A practical approach to assess leg muscle oxygenation during ramp-incremental cycle ergometry in heart failure

Heart failure is characterized by the inability of the cardiovascular system to maintain oxygen (O2) delivery (i.e., muscle blood flow in non-hypoxemic patients) to meet O2 demands. The resulting increase in fractional O2 extraction can be non-invasively tracked by deoxygenated hemoglobin concentration (deoxi-Hb) as measured by near-infrared spectroscopy (NIRS). We aimed to establish a simplified approach to extract deoxi-Hb-based indices of impaired muscle O2 delivery during rapidly-incrementing exercise in heart failure. We continuously probed the right vastus lateralis muscle with continuous-wave NIRS during a rampincremental cardiopulmonary exercise test in 10 patients (left ventricular ejection fraction o35%) and 10 age-matched healthy males. Deoxi-Hb is reported as % of total response (onset to peak exercise) in relation to work rate. Patients showed lower maximum exercise capacity and O2 uptake-work rate than controls (Po0.05). The deoxi-Hb response profile as a function of work rate was S-shaped in all subjects, i.e., it presented three distinct phases. Increased muscle deoxygenation in patients compared to controls was demonstrated by: i) a steeper mid-exercise deoxi-Hb-work rate slope (2.2±1.3 vs 1.0±0.3% peak/W, respectively; Po0.05), and ii) late-exercise increase in deoxi-Hb, which contrasted with stable or decreasing deoxi-Hb in all controls. Steeper deoxi-Hb-work rate slope was associated with lower peak work rate in patients (r=–0.73; P=0.01). This simplified approach to deoxi-Hb interpretation might prove useful in clinical settings to quantify impairments in O2 delivery by NIRS during ramp-incremental exercise in individual heart failure patients.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Fed Sao Paulo, Disciplina Cardiol, Sao Paulo, SP, BrazilInst Dante Pazzanese Cardiol, Dept Cardiol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Setor Fisiol Clin Exercicio, Disciplina Pneumol, Sao Paulo, SP, BrazilUniv Fed Rio de Janeiro, Fac Med, Dept Fisioterapia, Rio De Janeiro, RJ, BrazilQueens Univ, Div Resp & Crit Care Med, Lab Clin Exercise Physiol, Kingston, ON, CanadaUniv Fed Sao Paulo, Disciplina Cardiol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Setor Fisiol Clin Exercicio, Disciplina Pneumol, Sao Paulo, SP, BrazilWeb of Scienc

Determination of renal function in long-term heart transplant patients by measurement of urinary retinol-binding protein levels

Significant improvements have been noted in heart transplantation with the advent of cyclosporine. However, cyclosporine use is associated with significant side effects, such as chronic renal failure. We were interested in evaluating the incidence of long-term renal dysfunction in heart transplant recipients. Fifty-three heart transplant recipients were enrolled in the study. Forty-three patients completed the entire evaluation and follow-up. Glomerular (serum creatinine, creatinine clearance measured, and creatinine clearance calculated) and tubular functions (urinary retinol-binding protein, uRBP) were re-analyzed after 18 months. At the enrollment time, the prevalence of renal failure ranged from 37.7 to 54% according to criteria used to define it (serum creatinine> or = 1.5 mg/dL and creatinine clearance <60 mL/min). Mean serum creatinine was 1.61 ± 1.31 mg/dL (range 0.7 to 9.8 mg/dL) and calculated and measured creatinine clearances were 67.7 ± 25.9 and 61.18 ± 25.04 mL min-1 (1.73 m²)-1, respectively. Sixteen of the 43 patients who completed the follow-up (37.2%) had tubular dysfunction detected by increased levels of uRBP (median 1.06, 0.412-6.396 mg/dL). Eleven of the 16 patients (68.7%) with elevated uRBP had poorer renal function after 18 months of follow-up, compared with only eight of the 27 patients (29.6%) with normal uRBP (RR = 3.47, P = 0.0095). Interestingly, cyclosporine trough levels were not different between patients with or without tubular and glomerular dysfunction. Renal function impairment is common after heart transplantation. Tubular dysfunction, assessed by uRBP, correlates with a worsening of glomerular filtration and can be a useful tool for early detection of renal dysfunction

Comparative histopathology of endomyocardial biopsies in chagasic and non-chagasic heart transplant recipients

Background: Heart transplantation has been an option for the treatment of chagasic (C) cardiomyopathy despite difficulties concerning the control of rejection and reactivation. The parasite-host interaction under the influence of immunosuppressive therapy may affect the immunological response to the graft in a pattern different from that in non-chagasic (NC) patients. The aim of this study was to compare the major histopathological features in heart: transplantation in C and NC patients.Methods: We studied 293 endomyocardial biopsies from two groups of heart transplanted patients, including 18 C and 15 NC. Both groups had identical surgical and clinical procedure except immunosuppressive therapy was lower in C patients. The histopathological parameters evaluated were the Quilty effect, rejection, C myocarditis reactivation, fibrosis, hypertrophy, and ischemia. In addition, lymphocytic cellular infiltration of myocarditis due to rejection or reactivation was immunophenotyped in the biopsies of both groups with rejection grades 3 to 4, in biopsies with signs of reactivation, and in fragments of the receptor heart with chronic C myocarditis. A search for Trypanosoma cruzi was performed in all biopsies in the C group in which lymphocyte immunophenotyping was done. We used immunofluorescence and confocal microscopy.Results: The Quilty effect was present in 23% of the biopsies, involving 69.7% of the patients without a significant difference between groups (p = 0.509). Rejection was frequently observed in biopsies with the Quilty effect and the effect often recurred in the same patient. Rejection grades 3 to 4 was more frequent in the C group (p = 0,023). There were 5 episodes of Chagas' disease reactivation with myocarditis in 2 cases. The mean numbers of CD8+ and CD4+ T cells, and the CD4+-to-CD8+ ratio were similar for rejection in both groups (p > 0.05), while the CD4+-to-CD8+ ratio was significantly lower in chronic C myocarditis compared to rejection in the C group (p = 0.043). There was no significant difference in ischemic damage or interstitial fibrosis in the groups but there was a higher frequency of hypertrophy in the NC group (p = 0.007).Conclusions: The histopathological features of heart transplantation in C patients did not differ from that in NC patients in regard to the Quilty effect, development of myocardial fibrosis and ischemia. However, the higher involvement of the C group for rejection grades 3 to 4 suggested higher susceptibility to this event. The similarity of the lymphocytic cellular composition for rejection in both groups indicates that C patients respond to immunological stimulus in a similar pattern as NC patients.UNIFESP, Escola Paulista Med, Dept Patol, Sao Paulo, BrazilUNIFESP, Escola Paulista Med, Disciplina Cardiol, Sao Paulo, BrazilUNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilUNIFESP, Escola Paulista Med, Dept Patol, Sao Paulo, BrazilUNIFESP, Escola Paulista Med, Disciplina Cardiol, Sao Paulo, BrazilUNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilWeb of Scienc

Immunoglobulin A, G, and M levels in pre- and posttransplant sera of cardiac allograft recipients

UNIFESP, Escola Paulista Med, BR-04025002 São Paulo, SP, BrazilUSP, Inst Ciencias Biomed, São Paulo, BrazilUNIFESP, Escola Paulista Med, BR-04025002 São Paulo, SP, BrazilWeb of Scienc

Allo- and autoantibodies in human cardiac allograft recipients

UNIFESP, Escola Paulista Med, BR-04025002 São Paulo, BrazilUNESP, Fac Odontol, Sao Jose Dos Campos, BrazilUNIFESP, Escola Paulista Med, BR-04025002 São Paulo, BrazilWeb of Scienc

Sleep Apnea Worsens Muscle Vasoconstriction During Central and Peripheral Chemoreceptors Stimulation in Patients with Systolic Heart Failure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Sao Paulo, Sch Med, Heart Inst InCor, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Med, Div Cardiol, Sao Paulo, BrazilUniv Calif Los Angeles, Geffen Sch Med, Los Angeles, CA USAUniv Fed Sao Paulo, Dept Med, Div Cardiol, Sao Paulo, BrazilCNPq: 140265/2013-9FAPESP: 2010/50048-1Web of Scienc