The prognostic relevance of exercise pulmonary hypertension in cardiac and pulmonary diseases

PURPOSE OF REVIEW

In this review, we provide an overview of the prognostic implications of exPH in patients with various common cardiac and pulmonary diseases.

RECENT FINDINGS

Exercise pulmonary hypertension (exPH) has been recently re-introduced in the current European Society of Cardiology/European Respiratory Society pulmonary hypertension guidelines. Accordingly, exPH is defined as a mean pulmonary arterial pressure (mPAP)/cardiac output (CO) slope greater than 3 mmHg/l/min. Key considerations for this re-introduction included increasing understanding on normal pulmonary hemodynamics during exercise and the broadly available evidence on the association of an abnormal mPAP/CO slope with poor survival in the general population and in different disease entities.

SUMMARY

Exercise (patho-)physiology has opened a new field for clinical research facilitating recognition of cardiovascular and pulmonary vascular diseases in an early stage. Such early recognition with significant prognostic and possibly therapeutic relevance, but being undetectable at rest, makes exercise pulmonary hemodynamics particularly interesting for common diseases, such as valvular heart disease, left heart disease, and chronic pulmonary disease.

Updated definition of exercise pulmonary hypertension

In the recently published European Society of Cardiology/European Respiratory Society guidelines on the diagnosis and treatment of pulmonary hypertension (PH) the haemodynamic definitions of PH were updated and a new definition for exercise PH was introduced. Accordingly, exercise PH is characterised by a mean pulmonary arterial pressure/cardiac output (CO) slope >3 Wood units (WU) from rest to exercise. This threshold is supported by several studies demonstrating prognostic and diagnostic relevance of exercise haemodynamics in various patient cohorts. From a differential diagnostic point of view, an elevated pulmonary arterial wedge pressure/CO slope >2 WU may be suitable to identify post-capillary causes of exercise PH. Right heart catheterisation remains the gold standard to assess pulmonary haemodynamics both at rest and exercise. In this review, we discuss the evidence that led to the reintroduction of exercise PH in the PH definitions.

High prevalence of occult left ventricular diastolic dysfunction detected by exercise stress test in systemic sclerosis

Despite the poor prognosis of systemic sclerosis (SSc) due to the co-occurrence of left ventricular diastolic dysfunction (LVDD), presence of occult LVDD has not been sufficiently investigated. This retrospective study aimed to reveal the prevalence and determinants of occult LVDD in patients with SSc by exercise stress test. Forty-five SSc patients (age, 63 ± 13 years; men/women, 6/39) with normal pulmonary artery pressure and pulmonary artery wedge pressure (PAWP) at rest underwent a symptom-limited exercise test with right heart catheterization using a supine cycle ergometer; haemodynamic parameters at rest, leg raise and during exercise were evaluated. Occult LVDD defined PAWP ≥ 25 mmHg during exercise was seen in 13 patients (29%). Higher PAWP, lower pulmonary vascular resistance and diastolic pulmonary pressure gradient, larger left atrium at rest, and higher PAWP during leg raise (15 ± 4 vs 10 ± 4 mmHg in non-LVDD group, p < 0.001) were observed in the occult LVDD group. The area under the ROC curve for PAWP after leg raise was largest at 0.83 (95% CI: 0.70–0.95, p = 0.001). About one-third (29%) of SSc patients with normal haemodynamics at rest showed occult LVDD. A higher PAWP after leg raise could be useful for detecting occult LVDD.

Exercise and fluid challenge during right heart catheterisation for evaluation of dyspnoea

This prospective study compared exercise test and intravenous fluid challenge in a single right heart catheter procedure to detect latent diastolic heart failure in patients with echocardiographic heart failure with preserved ejection function. We included 49 patients (73% female) with heart failure with preserved ejection function and pulmonary artery wedge pressure ≤15 mmHg. A subgroup of 26 patients had precapillary pulmonary hypertension. Invasive haemodynamic and gas exchange parameters were measured at rest, 45° upright position, during exercise, after complete haemodynamic and respiratory recovery in lying position, and after rapid infusion of 500 mL isotonic solution. Most haemodynamic parameters increased at both exercise and intravenous fluid challenge, with the higher increase at exercise. Pulmonary vascular resistance decreased by –0.21 wood units at exercise and –0.56 wood units at intravenous fluid challenge (p = 0.3); 20% (10 of 49) of patients had an increase in pulmonary artery wedge pressure above the upper limit of 20 mmHg at exercise, and 20% above the respective limit of 18 mmHg after intravenous fluid challenge. However, only three patients exceeded the upper limit of pulmonary artery wedge pressure in both tests, i.e. seven patients only at exercise and seven other patients only after intravenous fluid challenge. In the subgroup of pulmonary hypertension patients, only two patients exceeded pulmonary artery wedge pressure limits in both tests, further five patients at exercise and four patients after intravenous fluid challenge. A sequential protocol in the same patient showed a significantly higher increase in haemodynamic parameters at exercise compared to intravenous fluid challenge. Both methods can unmask diastolic dysfunction at right heart catheter procedure, but in different patient groups.

Progress in Understanding, Diagnosing, and Managing Cardiac Complications of Systemic Sclerosis

PURPOSE OF THE REVIEW

Systemic sclerosis (scleroderma) is a complex autoimmune disease that commonly involves the cardiovascular system. Even if often subclinical, cardiac involvement is considered a poor prognostic factor as it is a leading cause of death in scleroderma patients. We review the cardiac manifestations of scleroderma, the diagnostic methods useful in detection, and current advances in therapeutic management.

RECENT FINDINGS

Beside the routine exams for the assessment of cardiac status (including EKG, standard echocardiography, provocative tests) novel techniques such as myocardial strain imaging on echocardiography, cardiac magnetic resonance imaging, invasive hemodynamic assessment, and endomyocardial biopsy have been demonstrated to be useful in understanding the cardiac alterations that typically affect scleroderma patients. Recent application of novel cardiac detection strategies is providing increased insight into the breadth and pathogenesis of cardiac complications of scleroderma. Further studies coupling exercise provocation, invasive and imaging assessment, and mechanistic studies in scleroderma cardiac tissue are needed to develop the optimal approach to early detection of cardiac disease in scleroderma and targeted therapies.

Potential role of exercise echocardiography and right heart catheterization in the detection of early pulmonary vascular disease in patients with systemic sclerosis

Pulmonary vascular disease represents one of the most frequent complications in systemic sclerosis leading to increased mortality. The recognition and appropriate clinical management of early pulmonary vascular disease could significantly improve the prognosis of affected patients. Early pulmonary vascular disease is characterized by the histological signs of pulmonary vascular remodeling, mildly increased mean pulmonary arterial pressure (21–24 mmHg) at rest, abnormal pulmonary hemodynamics during exercise, decreased exercise capacity, and a high risk for development of pulmonary arterial hypertension. Pulmonary hemodynamics can be investigated during exercise by echocardiography or by right heart catheterization both representing important clinical tools for the screening and confirmation of early pulmonary vascular disease. Further studies are needed to better understand the clinical course of systemic sclerosis patients with early pulmonary vascular disease and to define the characteristics of patients that will or will not profit from pulmonary arterial hypertension treatment.

An official European Respiratory Society statement: pulmonary haemodynamics during exercise

There is growing recognition of the clinical importance of pulmonary haemodynamics during exercise, but several questions remain to be elucidated. The goal of this statement is to assess the scientific evidence in this field in order to provide a basis for future recommendations.

Right heart catheterisation is the gold standard method to assess pulmonary haemodynamics at rest and during exercise. Exercise echocardiography and cardiopulmonary exercise testing represent non-invasive tools with evolving clinical applications. The term “exercise pulmonary hypertension” may be the most adequate to describe an abnormal pulmonary haemodynamic response characterised by an excessive pulmonary arterial pressure (PAP) increase in relation to flow during exercise. Exercise pulmonary hypertension may be defined as the presence of resting mean PAP <25 mmHg and mean PAP >30 mmHg during exercise with total pulmonary resistance >3 Wood units. Exercise pulmonary hypertension represents the haemodynamic appearance of early pulmonary vascular disease, left heart disease, lung disease or a combination of these conditions. Exercise pulmonary hypertension is associated with the presence of a modest elevation of resting mean PAP and requires clinical follow-up, particularly if risk factors for pulmonary hypertension are present. There is a lack of robust clinical evidence on targeted medical therapy for exercise pulmonary hypertension.

Treatment of pulmonary hypertension with left heart disease: a concise review

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure ≥ 25 mmHg, as determined by right heart catheterization. Pulmonary arterial hypertension (PAH) can no longer be considered an orphan disease given the increase in awareness and availability of new drugs. PH carries with it a dismal prognosis and leads to significant morbidity and mortality. Symptoms can range from dyspnea, fatigue and chest pain to right ventricular failure and death. PH is divided into five groups by the World Health Organization (WHO), based on etiology. The most common cause of PH in developed countries is left heart disease (group 2), owing to the epidemic of heart failure (HF). The data regarding prevalence, diagnosis and treatment of patients with group 2 PH is unclear as large, prospective, randomized controlled trials and standardized protocols do not exist. Current guidelines do not support the use of PAH-specific therapy in patients with group 2 PH. Prostacyclins, endothelin receptor antagonists, phosphodiesterase-5 inhibitors and guanylate cyclase stimulators have been tried in treatment of patients with HF and/or group 2 PH with mixed results. This review summarizes and critically appraises the evidence for diagnosis and treatment of patients with group 2 PH/HF and suggests directions for future research.

Rest and exercise echocardiography for early detection of pulmonary hypertension

Early detection of pulmonary hypertension (PH) is essential to ensure that patients receive timely and appropriate treatment for this progressive disease. Rest and exercise echocardiography has been used to screen patients in an attempt to identify early stage PH. However, current PH guidelines recommend against exercise tests because of the lack of evidence. We reviewed previous studies to discuss the current standpoint concerning rest and exercise echocardiography in PH. Around 20 exercise echocardiography studies were included to assess the cutoff value for exercise-induced pulmonary hypertension (EIPH). Approximately 40 exercise echocardiography studies were also included to evaluate the pulmonary artery pressure-flow relationship as assessed by the slope of the mean pulmonary artery pressure and cardiac output (ΔmPAP/ΔQ). There were several EIPH and ΔmPAP/ΔQ reference values in individuals with pulmonary vascular disease. We believed that assessing the ΔmPAP/ΔQ makes sense from a physiological standpoint, and the clinical value should be confirmed in future studies. Exercise echocardiography is an appealing alternative in PH. Further studies are needed to assess the prognostic value of the pulmonary artery pressure-flow relationship in high-risk subjects.

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

Guidelines summarize and evaluate all available evidence on a particular issue at the time of the writing process, with the aim of assisting health professionals in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.

Experience with exercise right heart catheterization in the diagnosis of pulmonary hypertension: a retrospective study

BACKGROUND

Data on exercise pulmonary hemodynamics in healthy people and patients with pulmonary hypertension (PH) are rare. We analyzed exercise right heart catheterization (RHC) data in a symptomatic collective referred with suspected PH to characterize the differential response by diagnostic groups, to correlate resting with exercise hemodynamics, and to evaluate safety.

METHODS

This is a retrospective single-center study reviewing data from patients in whom an exercise RHC was performed between January 2006 and January 2013. Patients with follow-up RHC under PH -therapy were excluded.

RESULTS

Data from 101 patients were analyzed, none of them had an adverse event. In 35% we detected a resting PH (27.8% precapillary, 6.9% postcapillary). Exercise PH (mean pulmonary arterial pressure (mPAP) >30 mmHg at exercise) was found in 38.6%, whereas in 25.7% PH was excluded. We found a remarkable number of exercise PH in scleroderma patients, the majority being postcapillary. 83% of patients with mPAP-values between 20 and 24.9 mmHg at rest had exercise PH. Patients with resting PH had worse hemodynamics and were older compared with exercise PH ones.

CONCLUSION

In this real-life experience in symptomatic patients undergoing exercise RHC for suspected PH, we found that exercise RHC is safe. The facts that the vast majority of patients with mPAP-values between 20 and 24.9 mmHg at rest had exercise PH and the older age of patients with resting PH may indicate that exercise PH is a precursor of resting PH. Whether earlier treatment start in patients with exercise PH would stabilize the disease should be addressed in future studies.

Definitions and diagnosis of pulmonary hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure ≥ 25 mm Hg at rest, measured during right heart catheterization. There is still insufficient evidence to add an exercise criterion to this definition. The term pulmonary arterial hypertension (PAH) describes a subpopulation of patients with PH characterized hemodynamically by the presence of pre-capillary PH including an end-expiratory pulmonary artery wedge pressure (PAWP) ≤ 15 mm Hg and a pulmonary vascular resistance >3 Wood units. Right heart catheterization remains essential for a diagnosis of PH or PAH. This procedure requires further standardization, including uniformity of the pressure transducer zero level at the midthoracic line, which is at the level of the left atrium. One of the most common problems in the diagnostic workup of patients with PH is the distinction between PAH and PH due to left heart failure with preserved ejection fraction (HFpEF). A normal PAWP does not rule out the presence of HFpEF. Volume or exercise challenge during right heart catheterization may be useful to unmask the presence of left heart disease, but both tools require further evaluation before their use in general practice can be recommended. Early diagnosis of PAH remains difficult, and screening programs in asymptomatic patients are feasible only in high-risk populations, particularly in patients with systemic sclerosis, for whom recent data suggest that a combination of clinical assessment and pulmonary function testing including diffusion capacity for carbon monoxide, biomarkers, and echocardiography has a higher predictive value than echocardiography alone.

Determinants of exercise-induced pulmonary arterial hypertension in systemic sclerosis

BACKGROUND

Exercise-induced pulmonary arterial hypertension (EIPH) in systemic sclerosis (SSc) has already been observed but its determinants remain unclear. The aim of this study was to determine the incidence and the determinants of EIPH in SSc.

METHODS AND RESULTS

We prospectively enrolled 63 patients with SSc (age 54±3years, 76% female) followed in CHU Sart-Tilman in Liège. All patients underwent graded semi-supine exercise echocardiography. Systolic pulmonary arterial pressure (sPAP) was derived from the peak velocity of the tricuspid regurgitation jet and adding the estimation of right atrial pressure, both at rest and during exercise. Resting pulmonary arterial hypertension (PH) was defined as sPAP > 35 mmHg and EIPH as sPAP > 50 mmHg during exercise. The following formulas were used: mean PAP (mPAP) = 0.61 × sPAP + 2, left atrial pressure (LAP)=1.9+1.24 × left ventricular (LV) E/e' and pulmonary vascular resistance (PVR)=(mPAP-LAP)/LV cardiac output (CO) and slope of mPAP-LVCO relationship=changes in mPAP/changes in LVCO. Resting PH was present in 3 patients (7%) and 21 patients developed EIPH (47%). Patients with EIPH had higher resting LAP (10.3 ± 2.2 versus 8.8 ± 2.3 mmHg; p = 0.03), resting PVR (2.6 ± 0.8 vs. 1.4 ± 1.1 Woods units; p=0.004), exercise LAP (13.3 ± 2.3 vs. 9 ± 1.7 mmHg; p < 0.0001), exercise PVR (3.6 ± 0.7 vs. 2.1 ± 0.9 Woods units; p = 0.02) and slope of mPAP-LVCO (5.8 ± 2.4 vs. 2.9 ± 2.1 mmHg/L/min; p < 0.0001). After adjustment for age and gender, exercise LAP (β=3.1 ± 0.8; p=0.001) and exercise PVR (β=7.9 ± 1.7; p=0.0001) were independent determinants of exercise sPAP.

CONCLUSION

EIPH is frequent in SSc patients and is mainly related to both increased exercise LV filling pressure and exercise PVR.

Exaggerated increase of exercise-induced pulmonary artery pressure in systemic sclerosis patients predominantly results from left ventricular diastolic dysfunction

OBJECTIVE

High prevalence of exaggerated pulmonary artery pressure response to exercise (EPAPR) was reported in patients with systemic sclerosis (SSc). However, pathophysiology of this phenomenon has not been well defined. Therefore, we evaluated the frequency and potential aetiology of EPAPR in SSc patients.

METHODS

We included 85 patients (79 female, 6 male, mean age 54.3 ± 13.9 years) with SSc. Transthoracic echocardiography followed by exercise Doppler echocardiography (EDE) were performed. A positive EDE was defined when at least 20 mmHg increase of tricuspid regurgitation peak gradient (TRPG) was recorded. Right heart catheterization (RHC) with exercise was performed in positive EDE patients and in subjects with resting TRPG >31 mmHg.

RESULTS

Resting TRPG >31 mmHg and/or positive EDE was found in 30 patients and they were referred to RHC. Finally, RHC was performed in 20 patients (16 pts resting TRPG >31 mmHg and 4 others normal resting TRPG and positive EDE). In 12 (60 %) of them an EPAPR with elevated pulmonary capillary wedge pressure (PCWP) was observed. Interestingly, mean left atrium (LA) diameter was greater in an EPAPR with elevated PCWP patients than in subjects with normal exercise response (39.36 ± 5.6 vs. 35.53 ± 3.48, p = 0.03). In EPAPR with elevated PCWP group greater mean value of E/E' of mitral lateral annulus was observed (7.98 ± 3.35 vs. 6.27 ± 1.94, p = 0.03). In the univariate logistic regression analysis increased LA diameter was significant predictor of EPAPR with elevated PCWP (OR 1.199, 95 % CI 1.029-1.396, p = 0.019).

CONCLUSIONS

Despite very well-known risk of PAH in systemic sclerosis patients, the excessive increase of PAP during exercise is more commonly caused by left ventricular diastolic dysfunction than pulmonary arterial vasculopathy.