Right ventricular dysfunction and failure in chronic pressure overload

Traditional and Advanced Echocardiographic Evaluation in Chronic Obstructive Pulmonary Disease: The Forgotten Relation

Chronic obstructive pulmonary disease (COPD) is a significant preventable and treatable clinical disorder defined by a persistent, typically progressive airflow obstruction. This disease has a significant negative impact on mortality and morbidity worldwide. However, the complex interaction between the heart and lungs is usually underestimated, necessitating more attention to improve clinical outcomes and prognosis. Indeed, COPD significantly impacts ventricular function, right and left chamber architecture, tricuspid valve functionality, and pulmonary blood vessels. Accordingly, more emphasis should be paid to their diagnosis since cardiac alterations may occur very early before COPD progresses and generate pulmonary hypertension (PH). Echocardiography enables a quick, noninvasive, portable, and accurate assessment of such changes. Indeed, recent advancements in imaging technology have improved the characterization of the heart chambers and made it possible to investigate the association between a few cardiac function indexes and clinical and functional aspects of COPD. This review aims to describe the intricate relation between COPD and heart changes and provide basic and advanced echocardiographic methods to detect early right ventricular and left ventricular morphologic alterations and early systolic and diastolic dysfunction. In addition, it is crucial to comprehend the clinical and prognostic significance of functional tricuspid regurgitation in COPD and PH and the currently available transcatheter therapeutic approaches for its treatment. Moreover, it is also essential to assess noninvasively PH and pulmonary resistance in patients with COPD by applying new echocardiographic parameters. In conclusion, echocardiography should be used more frequently in assessing patients with COPD because it may aid in discovering previously unrecognized heart abnormalities and selecting the most appropriate treatment to improve the patient's symptoms, quality of life, and survival.

Myocardial Matrix Hydrogels Mitigate Negative Remodeling and Improve Function in Right Heart Failure Model

This study evaluates the effectiveness of myocardial matrix (MM) hydrogels in mitigating negative right ventricular (RV) remodeling in a rat model of RV heart failure. The goal was to assess whether a hydrogel derived from either the right or left ventricle could promote cardiac repair. Injured rat right ventricles were injected with either RV-or left ventricular-derived MM hydrogels. Both hydrogels improved RV function and morphology and reduced negative remodeling. This study supports the potential of injectable biomaterial therapies for treating RV heart failure.

A simply calculated nutritional index provides clinical implications in patients undergoing transcatheter aortic valve replacement

BACKGROUND

Malnutrition is associated with adverse outcomes in patients with aortic stenosis. The Triglycerides × Total Cholesterol × Body Weight Index (TCBI) is a simple scoring model to evaluate the status of nutrition. However, the prognostic relevance of this index in patients undergoing transcatheter aortic valve replacement (TAVR) is unknown. This study aimed to evaluate the association of the TCBI with clinical outcomes in patients undergoing TAVR.

METHODS

A total of 1377 patients undergoing TAVR were evaluated in this study. The TCBI was calculated by the formula; triglyceride (mg/dL) × total cholesterol (mg/dL) × body weight (kg)/1000. The primary outcome was all-cause mortality within 3 years.

RESULTS

Patients with a low TCBI, based on a cut-off value of 985.3, were more likely to have elevated right atrial pressure (p = 0.04), elevated right ventricular pressure (p < 0.01), right ventricular systolic dysfunction (p < 0.01), tricuspid regurgitation ≥ moderate (p < 0.01). Patients with a low TCBI had a higher cumulative 3-year all-cause (42.3% vs. 31.6%, p < 0.01; adjusted HR 1.36, 95% CI 1.05-1.77, p = 0.02) and non-cardiovascular mortality (15.5% vs. 9.1%, p < 0.01; adjusted HR 1.95, 95% CI 1.22-3.13, p < 0.01) compared to those with a high TCBI. Adding a low TCBI to EuroSCORE II improved the predictive value for 3-year all-cause mortality (net reclassification improvement, 0.179, p < 0.01; integrated discrimination improvement, 0.005, p = 0.01).

CONCLUSION

Patients with a low TCBI were more likely to have right-sided heart overload and exhibited an increased risk of 3-year mortality. The TCBI may provide additional information for risk stratification in patients undergoing TAVR.

The Right Ventricle: From Embryologic Development to RV Failure

PURPOSE OF REVIEW

The right ventricle (RV) and left ventricle (LV) have different developmental origins, which likely plays a role in their chamber-specific response to physiological and pathological stress. RV dysfunction is encountered frequently in patients with congenital heart disease (CHD) and right heart abnormalities emerge from different causes than increased afterload alone as is observed in RV dysfunction due to pulmonary hypertension (PH). In this review, we describe the developmental, structural, and functional differences between ventricles while highlighting emerging therapies for RV dysfunction.

RECENT FINDINGS

There are new insights into the role of fibrosis, inflammation, myocyte contraction, and mitochondrial dynamics in the pathogenesis of RV dysfunction. We discuss the current state of therapies that may potentially improve RV function in both experimental and clinical trials. A clearer understanding of the differences in molecular alterations in the RV compared to the LV may allow for the development of better therapies that treat RV dysfunction.

Baseline PA/BSA ratio in patients undergoing transcatheter aortic valve replacement - A novel CT-based marker for the prediction of pulmonary hypertension and outcome

BACKGROUND

Pulmonary hypertension (pH) has a prognostic impact on patients undergoing transcatheter aortic valve replacement (TAVR). Pulmonary artery (PA) dilatation assessed by multidetector computed tomography (MDCT) has the potential to predict PH. The aim of the study was to evaluate the clinical parameters associated with PA dilatation and to investigate its prognostic relevance in patients undergoing TAVR.

METHODS

In 770 patients undergoing TAVR between February 2016 and July 2019, PA diameter was measured by MDCT before TAVR. Additionally, PA diameter divided by ascending aorta diameter or body surface area (BSA) was calculated.

RESULTS

Of all the CT-derived parameters compared with a receiver operating characteristic curve, the value for PA/BSA with a median of 1.68 (IQR 1.47, 1.91) cm/m2 showed the greatest area-under-the-curve (0.75) for predicting PH at baseline. Based on this median, patients were assigned to a small PA/BSA (n = 386) or a large PA/BSA (n = 384) group. Hereby, a large PA/BSA was independently associated with PH at baseline (OR:8.39 [5.36-13.14], p < 0.001) and after TAVR (OR:1.73 [1.18-2.53], p = 0.005). A large PA/BSA was associated with a significantly higher cumulative two-year all-cause mortality compared to small PA/BSA (30.0% vs. 13.7%, p < 0.001), which was supported in the multivariable model (HR:1.87; 95%CI, 1.12-3.04; p = 0.017).

CONCLUSION

Patients with a large PA/BSA on MDCT are more likely to have PH at baseline and after TAVR. Large PA/BSA is associated with an increased risk of mortality and could provide additional information for risk stratification in patients undergoing TAVR.

Impact of Pulmonary Artery Dilatation on Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement

OBJECTIVES

The aim of this study was to evaluate the clinical impact of computed tomography (CT)-derived pulmonary artery dilatation (PAD) in patients undergoing transcatheter aortic valve replacement (TAVR).

BACKGROUND

Several studies have reported an association between pulmonary hypertension and cardiovascular events, but the prognostic value of PAD in patients undergoing TAVR remains unclear.

METHODS

The preprocedural computed tomographic studies of patients who underwent TAVR at Cedars-Sinai Medical Center between November 2013 and December 2017 were analyzed. Patients were divided into 2 groups according to the presence of PAD assessed on CT (pulmonary artery [PA] diameter ≥29 mm). The primary endpoint was all-cause mortality at 2 years.

RESULTS

A total of 895 patients were included (mean age 81.3 ± 8.5 years), with a mean Society of Thoracic Surgeons score of 4.8%. The median PA diameter was 28.0 mm, and PAD was observed in 369 patients (41.2%). Compared with the no-PAD group, the PAD group had higher Society of Thoracic Surgeons scores and higher rates of atrial fibrillation, chronic kidney disease, and chronic obstructive pulmonary disease. The PAD group had higher 2-year all-cause mortality than the no-PAD group (28.9% vs 12.8%; P < 0.001), and PAD was independently associated with mortality (adjusted HR: 2.21; 95% CI: 1.44-3.39; P < 0.001). Furthermore, PAD had strong prognostic power in the subgroup analysis, stratified according to PA pressure (>36 mm Hg).

CONCLUSIONS

CT-derived PAD is a significant prognostic factor in patients undergoing TAVR.

Right cardiac involvement in lung diseases: a multimodality approach from diagnosis to prognostication

Lung diseases are amongst the main healthcare issues in the general population, having a high burden of morbidity and mortality. The cardiovascular system has a key role in patients affected by respiratory disorders. More specifically, the right ventricle (RV) enables the impaired lung function to be overcome in an initial stage of disease process, reducing the severity of dyspnoea. In addition, two of the main causes of death in this setting are RV failure and sudden cardiac death (SCD). Echocardiography is regarded as a useful and easily available tool in assessing RV function. Several noninvasive echocardiographic parameters of elevated pulmonary pressures and RV function have been proposed. The combination of different parameters and imaging methods is paramount and researches regarding RV impairment using these indices has been specifically addressed in relation to the chronic obstructive and restrictive lung disease in order to guide the clinicians in the management of these patients. Cardiac involvement in lung diseases is often observed, and RV changes are reported also in early stages of pulmonary diseases. The role of right ventricle in chronic respiratory disease patients has to be evaluated in detail to describe the response to therapy and the degree of disease progression through multimodality and advanced imaging techniques. The aim of this review is to describe the different pathophysiological mechanisms of cardiac impairment in primary lung disease (such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and sarcoidosis) and to summarize the role of cardiac multimodality imaging in the diagnosis and the prognosis of these diseases.

Right ventricular dysfunction assessed by cardiovascular magnetic resonance is associated with poor outcome in patients undergoing transcatheter mitral valve repair

Aims

To evaluate whether CMR-derived RV assessment can facilitate risk stratification among patients undergoing transcatheter mitral valve repair (TMVR).

Background

In patients undergoing TMVR, only limited data exist regarding the role of RV function. Previous studies assessed the impact of pre-procedural RV dysfunction stating that RV failure may be associated with increased cardiovascular mortality after the procedure.

Methods

Sixty-one patients underwent CMR, echocardiography and right heart catheterization prior TMVR. All-cause mortality and heart failure hospitalizations were assessed during 2-year follow-up.

Results

According to RV ejection fraction (RVEF) <46%, 23 patients (38%) had pre-existing RV dysfunction. By measures of RV end-diastolic volume index (RVEDVi), 16 patients (26%) revealed RV dilatation. Nine patients (15%) revealed both. RV dysfunction was associated with increased right and left ventricular volumes as well as reduced left ventricular (LV) ejection fraction (all p<0.05). During follow-up, 15 patients (25%) died and additional 14 patients (23%) were admitted to hospital due to heart failure symptoms. RV dysfunction predicted all-cause mortality even after adjustment for LV function. Similarly, RVEDVi was a predictor of all-cause mortality even after adjustment for LVEDVi. Kaplan-Meier survival analysis unraveled that, among patients presenting with CMR indicative of both, RV dysfunction and dilatation, the majority (78%) experienced an adverse event during follow-up (p<0.001).

Conclusion

In patients undergoing TMVR, pre-existing RV dysfunction and RV dilatation are associated with reduced survival, in progressive additive fashion. The assessment of RV volumes and function by CMR may aid in risk stratification prior TMVR in these high-risk patients.

Pathophysiology of Acute and Chronic Right Heart Failure

Right-sided heart failure (RHF) occurs from impaired contractility of the right ventricle caused by pressure, volume overload, or intrinsic myocardial contractile dysfunction. The development of subclinical right ventricle (RV) dysfunction or overt RHF is a negative prognostic indicator. Recent attention has focused on RV-specific inflammatory growth factors and mediators of myocardial fibrosis to elucidate the mechanisms leading to RHF and potentially guide the development of novel therapeutics. This article focuses on the distinct changes in RV structure, mechanics, and function, as well as molecular and inflammatory mediators involved in the pathophysiology of acute and chronic RHF.

Right ventricular dimension index by cardiac magnetic resonance for prognostication in connective tissue diseases and pulmonary hypertension

OBJECTIVES

Pulmonary hypertension (PH) in patients with CTD is a heterogeneous condition affected by left heart disease, chronic lung disease and thromboembolism as well as pulmonary vascular disease. Recent studies using cardiac magnetic resonance (CMR) have shown that right ventricular dysfunction is predictive for mortality in patients with PH, but limited to pulmonary arterial hypertension. This study aimed to analyse prognostic factors in PH-CTD.

METHODS

This retrospective analysis comprised 84 CTD patients, including SSc, who underwent both CMR and right heart catheterization from 2008 to 2018. Demographics, laboratory findings, and haemodynamic and morphological parameters were extracted. The prognostic value of each parameter was evaluated by multivariate analysis using covariables derived from propensity score to control confounding factors.

RESULTS

Of 84 patients, 65 had right heart catheterization-confirmed PH (54 pulmonary arterial hypertension, 11 non-pulmonary arterial hypertension). Nine out of these PH patients died during a median follow-up period of 25 months. In 65 patients with PH, right ventricular end-diastolic dimension index (RVEDDI) evaluated by CMR was independently associated with mortality (hazard ratio 1.24; 95% CI: 1.08-1.46; P = 0.003). In a receiver operating characteristic analysis, RVEDDI highly predicted mortality, with area under the curve of 0.87. The 0.5-2-year follow-up data revealed that RVEDDI in both survivors and non-survivors did not significantly change over the clinical course, leading to the possibility that an early determination of RVEDDI could predict the prognosis.

CONCLUSION

RVEDDI simply evaluated by CMR could serve as a significant predictor of mortality in PH-CTD. A further validation cohort study is needed to confirm its usability.

Tricuspid annular plane systolic excursion is correlated with poor outcome in surgery for rheumatic heart valvular disease

BACKGROUND

Right ventricular (RV) function is a major determinant of clinical outcome, but its function indices have not been studied well in surgery for rheumatic valvular heart disease. The aim of this study was to determine the correlation of tricuspid annular plane systolic excursion (TAPSE) with outcome of rheumatic heart valve surgery.

METHODS

A prospective comparative study was conducted including 100 eligible patients who were divided into two groups based on RV function as assessed by TAPSE measured by two-dimensional (2D) echocardiography preoperatively. Those with TAPSE less than 15 mm were included in group 1 and those with TAPSE of 15 or more were included in group 2.

RESULTS

50 patients were included in group 1 and 50 patients in group 2. Mean age of the patients was 56.78 ± 15.21 years in group 1 and 54.46 ± 15.03 years in group 2 (P = 0.444). 34 (34%) patients underwent aortic valve replacement (AVR), 35 (35%) underwent both aortic and mitral valves replacement, and 31 (31%) ones had mitral valve replacement (MVR). A significant difference was found between the duration of ventilation (5.15 ± 2.80 hours in group 1 vs. 3.72 ± 2.71 hours in group 2, P = 0.001), postoperative inotropic requirement [more than 24 hours in 18 (36%) patients in group 1 vs. 7 (14%) patients in group 2, P = 0.003], total intensive care unit (ICU) stay (8.92 ± 3.62 days in group 1 vs. 5.20 ± 2.06 days in group 2, P = 0.001), and mortality [7 (14%) in group 1 vs. 2 (4%) in group 2, P = 0.038].

CONCLUSION

TAPSE less than 15 mm in patients undergoing surgical correction for rheumatic valvular heart disease leads to poor outcomes. These patients need special attention perioperatively.

Inhaled levosimendan versus intravenous levosimendan in patients with pulmonary hypertension undergoing mitral valve replacement

Context:

Inhaled levosimendan may act as selective pulmonary vasodilator and avoid systemic side effects of intravenous levosimendan, which include decrease in systemic vascular resistance (SVR) and systemic hypotension, but with same beneficial effect on pulmonary artery pressure (PAP) and right ventricular (RV) function.

Aim:

The aim of this study was to compare the effect of inhaled levosimendan with intravenous levosimendan in patients with pulmonary hypertension undergoing mitral valve replacement.

Settings and Design:

The present prospective randomized comparative study was conducted in a tertiary care hospital.

Subjects and Methods:

Fifty patients were randomized into two groups (n = 25). Group A: Levosimendan infusion was started immediately after coming-off of cardiopulmonary bypass and continued for 24 h at 0.1 mcg/kg/min. Group B: Total dose of levosimendan which would be given through intravenous route over 24 h was calculated and then divided into four equal parts and administered through inhalational route 6^th hourly over 24 h. Hemodynamic profile (pulse rate, mean arterial pressure, pulmonary artery systolic pressure [PASP], SVR) and RV function were assessed immediately after shifting, at 1, 8, 24, and 36 h after shifting to recovery.

Statistical Analysis Used:

Intragroup analysis was done using paired student t-test, and unpaired student t-test was used for analysis between two groups.

Results:

PASP and RV-fractional area change (RV-FAC) were comparable in the two groups at different time intervals. There was a significant reduction in PASP and significant improvement in RV-FAC with both intravenous and inhalational levosimendan. SVR was significantly decreased with intravenous levosimendan, but no significant decrease in SVR was observed with inhalational levosimendan.

Conclusions:

Inhaled levosimendan is a selective pulmonary vasodilator. It causes decrease in PAP and improvement in RV function, without having a significant effect on SVR.

Echocardiographic Correlation between Right Ventricular Function and Left Atrial Volume

Background

Few reports exist on the relationship of the left ventricular diastolic dysfunction (LVDD) with its most important features including enlargement of the left atrium and left ventricular hypertrophy (LVH), and with the right ventricular (RV) function.

Objective

To determine the correlation between the left atrial size and the RV function and dimensions in patients with and without LVDD and LVH.

Methods

Fifty patients were included, 25 (40% men) of them with LVDD, aged 67.1 ± 10.6 years (study group) and 25 without LVDD (52% men) aged 49.9 ± 16.3 years (control group). Patients underwent transthoracic echocardiography with evaluation of the left atrial size and volume (LAV), LVDD, LVH, and RV function and dimensions. P-values < 0.05 were considered statistically significant.

Results

LAV > 34 mL/m² and left atrial size > 40 mm were associated with lower absolute values of tricuspid annular plane systolic excursion (TAPSE) and RV lateral S' (p ≤ 0.001, Pearson's correlation coefficient -0.4 and -0.38, respectively) in the study group. Patients in the study group showed higher incidence of LVH (p = 0.02) and greater left atrial diameter (p = 0.03) compared with the control group. In addition, greater left atrial diameter (p = 0.02) and LAV (p = 0.01) values were found in patients with LVDD grade II compared with LVDD grade I.

Conclusions

The present study determined, for the first time, the correlation of left atrial enlargement with progressive RV dysfunction in patients with LVDD.

Influence of impaired right ventricular contractile reserve on exercise capacity in patients with precapillary pulmonary hypertension: A study with exercise stress echocardiography

OBJECTIVES

Right ventricular (RV) contractile reserve reflects the ability of RV to accommodate the increased afterload and may play an essential role in the evaluation of precapillary pulmonary hypertension (PH). This study aimed to assess RV contractile reserve based on exercise stress echocardiography (ESE) and to determine the echocardiographic determinants of exercise capacity in patients with precapillary PH.

METHODS

A total of 31 patients with precapillary PH and 15 age- and sex-matched healthy control subjects were prospectively recruited. All subjects underwent ESE to assess RV function at rest and under peak exercise. Changes in these parameters during exercise were calculated to quantify the RV contractile reserve. Patients with precapillary PH also underwent cardiopulmonary exercise test (CPET), and data pertaining to peak oxygen uptake (peak VO₂ ) and minute ventilation/carbon dioxide production (VE/VCO₂ ) were collected.

RESULTS

Right ventricular contractile reserve including change in tricuspid annular plane systolic excursion (∆TAPSE), change in RV fractional area change (∆RVFAC), and change in Doppler-derived tricuspid lateral annular peak systolic velocity (∆S') was significantly depressed in precapillary PH patients compared with control subjects (P < 0.05). Parameters of RV function and RV contractile reserve were markedly associated with maximal exercise capacity (P < 0.05). ∆RVFAC was an independent predictor of peak VO₂ (r²  = 0.601, P < 0.05).

CONCLUSIONS

Assessment of RV contractile reserve facilitates identification of subclinical dysfunction and evaluation of clinical status and severity of precapillary PH. ESE as a noninvasive method may provide a comprehensive clinical assessment and facilitate therapeutic decision-making for these patients.

The Sugen 5416/Hypoxia Mouse Model of Pulmonary Arterial Hypertension

Pulmonary hypertension is a rapidly progressive, life-threatening, and often fatal disease. Despite many new developments in pulmonary arterial hypertension (PAH) therapy, there is currently no cure for PAH, and new therapies are desperately needed. PAH pathobiology involves a remodeling process in pulmonary arteries that plays a critical role in elevating pulmonary arterial and right ventricle pressures. The discovery and development of new therapies requires animal models of PAH that mimic the human disease, including vascular remodeling.Here we review and describe a detailed protocol for creating an in vivo model of Sugen/Hypoxia-induced PAH in mice that is commonly used to assess the efficiency of new therapies in PAH. Severe pulmonary hypertension can be established in 1 month using this protocol. Additional protocols to evaluate the model by invasive pressure measurements and histology are provided.

Bi-ventricular finite element model of right ventricle overload in the healthy rat heart

BACKGROUND

The recognition of RV overpressure is critical to human life, as this may signify morbidity and mortality. Right ventricle (RV) dysfunction is understood to have an impact on the performance of the left ventricle (LV), but the mechanisms remain poorly understood. It is understood that ventricular compliance has the ability to affect cardiac performance. In this study, a bi-ventricular model of the rat heart was used in preference to other, single-ventricle models. Finite element analysis (FEA) of the bi-ventricular model provides important information on the function of the healthy heart.

METHODS

The passive myocardium was modelled as a nearly incompressible, hyperelastic, transversely isotropic material using finite element (FE) methods. Bi-ventricular geometries of healthy rat hearts reconstructed from magnetic resonance images were imported in Abaqus©. In simulating the normal passive filling of the rat heart, pressures of 4.8 kPa and 0.0098 kPa were applied to the inner walls of the LV and RV respectively. In addition, to simulate the overpressure of the RV, pressures of 2.4 kPa and 4.8 kPa were applied to the endocardial walls of the LV and RV respectively. As boundary conditions, the circumferential and longitudinal displacements at the base were set to zero. The radial displacements at the base were left free.

RESULTS

The results show that the average circumferential stress at the mid-wall in the overloaded model increased from 2.8 kPa to 18.2 kPa. The average longitudinal stress increased from 1.5 kPa to 9.7 kPa. Additionally, in the radial direction, the average stress increased from 0.1 kPa to 0.6 kPa in the mid-wall. The average circumferential strain was found to be 0.138 and 0.100 on the endocardium of the over pressured and healthy model respectively. The average circumferential stress at the epicardium, mid-wall and endocardium in the case of a normal heart is 10 times lower than in the overloaded heart model.

CONCLUSION

The finite analysis method is able to provide insights into the behaviour of the over pressured model (myocardium). In the overloaded model the high stresses and strains were observed on the septal wall. The bi-ventricular model was shown to provide useful information relating to the over pressured ventricle. The possible heart dysfunction may be attributable to high stress and strain in the over pressured heart.

The right ventricle: interaction with the pulmonary circulation

The primary role of the right ventricle (RV) is to deliver all the blood it receives per beat into the pulmonary circulation without causing right atrial pressure to rise. To the extent that it also does not impede left ventricular (LV) filling, cardiac output responsiveness to increased metabolic demand is optimized. Since cardiac output is a function of metabolic demand of the body, during stress and exercise states the flow to the RV can vary widely. Also, instantaneous venous return varies widely for a constant cardiac output as ventilatory efforts alter the dynamic pressure gradient for venous return. Normally, blood flow varies with minimal changes in pulmonary arterial pressure. Similarly, RV filling normally occurs with minimal increases in right atrial pressure. When pulmonary vascular reserve is compromised RV ejection may also be compromised, increasing right atrial pressure and limiting maximal cardiac output. Acute increases in RV outflow resistance, as may occur with acute pulmonary embolism, will cause acute RV dilation and, by ventricular interdependence, markedly decreased LV diastolic compliance, rapidly spiraling to acute cardiogenic shock and death. Treatments include reversing the causes of pulmonary hypertension and sustaining mean arterial pressure higher than pulmonary artery pressure to maximal RV coronary blood flow. Chronic pulmonary hypertension induces progressive RV hypertrophy to match RV contractility to the increased pulmonary arterial elastance. Once fully developed, RV hypertrophy is associated with a sustained increase in right atrial pressure, impaired LV filling, and decreased exercise tolerance. Treatment focuses on pharmacologic therapies to selectively reduce pulmonary vasomotor tone and diuretics to minimize excessive RV dilation. Owning to the irreversible nature of most forms of pulmonary hypertension, when the pulmonary arterial elastance greatly exceeds the adaptive increase in RV systolic elastance, due to RV dilation, progressive pulmonary vascular obliteration, or both, end stage cor pulmonale ensues. If associated with cardiogenic shock, it can effectively be treated only by artificial ventricular support or lung transplantation. Knowing how the RV adapts to these stresses, its sign posts, and treatment options will greatly improve the bedside clinician’s ability to diagnose and treat RV dysfunction.

2-Dimensional Strain Analysis of Regional Change in Right Ventricular Function after Treadmill Exercise

Background

Function of right ventricle (RV) influences on symptoms and prognosis in various diseases. However the regional RV function analyzed with 2-dimensional (2D) strain echocardiography before and just after treadmill test has not been evaluated. The aim of this study was to show the change of regional RV function just after treadmill exercise with strain analysis.

Methods

A total of thirty eight patients who visited hospital for hypertension, chest pain or dyspnea between January 2007 and December 2010 were retrospectively analyzed (men, 47.4%; mean age, 54.9 ± 7.2 years). Treadmill exercise test and pre and post echocardiography were performed. 2D strain echocardiography was analyzed off line in RV free wall and septum.

Results

Mean exercise duration was 737 ± 132 sec. Tissue velocity in lateral tricuspid annulus is significantly increased in post exercise (initial, 10.5 ± 2.4 cm/sec vs. post exercise, 12.2 ± 1.8 cm/sec, p = 0.006). Systolic strain of RV free wall apex and mid portion were significantly changed in post exercise stage (free wall apex, -18.2 ± 7.6% vs. -22.3 ± 5.8%, p = 0.010; free wall mid, -14.1 ± 6.7% vs. -22.6 ± 6.8%, p = 0.022).

Conclusion

2D strain imaging provides a precise tool to quantify regional RV function and reveals a characteristic regional pattern of RV after treadmill exercise.

Inhaled therapy for the management of perioperative pulmonary hypertension

Patients with pulmonary hypertension (PH) are at high risk for complications in the perioperative setting and often receive vasodilators to control elevated pulmonary artery pressure (PAP). Administration of vasodilators via inhalation is an effective strategy for reducing PAP while avoiding systemic side effects, chiefly hypotension. The prototypical inhaled pulmonary-specific vasodilator, nitric oxide (NO), has a proven track record but is expensive and cumbersome to implement. Alternatives to NO, including prostanoids (such as epoprostenol, iloprost, and treprostinil), NO-donating drugs (sodium nitroprusside, nitroglycerin, and nitrite), and phosphodiesterase inhibitors (milrinone, sildenafil) may be given via inhalation for the purpose of treating elevated PAP. This review will focus on the perioperative therapy of PH using inhaled vasodilators.

Right ventricular adaptation and failure in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an obstructive pulmonary vasculopathy, characterized by excess proliferation, apoptosis resistance, inflammation, fibrosis, and vasoconstriction. Although PAH therapies target some of these vascular abnormalities (primarily vasoconstriction), most do not directly benefit the right ventricle (RV). This is suboptimal because a patient's functional state and prognosis are largely determined by the success of the adaptation of the RV to the increased afterload. The RV initially hypertrophies but might ultimately decompensate, becoming dilated, hypokinetic, and fibrotic. A number of pathophysiologic abnormalities have been identified in the PAH RV, including: ischemia and hibernation (partially reflecting RV capillary rarefaction), autonomic activation (due to G protein receptor kinase 2-mediated downregulation and desensitization of β-adrenergic receptors), mitochondrial-metabolic abnormalities (notably increased uncoupled glycolysis and glutaminolysis), and fibrosis. Many RV abnormalities are detectable using molecular imaging and might serve as biomarkers. Some molecular pathways, such as those regulating angiogenesis, metabolism, and mitochondrial dynamics, are similarly deranged in the RV and pulmonary vasculature, offering the possibility of therapies that treat the RV and pulmonary circulation. An important paradigm in PAH is that the RV and pulmonary circulation constitute a unified cardiopulmonary unit. Clinical trials of PAH pharmacotherapies should assess both components of the cardiopulmonary unit.

The interface between monitoring and physiology at the bedside

Hemodynamic instability as a clinical state represents either a perfusion failure with clinical manifestations of circulatory shock or heart failure or 1 or more out-of-threshold hemodynamic monitoring values, which may not necessarily be pathologic. Different types of causes of circulatory shock require different types of treatment modalities, making these distinctions important. Diagnostic approaches or therapies based on data derived from hemodynamic monitoring assume that specific patterns of derangements reflect specific disease processes, which respond to appropriate interventions. Hemodynamic monitoring at the bedside improves patient outcomes when used to make treatment decisions at the right time for patients experiencing hemodynamic instability.

Vascular stiffening in pulmonary hypertension: cause or consequence? (2013 Grover Conference series)

Recent studies have indicated that systemic arterial stiffening is a precursor to hypertension and that hypertension, in turn, can perpetuate arterial stiffening. Pulmonary artery (PA) stiffening is also well documented to occur in pulmonary hypertension (PH), and there is evidence that pulmonary vascular stiffness (PVS) may be a better predictor of outcome than pulmonary vascular resistance (PVR). We have hypothesized that the decreased flow-damping function of elastic PAs in PH likely initiates and/or perpetuates dysfunction of pulmonary microvasculature. Recent studies have shown that large-vessel stiffening increases flow pulsatility in the distal pulmonary vasculature, leading to endothelial dysfunction within a proinflammatory, vasoconstricting, and profibrogenic environment. The intricate role of stiffening-stimulated high pulsatile flow in endothelial cell dysfunction includes stepwise molecular events underlying PA hypertrophy, inflammation, endothelial-mesenchymal transition, and fibrosis. In addition to contributing to microenvironmental alterations of the distal vasculature, disordered proximal-distal PA coupling likely also plays a role in increasing ventricular afterload, ultimately causing right ventricle (RV) dysfunction and death. Current therapeutic treatments do not provide a realistic approach to destiffening arteries and, thus, to potentially abrogating the effects of high pulsatile flow on the distal pulmonary vasculature or the increased work imposed by stiffening on the RV. Scrutinizing the effect of PA stiffening on high pulsatile flow-induced cellular and molecular changes, and vice versa, might lead to important new therapeutic options that abrogate PA remodeling and PH development. With a clear understanding that PA stiffening may contribute to the progression of PH to an irreversible state by contributing to chronic microvascular damage in lungs, future studies should be aimed first at defining the underlying mechanisms leading to PA stiffening and then at improved treatment approaches based on these findings.

Gambogic acid moderates cardiac responses to chronic hypoxia likely by acting on the proteasome and NF-κB pathway

Gambogic acid (GA) is the principal active ingredient of gamboges. GA was reported to exert anti-tumor and anti-inflammatory effects both in vitro and in vivo. Previously, we have shown that GA is a more tissue-specific proteasome inhibitor than bortezomib and it is less toxic to peripheral white blood cells compared to bortezomib. Ubiquitous proteasome inhibition was shown by some reports, but not by others, to prevent cardiac remodeling in response to pressure overload by blocking the NF-κB pathway; however, whether GA modulates the development of chronic hypoxia-induced right ventricular hypertrophy has not been investigated yet. Here we report that GA can significantly attenuate right ventricular hypertrophy induced by chronic hypoxia, reduce cardiac fibrosis, and remarkably block the reactivation of bona fide fetal genes in the cardiac tissue. Furthermore, we also investigated the potential molecular targets of GA on right ventricular hypertrophy. The results showed that GA could accumulate the IκB levels associated with decreased proteasomal activity, block the translocation of NF-κB from the cytoplasm to the nucleus, decrease NF-κB DNA-binding activity, and reduce IL-2 levels. In conclusion, GA is capable of preventing the development of chronic hypoxia-induced right ventricular hypertrophy. GA has great potential to be developed into an effective anti-hypertrophy agent.

Outcomes After Primary Transcatheter Therapy in Infants and Young Children With Severe Bilateral Peripheral Pulmonary Artery Stenosis

Background—

Angioplasty and stent implantation have become accepted therapies for isolated peripheral pulmonary stenosis, and have been shown to increase vessel diameter and reduce right ventricular (RV) pressure acutely in patients with pulmonary artery (PA) stenosis. The purpose of this study was to assess long-term outcomes after primary transcatheter therapy for peripheral pulmonary stenosis.

Methods and Results—

We studied 69 patients who underwent primary transcatheter intervention for severe isolated peripheral pulmonary stenosis at ≤5 years of age. Genetic/syndromic diagnoses included Williams syndrome (n=23), non-Williams familial arteriopathy (n=12), and Alagille syndrome (n=3). At the initial PA intervention, median RV:aortic pressure ratio decreased from 1.00 to 0.88 (median decrease, 0.18; P <0.001). Patients with a higher preintervention RV:aortic pressure ratio had a greater reduction ( P <0.001). During follow-up (median, 8.5 years), 10 patients died, 5 from complications of PA catheterization (all before 1998). Thirteen patients underwent surgical PA intervention, most within 1 year and along with repair of supravalvar aortic stenosis. Freedom from any PA reintervention was 38±6% at 1 year and 22±6% at 5 years. The median RV:aortic pressure ratio decreased from 1.0 at baseline to 0.53 at the most recent catheterization ( P <0.001), and 82% of patients with available clinical follow-up were asymptomatic.

Conclusions—

Transcatheter therapy for infants with severe peripheral pulmonary stenosis has become safer, regardless of genetic condition. Coupled with reintervention and surgical relief in selected cases, RV:aortic pressure ratios decrease substantially and most patients are asymptomatic at late follow-up.

Nicorandil prevents right ventricular remodeling by inhibiting apoptosis and lowering pressure overload in rats with pulmonary arterial hypertension

Background

Most of the deaths among patients with severe pulmonary arterial hypertension (PAH) are caused by progressive right ventricular (RV) pathological remodeling, dysfunction, and failure. Nicorandil can inhibit the development of PAH by reducing pulmonary artery pressure and RV hypertrophy. However, whether nicorandil can inhibit apoptosis in RV cardiomyocytes and prevent RV remodeling has been unclear.

Methodology/Principal Findings

RV remodeling was induced in rats by intraperitoneal injection of monocrotaline (MCT). RV systolic pressure (RVSP) was measured at the end of each week after MCT injection. Blood samples were drawn for brain natriuretic peptide (BNP) ELISA analysis. The hearts were excised for histopathological, ultrastructural, immunohistochemical, and Western blotting analyses. The MCT-injected rats exhibited greater mortality and less weight gain and showed significantly increased RVSP and RV hypertrophy during the second week. These worsened during the third week. MCT injection for three weeks caused pathological RV remodeling, characterized by hypertrophy, fibrosis, dysfunction, and RV mitochondrial impairment, as indicated by increased levels of apoptosis. Nicorandil improved survival, weight gain, and RV function, ameliorated RV pressure overload, and prevented maladaptive RV remodeling in PAH rats. Nicorandil also reduced the number of apoptotic cardiomyocytes, with a concomitant increase in Bcl-2/Bax ratio. 5-hydroxydecanoate (5-HD) reversed these beneficial effects of nicorandil in MCT-injected rats.

Conclusions/Significance

Nicorandil inhibits PAH-induced RV remodeling in rats not only by reducing RV pressure overload but also by inhibiting apoptosis in cardiomyocytes through the activation of mitochondrial ATP-sensitive K⁺ (mitoK_ATP) channels. The use of a mitoK_ATP channel opener such as nicorandil for PAH-associated RV remodeling and dysfunction may represent a new therapeutic strategy for the amelioration of RV remodeling during the early stages of PAH.

Surgical treatment of pulmonary hypertension: Lung transplantation

Pulmonary hypertension (PH) is a serious and progressive disorder that results in right ventricular dysfunction that lead to subsequent right heart failure and death. When untreated the median survival for these patients is 2.8 years. Over the past decade advances in disease specific medical therapy considerably changed the natural history. This is reflected in a threefold decrease in the number of patients undergoing lung transplantation for PH which used to be main stay of treatment. Despite the successful development of medical therapy lung transplant still remains the gold standard for patients who fail medical therapy. Referral for lung transplant is recommended when patients have a less than 2-3 years of predicted survival or in NYHA class III or IV. Both single and bilateral lung transplants have been successfully performed for PH but outcome analyses and survival comparisons generally favor a bilateral lung transplant.

Selective class I histone deacetylase inhibition suppresses hypoxia-induced cardiopulmonary remodeling through an antiproliferative mechanism

RATIONALE

Histone deacetylase (HDAC) inhibitors are efficacious in models of hypertension-induced left ventricular heart failure. The consequences of HDAC inhibition in the context of pulmonary hypertension with associated right ventricular cardiac remodeling are poorly understood.

OBJECTIVE

This study was performed to assess the utility of selective small-molecule inhibitors of class I HDACs in a preclinical model of pulmonary hypertension.

METHODS AND RESULTS

Rats were exposed to hypobaric hypoxia for 3 weeks in the absence or presence of a benzamide HDAC inhibitor, MGCD0103, which selectively inhibits class I HDACs 1, 2, and 3. The compound reduced pulmonary arterial pressure more dramatically than tadalafil, a standard-of-care therapy for human pulmonary hypertension that functions as a vasodilator. MGCD0103 improved pulmonary artery acceleration time and reduced systolic notching of the pulmonary artery flow envelope, which suggests a positive impact of the HDAC inhibitor on pulmonary vascular remodeling and stiffening. Similar results were obtained with an independent class I HDAC-selective inhibitor, MS-275. Reduced pulmonary arterial pressure in MGCD0103-treated animals was associated with blunted pulmonary arterial wall thickening because of suppression of smooth muscle cell proliferation. Right ventricular function was maintained in MGCD0103-treated animals. Although the class I HDAC inhibitor only modestly reduced right ventricular hypertrophy, it had multiple beneficial effects on the right ventricle, which included suppression of pathological gene expression, inhibition of proapoptotic caspase activity, and repression of proinflammatory protein expression.

CONCLUSIONS

By targeting distinct pathogenic mechanisms, isoform-selective HDAC inhibitors have potential as novel therapeutics for pulmonary hypertension that will complement vasodilator standards of care.

Acute pressure overload of the right ventricle. Comparison of two models of right-left shunt. Pulmonary artery to left atrium and right atrium to left atrium: experimental study

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