Consumo máximo de oxígeno durante la prueba de marcha de 6 minutos en la enfermedad pulmonar intersticial difusa y en la hipertensión pulmonar

Introduction

The six-minute walk test (6MWT) is widely used in evaluating diffuse interstitial lung disease (ILD) and pulmonary hypertension (PH). However, their physiological determining factors have not been well defined.

Objective

To evaluate the physiological changes that occur in ILD and PH during the 6MWT, and compare them with the cardiopulmonary exercise test (CPET).

Material and methods

Thirteen patients with ILD and 14 with PH were studied using the 6MWT and CPET on an ergometer cycle. The respiratory variables were recorded by means of telemetry during the 6MWT.

Results

Oxygen consumption (VO₂), respiratory and heart rate reached a plateau from minute 3 of the 6MWT in both diseases. The VO₂ did not differ from the peak value in the CPET (14±2 and 15±2 ml/kg/min, respectively, in ILD; 16±6 and 16±6 ml/kg/min, in PH). The arterial oxygen saturation decreased in both diseases, although it was more marked in ILD (−12±5%, p<0,01). The ventilatory equivalent for CO₂ (V_E/VCO₂) in PH during the 6MWT was strongly associated with functional class (FC) (85±14 in FC III-IV, 44±6 in FC I-II; p<0,001).

Conclusions

The 6MWT in ILD and PH behaves like a maximal effort test, with similar VO₂ to the CPET, demonstrating a limit in oxygen transport capacity. Monitoring using telemetry during the 6MWT may be useful for the clinical evaluation of patients with ILD or PH.     

Prueba de marcha de 6 min y ejercicio máximo en cicloergómetro en la enfermedad pulmonar obstructiva crónica, ¿son sus demandas fisiológicas equivalentes?

Background and objectives

The physiological load imposed by the six minute walk test (SMWT) in chronic obstructive pulmonary disease (COPD) patients come from small studies where the influence of disease severity has not been assessed. The aim of the present study was to compare the SMWT with an incremental cardiopulmonary exercise test (CPET) in patients classified by disease severity according to FEV₁ (cutoff 50% predicted).

Patients and methods

Eighty-one COPD patients (53 with FEV₁ ≥50%) performed both tests on two consecutive days. Oxygen consumption (O₂), carbon dioxide production (CO₂), minute ventilation (_E), heart rate (HR) and pulse oximetry (SpO₂) were measured during SMWT and CPET using portable equipment. Dyspnea and leg fatigue were measured with the Borg scale.

Results

In both groups, walking speed was constant during the SMWT and O₂ showed a plateau after the 3rd minute. When comparing SMWT (6th min) and peak CPET, patients with FEV₁ ≥50% showed a greater O₂, but lower values of CO₂,V_E, HR, dyspnea, leg fatigue, and SpO₂ during walking. In contrast, in those with FEV₁ <50% predicted values were similar. Distance walked during the SMWT strongly correlated with O₂ at peak CPET (r=0.78; P=0.0001).

Conclusion

The SMWT is a constant load exercise in COPD patients, regardless of disease severity. It imposes high metabolic, ventilatory and cardiovascular requirements, which were closer to those of CPET in severe COPD. These findings may explain the close correlation between distance walked and peak CPET O₂.     

Cardiopulmonary exercise testing is more accurate than ECG-stress testing in diagnosing myocardial ischemia in subjects with chest pain

Background

Cardiopulmonary exercise stress testing (CPET) is used to grade the severity of heart failure and to assess its prognosis. However it is unknown whether CPET may improve diagnostic accuracy of standard ECG stress testing to identify or exclude obstructive coronary artery disease (O-CAD) in patients with chest pain.

Methods

We prospectively studied 1265 consecutive subjects (55 ± 8 years, 156 women) who were evaluated with ECG stress testing (ET) for chest pain. No one had a documented O-CAD. All patients performed an incremental CPET with ECG recordings on an electronically braked cycle ergometer.

Results

Of 1265 patients, 73 had a positive CPET and 1192 had a negative CPET. Seventy-three patients with a positive CPET and 71 patients with a negative CPET agreed to undergo nuclear SPECT imaging and coronary angiography. Follow-up lasted 48 ± 7 months. As compared with ET, sensitivity, specificity, PPV and NPV were all improved significantly (ET: 48%, 55%, 33%, 95%; CPET: 88%, 98%, 73%, 99%, respectively, P < 0.001). Patients with both peak VO₂ > 91% of predicted VO₂ max and absence of VO₂-related signs of myocardial ischemia had no evidence of O-CAD in 100% of cases. Cardiac events occurred in 32 patients with a positive CPET and 8 patients with a negative CPET (log rank 18.2, P < 0.0001).

Conclusions

In patients with chest pain, CPET showed a better diagnostic and predictive accuracy than traditional ET to detect/exclude myocardial ischemia. Its use should be encouraged among physicians as a first line diagnostic tool in clinical practice.     

Usefulness of cardiopulmonary exercise testing to predict the development of arterial hypertension in adult patients with repaired isolated coarctation of the aorta

Background

Patients who underwent surgery for aortic coarctation (COA) have an increased risk of arterial hypertension. We aimed at evaluating (1) differences between hypertensive and non-hypertensive patients and (2) the value of cardiopulmonary exercise testing (CPET) to predict the development or progression of hypertension.

Methods

Between 1999 and 2010, CPET was performed in 223 COA-patients of whom 122 had resting blood pressures of < 140/90 mm Hg without medication, and 101 were considered hypertensive. Comparative statistics were performed. Cox regression analysis was used to assess the relation between demographic, clinical and exercise variables and the development/progression of hypertension.

Results

At baseline, hypertensive patients were older (p = 0.007), were more often male (p = 0.004) and had repair at later age (p = 0.008) when compared to normotensive patients. After 3.6 ± 1.2 years, 29/120 (25%) normotensive patients developed hypertension. In normotensives, VE/VCO₂-slope (p = 0.0016) and peak systolic blood pressure (SBP; p = 0.049) were significantly related to the development of hypertension during follow-up. Cut-off points related to higher risk for hypertension, based on best sensitivity and specificity, were defined as VE/VCO₂-slope ≥ 27 and peak SBP ≥ 220 mm Hg. In the hypertensive group, antihypertensive medication was started/extended in 48/101 (48%) patients. Only age was associated with the need to start/extend antihypertensive therapy in this group (p = 0.042).

Conclusions

Higher VE/VCO₂-slope and higher peak SBP are risk factors for the development of hypertension in adults with COA. Cardiopulmonary exercise testing may guide clinical decision making regarding close blood pressure control and preventive lifestyle recommendations.     

COPD in chronic heart failure: Less common than previously thought?

Background

Using a fixed ratio of forced expiratory volume in 1 s to forced vital capacity (FEV₁/FVC) < 0.70 instead of the lower limit of normal (LLN) to define chronic obstructive pulmonary disease (COPD) may lead to overdiagnosis of COPD in elderly patients with heart failure (HF) and consequently unnecessary treatment with possible adverse health effects.

Objective

The aim of this study was to determine COPD prevalence in patients with chronic HF according to two definitions of airflow obstruction.

Methods

Spirometry was performed in 187 outpatients with stable chronic HF without pulmonary congestion who had a left ventricular ejection fraction <40% (mean age 69 ± 10 years, 78% men). COPD diagnosis was confirmed 3 months after standard treatment with tiotropium in newly diagnosed COPD patients.

Results

COPD prevalence varied substantially between 19.8% (LLN-COPD) and 32.1% (GOLD-COPD). Twenty-three of 60 patients (38.3%) with GOLD-COPD were potentially misclassified as having COPD (FEV₁/FVC < 0.7 but > LLN). In contrast to patients with LLN-COPD, potentially misclassified patients did not differ significantly from those without COPD regarding respiratory symptoms and risk factors for COPD.

Conclusions

One fifth, rather than one third, of the patients with chronic HF had concomitant COPD using the LLN instead of the fixed ratio. LLN may identify clinically more important COPD than a fixed ratio of 0.7.     

Differences in pulmonary function and exercise capacity in patients with idiopathic dilated cardiomyopathy and idiopathic pulmonary arterial hypertension

Objectives

We observed the pulmonary function and exercise capacity of idiopathic dilated cardiomyopathy (IDCM) and idiopathic pulmonary arterial hypertension (IPAH) patients using cardiopulmonary exercise testing (CPX). We evaluated and compared the two groups.

Background

Pulmonary abnormalities and decreased exercise capacity are common in IDCM and IPAH. Little is known about the differences in these two syndromes.

Methods

Sixty-three patients were involved the study, 23 with IDCM and 40 with IPAH. All patients underwent pulmonary function testing at rest and CPX.

Results

Patients with IPAH had a higher peak respiratory frequency (32.40 ± 7.88 vs 29.60 ± 6.50 b/min), peak dead space volume/tidal volume (29.33 ± 4.55 vs 26.30  ± 3.31%), peak end-tidal partial pressure of O₂ (125.18 ± 5.88 vs 115.17 ± 6.06 mm Hg), peak minute ventilation/CO₂ production (50.14 ± 13.26 vs 33.50 ± 6.80 L/min/L/min), and a lower peak oxygen uptake (1262.70 ± 333.34 vs 742.76 ± 194.72 ml/min), peak minute ventilation (38.20 ± 13.07 vs 45.33 ± 12.31 L), peak oxygen uptake/heart rate (5.11 ± 1.47 vs 9.43 ± 2.79 ml/b) and peak end-tidal partial pressure of CO₂ (23.73 ± 5.39 vs 35.30 ± 5.45 mm Hg) during exercise.

Conclusions

Compared to IDCM, patients with IPAH had worse pulmonary function and exercise capacity resulting from severe ventilation/perfusion mismatching and gas exchange abnormalities.     

Subgroup analysis of symptoms and their effect on functioning,exercise capacity,and physical activity in patients with severe chronic obstructive pulmonary disease

Background

Little is known about symptom clusters and their effect on outcomes in people with chronic obstructive pulmonary disease (COPD).

Purposes

To determine whether subgroups of patients with COPD could be identified by symptom ratings, whether they differed on selected demographic and clinical characteristics, and whether they differed on functioning, exercise capacity, and physical activity.

Method

Subjects with severe COPD (n = 596) were drawn from the National Emphysema Treatment Trial dataset. Data were drawn from questionnaires and clinical measures.

Results

Two subgroup clusters emerged from four symptoms. Mean age and the proportion of participants with higher education, higher income levels, and using oxygen at rest were significantly different between subgroups. Participants with high levels of symptoms had lower functioning and decreased exercise capacity. Symptom cluster subgroups were significantly associated with social functioning.

Conclusion

These findings suggest that screening for high levels of symptoms may be important in patients with severe COPD.     

Hiking in Suicidal Patients: Neutral Effects on Markers of Suicidality

Background

Regular physical activity promotes physical and mental health. Psychiatric patients are prone to a sedentary lifestyle, and accumulating evidence has identified physical activity as a supplemental treatment option.

Methods

This prospective, randomized, crossover study evaluated the effects of hiking in high-risk suicidal patients (n = 20) who performed 9 weeks of hiking (2-3 hikes/week, 2-2.5 hours each) and a 9-week control period.

Results

All patients participated in the required 2 hikes per week and thus showed a compliance of 100%. Regular hiking led to significant improvement in maximal exercise capacity (hiking period Δ: +18.82 ± 0.99 watt, P < .001; control period: P = .134) and in aerobic capability at 70% of the individual heart rate reserve (hiking period Δ: +8.47 ± 2.22 watt; P = .010; control period: P = .183). Cytokines, associated previously with suicidality (tumor necrosis factor-α, interleukin-6, S100), remained essentially unchanged.

Conclusions

Hiking is an effective and safe form of exercise training even in high-risk suicidal patients. It leads to a significant improvement in maximal exercise capacity and aerobic capability without concomitant deterioration of markers of suicidality. Offering this popular mode of exercise to these patients might help them to adopt a physically more active lifestyle.     

Randomized Trial of Nordic Walking in Patients With Moderate to Severe Heart Failure

Background

Patients with heart failure are a growing population within cardiac rehabilitation. The purpose of this study was to compare, through a single-centre, parallel-group, randomized controlled trial, the effects of Nordic walking and standard cardiac rehabilitation care on functional capacity and other outcomes in patients with moderate to severe heart failure.

Methods

Between 2008 and 2009, 54 patients (aged 62.4 ± 11.4 years) with heart failure (mean ejection fraction = 26.9% ± 5.0%) were randomly assigned to standard cardiac rehabilitation care (n = 27) or Nordic walking (n = 27); both groups performed 200 to 400 minutes of exercise per week for 12 weeks. The primary outcome, measured after 12 weeks, was functional capacity assessed by a 6-minute walk test (6MWT).

Results

Compared with standard care, Nordic walking led to higher functional capacity (Δ 125.6 ± 59.4 m vs Δ 57.0 ± 71.3 m travelled during 6MWT; P = 0.001), greater self-reported physical activity (Δ 158.5 ± 118.5 minutes vs Δ 155.5 ± 125.6 minutes; P = 0.049), increased right grip strength (Δ 2.3 ± 3.5 kg vs Δ 0.3 ± 3.1 kg; P = 0.026), and fewer depressive symptoms (Hospital Anxiety and Depression Scale score = Δ −1.7 ± 2.4 vs Δ −0.8 ± 3.1; P = 0.014). No significant differences were found for peak aerobic capacity, left-hand grip strength, body weight, waist circumference, or symptoms of anxiety.

Conclusions

Nordic walking was superior to standard cardiac rehabilitation care in improving functional capacity and other important outcomes in patients with heart failure. This exercise modality is a promising alternative for this population.     

Exercise Capacity and Ventilatory Response During Exercise in COPD Patients With and Without β Blockade

Background

Although β blockade (BB) in patients with chronic obstructive pulmonary disease (COPD) does not show signs of worsening pulmonary function or respiratory symptoms, the effects on cardiopulmonary exercise testing (CPET) remain unclear. The aim of this study was to determine whether BB affects exercise capacity, gas exchange, and hemodynamic responses in patients with COPD.

Methods

Twenty-four COPD subjects on BB were matched to 24 COPD subjects without BB according to age, gender, body mass index, and severity of COPD. All subjects underwent resting pulmonary function and symptom-limited CPET.

Results

Comparing COPD patients with and without BB revealed that percent peak oxygen consumption and VE/VCO₂ nadir were not significantly different (45 ± 16 vs. 51 ± 23 %, p = 0.30, and 35.1 ± 8.5 vs. 36.2 ± 11.6 %, p = 0.69). Systolic blood pressure and heart rate at peak exercise were significantly decreased in COPD patients with BB (168 ± 16 vs. 185 ± 20 mmHg, and 109 ± 16 vs. 122 ± 14 bpm, respectively, p < 0.05).

Conclusion

Exercise capacity and gas exchange remain unaffected in patients with COPD in the presence of BB, although heart rate and blood pressure are lower. These findings imply that BB does not adversely affect functional capacity in patients with COPD.     

A neural network approach to predicting outcomes in heart failure using cardiopulmonary exercise testing

Objectives

To determine the utility of an artificial neural network (ANN) in predicting cardiovascular (CV) death in patients with heart failure (HF).

Background

ANNs use weighted inputs in multiple layers of mathematical connections in order to predict outcomes from multiple risk markers. This approach has not been applied in the context of cardiopulmonary exercise testing (CPX) to predict risk in patients with HF.

Methods

2635 patients with HF underwent CPX and were followed for a mean of 29 ± 30 months. The sample was divided randomly into ANN training and testing sets to predict CV mortality. Peak VO₂, VE/VCO₂ slope, heart rate recovery, oxygen uptake efficiency slope, and end-tidal CO₂ pressure were included in the model. The predictive accuracy of the ANN was compared to logistic regression (LR) and a Cox proportional hazards (PH) score. A multi-layer feed-forward ANN was used and was tested with a single hidden layer containing a varying number of hidden neurons.

Results

There were 291 CV deaths during the follow-up. An abnormal VE/VCO₂ slope was the strongest predictor of CV mortality using conventional PH analysis (hazard ratio 3.04; 95% CI 2.2–4.2, p < 0.001). After training, the ANN was more accurate in predicting CV mortality compared to LR and PH; ROC areas for the ANN, LR, and PH models were 0.72, 0.70, and 0.69, respectively. Age and BMI-adjusted odds ratios were 4.2, 2.6, and 2.9, for ANN, LR, and PH, respectively.

Conclusion

An ANN model slightly improves upon conventional methods for estimating CV mortality risk using established CPX responses.     

Pulmonary rehabilitation improves heart rate variability at peak exercise,exercise capacity and health-related quality of life in chronic obstructive pulmonary disease

Objective

Patients with chronic obstructive pulmonary disease (COPD) appear to have impaired cardiac autonomic modulation with depressed heart rate variability (HRV). Pulmonary rehabilitation (PR) is recommended as an integral part of the management. However, the effect of PR on HRV at peak exercise remains unclear.

Methods

Sixty-four patients with COPD participated in a 12-week, 2 sessions-per-week, hospital-based PR program. Baseline and post-PR status were evaluated by spirometry, HRV, health-related quality of life (HRQL, St. George's Respiratory Questionnaire, SGRQ), cardiopulmonary exercise test, respiratory muscle strength, and dyspnea Borg's scale.

Results

After PR, there were significant improvements in the time and frequency domains of HRV with increased standard deviation of the normal R–R intervals, difference between adjacent normal R–R intervals within a given time minus one, high-frequency and decreased low-frequency, as well as concurrent improvements in HRQL, exercise capacity, dyspnea score, and respiratory muscle strength (all p < 0.05).

Conclusions

PR results in significant improvements in autonomic function, with concurrent improvements in HRQL and exercise capacity.     

Quantitative Assessment of Myocardial Perfusion in the Detection of Significant Coronary Artery Disease : Cutoff Values and Diagnostic Accuracy of Quantitative [O]H2O PET Imaging

Background

Recent studies have demonstrated improved diagnostic accuracy for detecting coronary artery disease (CAD) when myocardial blood flow (MBF) is quantified in absolute terms, but there are no uniformly accepted cutoff values for hemodynamically significant CAD.

Objectives

The goal of this study was to determine cutoff values for absolute MBF and to evaluate the diagnostic accuracy of quantitative [¹⁵O]H₂O positron emission tomography (PET).

Methods

A total of 330 patients underwent both quantitative [¹⁵O]H₂O PET imaging and invasive coronary angiography in conjunction with fractional flow reserve measurements. A stenosis >90% and/or fractional flow reserve ≤0.80 was considered obstructive; a stenosis <30% and/or fractional flow reserve >0.80 was nonobstructive.

Results

Hemodynamically significant CAD was diagnosed in 116 (41%) of 281 patients who fulfilled study criteria for CAD. Resting perfusion was 1.00 ± 0.25 and 0.92 ± 0.23 ml/min/g in regions supplied by nonstenotic and significantly stenosed vessels, respectively (p < 0.001). During stress, perfusion increased to 3.26 ± 1.04 ml/min/g and 1.73 ± 0.67 ml/min/g, respectively (p < 0.001). The optimal cutoff values were 2.3 and 2.5 for hyperemic MBF and myocardial flow reserve, respectively. For MBF, these cutoff values showed a sensitivity, specificity, and accuracy for detecting significant CAD of 89%, 84%, and 86%, respectively, at a per-patient level and 87%, 85%, and 85% at a per-vessel level. The corresponding myocardial flow reserve values were 86%, 72%, and 78% (per patient) and 80%, 82%, and 81% (per vessel). Age and sex significantly affected diagnostic accuracy of quantitative PET.

Conclusions

Quantitative MBF measurements with the use of [¹⁵O]H₂O PET provided high diagnostic performance, but both sex and age should be taken into account.     

High hexacosanoic acid levels are associated with coronary artery disease

Aims

Levels of saturated very long chain fatty acids (VLCFAs) are associated with coronary risk factors, including metabolic syndrome (MS), atherogenic lipoproteins, and systemic inflammation. However, the relationship between circulating levels of saturated VLCFA and coronary artery disease (CAD) remains unclear.

Method

We enrolled 100 consecutive CAD patients and 40 age-, gender-, and body mass index (BMI)-matched healthy control subjects. The levels of hexacosanoic acid (C26:0), a VLCFA, in whole blood were measured by gas–liquid chromatography mass spectrometry.

Results

C26:0 levels were significantly higher in the CAD group than in the control group (2.42 ± 0.32 vs. 2.27 ± 0.24 μg/ml, P = 0.01) and positively correlated with BMI (r = 0.23, P = 0.008), triglyceride levels (r = 0.22, P = 0.01), and hypertension (P = 0.01). CAD patients with MS showed the highest C26:0 levels adjusted by hematocrit. Furthermore, adjusted C26:0 levels in CAD patients without MS were higher than those in controls (P = 0.02), suggesting that C26:0 levels increased with the presence of CAD independent of MS. Our multivariate analysis revealed that high C26:0 levels in whole blood is an independent marker for CAD even after adjustment for age, gender, BMI, lipid profiles, fasting plasma glucose, and blood pressure.

Conclusion

High C26:0 levels in whole blood may be an independent marker for identifying the risks of CAD.     

Distribución de fenotipos clínicos en pacientes con enfermedad pulmonar obstructiva crónica por humo de biomasa y por tabaco

Introduction

Exposure to biomass smoke is a risk factor for chronic obstructive pulmonary disease (COPD). It is unknown whether COPD caused by biomass smoke has different characteristics to COPD caused by tobacco smoke.

Objective

To determine clinical differences between these two types of the disease.

Methods

Retrospective observational study of 499 patients with a diagnosis of COPD due to biomass or tobacco smoke. The clinical variables of both groups were compared.

Results

There were 122 subjects (24.4%) in the biomass smoke group and 377 (75.5%) in the tobacco smoke group. In the tobacco group, the percentage of males was higher (91.2% vs 41.8%, P < .0001) and the age was lower (70.6 vs 76.2 years, P < .0001). Body mass index and FEV₁% values were higher in the biomass group (29.4 ± 5.7 vs 28.0 ± 5.1, P = .01, and 55.6 ± 15.6 vs 47.1 ± 17.1, P < .0001, respectively). The mixed COPD-asthma phenotype was more common in the biomass group (21.3% vs 5%, P < .0001), although this difference disappeared when corrected for gender. The emphysema phenotype was more common in the tobacco group (45.9% vs 31.9%, P = .009). The prevalence of the chronic bronchitis and exacerbator phenotypes, the comorbidity burden and the rate of hospital admissions were the same in both groups.

Conclusion

Differences were observed between COPD caused by biomass and COPD caused by tobacco smoke, although these may be attributed in part to uneven gender distribution between the groups.     

Orosomucoid secretion levels by epicardial adipose tissue as possible indicator of endothelial dysfunction in diabetes mellitus or inflammation in coronary artery disease

Objective

Type 2 diabetes mellitus (T2DM) is associated with fat and autonomic system dysfunction. Epicardial adipose tissue (EAT) plays an endocrine role over the heart. Since orosomucoid (ORM) has local actions around the coronaries, our aim was to assess the relationship between its secretion profile by EAT and its catecholaminergic regulation in patients with T2DM and coronary artery disease (CAD).

Methods

We obtained EAT, subcutaneous adipose tissue (SAT) and plasma from 55 patients undergoing cardiac surgery. Fat explants were stimulated with isoproterenol (ISO) 1 μM for 6 h. After, the fat explants released-ORM and plasma levels were analyzed by ELISA. mRNA or protein expression was analyzed by real time PCR or western blot, respectively. The effects of ORM on endothelial cells were analyzed by impedance and wound healing assays.

Results

We observed that EAT-released ORM levels were higher than SAT (328 ± 185 vs 58 ± 45 ng/mL; p < 0.001). Interestingly, EAT secretion was lower in patients with than those without T2DM (260 ± 141 vs 370 ± 194 ng/mL; p < 0.05) and this difference was enhanced after ISO stimulation (p < 0.01). However, plasma levels (412 ± 119 vs 594 ± 207 μg/mL) and EAT-released ORM levels were higher in patients with than those without CAD (384 ± 195 vs 279 ± 159 ng/mL; p < 0.05). ISO stimulation, also reduced the EAT released-ORM levels in patients with CAD. On human endothelial cells, ORM induced an increase of healing and proliferation in a dose-dependent manner.

Conclusion

EAT-released ORM levels in patients with T2DM or CAD and its regulation by catecholamines might be the mirror of local endothelium dysfunction or inflammatory process in different cardiovascular disorders.     

Oxygen uptake efficiency slope, a new submaximal parameter in evaluating exercise capacity in chronic heart failure patients

Background

The oxygen uptake efficiency slope (OUES) is a new submaximal parameter which objectively predicts the maximal exercise capacity in children and healthy subjects. However, the usefulness of OUES in adult patients with and without advanced heart failure remains undetermined. The present study investigates the stability and the usefulness of OUES in adult cardiac patients with and without heart failure.

Methods

Forty-five patients with advanced heart failure (group A) and 35 patients with ischemic heart disease but normal left ventricular ejection fraction (group B) performed a maximal exercise test. PeakVO₂ and percentage of predicted peakVO₂ were markers of maximal exercise capacity, whereas OUES, ventilatory anaerobic threshold (VAT), and slope VE/VCO₂ were calculated as parameters of submaximal exercise.

Results

Group A patients had lower peakVO₂ (P < .001), lower percentage of predicted peakVO₂ (P = .001), lower VAT (P < .05), steeper slope VE/VCO₂ (P < .001), and lower OUES (P < .02). Within group A, significant differences were found for VAT, slope VE/VCO₂, and OUES (all P < .01) between patients with peakVO₂ above and below 14 mL O₂/kg/min. Of all the submaximal parameters, VAT correlated best with peakVO₂ (r =.814, P < .01) followed by OUES/kg (r = .781, P < .01), and slope VE/VCO₂ (r = −.492, P < .001). However, VAT could not be determined in 18 (23%) patients.

Conclusions

OUES remains stable over the entire exercise duration and is significantly correlated with peakVO₂ in adult cardiac patients with and without impaired LVEF. Therefore, OUES could be helpful to assess exercise performance in advanced heart failure patients unable to perform a maximal exercise test. Further studies are needed to confirm our hypothesis.     

Association of Lp-PLA2 with digital reactive hyperemia,coronary flow reserve,carotid atherosclerosis and arterial stiffness in coronary artery disease

Background

Lipoprotein-associated Phospholipase A2 (Lp-PLA2), has a powerful inflammatory and atherogenic action in the vascular wall and is an independent marker of poor prognosis in coronary artery disease (CAD). We investigate the association of Lp-PLA2 with markers of vascular dysfunction and atherosclerosis with proven prognostic value in CAD.

Methods

In 111 patients with angiographically documented chronic CAD, we measured 1) carotid intima-media thickness (CIMT), 2) reactive hyperemia using fingertip peripheral arterial tonometry (RH-PAT), 3) coronary flow reserve (CFR), by Doppler echocardiography 4) pulse wave velocity (PWV) and 5) blood levels of Lp-PLA2.

Results

Patients with Lp-PLA2 concentration >234.5 ng/ml (50th percentile) had higher CIMT (1.44 ± 0.07 vs. 1.06 ± 0.06 mm), PWV (11.0 ± 2.36 vs. 9.7 ± 2.38 m/s) and lower RH-PAT(1.24 ± 0.25 vs. 1.51 ± 0.53) and CFR (2.39 ± 0.75 vs. 2.9 ± 0.86) compared to those with lower Lp-PLA (p < 0.05 for all comparisons). Lp-PLA2 was positively associated with CIMT (regression coefficient b: 0.30 per unit of Lp-PLA2, p = 0.02), PWV (b:0.201, p = 0.04) and inversely with RHI-PAT (b: −0.371, p < 0.001) and CFR (b:−0.32, p = 0.002). In multivariate analysis, Lp-PLA2 was an independent determinant of RHI-PAT, CFR, CIMT and PWV in a model including age, sex, smoking, diabetes, dyslipidemia and hypertension (p < 0.05 for all vascular markers). Lp-PLA2, RHI-PAT and CFR were independent predictors of cardiac events during a 3-year follow-up.

Conclusions

Elevated Lp-PLA2 concentration is related with endothelial dysfunction, carotid atherosclerosis, impaired coronary flow reserve and increased arterial stiffness and adverse outcome in CAD patients. These findings suggest that the prognostic role of Lp-PLA2 in chronic CAD may be explained by a generalized detrimental effect of this lipase on endothelial function and arterial wall properties.     

Predictors of exercise capacity and the impact of angiographic coronary artery disease in heart transplant recipients

Background

Maximal exercise capacity is limited in patients after heart transplantation. The extent to which transplant coronary artery disease contributes to exercise intolerance in these patients has not been well defined.

Methods

This prospective study examined exercise capacity among 174 heart transplant recipients who underwent 358 exercise tests 0.3 to 13 years after surgery. Data were collected as part of routine posttransplantation treatment that each year consist of clinical and hemodynamic measurements (including ejection fraction, cardiac index, pulmonary capillary wedge pressure, and the presence of coronary artery disease) and cardiopulmonary exercise test (including measures of peak Vo₂). The mean follow-up was 3.5 ± 0.2 years after transplantation. Serial exercise test data were available in 102 patients

Results

Peak Vo₂ was 19.4 ± 0.4 mL/kg per minute, representing 70% ± 1.3% of the age-predicted value. Exercise capacity increased significantly after transplantation and then remained stable throughout long-term follow-up. Only age, maximal systolic blood pressure, pulmonary vascular resistance, and body mass index were independent determinants of exercise capacity (R² = 0.51), whereas specific transplant factors such as denervation, hemodynamic variables, donor characteristics, immunosuppressive drugs, biochemical parameters, and transplant coronary artery disease (TxCAD) did not contribute to the explanation of reduced exercise capacity. Although TxCAD was not related to exercise capacity in the multivariate analysis, exercise capacity declined by 17.1% (P < .05) among those in whom CAD developed during follow-up.

Conclusions

Exercise capacity is reduced among heart transplant recipients, and age is the strongest determinant of aerobic performance. Specific transplant-related factors, including TxCAD, do not contribute significantly to the explanation of exercise capacity. However, the occurrence of TxCAD may contribute to reduced exercise capacity during follow-up, since peak Vo₂ appears to decline only among those who have TxCAD.     

Intensive Lifestyle Intervention Improves Cardiometabolic and Exercise Parameters in Metabolically Healthy Obese and Metabolically Unhealthy Obese Individuals

Background

The effects of an intensive lifestyle intervention including Mediterranean diet nutritional counselling and high-intensity interval training (HIIT) on body composition, cardiometabolic, and exercise parameters were studied in metabolically unhealthy obese (NMHO) and metabolically healthy but obese (MHO) subjects.

Methods

Fifty-five MHO (51 ± 8 years; waist circumference, 109 ± 13 cm) and 79 NMHO subjects (54 ± 9 years; waist circumference, 112 ± 13 cm) participated in an intensive lifestyle modification program based on Mediterranean diet nutritional counselling and HIIT 2-3 times per week. Body composition, cardiometabolic, and exercise parameters were measured at baseline and after 9 months.

Results

Initially, MHO patients had a lower blood pressure (BP), fasting glycemia, triglycerides, and a higher high-density lipoprotein cholesterol and peak oxygen uptake (VO₂ peak) (P < 0.05) vs NMHO patients. Body mass (P < 0.05), waist circumference (P < 0.0001), total and trunk fat mass (P < 0.001), systolic and diastolic BP (P < 0.001), fasting glucose (P < 0.0001), insulin sensitivity (P < 0.05), VO₂ peak and muscle endurance (P < 0.0001) were similarly improved in both groups after the program. Prevalence of NMHO was reduced by 17.91% (P < 0.01) after the program. Similar improvements in body composition, BP, and exercise parameters were found for MHO and NMHO men and women (P < 0.05). In all patients, improvement of VO₂ peak was negatively correlated with improvements in body composition, systolic blood pressure, and resting heart rate (HR) (R = −0.61 to −0.24; P < 0.05).

Conclusions

A long-term intensive lifestyle program including Mediterranean diet nutritional counselling and HIIT is an appropriate intervention in MHO and NMHO subjects with similar potential clinical health benefits including an improved body composition, BP, fasting glycemia, insulin sensitivity, VO₂ peak, and muscle endurance.