Bleeding events in pulmonary arterial hypertension

Medical Emergencies in Pulmonary Hypertension

The management of acute medical emergencies in patients with pulmonary hypertension (PH) can be challenging. Patients with preexisting PH can rapidly deteriorate due to right ventricular decompensation when faced with acute physiological challenges that would usually be considered low-risk scenarios. This review considers the assessment and management of acute medical emergencies in patients with PH, encompassing both pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), acknowledging these comprise the more severe groups of PH. Management protocols are described in a systems-based approach. Respiratory emergencies include pulmonary embolism, airways disease, and pneumonia; cardiac emergencies including arrhythmia and chest pain with acute myocardial infarction are discussed, alongside PH-specific emergencies such as pulmonary artery dissection and extrinsic coronary artery compression by a dilated proximal pulmonary artery. Other emergencies including sepsis, severe gastroenteritis with dehydration, syncope, and liver failure are also considered. We propose management recommendations for medical emergencies based on available evidence, international guidelines, and expert consensus. We aim to provide advice to the specialist alongside the generalist, and emergency doctors, nurses, and acute physicians in nonspecialist centers. A multidisciplinary team approach is essential in the management of patients with PH, and communication with local and specialist PH centers is paramount. Close hemodynamic monitoring during medical emergencies in patients with preexisting PH is vital, with early referral to critical care recommended given the frequent deterioration and high mortality in this setting.

Effects of bergapten on the pharmacokinetics of macitentan in rats both in vitro and in vivo

Macitentan was approved by the United States Food and Drug Administration (FDA) in 2013 for the treatment of pulmonary arterial hypertension (PAH). Bergapten is a furanocoumarin that is abundant in Umbelliferae and Rutaceae plants and is widely used in many Chinese medicine prescriptions. Considering the possible combination of these two compounds, this study is aimed to investigate the effects of bergapten on the pharmacokinetics of macitentan both in vitro and in vivo. Rat liver microsomes (RLMs), human liver microsomes (HLMs), and recombinant human CYP3A4 (rCYP3A4) were used to investigate the inhibitory effects and mechanisms of bergapten on macitentan in vitro. In addition, pharmacokinetic parameters were also studied in vivo. Rats were randomly divided into two groups (six rats per group), with or without bergapten (10 mg/kg), and pretreated for 7 days. An oral dose of 20 mg/kg macitentan was administered to each group 30 min after bergapten or 0.5% CMC-Na administration on day 7. Blood was collected from the tail veins, and the plasma concentrations of macitentan and its metabolites were assessed by ultra-performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS). Finally, we analyzed the binding force of the enzyme and two small ligands by in silico molecular docking to verify the inhibitory effects of bergapten on macitentan. The in vitro results revealed that the IC₅₀ values for RLMs, HLMs, and rCYP3A4 were 3.84, 17.82 and 12.81 μM, respectively. In vivo pharmacokinetic experiments showed that the AUC_(0-t), AUC_(0-∞), and C_max of macitentan in the experimental group (20,263.67 μg/L*h, 20,378.31 μg/L*h and 2,999.69 μg/L, respectively) increased significantly compared with the control group (7,873.97 μg/L*h, 7,897.83 μg/L*h and 1,339.44 μg/L, respectively), while the CL_z/F (1.07 L/h/kg) of macitentan and the metabolite-parent ratio (MR) displayed a significant decrease. Bergapten competitively inhibited macitentan metabolism in vitro and altered its pharmacokinetic characteristics in vivo. Further molecular docking analysis was also consistent with the experimental results. This study provides a reference for the combined use of bergapten and macitentan in clinical practice.

Riociguat inhibits ultra-large VWF string formation on pulmonary artery endothelial cells from chronic thromboembolic pulmonary hypertension patients

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by elevated pulmonary arterial pressure and organized thrombi within pulmonary arteries. Riociguat is a soluble guanylate cyclase stimulator and is approved for patients with inoperable CTEPH or residual pulmonary hypertension after pulmonary endarterectomy (PEA). Previous work suggested that riociguat treatment is associated with an increased risk of bleeding, although the mechanism is unclear. The aim of this study is to assess how riociguat affects primary hemostasis by studying its effect on the interaction between platelets and endothelial cells derived from CTEPH patients. Pulmonary artery endothelial cells (PAECs) were isolated from thrombus-free regions of PEA material. Purified PAECs were cultured in flow chambers and were stimulated with 0.1 and 1 µM riociguat for 24 h before flow experiments. After stimulation with histamine, PAECs were exposed to platelets under shear stress. Platelet adhesion and expression of von Willebrand Factor (VWF) were evaluated to assess the role of riociguat in hemostasis. Under dynamic conditions, 0.1 and 1.0 µM of riociguat suppressed platelet adhesion on the surface of PAECs. Although riociguat did not affect intracellular expression and secretion of VWF, PAECs stimulated with riociguat produced fewer VWF strings than unstimulated PAECs. Flow cytometry suggested that decreased VWF string formation upon riociguat treatment may be associated with suppressed cell surface expression of P-selectin, a protein that stabilizes VWF anchoring on the endothelial surface. In conclusion, Riociguat inhibits VWF string elongation and platelet adhesion on the surface of CTEPH-PAECs, possibly by reduced P-selectin cell surface expression.

Utility of Endoscopy in Hospitalized Patients with Gastrointestinal Hemorrhage and Pulmonary Hypertension

BACKGROUND

Gastrointestinal hemorrhage (GIH) has been reported as one of the most common GI complications in patients with pulmonary hypertension (PH). There is paucity of data on the national burden of GIH in patients with PH. We aimed to assess the prevalence, trends and outcomes of endoscopic interventions in patients with PH who were admitted with GIH.

METHOD

We queried National Inpatient Sample (NIS) database from 2005 to 2014 and identified the patients hospitalized with primary or secondary discharge diagnosis of PH (ICD 9 CM Code: 416.0, 416.8, and 416.9). Using Clinical Classification Software Coding system (153) patients with concurrent diagnosis of GIH were then identified. We studied the prevalence and trends of GIH in PH, factors associated with GIH, use of endoscopy, factors associated with utilization of endoscopic interventions, endoscopy outcomes including mortality, and overall healthcare burden.

RESULTS

Out of 7,586,973 PH hospitalizations 3.2% (N = 246,358) had concurrent GIH, with a rising prevalence of GIH in PH patients during the last decade. Clinical predictors for GIH in PH included older age, congestive heart failure, anticoagulation therapy and concurrent alcohol abuse. Mean length of stay (LOS) in PH patients hospitalized with GIH was significantly higher than without GIH (8.6 vs. 6.4 days, p < 0.01) along with a significant increase in hospitalization cost ($20,189 vs. $14,807, p < 0.01). Similarly, odds of in-hospital mortality increase by ~ 1.5 times in PH patients with GIH than those without it (adjusted odds ratio [aOR: 1.45, 95%CI: 1.43-1.47]). Endoscopic interventions were performed in 48.6% of patients with PH and GIH during their hospitalization. Older patients were more likely to undergo endoscopy, as well as the patients who received blood transfusion, and those with hypovolemic shock. Patients with acute respiratory failure and acute renal failure were less likely to get endoscopy. Mean LOS in patients undergoing endoscopic intervention was significantly higher than those who did not receive any intervention (8.7 vs. 8.4 days, p < 0.01), without a substantial increase in hospitalization cost ($20,344 vs. $20,041, p < 0.01). Also, there was a significant decrease in in-hospital mortality in patients undergoing endoscopic interventions.

CONCLUSION

Concurrent GIH in patients with PH increases length of stay; healthcare costs and increases in-hospital mortality. Use of endoscopic interventions in these patients is associated with reduced length of stay, in-hospital mortality without significantly increasing the overall health care burden and should be considered in hospitalized patients with PH who are admitted with GIH. Future studies comparing GIH patients with and without PH should be done to assess if PH is a risk factor for worse outcomes.

CLINICAL TRIAL REGISTRATION NUMBER

No IRB required due to use of national de-identified data.

Impact of Pulmonary Hypertension on In-Hospital Outcomes and 30-Day Readmissions Following Percutaneous Coronary Interventions

OBJECTIVE

To evaluate the impact of pulmonary hypertension (PH) on percutaneous coronary intervention (PCI) outcomes and 30-day all-cause readmissions by analyzing a national database.

METHODS

We queried the 2014 National Readmissions Database to identify patients undergoing PCI using International Classification of Diseases, Ninth Revision, Clinical Modification codes. These patients were then subcategorized based on the coded presence or absence of PH and further analyzed to determine the impact of PH on clinical outcomes, health care use, and 30-day readmissions.

RESULTS

Among 599,490 patients hospitalized for a PCI in 2014, 19,348 (3.2%) had concomitant PH. At baseline, these patients were older with a higher burden of comorbidities. Patients with PH had longer initial hospitalizations and higher 30-day readmission rates and mortality than their non-PH counterparts. This was largely driven by cardiac causes, most commonly heart failure (20.3% vs 9.0%, P<.001) and non-ST-segment elevation myocardial infarction. Recurrent coronary events (17.5% vs 9.5%, P<.05) including ST-segment elevation myocardial infarction predominated in the non-PH group.

CONCLUSION

Patients with PH undergoing PCI are a high-risk group in terms of mortality and 30-day readmission rates. Percutaneous coronary intervention in patients with PH is associated with higher rates of recurrent heart failure and non-ST-segment elevation myocardial infarction, rather than recurrent coronary events or ST-segment elevation myocardial infarction. This perhaps indicates a predominance of demand ischemia and heart failure syndromes rather than overt atherothrombosis in the etiology of chest pain in these patients.

Complications associated with the use of oral anticoagulation in patients with pulmonary arterial hypertension from two referral centers

Anticoagulants are widely used in patients with pulmonary arterial hypertension (PAH) to prolong survival. However, there is a lack of robust evidence demonstrating the benefits of anticoagulants in PAH patients and very little is known about the complications of their use in this population. The objective of this study is to compare the safety of routine administration of oral anticoagulants between PAH patients who were and were not treated with oral anticoagulants. This observational, retrospective cohort study included consecutive patients with confirmed PAH from two centers: Brigham and Women's Hospital in Boston and Hospital Universitario La Paz in Madrid from January 2009 to August 2015. The study group comprised patients who received therapeutic anticoagulation; patients who had never received anticoagulants were placed in the control group. Of the 201 included patients, 60.2% were treated with oral anticoagulants and 39.8% were not treated. The hazard ratio for major bleeding was 2.7 (95% confidence interval [CI] = 1.1-6.8; P = 0.036). The incidence rate for the anticoagulation group was 4.7 per 100 patient-years (95% CI = 2.5-8.0). The most frequent major hemorrhage was gastrointestinal bleeding with 24 cases (72.7%). Prior bleeding, poor anticoagulation, HAS-BLED score ≥3, diabetes, and number of medications were factors that increased the risk of major bleeding in patients using anticoagulants. The harmful effects of anticoagulants could outweigh the benefits in PAH patients. Therefore, anticoagulants should be prescribed on a case-by-case basis and should not be systematically recommended.

The anticoagulant effects of warfarin and the bleeding risk associated with its use in patients with chronic thromboembolic pulmonary hypertension at a specialist center in Japan: a retrospective cohort study

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) require lifelong anticoagulation therapy. However, the bleeding risk and recurrence of venous thromboembolism (VTE) in CTEPH patients who are administered warfarin have not been adequately evaluated. The purpose of this study was to evaluate the risk of clinically relevant bleeding, recurrent VTE, and clinical worsening in patients with CTEPH who were administered warfarin.

The clinical records of 72 patients with CTEPH who regularly visited our institution and were administered warfarin were retrospectively reviewed between 1 January 2011 and 31 December 2015. We investigated the incidence of clinically relevant bleeding events, recurrent VTE, and hospitalization for the deterioration of pulmonary hypertension or right heart failure (RHF) during the observation period.

The mean observation period for the 72 patients was 3.60 ± 1.60 person-years. Clinically relevant bleeding, RHF, and recurrent VTE occurred in 21 (29.2%), eight (11.1%), and three (4.2%) of 72 patients, respectively, and the incidence rates for these events were 8.1%/person-year, 3.1%/person-year, and 1.2%/person-year, respectively. The incidence rates for the major and non-major bleeding events were 5.0%/person-year and 3.9%/person-year, respectively. The incidence of clinically relevant bleeding events was 20.8%/person-year during medical treatment with a soluble guanylate cyclase stimulator. One of 35 patients (2.9%) during the post-pulmonary endarterectomy period experienced hemoptysis during observation period (> 6 months after pulmonary endarterectomy). No bleeding events occurred during the post-balloon pulmonary angioplasty period.

In conclusion, warfarin effectively prevents VTE recurrence in CTEPH patients, but its effects may be associated with a considerable bleeding risk.

Challenges and Current Efforts in the Development of Biomarkers for Chronic Inflammatory and Remodeling Conditions of the Lungs

This review discusses biomarkers that are being researched for their usefulness to phenotype chronic inflammatory lung diseases that cause remodeling of the lung's architecture. The review focuses on asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension. Bio-markers of environmental exposure and specific classes of biomarkers (noncoding RNA, metabolism, vitamin, coagulation, and microbiome related) are also discussed. Examples of biomarkers that are in clinical use, biomarkers that are under development, and biomarkers that are still in the research phase are discussed. We chose to present examples of the research in biomarker development by diseases, because asthma, COPD, and pulmonary hypertension are distinct entities, although they clearly share processes of inflammation and remodeling.

Anticoagulation in patients with pulmonary arterial hypertension: An update on current knowledge

Pulmonary hypertension is a severe clinical condition characterized by molecular and anatomic changes in pulmonary circulation. It is associated with increased pulmonary vascular resistance, which leads to right-sided heart failure if left untreated and, ultimately, death. Treatment of patients with pulmonary arterial hypertension (PAH) involves a complex strategy that takes into consideration disease severity, general and supportive measures, and combination drug regimens. Abnormalities of blood coagulation factors, anti-thrombotic factors, and the fibrinolytic system may contribute to a prothrombotic state in patients with idiopathic PAH. These physiologic changes, in concert with the presence of non-specific risk factors for venous thromboembolism such as heart failure and immobility, are thought to be the basis for oral anticoagulation in PAH. Several observational studies provide helpful information in favor of anticoagulation use in idiopathic PAH but not in other pulmonary hypertension etiologies. Guideline recommendations are based on the lack of prospective comparative trials in this regard. For that reason, large differences exist in the use of anticoagulants in different countries and centers. More studies should be carried out to clarify the risks and the potential benefits of anticoagulant use in a heterogeneous population of patients who are already at considerable life risk.

Anticoagulation and Survival in Pulmonary Arterial Hypertension

Background—

For almost 30 years, anticoagulation has been recommended for patients with idiopathic pulmonary arterial hypertension (IPAH). Supporting evidence, however, is limited, and it is unclear whether this recommendation is still justified in the modern management era and whether it should be extended to patients with other forms of pulmonary arterial hypertension (PAH).

Methods and Results—

We analyzed data from Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA), an ongoing European pulmonary hypertension registry. Survival rates of patients with IPAH and other forms of PAH were compared by the use of anticoagulation. The sample consisted of 1283 consecutively enrolled patients with newly diagnosed PAH. Anticoagulation was used in 66% of 800 patients with IPAH and in 43% of 483 patients with other forms of PAH. In patients with IPAH, there was a significantly better 3-year survival ( P =0.006) in patients on anticoagulation compared with patients who never received anticoagulation, albeit the patients in the anticoagulation group had more severe disease at baseline. The survival difference at 3 years remained statistically significant ( P =0.017) in a matched-pair analysis of n=336 IPAH patients. The beneficial effect of anticoagulation on survival of IPAH patients was confirmed by Cox multivariable regression analysis (hazard ratio, 0.79; 95% confidence interval, 0.66–0.94). In contrast, the use of anticoagulants was not associated with a survival benefit in patients with other forms of PAH.

Conclusions—

The present data suggest that the use of anticoagulation is associated with a survival benefit in patients with IPAH, supporting current treatment recommendations. The evidence remains inconclusive for other forms of PAH.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01347216.

Standard nonspecific therapies in the management of pulmonary arterial hypertension

Recent advances in pulmonary arterial hypertension (PAH) research have created a new era of PAH-specific therapies. Although these therapeutics have revolutionized PAH therapy, their innovation was predated by supportive but nonspecific medical therapies adapted from their use in more common cardiopulmonary diseases. These therapies include oxygen therapy, diuretics, digoxin, anticoagulation, and high-dose calcium channel blockers. Expert opinion continues to support the use of adjunct therapies based on current pathologic understandings of PAH combined with some evidence extrapolated from small studies. This article discusses why these therapies continue to play an important role in the treatment of patients with PAH.