A novel method for high-speed fabrication of large scale periodic arrays of nanoparticles (diameters 40-200 nm) is developed. This method is based on a combination of nanosphere lithography and laser-induced transfer. Fabricated spherical... more
A novel method for high-speed fabrication of large scale periodic arrays of nanoparticles (diameters 40-200 nm) is developed. This method is based on a combination of nanosphere lithography and laser-induced transfer. Fabricated spherical nanoparticles are partially embedded into a polymer substrate. They are arranged into a hexagonal array and can be used for sensing applications. An optical sensor with the sensitivity of 365 nm/RIU and the figure of merit of 21.5 in the visible spectral range is demonstrated.
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For years, the treatment of high-risk pulmonary embolism (PE) was based on two well-defined strategies: thrombolysis, whose benefits have been documented in randomized trials, and surgical embolectomy. However, mechanical reperfusion by... more
For years, the treatment of high-risk pulmonary embolism (PE) was based on two well-defined strategies: thrombolysis, whose benefits have been documented in randomized trials, and surgical embolectomy. However, mechanical reperfusion by percutaneous techniques is used in an increasing number of patients, and is a valid therapeutic option when there is a formal contraindication to thrombolysis, as rescue therapy when thrombolysis fails to improve hemodynamics, and/or when emergency surgical thrombectomy is unavailable or contraindicated. This article discusses the indications for the use of percutaneous techniques in PE, reports the initial experience of our center with the AngioJet® thrombectomy device (Possis Medical Inc, Minneapolis, MN, USA) and reviews the available evidence, the most recent recommendations and the main complications associated with this procedure.
... Rev Port Pneumol 2007; XIII (2): 239-254 Hipertensão Arterial Pulmonar Experiência do Centro Hospitalar de Vila Nova de Gaia Ana Oliveira, Daniela Ferreira, António Caiado, Susana Ferreira, Paula Ferreira, Lino Santos, Manuel... more
... Rev Port Pneumol 2007; XIII (2): 239-254 Hipertensão Arterial Pulmonar Experiência do Centro Hospitalar de Vila Nova de Gaia Ana Oliveira, Daniela Ferreira, António Caiado, Susana Ferreira, Paula Ferreira, Lino Santos, Manuel Gonçalves, Teresa Shiang ...
We report the case of a 77-year-old man with heart failure (NYHA class IV), angina (CCS class III) and multiple comorbidities. The evaluation showed severe aortic sten osis and left main coronary disease. Due to the very high... more
We report the case of a 77-year-old man with heart failure (NYHA class IV), angina (CCS class III) and multiple comorbidities. The evaluation showed severe aortic sten osis and left main coronary disease. Due to the very high perioperative risk, conventional surgery was denied. It was therefore decided to perform a combined percutaneous intervention. First, left main PCI was successfully performed. A few days later, a percutaneous aortic valve prosthesis was implanted via a femoral approach using the CoreValve ReValving system. Immediately after prosthesis implantation, the control angiogram showed severe paravalvular aortic regurgitation, which was corrected by implanting another percutaneous aortic prosthesis inside the first one (valve-in-valve procedure). During follow-up the patient experienced a remarkable improvement in hemodynamic and clinical status. We demonstrate that the combination of two different percutaneous interventions in severe aortic and coronary disease is feasible and can be a suitable alternative approach in high surgical risk patients.
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To compare the value of the myocardial perfusion imaging with 99Tc sestamibi (MIBI) with clinical data and stress EKG (SEKG) variables, in the detection of angiographic restenosis (AR: lesion > 50%), in a group of patients (pts) with... more
To compare the value of the myocardial perfusion imaging with 99Tc sestamibi (MIBI) with clinical data and stress EKG (SEKG) variables, in the detection of angiographic restenosis (AR: lesion > 50%), in a group of patients (pts) with single vessel disease (angiographic lesion above 70% in one epicardial artery), submitted to coronary angioplasty (PTCA) with stenting. Fifty-nine pts, followed prospectively, (49 males and 10 females aged 57 +/- 10) were submitted to 61 angioplasties, with dilatation of 59 vessels, and with stenting in 63 (1.07 stent/vessel). Clinical evaluation was performed in the first, third and sixth month, SEKG with MIBI in the fourth month and recatheterization for angiographic control in the sixth month. The pts were divided in two groups: R-positive angiographic restenosis (AR)--14 pts: NR--without AR--45 pts; the angiographic restenosis rate was 23.7%. The patients' history, cause of admission, procedure characteristics, medication at discharge, clinic...
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Assays of serum enzymes, such as aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and isoenzyme MB, are widely performed in the early phase of suspected ischemic myocardial injury. However, these enzymes... more
Assays of serum enzymes, such as aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and isoenzyme MB, are widely performed in the early phase of suspected ischemic myocardial injury. However, these enzymes are not restricted to cardiac muscle tissue and increases in their serum concentrations have been observed in non-cardiac conditions. The levels of CK, and especially those of the myocardial specific isoform (CK-MB), have served as essential components for clinical decision in emergency rooms for over 25 years. This standard diagnostic test is far from perfect in specificity and the time delay necessary for the detection of a rise in levels. The clinician needs specific and sensitive biological parameters that can be rapidly measured in serum immediately after ischemic damage. In the last years, several new serum markers of myocardial damage have been developed. Currently, an important place is reserved for some non-enzyme muscle constituents, such...
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Introdução: O encerramento percutâneo da comunicação interauricular tipo ostium secundum (CIA) e do foramen ovale persistente (FOP) é uma alternativa eficaz e segura à cirurgia. Para evitar o desconforto do ecocardiograma transesofágico... more
Introdução: O encerramento percutâneo da comunicação interauricular tipo ostium secundum (CIA) e do foramen ovale persistente (FOP) é uma alternativa eficaz e segura à cirurgia. Para evitar o desconforto do ecocardiograma transesofágico (ETE) e a necessidade de anestesia geral durante o procedimento, existe a possibilidade do controlo ecocardiográfico ser efectuado por ecocardiograma intracardíaco (EIC). Objectivo: Determinar a eficácia e segurança do encerramento percutâneo de CIA e FOP assistido por EIC. Métodos: De Abril de 2001 a Novembro de 2002, todos os encerramentos percutâneos de CIA e FOP foram efectuados com recurso ao EIC durante o procedimento, totalizando 31 doentes. A selecção dos doentes foi efectuada com base na clínica e ETE prévios. Todos os doentes foram tratados sem anestesia geral ou sedação. A técnica de oclusão percutânea foi assistida por EIC e fluoroscopia. Em todos os doentes foi utilizado dispositivo Amplatzer ® para encerramento de CIA e FOP, sendo o seu...
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The transcatheter closure of the atrial septal defect (ASD) has been proposed as an alternative to surgical therapy for the ostium secundum ASD. It is considered an effective and safe procedure, although rare but potentially fatal... more
The transcatheter closure of the atrial septal defect (ASD) has been proposed as an alternative to surgical therapy for the ostium secundum ASD. It is considered an effective and safe procedure, although rare but potentially fatal complications have been reported. The authors report a case of early migration of a device for transcatheter closure of an ASD to the right pulmonary artery.
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... Rev Port Pneumol 2007; XIII (2): 239-254 Hipertensão Arterial Pulmonar Experiência do Centro Hospitalar de Vila Nova de Gaia Ana Oliveira, Daniela Ferreira, António Caiado, Susana Ferreira, Paula Ferreira, Lino Santos, Manuel... more
... Rev Port Pneumol 2007; XIII (2): 239-254 Hipertensão Arterial Pulmonar Experiência do Centro Hospitalar de Vila Nova de Gaia Ana Oliveira, Daniela Ferreira, António Caiado, Susana Ferreira, Paula Ferreira, Lino Santos, Manuel Gonçalves, Teresa Shiang ...
The purpose of this study was to evaluate the in-hospital and follow-up prognostic value of cardiac troponin I in patients admitted in the Coronary Care Unit and discharged with the diagnosis of unstable angina. 118 patients were admitted... more
The purpose of this study was to evaluate the in-hospital and follow-up prognostic value of cardiac troponin I in patients admitted in the Coronary Care Unit and discharged with the diagnosis of unstable angina. 118 patients were admitted in the Coronary Care Unit, discharged with the diagnosis of unstable angina with a follow-up of 13.5 months. Cardiac Troponin I (cTnI) was measured on admission, 4 and 12 hours later. For the purposes of the study, we chose a cut-off value of 0.4 ng/mL as the minimal acceptable concentration of cTnI. The patients were divided in two groups: Group A (n = 82) if all measurements with cTnI < or = 0.4 ng/mL and Group B (n = 36) if any measurement with cTnI > 0.4 ng/mL. In both groups, multiple coronary events during hospitalisation and follow-up were evaluated: death; acute myocardial infarction; angina; hospitalisation; coronary surgery or angioplasty; and also the severity of coronary artery disease and the number of patients without coronary e...
Research Interests: Humans, Hospitalization, Female, Male, Follow-up studies, and 4 moreMiddle Aged, Myocardium, Prognosis, and Troponin I
A considerable number of patients present a single intermediate lesion (>40% and <70%) in one coronary artery on coronary angiography, with no clear evidence that the lesion is responsible for the patient's symptoms. Fractional... more
A considerable number of patients present a single intermediate lesion (>40% and <70%) in one coronary artery on coronary angiography, with no clear evidence that the lesion is responsible for the patient's symptoms. Fractional flow reserve is a method of evaluating the functional importance of stenosis, a value of <0.75 indicating hemodynamically significant lesions. The aim of this study is to determine the safety of non-revascularization of an angiographically moderate and hemodynamically non-significant lesion. Fractional flow reserve (FFR) was evaluated in 87 patients over a period of 34 months. Retrospective analysis and follow-up were conducted of patients referred for coronary angiography, without acute coronary syndrome, who presented an angiographically moderate lesion of a single epicardial coronary artery with an FFR of 0.75, and in whom intervention was deferred. We found 21 patients with a mean age of 66 years, 66.7% male. All patients presented vascular r...
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Mitral stenosis is the most common valvular heart lesion found in pregnancy. When severe, it leads to significant maternal and fetal morbidity and mortality, since the hemodynamic adaptations to pregnancy are badly tolerated. Pregnancy... more
Mitral stenosis is the most common valvular heart lesion found in pregnancy. When severe, it leads to significant maternal and fetal morbidity and mortality, since the hemodynamic adaptations to pregnancy are badly tolerated. Pregnancy can lead to development of heart failure in patients with asymptomatic or even unknown mitral stenosis, as a result of the increased mitral valve pressure gradient caused by the physiologic increase in heart rate and blood volume in pregnancy. When symptoms persist despite optimal medical therapy, the poor prognosis justifies the correction of mitral stenosis during pregnancy. To present our experience in treating severe mitral stenosis in women who develop severe heart failure during pregnancy, using percutaneous balloon mitral valvuloplasty. From 1996 to March 2002, in our department, 47 balloon mitral valvuloplasties were successfully performed in women, three of them pregnant. These were patients with congestive heart failure, New York Heart Assoc...
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To compare the efficacy, safety and morbidity of surgical versus percutaneous atrial septal defect (ASD) closure. We studied all cases of ASD closure (surgical or percutaneous) performed in our hospital during the last 5 years. We... more
To compare the efficacy, safety and morbidity of surgical versus percutaneous atrial septal defect (ASD) closure. We studied all cases of ASD closure (surgical or percutaneous) performed in our hospital during the last 5 years. We analyzed the clinical and echocardiographic characteristics of both groups and compared the success rate of the procedure, events, days of hospital stay and evolution during the 1st year. 63 patients (pts) with ostium secundum ASD were treated in our hospital in the last 5 years; 25 (60% female) underwent surgery (A) while 38 (68% female) underwent percutaneous closure with an Amplatzer device (B); mean age was 38 (13-67) and 40 years (15-72), respectively. Dyspnea and fatigue were the most frequent symptoms in both groups (57% A; 29% B), while the most frequent signs were fixed splitting of S2 (78% A; 88% B) and systolic murmur at the left sternal border (82% A; 87% B). Previous ECG presented incomplete right bundle branch block in 63% of both groups. The...
Research Interests: Adolescent, Humans, Female, Male, Follow-up studies, and 4 moreAged, Middle Aged, Adult, and Retrospective Studies
1. Rev Port Cardiol. 2003 Jan;22(1):139-41. Coronary-subclavian steal syndrome: an unusual cause of angina in a patient with previous coronary bypass artery. [Article in English, Portuguese]. Dias A, Araújo D, Rodrigues A, Gonçalves M,... more
1. Rev Port Cardiol. 2003 Jan;22(1):139-41. Coronary-subclavian steal syndrome: an unusual cause of angina in a patient with previous coronary bypass artery. [Article in English, Portuguese]. Dias A, Araújo D, Rodrigues A, Gonçalves M, Braga P, Ribeiro VG. ...
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Transcatheter device occlusion of atrial septal defects is becoming an effective alternative to surgery. In order to avoid the discomfort of transesophageal echocardiography and the need for general anesthesia we started using... more
Transcatheter device occlusion of atrial septal defects is becoming an effective alternative to surgery. In order to avoid the discomfort of transesophageal echocardiography and the need for general anesthesia we started using intracardiac ultrasound (ICUS) to guide device implantation in adult patients. To assess the efficacy and safety of transcatheter closure of atrial septal defect (ASD) and patent foramen ovale (PFO) assisted by ICUS. Between April 2001 and November 2002, 27 patients with ASD and four patients with PFO were selected for transcatheter device occlusion. Patient selection was based on previous transesophageal echocardiogram and clinical data. All patients were treated without anesthesia or sedation. The percutaneous occlusion technique was assisted by ICUS and fluoroscopy. Morphological aspects of the defect and measurement of its largest diameter were used to select device diameter. Thirty-one patients were treated (27 with ASD, four with PFO); 21 (68%) were fema...
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Research Interests:
We report the case of a 77-year-old man with heart failure (NYHA class IV), angina (CCS class III) and multiple comorbidities. The evaluation showed severe aortic sten osis and left main coronary disease. Due to the very high... more
We report the case of a 77-year-old man with heart failure (NYHA class IV), angina (CCS class III) and multiple comorbidities. The evaluation showed severe aortic sten osis and left main coronary disease. Due to the very high perioperative risk, conventional surgery was denied. It was therefore decided to perform a combined percutaneous intervention. First, left main PCI was successfully performed. A few days later, a percutaneous aortic valve prosthesis was implanted via a femoral approach using the CoreValve ReValving system. Immediately after prosthesis implantation, the control angiogram showed severe paravalvular aortic regurgitation, which was corrected by implanting another percutaneous aortic prosthesis inside the first one (valve-in-valve procedure). During follow-up the patient experienced a remarkable improvement in hemodynamic and clinical status. We demonstrate that the combination of two different percutaneous interventions in severe aortic and coronary disease is feas...
Research Interests:
Transcatheter aortic valve implantation has been increasingly reported as an alternative to the surgical management of aortic stenosis in patients who are contraindicated for surgery. Transcatheter technical limitations for vascular... more
Transcatheter aortic valve implantation has been increasingly reported as an alternative to the surgical management of aortic stenosis in patients who are contraindicated for surgery. Transcatheter technical limitations for vascular access in some patients created the need for alternative approaches as is the case of the subclavian artery access. The authors report their experience and results in a group of four patients treated with transcatheter aortic valve implantation through subclavian artery access.
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... Fotocópia. Texto completo SciELO Brasil (texto : PT). experimental, Documentos relacionados. Id: 500375, LILACS-Express. Autor: Rodrigues, Aluízio; Gonçalves, Manuel Domingos da Cruz; Ferreira, Marco Antônio Menezes; Velloso, José... more
... Fotocópia. Texto completo SciELO Brasil (texto : PT). experimental, Documentos relacionados. Id: 500375, LILACS-Express. Autor: Rodrigues, Aluízio; Gonçalves, Manuel Domingos da Cruz; Ferreira, Marco Antônio Menezes; Velloso, José Gonçalves; Vieira, Orlando Marques. ...
Percutaneous aortic valve implantation is an emerging procedure for the treatment of patients with severe aortic stenosis. The procedure was performed in patients with severe symptomatic aortic stenosis, who had been refused for aortic... more
Percutaneous aortic valve implantation is an emerging procedure for the treatment of patients with severe aortic stenosis. The procedure was performed in patients with severe symptomatic aortic stenosis, who had been refused for aortic valve replacement surgery. A self-expanding bioprosthesis within a nitinol frame delivered by an 18F catheter was used. Most of the procedures were performed through a femoral artery approach and under local anesthesia and sedation. Thirty-two patients were treated, mean age 80 years, with various comorbidities and mean logistic EuroSCORE of 22%. The procedure was successful in all patients, with a significant improvement in transvalvular gradients. Two patients died due to procedure-related complications. The most common complications were vascular access related and high-degree atrioventricular block requiring permanent pacemaker. No events were reported after one month follow-up, with most patients showing improvement in functional capacity. After ...
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Previous studies have evaluated the prognostic impact of early invasive strategies in the management of non-ST elevation acute coronary syndromes (NSTEACS). There is, however, conflicting evidence about the advantages of such an approach.... more
Previous studies have evaluated the prognostic impact of early invasive strategies in the management of non-ST elevation acute coronary syndromes (NSTEACS). There is, however, conflicting evidence about the advantages of such an approach. In some studies the benefits are dependent on gender or age, while time to angiography varies between studies. We performed a retrospective analysis of 222 patients admitted with NSTEACS between 1/1/2004 and 12/31/2004. The patients initially received intensive medical therapy and were divided into three groups according to the subsequent approach. In the early invasive strategy group (EIS; n = 62), angiography was performed in the first 48 hours; in delayed invasive strategy (DIS; n = 97), angiography was routinely performed but postponed beyond the first 48 hours; in the conservative strategy group (CS; n = 63), catheterization was performed only in cases of refractory angina or evidence of ischemia in non-invasive tests. We evaluated the occurre...
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Base de dados : LILACS. Pesquisa : 496425 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo SciELO... more
Base de dados : LILACS. Pesquisa : 496425 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo SciELO Brasil (texto : PT). Id: 496425, LILACS-Express ...
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For years, the treatment of high-risk pulmonary embolism (PE) was based on two well-defined strategies: thrombolysis, whose benefits have been documented in randomized trials, and surgical embolectomy. However, mechanical reperfusion by... more
For years, the treatment of high-risk pulmonary embolism (PE) was based on two well-defined strategies: thrombolysis, whose benefits have been documented in randomized trials, and surgical embolectomy. However, mechanical reperfusion by percutaneous techniques is used in an increasing number of patients, and is a valid therapeutic option when there is a formal contraindication to thrombolysis, as rescue therapy when thrombolysis fails to improve hemodynamics, and/or when emergency surgical thrombectomy is unavailable or contraindicated. This article discusses the indications for the use of percutaneous techniques in PE, reports the initial experience of our center with the AngioJet® thrombectomy device (Possis Medical Inc, Minneapolis, MN, USA) and reviews the available evidence, the most recent recommendations and the main complications associated with this procedure.
Thoracic endovascular aortic repair (TEVAR) is a minimally invasive technique which is increasingly used in different thoracic aortic pathologies such as aortic aneurysm, complicated type B aortic dissection, aortic trauma, intramural... more
Thoracic endovascular aortic repair (TEVAR) is a minimally invasive technique which is increasingly used in different thoracic aortic pathologies such as aortic aneurysm, complicated type B aortic dissection, aortic trauma, intramural hematoma and penetrating aortic ulcer. In this paper we discuss the main indications for endovascular stent-grafts in the treatment of thoracic aortic disease, based on three cases in which this procedure was used for three different conditions: degenerative aneurysm, complicated type B dissection and post-traumatic injury. These case reports add to the evidence that TEVAR is a safe and feasible therapeutic alternative in selected patients with thoracic aortic disease, improving aortic remodeling, with relatively low morbidity and mortality. The main complications and difficulties related to the procedure are also discussed.
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Pulmonary arterial hypertension (PAH) is a serious and progressive disease, potentially fatal in a few years. Until the 1990s the only effective treatment for this disease was pulmonary/cardiopulmonary transplant. Over the last few years... more
Pulmonary arterial hypertension (PAH) is a serious and progressive disease, potentially fatal in a few years. Until the 1990s the only effective treatment for this disease was pulmonary/cardiopulmonary transplant. Over the last few years several drugs have emerged that have modified the course of the disease. To characterise patients with PAH followed at Centro Hospitalar de V.N.Gaia between 2000 and 2006. To raise awareness of this entity. Retrospective analysis of all patients with PAH or chronic thromboembolic pulmonary hypertension (CTEPH) followed at our Hospital. In this period 11 patients were observed, 7 women and 4 men, with a mean age of 43 y. Five patients had idiopathic PAH, three had CTEPH, two had PAH associated with interauricular communication and one had PAH associated with CREST Syndrome. At the time of diagnosis most patients were in NYHA/ /WHO Functional Class III/IV, mean systolic pulmonary artery pressure was 98+/-32 mm Hg and mean distance walked in the 6-minute walk test was 401 m. Initial treatment: Three patients had inhaled iloprost, two subcutaneous treprostinil, three oral bosentan, one oral sildenafil and two patients under- went surgery. Mean follow-up time was 28.1 months. Five patients recovered, three are stable, one worsened and two died. PAH is a serious illness which requires a multidisciplinary approach with the need for complex and expensive therapies. Diagnosis in initial sta- ges is essential for an effective treatment.
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Resumen: A adubação nitrogenada é importante para potencializar a produtividade do milho safrinha, que se tornou a principal cultura de outono-inverno, semeada após a soja, nos seguintes Estados: Paraná, São Paulo, Mato Grosso do Sul,... more
Resumen: A adubação nitrogenada é importante para potencializar a produtividade do milho safrinha, que se tornou a principal cultura de outono-inverno, semeada após a soja, nos seguintes Estados: Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso e Goiás. ...
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página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo SciELO Brasil. experimental, Documentos relacionados. Id: 356021. Autor: Lacativa, Paulo Gustavo S; PatrícioFilho, Pedro José M; Gonçalves, Manuel D. Cruz;... more
página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Texto completo SciELO Brasil. experimental, Documentos relacionados. Id: 356021. Autor: Lacativa, Paulo Gustavo S; PatrícioFilho, Pedro José M; Gonçalves, Manuel D. Cruz; Farias, Maria Lucia F. de. ...
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Supranumerary or ectopic parathyroid glands are the main cause of persistent hyperparathyroidism (HPT) in patients with end stage renal disease (ESRD) submitted to parathyroidectomy (PTx). To evaluate the prevalence and location of... more
Supranumerary or ectopic parathyroid glands are the main cause of persistent hyperparathyroidism (HPT) in patients with end stage renal disease (ESRD) submitted to parathyroidectomy (PTx). To evaluate the prevalence and location of parathyroid glands in these patients. Thirty-five patients with ESRD and severe secondary hyperparathyroidism (HPT2) had been submitted to total PTx at HUCFF from December 2001 to July 2005. Surgery was always performed by the same surgeon, who described in details the location of the glands. Sixteen patients (45.7%) had ectopic glands, which were also extranumerary in five of them (14.3%). The most common locations were the thyroid parenchyma (33.3%), thyroid-thymus conduit (18.5%), and thymus (14.8%). Before PTx, the sensibility of ultrasonography and scintigraphy with technetium-99m Sestamibi was low (48.3% and 35.3%, respectively). Moreover, 51.4% of the nodules found at US were thyroid nodules. However, 99mTc-Sestamibi was useful to identify ectopic glands in those two patients with persistent HPT after PTx. The presence of extranumerary and ectopic parathyroid glands in HPT2 is sufficiently important to justify their exhaustive search. As the preoperative image exams present low sensibility to locate them, it is necessary to develop an exploratory routine embracing the most common sites of location.
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Background: Intravascular ultrasound (IVUS) is currently used to study lesions during transcatheter coronary therapy. However, before dilation some lesions cannot be reached or crossed with the imaging catheter.Hypothesis: This study... more
Background: Intravascular ultrasound (IVUS) is currently used to study lesions during transcatheter coronary therapy. However, before dilation some lesions cannot be reached or crossed with the imaging catheter.Hypothesis: This study seeks to elucidate which factors determine the feasibility of IVUS examination before coronary interventions.Methods: Accordingly, 100 consecutive patients undergoing IVUS examination before coronary angioplasty were prospectively studied. The clinical and angiographic characteristics of 77 patients with a successful IVUS study (Group A) were compared with those of 23 patients in whom IVUS was attempted but the target lesion could not be interrogated (Group B). The echogenic characteristics of the target lesion [before (n = 77) or after intervention (in 18 patients in Group B)] were also studied.Results: Patients in Group B were significantly older (62 ± 7 vs. 57 ± 10 years, p < 0.05) and more frequently had stable angina [8 (35%) vs. 9 (11%), p < 0.05]. The distribution of lesions within the coronary tree and angiographic lesion characteristics including length, eccentricity, calcification, bend location, and the American College of Cardiology/American Heart Association classification were similar in both groups. However, proximal tortuosities (>45° at end diastole) were more frequently found in Group B [20 (87%) vs. 47 (61%), p < 0.05]. In addition, by quantitative angiography, patients in Group B had smaller arteries (reference diameter 2.8 ± 0.4 vs. 3.1 ± 0.4 mm, p < 0.05) and more severe lesions (minimal lumen diameter 0.46 ± 0.24 vs. 0.65 ± 0.34 mm, p < 0.05). On IVUS, calcified lesions were more frequently visualized in Group B (61 vs. 38%, p < 0.05). On multivariate analysis, catheter size, baseline minimal lumen diameter, angiographic proximal tortuosities, and lesion calcification on imaging were independent predictors of the feasibility of IVUS studies.Conclusions: Unsuccessful IVUS studies before intervention occur more frequently (1) in vessels with proximal tortuosities or severe lumen narrowing, (2) in lesions that are calcified on IVUS, and (3) when large imaging catheters are used.