RESUMO
Tricuspid regurgitation is serious disease for which surgical correction is underperformed because of a prohibitive risk. It is responsible for a 50% mortality at 3 years which is decreased by surgical treatment. However, only a negligible proportion of patients undergoes surgery. In this context, there is currently an unmet need for percutaneous treatment technique. Several technologies are undergoing preclinical or early clinical development. These techniques aim to mimic the different surgical strategies used for the treatment of tricuspid regurgitation. Thus, some target the leaflets, the tricuspid annulus or offer a complete tricuspid valve replacement. Before planning a transcatheter tricuspid intervention, a comprehensive evaluation is mandatory, addressing the patient clinical status and comorbidities, the tricuspid regurgitation ad its consequences on right heart and, the anatomy of the tricuspid annulus and the right heart to determine if the patient is eligible for the chosen technique. This article will review the indications, contraindications and exams to perform before transcatheter tricuspid intervention and will then detail the different strategies available or undergoing development.
Assuntos
Implante de Prótese de Valva Cardíaca/métodos , Próteses Valvulares Cardíacas , Insuficiência da Valva Tricúspide/cirurgia , Valva Tricúspide/cirurgia , Cateterismo Cardíaco/métodos , Humanos , Ilustração Médica , Seleção de Pacientes , Desenho de Prótese , Instrumentos Cirúrgicos , Técnicas de Sutura , Valva Tricúspide/diagnóstico por imagem , Insuficiência da Valva Tricúspide/diagnóstico por imagemRESUMO
Coronary artery disease (CAD) is an emerging complication in HIV-infected patients treated with highly active antiretroviral therapy. Immediate results and long-term outcome after coronary artery bypass graft (CABG) have not been yet evaluated in this population. Between January 1997 and December 2005, we compared baseline characteristics, immediate results and clinical outcome [Major Adverse Cardiac Events (MACE): death for cardiac cause, myocardial infarction (MI), coronary revascularization] at 41 months in 27 consecutive HIV-infected (HIV+) patients and 54 HIV-uninfected (HIV-) controls matched for age and gender (mean age of the cohort, 49+/-8 years; 96% male) who underwent CABG. Cardiovascular risk factors were well-balanced and nearly identical in both groups. In HIV+ group, mean preoperative CD4 was 502+/-192/mm(3) compared with 426.2+/-152.6/mm(3) postoperatively (p=0.004) without clinical manifestations at follow-up. At 30-day, the rate of post-operative death, MI, stroke, mediastinitis, re-intervention was identical in both groups. At follow-up [median: 41-months (range: 34-60)], rate of occurrence of 1(st) MACE was higher in HIV+ group compared with HIV- group (11, 42% versus 13, 25%, p=0.03), mostly due to the need of repeated revascularization using percutaneous coronary intervention of the native coronary arteries but not of the grafts in the HIV+ group [9 (35%) versus 6 (11%), p=0.02]. CABG is a feasible and safe revascularization procedure in HIV+ patients with multivessel CAD. Immediate postoperative outcome was similar compared to controls. However, long-term follow-up was significantly different, due to an increased rate of repeated revascularization procedure in the native coronary arteries of HIV+ patients.
Assuntos
Angioplastia Coronária com Balão , Ponte de Artéria Coronária/efeitos adversos , Doença da Artéria Coronariana/cirurgia , Infecções por HIV/complicações , Adulto , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Estudos de Casos e Controles , Ponte de Artéria Coronária/reabilitação , Doença da Artéria Coronariana/induzido quimicamente , Doença da Artéria Coronariana/complicações , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos RetrospectivosRESUMO
Mechanical cardiac support represents a large spectrum of devices. The duration of assistance may vary from a few hours in the cath lab to several weeks. The goals for a temporary support by percutaneus assistance are: improve end-organ perfusion; decrease pulmonary capillary wedge pressure; decrease myocardial oxygen consumption. The potential indications are: acute left ventricular dysfunction; "bridge to recovery": acute myocarditis, acute myocardial infarction, valve disease bridge to surgery; "bridge to implantable LVAD"; "bridge to transplant"; high risk PCI and surgery.
Assuntos
Circulação Assistida/instrumentação , Coração Auxiliar , Angioplastia Coronária com Balão , Cateterismo Cardíaco , Oxigenação por Membrana Extracorpórea , Transplante de Coração , Doenças das Valvas Cardíacas/terapia , Humanos , Balão Intra-Aórtico , Laboratórios Hospitalares , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/terapia , Miocardite/terapia , Miocárdio/metabolismo , Consumo de Oxigênio/fisiologia , Pressão Propulsora Pulmonar/fisiologia , Choque Cardiogênico/terapia , Disfunção Ventricular Esquerda/terapiaRESUMO
Atrial natriuretic peptide (ANP) exhibits relaxant and growth-inhibiting effects on vascular smooth muscle cells (VSMCs). To obtain ANP gene expression in VSMCs, we built a recombinant adenovirus containing the ANP cDNA controlled by the adenovirus major late promotor (AdMLP-ANP). After pulmonary VSMC treatment with AdMLP-ANP at a multiplicity of infection ranging from 5 to 100 TCID(50)/cell, immunoreactive ANP was detectable in the cell culture medium at a level that reached 101 +/- 27 pmol/well after 2 days. The newly expressed ANP was biologically active, as evidenced by its ability to induce cyclic guanosine monophosphate accumulation in target cells and to mimic the effect of exogenous ANP (10(-8) to 10(-7) mol/L). Cell growth and survival of AdMLP-ANP-infected cells were decreased and were associated with the promotion of VSMC apoptosis. These effects, which occurred at a multiplicity of infection of 10 to 100 TCID(50)/cell, were observed neither in cells infected with the control adenoviral constructs (AdMLP-betaGAL and AdMLP-gD) nor in cells treated with exogenous ANP (10(-7) to 10(-6) mol/L). These results showing VSMC apoptosis in response to ANP gene expression may have important implications for the prevention of vascular remodeling by gene therapy.
Assuntos
Adenoviridae/genética , Apoptose/fisiologia , Fator Natriurético Atrial/genética , Vetores Genéticos , Músculo Liso Vascular/citologia , Animais , Divisão Celular/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , DNA Recombinante , Músculo Liso Vascular/fisiologia , Artéria Pulmonar/citologia , RatosRESUMO
Focal vascular injury and impaired endothelial function are features of pulmonary hypertension (PH) that lead to enhanced platelet endothelial cell interactions. Vascular endothelial growth factor (VEGF) is contained in platelets and released at sites of vascular injury to promote endothelial repair and wound healing in combination with platelet-derived nonspecific mitogens such as platelet-derived growth factor (PDGF). The overall balance between platelet VEGF and PDGF was investigated in 21 patients with primary PH, 8 with secondary PH, and 27 with chronic hypoxemic lung disease (CHLD), as well as in 29 control subjects. Platelet VEGF content was increased in patients with primary and secondary PH as compared with control subjects (518 +/- 89, 675 +/- 156, and 166 +/- 29 fg/10(5) platelets, respectively; p < 0.01), whereas platelet PDGF content was similar in the three groups (31 +/- 2, 36 +/- 4, and 33 +/- 3 pg/10(5) platelets, respectively; NS). Patients treated with a continuous prostacyclin infusion had a higher platelet VEGF but a similar platelet PDGF content as compared with untreated patients. Moderate increases in platelet VEGF and PDGF contents were observed in the CHLD patients. We conclude that patients with primary or secondary PH have an increase in platelet VEGF content, but not in platelet PDGF content, and that their platelet VEGF content increases further in response to prostacyclin infusion. We suggest that imbalance between platelet VEGF and PDGF is beneficial to patients with PH.
Assuntos
Plaquetas/efeitos dos fármacos , Fatores de Crescimento Endotelial/sangue , Epoprostenol/uso terapêutico , Hipertensão Pulmonar/tratamento farmacológico , Linfocinas/sangue , Fator de Crescimento Derivado de Plaquetas/metabolismo , Adolescente , Adulto , Idoso , Plaquetas/metabolismo , Feminino , Humanos , Hipertensão Pulmonar/sangue , Infusões Intravenosas , Pneumopatias/sangue , Pneumopatias/tratamento farmacológico , Pneumopatias Obstrutivas/sangue , Pneumopatias Obstrutivas/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
OBJECTIVES: We sought to evaluate dobutamine stress echocardiography (DSE) for predicting recovery of viable myocardium after revascularization with cineangiography as a gold standard for left ventricular (LV) function. We studied the influence of late vessel reocclusion on regional LV function. BACKGROUND: Dobutamine stress echocardiography is a well established evaluation method for myocardial viability assessment. In previous studies the reference method for assessing LV recovery was echocardiography, long-term vessel patency has not been systematically addressed. METHODS: Sixty-eight patients with a first acute myocardial infarction (AMI) and residual stenosis of the infarct related artery (IRA) underwent DSE (mean +/- standard deviation) 21 +/- 12 days after AMI to evaluate myocardial viability. Revascularization of the IRA was performed in 54 patients by angioplasty (n = 43) or bypass grafting (n = 11). Coronary angiography and LV cineangiography were repeated at four months to assess LV function and IRA patency. RESULTS: Sensitivity and specificity of DSE for predicting myocardial recovery after revascularization were 83% and 82%. In the case of late IRA patency, specificity increased to 95%, whereas sensitivity remained unchanged. In the 16 patients with myocardial viability and late IRA patency, echocardiographic wall motion score index decreased after revascularization from 1.83 +/- 0.15 to 1.36 +/- 0.17 (p = 0.0001), and left ventricular ejection fraction (LVEF) increased from 0.52 +/- 0.06 to 0.57 +/- 0.06 (p = 0.0004), whereas in five patients, reocclusion of the IRA prevented improvement of segmental or global LV function despite initially viable myocardium. CONCLUSIONS: Dobutamine stress echocardiography is reliable to predict recovery of viable myocardium after revascularization in postinfarction patients. Late reocclusion of the IRA may prevent LV recovery and influence the accuracy of DSE.
Assuntos
Angioplastia Coronária com Balão , Ponte de Artéria Coronária , Contração Miocárdica/fisiologia , Infarto do Miocárdio/terapia , Função Ventricular Esquerda/fisiologia , Adulto , Idoso , Cardiotônicos , Cineangiografia , Angiografia Coronária , Dobutamina , Ecocardiografia , Teste de Esforço , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/fisiopatologia , Variações Dependentes do Observador , Sensibilidade e Especificidade , Sobrevivência de Tecidos/fisiologiaRESUMO
The coronary circulation has a protective regulation system which, in extreme haemodynamic conditions, compensates increased myocardial oxygen demand. The coronary reserve, based on this concept defines the capacity of the system to increase flow temporally, and, thereby, myocardial oxygen supply. The introduction of new methods of investigating the coronary microcirculation has enabled the study of this phenomenon in several cardiovascular pathologies. Two types of investigation are used currently for studying the coronary microcirculation: 1) invasive methods, especially the recently developed intracoronary Doppler and pressure guide, 2) non-invasive methods, and, in particular, contrast echocardiography, position emission tomography and magnetic nuclear resonance. These investigations allow measurement of the coronary reserve or the assessment of the myocardial consequences of abnormalities of the microcirculation. Some workers use these methods to investigate pathological coronary microcirculation in different cardiomyopathies, in the presence of different cardiovascular risk factors (hypertension, diabetes, smoking, hypercholesterolaemia) and after cardiac transplantation.
Assuntos
Circulação Coronária/fisiologia , Microcirculação/fisiologia , HumanosRESUMO
Percutaneous transluminal angioplasty continues to be limited by restenosis. Prevention of restenosis is now focusing on local delivery of therapeutic agents, such as proliferation-inhibiting genes, directly to the site of arterial injury. We evaluated use of the Infiltrator catheter (IVT, San Diego, CA. U.S.A.) for gene delivery within the arterial media. The goals of our study were to evaluate the histologic effects of the injection and the suitability of the Infiltrator catheter for local delivery of viral therapy. We injected the femoral arteries of 21 New Zealand White rabbits. Six animals were used for an evaluation of the intramural distribution of dextran/rhodamine injected via the Infiltrator catheter. In seven animals, injection site histology and in vitro vasoreactivity were studied after an injection of saline. In the remaining eight animals, a replication-deficient adenovirus encoding for the firefly luciferase gene (Ad RSVLuc) was injected, and luciferase activity was quantified 3 and 8 days later. After injection via the Infiltrator catheter, the fluorescent tracer was distributed throughout the entire circumference and width of the arteries. Histologic examination showed minimal damage with partial endothelial abrasion and disruption of the internal elastic lamina confined to the penetration sites. In vitro endothelium-dependent vasodilation was present at a reduced level after injection via the Infiltrator (maximal endothelium-dependent acetylcholine-induced relaxation, 51.5 +/- 7.4% vs. 23.8 +/- 14.6%; p < 0.05). Significant luciferase expression was found in all the arteries, with a significant increase from day 3 to day 8 (5,392.5 +/- 2,300 vs. 2,012 +/- 471 cpm/mg; p < 0.05). These data obtained in a rabbit iliac artery model show that the Infiltrator catheter is an efficient and safe local intramural delivery device that provides significant transgene expression in the arterial wall without causing significant structural damage.
Assuntos
Angioplastia Coronária com Balão/instrumentação , Técnicas de Transferência de Genes , Artéria Ilíaca/patologia , Adenoviridae/genética , Animais , Dextranos , Corantes Fluorescentes , Artéria Ilíaca/enzimologia , Luciferases/metabolismo , Masculino , Coelhos , RodaminasRESUMO
Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen that is upregulated during exposure to hypoxia. In this study, we analyzed heart and lung VEGF mRNA expression and examined pulmonary vascular remodeling as well as myocardial capillary density in two rat models of pulmonary hypertension involving exposure to chronic hypoxia (CH) and treatment with monocrotaline (MCT), respectively. The rats were studied after 0.5, 1, 3, 15, and 30 days of exposure to 10% O2 or 1, 6, and 30 days after a subcutaneous MCT injection (60 mg/kg). Both CH and MCT induced pulmonary hypertension and hypertrophy of the right ventricle (RV) with increased RV weight and atrial natriuretic peptide mRNA expression. VEGF mRNA expression as assessed by Northern blot analysis was potently induced after 12 h of hypoxia in both the right and left ventricles. After prolonged exposure to hypoxia, VEGF mRNA returned to baseline in the left ventricle (LV) but remained increased in the RV, where it peaked after 30 days. In MCT rats, VEGF mRNA was unchanged in the LV but decreased by 50% in the RV and by 90% in the lungs after 30 days. VEGF mRNA remained unchanged in the lungs from CH rats. Pulmonary vascular remodeling was more pronounced in MCT than in CH rats. The number of capillaries per RV myocyte was increased in rats exposed to 30 days of hypoxia, whereas it remained unchanged in MCT rats despite a similar degree of RV hypertrophy. Our results suggest that the sustained increase in VEGF expression in the hypertrophied RV during CH may account for the increased number of capillaries per myocyte. In contrast, reduced VEGF expression in the lungs and RV of MCT rats may aggravate pulmonary vascular remodeling and compromise RV myocardial perfusion.
Assuntos
Fatores de Crescimento Endotelial/genética , Hipertensão Pulmonar/metabolismo , Pulmão/metabolismo , Linfocinas/genética , Miocárdio/metabolismo , Animais , Doença Crônica , Hemodinâmica/fisiologia , Hipertensão Pulmonar/induzido quimicamente , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/fisiopatologia , Hipóxia/complicações , Pulmão/patologia , Masculino , Monocrotalina , Miocárdio/patologia , Tamanho do Órgão/fisiologia , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularAssuntos
Fatores de Crescimento Endotelial/genética , Hipóxia/fisiopatologia , Pulmão/metabolismo , Linfocinas/genética , Miocárdio/metabolismo , Animais , Doença Crônica , Expressão Gênica/efeitos dos fármacos , Monocrotalina/farmacologia , RNA Mensageiro/metabolismo , Ratos , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
To investigate whether polycythemia associated with chronic hypoxemic lung disease (CHLD) increases vascular resistance by altering endothelium-derived nitric oxide (NO), we examined the responses to acetylcholine (ACh) infusions (5, 10, and 15 mg/min) on hemodynamics and gas exchange in 21 patients with CHLD of varying severity. Patients were classified into two groups based on whether their hemoglobin (Hb) level was less or greater than 15.5 g/dl. In the normocythemic patients (Hb = 13.6 +/- 0.3 g/100 ml, n = 10), ACh decreased pulmonary artery pressure (Ppa) from 30 +/- 2 mm Hg 26 +/- 2 mm Hg (p < 0.01); pulmonary vascular resistance (PVR), from 5.1 +/- 0.4 U/m2 to 3.4 +/- 0.3 U/m2 (p < 0.001); systemic arterial pressure (Psa), from 111 +/- 4 mm Hg to 108 +/- 4 mm Hg (p < 0.05); and systemic vascular resistance (SVR), from 27 +/- 2 U/m2 to 22 +/- 2 U/m2 (p < 0.01); and also increased the cardiac index (CI), from 3.8 +/- 0.2 to 4.7 +/- 0.3 L/min/m2 (p < 0.001). PaO2 fell from 59 +/- 3 mm Hg to 48 +/- 3 mm Hg (p < 0.001) whereas venous admixture (Qs/Qt) rose from 32 +/- 4% to 44 +/- 4% (p < 0.01). In contrast, in patients with polycythemia (17.7 +/- 0.5 g/100 ml, n = 11) ACh failed to produce any changes in PaO2 (49 +/- 2 mm Hg versus 51 +/- 2 mm Hg, p = NS), Ppa (34 +/- 1 mm Hg versus 33 +/- 1 mm Hg, p = NS), PVR (6.7 +/- 0.9 U/m2 versus 6.9 +/- 0.8 U/m2, p = NS) or Psa, but slightly increased the CI, from 3.6 +/- 0.3 L/min/m2 to 3.9 +/- 0.3 L/min/m2 (p < 0.01), and Qs/Qt, from 40 +/- 4% to 45 +/- 3% (p < 0.05). In the 21 patients, negative correlations with Hb concentrations were found for ACh-induced changes in PVR (r = -0.57, p < 0.01), Ppa (r = -0.46, p < 0.01), CI (r = -0.5, p < 0.05), PaO2 (r = -0.79, p < 0.01), and Qs/Qt (r = -0.79, p < 0.01). In the six polycythemic patients who received isovolemic hemodilution, with a decrease in Hb concentration from 18.6 +/- 0.9 g/dl to 15.3 +/- 0.3 g/dl as a result, infusion of ACh, which was without effect before hemodilution, caused decreases in Ppa from 28 +/- 1 mm Hg to 23 +/- 1 mm Hg (p < 0.05) and in PVR from 5.7 +/- 0.8 U/m2 to 3.6 +/- 0.5 U/m2 (p < 0.02), as well as an increase in CI from 3.4 +/- 0.4 L/min/ m2 to 4.1 +/- 0.4 L/min/m2 (p < 0.05). In contrast to ACh, inhaled NO (40 ppm) induced pulmonary vasodilation in both the normocythemic and polycythemic groups. Our results show that high hematocrit (Hct) levels inhibit endothelium-dependent vasodilation in response to ACh in patients with CHLD, possibly through inactivation of endothelial-derived NO by Hb.
Assuntos
Acetilcolina/farmacologia , Hipóxia/etiologia , Pneumopatias Obstrutivas/fisiopatologia , Policitemia/fisiopatologia , Circulação Pulmonar/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Acetilcolina/administração & dosagem , Administração por Inalação , Adulto , Idoso , Pressão Sanguínea/efeitos dos fármacos , Débito Cardíaco/efeitos dos fármacos , Relação Dose-Resposta a Droga , Hemodiluição , Hemoglobinas/análise , Humanos , Infusões Intravenosas , Pneumopatias Obstrutivas/sangue , Pneumopatias Obstrutivas/complicações , Pessoa de Meia-Idade , Óxido Nítrico/administração & dosagem , Óxido Nítrico/farmacologia , Óxido Nítrico/fisiologia , Oxigênio/sangue , Policitemia/etiologia , Policitemia/terapia , Troca Gasosa Pulmonar/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacosRESUMO
OBJECTIVES: This study sought to examine the mechanism of increasing coronary flow reserve after balloon angioplasty and stenting. BACKGROUND: Coronary vasodilatory reserve (CVR) does not improve after percutaneous transluminal coronary angioplasty in > or = 50% of patients, postulated to be due to impaired microvascular circulation or inadequate lumen expansion despite adequate angiographic results. METHODS: To demonstrate the role of coronary lumen expansion, serial coronary flow velocity (0.014-in. Doppler guide wire) was measured in 42 patients before and after balloon angioplasty and again after stent placement. A subset (n = 17) also underwent intravascular ultrasound (IVUS) imaging of the target sites after angioplasty and stenting. CVR (velocity) was computed as the ratio of adenosine-induced maximal hyperemic to basal average peak velocity. RESULTS: The percent diameter stenosis decreased from (mean +/- SD) 84 +/- 13% to 37 +/- 18% after angioplasty and to 8 +/- 8% after stenting (both p < 0.05). CVR was minimally changed from 1.70 +/- 0.79 at baseline to 1.89 +/- 0.56 (p = NS) after angioplasty but increased to 2.49 +/- 0.68 after stent placement (p < 0.01 vs. before and after angioplasty). IVUS lumen cross-sectional area was significantly larger after stenting than after angioplasty (8.39 +/- 2.09 vs. 5.10 +/- 2.03 mm2, p < 0.05). Anatomic variables were related to increasing coronary flow velocity reserve (CVR vs. IVUS lumen area: r = 0.47, p < 0.005; CVR vs. quantitative coronary angiographic percent area stenosis: r = 0.58, p < 0.0001). CONCLUSIONS: In most cases, increases in CVR were associated with increases in coronary lumen cross-sectional area. These data suggest that impaired CVR after angioplasty is often related to the degree of residual narrowing, which at times may not be appreciated by angiography. A physiologically complemented approach to balloon angioplasty may improve procedural outcome.
Assuntos
Angioplastia Coronária com Balão , Doença das Coronárias/terapia , Vasos Coronários/fisiopatologia , Stents , Ultrassonografia de Intervenção , Vasodilatação , Constrição Patológica , Angiografia Coronária , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Humanos , Fluxo Sanguíneo RegionalRESUMO
BACKGROUND: Abnormal coronary vasomotor responses have been described in transplant patients. The aim of this study was to evaluate the graft epicardial vasomotor responses to different stimuli that increase coronary blood flow. METHODS AND RESULTS: Twelve heart transplant recipients with angiographically normal epicardial coronary arteries were compared 2.7 +/- 1.2 months after surgery with 6 control subjects. Coronary flow velocity was measured with a guidewire Doppler. Coronary diameter changes of the proximal and midportion of the left anterior descending coronary artery were assessed by quantitative coronary angiography during rapid atrial pacing, cold pressor test, supine exercise, and subselective infusion of papaverine and after intracoronary injection of linsidomine (SIN-1). Catecholamine plasmatic levels were determined at the different stages of the protocol. In 6 other transplant patients, a cold pressor test was performed before and after intracoronary infusion of phentolamine (10 micrograms.kg-1.min-1). Coronary flow velocity increased significantly in both groups during each phase of the protocol. In control subjects, dilation was observed in response to atrial pacing (8.7 +/- 7.6%; P < .05), CPT (8.8 +/- 2.3%; P < .01), exercise (14.5 +/- 9.4%; P < .001), and papaverine infusion (14.2 +/- 6.1%; P < .001) and after injection of SIN-1 (26.8 +/- 11.9%; P < .001). In transplant patients, similar dilation was observed during atrial pacing (8.2 +/- 8.3%; P < .05) and papaverine infusion (14.6 +/- 7.8%; P < .001) and after SIN-1 (25.8 +/- 10.8%; P < .001). CPT and exercise caused slight constriction (-3.5 +/- 4.5% and -2.7 +/- 10.5%, respectively; both P < .001 versus control subjects). Norepinephrine plasmatic levels increased in both groups during CPT and exercise. Slight constriction during the cold pressor test (-4.5 +/- 9.6%) changed to dilation (6.8 +/- 7.0%) after alpha-blockade with phentolamine (P < .001). CONCLUSIONS: These results show that flow-mediated, endothelium-dependent vasodilation is preserved early after trans-plantation. Sympathetic stimulation, which overrides the endothelium-dependent mechanism, can be related to hypersensitivity to catecholamines due to denervation.
Assuntos
Circulação Coronária/fisiologia , Endotélio Vascular/fisiopatologia , Transplante de Coração , Pericárdio/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Vasodilatação/fisiologia , Antagonistas Adrenérgicos alfa/farmacologia , Adulto , Velocidade do Fluxo Sanguíneo , Estimulação Cardíaca Artificial , Angiografia Coronária , Circulação Coronária/efeitos dos fármacos , Epinefrina/sangue , Feminino , Hemodinâmica , Humanos , Masculino , Norepinefrina/sangue , Valores de Referência , Sistema Vasomotor/efeitos dos fármacos , Sistema Vasomotor/fisiopatologiaRESUMO
A controversy persists as to whether cardiopulmonary bypass (CPB) decreases plasma levels of triiodothyronine (T3), thereby justifying peri-operative administration of T3 to improve haemodynamic recovery. To examine the effects of T3 therapy on post-CPB haemodynamics and to determine whether the potential inotropic effects of T3 are mediated by an increase in beta-adrenergic responsiveness, a prospective, randomized, double-blind, placebo-controlled study was performed in 20 patients undergoing cardiac surgery with CPB. T3 or placebo solution (10 patients in each group) was given intravenously at the time of aortic unclamping and 4, 8, 12 and 20 h thereafter. End points included (1) thyroid hormone levels measured by radioimmunoassay (2) standard haemodynamic parameters (3) the density of lymphocyte beta-adrenoceptors measured by a radioligand (125I-iodocyanopindolol) binding technique. Post-CPB values (cross clamp removal) of T3 (pg.ml-1) were not significantly decreased compared with pre-CPB values: 3.3 +/- 0.2 vs 3.1 +/- 0.2 in controls and 3.3 +/- 0.4 vs 3.7 +/- 0.6 in T3-treated patients, respectively. The haemodynamic parameters were no different between the two groups at any postoperative time point. Likewise, density and affinity of lymphocyte beta-adrenoceptors were not significantly different from pre-operative values in either group. Thus, there seems to be no sound justification for a routine use of T3 in patients undergoing open-heart procedures.
Assuntos
Ponte Cardiopulmonar , Ponte de Artéria Coronária , Doença das Coronárias/cirurgia , Aneurisma Cardíaco/cirurgia , Doenças das Valvas Cardíacas/cirurgia , Próteses Valvulares Cardíacas , Hemodinâmica/efeitos dos fármacos , Tri-Iodotironina/administração & dosagem , Adulto , Doença das Coronárias/fisiopatologia , Feminino , Aneurisma Cardíaco/fisiopatologia , Doenças das Valvas Cardíacas/fisiopatologia , Hemodinâmica/fisiologia , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Receptores Adrenérgicos beta/efeitos dos fármacos , Receptores Adrenérgicos beta/fisiologia , Tri-Iodotironina/sangueRESUMO
A prospective search for episodes of silent myocardial ischaemia (SMI) was carried out during sessions of haemodialysis in 62 patients with chronic renal failure and was positive in 37.1% of the cases. The occurrence of SMI is correlated with the number of cardiovascular risk factors (p = 0.008) and particularly with diabetes (p = 0.012), smoking (p = 0.007) and age (p = 0.02), as well as with the type of nephropathy that had caused the renal failure (p = 0.02). During a 6-month follow-up two patients died; both had silent myocardial ischaemia on Holter recordings. In these anaemic patients, haemodialysis might sensitize the detection of ischaemia by the concomitant occurrence of hypotensive, hypovolaemic or hypoxic episodes, thus playing a aggravating role. The existence of such episodes characterizes a subgroup of patients at high cardiovascular risk for whom the prognosis and the best therapeutic approach remain to be determined.
Assuntos
Doença das Coronárias/etiologia , Falência Renal Crônica/terapia , Diálise Renal/efeitos adversos , Adulto , Feminino , Humanos , Falência Renal Crônica/complicações , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de RiscoRESUMO
Iron catalysis is involved in oxygen-derived free radical generation and subsequent lipid peroxidation, which have been reported to occur during cardiopulmonary bypass in humans. We assessed the effects of the iron chelator deferoxamine on the susceptibility of circulating low density lipoproteins (LDLs) to induced peroxidation in 20 adult patients (10 controls and 10 treated) undergoing cardiopulmonary bypass for coronary or valve procedures. Deferoxamine was given both intravenously (30 mg/kg body wt, starting 30 minutes before bypass and extending for the next 4 hours) and as an additive to the cardioplegic solution (250 mg/l). Blood samples were taken from both atria before and immediately after the end of cardiopulmonary bypass. Plasma lipid peroxidation was assessed by measuring spectrophotometrically the thiobarbituric acid reactive substances (TBARS) content of selectively isolated LDLs after their exposure to a peroxidizing agent. Before cardiopulmonary bypass, the right and left atrial blood values of LDL-TBARS were not significantly different between the two groups. Cardiopulmonary bypass resulted in a lipid peroxidation of significantly greater magnitude in control than in treated patients. Postbypass right atrial values for LDL-TBARS (expressed in mumol/mmol LDL-phospholipids) were 45.7 +/- 17.2 (mean +/- SEM) in control patients and 6.9 +/- 2.9 in treated patients (p less than 0.02), whereas in the left atrial blood, LDL-TBARS yielded values of 62.7 +/- 20.5 and 10.3 +/- 3.9, respectively (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Ponte Cardiopulmonar , Desferroxamina/uso terapêutico , Peroxidação de Lipídeos/efeitos dos fármacos , Feminino , Radicais Livres , Humanos , Ferro/metabolismo , Lipoproteínas LDL/metabolismo , Pulmão/metabolismo , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/prevenção & controleRESUMO
The authors carried out a prospective study to determine the frequency of silent ischemia (SI) in 50 consecutive patients with end stage renal failure during dialysis by Holter monitoring. Twenty patients had SI (40%). This event was related to the number of cardiovascular risk factors (p = 0.0025), principally diabetes, smoking and the underlying renal disease (p = 0.018), and to a history of coronary artery disease (p = 0.0015). Two patients died during the nine months follow-up period and both had SI on Holter monitoring. Dialysis therapy in anaemic patients may predispose to and facilitate the detection of myocardial ischemia by the simultaneous interplay of hypotension, hypovolemia, hypoxia and tachycardia. The detection of these ischemic events may allow identification of a subgroup of dialysis patients with a high cardiovascular risk. The prognosis of these patients and best therapeutic approach require further study.