Predictive factors for requiring heart transplantation in patients with hypertrophic cardiomyopathy: data from a referral center

Background

Heart transplant (HT) remains the last treatment option for patients with non-obstructive hypertrophic cardiomyopathy (HCM) who develop end-stage heart failure (HF). Early identification of patients who may require a HT in the future is crucial in order to advise them, establish the appropriate follow-up and determine the appropriate time to include them in the waiting list.

Objectives

Our study sought to find predictive factors related with requiring HT during follow-up in patients with HCM.

Methods

Consecutive patients with HCM referred to a HCM monographic clinic from 2018 to 2020 (HCM controls) and transplanted patients due to HCM in the same tertiary HT hospital since 2003 (cases) were included. Baseline (on the date of HCM diagnosis) and longitudinal data regarding clinical, genetic, ECG and echocardiographic variables were retrospectively evaluated. Follow-up was registered from HCM diagnosis to HT (in cases) or last medical check up (controls).

Results

A total of 157 patients (24 HCM-HT cases and 133 HCM controls) were included (45±19 yo; 57% male). At the time of MCH diagnosis (Table), cases were significantly younger than controls, were more frequently symptomatic and showed significantly higher BNP levels and more advanced diastolic dysfunction (larger left atrium, higher E/A ratio and lower e'); also, HCM-HT reported more family history and had higher proportion of pathogenic mutations (being MYH7 the most frequently involved). Left ventricular (LV) systolic function was slightly reduced in HCM-HT cases. In contrast, HCM controls were more frequently diagnosed by casual findings or family screening and had more LV outflow tract obstruction at first medical evaluation. LV maximal wall thickness (MWT) did not differ between groups. During a median follow-up since HCM diagnosis of 6.2 years (median follow-up of 8.9 and 7.1 years in cases and controls, respectively), HCM-HT cases presented a higher incidence of sustained ventricular tachycardia or ICD therapy (HR=4.0; CI95%:1.6–10.0 p=0.03) and HF admissions (HR=3.9; CI95%:1.8–8.1 p<0.001). There were no cardiovascular deaths during follow-up.

Conclusions

The presence of symptoms in a young non-obstructive HCM patient, along with family history and a pathogenic mutation, should advice clinicians a closer follow-up and early transfer to a HT referral center, especially if associated with diastolic dysfunction and high BNP values.

Funding Acknowledgement

Type of funding sources: None. Table 1

Long-term follow-up of patients with Chagas cardiomyopathy living in a non-endemic area: moving towards identification of early markers of disease progression

Background

The number of patients with Chagas disease residing in Europe has increased significantly due to migration flows. Globally, Chagas cardiomyopathy has worse prognosis than other types of dilated cardiomyopathies and about 30% of patients develop cardiac involvement after a variable latency period (10–30 years). However, there is lack of data regarding the evolution of patients with Chagas disease living in a non-endemic area and potential early predictors of disease progression.

OBJETIVE

To describe the natural course of Chagas disease, the incidence rate of transformation into cardiac form and to assess if early predictors of myocardial involvement translate into a worse long-term prognosis in our non-endemic cohort.

Methods

Clinical and echocardiographic follow-up was performed in 202 individuals from endemic areas of Chagas disease. At baseline, electrocardiogram, BNP and a comprehensive echocardiography including diastolic function and longitudinal myocardial strain were performed. Four different groups were defined: healthy controls (N=77); Chagas indeterminate form (positive serology, normal ECG and left ventricle (LV) dimensions and LV ejection fraction (>50%) and no segmental abnormalities, N=92); Chagas patients with abnormal ECG but normal LV dimensions and motility (N=15); and Chagas patients with LV diameter>55 mm or LV ejection fraction<50% or segmental abnormalities (N=18). The primary clinical outcome included advanced atrioventricular block, sustained ventricular tachycardia, heart failure, heart transplant, death or progression of cardiac disease defined as LV systolic dysfunction or new segmental abnormalities. Kaplan Meier with Long rank test and Cox regression analysis was used.

Results

Mean age was 37±9 and 34% were male. Median follow-up was 69 months (range 1 to 147). The primary endpoint occurred in a total of 17 (8.4%) individuals: 5 (5.4%) in the Indeterminate group; 3 (20%) in the abnormal ECG group; and 9 (50%) in the group with abnormal LV dimension or motility, with no events among controls (long-rank test<0.01, Figure 2). Six patients evolved from the indeterminate phase to cardiac involvement (2 with isolated ECG changes and 4 with abnormal echocardiography without previous changes in ECG (Figure 1). On echocardiography, there were no differences regarding changes in LV dimensions or LV ejection fraction between Chagas patients with normal baseline echo and controls, but a significantly reduction of Em was observed (−1.6±3.0 vs. 0.2±1.0) in the former. Excluding patients with abnormal echo at baseline, BNP (HR=1.03, p=0.001), Em (HR=0.78, p=0.05) and left atrial diameter (1.23, p=0.01) were predictors of the combined event.

Conclusions

Conversion from the indeterminate to Chagas cardiomyopathy in our cohort was approximately 1.1%/year, but it may happen directly with contractility disturbances. BNP and comprehensive echocardiography may help to early detect disease progression.

Figure 1. Distribution of patients and KM curves

Funding Acknowledgement

Type of funding source: None

474 Isolated pulmonary endocarditis

INTRODUCTION

Isolated pulmonary endocarditis is a rare entity, especially in patients without predisposing factors, being its current incidence less than 1% of the total cases of infectious endocarditis. This is due to the lower right heart pressures and a decrease of intravenous drug-consum, being most of the cases nowadays, related to congenital right-heart diseases or pacemakers and defibrillators implants.

CLINICAL CASE

A 35 year-old man, tobacco smoker and intravenous cocaine consumer since he was 25, was admitted to our Emergency Department for fever up to 40ºC, cough and dyspnea started three days before admission. In the anamnesis he refereed intravenous consum of cocaine and sharing of syringes the last week. On physical examination he was tachycardic and signs of heart right failure were present such as jugular ingurgitation and peripheral edema. No murmurs were heard. No respiratory failure was detected at any time. Blood test analysis showed high levels of protein C reactive and leukocytosis. Blood cultures were positive for S. aureus (OXA-S) in the first 24h. Chest X-ray (image 1) showed a necrotizing bilateral pneumonia that was confirmed with the presence of cavitated images in the pulmonary CT (image 2). Antibiotic treatment was started with daptomicine + cloxaciline. With the suspicion of right endocarditis a transthoracic echocardiography was performed, showing the presence of a big vegetation (4x1cm) on the pulmonary valve that caused moderate pulmonary insufficiency (images 3, 4). Neither tricuspid nor left side valves were involved. Biventricular function was conserved and hyperdynamic. Endocarditis diagnosis was definitive and due to the presence of multiple right embolisms and the big size of the vegetation, the patient underwent cardiac surgery. Intra-surgical finding demonstrated a big vegetation of almost 5 cm (image 5) depending of the posterior pulmonary valve that was removed; the posterior valve needed to be repaired. Posterior clinical evolution was correct without complications, completing 17 days of i.v. antibiotics (cloxaciline) before discharge.

CONCLUSIONS

Right endocarditis is a rapidly progressive disease due to the fact that staphylococcus are the most frequent microorganisms involved. Valvular destruction and secondary embolic phenomena are the rule. Tricuspid valve is involved most of the times being the isolated pulmonary valve affection very uncommon.

Abstract 474 Figure. CT, Echo and surgical images

P1721 Reversible heart right failure. Pulmonary hypertension induced by Tyrosine Kinase Inhibitors

BACKGROUND

Pharmacologically induced pulmonary hypertension (PH) is infrequent nowadays and it is included in the type 1 of the classification of PH.

Tyrosine kinase inhibitors (TKI) are the cornerstone of the treatment of many haemotopoietic stem cell diseases. Dasatinib is a second-generation TKI used in chronic myeloid leukemia (CML) and as an infrequent cardiovascular side-effect (< 0,50%) could induce PH, usually reversible but life threatening. Only a few case series are published.

CASE DESCRIPTION: We present a 51-year-old woman who was diagnosed of a CML when she was 46. Initially, she underwent therapy with imatinib but after 5 years of treatment she developed resistance to this drug, and dasatinib was prescribed as a second line drug. After 3 months of continuous treatment, she started with dry cough and effort dyspnea. Blood analysis, EKG and Chest X-Ray were made but did not show outstanding findings. An unspecific viral infection was the final diagnosis. The patient clinical condition deteriorated with major dyspnea and edemas in the lower limbs. A TTE showed moderate tricuspid regurgitation and severe HP systolic pulmonary artery pressure (sPAP) of 80 mmHg. The pulmonary acceleration time was shortened and a mesosistolic knock was present. Systolic dysfunction of the right ventricle and pericardial effusion (image 1,2,3,4) were noted. The right atrium was not dilated. Cava vein was dilated but with inspiratory collapse >50%. The left ventricular function was preserved, but first degree diastolic dysfunction was found. Other causes of PH were excluded (types 2, 3, 4). A CT pulmonary angiogram did not show segmental perfusion defects. Finally, a right heart catheterization confirmed the TTE findings: severe precapillary PH without postcapillary component. After the diagnosis was confirmed, TKI was stopped and double targeted therapy with ambrisentan + tadalafil was started. After 6 months of treatment a new TTE was made with complete reversal of the secondary changes in the myocardium induced by the PH. No tricuspid regurgitation was detected nor any indirect sign of PH was found. (image 5,6).

CONCLUSIONS

Drug-induced PH is rare nowadays and most cases were described in the seventies in the USA related with the epidemic of anorexigenic drugs. Although the pathogenesis still remains unclear, treatment includes immediately stopping the offending agent.

Echocardiography due to its accessibility, reproducibility, consistence and low cost should be the first diagnostic tool to be considered, because as it is known, in the early stages of the disease, before developing right disfunction, clinical and conventional tests are non-specific.

Abstract P1721 Figure. Echo images: previous and afte treatment

P1810May early myocardial involvement detection in chagas disease have a prognosis impact?

Background

Brain natriuretic peptide (BNP) and novel echocardiographic techniques such as speckle-tracking and a comprehensive evaluation of diastolic function can detect early myocardial involvement in patients with Chagas disease. However, there is lack of longitudinal studies that can confirm whether this early myocardial involvement translates into a worse prognosis.

Purpose

To assess if early myocardial involvement detected by BNP or a comprehensive echocardiographic evaluation was associated with future events in Chagas disease.

Methods

182 consecutive individuals from endemic areas who underwent T. cruzi screening where prospectively included from 2007 to 2014. ECG, BNP and a comprehensive echocardiography including diastolic function and longitudinal myocardial strain were performed. Four different groups were defined: healthy controls (N=77); Chagas indeterminate form (positive serology, normal ECG and left ventricle (LV) diameter (<55 mm), LV ejection fraction (>50%) and no segmental abnormalities, N=88); Chagas patients with abnormal ECG but normal LV dimensions and motility (N=7); and Chagas patients with LV diameter>55 mm or LV ejection fraction<50% or segmental abnormalities (N=13). The primary outcome included advanced atrioventricular block, sustained ventricular tachycardia, heart failure, heart transplant or death. Kaplan Meier with Long rank test and Cox regression analysis was used.

Results

Mean age was 37±9 and 34% were male. Median follow-up was 63 months (range 1 to 137). The primary endpoint occurred in a total of 11 (10%) individuals: 2 (2.4%) in the Indeterminate group; 3 (43%) in the abnormal ECG group; and 6 (46%) in the group with abnormal LV dimension or motility, with no events among controls (long-rank test<0.01, Figure). In the global population, age, BNP, diastolic dysfunction parameters and longitudinal strain at the inferior and lateral walls were significant predictors. In the cohort of Chagas patients with normal standard echocardiography (N=92), ECG abnormalities (HR=49, p=0.001), Em (HR=0.68, p=0.03), deceleration time (HR=0.01, p=0.01), left atrial diameter (HR=1.24, p<0.01) and longitudinal strain at the midventricular lateral wall (HR=0.75, p=0.028) remained significantly associated with outcome.

Cumulative survival without events

Conclusions

Outcome was significantly more frequent in Chagas patients with abnormalities in ECG or standard echocardiography. In early forms of the disease, myocardial involvement detected by BNP or a comprehensive echocardiography was associated with prognosis, and may help to individualize treatment and follow-up.

Molecular mechanisms involved in macrophage survival, proliferation, activation or apoptosis

Macrophages play a critical role during the immune response. Like other cells of the immune system, macrophages are produced in large amounts and most of them die through apoptosis. Macrophages survive in the presence of soluble factors, such as IFN-gamma, or extracellular matrix proteins like decorin. The mechanism toward survival requires the blocking of proliferation at the G1/S boundary of the cell cycle that is mediated by the cyclin-dependent kinase (cdk) inhibitor, p27kip and the induction of a cdk inhibitor, p21waf1. At the inflammatory loci, macrophages need to proliferate or become activated in order to perform their specialized activities. Although the stimuli inducing proliferation and activation follow different intracellular pathways, both require the activation of extracellular signal-regulated kinases (ERKs) 1 and 2. However, the kinetics of ERK-1/2 activation is different and is determined by the induction of the MAP-kinase phosphatase-1 (MKP-1) that dephosphorilates ERK-1/2. This phosphatase plays a critical role in the process of proliferation versus activation of the macrophages.

Decorin inhibits macrophage colony-stimulating factor proliferation of macrophages and enhances cell survival through induction of p27(Kip1) and p21(Waf1)

Decorin is a small proteoglycan that is ubiquitous in the extracellular matrix of mammalian tissues. It has been extensively demonstrated that decorin inhibits tumor cell growth; however, no data have been reported on the effects of decorin in normal cells. Using nontransformed macrophages from bone marrow, results of this study showed that decorin inhibits macrophage colony-stimulating factor (M-CSF)-dependent proliferation by inducing blockage at the G(1) phase of the cell cycle without affecting cell viability. In addition, decorin rescues macrophages from the induction of apoptosis after growth factor withdrawal. Decorin induces the expression of the cdk inhibitors p21(Waf1) and p27(Kip1). Using macrophages from mice where these genes have been disrupted, inhibition of proliferation mediated by decorin is related to p27(Kip1) expression, whereas p21(Waf1) expression is necessary to protect macrophages from apoptosis. Decorin also inhibits M-CSF-dependent expression of MKP-1 and extends the kinetics of ERK activity, which is characteristic when macrophages become activated instead of proliferating. The effect of decorin on macrophages is not due to its interaction with epidermal growth factor or interferon-gamma receptors. Furthermore, decorin increases macrophage adhesion to the extracellular matrix, and this may be partially responsible for the expression of p27(Kip1) and the modification of ERK activity, but not for the increased cell survival.

LPS induces apoptosis in macrophages mostly through the autocrine production of TNF-alpha

The deleterious effects of lipopolysaccharide (LPS) during endotoxic shock are associated with the secretion of tumor necrosis factor (TNF) and the production of nitric oxide (NO), both predominantly released by tissue macrophages. We analyzed the mechanism by which LPS induces apoptosis in bone marrow-derived macrophages (BMDM). LPS-induced apoptosis reached a plateau at about 6 hours of stimulation, whereas the production of NO by the inducible NO-synthase (iNOS) required between 12 and 24 hours. Furthermore, LPS-induced early apoptosis was only moderately reduced in the presence of an inhibitor of iNOS or when using macrophages from iNOS -/-mice. In contrast, early apoptosis was paralleled by the rapid secretion of TNF and was almost absent in macrophages from mice deficient for one (p55) or both (p55 and p75) TNF-receptors. During the late phase of apoptosis (12-24 hours) NO significantly contributed to the death of macrophages even in the absence of TNF-receptor signaling. NO-mediated cell death, but not apoptosis induced by TNF, correlated with the induction of p53 and Bax genes. Thus, LPS-induced apoptosis results from 2 independent mechanisms: first and predominantly, through the autocrine secretion of TNF-alpha (early apoptotic events), and second, through the production of NO (late phase of apoptosis). (Blood. 2000;95:3823-3831)

The differential time-course of extracellular-regulated kinase activity correlates with the macrophage response toward proliferation or activation

Bone marrow-derived macrophages proliferate in response to specific growth factors, including macrophage colony-stimulating factor (M-CSF). When stimulated with activating factors, such as lipopolysaccharide (LPS), macrophages stop proliferating and produce proinflammatory cytokines. Although triggering opposed responses, both M-CSF and LPS induce the activation of extracellular-regulated kinases (ERKs) 1 and 2. However, the time-course of ERK activation is different; maximal activation by M-CSF and LPS occurred after 5 and 15 min of stimulation, respectively. Granulocyte/macrophage colony-stimulating factor, interleukin 3, and TPA, all of which induced macrophage proliferation, also induced ERK activity, which was maximal at 5 min poststimulation. The use of PD98059, which specifically blocks ERK 1 and 2 activation, demonstrated that ERK activity was necessary for macrophage proliferation in response to these factors. The treatment with phosphatidylcholine-specific phospholipase C (PC-PLC) inhibited macrophage proliferation, induced the expression of cytokines, and triggered a pattern of ERK activation equivalent to that induced by LPS. Moreover, PD98059 inhibited the expression of cytokines induced by LPS or PC-PLC, thus suggesting that ERK activity is also required for macrophage activation by these two agents. Activation of the JNK pathway did not discriminate between proliferative and activating stimuli. In conclusion, our results allow to correlate the differences in the time-course of ERK activity with the macrophagic response toward proliferation or activation.

Protein kinase C epsilon is required for the induction of mitogen-activated protein kinase phosphatase-1 in lipopolysaccharide-stimulated macrophages

LPS induces in bone marrow macrophages the transient expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1). Because MKP-1 plays a crucial role in the attenuation of different MAPK cascades, we were interested in the characterization of the signaling mechanisms involved in the control of MKP-1 expression in LPS-stimulated macrophages. The induction of MKP-1 was blocked by genistein, a tyrosine kinase inhibitor, and by two different protein kinase C (PKC) inhibitors (GF109203X and calphostin C). We had previously shown that bone marrow macrophages express the isoforms PKC beta I, epsilon, and zeta. Of all these, only PKC beta I and epsilon are inhibited by GF109203X. The following arguments suggest that PKC epsilon is required selectively for the induction of MKP-1 by LPS. First, in macrophages exposed to prolonged treatment with PMA, MKP-1 induction by LPS correlates with the levels of expression of PKC epsilon but not with that of PKC beta I. Second, Gö6976, an inhibitor selective for conventional PKCs, including PKC beta I, does not alter MKP-1 induction by LPS. Last, antisense oligonucleotides that block the expression of PKC epsilon, but not those selective for PKC beta I or PKC zeta, inhibit MKP-1 induction and lead to an increase of extracellular-signal regulated kinase activity during the macrophage response to LPS. Finally, in macrophages stimulated with LPS we observed significant activation of PKC epsilon. In conclusion, our results demonstrate an important role for PKC epsilon in the induction of MKP-1 and the subsequent negative control of MAPK activity in macrophages.

Adenosine inhibits macrophage colony-stimulating factor-dependent proliferation of macrophages through the induction of p27kip-1 expression

Adenosine is produced during inflammation and modulates different functional activities in macrophages. In murine bone marrow-derived macrophages, adenosine inhibits M-CSF-dependent proliferation with an IC50 of 45 microM. Only specific agonists that can activate A2B adenosine receptors such as 5'-N-ethylcarboxamidoadenosine, but not those active on A1 (N6-(R)-phenylisopropyladenosine), A2A ([p-(2-carbonylethyl)phenylethylamino]-5'-N-ethylcarboxamido adenosine), or A3 (N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide) receptors, induce the generation of cAMP and modulate macrophage proliferation. This suggests that adenosine regulates macrophage proliferation by interacting with the A2B receptor and subsequently inducing the production of cAMP. In fact, both 8-Br-cAMP (IC50 85 microM) and forskolin (IC50 7 microM) inhibit macrophage proliferation. Moreover, the inhibition of adenylyl cyclase and protein kinase A blocks the inhibitory effect of adenosine and its analogues on macrophage proliferation. Adenosine causes an arrest of macrophages at the G1 phase of the cell cycle without altering the activation of the extracellular-regulated protein kinase pathway. The treatment of macrophages with adenosine induces the expression of p27kip-1, a G1 cyclin-dependent kinase inhibitor, in a protein kinase A-dependent way. Moreover, the involvement of p27kip-1 in the adenosine inhibition of macrophage proliferation was confirmed using macrophages from mice with a disrupted p27kip-1 gene. These results demonstrate that adenosine inhibits macrophage proliferation through a mechanism that involves binding to A2B adenosine receptor, the generation of cAMP, and the induction of p27kip-1 expression.

Macrophage colony-stimulating factor induces the expression of mitogen-activated protein kinase phosphatase-1 through a protein kinase C-dependent pathway

M-CSF triggers the activation of extracellular signal-regulated protein kinases (ERK)-1/2. We show that inhibition of this pathway leads to the arrest of bone marrow macrophages at the G0/G1 phase of the cell cycle without inducing apoptosis. M-CSF induces the transient expression of mitogen-activated protein kinase phosphatase-1 (MKP-1), which correlates with the inactivation of ERK-1/2. Because the time course of ERK activation must be finely controlled to induce cell proliferation, we studied the mechanisms involved in the induction of MKP-1 by M-CSF. Activation of ERK-1/2 is not required for this event. Therefore, M-CSF activates ERK-1/2 and induces MKP-1 expression through different pathways. The use of two protein kinase C (PKC) inhibitors (GF109203X and calphostin C) revealed that M-CSF induces MKP-1 expression through a PKC-dependent pathway. We analyzed the expression of different PKC isoforms in bone marrow macrophages, and we only detected PKCbetaI, PKCepsilon, and PKCzeta. PKCzeta is not inhibited by GF109203X/calphostin C. Of the other two isoforms, PKCepsilon is the best candidate to mediate MKP-1 induction. Prolonged exposure to PMA slightly inhibits MKP-1 expression in response to M-CSF. In bone marrow macrophages, this treatment leads to a complete depletion of PKCbetaI, but only a partial down-regulation of PKCepsilon. Moreover, no translocation of PKCbetaI or PKCzeta from the cytosol to particulate fractions was detected in response to M-CSF, whereas PKCepsilon was constitutively present at the membrane and underwent significant activation in M-CSF-stimulated macrophages. In conclusion, we remark the role of PKC, probably isoform epsilon, in the negative control of ERK-1/2 through the induction of their specific phosphatase.

Interferon gamma induces the expression of p21waf-1 and arrests macrophage cell cycle, preventing induction of apoptosis

Incubation of bone marrow macrophages with lipopolysaccharide (LPS) or interferon gamma (IFN gamma) blocks macrophage proliferation. LPS treatment or M-CSF withdrawal arrests the cell cycle at early G1 and induces apoptosis. Treatment of macrophages with IFN gamma stops the cell cycle later, at the G1/S boundary, induces p21Waf1, and does not induce apoptosis. Moreover, pretreatment of macrophages with IFN gamma protects from apoptosis induced by several stimuli. Inhibition of p21Waf1 with antisense oligonucleotides or using KO mice shows that the induction of p21Waf1 by IFN gamma mediates this protection. Thus, IFN gamma makes macrophages unresponsive to apoptotic stimuli by inducing p21Waf1 and arresting the cell cycle at the G1/S boundary. Therefore, the cells of the innate immune system could only survive while they were functionally active.

Transcription factors that regulate monocyte/macrophage differentiation

Although all the cells in an organism contain the same genetic information, differences in the cell phenotype arise from the expression of lineage-specific genes. During myelopoiesis, external differentiating signals regulate the expression of a set of transcription factors. The combined action of these transcription factors subsequently determines the expression of myeloid-specific genes and the generation of monocytes and macrophages. In particular, the transcription factor PU.1 has a critical role in this process. We review the contribution of several transcription factors to the control of macrophage development.