Real-world data of patients affected by advanced heart failure treated with implantable cardioverter defibrillator and left ventricular assist device: Results of a multicenter observational study.

BACKGROUND: Left ventricular assist device (L-VAD) implantation is increasingly used in patients with heart failure (HF) and most patients also have an implantable cardioverter defibrillator (ICD). Limited data are available on the incidence of ICD therapies and complications in this special setting. The aim of this study was to analyze the real-world incidence and predictors of ICD therapies, complications and interactions between ICD and L-VAD. METHODS: We conducted a multicenter retrospective observational study in patients with advanced HF implanted with ICD and a continuous-flow L-VAD, followed-up in five advanced HF centers in Northern Italy. RESULTS: A total of 234 patients (89.7% male, median age 59, 48.3% with ischemic etiology) were enrolled. After a median follow-up of 21 months, 66 patients (28.2%) experienced an appropriate ICD therapy, 22 patients (9.4%) an inappropriate ICD therapy, and 17 patients (7.3%) suffered from an interaction between ICD and L-VAD. The composite outcome of all ICD-related complications was reported in 41 patients (17.5%), and 121 (51.7%) experienced an L-VAD-related complication. At multivariable analysis, an active ventricular tachycardia (VT) zone and a prior ICD generator replacement were independent predictors of ICD therapies and of total ICD-related complications, respectively. CONCLUSIONS: Real-world patients with both L-VAD and ICD experience a high rate of ICD therapies and complications. Our findings suggest the importance of tailoring device programming in order to minimize the incidence of unnecessary ICD therapies, thus sparing the need for ICD generator replacement, a procedure associated to a high risk of complications.

Fulminant Myocarditis Temporally Associated with COVID-19 Vaccination.

PURPOSE OF REVIEW: Coronavirus disease-2019 (COVID-19) vaccines have been related to rare cases of acute myocarditis, occurring between 1 in 10,000 and 1 in 100,000 individuals, approximately. Incidence of COVID-19 vaccine-associated myocarditis varies with age, sex, and type of vaccine. Although most patients with acute myocarditis temporally associated with COVID-19 vaccines have an uneventful course, a small subpopulation presents with cardiogenic shock (termed fulminant myocarditis [FM]). This review explored the prevalence, clinical presentation, management, and prognosis of COVID-19 vaccine-associated acute myocarditis, specifically focusing on FM and comparing patients with fulminant versus non-fulminant myocarditis. RECENT FINDINGS: Cases of FM represent about 2-4% (0 to 7.5%) of COVID-19 vaccine-associated acute myocarditis cases, and mortality is around 1%, ranging between 0 and 4.4%. First, we identified 40 cases of FM up to February 2023 with sufficient granular data from case reports and case series of COVID-19 vaccine-associated acute myocarditis that occurred within 30 days from the last vaccine injection. This population was compared with 294 cases of non-fulminant acute myocarditis identified in the literature during a similar time. Patients with FM were older (48 vs. 27 years), had a larger proportion of women (58% vs. 9%), and mainly occurred after the first shot compared with non-fulminant cases (58% vs. 16%). The reported mortality was 27% (11 out of 40), in line with non-vaccine-associated fulminant myocarditis. These data were in agreement with 36 cases of FM from a large Korean registry. Herein, we reviewed the clinical features, imaging results, and histological findings of COVID-19 vaccine-associated fulminant myocarditis. In conclusion, COVID-19 vaccine-associated FM differs from non-fulminant forms, suggesting potential specific mechanisms in these rare and severe forms. Mortality in vaccine-associated FM remains high, in line with other forms of FM.

Advanced heart failure: from definitions to therapeutic options.

Advanced heart failure (AHF) represents an ominous stage of heart failure (HF), where the expected prognosis remains poor regardless of the improvement in medical knowledge. In this review, we summarize the definition, prognosis, physiopathology, and clinical/therapeutic management of the disease, focusing on the fast and timely referral of the patient to the AHF facilities. We provide an insight of the diagnostic and therapeutic 'work up' performed in an Italian AHF hub, implying a deep phenotypical patients characterization in order to evaluate candidacy to the therapeutic gold standards as heart transplantation (HTx) and left ventricular assist device (LVAD).

Scenarios in precision medicine: proteomics in heart failure.

Proteomics in heart failure (HF) is aimed to study and identify proteins involved in the pathophysiology of this clinical syndrome. Proteins have a role as diagnostic, prognostic and therapeutic markers. This review will unravel the developments and impact of proteomics in HF, focusing on its role in the diagnosis, prognosis and definition of new HF therapies. Proteomics promises to change our approach to HF in the near future, accepting the need for precision medicine, tailored on the characteristics of the single patient.

State-of-the-Art of Endomyocardial Biopsy on Acute Myocarditis and Chronic Inflammatory Cardiomyopathy.

PURPOSE OF REVIEW: Histologic evidence of myocardial inflammatory infiltrate not secondary to an ischemic injury is required by current diagnostic criteria to reach a definite diagnosis of myocarditis. Endomyocardial biopsy (EMB) is therefore often indicated for the diagnosis of myocarditis, although it may lack sufficient sensitivity considering the limited possibility of myocardial sampling. Improving the diagnostic yield and utility of EMB is of high priority in the fields of heart failure cardiology and myocarditis in particular. The aim of the present review is to highlight indications, strengths, and shortcomings of current EMB techniques, and discuss innovations currently being tested in ongoing clinical studies, especially in the setting of acute myocarditis and chronic inflammatory cardiomyopathy. RECENT FINDINGS: EMB provides unique diagnostic elements and prognostic information which can effectively guide the treatment of myocarditis. Issues affecting the diagnostic performance in the setting of acute myocarditis and chronic inflammatory cardiomyopathies will be discussed in this review in the light of recent expert consensus documents on the management of these conditions and on indication to EMB. Recent innovations using electroanatomic mapping (EAM)-guided EMB and fluoroscopic-guided EMB during temporary mechanical circulatory support have improved the utility of the procedure. EMB remains an important diagnostic test whose results need to be interpreted in the context of (1) clinical pre-test probability, (2) timing of sampling, (3) quality of sampling (4) site of sampling, (5) histologic type of myocarditis, and (6) analytic methods that are applied. Herein we will review these caveats as well as perspectives and innovations related to the use of this diagnostic tool.

Nonresponse to Acute Vasodilator Challenge and Prognosis in Heart Failure With Pulmonary Hypertension.

BACKGROUND: An acute vasodilator challenge is recommended in patients with heart failure and pulmonary hypertension during heart transplant evaluation. The aim of the study was to assess which hemodynamic parameters are associated with nonresponsiveness to the challenge. METHODS AND RESULTS: This study is a retrospective analysis of 402 patients with heart failure with pulmonary hypertension who underwent right heart catheterization and a pulmonary vasodilator challenge. Among the 140 who fulfilled the transplant guidelines eligibility criteria for the vasodilator challenge, 38 were responders and 102 nonresponders. At multivariable analysis, a diastolic blood pressure of <70 mm Hg, pulmonary vascular resistance of >5 Woods units, and pulmonary artery compliance of <1.2 mL/mm Hg were independently associated with poor response to vasodilator challenge (all P < .001). The presence of any 2 of these 3 conditions was associated with a 90% probability of being a nonresponder. The covariate-adjusted hemodynamic predictors of death in the entire population were a low baseline systolic blood pressure (P = .0017) and a low baseline right ventricular stroke work index (P = .0395). CONCLUSIONS: In patients with heart failure and pulmonary hypertension, low pulmonary arterial compliance, high pulmonary vascular resistance, and low diastolic blood pressure predict the nonresponsiveness to acute vasodilator challenge whilst a poor right ventricular function predicts a dismal prognosis.

Survival and Left Ventricular Function Changes in Fulminant Versus Nonfulminant Acute Myocarditis.

BACKGROUND: Previous reports have suggested that despite their dramatic presentation, patients with fulminant myocarditis (FM) might have better outcome than those with acute nonfulminant myocarditis (NFM). In this retrospective study, we report outcome and changes in left ventricular ejection fraction (LVEF) in a large cohort of patients with FM compared with patients with NFM. METHODS: The study population consists of 187 consecutive patients admitted between May 2001 and November 2016 with a diagnosis of acute myocarditis (onset of symptoms <1 month) of whom 55 required inotropes and/or mechanical circulatory support (FM) and the remaining 132 were hemodynamically stable (NFM). We also performed a subanalysis in 130 adult patients with acute viral myocarditis and viral prodrome within 2 weeks from the onset, which includes 34 with FM and 96 with NFM. Patients with giant-cell myocarditis, eosinophilic myocarditis, or cardiac sarcoidosis and those <15 years of age were excluded from the subanalysis. RESULTS: In the whole population (n=187), the rate of in-hospital death or heart transplantation was 25.5% versus 0% in FM versus NFM, respectively (P<0.0001). Long-term heart transplantation-free survival at 9 years was lower in FM than NFM (64.5% versus 100%, log-rank P<0.0001). Despite greater improvement in LVEF during hospitalization in FM versus NFM forms (median, 32% [interquartile range, 20%-40%] versus 3% [0%-10%], respectively; P<0.0001), the proportion of patients with LVEF <55% at last follow-up was higher in FM versus NFM (29% versus 9%; relative risk, 3.32; 95% confidence interval, 1.45-7.64, P=0.003). Similar results for survival and changes in LVEF in FM versus NFM were observed in the subgroup (n=130) with viral myocarditis. None of the patients with NFM and LVEF ≥55% at discharge had a significant decrease in LVEF at follow-up. CONCLUSIONS: Patients with FM have an increased mortality and need for heart transplantation compared with those with NFM. From a functional viewpoint, patients with FM have a more severely impaired LVEF at admission that, despite steep improvement during hospitalization, remains lower than that in patients with NFM at long-term follow-up. These findings also hold true when only the viral forms are considered and are different from previous studies showing better prognosis in FM.

Management of cardiogenic shock in acute decompensated chronic heart failure: The ALTSHOCK phase II clinical trial.

Management of acute decompensated heart failure patients presenting with cardiogenic shock (CS) is not straightforward, as few data are available from clinical trials. Stabilization before left ventricle assist device (LVAD) or heart transplantation (HTx) is strongly advocated, as patients undergoing LVAD implant or HTx in critical status have worse outcomes. This was a multicenter phase II study with a Simon 2-stage design, including 24 consecutive patients treated with low-moderate epinephrine doses, whose refractory CS prompted implantation of intra-aortic balloon pump (IABP) which was subsequently upgraded with peripheral venoarterial extracorporeal membrane oxygenation. At admission, patients had severe left ventricular dysfunction and overt CS, 7 patients could be managed only with inotropic therapy, and 16 patients were transitioned to IABP and 1 to IABP and venoarterial extracorporeal membrane oxygenation; the median duration of epinephrine therapy was 7 days (interquartile range 6-15), and the median dose was 0.08 µg/kg/min (interquartile range 0.05-0.1); 21 patients (87.5%) survived at 60 days (primary outcome); among them, 13 (61.9%) underwent LVAD implantation, 2 (9.5%) underwent HTx, and 6 (28.6%) improved on medical treatment, indicating that early and intensive treatment of CS in chronic advanced heart failure patients with low-dose epinephrine and timely short-term mechanical circulatory support leads to satisfactory outcomes.

Acute and Fulminant Myocarditis: a Pragmatic Clinical Approach to Diagnosis and Treatment.

PURPOSE OF REVIEW: To review the clinical features of acute myocarditis, including its fulminant presentation, and present a pragmatic approach to the diagnosis and treatment, considering indications of American and European Scientific Statements and recent data derived by large contemporary registries. RECENT FINDINGS: Patients presenting with acute uncomplicated myocarditis (i.e., without left ventricular dysfunction, heart failure, or ventricular arrhythmias) have a favorable short- and long-term prognosis: these findings do not support the indication to endomyocardial biopsy in this clinical scenario. Conversely, patients with complicated presentations, especially those with fulminant myocarditis, require an aggressive and comprehensive management, including endomyocardial biopsy and availability of advanced therapies for circulatory support. Although several immunomodulatory or immunosuppressive therapies have been studied and are actually prescribed in the real-world practice, their effectiveness has not been clearly demonstrated. Patients with specific histological subtypes of acute myocarditis (i.e., giant cell and eosinophilic myocarditis) or those affected by sarcoidosis or systemic autoimmune disorders seem to benefit most from immunosuppression. On the other hand, no clear evidence supports the use of immunosuppressive agents in patients with lymphocytic acute myocarditis, even though small series suggest a potential benefit. Acute myocarditis is a heterogeneous condition with distinct pathophysiological pathways. Further research is mandatory to identify factors and mechanisms that may trigger/maintain or counteract/repair the myocardial damage, in order to provide a rational for future evidence-based treatment of patients affected by this condition.

Mid-term survival after continuous-flow left ventricular assist device versus heart transplantation.

There is a paucity of data about mid-term outcome of patients with advanced heart failure (HF) treated with left ventricular assist device (LVAD) in Europe, where donor shortage and their aging limit the availability and the probability of success of heart transplantation (HTx). The aim of this study is to compare Italian single-centre mid-term outcome in prospective patients treated with LVAD vs. HTx. We evaluated 213 consecutive patients with advanced HF who underwent continuous-flow LVAD implant or HTx from 1/2006 to 2/2012, with complete follow-up at 1 year (3/2013). We compared outcome in patients who received a LVAD (n = 49) with those who underwent HTx (n = 164) and in matched groups of 39 LVAD and 39 HTx patients. Patients that were treated with LVAD had a worse risk profile in comparison with HTx patients. Kaplan-Meier survival curves estimated a one-year survival of 75.5 % in LVAD vs. 82.3 % in HTx patients, a difference that was non-statistically significant [hazard ratio (HR) 1.46; 95 % confidence interval (CI) 0.74-2.86; p = 0.27 for LVAD vs. HTx]. After group matching 1-year survival was similar between LVAD (76.9 %) and HTx (79.5 %; HR 1.15; 95 % CI 0.44-2.98; p = 0.78). Concordant data was observed at 2-year follow-up. Patients treated with LVAD as bridge-to-transplant indication (n = 22) showed a non significant better outcome compared with HTx with a 95.5 and 90.9 % survival, at 1- and 2-year follow-up, respectively. Despite worse preoperative conditions, survival is not significantly lower after LVAD than after HTx at 2-year follow-up. Given the scarce number of donors for HTx, LVAD therapy represents a valid option, potentially affecting the current allocation strategy of heart donors also in Europe.

Heart Failure Management through Telehealth: Expanding Care and Connecting Hearts.

Heart failure (HF) is a leading cause of morbidity worldwide, imposing a significant burden on deaths, hospitalizations, and health costs. Anticipating patients' deterioration is a cornerstone of HF treatment: preventing congestion and end organ damage while titrating HF therapies is the aim of the majority of clinical trials. Anyway, real-life medicine struggles with resource optimization, often reducing the chances of providing a patient-tailored follow-up. Telehealth holds the potential to drive substantial qualitative improvement in clinical practice through the development of patient-centered care, facilitating resource optimization, leading to decreased outpatient visits, hospitalizations, and lengths of hospital stays. Different technologies are rising to offer the best possible care to many subsets of patients, facing any stage of HF, and challenging extreme scenarios such as heart transplantation and ventricular assist devices. This article aims to thoroughly examine the potential advantages and obstacles presented by both existing and emerging telehealth technologies, including artificial intelligence.

Gaps in evidence in the management of patients with intermediate-risk pulmonary arterial hypertension: Considerations following the ESC/ERS 2022 guidelines.

A comprehensive evaluation of risk, using multiple indices, is necessary to provide reliable prognostic information and guide therapy in pulmonary arterial hypertension (PAH). The current ESC/ERS guidelines suggest using a three-strata model for incident (newly diagnosed) patients and a four-strata model for prevalent patients with PAH. The four-strata model serves as a fundamental risk-stratification tool and relies on a minimal dataset of indicators that must be considered during follow-up. Nevertheless, there are still areas of vagueness and ambiguity when classifying and managing patients in the intermediate-risk category. For these patients, considerations should include right heart imaging, hemodynamics, as well as individual factors such as age, sex, genetic profile, disease type, comorbidities, and kidney function. The aim of this report is to present case studies, with a specific focus on patients ultimately classified as intermediate risk. We aim to emphasize the challenges and complexities encountered in the realms of diagnosis, classification, and treatment for these particular patients.

The Exercise aNd hEArt transplant (ENEA) trial - a registry-based randomized controlled trial evaluating the safety and efficacy of cardiac telerehabilitation after heart transplant.

BACKGROUND: Heart transplant (HTx) is gold-standard therapy for patients with end-stage heart failure. Cardiac rehabilitation (CR) is a multidisciplinary intervention shown to improve cardiovascular prognosis and quality of life. The aim in this randomized controlled trial is to explore the safety and efficacy of cardiac telerehabilitation after HTx. In addition, biomarkers of rehabilitation outcomes will be identified, as data that will enable treatment to be tailored to patient phenotype. METHODS: Patients after HTx will be recruited at IRCCS S. Maria Nascente - Fondazione Don Gnocchi, Milan, Italy (n = 40). Consenting participants will be randomly allocated to either of two groups (1:1): an intervention group who will receive on-site CR followed by 12 weeks of telerehabilitation, or a control group who will receive on-site CR followed by standard homecare and exercise programme. Recruitment began on 20th May 2023 and is expected to continue until 20th May 2025. Socio-demographic characteristics, lifestyle, health status, cardiovascular events, cognitive function, anxiety and depression symptoms, and quality of life will be assessed, as well as exercise capacity and muscular endurance. Participants will be evaluated before the intervention, post-CR and after 6 months. In addition, analysis of circulating extracellular vesicles using Surface Plasmon Resonance imaging (SPRi), based on a rehabilomic approach, will be applied to both groups pre- and post-CR. CONCLUSION: This study will explore the safety and efficacy of cardiac telerehabilitation after HTx. In addition, a rehabilomic approach will be used to investigate biomolecular phenotypization in HTx patients. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT05824364.

[Pulmonary hypertension associated with left heart diseases: pathophysiology, diagnosis, treatment]. / Ipertensione polmonare associata ad insufficienza cardiaca: fisiopatologia, diagnosi, terapia.

Pulmonary hypertension (PH) is a common complication of diseases affecting the left heart, mostly found in patients suffering from heart failure. Left atrial hypertension is the initial driver of post-capillary PH. However, several mechanisms may lead in a subset of patients to structural changes in the pulmonary vessels with development of a pre-capillary component. The right ventricle may be frequently affected, leading to right ventricular failure and a worse outcome. The differential diagnosis of PH associated with left heart disease vs pulmonary arterial hypertension (PAH) is challenging in patients with cardiovascular comorbidities, risk factors for PAH and/or a preserved left ventricular ejection fraction. Multidimensional clinical phenotyping is needed to identify patients in whom hemodynamic confirmation is deemed necessary, that may be completed by provocative testing in the cath lab. In contrast with PAH, management of PH associated with left heart disease should focus on the treatment of the underlying condition. There is currently no approved therapy for PH associated with left heart disease: some PAH-specific treatments have led to an increase in adverse events in these patients.

Estimation of Right Atrial Pressure by Ultrasound-Assessed Jugular Vein Distensibility in Patients With Heart Failure.

BACKGROUND: Clinical evaluation of central venous pressure is difficult, depends on experience, and is often inaccurate in patients with chronic advanced heart failure. We assessed the ultrasound-assessed internal jugular vein (JV) distensibility by ultrasound as a noninvasive tool to identify patients with normal right atrial pressure (RAP ≤7 mm Hg) in this population. METHODS: We measured JV distensibility as the Valsalva-to-rest ratio of the vein diameter in a calibration cohort (N=100) and a validation cohort (N=101) of consecutive patients with chronic heart failure with reduced ejection fraction who underwent pulmonary artery catheterization for advanced heart failure therapies workup. RESULTS: A JV distensibility threshold of 1.6 was identified as the most accurate to discriminate between patients with RAP ≤7 versus >7 mm Hg (area under the receiver operating characteristic curve, 0.74 [95% CI, 0.64-0.84]) and confirmed in the validation cohort (receiver operating characteristic, 0.82 [95% CI, 0.73-0.92]). A JV distensibility ratio >1.6 had predictive positive values of 0.86 and 0.94, respectively, to identify patients with RAP ≤7 mm Hg in the calibration and validation cohorts. Compared with patients from the calibration cohort with a high JV distensibility ratio (>1.6; n=42; median RAP, 4 mm Hg; pulmonary capillary wedge pressure, 11 mm Hg), those with a low JV distensibility ratio (≤1.6; n=58; median RAP, 8 mm Hg; pulmonary capillary wedge pressure, 22 mm Hg; P<0.0001 for both) were more likely to die or undergo a left ventricular assist device implant or heart transplantation (event rate at 2 years: 42.7% versus 18.2%; log-rank P=0.034). CONCLUSIONS: Ultrasound-assessed JV distensibility identifies patients with chronic advanced heart failure with normal RAP and better outcomes. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03874312.

[ANMCO/SIC Consensus statement on pulmonary arterial hypertension]. / Documento di consenso ANMCO/SIC sull'ipertensione arteriosa polmonare.

Pulmonary hypertension (PH) is a frequent pathological condition worldwide, mainly secondary to cardiovascular and respiratory diseases, with a poor prognosis. Pulmonary arterial hypertension (PAH) is a rare form that affects the arterial pulmonary vasculature. PH and PAH are characterized by non-specific symptoms and a progressive increase of pulmonary vascular resistance that results in progressive, sometimes irreversible, right ventricular dysfunction. In recent years, a growing medical and social commitment on this disease allowed more accurate diagnosis in shorter times. However, the gap between guidelines and clinical practice remains a challenge for all medical doctors involved in the disease management. Considering the needs to share and describe diagnostic and therapeutic pathways, to measure the results obtained and to address the economical and organizational problems of this disease, all involved figures should collaborate to improve its prognostic impact and health expenses. In this consensus document, the PH experts of the Italian Association of Hospital Cardiologists (ANMCO) together with those of the Italian Society of Cardiology (SIC), address 1) definition, classification and unmet needs of PH and PAH; 2) classification and characteristics of centers involved in the diagnosis and treatment of the disease; 3) proposal of organization of a diagnostic-therapeutic pathway, based on robust and recent scientific evidence.

Ultrasound-Assisted, Catheter-Directed Thrombolysis for Acute Intermediate/High-Risk Pulmonary Embolism: Design of the Multicenter USAT IH-PE Registry and Preliminary Results.

Catheter-based revascularization procedures were developed as an alternative to systemic thrombolysis for patients with intermediate-high- and high-risk pulmonary embolisms. USAT IH-PE is a retrospective and prospective multicenter registry of such patients treated with ultrasound-facilitated, catheter-directed thrombolysis, whose preliminary results are presented in this study. The primary endpoint was the incidence of pulmonary hypertension (PH) at follow-up. Secondary endpoints were short- and mid-term changes in the echocardiographic parameters of right ventricle (RV) function, in-hospital and all-cause mortality, and procedure-related bleeding events. Between March 2018 and July 2023, 102 patients were included. The majority were at intermediate-high-risk PE (86%), were mostly female (57%), and had a mean age of 63.7 ± 14.5 years, and 28.4% had active cancer. Echocardiographic follow-up was available for 70 patients, and in only one, the diagnosis of PH was confirmed by right heart catheterization, resulting in an incidence of 1.43% (CI 95%, 0.036-7.7). RV echocardiographic parameters improved both at 24 h and at follow-up. In-hospital mortality was 3.9% (CI 95%, 1.08-9.74), while all-cause mortality was 11% (CI 95%, 5.4-19.2). Only 12% had bleeding complications, of whom 4.9% were BARC ≥ 3. Preliminary results from the USAT IH-PE registry showed a low incidence of PH, improvement in RV function, and a safe profile.

Phenotype and outcomes according to loop diuretic use in pulmonary arterial hypertension.

AIMS: The use of loop diuretics in pulmonary arterial hypertension (PAH) is less frequent compared with heart failure. The clinical and prognostic characteristics of PAH patients according to loop diuretic use remain unexplored. In this study, we retrospectively analysed the characteristics and survival of PAH patients requiring different doses of loop diuretics. METHODS AND RESULTS: Patients diagnosed with PAH between 2001 and 2022 at seven European centres for the management of PAH. According to the median equivalent dose of furosemide in the overall cohort, patients were divided into two subgroups: no/low-dose loop diuretic and high-dose loop diuretic. Primary outcome was 5 year all-cause mortality. Among the 397 patients included, 227 (57%) were treated with loop diuretics. Median daily furosemide equivalent dose was 25 mg, and accordingly patients were divided in no/low dose (i.e. ≤25 mg, n = 257, 65%) vs. high dose (i.e. >25 mg, n = 140, 35%). Patients in the high-dose group were older, more likely to have comorbidities, and had a more severe disease according to the ESC/ERS risk category. Crude 5 year survival was significantly shorter in patients in the high-dose group, but after adjustment for age, sex, and risk category, high loop diuretic dose was not significantly associated with the primary outcome. CONCLUSIONS: Use of high dose of loop diuretics in PAH is associated with a higher burden of comorbidities, more severe disease, and worse survival. However, in PAH, the need of high loop diuretic dose is a marker of disease severity and not an independent prognostic factor.