Long term follow-up of "full metal jacket" of de novo coronary lesions with new generation Zotarolimus-eluting stents.

BACKGROUND: Diffuse coronary artery disease treatment still remains a challenge for interventional cardiologists and cardiac surgeons. There are few data on full metal jacket (FMJ) stenting, especially with new-generation drug-eluting stents. We aimed to assess the efficacy and safety of FMJ with new-generation Zotarolimus-eluting stents (n-ZES). METHODS AND RESULTS: All patients who underwent FMJ with n-ZES (≥60mm stent length) in eleven Italian interventional centers participating in the Clinical Service® project were included in this analysis. The project population consisted of 120 patients and 122 lesions. Mean age was 67±10years and 95 (79.2%) patients were male. A chronic total occlusion was present in 34 lesions (27.9%). The number of stents implanted per lesion was 2.9±0.8, and the diameter of the stents was 3.0±0.5mm. Predilation and post-dilatation were performed in 107 (87.7%) and 92 (75.4%) patients, respectively. At 41±21month follow-up there were 2 patients with subacute definite stent thrombosis, 6 patients (5.0%) had cardiac death and 5 patients (4.2%) had non-fatal myocardial infarction. Seven patients (5.8%) underwent clinically-driven target lesion revascularization. Fourteen patients (11.7%) had at least one major adverse cardiac event. CONCLUSION: The treatment of diffuse coronary artery disease with FMJ stenting with n-ZES appears to be effective and safe. Late and very-late ST does not seem to be an issue and the rate of restenosis and of major cardiac adverse events after more than 3-year follow-up is rather low.

Prospective multicentre clinical performance evaluation of second and third generation zotarolimus-eluting stents to treat patients with bifurcated coronary lesions.

AIM: To assess the "real world" clinical outcome of patients with bifurcated lesions undergoing percutaneous coronary intervention with implantation of second and third generations of zotarolimus-eluting stent. METHODS AND RESULTS: Nine Italian centres participated in a prospective multicentre clinical project evaluating the outcome of patients receiving zotarolimus-eluting Resolute stent and Resolute Integrity stents. Patients with bifurcated lesions entered this evaluation. Clinical characteristics and angiographic and procedural details were prospectively recorded. Clinical outcome was prospectively assessed to evaluate the occurrence of major adverse cardiac events (MACE). A total of 577 patients were enrolled. The target lesion was distal left main in 11.1% and left anterior descending artery in 52.8%, and 30.3% of lesions were Medina 1,1,1. At a mean follow-up time of 27.0 ± 13.5 months, the survival free from MACE was 91.8%. Survival free from MACE was similar in patients grouped according to different bifurcated lesion complexity. On the contrary, patients receiving a single stent had better survival free from MACE as compared with those with double stent (P = 0.005). At multivariable analysis, double stenting (but not bifurcated lesion complexity) was found to be a significant predictor of MACE (hazard ratio, 2.52; 95% confidence interval, 1.28-4.94; P = 0.007). Of note, patients receiving the second stent as a bail-out had worse survival free from MACE compared with those who received it as a planned technique (P = 0.045). CONCLUSION: The treatment of patients with bifurcated lesions with second and third generation zotarolimus-eluting stents is associated with good long-term clinical outcomes. Clinical outcome seems to be independent of lesion complexity, but may be influenced by the stenting technique (single or double stenting as well as elective or bail-out double stenting). © 2015 Wiley Periodicals, Inc.

Quantification of manual thrombus removal in patients with acute coronary syndromes: a study exploiting serial frequency domain-optical coherence tomography.

AIMS: Thrombus aspiration is useful in improving myocardial reperfusion in comparison to conventional percutaneous coronary intervention in patients with acute myocardial infarction. Nonetheless, assessment of thrombus aspiration efficacy is lacking. Aim of this study was to quantify by frequency domain optical coherence tomography (OCT) the amount of thrombus removal in patients with acute coronary syndromes undergoing manual thrombus aspiration, correlating it with the actual size of the retrieved material. METHODS: Twenty-five consecutive patients with acute coronary syndrome were enrolled. OCT assessment of thrombotic lesions was performed before and after thrombus aspiration and repeated after stent deployment. OCT thrombus assessment was based on an established scoring technique. The aspirated material was analyzed by histology, and its planimetry was correlated with OCT-derived thrombus removal. RESULTS: The percentage of thrombus removal [(prethrombus aspiration minus post-thrombus aspiration)/(prethrombus aspiration × 100)] was 48.9; the delta measurement of the removed thrombus calculated by OCT correlated well with the planimetry-measured aspirated material (r = 0.56, P < 0.01). CONCLUSION: The present study showed the following: the thrombus score derived by OCT measurements correlated reasonably well with the planimetry measure of surface area of the actual aspirated material; after thrombus aspiration a large amount of residual thrombus can be appreciated at the target lesion site; and tissue components such as cholesterol debris and inflammatory cells can often be retrieved during thrombus aspiration.

Association between proximal stent edge positioning on atherosclerotic plaques containing lipid pools and postprocedural myocardial infarction (from the CLI-POOL Study).

Postprocedural myocardial infarction is an ominous complication of percutaneous coronary intervention (PCI). Despite several patient, lesion, and procedural factors that may affect its occurrence and severity, it is unclear if implanting a stent edge on a coronary lipid pool, as appraised by optical coherence tomography (OCT), adversely affects outcomes. The aim of this study was to assess the association between postprocedural myocardial infarction and the implantation of a stent edge on a lipid pool, as assessed by OCT. A database was screened for patients without ongoing myocardial infarctions; who underwent PCI with stenting for single, native, de novo lesions; without periprocedural side-branch occlusion or compromise; who underwent post-PCI OCT; and had postprocedural myocardial infarctions. These subjects were matched 1:1 with patients with similar features but without postprocedural myocardial infarctions. Plaque characterization with OCT was performed using established criteria. Specifically, lipid pools within stent edges were quantified by computing the number of involved quadrants and the degree of lipid arc on cross-sectional images. A total of 30 patients were included (15 with postprocedural myocardial infarctions and 15 controls without infarctions). Whereas no patient or control subject had lipid pools in correspondence to distal stent edges, landing of proximal stent edges on lipid pools was significantly more frequent in patients than in controls (10 [66%] vs 2 [13%], p = 0.009), Moreover, patients with postprocedural myocardial infarctions had more extensive lipid pools at proximal stent edges than those without postprocedural myocardial infarctions. Accordingly, lipid pool arc at proximal stent edge was significantly associated with peak post-PCI creatine kinase-MB/upper limit of normal ratio (Spearman's ρ = 0.49, p = 0.006). In conclusion, incomplete stent coverage of coronary lipid pools appears to be associated with an increased risk for postprocedural myocardial infarction in patients who undergo PCI.

Angiography alone versus angiography plus optical coherence tomography to guide decision-making during percutaneous coronary intervention: the Centro per la Lotta contro l'Infarto-Optimisation of Percutaneous Coronary Intervention (CLI-OPCI) study.

AIMS: Angiographic guidance for percutaneous coronary intervention (PCI) has substantial limitations. The superior spatial resolution of optical coherence tomography (OCT) could translate into meaningful clinical benefits. We aimed to compare angiographic guidance alone versus angiographic plus OCT guidance for PCI. METHODS AND RESULTS: Patients undergoing PCI with angiographic plus OCT guidance (OCT group) were compared with matched patients undergoing PCI with angiographic only guidance (Angio group) within 30 days. The primary endpoint was the one-year rate of cardiac death or myocardial infarction (MI). A total of 670 patients were included, 335 in the OCT group and 335 in the Angio group. OCT disclosed adverse features requiring further interventions in 34.7%. Unadjusted analyses showed that the OCT group had a significantly lower one-year risk of cardiac death (1.2% vs. 4.5%, p=0.010), cardiac death or MI (6.6% vs. 13.0%, p=0.006), and the composite of cardiac death, MI, or repeat revascularisation (9.6% vs. 14.8%, p=0.044). Angiographic plus OCT guidance was associated with a significantly lower risk of cardiac death or MI even at extensive multivariable analysis adjusting for baseline and procedural differences between the groups (OR=0.49 [0.25-0.96], p=0.037) and at propensity-score adjusted analyses. CONCLUSIONS: This observational study, the first ever formally to appraise OCT guidance for PCI decision-making, suggests that the use of OCT can improve clinical outcomes of patients undergoing PCI.

Percutaneous coronary intervention of unprotected left main coronary artery disease as culprit lesion in patients with acute myocardial infarction.

OBJECTIVES: This study sought to evaluate short- and long-term outcomes of patients undergoing emergency percutaneous coronary intervention (PCI) for acute myocardial infarction due to a culprit lesion in an unprotected left main coronary artery. METHODS: In this retrospective, 2-center, international observational study, 5,261 patients were admitted between February 2005 and December 2008 with acute myocardial infarction and treated with PCI; of these, 1,277 were ST-segment elevation myocardial infarction and 3,984 non-ST-segment elevation myocardial infarction. We identified 48 patients among this cohort who underwent emergency PCI to an unprotected left main coronary artery culprit lesion. RESULTS: Mean age was 70 ± 12.5 years, and 45% of the patients presented with ST-segment elevation myocardial infarction or new left bundle branch block. Cardiogenic shock was present in 45%, and distal left main coronary artery disease was present in 71% of patients. Angiographic procedural success was achieved in 92% of patients. Overall in-hospital mortality was 21%, due in all cases to refractory, multiorgan failure. Twenty-five percent experienced major adverse cardiac events, defined as death, myocardial infarction, stent thrombosis, and target vessel revascularization. In patients presenting in cardiogenic shock, in-hospital mortality was 32%. At 1-year follow-up, in-hospital survivors had a mortality rate of 10.5%, whereas 18.4% experienced subsequent major adverse cardiac events. Long-term prognosis was excellent in hospital survivors with a 1-year survival rate of 89.5%. CONCLUSIONS: Patients with acute myocardial infarction and thrombosis of the unprotected left main coronary artery are a high-risk subgroup with a substantial mortality, particularly if they present in cardiogenic shock. We demonstrate that in these patients, PCI is a feasible treatment option associated with reasonably good outcomes. Long-term prognosis is excellent in hospital survivors with an 89.5% survival rate at 1 year.

Safety and feasibility of frequency domain optical coherence tomography to guide decision making in percutaneous coronary intervention.

AIMS: The purpose of this single centre registry is to assess safety and feasibility of the frequency domain optical coherence tomography (FD-OCT) system during coronary interventions. METHODS AND RESULTS: Ninety patients with unstable or stable coronary artery disease were included in this study. OCT imaging was performed in a first group of 40 patients (group 1), to evaluate ambiguous/intermediate lesions (24 patients in group 1 had OCT also done post-PCI, for assessment of stent deployment); and in a second group of 50 patients (group 2), to address the adequacy of stent deployment. Therefore, 74 patients underwent FD-OCT after stent implantation. A complex-lesion population was studied (B2 type lesion=72.2% and C type lesion=20.3%). The mean time of a FD-OCT pull-back (from the set up to the completion of the pull back) was 2.1 min and in all but one (99.1%) the procedure was successful. No patients experienced major complications in terms of death, myocardial infarction, emergency revascularisation, embolisation, life-threatening arrhythmia, coronary dissection, prolonged and severe vessel spasm and contrast induced nephropathy. In the ambiguous lesion group, 60% of patients were treated with PCI, whilst in the others, PCI were deferred. In total, 113 deployed stents (33,6% chromium cobalt stent, 66,4% drug eluting stent) were imaged with OCT. OCT findings led to additional interventions in 24 out of 74 patients (32%): 15 had further balloon inflations, nine had additional stent deployment whilst two had both treatments. At clinical follow-up, (4.6 ± 3.,2 months), there were no death, acute myocardial infarctions and cases of stent thrombosis, whilst two patients underwent revascularisation for recurrence of angina. CONCLUSIONS: The present registry shows that FD-OCT is a feasible and safe technique for guidance of coronary interventions. Randomised studies will confirm whether the use of FD-OCT will improve the clinical outcome.

Angiographic predictors of recurrent stent thrombosis (from the Outcome of PCI for stent-ThrombosIs MultIcentre STudy [OPTIMIST]).

Stent thrombosis is a catastrophic occurrence burdened by a high mortality rate and a tendency to recur. We sought to evaluate the angiographic risk factors for recurrent stent thrombosis (rST) in a subpopulation of 91 Outcome of PCI for stent-ThrombosIs Multicenter STudy (OPTIMIST) patients who underwent quantitative angiographic evaluation by an independent core laboratory. The Academic Research Consortium criteria were used for rST adjudication. A multivariate Cox proportional hazards model was applied to estimate the hazard ratios and the corresponding 95% confidence intervals for the occurrence of Academic Research Consortium-defined, definite rST (primary end point), definite or probable rST (secondary end point), and definite or probable or possible rST (secondary end point). A total of 8 definite rST events occurred during a median follow-up of 244 days (range 165 to 396), of which 5 were early and 3 were late. In the multivariate model, a residual thrombus score of > or =3 (hazard ratio 6.5, 95% confidence interval 1.4 to 30.7, p = 0.017) and a larger postprocedural reference vessel diameter (hazard ratio 4.5, 95% confidence interval 1.5 to 13.3, p = 0.006) were significantly associated with the primary end point. When the same model was applied to the 15 definite and probable rST events, only a residual thrombus score of > or =3 (hazard ratio 7.8, 95% confidence interval 2.5 to 24.5, p <0.001) was significantly associated with rST. Finally, when possible rST events were included (18 patients), a residual thrombus score of > or =3 remained associated with the dependent variable (hazard ratio 6.1, 95% confidence interval 2.0 to 18.2, p = 0.001), along with a larger postprocedural reference vessel diameter. In conclusion, when performing percutaneous coronary intervention for stent thrombosis, the residual thrombus burden and larger reference vessel were potent risk factors for rST.

Angiographic and clinical outcome of invasively managed patients with thrombosed coronary bare metal or drug-eluting stents: the OPTIMIST study.

AIMS: Stent thrombosis (ST) is a major complication of percutaneous coronary interventions (PCIs). An invasive management by re-PCI is the commonly adopted treatment for ST, but data on outcome are limited. METHODS AND RESULTS: We performed a 2-year multicentre registry enrolling consecutive patients with angiographically confirmed ST undergoing PCI. The primary angiographic endpoint was optimal angiographic reperfusion (TIMI 3 + blush grade 2 or 3). The primary clinical endpoints were death and major adverse coronary and cerebrovascular events (MACCEs) at 6 months. A total of 110 patients underwent 117 urgent PCI during the study. Patients with drug-eluting stent (DES) thrombosis, compared with those with bare metal stent (BMS) thrombosis, exhibited a higher rate of late or very late presentation and of anti-platelet therapy withdrawal. Optimal angiographic reperfusion was obtained in 64% of the patients. Death and MACCE rates at 6 months were 17 and 30%, respectively. Clinical outcome was similar for BMS and DES thrombosis. Very late ST, implantation of stent during PCI for ST, and failure to achieve optimal angiographic reperfusion were the independent predictors of 6-month mortality. CONCLUSION: DES and BMS thromboses have different clinical features, but a similar poor outcome. Indeed, PCI for ST is associated with a low rate of reperfusion and to a high rate of death and MACCE, calling for action in order to prevent its occurrence and to improve its management.

The Outcome of PCI for stent-ThrombosIs MultIcentre Study (OPTIMIST): rationale and design of a multicenter registry.

BACKGROUND: Stent thrombosis (ST) is a recognized complication limiting the clinical efficacy of percutaneous coronary interventions (PCI). Because of the increasing number of stent-based PCI, the absolute number of patients experiencing ST is expected to expand. Re-PCI is the commonly adopted treatment for patients with ST; however, the prognostic variables as well as the angiographic and clinical results have not been systematically assessed. Moreover, the possible benefit associated with the use of adjunctive devices (AD) with theoretical antiembolic property has not been systematically analyzed in this high-risk population. METHODS: We present the design of a prospective and retrospective multicenter registry to assess the contemporary angiographic and clinical outcome of PCI in patients with ST. Moreover, we sought to assess if the use of thrombectomy or distal protection AD is associated with any improvement in the PCI's angiographic results. All patients with angiographically confirmed ST undergoing attempt of PCI in the enrolling centers during a fixed 2-year study period will enter the study. Clinical outcome during hospitalization, at 30 days and 6 months will be assessed. Percutaneous coronary intervention with or without AD will be performed according to physician's discretion. All PCI cine-film will undergo blind core laboratory analysis to assess a series of key angiographic data (TIMI flow, TIMI frame count, thrombus score, myocardial blush grade, distal embolization). CONCLUSIONS: The OPTIMIST study is designed to provide a detailed description of the angiographic and clinical outcome achieved in the real world with contemporary PCI for ST. Moreover, it will provide observational data regarding the role of AD in this high-risk scenario.

The RESTART project: high-dose atorvastatin helps control RESTenosis AfteR sTenting procedures at high risk for restenosis. Results from a prospective study and a matched control group comparison.

AIMS: The long-term results of bare stenting in complex procedures are troubled by a high incidence of restenosis. The use of drug-eluting stents lead to excellent long-term angiographic results, but require, long-term antithrombotic treatment to prevent stent thrombosis. We evaluated the efficacy of high-dose atorvastatin as an adjuvant in limiting clinical and angiographic restenosis after bare stenting procedures which carry an high risk of restenosis. METHODS AND RESULTS: Between November 2003 and February 2004, 91 consecutive patients (with 152 target lesions) underwent successful interventional procedures with bare stents (158 stents; 1.7 stent/patient). The patients were included in the study in the presence of at least one of the following criteria: diabetes mellitus (14.6%); acute myocardial infarction (8.8%); lesion length >15 mm (27.5%); lesion in vessels with a reference diameter of <2.5 mm (24.2%); >2 treated lesions (58.2%); side-branch lesions (3.3%). All patients were started on atorvastatin (80 mg/day) on the day of the procedure, and continued receiving it for at least nine months.Six of the 91 patients (6.5%) experienced a clinical restenosis and underwent target lesion revascularisation; a further two underwent re-PTCA due to progressive atherosclerosis in untreated sites. Seventy-one patients (78.0%; 125 stents) were followed up with angiography after a mean 8.5 months (7-10 months): binary angiographic restenosis was observed in 18/71 patients (25.3%) (in-stent restenosis 21.1%; in-segment restenosis 4.2%), and 17/125 stents (13.6%).We matched 122 lesions (125 stents) from the present population with a reference group of 600 consecutive lesions treated at the Ospedale Maggiore della Carità in Novara during the same period of time, but without high-dose statin treatment: 88 lesions (94 stents) were successfully matched on the basis of the clinical and angiographic variables of diabetes, acute myocardial infarction, treated vessel, reference diameter and lesion length. The incidence of late loss was significantly lower in the atorvastatin group (p=0.027). CONCLUSIONS: The RESTART prospective study showed that the adjunct of atorvastatin 80 mg leads to excellent clinical and angiographic outcomes. These results were confirmed in a matched lesion comparison.

Use of abciximab prevents microcirculatory impairment in patients treated with coronary angioplasty for unstable angina: results of a prospective randomized study.

The use of abciximab during percutaneous coronary angioplasty (PTCA) in patients with unstable angina (UA) prevents the postintervention enzyme surge and improves clinical outcomes, possibly by improving microcirculatory function. The aim of this quantitative myocardial blush grade (MBG) study was to verify whether abciximab improves postintervention microcirculation in patients with UA. This prospective randomized open-label study involved 140 UA patients scheduled to undergo PTCA of the target coronary lesion: 140 patients were randomized to receive either abciximab during PTCA (group 1, 70 patients) or conventional treatment without GP IIb/IIIa inhibitor (group 2, 70 patients). The exclusion criteria included above normal CK-MB levels. MBG was calculated by means of quantitative software that evaluates video intensity in a given region of interest: assuming that greater peak video intensity reflects a larger myocardial blood volume, a perfusion scale of 1-6 points (poor to optimal) was devised. The groups were homogeneous in terms of their demographic, procedural, and angiographic characteristics. Stents were used in 98% of the patients in both groups. The MBG score significantly increased in group 1 from 3.04 +/- 2.17 to 3.71 +/- 2.02 (P = 0.045) and slightly decreased in group 2 from 3.13 +/- 2.07 to 2.93 +/- 2.03 (P = 0.42). Consequently, group 1 showed a significantly greater postintervention MBG score (3.71 +/- 2.02 vs. 2.93 +/- 2.03; P = 0.022) and had a significantly greater MBG score change (P = 0.025). The results of this randomized study show that the administration of abciximab prevents microcirculatory impairment in patients undergoing angioplasty for acute coronary syndromes.

Stenting of culprit lesions in unstable angina leads to a marked reduction in plaque burden: a major role of plaque embolization? A serial intravascular ultrasound study.

BACKGROUND: Intravascular ultrasound (IVUS) studies have shown that a mechanism of plaque compression/embolization contributes toward the poststenting increase in lumen area. The aim of this IVUS study was to compare the mechanisms of lumen enlargement after coronary stenting in 54 consecutive patients with unstable angina (UA) (group 1) and 56 with stable angina (group 2) to verify whether plaque embolization plays a major role in the former. METHODS AND RESULTS: Both groups underwent the IVUS assessment (speed, 0.5 mm/sec) before the intervention and after stent implantation. The lumen area, the external elastic membrane area, and the plaque+media area (PA) were measured at 0.5-mm intervals. PA reduction in the lesion site was significantly greater in group 1 (-2.50+/-1.97 versus -0.53+/-1.43 mm2, P<0.001). After stenting, 47% of the lumen area increase in group 1 was obtained by means of PA reduction, and 53% was attributable to external elastic membrane area increase; the corresponding figures in group 2 were 13% and 87% (P<0.05). Decrease in PA after stenting was the only significant predictor of the MB fraction of creatinine kinase (CK-MB) release in a multiple regression model (P=0.047). CONCLUSIONS: Serial volumetric IVUS assessment revealed in UA lesions a marked poststenting reduction in plaque volume, which is significantly greater than in stable angina and is associated with postprocedural CK-MB release. The decrease in PA during the procedure predicts CK-MB release in a multiple regression model. These findings suggest that stent deployment is often associated with plaque embolization in patients with UA.

Intravascular ultrasound and quantitative coronary angiography assessment of late in-stent restenosis: in vivo human correlation and methodological implications.

Quantitative coronary angiography (QCA) is routinely used for assessment of strategies aimed at reducing in-stent restenosis. Yet QCA enables only the measurement of luminal variation of stented segments and, unlike intravascular ultrasound (IVUS), provides only an indirect estimation of late in-stent neointimal formation, which has a key role in the process of in-stent restenosis. The aims of the present study were to correlate the IVUS measurement of in-stent intimal hyperplasia (IH) with QCA indexes of restenosis, to find out whether QCA is an adequate surrogate of IVUS, and, using either QCA and IVUS data, to define the sample sizes needed to demonstrate the effectiveness of strategies to reduce in-stent restenosis. The database of the European Imaging Laboratory was used to screen 154 stents implanted between 1997 and 2001 and studied by IVUS at 6 +/- 1 months of follow-up. All cases underwent serial QCA assessment (preintervention, postintervention, and follow-up). Only 131 cases with single stent implantation in native coronary arteries were included in the study. Stent restenosis, defined as percent diameter stenosis (DS) > 50%, was present at QCA in 69 out of 131 cases (53%). Linear regression analyses were performed to correlate the amount of IH, calculated by IVUS as the average of all cross-section areas (CSA; mean % IH CSA) and QCA indexes of restenosis (late loss and % DS). A positive significant correlation was found between IVUS mean % IH CSA and QCA % DS (r = 0.74; P < 0.0001) and between IVUS mean % IH CSA and QCA late loss (r = 0.72; P < 0.0001). Based on IVUS measurements of mean % IH CSA, a total sample size of 74 stents would be required in a two-arm comparison to have 0.80 power to detect at 0.05 significant level a 30% difference between two compared groups. Alternatively, adopting the QCA late loss, 230 stents would be required. QCA measurements of late in-stent restenosis are well correlated with IVUS calculation of in-stent neointimal formation. IVUS assessment of IH allows smaller sample sizes than QCA to document significant reductions of in-stent restenosis. Therefore, the use of IVUS should be encouraged in comparison studies aimed at revealing significant neointimal differences in small sample size populations.

Severity of coronary artery stenosis at preoperative angiography and midterm mammary graft status.

BACKGROUND: The purpose of this study was to evaluate the correlation between the midterm angiographic results of mammary artery grafts and the preoperative stenosis of the target vessel. METHODS: We analyzed preoperative and postoperative angiograms of 93 patients who underwent postoperative midterm (> or = 3 years) angiograms of an internal mammary artery (IMA) to left anterior descending artery graft for clinical or study purposes. Patients were divided into three groups on the basis of the percentage of the coronary artery stenosis at preoperative angiography: < 70%, 70% to 90%, and > 90% stenosis. RESULTS: Preoperative characteristics were similar in the three groups. The overall incidence of IMA occlusion was 19% in the entire population, without significant differences between groups (19% versus 29% versus 14%). The mean mammary artery diameter significantly increased in direct proportion to the severity of the coronary stenosis (2.0 +/- 0.2 mm in the < 70% versus 2.5 +/- 0.3 mm in the 70% to 90% and 2.7 +/- 0.4 mm in the > 90% series; p < 0.05). CONCLUSIONS: Chronic native competitive flow does not significantly affect midterm graft status but does influence mammary graft diameter.

Normal distribution of an intravascular ultrasound index of vessel remodeling.

BACKGROUND: As a consequence of plaque accumulation, coronary arteries may undergo both compensatory enlargement and paradoxical constriction. The aim of this study was to address the distribution of the different remodeling patterns in patients with obstructive coronary atherosclerosis. METHODS: Eighty-seven non-branching segments of native coronary arteries with de novo, focal, non-ostial lesions were imaged at intravascular ultrasound (IVUS). Images were acquired with a motorized pull-back at a speed of 0.5 mm/s. The cross-sectional area (CSA) circumscribed by the external elastic membrane (EEM), the plaque + media complex and the lumen area were measured at its narrowest site (CSA with the minimal lumen area) and in the reference segment (average of proximal and distal reference cross-sections, defined as the most normal looking sites). The IVUS index of vessel remodeling (VRI) was calculated using the following formula: (narrowest site EEM CSA--reference EEM CSA)/reference EEM CSA*100. The index was tested for normality using the Kolmogorov-Smirnov goodness-of-fit test. RESULTS: The frequency distribution of VRI was found to have a normal unimodal distribution (p = 0.60). VRI ranged from -60 to +164, with a mean of 9.3 +/- 28.0 and a median of 3.6. Frequency distribution of VRI slightly skewed towards right (skewness index 1.69). None of the analyzed clinical and morphological variables predicted the presence of compensatory enlargement as opposed to paradoxical constriction. CONCLUSIONS: The frequency distribution of the vascular remodeling of de novo coronary lesions is unimodal. Therefore, compensatory enlargement and paradoxical constriction represent the extremes of a continuous spectrum.