Risk prediction in patients with classical low-flow, low-gradient aortic stenosis undergoing surgical intervention

Introduction

Classical low-flow, low-gradient aortic stenosis (LFLG-AS) is an advanced stage of aortic stenosis, which has a poor prognosis with medical treatment and a high operative mortality after surgical aortic valve replacement (SAVR). There is currently a paucity of information regarding the current prognosis of classical LFLG-AS patients undergoing SAVR and the lack of a reliable risk assessment tool for this particular subset of AS patients. The present study aims to assess mortality predictors in a population of classical LFLG-AS patients undergoing SAVR.

Methods

This is a prospective study including 41 consecutive classical LFLG-AS patients (aortic valve area ≤1.0 cm², mean transaortic gradient <40 mmHg, left ventricular ejection fraction <50%). All patients underwent dobutamine stress echocardiography (DSE), 3D echocardiography, and T1 mapping cardiac magnetic resonance (CMR). Patients with pseudo-severe aortic stenosis were excluded. Patients were divided into groups according to the median value of the mean transaortic gradient (≤25 and >25 mmHg). All-cause, intraprocedural, 30-day, and 1-year mortality rates were evaluated.

Results

All of the patients had degenerative aortic stenosis, with a median age of 66 (60-73) years; most of the patients were men (83%). The median EuroSCORE II was 2.19% (1.5%-4.78%), and the median STS was 2.19% (1.6%-3.99%). On DSE, 73.2% had flow reserve (FR), i.e., an increase in stroke volume ≥20% during DSE, with no significant differences between groups. On CMR, late gadolinium enhancement mass was lower in the group with mean transaortic gradient >25 mmHg [2.0 (0.0-8.9) g vs. 8.5 (2.3-15.0) g; p = 0.034), and myocardium extracellular volume (ECV) and indexed ECV were similar between groups. The 30-day and 1-year mortality rates were 14.6% and 43.8%, respectively. The median follow-up was 4.1 (0.3-5.1) years. By multivariate analysis adjusted for FR, only the mean transaortic gradient was an independent predictor of mortality (hazard ratio: 0.923, 95% confidence interval: 0.864-0.986, p = 0.019). A mean transaortic gradient ≤25 mmHg was associated with higher all-cause mortality rates (log-rank p = 0.038), while there was no difference in mortality regarding FR status (log-rank p = 0.114).

Conclusions

In patients with classical LFLG-AS undergoing SAVR, the mean transaortic gradient was the only independent mortality predictor in patients with LFLG-AS, especially if ≤25 mmHg. The absence of left ventricular FR had no prognostic impact on long-term outcomes.

Postoperative myocardial fibrosis assessment in aortic valvular heart diseases-a cardiovascular magnetic resonance study

AIMS

Left ventricular remodelling occurs during the chronic course of aortic regurgitation (AR) and aortic stenosis (AS), leading to myocardial hypertrophy and fibrosis. Several studies have shown that extracellular volume fraction (ECV) and indexed extracellular volume (iECV) are important surrogate markers of diffuse myocardial fibrosis (MF). Postoperative data on these cardiovascular magnetic resonance (CMR) extracellular expansion parameters for either AS or AR are scarce. This study aimed to demonstrate the postoperative changes that occur in diffuse MF, and the influence of preoperative MF on the reversal of LV remodelling, in patients with AR or AS.

METHODS AND RESULTS

Patients with severe AR or AS and indications for surgery were prospectively enrolled. Patients underwent pre- and postoperative CMR, and ECV and iECV were quantified. Data from 99 patients were analysed (32 with AR and 67 with AS). After surgery, the left ventricle mass index decreased in both groups (AR: 110 vs. 91 g/m2; AS: 86 vs. 68 g/m2, both P < 0.001). The late gadolinium enhancement fraction (AR: preoperative 1.9% vs. postoperative 1.7%, P = 0.575; AS: preoperative 2.4% vs. postoperative 2.4%, P = 0.615) and late gadolinium enhancement mass (AR: preoperative 3.8 g vs. postoperative 2.5 g, P = 0.635; AS: preoperative 3.4 g vs. postoperative 3.5 g, P = 0.575) remained stable in both groups. Preoperative iECV and ECV were greater in the AR group (iECV: 30 mL/m2 vs. 22 mL/m2, P = 0.001; ECV: 28.4% vs. 27.2%, P = 0.048). Indexed extracellular volume decreased after surgery in both groups (AR: 30-26.5 mL/m2, AS: 22-18.2 mL/m2, both P < 0.001); it was still greater in the AR group (AR: 26.5 mL/m2 vs. AS: 18.2 mL/m2, P < 0.001). Postoperative ECV remained stable in the AR group (preoperative 28.4% vs. postoperative 29.9%; P = 0.617) and increased in the AS group (preoperative 27.2% vs. postoperative 28.6%; P = 0.033).

CONCLUSION

Patients with both AR or AS presented reduction in iECV after surgery, unfolding the reversible nature of diffuse MF. In contrast to patients with AS, those with AR developed postoperative iECV regression with stable ECV, suggesting a balanced reduction in both intracellular and extracellular myocardial components.

Transcatheter aortic valve implantation without contrast media technique in chronic kidney disease population – pilot study

Background/Introduction

Acute Kidney Injury (AKI) is frequently observed after Transcatheter aortic valve implantation (TAVI), with rates ranging from 3% to 50%. In the Brazilian TAVI Registry, the incidence of AKI following TAVI was 18%, with 4.5% requiring dialysis. Its occurrence is associated with an increase in 3-fold all-cause and cardiac death. Since AKI is related to the volume of contrast media, avoiding contrast during TAVI procedure is advisable, especially in chronic kidney disease (CKD) patients.

Purpose

The aims of the proposed study are to: (1) evaluate the feasibility and safety of a zero-contrast technique for CKD patients undergoing TAVI and (2) define the role of each of the non-contrast imaging modalities in the preoperative assessment for TAVI and (3) evaluate the incidence of AKI post-TAVI in this population.

Methods

Patients with severe symptomatic aortic stenosis (AS) and CKD stage ≥3a where evaluated for TAVI with four preoperative exams: transesophageal echocardiogram (TEE), cardiac magnetic resonance, contrast and noncontrast computed tomography (MDCT) and aortoiliac co2 angiography. After safety measures of transfemoral (TF) viability and aortic valve favorable anatomy, patients were submitted to TF-TAVI with self-expandable Evolut R/Pro. The contrast MDCT was blinded to the operators and it is checked before the procedure, at a safety checkpoint, to exclude high-risk conditions not detected by non-contrast methods. During the procedure, another safety checkpoint was accomplished. Clinical and echocardiographic outcomes were assessed at 30 days.

Results

Between december 2020 to december 2021, a total of 25 patients underwent TF TAVI with zero-contrast technique. Mean age of 79.9±6.1 years, 52% male, 18 patients (72%) NYHA functional class III or IV, mean STS-PROM 3.0±1.5%, 12% had severe systolic dysfunction (left ventricle ejection fraction &lt;35%) and mean creatinine clearance of 49.1±7 mL/min. Self-expandable Evolut R was implanted in 80% of patients and Evolut Pro in 20% of them, the most frequent THV size was 29 mm (52%) and the mean implant depth was 6 mm in fluoroscopy and 4.5 mm in TEE. The mean procedural time was 138±56 minutes, with a median radiation dose of 6.6 mGy/cm2 [IQR, 2–6 mGy]. Definitive pacemaker was implanted in 17% of patients and AKI was seen in 6 patients (24%), with stage I (20%), stage II (4%) and no case needed hemodialysis. At 30 days, 84% were at functional class I, there was no death, one embolization requiring a second valve and the rate of device success (VARC-2) was 92%.

Conclusion

The proposed pilot study for transfemoral TAVI in CKD population with zero contrast technique was safe, with promising results and similar rates of success and complication, compared with the conventional TAVI approach.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): MedtronicAngiodroid

P6483Predictors of contractile reserve on dobutamine stress echocardiography in patients with classical low-flow, low-gradient aortic stenosis

Background

There is a lack of information on factors that influence contractile reserve (CR) on dobutamine stress echocardiography (DSE) in patients with classical low-flow, low-gradient aortic stenosis (LFLG-AS).

Purpose

This study sought to evaluate the predictors of CR in patients with LFLG-AS.

Methods

Prospective study including 43 consecutive LFLG-AS patients (aortic valve area [AVA] ≤1.0 cm2, mean transaortic gradient <40 mmHg, left ventricular ejection fraction [LVEF] <50%) with true severe aortic stenosis. All patients underwent dobutamine stress echocardiography and T1-mapping cardiac magnetic resonance (CMR). CR was defined as an increase ≥20% in the left ventricular stroke volume at peak stress. Patients with pseudo-severe aortic stenosis were excluded.

Results

All of the patients in the study had degenerative aortic stenosis, with a median age of 67 [60–74] years, most of them being male (83.7%). A high prevalence of comorbidities was found, highlighted by diabetes (42%), hypertension (70%), atrial fibrillation (25%) and coronary artery disease (38%). Mean transaortic gradient was 25 [20–33] mmHg, AVA was 0.88 [0.68–0.95] cm2, LVEF was 35 [28–43]% and 32.6% had moderate/severe functional mitral regurgitation. CMR myocardium extracellular volume fraction (ECV) was 28.8 [26.3–33.0] %, indexed ECV was 35.4 [25.0–41.2] ml/m2, 32.6% had positive transmural delayed-enhancement images and 25.6% had positive mesocardial delayed-enhancement images. On DSE, 30 patients (69.7%) had CR and 13 patients (30.3%) had no CR. Global longitudinal strain was 10 [7–12] %, Δ indexed flow rate was 25 [3–38] ml/m2.seg and Δ mean gradient was 10 [3–16] mmHg. By multivariate analysis, moderate/severe functional mitral regurgitation (HR 0.122, 95% CI 0.020–0.759, p=0.024) and AVA (HR 0.606, 95% CI 0.396–0.925, p=0.020 [for each increase of 0.05 cm2]) were the only factors associated with CR. ECV, indexed ECV and positive transmural or mesocardial delayed-enhancement images were not associated with CR in the univariate analysis.

Conclusions

In our study, the absence of moderate/severe functional mitral regurgitation and AVA were predictors of CR on DSE in patients with LFLG-AS. As AVA was smaller in patients with CR, our finding contradicts the hypothesis that more severe aortic stenosis could also contribute to the lack of CR. Other possible factors that are surrogate of myocardium fibrosis, as ECV, indexed ECV and positive delayed-enhancement images, were not associated with the absence of CR.

Acknowledgement/Funding

FAPESP

Thrombocytopenia After Transcatheter Valve-in-Valve Implantation: Prognostic Marker or Mere Finding?

Objective

To analyze the behavior of platelets after transcatheter valve-in-valve implantation for the treatment of degenerated bioprosthesis and how they correlate with adverse events upon follow-up.

Methods

Retrospective analysis of 28 patients who received a valve-in-valve implant, 5 in aortic, 18 in mitral and 5 in tricuspid positions. Data were compared with 74 patients submitted to conventional redo valvular replacements during the same period, and both groups' platelet curves were analyzed. Statistical analysis was conducted using the IBM SPSS Statistics(r) 20 for Windows.

Results

All patients in the valve-in-valve group developed thrombocytopenia, 25% presenting mild (<150.000/µL), 54% moderate (<100.000/µL) and 21% severe (<50.000/µL) thrombocytopenia. The platelet nadir was on the 4^th postoperative day for aortic ViV, 2^nd for mitral and 3^rd for tricuspid patients, with the majority of patients recovering regular platelet count. However, the aortic subgroup comparison between valve-in-valve and conventional surgery showed a statistically significant difference from the 7^th day onwards, where valve-in-valve patients had more severe and longer lasting thrombocytopenia. This, however, did not translate into a higher postoperative risk. In our study population, postoperative thrombocytopenia did not correlate with greater occurrence of adverse outcomes and only normal preoperative platelet count could significantly predict a postoperative drop >50%.

Conclusion

Although thrombocytopenia is an extremely common finding after valve-in-valve procedures, the degree of platelet count drop did not correlate with greater incidence of postoperative adverse outcomes in our study population.

Predictive performance of six mortality risk scores and the development of a novel model in a prospective cohort of patients undergoing valve surgery secondary to rheumatic fever

BACKGROUND

Mortality prediction after cardiac procedures is an essential tool in clinical decision making. Although rheumatic cardiac disease remains a major cause of heart surgery in the world no previous study validated risk scores in a sample exclusively with this condition.

OBJECTIVES

Develop a novel predictive model focused on mortality prediction among patients undergoing cardiac surgery secondary to rheumatic valve conditions.

METHODS

We conducted prospective consecutive all-comers patients with rheumatic heart disease (RHD) referred for surgical treatment of valve disease between May 2010 and July of 2015. Risk scores for hospital mortality were calculated using the 2000 Bernstein-Parsonnet, EuroSCORE II, InsCor, AmblerSCORE, GuaragnaSCORE, and the New York SCORE. In addition, we developed the rheumatic heart valve surgery score (RheSCORE).

RESULTS

A total of 2,919 RHD patients underwent heart valve surgery. After evaluating 13 different models, the top performing areas under the curve were achieved using Random Forest (0.982) and Neural Network (0.952). Most influential predictors across all models included left atrium size, high creatinine values, a tricuspid procedure, reoperation and pulmonary hypertension. Areas under the curve for previously developed scores were all below the performance for the RheSCORE model: 2000 Bernstein-Parsonnet (0.876), EuroSCORE II (0.857), InsCor (0.835), Ambler (0.831), Guaragna (0.816) and the New York score (0.834). A web application is presented where researchers and providers can calculate predicted mortality based on the RheSCORE.

CONCLUSIONS

The RheSCORE model outperformed pre-existing scores in a sample of patients with rheumatic cardiac disease.

Relation of mitral valve morphology to surgical repair results in patients with mitral valve prolapse: A three-dimensional transesophageal echocardiography study

BACKGROUND

The identification of predictors of mitral valve (MV) repair results is important for quality improvement in cardiac surgery. The aim of this study was to evaluate the relationship between MV morphological quantification by three-dimensional (3D) transesophageal echocardiography and mitral repair results.

METHODS

Fifty-four patients with MV prolapse who were submitted to surgical repair were divided into 2 groups according to their postoperative mitral regurgitation (MR) degree (group 1, grade 0-I MR; group 2, ≥grade II MR). Morphological parameters related to the mitral ring, dimension of leaflets and prolapse, coaptation line, distance from papillary muscles to the leaflet border and valve angles were analyzed by 3D MV quantification. Cardiac remodeling and MR quantitative parameters were also evaluated.

RESULTS

There was no correlation between 3D MV quantification and surgical results; a multivariate analysis did not show an association between morphological parameters and surgical outcome. The distance from the posteromedial papillary muscle to the leaflet border was higher (P = .038) in patients with ≥grade II postoperative MR. The left atrial diameter, left ventricular end-systolic diameter, left ventricular end-diastolic and end-systolic volumes were larger in patients with a significant residual MR (P < .05).

CONCLUSION

Three-dimensional MV quantification did not predict the postoperative MR grade; however, the distance from the posteromedial papillary muscles to the leaflet border may be related to suboptimal repair results. Furthermore, excessive cardiac remodeling was related to postoperative MR ≥ grade II, what could suggest a potential benefit of early surgical treatment.

Do We Need to Personalize Renal Function Assessment in the Stratification of Patients Undergoing Cardiac Surgery?

Background

Renal dysfunction is an independent predictor of morbidity and mortality in cardiac surgery. For a better assessment of renal function, calculation of creatinine clearance (CC) may be necessary.

Objective

To objectively evaluate whether CC is a better risk predictor than serum creatinine (SC) in patients undergoing cardiac surgery.

Methods

Analysis of 3,285 patients registered in a prospective, consecutive and mandatory manner in the Sao Paulo Registry of Cardiovascular Surgery (REPLICCAR) between November 2013 and January 2015. Values of SC, CC (Cockcroft-Gault) and EuroSCORE II were obtained. Association analysis of SC and CC with morbidity and mortality was performed by calibration and discrimination tests. Independent multivariate models with SC and CC were generated by multiple logistic regression to predict morbidity and mortality following cardiac surgery.

Results

Despite the association between SC and mortality, it did not calibrate properly the risk groups. There was an association between CC and mortality with good calibration of risk groups. In mortality risk prediction, SC was uncalibrated with values > 1.35 mg /dL (p < 0.001). The ROC curve showed that CC is better than SC in predicting both morbidity and mortality risk. In the multivariate model without CC, SC was the only predictor of morbidity, whereas in the model without SC, CC was not only a mortality predictor, but also the only morbidity predictor.

Conclusion

Compared with SC, CC is a better parameter of renal function in risk stratification of patients undergoing cardiac surgery.

The use of a high-power laser on swine mitral valve chordae tendineae

Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

Immunohistochemical quantification of inflammatory cells in endomyocardial biopsy fragments after heart transplantation: a new potential method to improve the diagnosis of rejection after heart transplantation

Inconsistencies in cardiac rejection grading systems corroborate the concept that the evaluation of inflammatory intensity and myocyte damage seems to be subjective. We studied in 36 patients the potential role of the immunohistochemical (IHC) counting of inflammatory cells in endomyocardial biopsy (EMB) as an objective tool, testing the hypothesis of correlation between the International Society for Heart and Lung Transplantation 2004 rejection and IHC counting of inflammatory cells. We observed a progressive increment in CD68+ cells/mm(2) (P = .000) and CD3+ cells/mm(2) (P = .000) with higher rejection grade. A strong correlation between the grade of cellular rejection and both CD68+ cells/mm(2) and CD3+ cells/mm(2) was obtained (P = .000). One patient with CD3+ and CD68+ cells/mm(2) above the upper limit of the 95% confidence interval for cells/mm(2) found in rejection grade 1R evolved to rejection grade 2R without treatment. In patients with 2R that did not respond to treatment the values of CD68+ or CD3+ cells were higher than the overall median values for rejection grade 2R. For diagnosis of rejection needing treatment, the CD68+ and CD3+ cells/mm(2) areas under the receiver operating characteristic curves were 0.956 and 0.934, respectively. IHC counting of mononuclear inflammatory infiltrate in EMB seems to have additive potential role in evaluation of EMB for the diagnosis and prognosis of rejection episodes.

InsCor: a simple and accurate method for risk assessment in heart surgery

BACKGROUND

Risk scores show difficulties to attain the same performance in different populations.

OBJECTIVE

To create a simple and accurate risk assessment model for patients submitted to surgery due to coronary and/or valvular disease at Instituto do Coração da Universidade de São Paulo (InCor-HCFMUSP).

METHODS

Between 2007 and 2009, 3,000 patients were submitted to surgical procedure due to coronary artery and/or valvular disease at InCor-HCFMUSP. From this record, data of 2/3 of the patients were used for model development (bootstrap technique), and 1/3 for internal validation of the model. The performance of the model (InsCor) was compared to the 2000 Bernstein-Parsonnet (2000BP) and EuroSCORE (ES) complexes.

RESULTS

Only 10 variables were selected: age > 70 years, female sex; coronary revascularization + valve, myocardial infarction < 90 days; reoperation; surgical treatment of aortic valve; surgical treatment of tricuspid valve; creatinine < 2mg/dL; ejection fraction < 30%, and events. The Hosmer Lemeshow test for the InsCor was 0.184, indicating excellent calibration. The area under the ROC curve was 0.79 for the InsCor, 0.81 for the ES and 0.82 for 2000BP, confirming that the models are good and have similar discrimination.

CONCLUSIONS

The InsCor and ES performed better than 2000BP at all stages of validation, but the new model, in addition to showing identification with the local risk factors, is simpler and more objective for mortality prediction in patients undergoing surgery due to coronary and/or valvular disease at InCor-HCFMUSP.

[Evolution of cardiovascular surgery at the Instituto do Coração: analysis of 71,305 surgeries]

BACKGROUND

Cardiovascular surgery has been undergoing transformations due to the advancement of percutaneous techniques, clinical treatment and primary prevention.

OBJECTIVE

Evaluation of incidence and mortality of heart surgeries performed at the Instituto do Coração (InCor-HCFMUSP).

METHODS

Using database from the Instituto do Coração, analysis was carried out on cardiovascular surgeries performed between 1984 and 2007, taking into consideration trends of main procedures and of mortality rates.

RESULTS

In 24 years, 71,305 heart surgeries were performed, with an annual average of 2971 procedures. The number of coronary artery bypass graft surgeries, which in the 1980s had an average of 856/year, is currently around 1.106/year. Heart valve procedures increased from 400 to 597 surgeries per year, growing 36.7%, when compared to the 1990s. Repair of congenital heart disease also had a significant increase of 50.8% in relation to the last decade. Global mortality average rate, which at baseline was 7.5%, is currently at 7.0% and 4.9% among elective procedures. In coronary artery bypass graft surgery, current average mortality rate is 4.8% and 8.5% in valve surgery. Repair of congenital heart disease accounts for 5.3%.

CONCLUSION

Cardiovascular surgery continues increasing. The coronary artery bypass graft is still the most commonly performed surgery. However, profile of procedures has been undergoing changes with the largest increase of approach to cardiac valves and congenital heart disease. Mortality rates are higher when compared to international rates, reflecting the high complexity presented in tertiary service of national reference.

Myocardial fibrosis and ventricular remodeling in severe chronic aortic regurgitation

BACKGROUND

Significant symptomatic chronic aortic regurgitation (AR) leads to considerable left ventricular remodeling at the expense of myocyte hypertrophy and extracellular matrix remodeling. The relevance of interstitial fibrosis concentration in these patients is unknown. We analyzed the degree of fibrosis in the left ventricle (LV) in symptomatic patients with AR submitted to surgical treatment, and its relationship with functional and anatomical characteristics.

OBJECTIVE

To evaluate myocardial fibrosis in chronic severe aortic regurgitation.

METHODS

Twenty-eight patients with chronic symptomatic AR (16 with normal LV function and 12 with LV dysfunction) were selected and assessed pre- and postoperatively by echocardiography. Functional capacity was measured using maximal oxygen consumption (VO2max) through the cardiopulmonary test. Myocardial fibrosis volume fraction (MFV) was quantified through endomyocardial biopsy performed in all patients during surgery. We compared the histopathologic results with a nine-patient control group.

RESULTS

The mean age was 39 +/- 12 years, 75% of the patients were male, and the rheumatic etiology accounted for 84% of the cases. Twenty-five patients remained in FC l and ll at the end of the study, and there was a significant reduction of the LV diameters between the preoperative and late postoperative timepoints. Three deaths occurred but they were not related to postoperative ventricular dysfunction. The parameters of the cardiopulmonary test were similar between pre- and postoperative timepoints. MFV in patients with AR was significantly higher than in the control group (3.47 +/- 1.9% vs 0.82 +/- 0.96%, respectively, p=0.001). There was no statistical correlation among LV fibrosis and LV diameters, LVEF and MVO2.

CONCLUSION

In patients with significant symptomatic AR, the presence of limited myocardial fibrosis was not associated with clinical, echocardiographic or functional complications.

PDIA3, HSPA5 and vimentin, proteins identified by 2-DE in the valvular tissue, are the target antigens of peripheral and heart infiltrating T cells from chronic rheumatic heart disease patients

Rheumatic fever (RF) is a post-infectious autoimmune disease due to sequel of group A streptococcus (GAS) pharyngitis. Rheumatic heart disease (RHD), the major manifestation of RF, is characterized by inflammation of heart valves and myocardium. Molecular mimicry between GAS antigens and host proteins has been shown at B and T cell level. However the identification of the autoantigens recognized by B and T cells within the inflammatory microenvironment of heart tissue in patients with RHD is still incompletely elucidated. In the present study, we used two-dimensional gel electrophoresis (2-DE) and mass spectrometry to identify valvular tissue proteins target of T cells from chronic RHD patients. We could identify three proteins recognized by heart infiltrating and peripheral T cells as protein disulfide isomerase ER-60 precursor (PDIA3), 78kD glucose-regulated protein precursor (HSPA5) and vimentin, with coverage of 45%, 43 and 34%, respectively. These proteins were recognized in a proliferation assay by peripheral and heart infiltrating T cells from RHD patients suggesting that they may be involved in the autoimmune reactions that leads to valve damage. We also observed that several other proteins isolated by 2-DE but not identified by mass spectrometry were also recognized by T cells. The identified cardiac proteins are likely relevant antigens involved in T cell-mediated autoimmune responses in RF/RHD that may contribute to the development of RHD.

Rheumatic heart disease: 15 years of clinical and immunological follow-up

Rheumatic fever (RF) is a sequel of group A streptococcal throat infection and occurs in untreated susceptible children. Rheumatic heart disease (RHD), the major sequel of RF, occurs in 30%-45% of RF patients. RF is still considered endemic in some regions of Brazil and is responsible for approximately 90% of early childhood valvular surgery in the country. In this study, we present a 15-year clinical follow-up of 25 children who underwent surgical valvular repair. Histopathological and immunological features of heart tissue lesions of RHD patients were also evaluated. The patients presented severe forms of RHD with congestive symptoms at a very young age. Many of them had surgery at the acute phase of RF. Histological analysis showed the presence of dense valvular inflammatory infiltrates and Aschoff nodules in the myocardium of 21% of acute RHD patients. Infiltrating T-cells were mainly CD4+ in heart tissue biopsies of patients with rheumatic activity. In addition, CD4+ and CD8+ infiltrating T-cell clones recognized streptococcal M peptides and cardiac tissue proteins. These findings may open the possibilities of new ways of immunotherapy. In addition, we demonstrated that the surgical procedure during acute phase of the disease improved the quality of life of young RHD patients.

Oxidant generation predominates around calcifying foci and enhances progression of aortic valve calcification

OBJECTIVE

We hypothesized that reactive oxygen species (ROS) contribute to progression of aortic valve (AV) calcification/stenosis.

METHODS AND RESULTS

We investigated ROS production and effects of antioxidants tempol and lipoic acid (LA) in calcification progression in rabbits given 0.5% cholesterol diet +10(4) IU/d Vit.D2 for 12 weeks. Superoxide and H2O2 microfluorotopography and 3-nitrotyrosine immunoreactivity showed increased signals not only in macrophages but preferentially around calcifying foci, in cells expressing osteoblast/osteoclast, but not macrophage markers. Such cells also showed increased expression of NAD(P)H oxidase subunits Nox2, p22phox, and protein disulfide isomerase. Nox4, but not Nox1 mRNA, was increased. Tempol augmented whereas LA decreased H2O2 signals. Importantly, AV calcification, assessed by echocardiography and histomorphometry, decreased 43% to 70% with LA, but increased with tempol (P < or = 0.05). Tempol further enhanced apoptosis and Nox4 expression. In human sclerotic or stenotic AV, we found analogous increases in ROS production and NAD(P)H oxidase expression around calcifying foci. An in vitro vascular smooth muscle cell (VSMC) calcification model also exhibited increased, catalase-inhibitable, calcium deposit with tempol, but not with LA.

CONCLUSIONS

Our data provide evidence that ROS, particularly hydrogen peroxide, potentiate AV calcification progression. However, tempol exhibited a paradoxical effect, exacerbating AV/vascular calcification, likely because of its induced increase in peroxide generation.

T cell response in rheumatic fever: crossreactivity between streptococcal M protein peptides and heart tissue proteins

Molecular mimicry between streptococcal and human proteins has been proposed as the triggering factor leading to autoimmunity in rheumatic fever (RF) and rheumatic heart disease (RHD). In this review we focus on the studies on genetic susceptibility markers involved in the development of RF/RHD and molecular mimicry mediated by T cell responses of RHD patients against streptococcal antigens and human tissue proteins. We identified several M protein epitopes recognized by peripheral T cells of RF/RHD patients and by heart tissue infiltrating T cell clones of severe RHD patients. The regions of the M protein preferentially recognized by human T cells were also recognized by murine T cells. By analyzing the T cell receptor (TCR) we observed that some Vbeta families detected on the periphery were oligoclonal expanded in the heart lesions. These results allowed us to confirm the major role of T cells in the development of RHD lesions.

Long-term follow up of the Biocor porcine bioprosthesis in the mitral position

BACKGROUND AND AIM OF THE STUDY

The study aim was to review the long-term results of mitral valve replacement (MVR) with the Biocor porcine bioprosthesis, in order to investigate patient survival and valve-related complications.

METHODS

Data were presented for 546 patients (320 females, 226 males; mean age 49.2 +/- 17.1 years) who underwent MVR with the Biocor porcine bioprosthesis between March 1983 and December 2000. Preoperatively, rheumatic fever was present in 42.3% of patients. Associated procedures were performed in 179 patients (32.7%), and myocardial revascularization in 54 (9.9%). Preoperatively, 41.9% of patients were in NYHA class IV. Postoperative follow up was conducted by telephone interviews, questionnaires, or examination of hospital records.

RESULTS

The hospital mortality was 9.5% (n=52); of these patients, 30 died after their first MVR and 22 after mitral reoperation. Mortality after isolated MVR was 7.6%. The total follow up was 2,148.9 patient-years, and actuarial survival was 45.0 +/- 15.8% at 15 years. Freedom from structural valve deterioration (SVD) was 51.8 +/- 13.8% for patients aged <50 years, 88.7 +/- 5.1% for those aged 51-60 years, and 84.0 +/- 9.8% for those aged 61-80 years. The incidence of prosthetic valve endocarditis was low, with 88.8 +/- 6.1% non-recurrence in 15 years. Freedom from reoperation was 33.9 +/- 10.4%, and from thromboembolism was 82.3 +/- 15.0%. Freedom from valve-related mortality was 80.7 +/- 12.5% during a 15-year period.

CONCLUSION

The 15-year clinical results with the Biocor porcine bioprosthesis in the mitral position were excellent in a young, predominantly rheumatic, patient population which, preoperatively, was in a grave clinical condition. The incidence of valve-related complications was low, as was that of SVD in patients aged >50 years.

Rheumatic fever: how S. pyogenes-primed peripheral T cells trigger heart valve lesions

The pathogenesis of rheumatic fever (RF) is related to autoimmune humoral and cellular responses against human tissues triggered by Streptococcus pyogenes. CD4(+) T cells are the ultimate effectors of chronic heart lesions in rheumatic heart disease (RHD). Heart-infiltrating CD4(+) T cell clones are able to recognize heart tissue and streptococcal antigens by molecular mimicry. The streptococcal M5(81-103) region, an immunodominant region, was recognized by both intralesional and peripheral T cell clones (62% and 38%, respectively). Peripheral T lymphocytes from Brazilian patients with severe RHD preferentially recognized the M5(81-96) peptide, in the context of HLA-DR7(+) and DR53(+) molecules. HLA-DR7 seems to be related to the development of multiple valvular lesions in RHD patients from different countries. In addition, the fact that peripheral and intralesional T cells recognized the M5(81-103) region points to this region as one of the streptococcal triggers of autoimmune reactions in RHD. T cell repertoire analysis from peripheral and intralesional T cell lines derived from RHD patients showed several oligoclonal expansions of BV families. Major expansions were found in the heart lesions, suggesting that such T cell populations preferentially migrate from the periphery to the heart. Some cross-reactive intralesional T cell clones displayed the same T cell receptor (TCR) BVBJ and CDR3 sequences, showing a degenerate pattern of antigen recognition. Heart tissue-infiltrating cells from myocardium and valvular tissue produced TNF-alpha, IFN-gamma, IL-10, and IL-4, whereas few cells from valvular tissue produced IL-4, showing that the lack of regulation in the valves could be responsible for the permanent and progressive valvular lesions.

Mimicry in recognition of cardiac myosin peptides by heart-intralesional T cell clones from rheumatic heart disease

Molecular mimicry between Streptococcus pyogenes Ags and human proteins has been considered as a mechanism leading to autoimmune reactions in rheumatic fever and rheumatic heart disease (RHD). Cardiac myosin has been shown as a putative autoantigen recognized by autoantibodies of rheumatic fever patients. We assessed the human heart-intralesional T cell response against human light meromyosin (LMM) and streptococcal M5 peptides and mitral-valve-derived proteins by proliferation assay. Cytokines induced by LMM peptides were also evaluated. The frequency of intralesional T cell clones that recognized LMM peptides was 63.2%. Thirty-four percent of T cell clones presented cross-reactivity with different patterns: 1) myosin and valve-derived proteins; 2) myosin and streptococcal M5 peptides; and 3) myosin, valve-derived proteins and M5 peptides. In addition, several LMM peptides were recognized simultaneously showing a multiple reactivity pattern of heart-infiltrating T cells. Inflammatory cytokines (IFN-gamma and TNF-alpha) were predominantly produced by heart-infiltrating T cells upon stimulation with LMM peptides. The alignment of LMM and streptococcal M5 peptides showed frequent homology among conserved amino acid substitutions. This is the first study showing the cellular response by human heart-infiltrating T cells against cardiac myosin epitopes in RHD patients. The high percentage of reactivity against cardiac myosin strengthens its role as one of the major autoantigens involved in rheumatic heart lesions. T cell reactivity toward myosin epitopes in RHD patients may also trigger the broad recognition of valvular proteins with structural or functional similarities.

Time-related distribution, risk factors and prognostic influence of embolism in patients with left-sided infective endocarditis

BACKGROUND

Few studies evaluated systemic arterial embolism after beginning of symptoms of infective endocarditis in a large series of patients.

METHODS

We studied 629 patients with left-sided infective endocarditis, aged 37.9+/-17.3 years, 396(63%) men and 233(37%) women. Endocarditis occurred on native valves in 405(64.4%) patients and on prosthetic heart valves in 224(35.6%). Infecting microorganisms were streptococci in 297(47.3%) patients, Staphylococcus aureus in 77(12.3%), Staphylococcus epidermidis in 56(8.9%), enterococci in 51(8.1%), Gram-negative bacteria in 33(5.2%), fungi in 9(1.4%) and other microorganisms in 27(4.2%). In 79(12.6%) patients blood cultures were negative.

RESULTS

146 embolic events occurred in 133(21.1%) out of 629 patients; in 63(47.4%) of them emboli affected the central nervous system, in 57(42.9%) affected peripheral organs and in 13(9.7%) affected both the central nervous system and peripheral organs. Embolism occurred between beginning of symptoms of endocarditis and antimicrobial therapy in 56(42.1%) patients and on the day therapy started in 18(13.5%); 109(81.9%) embolic events occurred up to the 15th day of antimicrobial therapy. Embolic risk was higher in S. aureus endocarditis (relative risk 2.97); in patients with a mitral (relative risk 2.4) or aortic (relative risk 3.3) prosthetic valve and vegetations on echocardiography. Embolic risk was lower in patients with a longer duration of symptoms. The death risk doubled in patients with embolism (relative risk 2.01).

CONCLUSIONS

Embolic events were more frequently early events after beginning of symptoms of infective endocarditis. Embolic risk was higher in S. aureus endocarditis and in patients with prosthetic heart valves and vegetations on echocardiography.

Comparative study of the L-hydro process and glutaraldehyde preservation

Commercial bioprosthetic heart valves are commonly preserved in glutaraldehyde and are cytotoxic to host cells, preventing spontaneous endothelialization. The aim of this study was to demonstrate the potential for in vivo endothelialization of bioprostheses treated by the L-Hydro process which consists of mild extraction of antigenic substances and incorporation of antiinflammatory and antithrombotic agents. Seven stented porcine heart valves treated by the L-Hydro process and 3 glutaraldehyde-fixed porcine heart valves were implanted in the mitral position in juvenile sheep. The valves were evaluated by echocardiography, angiography, histology, and histochemistry. No hemodynamic differences were observed, but scanning and transmission electron microscopy showed nearly complete coverage by endothelial cells of all leaflets in the L-Hydro-treated valves after 5 months of implantation. The endothelial cells were in direct contact with the underlying collagen and expressed von Willebrand-related antigens. The surfaces of the glutaraldehyde-treated valves were covered by fibrin, macrophages, calcium, and thrombotic material; only sparse endothelial cells were observed and contact with the underlying tissue was incomplete. These data indicate that L-Hydro-treated porcine valves are capable of inducing spontaneous endothelialization.

Ross procedure and ventricular septal defect correction with prolapsed cusp

We present the case of an asymptomatic 31-year-old man with perimembranous ventricular septal defect and aortic insufficiency due to a prolapsed right cusp. The ventricular septal defect was corrected with the rotation of the right cusp, and the Ross procedure was performed for the aortic insufficiency. The patient had an uneventful postoperative course. At immediate and first year follow-up examinations he presented with trivial aortic insufficiency and no residual ventricular septal defect. The patient remains asymptomatic with no medication.

Rheumatic heart disease: proinflammatory cytokines play a role in the progression and maintenance of valvular lesions

Heart lesions of rheumatic heart disease (RHD) patients contain T-cell clones that recognize heart proteins and streptococcal M peptides. To functionally characterize heart-infiltrating T lymphocytes, we evaluated their cytokine profile, both directly in situ and in T-cell lines derived from the heart (HIL). Interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 expressions were characterized in 20 heart tissue infiltrates from 14 RHD patients by immunohistochemistry. IFN-gamma-, TNF-alpha-, and IL-10-positive cells were consistently predominant, whereas IL-4 was scarce in the valves. In agreement with these data, the in vitro experiments, in which 13 HILs derived from heart samples of eight patients were stimulated with M5 protein and the immunodominant M5 (81-96) peptide, IL-4 was detected in HIL derived from the atrium (three of six) but not from the valve (zero of seven). IFN-gamma and IL-10 production were detected in culture supernatants in 11 of 13 and 6 of 12 HILs, respectively. The predominant IFN-gamma and TNF-alpha expression in the heart suggests that Th1-type cytokines could mediate RHD. Unlike in reversible myocardium inflammation, the significantly lower IL-4 expression in the valvular tissue (P = 0.02) may contribute to the progression of the RHD leading to permanent valvular damage (relative risk, 4.3; odds ratio, 15.8). The lack of IL-4 in vitro production by valve-derived HIL also emphasizes the more severe tissue destruction in valves observed in RHD.

Repeated echocardiographic examinations of patients with suspected infective endocarditis

OBJECTIVE

To study the diagnostic contribution of repeated transthoracic (TTE) and transoesophageal echocardiography (TOE) among patients with suspected infective endocarditis.

METHODS

262 patients with 266 episodes of suspected infective endocarditis were referred for TTE and TOE over three years in a 423 bed university cardiology hospital. Patients were a mean (SD) of 47.6 (17.9) years old. 139 (52.3%) episodes occurred in men and 127 (47.7%) in women. The diagnostic information obtained from repeated TTE and TOE examinations was evaluated relative to the diagnosis of endocarditis.

RESULTS

TTE examinations were repeated in 192 (72.2%) and TOE examinations were repeated in 49 (18.4%) of 266 episodes. A mean of 2.4 TTE and 1.2 TOE examinations were performed for each episode of suspected endocarditis. The second and third TTEs added diagnostic information in 34 (26.7%) and the second and third TOEs added diagnostic information in 25 (19.7%) of 127 episodes with definite endocarditis. After the third TTE or TOE no additional diagnostic information was obtained.

CONCLUSIONS

The diagnostic contribution of repeated TTE or TOE for the diagnosis of endocarditis decreased as the number of repetitions increased. In this setting, the data do not substantiate more than three TTE or TOE examinations as an efficient strategy to increase the diagnostic yield for all but selected patients with suspected endocarditis.

Achados ecocardiográficos em pacientes com suspeita diagnóstica de endocardite infecciosa

OBJECTIVE

To assess the echocardiographic findings in patients with suspected infective endocarditis.

METHODS

Two hundred sixty-two patients with suspected infective endocarditis underwent transthoracic and transesophageal echocardiographic investigation. Images of vegetations, valvular abscesses, and acute periprosthetic insufficiency were analyzed, and the correlation with clinical and laboratory data, diagnostic category, and hospital evolution was assessed.

RESULTS

The diagnosis of endocarditis was categorized as defined in 127 (47.8%) episodes, possible in 81 (30.4%), and rejected in 58 (21.8%). In patients with the defined diagnosis, the following images were identified: 135 vegetations, 37 abscesses, and 6 periprosthetic insufficiencies. Vegetations were more frequent in patients with endocarditis due to streptococci of the viridans group and enterococci (P=0.02), and with symptom duration < 10 days (P=0.001). Abscesses were more frequent in patients with symptom duration < 10 days (P=0.001). Periprosthetic insufficiency was associated with a greater need for surgical treatment (P=0.001). In patients with the possible diagnosis of endocarditis, 8 echocardiographic images considered compatible with vegetations were identified. In patients whose diagnosis of endocarditis was rejected, no vegetations, valvular abscesses, or periprosthetic insufficiencies were demonstrated.

CONCLUSION

Our echocardiographic findings varied according to the diagnostic category. The contribution to both the diagnosis and prognostic evaluation should consider the pretest probability of the diagnosis of infective endocarditis.

Duration of symptoms in patients with infective endocarditis

Despite progress in the management of infective endocarditis, delays in diagnosis or prior antimicrobial treatment may adversely influence the symptom duration and outcome. The duration of symptoms in patients with infective endocarditis was studied in 683 cases among 653 patients with 703 episodes of the disease; patients were hospitalized within 10 days of symptom onset in 169 (24.7%) cases. Antimicrobial therapy before hospital admission was administered to 257 (36.5%) patients. Overall mortality was 25.6%. Symptom duration was longer when antimicrobials were administered before diagnosis (58.8+/-78.1 vs. 44.8+/-54.9 days), when vegetations were detected on echocardiogram (53.5+/-68.2 vs. 38.8+/-47.3) and among patients admitted before 1990 (42.3+/-67.1 vs. 54.2+/-62.4 days). Symptom duration was shorter in patients with prosthetic valve endocarditis (26.8+/-34.2 vs. 59.3+/-71.6 days). In 54 (26.5%) episodes of prosthetic valve endocarditis, patients had symptoms for more than 30 days. Staphylococcus aureus was the most frequent agent among patients with symptoms up to 10 days (41.2%) and Streptococcus among those with symptoms over 20 days (53.9%). Symptom duration did not significantly differ in regard to medical (51.3+/-69.2 days) or surgical (46.7+/-55.7 days) treatment. Mortality increased as symptom duration decreased and was highest for patients who experienced symptoms for less than 10 days (36.1%). In some patients medical care may be delivered relatively late in the course of infective endocarditis. Administration of antibiotics previous to hospital admission increased duration of symptoms, and cardiac valve prosthesis, staphylococcal infection and death were associated with more acute disease.

Posterior mitral leaflet repair with a simple segmental annulus support: the 'double-Teflon technique'

BACKGROUND AND AIMS OF THE STUDY

The study aim was to present immediate and late results of a modified technique for mitral valve repair--the 'double-Teflon technique'. This consists of quadrangular resection of the posterior leaflet, annulus plication with 'pledgetted' stitches over a Teflon patch, and leaflet suture.

METHODS

Seventy-two patients (41 males, 31 females; mean age 60.5+/-11.9 years) with mitral insufficiency due to myxomatous degeneration and ruptured or elongated chordae tendineae underwent mitral valve repair with this technique. Fifteen patients (18%) had associated cardiovascular disease including coronary artery disease, aortic insufficiency, aortic stenosis and atrial septal defect. Operative, immediate postoperative and late operative echocardiographic data of the first 29 patients were analyzed. Actuarial survival was assessed using the Kaplan-Meier method.

RESULTS

There was one operative death (1%). By the late postoperative period, 95% of survivors were in NYHA functional class I. There were no episodes of hemolysis or endocarditis; the linearized rate for thromboembolism was 1.4%/patient-year. Actuarial survival at 72 months was 94.5+/-3.2%. Doppler echocardiography showed a significant decrease in mean left atrial diameter (p = 0.0001) and left ventricular diastolic diameter (p = 0.0003).

CONCLUSION

Mitral valve repair with the 'double-Teflon technique' is associated with low operative mortality, satisfactory survival rates, and good clinical outcome.