Inhaled Prostacyclin on Exercise Echocardiographic Cardiac Function in Preserved Ejection Fraction Heart Failure

Novel insights into the pathobiology of pulmonary hypertension in heart failure with preserved ejection fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common cause of pulmonary hypertension (PH) worldwide and is strongly associated with adverse clinical outcomes. The American Heart Association recently highlighted a call to action regarding the distinct lack of evidence-based treatments for PH due to poorly understood pathophysiology of PH attributable to HFpEF (PH-HFpEF). Prior studies have described cardiophysiological mechanisms to explain the development of isolated postcapillary PH (ipc-PH); however, the consequent increase in pulmonary vascular (PV) resistance (PVR) may lead to the less understood and more fatal combined pre- and postcapillary PH (cpc-PH). Metabolic disease and inflammatory dysregulation have been suggested to predispose PH, yet the molecular mechanisms are unknown. Although PH-HFpEF has been studied to partly share vasoactive neurohormonal mediators with primary pulmonary arterial hypertension (PAH), clinical trials that have targeted these pathways have been unsuccessful. The increased mortality of patients with PH-HFpEF necessitates further study into viable mechanistic targets involved in disease progression. We aim to summarize the current pathophysiological and clinical understanding of PH-HFpEF, highlight the role of known molecular mechanisms in the progression of PV disease, and introduce a novel concept that lipid metabolism may be attenuating and propagating PH-HFpEF.NEW & NOTEWORTHY Our review addresses pulmonary hypertension (PH) attributable to heart failure (HF) with preserved ejection fraction (HFpEF; PH-HFpEF). Current knowledge gaps in PH-HFpEF pathophysiology have led to a lack of therapeutic targets. Thus, we address identified knowledge gaps in a comprehensive review, focusing on current clinical epidemiology, known pathophysiology, and previously studied molecular mechanisms. We also introduce a comprehensive review of polyunsaturated fatty acid (PUFA) lipid inflammatory mediators in PH-HFpEF.

Inhaled iloprost in off-pump coronary artery bypass surgery: a randomized controlled trial

PURPOSE

Mechanical cardiac constraint during off-pump coronary artery bypass surgery (OPCAB) causes right ventricle (RV) compression and increased pulmonary artery pressure (PAP), which may further compromise RV dysfunction. We aimed to assess the effect of inhaled iloprost, a potent selective pulmonary vasodilator, on the cardiac index (CI) during mechanical constraint. The secondary aim was to determine the resultant changes in the hemodynamic and respiratory parameters.

METHODS

A total of 100 adult patients with three-vessel coronary artery disease who had known risk factors for hemodynamic instability (congestive heart failure, mean PAP ≥ 25 mm Hg, RV systolic pressure ≥ 50 mm Hg on preoperative echocardiography, left ventricular ejection fraction < 50%, myocardial infarction within one month of surgery, redo surgery, and left main disease) were enrolled in a randomized controlled trial. The patients were randomly allocated to the control or iloprost groups at a 1:1 ratio, in which saline and iloprost (20 μg) were inhaled for 15 min after internal mammary artery harvesting, respectively. Cardiac index was measured by pulmonary artery catheterization.

RESULTS

There were no significant intergroup differences in CI during grafting (P = 0.36). The mean PAP had a significant group-time interaction (P = 0.04) and was significantly lower in the iloprost group at circumflex grafting (mean [standard deviation], 26 [3] mm Hg vs 24 [3] mm Hg; P = 0.01). The remaining hemodynamic parameters were similar between the groups.

CONCLUSION

Inhaled iloprost showed a neutral effect on hemodynamic parameters, including the CI and pulmonary vascular resistance index, during OPCAB.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04598191); first submitted 12 October 2020.

A non-invasive nomogram for predicting heart failure with preserved ejection fraction in taiwanese outpatients with unexplained dyspnea and fatigue

BACKGROUND

While Reddy proposed the H2FPEF diagnostic algorithm to aid in diagnosing heart failure with preserved ejection fraction (HFpEF), certain parameters like age and obesity are not suitable for Asian population, especially given the increasing incidence of HFpEF in younger individuals. Therefore, this study aimed to develop an easy-to-use nomogram with non-invasive indices that can be used in outpatient clinics in Taiwan to quickly estimate the probability of HFpEF and help decide whether further invasive cardiopulmonary exercise test (CPET) is needed.

METHODS

Outpatients with unexplained dyspnea and fatigue were recruited divided into HFpEF (n = 64) and non-HFpEF (n = 34) groups based on invasive CPET and echocardiography. Multivariate logistic regression analyses identified independent noninvasive variables for developing an HFpEF nomogram. The nomogram's performance was assessed and validated using the concordance index (C-index), area under the curve (AUC), calibration curves, and decision curve analysis.

RESULTS

Multivariate logistic regression analyses identified five independent noninvasive variables for developing an HFpEF nomogram, including dyslipidemia (OR = 5.264, p = 0.010), diabetes (OR = 3.929, p = 0.050), left atrial area (OR = 1.130, p = 0.046), hemoglobin <13 g/dL (OR = 5.372, p = 0.010), and NT-proBNP ≥245 pg/mL (OR = 5.108, p = 0.027). The nomogram showed good discriminatory ability (C-index = 0.842) and calibration performance (p = 0.873) and high net benefit (0.1-0.95). Notably, the HFpEF nomogram showed better diagnostic accuracy than the H2FPEF score model in predicting Taiwanese HFpEF patients (AUC: 0.873 vs. 0.608, p = 0.0006).

CONCLUSION

The noninvasive HFpEF nomogram provides a preliminary estimation of the probability of HFpEF in Taiwanese outpatients with unexplained dyspnea and fatigue, which may help the decision-making on further invasive CPET.

Prostanoids in Cardiac and Vascular Remodeling

Prostanoids are biologically active lipids generated from arachidonic acid by the action of the COX (cyclooxygenase) isozymes. NSAIDs, which reduce the biosynthesis of prostanoids by inhibiting COX activity, are effective anti-inflammatory, antipyretic, and analgesic drugs. However, their use is limited by cardiovascular adverse effects, including myocardial infarction, stroke, hypertension, and heart failure. While it is well established that NSAIDs increase the risk of atherothrombotic events and hypertension by suppressing vasoprotective prostanoids, less is known about the link between NSAIDs and heart failure risk. Current evidence indicates that NSAIDs may increase the risk for heart failure by promoting adverse myocardial and vascular remodeling. Indeed, prostanoids play an important role in modulating structural and functional changes occurring in the myocardium and in the vasculature in response to physiological and pathological stimuli. This review will summarize current knowledge of the role of the different prostanoids in myocardial and vascular remodeling and explore how maladaptive remodeling can be counteracted by targeting specific prostanoids.

Inhaled prostacyclin analogues in COVID-19 associated acute respiratory distress syndrome: scientific rationale

BACKGROUND

COVID-19 associated acute respiratory distress syndrome (CARDS) is a severe form of SARS CoV-2 infection and affects about 15-30% of hospitalized patients with a high mortality rate. Growing research and data suggest several available drugs with appropriate pharmacological effects to treat COVID-19.

MAIN BODY

Prostacyclin analogues are regiments for pulmonary artery hypertension. Prostacyclin analogues are expected to be beneficial in treating CARDS based on at least four rationales: (1) inhaled prostacyclin analogues improve oxygenation, V/Q mismatch, and act as an ARDS therapy alternative; (2) it alleviates direct SARS-CoV-2-related coagulopathy; (3) increases nitric oxide production; and (4) possible anti-inflammatory effect. Prostacyclin analogues are available in oral, intravenous, and inhaled forms. The inhaled form has the advantage over other forms, such as parenteral administration risks. Previously, a meta-analysis demonstrated the beneficial effects of inhaled prostaglandins for ARDS treatment, such as improved PaO2/FiO2 and PaO2 along with reduced pulmonary artery pressure. Currently, two ongoing randomized controlled trials are evaluating inhaled epoprostenol (VPCOVID [NCT04452669]) and iloprost (ILOCOVID [NCT04445246]) for severe COVID-19 patients.

CONCLUSIONS

Inhaled prostacyclin could be considered in patients with refractory, life-threatening hypoxia despite standard management.

Current Status of Pharmacologic and Nonpharmacologic Therapy in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a significantly symptomatic disease and has a poor prognosis similar to that of heart failure with reduced ejection fraction (HFrEF). Contrary to HFrEF, HFpEF is difficult to diagnose, and the recommended diagnostic algorithm of HFpEF is complicated. Several therapies for HFpEF have failed to reduce mortality or morbidity. HFpEF is thought to be a complex and heterogeneous systemic disorder that has various phenotypes and multiple comorbidities. Therefore, therapeutic strategies of HFpEF need to change depending on the phenotype of the patient. This review highlights the pharmacologic and nonpharmacologic treatment of HFpEF.