João L. A. A. Falcão

Evidences of possible necrotic-core artifact around dense calcium in Virtual Histology images

Virtual Histology (VH) is a new medical imaging technique that allows the assessment of atherosclerotic plaque composition, a potential useful tool for the evaluation of individuals with coronary disease. Empirical observation has suggested that plaque areas adjacent to dense calcium (DC) are frequently coded as necrotic core (NC) in VH images. The main objective of the study was to evaluate whether the presence of DC induces an artifactual coding of NC in adjacent structures. To test this effect, a set of 89 coronary arteries segments have been analyzed in baseline and after stent implantation, which are coded as dense calcium into VH images. Necrotic tissue has risen significantly after stenting, especially in regions surrounding dense calcium structures, reinforcing the hypothesis of an artifactual relationship between those plaque components.

Prevalência de doença arterial coronariana e avaliação pré-operatória em portadores de valvopatia

BACKGROUND: Coronary angiography has been indicated in the preoperative phase for patients with valvopathy over 35 years of age. However, the actual prevalence of obstructive coronary artery disease (CAD) in this population has been little studied. OBJECTIVE: To assess the prevalence of and the risk factors for CAD in candidates for valve surgery in Brazil. METHODS: Coronary angiography was performed in 3,736 patients who were candidates for valve surgery; prevalence of and risk factors for CAD associated with valvopathy were assessed. RESULTS: CAD was associated with valvopathy in 121 patients (prevalence of 3.42%). In 79 patients (68.1%), CAD was diagnosed by means of preoperative coronary angiography. Of these 79 patients, 50 (63.3%) had isolated aortic valvopathy or aortic valvopathy associated with mitral valvopathy. Smoking habit was observed in 54 patients (68.3%), hypertension in four (43%), family history in 24 (30.3%), diabetes mellitus in 15 (18.9%), and obesity in eight (10.1%). Of the 121 patients, 95.7% were over 50 years of age. Only five (4.3% of the patients with CAD) were below 50 years of age, and all of them had at least one risk factor for CAD. CONCLUSION: CAD prevalence was low in the patients studied. Aortic valvopathy was the most frequent valvopathy associated with CAD, and most patients were over 50 years of age. The ideal age for routine preoperative coronary angiography in patients with valvopathy should be reassessed.

Comparison between MDCT and Grayscale IVUS in a Quantitative Analysis of Coronary Lumen in Segments with or without Atherosclerotic Plaques.

Background The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. Objectives We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. Methods The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. Results At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. Conclusions In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques.

Pseudoaneurisma de ventrículo esquerdo associado a insuficiência mitral grave complicando infarto agudo do miocárdio ínfero-látero-dorsal

We described a case of left ventricular pseudoaneurysm associated to a severe mitral regurgitation, complicating a inferolaterodorsal acute myocardial infarction. The lesion was found in a routine echocardiogram during the in-hospital follow-up. The well-succeeded surgical strategy and the good clinical evolution of the patient were distinguished.

Avaliação ultrassonográfica intracoronária da carga aterosclerótica no tronco da artéria coronária esquerda prediz a extensão da doença no restante da árvore coronária: análise piloto

BACKGROUND: Non-cardiac atherosclerotic imaging, including carotid ultrasound, has been proposed as an indirect way to estimate coronary risk. The authors hypothesize that the isolated assessment of the left main coronary artery (LMCA) could predict the atherosclerotic burden in the remainder of the coronary tree. METHODS: The study included patients with a diagnosis of coronary artery disease with an indication for percutaneous coronary intervention (PCI), without significant LMCA stenosis. During PCI, LMCA and three-vessel intravascular ultrasound (IVUS) examination was performed and the lumen area, external elastic membrane area, plaque area, and plaque burden were measured. RESULTS: A total of 17 patients were included with mean age of 56 ± 8.9 years, 71% male, and 41% diabetics. Although none of the patients had LMCA stenosis by angiography or IVUS, evidence of atherosclerosis was observed with a plaque area of 8.4 ± 2.7 mm2 and plaque burden of 33.5 ± 8.9%. A significant correlation between the LMCA and the rest of the coronary arteries was observed for all IVUS parameters: lumen area (r = 0.5), external elastic membrane area (r = 0.7); plaque area (r = 0.6), and plaque burden (r = 0.4). CONCLUSIONS: In this pilot study, the coronary atherosclerotic burden could be estimated from the isolated assessment of the LMCA by IVUS. Such an association is relevant for the development of future coronary risk scores, as a surrogate marker of the global coronary tree atherosclerotic burden.

Perfil de segurança dos stents farmacológicos nas síndromes coronárias agudas: dados do Registro INCOR

BACKGROUND: Drug-eluting stents are a great advance in the treatment of coronary disease. However, their use in patients with acute coronary syndromes has been the subject of intense scientific debate. METHODS: 910 consecutive patients treated with at least one drug-eluting stent between May 2002 and September 2006 were enrolled in the present analysis. The patients were assigned to 2 groups according to their clinical condition at the time of admission: 1) Stable group (635 patients with stable angina) and 2) Acute group (275 patients with NSTEMI). We analyzed the clinical and angiographic characteristics as well as the occurrence of late adverse events. RESULTS: The clinical characteristics of the groups were similar, except for the highest incidence of smokers in the acute group and previous percutaneous intervention in the stable group. After 588 days (median follow-up period), the stable and acute groups had similar rates of re-infarction (2.8 vs. 5.0%; p = 0.1), target vessel revascularization (6.0 vs. 7.7%; p = 0.4), death (4.5 vs. 6.5%; p = 0.2) and composite major adverse cardiac events (9.9 vs. 11.9%; p = 0.4), respectively. However, the occurrence of in-stent thrombosis was more frequent in patients with acute coronary diseases (1.4 vs. 4.4%; p = 0.02), mainly due to the occurrence of thrombosis within the first year after implantation (1.1 vs. 4.4%; p = 0.01). CONCLUSION: Drug-eluting stents have shown a good safety profile in patients with acute coronary syndromes compared to those with chronic coronary disease, despite the higher incidence of late in-stent thrombosis.

Post-Processing Analysis of Virtual Histology Images - A New Tool for Intra-Plaque Component Assessment

Virtual Histology (VH) is a new medical imaging technique that allows the assessment of atheroscletoric plaque composition, a potential useful tool for the evaluation of individuals with coronary disease. In its default output, VH provides a frame-by-frame assessment of the summed absolute and relative areas of each plaque component. However, no information is currently available on the intra-plaque distribution of each component. Also, current VH analysis lack information on the presence and extension of confluent pools, which may have important pathophysiological implications. We, therefore, developed a software to extract these informations from VH images. A total of 897 coronary crosssections from 23 patients were analysed. Overall, 57% of patients were male, the average age was 58 ± 9 years and 39% were diabetics.

A Novel Algorithm to Quantify Coronary Remodeling Using Inferred Normal Dimensions

Background Vascular remodeling, the dynamic dimensional change in face of stress, can assume different directions as well as magnitudes in atherosclerotic disease. Classical measurements rely on reference to segments at a distance, risking inappropriate comparison between dislike vessel portions. Objective to explore a new method for quantifying vessel remodeling, based on the comparison between a given target segment and its inferred normal dimensions. Methods Geometric parameters and plaque composition were determined in 67 patients using three-vessel intravascular ultrasound with virtual histology (IVUS-VH). Coronary vessel remodeling at cross-section (n = 27.639) and lesion (n = 618) levels was assessed using classical metrics and a novel analytic algorithm based on the fractional vessel remodeling index (FVRI), which quantifies the total change in arterial wall dimensions related to the estimated normal dimension of the vessel. A prediction model was built to estimate the normal dimension of the vessel for calculation of FVRI. Results According to the new algorithm, “Ectatic” remodeling pattern was least common, “Complete compensatory” remodeling was present in approximately half of the instances, and “Negative” and “Incomplete compensatory” remodeling types were detected in the remaining. Compared to a traditional diagnostic scheme, FVRI-based classification seemed to better discriminate plaque composition by IVUS-VH. Conclusion Quantitative assessment of coronary remodeling using target segment dimensions offers a promising approach to evaluate the vessel response to plaque growth/regression.

Comparação de segmentos angiograficamente normais e com estenose luminal significativa avaliados pelo ultrassom intracoronário com histologia virtual: análise piloto

INTRODUCAO: A doenca arterial coronaria (DAC) e sabidamente difusa, podendo acometer multiplos segmentos arteriais. No entanto, quando se analisa a angiografia coronaria, e comum a concomitância, em um mesmo paciente, da presenca de lesao em um segmento e da ausencia de obstrucao em outros. Por se tratar de um luminograma, a angiografia apresenta limitacoes para o diagnostico da DAC. Neste estudo utilizou-se o ultrassom intracoronario com histologia virtual (USIC-HV) para avaliar a presenca e a composicao de placas ateroscleroticas em segmentos angiograficamente normais e com lesoes em pacientes com DAC estabelecida. METODOS: No total, 17 pacientes com DAC obstrutiva encaminhados para realizacao de angioplastia foram submetidos a USIC-HV dos tres grandes vasos epicardicos. Apos analise minuciosa da angiografia, foram selecionados 32 segmentos angiograficamente normais, os quais foram comparados a outros 19 segmentos coronarios com estenose luminal > 70%. RESULTADOS: A carga de placa media em segmentos sem lesao angiografica foi de 47,3 ± 15,1%, enquanto em segmentos com estenose angiografica foi de 76,2 ± 8,8% (P < 0,01). A composicao da placa diferiu entre os segmentos. Placas nos segmentos angiograficamente normais apresentavam maior componente fibrolipidico (17 ± 11% vs. 11,4 ± 12%; P = 0,045) e menor componente necrotico (13,1 ± 13% vs. 20,2 ± 12%; P = 0,03). CONCLUSOES: Nesta analise piloto, em pequeno grupo de pacientes portadores de DAC, observou-se que segmentos angiograficamente normais frequentemente apresentam placa aterosclerotica. A composicao da placa em segmentos angiograficamente normais, entretanto, diferiu daquela em segmentos com lesao, sugerindo a coexistencia de estagios distintos do processo aterosclerotico em um mesmo paciente.

Associação entre a densidade radiológica da placa à tomografia de coronárias com 64 colunas de detectores e a composição da placa ao ultrassom intravascular com técnica de histologia virtual: resultados de uma comparação pareada prospectiva

BACKGROUND: Little is known about the comparative results of coronary plaque assessment by multidetector computed tomography (MDCT) against the novel intravascular ultrasound virtual histology (IVUS-VH). METHOD: Threevessel IVUS-VH and MDCT were prospectively obtained from 21 patients. Each vessel was divided into 4-mm subsegments, which were used as the basic unit for analysis. The 4-mm subsegments were matched by their axial location. Lumen and outer vessel boundaries for IVUS-VH and for MDCT were traced by specific automatic softwares. The percent contribution of each IVUS-VH plaque tissue type and the ratio of necrotic tissue to calcium were quantified. The MDCT plaque was evaluated through its average density in Hounsfield units (HU). RESULTS: A total of 641 matched subsegments were computed from 70 vessels. Overall, the average IVUS-VH tissue composition was: fibrous = 64%; fibrofatty = 20%; necrotic tissue = 11%; dense calcium = 5%; and calcium/necrosis ratio = 5.1. MDCT average plaque attenuation ranged from 44 to 440 HU and was divided into three groups of similar size (1st tertile: 44-128 HU; 2nd tertile: 129-178 HU; 3rd tertile: 178-440 HU). There was an inverse correlation between IVUS-VH necrotic/ dense calcium ratio and MDCT plaque density (1st tertile: 4.1, 2nd tertile: 2.9, 3rd tertile: 2.3; P < 0.01) and a direct relationship between percent IVUS-VH dense calcium and MDCT plaque density (1st tertile: 1.5%, 2nd tertile: 2.5%, 3rd tertile: 3.8%; P < 0.01). CONCLUSION: Atherosclerotic plaque density evaluated by 64-MDCT significantly associates with plaque composition assessed by IVUS-VH.