Pulmonary hypertension associated with rheumatic diseases: baseline characteristics from the Korean registry

The prognosis and management of reclassified systemic lupus erythematosus associated pulmonary arterial hypertension according to 2022 ESC/ERS guidelines

BACKGROUND AND AIMS

The 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) guideline has recently revised the hemodynamic definition of pulmonary arterial hypertension. However, there is currently limited research on the prognosis and treatment of system lupus erythematosus-associated pulmonary arterial hypertension (SLE-PAH) patients that have been reclassified by the new hemodynamic definition. This study aims to analyze the prognosis of newly reclassified SLE-PAH patients and provide recommendations for the management strategy.

METHODS

This retrospective study analyzed records of 236 SLE-PAH patients who visited Peking Union Medical College Hospital (PUMCH) from 2011 to 2023, among whom 22 patients were reclassified into mild SLE-PAH (mean pulmonary arterial pressure (mPAP) of 21-24 mmHg, pulmonary vascular resistance (PVR) of 2-3 WU, and PAWP ≤ 15 mmHg) according to the guidelines and 14 were defined as unclassified SLE-PAH patients (mPAP 21-24 mmHg and PVR ≤ 2 WU). The prognosis was compared among mild SLE-PAH, unclassified SLE-PH, and conventional SLE-PAH patients (mPAP ≥ 25 mmHg and PVR > 3WU). Besides, the effectiveness of pulmonary arterial hypertension (PAH)-specific therapy was evaluated in mild SLE-PAH patients.

RESULTS

Those mild SLE-PAH patients had significantly longer progression-free time than the conventional SLE-PAH patients. Among the mild SLE-PAH patients, 4 did not receive PAH-specific therapy and had a similar prognosis as patients not receiving specific therapy.

CONCLUSIONS

This study supports the revised hemodynamic definition of SLE-PAH in the 2022 ESC/ERS guideline. Those mild and unclassified SLE-PH patients had a better prognosis, demonstrating the possibility and significance of early diagnosis and intervention for SLE-PAH. This study also proposed a hypothesis that IIT against SLE might be sufficient for those reclassified SLE-PAH patients.

Diagnostic value of combined FVC%/DLCO% and echocardiography in connective tissue disorder‑associated pulmonary hypertension

The main objective of the present study was to investigate whether forced vital capacity (FVC)%/diffusing capacity of the lungs for carbon monoxide (DLCO)% can be used to predict the presence of pulmonary hypertension (PH) in connective tissue disorders (CTDs). For this purpose, a total of 53 individuals who were diagnosed with CTDs and had undergone right heart catheterization between July, 2019 and July, 2022 were included in the present study. Based on the mean pulmonary artery pressure (mPAP) measured during right heart catheterization, the participants were divided into the PH and non-PH groups. The differences in demographic characteristics, including sex, age, body mass index, smoking index, FVC%/DLCO% and pulmonary artery systolic pressure (PASP) were determined by echocardiography; moreover, the 6-min walk distance, plasma brain natriuretic peptide (BNP) levels, white blood cell count, red blood cell distribution width, erythrocyte sedimentation rate and C-reactive protein levels were compared between the two groups to identify independent predictors of PH. The independent predictors were subsequently evaluated for their correlation with mPAP to assess their predictive value for PH. FVC%/DLCO%, echocardiographic PASP, and plasma BNP levels were identified as independent predictors of PH. FVC%/DLCO% and echocardiographic PASP exhibited a significant correlation with mPAP, while the correlation between plasma BNP and mPAP levels was not statistically significant. The area under the curve (AUC) value for FVC%/DLCO% alone in predicting PH was 0.791, with an optimal diagnostic threshold of 1.35, a sensitivity of 0.794 and a specificity of 0.789. The AUC for echocardiographic PASP alone in predicting PH was 0.783, with an optimal diagnostic threshold of 39.5 mmHg, a sensitivity of 0.794 and a specificity of 0.684. When combined, the AUC of the two factors in predicting PH was 0.872, with a sensitivity of 0.941 and a specificity of 0.684. Collectively, the data of the present study indicate that FVC%/DLCO% may be used as a predictive factor for CTD-PH, and its combined application with echocardiographic PASP measurement may provide additional evidence for the clinical diagnosis of CTD-PH.

Pulmonary hypertension in connective tissue diseases: epidemiology, pathogenesis, and treatment

Pulmonary hypertension (PH) is a clinical condition characterized by increased pulmonary arterial pressure arising from a heterogeneous range of diseases that has a deteriorating effect on the quality of life and may cause early mortality if left untreated. Connective tissue disorders (CTD)-associated PH is the second most common cause of pulmonary arterial hypertension (PAH), after the idiopathic form, categorized as group I. Systemic scleroderma (SSc) accounts for 75% of CTD-associated PH cases. Although SSc ranks first place for CTD-associated PH, SSc is followed by systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD), having a lesser frequency of PH occurrence, while it occurs as a rare complication in cases with rheumatoid arthritis (RA) and inflammatory myositis. PH may also occur during non-SSc CTDs and even other rheumatic diseases, including Behcet's disease and adult-onset Still's disease, albeit to a lesser extent. The prognosis of CTD-associated PH is worse than the other forms of PH. Although, as in idiopathic pulmonary arterial hypertension (IPAH), the mechanism of CTD-related PH is associated with an increase in vasoconstrictors like endothelin-1 and a decrease in vasodilators like prostacyclin and nitric oxide production, inflammation, and autoimmune mechanisms also play a role in the development and progression of PH. This may lead to the involvement of more than one mechanism in CTD-associated PH. Knowing which mechanism is dominant is very important in determining the treatment option. This review will primarily focus on the epidemiology, risk factors, and prognosis of PH that develops during rheumatic diseases; the pathogenesis and treatment will be briefly mentioned in light of the newly published guidelines. Key Points • Pulmonary arterial hypertension (PAH) associated with connective tissue disease (CTD) in Western countries is the second most common type of PAH after idiopathic PAH (IPAH). • CTD-PH can be seen most often in systemic scleroderma (SSc), less in systemic lupus erythematosus (SLE), mixed CTD (MCTD), and rarely in other CTDs. • While current guidelines recommend annual transthoracic echocardiography as a screening test for asymptomatic SSc patients, screening for PH is not advised in the absence of symptoms suggestive of PH in other CTDs. • CTD-PH treatment can be divided into specific vasodilator PH treatments and immunosuppressive therapy. Current treatment guidelines recommend the same treatment algorithm for patients with CTD-associated PH as for patients with IPAH. Several case series have shown the beneficial effect of immunosuppressive agents in patients with SLE-PH and MCTD-PH.

Pharmacological management of connective tissue disease-associated pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a severe, progressive pulmonary vasculopathy (Group 1 Pulmonary Hypertension (PH)) that complicates the course of many connective tissue diseases (CTD). Detailed testing is required to differentiate PAH from other types of PH caused by CTD such as left heart disease (Group 2 PH), pulmonary parenchymal disease (Group 3 PH), and chronic thromboembolic pulmonary hypertension (Group 4 PH). PAH is most frequently seen in systemic sclerosis but can also be seen with systemic lupus erythematosus, mixed CTD, and primary Sjogren's syndrome.

AREAS COVERED

This review discusses the epidemiology of CTD-associated PAH, outlines the complex diagnosis approach, and finishes with an in-depth discussion on the current treatment paradigm. Focus is placed on challenges faced in the treatment of CTD-associated PAH, (decreased efficacy and poorer tolerance of pharmacological therapies) and includes a discussion on the future investigational treatments.

EXPERT OPINION

Despite significant advances over the past decades with more aggressive treatment algorithms, CTD-associated PAH patients continue to have poorer survival compared to those with idiopathic PAH. This review highlights factors leading to disparate outcomes compared to other forms of PAH, and discusses on further improvements that may increase quality of life and survival for CTD-associated PAH patients.

Connective Tissue Disease-Associated Pulmonary Arterial Hypertension in Southern Taiwan: A Single-Center 10-Year Longitudinal Observation Cohort

Background: Pulmonary arterial hypertension (PAH) is a life-threatening disease with different etiologies and outcomes. We aimed to explore differences in clinical features and outcomes of idiopathic PAH (iPAH) and connective tissue disease-related PAH (CTD-PAH) in Taiwanese patients and determine risk factors for mortality. Methods: We retrospectively reviewed the medical records of patients with right-sided heart catheterization-diagnosed PAH between January 2005 and December 2015. The iPAH (n = 31) and CTD-PAH (n = 14) patients were enrolled and followed until December 31, 2019. Between-group comparisons were conducted. Potential predictors of the mortality of PAH were determined using the Cox proportional hazard regression model. Results: CTD-PAH patients had higher levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and lower predicted diffusing capacity of carbon monoxide (DLCO) than iPAH patients. The mortality rates were similar between CTD-PAH and iPAH (21.4% vs. 22.6%, p = 0.99). A mean pulmonary arterial pressure (mPAP) > 46 mmHg was a predictor of PAH-induced mortality (adjusted hazard ratio 21.8, 95% confidence interval 2.32–204.8). Conclusions: A higher mPAP level, but not underlying CTDs, imposed a significantly increased risk of mortality to patients with PAH.

Outcomes and Risk Factors of Systolic Pulmonary Artery Pressure Progression in Patients with Systemic Rheumatic Diseases: Follow-up Results from a Korean Registry

Objectives

This study aims to investigate the outcomes and risk factors associated with the progression of systolic pulmonary artery pressure (sPAP) in patients with systemic rheumatic diseases.

Patients and methods

A total of 532 patients (73 males, 459 females; median age 49 years; interquartile range (IQR), 36 to 62 years) registered with the Registry of Pulmonary Hypertension Associated with Rheumatic Diseases were included. Mortality curves were constructed using the Kaplan- Meier method and comparisons were performed using the log-rank test. A paired t-test was performed to evaluate the patients with markedly elevated sPAP between baseline and follow-up.

Results

The average follow-up duration was 31 months (IQR, 9 to 60 months). Of the patients, 196 had follow-up echocardiographs at least one year later. We defined the sPAP over 60 mmHg as markedly elevated. Patients in the increased sPAP above 60 mmHg at follow-up and persistently markedly elevated sPAP were associated with worse outcomes in all-cause mortality and pulmonary arterial hypertension-related mortality (p<0.001). In patients with systemic sclerosis, the majority of patients remained static within their pressure group or rose progressively: the patients with markedly elevated sPAP at follow-up were higher than those at baseline (32% versus 15%, p<0.01). In patients with mixed connective tissue disease (MCTD) or rheumatoid arthritis (RA), the majority of patients remained static within their pressure group or gradually improved: the patients with markedly elevated sPAP at follow-up were lower than those at baseline (RA=14% versus 29%, MCTD=5% versus 16%, p<0.05).

Conclusion

Persistently high sPAP or increase of sPAP over 60 mmHg at follow-up was associated with increased mortality. There were some differences in the progression of sPAP according to the underlying rheumatic diseases.

Pulmonary arterial hypertension associated with primary Sjögren's syndrome: a multicentre cohort study from China

OBJECTIVES

Primary Sjögren's syndrome (pSS) is an important cause of pulmonary arterial hypertension (PAH), which remains insufficiently studied and needs attention. This study aimed to investigate the clinical characteristics, risk factors, prognosis and risk assessment of pSS-PAH.

METHODS

We established a multicentre cohort of pSS-PAH diagnosed by right heart catheterisation. The case-control study was conducted with pSS-non-PAH patients as a control group to identify the risk factors for PAH. In the cohort study, survival was calculated, and risk assessment was performed at both baseline and follow-up visits.

RESULTS

In total, 103 patients with pSS-PAH were enrolled, with 526 pSS-non-PAH patients as controls. The presence of anti-SSB (p<0.001, OR 4.095) and anti-U1RNP antibodies (p<0.001, OR 29.518), the age of pSS onset (p<0.001, OR 0.651) and the positivity of corneal staining (p=0.003, OR 0.409) were identified as independent risk factors for PAH. The 1-, 3- and 5-year survival rates were 94.0%, 88.8% and 79.0%, respectively. Cardiac index (p=0.010, hazard ratio (HR) 0.161), pulmonary vascular resistance (p=0.016, HR 1.105) and Sjögren's syndrome disease damage index (p=0.006, HR 1.570) were identified as potential predictors of death in pSS-PAH. Long-term outcomes were improved in patients in the low-risk category at baseline (p=0.002) and follow-up (p<0.0001).

CONCLUSION

The routine screening of PAH is suggested in pSS patients with early onset and positivity for anti-SSB or anti-U1RNP antibodies. Patient prognosis might be improved by improving reserved cardiopulmonary function, by achieving a damage-free state and especially by achieving low-risk category, which supports the treat-to-target strategy for pSS-PAH.

Long-term prognosis of patients with systemic lupus erythematosus-associated pulmonary arterial hypertension: CSTAR-PAH cohort study

This study aimed to identify the long-term clinical outcomes and prognostic factors of patients with systemic lupus erythematosus (SLE)-associated pulmonary arterial hypertension (PAH) confirmed by right heart catheterisation.

A multicentre prospective cohort of SLE-associated PAH was established. Baseline and follow-up records were collected. The primary end-point was death. The secondary exploratory end-point was treatment goal achievement (TGA), defined as an integrated outcome.

In total, 310 patients were enrolled from 14 PAH centres. The 1-, 3- and 5-year survival rates were 92.1%, 84.8% and 72.9%, respectively. The 1-, 3- and 5-year TGA rates were 31.5%, 53.6% and 62.7%, respectively. Baseline serositis, 6-min walking distance >380 m and cardiac index ≥2.5 L·min−1·m−2 were identified as independent prognostic factors of TGA. Patients with baseline serositis were more likely to reach TGA after intensive immunosuppressive therapy. TGA was identified as a positive predictor of survival in patients with SLE-associated PAH.

TGA was associated with long-term survival, which supports the treat-to-target strategy in SLE-associated PAH. Baseline heart function predicted both survival and treatment goal achievement in patients with SLE-associated PAH. Patients with serositis at baseline tended to benefit from intensive immunosuppressive therapy and have a better clinical outcome.

Factors associated with development and mortality of pulmonary hypertension in systemic lupus erythematosus patients

Objectives

This study aims to identify the factors associated with the development and mortality of pulmonary hypertension (PH) in systemic lupus erythematosus (SLE) patients.

Methods

We conducted a prospective study of SLE patients in a single tertiary center. PH was defined as a systolic pulmonary arterial pressure ≥30 mmHg on transthoracic echocardiography. We assessed potential associated factors contributing to the development and mortality of PH in SLE patients.

Results

Of 1110 patients with SLE, 48 patients were identified to have PH. Multivariable analysis indicated that pleuritis or pericarditis (odds ratio (OR) = 4.62), anti-RNP antibody (OR = 2.42), interstitial lung disease (ILD) (OR = 8.34) and cerebro-cardiovascular disease (OR = 13.37) were independently associated with the development of PH in SLE. Subgroup analysis among patients with PH demonstrated that there were no statistically significant factors associated with PH mortality in SLE.

Conclusions

The prevalence of PH was 4.3% in our cohort. There were significant associations with pleuritis or pericarditis, anti-RNP antibody, ILD, and cerebro-cardiovascular disease in SLE, which may contribute to the development of PH. However, there were no statistically significant factors associated with PH mortality in SLE.

Mixed connective tissue disease-enigma variations?

In 1972, Sharp et al. described a new autoimmune rheumatic disease that they called MCTD, characterized by overlapping features of SSc, SLE, PM/DM, high levels of anti-U1snRNP and low steroid requirements with good prognosis. MCTD was proposed as a distinct disease. However, soon after the original description, questions about the existence of such a syndrome as well as disputes over the features initially described began to surface. The conundrum of whether MCTD is a distinct disease entity remains controversial. We undertook a literature review, focusing on the articles reporting new data about MCTD published in the last decade, to determine whether any new observations help to answer the conundrum of MCTD. After reviewing recent data, we question whether the term MCTD is appropriately retained, preferring to use the term undifferentiated autoimmune rheumatic disease.

Transition to routine use of venoarterial extracorporeal oxygenation during lung transplantation could improve early outcomes

BACKGROUND

The study objective was to compare the outcomes of intraoperative routine use of venoarterial (VA) extracorporeal membrane oxygenation (ECMO) versus selective use of cardiopulmonary bypass (CPB).

METHODS

Between January 2010 and February 2013, 41 lung transplantations (LTx) were performed, and CPB was used as a primary cardiopulmonary support modality by selective basis (group A). Between March 2013 and December 2014, 41 LTx were performed, and ECMO was used routinely (group B). The two groups were compared retrospectively.

RESULTS

The operative time was significantly longer in group A (group A, 458 min; group B, 420 min; P=0.041). Postoperatively, patients in group B had less fresh frozen plasma (FFP) transfusion (P=0.030). Complications were not different between the two groups. The 30- and 90-day survival rates were better in group B (30-day survival: group A, 75.6%; group B, 95.1%, P=0.012; 90-day survival: group A, 68.3%; group B, 87.8%, P=0.033). The 1-year survival showed better trends in group B, but it was not significant. Forced vital capacity (FVC) at 1, 3, and 6 months after LTx was better in group B than in group A (1 month: group A, 43.8%; group B, 52.9%, P=0.043; 3 months: group A, 45.5%; group B, 59.0%, P=0.005; 6 months: group A, 51.5%; group B, 65.2%, P=0.020). Forced expiratory volume in 1 second (FEV1) at 3 months after LTx was better in patients in group B than that in patient in group A (group A, 53.3%; group B, 67.5%, P=0.017).

CONCLUSIONS

Routine use of ECMO during LTx could improve early outcome and postoperative lung function without increased extracorporeal-related complication such as vascular and neurologic complications.

Baseline Characteristics and Risk Factors of Pulmonary Arterial Hypertension in Systemic Lupus Erythematosus Patients

Peking Union Medical College Hospital (PUMCH) has started a single-center right heart catheterization (RHC)-based pulmonary arterial hypertension (PAH) study in systemic lupus erythematosus (SLE) since 2006. The baseline characteristics of these patients were described and the risk factor for PAH in lupus was identified.The demographic, clinical, laboratory, and treatment characteristics of SLE patients with PAH when they were registered were collected as the baseline data. A case-control study was conducted by taking the admitted SLE-non-PAH patients adjusted for age and gender in a 4:1 ratio during the same period as the controls. The associated variables were examined by binary multivariate logistic regression analysis to identify possible risk factors. A total of 111 RHC-confirmed SLE-PAH patients were enrolled, with the onset age of 34.6 ± 8.6 years old and the average SLE duration of 5 years. RHC revealed mPAP as 46.4 ± 11.4 mm Hg, CI as 2.7 ± 0.8 L/min × m, and PVR as 10.5 ± 4.8 WU. 46% of patients were WHO Fc I-II. All patients were treated with immunosuppressive agents and 65% patients had PAH-targeted therapy. The case-control study had confirmed 2 independent risk factors previously published: pericardial effusion (OR = 21.290, P < 0.001) and anti-RNP antibody (OR = 12.399, P < 0.001). Meanwhile, 6 independent variables were discovered: baseline SLE duration (OR = 1.118, P = 0.007), interstitial lung disease (OR = 17.027, P < 0.001=, without acute rash (OR = 3.258, P = 0.019), anti-SSA antibody (OR = 4.836, P = 0.004), SLEDAI≤9 (OR = 26.426, P < 0.001), ESR≤20 mm/h (OR = 12.068, P < 0.001), and uric acid > 357 μmol/L (OR = 9.666, P < 0.001) to be associated with PAH in SLE patients.The PUMCH study has shown that SLE patients complicated with PAH are usually earlier diagnosed and have less disease severity than patients without PAH. The immunosuppressive therapy rate and the PAH target therapy rate were high, which is consistent with reports from Western countries. This study has confirmed that pericardial effusion and positive anti-RNP antibody are risk factors for SLE-associated PAH. Long SLE disease duration, the presence of interstitial lung disease, without acute skin rash, positive anti-SSA antibody, low SLEDAI and ESR, and high uric acid levels are also associated with PAH in SLE patients.

The dynamic evolution of rheumatology in Korea

Rheumatology was first recognized as a distinct clinical specialty in Korea just 35 years ago. Young professors who were trained in rheumatology in the USA and afterwards returned to Korea contributed substantially to advances in rheumatology clinical practice, educational programmes and research activities. They also established the Korean Rheumatism Association, later renamed the Korean College of Rheumatology. These young rheumatologists had a major role not only in raising the level of clinical and scientific activities, but also in promoting academic exchanges around the Asia-Pacific region, the USA and Europe. Subsequently, Korea's rapid economic growth and high education level enabled rheumatology to advance rapidly. Today, continued efforts are required to raise the standard of clinical and basic research, to optimize clinical practice with regard to new biologic agents, to exploit personalized and targeted therapies for the rheumatic diseases, and to meet the medical demands of Korea's ageing society.

Baseline Characteristics of the Korean Registry of Pulmonary Arterial Hypertension

Despite recent advances in understanding of the pathobiology and targeted treatments of pulmonary arterial hypertension (PAH), epidemiologic data from large populations have been limited to western countries. The aim of the Korean Registry of Pulmonary Arterial Hypertension (KORPAH) was to examine the epidemiology and prognosis of Korean patients with PAH. KORPAH was designed as a nationwide, multicenter, prospective data collection using an internet webserver from September 2008 to December 2011. A total of 625 patients were enrolled. The patients' mean age was 47.6 ± 15.7 yr, and 503 (80.5%) were women. The diagnostic methods included right heart catheterization (n = 249, 39.8%) and Doppler echocardiography (n = 376, 60.2%). The etiologies, in order of frequency, were connective tissue disease (CTD), congenital heart disease, and idiopathic PAH (IPAH) (49.8%, 25.4%, and 23.2%, respectively). Patients with WHO functional class III or IV at diagnosis were 43.4%. In total, 380 (60.8%) patients received a single PAH-specific treatment at the time of enrollment, but only 72 (18.9%) patients received combination therapy. Incident cases during the registry represented 297 patients; therefore, the incidence rate of PAH was 1.9 patients/yr/million people. The 1st-, 2nd-, and 3rd-yr estimated survival rates were 90.8%, 87.8%, and 84.4%, respectively. Although Korean PAH patients exhibited similar age, gender, and survival rate compared with western registries, they showed relatively more CTD-PAH in the etiology and also systemic lupus erythematosus among CTD-PAH. The data suggest that earlier diagnosis and more specialized therapies should be needed to improve the survival of PAH patients.

Survival and prognostic factors in patients with connective tissue disease-associated pulmonary hypertension diagnosed by echocardiography: results from a Korean nationwide registry

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a major cause of mortality in connective tissue disease (CTD). The survival rates and mortality-predictive factors of a nationwide registry of Korean patients with CTD-PH measured by echocardiography were determined.

METHODS

Patients with CTD-PH were enrolled between April 2008 and December 2012. Hemodynamic parameters and clinical data (WHO-functional class [FC], organ involvement, laboratory tests and treatment agents) were recorded. Survival rates were calculated by using the Kaplan-Meier method. Mortality-associated factors were examined by Cox proportional hazards regression analysis.

RESULTS

In total, 174 incident PH cases (61 with systemic lupus erythematosus, 50 with systemic sclerosis, 10 with mixed CTD, 22 with rheumatoid arthritis (RA) and 31 with other CTDs) were diagnosed by Doppler echocardiography. Of these, 25 (14%) died during the 3.8 ± 2.7 year follow-up period after PH diagnosis. The 1- and 3-year survival rates were 90.7% and 87.3%, respectively. Compared to the other CTD-PHs, RA-PH had the lowest survival rates (56% 3 year survival; P = 0.022). Multiple regression analysis revealed that low diffusion capacity of carbon monoxide (DLCO), pleural effusion and diabetes mellitus were poor prognostic factors (P = 0.008, 0.04 and 0.009, respectively). Anti-UI-RNP (ribonucleoprotein) antibody positivity was protective (P = 0.022). In patients with WHO-FC III/IV, patients who received vasodilators had lower mortality than those who did not (P = 0.038).

CONCLUSIONS

In Korean patients with CTD-PH, the 3-year survival rate was 87%. Low diffusion capacity of carbon monoxide (DLCO), pleural effusion and diabetes mellitus were independent poor prognostic factors. Anti-UI-RNP antibody was protective. Prompt PAH-specific vasodilator therapy may improve the survival of patients with severe CTD-PH.

Connective tissue disease-associated pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by vascular remodeling of pulmonary arterioles that leads to increased pulmonary vascular resistance, right heart failure, and death. It is associated with connective tissue diseases, including systemic sclerosis, systemic lupus erythematosus, and mixed connective tissue disease. PAH is characterized by dyspnea on exertion and fatigue. Syncopal events suggest severe disease. Patients may present with signs of right heart failure. One- and 3-year survival rates are approximately 81% and 52%, respectively. Given the high prevalence and mortality, algorithms for screening are currently under investigation and will hopefully lead to earlier diagnosis and improved survival.

Epidemiology of pulmonary arterial hypertension

The epidemiology of pulmonary arterial hypertension (PAH) has changed over the last decade. Remarkable advances in understanding the pathobiology and clinical care required in PAH have resulted in improved quality of life and survival. Despite such important progress, the long-term rate of survival is still unacceptable. The epidemiology of PAH could not be easily generalized globally, due to the fact that nearly all of the present data has been gathered from Western, multicenter, prospective registries. There are potentially marked differences in PAH patients from Western and Eastern populations, and from developed and developing countries. Therefore, it is clear that more registry data will be needed to address novel questions emerging with improved knowledge of PAH.

Pulmonary hypertension in systemic lupus erythematosus

Systemic lupus erythematosus is associated with several forms of pulmonary hypertension. It can cause pulmonary hypertension through pulmonary thromboembolic disease, left heart disease and lung disease as well as causing an isolated pulmonary vasculopathy called pulmonary arterial hypertension. The true prevalence of pulmonary arterial hypertension in patients with lupus is not known but probably is no more than 1%. Currently, treatment for lupus-associated pulmonary arterial hypertension is with pulmonary vasodilators including phosphodiesterase-5 inhibitors, endothelin receptor antagonists and prostacyclin analogues, as it is for other causes of pulmonary arterial hypertension. Case series suggest there may be a special role for immunosuppression in this rare group of patients. We present two brief case histories and summarise our experience over 15 years. Prognosis is better in lupus-associated pulmonary arterial hypertension than in systemic sclerosis-associated pulmonary arterial hypertension, but unfortunately it remains a fatal condition in most patients.