Association between lung ultrasound B-lines and exercise-induced pulmonary hypertension in patients with connective tissue disease.

BACKGROUND: Identification of elevation in pulmonary pressures during exercise may provide prognostic and therapeutic implications in patients with connective tissue disease (CTD). Interstitial lung disease (ILD) is common in CTD patients and subtle interstitial abnormalities detected by lung ultrasound could predict exercise-induced pulmonary hypertension (PH). METHODS AND RESULTS: Echocardiography and lung ultrasound were performed at rest and bicycle exercise in CTD patients (n = 41) and control subjects without CTD (n = 24). Ultrasound B-lines were quantified by scanning four intercostal spaces in the right hemithorax. We examined the association between total B-lines at rest and the development of exercise-induced PH during ergometry exercise. Compared to controls, the number of total B-lines at rest was higher in CTD patients (0 [0, 0] vs 2 [0, 9], P < .0001) and was correlated with radiological severity of ILD assessed by computed tomography (fibrosis score, r = .70, P < .0001). Pulmonary artery systolic pressure (PASP) was increased with ergometry exercise in CTD compared to controls (48 ± 14 vs 35 ± 13 mm Hg, P = .0006). The number of total B-lines at rest was highly correlated with higher PASP (r = .52, P < .0001) and poor right ventricular pulmonary artery coupling (tricuspid annular plane systolic excursion/PASP ratio, r = -.31, P = .01) during peak exercise. The number of resting B-lines predicted the development of exercise-induced PH with an area under the curve .79 (P = .0003). CONCLUSIONS: These data may suggest the value of a simple resting assessment of lung ultrasound as a potential tool for assessing the risk of exercise-induced PH in CTD patients.

Predictors of exercise-induced pulmonary hypertension in patients with connective tissue disease.

Screening and early detection of pulmonary arterial hypertension (PAH) in connective tissue disease (CTD) are currently recommended for early treatment. Exercise-induced pulmonary hypertension (EIPH) is thought to be a potential risk of developing resting pulmonary hypertension. However, accurate diagnosis of EIPH is needed hemodynamics by right heart catheterization during exercise. Therefore, we compared various parameters of EIPH group with non-EIPH group in patients with CTD. This study aimed to investigate noninvasive predictors of EIPH. A total of 162 consecutive patients with CTD who received screening of PAH was studied. Thirty-four patients with suspected PAH received right heart catheterization (RHC) at rest. Twenty-four patients without PAH underwent RHC during exercise, and they were divided into the EIPH group (n = 7) and the non-EIPH group (n = 17). Exercise tolerance such as 6-min walk distance and peak VO2/kg in the EIPH group was lower than that in the non-EIPH group. For hemodynamics, pulmonary artery pressure, right atrial pressure, and vascular resistance in the EIPH group were significantly higher than those in the non-EIPH group. In echocardiography, RV Tei index in the EIPH group was significantly higher than that in the non-EIPH group (EIPH vs non-EIPH = 0.42 [0.41, 0.47] vs 0.25 [0.20, 0.32], P = 0.007). The receiver operating characteristics curve showed a cutoff value of RV Tei index (0.41) with a sensitivity of 0.857 and specificity of 0.882. In conclusion, RV Tei index might be a feasible predictor of EIPH in patients with CTD.

Exercise-Induced Pulmonary Hypertension: Rationale for Correcting Pressures for Flow and Guide to Non-Invasive Diagnosis.

Exercise-induced pulmonary hypertension (exPHT) is a hemodynamic condition linked to increased morbidity and mortality across various cardiopulmonary diseases. Traditional definitions of exPHT rely on absolute cut-offs, such as mean pulmonary artery pressure (mPAP) above 30 mmHg during exercise. However, recent research suggests that these cut-offs may not accurately reflect pathophysiological changes, leading to false positives and false negatives. Instead, the mPAP over cardiac output (CO) slope, which incorporates both pressure and flow measurements, has emerged as a more reliable indicator. A slope exceeding 3 mmHg/L/min is now considered diagnostic for exPHT and strongly correlates with adverse outcomes. Stress echocardiography serves as a viable alternative to invasive assessment, enabling broader implementation. This review discusses the physiological basis of pulmonary hemodynamics during exercise, the advantages of the mPAP/CO slope over absolute pressure measurements, the evidence supporting its inclusion in clinical guidelines, and provides a practical guide for non-invasive determining the mPAP/CO slope in clinical practice.

Exercise Testing in Patients with Pulmonary Hypertension.

Pulmonary hypertension (PH), defined by a mean pulmonary artery pressure of >20 mm Hg, often presents with non-specific symptoms such as dyspnea and exercise intolerance, making it difficult to diagnose early before the onset of right heart dysfunction. Therefore, exercise testing can be of great utility for clinicians who are evaluating patients with an unclear etiology of exercise intolerance by helping identify the underlying mechanisms of their disease. The presence of PH is associated with adverse clinical outcomes, with distinct differences and patterns in the cardiovascular and ventilatory responses to exercise across various PH phenotypes. We discuss the role of exercise-invasive hemodynamic testing, cardiopulmonary exercise testing, and exercise stress echocardiography modalities across the spectrum of PH.

Chronic thromboembolic pulmonary disease: Association with exercise-induced pulmonary hypertension and right ventricle adaptation over time: Chronic thromboembolic pulmonary disease and exercise pulmonary hypertension.

BACKGROUND AND AIM: Chronic thromboembolic pulmonary disease (CTEPD) is a progressive condition caused by fibrotic thrombi and vascular remodeling in the pulmonary circulation despite prolonged anticoagulation. We evaluated clinical factors associated with CTEPD, as well as its impact on functional capacity, pulmonary haemodynamics at rest and after exercise, and right ventricle (RV) morphology and function. METHODS: We compared 33 consecutive patients with a history of acute pulmonary embolism and either normal pulmonary vascular imaging (negative Q-scan, group 1, n = 16) or persistent defects on lung perfusion scan (positive Q-scan) despite oral anticoagulation at 4 months (group 2, n = 17). Investigations included thrombotic load, the Pulmonary Embolism Severity Index (PESI) score, functional class, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), cardiopulmonary exercise test (CPET) and echocardiographic parameters at rest and after exercise (ESE), at 4 and at 24 months. RESULTS: Compared with group 1, group 2 featured a higher PESI score (p = 0.02) and a higher thrombotic load (p = 0.004) at hospital admission. At 4 months, group 2 developed exercise-induced pulmonary hypertension (Ex-PH) at CPET (p < 0.001) and ESE (p < 0.001). At 24 months group 2 showed higher NT-proBNP (p < 0.001), WHO-FC (p < 0.001), systolic (p<0.001) and diastolic (p = 0.037) RV dysfunction and worse RV-arterial coupling (p < 0.001) despite maintaining a low or intermediate echocardiographic probability of PH. CONCLUSIONS: This is the first "proof of concept" study showing that patients with a positive Q-scan frequently develop Ex-PH and RV functional deterioration as well as reduced functional capacity, generating the hypothesis that Ex-PH could help detect the progression to CTEPD.

Exercise-Induced Pulmonary Hypertension: A Valid Entity or Another Factor of Confusion?

Exercise-induced pulmonary hypertension EIPH has been defined as an increase in mean pulmonary arterial pressure (mPAP) during exercise in otherwise normal values at rest. EIPH reflects heart and/or lung dysfunction and may precede the development of manifest pulmonary hypertension (PH) in a proportion of patients. It is also associated with decreased life expectancy in patients with heart failure with reduced ejection fraction (HFrEF) or left ventricle (LV) valvular diseases. Diastolic dysfunction exacerbated during exercise relates to increased LV filling pressure and left atrial pressure (LAP). In this context backward, transmitted pressure alone or accompanied with backward blood flow promotes EIPH. The gold standard of EIPH assessment remains the right heart catheterization during exercise, which is an accurate but invasive method. Alternatively, non-invasive diagnostic modalities include exercise stress echocardiography (ESE) and cardiopulmonary exercise testing (CPET). Both diagnostic tests are performed under gradually increasing physical stress using treadmill and ergo-cycling protocols. Escalating workload during the exercise is analogous to the physiological response to real exercise. The results of the latter techniques show good correlation with invasive measurements, but they suffer from lack of validation and cut-off value determination. Although it is not officially recommended, there are accumulated data supporting the importance of EIPH diagnosis in the assessment of other mild/subclinical or probably fatal diseases in patients with latent PH or heart failure or LV valvular disease, respectively. Nevertheless, larger, prospective studies are required to ensure its role in clinical practice.

Cardiopulmonary Exercise Testing with Echocardiography to Identify Mechanisms of Unexplained Dyspnea.

Little data is available about the pathophysiological mechanisms of unexplained dyspnea and their clinical meaning. Consecutive patients with unexplained dyspnea underwent prospective standardized cardiopulmonary exercise testing with echocardiography (CPETecho). Patients were grouped as having normal exercise capacity (peak VO2 > 80% with respiratory exchange [RER] > 1.05), reduced exercise capacity (peak VO2 ≤ 80% with RER > 1.05), or a submaximal exercise test (RER ≤ 1.05). From 307 patients, 144 (47%) had normal and 116 (38%) reduced exercise capacity, and 47 (15%) had a submaximal exercise test. Patients with reduced versus normal exercise capacity had significantly more mechanisms for unexplained dyspnea (2.3±1.0 vs 1.5±1.0, respectively; p<0.001). Exercise PH (42%), low heart rate reserve (51%), low stroke volume reserve (38%), low diastolic reserve (18%), and peripheral muscle limitation (17%) were most common. Patients with more mechanisms for dyspnea displayed poorer peak VO2 and had an increased risk for cardiovascular hospitalization (p=0.002). Patients with unexplained dyspnea display multiple coexisting mechanisms for exercise intolerance, which relate to the severity of exercise limitation and risk of subsequent cardiovascular hospitalizations.

Exercise-Induced Pulmonary Hypertension Is Associated with High Cardiovascular Risk in Patients with HIV.

Background and Aim: Pulmonary hypertension (PH) at rest can be preceded by the onset of exercise-induced PH (ExPH). We investigated its association with the cardiovascular (CV) risk score in patients with human immunodeficiency virus (HIV). Methods: In 46 consecutive patients with HIV with low (n = 43) or intermediate (n = 3) probability of resting PH, we evaluated the CV risk score based on prognostic determinants of CV risk. Diagnosis of ExPH was made by cardiopulmonary exercise test (CPET) and exercise stress echocardiogram (ESE). Results: Twenty-eight % (n = 13) of the enrolled patients had ExPH at both CPET and ESE, with good agreement between the two methods (Cohen's kappa = 0.678). ExPH correlated directly with a higher CV score (p < 0.001). Patients with a higher CV score also had lower CD4+ T-cell counts (p = 0.001), a faster progression to acquired immunodeficiency syndrome (p < 0.001), a poor immunological response to antiretroviral therapy (p = 0.035), higher pulmonary vascular resistance (p = 0.003) and a higher right atrial area (p = 0.006). Conclusions: Isolated ExPH is associated with a high CV risk score in patients with HIV. Assessment of ExPH may better stratify CV risk in patients with HIV.

Exercise-induced pulmonary hypertension in HFpEF and HFrEF: Different pathophysiologic mechanism behind similar functional impairment.

AIMS: Pathophysiological mechanisms behind cardio-pulmonary impairment in heart failure (HF) with reduced (HFrEF) and preserved (HFpEF) ejection fraction are likely different. We analysed them using combined cardiopulmonary-exercise stress echocardiography (CPET-ESE). METHODS: We matched 1:1 subjects with HFrEF (n = 90) and HFpEF (n = 90) for age, sex, body mass index (BMI), peak oxygen consumption, and minute ventilation/carbon dioxide production slope. All patients underwent a symptom-limited graded ramp bicycle CPET-ESE compared with 40 age-, sex- and BMI-matched healthy controls. RESULTS: During a median follow-up of 25 months, we observed 22 deaths and 80 HF hospitalisations, with similar distribution between HFpEF and HFrEF. Compared with HFrEF, HFpEF had a higher prevalence of metabolic syndrome (p = 0.02) with higher levels of high-sensitivity C-reactive protein and uric acid (p < 0.01). The multipoint mean pulmonary artery pressure/cardiac output (mPAP/CO) slope showed equally increased values in HFrEF and HFpEF (3.5 ± 1.8 and 3.7 ± 1.5 mmHg/L/min) compared with controls (1.8 ± 1.1 mmHg/L/min; p < 0.0001). During exercise, HFpEF displayed more adverse interaction of right ventricle-pulmonary artery (RV-PA; tricuspid annular plane systolic excursion/systolic pulmonary artery pressure: 0.40 ± 0.2 vs 0.47 ± 0.2 mm/mmHg in HFrEF; p < 0.01) and left atrium-left ventricle (LA-LV; LA reservoir strain/LV global longitudinal strain: 1.5 ± 0.8 vs 2.2 ± 1.1 in HFrEF; p < 0.01). The latter were independent predictors of mPAP/CO slope, along with hs-CRP (adjusted R2: 0.21; p < 0.0001). CONCLUSION: Despite similar disease severity, HFpEF and HFrEF show different pathophysiological mechanisms. HFpEF is characterised by a worse LA-LV and RV-PA interaction than HFrEF, with more prevalent low-grade systemic inflammation. In HFpEF, these features may have a role in exercise-induced pulmonary hypertension.

Impact of Exercise-Induced Pulmonary Hypertension on Right Ventricular Function and on Worsening of Cardiovascular Risk in HIV Patients.

Background and Aim: Exercise-induced pulmonary hypertension (ExPH) predicts clinical outcomes, such as all-cause mortality and cardiovascular (CV) hospitalizations, in patients with dyspnea on effort. We investigated its prognostic significance in human immunodeficiency virus (HIV)-affected patients. Methods: In 52 consecutive HIV patients with either low (n = 47) or intermediate probability (n = 5) of PH at rest, we evaluated­at time 0 and after 2 years­the prognostic determinants of CV risk, according to the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) Guidelines. Patients were classified with or without ExPH at stress echocardiography (ESE) and cardiopulmonary exercise test (CPET). We then related ExPH at time 0 with clinical worsening (CV risk score increase >20% after 2 years). Results: Right ventricle (RV) systolic function was significantly reduced in patients with ExPH compared to those without ExPH at CPET. This also occurred in patients with intermediate/high probability compared to those with low probability of ExPH at ESE. The former exhibited worse values of TAPSE and FAC (p < 0.001 and p = 0.01, respectively). A significantly higher proportion of patients with ExPH (CPET) or with intermediate/high probability of ExPH (ESE) had higher sPAP (p < 0.001), mPAP (p = 0.004) and higher TRV (p = 0.006), as well as higher right atrial area (p < 0.001) and indexed right atrial volume (p = 0.004). Total pulmonary vascular resistance (expressed by the ratio between TRV and the velocity-time integral at the level of the right ventricular outflow tract) was higher both in patients with ExPH and in those with intermediate/high probability of ExPH (p < 0.001). Patients with intermediate/high probability of ExPH at ESE showed a trend (p = 0.137) towards clinical worsening compared to those with low probability of ExPH. No patients with low probability of ExPH had a >20% increased CV risk score after 2 years. We found an association between higher NT-proBNP and the presence or intermediate/high probability of ExPH after 2 years (p = 0.048 at CPET, p = 0.033 at ESE). Conclusions: The assessment of ExPH may predict a trend of increasing CV risk score over time. If confirmed at a longer follow-up, ExPH could contribute to better risk stratification in HIV patients.

Exercise-induced pulmonary hypertension in HIV patients: Association with poor clinical and immunological status.

BACKGROUND AND AIM: Exercise-induced pulmonary hypertension (Ex-PH) may represent the earliest sign of pulmonary arterial hypertension (PAH) in human immunodeficiency virus (HIV) patients. We investigated its association with clinical and immunological status, virologic control, and response to antiviral therapy. METHODS: In 32 consecutive HIV patients with either low (n = 29) or intermediate probability (n = 3) of PH at rest, we evaluated the association of isolated ExPH with: time to HIV diagnosis; CD4+ T-cell count; clinical progression to acquired immunodeficiency syndrome (AIDS); development of resistance to antiretroviral therapy (ART); HIV RNA levels; time to beginning of ART; current use of protease inhibitors; combination of ART with boosters (ritonavir or cobicistat); immuno-virologic response to ART; and ART discontinuation. Isolated ExPH at stress echocardiography (ESE) was defined as absence of PH at rest and systolic pulmonary arterial pressure (sPAP) >45 mmHg or a >20 mmHg increase during low-intensity exercise cardiac output (<10 L/min). RESULTS: In our cohort, 22% (n = 7) of the enrolled population developed ExPH which was inversely related to CD4+ T-cell count (p = 0.047), time to HIV diagnosis (p = 0.014) and time to onset of ART (p = 0.041). Patients with ExPH had a worse functional class than patients without ExPH (p < 0.001). ExPH and AIDS showed a trend (p = 0.093) to a direct relationship. AIDS patients had a higher pulmonary vascular resistance compared to patients without ExPH (p = 0.020) at rest echocardiography. CONCLUSIONS: The presence of isolated ExPH associates with a worse clinical status and poor immunological control in HIV patients. Assessment of ExPH by ESE may help identify subgroups of HIV patients with a propensity to develop subclinical impairment of pulmonary circulation following poor control of HIV infection.

Impact of Prosthesis-Patient Mismatch on Hemodynamics During Exercise in Patients With Aortic Stenosis After Transcatheter Aortic Valve Implantation With a Balloon-Expandable Valve.

BACKGROUND: There is no evidence of hemodynamic performance during exercise in patients with aortic stenosis (AS) after transcatheter aortic valve implantation (TAVI). This study aimed to investigate the changes in kinematic hemodynamics during exercise and determine the impact of prosthesis-patient mismatch (PPM) on the hemodynamics of transcatheter heart valves using exercise stress echocardiography (ESE) in AS patients after TAVI. METHODS AND RESULTS: This study enrolled 77 consecutive patients (mean age 82 ± 5 years, 50.6% male) who underwent ESE 3-6 months after TAVI with a balloon-expandable valve. The effective orifice area index at rest was significantly correlated with the mean pressure gradient (PG) during exercise (p <0.001). The patients were divided into two groups according to the presence of PPM (PPM and non-PPM groups). During exercise, the patients with PPM had a higher left ventricular ejection fraction (74.6 ± 6.1% vs. 69.7 ± 9.6%, p = 0.048), a lower stroke volume index (47.2 ± 14.0 ml/m2 vs. 55.6 ± 14.5 ml/m2, p = 0.037), a significantly higher mean transvalvular PG (21.9 ± 9.1 mmHg vs. 12.2 ± 4.9 mmHg, p = 0.01) and an increased mean PG from rest to exercise (5.7 ± 3.5 mmHg vs. 2.3 ± 2.8 mmHg, p <0.001) compared with patients without PPM. Patients with PPM had a higher pulmonary artery systolic pressure (SPAP) during exercise (57.3 ± 13.8 mmHg vs. 49.7 ± 10.9 mmHg, p = 0.021) and a higher incidence of exercise-induced pulmonary hypertension (43.8 vs. 15.0%, p = 0.037) than patients without PPM. PPM was strongly associated with exercise-induced pulmonary hypertension (hazard ratio: 3.570, p = 0.013). CONCLUSIONS: AS patients with PPM after TAVI showed a disproportionate increase in the transvalvular PG and SPAP during exercise, and PPM was associated with exercise-induced pulmonary hypertension.

Under Pressure: Right Heart Catheterization and Provocative Testing for Diagnosing Pulmonary Hypertension.

Pulmonary hypertension (PH) is a heterogenous disorder involving multiple pathophysiological processes that ultimately affect the vasculature within the lungs. Right heart catheterization (RHC) continues to be the benchmark for diagnosing PH. The use of provocation techniques during RHC can help sub-characterize the type of PH and thus assist in developing appropriate treatment strategies for the management of each PH subtype. This review examines proven and novel approaches for evaluating the pulmonary vasculature during RHC and aspires to provide an accurate, clinically relevant framework for using RHC to diagnose and manage PH. Further improvement in standardized protocols will help optimize the application of RHC in patients with PH.

Isolated Exercise-Induced Pulmonary Hypertension Associates with Higher Cardiovascular Risk in Scleroderma Patients.

BACKGROUND AND AIM: Isolated exercise-induced pulmonary hypertension (ExPH) associates with cardiovascular (CV) events in patients with left heart disease. We investigated its prognostic significance in scleroderma patients at risk for pulmonary arterial hypertension (PAH). METHODS: In 26 consecutive scleroderma female patients with either low (n = 13) or intermediate probability (n = 13) of pulmonary hypertension (PH) at rest, we evaluated, both at time 0 and 1 year, prognostic determinants of CV risk: onset or progression of heart failure/syncope; worsening of functional class; functional performance at the 6-minute walking test and at cardiopulmonary exercise test; right atrial area; and pericardial effusion. We assigned a severity score 1-3 to each prognostic determinant, derived an overall CV risk score, and its 0-1 year change. Isolated ExPH during the cardiopulmonary exercise test (CPET) was defined as absence of PH at rest, reduced peak VO2, VE/VCO2 >30 at anaerobic threshold, reduced O2 pulse, and ΔVO2/ΔW <9 mL/min/W. We then correlated ExPH at time 0 with clinical worsening (risk score increase >20% after 1 year). RESULTS: ExPH was strongly associated with clinical worsening compared to patients without ExPH (p = 0.005). In patients without ExPH, none had > 20% increased CV risk score after 1 year. Conversely, about 50% of patients with ExPH had such an increase, suggesting a worsening of prognosis. CONCLUSIONS: Isolated ExPH associates with higher cardiovascular risk and thus clinical worsening in scleroderma patients. The assessment of ExPH by CPET can thus contribute to a better risk stratification and the planning of a more adequate follow-up.

Prevalence, determinants, and prognostic significance of exercise-induced pulmonary hypertension in patients with hypertrophic cardiomyopathy.

Exercise-induced pulmonary hypertension (EIPH) is associated with worse outcomes in patients with heart failure or valvular heart disease. However, little is known regarding the implications of EIPH in hypertrophic cardiomyopathy (HCM) patients. We retrospectively reviewed data of consecutive HCM patients who underwent clinically indicated exercise echocardiography using a semi-supine bicycle ergometer at our hospital. EIPH was defined as pulmonary artery systolic pressure ≥ 60 mmHg during exercise. The incidences of HCM-related mortality and HCM-related morbidity during follow-up period were evaluated. Of 42 patients (mean age 59 ± 21 years; 4 with resting obstruction, 19 with provoked obstruction, and 19 without obstruction), 16 (38%) developed EIPH. Patients with EIPH had significantly longer resting E wave deceleration time (271 ± 116 vs. 213 ± 66 ms; P = 0.04), higher resting pulmonary artery systolic pressure (35 ± 6 vs. 31 ± 5 mmHg; P = 0.04), and higher B-type natriuretic peptide level (283 [222, 465] vs. 142 [54, 423] pg/ml; P = 0.04) than those without EIPH. Kaplan-Meier curve analysis demonstrated that EIPH was significantly associated with HCM-related morbidity (log-rank; P = 0.01). In Cox regression analysis, EIPH was a significant predictor of HCM-related morbidity (hazard ratio: 5.98, 95% confidence interval 1.36-41.07; P = 0.02). In conclusion, EIPH was documented in about one-third of HCM patients. EIPH was a significant predictor of HCM-related morbidity in patients with HCM.

Significant Clinical Indexes of Exercise-Induced Pulmonary Hypertension in Patients With Connective Tissue Disease.

Background: Pulmonary hypertension (PH) is an important cause of morbidity in patients with connective tissue disease (CTD), and an early stage of PH could present as exercise-induced PH (EIPH). This study investigated the significant clinical indexes of EIPH in patients with CTD. Methods and Results: We enrolled 63 patients with CTD who did not have PH at rest. All patients underwent the 6-min walk test (6MWT), and systolic pulmonary artery pressure (SPAP) was evaluated on echocardiography before and after 6MWT. EIPH was defined as SPAP ≥40 mmHg after 6 WMT. Thirty-five patients had EIPH. On univariate logistic analysis, SPAP at rest, log brain natriuretic peptide (BNP), vital capacity (VC), and forced expiratory volume in 1 s (FEV1.0) were significantly correlated with EIPH. On multiple logistic analysis, SPAP at rest and VC were independent predictors of EIPH, whereas FEV1.0 and log BNP were not significantly associated with EIPH. The area under the receiver operating characteristics curve between EIPH and BNP, SPAP at rest, VC or FEV1.0 was 0.67, 0.76, 0.74, and 0.75, respectively. Conclusions: SPAP at rest and respiratory function, especially VC, could be independent predictors of EIPH in patients with CTD.

Exercise-Induced Pulmonary Hypertension: Translating Pathophysiological Concepts Into Clinical Practice.

Exercise stress testing of the pulmonary circulation for the diagnosis of latent or early-stage pulmonary hypertension (PH) is gaining acceptance. There is emerging consensus to define exercise-induced PH by a mean pulmonary artery pressure > 30 mm Hg at a cardiac output < 10 L/min and a total pulmonary vascular resistance> 3 Wood units at maximum exercise, in the absence of PH at rest. Exercise-induced PH has been reported in association with a bone morphogenetic receptor-2 gene mutation, in systemic sclerosis, in left heart conditions, in chronic lung diseases, and in chronic pulmonary thromboembolism. Exercise-induced PH is a cause of decreased exercise capacity, may precede the development of manifest PH in a proportion of patients, and is associated with a decreased life expectancy. Exercise stress testing of the pulmonary circulation has to be dynamic and rely on measurements of the components of the pulmonary vascular equation during, not after exercise. Noninvasive imaging measurements may be sufficiently accurate in experienced hands, but suffer from lack of precision, so that invasive measurements are required for individual decision-making. Exercise-induced PH is caused either by pulmonary vasoconstriction, pulmonary vascular remodeling, or by increased upstream transmission of pulmonary venous pressure. This differential diagnosis is clinical. Left heart disease as a cause of exercise-induced PH can be further ascertained by a pulmonary artery wedge pressure above or below 20 mm Hg at a cardiac output < 10 L/min or a pulmonary artery wedge pressure-flow relationship above or below 2 mm Hg/L/min during exercise.

Hemodynamic Mechanisms of Exercise-Induced Pulmonary Hypertension in Patients with Lymphangioleiomyomatosis: The Role of Exercise Stress Echocardiography.

BACKGROUND: The pathogenesis of pulmonary hypertension (PH) in lymphangioleiomyomatosis (LAM) has not yet been completely clarified. The aim of this study was to conduct a noninvasive evaluation of the main hemodynamic mechanisms of exercise-induced PH in patients with LAM, assessed using exercise stress echocardiography. METHODS: Fifteen patients with LAM (mean age, 47 ± 13 years; all women) without resting PH were enrolled in a prospective single-center study and compared with 15 healthy female control subjects (mean age, 45.2 ± 8 years; P = .65). A complete echocardiographic study with Doppler tissue imaging was performed at baseline and during semisupine symptom-limited exercise testing to evaluate (1) left ventricular systolic and diastolic function, (2) right ventricular contractile function, (3) estimated pulmonary capillary wedge pressure, (4) estimated systolic and mean pulmonary artery pressure, and (5) estimated pulmonary vascular resistance. RESULTS: Compared with healthy control subjects, patients with LAM during exercise showed echocardiographic signs of right ventricular overload and right ventricular systolic dysfunction and significant increases in mean pulmonary artery pressure (14.4 ± 6.5 vs 4.2 ± 3.1 mm Hg, P < .0001), pulmonary vascular resistance (+68.3 ± 42.1 vs -0.1 ± 18.3 dyne-sec/cm5, P < .0001), and, unexpectedly, pulmonary capillary wedge pressure (+8.3 ± 5.3 vs -0.5 ± 1.3 mm Hg, P < .0001). CONCLUSIONS: Exercise-induced PH in patients with LAM could be related not only to hypoxic pulmonary vascular vasoconstriction during exercise (precapillary PH) but also to a significant exercise-induced increase in estimated pulmonary capillary wedge pressure, probably secondary to diastolic dysfunction (postcapillary PH).

Exercise-induced pulmonary hypertension by stress echocardiography: Prevalence and correlation with right heart hemodynamics.

OBJECTIVES: The aim of this study was to determine the prevalence of exercise-induced pulmonary hypertension (EIPH) in consecutive subjects referred for stress echocardiography for chest pain or shortness of breath and correlate echocardiographic diagnosis of EIPH with hemodynamics at right heart catheterization (RHC). BACKGROUND: Elevated pulmonary pressure can lead to significant morbidity and mortality. EIPH by ehocardiography has been described in patients with connective tissue disease. It's prevalence in the setting of routine clinically indicated stress echocardiography unknown. METHODS: In a retrospective analysis of 4068 consecutive stress subjects undergoing stress echocardiography, 479 subjects with EIPH were identified. All 479 subjects with EIPH were compared to 479 age and sex matched subjects with normal pulmonary artery pressures post exercise. EIPH was defined as PASP>50mmHg or peak tricuspid regurgitation velocity>3.2m/s. Of 100 patients with EIPH who underwent RHC we identified variables which predicted abnormal hemodynamic findings on RHC. RESULTS: The prevalence of EIPH in subjects referred for stress echocardiography was 11.7%. A greater proportion of subjects with EIPH were obese or had lung disease or connective tissue disease. Of 100 subjects who underwent RHC, 65 had abnormal results. Age>55years (OR 5.1, p<0.01]) or dilated left atrium (OR 4.4, p=0.02]) were independently associated with abnormal right heart hemodynamics. CONCLUSIONS: The results demonstrate that 11.7% of patients undergoing clinically indicated stress echocardiography have EIPH. Of those who underwent RHC abnormal hemodynamics were significantly associated with a dilated left atrium or age older than 55years.