Pulmonary hypertension due to left heart disease

The future of group 2 pulmonary hypertension: Exploring clinical trials and therapeutic targets

Pulmonary hypertension due to left heart disease (PH-LHD) or group 2 PH is the most common and lethal form of PH, occurring secondary to left ventricular systolic or diastolic heart failure (HF), left-sided valvular diseases, and congenital abnormalities. It is subdivided into isolated postcapillary PH (IpcPH) and combined pre- and post-capillary PH (CpcPH), with the latter sharing many similarities with group 1 PH. CpcPH is associated with worse outcomes and increased morbidity and mortality when compared to IpcPH. Although IpcPH can be improved by treatment of the underlying LHD, CpcPH is an incurable disease for which no specific treatment exists, likely due to the lack of understanding of its underlying mechanisms. Furthermore, drugs approved for PAH are not recommended for group 2 PH, as they are either ineffective or even deleterious. With this major unmet medical need, a better understanding of mechanisms and the identification of effective treatment strategies for this deadly condition are urgently needed. This review presents relevant background of the molecular mechanisms underlying PH-LHD that could translate into innovative therapeutic targets and explores novel targets currently being evaluated in clinical trials.

Cardiac amyloidosis presenting as pulmonary arterial hypertension: A case report

BACKGROUND

Pulmonary hypertension is a rare cardiopulmonary disease, with an insidious onset that usually worsens rapidly. Amyloid light chain (AL) amyloidosis is a rare systemic disease caused by extracellular deposition of pathologic, insoluble, and proteinaceous fibrils in organs and tissues; however, it is difficult to diagnose given its varied and nonspecific symptoms. To date, rare cases of amyloidosis with pulmonary hypertension have been reported. Of note, the optimal treatments for cardiac amyloidosis complicated with pulmonary hypertension remain unclear.

CASE SUMMARY

We report a case of a 51-year-old woman who presented with progressively worsening dyspnea. Transthoracic echocardiography indicated severe pulmonary hypertension. Twenty-seven months after first admission, the patient returned with symptoms of progressive heart failure. A myocardial tissue sample stained with Congo red was positive, and the patient was ultimately diagnosed with AL amyloidosis with cardiac involvement.

CONCLUSION

Although pulmonary hypertension may be idiopathic, it is frequently associated with other conditions. In rare cases, pulmonary hypertension can be a complication of AL amyloidosis, which should be seriously considered in any adult presenting with nonspecific signs or symptoms of cardiac distress.

Relationships between Pulmonary Hypertension Risk, Clinical Profiles, and Outcomes in Dilated Cardiomyopathy

Pulmonary hypertension (PH) in patients with heart failure (HF) contributes to a poorer prognosis. However, in those with dilated cardiomyopathy (DCM), the true prevalence and role of PH is unclear. Therefore, this study aimed to analyze the profile of DCM patients at various levels of PH risk, determined via echocardiography, and its impact on outcomes. The 502 DCM in- and out-patient records were retrospectively analyzed. Information on patient status was gathered after 45.9 ± 31.3 months. Patients were divided into 3 PH-risk groups based on results from echocardiography measurements: low (L, n = 239, 47.6%), intermediate (I, n = 153, 30.5%), and high (H, n = 110, 21.9%). Symptom duration, atrial fibrillation, ventricular tachyarrhythmia, ejection fraction, right atrial area, and moderate or severe mitral regurgitation were found to be independently associated with PH risk. During the follow-up period, 83 (16.5%) DCM patients died: 29 (12.1%) in L, 31 (20.3%) in I, and 23 (20.9%) in H. L-patients had a significantly lower risk of all-cause death (L to H: HR 0.55 (95%CI 0.32–0.98), p = 0.01), while no differences in prognosis were found between I and H. In conclusion, over one in five DCM patients had a high PH risk, and low PH risk was associated with better prognoses.

Comprehensive network analysis to identify the molecular pathogenesis of pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PAH) is a chronic progressive disease that may lead to right heart failure and eventually death. At present, great progress had been achieved in the treatment of pulmonary hypertension. However, pulmonary hypertension cannot be fundamentally cured, and its pathogenesis is still unclear.

METHODS

A multifactor-driven dysfunction module of pulmonary hypertension has been constructed in order to explore its potential pathogenesis. We performed differential expression analysis, coexpression analysis, enrichment analysis and hypergeometric test to calculate the potential regulatory effects of multiple factors on the module.

RESULTS

Four modules and corresponding hub genes were identified. In addition, we also obtained a series of ncRNA (MALAT1 and miR-17-5p) and transcription factor (HIF1A). Network analysis revealed that MALAT1, NFKB1 and RELA targeting IL1B of module 4 and IL6 of module 1 to participate in the occurrence and development of pulmonary hypertension through Toll-like receptor signaling pathway.

CONCLUSIONS

It is necessary to identify disease-related disorders by integrating multiple regulatory factors. The regulatory network may play an important role in PAH. The results not only provided new methods and ideas for follow-up research, but also helps researchers to have a deeper understanding of potential pathogenesis for PAH.

Prolargin and matrix metalloproteinase-2 in heart failure after heart transplantation and their association with haemodynamics

Aims

Remodelling of the extracellular matrix (ECM) is a key mechanism involved in the development and progression of heart failure (HF) but also functional in associated pulmonary hypertension (PH). Our aim was to identify plasma ECM proteins associated to end‐stage HF and secondary PH in relation to haemodynamics, before and after heart transplantation (HT).

Methods and results

Twenty ECM plasma proteins were analysed with proximity extension assay in 20 controls and 26 HF patients pre‐HT and 1 year post‐HT. Right heart catherization haemodynamics were assessed in the patients during the preoperative evaluation and at the 1 year follow‐up post‐HT. Plasma levels of prolargin and matrix metalloproteinase‐2 (MMP‐2) were elevated (P < 0.0001) in HF patients compared with controls and decreased (P < 0.0001) post‐HT towards controls' levels. The decrease in prolargin post‐HT correlated with improved mean right atrial pressure (r_s = 0.63; P = 0.00091), stroke volume index (r_s = −0.73; P < 0.0001), cardiac index (r_s = −0.64; P = 0.00057), left ventricular stroke work index (r_s = −0.49; P = 0.015), and N‐terminal pro brain natriuretic peptide (r_s = 0.7; P < 0.0001). The decrease in MMP‐2 post‐HT correlated with improved mean pulmonary artery pressure (r_s = 0.58; P = 0.0025), mean right atrial pressure (r_s = 0.56; P = 0.0046), pulmonary artery wedge pressure (r_s = 0.48; P = 0.016), and N‐terminal pro brain natriuretic peptide (r_s = 0.56; P = 0.0029).

Conclusions

The normalization pattern in HF patients of plasma prolargin and MMP‐2 post‐HT towards controls' levels and their associations with improved haemodynamics indicate that prolargin and MMP‐2 may reflect, in part, the aberrant ECM remodelling involved in the pathophysiology of HF and associated PH. Their potential clinical use as biomarkers or targets for future therapy in HF and related PH remains to be investigated.

Relationship between pulmonary hypertension and outcomes among patients with heart failure with reduced ejection fraction

Objectives: To identify predictors of pulmonary hypertension (PHT) and the predictive value of PHT for rehospitalization among patients with heart failure with reduced ejection fraction (HFrEF). Methods: A retrospective study of 351 hospitalized patients with heart failure (HF). Patients 18 years and above with HFrEF secondary to non-ischemic cardiomyopathy were reviewed. Patients with coronary artery disease, preserved ejection fraction and other secondary causes of PHT apart from HF were excluded. PHT as a predictor of 30-day and six-month re-admission was assessed as well as important possible predictors of PHT. Cox regression analysis, multiple linear regression as well as other statistical tools were employed as deemed appropriate. Results: Thirty-seven (37) and 99 patients were re-hospitalized within 30 days and 6 months after discharge for decompensated HF, respectively. After Cox regression analysis, higher hemoglobin reduced the odds of rehospitalization for decompensated HF (p = 0.015) within 30 days after discharge while higher pulmonary artery systolic pressure (PASP) (p = 0.002) and blood urea nitrogen (BUN) (p = 0.041) increased the odds of rehospitalization within 6 months of discharge. The predictors of the PHT among patients with HFrEF after multiple linear regression were low BMI (p = 0.027), increasing age (p = 0.006) and increased left atrial diameter (LAD) on echocardiography (p = 0.0001). Conclusion: Patients with HFrEF have a high predisposition to developing PHT if at admission, they have low BMI, dilated left atrium or are older. Patients with one or more of these attributes may need more intensive therapy to reduce the risk of developing PHT and in turn reduce readmission rates.

Distinct plasma gradients of microRNA-204 in the pulmonary circulation of patients suffering from WHO Groups I and II pulmonary hypertension

Pulmonary hypertension (PH), a heterogeneous vascular disease, consists of subtypes with overlapping clinical phenotypes. MicroRNAs, small non-coding RNAs that negatively regulate gene expression, have emerged as regulators of PH pathogenesis. The muscle-specific micro RNA (miR)-204 is known to be depleted in diseased pulmonary artery smooth muscle cells (PASMCs), furthering proliferation and promoting PH. Alterations of circulating plasma miR-204 across the trans-pulmonary vascular bed might provide mechanistic insights into the observed intracellular depletion and may help distinguish PH subtypes. MiR-204 levels were quantified at sequential pulmonary vasculature sites in 91 patients with World Health Organization (WHO) Group I pulmonary arterial hypertension (PAH) (n = 47), Group II PH (n = 22), or no PH (n = 22). Blood from the right atrium/superior vena cava, pulmonary artery, and pulmonary capillary wedge was collected. Peripheral blood mononuclear cells (PBMCs) were isolated (n = 5/group). Excretion of miR-204 by PAH-PASMCs was also quantified in vitro. In Group I patients only, miR-204 concentration increased sequentially along the pulmonary vasculature (log fold-change slope = 0.22 [95% CI = 0.06–0.37], P = 0.008). PBMCs revealed insignificant miR-204 variations among PH groups (P = 0.12). Cultured PAH-PAMSCs displayed a decrease of intracellular miR-204 (P = 0.0004), and a converse increase of extracellular miR-204 (P = 0.0018) versus control. The stepwise elevation of circulating miR-204 across the pulmonary vasculature in Group I, but not Group II, PH indicates differences in muscle-specific pathobiology between subtypes. Considering the known importance of miR-204 in PH, these findings may suggest pathologic excretion of miR-204 in Group I PAH by PASMCs, thereby accounting for decreased intracellular miR-204 concentration.