Unmet needs and knowledge gaps in aortic stenosis: A position paper from the Heart Valve Council of the French Society of Cardiology.

Nowadays, valvular heart disease remains a significant challenge among cardiovascular diseases, affecting millions of people worldwide and exerting substantial pressure on healthcare systems. Within the spectrum of valvular heart disease, aortic stenosis is the most common valvular lesion in developed countries. Despite notable advances in understanding its pathophysiological processes, improved cardiovascular imaging techniques and expanding therapeutic options in recent years, there are still unmet needs and knowledge gaps regarding aortic stenosis pathophysiology, severity assessment, management and decision-making strategy. This review, prepared on behalf of the Heart Valve Council of the French Society of Cardiology, describes these gaps and future research perspectives to improve the outcome of patients with aortic stenosis.

Diagnostic and therapeutic practice for Heart Failure with preserved ejection fraction around the world: An international survey.

BACKGROUND AND AIMS: There is a gap in knowledge about implementing diagnostic tools and therapy for heart failure with preserved ejection fraction (HFpEF) in clinical practice. This survey aimed to assess real-world practice in HFpEF diagnosis and treatment in the international medical community. METHODS: An independent academic web-based 29-question survey was designed by a group of heart failure specialists and posted by email and through scientific societies and social networks to a broad community of physicians worldwide. RESULTS: 1.460 physicians from 95 countries answered the survey, with a mean age of 42.2±10.4 years, 39.4 % females, and 85.1 % were cardiologists. The left ventricular ejection fraction cut-off value selected for HFpEF diagnosis was 50 % for 89 % of participants. The scores for the probability of diagnosis of HFpEF were used only by 47.2 %, and H2FPEF was the most used score (31 %). Natriuretic peptides were used by 87.4 % of participants for the diagnostic workup, while the diastolic stress test was only used by 26.2 %. 54.4 % of participants chose SGLT2 inhibitors as their first drug treatment, followed by diuretics (18.6 %) and ACE inhibitors (8.4 %). CONCLUSIONS: In an international academic survey on HFpEF management, the criteria for screening and diagnosis of HFpEF patients remain aligned with classic international guidelines with a low use of diagnostic scores. SGLT2i is the leading therapeutic drug class used for this heterogeneous patient population. These results raise the need to improve education and awareness on diagnosing and managing HFpEF patients.

Post-capillary pulmonary hypertension in heart failure: impact of current definition in the PH-HF multicentre study.

BACKGROUND AND AIMS: Based on retrospective studies, the 2022 European guidelines changed the definition of post-capillary pulmonary hypertension (pcPH) in heart failure (HF) by lowering the level of mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR). However, the impact of this definition and its prognostic value has never been evaluated prospectively. METHODS: Stable left HF patients with the need for right heart catheterization were enrolled from 2010 to 2018 and prospectively followed up in this multicentre study. The impact of the successive pcPH definitions on pcPH prevalence and subgroup [i.e. isolated (IpcPH) vs. combined pcPH (CpcPH)] was evaluated. Multivariable Cox regression analysis was used to assess the prognostic value of mPAP and PVR on all-cause death or hospitalization for HF (primary outcome). RESULTS: Included were 662 HF patients were (median age 63 years, 60% male). Lowering mPAP from 25 to 20 mmHg resulted in +10% increase in pcPH prevalence, whereas lowering PVR from 3 to 2 resulted in +60% increase in CpcPH prevalence (with significant net reclassification improvement for the primary outcome). In multivariable analysis, both mPAP and PVR remained associated with the primary outcome [hazard ratio (HR) 1.02, 95% confidence interval (CI) 1.00-1.03, P = .01; HR 1.07, 95% CI 1.00-1.14, P = .03]. The best PVR threshold associated with the primary outcome was around 2.2 WU. Using the 2022 definition, pcPH patients had worse survival compared with HF patients without pcPH (log-rank, P = .02) as well as CpcPH compared with IpcPH (log-rank, P = .003). CONCLUSIONS: This study is the first emphasizing the impact of the new pcPH definition on CpcPH prevalence and validating the prognostic value of mPAP > 20 mmHg and PVR > 2 WU among HF patients.

Evidence and unresolved questions in pulmonary hypertension: Insights from the 5th French Pulmonary Hypertension Network Meeting.

Pulmonary hypertension (PH) continues to present significant challenges to the medical community, both in terms of diagnosis and treatment. The advent of the updated 2022 European Society of Cardiology (ESC) and European Respiratory Society (ERS) guidelines has introduced pivotal changes that reflect the rapidly advancing understanding of this complex disease. These changes include a revised definition of PH, updates to the classification system, and treatment algorithm. While these guidelines offer a critical framework for the management of PH, they have also sparked new discussions and questions. The 5th French Pulmonary Hypertension Network Meeting (Le Kremlin-Bicêtre, France, 2023), addressed these emergent questions and fostering a deeper understanding of the disease's multifaceted nature. These discussions were not limited to theoretical advancements but extended into the practical realms of patient management, highlighting the challenges and opportunities in applying the latest guidelines to clinical practice.

Phenotypic clustering of patients hospitalized in intensive cardiac care units: Insights from the ADDICT-ICCU study.

BACKGROUND: Intensive cardiac care units (ICCUs) were created to manage ventricular arrhythmias after acute coronary syndromes, but have diversified to include a more heterogeneous population, the characteristics of which are not well depicted by conventional methods. AIMS: To identify ICCU patient subgroups by phenotypic unsupervised clustering integrating clinical, biological, and echocardiographic data to reveal pathophysiological differences. METHODS: During 7-22 April 2021, we recruited all consecutive patients admitted to ICCUs in 39 centers. The primary outcome was in-hospital major adverse events (MAEs; death, resuscitated cardiac arrest or cardiogenic shock). A cluster analysis was performed using a Kamila algorithm. RESULTS: Of 1499 patients admitted to the ICCU (69.6% male, mean age 63.3±14.9 years), 67 (4.5%) experienced MAEs. Four phenogroups were identified: PG1 (n=535), typically patients with non-ST-segment elevation myocardial infarction; PG2 (n=444), younger smokers with ST-segment elevation myocardial infarction; PG3 (n=273), elderly patients with heart failure with preserved ejection fraction and conduction disturbances; PG4 (n=247), patients with acute heart failure with reduced ejection fraction. Compared to PG1, multivariable analysis revealed a higher risk of MAEs in PG2 (odds ratio [OR] 3.13, 95% confidence interval [CI] 1.16-10.0) and PG3 (OR 3.16, 95% CI 1.02-10.8), with the highest risk in PG4 (OR 20.5, 95% CI 8.7-60.8) (all P<0.05). CONCLUSIONS: Cluster analysis of clinical, biological, and echocardiographic variables identified four phenogroups of patients admitted to the ICCU that were associated with distinct prognostic profiles. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05063097.

Tricuspid annular plane systolic excursion over systolic pulmonary artery pressure prognostic value for in-hospital adverse events in patients hospitalized for acute coronary syndrome.

AIMS: Although several studies have shown that the right ventricular to pulmonary artery (RV-PA) coupling, assessed by the ratio between tricuspid annular plane systolic excursion and systolic pulmonary artery pressure (TAPSE/sPAP) using echocardiography, is strongly associated with cardiovascular events, its prognostic value is not established in acute coronary syndrome (ACS). We aimed to assess the in-hospital prognostic value of TAPSE/sPAP among patients hospitalized for ACS in a retrospective analysis from the prospective ADDICT-ICCU study. METHODS AND RESULTS: A total of 481 consecutive patients hospitalized in intensive cardiac care unit [mean age 65 ± 13 years, 73% of male, 46% ST-elevation myocardial infarction (STEMI)] for ACS [either STEMI or non-STEMI (NSTEMI)] with TAPSE/sPAP available were included in this prospective French multicentric study (39 centres). The primary outcome was in-hospital major adverse cardiovascular events (MACEs) defined as all-cause death, resuscitated cardiac arrest, or cardiogenic shock and occurred in 33 (7%) patients. Receiver operating characteristic curve analysis identified 0.55 mm/mmHg as the best TAPSE/sPAP cut-off to predict in-hospital MACEs. TAPSE/sPAP <0.55 was associated with in-hospital MACEs, even after adjustment with comorbidities [odds ratio (OR): 19.1, 95% confidence interval (CI) 7.78-54.8], clinical severity including left ventricular ejection fraction (OR: 14.4, 95% CI 5.70-41.7), and propensity-matched population analysis (OR: 22.8, 95% CI 7.83-97.2, all P < 0.001). After adjustment, TAPSE/sPAP <0.55 showed the best improvement in model discrimination and reclassification above traditional prognosticators (C-statistic improvement: 0.16; global χ2 improvement: 52.8; likelihood ratio test P < 0.001) with similar results for both STEMI and NSTEMI subgroups. CONCLUSION: A low RV-PA coupling defined as TAPSE/sPAP ratio <0.55 was independently associated with in-hospital MACEs and provided incremental prognostic value over traditional prognosticators in patients hospitalized for ACS. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05063097.

Comparison Between REVEAL Lite 2 and COMPERA 2.0 for Risk Stratification in Pulmonary Arterial Hypertension.

BACKGROUND: Risk stratification is the cornerstone of the management of pulmonary arterial hypertension (PAH). Current European Society of Cardiology/European Respiratory Society guidelines recommend using the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) three-strata risk model at baseline and the COMPERA 2.0 four-strata model at follow-up. However, the guidelines did not take into consideration other available risk scores such as the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) Lite 2. RESEARCH QUESTION: Is REVEAL Lite 2 better at discriminating risk than the COMPERA risk assessment models at baseline or follow-up evaluations? STUDY DESIGN AND METHODS: This study analyzed data from patients with PAH consecutively enrolled between June 2011 and February 2022 in the PAH registry at our expert Pulmonary Hypertension Center. Patients were stratified according to REVEAL Lite 2 and COMPERA three- and four-strata risk scores at baseline and follow-up to predict the composite outcome for lung transplantation or death. Receiver-operating characteristic curves in predicting the binary outcome at 3, 5, and 7 years were plotted. Areas under the curve of the scores were compared by using the χ2 test. The performance of the scores was determined according to the Harrel C statistic. RESULTS: A total of 296 patients were included for baseline and 196 for follow-up evaluation. The overall transplant-free survival in the patient population at 1, 3, 5, and 7 years was 93.6%, 81.3%, 75.1%, and 68.8%, respectively. At baseline, the C statistic of REVEAL Lite 2 was 0.74 (95% CI, 0.69-0.80), compared with 0.68 (95% CI, 0.63-0.74) for the COMPERA four-strata model and 0.63 (95% CI, 0.58-0.69) for the COMPERA three-strata model. All C statistic differences between REVEAL Lite 2 and the other models were statistically significant at baseline. INTERPRETATION: Our analysis showed that REVEAL Lite 2 was better at baseline at discriminating risk in this patient population. Future guidelines should consider including REVEAL Lite 2 in the management algorithm to help clinicians make informed decisions. Further analysis in larger cohorts could help validate these findings.

In-hospital prognostic value of TAPSE/sPAP in patients hospitalized for acute heart failure.

AIMS: Tricuspid annular plane systolic excursion over systolic pulmonary artery pressure (TAPSE/sPAP) assessed by echocardiography appears to be a good non-invasive approach for right ventricular to pulmonary artery coupling assessment. We aimed to assess the in-hospital prognostic value of TAPSE/sPAP among patients hospitalized for acute heart failure (AHF). METHODS AND RESULTS: In total, 333 consecutive patients (mean age 68 ± 14 years, 70% of male, mean left ventricular ejection fraction 44 ± 16%) were hospitalized for AHF across 39 French cardiology departments, with TAPSE/sPAP measured by echocardiography within the first 24 h of hospitalization were included in this prospective study. The primary outcome was in-hospital major adverse cardiovascular events (MACEs) defined as all-cause death, resuscitated cardiac arrest or cardiogenic shock and occurred in 50 (15%) patients. Using receiver operating characteristic curve analysis, the best TAPSE/sPAP threshold for in-hospital MACEs was 0.40 mm/mmHg. TAPSE/sPAP < 0.40 mm/mmHg was independently associated with in-hospital MACEs, even after adjustment with comorbidities [odds ratio (OR): 3.75, 95% CI (1.87-7.93), P < 0.001], clinical severity [OR: 2.80, 95% CI (1.36-5.95), P = 0.006]. Using a 1:1 propensity-matched population, TAPSE/sPAP ratio < 0.40 was associated with a higher rate of in-hospital MACEs [OR: 2.98, 95% CI (1.53-6.12), P = 0.002]. After adjustment, TAPSE/sPAP < 0.40 showed the best improvement in model discrimination and reclassification above traditional prognostic factors (C-statistic improvement: 0.05; χ2 improvement: 14.4; likelihood-ratio test P < 0.001). These results were consistent in an external validation cohort of 133 patients. CONCLUSION: TAPSE/sPAP < 0.40 mm/mmHg assessed by an early echocardiography during an AHF episode is independently associated with in-hospital MACEs suggesting enhanced close monitoring and strengthened heart failure-specific care in these patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05063097.

Profile of patients hospitalized in intensive cardiac care units in France: ADDICT-ICCU registry.

BACKGROUND: Intensive cardiac care units (ICCU) were initially developed to monitor ventricular arrhythmias after myocardial infarction. In recent decades, ICCU have diversified their activities. AIM: To determine the type of patients hospitalized in ICCU in France. METHODS: We analysed the characteristics of patients enrolled in the ADDICT-ICCU registry (NCT05063097), a prospective study of consecutive patients admitted to ICCU in 39 centres throughout France from 7th-22nd April 2021. In-hospital major adverse events (MAE) (death, resuscitated cardiac arrest and cardiogenic shock) were recorded. RESULTS: Among 1499 patients (median age 65 [interquartile range 54-74] years, 69.6% male, 21.7% diabetes mellitus, 64.7% current or previous smokers), 34.9% had a history of coronary artery disease, 11.7% atrial fibrillation and 5.2% cardiomyopathy. The most frequent reason for admission to ICCU was acute coronary syndromes (ACS; 51.5%), acute heart failure (AHF; 14.1%) and unexplained chest pain (6.8%). An invasive procedure was performed in 36.2%. "Advanced" ICCU therapies were required for 19.9% of patients (intravenous diuretics 18.4%, non-invasive ventilation 6.1%, inotropic drugs 2.3%). No invasive procedures or advanced therapies were required in 44.1%. Cardiac computed tomography or magnetic resonance imaging was carried out in 12.3% of patients. The median length of ICCU hospitalization was 2.0 (interquartile range 1.0-4.0) days. The mean rate of MAE was 4.5%, and was highest in patients with AHF (10.4%). CONCLUSIONS: ACS remains the main cause of admissions to ICCU, with most having a low rate of in-hospital MAE. Most patients experience a brief stay in ICCU before being discharged home. AHF is associated with highest death rate and with higher resource consumption.

Carbon monoxide and prognosis in smokers hospitalised with acute cardiac events: a multicentre, prospective cohort study.

Background: Smoking cigarettes produces carbon monoxide (CO), which can reduce the oxygen-carrying capacity of the blood. We aimed to determine whether elevated expiratory CO levels would be associated with a worse prognosis in smokers presenting with acute cardiac events. Methods: From 7 to 22 April 2021, expiratory CO levels were measured in a prospective registry including all consecutive patients admitted for acute cardiac event in 39 centres throughout France. The primary outcome was 1-year all-cause death. Initial in-hospital major adverse cardiac events (MAE; death, resuscitated cardiac arrest and cardiogenic shock) were also analysed. The study was registered at ClinicalTrials.gov (NCT05063097). Findings: Among 1379 patients (63 ± 15 years, 70% men), 368 (27%) were active smokers. Expiratory CO levels were significantly raised in active smokers compared to non-smokers. A CO level >11 parts per million (ppm) found in 94 (25.5%) smokers was associated with a significant increase in death (14.9% for CO > 11 ppm vs. 2.9% for CO ≤ 11 ppm; p < 0.001). Similar results were found after adjustment for comorbidities (hazard ratio [HR] [95% confidence interval (CI)]): 5.92 [2.43-14.38]) or parameters of in-hospital severity (HR 6.09, 95% CI [2.51-14.80]) and propensity score matching (HR 7.46, 95% CI [1.70-32.8]). CO > 11 ppm was associated with a significant increase in MAE in smokers during initial hospitalisation after adjustment for comorbidities (odds ratio [OR] 15.75, 95% CI [5.56-44.60]) or parameters of in-hospital severity (OR 10.67, 95% CI [4.06-28.04]). In the overall population, CO > 11 ppm but not smoking was associated with an increased rate of all-cause death (HR 4.03, 95% CI [2.33-6.98] and 1.66 [0.96-2.85] respectively). Interpretation: Elevated CO level is independently associated with a 6-fold increase in 1-year death and 10-fold in-hospital MAE in smokers hospitalized for acute cardiac events. Funding: Grant from Fondation Coeur & Recherche.

Impact of Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Replacement.

BACKGROUND: Data on the long-term impact of prosthesis-patient mismatch (PPM) on outcomes after transcatheter aortic valve replacement (TAVR) remain sparse. We therefore aimed to investigate the incidence, predictive factors, and long-term prognostic impact of PPM on bioprosthesis durability and mortality. METHODS: This was a single-centre retrospective study including 2117 patients who underwent TAVR for aortic stenosis from 2002 to 2022. Moderate PPM was defined by indexed effective orifice area (iEOA) > 0.65 and ≤ 0.85 cm2/m2 (> 0.55 and ≤ 0.70 cm2/m2 if BMI ≥ 30 kg/m2) and severe PPM by an iEOA ≤ 0.65 cm2/m2 (≤ 0.55 cm2/m2 If BMI ≥ 30 kg/m2). RESULTS: There were 351 patients (16.6%) with PPM, including 39 patients (1.8%) with severe PPM and 312 patients (14.7%) with moderate PPM. The mean follow-up duration was 31.2 ± 26.5 months. Factors independently associated with the occurrence of PPM were body surface area (odds ratio [OR] 3.32, 95% confidence interval [CI] 1.32-8.35; P = 0.01), valve-in-valve TAVR (OR 6.12, 95% CI 2.29-16.08; P < 0.001), small annulus (OR 2.42, 95% CI 1.41-4.07; P = 0.001), and the use of a balloon-expandable valve (OR 4.17, 95% CI 2.17-8.33; P < 0.001). PPM was associated with increased risk of mortality (hazard ratio [HR] 1.3, 95% CI 1.1-1.5, P = 0.004) and valve thrombosis (HR 4.2, 95% CI 1.4-12.6, P = 0.01), and a trend towards increased risk of structural valve deterioration (HR 1.7, 95% CI 0.9-2.9; P = 0.08). CONCLUSIONS: The results of this study suggest that PPM has a negative long-term impact on outcomes after TAVR. These findings emphasise the importance of preventing PPM.

Real-world evidence to advance knowledge in pulmonary hypertension: Status, challenges, and opportunities. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative's Real-world Evidence Working Group.

This manuscript on real-world evidence (RWE) in pulmonary hypertension (PH) incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative Real-World Evidence Working Group. We aim to strengthen the research community's understanding of RWE in PH to facilitate clinical research advances and ultimately improve patient care. Herein, we review real-world data (RWD) sources, discuss challenges and opportunities when using RWD sources to study PH populations, and identify resources needed to support the generation of meaningful RWE for the global PH community.

Prevalence and impact of recreational drug use in patients with acute cardiovascular events.

OBJECTIVE: While recreational drug use is a risk factor for cardiovascular events, its exact prevalence and prognostic impact in patients admitted for these events are not established. We aimed to assess the prevalence of recreational drug use and its association with in-hospital major adverse events (MAEs) in patients admitted to intensive cardiac care units (ICCU). METHODS: In the Addiction in Intensive Cardiac Care Units (ADDICT-ICCU) study, systematic screening for recreational drugs was performed by prospective urinary testing all patients admitted to ICCU in 39 French centres from 7 to 22 April 2021. The primary outcome was prevalence of recreational drug detection. In-hospital MAEs were defined by death, resuscitated cardiac arrest, or haemodynamic shock. RESULTS: Of 1499 consecutive patients (63±15 years, 70% male), 161 (11%) had a positive test for recreational drugs (cannabis 9.1%, opioids 2.1%, cocaine 1.7%, amphetamines 0.7%, 3,4-methylenedioxymethamphetamine (MDMA) 0.6%). Only 57% of these patients declared recreational drug use. Patients who used recreational drugs exhibited a higher MAE rate than others (13% vs 3%, respectively, p<0.001). Recreational drugs were associated with a higher rate of in-hospital MAEs after adjustment for comorbidities (OR 8.84, 95% CI 4.68 to 16.7, p<0.001). After adjustment, cannabis, cocaine, and MDMA, assessed separately, were independently associated with in-hospital MAEs. Multiple drug detection was frequent (28% of positive patients) and associated with an even higher incidence of MAEs (OR 12.7, 95% CI 4.80 to 35.6, p<0.001). CONCLUSION: The prevalence of recreational drug use in patients hospitalised in ICCU was 11%. Recreational drug detection was independently associated with worse in-hospital outcomes. CLINICAL TRIAL REGISTRATION: NCT05063097.

Upgrading extra corporeal life support to ECMELLA using Impella 5.0 in rescued INTERMACS 1 patients, lactate level matters!

Background: Venoarterial extra corporeal life support (ECLS) is the treatment of choice of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) class 1 patients, but left ventricle (LV) overload is a complication of ECLS. Unloading the LV by adding Impella 5.0 to ECLS in Impella used in combination with venoarterial extracorporeal membrane oxygenation (ECMELLA) configuration is recommended only in patients with acceptable prognosis. We investigated whether serum lactate level, a simple biological parameter, could be used as a marker to select candidates for bridging from ECLS to ECMELLA. Methods: Forty-one consecutive INTERMACS 1 patients under ECLS were upgraded to ECMELLA using Impella 5.0 pump implantation to unload the LV and were followed-up for 30 days. Demographic, clinical, imaging, and biological parameters were collected. Results: The time between ECLS and Impella 5.0 pump implantation was 9 [0-30] hours. Among these 41 patients, 25 died 6±6 days after implantation. They were older (53±12 vs. 43±12 years, P=0.01) with acute coronary syndrome as the primary etiology (64% vs. 13%, P=0.0007). In univariate analysis, patients who died exhibited a lower mean arterial pressure (74±17 vs. 89±9 mmHg, P=0.01), a higher level of troponin (24,000±38,000 vs. 3,500±5,000 mg/dL, P=0.048), a higher level of serum lactate (8.3±7.4 vs. 4.2±3.8 mmol/L, P=0.05) and more frequent cardiac arrest at admission (80% vs. 25%, P=0.03). In multivariate Cox regression analysis, a serum lactate level of >7.9 mmol/L (P=0.008) was found to be an independent predictor of mortality. Conclusions: In INTERMACS 1 patients who require urgent ECLS for restoring hemodynamics and organ perfusion, an upgrade from ECLS to ECMELLA is relevant if the serum lactate level is ≤7.9 mmol/L.

Do Patients With Low-Risk Pulmonary Arterial Hypertension Really Benefit From Upfront Combination Therapy?: Insight From the AMBITION Trial.

BACKGROUND: Based on results of the Ambrisentan and Tadalafil in Patients with Pulmonary Arterial Hypertension (AMBITION) trial, upfront combination therapy is recommended for treatment-naive patients with low-risk pulmonary arterial hypertension (PAH). However, conflicting data exist whether adopting this treatment strategy in this risk group is beneficial or well tolerated. RESEARCH QUESTION: Do patients with low-risk PAH really benefit from upfront combination therapy? STUDY DESIGN AND METHODS: Using the data from the original AMBITION trial, patients with PAH were classified as low, intermediate, or high risk using the Registry to Evaluate Early and Long-term PAH Disease Management 2.0 (REVEAL 2.0) score and the Pulmonary Hypertension Outcomes and Risk Assessment (PHORA) tool. The primary end point was time to clinical worsening (including death, hospitalization for PAH worsening, and disease progression) censored at 1- and 3-year post-enrollment. Side effects that led to withdrawal of treatment were also considered. RESULTS: Patients with low-risk PAH categorized by REVEAL 2.0 and PHORA did not see a statistically significant benefit of upfront combination therapy vs monotherapy for time to clinical worsening at 1 and 3 years' post-enrollment using Cox proportional analysis (3-year hazard ratio of 0.40 [95% CI, 0.15-1.06; P = .07] and 0.55 [95% CI, 0.26-1.18; P = .12] for REVEAL 2.0 and PHORA, respectively) or considering time to clinical worsening or side effects (3-year hazard ratio of 0.75 [95% CI, 0.39-1.47; P = .4] and 0.87 [95% CI, 0.49-1.54; P = .63] for REVEAL 2.0 and PHORA). Patients with low-risk PAH on upfront combination therapy experienced a higher but not significant incidence of side effects using REVEAL 2.0 and PHORA. In contrast, patients at intermediate or high risk saw a statistically significant benefit of upfront combination therapy considering each of the end points regardless of side effects. INTERPRETATION: This analysis suggests that perhaps some patients with low-risk PAH should be further stratified using other modalities prior to committing to upfront combination therapy, especially when the occurrence of side effects is considered. Further prospective data are needed to validate this hypothesis prior to changes in current guideline directed therapy are contemplated.