Pulmonary Hypertension with Valvular Heart Disease: When to Treat the Valve Disease and When to Treat the Pulmonary Hypertension

Clinical-imaging-pathological correlation in pulmonary hypertension associated with left heart disease

Pulmonary hypertension (PH) is highly prevalent in patients with left heart disease (LHD) and negatively impacts prognosis. The most common causes of PH associated with LHD (PH-LHD) are left heart failure and valvular heart disease. In LHD, passive backward transmission of increased left-sided filling pressures leads to isolated post-capillary PH. Additional pulmonary vasoconstriction and remodelling lead to a higher vascular load and combined pre- and post-capillary PH. The increased afterload leads to right ventricular dysfunction and failure. Multimodality imaging of the heart plays a central role in the diagnostic work-up and follow-up of patients with PH-LHD. Echocardiography provides information about the estimated pulmonary artery pressure, morphology and function of the left and right side of the heart, and valvular abnormalities. Cardiac magnetic resonance imaging is the gold standard for volumetric measurements and provides myocardial tissue characterisation. Computed tomography of the thorax may show general features of PH and/or LHD and is helpful in excluding other PH causes. Histopathology reveals a spectrum of pre- and post-capillary vasculopathy, including intimal fibrosis, media smooth muscle cell hyperplasia, adventitial fibrosis and capillary congestion. In this paper, we provide an overview of clinical, imaging and histopathological findings in PH-LHD based on three clinical cases.

Pulmonary Hypertension in Left Ventricular Valvular Diseases: A Comprehensive Review on Pathophysiology and Prognostic Value

Left ventricular (LV) valvular diseases, make up one of the most common etiologies for pulmonary hypertension (PH), and it is not well understood how and at which degree it affects prognosis. The aim of the present study was a comprehensive review of the pathophysiologic mechanism of PH in patients with LV valvular diseases and the prognostic value of baseline and post-intervention PH in patients undergoing interventional treatment. The pathophysiology of PH in patients with LV valvular diseases involves gradual elevation of left ventricular filling pressure and left atrial pressure, which are passively transmitted to the pulmonary circulation and raise pulmonary artery systolic pressure (PASP). A long-lasting exposure to elevated PASP progressively leads to initially functional and thereafter irreversible structural changes in the pulmonary vasculature, leading up to high pulmonary vascular resistance. Surgical treatment of severe LV valvular diseases is highly effective in patients without resting PH or those with exercise-induced PH (EIPH) before intervention. In the case of pre-operative PH, successful interventional therapy decreases PASP, but the post-operative cardiac and all-cause mortality remain higher compared to patients without pre-operative PH. Hence, it is of paramount importance to detect patients with severe LV valvulopathies before the development of PH, since they will get greater benefits from early intervention.

Predictors of Outcome in Patients with Pulmonary Hypertension Undergoing Mitral and Tricuspid Valve Surgery

Background and Objectives: Pulmonary hypertension (PH) secondary to left-sided valvular heart disease is associated with poor cardiac surgical outcome compared with patients without PH. Our objective was to investigate the prognostic factors of surgical outcome in patients with PH undergoing mitral valve (MV) and tricuspid valve (TV) surgery, in order to risk stratify their management. Materials and Methods: This is a retrospective observational study on patients with PH who underwent MV and TV surgery from 2011 to 2019. The primary outcome was all-cause mortality. The secondary outcomes were post-op respiratory and renal complications, length of intensive care unit stay and length of hospital stay. Results: Seventy-six patients were included in this study. The all-cause mortality was 13% (n = 10), with mean survival of 92.6 months. Among the patients, 9.2% (n = 7) had post-op renal failure requiring renal replacement therapy and 6.6% (n = 5) had post-op respiratory failure requiring intubation. Univariate analysis demonstrated that pre-operative left ventricular ejection fraction (LVEF), peak systolic tissue velocity at the tricuspid annulus (S') and etiology of MV disease were associated with respiratory and renal failure. Tricuspid annular plane systolic excursion (TAPSE) was associated with respiratory failure only. S', type of operation, LVEF, urgency of surgery, and etiology of MV disease were found to be predictive of mortality. After excluding redo mitral surgery, all statistically significant findings remain unchanged, with the addition of right ventricular (RV) size being associated with respiratory failure. In the subgroup analysis of routine cases (n = 56), patients with primary mitral regurgitation who underwent mitral valve repair had better survival outcome. Conclusions: Urgency of surgery, etiology of MV disease, type of operation (replacement or repair), S' and pre-op LVEF are prognostic indicators in this small cohort of patients with PH undergoing MV and TV surgery. A larger prospective study is warranted to validate our findings.

Overexpression of Programmed Cell Death 1 Prevents Doxorubicin-Induced Apoptosis Through Autophagy Induction in H9c2 Cardiomyocytes

Doxorubicin (DOX) is a potent chemotherapeutic agent; however, it causes severe heart injury via apoptosis induction in many patients. DOX-induced cardiotoxicity is attenuated by activated autophagy in the heart. We previously found that programmed cell death 1 (Pdcd1), an immune checkpoint receptor, inhibits DOX-induced cardiomyocyte apoptosis. In this study, we investigated whether autophagy contributes to the protective role of Pdcd1 against DOX-induced cardiomyocyte apoptosis. We also examined the role of Pdcd1 in DOX-induced apoptosis in cancer cells. Rat cardiomyocyte cell line H9c2 and human cancer cell lines K562 and MCF-7 were transfected with Pdcd1-encoding plasmid DNA to establish Pdcd1-overexpressing cells. Apoptosis and autophagy were determined using a luciferase assay. In H9c2 cells, DOX-induced apoptosis and viability reduction occurred through caspase activation. In particular, Pdcd1 overexpression activated the autophagy pathway through the inhibition of the mammalian target of rapamycin, a major negative regulator of autophagy. Moreover, it prevented DOX-induced cardiomyocyte apoptosis; a similar cardioprotection was observed when normal H9c2 cells (without Pdcd1 overexpression) were treated with rapamycin, an autophagy inducer, before the DOX treatment. Conversely, in cancer cells, Pdcd1 overexpression increased both basal and DOX-induced apoptosis. The role of Pdcd1 in DOX-induced apoptosis in cardiomyocytes and cancer cells was opposing. Pdcd1 signaling prevented DOX-induced apoptosis in cardiomyocytes, through autophagy induction; it enhanced DOX-induced apoptosis in cancer cells. Therefore, Pdcd1 could be a critical molecule for more effective and safer DOX chemotherapy.

Circulating sLR11 levels predict severity of pulmonary hypertension due to left heart disease

BACKGROUND

Heart failure is a severe condition often involving pulmonary hypertension (PH). Soluble low-density lipoprotein receptor with 11 ligand-binding repeats (sLR11) has been associated with pulmonary artery hypertension. We examined whether sLR11 correlates with PH in left heart disease and can be used as a predictive marker.

METHOD

We retrospectively analyzed patients with severe mitral regurgitation who underwent right heart catheterization before surgery for valve replacement or valvuloplasty from November 2005 to October 2012 at Juntendo University. We measured sLR11 levels before right heart catheterization and analyzed correlations with pulmonary hemodynamics. We compared prognoses between a group with normal sLR11 (≤9.4 ng/ml) and a group with high sLR11 (>9.4 ng/ml). Follow-up was continued for 5 years, with end points of hospitalization due to HF and death due to cardiovascular disease.

RESULTS

Among 34 patients who met the inclusion criteria, sLR11 correlated with mean pulmonary artery pressure (r = 0.54, p<0.001), transpulmonary pressure gradient (r = 0.42, p = 0.012), pulmonary vascular resistance (r = 0.36, p<0.05), and log brain natriuretic peptide (BNP). However, logBNP did not correlate with pulmonary vascular resistance (p = 0.6). Levels of sLR11 were significantly higher in the 10 patients with PH (14.4±4.3 ng/ml) than in patients without PH (9.9±3.9 ng/ml; p = 0.002). At 5 years, the event rate was higher in the high-sLR11 group than in the normal-sLR11 group. The high-sLR11 group showed 5 hospitalizations due to HF (25.0%) and 2 deaths (10.0%), whereas the normal-sLR11 group showed no hospitalizations or deaths. Analyses using receiver operating characteristic curves showed a higher area under the concentration-time curve (AUC) for sLR11 level (AUC = 0.85; 95% confidence interval (CI) = 0.72-0.98) than for BNP (AUC = 0.80, 95%CI = 0.62-0.99) in the diagnosis of PH in left heart disease.

CONCLUSIONS

Concentration of sLR11 is associated with severity of PH and offers a strong predictor of severe mitral regurgitation in patients after surgery.

SOX17 Loss-of-Function Mutation Underlying Familial Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) refers to a rare, progressive disorder that is characterized by occlusive pulmonary vascular remodeling, resulting in increased pulmonary arterial pressure, right-sided heart failure, and eventual death. Emerging evidence from genetic investigations of pediatric-onset PAH highlights the strong genetic basis underpinning PAH, and deleterious variants in multiple genes have been found to cause PAH. Nevertheless, PAH is of substantial genetic heterogeneity, and the genetic defects underlying PAH in the overwhelming majority of cases remain elusive. In this investigation, a consanguineous family suffering from PAH transmitted as an autosomal-dominant trait was identified. Through whole-exome sequencing and bioinformatic analyses as well as Sanger sequencing analyses of the PAH family, a novel heterozygous SOX17 mutation, NM_022454.4: c.379C>T; p. (Gln127*), was found to co-segregate with the disease in the family, with complete penetrance. The nonsense mutation was neither observed in 612 unrelated healthy volunteers nor retrieved in the population genetic databases encompassing the Genome Aggregation Database, the Exome Aggregation Consortium database, and the Single Nucleotide Polymorphism database. Biological analyses using a dual-luciferase reporter assay system revealed that the Gln127*-mutant SOX17 protein lost the ability to transcriptionally activate its target gene NOTCH1. Moreover, the Gln127*-mutant SOX17 protein exhibited no inhibitory effect on the function of CTNNB1-encode β-catenin, which is a key player in vascular morphogenesis. This research firstly links SOX17 loss-of-function mutation to familial PAH, which provides novel insight into the molecular pathogenesis of PAH, suggesting potential implications for genetic and prognostic risk evaluation as well as personalized prophylaxis of the family members affected with PAH.

Efficacy of Beraprost Sodium Combined with Sildenafil and Its Effects on Vascular Endothelial Function and Inflammation in Patients Experiencing Left Heart Failure Complicated with Pulmonary Arterial Hypertension

Background

To explore the efficacy of beraprost sodium combined with sildenafil and its effects on the vascular endothelial function and inflammation in left heart failure patients complicated with pulmonary arterial hypertension.

Material/Methods

A total of 80 patients with left heart failure complicated with pulmonary arterial hypertension was enrolled as the subjects of this study and assigned into an observation group (n=40) and a control group (n=40) using a random number table. The changes in pulmonary arterial hypertension-associated indicators at 3 months after treatment and the alterations in the levels of cardiac function-associated biochemical indicator brain natriuretic peptide (BNP), inflammatory factor tumor necrosis factor alpha (TNF-α), and mean pulmonary arterial pressure during treatment were compared between the 2 groups.

Results

At 3 months after treatment, the pulmonary arterial hypertension-associated indicators human urotensin II and calcitonin gene-related peptide in the observation group were lower and higher, respectively, than those in control group. Moreover, the observation group had significantly lower BNP and TNF-α levels and mean pulmonary arterial pressure than the control group. After intervention, the echocardiographic parameters left ventricular ejection fraction (LVEF), cardiac output (CO), and stroke volume (SV) in both groups were significantly higher than those before intervention, and the observation group had significantly higher LVEF, SV, and CO than the control group after intervention.

Conclusions

Beraprost sodium combined with sildenafil for left heart failure complicated with pulmonary arterial hypertension can effectively improve pulmonary arterial hypertension, alleviate left heart failure, and reduce inflammatory responses, thereby achieving better clinical efficacy in patients.

MiR-18a-5p contributes to enhanced proliferation and migration of PASMCs via targeting Notch2 in pulmonary arterial hypertension

AIM

This study is undertaken to investigate the role and molecular mechanisms of miR-18a-5p in regulating pulmonary arterial hypertension (PAH) pathogenesis.

METHODS

Gene expression and protein levels were determined by qRT-PCR and western blot, respectively; Cell counting kti-8 and Transwell migration assays were used to determine the biological functions of miR-18a-5p in pulmonary arterial smooth muscle cells (PASMCs); bioinformatics analysis, luciferase reporter assays were used to elucidate the mechanisms of miR-18a-5p.

RESULTS

MiR-18a-5p was up-regulated in the clinical samples from PAH patients. PASMCs treated with hypoxia exhibited enhanced proliferative ability and upregulated miR-18a-5p expression. Knockdown of miR-18a-5p attenuated hypoxia-induced hyper-proliferation and enhanced migratory potential of PASMCs; while miR-18a-5p overexpression promoted PASMC proliferation and migration. Further mechanistic studies showed that Notch2 was a direct target of miR-18a-5p and was repressed by miR-18a-5p overexpression. The rescue studies indicated that Notch2 overexpression counteracted the enhanced proliferation and migration induced by miR-18a-5p mimics in PASMCs. Similarly, Notch2 overexpression also block the effects caused by hypoxia in PASMCs. Moreover, Notch2 expression was down-regulated in the PAH patients and was negatively correlated with miR-18a-5p expression. In vivo animal studies further revealed the up-regulation of miR-18a-5p and the down-regulation of Notch2 in the PAH rats.

CONCLUSIONS

Collectively, this study identified the up-regulated miR-18a-5p in the PAH patients; our data suggest that miR-18a-5p contributes to the enhanced proliferation and migration of PASMCs via repressing Notch2 expression.