3D Imaging Reveals Complex Microvascular Remodeling in the Right Ventricle in Pulmonary Hypertension.

BACKGROUND: Pathogenic concepts of right ventricular (RV) failure in pulmonary arterial hypertension focus on a critical loss of microvasculature. However, the methods underpinning prior studies did not take into account the 3-dimensional (3D) aspects of cardiac tissue, making accurate quantification difficult. We applied deep-tissue imaging to the pressure-overloaded RV to uncover the 3D properties of the microvascular network and determine whether deficient microvascular adaptation contributes to RV failure. METHODS: Heart sections measuring 250-µm-thick were obtained from mice after pulmonary artery banding (PAB) or debanding PAB surgery and properties of the RV microvascular network were assessed using 3D imaging and quantification. Human heart tissues harvested at the time of transplantation from pulmonary arterial hypertension cases were compared with tissues from control cases with normal RV function. RESULTS: Longitudinal 3D assessment of PAB mouse hearts uncovered complex microvascular remodeling characterized by tortuous, shorter, thicker, highly branched vessels, and overall preserved microvascular density. This remodeling process was reversible in debanding PAB mice in which the RV function recovers over time. The remodeled microvasculature tightly wrapped around the hypertrophied cardiomyocytes to maintain a stable contact surface to cardiomyocytes as an adaptation to RV pressure overload, even in end-stage RV failure. However, microvasculature-cardiomyocyte contact was impaired in areas with interstitial fibrosis where cardiomyocytes displayed signs of hypoxia. Similar to PAB animals, microvascular density in the RV was preserved in patients with end-stage pulmonary arterial hypertension, and microvascular architectural changes appeared to vary by etiology, with patients with pulmonary veno-occlusive disease displaying a lack of microvascular complexity with uniformly short segments. CONCLUSIONS: 3D deep tissue imaging of the failing RV in PAB mice, pulmonary hypertension rats, and patients with pulmonary arterial hypertension reveals complex microvascular changes to preserve the microvascular density and maintain a stable microvascular-cardiomyocyte contact. Our studies provide a novel framework to understand microvascular adaptation in the pressure-overloaded RV that focuses on cell-cell interaction and goes beyond the concept of capillary rarefaction.

Collagen 18A1/Endostatin Expression in the Progression of Right Ventricular Remodeling and Dysfunction in Pulmonary Arterial Hypertension.

Numerous studies have demonstrated that endostatin (ES), a potent angiostatic peptide derived from collagen type XVIII α 1 chain and encoded by COL18A1, is elevated in pulmonary arterial hypertension (PAH). It is important to note that elevated ES has consistently been associated with altered hemodynamics, poor functional status, and adverse outcomes in adult and pediatric PAH. This study used serum samples from patients with Group I PAH and plasma and tissue samples derived from the Sugen/hypoxia rat pulmonary hypertension model to define associations between COL18A1/ES and disease development, including hemodynamics, right ventricle (RV) remodeling, and RV dysfunction. Using cardiac magnetic resonance imaging and advanced hemodynamic assessments with pressure-volume loops in patients with PAH to assess RV-pulmonary arterial coupling, we observed a strong relationship between circulating ES levels and metrics of RV structure and function. Specifically, RV mass and the ventricular mass index were positively associated with ES, whereas RV ejection fraction and RV-pulmonary arterial coupling were inversely associated with ES levels. Our animal data demonstrate that the development of pulmonary hypertension is associated with increased COL18A1/ES in the heart as well as the lungs. Disease-associated increases in COL18A1 mRNA and protein were most pronounced in the RV compared with the left ventricle and lung. COL18A1 expression in the RV was strongly associated with disease-associated changes in RV mass, fibrosis, and myocardial capillary density. These findings indicate that COL18A1/ES increases early in disease development in the RV and implicates COL18A1/ES in pathologic RV dysfunction in PAH.

Sex-dependent remodeling of right ventricular function in a rat model of pulmonary arterial hypertension.

Right ventricular (RV) function is an important prognostic indicator for pulmonary arterial hypertension (PAH), a vasculopathy that primarily and disproportionally affects women with distinct pre- and postmenopausal clinical outcomes. However, most animal studies have overlooked the impact of sex and ovarian hormones on RV remodeling in PAH. Here, we combined invasive measurements of RV hemodynamics and morphology with computational models of RV biomechanics in sugen-hypoxia (SuHx)-treated male, ovary-intact female, and ovariectomized female rats. Despite similar pressure overload levels, SuHx induced increases in end-diastolic elastance and passive myocardial stiffening, notably in male SuHx animals, corresponding to elevated diastolic intracellular calcium. Increases in end-systolic chamber elastance were largely explained by myocardial hypertrophy in male and ovary-intact female rats, whereas ovariectomized females exhibited contractility recruitment via calcium transient augmentation. Ovary-intact female rats primarily responded with hypertrophy, showing fewer myocardial mechanical alterations and less stiffening. These findings highlight sex-related RV remodeling differences in rats, affecting systolic and diastolic RV function in PAH.NEW & NOTEWORTHY Combining hemodynamic and morphological measurements from male, female, and ovariectomized female pulmonary arterial hypertension (PAH) rats revealed distinct adaptation mechanisms despite similar pressure overload. Males showed the most diastolic stiffening. Ovariectomized females had enhanced myocyte contractility and calcium transient upregulation. Ovary-intact females primarily responded with hypertrophy, experiencing milder passive myocardial stiffening and no changes in myocyte shortening. These findings suggest potential sex-specific pathways in right ventricular (RV) adaptation to PAH, with implications for targeted interventions.

Isoproterenol improves hemodynamics and right ventricle-pulmonary artery coupling after heart transplantation.

Right ventricular failure (RVF) is a major cause of early mortality after heart transplantation (HT). Isoproterenol (Iso) has chronotropic, inotropic, and vasodilatory properties, which might improve right ventricle function in this setting. We aimed to investigate the hemodynamic effects of isoproterenol on patients with post-HT RVF. We conducted a 1-yr retrospective observational study including patients receiving isoproterenol (Iso) and dobutamine for early RVF after HT. A comprehensive multiparametric hemodynamic evaluation was performed successively three times: no isoproterenol, low doses: 0.025 µg/kg/min, and high doses: 0.05 µg/kg/min (henceforth, respectively, called no Iso, low Iso, and high Iso). From June 2022 to June 2023, 25 patients, median [interquartile range (IQR) 25-75] age 54 [38-61] yr, were included. Before isoproterenol was introduced, all patients received dobutamine, and 15 (60%) were on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Isoproterenol significantly increased heart rate from 84 [77-99] (no Iso) to 91 [88-106] (low Iso) and 102 [90-122] beats/min (high Iso, P < 0.001). Similarly, cardiac index rose from 2.3 [1.4-3.1] to 2.7 [1.8-3.4] and 3 [1.9-3.7] L/min/m2 (P < 0.001) with a concomitant increase in indexed stroke volume (28 [17-34] to 31 [20-34] and 33 [23-35] mL/m2, P < 0.05). Effective pulmonary arterial elastance and pressures were not modified by isoproterenol. Pulmonary vascular resistance (PVR) tended to decrease from 2.9 [1.4-3.6] to 2.3 [1.3-3.5] wood units (WU), P = 0.06. Right ventricular ejection fraction/systolic pulmonary artery pressure (sPAP) evaluating right ventricle-pulmonary artery (RV-PA) coupling increased after isoproterenol from 0.8 to 0.9 and 1%·mmHg-1 (P = 0.001). In conclusion, in post-HT RVF, isoproterenol exhibits chronotropic and inotropic effects, thereby improving RV-PA coupling and resulting in a clinically relevant increase in the cardiac index.NEW & NOTEWORTHY This study offers a detailed and comprehensive hemodynamic investigation at the bedside, illustrating the favorable impact of isoproterenol on right ventricular-pulmonary arterial coupling and global hemodynamics. It elucidates the physiological effects of an underused inotropic strategy in a critical clinical scenario. By enhancing cardiac hemodynamics, isoproterenol has the potential to expedite right ventricular recovery and mitigate primary graft dysfunction, thereby reducing the duration of mechanical support and intensive care unit stay posttransplantation.

Transplantation, bridging, and support technologies in pulmonary hypertension.

Despite the progress made in medical therapies for treating pulmonary hypertension (PH), a subset of patients remain susceptible to developing a maladaptive right ventricular phenotype. The effective management of end-stage PH presents substantial challenges, necessitating a multidisciplinary approach and early identification of patients prone to acute decompensation. Identifying potential transplant candidates and assessing the feasibility of such a procedure are pivotal tasks that should be undertaken early in the treatment algorithm. Inclusion on the transplant list is contingent upon a comprehensive risk assessment, also considering the specific type of PH and various factors affecting waiting times, all of which should inform the decision-making process. While bilateral lung transplantation is the preferred option, it demands expert intra- and post-operative management to mitigate the heightened risks of pulmonary oedema and primary graft dysfunction in PH patients. Despite the availability of risk assessment tools, the occurrence of acute PH decompensation episodes can be unpredictable, potentially leading to refractory right ventricular failure even with optimal medical intervention, necessitating the use of rescue therapies. Advancements in right ventricular assist techniques and adjustments to graft allocation protocols for the most critically ill patients have significantly enhanced the survival in intensive care, affording the opportunity to endure while awaiting an urgent transplant. Given the breadth of therapeutic options available, specialised centres capable of delivering comprehensive care have become indispensable for optimising patient outcomes. These centres are instrumental in providing holistic support and management tailored to the complex needs of PH patients, ultimately enhancing their chances of a successful transplant and improved long-term prognosis.

Pathophysiology of the right ventricle and its pulmonary vascular interaction.

The right ventricle and its stress response is perhaps the most important arbiter of survival in patients with pulmonary hypertension of many causes. The physiology of the cardiopulmonary unit and definition of right heart failure proposed in the 2018 World Symposium on Pulmonary Hypertension have proven useful constructs in subsequent years. Here, we review updated knowledge of basic mechanisms that drive right ventricular function in health and disease, and which may be useful for therapeutic intervention in the future. We further contextualise new knowledge on assessment of right ventricular function with a focus on metrics readily available to clinicians and updated understanding of the roles of the right atrium and tricuspid regurgitation. Typical right ventricular phenotypes in relevant forms of pulmonary vascular disease are reviewed and recent studies of pharmacological interventions on chronic right ventricular failure are discussed. Finally, unanswered questions and future directions are proposed.

Poor cardiac output reserve in pulmonary arterial hypertension is associated with right ventricular stiffness and impaired interventricular dependence.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterised by poor exercise tolerance. The contribution of right ventricular (RV) diastolic function to the augmentation of cardiac output during exercise is not known. This study leverages pressure-volume (P-V) loop analysis to characterise the impact of RV diastology on poor flow augmentation during exercise in PAH. METHODS: RV P-V loops were measured in 41 PAH patients at rest and during supine bike exercise. Patients were stratified by median change in cardiac index (CI) during exercise into two groups: high and low CI reserve. Indices of diastolic function (end-diastolic elastance (E ed)) and ventricular interdependence (left ventricular transmural pressure (LVTMP)) were compared at matched exercise stages. RESULTS: Compared to patients with high CI reserve, those with low reserve exhibited lower exercise stroke volume (36 versus 49 mL·m-2; p=0.0001), with higher associated exercise afterload (effective arterial elastance (E a) 1.76 versus 0.90 mmHg·mL-1; p<0.0001), RV stiffness (E ed 0.68 versus 0.26 mmHg·mL-1; p=0.003) and right-sided pressures (right atrial pressure 14 versus 8 mmHg; p=0.002). Higher right-sided pressures led to significantly lower LV filling among the low CI reserve subjects (LVTMP -4.6 versus 3.2 mmHg; p=0.0001). Interestingly, low exercise flow reserve correlated significantly with high afterload and RV stiffness, but not with RV contractility nor RV-PA coupling. CONCLUSIONS: Patients with poor exercise CI reserve exhibit poor exercise RV afterload, stiffness and right-sided filling pressures that depress LV filling and stroke work. High afterload and RV stiffness were the best correlates to low flow reserve in PAH. Exercise unmasked significant pathophysiological PAH differences unapparent at rest.

Tricuspid regurgitation in pulmonary arterial hypertension: a right ventricular volumetric and functional analysis.

BACKGROUND: The consequences of tricuspid regurgitation (TR) for right ventricular (RV) function and prognosis in pulmonary arterial hypertension (PAH) are poorly described and effects of tricuspid valve repair on the RV are difficult to predict. METHODS: In 92 PAH patients with available cardiac magnetic resonance (CMR) studies, TR volume was calculated as the difference between RV stroke volume and forward stroke volume, i.e. pulmonary artery (PA) stroke volume. Survival was estimated from the time of the CMR scan to cardiopulmonary death or lung transplantation. In a subgroup, pressure-volume loop analysis including two-parallel elastances was applied to evaluate effective elastances, including net afterload (effective arterial elastance (E a)), forward afterload (effective pulmonary arterial elastance (E pa)) and backward afterload (effective tricuspid regurgitant elastance (E TR)). The effects of tricuspid valve repair were simulated using the online software package Harvi. RESULTS: 26% of PAH patients had a TR volume ≥30 mL. Greater TR volume was associated with increased N-terminal pro-brain natriuretic peptide (p=0.018), mean right atrial pressure (p<0.001) and RV end-systolic and -diastolic volume (both p<0.001). TR volume ≥30 mL was associated with a poor event-free survival (p=0.008). In comparison to E a, E pa correlated better with indices of RV dysfunction. Lower end-systolic elastance (E es) (p=0.002) and E TR (p=0.030), higher E pa (p=0.001) and reduced E es/E pa (p<0.001) were found in patients with a greater TR volume. Simulations predicted that tricuspid valve repair increases RV myocardial oxygen consumption in PAH patients with severe TR and low E es unless aggressive volume reduction is accomplished. CONCLUSIONS: In PAH, TR has prognostic significance and is associated with low RV contractility and RV-PA uncoupling. However, haemodynamic simulations showed detrimental consequences of tricuspid valve repair in PAH patients with low RV contractility.

Comparison of the stage-dependent mitochondrial changes in response to pressure overload between the diseased right and left ventricle in the rat.

The right ventricle (RV) differs developmentally, anatomically and functionally from the left ventricle (LV). Therefore, characteristics of LV adaptation to chronic pressure overload cannot easily be extrapolated to the RV. Mitochondrial abnormalities are considered a crucial contributor in heart failure (HF), but have never been compared directly between RV and LV tissues and cardiomyocytes. To identify ventricle-specific mitochondrial molecular and functional signatures, we established rat models with two slowly developing disease stages (compensated and decompensated) in response to pulmonary artery banding (PAB) or ascending aortic banding (AOB). Genome-wide transcriptomic and proteomic analyses were used to identify differentially expressed mitochondrial genes and proteins and were accompanied by a detailed characterization of mitochondrial function and morphology. Two clearly distinguishable disease stages, which culminated in a comparable systolic impairment of the respective ventricle, were observed. Mitochondrial respiration was similarly impaired at the decompensated stage, while respiratory chain activity or mitochondrial biogenesis were more severely deteriorated in the failing LV. Bioinformatics analyses of the RNA-seq. and proteomic data sets identified specifically deregulated mitochondrial components and pathways. Although the top regulated mitochondrial genes and proteins differed between the RV and LV, the overall changes in tissue and cardiomyocyte gene expression were highly similar. In conclusion, mitochondrial dysfuntion contributes to disease progression in right and left heart failure. Ventricle-specific differences in mitochondrial gene and protein expression are mostly related to the extent of observed changes, suggesting that despite developmental, anatomical and functional differences mitochondrial adaptations to chronic pressure overload are comparable in both ventricles.

Right Ventricular Dysfunction in Patients Undergoing High-Risk PCI with Impella.

BACKGROUND: Right ventricular dysfunction (RVD) is an important prognostic factor in several cardiac conditions, including acute and chronic heart failure. The impact of baseline RVD on clinical outcomes of patients undergoing high-risk percutaneous coronary intervention (HRPCI) supported by Impella is unknown. METHODS: Patients from the single-arm, multicenter PROTECT III study of Impella-supported HRPCI were stratified based on the presence or absence of RVD. RVD was quantitatively assessed by an echocardiography core laboratory and was defined as fractional area change < 35%, tricuspid annular plane systolic excursion < 17 mm or pulsed-wave Doppler S-wave of the lateral tricuspid annulus < 9.5 cm/s. Procedural outcomes, 90-day major adverse cardiac and cerebrovascular events (MACCE: the composite of all-cause mortality, myocardial infarction, stroke/TIA, and repeat revascularization), and 1-year mortality were assessed. RESULTS: Of the 239 patients who underwent RV function assessment, 124 were found to have RVD. Lower left ventricular ejection fraction, higher blood urea nitrogen levels, and more severe RV dilation were independently associated with RVD. The incidence of hypotensive episodes during PCI, the proportion of patients requiring prolonged Impella support, the completeness of revascularization, and the rate of in-hospital mortality did not differ significantly between patients with vs without RVD. However, 90-day MACCE rates were higher in those with RVD, and RVD was a robust predictor of 1-year mortality in multivariable Cox-regression analyses. CONCLUSION: In patients undergoing HRPCI with Impella, RVD was associated with more advanced biventricular failure. The use of Impella support during HRPCI facilitated effective revascularization, even in those with concomitant RVD. Nevertheless, RVD was associated with unfavorable long-term prognoses.

Impact of Right Ventricular Dysfunction on Outcomes in Acute Myocardial Infarction and Cardiogenic Shock: Insights from the National Cardiogenic Shock Initiative.

BACKGROUND: Right ventricular dysfunction (RVD) complicates 30%-40% of cases in acute myocardial infarction (AMI) and cardiogenic shock (CS). There are sparse data on the effects of RVD on outcomes and the impact of providing early left ventricular (LV) mechanical circulatory support (MCS) on RV function and hemodynamics. METHODS AND RESULTS: Between July 2016 and December 2020, 80 sites participated in the study. All centers agreed to treat patients with AMI-CS using a standard protocol emphasizing invasive hemodynamic monitoring and rapid initiation of LV-MCS. RVD was defined as a right atrial (RA) pressure of >12 mm Hg and a pulmonary artery pulsatility index (PAPI) of <1 within 24 hours of the index procedure. The primary outcome was survival to discharge. In a subgroup analysis, data available from the Automated Impella Controller console was used to analyze diastolic suction alarms from LV placement signal and its relation to RVD. A total of 361 patients were included in the analysis, of whom 28% had RVD. The median age was 64 years (interquartile range 55-72 years), 22.7% were female and 75.7% were White. There was no difference in age, sex, or comorbidities between those with or without RVD. Patients with RVD had a higher probability of active CPR during LV-MCS implant (14.7% vs 6.3%), Society for Cardiovascular Angiography and Interventions stage E shock (39.2% vs 23.2%), and higher admission lactate levels (5.1 mg/dL vs 3.0 mg/dL). Survival to discharge was significantly lower among those with RVD (61.8% vs 73.4%, odds ratio 0.89, 95% confidence interval 0.36-0.95, P = .031). This association remained significant in the multivariate analysis. There was no significant difference in hemodynamic variables within 24 hours of LV-MCS support among those with or without RVD. At 24 hours, patients with a CPO of >0.6 W and a PAPi of >1 had a trend toward better survival to discharge compared with those with a CPO of ≤0.6 W and a PAPi of ≤1 (77.1% vs 54.6%, P = .092). Patients with RVD were significantly more likely to have diastolic suction alarms within 24 hours of LV-MCS initiation. CONCLUSIONS: RVD in AMI-CS is common and associated with worse survival to discharge. Early LV-MCS decreases filling pressures rapidly within the first 24 hours and decreases the rate of RVD. Achieving a CPO of >0.6 W and a PAPi of >1 within 24 hours is associated with high survival. Diastolic suction alarms may have usefulness as an early marker of RVD.

The right ventricular dysfunction and ventricular interdependence in patients with T2DM and aortic regurgitation: an assessment using CMR feature tracking.

BACKGROUND: Patients with concomitant type 2 diabetes mellitus (T2DM) and aortic regurgitation (AR) can present with right ventricular (RV) dysfunction. The current study aimed to evaluate the impact of AR on RV impairment and the importance of ventricular interdependence using cardiac magnetic resonance feature tracking (CMR­FT) in patients with T2DM. METHODS: This study included 229 patients with T2DM (AR-), 88 patients with T2DM (AR+), and 122 healthy controls. The biventricular global radial strain (GRS), global circumferential strain (GCS), and global longitudinal peak strain (GLS) were calculated with CMR­FT and compared among the healthy control, T2DM (AR-), and T2DM (AR+) groups. The RV regional strains at the basal, mid, and apical cavities between the T2DM (AR+) group and subgroups with different AR degrees were compared. Backward stepwise multivariate linear regression analyses were performed to determine the effects of AR and left ventricular (LV) strains on RV strains. RESULTS: The RV GLS, LV GRS, LV GCS, LV GLS, interventricular septal (IVS) GRS and IVS GCS were decreased gradually from the controls through the T2DM (AR-) group to the T2DM (AR+) group. The IVS GLS of the T2DM (AR-) and T2DM (AR+) groups was lower than that of the control group. AR was independently associated with LV GRS, LV GCS, LV GLS, RV GCS, and RV GLS. If AR and LV GLSs were included in the regression analyses, AR and LV GLS were independently associated with RV GLS. CONCLUSION: AR can exacerbate RV dysfunction in patients with T2DM, which may be associated with the superimposed strain injury of the left ventricle and interventricular septum. The RV longitudinal and circumferential strains are important indicators of cardiac injury in T2DM and AR. The unfavorable LV-RV interdependence supports that while focusing on improving LV function, RV dysfunction should be monitored and treated in order to slow the progression of the disease and the onset of adverse outcomes.

Impact of diabetes mellitus on right ventricular dysfunction and ventricular interdependence in hypertensive patients with heart failure with reduced ejection fraction assessed via 3.0 T cardiac MRI.

BACKGROUND: Hypertension (HTN) and diabetes mellitus (DM) are two common comorbidities of heart failure with reduced ejection fraction (HFrEF), each of which can cause right ventricular (RV) dysfunction. The aim of this study was to investigate the impact of DM on RV dysfunction and ventricular interdependence in hypertensive HFrEF patients via cardiac magnetic resonance imaging (MRI) feature tracking. METHODS: This study included 249 patients with HFrEF: 77 HFrEF controls, 97 with hypertensive HFrEF (HTN-HFrEF [DM-]) and 75 with hypertensive HFrEF and comorbid DM (HTN-HFrEF [DM+]). The cardiac MRI-derived biventricular global radial (GRS), circumferential (GCS) and longitudinal (GLS) peak strains were obtained and compared among the groups. Multivariable linear regression and mediation analyses were used to evaluate the effects of DM and left ventricular (LV) strain on RV strain. RESULTS: The biventricular GLS and GLS of segments 8, 9 and 14 of the interventricular septum (IVS) decreased gradually from the HFrEF control group to the HTN-HFrEF (DM-) group to the HTN-HFrEF (DM+) group (all P < 0.05). Patients with DM had even lower biventricular GCS and IVS strains in all directions in specific segments than did those without DM and the HFrEF controls (all P < 0.05). DM was independently associated with impaired RVGLS and RVGCS (both P < 0.05) in hypertensive HFrEF patients. The difference in RVGLS between the hypertensive HFrEF subgroups was partly mediated by LVGLS [ß = 0.80, 95% CI (0.39-1.31)], and that of RVGCS was partly mediated by LVGCS [ß = 0.28, 95% CI (0.01-0.62)]. CONCLUSIONS: In hypertensive HFrEF patients, comorbid DM may have aggravated RV dysfunction and was an independent determinant of impaired RV strain. RV dysfunction might be directly affected by DM and partially mediated by LV strain through unfavorable ventricular independence.

Use of percutaneous mechanical circulatory support for right ventricular failure.

BACKGROUND: Utilization of right ventricular mechanical circulatory support (RV-MCS) devices has been limited by a lack of recognition of RV failure as well as a lack of availability and experience with RV-MCS. AIMS: We report a single-center experience with the use of percutaneous RV-MCS and report predictors of adverse outcomes. METHODS: This was a single-center retrospective cohort study. Data from consecutive patients who received RV-MCS for any indication between June 2015 and January 2022 were included. Data on baseline comorbidities, hemodynamics, and laboratory values were collected. The primary outcome was in-hospital mortality analyzed as a logistic outcome in a multivariable model. These variables were further ranked by their predictive value. RESULTS: Among 58 consecutive patients enrolled, the median age was 66 years, 31% were female and 53% were white. The majority of the patients (48%) were hospitalized for acute on chronic heart failure. The majority of the patients were SCAI SHOCK Stage D (67%) and 34 (64%) patients had MCS placed within 24 h of the onset of shock. Before placement of RV-MCS, median central venous pressure (CVP) and RV stroke work index were 20 mmHg and 8.9 g m/m2, respectively. Median serum lactate was 3.5 (1.6, 6.2) mmol/L. Impella RP was implanted in 50% and ProtekDuo in the remaining 50%. Left ventricular MCS was concomitantly used in 66% of patients. Twenty-eight patients (48.3%) died. In these patients, median serum lactate was significantly higher (4.1 [2.3, 13.0] vs. 2.2 [1.4, 4.0] mmol/L, p = 0.007) and a trend toward higher median CVP (24 [18, 31] vs. 19 [14, 24] mmHg, p = 0.052). In the multivariable logistic model, both serum lactate and CVP before RV-MCS placement were independent predictors of in-hospital mortality. Serum lactate had the highest predictive value. CONCLUSION: In our real-world cohort, 52% of patients treated with RV-MCS survived their index hospitalization. Serum lactate at presentation and CVP were the strongest predictors of in-hospital mortality.

The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries.

BACKGROUND: Unilateral pulmonary artery (PA) stenosis is common in the transposition of the great arteries (TGA) after arterial switch operation (ASO) but the effects on the right ventricle (RV) remain unclear. AIMS: To assess the effects of unilateral PA stenosis on RV afterload and function in pediatric patients with TGA-ASO. METHODS: In this retrospective study, eight TGA patients with unilateral PA stenosis underwent heart catheterization and cardiac magnetic resonance (CMR) imaging. RV pressures, RV afterload (arterial elastance [Ea]), PA compliance, RV contractility (end-systolic elastance [Ees]), RV-to-PA (RV-PA) coupling (Ees/Ea), and RV diastolic stiffness (end-diastolic elastance [Eed]) were analyzed and compared to normal values from the literature. RESULTS: In all TGA patients (mean age 12 ± 3 years), RV afterload (Ea) and RV pressures were increased whereas PA compliance was reduced. RV contractility (Ees) was decreased resulting in RV-PA uncoupling. RV diastolic stiffness (Eed) was increased. CMR-derived RV volumes, mass, and ejection fraction were preserved. CONCLUSION: Unilateral PA stenosis results in an increased RV afterload in TGA patients after ASO. RV remodeling and function remain within normal limits when analyzed by CMR but RV pressure-volume loop analysis shows impaired RV diastolic stiffness and RV contractility leading to RV-PA uncoupling.

Novel interventions on the tricuspid valve: how to consider the pulmonary circulation?

PURPOSE OF REVIEW: This review addresses treatment options for moderate to severe tricuspid valve regurgitation and the importance of right ventricular function and the pulmonary circulation. RECENT FINDINGS: Several interventional treatment options for severe tricuspid regurgitation have been developed including transcatheter edge-to-edge repair, annuloplasty and valve replacement. So far, transcatheter edge-to-edge repair is most frequently used with procedural success rates of more than 95% and improvements in functional and quality of life parameters for up to 2 years. Right ventricular function as well as pulmonary artery pressure and resistance levels are important outcome predictors. Mean pulmonary artery pressure more than 30 mmHg, transpulmonary gradient more than 17 mmHg and right ventricular to pulmonary artery coupling ratio less than 0.406 indicate poor outcome. SUMMARY: Despite the remarkable safety of interventional treatment of severe tricuspid regurgitation right ventricular dysfunction and abnormal pulmonary hemodynamics are important determinants of procedural success and clinical outcome.Complete hemodynamic work-up should be an integral part of prerepair assessment although validated data predicting outcome are limited.

Assessment of right ventricular diastolic function in pediatric patients with repaired tetralogy of Fallot by cardiovascular magnetic resonance and echocardiography.

OBJECTIVES: Cardiovascular magnetic resonance (CMR) imaging is routinely performed for assessing right ventricular (RV) systolic but not diastolic function. We aimed to investigate CMR-based assessment of RV diastolic function in pediatric patients with repaired tetralogy of Fallot (rTOF), compared to transthoracic echocardiography (TTE) measurements. METHODS: A total of 130 consecutive pediatric patients with rTOF who underwent clinically indicated CMR and same-day TTE were included. Forty-three controls were recruited. Phase-contrast images were used to measure trans-tricuspid valve flow velocities during early (E) and late diastolic (A) phases (measured in cm/s). Feature tracking of the tricuspid annulus was performed to derive early (e') and late diastolic (a') myocardial velocities (measured in cm/s). RV diastolic function was evaluated by E/A ratio, E/e' ratio, and E-wave deceleration time (measured in milliseconds). Regression analyses were utilized to identify potential variables associated with RV diastolic dysfunction (DD). The performance of CMR-derived parameters in diagnosing RV DD was assessed using receiver-operating characteristic analyses. RESULTS: Good agreement was found between CMR and TTE measurements (ICC 0.70-0.89). Patients with RV DD (n = 67) showed significantly different CMR-derived parameters including E and e' velocities, and E/A and E/e' ratio, compared to patients without DD (n = 63) (all p < 0.05). CMR-derived E and e' velocities and E/e' ratio were independent predictors of RV DD. E/e' of 5.8 demonstrated the highest discrimination of RV DD (AUC 0.76, sensitivity 70%, specificity 86%). CONCLUSIONS: CMR-derived parameters showed good agreement with TTE parameters in determining RV DD. CMR-derived E/e' was proved to be the most effective in identifying RV DD. CLINICAL RELEVANCE STATEMENT: This study demonstrated the feasibility and efficacy of CMR in assessing diastolic function in pediatric patients. RV DD was presented in over half of patients according to current TTE guidelines, highlighting the need for assessing RV diastolic function during follow-up. KEY POINTS: • Routinely acquired cine and phase-contrast cardiovascular magnetic resonance (CMR) images yielded right ventricular (RV) diastolic parameters which demonstrated good agreement with transthoracic echocardiography (TTE) measurements. • There was a high prevalence of RV diastolic function impairment in pediatric patients with repaired tetralogy of Fallot (rTOF). • CMR is a reliable complementary modality of TTE for RV diastolic function evaluation.

Sulforaphane Improves Redox Homeostasis and Right Ventricular Contractility in a Model of Pulmonary Hypertension.

ABSTRACT: Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance (PVR), imposing overload on the right ventricle (RV) and imbalance of the redox state. Our study investigated the influence of treatment with sulforaphane (SFN), found in cruciferous vegetables, on RV remodeling and redox homeostasis in monocrotaline (MCT)-induced PAH. Male Wistar rats were separated into 4 groups: control (CTR); CTR + SFN; MCT; and MCT + SFN. PAH induction was implemented by a single dose of MCT (60 mg/kg intraperitoneally). Treatment with SFN (2.5 mg/kg/day intraperitoneally) started on the seventh day after the MCT injection and persisted for 2 weeks. After 21 days of PAH induction, echocardiographic, hemodynamic, and oxidative stress evaluation was performed. The MCT group showed an increase in RV hypertrophy, RV systolic area, RV systolic, mean pulmonary artery pressure, and PVR and exhibited a decrease in the RV outflow tract acceleration time/ejection time ratio, RV fractional shortening, and tricuspid annular plane systolic excursion compared to CTR ( P < 0.05). SFN-treated PAH attenuated detrimental changes in tricuspid annular plane systolic excursion, mean pulmonary artery pressure, and PVR parameters. Catalase levels and the glutathione/Glutathione disulfide (GSSG) ratio were diminished in the MCT group compared to CTR ( P < 0.05). SFN increased catalase levels and normalized the glutathione/GSSG ratio to control levels ( P < 0.05). Data express the benefit of SFN treatment on the cardiac function of rats with PAH associated with the cellular redox state.

Right Ventricular "Bubble Time" to Identify Patients With Right Ventricular Dysfunction.

STUDY OBJECTIVE: We propose a novel method of evaluating right ventricular (RV) dysfunction in the emergency department (ED) using RV "bubble time"-the duration of time bubbles from a saline solution flush are visualized in the RV on echocardiography. The objective was to identify the optimal cutoff value for RV bubble time that differentiates patients with RV dysfunction and report on its diagnostic test characteristics. METHODS: This prospective diagnostic accuracy study enrolled a convenience sample of hemodynamically stable patients in the ED. A sonographer administered a 10-mL saline solution flush into the patient's intravenous catheter, performed a bedside echocardiogram, and measured RV bubble time. Subsequently, the patient underwent a comprehensive cardiologist-interpreted echocardiogram within 36 hours, which served as the gold standard. Patients with RV strain or enlargement of the latter found on an echocardiogram were considered to have RV dysfunction. Bubble time was evaluated by a second provider, blinded to the initial results, who reviewed the ultrasound clips. The primary outcome measure was the optimal cutoff value of RV bubble time that identifies patients with and without RV dysfunction. RESULTS: Of 196 patients, median age was 67 year, and half were women, with 69 (35.2%) having RV dysfunction. Median RV bubble time among patients with RV dysfunction was 62 seconds (interquartile range [IQR]: 52, 93) compared with 21 seconds (IQR: 12, 32) among patients without (P<.0001). The optimal cutoff value of RV bubble time for identifying patients with RV dysfunction was 40 or more seconds, with a sensitivity of 0.97 (95% CI 0.93 to 1.00) and specificity of 0.87 (95% CI 0.82 to 0.93). CONCLUSION: In patients in the ED, an RV bubble time of 40 or more seconds had high sensitivity in identifying patients with RV dysfunction, whereas an RV bubble time of less than 40 seconds had good specificity in identifying patients without RV dysfunction. These findings warrant further investigation in undifferentiated patient populations and by emergency physicians without advanced ultrasound training.

The effect of pulmonary hypertension and right ventricular dysfunction on early mortality and morbidity in patients undergoing mitral valve replacement.

INTRODUCTION: The indications for concominant tricuspid valve surgery in patients undergoing mitral valve surgery for rheumatic reasons are limited. The aim of our study was to investigate the effects of severe pulmonary hypertension and low TAPSE values on early-term mortality and morbidity in patients undergoing mitral valve replacement. METHODS: The data of all patients who underwent mitral valve replacement between January 2013 and August 2020 were examined retrospectively. Patients were divided into 2 groups according to pulmonary artery pressure (PAP ≥ 50 and PAP < 50). The group with PAP > 50 was then divided into 2 subgroups according to TAPSE (1.5 ≥ or < 1.5) values. The early-term mortality and morbidity rates of these groups were compared. RESULTS: Seventy-nine patients who underwent mitral valve replacement were included in the study. Fifty-four (68%) of them were female, and 25 (32%) were male. During the preoperative period, the TAPSE was 16.8 ± 3.0 mm, and the PAP was 52.1 ± 14.1 mmHg. There were 53 patients with PAP > 50 and 26 patients with PAP < 50. In the PAP > 50 group, the rates of tricuspid regurgitation (p < 0.001), blood transfusion (p < 0.001), intensive care unit stay (p < 0.001), need for CPAP (p = 0.043), reintubation (p = 0.048), acute renal failure (p = 0.028), and mortality (p = 0.026) were found to be significantly different. CONCLUSION: In conclusion, we believe that in patients with mitral valve pathology, early referral for surgical intervention, before the pulmonary pressures significantly increase and right ventricular function deteriorates, can enhance survival outcomes.