A Randomized Trial of Creatine-kinase Leak After Rosuvastatin in Elective Percutaneous Coronary Intervention (CLEAR-PCI).

OBJECTIVES: To determine the impact of percutaneous coronary intervention (PCI) performed at the same time of the peak concentration of rosuvastatin to reduce periprocedural myocardial infarction (PMI). BACKGROUND: Prior studies suggest that a high dose of statin before PCI reduce periprocedural myocardial infarction. However, there is no information regarding the elective PCI performed at the time of the peak of statin concentration to reduce PMI. METHODS: From 2001 to 2013, at a single center in Brazil we enrolled 544 patients who underwent elective PCI and after exclusions for baseline biases in clinical and angiographic characteristics, yielding 528 patients, we prospectively randomly assigned them to either a high loading dose of Rosuvastatin before PCI (n = 264) or standard treatment (n = 264). After exclusions for biases in procedural characteristics a total of 487 patients underwent to end points analysis. The primary outcome was the incidence of MB fraction of creatine kinase (CK-MB) greater than three times the upper limit of normal. RESULTS: The primary end point occurred in 7.6% in the rosuvastatin and 4.8% in the control group (P = 0.200). There was a higher incidence in elevation of CK-MB than normal baseline in the rosuvastatin (67.1% vs 59.2%, P = 0.701). There was no difference in major adverse event (0% in the rosuvastatin group vs 0.8% in control).

Clinical, angiographic, and intravascular ultrasound results of the VestSaync II trial.

AIM: We sought to assess the long term efficacy of the novel VESTAsync™ Eluting Stent (VES) combining a Cro-Co platform with a nanothin-microporous hydroxyapatite surface coating impregnated with a polymer-free low-dose of Sirolimus (55 µg). METHODS: The Vestasync II trial was a randomized (2:1), double-blinded, multicenter comparison of the VES to its platform, the Gen X stent, with microporous hydroxyapatite surface coating without sirolimus. Patients were eligible if they presented de novo lesions in native coronary arteries with 3.0-3.5 mm diameter and ≤ 14 mm in length. Primary endpoint was 8-month in-stent late loss and % of stent obstruction. Lifelong aspirin and 6-month clopidogrel were prescribed to all patients. RESULTS: Seventy-five patients were enrolled (VES = 50 pts). Baseline characteristics included mean age of 58 years and 29% of diabetics. Reference vessel diameter and lesion length were 2.8 ± 0.4 mm and 13.0 ± 2.0 mm, respectively. In-stent late loss (0.39 ± 0.20 vs. 0.74 ± 0.52, P = 0.03) and % of neointima hyperplasia (9.3 ± 6.6% vs. 17.6 ± 9.4%, P = 0.0016) were significantly reduced in the VES cohort. Up to 1 year, there was a single case of myocardial infarction and one target lesion revascularization (TLR) (2%) in the VES group while in the control cohort there were one TLR (4%) and one cardiac death (4%). CONCLUSION: The VestSync II trial is a proof-of-concept study and demonstrates the sustained efficacy of this novel polymer-free sirolimus drug-eluting stents. A larger trial, with more complex lesions, clinical endpoints and longer FU period is warranted. © 2013 Wiley Periodicals, Inc.

Alcohol septal ablation after myomectomy failure solutions for unusual cases.

We report an eight-year-old child presented with classical features of hypertrophic obstructive cardiomyopathy and with New York Heart Association (NYHA) class III symptoms, eight months after myectomy and refractory to medical treatment. Cardiac transplantation was indicated due to the severity of symptoms. But the lymphocyte reaction test showed almost 100% reaction of antibodies, and the surgeons rejected the heart transplantation for fear of hyperacute rejection. Then an alcohol septal ablation (ASA) was proposed, which was successfully performed on August 17, 2005. The post-extrasystolic gradient was reduced from 160 to 60 mm Hg immediately and no other complications were seen. The child is being followed since then and echocardiography changes include a further reduction of septum thickness and gradient (P = 0.001), and important symptoms relieved after 3.5 years of follow up. ASA may be an option to be considered in children with critical hypertrophic obstructive cardiomyopathy in NYHA functional class III/IV, when other methods of treatment failed. © 2010 Wiley-Liss, Inc.

Drug-eluting stents vs bare metal stents for the treatment of large coronary vessels.

BACKGROUND: Lately drug-eluting stents (DES) have dramatically reduced restenosis rates and need for repeat revascularization in a wide subset of lesion and patients. However, their benefit for the treatment of large vessels (> 3.0 mm) has yet to be established. OBJECTIVE: We investigated whether DES are superior to bare metal stents (BMS) in terms of clinical outcomes for the treatment of large coronary vessels. METHODS: This study assessed the long-term outcomes (cardiac death, acute myocardial infarction, and need for repeat intervention in the treated vessel) of patients treated with either a DES (Cypher and Taxus) or a BMS of > or = 3.5 mm in diameter. A total of 250 consecutive patients who underwent DES implantation were clinically followed for 1 year and compared to 250 patients who were treated with BMS. Interventions in the setting of acute ST elevation myocardial infarction and treatment of bypass grafts were excluded. RESULTS: Cypher was the DES deployed in 70.8% of cases. Most of the enrolled patients were men (78%) with single vessel disease (65.6%). The left anterior descending artery was the culprit vessel in 34.2% of cases. Bare metal stent and DES cohorts had equivalent interpolated reference vessel diameter (3.19 +/- 0.3 mm for BMS vs 3.18 +/- 0.2 for DES; P = .1). Lesion was significantly longer in the group treated with DES (13.4 +/- 5.1 mm for BMS group vs 14.3 +/- 3.5 for DES; P = .0018). After 1 year of clinical follow-up, 95.2% of patients treated with DES and 91.2% of the patients who received BMS were free of major events (P = .2). A trend toward higher target-lesion revascularization was noticed in the group treated with BMS (4.8% vs 1.6%; P = .07). CONCLUSION: Percutaneous treatment of large coronary vessels carries a low risk of clinical events irrespective of the type of stent used.

Influence of age and coronary artery disease on homocysteine levels in the young old compared with the old old and the oldest old.

A total of 172 elderly individuals, divided into case and control groups based on the diagnosis of coronary artery disease, underwent coronary angiography to investigate the influence of age and coronary artery disease on homocysteine levels. The subjects were divided into three age ranges: 65-74 years, 75-79 years, and 80 years and older. Continuous homocysteinemia was associated with a risk ratio for coronary artery disease of 1.07 for each micromol/L increase in homocysteine level. Hyperhomocysteinemia (values above 14 micromol/L) constituted an independent risk factor for coronary artery disease, with a risk ratio of 2.03. There was a progression of homocysteine levels between the young old and the oldest old only among the case group elderly. There was no difference among the control group elderly. There were no significant differences in vitamin levels. The rise in homocysteine levels from the young old to the oldest old may be considered not a normal pattern, but rather a pattern associated with coronary artery disease.

[Comparative analysis of intimal hyperplasia after sirolimus-eluting stent and thin-strut bare-metal stent implantation in small coronary arteries]. / Análise comparativa da hiperplasia intimal após o implante de stents com e sem sirolimus em artérias coronárias de pequeno calibre.

OBJECTIVE: This study aimed at evaluating reduction in intimal hyperplasia volume following angioplasty using sirolimus-eluting stents (Cypher) compared with thin-strut bare-metal stents (Pixel) in patients with small vessels. METHODS: Eighty patients with coronary artery disease were prospectively included in two consecutive series, the first using sirolimus-eluting stents (50) and the second using bare-metal stents (30). RESULTS: The use of sirolimus-eluting stents reduced: in-stent net volume obstruction [5.0% (SE = 0.77) x 39.0% (SE = 4.72), p < 0.001], in-stent late loss [0.25 mm (SE = 0.03) x 1,11 mm (SE = 0.13), p < 0.001], in-segment late loss [0.30 mm (SE = 0.04) x 0.83 mm (SE = 0.11), p < 0.001], in-stent restenosis (0% x 33.3%, p < 0.001) and in-segment restenosis (4% x 36.7%, p < 0.001). The event-free survival rate was 96% in the sirolimus-eluting stent group versus 86.7% in the bare-metal stent group (BMS) (p = 0.190). CONCLUSION: Sirolimus-eluting stents are superior to thin-strut bare-metal stents in reducing intimal hyperplasia (less in-stent obstruction and less late lumen loss) in patients with small vessels. The use of these stents significantly reduced angiographic restenosis at eight months.

Percutaneous implantation of endoprostheses in the carotid arteries.

OBJECTIVE: To assess the in-hospital evolution of patients undergoing percutaneous stent placement in the carotid arteries. METHODS: From August 1996 to April 2001, we studied 86 patients with carotid arterial obliterative lesions > 70% who were treated with percutaneous stent placement in the carotid arteries. We assessed the rate of success of the implantation and of the procedure, the types of stents used, mortality rate, and neurological complications. RESULTS: Successful implantation was obtained in 98.9% of the cases, and the procedure was successful in 91.8%. The Wallstent was the most frequently used stent (73 patients - 77%). Cerebral strokes occurred as follows: 3 (3.2%) transient ischemic attacks, 1 (1.1%) minor stroke, and 3 (3.1%) major strokes. One (1.1%) patient died during hospitalization. CONCLUSION: The high rate of success of stent implantation (98.9%) in addition to the low rate of cerebral stroke/death (4.2%) showed the efficiency and safety of percutaneous stent placement in carotid arteries.

Very long-term follow-up of strut apposition and tissue coverage with Biolimus A9 stents analyzed by optical coherence tomography.

First generation drug-eluting stents (DES) are associated with reduced in-stent restenosis but significant increased risk of very late stent thrombosis (VLST). The absence of polymer in DES systems may reduce the occurrence of VLST. Optic coherence tomography (OCT) has been used for stent analysis as a surrogate safety endpoint. This study aimed to assess the long-term follow up of strut apposition and tissue coverage of BioMatrix DES by OCT. 20 patients undergoing BioMatrix DES (n = 15) or S-Stent BMS (n = 5) implantation were followed for at least 5 years and evaluated by quantitative coronary angiography, intravascular ultrasound, and OCT. The difference between the stent types was evaluated by nonparametric Mann-Whitney U test while categorical variables were evaluated by Fisher exact test. Rates of in-stent late loss were similar between groups [0.40 (0.21;0.77) vs. 0.68 (0.66; 0.82) mm, p = 0.205, for BioMatrix and S-Stent, respectively]. The vessel, stent and lumen volumes did not differ between groups. Patients treated with BioMatrix had significantly less stent obstruction [5.6 (4.4;9.7) vs. 28.6 (24.7;29.0) %, p = 0.001]. OCT analysis of 12 stents (Biomatrix = 9 and S-Stent = 3) demonstrated 126 (8.7 %) uncovered struts in the BioMatrix group compared to 23 (4.0 %) in the S-Stent group (p = 0.297), being the majority of them well apposed (117/126 and 21/23, respectively, p = 0.292). Only 9 (0.6 %) struts in the DES and 2 (0.4 %) struts in the BMS groups were simultaneously uncovered and malapposed (p = 0.924). BioMatrix DES was associated with lower rates of in-stent obstruction, and similar percentage of neointimal coverage on struts and of complete strut apposition.

Cardiovascular effects of local anesthesia with vasoconstrictor during dental extraction in coronary patients.

OBJECTIVE: To evaluate the occurrence of variables detecting myocardial ischemia during or after dental treatment under anesthesia with vasoconstrictor (epinephrine). METHODS: A total of 54 coronary patients undergoing dental extraction under local anesthesia with or without vasoconstrictor were included. They were divided into two groups (by drawing envelopes): group I (27 patients) using anesthetics with vasoconstrictor, and group II (27 cases) without vasoconstrictor. 24-hour Holter monitoring, Doppler-echocardiogram before and after dental intervention, and determination of biochemical markers (CK-MB mass, CK-MB activity, and troponin T) before and 24 hours after dental extraction were performed in all patients. Heart rate and blood pressure were also measured in the pre, post-anesthesia and post-dental extraction phases. Doppler echocardiography assessed left ventricular segmental contractility and the occasional occurrence of mitral regurgitation. The usual pharmaceutical treatment prescribed by the cardiologist was maintained in all cases. RESULTS: Three patients in group I presented ST-segment depression (1.0 mm) during administration of anesthesia; two other patients in group I had CK-MB mass elevation, and ischemia was not observed in any other case, as assessed by the other methods. No chest pain, arrhythmias, occurrence or worsening of left ventricular segmental hypocontractility or mitral regurgitation were observed in the study. CONCLUSION: Dental extraction performed under anesthesia with 1:100,000 epinephrine does not imply additional ischemic risks, as long as performed with good anesthetic technique and maintenance of the pharmacological treatment prescribed by the cardiologist.

Late incomplete apposition after drug-eluting stent implantation: incidence and potential for adverse clinical outcomes.

AIM: Late-acquired incomplete stent apposition (ISA) has been documented after drug-eluting stent (DES) implantation; however, its clinical role remains controversial. We sought to investigate the incidence and long-term clinical consequences of late ISA after implantation of sirolimus- (SES) or paclitaxel-eluting stent (PES) in a non-selected population. METHODS AND RESULTS: From our database, we analysed 195 consecutive patients who underwent DES placement (175 with SES and 20 with PES) into native artery lesions and had serial intravascular ultrasound studies (IVUS) performed at index procedure and after 6-8 months. They were clinically followed for 29 +/- 15 months (median of 24.3 months, interquartile range 18.1-31.6 months). Late ISA was defined as separation of at least one stent strut from the vessel wall in a segment without a side-branch and where the immediate post-implantation IVUS revealed complete apposition of stent struts. We identified 10 patients (5.1%) with late ISA, three patients after PES, and seven patients after SES implantation. ISA was localized almost exclusively at body of the stents (nine out of 10 cases). Mean ISA volume and length were 44.5 +/- 41.9 mm(3) and 7.4 +/- 11 mm, respectively. There was a marked increase in vessel volume from 416.0 +/- 163.9 mm(3) at baseline to 514.4 +/- 247.9 mm(3) at follow-up (P = 0.001) with no significant change in plaque volume (232.4 +/- 52.7 at baseline and 226.4 +/- 22.3 mm(3) at follow-up, P = 0.3) in patients who presented with late-acquired ISA. During the follow-up period, one patient with SES and one patient with PES who presented late-acquired ISA had late stent thrombosis and acute myocardial infarction. CONCLUSION: Late-acquired ISA was observed in 5.1% of patients after DES implantation and is related to regional vessel positive remodelling. The relationship between late-acquired ISA and long-term adverse outcomes (e.g. stent thrombosis) requires further analysis.

Late outcome of sirolimus-eluting stents: comparison of multidetector computed tomography with quantitative coronary angiography and intravascular ultrasound.

OBJECTIVE: To assess the performance of multidetector computed tomography in determining late clinical outcomes of patients undergoing sirolimus-eluting stent implantation. METHODS: Thirty patients, successfully submitted to sirolimus-eluting stent implantation for more than six months, were selected to participate in the study. All underwent invasive angiography and intravascular ultrasound following CT angiography using iodinated contrast medium at a dose of 1.5 ml/kg. RESULTS: Mean proximal reference diameter was 3.01 +/- 0.31 mm by tomography and 3.14 +/- 0.31 mm by angiography (p = 0.04). When the left circumflex artery was excluded from the analysis, the difference between both examinations was no longer significant (tomography = 3.01 +/- 0.32 mm; angiography = 3.10 +/- 0.30 mm, p = 0.65). Mean distal reference diameter was 2.86 +/- 0.30 mm by tomography and 2.92 +/- 0.32 by angiography (p = 0.25). Mean in-stent minimal lumen diameter was 2.85 +/- 0.25 mm by tomography and 2.85 +/- 0.29 mm by angiography (p = 0.27). Mean minimal in-stent cross-sectional area was 7.19 +/- 1.47 mm(2) by tomography and 6.90 +/- 1.52 mm(2) by intravascular ultrasound (p = 0.36), but there was only a weak correlation between these measurements (r = 0.33). CONCLUSION: Computed tomography allows the qualitative assessment of sirolimus-eluting stents, accurate estimate of proximal and distal reference diameters of the target vessel, and in-stent minimal lumen diameter. Its correlation with measurements performed using intravascular ultrasound, however, is less strong.

Double balloon pulmonary valvuloplasty: multi-track system versus conventional technique.

OBJECTIVES: To evaluate whether double balloon pulmonary valvuloplasty (DBPV) with the Multi-Track system (MTS) may help to simplify the procedure. BACKGROUND: DBPV is usually required for patients with pulmonary valve stenosis with large annulus. However, it needs two venous accesses and can be technically demanding. METHODS: From 07/03, 20 consecutive patients (19 +/- 10 yrs) with typical pulmonary valve stenosis underwent DBPV using the MTS (G1). The results were compared with those achieved by conventional DBPV performed in a matched historical group of 28 patients (21 +/- 11 yrs; P = NS) (G2). RESULTS: MTS balloons were easily advanced through the skin and inflated across the valve. Similar results were observed in regards to residual gradients (12 +/- 11 vs 14 +/- 10 mm Hg; P = NS) and right ventricular to systemic pressures (0.35 +/- 0.22 vs 0.37 +/- 0.26; P = NS). Procedure and fluoroscopic times were significant lower in G1 (78 +/- 24 vs 126 +/- 28; 15 +/- 12 vs 25 +/- 8 min, respectively; both P < 0.001). There was no major complication. Median follow-up was 1.8 yr for G1 and 5 yr for G2 (P = 0.037). At the last visit, peak instantaneous gradient across the right ventricular outflow tract by echocardiography was a mean 22 +/- 10 mm Hg for G1 and 25 +/- 9 mm Hg for G2 (P = NS). No patient had severe pulmonary insufficiency or required reintervention. CONCLUSIONS: The use of the MTS helped to expedite the procedure providing satisfactory midterm clinical outcomes, similar to those observed with the conventional DBPV technique.

Stenting vs. balloon angioplasty for discrete unoperated coarctation of the aorta in adolescents and adults.

More information is needed to clarify whether stenting is superior to balloon angioplasty (BA) for unoperated coarctation of the aorta (CoA). From September 1997, 21 consecutive adolescents and adults (24 +/- 11 years) with discrete CoA underwent stenting (G1). The results were compared to those achieved by BA performed in historical group of 15 patients (18 +/- 10 years; P = 0.103; G2). After the procedure, systolic gradient reduction was higher (99% +/- 2% vs. 87% +/- 17%; P = 0.015), residual gradients lower (0.4 +/- 1.4 vs. 5.9 +/- 7.9 mm Hg; P = 0.019), gain at the CoA site higher (333% +/- 172% vs. 190% +/- 104%; P = 0.007), and CoA diameter larger (16.9 +/- 2.9 vs. 12.9 +/- 3.2 mm; P < 0.001) in G1. Aortic wall abnormalities were found in eight patients in G2 (53%) and in one in G1 (7%; P < 0.001). There was no major complication. Repeat catheterization (n = 33) and/or MRI (n = 2) was performed at a median follow-up of 1.0 year for G1 and 1.5 for G2 (P = 0.005). Gradient reduction persisted in both groups, although higher late gradients were seen in G2 (median of 0 mm Hg for G1 vs. 3 for G2; P = 0.014). CoA diameter showed no late loss in G1 and a late gain in G2 with a trend to being larger in G1 (16.7 +/- 2.9 vs. 14.6 +/- 3.9 mm; P = 0.075). Two patients required late stenting due to aneurysm formation or stent fracture in G1. Aortic wall abnormalities did not progress and one patient required redilation in G2. Blood pressure was similar in both groups at follow-up (126 +/- 12/81 +/- 11 for G1 vs. 120 +/- 15/80 +/- 10 mm Hg for G2; P = 0.149 and 0.975, respectively). Although satisfactory and similar clinical outcomes were observed with both techniques, stenting was a better means to relieve the stenosis and minimize the risk of developing immediate aortic wall abnormalities.

Evolução tardia após intervenção coronária percutânea com stents farmacológicos em pacientes diabéticos do Registro DESIRE (Drug-Eluting Stents in the Real World) / Long-Term results after percutaneous coronary intervention with drug eluting stents in diabetic patients in the DESIRE (Drug-Eluting Stents in the Real World)

Fundamentos: O diabetes melito está relacionado à ocorrência de desfechos desfavoráveis após intervenções coronárias percutâneas. Os stents farmacológicos podem conferir melhor evolução tardia a esse subgrupo de pacientes. O objetivo deste estudo foi avaliar o desempenho desses instrumentais em pacientes diabéticos. Métodos: O DESIRE é um registro unicêntrico, prospectivo, que inclui 2,365 pacientes tratados consecutivamente com stents farmacológicos, entre maio de 2002 e janeiro de 2008. Para a presente análise foram excluídos pacientes com diagnóstico de infarto do miocárdio, aqueles com lesão tratada em ponte de safena e os com período de evolução inferior a 6 meses. Resultados: Assim 1.705 pacientes foram divididos em dois grupos: não-diabéticos (n igual 1.211 pacientes, 71,1 por cento) e diabéticos (n igual 494 pacientes, 28,9 por cento),sendo 109 (6,4 por cento) pacientes em uso de insulina. Dentre os diabéticos havia mais idosos (64,8 mais ou menos 9,8 anos vs. 63,4 mais ou menos11,7 anos; p igual 0,025), mulheres (28,9 por cento vs. 22,5 por cento; p igual 0,005), obesos (35,2 por cento vs. 23,5 por cento; p menor 0,001)...

Background: Diabetes mellitus is related to the occurrence of unfavorable outcomes after percutaneous coronary interventions. Drug-eluting stents can confer a better late evolution to this subgroup. The aim of this study was to assess the performance of these devices in diabetic patients. Methods: The DESIRE is a single-center, prospective registry that included 2,365 consecutive patients treated with drug-eluting stents between May 2002 and January 2008. For the present analysis, patients with a diagnosis of acute myocardial infarction, those with saphenous vein grafts lesions and those within 6 months of the index procedure, were excluded. Results: Therefore, 1,705 patients were divided into two groups: non-diabetics (n = 1,211 P/71.1%) and diabetics (n = 494 P/28.9%), of which 109 P (6.4%) were insulin-dependent. Among the diabetics there was a higher number of older people (64.8 ± 9.8 years old vs. 63.4 ± 11.7 years old; p = 0.025), females (28.9 vs. 22.5%; p = 0.005), patients with obesity (35.2 vs. 23.5%; p < 0.001), hypertension (86.6 vs. 73.7%; p < 0.001), multi-vessel disease (63.4 vs. 54.4%; p = 0.001), small-vessel disease (2.70 ± 0.51 mm vs. 2.75 ± 0.42 mm; p < 0.001) and calcified lesions (32.3 vs. 27.1%; p = 0.009).In the late clinical follow up (2.2 ± 1.1 years), the combined cardiac events occurred more frequently in the diabetic patients (9.8 vs. 7.0%; p = 0.048). The multivariate analysis showed that diabetes mellitus (OR = 1.45; 95% confidence interval 1.0 to 2.1) and the presence of a calcified lesion

Resposta coronária às intervenções intravasculares / Coronary response intravascular interventions

O uso de instrumentais percutâneos par tratamento de obstruções no leito coronariano promove algum grau de dano vascular. A resposta do endotélio a essa agressão possui várias etapas, podendo ocorrer em diferentes proporções, desde o modelo considerado fisiológico de reparo vascular até as formas mais extremas representadas pela resposta neointimal exarcebada ou deficiente que parecem estar relacionadas com duas das principais...

Efeito anti-hipertensivo de urapidil em hipertensäo arterial leve a moderada: estudo randomizado, duplo-cego, contra placebo / Antihypertensive effect of urapidil in mild to moderate arterial hypertension: randomized, double-blind versus placebo study

PURPOSE--To evaluate the efficacy and tolerability of urapidil (a new central and peripheral antihypertensive agent) in patients with mild to moderate essential hypertension. METHODS--Thirty-one patients were randomized, double-blindly, to receive either placebo (15 patients) or urapidil (16 patients) for 3 months. The initial dose of urapidil was 30mg twice daily, per oral. The dose was increased progressively till achievement of good blood pressure control or the dose of 60mg three times a day. RESULTS--Seventy percent of the patients on urapidil group responded to therapy against 30 per cent on the placebo group. There were 3 cases of hypertensive crises (2 on urapidil and 1 on placebo) on the early therapy. The adverse events with urapidil were unfrequent and the most common were headache and dizziness. There were no modification on blood sugar and lipids level. CONCLUSION--Urapidil appears to be a safe antihypertensive agent in the treatment of mild to moderate essential hypertension. It also did not demonstrate any clinical effect on the carbohydrates and lipids profile

Estudo comparativo das características fluidodinâmicas de próteses valvulares biológicas de pericárdio bovino de perfil alto e baixo / Comparative study of fluid dynamics characteristics of biological valve prosthesis from bovine pericardium of high and low profiles

O comportamento fluidodinâmico e a vida útil média de uma prótese vaivular cardíaca sao características muito importantes na escolha do modelo de prótese a ser implantada em um determinado paciente. Por esse motivo, foi realizado um estudo comparativo entre as válvulas biológicas de perfil alto e baixo, para se verificarem possíveis alteraçoes na vida média, gradiente de pressao e refluxo, causadas pela diminuiçao do perfil dessas próteses. Com o auxilio de um duplicador de pulso, foram analisadas cinco próteses de perfil alto e cinco de perfil baixo, todas tamanho 29, fabricadas no Instituto Dante Pazzanese de Cardiologia (IDPC). Mantendo-se a freqüência de batimentos em 100 bpm e a diferença de pressao em 1000 mmHg, verificou-se que a vida útil média da válvula de perfil baixo permaneceu equivalente à de perfil alto. Em outro equipamento, denominado simulador cardíaco, as próteses foram submetidas a condiçoes semelhantes às condiçoes fisiológicas de funcionamento para uma freqüência cardíaca de 75 bpm. Os resultados mostraram que o volume de retorno necessário para fechamento (refluxo), nas válvulas de perfil baixo, é menor do que nas de perfil alto. Isso traz um melhor aproveitamento do efeito de bombeamento do coraçao. As perdas de carga das válvulas foram comparadas através dos gradientes máximos de pressao visibilizados com a sobreposiçao dos sinais de pressao. Observou-se que as válvulas de perfil baixo oferecem menos resistência ao fluxo; assim, quando sao implantadas, possibilitam uma passagem mais livre e desobstruída do sangue.