Ventricular Reserve Research Articles

Quantitative evaluation of myocardial perfusion in coronary heart disease by myocardial contrast and dobutamine stress echocardiography

AbstractObjectiveWe aimed to investigate how combining myocardial contrast echocardiography (MCE) with dobutamine stress echocardiography (DSE) could help evaluate myocardial perfusion in coronary heart disease patients and understand changes in microcirculation across different levels of coronary artery blockage.MethodsWe conducted MCE and DSE tests on 53 coronary heart disease patients, categorizing ischemic myocardium into four groups: A (<50%), B (50%–69%), C (70%–89%), and D (≥90%). Dynamic myocardial perfusion images were captured during rest and peak dobutamine stress from various angles, analyzing parameters like plateau value A, slope β, and the product A × β, reflecting different aspects of myocardial blood flow.ResultsParametric values of myocardial perfusion (PVMPs) were significantly lower in group D at rest compared with other groups (p < 0.001). PVMPs increased notably at peak dobutamine stress in groups A, B, and C (p < 0.001). Groups A and B had higher PVMPs than groups C and D, with group D significantly lower (p < 0.001). β reserve values decreased gradually from group A to D, with significantly lower values of A and A × β in groups C and D compared with A and B (p < 0.001). Sensitivity and specificity for predicting >70% coronary artery blockage was 80%, 66%, and 74%, 80%, respectively, using specific thresholds.ConclusionCombining MCE with DSE is highly sensitive and accurate in diagnosing obstructive coronary artery blockages. It also helps assess myocardial microcirculation perfusion and left ventricular reserve function, which decline with increasing severity of coronary artery blockage.

How preserved is right ventricular reserve in hypoxia?

How preserved is right ventricular reserve in hypoxia?

Association between aortic valve opening during exercise and right ventricular reserve in patients with left ventricular assist device

Abstract Background Aortic valve (AV) opening in patients after left ventricular (LV) assist device (LVAD) implantation is important to prevent adverse events. We hypothesised that right ventricular (RV) reserve function would play a crucial role to overcome pulmonary vascular resistance to ensure LV filling and AV opening in LVAD patients. However, detailed analysis between RV haemodynamic exercise response and AV opening with recent LVAD patients remains relatively unknown. Purpose The aim of this study was to explore the haemodynamic parameters observed during rest and maximal exercise and investigate the association of AV opening with RV reserve function and adverse events in patients with LVAD. Methods We prospectively examined 22 consecutive LVAD patients who were admitted to our university hospital between June 2020 and December 2022 after excluding those who were unable to perform exercise (n = 8). All patients underwent invasive exercise right heart catheterisation with simultaneous echocardiography in the supine position. AV status was assessed at rest and during exercise. RV stroke work index (RVSWI) was calculated as 0.0136 × stroke volume index × (mean pulmonary artery pressure – right atrial pressure) at rest and during exercise. RVSWI change from rest to peak exercise (ΔRVSWI) were calculated to evaluate RV reserve function. The patients were divided into three groups according to AV opening both rest and exercise (n = 6), AV opening only during exercise (n = 7), and AV closed both rest and exercise (n = 9). Results Patients were predominantly male (77%) and the median age was 51 (interquartile range [IQR] 39-63) years. There were no significant differences in age, sex, primary aetiology of heart failure, type of LVAD devices or echocardiographic parameters and RVSWI at rest among the groups. Patients with AV opening both rest and exercise, and only during exercise had significantly higher ΔRVSWI than those with AV closed both rest and exercise (Figure A). During a median follow-up period of 433 (IQR 228-558) days, adverse events occurred in six patients (27%), including one death, one hospitalisation for major bleeding, and four hospitalisations for right heart failure. Kaplan–Meier analysis revealed that the adverse events more frequently occurred in patients with AV closed both rest and exercise compared to those with AV opening (p = 0.014) (Figure B). Conclusions In patients with LVAD, AV opening at rest or during exercise was associated with preserved RV reserve function and less adverse events. These findings suggest that the observation of the AV opening during exercise would be useful for early identification of high-risk patients with LVAD. Further studies are needed to confirm our findings.

CARDIAC FUNCTION EVALUATION THROUGH ECHOCARDIOGRAM IN RECENTLY DIAGNOSED TYPE 2 DIABETES MELLITUS PATIENTS

Introduction: Diabetes mellitus being a modern day disease has occupied a significant place in burdening the health care system.The abnormalities in the glucose metabolism have a significant impact on the cardiovascular system and usually is an unfavourable outcome.In this study, persons with type II diabetes mellitus were assessed for developing cardiac dysfunction (Left ventricular) and its prevalence by comparing with asymptomatic control group. Age and gender were matched among these two groups. Objectives: The primary objective was toevaluate the left ventricular reserve (systolic & diastolic) in recently diagnosed type 2 diabetes mellitus patients. The secondary objective is to assess the risk factorscontributing in the development of heart failure among diabetic patients. Methods: This case control study was explored among the recently diagnosed diabetes mellitus (Type 2) patients who were visitingdiabetic OPD. Approval for the conductance of the study was obtained from the Institutes scientific committee and the Institutes ethics committee. The study period was from January, 2022 to March, 2023. In study group recently diagnosed type 2 diabetes mellitus patients were considered as the participants based on the revised criteria for diagnosing diabetes mellitus taken from American Diabetes Association. LV systolic functionwas assessed from the following calculated with the M- mode echocardiogram. Results: Incidence of diastolic dysfunction in study population was 28%, whereas in control population was 10%. Diastolic dysfunction based on the distribution amongst study population is 50% between 40-50 years. Gender distribution of derangement in diastolic function amongst study population were 31.25% amongstfemales, 22% amongst males and in controls was 10% amongst females, 10% amongst males. Conclusion: The incidence of abnormal diastolic function was notablyincreasing in recently diagnosed diabetes mellitus (type 2) patients as paralleled to participants with normal glucose metabolism. Prevalence of diastolic dysfunction amongst newly diagnosed male and female diabetics is in the ratio of 2:1. Risk factors like advanced age, abnormal BMI, PPBS, raised HbA1c, elevated cholesterol and triglyceride values are significantly associated with diastolic dysfunction.

Role of reduced left atrial mechanical function reserve in exercise intolerance progression in hypertensive heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background The identification of mechanisms in hypertensive heart disease (HHD) that favor the development of symptomatic heart failure (HF) is essential. Little is known about the role of left atrial (LA) mechanical response to exertion in this context. Objectives We sought to investigate the association of LA strain parameters response to exercise with functional capacity and symptomatic HF in a representative group with HHD. Methods Echocardiography (including LA strain and strain-derived LA stiffness index assessment) was performed at rest and immediately post exercise test in 61 patients with stage A, 67 patients with stage B and 73 patients with stage C HF. Results There was a progressive worsening of exercise capacity from stage A through stage B to stage C, which was accompanied by a gradual impairment of changes from rest to exercise in LA reservoir and contractile strain, whereas LA stiffness reserve remained unchanged until the HF stage C (Table). In multivariable analysis including LA and left ventricular reserve and clinical variables, changes from rest to exercise in LA reservoir strain and mitral annular e’ (both beta 0.16, SE 0.07, p = 0.02) were the only cardiac function parameters independently correlating with exercise capacity. However, LA stiffness reserve and E/e’ were the strongest associations of symptomatic HF stage C (Akaike information criterion 111.6 and 101.1, respectively). Conclusions LA reservoir strain and LA stiffness exercise reserves are among the mediators of reduced functional capacity in HHD, however the trajectories of changes of these parameters are not parallel. While LA strain reserve progressively deteriorates across HF stages, a marked impairment in LA stiffness reserve can only be seen in patients with HF symptoms. This suggests a potential role for these parameters in stratifying the risk of progression to overt HF in HHD.

Impact of right ventricular reserve on exercise capacity and quality of life in patients with left ventricular assist device.

Although measuring right ventricular (RV) function during exercise is more informative than assessing it at rest, the relationship between RV reserve function, exercise capacity, and health-related quality of life (HRQoL) in patients with left ventricular assist devices (LVAD) remains unresolved. We aimed to investigate whether RV reserve assessed by the change in RV stroke work index (RVSWI) during exercise is correlated with exercise capacity and HRQoL in patients with LVAD. We prospectively assessed 24 consecutive patients with LVAD who underwent invasive right heart catheterization in the supine position. Exercise capacity and HRQoL were assessed using the 6-min walk distance (6 MWD) and peak oxygen consumption (V̇o2) in cardiopulmonary exercise testing, and the EuroQol visual analog scale (EQ-VAS), respectively. The patients were divided into two groups according to the median ΔRVSWI (change from rest to peak exercise). Patients with lower ΔRVSWI had significantly lower changes in cardiac index and absolute value of RV dP/dt than those with higher ΔRVSWI. The ΔRVSWI was positively correlated with 6 MWD (r = 0.59, P = 0.003) and peak V̇o2 (r = 0.56, P = 0.006). In addition, ΔRVSWI was positively correlated with the EQ-VAS (r = 0.44, P = 0.030). In contrast, there was no significant correlation between RVSWI at rest and 6 MWD (r = -0.34, P = 0.88), peak V̇o2 (r = 0.074, P = 0.74), or EQ-VAS (r = 0.127, P = 0.56). Our findings suggest that the assessment of RV reserve function is useful for risk stratification in patients with LVAD.NEW & NOTEWORTHY The change in right ventricular stroke work index (RVSWI) during exercise, not RVSWI at rest, was associated with exercise capacity and HRQoL. Our findings suggest that the assessment of change in RVSWI during exercise as a surrogate of RV reserve function may aid in risk stratification of patients with LVAD.

S-45-4: THE EFFECTS OF HANDGRIP STRESS TEST ON HEMODYNAMIC PARAMETERS IN PATIENTS WITH HYPERTENSION AND DIASTOLIC HEART FAILURE

Aim: The effectiveness of isometric handgrip exercise on changes of cardiovascular hemodynamic parameters in patients with diastolic heart failure is unknown. We assess the effect of several hemodynamic parameters and it changes during handgrip maneuvers in patients with arterial hypertension and diastolic heart failure during different stages of chemotherapy. Methods: The study population included 245 patients females /120 pts with HFpEF and 100 pts with HFmrEF and 25 pts with HFnEF / mean age of 45 years/. The effects of handgrip maneuver on hemodynamic parameters were studied by speckle tracking echocardiography. Following maximal squeeze until 100%, during the next 3 minutes patients were instructed to apply pressure at 50 %. The global longitudinal strain were extracted by 3, 4 and 2 CV images 70 fr/s and MAP and HR were performed at basal level, 1st, 2nd and 3rd minutes during handgrip stress test. Results: Heart rate (HR) and mean arterial pressures (MAP) increased significantly after handgrip maneuver (from 95 beats/min to 101 beats/min; from 109 mm Hg to 118 mm Hg, p < 0.05 respectively). Pulmonary capillary wedge pressure (PCWP), pulmonary artery systolic (s) and diastolic (d) pressures (PAP), cardiac index (CI), left ventricular ejection fraction (LVEF), did not change after handgrip maneuvers (p > 0.05). On the other hand, PAPs and PAPd, MAP and HR (p < 0.05) decreased significantly during handgrip maneuvers in group with HFmrEF. In same group were found significantly decreases of GLVLS at 2nd and 3rd minutes during stress test comparable with other 2 groups / p < 0.01/ Conclusion: Cardiovascular response to handgrip maneuver may be a marker of failure to respond to compensatory mechanisms. Patients with good LV reserve had a rise in stroke /work with little or no change in LVEDP. Patients with poor reserve had a fall in stroke/ work together with a substantial rise in LVEDP. It is concluded that the stress imposed by sustained handgrip provides a simple test for the evaluation of left ventricular reserve in patients, who will develop cardiotoxicity during chemotherapy treatment.

Impact of right ventricular reserve on exercise capacity and quality of life in patients with left ventricular assist device

Abstract Background Right heart failure following left ventricular assist device (LVAD) implantation is a major complication which significantly impairs functional capacity and quality of life (QoL). Right ventricular (RV) reserve function may limit exercise capacity and QoL in LVAD patients; however, most patients show normal RV haemodynamics at rest. Purpose The aim of this study was to investigate whether RV reserve assessed by the changes of RV function during exercise is correlated with exercise capacity and QoL in patients with LVAD. Methods We prospectively examined 20 consecutive LVAD patients who were admitted to our university hospital between June 2020 and November 2021 after excluding those who were unable to perform exercise (n=8). All patients underwent invasive exercise right heart catheterisation with simultaneous echocardiography in the supine position. RV stroke work index (RVSWI) was calculated as 0.0136 × stroke volume index × (mean pulmonary artery pressure [mPAP] − right atrial pressure [RAP]) at rest and during exercise. Exercise capacity and QoL were assessed by 6-minute walk distance (6MWD) and peak oxygen consumption (VO2) in cardiopulmonary exercise testing, and the EuroQol visual analogue scale (EQ-VAS), respectively. The patients were divided into two groups according to the median ΔRVSWI (RVSWI change from rest to peak exercise) of 1.45 (interquartile range [IQR] −0.31 to 8.25) g/m2. Results Patients were predominantly male (75%) and the median age was 47 (IQR 38–60) years. Patients with lower ΔRVSWI had significantly higher change on RAP (P=0.019), but significantly lower change on mPAP (P<0.001) compared to those with higher ΔRVSWI. There were no significant differences in age, gender, primary aetiology of heart failure, type of LVAD devices, or echocardiographic parameters including tricuspid annular plane systolic excursion, and RVSWI at rest between the groups. ΔRVSWI during exercise were positively correlated with 6MWD (R=0.69, P<0.01) and peak VO2 (R=0.66, P<0.01) (Figure A). In addition, ΔRVSWI during exercise were positively correlated with the EQ-VAS (R=0.48, P=0.031). On the other hand, there was no significant correlation between RVSWI at rest and 6MWD (R=−0.11, P=0.63) and peak VO2 (R=0.13, P=0.95), and the EQ-VAS (R=0.11, P=0.61). During a median follow-up period of 312 (IQR 176–369) days, adverse events occurred in 3 patients (15%), including 1 death and 2 hospitalisations for major bleeding and right heart failure. Kaplan-Meier analysis revealed that the adverse events more frequently occurred in patients with lower ΔRVSWI compared to those with higher ΔRVSWI (Figure B). Conclusions ΔRVSWI was positively correlated with 6MWD, peak VO2 and EQ-VAS irrespective of RV function at rest. Our findings suggest that the assessment of RV reserve function using ΔRVSWI would be useful for risk stratification in patients with LVAD. Funding Acknowledgement Type of funding sources: None.

PROGNOSTIC VALUE OF NONINVASIVE EXERCISE CARDIAC INDEX MEASUREMENTS IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION

SESSION TITLE: PAH Abstract PostersSESSION TYPE: Original Investigation PostersPRESENTED ON: 10/18/2022 01:30 pm - 02:30 pmPURPOSE: Background: Patients with pulmonary arterial hypertension (PAH) have a reduced ability to increase cardiac index (CI) in response to exercise due to impaired right ventricular reserve. Whether this impaired CI augmentation correlates with quality of life (QoL), or the risk of clinical deterioration in PAH is unknown. Impedance cardiography (ICG) can accurately and noninvasively measure CI in PAH.Research Question:In patients with PAH, does the change in CI (ΔCI) with exercise, assessed with ICG, predict clinical worsening at 1 year?METHODS: Study Design & Methods: Patients with WHO Group 1 PAH were recruited and performed a 6MWT according to ATS standards. A Noninvasive Cardiac System (NICaS, NIMedical) ICG was used to measure the cardiac index at rest and immediately post-test. The primary analysis will be the association between ΔCI and clinical worsening at 1-year. This interim analysis describes the association between ΔCI and 6MWD, QoL (using emPHasis-10 score), and REVEAL 2.0 risk score using Pearson correlation.RESULTS: 19 patients completed the 6MWT (mean±SD: age 60±12 years, disease duration 37±30 months, number of PAH-targeted therapies 1.9±0.8). Mean resting CI was 2.72±0.5 L/min/m2. Following the 6MWT, the mean increase in CI was 1.36±1.09 L/min/m2 (range -0.02-3.03 L/min/m2), due to increases in heart rate (13.2±11.4bpm, range -1 to 41bpm) and stroke volume (9.5±10.1ml, range -2-22.7ml). ΔCI was not associated with walk distance (r=0.26, p=0.14), REVEAL 2.0 risk score (r=0.12, p=0.33), or emPHasis-10 (r=0.24, p=0.16). CI at end-exercise was associated with walk distance (r=0.41, p=0.039). A greater heart rate augmentation was associated with poorer quality of life (r=0.41,p=0.039) and higher-risk REVEAL score (r=0.44,p=0.029), although this was not explained by a compensatory increase for impaired stroke volume augmentation.CONCLUSIONS: Interpretation: In PAH, the change in cardiac index with exercise was not associated with 6MWD, NT-pro-BNP, QoL, or clinical risk score. Greater tachycardia with exercise was associated with worse QoL and clinical risk score. A 1-year follow-up is planned to determine whether ΔCI has any potential role in predicting PAH progression.CLINICAL IMPLICATIONS: TBDDISCLOSURES: No relevant relationships by Lauren BathNo relevant relationships by David ChristiansenNo relevant relationships by Ashish Shah SESSION TITLE: PAH Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/18/2022 01:30 pm - 02:30 pm PURPOSE: Background: Patients with pulmonary arterial hypertension (PAH) have a reduced ability to increase cardiac index (CI) in response to exercise due to impaired right ventricular reserve. Whether this impaired CI augmentation correlates with quality of life (QoL), or the risk of clinical deterioration in PAH is unknown. Impedance cardiography (ICG) can accurately and noninvasively measure CI in PAH. Research Question:In patients with PAH, does the change in CI (ΔCI) with exercise, assessed with ICG, predict clinical worsening at 1 year? METHODS: Study Design & Methods: Patients with WHO Group 1 PAH were recruited and performed a 6MWT according to ATS standards. A Noninvasive Cardiac System (NICaS, NIMedical) ICG was used to measure the cardiac index at rest and immediately post-test. The primary analysis will be the association between ΔCI and clinical worsening at 1-year. This interim analysis describes the association between ΔCI and 6MWD, QoL (using emPHasis-10 score), and REVEAL 2.0 risk score using Pearson correlation. RESULTS: 19 patients completed the 6MWT (mean±SD: age 60±12 years, disease duration 37±30 months, number of PAH-targeted therapies 1.9±0.8). Mean resting CI was 2.72±0.5 L/min/m2. Following the 6MWT, the mean increase in CI was 1.36±1.09 L/min/m2 (range -0.02-3.03 L/min/m2), due to increases in heart rate (13.2±11.4bpm, range -1 to 41bpm) and stroke volume (9.5±10.1ml, range -2-22.7ml). ΔCI was not associated with walk distance (r=0.26, p=0.14), REVEAL 2.0 risk score (r=0.12, p=0.33), or emPHasis-10 (r=0.24, p=0.16). CI at end-exercise was associated with walk distance (r=0.41, p=0.039). A greater heart rate augmentation was associated with poorer quality of life (r=0.41,p=0.039) and higher-risk REVEAL score (r=0.44,p=0.029), although this was not explained by a compensatory increase for impaired stroke volume augmentation. CONCLUSIONS: Interpretation: In PAH, the change in cardiac index with exercise was not associated with 6MWD, NT-pro-BNP, QoL, or clinical risk score. Greater tachycardia with exercise was associated with worse QoL and clinical risk score. A 1-year follow-up is planned to determine whether ΔCI has any potential role in predicting PAH progression. CLINICAL IMPLICATIONS: TBD DISCLOSURES: No relevant relationships by Lauren Bath No relevant relationships by David Christiansen No relevant relationships by Ashish Shah

Impella CP to Impella 5.5 Uninterrupted Upgrade Using a Double Device Technique.

For the first time, we present a novel technique that enables the exchange of the Impella CP (Abiomed Inc., Danvers, Massachusetts, USA) to the Impella 5.5 (Abiomed Inc.) with no interruption of mechanical support in patients with minimal left ventricular reserve. Specifically, the aortic valve is crossed with the Impella 5.5 whereas the Impella CP is still functioning within the left ventricle. The Impella 5.5 is then initiated, and the Impella CP is weaned. Finally, the Impella CP is pulled out into the descending aorta. This exchange provides continuous support with no hemodynamic disarrangement.

Right Ventricle Pressure-Volume Analysis During LVAD Explant Evaluation

<h3>Introduction</h3> Careful patient selection for left ventricular assist device (LVAD) explant after myocardial recovery involves echocardiographic and invasive hemodynamic assessment at safest minimal speed at rest and with exercise, indirect measures of cardiac function. Pressure-volume loop (PVL) analysis may supplement this process by directly assessing ventricular function. <h3>Case Report</h3> A 41 year old male underwent HeartMate3 LVAD placement 2.5 years prior for dilated cardiomyopathy. Post-LVAD, significant reverse remodeling on maximally tolerated guideline directed medical therapy (GDMT) was seen: left ventricular end diastolic diameter (LVEDD) was 4.2 cm (6.1cm pre-LVAD); ejection fraction (EF) was 40-45%. He was referred for exercise right heart catheterization for possible explant after developing incessant low flow LVAD alarms despite speed and medication adjustments. As part of an IRB-approved research protocol, PVLs of the resting right ventricle (RV) were obtained at multiple LVAD speeds. Clinical data were equivocal: chambers did not dilate, but rest cardiac index (CI) fell from 2.3 to 1.9 L/min/m² at a minimal speed of 4000 rpm. Filling pressures rose as speed decreased and increased to pathologic levels during exercise, which was reduced versus age- and sex-matched controls. Explant was not pursued given results and transplant was more aggressively pursued. Subsequent analysis of RV PVLs supported this decision (<b>Figure 1)</b>. RV-pulmonary artery (PA) relationship was preserved at initial speed of 5100 rpm. With speed decrease, summed afterload rose as a function of increased filling pressures, but Ees failed to augment. As a result, ventriculo-vascular coupling was lost. RV volumes increased as well, detected via PVL only and not by echo. Based on these results, poor RV contractile reserve may have contributed to predicted failure to thrive post LVAD explant. <h3>Summary</h3> PVL analysis may provide additional information to help assess ventricular reserve in LVAD patients being considered for explantation.

Association between Right Ventricular Function and Exercise Capacity in Patients with Chronic Heart Failure.

Background: The association between right ventricular function and exercise capacity in patients with chronic heart failure remains uncertain. Several studies very recently mentioned the association between right ventricular reserve and exercise capacity, whereas the implication of tricuspid annular plane systolic excursion (TAPSE) remains uninvestigated. We aimed to assess the impact of TAPSE on exercise capacity in cardiac rehabilitation candidates. Methods: Data from patients with chronic heart failure who received cardiopulmonary exercise tests and transthoracic echocardiography prior to cardiac rehabilitation were retrospectively collected, and their association was investigated. Results: A total of 169 patients with chronic heart failure (70.3 ± 11.7 years old, 74.6% men) were included. Tertiled tricuspid annular plane systolic excursion significantly stratified anaerobic threshold (10.2 ± 2.2, 11.4 ± 2.2, and 12.2 ± 2.8 mm; p < 0.01) and peak oxygen consumption (15.9 ± 4.5, 18.3 ± 5.3, and 19.8 ± 5.6 mm; p < 0.01). In the multivariate logistic regression analyses, TAPSE was an independent factor associated with anaerobic threshold and peak oxygen consumption (p < 0.05 for both). Conclusions: Right ventricular impairment was associated with reduced exercise capacity in patients with chronic heart failure. Such knowledge would be useful to estimate patients’ exercise capacity and prescribe cardiac rehabilitation. Its longitudinal association and clinical implication need further studies.

Abstract 13419: Novel Methods to Quantify Limitation of Right Ventricular Exercise Reserve in Pulmonary Hypertension: Afterload vs Ventricular Interdependency

Introduction: In this study, we report novel methods to investigate impact of pulmonary arterial (PA) afterload with impedance and ventricular interdependency with myocardial strain on right ventricular (RV) reserve with exercise and RV:PA coupling. Hypothesis: In pre-capillary pulmonary hypertension (PH), RV is conditioned to a higher contractility (end-systolic elastance: Ees) due to increased impedance and RV reserve is independent of left ventricle. However, in isolated post-capillary PH (Ipc-PH), RV is not conditioned due to lower impedance, yet contractility reserve is poor due to lower interventricular septal strain. Methods: In 4 subjects (Table 1), we performed invasive cardiopulmonary exercise tests with simultaneous echocardiogram for impedance quantification with spectral analysis, followed by real-time RV pressure volume loops (Figure 1A: data recorded at rest and every 25 watts till peak-exercise). Cardiac MRI was performed within 24-hours to assess myocardial function, strain, and 4D flow at rest and exercise in the bore. Results: The augmentation of RV contractility (Ees) with exercise is poor in Ipc-PH, despite an afterload (Ea) similar to the normal subject. The left ventricular septal strain is reduced in Ipc-PH which may indicate enhanced interventricular dependency. Due to increased afterload in pre-capillary PH, RV is conditioned to higher contractility (Ees), and RV reserve is possibly independent of the left ventricle. Conclusion: Our novel methods provide an opportunity to investigate mechanisms of poor RV reserve with exercise in different phenotypes of PH. We will further validate these preliminary findings in our ongoing studies.

Myocardial adaptation and exercise performance in patients with pulmonary arterial hypertension assessed with patient-specific computer simulations.

Myocardial function and exercise reserve are important determinants of outcome in pulmonary arterial hypertension (PAH) but are incompletely understood. For this study, we performed subject-specific computer simulations, based on invasive measurements and cardiac magnetic resonance imaging (CMR), to investigate whole circulation properties in PAH at rest and exercise and determinants of exercise reserve. CMR and right heart catheterization were performed in nine patients with idiopathic PAH, and CMR in 10 healthy controls. CMR during exercise was performed in seven patients with PAH. A full-circulation computer model was developed, and model parameters were optimized at the individual level. Patient-specific simulations were used to analyze the effect of right ventricular (RV) inotropic reserve on exercise performance. Simulations achieved a high consistency with observed data. RV contractile force was increased in patients with PAH (127.1 ± 28.7 kPa vs. 70.5 ± 14.5 kPa, P < 0.001), whereas left ventricular contractile force was reduced (107.5 ± 17.5 kPa vs. 133.9 ± 10.3 kPa, P = 0.002). During exercise, RV contractile force increased by 1.56 ± 0.17, P = 0.001. In silico experiments confirmed RV inotropic reserve as the important limiting factor for cardiac output. Subject-specific computer simulation of myocardial mechanics in PAH is feasible and can be used to evaluate myocardial performance. With this method, we demonstrate marked functional myocardial adaptation to PAH in the resting state, primarily composed of increased contractile force development by RV myofibers, and we show the negative impact of reduced RV inotropic reserve on cardiac output during exercise.NEW & NOTEWORTHY Computer simulations of the myocardial mechanics and hemodynamics of rest and exercise were performed in nine patients with pulmonary arterial hypertension and 10 control subjects, with the use of data from invasive catheterization and from cardiac magnetic resonance. This approach allowed a detailed analysis of myocardial adaptation to pulmonary arterial hypertension and showed how reduction in right ventricular inotropic reserve is the important limiting factor for an increase in cardiac output during exercise.

Assessment of right ventricular reserve utilizing exercise provocation in systemic sclerosis.

Right ventricular (RV) capacity to adapt to increased afterload is the main determinant of outcome in pulmonary hypertension, a common morbidity seen in systemic sclerosis (SSc). We hypothesized that supine bicycle echocardiography (SBE), coupled with RV longitudinal systolic strain (RVLSS), improves detection of limitations in RV reserve in SSc. 56 SSc patients were prospectively studied during SBE with RV functional parameters compared at rest and peak stress. We further dichotomized patients based on resting RV systolic pressure (RVSP) to determine the effects of load on contractile response. Our pooled cohort analysis revealed reduced global RVLSS at rest (-16.2 ± 3.9%) with normal basal contractility (-25.6 ± 7.7%) and relative hypokinesis of the midventricular (-14.1 ± 6.0%) and apical (-8.9 ± 5.1%) segments. With exercise, global RVLSS increased significantly (p = 0.0005), however despite normal basal contractility at rest, there was no further augmentation with exercise. Mid and apical RVLSS increased with exercise suggestive of RV contractile reserve. In patients with resting RVSP < 35mmHg, global and segmental RVLSS increased with exercise. In patients with resting RVSP ≥ 35mmHg, global and segmental RVLSS did not increase with exercise and there was evidence of exertional RV dilation. Exercise provocation in conjunction with RVLSS identified differential regional contractile response to exercise in SSc patients. We further demonstrate the effect of increased loading conditions on RV contractile response exercise. These findings suggest subclinical impairments in RV reserve in SSc that may be missed by resting noninvasive 2DE-based assessments alone.

Right Heart Size and Right Ventricular Reserve in Pulmonary Hypertension: Impact on Management and Prognosis.

Various parameters reflecting right heart size, right ventricular function and capacitance have been shown to be prognostically important in patients with pulmonary hypertension (PH). In the advanced disease, patients suffer from right heart failure, which is a main reason for an impaired prognosis. Right heart size has shown to be associated with right ventricular function and reserve and is correlated with prognosis in patients with PH. Right ventricular reserve, defined as the ability of the ventricle to adjust to exercise or pharmacologic stress, is expressed by various parameters, which may be determined invasively by right heart catheterization or by stress-Doppler-echocardiography as a noninvasive approach. As the term “right ventricular contractile reserve” may be misleading, “right ventricular output reserve” seems desirable as a preferred term of increase in cardiac output during exercise. Both right heart size and right ventricular reserve have been shown to be of prognostic importance and may therefore be useful for risk assessment in patients with pulmonary hypertension. In this article we aim to display different aspects of right heart size and right ventricular reserve and their prognostic role in PH.

Abstract 13566: Clinical Utility of Noninvasive Assessment of Flow-pressure Relationship in Scleroderma

Introduction: Cardiac involvement in Systemic sclerosis (SSc), especially left ventricular diastolic dysfunction (DD), is high prevalence and associated with high mortality. Thus, the early detection of left ventricular DD might be important to manage SSc. Recent study has shown that exercise stress test may evaluate an early stage of heart failure in patients with normal resting echocardiogram. Hypothesis: We hypothesized that SSc patients with normal resting hemodynamics may present early phase of left ventricular DD by exercise echocardiogram, leading to the model of predicting long-term outcomes. Methods: Between January 2014 and December 2018, we prospectively enrolled 140 SSc patients who underwent 6-minute walk (6MW) stress echocardiographic studies with normal range of estimated mean pulmonary arterial pressure (mPAP) (&lt;25mmHg) and mean pulmonary artery wedge pressure (mPAWP) (&lt;15mmHg) at rest. We used ΔmPAP/Δcardiac output (CO) to assess pulmonary vascular reserve and ΔmPAWP/ΔCO to assess left ventricular (LV) reserve between resting and post-6MW point. Results: During a median period of 3.6 years, 25 patients (18%) reached the composite outcome. Both ΔmPAP/ΔCO and ΔmPAWP/ΔCO in patients with events were significantly higher than in ones without events (8.9±3.8mmHg/l/min vs. 3.0±1.7mmHg/l/min; p=0.002, and 2.2±0.9mmHg/l/min vs. 0.9±0.5mmHg/l/min; p&lt;0.001, respectively). In addition, ΔmPAWP/ΔCO is strongly associated with events (p=0.04) in patients with normal ΔmPAP/ΔCO (≤median value), although ΔmPAWP/ΔCO had weak impact in patients with abnormal ΔmPAP/ΔCO (&gt;median value) (p=0.23). Conclusions: Exercise echocardiography revealed impaired LV functional reserve in SSc patients with normal resting hemodynamics. Furthermore, in the group of normal pulmonary vascular function, the patients with impaired LV functional reserve had significantly shorter event-free survival than the ones with non-impaired LV function. Thus, the evaluation of early left ventricular DD with 6MW may detect high-risk group in SSc patients.

Right ventricular longitudinal strain with CMR can more accurately estimate right ventricular functional reserve in rats with pulmonary arterial hypertension

Abstract Background Right ventricular (RV) function is an important prognostic factor in patients with pulmonary arterial hypertension (PAH). Recently, CMR has become an attractive modality for follow up and providing prognosis in the patients, and strain has been used as a newer parameter to assess contractile properties of ventricle. It has not yet been established, however, whether RV strain with CMR can estimate RV functional reserve in the patients with PAH. Purpose We focused on CMR imaging of RV, investigating whether RV longitudinal strain can estimate RV functional reserve using a rat model with PAH. Method Rats were given a subcutaneous injection of 60 mg/kg monocrotaline (MCT-rats) or solvent (Ctr-rats). Four weeks after the injection, 25% of MCT-rats died due to RV failure. In the survivors of MCT- (n=19) and Ctr-rats (n=5), retrospective ECG-gated cine MR (16 phases/beat) was imaged with a 7T scanner. Subsequently, we measured RV pressure (RVP) via right internal jugular vein and dissected trabeculae (length = 1.45±0.07 mm, width = 334±27 μm, thickness = 114±6 μm) from RVs. We calculated weight ratio of RV free wall to left ventricle (LV) by RV/(LV+septum). Trabeculae were electrically stimulated with 2-s stimulus intervals, and force was measured using a silicon strain gauge (0.7 mM extracellular Ca2+, 24°C). To determine contractile properties of RV muscle, dF/dt was calculated. Using CMR imaging, we measured RV ejection fraction (RVEF) and RV longitudinal strain (RVLS). To modulate RVP, we intravenously injected 5 nmol endothelin-1 (ET-1) and again measured RVEF and RVLS. Results MCT-rats showed higher systolic RVP (62.5±16.6 vs. 25.9±1.86 mmHg, p&amp;lt;0.01) and higher weight ratio of RV (0.60±0.03 vs. 0.28±0.02, p&amp;lt;0.05). In CMR imaging, MCT-rats showed lower RVEF (36.1±11.2 vs. 64.8±8.4%, p&amp;lt;0.001) and lower RVLS (−18±9 vs. −30±1%, p&amp;lt;0.05). In trabeculae from RVs, MCT-rats showed lower developed force and lower dF/dt (p&amp;lt;0.01). Correlation between RVLS and dF/dt was higher (n=20, r=0.53, p&amp;lt;0.05) than that between RVEF and dF/dt (r=0.24). In addition, RVLS and dF/dt had already been decreased in 5 MCT-rats with relatively preserved RVEF (&amp;gt;50%), suggesting that RVLS decreases earlier than RVEF in MCT-rats. Ten minutes after the injection of ET-1, RVP was increased from 49.4±7.9 to 57.9±6.4 mmHg in MCT-rats (n=6). In MCT-rats with preserved RVEF and decreased RVLS, the increase in RVP chiefly decreased RVEF while it did not change RVLS and RVEF in Ctr-rats, meaning that RV functional reserve had been decreased in MCT-rats. In trabeculae, developed force and dF/dt were increased after the addition of 0.1 μM ET-1 in MCT- (n=11, p&amp;lt;0.01) and Ctr-rats (n=4, p&amp;lt;0.01). Conclusion These results suggest that in rats with PAH, RVLS obtained from CMR can estimate RV functional reserve earlier and more accurately than RVEF. Therefore, RV strain with CMR may become an important parameter to assess RV functional reserve in patients with PAH. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Young Scientists

Right ventricular reserve post mitral valve repair is associated with heart failure hospitalization.

Right ventricular impairment is a predictor of cardiovascular outcomes in patients with degenerative mitral regurgitation. However, the time course of right ventricular functional changes post-surgical mitral valve repair remains largely unknown. Herein, using right ventricular-focused echocardiography, we aimed to investigate right ventricular reserve and its impact on hospitalization for heart failure after mitral valve repair. In this prospective study, we enrolled 108 patients scheduled to undergo surgical repair of degenerative mitral regurgitation. Echocardiography, including right ventricular strain analysis, was performed prior to, and one month and six months post mitral valve repair. Right ventricular strain that improved one month post-surgery was defined as reserved right ventricular. In addition, any cardiovascular outcomes comprising heart failure that required admission were recorded. The median follow-up duration is 31 months. Despite a significant improvement in mitral valve regurgitant volume post-operatively, left ventricular ejection fraction (LVEF) at six months was similar to LVEF at baseline. There was a transient decrease in LV longitudinal strain at one month that was recovered six months post mitral valve repair. Regarding the right ventricular, in contrast with conventional right ventricular parameters, including right ventricular tissue Doppler S', fractional area change and tricuspid annular plane systolic excursion (TAPSE), only resolution of right ventricular strain at one month predicted the subsequent myocardial recovery. Furthermore, patients with reserved right ventricular had a lower risk of hospitalization for heart failure compared to those with non-reserved right ventricular. Collectively, the early resolution of right ventricular strain is associated with the improvement in right ventricular function (measured by TAPSE) and in heart failure hospitalization in patients who had undergone surgical mitral valve repair for degenerative mitral regurgitation.

From the Editor's Desk…

From the Editor's Desk…