Lower Anaerobic Threshold Research Articles

Determinants of Anaerobic Threshold at Each Stage of Renal Dysfunction in Patients With Heart Disease

Patients with heart disease have a low anaerobic threshold (AT), and the determinants of AT may differ, depending on the severity of renal dysfunction. This study aimed to verify the determinants of AT for each stage of renal function in patients with heart disease. We consecutively enrolled 250 patients with heart disease who underwent cardiopulmonary exercise testing in our institution. The patients were divided into 3 groups by their estimated glomerular filtration rate (eGFR): <45, 45 to 59, and ≥60ml/min/1.73m2. A multivariate linear regression analysis was performed to evaluate the independent determinants of AT for each group. In total, 201 patients were analyzed. AT decreased with the deterioration of renal function (eGFR <45, 10.9 ± 2.1 vs eGFR 45 to 59, 12.4 ± 2.5 vs eGFR ≥60, 14.0 ± 2.6ml/min/kg, p <0.001). In the eGFR <45 group, left ventricular ejection fraction and hemoglobin were significantly associated with AT (β=0.427, p=0.006 and β=0.488, p=0.002, respectively). In the eGFR 45 to 59 and ≥60 groups, ΔPETO2 (end-tidal oxygen partial pressure from rest to AT) showed a significant association with AT (β=0.576, p <0.001 and β=0.308, p=0.003, respectively). The determinants of AT depended on the stage of renal dysfunction in patients with heart disease. In conclusion, in the eGFR <45 group, the determinants of AT were left ventricular ejection fraction and hemoglobin, whereas in the eGFR 45 to 59 and eGFR ≥60 groups, the determinant of AT was ΔPETO2.

Cardiopulmonary Exercise Testing in Evaluation of Patients of Chronic Obstructive Pulmonary Disease

Objective assessment of severity in patients with chronic obstructive pulmonary disease (COPD) is mainly limited to pulmonary function testing performed at rest. But, accurate assessment of exercise capacity in patients with COPD may be possible with cardiopulmonary exercise testing (CPET). Forty-three patients with stable COPD were included and were divided into three groups based upon the spirometry data as per the Global Initiative for Obstructive Lung Disease (GOLD) guidelines as follows: Group A: mild COPD, Group B: moderately severe COPD and Group C: severe COPD. Symptom-limited CPET was performed using treadmill on incremental continuous ramp protocol in all of them. Five patients (11.6%) had mild COPD; 16 (37.2%) had moderately severe COPD and the remaining 22 (51.6%) patients had severe COPD. Anaerobic threshold was attained in all the 43 patients. The dominant symptom at peak exercise were dyspnoea (n = 19) and both dyspnoea and leg fatigue (n = 7). The other causes of exercise limitation included dyspnoea with significant oxygen desaturation (n = 6); and dyspnoea with severe oxygen desaturation (n = 2). Six patients complained only of leg fatigue at peak exercise. A significant correlation between forced expiratory volume in the first second (FEV1) percent predicted and the predicted maximum oxygen uptake (VO2 max % predicted) was observed in all the three groups (r = 0.39, p = 0.011) but with marked variability of peak VO2 for a given degree of airflow obstruction. Twenty-three (53.5%) patients with low anaerobic threshold (< 30%) were identified as potential group likely to benefit from exercise training for pulmonary rehabilitation. Cardiopulmonary exercise testing is useful to determine the causes of exercise limitation and to assess the maximal exercise capacity of patients with COPD.

P-OGC74 Effect of pre-operative anaemia on short-term outcomes following oesophagectomy: a 10-year retrospective cohort study

Abstract Background Pre-operative anaemia is associated with increased length of hospital stay, requirement for allogenic blood transfusion, post-operative complications and mortality. Oesophagectomy is a complex procedure associated with significant physiological insult, thus pre-operative patient optimisation is imperative to improve clinical outcomes. This study aimed to determine the impact of pre-operative anaemia on short-term outcomes following oesophagectomy for benign and malignant disease. Methods A retrospective cohort study of all oesophagectomies performed in a single tertiary referral centre between 1 January 2010 and 31 December 2019 was performed. Patients were identified from a prospectively collected database and individual patient electronic records were interrogated. Patients were dichotomised into two groups, based on the most recent pre-operative haemoglobin. Patients with pre-operative anaemia (haemoglobin &amp;lt;130mg/L in males and &amp;lt;120mg/L in females) were compared to those without pre-operative anaemia. Patients with missing data were excluded from the study. Patients were followed up for a median of 32 months (IQR 18-66). Results Of 352 patients eligible for inclusion, 173 (49.1%) patients were anaemic immediately pre-operatively. Patients with pre-operative anaemia were older (66 vs. 64 years, p = 0.031), with a lower anaerobic threshold (11.7 vs. 12.3ml/min/kg, p = 0.011), and were significantly more likely to have undergone neoadjuvant chemotherapy (91.3% vs. 78.8%, p &amp;lt; 0.001). Patient comorbidities and disease-related characteristics were similar between the two groups. Patients with pre-operative anaemia were significantly more likely to require post-operative blood transfusion (34.7% vs. 16.8%; p &amp;lt; 0.001). However, pre-operative anaemia was not associated with increased post-operative complications, intensive care admission, length of hospital stay, or 30- and 90-day mortality rates following oesophagectomy. Conclusions Patients with anaemia immediately prior to undergoing an oesophagectomy were significantly more likely to require post-operative blood transfusion. However, pre-operative anaemia was not associated with an increased rate of post-operative morbidity or mortality. In addition, pre-operative iron transfusion is becoming increasingly utilised to minimise the incidence of pre-operative anaemia: this was not analysed in this study.

Long-Term Outcomes After Fenestration Closure in High-Risk Fontan Candidates.

The study aimed to assess the long-term outcomes after fenestration closure in patients at risk for Fontan failure. Of 119 patients who underwent Fontan operation between 1995 and 2004, fenestration was not created in 89 patients (NF group) and created in 30 patients with hypoplastic left heart syndrome, heterotaxy syndrome, high pulmonary arterial pressure, high systemic ventricular end-diastolic pressure, low ventricular ejection fraction, or atrioventricular valve regurgitation. All fenestrations were closed spontaneously or by catheter/surgical interventions, excepting two patients, and therefore, they were excluded. In fenestration group, patients with pre-Fontan mean pulmonary arterial pressure ≥ 15mmHg or systemic atrioventricular valve regurgitation ≥ moderate were classified as high-risk Fontan candidates (F-HR group, n = 16), and the remaining patients were as standard-risk (F-SR group, n = 12). Protein-losing enteropathy-free survival rates did not differ among the three groups (p = 0.72). Serial follow-up catheter examinations after Fontan operation were completed in 69 patients in NF group and 11 patients in both F-SR and F-HR groups. Cardiac index and pulmonary vascular resistance significantly and similarly decreased over time in all groups, though the F-HR group showed lowest arterial oxygen saturation, lowest cardiac index, and highest pulmonary vascular resistance. The F-HR group also showed much veno-venous collaterals (p = 0.049), low peak oxygen consumption (p = 0.019), and low anaerobic threshold (p = 0.023) as compared to those in the F-SR group. In F-HR group, cyanosis remained after fenestration closure due to transformation from fenestration to veno-venous collaterals, which resulted in elevation of pulmonary vascular resistance, low cardiac index, and deterioration of exercise tolerance.

Posttraumatic Stress Disorder Is Associated With a Decrease in Anaerobic Threshold, Oxygen Pulse, and Maximal Oxygen Uptake

Posttraumatic stress disorder (PTSD) has been linked to respiratory symptoms and functional limitations, but the mechanisms leading to this association are poorly defined. What is the relationship between PTSD, lung function, and the cardiopulmonary response to exercise in combat veterans presenting with chronic respiratory symptoms? This study prospectively enrolled military service members with respiratory symptoms following deployment to southwest Asia. All participants underwent a comprehensive evaluation that included pulmonary function testing and cardiopulmonary exercise testing. Pulmonary function test variables and cardiopulmonary response to exercise were compared in subjects with and without PTSD by using multivariable linear regression to adjust for confounders. A total of 303 participants were included (PTSD, n= 70; non-PTSD, n= 233). Those with PTSD had a greater frequency of current respiratory symptoms. There were no differences in measures for airway disease or lung volumes, but patients with PTSD had a reduction in diffusing capacity that was eliminated following adjustment for differences in hemoglobin levels. Participants with PTSD had a lower anaerobic threshold (23.9 vs26.4 cc/kg per minute; P= .004), peak oxygen pulse (19.7 vs18.5 cc/beat; P= .03), and peak oxygen uptake (34.5 vs38.8 cc/kg per minute; P< .001). No significant difference was observed in gas exchange, respiratory reserve, or effort at peak exercise between participants with and without PTSD. A diagnosis of PTSD was associated with a reduced anaerobic threshold, oxygen pulse, and peak oxygen uptake. This objective reduction in cardiopulmonary work is independent of baseline lung function, was not associated with abnormalities in gas exchange or respiratory reserve, and may be related to deconditioning.

Exercise capacity in children with bronchopulmonary dysplasia at school age

ObjectiveTo assess the exercise capacity, exercise habits, and lung function of preterm born children with bronchopulmonary dysplasia (BPD) compared to term born controls at school age. MethodsCardiopulmonary exercise test (CPET) by cycle ergometer and pulmonary function test were performed in children with BPD (n = 42) and compared with a term born control group (n = 42). Daily activity, participation in sports and respiratory symptoms were assessed by questionnaire. ResultsChildren with BPD versus controls had significantly lower values for oxygen consumption (V̇O2 [mL/min] 1442 ± 417 vs. 1766 ± 541), minute ventilation (VE [L/min] 48 ± 14.92 vs. 60 ± 18.33), and workload (W [watt] 96.1 ± 16.7 vs. 110.6 ± 17.2) at peak exercise and a lower anaerobic threshold (VO2 AT [mL/min] 1183 ± 345 vs. 1382 ± 398). When corrected for weight, only for the workload (2.7 ± 0.5 vs. 3.1 ± 0.5, p = 0.0013) did significant differences persist. The forced expiratory volume in 1 s and forced expiratory flow between 25 and 75% of expired forced vital capacity were significantly reduced in the BPD group (p < 0.0001). Children with BPD have a higher risk of reporting difficulties in physical activity (OR 2.5) and of suffering from wheezing or shortness of breath while exercising (OR 2.5). ConclusionCompared to term born controls, children with BPD at school age show airflow obstruction, a lower workload in CPET, and more respiratory symptoms related to physical activity. The comparable oxygen consumption based on weight suggests a functionally normal alveolar compartment.

P138 IMPACT OF NEOADJUVANT FLOT CHEMOTHERAPY ON CARDIORESPIRATORY RESERVE OF PATIENTS WITH OESOPHAGOGASTRIC ADENOCARCINOMA

Abstract Introduction Neoadjuvant chemotherapy is known to have a deleterious effect on the cardiorespiratory reserve of patients with oesophagogastric cancer[1,2]. A low anaerobic threshold is associated with increased morbidity after major surgery[3] The effect that FLOT (5FU, leucovorin, oxaliplatin, docetakel) chemotherapy has upon cardiopulmonary reserve has not been reported. This work aims to quantify this effect. Methods Cardiopulmonary exercise testing (CPET) was completed in 18 consecutive patients with oesophagogastric cancer who received FLOT chemotherapy. CPET pre-chemotherapy and 4-5weeks post-chemotherapy measured the ventilatory anaerobic threshold (AT) and peak oxygen uptake (Vo2p). Ventilatory equivalents for CO2 (Ve/VCO2) and total ventilation (Ve) were reported. The group mean change in these objective measurements of cardiopulmonary reserve was compared before and after FLOT. Results Between October 2018 and January 2019 eighteen patients (median age 58.1 years, 16/18 male) were tested before and after FLOT. In 14 patients (78%) a decline in AT and VO2p was demonstrated. A mean decrease in AT of 2.1 mlkg-1min-1 (14.9 Vs 12.8 mlkg-1min-1, p=0.02) and VO2p of 2.3 mlkg-1min-1 (20.6 vs 18.3 mlkg-1min-1, p=0.01) was seen after FLOT. Ve/VCO2 and Ve were unchanged. Conclusion Patients receiving FLOT chemotherapy demonstrate a clinically significant decrease in cardiorespiratory reserve. This appears to be similar to that observed in patients who have previously received neoadjuvant ECX (MAGIC regimen) [1,2,4]. Further investigation into the clinical impact of this observation is required.

Characterising recovery from renal transplantation and live-related donation using cardiopulmonary exercise testing

Background An association between end-stage renal failure and exercise intolerance exists. Whether live kidney donation impacts on exercise tolerance is unknown. Here recovery post renal transplant and donation using cardiopulmonary exercise testing is investigated. Methods Renal donors (n = 28) and recipients (n = 24) undertook a cardiopulmonary exercise test, Duke activity score index and patient reported health score questionnaires pre-operatively and in the 7th and 14th week post-operatively. Anaerobic threshold, peak oxygen uptake and ventilatory equivalents were measured in relation to activity and reported health scores. Haemoglobin and renal function was recorded. Results Recipients showed impaired cardiopulmonary function compared to donors with lower anaerobic threshold (10.5 vs. 14.4 ml/kg/min) and peak oxygen uptake (18.5 vs 23.0 ml/kg/min). Post-operatively the anaerobic threshold of recipients improved and normalised by the 14th week, whereas that in donors fell by ∼20% by the 7th (mean 11.4 ml/kg/min), recovering by the 14th (mean 15.6 ml/kg/min). Reported health but not activity scores showed similar changes. Conclusions Recovery following renal transplantation and donation differ. Transplantation improves renal function resulting in an increase in anaerobic threshold and peak oxygen uptake which essentially normalise by the 14th week post-operatively. Donors suffer a 20% reduction in cardiopulmonary reserve post-operatively, which recovers by the 14th week, suggesting no associated chronic exercise intolerance. IMPLICATIONS FOR REHABILITATION Cardiopulmonary exercise testing is a real-time predictor of functional capacity and thus is used as a pre-operative tool to measure physiological fitness and predict outcomes. Renal failure is associated with exercise intolerance and transplantation is transformational in terms of quality of life, longevity and healthcare cost. Live – related renal donation is increasingly available but whether donation itself carries a long-term health burden has not been previously well established. This study suggests that renal donation is not associated with long-term cardiopulmonary compromise and patients who donate their kidneys recover their previous fitness within 14 weeks.

Cardiopulmonary fitness before and after neoadjuvant chemotherapy in patients with oesophagogastric cancer.

Neoadjuvant chemotherapy may have a detrimental impact on cardiorespiratory reserve. Determination of oxygen uptake at the anaerobic threshold by cardiopulmonary exercise testing (CPET) provides an objective measure of cardiorespiratory reserve. Anaerobic threshold can be used to predict perioperative risk. A low anaerobic threshold is associated with increased morbidity after oesophagogastrectomy. The aim of this study was to establish whether neoadjuvant chemotherapy has an adverse effect on fitness, and whether there is recovery of fitness before surgery for oesophageal and gastric adenocarcinoma. CPET was completed before, immediately after (week 0), and at 2 and 4 weeks after neoadjuvant chemotherapy. The ventilatory anaerobic threshold and peak oxygen uptake (Vo2 peak) were used as objective, reproducible measures of cardiorespiratory reserve. Anaerobic threshold and Vo2 peak were compared before and after neoadjuvant chemotherapy, and at the three time intervals. Some 31 patients were recruited. The mean anaerobic threshold was lower following neoadjuvant treatment: 15·3 ml per kg per min before chemotherapy versus 11·8, 12·1 and 12·6 ml per kg per min at week 0, 2 and 4 respectively (P < 0·010). Measurements were also significantly different at each time point (P < 0·010). The same pattern was noted for Vo2 peak between values before chemotherapy (21·7 ml per kg per min) and at weeks 0, 2 and 4 (17·5, 18·6 and 19·3 ml per kg per min respectively) (P < 0·010). The reduction in anaerobic threshold and Vo2 peak did not improve during the time between completion of neoadjuvant chemotherapy and surgery. There was a decrease in cardiorespiratory reserve immediately after neoadjuvant chemotherapy that was sustained up to the point of surgery at 4 weeks after chemotherapy.

Systematic Review and Meta-analysis of Objective Assessment of Physical Fitness in Patients Undergoing Colorectal Cancer Surgery.

Gas exchange-derived variables obtained from cardiopulmonary exercise testing allow objective assessment of functional capacity and hence physiological reserve to withstand the stressors of major surgery. Field walk tests provide an alternate means for objective assessment of functional capacity that may be cheaper and have greater acceptability, in particular, in elderly patients. This systematic review evaluated the predictive value of cardiopulmonary exercise testing and field walk tests in surgical outcomes after colorectal surgery. A systematic search was undertaken using Medline, PubMed, Embase, CINAHL, and PEDro. Adult patients who had cardiopulmonary exercise testing and/or field walk test before colorectal surgery were included. The primary outcomes measured were hospital length of stay and postoperative morbidity and mortality. A total of 7 studies with a cohort of 1418 patients who underwent colorectal surgery were identified for inclusion in a qualitative analysis. Both pooled oxygen consumption at anaerobic threshold (range, 10.1-11.1 mL·kg·min) and peak oxygen consumption (range, 16.7-18.6 mL·kg·min) were predictive of complications (OR for anaerobic threshold, 0.76; 95% CI, 0.66-0.85, p<0.0001; OR for peak oxygen consumption, 0.76; 95% CI, 0.67-0.85, p<0.0001). Patients had significant increased risk of developing postoperative complications if their anaerobic threshold was below this cut point (p<0.001). However, it was not predictive of anastomotic leak (p = 0.644). Shorter distance (<250 m) walked in incremental shuttle walk test, lower anaerobic threshold, and lower peak oxygen consumption were associated with prolonged hospital length of stay, which was closely related to the development of complications. Variables derived from cardiopulmonary exercise testing are predictive of postoperative complications and hospital length of stay. Currently, there are insufficient data to support the predictive role of the field walk test in colorectal surgery.

Features and clinical significance of cardiopulmonary exercise testing in elderly patients with coronary heart disease

Objective To examine the features and clinical significance of cardiopulmonary exercise testing(CPET)in elderly patients with coronary heart disease. Methods A retrospective study was conducted at the Fifth Affiliated Hospital of Zhengzhou University from September 2015 to August 2017.Fifty-nine elderly inpatients who had undergone coronary angiography and CPET were enrolled.The mean age was 61.5 years, and there were 48 males and 11 females.Based on the results of coronary angiography, patients were divided into a coronary heart disease(CAD)group(n=40)and a non-CAD group(n=19). Meanwhile, according to the degree of coronary stenosis assessed by angiography, the CAD group was further divided into two subgroups(Group A: coronary stenosis, 50%-70%, n=25; Group B: coronary stenosis, >70%, n=15). All results of CPET were compared between the groups. Results Patients in the CAD group were significantly associated with a lower anaerobic threshold(855.8±207.0)ml/min vs.(976.5±231.8)ml/min, a lower peak VO2(1 371.5±388.8)ml/min vs.(1652.8±435.5)ml/min, a lower percentage of peak VO2(18.3±4.7)ml·min-1·kg-1vs.(22.0±4.4)ml·min-1·kg-1, a lower peak O2-pulse(65.6±14.8)% vs.(85.5±14.9)% and a lower ΔVO2/ΔWR slope to expected value(8.0±1.1)ml·min-1·W-1vs.(9.1±1.5)ml·min-1·W-1, compared with those in the non-CAD group(all P ATand ΔVO2/ΔWRRatio to expected value were lower in Group B(7.5±1.3 vs.8.3±1.0, t=2.317, P=0.026), (6.2±1.9 vs.7.6±1.2, t=2.815, P=0.008)and(0.7±0.2vs.0.9±0.1, t=2.957, P=0.005). There was no difference in ΔVO2/ΔWR 0.05). Conclusions Exercise tolerance is lower in elderly CAD patients than those without CAD, and ΔVO2/ΔWR is decreased during the process of exercise, especially after the AT, which may be associated with low cardiac output due to left ventricular myocardial ischemia.This finding suggests that CPET can provide evidence of ischemia in patients with coronary heart disease and is valuable for the development of diagnostic and therapeutic strategies. Key words: Exercise test; Coronary disease; Myocardial ischemia

Exercise performance and quality of life in children with cystic fibrosis and mildly impaired lung function: relation with antibiotic treatments and hospitalization.

Patients with mild CF lung disease have good exercise performance although still lower than the normal population. VO2max% is affected by number of antibiotic treatments over a longer period. There is an impact of hospitalization days on quality of life. What is Known: • Children with CF have lower exercise performance; there is an association between hospitalization frequency and exercise performance • Quality of life is diminished in children with CF and influenced by respiratory infections What is New: • Even patients with mild CF lung disease have lower maximal exercise performance (VO 2 max) and a lower anaerobic threshold; VO 2 max is lower in children who had more antibiotic treatments in the last 3 years • School and emotional functioning are diminished in children with mild CF lung disease; hospitalization is negatively correlated with school functioning and physical functioning.

Poor Cardiac Function is Associated With Renal Injury Following EVAR

Poor Cardiac Function is Associated With Renal Injury Following EVAR

Relationship between exercise induced elevation of left ventricular filling pressure and exercise intolerance in patients with atrial fibrillation.

BackgroundElevated left ventricular filling pressure (LVFP) is an important cause of exercise intolerance in patients with atrial fibrillation (AF). Exercise stress echocardiography could assess LVFP during exercise. The objective of this study was to investigate the relationship between exercise induced elevation of LVFP and exercise capacity in patients with AF.MethodsThis study included 145 consecutive patients (81 men and 64 women; mean age 65.5 ± 8.0 years) with persistent non-valvular AF and normal left ventricular systolic function (left ventricular ejection fraction ≥ 50%). All patients underwent a symptom-limited cardiopulmonary exercise test (CPET). Doppler echocardiography was performed both at rest and immediately after exercise. Five consecutive measurements of early diastolic mitral inflow velocity (E) and early diastolic mitral annular velocity (e') were taken and averaged. E/e' ratio was calculated. Elevated LVFP was defined as E/e' > 9, and patients with elevated LVFP at rest were excluded.ResultsPatients were classified into two groups according to LVFP estimated by E/e' ratio after exercise: 39 (26.9%) with elevated LVFP after exercise and 106 (73.1%) with normal LVFP. As compared with patients with normal LVFP, the ones with elevated LVFP after exercise had significantly lower peak oxygen uptake (VO2 peak) (21.7 ± 2.3 vs. 26.4 ± 3.8 mL/min per kilogram, P < 0.001), lower anaerobic threshold (19.9 ± 2.5 vs. 26.0 ± 4.0 mL/min per kilogram, P < 0.001), and shorter exercise time duration (6.2 ± 0.8 vs. 7.0 ± 1.3 min, P < 0.001). Multivariate analysis showed that age, gender and E/e' after exercise were significantly correlated with VO2 peak.ConclusionElevated LVFP estimated by E/e' ratio after exercise is independently associated with reduced exercise capacity in AF patients.

Phenotyping Exercise Limitation in Systemic Sclerosis: The Use of Cardiopulmonary Exercise Testing

Background: Exercise impairment is a common symptom of systemic sclerosis (SSc), a disorder which is frequently complicated by cardiopulmonary involvement. Objectives: This study's aims were: (a) to define the prevalence and the potential causes of limited exercise capacity and (b) to study potential differences in clinical, radiological and functional characteristics and blood serology among SSc patients with exercise limitation of different etiology. Methods: Prospectively collected data on SSc patients who had conducted full lung function testing, blood serology, thorax high-resolution computed tomography, Doppler echocardiogram and a maximal cardiopulmonary exercise testing (CPET) were retrospectively analyzed. Using a CPET algorithm, patients were characterized as having normal or subnormal exercise capacity (N), respiratory limitation (RL), left ventricular dysfunction (LVD) or pulmonary vasculopathy (PV). Group comparisons were conducted using either one-way ANOVA or the Kruskal-Wallis test. A p value <0.05 was considered significant. Results: The study population consisted of 78 patients (53.7 ± 13.7 years old; 10.3% male). PV was present in 32.1%, LVD in 25.6% and RL in 10.2%, while 32.1% of the patients constituted the N group. The presence of antisclero-70 antibodies, low anaerobic threshold and low peak exercise capacity measures could discriminate LVD from the other groups. Low end-tidal carbon dioxide pressure and its change from rest to anaerobic threshold could discriminate between the PV, LVD and N groups, while respiratory restriction along with ventilatory inefficiency indices could differentiate the RL group from the rest. Conclusions: The combined evaluation of CPET gas exchange patterns with baseline measurements could discriminate the causes of exercise limitation among SSc patients.

Assessment of left ventricular preload by cardiac magnetic resonance imaging predicts exercise capacity in adult operated tetralogy of Fallot: a retrospective study.

BackgroundThe optimal timing of pulmonary homograft valve replacement (PVR) is uncertain. Cardiopulmonary exercise testing (CPET) and cardiac magnetic resonance (CMR) are often used to guide the clinical decision for PVR in operated tetralogy of Fallot (TOF) patients with significant pulmonary regurgitation (PR). We aim to study the relationship between exercise capacity and CMR in these patients.MethodsThe study is a single-centre retrospective analysis of 36 operated TOF patients [median 21.4 (interquartile range 16.4, 26.4) years post-repair; 30 NYHA I, 6 NYHA II; median age 25.2 (interquartile range 19.5-31.7) years, 29 males] with significant PR on CMR who underwent CPET within 15 [median 2.0 (interquartile range 0.8-7.2)] months from CMR. CPET parameters were compared with 30 age- and sex-matched healthy controls [median age 27.8 (interquartile range 21.0-32.8) years; 24 males].ResultsPeak systolic blood pressure (177 versus 192 mmHg, p = 0.007), Mets (7.3 versus 9.9, p < 0.001), peak oxygen consumption (VO2max) (29.2 versus 34.5 ml/kg/min, p < 0.001) and peak oxygen pulse (11.0 versus 13.7 ml/beat, p = 0.003) were significantly lower in TOF group versus control. Univariate analyses showed negative correlation between PR fraction and anaerobic threshold. There was a positive correlation between indexed left (LV) and right (RV) ventricular end-diastolic volumes, as well as indexed LV and effective RV stroke volumes, on CMR and VO2max and Mets achieved on CPET. These remained significant after adjustment for age and sex.ConclusionsTOF subjects have near normal exercise capacity but significantly lower Mets, VO2max and peak oygen pulse achieved compared to controls. Increased PR fraction in TOF subjects was associated with lower anaerobic threshold. Higher indexed effective RV stroke volume, a measure of LV preload, was associated with higher VO2max and Mets achieved, and may potentially be used as a predictor of exercise capacity.

Pre-operative cardiopulmonary exercise testing predicts adverse post-operative events and non-progression to adjuvant therapy after major pancreatic surgery

BackgroundSurgery followed by chemotherapy is the primary modality of cure for patients with resectable pancreatic cancer but is associated with significant morbidity. The aim of the present study was to evaluate the role of cardiopulmonary exercise testing (CPET) in predicting post-operative adverse events and fitness for chemotherapy after major pancreatic surgery. MethodsPatients who underwent a pancreaticoduodenectomy or total pancreatectomy for pancreatic head lesions and had undergone pre-operative CPET were included in this retrospective study. Data on patient demographics, comorbidity and results of pre-operative evaluation were collected. Post-operative adverse events, hospital stay and receipt of adjuvant therapy were outcome measures. ResultsOne hundred patients were included. Patients with an anaerobic threshold less than 10ml/kg/min had a significantly greater incidence of a post-operative pancreatic fistula [International Study Group for Pancreatic Surgery (ISGPS) Grades A–C, 35.4% versus 16%, P = 0.028] and major intra-abdominal abscesses [Clavien–Dindo (CD) Grades III–V, 22.4% versus 7.8%, P = 0.042] and were less likely to receive adjuvant therapy [hazard ratio (HR) 6.30, 95% confidence interval (CI) 1.25–31.75, P = 0.026]. A low anaerobic threshold was also associated with a prolonged hospital stay (median 20 versus 14 days, P = 0.005) but not with other adverse events. DiscussionCPET predicts a post-operative pancreatic fistula, major intra-abdominal abscesses as well as length of hospital stay after major pancreatic surgery. Patients with a low anaerobic threshold are less likely to receive adjuvant therapy.

Skeletal Muscle Dysfunction in Idiopathic Pulmonary Arterial Hypertension

Despite improvements in survival with disease-targeted therapies, the majority of patients with pulmonary arterial hypertension (PAH) have persistent exercise intolerance that results from impaired cardiac function and skeletal muscle dysfunction. Our intent was to understand the molecular mechanisms mediating skeletal muscle dysfunction in PAH. A total of 12 patients with PAH and 10 matched control subjects were assessed. Patients with PAH demonstrated diminished exercise capacity (lower oxygen uptake max, lower anaerobic threshold and higher minute ventilation/CO2) compared with control subjects. Quadriceps muscle cross-sectional area was significantly smaller in patients with PAH. The vastus lateralis muscle was biopsied to enable muscle fiber morphometric assessment and to determine expression levels/activation of proteins regulating (1) muscle mass, (2) mitochondria biogenesis and shaping machinery, and (3) excitation-contraction coupling. Patients with PAH demonstrated a decreased type I/type II muscle fiber ratio, with a smaller cross-sectional area in the type I fibers. Diminished AKT and p70S6 kinase phosphorylation, with increased atrogin-1 and muscle RING-finger protein-1 transcript levels, were evident in the PAH muscle, suggesting engagement of cellular signaling networks stimulating ubiquitin-proteasome-mediated proteolysis of muscle, with concurrent depression of networks mediating muscle hypertrophy. Although there were no differences in expression/activation of proteins associated with mitochondrial biogenesis or fission (MTCO2 [cytochrome C oxidase subunit II]/succinate dehydrogenase flavoprotein subunit A, mitochondrial transcription factor A, nuclear respiratory factor-1/dynamin-related protein 1 phosphorylation), protein levels of a positive regulator of mitochondrial fusion, Mitofusin2, were significantly lower in patients with PAH. Patients with PAH demonstrated increased phosphorylation of ryanodine receptor 1 receptors, suggesting that altered sarcoplasmic reticulum Ca(++) sequestration may impair excitation-contraction coupling in the PAH muscle. These data suggest that muscle dysfunction in PAH results from a combination of muscle atrophy and intrinsically impaired contractility.

Risk stratification by pre-operative cardiopulmonary exercise testing improves outcomes following elective abdominal aortic aneurysm surgery: a cohort study.

BackgroundIn 2009, the NHS evidence adoption center and National Institute for Health and Care Excellence (NICE) published a review of the use of endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs). They recommended the development of a risk-assessment tool to help identify AAA patients with greater or lesser risk of operative mortality and to contribute to mortality prediction.A low anaerobic threshold (AT), which is a reliable, objective measure of pre-operative cardiorespiratory fitness, as determined by pre-operative cardiopulmonary exercise testing (CPET) is associated with poor surgical outcomes for major abdominal surgery. We aimed to assess the impact of a CPET-based risk-stratification strategy upon perioperative mortality, length of stay and non-operative costs for elective (open and endovascular) infra-renal AAA patients.MethodsA retrospective cohort study was undertaken. Pre-operative CPET-based selection for elective surgical intervention was introduced in 2007. An anonymized cohort of 230 consecutive infra-renal AAA patients (2007 to 2011) was studied. A historical control group of 128 consecutive infra-renal AAA patients (2003 to 2007) was identified for comparison.Comparative analysis of demographic and outcome data for CPET-pass (AT ≥ 11 ml/kg/min), CPET-fail (AT < 11 ml/kg/min) and CPET-submaximal (no AT generated) subgroups with control subjects was performed. Primary outcomes included 30-day mortality, survival and length of stay (LOS); secondary outcomes were non-operative inpatient costs.ResultsOf 230 subjects, 188 underwent CPET: CPET-pass n = 131, CPET-fail n = 35 and CPET-submaximal n = 22. When compared to the controls, CPET-pass patients exhibited reduced median total LOS (10 vs 13 days for open surgery, n = 74, P < 0.01 and 4 vs 6 days for EVAR, n = 29, P < 0.05), intensive therapy unit requirement (3 vs 4 days for open repair only, P < 0.001), non-operative costs (£5,387 vs £9,634 for open repair, P < 0.001) and perioperative mortality (2.7% vs 12.6% (odds ratio: 0.19) for open repair only, P < 0.05). CPET-stratified (open/endovascular) patients exhibited a mid-term survival benefit (P < 0.05).ConclusionIn this retrospective cohort study, a pre-operative AT > 11 ml/kg/min was associated with reduced perioperative mortality (open cases only), LOS, survival and inpatient costs (open and endovascular repair) for elective infra-renal AAA surgery.

Double bypass for inoperable pancreatic malignancy at laparotomy: postoperative complications and long-term outcome.

INTRODUCTIONBetween 4% and 13% of patients with operable pancreatic malignancy are found unresectable at the time of surgery. Double bypass is a good option for fit patients but it is associated with high risk of postoperative complications. The aim of this study was to identify pre-operatively which patients undergoing double bypass are at high risk of complications and to assess their long-term outcome.METHODSOf the 576 patients undergoing pancreatic resections between 2006 and 2011, 50 patients who underwent a laparotomy for a planned pancreaticoduodenectomy had a double bypass procedure for inoperable disease. Demographic data, risk factors for postoperative complications and pre-operative anaesthetic assessment data including the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) and cardiopulmonary exercise testing (CPET) were collected.RESULTSFifty patients (33 men and 17 women) were included in the study. The median patient age was 64 years (range: 39–79 years). The complication rate was 50% and the in-hospital mortality rate was 4%. The P-POSSUM physiology subscore and low anaerobic threshold at CPET were significantly associated with postoperative complications (p=0.005 and p=0.016 respectively) but they were unable to predict them. Overall long-term survival was significantly shorter in patients with postoperative complications (9 vs 18 months). Postoperative complications were independently associated with poorer long-term survival (p=0.003, odds ratio: 3.261).CONCLUSIONSP-POSSUM and CPET are associated with postoperative complications but the possibility of using them for risk prediction requires further research. However, postoperative complications following double bypass have a significant impact on long-term survival and this type of surgery should therefore only be performed in specialised centres.