Benefit of prostaglandin infusion in severe heart failure: preliminary clinical experience of repetitive administration

Considerations in the Diagnosis and Management of Pulmonary Hypertension Associated With Left Heart Disease

Pulmonary hypertension associated with left heart disease (PH-LHD) remains the most common cause of pulmonary hypertension globally. Etiologies include heart failure with reduced and preserved ejection fraction and left-sided valvular heart diseases. Despite the increasing prevalence of PH-LHD, there remains a paucity of knowledge about the hemodynamic definition, diagnosis, treatment modalities, and prognosis among clinicians. Moreover, clinical trials have produced mixed results on the usefulness of pulmonary vasodilator therapies for PH-LHD. In this expert review, we have outlined the critical role of meticulous hemodynamic evaluation and provocative testing for cases of diagnostic uncertainty. Therapeutic strategies-pharmacologic, device-based, and surgical therapies used for managing PH-LHD-are also outlined. PH-LHD in advanced heart failure, and the role of mechanical circulatory support in PH-LHD is briefly explored. An in-depth understanding of PH-LHD by all clinicians is needed for improved recognition and outcomes among patients with PH-LHD.

Prostaglandin E1 attenuates AngII-induced cardiac hypertrophy via EP3 receptor activation and Netrin-1upregulation

AIMS

Pathological cardiac hypertrophy induced by activation of the renin-angiotensin-aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect.

METHODS AND RESULTS

Adult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E-prostanoid (EP) 3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1.

CONCLUSION

In conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1-MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy.

Pulmonary hypertension in patients with heart failure and preserved ejection fraction: differential diagnosis and management

The most common cause of pulmonary hypertension (PH) due to left heart disease (LHD) was previously rheumatic mitral valve disease. However, with the disappearance of rheumatic fever and an aging population, nonvalvular LHD is now the most common cause of group 2 PH in the developed world. In this review, we examine the challenge of investigating patients who have PH and heart failure with preserved ejection fraction (HF-pEF), where differentiating between pulmonary arterial hypertension (PAH) and PH-LHD can be difficult, and also discuss the entity of combined precapillary and postcapillary PH. Given the proven efficacy of targeted therapy for the treatment of PAH, there is increasing interest in whether these treatments may benefit selected patients with PH associated with HF-pEF, and we review current trial data.

Pathophysiology and potential treatments of pulmonary hypertension due to systolic left heart failure

Pulmonary hypertension (PH) due to left heart failure is becoming increasingly prevalent and is associated with poor outcome. The precise pathophysiological mechanisms behind PH due to left heart failure are, however, still unclear. In its early course, PH is caused by increased left ventricular filling pressures, without pulmonary vessel abnormalities. Conventional treatment for heart failure may partly reverse such passive PH by optimizing left ventricular function. However, if increased pulmonary pressures persist, endothelial damage, excessive vasoconstriction and structural changes in the pulmonary vasculature may occur. There is, at present, no recommended medical treatment for this active component of PH due to left heart failure. However, as the vascular changes in PH due to left heart failure may be similar to those in pulmonary arterial hypertension (PAH), a selected group of these patients may benefit from PAH treatment targeting the endothelin, nitric oxide or prostacyclin pathways. Such potent pulmonary vasodilators could, however, be detrimental in patients with left heart failure without pulmonary vascular pathology, as selective pulmonary vasodilatation may lead to further congestion in the pulmonary circuit, resulting in pulmonary oedema. The use of PAH therapies is therefore currently not recommended and would require the selection of suitable patients based on the underlying causes of the disease and careful monitoring of their progress. The present review focuses on the following: (i) the pathophysiology behind PH resulting from systolic left heart failure, and (ii) the current evidence for medical treatment of this condition, especially the role of PAH-targeted therapies in systolic left heart failure.

Prostaglandin E1 increases the blood flow rate of saphenous vein grafts in patients undergoing off-pump coronary artery bypass grafting

OBJECTIVE

To compare the effects of prostaglandin E1 (PGEl) versus placebo on blood flow rate in coronary artery bypass grafts.

DESIGN

A prospective, randomized, double-blinded study.

SETTING

A teaching hospital.

PARTICIPANTS

Forty-six patients with stable angina scheduled for isolated elective OPCAB were recruited and randomized into group PGE1 and group placebo.

INTERVENTION

Following randomization, the patients in the PGE1 group (Group PGE1, n = 23) received a continuous intravenous infusion of PGEl (10 ng/kg/min) after endotracheal intubation and the placebo group (Group placebo, n = 23) received the same volume of normal saline. The infusion administration was removed after leaving the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

The grafts' blood flow rate was measured with a transit time flowmeter at 10 minutes and 30 minutes after coronary artery grafting. The hemodynamic parameters, including mean arterial pressure (MAP), heart rate, and SvO2, VO2I, DO2I, ERO2 monitored by a pulmonary artery catheter, were recorded. The blood flow of the saphenous vein grafts was significantly higher in the PGE1 group than the placebo group at both 10 and 30 minutes after coronary artery grafting. At the 10-minute mark, the graft flow was 54.9 ± 31.4 mL/min versus 47.3 ± 24.6 mL/min in venous nonsequential grafts to the left coronary artery for group PGE1 and placebo (p = 0.000). Corresponding values at 30 minutes were 60.1 ± 27.8 mL/min versus 48.4 ± 26.3 mL/min (p = 0.002). In the venous non-sequential grafts to the right coronary artery, a tendency of blood flow also was found to be higher in the PGE1 group than in the placebo group at 10-minutes (52.7 ± 29.4 mL/min versus 49.3 ± 23.8 mL/min, p = 0.048) and the 30-minutes (58.6 ± 26.5 mL/min, 50.9 ± 25.9 mL/min, p = 0.037). The blood flow rate of the left internal mammary artery (LIMA) grafts in group PGE1 was higher than that in the placebo group but did not reach statistical significance. The VO2I, DO2I, and ERO2 in the 2 groups at the 2 time points did not reach statistical significance. The cardiac index (CI) in group PGE1 was higher than that of the placebo group at T3 and T4 (p = 0.035 and p = 0.012, respectively). The lactate (LAC) at the end of the operation (T2), 4 hours after the operation (T3), and 24 hours after operation (T4) in the placebo group were higher than that of group PGE1 (p = 0.023, p = 0.015, and p = 0.043, respectively). The oxygenation saturation of the mixed venous blood (SvO2) in the 2 groups was decreased but without significant difference.

CONCLUSION

PGE1 significantly increased the flow rate in anastomosed saphenous vein grafts, and its beneficial effects on hemodynamics and oxygen metabolism were observed.

Treatment for pulmonary hypertension of left heart disease

OPINION STATEMENT

Pulmonary hypertension (PH) secondary to left heart disease is a largely underestimated target of therapy. Except for a specific focus on PH consequences in patients with advanced heart failure (HF) receiving a left ventricular mechanical assist device or candidates for transplantation, prevention and treatment of initial subclinical forms of PH are not considered a priority in the management of this chronic disease population. Nonetheless, there is recent growing evidence supporting a clinical and prognostic role of PH in the elderly and in HF with preserved ejection fraction (pEF). Studies have defined PH-HFpEF as a new entity typically defining the evolving nature of disease. Although the prevalence of PH in these populations is not well-defined, the potential for effective pharmacological approaches that might impact the natural history of the disease starting from earlier stages is promising. However, it should be recognized that pharmacological studies performed to date with traditional pulmonary vasodilators in cohorts with HF and left-sided PH have not been positive, primarily because of concomitant systemic hypotension and hepatic side effects. This evidence along with the lack of studies specifically performed in the elderly and HFpEF often lead Guidelines to give neutral recommendations or even arbitrary assumptions. Recent availability of selective well-tolerated pulmonary vasodilators, such as phosphodiesterase type 5 (PDE5) inhibitors, however, seem to offer a solid background for treating left-sided PH at both early and later stages of the disease process.

Effect of lipo-prostaglandin E1 on cystatin C, β2-microglobulin, and estimated glomerular filtration rate in patients with decompensated heart failure and renal dysfunction: a single-center, nonrandomized controlled study

A nonrandomized controlled study was conducted to evaluate the effect of lipo-prostaglandin E1 (lipo-PGE1) on cystatin C (CysC), β2-microglobulin (B2MG), and estimated glomerular filtration rate (eGFR) in patients with decompensated heart failure (DHF) and renal dysfunction. A total of 286 enrolled patients with DHF and renal dysfunction were nonrandomly assigned a 7-day standard treatment without (n = 146) or with (n = 140) lipo-PGE1 intervention. According to the baseline eGFR, patients were further classified into mild, moderate, and severe renal dysfunction subgroups. By the end of study period, there was no evidence of an immense improvement in B2MG, CysC, and eGFR in response to standard treatment (all P > 0.05). On the contrary, a noticeable decrease of B2MG and CysC was observed in patients receiving lipo-PGE1 intervention, as well as an increase in eGFR (all P < 0.05). Moreover, lipo-PGE1 intervention led to greater changes in renal function variables from baseline than with standard management (all P < 0.05). Most important, the favorable renal protective effects of lipo-PGE1 were maintained in three subgroups. Lipo-PGE1 intervention brought a substantial renoprotective benefit to hospitalized DHF patients as compared with standard therapy, suggesting it might offer a promising therapeutic option for the management of renal dysfunction associated with DHF.

Prostaglandin E1 facilitates inotropic effects of 5-HT4 serotonin receptors and β-adrenoceptors in failing human heart

Prostaglandins have displayed both beneficial and detrimental effects in clinical studies in patients with severe heart failure. Prostaglandins are known to increase cardiac output, but the mechanism is not clarified. Here, we tested the hypothesis that prostaglandins can increase contractility in human heart by amplifying cAMP-dependent inotropic responses. Contractility was measured ex vivo in isolated left ventricular strips and phosphodiesterase (PDE) and adenylyl cyclase (AC) activity was measured in homogenates or membranes from failing human left ventricles. PGE(1) (1 µM) alone did not modify contractility, but given prior, amplified maximal serotonin (5-HT)-evoked (10 µM) contractile responses mediated by 5-HT(4) receptors several fold (24 ± 7 % with PGE(1) vs. 3 ± 2 % above basal with 5-HT alone). The 5-HT(4)-mediated inotropic response was amplified by the PDE3 inhibitor cilostamide and further amplified in combination with PGE(1) (26 ± 6 vs. 56 ± 12 % above basal). PGE(1) reduced the time to reach 90 % of both the maximal 5-HT- and isoproterenol-evoked inotropic response compared to 5-HT or isoproterenol alone. PGE(1) did not modify PDE activity in the homogenate, either alone or when given simultaneously with PDE3 and/or PDE4 inhibitors. Neither 5-HT- nor isoproterenol-stimulated AC activity was significantly amplified by PGE(1). Sensitivity of ventricular strips to Ca(2+) was not enhanced in the presence of PGE(1). Our results show that PGE(1) can enhance cAMP-mediated responses in failing human left ventricle, through a mechanism independent of PDE inhibition, amplification of AC activity or increasing sensitivity to calcium. This effect of PGE(1) possibly contributes to the increase of cardiac output, independent of decreased afterload, observed after prostaglandin administration in humans.

Prostanoid-mediated inotropic responses are attenuated in failing human and rat ventricular myocardium

Prostanoid-modulatory approaches in heart failure patients have displayed effects which may seem to be mutually incompatible. Both treatment with prostanoids and inhibition of prostanoid synthesis have resulted in increased mortality in heart failure patients. Currently, it is unknown if prostanoids mediate contractile effects in failing human heart and if this can explain some of the clinical effects seen after prostanoid modulatory treatments. Therefore, the objectives of this study were to determine if prostanoids could elicit direct inotropic responses in human ventricle, and if so to determine if they are modified in failing ventricle. Contractile force was measured in left ventricular strips from non-failing or failing human and rat hearts. The ratio of phosphorylated to non-phosphorylated myosin light chain 2 (MLC-2) was measured by Western blotting in myocardial strips, and the levels of prostanoid FP receptor mRNA and protein were measured in rat by real-time RT-PCR and receptor binding assays. In non-failing human hearts, prostanoids evoked a positive inotropic effect and an increase of MLC-2 phosphorylation which was absent in failing human hearts. In failing rat heart, the prostanoid FP receptor-mediated inotropic response and prostanoid FP receptor-density was reduced by ~40-50% compared to non-failing rat heart. Prostanoids mediate a sustained positive inotropic response in non-failing heart, which appears to be down regulated in failing heart. The pathophysiological significance of changes in prostanoid-mediated inotropic support in the failing heart remains to be determined.

Pulmonary hypertension with left-sided heart disease

Pulmonary hypertension (PH) with left-sided heart disease is defined, according to the latest Venice classification, as a Group 2 PH, which includes left-sided ventricular or atrial disease, and left-sided valvular diseases. These conditions are all associated with increased left ventricular filling pressure. Although PH with left-sided heart disease is a common entity, and long-term follow-up trials have provided firm recognition that development of left-sided PH carries a poor outcome, available data on incidence, pathophysiology, and therapy are sparse. Mitral stenosis was reported as the most frequent cause of PH several decades ago, but PH with left-sided heart disease is now usually caused by systemic hypertension and ischemic heart disease. In patients with these conditions, PH develops as a consequence of impaired left ventricular relaxation and distensibility. Chronic sustained elevation of cardiogenic blood pressure in pulmonary capillaries leads to a cascade of untoward retrograde anatomical and functional effects that represent specific targets for therapeutic intervention. The pathophysiological and clinical importance of the hemodynamic consequences of left-sided heart disease, starting with lung capillary injury and leading to right ventricular overload and failure, are discussed in this Review, focusing on PH as an evolving contributor to heart failure that may be amenable to novel interventions.