1994 as compared with 1993. All other new therapeutic devices showed a decline. Coronary ultrasound was utilized in 3032 interventions and coronary angioscopy in 304 cases during 1994. NON-CORONARY INTERVENTIONS: Valvuloplasty remained the most frequent non-coronary intervention in Europe during 1994 with a total of 2622 mitral. 609 pulmonary and 506 aortic valvuloplasties.

CATHETERIZATION FACILITIES

The number of facilities per 10(6) inhabitants performing invasive cardiac procedures in Europe during 1994 ranged from 7.7 in Iceland to 0.2 in Romania (European mean 2.9). The number of trained operators per 10(6) inhabitants ranged from 24 in Germany to 0.4 in Romania (European mean 10). During 1994, a mean of 701 coronary angiograms and 170 PTCAs were performed per catheterization facility in Europe (range: 1052 coronary angiograms and 293 PTCAs per facility in Norway to 218 coronary angiograms and 37 PTCAs per facility in Romania).

CONCLUSIONS

The number of both coronary angiograms and coronary angioplasties continues to grow at an annual rate of approximately 20% in Europe. There is a wide range in the amount of revascularization procedures performed between western and eastern European countries. However, countries with the lowest numbers of coronary angiograms and coronary angioplasties, e.g. Romania, also show the fastest annual growth. About one quarter of all patients undergoing coronary angiography are subsequently revascularized by coronary angioplasty. (ABSTRACT TRUN

Interventional cardiology in Europe 1993. Working Group on Coronary Circulation of the European Society of Cardiology

An annual survey on cardiac interventions in Europe is performed by the working group on Coronary Circulation of the European Society of Cardiology with the help of the national societies of cardiology. A questionnaire about cardiac interventions in 1993 was mailed to a representative of the national societies of 35 members of the European Society of Cardiology. The data collection of coronary interventions was delayed by slow backreporting and from 10 of the 35 national members data were missing or grossly incomplete. They were excluded from the analysis.

CORONARY ANGIOGRAPHY

A total of 756,822 coronary angiograms were reported resulting in an incidence of 1146 +/- 1024 per 10(6) inhabitants, ranging from 24 (Romania) to 3499 (Germany). This represents an increase of 12% compared to 1992. Germany (279,882 cases), France (157,237), the United Kingdom (77,000), Italy (44,934) and Spain (37,591) registered 79% of all the coronary angiograms performed.

PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

A total of 183,728 percutaneous transluminal coronary angioplasty cases were reported in 1993, 24% more than in 1992. On average, they accounted for 18 +/- 7% (range 8 (Romania) to 35% (Sweden) of the coronary angiograms. Most of these percutaneous transluminal coronary angioplasties (82%) were confined to a single vessel. In 13% only, percutaneous transluminal coronary angioplasty took place immediately after the diagnostic study. Adjusted per capita. Germany ranks first with 873 percutaneous transluminal coronary angioplasties per 10(6) inhabitants, followed by France (737), Holland (725), Belgium (713), and Switzerland (665). The European mean of percutaneous transluminal coronary angioplasties per 10(6) inhabitants was 270 +/- 279, representing an increase of 14% compared with 1992. A major in-hospital complication was reported in 3.8% of the patients undergoing percutaneous transluminal coronary angioplasty: 0.6% hospital deaths, 1.5% emergency coronary artery bypass grafting, and 1.7% myocardial infarctions.

NEW DEVICES

In 1993 stents were implanted in 6444 patients (3.5% of all percutaneous transluminal coronary angioplasty patients), equally distributed between bail-out situations (53%) and elective procedures. The 14 stent implanting countries showed a mean increase in incidence of coronary stenting of 53% compared with 1992. Other interventional devices were applied in 7045 cases, 3.8% of all percutaneous transluminal coronary angioplasty cases. Coronary ultrasound (2194 cases) and coronary angioscopy (380 cases) were performed infrequently. NON-CORONARY INTERVENTIONS: Valvuloplasties were most frequently performed non-coronary interventions European countries performed more than 300 valvuloplasties each in 1993. Most of them were mitral valvuloplasties in southern countries.

CONCLUSIONS

Although partial backreporting might conclusions, several findings of this survey are noteworthy for the participating countries: The number of percutaneous taneous transluminal coronary angioplasties is universally increasing. There is an extremely wide range of coronary angiography and percutaneous translumina, coronary angioplasties performed per population. The most common additional procedure is a stent implantation while other new devices are only rarely applied. Mitral valvuloplasty is the most frequently performed non-coronary intervention.

Heparin-coated Palmaz-Schatz stents in human coronary arteries. Early outcome of the Benestent-II Pilot Study

BACKGROUND

The purpose of the Benestent-II Pilot Study was to evaluate the safety of delaying and eliminating anticoagulant therapy in patients receiving a heparin-coated stent in conjunction with antiplatelet drugs.

METHODS AND RESULTS

The study consisted of three initial phases (I, II, III) during which resumption of heparin therapy after sheath removal was progressively deferred by 6, 12, and 36 hours. In phase IV, coumadin and heparin were replaced by 250 mg ticlopidine and 100 mg aspirin. Of the 207 patients with stable angina pectoris and a de novo lesion in whom heparin-coated stent implantation was attempted, implantation was successful in 202 patients (98%). Stent thrombosis did not occur during all four phases, and the overall clinical success rate at discharge was 99%. Bleeding complications requiring blood transfusion or surgery fell from 7.9% in phase I to 5.9%, 4%, and 0% in the three following phases. Hospital stay was 7.4, 6.1, 7.2, and 3.1 days for the consecutive phases. The restenosis rate for the combined four phases was 13% (15% in phase I, 20% in phase II, 11% in phase III, and 6% in phase IV). The overall rate of reintervention for the four phases was 8.9%. At 6 months, 84%, 75%, 94%, and 92% of the patients of phases I to IV, respectively, were event free. For the four phases, the event-free rate was 86%, which compares favorably with the rate observed in the Benestent-I study (80%; relative risk, 0.68 [0.45 to 1.04]).

CONCLUSIONS

The implantation of stents coated with polyamine and end-point-attached heparin in stable patients with one significant de novo coronary lesion is well tolerated, is associated with no (sub)acute stent thrombosis, and results in a favorable event-free survival after 6 months.

Clinical and angiographic outcome following implantation of the new Less Shortening Wallstent in aortocoronary vein grafts: introduction of a second generation stent in the clinical arena

One of the factors felt to have contributed to the high rate of stent occlusion in the European registry of the coronary Wallstent in the 1980s was the frequent deployment of more than one stent to cover the target lesion. This resulted from a high degree of shortening of the Wallstent upon expansion. To overcome this limitation the design of the Wallstent was modified to reduce the degree of shortening. We report the results of a study of the first patients to undergo implantation of the new Less Shortening Wallstent. Thirty-five Wallstents were electively deployed in aortocoronary vein grafts in 29 patients. Stent deployment was successful in 35 of 36 attempts in 30 lesions. In five of the 30 lesions, a second stent was required to cover the proximal portion of the lesion. Angiographic success (< 50% residual diameter stenosis as determined by off-line quantitative coronary angiography) was achieved in all 29 patients. During the in-hospital phase, no major adverse cardiac event occurred (reintervention, re-CABG, myocardial infarction, or death) and five patients had hemorrhagic complications. Following hospital discharge, one patient had a subacute stent occlusion associated with symptoms and elevated cardiac enzymes at 11 days, another patient had symptoms and elevated cardiac enzymes (CK 300 U/I) at 22 days with a patent stent, five patients required balloon angioplasty within the 6 month follow-up period (four for restenosis and one for stent occlusion), one patient underwent re-CABG for a native artery stenosis distal to the anastomosis of the patent stented vein graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized comparison of rescue angioplasty with conservative management of patients with early failure of thrombolysis for acute anterior myocardial infarction

BACKGROUND

When used in the setting of acute myocardial infarction, intravenous thrombolytic agents fail to achieve early infarct artery patency in 15% to 50% of patients. We tested the hypothesis that immediate balloon angioplasty applied to patients with failed early reperfusion would improve left ventricular function and clinical outcome at 30 days compared with conservative management alone.

METHODS AND RESULTS

One hundred fifty-one patients with first anterior wall infarction treated with any accepted intravenous thrombolytic regimen and angiographically demonstrated to have an occluded infarct vessel within 8 hours of chest pain onset were randomized to aspirin, heparin, and coronary vasodilators (conservative therapy) or to this therapy and balloon angioplasty supplemented by further thrombolytic therapy as needed. Left ventricular function was assessed using multiple-gated equilibrium radionuclide technique to determine ejection fraction, and adverse clinical outcome was assessed evaluating death, ventricular tachycardia, and class III or IV heart failure at 30 days. Seventy-three patients were randomized to conservative therapy and 78 to angioplasty. The two groups were well balanced for patient age (59 +/- 11 years), sex (82% were male), and time to randomization (4.5 +/- 1.9 hours). Angioplasty was technically successful in 72 of 78 randomized patients (92%). Two patients randomized to conservative therapy crossed over to angioplasty within 72 hours. Resting 30-day ejection fraction was 40 +/- 11% in the angioplasty group and 39 +/- 12% in the conservative group (P = .49), but ejection fraction with exercise was 43 +/- 15% and 38 +/- 13% for the angioplasty and conservatively treated groups, respectively (P = .04). Adverse clinical outcomes included death in 5% and 10% (P = .18), severe heart failure in 1% and 7% (P = .11), and either death or severe heart failure in 6% and 17% (P = .05) of the angioplasty and conservatively managed groups, respectively.

CONCLUSIONS

When applied to patients with first anterior infarction, rescue angioplasty appears to be useful in the prevention of death or severe heart failure, with improvement in exercise, but not resting, ejection fraction. This strategy deserves further study and highlights the potential advantage of early mechanical restoration of infarct vessel patency when thrombolytic therapy has failed.

A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. Benestent Study Group

BACKGROUND

Balloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical outcomes as compared with standard balloon angioplasty.

METHODS

A total of 520 patients with stable angina and a single coronary-artery lesion were randomly assigned to either stent implantation (262 patients) or standard balloon angioplasty (258 patients). The primary clinical end points were death, the occurrence of a cerebrovascular accident, myocardial infarction, the need for coronary-artery bypass surgery, or a second percutaneous intervention involving the previously treated lesion, either at the time of the initial procedure or during the subsequent seven months. The primary angiographic end point was the minimal luminal diameter at follow-up, as determined by quantitative coronary angiography.

RESULTS

After exclusions, 52 patients in the stent group (20 percent) and 76 patients in the angioplasty group (30 percent) reached a primary clinical end point (relative risk, 0.68; 95 percent confidence interval, 0.50 to 0.92; P = 0.02). The difference in clinical-event rates was explained mainly by a reduced need for a second coronary angioplasty in the stent group (relative risk, 0.58; 95 percent confidence interval, 0.40 to 0.85; P = 0.005). The mean (+/- SD) minimal luminal diameters immediately after the procedure were 2.48 +/- 0.39 mm in the stent group and 2.05 +/- 0.33 mm in the angioplasty group; at follow-up, the diameters were 1.82 +/- 0.64 mm in the stent group and 1.73 +/- 0.55 mm in the angioplasty group (P = 0.09), which correspond to rates of restenosis (diameter of stenosis, > or = 50 percent) of 22 and 32 percent, respectively (P = 0.02). Peripheral vascular complications necessitating surgery, blood transfusion, or both were more frequent after stenting than after balloon angioplasty (13.5 vs. 3.1 percent, P < 0.001). The mean hospital stay was significantly longer in the stent group than in the angioplasty group (8.5 vs. 3.1 days, P < 0.001).

CONCLUSIONS

Over seven months of follow-up, the clinical and angiographic outcomes were better in patients who received a stent than in those who received standard coronary angioplasty. However, this benefit was achieved at the cost of a significantly higher risk of vascular complications at the access site and a longer hospital stay.

The use of carbon 11-labeled acetate for assessment of aerobic metabolism

Carbon 11-labeled acetate has been validated as a tracer of citric acid flux and indirectly of oxidative metabolism. 11C-labeled acetate is predominantly metabolized to 11C-labeled carbon dioxide, which clears from the heart. The myocardial 11CO2 efflux rate that can be estimated by dynamic positron emission tomographic imaging closely correlates with myocardial oxygen consumption over a wide range of flow, substrate use, and metabolic conditions. 11C-labeled acetate clearance rates are indirect indexes of oxidative metabolism. To provide absolute mass fluxes, the 11C-labeled acetate approach would require biochemical validation and configuration of a tracer kinetic model. Clinically, estimates of myocardial oxygen consumption appear to be useful in assessing tissue viability, as shown in patients after acute myocardial infarction or with chronic coronary artery disease. In non-coronary artery disease, 11C-labeled acetate may provide measurement of cardiac efficiency and be useful for monitoring therapy.

Directional atherectomy for treatment of restenosis within coronary stents: Clinical, angiographic and histologic results

OBJECTIVES

The safety and long-term results of directional coronary atherectomy in stented coronary arteries were determined. In addition, tissue studies were performed to characterize the development of restenosis.

METHODS

Directional coronary atherectomy was performed in restenosed stents in nine patients (10 procedures) 82 to 1,179 days after stenting. The tissue was assessed for histologic features of restenosis, smooth muscle cell phenotype, markers of cell proliferation and cell density. A control (no stenting) group consisted of 13 patients treated with directional coronary atherectomy for restenosis 14 to 597 days after coronary angioplasty, directional coronary atherectomy or laser intervention.

RESULTS

Directional coronary atherectomy procedures within the stent were technically successful with results similar to those of the initial stenting procedure (2.31 +/- 0.38 vs. 2.44 +/- 0.35 mm). Of five patients with angiographic follow-up, three had restenosis requiring reintervention (surgery in two and repeat atherectomy followed by laser angioplasty in one). Intimal hyperplasia was identified in 80% of specimens after stenting and in 77% after coronary angioplasty or atherectomy. In three patients with stenting, 70% to 76% of the intimal cells showed morphologic features of a contractile phenotype by electron microscopy 47 to 185 days after coronary intervention. Evidence of ongoing proliferation (proliferating cell nuclear antigen antibody studies) was absent in all specimens studied. Although wide individual variability was present in the maximal cell density of the intimal hyperplasia, there was a trend toward a reduction in cell density over time.

CONCLUSIONS

Although atherectomy is feasible for the treatment of restenosis in stented coronary arteries and initial results are excellent, recurrence of restenosis is common. Intimal hyperplasia is a nonspecific response to injury regardless of the device used and accounts for about 80% of cases of restenosis. Smooth muscle cell proliferation and phenotypic modulation toward a contractile phenotype are early events and largely completed by the time of clinical presentation of restenosis. Restenotic lesions may be predominantly cellular, matrix or a combination at a particular time after a coronary procedure.