Novel N-substituted 3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues: selective ligands for the dopamine transporter

A series of N-substituted 3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues has been prepared that function as dopamine uptake inhibitors. The N-methylated analogue of this series had a significantly higher affinity for the dopamine transporter than the parent compound, N-methyl-3 alpha- (diphenylmethoxy)tropane (benztropine, Cogentin). Yet like the parent compound, it retained high affinity for muscarinic receptors. A series of N-substituted compounds were prepared from nor-3 alpha-[bis(4'-fluorophenyl)methoxy]tropane via acylation followed by hydride reduction of the amide or by direct alkylation. All compounds containing a basic tropane nitrogen displaced [3H]WIN 35,428 at the dopamine transporter (Ki range = 8.5-634 nM) and blocked dopamine uptake (IC50 range = 10-371 nM) in rat caudate putamen, whereas ligands with a nonbasic nitrogen were virtually inactive. None of the compounds demonstrated high binding affinity at norepinephrine or serotonin transporters. Importantly, a separation of binding affinities for the dopamine transporter versus muscarinic m1 receptors was achieved by substitution of the N-methyl group with other N-alkyl or arylalkyl substituents (eg. n-butyl, allyl, benzyl, 3-phenylpropyl, etc.). Additionally, the most potent and selective analogue in this series at the dopamine transporter, N-(4"-phenyl-n-butyl)-3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogue failed to substitute for cocaine in rats trained to discriminate cocaine from saline. Potentially, new leads toward the development of a pharmacotherapeutic for cocaine abuse and other disorders affecting the dopamine transporter may be discovered.

Further studies of the reinforcing effects of benztropine analogs in rhesus monkeys

RATIONALE

Several halogenated analogs of benztropine (BZT) have previously been characterized as potent DA uptake inhibitors with behavioral profiles that indicate diminished psychomotor stimulant effects relative to cocaine. In a previous study using a fixed-ratio 10 schedule, two chloro-analogs (3'-Cl-BZT and 4'-Cl-BZT) maintained i.v. self-administration in monkeys but appeared to be weak positive reinforcers.

OBJECTIVES

The present experiments were designed to test the hypothesis that 3'-Cl-BZT and 4'-Cl-BZT are relatively weak reinforcers by evaluating reinforcing effects under increased response requirements. To examine further the effect of this halogen substitution on self-administration, 3',4"-diCl-BZT was also evaluated for reinforcing effects.

METHODS

Four rhesus monkeys self-administered cocaine (0.03 mg/kg per injection, i.v.) under a fixed-ratio 25 (FR25) schedule until stable responding was established. Saline, various doses of cocaine (0.003-0.2 mg/kg per injection), the BZT analogs (0.012-0.2 mg/kg per injection), GBR 12909 (0.012-0.2 mg/kg per injection), and compounds with known reinforcing effects (d-amphetamine, morphine, pentobarbital, ketamine) were then made available for self-administration. Various doses (0.01-0.3 mg/kg per injection) of the compounds that maintained self-administration under the FR schedule were then substituted for cocaine (0.1 mg/kg per injection) under progressive-ratio (PR) schedules.

RESULTS

Reinforcing effects were evident under the FR schedule for 3'-Cl-BZT, 4'-Cl-BZT, GBR 12909, and the control compounds, but not by 3',4"-diCl-BZT. Results with the PR suggested that the rank order of these compounds for their effectiveness as reinforcers was cocaine > GBR 12909 > 3'-Cl-BZT = 4'-Cl-BZT >> 3',4"-diCl-BZT.

CONCLUSIONS

This study confirms and extends previous results suggesting that compounds with high DAT affinity can have strong, moderate, weak, or no effectiveness as reinforcers. The mechanisms that may underlie this variation in reinforcing effectiveness of these DAT ligands remain to be established.

Highly selective chiral N-substituted 3alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues for the dopamine transporter: synthesis and comparative molecular field analysis

In a continuing effort to further characterize the role of the dopamine transporter in the pharmacological effects of cocaine, a series of chiral and achiral N-substituted analogues of 3alpha-[bis(4'-fluorophenyl)methoxy]tropane (5) has been prepared as potential selective dopamine transporter ligands. These novel compounds displaced [(3)H]WIN 35,428 binding from the dopamine transporter in rat caudate putamen with K(i) values ranging from 13. 9 to 477 nM. Previously, it was reported that 5 demonstrated a significantly higher affinity for the dopamine transporter than the parent drug, 3alpha-(diphenylmethoxy)tropane (3; benztropine). However, 5 remained nonselective over muscarinic m(1) receptors (dopamine transporter, K(i) = 11.8 nM; m(1), K(i) = 11.6 nM) which could potentially confound the interpretation of behavioral data, for this compound and other members of this series. Thus, significant effort has been directed toward developing analogues that retain high affinity at the dopamine transporter but have decreased affinity at muscarinic sites. Recently, it was discovered that by replacing the N-methyl group of 5 with the phenyl-n-butyl substituent (6) retention of high binding affinity at the dopamine transporter (K(i) = 8.51 nM) while decreasing affinity at muscarinic receptors (K(i) = 576 nM) was achieved, resulting in 68-fold selectivity. In the present series, a further improvement in the selectivity for the dopamine transporter was accomplished, with the chiral analogue (S)-N-(2-amino-3-methyl-n-butyl)-3alpha-[bis(4'-fluorophenyl)metho xy] tropane (10b) showing a 136-fold selectivity for the dopamine transporter versus muscarinic m(1) receptors (K(i) = 29.5 nM versus K(i) = 4020 nM, respectively). In addition, a comparative molecular field analysis (CoMFA) model was derived to correlate the binding affinities of all the N-substituted 3alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues that we have prepared with their 3D-structural features. The best model (q(2) = 0. 746) was used to accurately predict binding affinities of compounds in the training set and in a test set. The CoMFA coefficient contour plot for this model, which provides a visual representation of the chemical environment of the binding domain of the dopamine transporter, can now be used to design and/or predict the binding affinities of novel drugs within this class of dopamine uptake inhibitors.

Identification of small molecule binding sites within proteins using phage display technology

Affinity selection of peptides displayed on phage particles was used as the basis for mapping molecular contacts between small molecule ligands and their protein targets. Analysis of the crystal structures of complexes between proteins and small molecule ligands revealed that virtually all ligands of molecular weight 300 Da or greater have a continuous binding epitope of 5 residues or more. This observation led to the development of a technique for binding site identification which involves statistical analysis of an affinity-selected set of peptides obtained by screening of libraries of random, phage-displayed peptides against small molecules attached to solid surfaces. A random sample of the selected peptides is sequenced and used as input for a similarity scanning program which calculates cumulative similarity scores along the length of the putative receptor. Regions of the protein sequence exhibiting the highest similarity with the selected peptides proved to have a high probability of being involved in ligand binding. This technique has been employed successfully to map the contact residues in multiple known targets of the anticancer drugs paclitaxel (Taxol), docetaxel (Taxotere) and 2-methoxyestradiol and the glycosaminoglycan hyaluronan, and to identify a novel paclitaxel receptor [1]. These data corroborate the observation that the binding properties of peptides displayed on the surface of phage particles can mimic the binding properties of peptides in naturally occurring proteins. It follows directly that structural context is relatively unimportant for determining the binding properties of these disordered peptides. This technique represents a novel, rapid, high resolution method for identifying potential ligand binding sites in the absence of three-dimensional information and has the potential to greatly enhance the speed of development of novel small molecule pharmaceuticals.

Dopamine transporter binding without cocaine-like behavioral effects: synthesis and evaluation of benztropine analogs alone and in combination with cocaine in rodents

RATIONALE

Previous SAR studies demonstrated that small halogen substitutions on the diphenylether system of benztropine (BZT), such as a para-Cl group, retained high affinity at the cocaine binding site on the dopamine transporter. Despite this high affinity, the compounds generally had behavioral effects different from those of cocaine. However, compounds with meta-Cl substitutions had effects more similar to those of cocaine.

OBJECTIVES

A series of phenyl-ring analogs of benztropine (BZT) substituted with 3'-, 4'-, 3',4"- and 4',4"-position Cl-groups were synthesized and their pharmacology was evaluated in order to assess more fully the contributions to pharmacological activity of substituents in these positions.

METHODS

Compounds were synthesized and their pharmacological activity was assessed by examining radioligand binding and behavioral techniques.

RESULTS

All of the compounds displaced [3H]WIN 35,428 binding with affinities ranging from 20 to 32.5 nM. Affinities at norepinephrine ([3H]nisoxetine) and serotonin ([3H]citalopram) transporters, respectively, ranged from 259 to 5120 and 451 to 2980 nM. Each of the compounds also inhibited [3H]pirenzepine binding to muscarinic M1 receptors, with affinities ranging from 0.98 to 47.9 nM. Cocaine and the BZT analogs produced dose-related increases in locomotor activity in mice. However, maximal effects of the BZT analogs were uniformly less than those produced by cocaine, and were obtained 2-3 h after injection compared to the relatively rapid onset (within 30 min) of cocaine effects. In rats trained to discriminate i.p. saline from 29 mumol/kg cocaine (10 mg/kg), cocaine produced a dose-related increase in responding on the cocaine lever, reaching 100% at the training dose; however, none of the BZT analogs fully substituted for cocaine, with maximum cocaine responding from 20 to 69%. Despite their reduced efficacy compared to cocaine in cocaine discrimination, none of the analogs antagonized the effects of cocaine. As has been reported previously for 4'-Cl-BZT, the cocaine discriminative-stimulus effects were shifted left-ward by co-administration of the present BZT analogs.

CONCLUSIONS

The present results indicate that although the BZT analogs bind with relatively high affinity and selectivity at the dopamine transporter, their behavioral profile is distinct from that of cocaine. The present results suggest that analogs of BZT may be useful as treatments for cocaine abuse in situations in which an agonist treatment is indicated. These compounds possess features such as reduced efficacy compared to cocaine and a long duration of action that may render them particularly useful leads for the development of therapeutics for cocaine abusers.

P817 Lung ultrasound in the evaluation of pulmonary congestion in patients with aortic stenosis

Background

Aortic stenosis (AS) has a prolonged latent period, as AS worsens, the left ventricular adaptations become inadequate and impaired systolic and/or diastolic dysfunction, may lead to clinical heart failure (HF). The development of HF is an inflexion point in the natural history of AS. Pulmonary congestion is a nearly universal pathophysiological finding in HF, and may precede symptoms. Lung ultrasound (LUS) evaluation of B-lines has been proposed as a simple, non-invasive tool to assess pulmonary interstitial edema.

Aim

To assess pulmonary interstitial edema with LUS in patients with moderate and severe aortic stenosis, to define performance of LUS compared with clinical assessment and echocardiographic parameters.

Methods

Sixty-eight consecutive patients (36 women, mean age 74 ± 9 years) with moderate or severe aortic stenosis were enrolled. Exclusion criteria were as follows: moderate or severe aortic regurgitation, moderate or severe mitral regurgitation, cardiomyopathies and pulmonary disease. All patients underwent comprehensive echocardiography examination and LUS according to a previously validated 28 scanning-site assessment.

Results

we found a significant number of B-lines (≥15) in 79% of patients. B-lines were positively correlated with left atrial volume index (p < 0,05, r = 0,3) and estimated pulmonary pressure ( p < 0,0001, r= 0,62 Figure 1.) The number of B-lines didn’t correlate with the severity of AS (mean gradient vs. B-lines: p = 0,2, valve area vs. B-lines: p = 0,2.), however properly reflects different functional status of the patients (p < 0,0001, Figure 2.)

Conclusion

Lung ultrasound is a promising tool to detect lung congestion related to AS. The severity of congestion doesn’t correlate with the severity of AS, albeit B-lines better reflect the deteriorating functional status of the patients and the haemodynamic consequences related to AS.

Abstract P817 Figure. Correlation PASP vs Blines, NYHA/B-lines

Simple and additive diagnostic modalities for the screening of heart failure with preserved ejection fraction

Background

Nearly half of all patients with heart failure (HF) symptoms have an EF that is preserved (HFpEF). The prevalence of HFpEF is rising, with high morbidity, mortality. The diagnosis of HFpEF is particularly challenging. Lung ultrasound (LUS) and left atrial strain are promising screening and diagnostic tools to assess pulmonary congestion and left atrial dysfunction in patients with suspected HFpEF.

Aim

To evaluate the relationship between patients symptoms, pro-BNP level with LUS and left atrial strain, as well to assess the diagnostic power of B-lines in HFpEF population.

Methods

82 consecutive patients (57 women, mean age 70±6 years) with clinical signs of heart failure were prospectively enrolled. Exclusion criteria were: ejection fraction <55%, more than mild mitral and/or aortic valve disease, pulmonary disease, pulmonary arterial hypertension. Within one hour all patients underwent comprehensive echocardiographic evaluation including left atrial strain analysis (peak atrial longitudinal strain-LASr), lung ultrasound assessment of B-lines on the anterolateral and posterior chest wall, and NT-proBNP levels.

Results

In 45 patients (54%) a significant number of B-lines (≥15) were observed. We found a positive correlation between the number of B-lines and NT-proBNP levels (p<0.0001, r=0.67), left atrial volume (p<0.0001, r=0.45), and LASr (p<0.005, r=−0.4). We also found week correlation between the number of B-lines and E/e' ratio (p<0.003, r=0.3), and between E/e' ratio and NT-proBNP level (p<0.05, r=0.2). We also assessed the diagnostic ability of B-lines to predict markedly elevated pro-BNP level (≥125pg/ml), AUC was 0.85, with specificity of 64% and sensitivity of 85% (Figure 1). The number of B lines also correlated with the H2FPEF score (p<0.001, r=0.4).

Conclusion

LUS is a simple, feasible tool to detect pulmonary congestion in HFpEF and it has an adequate diagnostic power to predict elevated NTpro-BNP level. LASr is promising too, which better reflects pulmonary congestion and elevated NT-proBNP values than the conventional echocardiographic parameters.

Figure 1. ROC curve Blines predict high NTproBNP

Funding Acknowledgement

Type of funding source: None

P944 From systolic pulmonary arterial pressure to pulmonary vascular resistance and reserve: a simplified method for exercise stress echocardiography

OnBehalf

On behalf of Stress Echo 2020 study group of the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI).

Background

The potential of exercise stress echocardiography (ESE) seems to be still underused especialy in the assessment of pulmonary hemodynamics.

Aim

To assess the feasibility and compare pulmonary vascular resistance (PVResistance) and reserve (PVReserve) during ESE in patients at risk of pulmonary hypertension (PH) and controls.

Methods

We performed semi-supine ESE, in 97 subjects (age 49 ± 16 yrs, 63 females): 58 patients (Group 1) at risk for PH (systemic sclerosis and other connective tissue diseases) and 39 healthy controls (Group 2). Rest and stress assessment included: tricuspid regurgitant velocity (TRV), pulmonary acceleration time (ACT), cardiac output (CO), SPAP estimation with Bernouilli equation or from ACT with formula: log10 SPAP= - 0.004 (ACT) + 2.1. We estimated PVResistance from Abbas formula, and PVReserve as ΔCO/ ΔSPAP or (when CO was not available) as minutes of exercise/ΔSPAP. When ΔSPAP was <10 mmHg, it was considered equal to 1.

Results

With TRV or ACT to estimate pressures, and cardiac output or its proxy to estimate flow, PVResistance or PVReserve could be measured in all patients. At peak exercise, PVResistance was higher and PVReserve lower in Group 1 : see Table.

Conclusion

Estimation of PVResistance and/or PVReserve can be obtained in all patients during ESE, integrating TRV with ACT, and using exercise-time as a proxy of CO when the latter is not available. These indices may be useful for a better, noninvasive characterization of the heterogeneity of pulmonary hemodynamics.

Pulmonary hemodynamics ESE data Parameter Group 1, PH (n = 58) Group 2, normals (n = 39) P value TRV rest (cm/s) 243 ± 63 204 ± 31 =0.0147 TRV peak (cm/s) 344 ± 68 204 ± 53 <0.0001 ACT rest (ms) 113 ± 33 128 ± 20 =0.0205 ACT peak (ms) 86 ± 19 94 ± 22 ns SPAP rest (mm Hg) 26 ± 10 21 ± 4 =0.0039 SPAP peak (mm Hg) 45 ± 19 28 ± 13 <0.0001 CO rest (mL/min) 4.9 ± 1.7 5.1 ± 1.7 ns CO peak (mL/min) 7.8 ± 2.8 7.6 ± 2.9 ns Exercise time (min) 7 ± 2 13 ± 3 <0.0001 PVResistance (WU) rest 1.63 ± 0.52 1.54 ± 0.34 ns PVResistance (WU) peak 2.01 ± 0.89 1.27 ± 0.42 =0.0219 PVReserve (ΔCO/ΔSPAP) 1.38 ± 1.13 3.55 ± 2.45 =0.001 PVReserve (Extime/ΔSPAP) 4.69 ± 2.67 10.96 ± 4.39 <0.0001 Legends: WU -Wood Unit, Ex time - exercise time

P1586 Lung ultrasound and left atrial deformation analysis: a promising methods for the diagnosis of heart failure with preserved ejection fraction

Background

Heart Failure with Preserved Ejection Fraction (HFpEF) is a growing healthcare burden and its prevalence is increasing. Diagnosing HFpEF is challenging. Lung ultrasound (LUS) and left atrial strain are promising screening tools to assess pulmonary congestion and left atrial dysfunction in patients with suspected HFpEF.

Aim

To evaluate the relationship between LUS, left atrial strain and NT-proBNP level in patients with HFpEF. Also to assess the diagnostic power of B-lines in HFpEF population.

Methods

Forty-seven consecutive patients (24 women, mean age 69 ± 11 years) with clinical signs of heart failure were prospectively enrolled. Exclusion criteria were: ejection fraction <55%, more than mild mitral and/or aortic valve disease, pulmonary disease, pulmonary arterial hypertension. Within one hour all patients underwent comprehensive echocardiographic evaluation including left atrial strain analysis (peak atrial longitudinal strain-PALS), lung ultrasound assessment of B-lines on the antero-lateral and posterior chest wall, and NT-proBNP levels.

Results

In 34 patients (72%) a significant number of B-lines (≥15) were observed. We found a positive correlation between the number of B-lines and NT-proBNP levels (p < 0,0001, r = 0,74, Figure 1.), left atrial volume (p < 0,05, r = 0,45), and PALS (p < 0,02, r = 0,4 ). We didn’t found any correlation between the number of B-lines and E/e’ ratio (p = 0,1, r = 0,28), or between E/e’ ratio and NT-proBNP level (p = 0,1, r = 0,2). We also assessed the diagnostic ability of ≥15 B-lines to predict markedly elevated pro-BNP level (≥ 220pg/ml), AUC was 0.89. If the total number of B-lines was greater or equal to 28, the sensitivity was 68% with the specificity of 100%, but if we changed the cut-off value to 12, the sensitivity grew to 89% with the specificity of 71%. (Figure 2.).

Conclusion

LUS is a simple, feasible tool to detect pulmonary congestion in HFpEF and it has a strong diagnostic power to predict elevated NTpro-BNP level. B-lines correlate with parameters of left atrial dysfunction. PALS is promising too, which better reflects pulmonary congestion and elevated NT-proBNP values than the conventional echocardiographic parameter E/e’.

Abstract P1586 Figure. NT-pBNP vs B-lines, AUC of Blines

Assessment of pulmonary circulation unit during exercise in patients with ankylosing spondilitis and sporiatic arthritis

Funding Acknowledgements

Type of funding sources: None.

Background  Ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are chronic multisystem inflammatory disorders that present with articular and extra-articular features. Cardiac dysfunction and pulmonary disease are well-known and commonly reported extra-articular manifestations of AS and PsA.  The inflammatory process can induce respiratory complications, including chest wall restriction, significantly impacting patients" cardiorespiratory status.

We aimed to assess pulmonary circulation and right ventricle behaviour during exercise in patients with AS and PsA and to detect the possible effect of chest wall restriction on right heart function.

Methods  A total of 45 spondylarthritis patients were enrolled in the study (age 51.5 ± 12.3 years, 82.2% men): 27 of them were diagnosed with AS (20 of them had ankylosis at the time of the study), while 18 had PsA (2 of them in ankylosis). According to a standardized protocol, all subjects underwent resting and exercise stress echocardiography on a semi-recumbent cycle ergometer with an incremental workload up to the maximal tolerated workload. Basic echocardiographic measurements were taken, focusing on the right and left ventricular functions and the systolic pulmonary artery pressure (PASP) at rest, at 50 watts workload, and maximal exercise. During the examination, non-invasive blood pressure measurements, transcutaneous capillary oxygen saturation and continuous ECG recording were performed. 

Results PASP did not differ between the AS and PsA patients at rest (15.6 ± 6.7 mmHg vs 13.7 ± 8.3 mmHg; p = ns); however, PASP measured at the maximal workload was significantly higher among AS patients  (31.4 ± 15.9mmHg vs 21.6 ± 12.7mmHg; p < 0.05; Figure 1). PASP did not correlate with the age or the time that passed since the diagnosis. Parameters describing the left and right ventricular systolic and diastolic function did not differ significantly between AS and PsA patients at rest and peak stress. Comparing the LV diastolic parameters of ankylosing patients with non-ankylosing patients irrespective of the underlying disease showed significantly different values in peak E/e"ratio (8.9 ± 3 vs 7.4 ± 1.6; p < 0,05; Figure 2).

Conclusion  Exercise stress echocardiography is a promising diagnostic modality in autoimmune diseases. In AS patients, the chest wall restriction may results in elevation of PASP during the exercise. The noninvasive indice of left ventricular filling pressure increases significantly in patients with ankylosis in both groups, explaining the effect of the rigid chest wall on the left ventricular filling. Abstract Figure.  Abstract Figure.

P1481B-lines and left atrial strain in outpatients with suspected heart failure with preserved ejection fraction

Background

Heart Failure with Preserved Ejection Fraction (HFpEF) is a growing healthcare burden and its prevalence is increasing. Diagnosing HFpEF is challenging. Lung ultrasound (LUS) and left atrial strain are promising tools to assess pulmonary congestion and left atrial dysfunction in outpatient settings in patients with suspected HFpEF.

Aim

To evaluate the correlation of LUS B-lines with left atrial strain in patients with HFpEF.

Methods

Thirty-six consecutive patients (24 women, mean age 70±6 years) with clinical signs of heart failure were prospectively enrolled. Exclusion criteria were: ejection fraction <55%, more than mild mitral and/or aortic valve disease, pulmonary disease, pulmonary arterial hypertension. Within one hour all patients underwent comprehensive echocardiographic evaluation including left atrial strain analysis (peak atrial longitudinal strain-PALS), lung ultrasound assessment of B-lines on the antero-lateral and posterior chest wall, and NT-proBNP levels.

Results

The mean ejection fraction was 65.5±8.6%. In 28 patients (85%) a significant number of B-lines (≥15) was observed. We found a positive correlation between the number of B-lines and NT-proBNP levels (p<0.0001, r: 0.76, Figure 1.), left atrial volume (p<0.05, r: 0.45), and PALS (p<0.05, r: −0.5, Figure 2.). We didn't found any correlation between the number of B-lines and E/e'ratio (p=0.1, r: 0.28), or between E/e' ratio and NT-proBNP level (p=0.2, r: 0.2).

Conclusion

LUS is a simple, feasible tool to detect pulmonary congestion in HFpEF and it seems to better characterize these patients. B-lines correlate well with NT-proBNP values and with parameters of left atrial dysfunction. PALS is a promising too which better reflects pulmonary congestion and elevated NT-proBNP values than the conventional echocardiographic parameter E/e'.

The prognostic value of B-lines in heart failure with preserved ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

 Heart Failure with Preserved Ejection Fraction (HFpEF) is a growing healthcare burden, and its prevalence is steadily increasing. Despite its common occurrence, HFpEF remained a challenge in every aspect. The evaluation of B-lines with lung ultrasound (LUS) is a promising diagnostic and prognostic tool in this population.

Objectives

The aim of our study was to assess the diagnostic and prognostic performance of B-lines compared with traditional clinical, echocardiographic parameters and natriuretic peptide levels in patients with clinical suspicion of HFpEF.

Methods

78 consecutive patients (70.45 ± 6.75 years, 72% female) with suspected HFpEF were prospectively enrolled. Exclusion criteria were: ejection fraction ≤55%, more than mild mitral and/or aortic valve disease, cardiomyopathy, pulmonary disease, pulmonary arterial hypertension, renal failure and anemia. All patients underwent comprehensive echocardiography, lung ultrasound exam and NT-proBNP measurement during their first appointment. Our endpoint was a composite of acute heart failure (HF),  hospitalization for the worsening HF symptoms and intensification of diuretic therapy. Also, traditional major cardiac adverse events such as death, myocardial infarction, stroke and revascularization were collected.

Results

We detected 11 events during 12 ± 6 months follow up. The number of B-lines showed a good correlation with NT-proBNP levels (p &lt; 0,001, r = 0.693). B-lines were found to have similar performance to NT-proBNP in predicting events (AUC = 0.778 vs. 0.770, respectively). Those who had more than 30 B-lines on LUS had significantly worse event-free survival p = 0.004. Having more than 30 B-lines at baseline was associated with 7 times greater hazard of adverse outcomes.

Conclusions

LUS is a simple, feasible tool to detect pulmonary congestion in patients with HFpEF. In our prospective cohort study, LUS was found to be a useful tool for prognostic stratification.

Abstract Figure. Prognostic value of B-lines

Assessment of the right ventricular-pulmonary circulation unit during stress in ankylosing spondylitis and psoriatic arthritis patients

Background

Cardiopulmonary complications are common in ankylosing spondylitis (AS) and arthritis psoriatica (APs), which have an unfavourable impact on mortality and quality of life. APs may be connected with pulmonary hypertension, while AS is linked to interstitial lung disease and chest wall restriction.

We aimed to assess the response of the pulmonary circulation unit during stress in AS and APs patients.

Methods

A total of 71 patients were enrolled in the study: 28 of them had AS (age 50.8±11.8 years), 17 APs (age 52.1±13.5 years), and 26 were healthy individuals (age 54.23±9.9 years). To the maximally tolerated workload, all subjects underwent resting and exercise stress echocardiography on a supine bicycle ergometer. Echocardiographic measurements were taken at rest, at 50 watts workload, and at maximal exercise.

Results

AS patients had significantly higher pulmonary artery systolic pressure (PASP; AS: 32.6±16.8 mmHg, APs: 21.6±12.7 mmHg, p&lt;0.05) and pulmonary vascular resistance (PVR; AS: 1.3±0.4 WU, PsA: 1.1±0.3 WU, p&lt;0.05) at maximal workload, while the right ventricular-pulmonary arterial (RV-PA) coupling at peak stress was higher in APs patients (AS: 1.2±0.6 mm/mmHg, PsA: 1.8±1.1 mm/mmHg, p&lt;0.05). Comparing to the control group, AS and PsA patients had significantly higher resting PASP (control: 12.6±6.4 mmHg; AS: 22.8±7.6 mmHg, p&lt;0.001; PsA: 21.4±7.0 mmHg, p&lt;0.001), lower resting RV-PA coupling (control: 2.7±1.4 mm/mmHg; AS: 1.3±0.4, p&lt;0.001; PsA 1.3±0.4 mm/mmHg, p&lt;0.001), and higher peak PVR (control: 0.6±0.4 WU; AS: 1.3±0.4, p&lt;0.001; PsA: 1.1±0.3 WU, p&lt;0.005). One-way analysis of variance of the three groups also showed significant differencies in the resting PASP (p&lt;0.001), peak PASP (p&lt;0.05), resting RV-PA coupling (p&lt;0.001), peak PVR (p&lt;0.001).

Conclusion

Stress echocardiography is a promising, radiation-free method for assessing the subclinical cardiopulmonary changes among AS and PsA patients. The changes of PVR during stress may highlight the pulmonary complications in the subclinical stage.

Funding Acknowledgement

Type of funding sources: None.

Novel benztropine [3a-(diphenylmethoxy)tropane] analogs as probes for the dopamine transporter

The design, synthesis and pharmacological evaluation of novel dopamine transporter ligands, based on Benztropine [3a-(diphenylmethoxy) tropane], has been a focus of our research efforts toward the development of novel cocaine-abuse pharmacotherapeutics. Structure-activity relationships at the dopamine transporter, for this series of compounds, have been derived and compared to those of cocaine and GBR 12909. These studies suggest that structurally diverse dopamine uptake inhibitors may access different binding domains on the dopamine transporter. The distinctive behavioral profile displayed in this series of compounds, as compared to cocaine and other dopamine uptake inhibitors, is of particular interest and is proposed to be relevant to the pharmacodynamic and pharmacokinetic properties of this class of tropane-based molecules.

Left atrial volume changes during exercise stress echocardiography in heart failure and hypertrophic cardiomyopathy

Background

Left atrial volume (LAV) may dilate acutely during exercise stress echocardiography (ESE) in chronic coronary syndromes.

Purpose

To assess the feasibility and functional correlates of LAV during ESE outside coronary artery disease.

Methods

We performed ESE (semi-supine bike in 159 or treadmill in 105 patients) in 264 patients (155 male, age 58±15 years) with heart failure with preserved ejection fraction (HFpEF, n=82), heart failure with reduced ejection fraction (HFrEF, n=51) or hypertrophic cardiomyopathy (HCM, n=131). LAV was measured with the biplane disk summation method. LAV-dilators were defined as those with stress-rest increase in LAV index ≥6.8 ml/m2, a cutoff derived from a calculated reference change value above the biological, analytical and observer variability of LAV. Average E/e', mitral regurgitation (MR, graded from 0 = absent to 3 = severe), left ventricular ejection fraction, systolic pulmonary arterial pressure (SPAP) from tricuspid regurgitant jet velocity and B-lines (4-sites simplified scan) were also measured.

Results

Measurement success rate was 264/264 (100%) in technically adequate images. At group analysis LAV changes during ESE were heterogeneous, with LAV index increase in HFrEF (rest = 41±26 vs stress = 44±27 ml/m2, p=0.563) and HCM (rest = 39±18 vs stress = 41±17 ml/m2, p=0.444) and mild decrease in HFpEF (rest= 28±12 vs stress = 26±11 ml/m2, p=0.020). At individual patient analysis, LAV dilation occurred in 88 (33%) patients: 9 with HFpEF (11%), 24 with HFrEF (47%), 55 with HCM (42%, p&lt;0.001 vs HFpEF). Prevalence of LAV dilation was 33/105 with treadmill and 55/159 with semi-supine ESE (31 vs 35%, p=0.588). In the overall population, LAV stress-rest change was directly related to stress SPAP (r=0.264, p=0.001), peak E/e'(r=0.288, p&lt;0.001), stress B-lines (r=0.223, p=0.003) and peak MR grade (r=0.295, p&lt;0.0001). LAV-dilators more frequently showed abnormal values of SPAP, B-lines, MR and E/e'during ESE compared to non-dilators (see figure).

Conclusion

LAV assessment during ESE is feasible with high success rate, and LAV dilation is equally frequent with upright treadmill or semi-supine bike exercise. LAV individual response to stress is unpredictable, with a significant dilation occurring more frequently in HCM and HFrEF compared to HFpEF patients. Across all conditions, LAV dilation is correlated to more advanced pulmonary and hemodynamic congestion, higher left ventricular filling pressures and more severe MR during stress.

Funding Acknowledgement

Type of funding sources: None. LAV dilators vs non-dilators comparison. SPAP value ≥40 mm Hg; E/e' ≥15; MR grade ≥2; B-lines &gt;10 in patients with (blue bars) and without (red bars) LAV dilation.

Left atrial volume stress echocardiography in chronic coronary syndromes

Background

An enlarged left atrial volume index (LAVI) at rest mirrors increased LA pressure and/or impairment of LA function. A cardiovascular stress may acutely modify LAVI within minutes.

Purpose

To assess the feasibility and functional correlates of LAVI-stress echocardiography (SE)

Methods

Out of 514 subjects referred to 10 quality-controlled labs, LAVI-SE was completed in 490 (359 male, age 67±12 yrs, ejection fraction 60±10%) with suspected or known chronic coronary syndromes (n=462) or asymptomatic controls (n=28). The utilized stress was exercise in 177, vasodilator in 167, dobutamine in 146. LAVI was measured with the biplane disk summation method. SE was performed with the ABCDE protocol. In a single center sub-study in 50 subjects, including 28 controls and 22 patients, also peak longitudinal atrial strain (PALS, %) was measured as an index of LA reservoir function.

Results

The intra-observer and inter-observer LAVI variability were 5% and 8%, respectively. Δ-LAVI changes (stress-rest) were negatively correlated with resting LAVI (r=−0.271, p&lt;0.001), heart rate reserve (r=−0.239, p&lt;0.001), and Δ-PALS (n=50, r=−0.374, p=0.007).LAVI-dilators were defined as those with stress-rest increase ≥6.8 ml/m2, a cutoff derived from a calculated reference change value above the biological, analytical and observer variability of LAVI. LAVI dilation (see figure) occurred in 56 patients (11%). At multivariable logistic regression analysis, B-lines ≥2 (OR: 2.586, 95% CI =1.1293–5.169, p=0.007) and abnormal left ventricular contractile reserve (OR: 2.207, 95% CI=1.111–4.386, p=0.024) were associated with LAVI dilation.

Conclusion

LAVI-SE is feasible, with high success rate and low variability, in patients with chronic coronary syndromes. A wet (increased B-lines) and weak (reduced LV contractile reserve and LA reservoir function) heart frequently portends LAVI dilation during stress.

Figure 1

Funding Acknowledgement

Type of funding source: None

Pulmonary congestion during exercise stress echocardiography in ischaemic, heart failure and valvular patients

Background

Lung ultrasound (LUS) detects pulmonary congestion as B-lines at rest and exercise stress echocardiography (ESE).

Aim

To assess the prevalence of B-lines during ESE in different cardiovascular diseases.

Methods

We performed ESE plus LUS (4-site simplified scan) in 4419 subjects referred for semi-supine bike ESE in 28 certified centers. B-lines score ranged from 0 (normal) to 40 (severely abnormal). Stress B-lines abnormal result was ≥2 units. Six different populations were evaluated: healthy controls (n=103); chronic coronary syndromes (CCS, n=3701); heart failure with reduced ejection fraction (HFrEF, n=395); heart failure with preserved ejection fraction (HFpEF, n=70); valvular heart disease (VHD) for ischemic mitral regurgitation ≥moderate at rest (n=123); repaired tetralogy of Fallot (ToF, n=27).

Results

Feasibility of B-lines was 100% at rest and peak ESE in all subjects. Imaging and analysis time were &lt;1 minute. B-lines (median) were not detectable in healthy subjects (rest=0.1 [0–1] vs 0.1 [0–1], p=ns) and TOF (rest=0.2 [0–2] vs 0.3 [0–4], p=ns), but were present in all other groups: see figure. During ESE, B-lines increased in CCS (rest=0.5 [0–24] vs ESE=1.3 [0–28], p&lt;0.001); HFrEF (rest=1.4 [0–35] vs ESE=2.9 [0–40], p&lt;0.001); HFpEF (rest=0.3 [0–2] vs ESE=3.4 [0–12], p&lt;0.001), VHD (rest=1.7 [0–12] vs ESE=4.3 [0–23], p&lt;0.001). Stress B-lines were correlated with stress-rest change in wall motion score index in CCS (r=0.325, p&lt;0.001), contractile reserve in HFrEF (r=−0.266, p&lt;0.001) and in VHD (r=−.0300, p=0.001), left atrial volume stress-rest change in HFpEF (r=0.287, p=0.043).

Conclusion

B-lines identify the pulmonary congestion phenotype at rest and more frequently during ESE in patients with different coronary, myocardial or valvular heart disease, all sharing the final common pathway of acute backward left heart failure through different disease-specific mechanisms. B-lines are absent in healthy subjects and in conditions inducing a mostly right-sided overload such as repaired ToF.

Funding Acknowledgement

Type of funding sources: None. Figure 1. B-lines at rest and during stress. Percentage (%) of rest (empty bar) and stress (full bar) B-lines abnormality (≥2 units) in six different study groups.

Differential binding of tropane-based photoaffinity ligands on the dopamine transporter

Benztropine and its analogs are tropane ring-containing dopamine uptake inhibitors that produce behavioral effects markedly different from cocaine and other dopamine transporter blockers. We investigated the benztropine binding site on dopamine transporters by covalently attaching a benztropine-based photoaffinity ligand, [125I]N-[n-butyl-4-(4"'-azido-3"'-iodophenyl)]-4', 4"-difluoro-3alpha-(diphenylmethoxy)tropane ([125I]GA II 34), to the protein, followed by proteolytic and immunological peptide mapping. The maps were compared with those obtained for dopamine transporters photoaffinity labeled with a GBR 12935 analog, [125I]1-[2-(diphenylmethoxy)ethyl]-4-[2-(4-azido-3-iodophenyl)ethy l]p iperazine ([125I]DEEP), and a cocaine analog, [125I]3beta-(p-chlorophenyl)tropane-2beta-carboxylic acid, 4'-azido-3'-iodophenylethyl ester ([125I]RTI 82), which have been shown previously to interact with different regions of the primary sequence of the protein. [125I]GA II 34 became incorporated in a membrane-bound, 14 kDa fragment predicted to contain transmembrane domains 1 and 2. This is the same region of the protein that binds [125I]DEEP, whereas the binding site for [125I]RTI 82 occurs closer to the C terminal in a domain containing transmembrane helices 4-7. Thus, although benztropine and cocaine both contain tropane rings, their binding sites are distinct, suggesting that dopamine transport inhibition may occur by different mechanisms. These results support previously derived structure-activity relationships suggesting that benztropine and cocaine analogs bind to different domains on the dopamine transporter. These differing molecular interactions may lead to the distinctive behavioral profiles of these compounds in animal models of drug abuse and indicate promise for the development of benztropine-based molecules for cocaine substitution therapies.

Comprehensive diastolic exercise stress echocardiography in heart failure with preserved ejection fraction

Background

In heart failure with preserved ejection fraction (HFpEF), diastolic exercise stress echocardiography (ESE) is currently recommended with E/e' and systolic pulmonary artery pressure (SPAP) from tricuspid regurgitant jet velocity (TRV).

Purpose

To evaluate conventional and advanced ESE parameters in patients with HFpEF.

Methods

We prospectively screened 124 patients with suspected HFpEF (dyspnea, resting EF &gt;50%, increased natriuretic peptide levels) and HFA-PEFF score ≥1. Of these 124, 10 patients were excluded for history of coronary artery disease, 3 for severe mitral regurgitation (MR), 12 for inducible ischemia. The final study population consisted of 99 patients (mean age 63±7 yrs, 57 females). All underwent ESE, with semi-supine bike (n=35), upright bike (n=20) or treadmill (n=44 patients) in 11 accredited labs from 9 countries (Argentina, Brazil, Bulgaria, Hungary, Italy, Lithuania, Mexico, Russia and Spain). In addition to E/e' average (abnormal stress response ≥15 units) and TRV (abnormal stress response &gt;3.4 m/s), we measured 8 additional criteria: B-lines (4-site simplified scan, abnormal stress value ≥2); cardiac index (CI) reserve (increase from rest to stress, abnormal &lt;1.63 l/min/m2), ejection fraction (EF, abnormal increase &lt;5%), global longitudinal strain (GLS, abnormal increase &lt;2%), end-diastolic volume (EDV, abnormal stress &lt; rest); heart rate reserve (HRR, abnormal &lt;1.80); left atrial volume index, (LAVI, abnormal increase &gt;6.8 ml/m2); MR (abnormal, stress value more than mild).

Results

Technical success rate during stress ranged from 100% for B-lines to 75% for GLS: see Table. At individual criteria analysis, positivity rate in interpretable studies ranged from 67% of HRR to 10% of peak MR: see table. At individual patient analysis, an abnormal response in 1 ESE criterion occurred in 4 pts (4%), of 2 to 4 criteria in 71 pts (72%) and of ≥5 criteria in 24 (24%).

Conclusion

In suspected HFpEF, ESE is helpful in the screening phase to identify extra-diastolic causes of dyspnea such as myocardial ischemia or severe MR. In the diagnostic phase, a comprehensive ESE captures the functional heterogeneity of HFpEF, with variable association of multiple phenotypes, the most frequent represented by reduced chronotropic, cardiac or contractile reserve and pulmonary congestion.

Funding Acknowledgement

Type of funding sources: None.

Cardiac remodeling accompanied by increased arrhythmia susceptibility in a dog model of chronic high-intensity endurance training

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by NKFIH grants (K-19992, K-135464) and GINOP-2.3.2-15-2016-00047.

Background

Despite the cardiovascular benefits of regular physical exercise, chronic high-level exercise can evoke malignant arrhythmias, including ventricular fibrillation and even sudden cardiac death, especially in young top athletes. In some cases the underlying mechanisms are unclear.

Objectives

The goal of this study was to assess mechanisms underlying cardiac structural-electrical changes and arrhythmia vulnerability by high-level vigorous exercise training in animal species that are electrophysiologically relevant to the human heart.

Methods

Beagle dogs were randomly assigned to matched sedentary (Sed) or intensive exercise-training (Ex) groups (n=12-12). Ex dogs underwent a 4-month-long intensive treadmill-running protocol (5 days a week, 6 hours a day at a speed of 14-21 km/h with an inclination from 5% to 12%). In vivo echocardiography and electrophysiological measurements were performed. Proarrhythmic sensitivity was tested and the autonomic alterations were examined. At study end, arrhythmia susceptibility was tested with high-frequency burst stimulation in open-chest anaesthetized dogs. This was followed by cardiac excision and cardiomyocyte isolation, formalin preservation for histology, snap-freezing in liquid nitrogen for molecular biology.

Results

The vigorous endurance training was resulted in increased left ventricular end-diastolic diameter, increased septal wall thickness and greater left ventricular mass index (Ex vs. Sed: 98±12 vs. 136±7 g/m2, p&lt;0.05). Some degree of enhanced fibrosis was observed. Endurance training decreased heart rate both in whole animal and in vitro dog experiments. ECG recordings presented enhanced heart rate variability parameters, prolonged PQ (Ex vs. Sed: 98.3±2.9 vs. 116.7±3.6 ms, p&lt;0.05), QRS (Ex vs. Sed : 60.5±2.4 vs 70.8±1.6 ms, p&lt;0.05), QTc (Ex vs. Sed: 213.6±2.8 vs. 237.1±3.4 ms, p&lt;0.05), Tp-Te (Ex vs. Sed: 27.9±2.5 vs.36.5±1.7 ms, p&lt;0.05) intervals associated with significantly enhanced QT interval variability (eg. Ex vs. Sed: QT-STV, 2.5±0.2 vs. 3.6±0.4 ms, p&lt;0.05), reflecting elevated level of repolarization dispersion. Ectopic activity was also enhanced in the exercised dog ventricle. Atropine treatment resulted in moderate heart rate increase in the Ex animals. Chronic endurance exercise elevated the proarrhythmic risk and consequent ventricular fibrillation in dogs subjected to burst electrical stimulation.

Conclusion

We developed a new animal model that shares similarities with the human endurance-trained athlete’s heart. The model represents increased arrhythmia susceptibility, an important clinical paradigm, and explores potential underlying mechanisms, including vagal enhancement, increased repolarization dispersion and enhanced fibrotic changes. Increased arrhythmia susceptibility is supported by the enhanced arrhythmia incidence in the exercised group. Similar changes may be present in young human top athletes, however further investigations are required.

P1711 Exploring the full spectrum of right ventricular exercise contractile reserve among health and disease: a prospective clinical and echocardiography observational multicenter study

Funding Acknowledgements

None

OnBehalf

RIGHT-NET

Background

Exercise Doppler echocardiography (EDE) has been implemented for applications beyond coronary artery disease detection, but its role in assessing subclinical pulmonary vascular disease and right ventricle (RV) impairment is less clear. The RIGHT heart international NETwork (RIGHT-NET) is a prospective clinical and echocardiography observational multicenter study designed to explore the full spectrum of RV function and non-invasive pulmonary circulation hemodynamics during exercise in a large cohort of subjects, from healthy individuals and elite athletes to patients with overt or at risk of developing pulmonary hypertension (PH). Right ventricular (RV) exercise contractile reserve (RVECR) can be assessed through the ratio between tricuspid annular plane systolic excursion (TAPSE) and systolic pulmonary artery pressure (sPAP) and has proved to provide prognostic value in patients with left heart disease (LHD) and pulmonary arterial hypertension (PAH).

Methods

We enrolled 1424 patients (age 55.4 ± 15 years old, 44.4% males): 353 healthy controls, 40 athletes, 369 patients with cardiovascular risk factors (CVRF: arterial hypertension and/or diabetes mellitus), 46 with PAH (confirmed by right heart catheterization), 487 with systemic sclerosis (SSc) without overt PH, and 129 with LHD (including coronary artery disease and heart failure with reduced or preserved ejection fraction).

All enrolled subjects underwent resting and EDE examinations on a semirecumbent cycle ergometer with an incremental workload of 25 Watts every 2 minutes up to the symptom-limited maximal tolerated workload, according to standardised protocols. Key echocardiographic measurements have been acquired at baseline, at 50 Watts, at peak exercise, and after 5-minutes recovery, including but not limited to RV function (TAPSE) and sPAP.

Results

In all six groups the ratio TAPSE/sPAP was significantly different at peak exercise compared to rest values (all p &lt; 0.01). At rest, TAPSE/sPAP values were not significantly different among controls, athletes and CVRF patients, whereas during exercise TAPSE/sPAP values were significantly different, with CVRF showing the lowest values (p &lt; 0.0001 vs controls and athletes). Patients with PAH and LHD had the worst RVECR both at rest and at peak exercise (all p &lt; 0.0001 vs the other groups), while SSc groups reported intermediate values, which were lower than controls (p &lt; 0.0001) and athletes (p &lt; 0.0001), but higher than CVRF subjects (p = 0.003). (Figure)

Conclusions

EDE can non-invasively characterise different dynamic behaviours of the RVECR among healthy subjects, athletes and patients with various pathologic conditions. Whether a thorough EDE assessment of non-invasive hemodynamics, RVECR and coupling may predict later development of manifest PH, clinical deterioration or decreased survival will be further investigated during the ongoing follow-up.

Abstract P1711 Figure

Clinical, functional and prognostic correlates of blunted heart rate reserve during exercise stress echocardiography in hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Background

Blunted heart rate reserve (HRR) during exercise is associated with cardiac autonomic dysfunction and poor outcome.

Purpose

To evaluate the anatomical, functional and prognostic correlates of HRR during exercise stress echocardiography (ESE) in hypertrophic cardiomyopathy (HCM).

Methods

We prospectively recruited a consecutive sample of 121 HCM patients [age 47 ± 13 years, 67 males; NYHA class 1.7 ± 0.7; left ventricular (LV) ejection fraction 71 ± 9 %; LV maximal wall thickness 24 ± 5 mm; 58 (48%) with LV outflow tract obstruction (LVOTO, gradient ≥ 50 mmHg) at rest] who underwent semi-supine bicycle ESE from January 2006 to September 2019. HRR was calculated as the peak/rest heart rate (HR) ratio. All patients were followed-up for a median of 7.5 years.

Results

HR was 68 ± 11 bpm at rest and 105 ± 19 bpm at peak stress. Receiver-operating characteristic analysis was used to determine the best cut-off value of HRR (≤ 1.48, blunted) to predict all-cause death. A blunted HRR was present in 52 patients (43 %, Group 1). Patients with blunted HRR had more frequently hypertension (Group 1= 41/52 vs Group 2= 40/69, 79 vs 58 %, p = 0.019), resting systolic anterior motion of the mitral valve [(SAM) , Group 1= 41/52 vs Group 2= 40/69, 79 vs 58 %, p = 0.019] and rest LVOTO (Group 1= 31/52 vs Group 2= 27/69, 60 vs 39 %, p = 0.029).  Patients in Group 1 had larger left atrial diameter (48.8 ± 6.5 vs 46.5 ± 7.6, p = 0.076), lower LV end-diastolic [(EDD) , 44.8 ± 4.6 vs 46.7 ± 4.6 mm p = 0.02] and LV end-systolic diameter [(ESD), 25.2 ± 5.3 vs 27.6 ± 5.5 mm p = 0.02] at rest. Patients in Group 1 had higher NYHA class (1.9 ± 0.6 vs 1.6 ± 0.7, p = 0.009), resting HR (71.5 ± 11.4 vs 64.6 ± 10.6 bpm p &lt; 0.001), and shorter total exercise time (6.3 ± 3.1 vs 9.1 ± 2.8 min, p &lt; 0.001) compared to patients in Group 2.

During the follow-up, 13 patients died. All-cause death was observed in 10/52 patients of Group 1 and 3/69 patients of Group 2 (19 vs 4 %, p &lt; 0.05). Cox multivariate regression survival analysis revealed that HRR ≤ 1.48 (Hazard ratio 3.7, 95% CI 0.96-14.5, p = 0.048) and left atrial diameter (Hazard ratio 1.15, 95% CI 1.04-1.28, p = 0.003) were independent predictors of all-cause mortality, either on or off beta-blocker therapy.

Conclusion

HRR is a simple non-imaging biomarker of cardiac autonomic function and is frequently abnormal in HCM. The blunted increase in frequency is associated with NYHA functional class, exercise time, rest HR, rest LVOTO, SAM, LV EDD and ESD. HRR independently predicts survival in HCM. The lower the HRR, the worse the outcome.

Abstract Figure.

Pulmonary congestion during exercise stress echocardiography in hypertrophic cardiomyopathy

Background

B-lines detected by lung ultrasound (LUS) indicate pulmonary congestion during exercise stress echo (ESE).

Aim

To assess B-lines during ESE in hypertrophic cardiomyopathy (HCM).

Methods

We enrolled 110 HCM patients (age 52±16 years, 74 males) referred for ESE (treadmill in 39, semi-supine bicycle in 71 patients) in 10 quality-controlled centers from 8 countries (Belgium, Brazil, Bulgaria, Hungary, Italy, Portugal, Serbia, Spain). ESE assessment included: left ventricular outflow tract gradient (LVOTG); mitral regurgitation (MR, score from 0 to 3); E/e'; systolic pulmonary arterial pressure (SPAP, from tricuspid regurgitant jet velocity); end-diastolic volume (EDV); left atrial volume (LAV). B-lines were assessed by LUS with the 4-site simplified scan, each site scored from 0 (normal A-lines) to 10 (coalescing B-lines). The positivity criterion was a B-line score stress ≥2 points.

Results

LUS was feasible in all subjects, with additional scanning and analysis time &lt;1 minute for each stage (rest and peak stress). B-lines were present in 13 patients at rest and in 33 during stress (12 vs 30%, p&lt;0.001). When compared to patients without stress B-lines (Group 2, n=77), patients with B-lines (Group 1) showed higher values of change from rest to stress (Δ) in LVOTG (Group 1= 39±54 vs Group 2= 21±24 mm Hg, p=0.015) and ΔMR grade (Group 1= 0.7±0.8 vs Group 2= 0.1±0.5, p&lt;0.001), more frequent peak stress E/e' ≥15 (Group 1=61% vs Group 2=27%, p=0.007), lower peak EDV (Group 1= 86±35 vs Group 2= 102±33 ml, p=0.039) and higher peak SPAP (Group 1= 60±21 vs Group 2= 39±12 mm Hg, p&lt;0.001): see figure. At multivariable logistic regression analysis, presence of stress B-lines was predicted by ΔMR grade (odds ratio: 3.96, 95% CI 1.46–10.71) and stress E/e' ≥15 (odds ratio: 4.95, 95% CI 1.24–19.70).

Conclusion

B-lines are found in about 1 of 10 HCM patients at rest and in 1 of 3 during ESE. Acute backward heart failure during exercise can recognize multiple mechanisms in HCM, and ESE can help to capture this heterogeneity.

Funding Acknowledgement

Type of funding sources: None. Functional correlates of stress B-lines

Prognostic role of coronary flow velocity reserve in hypertrophic cardiomyopathy

Background

A reduction in coronary flow velocity reserve (CFVR) related to coronary microvascular dysfunction is a major mechanism for ischemia in hypertrophic cardiomyopathy (HCM).

Hypothesis

To assess the functional correlates and prognostic value of CFVR during stress echocardiography (SE) in HCM.

Methods

We enrolled 201 HCM patients (age 51±14 years, 105 male, 52%; maximal wall thickness: 18±3 mm) studied with CFVR during exercise (n=33, 16.4%), dipyridamole (n=89, 44.3%) or adenosine (n=79, 39.3%) SE in 6 certified centers. CFVR was assessed using pulsed wave Doppler sampling in left anterior descending coronary artery. All patients completed the clinical follow-up.

Results

During SE mean value of CFVR was 2.11±0.46. No patients showed regional wall motion abnormalities during stress. LV outflow tract obstruction (LVOTO) was present in 34 (16.9%) patients at rest and in 47 (23.4%) at peak stress. CFVR was inversely related to age (r=−0.229, p=0.001) and maximal wall thickness (r=−0.197, p=0.031). During a median follow-up of 26 months (IQ range: 12–48 months), 75 events in 63 patients occurred: 10 deaths, 33 new hospital admission for acute heart failure, 8 sustained ventricular tachycardias and 24 atrial fibrillations. Patients in the lowest tertile (≤1.88) showed the worse prognosis with higher incidence of follow-up events compared to median tertile (1.89–2.29) and highest tertile (≥2.30) (see figure). At multivariable analysis, NYHA functional class (HR: 2.234, 95% CI: 1.398–3.517, p=0.001), presence of LVOTO at rest (HR: 2.958, 95% CI: 1.074–3.570, p=0.028) and lowest tertile of CFVR (HR: 2.144, 95% CI: 1.126–4.081, p=0.011) were the independent predictors of follow-up events.

Conclusions

In HCM patients, reduction in CFVR is associated to a clearly worse outcome. The spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale.

Figure 1

Funding Acknowledgement

Type of funding source: None