Cardiopulmonary assessment of patients with systemic sclerosis for hematopoietic stem cell transplantation: recommendations from the European Society for Blood and Marrow Transplantation Autoimmune Diseases Working Party and collaborating partners

Systemic sclerosis (SSc) is a rare disabling autoimmune disease with a similar mortality to many cancers. Two randomized controlled trials of autologous hematopoietic stem cell transplantation (AHSCT) for SSc have shown significant improvement in organ function, quality of life and long-term survival compared to standard therapy. However, transplant-related mortality (TRM) ranged from 3-10% in patients undergoing HSCT. In SSc, the main cause of non-transplant and TRM is cardiac related. We therefore updated the previously published guidelines for cardiac evaluation, which should be performed in dedicated centers with expertize in HSCT for SSc. The current recommendations are based on pre-transplant cardiopulmonary evaluations combining pulmonary function tests, echocardiography, cardiac magnetic resonance imaging and invasive hemodynamic testing, initiated at Northwestern University (Chicago) and subsequently discussed and endorsed within the EBMT ADWP in 2016.

# Introduction
Systemic sclerosis (SSc) is a rare and heterogeneous autoimmune disease of unknown origin, with an incidence of 1 in 100 000.It is characterized by skin and visceral (lung, gastrointestinal, cardiovascular and renal) fibrosis secondary to excessive collagen deposition with a limited cutaneous (lc) and a diffuse cutaneous (dc) form. [bib_ref] 2013 classification criteria for systemic sclerosis: an American College of Rheumatology/European League..., Van Den Hoogen [/bib_ref] Rapidly progressive dc-SSc within the first 4 years of disease onset, observed in 10-20% of cases, is a life-threatening condition, with a 3-5 year survival between 50 and 70%, [bib_ref] Mortality in systemic sclerosis: an international meta-analysis of individual patient data, Ioannidis [/bib_ref] [bib_ref] Clinical prediction of 5-year survival in systemic sclerosis: validation of a simple..., Fransen [/bib_ref] the main cause of death being cardiac related. [bib_ref] Systemic sclerosis and the heart: current diagnosis and management, Desai [/bib_ref] [bib_ref] Trends in mortality in patients with systemic sclerosis over 40 years: a..., Elhai [/bib_ref] Numerous other factors have been reported to adversely reflect survival including extensive skin thickening (measured by the modified Rodnan skin score), 7 altered functional status (measured using the Self Health Assessment Questionnaire), altered renal function (presence of either hypertension, proteinuria, urinary casts having excluded non-SSc specific causes) or lung involvement (reflected in abnormal lung function or CT appearances) and older age at onset. [bib_ref] Systemic sclerosis: demographic, clinical, and serologic features and survival in 1012 Italian..., Ferri [/bib_ref] [bib_ref] Predicting mortality in systemic sclerosis: analysis of a cohort of 309 French..., Scussel-Lonzetti [/bib_ref] [bib_ref] Skin thickness progression rate: a predictor of mortality and early internal organ..., Domsic [/bib_ref] [bib_ref] Causes and risk factors for death in systemic sclerosis: a study from..., Tyndall [/bib_ref] Recently, more sensitive cardiac evaluations indicate that some of these adverse prognostic factors may be associated with markers of cardiac involvement. Pulmonary arterial hypertension (PAH) and pulmonary fibrosis [bib_ref] Survival and predictors of mortality in systemic sclerosis-associated pulmonary arterial hypertension: outcomes..., Chung [/bib_ref] [bib_ref] Value of systolic pulmonary arterial pressure as a prognostic factor of death..., Hachulla [/bib_ref] are also common causes of death. While hypoxemic respiratory failure may occur, the penultimate cause of death from PAH or interstitial lung disease (ILD) is often not suffocation per se, that is, inability to oxygenate blood, but rather cardiac failure in many patients.
Standard therapy with daily oral or monthly intravenous cyclophosphamide regimens in SSc has demonstrated only 1 limited benefit. [bib_ref] Effects of cyclophosphamide on pulmonary function in patients with scleroderma and interstitial..., Nannini [/bib_ref] [bib_ref] Effects of 1-year treatment with cyclophosphamide on outcomes at 2 years in..., Tashkin [/bib_ref] In contrast, early phase II trials [bib_ref] Autologous hematopoietic stem cell transplantation for autoimmune diseases: an observational study on..., Farge [/bib_ref] [bib_ref] Does ex vivo CD34 + positive selection influence outcome after autologous hematopoietic..., Oliveira [/bib_ref] and the randomized controlled ASSIST [bib_ref] Autologous non-myeloablative haemopoietic stem-cell transplantation compared with pulse cyclophosphamide once per month..., Burt [/bib_ref] followed by the large European ASTIS phase III trials in SSc [bib_ref] Autologous hematopoietic stem cell transplantation vs intravenous pulse cyclophosphamide in diffuse cutaneous..., Van Laar [/bib_ref] have shown that AHSCT using a high-dose cyclophosphamide regimen significantly improved forced vital capacity, decreased diseased-lung volume, and that SSc ILD might be partially reversed with continued improvement in lung function for at least 2 years after transplantation. [bib_ref] Autologous non-myeloablative haemopoietic stem-cell transplantation compared with pulse cyclophosphamide once per month..., Burt [/bib_ref] [bib_ref] Autologous hematopoietic stem cell transplantation vs intravenous pulse cyclophosphamide in diffuse cutaneous..., Van Laar [/bib_ref] [bib_ref] Autologous hematopoietic stem cell transplant in systemic sclerosis: quantitative high resolution computed..., Launay [/bib_ref] The presence of extensive lung disease or of specific cardiac involvement in patients undergoing AHSCT is associated with an increased transplant-related mortality (TRM), reflecting concerns that cardiac impairment or impaired respiratory function may directly or indirectly compromise cardiac function [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] and translate into high TRM due to inability to cope with complications. Due to direct cardiotoxicity of drugs, transplant-related fever, neutropenic infection and to saline overload during AHSCT, an extensive cardiac evaluation to exclude PAH and primary or secondary SSc-related cardiac involvement and constrictive pericarditis is essential to reduce the risk of TRM [bib_ref] Hematopoietic stem cell transplantation for systemic sclerosis: if you are confused, remember:..., Burt [/bib_ref] and to provide an acceptable risk-benefit ratio of AHSCT. [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] The aim of these guidelines is to summarize the current evidence-based practices and to make recommendations as to how TRM from AHSCT may be minimized through multiprofessional collaboration, careful patient selection, optimized treatment regimens and audit of outcomes. This cardiopulmonary guidelines process was initiated to update previous consensus 23 after 10 years of additional international experience, as initiated at Northwestern University (Chicago) [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] and subsequently discussed and endorsed within the European Society for Blood and Marrow Transplantation (EBMT)-Autoimmune Disease Working Party (ADWP) in 2016.

## Cardiopulmonary involvement in systemic sclerosis

## Cardiac complications
In early stages of disease, cardiac impairment is clinically underappreciated and often overlooked by standard echocardiographic reporting of gross wall motion abnormalities and left ventricular ejection fraction (LVEF). [bib_ref] Cardiac involvement in systemic sclerosis assessed by tissue-doppler echocardiography during routine care:..., Meune [/bib_ref] Relying on LVEF alone can be misleading, since SSc hearts may have a restrictive or constrictive physiology with relatively intact LVEF, but significant diastolic dysfunction. [bib_ref] Hematopoietic stem cell transplantation for systemic sclerosis: if you are confused, remember:..., Burt [/bib_ref] [bib_ref] Heart involvement in systemic sclerosis: evolving concept and diagnostic methodologies, Meune [/bib_ref] [bib_ref] Prevalence and factors associated with left ventricular dysfunction in the EULAR Scleroderma..., Allanore [/bib_ref] As the disease may be clinically silent for a long time, clinical studies only report a 10-61% prevalence of cardiac involvement by using transthoracic echocardiography (TTE) as a screening tool, [bib_ref] Systemic sclerosis and the heart: current diagnosis and management, Desai [/bib_ref] while it ranges between 50 and 81% in autopsybased studies of SSc. [bib_ref] Autopsy versus clinical findings in patients with systemic sclerosis in a case..., Sandmeier [/bib_ref] [bib_ref] Mortality and causes of death of 344 Danish patients with systemic sclerosis..., Jacobsen [/bib_ref] In the EUSTAR database concerning 7073 patients, [bib_ref] Prevalence and factors associated with left ventricular dysfunction in the EULAR Scleroderma..., Allanore [/bib_ref] LVEF was estimated by TTE using Simpson's method and the prevalence of LVEFo 55% was 5.4%. In contrast, a high prevalence of reduced left ventricle (LV) and/or right ventricle (RV) contractility in SSc patients despite a normal LVEF was detected when more sophisticated tools were used, such as tissue Doppler or cardiac magnetic resonance (CMR) imaging.
Ferri et al. [bib_ref] Systemic sclerosis: demographic, clinical, and serologic features and survival in 1012 Italian..., Ferri [/bib_ref] reported 36% of SSc deaths related to cardiac disease alone, and a recent literature search, 6 comprising a total of 12 829 SSc patients from 18 cohort studies, found that causes of death were 19.7% cardiac and 13.1% pulmonary hypertension, and the risk of death was increased in patients with cardiac involvement (hazard ratio (HR) 3.15)) and with PAH (HR 3.50). In daily clinical practice, cardiac evaluation of SSc patients is based on the results from clinical examination, electrocardiography (ECG) and TTE, and in the presence of palpitations or abnormalities on ECG, on 24 h Holter monitoring. B-type natriuretic peptide (BNP) or N-terminal pro-BNP can be elevated as a marker of myocardial stress usually reflecting the presence of right heart failure or PAH. [bib_ref] Role of N-terminal brain natriuretic peptide (N-TproBNP) in scleroderma-associated pulmonary arterial hypertension, Williams [/bib_ref] Pulmonary artery hypertension Pulmonary hypertension (PH) is defined at right heart catheterization (RHC) as a mean pulmonary artery pressure (mPAP)  25 mmHg. The current system of classification identifies five major groups, which define treatment and prognosis. [bib_ref] Pulmonary hypertension: diagnosis and management, Kiely [/bib_ref] [bib_ref] ASPIRE registry: assessing the Spectrum of Pulmonary hypertension Identified at a REferral..., Hurdman [/bib_ref] PAH is a rare form of pulmonary hypertension due to a vasculopathy. PAH complicating SSc has a poor prognosis significantly worse than idiopathic PAH [bib_ref] ASPIRE registry: assessing the Spectrum of Pulmonary hypertension Identified at a REferral..., Hurdman [/bib_ref] [bib_ref] Connective tissue disease-associated pulmonary arterial hypertension in the modern treatment era, Condliffe [/bib_ref] and requires specific vascular endothelium-targeted therapy. However, given the high prevalence of co-existing cardiac and lung disease, PH is also commonly seen in SSc in the presence of pulmonary hypertension-left heart disease (PH-LHD) and interstitial lung disease (PH-lung), where treatment of pulmonary hypertension should be directed at the underlying SSc-related heart or lung disease. Distinguishing these forms of pulmonary hypertension can be challenging in SSc, however, it is important not only in defining treatment but also survival. Indeed, patients with SSc and PH-lung have a worse prognosis than other PAH patients [bib_ref] Connective tissue disease-associated pulmonary arterial hypertension in the modern treatment era, Condliffe [/bib_ref] [bib_ref] Survival in pulmonary hypertension associated with the scleroderma spectrum of diseases: impact..., Mathai [/bib_ref] while SSc patients with PH-LD appear to have a significantly better prognosis. [bib_ref] ASPIRE registry: assessing the Spectrum of Pulmonary hypertension Identified at a REferral..., Hurdman [/bib_ref] A large metaanalysis 35 from a number of registries identified a 1-year survival of 81% and 3-year survival of 52% in patients with SSc and PAH. Depending on the method used to diagnose PAH, its prevalence varies widely. However, using RHC as the gold standard, a metaanalysis has calculated a prevalence of PAH in SSc of 9%. [bib_ref] Prevalence of pulmonary hypertension in systemic sclerosis in European Caucasians and metaanalysis..., Avouac [/bib_ref] Screening for PAH in SSc with echocardiography is advocated by the European Society of Cardiology and European Respiratory Societies (ESC/ERS), who use tricuspid regurgitation velocity jet to decide on the need for further investigation. [bib_ref] ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: the joint..., Galie [/bib_ref] However, a single threshold at echocardiography cannot be used to confidently exclude PAH, because tricuspid regurgitation velocity is not always present and/or can be eccentric leading to lower tricuspid regurgitation velocity, and in some studies comparing RHC to Doppler, tricuspid regurgitation velocity did not accurately reflect invasive pressures. [bib_ref] Evidence-based detection of pulmonary arterial hypertension in systemic sclerosis: the DETECT study, Coghlan [/bib_ref] We and others have described the inaccuracies of echocardiographic systolic arterial pressure estimation. [bib_ref] Inaccuracy of Doppler echocardiographic estimates of pulmonary artery pressures in patients with..., Rich [/bib_ref] [bib_ref] Accuracy of Doppler echocardiography in the hemodynamic assessment of pulmonary hypertension, Fisher [/bib_ref] Furthermore, in the absence of lung disease, a significantly reduced free diffusion of carbon monoxide (DLCO) had high specificity, but no threshold could be used to confidently exclude PAH. [bib_ref] Echocardiography and pulmonary function as screening tests for pulmonary arterial hypertension in..., Mukerjee [/bib_ref] Consequently, a complex scoring system, DETECT has been advocated as a screening tool for PAH in SSc 38 and this study reports a much higher sensitivity than echocardiography alone. The DETECT algorithm missed 4% of PAH patients (false negatives), but recommended RHC in 62% of patients while the strategy following 2009 ESC/ERS guidelines 37 missed 29% of diagnoses, and required a RHC referral rate of 40%. A limitation of the DETECT study is that this algorithm was only validated for patients with a SSc diagnosis of 43 years and a DLCOo60%. Therefore, it is likely that the value of the proposed algorithm is less accurate for those SSc patients with early rapidly progressive SSc within o4 years after onset of diagnosis, who are the best candidates for AHSCT.
There is also increasing interest in the outcome of patients with SSc who do not by strict criteria have pulmonary hypertension, but have mPAP measured at basal RHC in the range [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] [bib_ref] Hematopoietic stem cell transplantation for systemic sclerosis: if you are confused, remember:..., Burt [/bib_ref] [bib_ref] Consensus statement concerning cardiotoxicity occurring during haematopoietic stem cell transplantation in the..., Saccardi [/bib_ref] [bib_ref] Cardiac involvement in systemic sclerosis assessed by tissue-doppler echocardiography during routine care:..., Meune [/bib_ref]. Two studies identified that between 31 and 55% of these patients went on to develop resting PAH with a significant proportion doing so within 1 year of follow-up. [bib_ref] Borderline mean pulmonary artery pressure in patients with systemic sclerosis: transpulmonary gradient..., Valerio [/bib_ref] [bib_ref] Baseline characteristics and follow-up in patients with normal haemodynamics versus borderline mean..., Bae [/bib_ref] These borderline patients will require careful assessment to exclude left heart disease. If transplanted, careful follow-up in prospective registries is important to ensure that they do not have a high medium-term mortality risk related to the early development of PAH. Given these uncertainties, there should be a low threshold for performing RHC in SSc patients considered for AHSCT. Performance of RHC appears a sensible mandatory requirement to exclude or confirm PAH in SSc patients considered for AHSCT, since when using the current cyclophosphamide intense transplant regimens, PAH is a contraindication to AHSCT. [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] [bib_ref] Haematopoietic SCT in severe autoimmune diseases: updated guidelines of the European Group..., Snowden [/bib_ref] Interstitial lung disease ILD is common in SSc patients and almost a uniform finding at post mortem. [bib_ref] Pathologic observations in systemic sclerosis (scleroderma). A study of fifty-eight autopsy cases..., Fries [/bib_ref] It ranges from a relatively limited and slowly progressive condition seen most frequently in limited cutaneous-SSc to a more florid, rapidly progressive form seen more commonly dc-SSc. High resolution (HR) computed tomography has revolutionized the identification and clinical assessment of ILD and is more sensitive than chest radiograph. [bib_ref] Connective tissue disease related fibrotic lung disease: high resolution computed tomographic and..., Walsh [/bib_ref] A number of highresolution computed tomography patterns correlate with histological changes: including: (i) non-specific interstitial pneumonia, which is the most commonly observed and characterized by a mixture of ground glass change and fine reticular abnormalities often extending sub-pleural to the medulla, (ii) usual interstitial pneumonitis, characterized by sub-pleural reticular changes with irregular linear opacities and cyst formation/honeycombing with no or minimal ground glass change (iii) organizing pneumonia, usually bilateral and consisting of areas of consolidation/nodular change. Assessing the severity of lung disease to define clinical course and help in decisions regarding the risk-benefit ratio of AHSCT can be challenging. Detailed assessment using volume CT to evaluate the extent of lung disease plus lung function testing is required to exclude patients at higher risk of TRM, but also importantly to gain prospective data on potential treatment benefits.

## How to assess cardiopulmonary involvement in ssc patients before referral for transplant
Transthoracic echocardiography Although TTE, as routinely performed in SSc patient follow-up is not without limitations, it provides important information [fig_ref] Table 1: Transthoracic echocardiography Two-dimensional and M-mode echocardiography LV or RV hypertrophy LV mass... [/fig_ref].
Two-dimensional and M-mode echocardiographic findings that should be investigated include (1) significant LV or RV hypertrophy, (2) overt RV or LV wall motion abnormalities (including diastolic interventricular septal bounce), (3) significant pericardial effusion, (4) RV systolic dysfunction and (5) LV systolic dysfunction. Important Doppler findings on TTE that must be evaluated further in SSc prior to AHSCT include the following: (1) any hemodynamically significant stenotic or regurgitant valvular lesions, (2) elevated systolic arterial pressure, (3) notching in the RV outflow tract pulse Doppler tracing, a sign of pulmonary hypertension 47 or (4) moderate or greater LV diastolic dysfunction for the diagnosis and grading of LV diastolic dysfunction. [bib_ref] Expert consensus for multimodality imaging evaluation of adult patients during and after..., Plana [/bib_ref] Pulse wave tissue Doppler imaging of the lateral (anterior) tricuspid annulus and septal and lateral mitral annulus should be performed on all SSc patients undergoing evaluation for HSCT. Tissue Doppler imaging evaluation of the RV (tricuspid annulus) and LV (lateral mitral annulus) can provide important clues to the diagnosis of RV and LV dysfunction, respectively.
Speckle-tracking echocardiography, a method for quantitating myocardial mechanics that can detect subtle abnormalities in myocyte calcium cycling and myocardial fibrosis, [bib_ref] Ultrastructural and cellular basis for the development of abnormal myocardial mechanics during..., Shah [/bib_ref] is also an important tool for analyzing subclinical myocardial dysfunction in SSc. [bib_ref] Left ventricular dysfunction assessed by speckle-tracking strain analysis in patients with systemic..., Yiu [/bib_ref] It remains to be seen whether speckle-tracking indices such as global longitudinal strain and early diastolic strain rate of both the LV and RV will be helpful beyond the other, more routine testing (TTE, CMR and invasive hemodynamic testing with fluid challenge) that we currently recommend for pre-AHSCT evaluation in the SSc patient.
Cardiac magnetic resonance imaging CMR has emerged as the gold standard to assess right and left ventricular systolic function (LVSF), myocardial fibrosis and pericardial disease. It provides important complementary information not necessarily detected by TTE. [bib_ref] Cardiac magnetic resonance imaging in systemic sclerosis: a cross-sectional observational study of..., Hachulla [/bib_ref] In a consecutive series of SSc patients, TTE detected abnormalities in only 45% when CMR observed abnormalities in 75% of cases. [bib_ref] Cardiac magnetic resonance imaging in systemic sclerosis: a cross-sectional observational study of..., Hachulla [/bib_ref] In fact, in patients with SSc, ECG, CMR and RHC without and with a fluid challenge provide independent assessments of cardiac response to stress and are all required to adequately assess pre-AHSCT risk.
Ventricular morphology and function. Cine CMR is considered the gold standard technique for quantifying ventricular mass, volumes and function. Without the need for contrast, the high blood-myocardial signal difference improves endocardial border definition resulting in superior inter-study reproducibility for left ventricular volumes, function and mass when compared to ECG. [bib_ref] Comparison of interstudy reproducibility of cardiovascular magnetic resonance with two-dimensional echocardiography in..., Grothues [/bib_ref] In 50 SSc patients free of cardiac symptoms, CMR detected lower RV ejection fraction compared with controls, and lower RV EF in dc-SSc compared with lc-SSc suggesting a role for CMR in identifying subclinical RV dysfunction in SSc patients. [bib_ref] Cardiac magnetic resonance imaging detects subclinical right ventricular impairment in systemic sclerosis, Bezante [/bib_ref] Cine CMR is the best method to detect diastolic flattening of the interventricular septum 'D-sign', an indicator of either right- sided volume or pressure overload and elevated pulmonary vascular resistance or in the absence of PH and of RV systolic dysfunction with a constrictive and/or restrictive physiology.
Myocardial tissue characterization. Late gadolinium-enhanced CMR (LGE-CMR) can accurately identify the presence, location, size and morphology of irreversibly damaged myocardium. Regions of focal myocardial fibrosis become enhanced relative to healthy myocardium several minutes after administration of a gadolinium-based contrast agent. In the chronic setting, fibrotic tissue has a larger interstitial space than normal myocardium leading to a higher regional concentration of extracellular contrast agent, more T1 shortening and brighter signal. In SSc patients, focal myocardial fibrosis may result from recurrent vasospasm, ischemia-reperfusion injury and inflammation. Focal myocardial fibrosis is frequently seen in SSc patients by LGE-CMR (14% to 66%). [bib_ref] Cardiac magnetic resonance imaging in systemic sclerosis: a cross-sectional observational study of..., Hachulla [/bib_ref] [bib_ref] Myocardial perfusion-fibrosis pattern in systemic sclerosis assessed by cardiac magnetic resonance, Mavrogeni [/bib_ref] [bib_ref] Pattern and distribution of myocardial fibrosis in systemic sclerosis: a delayed enhanced..., Tzelepis [/bib_ref] [bib_ref] Early assessment of sub-clinical cardiac involvement in systemic sclerosis (SSc) using delayed..., Di Cesare [/bib_ref] In SSc autopsy studies, the majority of myocardial fibrosis was evident only on microscopic examination. [bib_ref] Myocardial lesions of progressive systemic sclerosis. A cause of cardiac dysfunction, Bulkley [/bib_ref] This type of diffuse fibrosis may be underestimated or even missed by LGE-CMR, which relies on differential contrast uptake between diseased and normal myocardium. Newer techniques employing T1 mapping now enable quantification of diffuse myocardial fibrosis by calculating the myocardial extracellular volume fraction. [bib_ref] Subclinical myocardial inflammation and diffuse fibrosis are common in systemic sclerosis--a clinical..., Ntusi [/bib_ref] Pericardial disease is common in SSc and can include pericardial effusion, pericarditis, cardiac tamponade and constrictive pericarditis. Pericardial effusions are well seen both on cine and LGE imaging. Increased ventricular interdependence is manifested as a 'septal bounce'-early diastolic flattening or inversion of the interventricular septum seen during inspiration followed by a right-sided septal shift during exhalation seen on free breathing cine CMR.
Myocardial perfusion. SSc is often complicated by microvascular coronary artery disease, which manifests as diffuse limitation in vasodilator reserve. CMR first-pass perfusion imaging has a higher spatial resolution, and can detect subendocardial perfusion defects that are below the resolution afforded by single-photon If RA pressure is  12 mmHg and PAWP  20 mmHg at rest, we recommend intravenous fluid challenge with 10 cc/kg warmed normal saline, infused over a 10-min period. The RA, PA and PAWP pressure should be measured, along with the cardiac output, immediately after the fluid challenge. Signs that demonstrate inability of the SSc patient to handle a volume load include:
(1) RA pressure post 4PCWP post or RA pressure 4PCWP, which are signs of RV dysfunction.. In SSc patients treated with nifedipine, the upslope ratio of CMR perfusion time-intensity curves in the myocardium and blood (a semi-quantitative index of myocardial perfusion) increased from baseline after 14 days of treatment. Because the diffuse microvascular coronary artery disease seen in SSc results in global reduction in myocardial perfusion, quantification of perfusion 61 may provide advantages over visual assessment and analysis techniques that rely on relative perfusion differences between adjacent segments.
Diastolic dysfunction. Advancements in CMR velocity encoding techniques now allow accurate measurement of blood and myocardial velocities. Emerging techniques enabling quantification of myocardial perfusion, myocardial diffuse fibrosis and diastolic dysfunction are likely to further enhance the utility of CMR in the evaluation of SSc patients for AHSCT.
Right heart catheterization with fluid challenge RHC is considered the gold standard test for the diagnosis of PAH, [bib_ref] Pulmonary hypertension, Shah [/bib_ref] and is an essential part of the diagnostic work-up for both . Baselines evaluation and SSc patient selection prior to HSCT according to ADWP consensus Suggested baseline evaluations History Complete history and examination including evaluation of quality of life by SHAQ-VAS, and/ or SF-36 questionnaires and of the extent of skin thickening by the mRSS. Standard hematological, biological and urinary analyses and viral serologies Blood cell count, ESR. Chemistry: electrolytes, renal and liver function tests, proteins, CK, BNP or NT-proBNP, troponin T or troponin I, CRP. Urine: protein/creatinine ratio; urine analysis, casts. Viral serologies: CMV, HSV, VZV, EBV, VDRL, HIV,, Hepatitis B and C and autoantibody titers. Immunology according to EBMT/EULAR Consensus Core Set ANA, anti-Scl-70, anti-centromere and anti-polymerase RNA III antibodies (indicates high risk for renal crisis).
Immune-phenotyping by FACS of peripheral blood mononuclear cells = CD3 + , CD4 + , CD8 + , CD4 + CD45RA, CD4 + CD45RO, CD31, CD3  CD56 + CD16 + , CD19 + , CD14 + ; IgG, IgA, IgM PAH and constrictive pericarditis. [bib_ref] Constrictive pericarditis in the modern era: a diagnostic dilemma, Nishimura [/bib_ref] Given the inability to reliably exclude PAH using non-invasive techniques, all SSc patients should undergo RHC during evaluation for AHSCT [fig_ref] Table 2: RHC with fluid challenge RA pressure tracing Kussmaul's sign [/fig_ref] , and the test should be performed and interpreted by operators experienced in hemodynamic testing. It is important to ensure proper zeroing of the pressure transducer, and all pressures should be measured at end-expiration (at which time intrathoracic pressure is closest to zero). On the right atrial (RA) pressure tracing, evidence of increased RV stiffness includes a prominent A wave (reflecting increased resistance to atrial contraction due to a non-compliant RV) and increased RA pressure during inspiration (Kussmaul's sign). Prominent V waves on the RA pressure tracing indicate significant tricuspid regurgitation. If any of these signs is present on the RA pressure tracing, the pre-transplant SSc patient should be further evaluated to determine whether there is significant RV fibrosis, primary RV failure, constrictive pericarditis or tricuspid regurgitation.
It is also helpful to analyze the PA pressure waveform on invasive hemodynamic testing [fig_ref] Table 2: RHC with fluid challenge RA pressure tracing Kussmaul's sign [/fig_ref]. Evidence of PAH or combined postand pre-capillary PAH on RHC testing are absolute contraindications for AHSCT in SSc. Patients with mild isolated pulmonary venous hypertension can undergo diuresis with re-evaluation, although these patients will be susceptible to adverse effects from fluid overload during AHSCT and should therefore be carefully evaluated to exclude significant LV systolic or diastolic dysfunction.
Fluid challenge during RHC is an important part of the pre-AHSCT evaluation in SSc as a method for understanding the cardiopulmonary response to increased volume. Although RHC is considered to be a gold standard for hemodynamic assessment, it only provides a snapshot of the patient at rest, and typically occurs after fasting for 48 h. Since AHSCT involves the administration of a considerable volume load, fluid challenge can be very helpful to examine the response of the cardiopulmonary system to increased volume in patients with SSc, and should be performed in all patients in whom resting RA pressure o12 mmHg and pulmonary capillary wedge pressure (PCWP) o20 mmHg. An exaggerated rise in RA pressure, mean PA pressure or PCWP, the emergence of a dip-and-plateau sign on RV pressure tracing, and/or lack of augmentation of cardiac output are all potential signs of a compromised SSc heart or pulmonary vasculature in need of further assessment and could signify the need to exclude patients from AHSCT. [bib_ref] Autologous hematopoietic stem cell transplant in systemic sclerosis: quantitative high resolution computed..., Launay [/bib_ref] [bib_ref] Cardiac involvement and treatment-related mortality after non-myeloablative haemopoietic stem-cell transplantation with unselected..., Burt [/bib_ref] SSC PATIENT SELECTION CRITERIA AND PROCEDURES FOR AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION Referral criteria Generally, patients should be considered for AHSCT if their age is under 65 and onset of SSc within 5 years, although patients with disease of up to 10 years duration have been transplanted without increased risk, provided pre-cardiac assessment was normal. Best candidates for AHSCT are patients within the first 4 years of rapidly progressive dc-SSc onset and a life-threatening condition with a 3-5 year survival, as well established by recent meta-analysis 3 and large EUSTAR prospective 4 studies. Until more cardiac-safe noncyclophosphamide intensive regimens are developed, only patients without evidence for PAH and sufficient cardiopulmonary function based on defined selection criteria [fig_ref] 2: Increased mean PA pressure post 435 mmHg, increased PVR post 43 Wood... [/fig_ref] , are eligible for AHSCT.
Procedures of AHSCT In October 2016, more than 2200 patients with autoimmune diseases treated by AHSCT have been reported to the EBMT database, including 440 patients with SSc, while 136 patients with SSc have been transplanted in Chicago. AHSCT procedures (mobilization, leukapheresis, conditioning, peripheral stem cell infusion, supportive and post-transplant care) are detailed in . Each center will follow its own local protocol for AHSCT with regard to the risk/benefit balance after careful standard clinical and biological patient pre-transplant evaluation, whereas the local treatment regimen and follow-up evaluation will be recorded and analyzed according to ADPW guidelines. [bib_ref] Haematopoietic SCT in severe autoimmune diseases: updated guidelines of the European Group..., Snowden [/bib_ref] [bib_ref] SCT for severe autoimmune diseases: consensus guidelines of the European Society for..., Alexander [/bib_ref] CONCLUSIONS Recently published evidence in randomized controlled trials has shown significant improvement in organ function, quality of life, disability and long-term survival. However, because of vital organ . AHSCT procedures according to EBMT and international consensus

## Mobilization and leukapheresis
PBSCs may be mobilized using either cyclophosphamide 2g/m 2 infused in one session or 4g/m 2 divided equally over 2 consecutive days followed by G-CSF 5-10 g/kg/day and leukapheresis according to institutional protocols. A minimum of 3.0  10 6 /kg CD34 + at harvest and freeze resulting in minimum 2.0  10 6 /kg viable CD34 + cells is required for transplant.

## Conditioning and peripheral stem cell infusion
Conditioning should not be initiated until at least 3-4 weeks of mobilization cyclophosphamide dose to minimize accumulated acute cyclophosphamide myocardial injury. Prior to conditioning a central venous catheter will be placed. The current published conditioning regimen consists of cyclophosphamide 50 mg/kg/day intravenously for 4 consecutive days (total 200 mg/kg) and rbATG (thymoglobulin) at total doses of 6.5-7.5 mg/kg, delivered according to institutional protocols. Given the potential of ATG-induced fever to destabilize patients, intravenous methylprednisolone 43-10 mg/kg will be given to improve tolerability of the rbATG and decrease fever. ATG fever is also minimized by limiting the first dose of ATG to not more than 0.5 mg/kg. The interval between the last dose of cyclophosphamide and infusion of the graft should be at least 48 h. On day 0 stem cells are thawed and infused according to local standard operating procedures. The minimum number of CD34 + cells reinfused should be 2  10 6 /kg, whether the graft is unselected or CD34 + selected. Supportive care Supportive care measures, including prophylactic or therapeutic antibiotics, anti-viral, anti-pneumocystis and anti-fungal agents, will be taken according to local standard operating procedures for such patients. Adherence to specific guidelines is recommended (according to EBMT standards).
Transfusions will be given in accordance with local standard operating procedures for such patients. Based on current transplantation-experiences in scleroderma patients, particular attention should be paid to thrombocytopenia, bleeding tendency, hypo and hypertension, and respiratory insufficiency. For both mobilization and conditioning, cyclophosphamide should be given with appropriate hydration and mesna (to prevent hemorrhagic cystitis), but extreme care must be taken in fluid balance management as patients are sensitive to overload.
Abbreviations: AHSCT = autologous hematopoietic stem cell transplantation; EBMT = European Society for Blood and Marrow Transplantation; rbATG = rabbit antithymocyte globulin.
Cardiopulmonary evaluation in systemic sclerosis D Farge et al damage caused by SSc, the risks of transplant-related complications and treatment-related mortality risks have been relatively high compared with other diseases. There is a need for more thorough screening and evaluation of patients, as described herein, to decrease the risk of transplant toxicity within specialized centers of SSc-related transplant expertise.
[fig] Figure 1: (a, b) Cine CMR: A four chamber view (left) with positions of each slice of a short axis stack (right). Imaging is performed in the 2chamber, 3-chamber and 4-chamber long axis views and in a stack of short axis slices, typically acquired every 10 mm from the mitral valve plane to the apex. Mass and volume are quantified from the short axis stack according to Simpson's Rule by slice summation, which avoids making any geometric assumptions about the shape of the ventricle. The high blood-myocardial contrast and ability to quantify volumes without geometric assumptions is especially useful in the RV, because of its complex shape, abundant trabeculations and thin wall. Because gadolinium contrast agents are confined to the extracellular space, the change in T1 relaxation time is inversely related to the contrast agent volume of distribution. Even without the administration of contrast, native T1 mapping detects prolongation of T1 in SSc. Active inflammation can be assessed by T2-weighted images, which demonstrate increased signal in areas of myocardial edema. Abnormal myocardial T2 signal has been described in patients with SSc. 50 Endocardial (blue) and epicardial (yellow) borders are drawn, enabling calculation of left ventricular mass and chamber volume according to Simpson's rule.55 (c) Diastolic flattening of interventricular septum, 'D-sign' , visualized by cine CMR. Adapted from Burt et al. 22 http://www.jrheum.org/content/39/2/206.long, reproduced with permission from Journal of Rheumatology and Richard Burt. (d) Focal fibrosis in a SSc patient involving the mid and epicardial myocardium, sparing the subendocardium, as visualized by LGE-CMR. Because gadolinium contrast agents are confined to the extracellular space, the change in T1 relaxation time is inversely related to the contrast agent volume of distribution. CMR measurement of the relative gadolinium concentration in the blood and myocardium, and the direct measurement of the volume of distribution of gadolinium in the blood (1-hematocrit), enables calculation of extracellular volume fraction (ECV), an index of the volume of distribution of contrast agent in the myocardium. Adapted from Burt et al. 22 http://www.jrheum.org/ content/39/2/206.long, 20 reproduced with permission from Journal of Rheumatology and Richard Burt. (e, f) Pericardial effusion seen as bright white on Cine CMR (left) and dark black on phase sensitive inversion recovery LGE-CMR (right). Pericardial thickening and enhancement are also seen on LGE-CMR. (g) Global subendocardial hypoperfusion in a SSc patient seen on adenosine stress CMR perfusion imaging. [/fig]
[fig] 2: Increased mean PA pressure post 435 mmHg, increased PVR post 43 Wood units or increased DPG post 47 mmHg, which are indicative of stiff pulmonary vasculature. (3) Increased PAWP post 425 mmHg, which is indicative of LV diastolic dysfunction. (4) Unchanged or decreased cardiac output post, which is indicative of RV or LV dysfunction. (5) Exaggerated dip-and-plateau pattern in the RV pressure tracing, which is a sign of restrictive or constrictive physiology. Abbreviations: DPG = diastolic pulmonary vascular pressure gradient; LV = left ventricle; PA = pulmonary artery; PAWP = pulmonary arterial wedge pressure; PCWP = pulmonary capillary wedge pressure; PVR = pulmonary vascular resistance; RA = right atrial; RHC = right heart catheterization; RV = right ventricle; SSc = systemic sclerosis. [/fig]
[table] Table 1: Transthoracic echocardiography Two-dimensional and M-mode echocardiography LV or RV hypertrophy LV mass index 495 g/m 2 in women or 4115 g/m 2 in men, or RV free wall thickness in end-diastole 45 mm in the subcostal view. RV or LV wall motion abnormalities Diastolic interventricular septal bounce (sign of ventricular interdependence) or systolic or diastolic septal flattening of the interventricular septum (indicative of RV pressure or volume overload, respectively). Significant pericardial effusion Diameter 41 cm at ventricular end-diastole. RV systolic dysfunction RV fractional area change (apical 4-chamber view (RV end-diastolic area-RV end-systolic area)/RV end-diastolic area) o35% or TAPSE o16 mm. RV TDI s' velocity o 10 cm/s is indicative of RV systolic dysfunction. 62 TDI evaluation of the LV On the LV side, a lateral s' velocity o8 cm/s is indicative of LV systolic dysfunction. For evidence of LV diastolic dysfunction on TDI, it is helpful to use age-specific cut-offs of lateral e' velocity 63 which have been used in Abbreviations: LV = left ventricle; RV = right ventricle; TAPSE = tricuspid annular plane systolic excursion; TDI = tissue Doppler imaging. [/table]