Cardiopulmonary exercise testing in the assessment of pulmonary hypertension

Simplified risk stratification based on cardiopulmonary exercise test: A Spanish two-center experience

A simplified 4-strata risk stratification approach based on three variables is widespread in pulmonary arterial hypertension (PAH) at follow-up. This study aimed to assess the impact of replacing the 6-min walk test (6MWT) with the peak 02 uptake evaluated by the cardiopulmonary exercise test (CPET) on risk stratification by this scale. We included 180 prevalent patients with PAH from two reference hospitals in Spain, followed up between 2006 and 2022. Patients were included if all the variables of interest were available within a 3-month period on the Spanish Registry of Pulmonary Arterial Hypertension (REHAP): functional class (FC); NT-proBNP; 6MWT; and CPET. The original 4-strata model (NT-proBNP, 6MWT, FC) identified most patients at low or intermediate-low risk (36.7% and 51.1%, respectively). Notably, the modified scale (NT-proBNP, CPET, FC) improved the identification of patients at intermediate-high risk up to 18.9%, and at high risk up to 1.1% in comparison with the previous 12.2% and 0.0% in the original scale. This new model increased the number of patients correctly classified into higher-risk strata (positive NRI of 0.06), as well as classified more patients without events in lower-risk strata (negative NRI of 0.04). The proposed score showed a slightly superior prognostic capacity compared with the original model (Harrel's C-index 0.717 vs. 0.709). Using O2 uptake instead of distance walked in the 6MWT improves the identification of high-risk patients using the 4-strata scale. This change could have relevant prognostic implications and lead to changes in the specific treatment of PAH.

Cardiopulmonary Exercise Testing, Rehabilitation, and Exercise Training in Postpulmonary Embolism

Long-term exercise intolerance and functional limitations are common after an episode of acute pulmonary embolism (PE), despite 3 to 6 months of anticoagulation. These persistent symptoms are reported in more than half of the patients with acute PE and are referred as "post-PE syndrome." Although these functional limitations can occur from persistent pulmonary vascular occlusion or pulmonary vascular remodeling, significant deconditioning can be a major contributing factor. Herein, the authors review the role of exercise testing to elucidate the mechanisms of exercise limitations to guide next steps in management and exercise training for musculoskeletal deconditioning.

Distinguishing exercise intolerance in early-stage pulmonary hypertension with invasive exercise hemodynamics: Rest VE /VCO2 and ETCO2 identify pulmonary vascular disease

BACKGROUND

Among subjects with exercise intolerance and suspected early-stage pulmonary hypertension (PH), early identification of pulmonary vascular disease (PVD) with noninvasive methods is essential for prompt PH management.

HYPOTHESIS

Rest gas exchange parameters (minute ventilation to carbon dioxide production ratio: VE /VCO2 and end-tidal carbon dioxide: ETCO2 ) can identify PVD in early-stage PH.

METHODS

We conducted a retrospective review of 55 subjects with early-stage PH (per echocardiogram), undergoing invasive exercise hemodynamics with cardiopulmonary exercise test to distinguish exercise intolerance mechanisms. Based on the rest and exercise hemodynamics, three distinct phenotypes were defined: (1) PVD, (2) pulmonary venous hypertension, and (3) noncardiac dyspnea (no rest or exercise PH). For all tests, *p < .05 was considered statistically significant.

RESULTS

The mean age was 63.3 ± 13.4 years (53% female). In the overall cohort, higher rest VE /VCO2 and lower rest ETCO2 (mm Hg) correlated with high rest and exercise pulmonary vascular resistance (PVR) (r ~ 0.5-0.6*). On receiver-operating characteristic analysis to predict PVD (vs. non-PVD) subjects with noninvasive metrics, area under the curve for pulmonary artery systolic pressure (echocardiogram) = 0.53, rest VE /VCO2  = 0.70* and ETCO2  = 0.73*. Based on this, optimal thresholds of rest VE /VCO2  > 40 mm Hg and rest ETCO2  < 30 mm Hg were applied to the overall cohort. Subjects with both abnormal gas exchange parameters (n = 12, vs. both normal parameters, n = 19) had an exercise PVR 5.2 ± 2.6* (vs. 1.9 ± 1.2), mPAP/CO slope with exercise 10.2 ± 6.0* (vs. 2.9 ± 2.0), and none included subjects from the noncardiac dyspnea group.

CONCLUSIONS

In a broad cohort of subjects with suspected early-stage PH, referred for invasive exercise testing to distinguish mechanisms of exercise intolerance, rest gas exchange parameters (VE /VCO2  > 40 mm Hg and ETCO2  < 30 mm Hg) identify PVD.

Factors related to instrumental activities of daily living in persons with chronic thromboembolic pulmonary hypertension

Instrumental activities of daily living (IADL) are significantly related to quality of life and mortality among individuals with heart disease. However, few reports have examined IADL in persons with chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to clarify factors related to IADL in persons with CTEPH. This retrospective, observational study enrolled 163 persons with CTEPH (mean ± standard deviation age = 65 ± 13 years; 68% female) admitted to the Department of Cardiology at Keio University Hospital between January 2015 and July 2019. The Frenchay Activities Index (FAI) was used to assess IADL. Age, sex, body mass index, World Health Organization functional class (WHO-FC), cardiac function (mean pulmonary arterial pressure, mean right atrial pressure, pulmonary capillary wedge pressure, and cardiac index), pulmonary function (percentage vital capacity, percentage forced expiratory volume in 1 s, diffusion capacity of carbon monoxide (DLCO)/alveolar volume (VA)), physical function (knee extension strength and walking speed), and 6-min walking distance (6MWD) were assessed. Multiple regression analysis was performed to identify factors significantly associated with FAI. Mean FAI was 25 ± 8. Univariate analysis showed that sex, WHO-FC, DLCO/VA, walking speed, and 6MWD were correlated with FAI. Multiple regression analysis showed that 6MWD (sβ = 0.338, 95% CI 0.014–0.034, p < .001), sex (sβ = 0.268, 95% CI 2.238–7.165, p < .001), and DLCO/VA (sβ = 0.257, 95% CI 1.011–3.528, p < .001) were significantly correlated with FAI (R² = 0.261). IADL were associated with exercise tolerance, sex, and DLCO/VA in persons with CTEPH. In the future, more details of IADL are expected to be clarified by analyzing individual components of IADL and investigating social background characteristics, including living environment.

Lung function in relation to six-minute walk test in pulmonary hypertension

Background: Pulmonary hypertension (PH) is a progressive disorder of the pulmonary circulation, associated with diverse medical conditions. Exercise limitation is the most prominent symptom in PH. Exercise capacity, commonly assessed through a six-minute walk test (6MWT), correlates with both functional status and survival in PH. Few studies have analysed the relation between respiratory function and exercise limitation. Therefore, we investigated the relationship between resting pulmonary function, exercise capacity, and exertional desaturation, assessed through the 6MWT, in unselected PH patients.

Methods: Fifty consecutive patients with PH diagnosis, referred for pulmonary function testing (lung volume, spirometry, and diffusing capacity for carbon monoxide (DLCO)) and 6MWT, were recruited at Molinette University Hospital, Turin.

Results: The majority of the patients (54%) had PH due to left heart disease. Airway obstruction (FEV₁/VC-ratio < 0.7) was found in 46% of the patients and they performed significantly worse in the 6MWT than unobstructed patients (307 m vs. 377 m). Patients with PH due to left heart disease also performed significantly poorer 6MWT when airway obstruction was present (305 m vs. 389 m). Twenty-two patients (44%) presented exertional desaturation upon 6MWT. Lower DLCO divided by the alveolar volume (DLCO/VA), FEV₁/VC-ratios and resting PaO₂-values were significantly correlated with exertional desaturation after adjustments for age, sex, BMI, and smoking habits. DLCO/VA was the main determinant of exertional desaturation in a stepwise regression model.

Conclusions: Spirometric parameters of airway obstruction were related to walk distance and exercise-induced desaturation in PH patients. This suggests a place for spirometry in clinical monitoring of PH patients.

Intensity and quality of exertional dyspnoea in patients with stable pulmonary hypertension

Dynamic hyperinflation is observed during exercise in 60% of patients with clinically stable pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), intensifying exertional dyspnoea. The impact of dynamic changes in respiratory mechanics during exercise on qualitative dimensions of dyspnoea in these patients has not been evaluated.

26 patients (PAH n=17; CTEPH n=9) performed an incremental symptom-limited cycle exercise test. Minute ventilation (V′E), breathing pattern, operating lung volumes and dyspnoea intensity were assessed throughout exercise. Dyspnoea quality was serially assessed during exercise using a three-item questionnaire (dyspnoea descriptors). The inflection point of tidal volume (VT) relative to V′E was determined for each incremental test. Changes in inspiratory capacity during exercise defined two groups of patients: hyperinflators (65%) and non-hyperinflators (35%). Multidimensional characterisation of dyspnoea was performed after exercise using the Multidimensional Dyspnea Profile.

In hyperinflators, inspiratory capacity decreased progressively throughout exercise by 0.36 L, while remaining stable in non-hyperinflators. The “work/effort” descriptor was most frequently selected throughout exercise in both types of patients (65% of all responses). At the VT/V′E inflection, work/effort plateaued while “unsatisfied inspiration” descriptors became selected predominantly only in hyperinflators (77% of all responses). In the affective domain, the emotion most frequently associated with dyspnoea was anxiety.

In pulmonary hypertension patients who develop hyperinflation during exercise, dyspnoea descriptors referring to unsatisfied inspiration become predominant following the VT/V′E inflection. As these descriptors are generally associated with more negative emotional experiences, delaying or preventing the VT/V′E inflection may have important implications for symptom management in patients with pulmonary hypertension.

Effects of home-based exercise training on functional outcomes and quality of life in patients with pulmonary hypertension: A randomized clinical trial

Objectives

The objective of this study was to assess the effects of home-based exercise training (HBET) on function and quality of life (QoL) in patients with pulmonary hypertension (PH).

Methods

A prospective, nonblinded, randomized clinical trial was carried out on 84 medically stable patients with PH belonging to any functional class or etiology and of either sex. Patients were randomized to either standard care or HBET. Both groups also received education using the Pulmonary Hypertension Manual (PulHMan). Outcomes included functional capacity from 6-min walk distance (6MWD), QoL using the Medical Outcomes Survey Short Form – 36, functional class (FC), and right heart indices (right ventricular systolic pressure [RVSP] and tricuspid annular plane systolic excursion [TAPSE]) and were assessed at entry and after 12 weeks.

Results

HBET improved 6MWD by 48.5 m and 13 m in the experimental and control groups, respectively (p < 0.001). QoL showed statistical improvements after HBET between the groups for the physical and mental components and for the various subdomains (except body pain). Furthermore, FC improved by one grade with HBET (p < 0.001).

Conclusion

HBET program improved functional capacity, QoL, and FC in patients with PH.

Characteristics of cardiopulmonary exercise testing of patients with borderline mean pulmonary artery pressure

BACKGROUND

Pulmonary hypertension patients with mean pulmonary artery pressure (mPAP) ≥ 25 mm Hg had impaired cardiopulmonary exercise testing (CPET). Borderline mean pulmonary pressures (boPAP; 21-24 mm Hg) represent early pulmonary vasculopathy. The CPET characteristics of boPAP are a matter of discussion. We aimed to determine the CPET profile of such borderline hemodynamics.

METHODS

A matched case-control study was conducted on consecutive boPAP patients at the Shanghai Pulmonary Hospital between Jan 2012 and Jan 2017. Hemodynamics, echocardiography, the pulmonary function test (PFT) and CPET parameters were compared between boPAP patients and normal mPAP patients which were matched 1:1 by sex and age. Conditional logistic regression analysis was performed to determine the efficacy of CPET in detecting boPAP.

RESULTS

A total of 48 patients underwent RHC and CPET (24 Normal, 24 boPAP). There were no differences in the demographics, echocardiography and PFT. BoPAP patients had significantly decreased VO₂ at the anaerobic threshold and peak VO₂ /kg (858.4 ± 246.5 mL/min vs 727.9 ± 228.0 mL/min, P = 0.037; 21.1 ± 6.4 mL/min/kg vs. 15.5 ± 5.6 mL/min/kg, P = 0.001, respectively). Significant differences were not observed in ventilation efficiency. A trend of impaired oxygen pulse and submaximal exercise tolerance were observed in boPAP patients. Conditional logistical regression analysis revealed the risk of boPAP increased by 2.493 (95% confident interval: 1.388 to 4.476, P = 0.002) with every 5 mL/min/kg decrease in peak VO₂ /kg.

CONCLUSIONS

Patients with boPAP have a greater prevalence of exercise intolerance, a trend of impaired oxygen pulse and submaximal exercise tolerance.

Safe and effective exercise training for patients with pulmonary arterial hypertension: putting current evidence into clinical practice

INTRODUCTION

While there have been significant advances in the medical treatment of pulmonary arterial hypertension (PAH), life expectancy, and quality of life remain reduced in this disease. Strenuous exercise may be hazardous for PAH patients; however, several relatively small trials have confirmed that exercise training programs can be used safely and effectively as adjunctive treatment for selected patients. The use of exercise training is now recommended in consensus international PAH treatment algorithms; however, there is no published guideline detailing how this intervention should be carried out. Areas covered: This review describes the evidence available and evaluates its applicability to 'real life' clinical practice. The limitations of current evidence are acknowledged, and we discuss how the existing data can be applied to management of PAH patients in Australia, New Zealand, and countries with similar healthcare systems. Recommendations for PAH exercise training are proposed including patient selection, program structure and duration, training modalities, training intensity, supervision, monitoring, safety precautions, and outcome assessments. Expert commentary: It is recognized that knowledge gaps remain and further research is required into physiological mechanisms associated with improved exercise capacity, optimal outpatient exercise regimen, durability of benefit, and whether there is any disease-modifying effect or impact on long-term prognosis.

Exercise intolerance in pulmonary hypertension: mechanism, evaluation and clinical implications

INTRODUCTION

Exercise intolerance in pulmonary hypertension (PH) is a major factor affecting activities of daily living and quality of life. Evaluation strategies (i.e., non-invasive and invasive tests) are integral to providing a comprehensive assessment of clinical and functional status. Despite a growing body of literature on the clinical consequences of PH, there are limited studies discussing the contribution of various physiological systems to exercise intolerance in this patient population.

AREAS COVERED

This review, through a search of various databases, describes the physiological basis for exercise intolerance across the various PH etiologies, highlights the various exercise evaluation methods and discusses the rationale for exercise training amongst those diagnosed with PH. Expert commentary: With the growing importance of evaluating exercise capacity in PH (class 1, Level C recommendation), understanding why exercise performance is altered in PH is crucial. Thus, the further study is required for better quality evidence in this area.

Effects of Exercise Training on Exercise Capacity in Pulmonary Arterial Hypertension: A Systematic Review of Clinical Trials

BACKGROUND

Pulmonary arterial hypertension (PAH) causes profound functional limitations and poor quality of life. Yet, there is only a limited literature available on the role of exercise training. This paper systematically reviews the effects of exercise training on exercise capacity in PAH.

METHODS

A systematic search of databases (PubMed, CINAHL, CENTRAL, Web of Science and PEDRo) was undertaken for English language articles published between 1(st) January 1980 and 31(st) March 2015. Quality rating for all articles was done using the Downs and Black scoring system.

RESULTS

Fifteen articles of good (n=4), moderate (n=6) and poor (n=5) quality were included in the review. Exercise interventions included aerobic, resistance, inspiratory muscle training or a combination, for 6-18 weeks. Improvements were seen in exercise capacity (six minute walk distance (6MWD) and peak VO2) by 17-96m and 1.1-2.1ml/Kg/min, functional class by one class and quality of life, with minimal adverse events.

CONCLUSIONS

There is evidence to recommend the use of exercise training as an adjunct to medical treatment in PAH. More clinical trials and research are required to assess the effects of different types of exercise programs in patients with PAH, while focussing on strong exercise endpoints to quantify the improvements seen with exercise training.

Association Between Hemodynamic Profile, Physical Capacity and Quality of Life in Pulmonary Hypertension

Background

No studies have described and evaluated the association between hemodynamics, physical limitations and quality of life in patients with pulmonary hypertension (PH) without concomitant cardiovascular or respiratory disease.

Objective

To describe the hemodynamic profile, quality of life and physical capacity of patients with PH from groups I and IV and to study the association between these outcomes.

Methods

Cross-sectional study of patients with PH from clinical groups I and IV and functional classes II and III undergoing the following assessments: hemodynamics, exercise tolerance and quality of life.

Results

This study assessed 20 patients with a mean age of 46.8 ± 14.3 years. They had pulmonary capillary wedge pressure of 10.5 ± 3.7 mm Hg, 6-minute walk distance test (6MWDT) of 463 ± 78 m, oxygen consumption at peak exercise of 12.9 ± 4.3 mLO2.kg-1.min-1 and scores of quality of life domains < 60%. There were associations between cardiac index (CI) and ventilatory equivalent for CO2 (r=-0.59, p <0.01), IC and ventilatory equivalent for oxygen (r=-0.49, p<0.05), right atrial pressure (RAP) and 'general health perception' domain (r=-0.61, p<0.01), RAP and 6MWTD (r=-0.49, p<0.05), pulmonary vascular resistance (PVR) and 'physical functioning' domain (r=-0.56, p<0.01), PVR and 6MWTD (r=-0.49, p<0.05) and PVR index and physical capacity (r=-0.51, p<0.01).

Conclusion

Patients with PH from groups I and IV and functional classes II and III exhibit a reduction in physical capacity and in the physical and mental components of quality of life. The hemodynamic variables CI, diastolic pulmonary arterial pressure, RAP, PVR and PVR index are associated with exercise tolerance and quality of life domains.

Pulmonary hypertension: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Pulmonary vascular dysfunction (PVD) precedes the onset of clinical signs and symptoms of pulmonary arterial hypertension (PAH). PAH is defined by the elevation of pulmonary arterial pressure, which often progresses to right ventricular (RV) dysfunction and failure. PAH affects subjects of all ages, and is associated with diverse medical conditions, most of which are rare. Several factors pose immediate challenges to the development of strategies for primary prevention of PAH, including: (1) the idiopathic or primary form of the disease is extremely rare, limiting screening practicality; (2) methods for the detection of preclinical PVD are currently not established; (3) the understanding of determinants of pulmonary vascular growth, structure, and function in normal and PAH states is insufficient; (4) relatively small numbers of "at-risk" subjects are available for long-term studies to accurately assess disease development; and (5) preventative therapies for PVD are lacking. Despite these limitations, leveraging known at-risk patient populations for study, as well as growing progress across multiple disciplines, ranging from systems biology to advanced and more sensitive functional imaging modalities, may facilitate the opportunity to significantly improve primary prevention research and implementation over the next decade.

Extended-release oral treprostinil for the treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by an increase in pulmonary vascular resistance ultimately resulting in progressive right heart failure. Although new specific treatments have demonstrated improvements in various end points including morbidity/mortality, prognosis remains unfavorable with an on-treatment yearly mortality rate of 10%. Due to complex delivery systems, the use of parenteral prostanoids has been limited to patients with advanced disease. While inhaled prostanoids have had little effect, an oral prostacyclin analog is a desired initial treatment for PAH patients. To that end, UT-15C was synthesized as a sustained-release tablet. FREEDOM-M in treatment-naïve PAH patients resulted in significant improvements of 6-min walk distance supporting the use of oral treprostinil as initial monotherapy in PAH patients with class II or III symptoms. A further study targeting patients on combination treatments is currently exploring a morbidity/mortality end point in a large patient population.

Impact of pulmonary hypertension on exercise performance in patients with interstitial lung disease undergoing evaluation for lung transplantation

BACKGROUND AND OBJECTIVE

Pulmonary hypertension (PH) is a known complication in patients with interstitial lung disease (ILD). Cardiopulmonary exercise testing (CPET) is an essential tool for the assessment of patients with cardiac and pulmonary diseases due to its prognostic and therapeutic implications. Few studies have evaluated the relationship between CPET response and mean pulmonary artery pressures (mPAP) in ILD. The purpose of the present study was to determine and compare the potential correlations between CPET, 6-min walk test (6MWT), pulmonary function testing (PFT) and PH in patients with ILD being evaluated for lung transplantation.

METHODS

The present study reviewed patients with ILD who received lung transplantations and had CPETs within 2 years before transplantation, right heart catheterizations, PFTs and 6MWTs within 4 months of CPET.

RESULTS

A total of 72 patients with ILD were analysed; 36% had PH. There were significant correlations between mPAP and CPET parameters in patients with PH; but mPAP had no impact on percent of predicted diffusion capacity of the lung for carbon monoxide or 6-min walk distance (6MWD). CPET parameters were able to detect differences between levels of severity of PH through the use of the ratio of minute ventilation to rate of carbon dioxide production (VE/VCO2) and the partial pressure of end-tidal carbon dioxide.

CONCLUSIONS

This is the first study that analyses 6MWD, PFT and CPET in patients with ILD awaiting lung transplantation with and without PH. The present study demonstrates the significant impact of PH on exercise capacity and performance in patients with ILD awaiting lung transplantation.

Impairment of pulmonary vascular reserve and right ventricular systolic reserve in pulmonary arterial hypertension

Background

Exercise capacity is impaired in pulmonary arterial hypertension (PAH). We hypothesized that cardiovascular reserve abnormalities would be associated with impaired hemodynamic response to pharmacological stress and worse outcome in PAH.

Methods

Eighteen PAH patients (p) group 1 NYHA class II/III and ten controls underwent simultaneous right cardiac catheterization and intravascular ultrasound at rest and during low dose-dobutamine (10 mcg/kg/min) with trendelenburg (DST). We estimated cardiac output (CO), pulmonary vascular resistance (PVR) and capacitance (PC), and PA elastic modulus (EM). We concomitantly measured tricuspid annular plane systolic excursion (TAPSE), RV myocardial peak systolic velocity (Sm) and isovolumic myocardial acceleration (IVA) in PAH patients. Based on the rounded mean + 2 SD of the increase in mPAP in our healthy control group during DST (2.8 + 1.8 mm Hg), PAH p were divided into two groups according to mean PA pressure (mPAP) response during DST, 1: ΔmPAP > 5 mm Hg and 2: ΔmPAP ≤ 5 mm Hg. Cardiovascular reserve was estimated as the change (delta, Δ) during DST compared with rest, including ΔmPAP with respect to ΔCO (ΔmPAP/ΔCO). All patients were prospectively followed up for 2 years.

Results

PAH p showed significant lower heart rate and CO increase than controls during DST, with a significant mPAP and pulse PAP increase and higher ΔmPAP/ΔCO (p < 0.05). Neither hemodynamic, IVUS and echocardiographic data were different between both PAH groups at rest. In group 1, DST caused a higher ΔEM, ΔmPAP/ΔCO, ΔPVR, and ΔTAPSE than group 2, with a lower IVA increase and a negative ΔSV (p < 0.05). TAPSE correlated with mPAP and RVP (p < 0.05) and, IVA and Sm correlated with CO (p < 0.05). ΔEM correlated with ΔmPAP and ΔIVA with ΔCO (p < 0.05). There were two deaths/pulmonary transplantations in group 1 and one death in group 2 during the follow-up (p > 0.05).

Conclusions

Pulmonary vascular reserve and RV systolic reserve are significantly impaired in patients with PAH. The lower recruitable cardiovascular reserve is significantly related to a worse hemodynamic response to DST and it could be associated with a poor clinical outcome.

A review of ongoing trials in exercise based rehabilitation for pulmonary arterial hypertension

Exercise based rehabilitation for patients with pulmonary arterial hypertension (PAH) is a new treatment option for these patients to improve their functional capacity and quality of life. Despite the benefits seen in cardiopulmonary rehabilitation in various other conditions, it has been underutilized for the patients with PAH. A review of currently registered ongoing trials on exercise training for patients with PAH from the World Health Organization International Clinical Trial Registry Platform was done using the key words "rehabilitation", "exercise training", "pulmonary artery hypertension" and "pulmonary hypertension" for a period of 10 years (2002-2012). The search revealed 57 registered trials in various trial registries from which seven met the inclusion criteria. The current studies are being carried out in Germany (n=4), Brazil (n=1), Australia (n=1) and India (n=1). This indicates a shift in focus from the only medical management to the rehabilitation and long term care for patients with PAH.

Right ventricular dysfunction in chronic lung disease

Right ventricular (RV) dysfunction arises in chronic lung disease when chronic hypoxemia and disruption of pulmonary vascular beds increase ventricular afterload. RV dysfunction is defined by hypertrophy with preserved myocardial contractility and cardiac output. RV hypertrophy seems to be a common complication of chronic and advanced lung disease. RV failure is rare, except during acute exacerbations of chronic lung disease or when multiple comorbidities are present. Treatment is targeted at correcting hypoxia and improving pulmonary gas exchange and mechanics. There are no data supporting the use of pulmonary hypertension-specific therapies for patients with RV dysfunction secondary to chronic lung disease.

Heart rate recovery in pulmonary arterial hypertension: relationship with exercise capacity and prognosis

BACKGROUND

Delayed postexercise heart rate recovery (HRR) has been associated with disability and poor prognosis in chronic cardiopulmonary diseases. The usefulness of HRR to predict exercise impairment and mortality in patients with pulmonary arterial hypertension (PAH), however, remains largely unexplored.

METHODS

Seventy-two patients with PAH of varied etiology (New York Heart Association classes I-IV) and 21 age- and gender-matched controls underwent a maximal incremental cardiopulmonary exercise test (CPET), with heart rate being recorded up to the fifth minute of recovery.

RESULTS

Heart rate recovery was consistently lower in the patients compared with the controls (P < .05). The best cutoff for HRR in 1 minute (HRR(1 min)) to discriminate the patients from the controls was 18 beats. Compared with patients with HRR(1 min) ≤ 18 (n = 40), those with HRR(1 min) >18 (n = 32) had better New York Heart Association scores, resting hemodynamics and 6-minute walking distance. In fact, HRR(1 min) >18 was associated with a range of maximal and submaximal CPET variables indicative of less severe exercise impairment (P < .05). The single independent predictor of HRR(1 min) ≤ 18 was the 6-minute walking distance (odds ratio [95% CI] 0.99 [0.98-1.00], P < .05). On a multiple regression analysis that considered only CPET-independent variables, HRR(1 min) ≤ 18 was the single predictor of mortality (hazard ratio [95% CI] 1.19 [1.03-1.37], P < .05).

CONCLUSIONS

Preserved HRR(1 min) (>18 beats) is associated with less impaired responses to incremental exercise in patients with PAH. Conversely, a delayed HRR(1 min) response has negative prognostic implications, a finding likely to be clinically useful when more sophisticated (and costlier) analyses provided by a full CPET are not available.