RESUMEN
BACKGROUND: The total cavopulmonary connection (TCPC), a palliative correction for congenital defects of the right heart, is based on the corrective technique developed by Fontan and Baudet. Research into the TCPC has primarily focused on reducing power loss through the connection as a means to improve patient longevity and quality of life. The goal of our study is to investigate the efficacy of including a caval offset on the hemodynamics and, ultimately, power loss of a connection. As well, we will quantify the effect of vessel wall compliance on these factors and, in addition, the distribution of hepatic blood to the lungs. METHODS: We employed a computational fluid dynamic model of blood flow in the TCPC that includes both the non-Newtonian shear thinning characteristics of blood and the nonlinear compliance of vessel tissue. RESULTS: Power loss in the rigid-walled simulations decayed exponentially as caval offset increased. The compliant-walled results, however, showed that after an initial substantial decrease in power loss for offsets up to half the caval diameter, power loss increased slightly again. We also found only minimal mixing in both simulations of all offset models. CONCLUSIONS: The increase in power loss beyond an offset of half the caval diameter was due to an increase in the kinetic contribution. Reduced caval flow mixing, on the other hand, was due to the formation of a pressure head in the offset region which acts as a barrier to flow.
Asunto(s)
Velocidad del Flujo Sanguíneo , Puente Cardíaco Derecho/métodos , Modelos Cardiovasculares , Arteria Pulmonar/fisiopatología , Arteria Pulmonar/cirugía , Venas Cavas/fisiopatología , Venas Cavas/cirugía , Presión Sanguínea , Simulación por Computador , Diagnóstico por Computador/métodos , Elasticidad , Cardiopatías Congénitas/fisiopatología , Cardiopatías Congénitas/cirugía , Humanos , Resistencia al Corte , Cirugía Asistida por Computador/métodos , Resistencia VascularRESUMEN
OBJECTIVES: We reviewed our experience with lung transplant for cystic fibrosis (CF) over a 10-year period to identify factors influencing long-term survival. METHODS: One hundred and twenty-three patients with CF have undergone 131 lung transplant procedures at our institution; 114 have had bilateral sequential lung transplants (DLTX) and nine have had bilateral lower lobe transplants from living donors. Three patients had retransplant for acute graft failure, and five had late retransplant for bronchiolitis obliterans syndrome (BOS). Kaplan-Meier survival was calculated for the entire cohort and for subsets at higher risk of death to determine factors predicting a better outcome. RESULTS: Actuarial survival for the entire group of DLTX CF patients was 81% at 1 year, 59% at 5 years, and 38% at 10 years. Lobar transplant was associated with a poorer survival (37.5% at 1 and 5 years). Among DLTX patients, colonization with Burkholderia cepacia was present in 22 patients and was associated with poorer outcome (1- and 5-year survival 60 and 36% in B. cepacia patients vs. 86 and 64% in non-cepacia patients). DLTX patients younger than age 20 (n=22) had a similar survival to patients age 20 or older (n=90). Being on a ventilator at the time of transplant was not associated with poorer survival (n=8). BOS affects increasing numbers of survivors with time. Five CF patients have been retransplanted due to BOS with one operative death and 1-year survival of 60%. CONCLUSIONS: DLTX has acceptable long term survival in CF adults and children with end stage disease. CF patients colonized with B. cepacia have a worse outcome but transplantation is still warranted.
Asunto(s)
Fibrosis Quística/mortalidad , Fibrosis Quística/cirugía , Trasplante de Pulmón/mortalidad , Adolescente , Adulto , Factores de Edad , Bronquiolitis Obliterante/cirugía , Estudios de Seguimiento , Rechazo de Injerto , Humanos , Complicaciones Posoperatorias/cirugía , Reoperación , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
BACKGROUND: Disease of the aortic valve in children and young adults is a complex entity whose management is the subject of controversy. The Ross and the Ross-Konno procedures have become the primary choices for aortic valve replacement in children because of growth potential, optimal hemodynamic performance, and lack of the need for anticoagulation. However, concern persists regarding the longevity of the pulmonary autograft, especially in patients with aortic insufficiency. METHODS: Between June 1993 and February 2000, 72 Ross and Ross-Konno procedures were performed at our institution: 81% of the patients were less than 15 years old. Preoperative, postoperative, and follow-up clinical, echocardiographic, and hemodynamic data were reviewed. Statistical analysis was performed to identify the risk factors for deteriorating autograft function. RESULTS: Aortic insufficiency was an indication for the Ross procedure in 17 patients and mixed lesions with predominant aortic insufficiency in 10. Of the 45 other patients, 32 had aortic stenosis and 13 had mixed lesions with predominant aortic stenosis. There were no deaths during a follow-up of 5 to 80 months. Autograft reoperation was necessary in the follow-up period in 7 patients for severe aortic insufficiency. Moderate insufficiency was identified in 5 additional patients. Aortic insufficiency or predominant aortic insufficiency, as a preoperative hemodynamic indication for the Ross procedure, reached statistical significance (P =.031) as a risk factor for autograft failure. CONCLUSION: The Ross and the Ross-Konno procedures have changed the prognosis of children and young adults with complex aortic valve disease. However, the Ross procedure should be performed with caution in older children in whom aortic insufficiency is a preoperative hemodynamic indication. Further follow-up to delineate the risk factors for autograft dysfunction in children and young adults is necessary to better define the indications for the Ross procedure.
Asunto(s)
Insuficiencia de la Válvula Aórtica/cirugía , Válvula Aórtica , Procedimientos Quirúrgicos Cardíacos , Válvula Pulmonar/trasplante , Adolescente , Adulto , Niño , Preescolar , Femenino , Enfermedades de las Válvulas Cardíacas/cirugía , Humanos , Lactante , Recién Nacido , Masculino , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Factores de Riesgo , Trasplante AutólogoRESUMEN
Studies suggest that pulmonary vascular ischemia-reperfusion injury (IRI) can be attenuated by increasing intracellular cAMP concentrations. The purpose of this study was to determine the effect of IRI on capillary permeability, assessed by capillary filtration coeficient (Kfc), in lungs retrieved from non-heart-beating donors (NHBDs) and reperfused with the addition of the beta(2)-adrenergic receptor agonist isoproterenol (iso), and rolipram (roli), a phosphodiesterase (type IV) inhibitor. Using an in situ isolated perfused lung model, lungs were retrieved from NHBD rats at varying intervals after death and either ventilated with O(2) or not ventilated. The lungs were reperfused with Earle's solution with or without a combination of iso (10 microM) and roli (2 microM). Kfc, lung viability, and pulmonary hemodynamics were measured. Lung tissue levels of adenine nucleotides and cAMP were measured by HPLC. Combined iso and roli (iso/roli) reperfusion decreased Kfc significantly (p < 0.05) compared with non-iso/roli-reperfused groups after 2 h of postmortem ischemia. Total adenine nucleotide (TAN) levels correlated with Kfc in non-iso/roli-reperfused (r = 0.89) and iso/roli-reperfused (r = 0.97) lungs. cAMP levels correlated with Kfc (r = 0.93) in iso/roli-reperfused lungs. Pharmacologic augmentation of tissue TAN and cAMP levels might ameliorate the increased capillary permeability observed in lungs retrieved from NHBDs.
Asunto(s)
AMP Cíclico/metabolismo , Trasplante de Pulmón , Pulmón/metabolismo , Daño por Reperfusión/prevención & control , Donantes de Tejidos , Nucleótidos de Adenina/metabolismo , Agonistas Adrenérgicos beta/administración & dosificación , Agonistas Adrenérgicos beta/farmacología , Animales , Presión Sanguínea , Cadáver , Permeabilidad Capilar , Supervivencia Celular , Cromatografía Líquida de Alta Presión , Isoproterenol/administración & dosificación , Isoproterenol/farmacología , Pulmón/patología , Masculino , Oxígeno/administración & dosificación , Inhibidores de Fosfodiesterasa/farmacología , Circulación Pulmonar , Ratas , Ratas Sprague-Dawley , Reperfusión , Daño por Reperfusión/patología , Rolipram/farmacologíaRESUMEN
BACKGROUND: The perfusion of rat lungs retrieved from cadavers with a solution containing isoproterenol has been shown to ameliorate the ischemia-reperfusion injury seen in lungs retrieved after death, and this protective effect parallels increases in tissue cyclic adenosine monophosphate levels. In this study, we investigated the effect of rolipram, a phosphodiesterase inhibitor, on capillary permeability and lung cyclic adenosine monophosphate levels in lungs retrieved from circulation-arrested rats. METHODS: Using an isolated perfused lung circuit, we retrieved lungs from circulation-arrested donor rats either ventilated with 100% oxygen or not ventilated for varying postmortem times. The lungs were reperfused with or without rolipram (2 micromol/L). The capillary filtration coefficient and wet to dry weight ratio, indicators of pulmonary vascular integrity, were determined, and tissue levels of adenine nucleotides and cyclic adenosine monophosphate were measured by high-performance liquid chromatography. RESULTS: The capillary filtration coefficient was significantly reduced in nonventilated cadaver lungs reperfused with rolipram 120 minutes after death (p<0.05). Oxygen ventilation or reperfusion with rolipram had a similar effect on the capillary filtration coefficient. Cyclic adenosine monophosphate levels were significantly higher in rolipram-reperfused lungs retrieved 120 minutes after death in both oxygen-ventilated (p<0.01) and nonventilated (p<0.01) lungs. CONCLUSIONS: In lungs from nonventilated, circulation-arrested donors, reperfusion with rolipram reduces the ischemia-reperfusion injury that may be due to intracellular cyclic adenosine monophosphate. Alteration of perfusate may have an impact on capillary leak caused by antecedent ischemia. Thus, rolipram may be a useful adjunct in the preservation of donor lungs retrieved after death.
Asunto(s)
Inhibidores de Fosfodiesterasa/farmacología , Pirrolidinonas/farmacología , Daño por Reperfusión/prevención & control , Nucleótidos de Adenina/metabolismo , Animales , Permeabilidad Capilar/efectos de los fármacos , Cromatografía Líquida de Alta Presión , AMP Cíclico/metabolismo , Modelos Animales de Enfermedad , Paro Cardíaco Inducido , Técnicas In Vitro , Pulmón/química , Trasplante de Pulmón , Masculino , Ratas , Ratas Sprague-Dawley , RolipramRESUMEN
Tricuspid valve surgery has been associated with a high operative mortality. This study reviewed 51 patients who underwent 53 tricuspid valve procedures between 1975 and 1989. Most patients (82%) had evidence of rheumatic heart disease. Twenty-six patients (51%) had 42 previous cardiac operations, most involving the mitral valve. Eighty-two percent of patients were New York Heart Association (NYHA) class III or IV preoperatively, and almost all patients had associated disease of other valves. The indication for operation was tricuspid regurgitation in 45 patients, infectious endocarditis in 4, and tricuspid stenosis in 2. The tricuspid abnormality was functional in 67% and organic in 33%. There were 32 tricuspid valve replacements, 20 annuloplasties, and 1 tricuspid valve excision. The hospital mortality rate was 11.8% (six patients). On statistical analysis, none of the perioperative variables were a significant risk factor for hospital mortality. Twenty-nine patients (51%) had postoperative complications. Postoperative functional status improved markedly with 80% in NYHA class I and 13% in class II. Long-term follow-up was attempted but was unsatisfactory in this transient, indigent population.
Asunto(s)
Prótesis Valvulares Cardíacas , Complicaciones Posoperatorias/fisiopatología , Cardiopatía Reumática/cirugía , Válvula Tricúspide/cirugía , Adolescente , Adulto , Anciano , Distribución de Chi-Cuadrado , Niño , Femenino , Estudios de Seguimiento , Prótesis Valvulares Cardíacas/efectos adversos , Prótesis Valvulares Cardíacas/métodos , Humanos , Masculino , Persona de Mediana Edad , Cardiopatía Reumática/fisiopatología , Tasa de SupervivenciaRESUMEN
The presence of a perivalvular abscess is associated with an increased risk of morbidity and mortality with valve replacement and can require extensive debridement and reconstructive procedures. An accurate noninvasive method for preoperative diagnosis may hasten operation and aid in preoperative and surgical management. Two cases are presented in which ultrafast computed tomography accurately identified perivalvular abscesses not detected on two-dimensional transthoracic echocardiography and guided operative intervention.
Asunto(s)
Absceso/diagnóstico por imagen , Cardiopatías/diagnóstico por imagen , Enfermedades de las Válvulas Cardíacas/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Válvula Aórtica/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Válvula Mitral/diagnóstico por imagenRESUMEN
Since LV hypertrophy is an independent predictor of increased cardiac mortality, a simple noninvasive measure of LV mass would be a valuable screening tool. A retrospective assessment of 50 UFCT studies was performed. Measurements of LV mass, TBV, and TLV were determined in each case. There was excellent correlation between TBV and LVM (R = 0.93) and between TLV and LV mass (R = 0.92). Also, there was minimal interobserver variability between two independent observers for estimates of both TBV (R = 0.995) and TLV (R = 0.99). Thus these preliminary data indicate that LV mass may be estimated from TBV or TLV and that these tools may assist in the identification of patients potentially at high risk for future coronary events, as indicated by the presence of increased LV mass and coronary atherosclerosis.
Asunto(s)
Ventrículos Cardíacos/diagnóstico por imagen , Hipertrofia Ventricular Izquierda/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Coronaria/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
Ultrafast computed tomography (CT) is a new imaging technique that relies on electron beam technology. Its short scanning acquisition times eliminate the motion artifacts seen with conventional CT. High temporal and spatial resolution make it ideal for evaluating the heart using only modest amounts of intravenous contrast. Ultrafast CT is extremely valuable for diagnosis and assessment of intracardiac thrombus and cardiac tumors. Although echocardiography is widely used to identify intracardiac thrombus, it sometimes cannot visualize the most common sites, the atria (especially the left atrial appendage) and the cardiac apex. These areas are clearly defined by ultrafast CT. Likewise, the location, size, extent, and tissue density of primary or metastatic cardiac tumors can be characterized using ultrafast CT, which may obviate the need for angiography before operative treatment.
Asunto(s)
Cardiopatías/diagnóstico por imagen , Neoplasias Cardíacas/diagnóstico por imagen , Mixoma/diagnóstico por imagen , Trombosis/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Atrios Cardíacos , Humanos , Procesamiento de Imagen Asistido por ComputadorRESUMEN
Rapid and accurate detection of great vessel disease is of enormous importance in clinical practice. The search continues for the best technique to evaluate critically ill patients with acute aortic dissection and/or acute pulmonary embolism. Because of its speed and excellent spatial resolution, ultrafast computed tomography (CT) is a very useful tool and may alter the management of patients with aortic disease. Other techniques, such as magnetic resonance imaging (MRI) and transesophageal echocardiography (TEE) are also used in the diagnosis of aortic dissection. Each technique has advantages and pitfalls. At this time it is likely that one technique will complement the other. With further technical improvements, both MRI and ultrafast CT are likely to emerge as the diagnostic tests of choice. In the future, further validation and comparative studies in the acute setting may help to identify the most accurate and useful technique.
Asunto(s)
Aneurisma de la Aorta/diagnóstico por imagen , Coartación Aórtica/diagnóstico por imagen , Disección Aórtica/diagnóstico por imagen , Embolia Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Aortografía/métodos , Predicción , Humanos , Tomografía Computarizada por Rayos X/tendenciasRESUMEN
Ultrafast computed tomography (CT) is a new imaging technique that relies on electron beam technology. Its rapid image acquisition speeds make it ideal for evaluating the cardiovascular system. The high-resolution, flow, and cine-modes are unique and provide complimentary information about cardiovascular anatomy, function, and flow dynamics. Ultrafast CT can provide quantitative measurements of cardiac output, ejection fraction, ventricular volumes, and ventricular mass as well as evaluation of segmental cardiac function. This technique can be used to assess coronary artery bypass graft patency as well as to screen for coronary artery calcium. Intracardiac thrombus or tumor, valvular disease, and disorders of the pericardium can be evaluated and characterized using ultrafast CT. The diagnosis of congenital lesions of the heart and great vessels is facilitated by this imaging modality, which can help determine complex anatomic abnormalities and quantitate shunt lesions. Acquired lesions of the great vessels, such as aortic dissection and aneurysm, can be diagnosed by ultrafast CT, which can also be used for serial examination and conservative management.