Breno de Alencar Araripe Falcão

Three-dimensional reconstruction of coronary arteries and plaque morphology using CT angiography – comparison and registration with IVUS

BackgroundThe aim of this study is to present a new methodology for three-dimensional (3D) reconstruction of coronary arteries and plaque morphology using Computed Tomography Angiography (CTA).MethodsThe methodology is summarized in six stages: 1) pre-processing of the initial raw images, 2) rough estimation of the lumen and outer vessel wall borders and approximation of the vessel’s centerline, 3) manual adaptation of plaque parameters, 4) accurate extraction of the luminal centerline, 5) detection of the lumen - outer vessel wall borders and calcium plaque region, and 6) finally 3D surface construction.ResultsThe methodology was compared to the estimations of a recently presented Intravascular Ultrasound (IVUS) plaque characterization method. The correlation coefficients for calcium volume, surface area, length and angle vessel were 0.79, 0.86, 0.95 and 0.88, respectively. Additionally, when comparing the inner and outer vessel wall volumes of the reconstructed arteries produced by IVUS and CTA the observed correlation was 0.87 and 0.83, respectively.ConclusionsThe results indicated that the proposed methodology is fast and accurate and thus it is likely in the future to have applications in research and clinical arena.

A Tale of Two Cities: STEMI Interventions in Developed and Developing Countries and the Potential of Telemedicine to Reduce Disparities in Care

OBJECTIVES To utilize telemedicine as a foundation platform for creating population-based STEMI networks. BACKGROUND Disparate acute myocardial infarction (AMI) management occurs in developed and developing countries on account of differences in infrastructure resources. As a result, developed countries utilize primary percutaneous coronary intervention (PCI) and second- and third-generation thrombolytic therapy, in contrast to developing countries, which primarily rely on earlier-generation thrombolytic therapy and basic medical management. Reducing the vast gap in AMI care between developed and developing countries is an abysmally slow process. METHODS Remote access, telemedicine IT platforms, expert EKG interpretation, teleconsultation, and a strict quality assurance process are incorporated into a population-based AMI network. RESULTS Lumen Americas Telemedicine Infarct Network (LATIN) is an applied hub-and-spoke strategy, which creates a telemedicine-based STEMI management network across large populations. Primary PCI with targeted door-to-balloon times is the preferred strategy for the hub sites. Telemedicine-guided accurate EKG interpretation and teleconsultation are applied at the spoke sites. An integrated IT platform is used to navigate an effective prehospital triage system. The pilot phase has created 100 LATIN sites in Brazil and Colombia. CONCLUSION Telemedicine provides an attractive strategy to reduce the gaps that presently exist in managing AMI in developed and developing countries.

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.

Validation of coronary computed tomography angiography scores for non-invasive assessment of atherosclerotic burden through a comparison with multivessel intravascular ultrasound

AIMS While the atherosclerotic plaque volume can be manually quantified in coronary computed tomography angiography (CTA) it is impractical for clinical routine use. Several anatomical scores have been developed as surrogates for overall atherosclerotic burden in coronary CTA and even proven to be highly predictive for future adverse events. However, they have not been validated against the gold standard for atherosclerotic burden, intra-vascular ultrasound (IVUS). In the present study we have compared several coronary CTA scores with the coronary IVUS. METHODS AND RESULTS A total of 62 patients with diagnosed coronary disease scheduled for percutaneous intervention were prospectively enrolled. For all patients, coronary CTA and multivessel IVUS were obtained. Calcium score and 6 previously reported scores were calculated from coronary CTA imaging and compared to average IVUS-derived percent atheroma volume (PAV). On average, 3.8 ± 0.7 vessels, comprising 123.8 ± 31.3 mm in length, were imaged with IVUS per patient. All but one previously described scoring systems showed a significant association with IVUS-derived PAV. Among them, the SSS score demonstrated the strongest correlation with IVUS-PAV (r = 0.61, p < 0.001) and the greatest area under the ROC curve (C-statistic = 0.87), to predict a high PAV. CONCLUSIONS Most frequently used coronary CTA scores have a good correlation with global coronary atherosclerotic burden measured by multivessel IVUS derived atheroma volume. Among them, the SSS score shows the best performance being a good non-invasive alternative to IVUS for global coronary atherosclerotic burden assessment.

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.

Atrioventricular block pathology in cardiomyopathy by desmin deposition

Generally, restrictive cardiomyopathy due to desmin deposition is characterized by restriction to ventricular diastolic filling and different degrees of atrioventricular block (AVB). In this report, we describe the pathological changes of the cardiac conduction system related to AVB. The sinus node, the compact node, and the penetrating bundle (bundle of His) had no abnormalities, however, there was extensive fibrosis of the terminal portions of the branching bundle and the beginning of the left and right bundles at the top of the ventricular septum. The pathogenesis of this fibrous replacement is probably the same that leads to extensive fibrosis of the working ventricular myocardium, and remains to be elucidated.Geralmente, a cardiomiopatia restritiva por deposicao de desmina e caracterizada pela restricao ao enchimento diastolico ventricular e por diferentes graus de bloqueio atrioventricular (BAV). Neste relato, sao descritas as alteracoes anatomopatologicas do sistema de conducao cardiaco relacionadas ao BAV. O no sinusal, o no compacto e o feixe penetrante (feixe de His) nao apresentavam anormalidades, entretanto, havia extensa fibrose das porcoes terminais do feixe ramificante e do inicio dos feixes esquerdo e direito, no topo do septo ventricular. A patogenia dessa substituicao fibrosa e provavelmente a mesma que origina a extensa fibrose do miocardio ventricular contratil, e permanece por ser elucidada.

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.

Clinical performance of a novel ultrathin strut, low-dose, sirolimus-eluting stent with abluminal-only biodegradable polymeric coating for patients undergoing percutaneous coronary intervention in the daily practice

BACKGROUND The present study aimed to evaluate the clinical performance, in the daily practice of a busy catheterization laboratory, of a novel drug-eluting stent (DES) built with an ultra-thin-strut metallic platform, eluting sirolimus at low doses, abluminal coated with biodegradable polymers, and mounted in a low-compliant delivery system. METHODS Prospective, single-arm study, comprising all consecutive patients undergoing percutaneous coronary intervention (PCI) with the Inspiron™ sirolimus-eluting stent (SES) (Scitech, Aparecida de Goiania, Brazil). The primary endpoint was the occurrence of major adverse cardiac events (MACE) [cardiac death, non-PCI related myocardial infarction (MI), or target vessel revascularization (TVR)]. RESULTS A total of 470 patients were included, from which 51.3% were diabetics, 33.8% had triple-vessel disease, 15.3% had heart failure, 38.9% had at least one bifurcation treated, 19.8% were treated for a bare metal stent restenosis, and 61.9% had at least one type C lesion; one or more of these features were found in 96.0%. At 300 days, the rate target lesion revascularization was 5.4% and the rate of MACE was 8.1%. The incidence of definite or probable stent thrombosis was 0.4%, with no cases between 30 and 300 days. CONCLUSIONS The novel stent is associated with excellent short and mid-term clinical outcomes in patients treated with PCI in the daily practice.

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.

Aortic Counterpulsation Therapy in Patients with Advanced Heart Failure: Analysis of the TBRIDGE Registry

Background The use of aortic counterpulsation therapy in advanced heart failure is controversial. Objectives To evaluate the hemodynamic and metabolic effects of intra-aortic balloon pump (IABP) and its impact on 30-day mortality in patients with heart failure. Methods Historical prospective, unicentric study to evaluate all patients treated with IABP betwen August/2008 and July/2013, included in an institutional registry named TBRIDGE (The Brazilian Registry of Intra-aortic balloon pump in Decompensated heart failure - Global Evaluation). We analyzed changes in oxygen central venous saturation (ScvO2), arterial lactate, and use of vasoactive drugs at 48 hours after IABP insertion. The 30-day mortality was estimated by the Kaplan-Meier method and diferences in subgroups were evaluated by the Log-rank test. Results A total of 223 patients (mean age 49 ± 14 years) were included. Mean left ventricle ejection fraction was 24 ± 10%, and 30% of patients had Chagas disease. Compared with pre-IABP insertion, we observed an increase in ScvO2 (50.5% vs. 65.5%, p < 0.001) and use of nitroprusside (33.6% vs. 47.5%, p < 0.001), and a decrease in lactate levels (31.4 vs. 16.7 mg/dL, p < 0.001) and use of vasopressors (36.3% vs. 25.6%, p = 0.003) after IABP insertion. Thirty-day survival was 69%, with lower mortality in Chagas disease patients compared without the disease (p = 0.008). Conclusion After 48 hours of use, IABP promoted changes in the use of vasoactive drugs, improved tissue perfusion. Chagas etiology was associated with lower 30-day mortality. Aortic counterpulsation therapy is an effective method of circulatory support for patients waiting for heart transplantation.