NETs detection and quantification in paraffin embedded samples using confocal microscopy.

Detection and quantification of Neutrophil Extracellular Traps (NETs) in tissue samples has become a topic of great interest to understand their pathological role in various diseases. We describe a semi-automatic method of visualization and quantification of NETs in paraffin-embedded intracoronary thrombus aspirate samples. This study is based on colocalization of myeloperoxidase (MPO) and citrullinated histone 3 (H3Cit) as hallmark of the presence of NETs. For the analysis we used the confocal immunofluorescence microscopy technology to quantify the number of fields and the total area (in µm2) containing NETs in each thrombus sample. This observer-independent quantification method could be a useful tool to standardize the study of NETs in paraffin-embedded tissues, enabling comparison of results among different laboratories.

Occupational eye lens doses in interventional cardiology. A multicentric study.

New European regulation regarding radiological protection of workers and more specifically the new occupational dose limit for the eye lens recently reduced to 20 mSv yr(-1) may affect interventional cardiologists. This paper presents a set of measurements of occupational doses performed in five interventional cardiology centres and then compared with the new dose limit. The measurement of occupational doses was performed over the apron at chest level using electronic dosemeters recording H p(10). In one of the centres, scatter dose at goggles was also measured with optically stimulated luminescence dosemeters calibrated in terms of H p(0.07). An average H p(10) over the apron of 46 µSv/procedure was measured for cardiologists. Lower doses were noted in other professionals like second cardiologists, nurses or anaesthetists. Procedures for valvular and other structural heart diseases involved the highest occupational doses, averaging over 100 µSv/procedure. Important differences in occupational doses among centres may be indicative of different radiation protection habits. The new occupational dose limit for the eye lens is likely to be exceeded by those among the interventionalists who do not use protection tools (ceiling suspended screen and/or goggles) even with standard workloads.

Comparison of sirolimus eluting stent with bioresorbable polymer to everolimus eluting stent with permanent polymer in bifurcation lesions: Results from CENTURY II trial.

OBJECTIVE: To demonstrate the safety and efficacy of a new sirolimus eluting stent with bioresorbable polymer, Ultimaster, (BP-SES) compared with everolimus-eluting, permanent polymer, Xience stent (PP-EES) in bifurcation lesions with respect to the freedom from Target Lesion Failure at 1-year. METHODS: Within 1,119 patients enrolled in the CENTURY II randomized controlled multicenter trial, 194 patients were treated for bifurcation lesions and randomized to either BP-SES (n = 95) or PP-EES (n = 99). The primary endpoint was freedom from target lesion failure (TLF) composite endpoint [cardiac death, MI not clearly attributable to a non-target vessel, and clinically driven target lesion revascularization (TLR)] at 1-year. RESULTS: Baseline patient demographic, angiographic, and stenting characteristics were similar in both study arms. A single stent technique with provisional or "cross over" stenting were the most widely used in both arms (93.2% BP-SES vs. 92.4% PP-EES). Freedom from TLF at 1-year was 94.7% for BP-SES and 91.9% for PP-EES (P for noninferiority 0.031). The rate of clinically driven target lesion revascularization (TLR) at 1-year was 3.2% for BP-SES and 3.0% for PP-EES (P = 0.95). There were no significant differences detected in any of the individual clinical endpoints or other secondary clinical endpoints between the study arms at 1-year follow up. CONCLUSIONS: The new bioresorbable polymer sirolimus-eluting stent showed safety and efficacy profiles similar to durable polymer everolimus-eluting in the treatment of patients with bifurcation lesions at 1-year follow up. © 2015 Wiley Periodicals, Inc.

The TITAN-AMI multicenter registry evaluating the usage of Titan2 stent in patients with ST segment elevation myocardial infarction. Final result at 12-month follow-up.

AIM: Primary percutaneous coronary intervention with stent implantation is the recommended treatment for patients with ST elevation myocardial infarction (STEMI). Data from randomised trials showed good performance by a titanium-nitric-oxide coated stent in this context. The aim of this study was to confirm these data. METHODS: A multicentre registry was compiled in 23 hospitals in Spain in an all-comers population. We selected patients with STEMI from a global Titan AMI registry that included patients with acute coronary syndrome. Primary endpoint was the composite of cardiac death, non-fatal myocardial infarction, stent thrombosis and target lesion revascularisation, at 12-month follow-up. RESULTS: The study included 893 patients with STEMI. We included all possibilities for PCI: 86.6% primary, 5% facilitated after successful fibrinolysis and 8.4% rescue PCI after failed fibrinolysis. The primary endpoint was reached in 8.4% of the patients: cardiac death 2.7%, reinfarction 3.4%, target lesion revascularisation 3.5% and definite or probable stent thrombosis 2.8%. The majority of stent thromboses presented in the first 30 days after PCI. CONCLUSION: A bioactive stent (titanium-nitric-oxide coated stent) is a possible alternative for the treatment of patients with STEMI. One-year follow-up showed better results than those presented by a regular bare-metal stent or first-generation drug-eluting stent in terms of stent thrombosis.

Safety of intravenous ivabradine in acute ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention: a randomized, placebo-controlled, double-blind, pilot study.

AIMS: Rapid heart rate lowering may be attractive in acute ST-segment elevation myocardial infarction (STEMI). Accordingly we studied the effect of intravenous ivabradine on heart rate in this setting. METHODS AND RESULTS: This was a multicenter randomized double-blind placebo-controlled trial: patients aged 40-80 years were randomized after successful primary percutaneous coronary intervention (PCI) performed within 6 h of STEMI symptom onset. Patients were in sinus rhythm and with heart rate >80 bpm and systolic blood pressure >90 mm Hg. They were randomly assigned (2:1 ratio) to intravenous ivabradine (n=82) (5 mg bolus over 30 s, followed by 5 mg infusion over 8 h) or matching placebo (n=42). The primary outcome measure was heart rate and blood pressure. In both groups, heart rate was reduced over 8 h, with a faster and more marked decrease on ivabradine than placebo (22.2 ± 1.3 vs 8.9 ± 1.8 bpm, p<0.0001). After treatment discontinuation, heart rate was similar in both groups. Throughout the study, there was no difference in blood pressure between groups. There was no difference in cardiac biomarkers (creatine kinase (CK-MB), troponin T and troponin I). On echocardiography performed at baseline and post treatment (median 1.16 days), final left ventricular volumes were lower in the ivabradine group both for left ventricular end-diastolic volume (LVEDV) (87.1 ± 28.2 vs 117.8 ± 21.4 ml, p=0.01) and left ventricular end-systolic volume (LVESV) (42.5 ± 19.0 versus 59.1 ± 11.3 ml, p=0.03) without differences in volume change or left ventricular ejection fraction. CONCLUSION: This pilot study shows that intravenous ivabradine may be used safely to slow the heart rate in STEMI. Further studies are needed to characterize its effect on infarct size, left ventricular function and clinical outcomes in this population.

A national programme for patient and staff dose monitoring in interventional cardiology.

A national programme on patient and staff dose evaluation in interventional cardiology made in cooperation with the haemodynamic section of the Spanish Society of Cardiology has recently been launched. Its aim is to propose a set of national diagnostic reference levels (DRLs) for patients as recommended by the International Commission on Radiological Protection and to initiate several optimisation actions to improve radiological protection of both patients and staff. Six hospitals have joined the programme and accepted to submit their data to a central database. First to be acquired were the quality control data of the X-ray systems and radiation doses of patients and professionals. The results from 9 X-ray systems, 1467 procedures and staff doses from 43 professionals were gathered. Provisional DRLs resulted in 44 Gy cm(2) for coronary angiography and 78 Gy cm(2) for interventions. The X-ray systems varied up to a factor of 5 for dose rates in reference conditions. Staff doses showed that 50 % of interventional cardiologists do not use their personal dosemeters correctly.

Study of the evolution of the shear stress on the restenosis after coronary angioplasty.

In this article, we analyze the influence of fluid dynamics variables on the development of obstructive coronary artery disease in the medium term after percutaneous coronary intervention with stent implantation. We have analyzed a group of seven patients and the study is focused on the mid-right coronary artery. In these patients we have studied the relationship between wall shear stress and arterial wall thickness both immediately after stent implantation and six months later. The realistic three-dimensional (3D) reconstruction of the arteries is performed with the data obtained with intravascular ultrasound (IVUS) and angiography. The commercial code Fluent is used to solve the Navier-Stokes equations. Special attention is paid to the shear stress on the wall arteries and the corresponding thickness. The results show that there is a negative correlation for most of the cases between the wall shear stress and increase in wall thickness. A model is proposed to study the instability at the wall, and qualitative agreement is found.

Skin radiation injuries in patients following repeated coronary angioplasty procedures.

This study investigates the incidence of skin injuries and retrospectively estimates skin doses in a sample of patients who had multiple coronary angiographies and who underwent more than four percutaneous transluminal coronary angioplasties (PTCAs), performed primarily by the same team of cardiologists in a university hospital. A database of 7824 PTCAs performed during the last 14 years was analysed. Patients were selected and reviewed by a cardiologist and two radiotherapists with experience in radiation-induced skin injuries. A retrospective analysis of skin doses was performed using data from the patients' files and from the quality assurance (QA) programme of the hospital, which includes periodic patient dose measurements. 14 patients were included in the study. Each patient had undergone between 4 and 14 coronary angiographies and between 5 and 10 PTCAs, performed over a period of 2-10 years. The estimated mean dose-area product per procedure was 46 Gy cm(2) for coronary angiography and 82 Gy cm(2) for PTCA. Mean values of maximum skin dose per procedure were 217 mGy for the diagnostic studies and 391 mGy for the PTCAs. Only a slight radiation skin injury was clinically demonstrated in one patient with a history of 10 coronary angiographies and 10 PTCAs (estimated maximum skin dose 9.5 Gy). Another patient who underwent 14 coronary angiographies and 10 PTCAs (estimated maximum skin dose 7.3 Gy) showed a slight telangiectasia and discrete pigmentation. Another patient with a cutaneous lupus erythematosus showed pigmentation in the area of the radiation field following seven coronary angiographies and six PTCAs (estimated maximum skin dose 5.6 Gy), as expected bearing in mind that skin tolerance to high doses may be altered for patients with this pathology. Each of the remaining 11 patients with no skin injuries had undergone between 5 and 7 PTCAs and between 5 and 14 additional angiographies. None of the 14 patients reported acute skin injuries and no necrosis or radiodermatitis was observed.

[Safety and efficacy of an early deambulation protocol after PTCA with an angio-seal device]. / Seguridad y eficacia de un protocolo de deambulación precoz, con dispositivo de hemostasia Angio-seal, tras angioplastia coronaria.

INTRODUCTION: In order to assess the efficacy and safety of an early deambulation (1-2 h) protocol after coronary angioplasty using the Angio-seal collagen plug, we analyzed a consecutive series of patients treated with this device versus a reference group treated with mechanical compression. PATIENTS AND METHODS: Two hundred and seven coronary angioplasty patients were included from February to August 2000. Ninety-eight were treated with mechanical compression and one hundred and nine with the Angio-seal collagen plug. All patients were followed at discharge and fifteen days after surgery. RESULTS: Eighty percent of the patients receiving the Angio-seal device achieved immediate hemostasis (< 1 min). In patients with mechanical compression hemostasis was achieved within 30 min in 68.3%, whereas 25.5% of patients required more than 40 min. First deambulation in the Angio-seal group was achieved within 2 h in 94.5% of the patients. The incidence of major complications was low in both groups (1 case in the Angio-seal group and 2 in the C-clamp group) without statistically significant differences. The Angio-seal group showed a lower incidence of overall vascular complications as compared to the C-clamp group (4.6% vs. 14.3%; p = 0.02). CONCLUSION: Following our protocol, an early deambulation strategy after coronary angioplasty with the use of the Angio-seal collagen plug was feasible, safe and efficacious.

Quality criteria for cardiac images in diagnostic and interventional cardiology.

The quality of cardiac imaging plays a pivotal role in clinical decision-making and depends mainly on the technical performance of the imaging system and on angiographic technique. The Italian Society of Invasive Cardiology and The Italian Society of Physics in Medicine have set quality criteria giving precise guidelines regarding how an angiogram should appear provided that good equipment and correct angiographic technique are used. The criteria have been reviewed by the European Concerted Action DIMOND Cardiology group and are reported here to provide a reference standard for images for the most common procedures in daily practice.

A method based on DIMOND quality criteria to evaluate imaging in diagnostic and interventional cardiology.

Image quality criteria (IQC) for cine-angiography were recently settled. The aim of this study was to test whether these criteria allow a measurement of the quality of cine-angiograms. A questionnaire was derived from IQC where a binary response was required regarding the degree of visibility of anatomic or pathologic structures. Scores were given on a ranking scale. Two quality scores were defined (total score and minimum score) and standard deviation (SD) was assumed to be an indicator of the method's reproducibility. Data of the total score are presented for the first nine angiograms. Six experts obtained thirty-nine readings. The total scores ranged between 83 and 99% (SD 0.8-18.7%); 89% of the readings were within 4% of SD. This preliminary experience indicates that quality criteria can be translated into a scoring system that yields reproducible data in most instances. The analysis of the remaining angiograms will help in understanding how to improve these results.

[Registry of the Activity of the Section of Hemodynamics and Interventional Cardiology of the Spanish Society of Cardiology for the year 2000]. / Registro de Actividad de la Sección de Hemodinámica y Cardiología Intervencionista de la Sociedad Española de Cardiología del año 2000.

The results of the Registry of the Working Group on Hemodynamics and Interventional Cardiology of the Spanish Society of Cardiology for 2000 are presented. Date came from 100 centers representing all the cardiac catheterization laboratories in Spain; 93 centers performed mainly adult catheterization and 7 carried out only pediatric procedures. In 2000, 88,339 diagnostic catheterization procedures were performed (73,382 coronary angiograms), representing a total increase of 12.5% over 1999. The population-adjusted rate was 1,825 coronary angiograms per 106 inhabitants. With a total of 26,993 procedures and a rate of coronary interventions per 106 inhabitants of 671, coronary intervention increased by 17% over figures for 1999. Coronary stents were the devices used most often, with 29,504 implanted in 2000; stenting accounted for 77.2% of procedures, a 30.5% increase over 1999. The increase in direct stenting without predilatation was noteworthy. Direct stenting was done in 8,778 procedures (38.9% of the total), an increase of 131% compared to 1999. IIb-IIIa glycoprotein were used in 4,700 coronary interventions (17%). Angioplasty, performed in 3,128 cases of acute myocardial infarction, accounted for 11.6% of coronary interventions 33.5% more than in 1999. A decrease of 6.5% in valvuloplastics occurred, attributable to the performance of fewer mitral valve repairs (493 vs 525 in 2000 and 1999, respectively). Pediatric procedures increased by 20.5%, from 678 to 817 cases. In conclusion, we would like to underline the high rate of reporting by laboratories, through which the Registry has been able to compile data that are highly representative of the hemodynamic activity in Spain.

[Aspiration of large intracoronary thrombus after apparently successful angioplasty. Therapeutic implications]. / Aspiración de gran trombo intracoronario tras angioplastia aparentemente con éxito. Implicaciones terapéuticas.

We present a case in which, after performing an optimal angioplasty after an acute myocardial infarction with intracoronary thrombus, normal coronary flow was not achieved. After aspirating through the guiding catheter we obtained a large thrombus that the histopathologic study confirmed as a recent thrombus and, subsequently, normal flow was reestablished. The procedure was completed with a successful intracoronary stent implantation, with an uneventful clinical course. The therapeutic and diagnostic implications of this case are discussed.

[The capacity of the rest-dobutamine gated SPECT protocol to predict contractile recovery after revascularization of myocardial dysinergic areas]. / Capacidad del protocolo de gated-SPECT reposo/dobutamina para predecir la recuperación contráctil posrevascularización de áreas miocárdicas disinérgicas.

INTRODUCTION AND AIM: Gated-SPECT is a promising method to analyze myocardial viability. We have assessed the accuracy of a new protocol of rest/Dobutamine gated-SPECT, based on the evaluation of contractile reserve induced by 10 microg/kg/min of Dobutamine, to predict contractile recovery after revascularization of dysinergic myocardial territories. PATIENTS AND METHODS: In a group of 36 patients submitted to percutaneous revascularization, we selected 40 vascular territories (21 left descending artery, 19 right coronary-circumflex) with severely depressed contractility (contrast ventriculography, center line method). Follow up evaluation at 6 months showed the absence of angiographic restenosis and control contrast ventriculography assessed the contractile changes of the selected territories, considering those with contractile restoration as viable. Before revascularization, rest/Dobutamine gated-SPECT study was applied and viability was defined as the presence of contractile reserve (positive or improvement [n = 21] and negative or impairment [n = 7]) with non viability being the absence of contractile reserve (n = 12). We analyzed the evolution of the ejection fraction in a group of 27 patients with impaired ventricular function and complete revascularization. RESULTS: Gated-SPECT showed a sensitivity of 0.96 (95% CI 0.78-0.99) and a specificity of 0.78 (95% CI 0.48-0.94) in the diagnosis of viability. The ejection fraction (median [interquartile range]) increased after revascularization: 0.42 (0.15) vs 0.55 (0.22), Z = -3.9; p < 0. 001. The diagnosis of viability by gated-SPECT (p < 0.001) and the extent of severely depressed myocardium (p = 0.04) independently predicted the increase of the ejection fraction after revascularization. CONCLUSIONS: The analysis of contractile reserve by rest/Dobutamine gated-SPECT is adequate to diagnose viability in territories with severely depressed contractility and independently predicts the increase of ejection fraction after revascularization.

Carvedilol for prevention of restenosis after directional coronary atherectomy : final results of the European carvedilol atherectomy restenosis (EUROCARE) trial.

BACKGROUND: In addition to its known properties as a competitive, nonselective beta and alpha-1 receptor blocker, carvedilol directly inhibits vascular myocyte migration and proliferation and exerts antioxidant effects that are considerably greater than those of vitamin E or probucol. This provides the basis for an evaluation of carvedilol for the prevention of coronary restenosis. METHODS AND RESULTS: In a prospective, double-blind, randomized, placebo-controlled trial, 25 mg of carvedilol was given twice daily, starting 24 hours before scheduled directional coronary atherectomy and continuing for 5 months after a successful procedure. The primary end point was the minimal luminal diameter as determined during follow-up angiography 26+/-2 weeks after the procedure. Of 406 randomized patients, 377 underwent attempted atherectomy, and in 324 (88.9%), a

Propensity and mechanisms of restenosis in different coronary stent designs: complementary value of the analysis of the luminal gain-loss relationship.

OBJECTIVES: This study sought to investigate the influence of stent design on the long-term angiographic outcome. BACKGROUND: The proportional relationship between vessel injury and late luminal loss in percutaneous revascularization should be best appreciated in coronary stenting, where recoil and shrinkage are theoretically minimal. It is unclear whether all stent designs can counterbalance this reactive loss by achieving a large initial luminal gain (bigger is better). METHODS: In 523 lesions successfully stented, the long-term angiographic results of slotted-tube (n = 331), coil (n = 85), multicellular (n = 70) and self-expandable mesh (n = 37) stent designs were compared using the angiographic gain-loss relationship (GLR). RESULTS: Restenosis rate was 10% for multicellular, 20% for slotted-tube, 46% for coil and 49% for self-expandable designs (p = 0.001). At a difference with other designs, no significant GLR was found in coil stents, suggesting additional mechanisms of luminal loss (i.e., plaque protrusion, stent compression) to neointimal proliferation. Significant differences in late loss between stents were found within each quartile of luminal gain, suggesting a specific role of design in luminal loss. Multivariate analysis identified use of coil and self-expandable stents, vessel size, minimal luminal diameter preintervention, luminal gain and stent length as variables with independent predictive value for several indices of angiographic long-term outcome. CONCLUSIONS: The analysis of GLR: 1) demonstrates that stent design influences late luminal loss; 2) challenges the applicability of the widely accepted "bigger is better" approach to all stent designs; and 3) appears as a valuable tool in assessing long-term stent performance.

Long-term angiographic results of stenting in chronic total occlusions: influence of stent design and vessel size.

BACKGROUND: Although coronary stenting has decreased the high restenosis rate associated with percutaneous transluminal coronary angioplasty of chronic total occlusions (CTOs), the results are still less satisfactory than those found in nonoccluded lesions, at least as reported with the Palmaz-Schatz stent. The present work compares the restenosis rate of other stent designs with that of the Palmaz-Schatz stent. METHODS: We studied the long-term angiographic outcome of 120 CTOs successfully recanalized with balloon-expandable stents and without concomitant debulking techniques. Angiographic follow-up and full quantitative coronary angiography analysis was prospectively performed in all patients. Three different stent designs were compared: Palmaz-Schatz (n = 47), coil (n = 24), and multicellular (n = 49). Particular attention was paid to their performance in vessels of 3 mm or less and greater than 3 mm in diameter. Restenosis was defined as a 50% or greater diameter stenosis at follow-up. RESULTS: Multicellular stents were implanted more frequently in the left anterior descending artery and in patients with multivessel disease. No other significant differences in clinical or angiographic baseline characteristics, including vessel size, were noted between groups. At follow-up, multicellular stents presented a lower restenosis rate (22% vs 36% and 58% in the Palmaz-Schatz and coil stent groups, respectively; P =.01 ) and larger minimal luminal diameters (1.92 +/- 0.85 mm vs 1.73 +/- 0.98 and 1.38 +/- 0.83 mm in the Palmaz-Schatz and coil stent groups, respectively; P = 0.0). The superiority of the multicellular stent design resulted from a lower restenosis rate in vessels of 3.0 mm or less in diameter (20% vs 47% and 79% in the Palmaz-Schatz and coil stent groups, respectively; P =.006). CONCLUSIONS: These results suggest that the restenosis rate after stent recanalization of CTOs is influenced by both stent design and vessel size and may indicate a superiority of multicellular over Palmaz-Schatz and coil stent designs for this purpose.

Results (>6 months) of stenting of >1 major coronary artery in multivessel coronary artery disease.

Multivessel percutaneous transluminal coronary angioplasty (PTCA) is associated with a high requirement for further revascularization procedures. Although stenting can reduce restenosis and clinical events after 1-vessel intervention, little information is available after multivessel coronary stenting. We followed up 136 patients (9% of 1,481 undergoing stenting in our center) who had had stent implantation in at least 2 different major native coronary arteries and were followed-up for >6 months. Each patient had received a mean of 2.3 +/- 0.6 stents (1.13 +/- 0.4 stents per lesion) and procedural success was 95%. In-hospital complications included 1 death, 1 Q-wave infarction, 5 non-Q-wave myocardial infarctions, and 1 repeat PTCA. After a mean of 18 +/- 13 months, 7 patients died (3 of heart failure, 4 of noncardiac causes), 2 required coronary bypass surgery, 1 had a myocardial infarction, 13 target vessel repeat PTCA, and 4 non-target vessel PTCA. Survival free of major cardiac events was 75% at 3 years. A history of heart failure, dilation of a restenotic lesion, and 3-vessel dilation were independent negative predictors of event-free survival. Angiographic follow-up was available in 86 patients: 56 (65%) were restenosis free, 23 (27%) had 1-vessel restenosis, and 6 (7%) had 2-vessel and 1 patient 3-vessel restenosis. Restenosis per vessel was 23% (41 of 177). Reference diameter, past-PTCA minimal luminal diameter, and length of the stent were independent predictors of restenosis. We conclude that multivessel stenting provides good midterm results in selected patients with multivessel coronary artery disease. Midterm events are less frequent than previously reported after balloon PTCA.

Initial results and long-term clinical and angiographic implications of coronary stenting in elderly patients.

Results of 378 consecutive elderly patients (> or = 65 years) undergoing coronary stenting were compared with those of 601 younger patients. Although the restenosis rate was similar in the 2 groups, age > or = 65 years was an independent predictor of in-hospital mortality (relative risk 5.4, 95% confidence interval 1.2 to 20.1) and follow-up mortality (relative risk 2.8, 95% confidence interval 1.3 to 6.1).

Value of intravascular ultrasound in the assessment of coronary pseudostenosis during coronary interventions.

Coronary pseudostenosis (PS) are increasingly visualized during coronary interventions. In many patients PS are readily recognized by a characteristic angiographic pattern, but in other cases the diagnosis remains difficult. The value of intravascular ultrasound (IVUS) in the study of PS remains unknown. In this study, IVUS was used to assess the morphologic appearance of the vessel wall in 10 consecutive patients showing images of PS during coronary interventions. Mean age of the group was 60+/-12 years and two patients were female. IVUS was performed with a motorized pullback system to assess lumen, plaque, and total vessel cross-sectional areas. Measurements were performed both at the site of PS and at the distal reference segment. PS were always located on angled coronary segments. In one patient no lumen narrowing was detected with IVUS at the site of PS. In the remaining nine patients, however, a very localized elliptic-shaped lumen narrowing was demonstrated. As compared with the distal reference segment, coronary lumen (6.3+/-2.2 vs. 12.7+/-4.8 mm2, P < 0.001) and total vessel area (11.9+/-3.3 vs. 16.1+/-6.1 mm2, P < 0.05) were smaller at the site of PS. Severe lumen asymmetry was also documented at this site. In addition, a characteristic image of a flattened, three-layered wall, overlying a hypoechogenic space, was visualized in five patients. This unique pattern was considered the correlate of a partial coronary intussusception. PS induced some resistance to the advancement of catheters in two patients and temporary flow impairment in two additional patients. However, in every case, the image of PS disappeared once the guidewire was removed. Thus, at sites with PS, IVUS allows ruling out severe atherosclerosis and coronary dissections. In addition, IVUS also provides important diagnostic clues, including the image of intussusception, for making the correct diagnosis of this benign entity.