Liliana E. Favaloro

Myocardial Viability and Survival in Ischemic Left Ventricular Dysfunction

BACKGROUND The assessment of myocardial viability has been used to identify patients with coronary artery disease and left ventricular dysfunction in whom coronary-artery bypass grafting (CABG) will provide a survival benefit. However, the efficacy of this approach is uncertain. METHODS In a substudy of patients with coronary artery disease and left ventricular dysfunction who were enrolled in a randomized trial of medical therapy with or without CABG, we used single-photon-emission computed tomography (SPECT), dobutamine echocardiography, or both to assess myocardial viability on the basis of prespecified thresholds. RESULTS Among the 1212 patients enrolled in the randomized trial, 601 underwent assessment of myocardial viability. Of these patients, we randomly assigned 298 to receive medical therapy plus CABG and 303 to receive medical therapy alone. A total of 178 of 487 patients with viable myocardium (37%) and 58 of 114 patients without viable myocardium (51%) died (hazard ratio for death among patients with viable myocardium, 0.64; 95% confidence interval [CI], 0.48 to 0.86; P=0.003). However, after adjustment for other baseline variables, this association with mortality was not significant (P=0.21). There was no significant interaction between viability status and treatment assignment with respect to mortality (P=0.53). CONCLUSIONS The presence of viable myocardium was associated with a greater likelihood of survival in patients with coronary artery disease and left ventricular dysfunction, but this relationship was not significant after adjustment for other baseline variables. The assessment of myocardial viability did not identify patients with a differential survival benefit from CABG, as compared with medical therapy alone. (Funded by the National Heart, Lung, and Blood Institute; STICH ClinicalTrials.gov number, NCT00023595.).

Molecular identification of Trypanosoma cruzi discrete typing units in end-stage chronic Chagas heart disease and reactivation after heart transplantation.

BACKGROUND One hundred years after the discovery of Chagas disease, it remains a major neglected tropical disease. Chronic Chagas heart disease (cChHD) is the most severe manifestation. Heart transplantation is the proper treatment for end-stage heart failure, although reactivation of disease may result after receipt of immunosuppressive therapy. T. cruzi strains cluster into 6 discrete typing units (DTUs; I-VI) associated with different geographical distribution, transmission cycles and varying disease symptoms. In the southern cone of South America, T. cruzi II, V, and VI populations appear to be associated with Chagas disease and T. cruzi I with sylvatic cycles. METHODS Molecular characterization of DTUs, T. cruzi I genotypes (on the basis of spliced-leader gene polymorphisms), and minicircle signatures was conducted using cardiac explant specimens and blood samples obtained from a cohort of 16 Argentinean patients with cChHD who underwent heart transplantation and from lesion samples obtained from 6 of these patients who presented with clinical reactivation of Chagas disease. RESULTS Parasite persistence was associated with myocarditis progression, revealing T. cruzi I (genotype Id) in 3 explant samples and T. cruzi II, V, or VI in 5 explant samples. Post-heart transplantation follow-up examination of bloodstream DTUs identified T. cruzi I in 5 patients (genotypes Ia or Id) and T. cruzi II, V, or VI in 7 patients. T. cruzi I, V, and VI were detected in skin chagoma specimens, and T. cruzi V and VI were detected in samples obtained from patients with myocarditis reactivations. Multiple DTUs or genotypes at diverse body sites and polymorphic minicircle signatures at different cardiac regions revealed parasite histotropism. T. cruzi I infections clustered in northern Argentina (latitude, 23 degrees S-27 degrees S), whereas T. cruzi II, V, or VI DTUs were more ubiquitous. CONCLUSIONS Multiple DTUs coexist in patients with Chagas disease. The frequent finding of T. cruzi I associated with cardiac damage was astounding, revealing its pathogenic role in cChHD at the southern cone.

Usefulness of PCR Strategies For Early Diagnosis of Chagas' Disease Reactivation and Treatment Follow-Up in Heart Transplantation

Heart transplantation (HTx) is a useful therapy for end‐stage Chagaś cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.

Cardiomyocyte hypertrophy, oncosis, and autophagic vacuolization predict mortality in idiopathic dilated cardiomyopathy with advanced heart failure.

OBJECTIVES The aim of this study was to identify the remodeling parameters cardiomyocyte (CM) damage or death, hypertrophy, and fibrosis that may be linked to outcomes in patients with advanced heart failure (HF) in an effort to understand the pathogenic mechanisms of HF that may support newer therapeutic modalities. BACKGROUND There are controversial results on the influence of fibrosis, CM hypertrophy, and apoptosis on outcomes in patients with HF; other modalities of cell damage have been poorly investigated. METHODS In endomyocardial biopsy specimens from 100 patients with idiopathic dilated cardiomyopathy and advanced HF, CM diameter and the extent of fibrosis were determined by morphometry. The proportion of CMs with evidence of apoptosis, autophagic vacuolization (AuV), and oncosis was investigated by immunohistochemical methods and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. Those parameters were correlated with mortality in 3 years of follow-up by univariate analysis and with multivariate models incorporating the clinical variables more relevant to the prediction of outcomes. RESULTS CM AuV occurred in 28 patients (0.013 ± 0.012%) and oncosis in 41 (0.109 ± 0.139%). Nineteen patients showed both markers. Apoptotic CM nuclei were observed in 3 patients. In univariate analysis, CM diameter and AuV, either alone or associated with oncosis, were predictors of mortality. In multivariate analysis, CM diameter (hazard ratio: 1.37; 95% confidence interval: 1.12 to 1.68; p = 0.002) and simultaneous presence in the same endomyocardial biopsy specimen of AuV and oncosis (hazard ratio: 2.82; 95% confidence interval: 1.12 to 7.13; p = 0.028) were independent predictors of mortality. CONCLUSIONS CM hypertrophy and AuV, especially in association with oncosis, are predictors of outcome in patients with idiopathic dilated cardiomyopathy and severe HF.

Presence of antigen-experienced T cells with low grade of differentiation and proliferative potential in chronic Chagas disease myocarditis

Background The main consequence of chronic Trypanosoma cruzi infection is the development of myocarditis in approximately 20–30% of infected individuals but not until 10–20 years after the initial infection. We have previously shown that circulating interferon-γ-secreting T cells responsive to Trypanosoma cruzi antigens in chronic Chagas disease patients display a low grade of differentiation and the frequency of these T lymphocytes decreases along with the severity of heart disease. This study thought to explore the expression of inhibitory receptors, transcription factors of type 1 or regulatory T cells, and markers of T cell differentiation, immunosenescence or active cell cycle in cardiac explants from patients with advanced Chagas disease myocarditis. Methodology/Principal Findings The expression of different markers for T and B cells as well as for macrophages was evaluated by immunohistochemistry and immunofluorescence techniques in cardiac explants from patients with advanced chronic Chagas disease submitted to heart transplantation. Most infiltrating cells displayed markers of antigen-experienced T cells (CD3+, CD4+, CD8+, CD45RO+) with a low grade of differentiation (CD27+, CD57−, CD45RA−, PD-1−). A skewed T helper1/T cytotoxic 1 profile was supported by the expression of T-bet; whereas FOXP3+ cells were scarce and located only in areas of severe myocarditis. In addition, a significant proliferative capacity of CD3+ T cells, assessed by Ki67 staining, was found. Conclusions/Significance The quality of T cell responses and immunoregulatory mechanisms might determine the pattern of the cellular response and the severity of disease in chronic Trypanosoma cruzi infection.

Coronary Microcirculation Remodeling in Patients with Idiopathic Dilated Cardiomyopathy

Background: In patients with idiopathic dilated cardiomyopathy (IDCM), the myocardial blood flow is markedly depressed. The presence of alterations in the number and length of the coronary microcirculation has not been explored. Methods: In explanted hearts of 6 patients with IDCM and in 6 normal control hearts, the arteriolar length density and capillary numerical density were determined in sections stained with orcein (vessels 50–200 µm in diameter), for smooth muscle actin (vessels 6–50 µm in diameter) and CD34 (capillaries). Results: No difference with normal hearts was observed in capillary numerical density and in length density of vessels above 50 µm in diameter. In IDCM, more than 50% of arterioles below 50 µm in diameter displayed an incomplete smooth muscle wall, and length density, especially for arterioles between 6 and 20 µm in diameter, was significantly lower (42.84 ± 8.51 mm/mm3) than in controls (75.34 ± 3.05 mm/mm3, p = 0.001). Conclusions: In IDCM, arterioles below 50 µm in diameter display an incomplete smooth muscle wall and a significant decrease in length density. These observations provide an anatomical basis for a decreased coronary flow reserve in IDCM.

Sex difference in patients with ischemic heart failure undergoing surgical revascularization results from the STICH trial (surgical treatment for ischemic heart failure)

Background: Female sex is conventionally considered a risk factor for coronary artery bypass grafting (CABG) and has been included as a poor prognostic factor in multiple cardiac operative risk evaluation scores. We aimed to investigate the association of sex and the long-term benefit of CABG in patients with ischemic left ventricular dysfunction enrolled in the prospective STICH trial (Surgical Treatment for Ischemic Heart Failure Study). Methods: The STICH trial randomized 1212 patients (148 [12%] women and 1064 [88%] men) with coronary artery disease and left ventricular ejection fraction ⩽35% to CABG+medical therapy (MED) versus MED alone. Long-term (10-year) outcomes with each treatment were compared according to sex. Results: At baseline, women were older (63.4 versus 59.3 years; P=0.016) with higher body mass index (27.9 versus 26.7 kg/m2; P=0.001). Women had more coronary artery disease risk factors (diabetes mellitus, 55.4% versus 37.2%; hypertension, 70.9% versus 58.6%; hyperlipidemia, 70.3% versus 58.9%) except for smoking (13.5% versus 21.8%) and had lower rates of prior CABG (0% versus 3.4%; all P<0.05) than men. Moreover, women had higher New York Heart Association class (class III/IV, 66.2% versus 57.0%), lower 6-minute walk capacity (300 versus 350 m), and lower Kansas City Cardiomyopathy Questionnaire overall summary scores (51 versus 63; all P<0.05). Over 10 years of follow-up, all-cause mortality (49.0% versus 65.8%; adjusted hazard ratio, 0.67; 95% confidence interval, 0.52–0.86; P=0.002) and cardiovascular mortality (34.3% versus 52.3%; adjusted hazard ratio, 0.65; 95% confidence interval, 0.48–0.89; P=0.006) were significantly lower in women compared with men. With randomization to CABG+MED versus MED treatment, there was no significant interaction between sex and treatment group in all-cause mortality, cardiovascular mortality, or the composite of all-cause mortality or cardiovascular hospitalization (all P>0.05). In addition, surgical deaths were not statistically different (1.5% versus 5.1%; P=0.187) between sexes among patients randomized to CABG per protocol as initial treatment. Conclusions: Sex is not associated with the effect of CABG+MED versus MED on all-cause mortality, cardiovascular mortality, the composite of death or cardiovascular hospitalization, or surgical deaths in patients with ischemic left ventricular dysfunction. Thus, sex should not influence treatment decisions about CABG in these patients. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00023595.

The association between blood pressure and long-term outcomes of patients with ischaemic cardiomyopathy with and without surgical revascularization: an analysis of the STICH trial

Aims Hypertension (HTN) is a well-known contributor to cardiovascular disease, including heart failure (HF) and coronary artery disease, and is the leading risk factor for premature death world-wide. A J- or U-shaped relationship has been suggested between blood pressure (BP) and clinical outcomes in different studies. However, there is little information about the significance of BP on the outcomes of patients with coronary artery disease and left ventricular dysfunction. This study aimed to determine the relationship between BP and mortality outcomes in patients with ischaemic cardiomyopathy. Methods and results The influence of BP during a median follow-up of 9.8 years was studied in a total of 1212 patients with ejection fraction ≤35% and coronary disease amenable to coronary artery bypass grafting (CABG) who were randomized to CABG or medical therapy alone (MED) in the STICH (Surgical Treatment for Ischaemic Heart Failure) trial. Landmark analyses were performed starting at 1, 2, 3, 4, and 5 years after randomization, in which previous systolic BP values were averaged and related to subsequent mortality through the end of follow-up with a median of 9.8 years. Neither a previous history of HTN nor baseline BP had any significant influence on long-term mortality outcomes, nor did they have a significant interaction with MED or CABG treatment. The landmark analyses showed a progressive U-shaped relationship that became strongest at 5 years (χ2 and P-values: 7.08, P = 0.069; 8.72, P = 0.033; 9.86; P = 0.020; 8.31, P = 0.040; 14.52, P = 0.002; at 1, 2, 3, 4, and 5-year landmark analyses, respectively). The relationship between diastolic BP (DBP) and outcomes was similar. The most favourable outcomes were observed in the SBP range 120-130, and DBP 75-85 mmHg, whereas lower and higher BP were associated with worse outcomes. There were no differences in BP-lowering medications between groups. Conclusion A strong U-shaped relationship between BP and mortality outcomes was evident in ischaemic HF patients. The results imply that the optimal SBP might be in the range 120-130 mmHg after intervention, and possibly be subject to pharmacologic action regarding high BP. Further, low BP was a marker of poor outcomes that might require other interactions and treatment strategies. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00023595.