Vainshelboim B; Rao S; Chan K; Lima RM; Ashley EA; Myers J

Canadian Journal Of Anaesthesia [Can J Anaesth] 2017 Apr 05. Date of Electronic Publication: 2017 Apr 05.

Purpose: The ventilatory threshold (VT) is an objective physiological marker of the capacity of aerobic endurance that has good prognostic applications in preoperative settings. Nevertheless, determining the VT can be challenging due to physiological and methodological issues, especially in evaluating surgical risk. The purpose of the current study was to compare different methods of determining VT and to highlight the implications for assessing perioperative risk.
Methods: Our study entailed analysis of 445 treadmill cardiopulmonary exercise tests from 140 presurgical candidates with an aortic abdominal aneurysm (≥3.0 to ≤5.0 cm) and a mean (standard deviation [SD]) age of 72 (8) yr. We used three methods to determine the VT in 328 comparable tests, namely, self-detected metabolic system (MS), experts’ visual (V) readings, and software using a log-log transformation (LLT) of ventilation vs oxygen uptake. Differences and agreement between the three methods were assessed using analysis of variance (ANOVA), coefficient of variation (CV), typical error limits of agreement (LoA), and interclass correlation coefficients (ICC).
Results: Overall, ANOVA revealed significant differences between the methods [MS = 14.1 (4.3) mLO2·kg-1·min-1; V = 14.6 (4.4) mLO2·kg-1·min-1; and LLT = 12.3 (3.3) mLO2·kg-1·min-1; P < 0.001]. The assessment of agreement between methods provided the following results: ICC = 0.85; 95% confidence interval (CI), 0.82 to 0.87; P < 0.001; typical error, 2.1-2.8 mLO2·kg-1·min-1; and, 95% LoA and CV ranged from 43 to 55% and 15.9 to 19.6%, respectively. Conclusions: The results show clinically significant variations between the methods and underscore the challenges of determining VT for perioperative risk stratification. The findings highlight the importance of meticulous evaluation of VT for predicting surgical outcomes. Future studies should address the prognostic perioperative utility of computed mathematical models combined with an expert's review. This trial was registered at ClinicalTrials.gov, identifier: NCT00349947.

Ozemek C; Whaley MH; Finch WH;Kaminsky LA;

European Journal Of Sport Science [Eur J Sport Sci] 2017 Jun; Vol. 17 (5), pp. 563-570. Date of Electronic Publication: 2017 Jan 18

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HRmax) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HRmax with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18-76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HRmax for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R2 (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HRmax explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HRmax.

Sveric KM, Ulbrich S, Rady M, Ruf T, Kvakan H, Strasser RH, Jellinghaus S

Circ J. 2017 Mar 24;81(4):529-536. doi: 10.1253/circj.CJ-16-0965. Epub 2017 Jan
24. (Article from Dresden)

BACKGROUND: LV twist has a key role in maintaining left ventricular (LV)
contractility during exercise. The purpose of this study was to investigate LV
torsion instead of twist as a surrogate marker of peak oxygen uptake (peak V̇O2)
assessed by cardiopulmonary exercise testing (CPET) in patients with non-ischemic
dilated cardiomyopathy (DCM).Methods and Results:We evaluated 45 outpatients with
DCM (50±12 years, 24% females) with 3D speckle-tracking electrocardiography prior
to CPET. LV torsion, LV ejection fraction (EF), LV diastolic function, LV global
longitudinal (GLS) and circumferential (GCS) strain were quantified. A reduced
functional capacity (FC) was defined as a peak V̇O2<20 mL/kg/min. LV torsion correlated most strongly with peak V̇O2(r=0.76, P<0.001). LV torsion instead of twist was an independent predictor of peak V̇O2(B: 0.59 to 0.71, P<0.001) in multivariable analyses. Impaired LV torsion <0.61 degrees/cm was able to predict a reduced FC with higher sensitivity and specificity (0.91 and 0.81; area under the curve (AUC): 0.88, P<0.001) than LV EF, GLS or GCS (AUC 0.64, 0.63 and 0.66; P<0.05 for differences in AUC). CONCLUSIONS: Peak V̇O2 correlated more strongly with LV torsion than with LV diastolic function, LV EF, GLS or GCS. LV torsion had high accuracy in identifying patients with a reduced FC.

Takken T, Bongers BC, van Brussel M, Haapala EA, Hulzebos EH

Ann Am Thorac Soc. 2017 Apr 11. doi: 10.1513/AnnalsATS.201611-912FR. [Epub ahead
of print] (Article from Netherlands)

Aerobic fitness is an important determinant of overall health. Higher aerobic
fitness has been associated with many health benefits. Because myocardial
ischemia is rare in children, indications for exercise testing differ in children
compared to adults. Pediatric exercise testing is imperative to unravel the
physiological mechanisms of a reduced aerobic fitness and to evaluate
intervention effects in children and adolescents with a chronic disease or
disability. Cardiopulmonary exercise testing includes the measurement of
respiratory gas exchange and is the gold standard for determining aerobic
fitness, as well as for examining the integrated physiological responses to
exercise in pediatric medicine. As the physiological responses to exercise change
during growth and development, appropriate pediatric reference values are
essential for an adequate interpretation of the cardiopulmonary exercise test.

Kahn SR, Akaberi A, Granton JT, Anderson DR, Wells PS, Rodger MA, Solymoss S, Kovacs MJ, Rudski L, Shimony A, Dennie C, Rush C, Hernandez P, Aaron SD, Hirsch AM (article from Montreal Canada)

Am J Med. 2017 Apr 8. pii: S0002-9343(17)30361-3. doi:
10.1016/j.amjmed.2017.03.033. [Epub ahead of print]

BACKGROUND: We aimed to evaluate health-related quality of life (QOL), dyspnea
and functional exercise capacity during the year following the diagnosis of a
first episode of pulmonary embolism.
METHODS: Prospective multicenter cohort study of 100 patients with acute
pulmonary embolism recruited at 5 Canadian hospitals from 2010-2013. We measured
the outcomes QOL (by SF-36 and PEmb-QOL measures), dyspnea (by the University of
California San Diego Shortness of Breath Questionnaire (SOBQ)) and six-minute
walk distance at Baseline, 1, 3, 6, and 12 months after acute pulmonary embolism.
CT pulmonary angiography was performed at baseline, echocardiogram was performed
within 10 days, and cardiopulmonary exercise testing was performed at 1 and 12
months. Predictors of change in QOL, dyspnea, and six-minute walk distance were
assessed by repeated measures mixed effects models analysis.
RESULTS: Mean age was 50.0 years, 57% were male, and 80% were treated as
out-patients. Mean scores for all outcomes improved during 1 year follow-up: from
baseline to 12 months, mean SF-36 physical component score improved by 8.8
points, SF-36 mental component score by 5.3 points, PEmb-QoL by -32.1 points, and
SOBQ by -16.3 points, and six-minute walk distance improved by 40 m. Independent
predictors of reduced improvement over time were female sex, higher BMI and
percent-predicted VO2 peak <80% on 1 month cardiopulmonary exercise test for all outcomes; prior lung disease and higher pulmonary artery systolic pressure on 10-day echocardiogram for the outcomes SF-36 physical component score and dyspnea score; and higher main pulmonary artery diameter on baseline CT pulmonary angiography for the outcome PEmb-QoL score. CONCLUSIONS: On average, QOL, dyspnea, and walking distance improve during the year after pulmonary embolism. However, a number of clinical and physiological predictors of reduced improvement over time were identified, most notably female sex, higher BMI and exercise limitation on 1- month cardiopulmonary exercise test. Our results provide new information on patient-relevant prognosis after pulmonary embolism.

Key A, Parry , West MA, Asher R, Jack S, Duffy N, Torella F, Walker PP.

BMJ Open Respir Res. 2017 Apr 5;4(1):e000164. doi: 10.1136/bmjresp-2016-000164.
eCollection 2017

INTRODUCTION: β Blockers are important treatment for ischaemic heart disease and
heart failure; however, there has long been concern about their use in people
with chronic obstructive pulmonary disease (COPD) due to fear of symptomatic
worsening of breathlessness. Despite growing evidence of safety and efficacy,
they remain underused. We examined the effect of β-blockade on lung function,
exercise performance and dynamic hyperinflation in a group of vascular surgical
patients, a high proportion of who were expected to have COPD.
METHODS: People undergoing routine abdominal aortic aneurysm (AAA) surveillance
were sequentially recruited from vascular surgery clinic. They completed
plethysmographically measured lung function and incremental cardiopulmonary
exercise testing with dynamic measurement of inspiratory capacity while taking
and not taking β blocker.
RESULTS: 48 participants completed tests while taking and not taking β blockers
with 38 completing all assessments successfully. 15 participants (39%) were found
to have, predominantly mild and undiagnosed, COPD. People with COPD had airflow
obstruction, increased airway resistance (Raw) and specific conductance (sGaw),
static hyperinflation and dynamically hyperinflated during exercise. In the whole
group, β-blockade led to a small fall in FEV1 (0.1 L/2.8% predicted) but did not
affect Raw, sGaw, static or dynamic hyperinflation. No difference in response to
β-blockade was seen in those with and without COPD.
CONCLUSIONS: In people with AAA, β-blockade has little effect on lung function
and dynamic hyperinflation in those with and without COPD. In this population,
the prevalence of COPD is high and consideration should be given to case finding
with spirometry.
TRIAL REGISTRATION NUMBER: NCT02106286.

Onofre T, Carlos R, Oliver N, Felismino A, Fialho D, Corte R,
da Silva EP, Godoy E, Bruno S

Obes Surg. 2017 Apr 7. doi: 10.1007/s11695-017-2584-y. [Epub ahead of print]

BACKGROUND: In severely obese individuals, reducing body weight induced by
bariatric surgery is able to promote a reduction in comorbidities and improve
respiratory symptoms. However, cardiorespiratory fitness (CRF) reflected by peak
oxygen uptake (VO2peak) may not improve in individuals who remain sedentary
post-surgery. The objective of this study was to evaluate the effects of a
physical training program on CRF and pulmonary function in obese women after
bariatric surgery, and to compare them to a control group.
METHODS: Twelve obese female candidates for bariatric surgery were evaluated in
the preoperative, 3 months postoperative (3MPO), and 6 months postoperative
(6MPO) periods through anthropometry, spirometry, and cardiopulmonary exercise
testing (CPX). In the 3MPO period, patients were divided into control group (CG,
n = 6) and intervention group (IG, n = 6). CG received only general guidelines
while IG underwent a structured and supervised physical training program
involving aerobic and resistance exercises, lasting 12 weeks.
RESULTS: All patients had a significant reduction in anthropometric measurements
and an increase in lung function after surgery, with no difference between
groups. However, only IG presented a significant increase (p < 0.05) in VO2peak and total CPX duration of 5.9 mL/kg/min (23.8%) and 4.9 min (42.9%), respectively. CONCLUSIONS: Applying a physical training program to a group of obese women after 3 months of bariatric surgery could promote a significant increase in CRF only in the trained group, yet also showing that bariatric surgery alone caused an improvement in the lung function of both groups.

O’Byrne ML, Desai S, Lane M, McBride M, Paridon S, Goldmuntz E.

Pediatr Cardiol. 2017;38(3):472-483.

Increasing habitual exercise has been associated with improved cardiopulmonary exercise testing (CPET) performance, specifically maximal oxygen consumption in children with operatively corrected congenital heart disease. This has not been studied in children following Fontan palliation, a population in whom CPET performance is dramatically diminished. A single-center cross-sectional study with prospective and retrospective data collection was performed that assessed habitual exercise preceding a clinically indicated CPET in children and adolescents with Fontan palliation, transposition of the great arteries following arterial switch operation (TGA), and normal cardiac anatomy without prior operation. Data from contemporaneous clinical reports and imaging studies were collected. The association between percent predicted VO2max and habitual exercise duration adjusted for known covariates was tested. A total of 175 subjects (75 post-Fontan, 20 with TGA, and 80 with normal cardiac anatomy) were enrolled. VO2max was lower in the Fontan group than patients with normal cardiac anatomy (p < 0.0001) or TGA (p < 0.0001). In Fontan subjects, both univariate and multivariate analysis failed to demonstrate a significant association between habitual exercise and VO2max (p = 0.6), in sharp contrast to cardiac normal subjects. In multivariate analysis, increasing age was the only independent risk factor associated with decreasing VO2max in the Fontan group (p = 0.003). Habitual exercise was not associated with VO2max in subjects with a Fontan as compared to biventricular circulation. Further research is necessary to understand why their habitual exercise is ineffective and/or what aspects of the Fontan circulation disrupt this association.

O’Byrne ML; Desai S; Lane M; McBride M; Paridon S; Goldmuntz E

Pediatric Cardiology [Pediatr Cardiol], ISSN: 1432-1971, 2017 Mar; Vol. 38 (3), pp. 472-483

Increasing habitual
exercise has been associated with improved cardiopulmonary exercise
testing (CPET) performance, specifically maximal oxygen consumption in
children with operatively corrected congenital heart disease. This has
not been studied in children following Fontan palliation, a population
in whom CPET performance is dramatically diminished. A single-center
cross-sectional study with prospective and retrospective data
collection was performed that assessed habitual exercise preceding a
clinically indicated CPET in children and adolescents with Fontan
palliation, transposition of the great arteries following arterial
switch operation (TGA), and normal cardiac anatomy without prior
operation. Data from contemporaneous clinical reports and imaging
studies were collected. The association between percent predicted
VO2max and habitual exercise duration adjusted for known covariates was
tested. A total of 175 subjects (75 post-Fontan, 20 with TGA, and 80
with normal cardiac anatomy) were enrolled. VO2max was lower in the
Fontan group than patients with normal cardiac anatomy (p < 0.0001) or TGA (p < 0.0001). In Fontan subjects, both univariate and multivariate analysis failed to demonstrate a significant association between habitual exercise and VO2max (p = 0.6), in sharp contrast to cardiac normal subjects. In multivariate analysis, increasing age was the only independent risk factor associated with decreasing VO2max in the Fontan group (p = 0.003). Habitual exercise was not associated with VO2max in subjects with a Fontan as compared to biventricular circulation. Further research is necessary to understand why their habitual exercise is ineffective and/or what aspects of the Fontan circulation disrupt this association.

Swart M, Carlisle JB, Goddard J.

Br J Anaesth. 2017;118(1):100-104.

BACKGROUND: Preoperative identification of high-risk surgical patients might help to reduce postoperative morbidity and mortality. Using a patient’s predicted 30 day mortality to plan postoperative high-dependency unit (HDU) care after elective colorectal surgery might be associated with reduced postoperative morbidity.
METHODS: The 30 day postoperative mortality was predicted for 504 elective colorectal surgical patients in a preoperative clinic. The prediction was used to determine postoperative surgical ward or HDU care. Those with a predicted 30 day mortality of 1-3% mortality, and thus deemed at intermediate risk, had either planned HDU care (n=68) or planned ward care (n=139). The main outcome measures were emergency laparotomy and unplanned critical care admission.
RESULTS: There were more emergency laparotomies and unplanned critical care admissions in patients with a predicted 30 day mortality of 1-3% who went to an HDU after surgery compared with patients who went to a ward: 0 vs 14 (10%), P=0.0056 and 0 vs 22 (16%), P=0.0002, respectively.
CONCLUSIONS: Planned postoperative critical care was associated with a lower rate of complications after elective colorectal surgery.