Assessing intermediate coronary lesions: angiographic prediction of lesion severity on intravascular ultrasound.

BACKGROUND: Intravascular ultrasound (IVUS) can detect atherosclerotic compromise in coronary segments where conventional angiography cannot. However, IVUS is more invasive, expensive and laborious than angiography. We compared the detection of stenosis by IVUS and angiography and identified angiographic predictors of severe luminal stenosis on IVUS in patients with angiographically-intermediate coronary lesions. METHODS: Fifty-six patients with myocardial ischemia and intermediate stenosis by quantitative coronary angiography (QCA) underwent IVUS assessment of the culprit artery. The results from IVUS and QCA were compared using the two-tailed unpaired t-test. Multiple regression analysis was performed to identify QCA parameters that could predict the presence of severe stenosis on IVUS, defined as a minimum luminal area (MLA) < or = 4 mm2. RESULTS: A total of 63 stenotic coronary lesions were classified as intermediate by QCA; 68% of these were found to be severe on IVUS. There was a weak correlation between IVUS and QCA with respect to percentage of stenosis, minimum luminal diameter, reference segment diameter and length of atherosclerotic compromise. In contrast, there was a significant difference in the assessment of reference segment luminal diameter, which was 2.83 +/- 0.56 mm by angiography versus 3.45 +/- 0.69 mm by IVUS (p < 0.0001). The only angiographic predictor of the presence of severe coronary stenosis on IVUS was a distal reference segment diameter < or = 2.42 mm. CONCLUSIONS: In patients with angiographically-intermediate lesions, the frequency of severe stenosis detected by IVUS was high, indicating that angiography underestimated the severity of stenosis. Distal reference segment diameter was the only predictor of a small MLA and could be used to stratify these lesions into groups with higher and lower risk of severe stenosis.

Terapia celular no tratamento da insuficiência cardíaca isquêmica / Cellular therapy in the treatment of ischemic heart failure

Neste artigo, os autores discutem o estado da arte da terapia celular no tratamento da insuficiencia cardiaca isquêmica. São apresentados os principais tipos celulares e suas particularidades no tratamento dessa doença.

In this article the authors discuss the state of the art on cell therapy for ischemic heart failure. The principal cell types and their specific characteristics for the treatment of this pathology are presented.

Regeneração cardíaca. Coração: um órgão pós-mitótico? / Cardiac regeneration: the heart: a postmitotic organ?

A apresentação de evidências de divisão celular e da existência de atividade reparativa intrínseca ao tecido miocárdico gerou uma mudança de paradigma na aceitação do coração como um órgão de população celular dinâmica, a qual atinge um estado de homeostasia a partir de um equilíbrio entre morte e replicação celular. Neste contexto, a terapia celular tenta dar respostas a questões básicas como: contexto clínico ideal para tratamento, tipo celular de escolha, dose e frequencia de tratamento e via de escolha para administração de células...

Evidence of myocardial tissue cell division and repair activities has generated a change of paradigm in accepting the heart as a dynamic cell organ reaching a state of homeostasis as of a point of equilibrium between cell death and replication. Against such scenario, cell therapy tries to find answers to basic issues such as: ideal clinical setting for treatment, cell type choice, dose and frequency for treatment, and choice cell administration.

Differential local effect of sirolimus eluting stent and paclitaxel eluting stent in a porcine restenosis model

Introdução: Os stents farmacológicos liberadores de sirolimus (SES) e de paclitaxel (PES) reduzem de maneira significativa os índices de reestenose se comparados aos stents de metal. Há muita controvérsia com relação aos possíveis efeitos indesejáveis do SES e do PES, como, por exemplo, a trombosesubaguda intra-stent. Este estudo teve como objetivo comparar o efeito arterial local do SES e do PES. Métodos: A dilatação coronariana foi induzida em 16 suínos pela insuflação de um balão superdimensionado na proporção 1.2:1.0 em 43 artérias. Foram olocados aleatoriamente 21 SES e 22 PES na descendente anterior esquerda e na circunflexa esquerda no local da lesão anterior por balão. Os animais foramenviados para necropsia 30 dias após o procedimento. Vinte artérias foram enviadas para análise pelo métodoWestern Blot (16 segmentos com stent + 4 controles normais). Vinte e sete segmentos com stent foram submetidos à análise histológica e à microscopia eletrônica (ME) a baixo vácuo. Resultados: Não foram observadas diferenças com referência às características morfométricas entre os dois grupos. A espessura neointimal se mostrou semelhante nos segmentos com stent SES e PES (0,23±0,05mm vs 0,21±0,08mm, respectivamente – p=0,08). A cicatrização arterial localavaliada pelo método WB demonstrou níveis significantemente mais altos do fator Von Willebrand e CD 31 em SESvs PES (p=0,005 e 0,03, respectivamente). PES demonstrou,ainda, inflamação local mais intensa, expressa pelos níveis mais altos de PDGF (p=0,0007). Este resultado foi corroborado pelos achados de reação inflamatória local mais intensa pela ME, expressa por dados inflamatórios mais elevados no grupo PES. Conclusão: PES demonstrou maior grau de inflamação e menor expressão de CD31 e do fator VonWillebrand, sugerindo, portanto, cicatrização endotelial comprometidaapós a colocação do stent se comparado ao SES.

Background: Sirolimus eluting stents (SES) and Paclitaxel eluting stents (PES) significantly reduce restenosis rates as compared with bare metal stents. There is much controversyregarding possible untoward effects of SES and PES such as subacute stent thrombosis. The present study aimed tocompare the local arterial effect of SES versus PES. Methods: In 16 pigs coronary overstretch was induced by inflating an oversized angioplasty balloon at 1.2:1.0 ratio in 43 arteries. Twenty one SES and 22 PES were randomly deployed in LAD and LCx in the site of previous balloon injury. Animals were sent to necropsy 30 days after the procedure. Twenty arteries were sent to Western Blot (WB) analysis (16 stented segments plus 4 normal controls). Twenty seven stented segments were submitted to histologyanalysis and low vacuum electron microscopy (EM). Results: There were no differences regarding arterial morphometric characteristics between the two groups. Neo intimal thicknesswere similar in SES and PES stented segments (0.23±0.05mm vs 0.21±0.08mm, respectively – p=0.08). Local arterial healing assessed by WB showed significantly higher local levels of Von Willebrand factor and CD 31 in SES vs PES (p values of 0.005 and 0.03, respectively). Also, PES showed higher local inflammation as expressed byhigher PDGF levels (p= 0.0007). This result was corroborated by the EM findings of higher local inflammatory reaction, expressed by higher inflammation scores in the PES group.Conclusion: PES showed higher inflammation and lower expression of CD31 and Von Willebrand factor, suggesting an impaired endothelial healing after stenting when comparedwith SES.