Ticagrelor or Clopidogrel Monotherapy vs Dual Antiplatelet Therapy After Percutaneous Coronary Intervention: A Systematic Review and Patient-Level Meta-Analysis

Importance

Among patients undergoing percutaneous coronary intervention (PCI), it remains unclear whether the treatment efficacy of P2Y12 inhibitor monotherapy after a short course of dual antiplatelet therapy (DAPT) depends on the type of P2Y12 inhibitor.

Objective

To assess the risks and benefits of ticagrelor monotherapy or clopidogrel monotherapy compared with standard DAPT after PCI.

Data Sources

MEDLINE, Embase, TCTMD, and the European Society of Cardiology website were searched from inception to September 10, 2023, without language restriction.

Study Selection

Included studies were randomized clinical trials comparing P2Y12 inhibitor monotherapy with DAPT on adjudicated end points in patients without indication to oral anticoagulation undergoing PCI.

Data Extraction and Synthesis

Patient-level data provided by each trial were synthesized into a pooled dataset and analyzed using a 1-step mixed-effects model. The study is reported following the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data.

Main Outcomes and Measures

The primary objective was to determine noninferiority of ticagrelor or clopidogrel monotherapy vs DAPT on the composite of death, myocardial infarction (MI), or stroke in the per-protocol analysis with a 1.15 margin for the hazard ratio (HR). Key secondary end points were major bleeding and net adverse clinical events (NACE), including the primary end point and major bleeding.

Results

Analyses included 6 randomized trials including 25 960 patients undergoing PCI, of whom 24 394 patients (12 403 patients receiving DAPT; 8292 patients receiving ticagrelor monotherapy; 3654 patients receiving clopidogrel monotherapy; 45 patients receiving prasugrel monotherapy) were retained in the per-protocol analysis. Trials of ticagrelor monotherapy were conducted in Asia, Europe, and North America; trials of clopidogrel monotherapy were all conducted in Asia. Ticagrelor was noninferior to DAPT for the primary end point (HR, 0.89; 95% CI, 0.74-1.06; P for noninferiority = .004), but clopidogrel was not noninferior (HR, 1.37; 95% CI, 1.01-1.87; P for noninferiority > .99), with this finding driven by noncardiovascular death. The risk of major bleeding was lower with both ticagrelor (HR, 0.47; 95% CI, 0.36-0.62; P < .001) and clopidogrel monotherapy (HR, 0.49; 95% CI, 0.30-0.81; P = .006; P for interaction = 0.88). NACE were lower with ticagrelor (HR, 0.74; 95% CI, 0.64-0.86, P < .001) but not with clopidogrel monotherapy (HR, 1.00; 95% CI, 0.78-1.28; P = .99; P for interaction = .04).

Conclusions and Relevance

This systematic review and meta-analysis found that ticagrelor monotherapy was noninferior to DAPT for all-cause death, MI, or stroke and superior for major bleeding and NACE. Clopidogrel monotherapy was similarly associated with reduced bleeding but was not noninferior to DAPT for all-cause death, MI, or stroke, largely because of risk observed in 1 trial that exclusively included East Asian patients and a hazard that was driven by an excess of noncardiovascular death.

P2Y12 Inhibitor Monotherapy or Dual Antiplatelet Therapy After Complex Percutaneous Coronary Interventions

BACKGROUND

It remains unclear whether P2Y₁₂ inhibitor monotherapy preserves ischemic protection while limiting bleeding risk compared with dual antiplatelet therapy (DAPT) after complex percutaneous coronary intervention (PCI).

OBJECTIVES

We sought to assess the effects of P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT vs standard DAPT in relation to PCI complexity.

METHODS

We pooled patient-level data from randomized controlled trials comparing P2Y₁₂ inhibitor monotherapy and standard DAPT on centrally adjudicated outcomes after coronary revascularization. Complex PCI was defined as any of 6 criteria: 3 vessels treated, ≥3 stents implanted, ≥3 lesions treated, bifurcation with 2 stents implanted, total stent length >60 mm, or chronic total occlusion. The primary efficacy endpoint was all-cause mortality, myocardial infarction, and stroke. The key safety endpoint was Bleeding Academic Research Consortium (BARC) 3 or 5 bleeding.

RESULTS

Of 22,941 patients undergoing PCI from 5 trials, 4,685 (20.4%) with complex PCI had higher rates of ischemic events. The primary efficacy endpoint was similar between P2Y₁₂ inhibitor monotherapy and DAPT among patients with complex PCI (HR: 0.87; 95% CI: 0.64-1.19) and noncomplex PCI (HR: 0.91; 95% CI: 0.76-1.09; P_interaction = 0.770). The treatment effect was consistent across all the components of the complex PCI definition. Compared with DAPT, P2Y₁₂ inhibitor monotherapy consistently reduced BARC 3 or 5 bleeding in complex PCI (HR: 0.51; 95% CI: 0.31-0.84) and noncomplex PCI patients (HR: 0.49; 95% CI: 0.37-0.64; P_interaction = 0.920).

CONCLUSIONS

P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT was associated with similar rates of fatal and ischemic events and lower risk of major bleeding compared with standard DAPT, irrespective of PCI complexity. (PROSPERO [P2Y12 Inhibitor Monotherapy Versus Standard Dual Antiplatelet Therapy After Coronary Revascularization: Individual Patient Data Meta-Analysis of Randomized Trials]; CRD42020176853).

Ticagrelor Monotherapy Versus Dual-Antiplatelet Therapy After PCI: An Individual Patient-Level Meta-Analysis

OBJECTIVES

The aim of this study was to compare ticagrelor monotherapy with dual-antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug-eluting stents.

BACKGROUND

The role of abbreviated DAPT followed by an oral P2Y₁₂ inhibitor after PCI remains uncertain.

METHODS

Two randomized trials, including 14,628 patients undergoing PCI, comparing ticagrelor monotherapy with standard DAPT on centrally adjudicated endpoints were identified, and individual patient data were analyzed using 1-step fixed-effect models. The protocol was registered in PROSPERO (CRD42019143120). The primary outcomes were the composite of Bleeding Academic Research Consortium type 3 or 5 bleeding tested for superiority and, if met, the composite of all-cause death, myocardial infarction, or stroke at 1 year, tested for noninferiority against a margin of 1.25 on a hazard ratio (HR) scale.

RESULTS

Bleeding Academic Research Consortium type 3 or 5 bleeding occurred in fewer patients with ticagrelor than DAPT (0.9% vs. 1.7%, respectively; HR: 0.56; 95% confidence interval [CI]: 0.41 to 0.75; p < 0.001). The composite of all-cause death, myocardial infarction, or stroke occurred in 231 patients (3.2%) with ticagrelor and in 254 patients (3.5%) with DAPT (HR: 0.92; 95% CI: 0.76 to 1.10; p < 0.001 for noninferiority). Ticagrelor was associated with lower risk for all-cause (HR: 0.71; 95% CI: 0.52 to 0.96; p = 0.027) and cardiovascular (HR: 0.68; 95% CI: 0.47 to 0.99; p = 0.044) mortality. Rates of myocardial infarction (2.01% vs. 2.05%; p = 0.88), stent thrombosis (0.29% vs. 0.38%; p = 0.32), and stroke (0.47% vs. 0.36%; p = 0.30) were similar.

CONCLUSIONS

Ticagrelor monotherapy was associated with a lower risk for major bleeding compared with standard DAPT, without a concomitant increase in ischemic events.

P2Y12 inhibitor monotherapy or dual antiplatelet therapy after coronary revascularisation: individual patient level meta-analysis of randomised controlled trials

OBJECTIVE

To assess the risks and benefits of P2Y₁₂ inhibitor monotherapy compared with dual antiplatelet therapy (DAPT) and whether these associations are modified by patients' characteristics.

DESIGN

Individual patient level meta-analysis of randomised controlled trials.

DATA SOURCES

Searches were conducted in Ovid Medline, Embase, and three websites (www.tctmd.com, www.escardio.org, www.acc.org/cardiosourceplus) from inception to 16 July 2020. The primary authors provided individual participant data.

ELIGIBILITY CRITERIA

Randomised controlled trials comparing effects of oral P2Y₁₂ monotherapy and DAPT on centrally adjudicated endpoints after coronary revascularisation in patients without an indication for oral anticoagulation.

MAIN OUTCOME MEASURES

The primary outcome was a composite of all cause death, myocardial infarction, and stroke, tested for non-inferiority against a margin of 1.15 for the hazard ratio. The key safety endpoint was Bleeding Academic Research Consortium (BARC) type 3 or type 5 bleeding.

RESULTS

The meta-analysis included data from six trials, including 24 096 patients. The primary outcome occurred in 283 (2.95%) patients with P2Y₁₂ inhibitor monotherapy and 315 (3.27%) with DAPT in the per protocol population (hazard ratio 0.93, 95% confidence interval 0.79 to 1.09; P=0.005 for non-inferiority; P=0.38 for superiority; τ²=0.00) and in 303 (2.94%) with P2Y₁₂ inhibitor monotherapy and 338 (3.36%) with DAPT in the intention to treat population (0.90, 0.77 to 1.05; P=0.18 for superiority; τ²=0.00). The treatment effect was consistent across all subgroups, except for sex (P for interaction=0.02), suggesting that P2Y₁₂ inhibitor monotherapy lowers the risk of the primary ischaemic endpoint in women (hazard ratio 0.64, 0.46 to 0.89) but not in men (1.00, 0.83 to 1.19). The risk of bleeding was lower with P2Y₁₂ inhibitor monotherapy than with DAPT (97 (0.89%) v 197 (1.83%); hazard ratio 0.49, 0.39 to 0.63; P<0.001; τ²=0.03), which was consistent across subgroups, except for type of P2Y₁₂ inhibitor (P for interaction=0.02), suggesting greater benefit when a newer P2Y₁₂ inhibitor rather than clopidogrel was part of the DAPT regimen.

CONCLUSIONS

P2Y₁₂ inhibitor monotherapy was associated with a similar risk of death, myocardial infarction, or stroke, with evidence that this association may be modified by sex, and a lower bleeding risk compared with DAPT.

REGISTRATION

PROSPERO CRD42020176853.

Comparison of primary angioplasty and pre-hospital fibrinolysis in acute myocardial infarction (CAPTIM) trial: a 5-year follow-up

AIMS

The CAPTIM (Comparison of primary Angioplasty and Pre-hospital fibrinolysis In acute Myocardial infarction) study found no evidence that a strategy of primary angioplasty was superior in terms of 30-day outcomes to a strategy of pre-hospital fibrinolysis with transfer to an interventional facility in patients managed early at the acute phase of an acute myocardial infarction. The present analysis was designed to compare both strategies at 5 years.

METHODS AND RESULTS

The CAPTIM study included 840 patients managed in a pre-hospital setting within 6 h of an acute ST-segment elevation myocardial infarction. Patients were randomized to either a primary angioplasty (n = 421) or a pre-hospital fibrinolysis (rt-PA) with immediate transfer to a centre with interventional facilities (n = 419). Long-term follow-up was obtained in blinded fashion from 795 patients (94.6%). Using an intent-to-treat analysis, all-cause mortality at 5 years was 9.7% in the pre-hospital fibrinolysis group when compared with 12.6% in the primary angioplasty group [HR 0.75 (95% CI, 0.50-1.14); P = 0.18]. For patients included within 2 h, 5 year mortality was 5.8% in the pre-hospital fibrinolysis group when compared with 11.1% in the primary angioplasty group [HR 0.50 (95% CI, 0.25-0.97); P = 0.04], whereas it was, respectively, 14.5 and 14.4% in patients included after 2 h [HR 1.02, (95% CI 0.59-1.75), P = 0.92].

CONCLUSION

The 5-year follow-up is consistent with the 30-day outcomes of the trial, showing similar mortality for primary percutaneous coronary intervention and a policy of pre-hospital lysis followed by transfer to an interventional center. In addition, for patients treated within 2 h of symptom onset, 5-year mortality was lower with pre-hospital lysis.

One year clinical follow up of paclitaxel eluting stents for acute myocardial infarction compared with sirolimus eluting stents

OBJECTIVE

To compare clinical outcome of paclitaxel eluting stents (PES) versus sirolimus eluting stents (SES) for the treatment of acute ST elevation myocardial infarction.

DESIGN AND PATIENTS

The first 136 consecutive patients treated exclusively with PES in the setting of primary percutaneous coronary intervention for acute myocardial infarction in this single centre registry were prospectively clinically assessed at 30 days and one year. They were compared with 186 consecutive patients treated exclusively with SES in the preceding period.

SETTING

Academic tertiary referral centre.

RESULTS

At 30 days, the rate of all cause mortality and reinfarction was similar between groups (6.5% v 6.6% for SES and PES, respectively, p = 1.0). A significant difference in target vessel revascularisation (TVR) was seen in favour of SES (1.1% v 5.1% for PES, p = 0.04). This was driven by stent thrombosis (n = 4), especially in the bifurcation stenting (n = 2). At one year, no significant differences were seen between groups, with no late thrombosis and 1.5% in-stent restenosis (needing TVR) in PES versus no reinterventions in SES (p = 0.2). One year survival free of major adverse cardiac events (MACE) was 90.2% for SES and 85% for PES (p = 0.16).

CONCLUSIONS

No significant differences were seen in MACE-free survival at one year between SES and PES for the treatment of acute myocardial infarction with very low rates of reintervention for restenosis. Bifurcation stenting in acute myocardial infarction should, if possible, be avoided because of the increased risk of stent thrombosis.

Visualization of elusive structures using intracardiac echocardiography: insights from electrophysiology

Electrophysiological mapping and ablation techniques are increasingly used to diagnose and treat many types of supraventricular and ventricular tachycardias. These procedures require an intimate knowledge of intracardiac anatomy and their use has led to a renewed interest in visualization of specific structures. This has required collaborative efforts from imaging as well as electrophysiology experts. Classical imaging techniques may be unable to visualize structures involved in arrhythmia mechanisms and therapy. Novel methods, such as intracardiac echocardiography and three-dimensional echocardiography, have been refined and these technological improvements have opened new perspectives for more effective and accurate imaging during electrophysiology procedures. Concurrently, visualization of these structures noticeably improved our ability to identify intracardiac structures. The aim of this review is to provide electrophysiologists with an overview of recent insights into the structure of the heart obtained with intracardiac echocardiography and to indicate to the echo-specialist which structures are potentially important for the electrophysiologist.

Anterior chordal transection impairs not only regional left ventricular function but also regional right ventricular function in mitral regurgitation

BACKGROUND

Preservation of annuloventricular continuity through the chordae tendinae aims to maintain left ventricular (LV) function and thus improve postoperative prognosis. This study was designed to prospectively investigate the effect of anterior chordal transection on global and regional LV and right ventricular (RV) function in mitral regurgitation (MR).

METHODS AND RESULTS

Sixty-five patients with severe MR underwent radionuclide angiography before and after either mitral valve (MV) repair (42 patients) or replacement with anterior chordal transection (23 patients). LV and RV ejection fractions (EF) were determined at rest. Both ventricles were divided into 9 regions to analyze regional EF and the effect of anteromedial translation related to surgery. After surgery there was a significant decrease in LVEF (P=0.038) and an increase in RVEF (P=0.036). However, LVEF did not change after MV repair (63.8+/-9.9% to 62.6+/-10.3%), whereas RVEF improved (40.7+/-10.1% to 44.5+/-8.1%, P=0.027). In contrast, LVEF decreased after MV replacement (61.7+/-10.1% to 57.2+/-9.9%, P=0.03), and RVEF was unchanged (40.9+/-10.9% to 41.3+/-9.1%). LVEF 4 and 5, in the area of anterior papillary muscle insertion, were impaired after MV replacement compared with MV repair (region 4, 77.6+/-16.7% versus 87.7+/-10.8%, P=0.005, and region 5, 73.9+/-19.3% versus 89.9+/-13.1%, P<0.001). Moreover, anterior chordal transection led to a significant impairment in the apicoseptal region of the RV (RVEF 4, 50.3+/-15.6% versus 59.3+/-13.8%, P=0.02).

CONCLUSIONS

Anterior chordal transection during MV replacement for MR impairs not only regional LV function but also regional RV function.

Echocardiographic features of Candidaspecies endocarditis: 12 cases and a review of published reports

OBJECTIVE

To describe the specific echocardiographic features of Candidaspecies endocarditis.

DESIGN

Retrospective review of the case records of patients with confirmed candida endocarditis.

SETTING

Cases referred to three French university centres over an eight year period were studied.

DESIGN

12 patients with confirmedCandida species endocarditis infection were identified. The transthoracic (n = 12) and transoesophageal (n = 12) echocardiographic appearances were compared with the surgical findings (n = 10).

RESULTS

Large dense heterogeneous vegetations were found in 11/12 cases. A hyperechogenic heterogeneous myocardial texture, observed in seven of the 12 patients, was associated with extensive myocardial damage at surgery. While it was possible to diagnose candidal cardiac infection in all patients by transthoracic echocardiography, transoesophageal echocardiography was useful for optimal assessment of the valvar and paravalvar structures.

CONCLUSIONS

In the setting of endocarditis, the detection of myocardial involvement, which is characterised by a heterogeneous myocardial texture, is an argument in favour of Candida species endocarditis and may warrant early surgical intervention.

Echocardiographic features of Candida species endocarditis: 12 cases and a review of published reports

OBJECTIVE

To describe the specific echocardiographic features of Candida species endocarditis.

DESIGN

Retrospective review of the case records of patients with confirmed candida endocarditis.

SETTING

Cases referred to three French university centres over an eight year period were studied.

DESIGN

12 patients with confirmed Candida species endocarditis infection were identified. The transthoracic (n = 12) and transoesophageal (n = 12) echocardiographic appearances were compared with the surgical findings (n = 10).

RESULTS

Large dense heterogeneous vegetations were found in 11/12 cases. A hyperechogenic heterogeneous myocardial texture, observed in seven of the 12 patients, was associated with extensive myocardial damage at surgery. While it was possible to diagnose candidal cardiac infection in all patients by transthoracic echocardiography, transoesophageal echocardiography was useful for optimal assessment of the valvar and paravalvar structures.

CONCLUSIONS

In the setting of endocarditis, the detection of myocardial involvement, which is characterised by a heterogeneous myocardial texture, is an argument in favour of Candida species endocarditis and may warrant early surgical intervention.

Prospective evaluation of magnetic resonance imaging after endovascular treatment of infrarenal aortic aneurysms

OBJECTIVES

to evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) in the detection of type II endoleaks during follow-up after endovascular treatment of intra-renal aortic aneurysms.

DESIGN

prospective study.

MATERIAL AND METHODS

between March 1996 and November 1999, 31 patients with infra-renal aortic aneurysms who underwent stentgraft implantation were followed with helical CT and MRI, including magnetic resonance angiography (MRA), at 1 and 6 months after the procedure. Arteriography was performed between 6 and 12 months after intervention. The parameters studied included the change in the maximum anteroposterior and transverse diameters, the nature of the signal on T1 and T2 weighted sequences (homogeneous vs heterogeneous), the presence or absence of Gadolinium uptake on MRI or of contrast uptake on helical CT (early and late phases) in the sac of the aneurysm. On MRA, stentgraft patency and endoleak detection were studied.

RESULTS

arteriography demonstrated an endoleak in 19 patients (18 type II, and 1 type I endoleak). MRI at 6 months detected 18/19 endoleaks on T1 weighted sequences after injection of Gadoliniumj; there were 2 false positives. MRA sequences confirmed stentgraft patency in all patients, but did not diagnose type II endoleaks. Helical CT (late phase) at 6 months detected 10/19 endoleaks; there was 1 false positive. The sensitivity of MRI after injection of Gadolinium and of helical CT for the detection of type II endoleaks were 94% and 50% (p=0.003) respectively. The mean maximal anteroposterior and transverse diameters were similar on MRI and on helical CT at 1 month and at 6 months.

CONCLUSION

MRI after injection of Gadolinium is more sensitive than helical CT in the detection of type II endoleaks after stentgraft implantation. Its more widespread use may permit earlier intervention in such patients.

Rare variations in renal anatomy and blood supply: CT appearances and embryological background. A pictorial essay

Helical CT angiography is increasingly used for the evaluation of the kidneys and the renal vessels. Knowledge of the potential variants in renal and renal vascular anatomy and of their appearances on helical CT are thus indispensable for radiologists who perform and interpret such examinations. We report six cases of anatomic variants that we encountered in our tertiary referral centre over the past 5 years, during which time we have performed 4850 helical CT angiograms, including 1432 renal artery examinations. These represent rarer anomalies in renal vascularization, most of which were associated with renal malformations (horseshoe kidney with or without cortical torsion, renal malrotation, single kidney, and thoracic origin of a renal artery). We present the helical CT findings and discuss the possible embryological mechanisms and the practical implications of these abnormalities for the radiologist.

Patency of percutaneous transluminal coronary angioplasty sites at 6-month angiographic follow-up: A key determinant of survival in diabetics after coronary balloon angioplasty

BACKGROUND

Several reports have demonstrated a high mortality rate in diabetic patients treated by standard coronary balloon angioplasty. No clear explanation has been provided for this finding.

METHODS AND RESULTS

Consecutive diabetic patients successfully treated by standard coronary balloon angioplasty (n=604) were enrolled in a follow-up program including repeated angiography at 6 months and long-term clinical follow-up. Clinical follow-up was available in 603 patients (99.8%). Twelve patients died, 2 underwent bypass surgery before scheduled repeated angiography, and 76 declined angiography. Determinants of long-term mortality were analyzed in the 513 patients with angiography at 6 months and long-term clinical follow-up (mean follow-up, 6.5+/-2.4 years). On the basis of the results of repeated angiography, 3 groups of patients were defined: group 1, 162 patients without restenosis (32%); group 2, 257 patients with nonocclusive restenosis (50%); and group 3, 94 patients with coronary occlusion (18%). Overall actuarial 10-year mortality rate was 36%. Actuarial 10-year mortality was 24% in group 1, 35% in group 2, and 59% in group 3 (P:<0.0001). Multivariate analysis demonstrated that coronary occlusion was a strong and independent correlate of long-term total mortality (hazard ratio, 2.16; 95% CI, 1.43 to 3.26; P:=0.0003) and cardiac mortality (hazard ratio, 2.38; 95% CI, 1.48 to 3.85; P:=0.0004).

CONCLUSIONS

This study demonstrates that restenosis, especially in its occlusive form, is a major determinant of long-term mortality in diabetic patients after coronary balloon angioplasty.

Doppler flow wire evaluation of renal blood flow reserve in hypertensive patients with normal renal arteries

PURPOSE

To study the vasomotor responses of the renal microcirculation in patients with essential hypertension.

METHODS

We studied the reactivity of the renal microcirculation to papaverine, with intraarterial Doppler and quantitative arteriography, in 34 renal arteries of 19 hypertensive patients without significant renal artery stenosis. Isosorbide dinitrate was given to maximally dilate proximal renal arteries. APV (average peak blood flow velocity) was used as an index of renal blood flow.

RESULTS

Kidneys could be divided into two distinct subgroups based on their response to papaverine. An increase in APV of up to 55% occurred in 21 kidneys, an increase > 55% in 13 kidneys. Within each group the values were normally distributed. Both baseline APV and the effect of papaverine on mean velocity differed significantly between groups.

CONCLUSION

There seems to be a subgroup of patients with essential hypertension that has an impaired reactivity to papaverine, consistent with a functional impairment of the renal microcirculation. Further studies are required to determine whether this abnormality contributes to or results from elevated blood pressure.

Endovascular treatment for dissection of the descending aorta

Surgery for acute ischaemia complicating dissection of the descending aorta is associated with high mortality. We used an endovascular fenestration approach (scissor technique) to treat seven of 12 patients with ischaemic complications of descending aortic dissection; the remaining five patients were treated by stent implantation. Four of the 12 patients died (two in the fenestration group and two in the stenting group) in the days after the procedure. The remaining eight were symptom-free a mean of 9.4 (SD 8) months later. We suggest that the fenestration approach is a promising addition to endovascular treatment for patients with ischaemic complications of descending aortic dissection.

Mid-term comparative follow-up after aortic valve replacement with Carpentier-Edwards and Pericarbon pericardial prostheses

BACKGROUND

The first generation of pericardial valves had a high rate of premature deterioration. The aim of this study was to compare the outcome after aortic valve replacement with second generation pericardial prostheses (Pericarbon and Carpentier-Edwards).

METHODS AND RESULTS

Between 1987 and 1994, 162 patients underwent aortic valve replacement with either a Pericarbon (n=81, 69+/-11 years) or a Carpentier-Edwards (n=81, 70+/-11 years) pericardial prosthesis. Mean follow-up was 4.4+/-2.7 years for Pericarbon and 4.8+/-2.4 years for Carpentier-Edwards valves (P=0. 27), giving a total follow-up of 745 patient-years. Thirty-day mortality and 5-year actuarial survival were, respectively, 6.2% and 63.2+/-5.7% in the Pericarbon group and 6.2% and 63.5+/-5.6% in the Carpentier-Edwards group. At 8 years, freedom from (and linearized rates per patient-year) thromboembolism, structural failure, and all valve-related events were, respectively, 91.8+/-3.6% (1.4%), 76. 9+/-8.7% (2.5%), and 58.4+/-9.3% (5.6%) in the Pericarbon group and 94.4+/-2.7% (1%), 100% (0%, P<0.01), and 88.8+/-3.7% (2%, P<0.05) in the Carpentier-Edwards group. There were 9 (11.1%) Pericarbon structural failures related predominantly to severe calcification and stenosis. The actual reoperation rate was 7.4% (1.6% per patient-year) in the Pericarbon group for fibrocalcific degeneration (n=3), periprosthetic leak (n=1), endocarditis (n=1), and aortic dissection (n=1). There was neither structural valve failure nor valve reoperation in the Carpentier-Edwards group. Echocardiographic review of 70 patients from 85 survivors (82.3%) found 4 additional Pericarbon valves with signs of early structural failure but no Carpentier-Edwards valve with such changes.

CONCLUSIONS

Eight years after aortic valve replacement, Pericarbon pericardial prostheses compared unfavorably with Carpentier-Edwards pericardial prostheses, with a high incidence of structural valve failure and reoperation.

Restenosis, late vessel occlusion and left ventricular function six months after balloon angioplasty in diabetic patients

OBJECTIVES

We studied angiographic outcome and its predictors after traditional coronary balloon angioplasty in diabetics. We further examined whether changes in ejection fraction were influenced by the status of the dilated site(s) at follow-up.

BACKGROUND

Recent studies have suggested that diabetics have a particularly poor outcome after balloon angioplasty. The reasons for this observation are not known.

METHODS

We investigated procedural and six-month angiographic outcome, analyzed by quantitative coronary angiography, and left ventricular function in 485 consecutive diabetics (627 lesions) treated by balloon angioplasty without stent implantation.

RESULTS

The procedure was successful in 455 (94%) patients; angiographic follow-up was available in 377 patients (83%). At follow-up, the rates of restenosis and total occlusion were 62% and 13%, respectively. Five independent predictors of restenosis were identified: the presence of organ damage, a saphenous vein graft (SVG) angioplasty, a bifurcation lesion, a Thrombolysis in Myocardial Infarction (TIMI) flow <3 preprocedure and the degree of residual stenosis. Four independent predictors of vessel occlusion were identified: treatment with insulin, a SVG angioplasty, a TIMI flow <3 preprocedure and the degree of residual stenosis after angioplasty. Late vessel occlusion at angioplasty site(s) was observed in 15% of patients, ranging from 11% for a one-site procedure to 37% for a three-site procedure. This complication was associated with a decrease in ejection fraction at follow-up (-6.2 +/- 9.9%, p = 0.0001), whereas no significant change was observed in patients without occlusion.

CONCLUSIONS

This study shows that late vessel occlusion is a frequent mode of restenosis in diabetic patients and is associated with a significant decrease in ejection fraction. This could partly explain the poor long-term clinical outcome reported in such patients after traditional balloon angioplasty.

Randomized multicenter comparison of conventional anticoagulation versus antiplatelet therapy in unplanned and elective coronary stenting. The full anticoagulation versus aspirin and ticlopidine (fantastic) study

BACKGROUND

Dual therapy with ticlopidine and aspirin has been shown to be as effective as or more effective than conventional anticoagulation in patients with an optimal result after implantation of intracoronary metallic stents. However, the safety and efficacy of antiplatelet therapy alone in an unselected population has not been evaluated.

METHODS

Patients were randomized to conventional anticoagulation or to treatment with antiplatelet therapy alone. Indications for stenting were classified as elective (decided before the procedure) or unplanned (to salvage failed angioplasty or to optimize the results of balloon angioplasty). After stenting, patients received aspirin and either ticlopidine or conventional anticoagulation (heparin or oral anticoagulant). The primary end point was the occurrence of bleeding or peripheral vascular complications; secondary end points were cardiac events (death, infarction, or stent occlusion) and duration of hospitalization.

RESULTS

In 13 centers, 236 patients were randomized to anticoagulation and 249 to antiplatelet therapy. Stenting was elective in 58% of patients and unplanned in 42%. Stent implantation was successfully achieved in 99% of patients. A primary end point occurred in 33 patients (13.5%) in the antiplatelet group and 48 patients (21%) in the anticoagulation group (odds ratio=0.6 [95% CI 0.36 to 0.98], P=0.03). Major cardiac-related events in electively stented patients were less common (odds ratio=0.23 [95% CI 0.05 to 0.91], P=0.01) in the antiplatelet group (3 of 123, 2.4%) than the anticoagulation group (11 of 111, 9.9%). Hospital stay was significantly shorter in the antiplatelet group (4.3+/-3.6 versus 6. 4+/-3.7 days, P=0.0001).

CONCLUSIONS

Antiplatelet therapy after coronary stenting significantly reduced rates of bleeding and subacute stent occlusion compared with conventional anticoagulation.

Predictors of restenosis after coronary stent implantation

OBJECTIVES

We sought to determine predictors of restenosis after coronary stenting (CS) in a consecutive series of patients.

BACKGROUND

Although stenting in highly selected patient groups reduces restenosis, the results of stenting in a heterogeneous patient group and the effects of clinical and procedural factors on stent restenosis are currently unclear.

METHODS

We analyzed the 6-month angiographic outcome of 500 lesions in 463 consecutive patients undergoing successful CS. Clinical, qualitative and quantitative angiographic variables were correlated with restenosis assessed as both a binary and a continuous variable.

RESULTS

Restenosis, defined as the presence of >50% diameter stenosis in the dilated segment, was present in 105 (26%) of the 405 lesions with angiographic follow-up. The mean late lumen loss during the follow-up period was 0.79+/-0.64 mm. Implantation of multiple stents (p < 0.0001) and a high acute gain (p < 0.0002) were independently associated with a higher late lumen loss. In contrast, the use of high inflation pressure (p < 0.02) and Palmaz-Schatz stents (p < 0.005) was independently associated with a lower late lumen loss. When restenosis was defined as a qualitative variable, implantation of multiple stents (p < 0.001), stenosis length (p < 0.01), small reference diameter (p < 0.02) and stent type other than Palmaz-Schatz (p < 0.01) were independent predictors of restenosis. None of the clinical variables tested was associated with restenosis.

CONCLUSIONS

Coronary stenting in an unselected patient group is associated with an acceptable restenosis rate. Although some risk factors were identified, the risk of restenosis was not related to most of the variables tested. This suggests that the superiority of CS over balloon angioplasty, in terms of restenosis, might also apply to subgroups of patients that were not included in the recent randomized studies.

Coronary angioscopic findings in the infarct-related vessel within 1 month of acute myocardial infarction: natural history and the effect of thrombolysis

BACKGROUND

Limited angioscopic information is available on the natural history of infarct-related plaque after myocardial infarction (MI), in particular the effect of thrombolysis.

METHODS AND RESULTS

We studied with angioscopy the morphological characteristics of the infarct-related lesion in 56 patients between 24 hours and 4 weeks after MI. Forty of these patients were initially treated with a thrombolytic agent. Most lesions were complex (complex + ulcerated shape = 54%). The predominant color of the plaque was yellow in 79% of cases; only 6% were uniformly white. Angioscopically visible thrombus was found in 77% of cases. Despite angioscopic evidence of instability, only 7% of the patients had post-MI angina. During the 1-month time window since the occurrence of MI, there was no significant difference in the angioscopic appearance of the plaque except for a slight increase in uniformly white plaques (P=.07). The use of a thrombolytic agent at the onset of MI was associated with a reduction in thrombus size and less protruding thrombi (P=.02) but not with a decreased frequency of plaque containing thrombi. Furthermore, a trend for more frequently ulcerated plaques (45% versus 16%, P=.06) was associated with the use of a thrombolytic agent.

CONCLUSIONS

These results suggest that healing of the infarct-related lesion requires more than 1 month and that an "unstable" yellow plaque with adherent thrombus is common during that period. This finding may partly explain the unique behavior of recent infarct-related lesions, which are more prone to occlude than other lesions.

Dual determination of angiotensin-converting enzyme and angiotensin-II type 1 receptor genotypes as predictors of restenosis after coronary angioplasty

This study sought to assess the potential influence of the angiotensin-converting enzyme (ACE) and angiotensin II type 1 (AT1) receptor gene polymorphisms on restenosis after coronary balloon angioplasty. The authors conclude that screening for genetic suspectibility to restenosis based on genotyping of ACE and AT1 receptor polymorphisms before conventional balloon angioplasty is not clinically useful.

Effect of nadroparin, a low-molecular-weight heparin, on clinical and angiographic restenosis after coronary balloon angioplasty: the FACT study. Fraxiparine Angioplastie Coronaire Transluminale

BACKGROUND

Experimental studies suggest that the antiproliferative effect of heparin after arterial injury is maximized by pretreatment. No previous studies of restenosis have used a pretreatment strategy. We designed this study to determine whether treatment with nadroparin, a low-molecular-weight heparin, started 3 days before the procedure and continued for 3 months, affected angiographic restenosis or clinical outcome after coronary angioplasty.

METHODS AND RESULTS

In a prospective multicenter, double-blind, randomized trial, elective coronary angioplasty was performed on 354 patients who were treated with daily subcutaneous nadroparin (0.6 mL of 10,250 anti-Xa IU/mL) or placebo injections started 3 days before angioplasty and continued for 3 months. Angiography was performed just before and immediately after angioplasty and at follow-up. The primary study end point was angiographic restenosis, assessed by quantitative coronary angiography 3 months after balloon angioplasty. Clinical follow-up was continued up to 6 months. Clinical and procedural variables and the occurrence of periprocedural complications did not differ between groups. At angiographic follow-up, the mean minimal lumen diameter and the mean residual stenosis in the nadroparin group (1.37+/-0.66 mm, 51.9+/-21.0%) did not differ from the corresponding values in the control group (1.48+/-0.59 mm, 48.8+/-18.9%). Combined major cardiac-related clinical events (death, myocardial infarction, target lesion revascularization) did not differ between groups (30.3% versus 29.6%).

CONCLUSIONS

Pretreatment with the low-molecular-weight heparin nadroparin continued for 3 months after balloon angioplasty had no beneficial effect on angiographic restenosis or on adverse clinical outcomes.

Effects of stenting of recent or chronic coronary occlusions on late vessel patency and left ventricular function

Due to high rates of late vessel reocclusion, balloon angioplasty of recent or chronic coronary occlusions is not associated with a sustained improvement in left ventricular function. Recent studies have suggested that stent implantation at coronary occlusions significantly reduces late vessel occlusion. We thus designed a study to analyze the effect of stent implantation at coronary occlusions on late vessel potency and left ventricular function. Twenty-four consecutive patients with recent or chronic coronary occlusions had successful stent implantation and were enrolled in a 6-month angiographic follow-up program. Contrast left ventricular cineangiography, at baseline and 6-month follow-up, as well as preprocedural, postprocedural, and follow-up angiograms analyzed with quantitative angiography were available in 22 of the patients (92%). At follow-up, no vessel reocclusion was observed and 32% of the patients, as analyzed by the >50% diameter stenosis criterion, had restenosis. There was a significant improvement in global left ventricular function with a decrease in both left ventricular end-diastolic volume index (LVEDVI, p <0.01) and left ventricular end-systolic volume index (LVESVI, p <0.0001) and an increase in left ventricular ejection fraction (LVEF, p <0.0001). Similarly, regional wall motion in the territory of the recanalized artery was also significantly improved (p <0.05). These effects were associated with a reduction in left ventricular filling pressure (p <0.0001). Stent implantation following balloon angioplasty of recent or chronic coronary occlusion is associated with a low rate of late vessel reocclusion, a reduction in cardiac volume, and an increase in ejection fraction. Such effects on left ventricular volumes could have a significant impact on patient survival.

Effects of coronary angioplasty on monocyte tissue factor response in patients with stable or unstable angina

Balloon coronary angioplasty is a revascularization procedure which increases the luminal diameter at a site of arterial stenosis, leading to mechanical disruption of the atherosclerotic plaque and to stretching of the vascular wall (1). This procedure can be complicated by thrombosis or restenosis, which occur in 5% and 30% of the cases respectively (2). These complications probably result from exposure of blood to components of atherosclerotic plaque, subendothelium and components of vascular wall, leading to activation of coagulation (thrombin generation) and platelets (3,4). Recent data point to simultaneous increase of leukocyte adhesive receptors, indicating an additional process of leukocyte activation, which could play a key role in the vascular healing process after angioplasty (5). These elements could also play a role in the thrombotic and stenotic complications.

[Recanalization of complete coronary occlusions followed by STENT implantation. An angiographic study after 6 months]

The restenosis and reocclusion rate after coronary recanalization by conventional angioplasty are high. The role of stent implantation in this context is unknown. The authors assessed a group of 49 patients who underwent implantation of one or more stent after a recanalization procedure by angiography at 6 months. The restenosis rate assessed by quantitative angiography was 24%; no cases of reocclusion were observed. These angiographic results were accompanied with a significant improvement of the anginal symptoms (p < 0.01). These results suggest that stent implantation following recanalization of a coronary occlusion may be beneficial on the restenosis and reocclusion rates and anginal symptoms. However, they should be confirmed by randomised study. It would also be important to analyse the impact of this procedure on the outcome of left ventricular function.

Effect of pravastatin on angiographic restenosis after coronary balloon angioplasty. The PREDICT Trial Investigators. Prevention of Restenosis by Elisor after Transluminal Coronary Angioplasty

OBJECTIVES

This study sought to determine whether pravastatin affects clinical or angiographic restenosis after coronary balloon angioplasty.

BACKGROUND

Experimental data and preliminary clinical studies suggest that lipid-lowering drugs might have a beneficial effect on restenosis after coronary angioplasty.

METHODS

In a multicenter, randomized, double-blind trial, 695 patients were randomized to receive pravastatin (40 mg/day) or placebo for 6 months after successful balloon angioplasty. All patients received aspirin (100 mg/day). The primary angiographic end point was minimal lumen diameter (MLD) at follow-up, assessed by quantitative coronary angiography. A sample size of 313 patients per group was required to demonstrate a difference of 0.13 mm in MLD between groups (allowing for a two-tailed alpha error of 0.05 and a beta error of 0.20). To allow for incomplete angiographic follow-up (estimated lost to follow-up rate of 10%), 690 randomized patients were required. Secondary end points were angiographic restenosis rate (restenosis assessed as a categoric variable, > 50% stenosis) and clinical events (death, myocardial infarction, target vessel revascularization).

RESULTS

At baseline, clinical, demographic, angiographic and lipid variables did not differ significantly between groups. In patients treated with pravastatin, there was a significant reduction in total and low density lipoprotein cholesterol and triglyceride levels and a significant increase in high density lipoprotein cholesterol levels. At follow-up the MLD (mean +/- SD) was 1.47 +/- 0.62 mm in the placebo group and 1.54 +/- 0.66 mm in the pravastatin group (p = 0.21). Similarly, late loss and net gain did not differ significantly between groups. The restenosis rate (recurrence > 50% stenosis) was 43.8% in the placebo group and 39.2% in the pravastatin group (p = 0.26). Clinical restenosis did not differ significantly between groups.

CONCLUSIONS

Although pravastatin has documented efficacy in reducing clinical events and angiographic disease progression in patients with coronary atherosclerosis, this study shows that it has no effect on angiographic outcome at the target site 6 months after coronary angioplasty.

Restenosis rates in diabetic patients: a comparison of coronary stenting and balloon angioplasty in native coronary vessels

BACKGROUND

Diabetes is a major risk factor for restenosis after coronary balloon angioplasty. Recent studies have shown that coronary stenting significantly reduces restenosis compared with balloon angioplasty alone. However, limited information is available on the effect of coronary stenting in diabetic patients.

METHODS AND RESULTS

We designed this study to analyze the effect of diabetes on restenosis in patients treated with either balloon angioplasty or coronary stenting who were enrolled in a 6-month angiographic follow-up program. Three hundred consecutive patients, 19% of whom were diabetics, who underwent coronary stent implantation during a single-vessel procedure on native coronary vessels and who had 6-month angiographic follow-up constituted the study group (stent group). Three hundred consecutive patients who underwent 6-month angiographic follow-up after single-vessel conventional balloon angioplasty served as control patients (balloon group). Preprocedural, postprocedural, and follow-up angiograms were analyzed with quantitative angiography. In the balloon group, the restenosis rate was almost twofold higher in diabetic than in nondiabetic patients (63% versus 36%; P=.0002) owing to both a greater late loss (0.79+/-0.70 versus 0.41+/-0.61 mm, respectively; P<.0001) and a higher rate of late vessel occlusion (14% versus 3%, respectively; P<.001). In the stent group, restenosis rates were similar in diabetics and nondiabetics (25% versus 27%, respectively). Furthermore, in the stent group, late loss (0.77+/-0.65 versus 0.79+/-0.57 mm, respectively) and the rate of late vessel occlusion (2% versus 1%, respectively) did not differ significantly between diabetic and nondiabetic patients.

CONCLUSIONS

Although diabetics have increased rates of restenosis and late vessel occlusion after simple balloon angioplasty, they have the same improved outcome with coronary stenting that has been documented in nondiabetic patients.

D allele of the angiotensin I-converting enzyme is a major risk factor for restenosis after coronary stenting

BACKGROUND

Although intracoronary stent implantation significantly reduces restenosis compared with balloon angioplasty, a minority of patients still develop restenosis predominantly due to neointimal hyperplasia. Experimental studies suggest that the renin-angiotensin system is involved in neointimal hyperplasia after arterial injury. In humans, the plasma and cellular levels of ACE are associated with an I/D genetic polymorphism in the ACE gene, DD patients having higher levels.

METHODS AND RESULTS

We investigated a possible relation between the ACE I/D polymorphism and restenosis in 146 patients who underwent successful implantation of a Palmaz-Schatz stent and had 6-month follow-up angiography. The minimal lumen diameter (MLD) before and after the procedure did not differ significantly among the three groups of genotypes (DD, ID, and II). At follow-up, MLD had a significant inverse relationship to the number of D alleles present (DD, 1.65 +/- 0.71 mm; ID, 1.84 +/- 0.60 mm; II, 2.05 +/- 0.61 mm; P < .007). Late luminal loss during the follow-up period was significantly related to the number of D alleles (DD, 0.89 +/- 0.61 mm; ID, 0.60 +/- 0.52 mm; II, 0.40 +/- 0.53 mm; P < .0001). The relative risk of restenosis (defined as a > 50% diameter stenosis at follow-up) approximated by the adjusted odds ratio was 2.00 per number of D alleles (95% confidence interval, 1.03 to 3.88, P < .04).

CONCLUSIONS

The ACE I/D polymorphism influences the level of late luminal loss after coronary stent implantation. These results suggest that the renin-angiotensin system may be implicated in the pathogenesis of restenosis after coronary stenting.

The angiotensin II type 1 receptor gene polymorphism is associated with coronary artery vasoconstriction

OBJECTIVES

This study sought to assess the potential association of the angiotensin-converting enzyme (ACE) and angiotensin II type 1 (AT1) receptor gene polymorphisms on coronary vasomotion in humans.

BACKGROUND

Abnormal coronary vasomotion plays a role in the clinical expression of coronary atherosclerosis. The components of the renin-angiotensin system are important determinants of vasomotor tone. Furthermore, epidemiologic evidence suggests that these components are involved in the pathogenesis of coronary artery disease. Indeed, two genetic polymorphisms of the ACE and AT1 receptor genes were synergistically associated with the occurrence of myocardial infarction. The influence of these genetic polymorphisms on the risk of myocardial infarction may be related, at least in part, to a deleterious effect on coronary vasomotion.

METHODS

We studied the response of angiographically normal human coronary arteries after intravenous injection of methylergonovine maleate, a potent vasoconstrictor whose effects have been previously explored in various aspects of coronary artery disease. We characterized the ACE and AT1 receptor genotypes in a consecutive series of 140 patients with normal coronary arteries. Coronary vasomotion was assessed with quantitative coronary angiography.

RESULTS

No effect of the ACE gene polymorphism was detected. Conversely, the patients carrying the AT1 receptor CC genotype (n = 13) had significantly greater vasoconstriction in distal coronary vessels (p < 0.009).

CONCLUSIONS

The AT1 receptor gene polymorphism is associated with coronary vasomotion in humans.

ACE inhibition accelerates endothelial regrowth in vivo: a possible explanation for the benefit observed with ACE inhibitors following arterial injury

Recent in vitro studies suggest that angiotensin converting enzyme (ACE) inhibitors stimulate endothelial cell proliferation and migration. The present study was designed to test the hypothesis that an ACE inhibitor may accelerate endothelial regrowth in vivo. Twenty eight New Zealand White rabbits were randomized to receive placebo or the ACE inhibitor perindopril and underwent iliac balloon denudation. Endothelial regrowth, quantified 28 days after injury using Evans blue, was significantly greater in perindopril-treated animals than in controls (131 +/- 9 mm2 vs 69 +/- 8 mm2; P < .001). These results were confirmed by scanning electron microscopy and by specific immunostaining for endothelial cells. These data provide the first in vivo demonstration that ACE inhibitors accelerate endothelial regrowth after arterial injury. This effect may contribute to the benefit observed with ACE inhibition following arterial injury.

Restenosis after coronary angioplasty for rapidly progressive coronary stenosis

OBJECTIVES

We hypothesized that percutaneous transluminal coronary angioplasty performed on coronary stenoses that have demonstrated rapid angiographic progression would be associated with a high risk of restenosis.

BACKGROUND

High rates of restenosis have been documented after percutaneous transluminal coronary angioplasty of unstable lesions and of lesions that recur rapidly after a successful initial angioplasty. This suggests that the "activity' of the plaque at the time of angioplasty may be an important factor determining the risk of restenosis.

METHODS

In our institution we recommend angiographic follow-up for all patients with successful percutaneous transluminal coronary angioplasty. In this way we identified 86 consecutive patients who, at the time of angiographic follow-up had not developed restenosis at the dilated site, but required a further percutaneous transluminal coronary angioplasty at a different site. (which was successful). Based on quantitative angiographic measurements, 45 of these lesions (rapidly progressive lesions) had significantly increased in severity in the interval between the two angiograms (7.7 +/- 3.3 months) while 41 (stable lesions) had not. Rapid progression was defined as a > 0.4 mm decrease in minimal lumen diameter between initial angiography and percutaneous transluminal coronary angioplasty. All 86 patients had further angiographic follow-up 6 months later.

RESULTS

Baseline clinical and angiographic variables were similar in both groups except that a higher proportion of patients in the rapid progression group had unstable angina (20% vs 5%; P < 0.05). Late loss during follow-up did not differ statistically between groups (0.31 mm) and minimal lumen diameter at follow-up was also similar (stable lesion group = 1.40 +/- 0.48 mm; rapidly progressive lesion group = 1.30 +/- 0.59 mm). The loss index (late loss divided by acute gain) was also similar in both groups (0.45 +/- 0.52 in the stable lesion group, 0.37 +/- 0.76 in the rapidly progressive lesion group). A strong correlation between acute gain and late loss was observed in the stable lesion group (r = 0.61; P < 0.0001); by contrast, there was no relationship between these two variables in the rapidly progressive lesion group (r = 0.20; P = 0.19).

CONCLUSIONS

Percutaneous transluminal coronary angioplasty in patients with unstable angina or with early recurrence after a first percutaneous transluminal coronary angioplasty is associated with an increased risk of restenosis. By contrast, this study shows that angiographic instability, as evidenced by rapid stenosis progression, has no deleterious effect on the occurrence of restenosis. Percutaneous transluminal coronary angioplasty thus appears as a reasonable therapeutic option for coronary stenoses that have demonstrated rapid angiographic progression in the months prior to the procedure.

Morphological changes after percutaneous transluminal coronary angioplasty of unstable plaques. Insights from serial angioscopic follow-up

OBJECTIVE

To describe the morphological changes occurring in the months following percutaneous transluminal coronary angioplasty (PTCA) of unstable plaques.

BACKGROUND

Coronary angioscopy is a relatively new technique to assess plaque morphology. Previous angioscopic studies have shown that unstable coronary lesions are characterized by complex morphology, evidence of plaque rupture, and intraluminal thrombi. No serial angioscopic studies have investigated the effects of PTCA on plaque morphology at such lesions.

METHODS

We studied 15 patients who underwent successful PTCA for an unstable coronary syndrome (unstable angina: n = 5; recent myocardial infarction: n = 10). Angioscopy was performed immediately before PTCA in 14 patients, immediately after PTCA in 13 patients, and at follow-up (225 +/- 62 days after PTCA) in all patients.

RESULTS

Pre-PTCA, plaque morphology was defined as complex in 18%, ulcerated in 27%; the vessel was totally occluded in 18% of cases. Plaque colour was yellow in 75% of patients. A thrombus was identified at the lesion site in 71% of patients. Immediately post-PTCA, small surface disruptions and dissections were observed in 62% of patients. Plaque colour was yellow in 85% of cases. Seventy-seven percent of patients had an angioscopically visible thrombus at the PTCA site. At follow-up, however, plaque shape was almost uniformly classified as smooth concentric (93%); plaque colour was white in 93%; no thrombus was observed.

CONCLUSIONS

These results demonstrate the healing of unstable plaques in the months following PTCA. The angioscopic appearance at 6 months is that of a stable plaque (smooth concentric, white, without thrombus). Whether this stable angioscopic appearance predicts long-term clinical stability remains to be determined.

Combined antiplatelet therapy with ticlopidine and aspirin. A simplified approach to intracoronary stent management

Intravascular metallic stents are increasingly used in the non-surgical management of coronary atherosclerosis. Despite intensive anticoagulation, subacute stent thrombosis, which usually has serious clinical consequences, and major haemorrhagic complications remain major problems after stent implantation. In addition, conventional management with anticoagulant therapy requires prolonged hospitalization. In a prospective multicentre study, we investigated the efficacy of a combination of two antiplatelet agents, ticlopidine 500 mg daily and aspirin 200 mg daily, without oral anticoagulation after stent implantation. Since November 1993, 529 consecutive patients, in whom 545 vessels were successfully stented with conventional (non-heparin coated) stents have been enrolled. Stenting was performed as a bailout procedure for failed angioplasty in 112 patients, for a suboptimal result after angioplasty in 314 patients, and electively in the remaining 103 patients. Coronary events related, or possibly related, to stent thrombosis occurred in 5.4% of patients stented as a bailout procedure and in 1.8% of patients stented for a suboptimal result. Serious bleeding complications occurred in 5.4% of patients stented as a bailout procedure and 1.5% of patients stented for a suboptimal result. Neither stent thrombosis nor serious bleeding complications were seen in patients stented electively. Ticlopidine therapy was discontinued in 1.9% of patients due to neutropenia (0.6%) or rash (1.3%). Mean hospital stay decreased from 6.16 +/- 2.14 days to 4.2 +/- 2.15 days during the study period. A combination of two antiplatelet agents can be employed in the vast majority of patients after coronary stent implantation. Subacute stent thrombosis rates and bleeding complications compare favourably with those reported using conventional therapy and the duration of hospitalization is reduced.

Hypersensitivity of human coronary segments to ergonovine 6 months after injury by coronary angioplasty: a quantitative angiographic study in consecutive patients undergoing single-vessel angioplasty

OBJECTIVE

Multiple studies have been designed to analyse restenosis angiographically but few have studied the vasoreactivity of coronary segments subjected to angioplasty a few months before. In the present study we analysed, with use of quantitative angiography, the vasoreactivity of previously dilated segments to graded doses of ergonovine and of isosorbide dinitrate.

PATIENTS

Fifty consecutive patients undergoing follow-up angiography 6 months after a single coronary angioplasty procedure were studied.

RESULTS

The vasoconstrictor response at dilated segments (-19.3 +/- 3.0%) was significantly greater than at control proximal and distal sites in dilated (-7.3 +/- 1.1%, -11.0 +/- 2.9%) and non-dilated (-9.1 +/- 1.3%, -8.3 +/- 2.2%) vessels for the lowest dose of ergonovine (100 micrograms). The constrictor response to 100 micrograms ergonovine (-20.2 +/- 5.3%) at restenosed segments (> 50% stenosis, n = 18) was similar to that (-18.8 +/- 3.8%) at non-restenosed sites (n = 32). In contrast, the degree of constrictor response was similar in all segments including dilated segments for the highest dose of ergonovine used. All segments dilated significantly after intracoronary injection of isosorbide dinitrate.

CONCLUSION

Our results demonstrate hypersensitivity of the dilated site to ergonovine 6 months after angioplasty at both restenosed and non-restenosed sites. This response may reflect partial dysfunction of endothelium that has regenerated after injury or hypersensitivity of vascular smooth muscle cells at the site of arterial injury.

NO synthesis is involved in structural and functional effects of ACE inhibitors in injured arteries

Angiotensin-converting enzyme (ACE) inhibitors reduce intimal hyperplasia after balloon injury. A role for nitric oxide (NO) has been suggested in this effect. Because recent data suggest that NO may modulate some features of endothelial cells and because endothelial cells are involved in the control of intimal hyperplasia, we investigated the role of NO synthesis in the effect of an ACE inhibitor, perindopril, on neoendothelial dysfunction and intimal hyperplasia in a rabbit model of unilateral iliac balloon injury. New Zealand White male rabbits received placebo, perindopril, or cotreatment with perindopril and NG-nitro-L-arginine methyl ester (L-NAME) and were evaluated 4 wk after the injury. Fifteen rabbits (5 in each group) were used to assess in vitro vasoreactivity and twenty-four (8 in each group) for morphometric analysis. In injured vessels, neoendothelium-dependent relaxation in ACE inhibitor-treated animals was improved compared with placebo (P < 0.05) and restored to the level of noninjured vessels (NS). The improvement observed with ACE inhibitor was abolished by cotreatment with L-NAME (P < 0.05). In the same vessels, no effect was observed on neoendothelium-independent vasoreactivity. The improved neoendothelial dysfunction with ACE inhibitor was associated with a 66% reduction in intimal thickening (P < 0.01). The effect was also reversed by cotreatment with L-NAME (P < 0.01). In noninjured vessels, treatment did not alter vasoreactivity or morphology of the vessel wall. These results suggest that NO synthesis may play a key role in the improvement of vascular function seen with ACE inhibitor in balloon-injured vessels.

Relation of coronary angioscopic findings at coronary angioplasty to angiographic restenosis

BACKGROUND

Discordant results have been reported regarding morphological predictors of restenosis after percutaneous transluminal coronary angioplasty (PTCA). These discrepancies may be related to the limitations of angiography in the study of plaque morphology.

METHODS AND RESULTS

We studied 117 consecutive patients who underwent successful PTCA and who underwent coronary angioscopy before and immediately after the procedure. Angiographic follow-up was performed in 99 (85%) patients. We analyzed the relationship between angioscopic variables at the time of PTCA and the occurrence of restenosis assessed by quantitative coronary angiography. Plaque shape and color had no effect on late loss in luminal diameter (late loss: smooth lesions, 0.55 +/- 0.68 mm; complex lesions, 0.76 +/- 0.60 mm; white plaques, 0.51 +/- 0.56 mm; yellow plaques, 0.65 +/- 0.72 mm; P = NS). An angioscopic protruding thrombus at the PTCA site was associated with significantly greater loss in luminal diameter (late loss: no thrombus, 0.47 +/- 0.54 mm; lining thrombus, 0.59 +/- 0.67 mm; protruding thrombus, 1.07 +/- 0.77 mm; P < .05). Dissection assessed by angioscopy immediately after PTCA had no effect on late loss in luminal diameter (late loss: no dissection, 0.60 +/- 0.60 mm; simple dissection, 0.82 +/- 0.75 mm; complex dissection, 0.57 +/- 0.80 mm; P = NS).

CONCLUSIONS

These results show that coronary angioscopy may be helpful in predicting the risk of restenosis after PTCA. The high rate of angiographic recurrence observed when PTCA is performed at thrombus-containing lesions supports a role for thrombus in the process of luminal renarrowing after PTCA.

[Coronary endovascular prostheses (stents) in the treatment of imminent or acute occlusion as a complication of coronary angioplasty]

Acute coronary occlusion as a consequence of dissection or thrombosis occurs in 2 to 11% of patients treated with percutaneous transluminal coronary angioplasty (PTCA), and continues to be the principal cause of early morbidity and mortality. In this study the experience of one center is presented with the application of two types of stents, Wiktor (Medtronic Inc.) or Gianturco-Roubin (Cook Inc.) for bailout of acute or threatening coronary occlusion that persisted after treatment with prolonged balloon inflation. All patients received a complete anticoagulation scheme with heparin, dextran, dipyridamole, aspirin and coumadin. From January to November 1993, 26 patients with 27 prosthesis were included. There were 21 men and 5 women with mean age of 58 years (range 36 to 73). The indications for stenting were: total occlusion in five (19%) threatening occlusion in 13 (50%) and severe persistent dissection in eight (31%). Initial implantation success was 93% (25/27). Procedure related clinical complications were death in one patient, bypass surgery in two (8%) and myocardial infarction in four (15%). Acute stent thrombosis occurred in three cases and subacute in one (11 and 4% respectively). Three patients, had non-fatal bleeding complications. Final clinical success without myocardial infarction, bypass surgery or death was 77%. In conclusion, coronary stenting for bailout of acute or threatening coronary occlusion after PTCA is a good alternative to emergency surgery. New antithrombotic strategies and better anticoagulation schemes may improve further this procedure.

Relation between the deletion polymorphism of the angiotensin-converting enzyme gene and late luminal narrowing after coronary angioplasty

BACKGROUND

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been implicated in the pathogenesis of coronary artery disease. The deletion allele is strongly associated with the level of circulating ACE and is a potent risk factor for myocardial infarction. Recently, the deletion allele was also associated with the occurrence of visually diagnosed restenosis after percutaneous transluminal coronary angioplasty (PTCA) in a selected population of patients with acute myocardial infarction.

METHODS AND RESULTS

We investigated the influence of the ACE I/D polymorphism on the occurrence of restenosis after PTCA with the use of quantitative coronary angiography. ACE I/D genotypes were characterized in 118 consecutive patients who had one-vessel disease and were undergoing systematic angiographic follow-up. Coronary angiograms were analyzed before and after PTCA and at follow-up (7.4 +/- 3.0 months). Before PTCA, there were no clinical or angiographic differences among the three groups of genotypes (DD, n = 39; ID, n = 62; II, n = 17). After PTCA, the mean differences in minimal luminal diameter between post-PTCA and pre-PTCA angiograms (acute gain) were identical in the three groups, as was the mean percent residual stenosis. At follow-up angiography, the mean difference in minimal coronary luminal diameter between post-PTCA and follow-up angiograms (late loss) was not significantly different in the three groups of genotypes. The percentage of patients with restenosis defined as a > 50% stenosis was identical in the three groups.

CONCLUSIONS

In this quantitative study, the I/D polymorphism of the ACE gene had no influence on the occurrence of restenosis after coronary angioplasty.

Restenosis after coronary angioplasty

The major disadvantage of using percutaneous transluminal coronary angioplasty to treat patients with atherosclerotic coronary disease is the frequent occurrence of restenosis after an initially successful procedure. Studies in animals and histological observations in man have demonstrated that restenosis is characterized by neointimal hyperplasia due to smooth muscle cell proliferation and to the synthesis of extracellular matrix. Improvements in technology or pharmacological interventions have had no significant impact on the rate of restenosis. In spite of our increased understanding of the molecular mechanisms of restenosis. no effective treatment is available at the present time. Gene therapy, which has produced encouraging initial results in experimental models, may provide a solution in the medium term.

[Percutaneous coronary angioscopy: 200 observations in 100 candidates for angioplasty]

Due to the recent technological advances, it is possible to perform percutaneous coronary angioscopy in a straightforward fashion in most patients. To know the safety and usefulness of this technique we present 200 observations in 100 patients candidates for coronary intervention. We used a coronary angioscope (Baxter, Edwards LIS Division), that can be placed using the conventional technique for percutaneous coronary angioplasty. The system incorporates a proximal occluding balloon, and distally a movable optical fiber. Case selection considered non-ostial coronary segments relatively straight. It was possible to obtain adequate images in 86 percent of cases. The technique is safe in experienced hands: there were two cases of ventricular fibrillation, and two cases of local dissection occurred, none of these associated with clinical consequences. No myocardial infarction, surgery or death, related to this procedure occurred. Valuable diagnostic information is derived from angioscopy as the method provides some histopathological correlation. Stable plaques are usually uniformly white or yellow. Unstable plaques are yellow and ulcerated. Thrombus can be easily recognized in acute coronary syndromes. Also in percutaneously treated segments, the final result and the presence of dissection or hemorrhage can be visualized. Coronary percutaneous angioscopy is safe and brings useful clinical information. Its applications in the clinical practice are still to be determined.

Two-pronged antiplatelet therapy with aspirin and ticlopidine without systemic anticoagulation: an alternative therapeutic strategy after bailout stent implantation

BACKGROUND

Intracoronary stent implantation for failed angioplasty is associated with a relatively high incidence of coronary and peripheral complications. On the basis of previous clinical and experimental data, we investigated a protocol of intensive antiplatelet therapy, with aspirin (200 mg) and ticlopidine (500 mg), without oral anticoagulation, and with only periprocedural heparin, after stent implantation.

METHODS

Between November 1993 and May 1994, 650 patients underwent balloon angioplasty in our institution. Stent implantation was attempted in 45 patients because of acute (58%) or threatened acute (22%) closure, or because the result of the primary angioplasty was inadequate (9%).

RESULTS

Stents were successfully implanted in 42 (93%) patients. Two patients were not enrolled in the protocol (referring physician preference in one, metallic heart valve prosthesis in the other). In the remaining 40 patients, two sustained Q-wave infarctions and three sustained non Q-wave infarctions, which were already established at the time of stent implantation. No further clinical events occurred during hospitalization. During follow-up (mean 3.2 months) none of the patients died and none developed unstable angina or myocardial infarction. Ticlopidine-related rash occurred in two patients who were consequently put on warfarin therapy instead.

CONCLUSIONS

Antiplatelet therapy with ticlopidine and aspirin, without systemic anticoagulation, appears to be a promising alternative to the classical approach with heparin and warfarin therapy, which requires intensive biological monitoring. This approach considerably simplifies patient management, and it could reduce the need for prolonged hospitalization.

Restenosis after delayed coronary angioplasty of the culprit vessel in patients with a recent myocardial infarction treated by thrombolysis

BACKGROUND

Clinical follow-up after percutaneous transluminal coronary angioplasty (PTCA) of an infarct-related lesion has demonstrated a low incidence of recurrent symptoms and repeated revascularization. In the absence of systematic angiographic follow-up, this low rate of clinical restenosis may reflect either a truly lower incidence of anatomic restenosis or the lack of recurrent symptoms in patients with extensive infarction in the territory of the restenotic vessel.

METHODS AND RESULTS

We studied 300 consecutive patients who, after a thrombolysis for myocardial infarction, underwent delayed (10.5 +/- 6 days after the myocardial infarction) PTCA of the infarct-related lesion. Procedural success was obtained in 253 patients (84%), and angiographic follow-up was performed in 205 of this group (81%) at a mean of 7.3 +/- 1.9 months. Restenosis (defined as the recurrence of > 50% stenosis) was present in 105 patients (51%). Only 34 of the 105 patients (32%) with angiographic restenosis were symptomatic; the other 68% had clinically silent restenosis. Of these 105 patients, 27 (13% of the total population undergoing follow-up angiography) had reocclusion at the dilated site at follow-up. The severity of the stenosis at follow-up and the late loss in minimal lumen diameter followed a nearly Gaussian distribution if the lesions that were totally occluded at follow-up were excluded. By multivariate analysis, two independent predictors of reocclusion were identified: a small reference diameter (P < .0005) and the presence of collateral vessels before the procedure (P < .01). Only one factor was associated with restenosis in the 178 patients who did not have reocclusion at follow-up; a Thrombolysis in Myocardial Infarction grade < or = 2 before the procedure (P < .0001). At follow-up, there was a significantly (P < .01) higher ejection fraction in patients without restenosis (56.1 +/- 13.4%) and in patients with restenosis without total occlusion (56.0 +/- 13.8%) than in patients with reocclusion (46.4 +/- 13.0%).

CONCLUSIONS

Despite a satisfactory clinical outcome, delayed PTCA of an infarct-related lesion is associated with a high rate of angiographic recurrence. Two distinct mechanisms account for recurrent stenosis: progressive luminal renarrowing as documented after angioplasty of stable lesions and reocclusion of the infarct-related lesion. Only reocclusion is associated with a deterioration in left ventricular function at follow-up.

Local lesion-related factors and restenosis after coronary angioplasty. Evidence from a quantitative angiographic study in patients with unstable angina undergoing double-vessel angioplasty

BACKGROUND

Restenosis rates are high when coronary angioplasty is performed in patients with unstable angina. The relative contributions of local and systemic factors to this excess risk of restenosis are unclear. To assess these, we compared changes in minimal lumen diameter and the incidence of restenosis, determined by quantitative coronary angiography, after coronary angioplasty at culprit and nonculprit lesions dilated in the course of a single procedure in patients with unstable angina.

METHODS AND RESULTS

We identified 67 consecutive patients with unstable angina in whom two lesions, in different vessels, were dilated during the same procedure. Lesions were designated as culprit or nonculprit on the basis of the location of ECG changes during chest pain combined with assessment of the angiographic characteristics of the lesions. With these criteria, 43 patients had identifiable culprit lesions. Stenosis severity before and immediately after angioplasty and at follow-up was assessed with quantitative angiography. Angiographic follow-up was performed in 91% (39 patients) of this subgroup. Culprit lesions were more severe (P < .02) than nonculprit lesions. The late loss at culprit lesions (0.87 +/- 0.75 mm) was significantly (P < .01) greater than the equivalent value for nonculprit lesions (0.33 +/- 0.69 mm). With a categorical definition (> 50% stenosis at follow-up), restenosis occurred at 67% of culprit lesions and at 32% of nonculprit lesions (P < .01).

CONCLUSIONS

The greater loss in minimal lumen diameter and the consequent higher rate of restenosis at culprit compared with nonculprit lesions suggest that local "lesion-related" factors are an important determinant of the high rate of restenosis when coronary angioplasty is performed in patients with unstable angina.

Angiotensin converting enzyme inhibition prevents proto-oncogene expression in the vascular wall after injury

OBJECTIVES

Angiotensin converting enzyme (ACE) inhibitors reduce neointimal hyperplasia after balloon denudation, but the mechanisms are not completely understood. It has been demonstrated that nuclear oncogenes are induced in the vascular wall in the hours immediately after injury, and that the same genes are induced by angiotensin II in vascular smooth muscle cells. It has therefore been suggested that the effects of ACE inhibitors on the response of the vessel wall could be mediated by an inhibition of proto-oncogene expression.

METHODS AND RESULTS

Sixteen New Zealand White rabbits were randomly assigned for histologic analysis to receive placebo (n = 9) or 1 mg/kg per day perindopril (n = 7). After treatment for 7 days balloon aortic injury was performed. The treatment was continued and the rabbits were killed 28 days after injury. In the perindopril group the neointimal cross-sectional area was significantly smaller than in the control group. Six untreated rabbits were used to assess the time course of proto-oncogene expression in the aortic wall after injury in the present model. After extraction, total aortic RNA was hybridized with myc, fos and jun probes. Based on the results, the effects of ACE inhibition on proto-oncogene expression were tested 1 h after balloon denudation. Accordingly, 24 rabbits were randomly assigned to pretreatment for 7 days with placebo or with 1 or 10 mg/kg per day perindopril (n = 8, for each group) and were killed 1 h after injury. Expression of c-myc was not altered by pretreatment. However, 1 mg/kg per day perindopril induced significant reductions of 50% in c-jun and 45% in c-fos expression compared with control. No additional effect was obtained with the higher dose.

CONCLUSION

The effect of ACE inhibition on intimal hyperplasia is associated with a reduction in early cellular events such as c-fos and c-jun expression. These results suggest that potent ACE inhibition at the time of vascular injury may be required to limit the hyperplastic response of the vessel wall.

Neointimal thickening after balloon denudation is enhanced by aldosterone and inhibited by spironolactone, and aldosterone antagonist

OBJECTIVE

The aim was to examine the effects of aldosterone and of an aldosterone antagonist, spironolactone, on neointimal thickening in a rabbit model of balloon injury.

METHODS

Eighteen rabbits underwent aortic and iliac balloon injury and were randomised to subcutaneous infusion of aldosterone (70 micrograms.kg-1.d-1) or vehicle solution for 28 d. Eighteen other rabbits were randomised to receive daily subcutaneous injections of spironolactone (50 mg.kg-1.d-1) or of vehicle for 7 d before injury and for 28 d after the procedure. All animals were then killed just after measurement of plasma renin activity and of arterial pressure. Vessels were fixed and five cross sections were analysed per rabbit (three aortic; two from iliac artery). Mean values of neointimal area and of the neointimal area/medial area ratio were calculated.

RESULTS

Aldosterone treatment was associated with a decrease in renin activity and a non-significant increase in mean arterial pressure. Aldosterone significantly augmented the neointimal thickening in the iliac artery [0.42(SEM 0.07) v 0.24(0.03) mm2, P < 0.05] but not in the aorta [0.63(0.08) v 0.59(0.12) mm2, NS]. Spironolactone significantly inhibited intimal thickening, both in the iliac artery [0.09(0.02) v 0.29(0.01) mm2, P < 0.001] and in the aorta [0.31(0.03) v 0.59(0.06) mm2, P < 0.001]. Spironolactone administration was associated with an increase in renin activity and a decrease in mean arterial blood pressure.

CONCLUSIONS

Aldosterone administration enhances neointimal thickening after injury and spironolactone, an aldosterone antagonist, is a potent inhibitor of neointimal thickening in the same model. This suggests a role for aldosterone in the pathophysiology of neointimal proliferation after balloon injury and for aldosterone antagonists in its prevention.

Evidence for time-dependent activation of monocytes in the systemic circulation in unstable angina but not in acute myocardial infarction or in stable angina

BACKGROUND

Platelet activation plays a pivotal role in the pathogenesis of acute coronary disease. Monocytes are involved in the progression of atherosclerosis and are potent activators of blood coagulation through their ability to synthesize tissue factor (TF). The aim of this study was to compare markers of monocyte and coagulation activation in the systemic blood of patients with unstable angina, acute myocardial infarction, or stable angina.

METHODS AND RESULTS

We studied 26 patients with unstable angina (10 +/- 5 hours after the onset of the last episode of pain), 18 patients with acute myocardial infarction (5 +/- 4 hours after the onset of pain), and 34 patients with stable angina. We measured levels of TF expression in peripheral blood mononuclear cells (isolated by gradient centrifugation and incubated for 16 hours, with or without endotoxin stimulation), levels of plasma prothrombin fragment 1 + 2 (F1 + 2), and levels of fibrinogen in peripheral blood. In patients with unstable angina, both stimulated and unstimulated cells exhibited higher levels of TF expression than in patients with stable angina (P = .0001). In patients with acute myocardial infarction, monocyte TF activity did not differ from that in patients with stable angina. Mean levels of F1 + 2 and of fibrinogen did not differ significantly between groups. Only in the unstable angina group, a modest correlation was found between fibrinogen (r = .72, P = .005) and F1 + 2 levels (r = .54, P = .001) levels and the degree of monocyte TF expression. In patients with unstable angina, monocyte TF expression (both stimulated and unstimulated, assessed by biological activity and by antigen techniques) and fibrinogen levels were correlated with the time elapsed from the beginning of the most recent episode of pain (.61 < r < .72, .02 < P < .0001). By contrast, there was no correlation between these variables and the time from onset of pain in patients with acute myocardial infarction.

CONCLUSIONS

A time-dependent activation of systemic monocytes and a time-dependent increase in fibrinogen levels occurs in unstable angina but not in myocardial infarction. These findings provide further evidence that a specific inflammatory process occurs in unstable angina. Further studies are required to determine whether monocyte activation is a cause or a consequence of plaque instability in patients with unstable angina and to clarify the interrelations between platelet and monocyte activation in these circumstances.

Long-term oral administration of L-arginine reduces intimal thickening and enhances neoendothelium-dependent acetylcholine-induced relaxation after arterial injury

BACKGROUND

Nitric oxide (NO), in addition to its potent vasorelaxant properties, may participate in growth regulation of cultured smooth muscle cells. It was recently demonstrated that in vivo endothelial injury induces the production of NO from L-arginine in the arterial wall.

METHODS AND RESULTS

We studied the effects of long-term administration of L-arginine, the precursor of NO, on neointimal thickening and on neoendothelium-dependent vasorelaxation 4 weeks after balloon denudation of normocholesterolemic rabbit iliac arteries. Rabbits were fed with either a standard diet or a diet supplemented with L-arginine (2.25%) in their drinking water 3 days before and during 4 weeks after balloon denudation. The effectiveness of L-arginine supplementation was confirmed by measurement of plasma arginine levels. L-Arginine had no effect on hemodynamic parameters. All animals were killed 4 weeks after balloon denudation, and a digital histomorphometric analysis of three serial nonconsecutive histological cross sections per iliac artery was performed. Intimal thickening was reduced (P < .05) from 0.43 +/- 0.08 (SE) mm2 in controls (n = 8) to 0.24 +/- 0.02 mm2 in treated animals (n = 8). Ten animals (n = 5 in each group) were used for in vitro vasoreactivity assessment 4 weeks after balloon denudation. Neoendothelium-dependent acetylcholine-induced relaxation (10(-8) mol/L to 3.10(-5) mol/L) in treated animals (Emax = -24.1 +/- 5.5%) was significantly greater than in controls (Emax = -8.9 +/- 2.2%). Endothelium-independent relaxation did not differ between groups (Emax = -58.1 +/- 6.5% in L-arginine-supplemented animals versus -52.9 +/- 6.8% in controls).

CONCLUSIONS

Our results demonstrate that L-arginine, a precursor of NO, reduces neointimal thickening after balloon denudation and improves neoendothelial-dependent acetylcholine-induced relaxation.