Task Force II: Determination of occupational working capacity in patients with ischemic heart disease

Work resumption after invasive heart procedures, rehabilitation and ergonomic evaluation: from the hospital to the workplace

Our Institute adopts a multidisciplinary protocol named "CardioWork" for work resumption after invasive cardiac procedures and subsequent rehabilitation: after evaluation of the cardiac functional profile, the occupational physician analyses the work activity prior to the cardiopathological event, identifies the presumed task energy requirement (from specific, published tables), and compares it with the exercise test results. Indications regarding timing and modality of returning to work are formulated accordingly. To verify the reliability of the indications thus provided, we carried out a clinical-functional follow-up study in the workplace, with Holter ECG and Armband measurement of actual energy expenditure. Over the course of two years, we enrolled 36 patients (mostly males, aged between 30 and 70 years), hospitalized after coronary revascularization, valve replacement or cardiac defibrillator implant. After rehabilitation, instrumental diagnostics (Holter ECG, echocardiography, exercise test) showed discrete functional conditions, with better values with regard to cardiac function than exercise capacity and effort tolerance. All subjects were judged fit for the job, in most cases with limitations concerning ergonomic factors, working timetable and/or stress. They returned to work quickly, with good adherence to the indications provided. Workplace Holter ECG did not show appreciable differences compared to the hospital evaluation. In one case, the average energy expenditure measured while working was higher than that inferred from the tables; in the remaining subjects, the actual expenditure coincided with what was expected or was lower. In a minority of cases (39%), the measured average expenditure slightly exceeded the optimal value (35% of the maximal value at the exercise test) recommended at the time of hospital discharge. At the end of the workplace evaluation, it was not necessary to formulate new indications. The study provides further evidence of the effectiveness of the CardioWork protocol in promoting return to work after invasive heart procedures. Though they need continuous updating, the published estimates of presumed task energy requirement remain reliable. In particularly complex cases, it is however advisable to carry out a field check of the ergometric assessments performed at the end of rehabilitation.

Cardiovascular risk in high-hazard occupations: the role of occupational cardiology

Work is beneficial for health, but many individuals develop cardiovascular disease (CVD) during their working lives. Occupational cardiology is an emerging field that combines traditional cardiology sub-specialisms with prevention and risk management unique to specific employment characteristics and conditions. In some occupational settings incapacitation through CVD has the potential to be catastrophic due to the nature of work and/or the working environment. These are often termed 'hazardous' or 'high-hazard' occupations. Consequently, many organizations that employ individuals in high-hazard roles undertake pre-employment medicals and periodic medical examinations to screen for CVD. The identification of CVD that exceeds predefined employer (or regulatory body) risk thresholds can result in occupational restriction, or disqualification, which may be temporary or permanent. This article will review the evidence related to occupational cardiology for several high-hazard occupations related to aviation and space, diving, high altitude, emergency workers, commercial transportation, and the military. The article will focus on environmental risk, screening, surveillance, and risk management for the prevention of events precipitated by CVD. Occupational cardiology is a challenging field that requires a broad understanding of general cardiology, environmental, and occupational medicine principles. There is a current lack of consensus and contemporary evidence which requires further research. Provision of evidence-based, but individualized, risk stratification and treatment plans is required from specialists that understand the complex interaction between work and the cardiovascular system. There is a current lack of consensus and contemporary evidence in occupational cardiology and further research is required.

The importance of return to work: How to achieve optimal reintegration in ACS patients

The vocational reintegration of patients after an acute coronary syndrome is a crucial step towards complete convalescence from the social as well as the individual point of view. Return to work rates are determined by medical parameters such as left ventricular function, residual ischaemia and heart rhythm stability, as well as by occupational requirement profile such as blue or white collar work, night shifts and the ability to commute (which is, in part, determined by physical fitness). Psychosocial factors including depression, self-perceived health situation and pre-existing cognitive impairment determine the reintegration rate to a significant extent. Patients at risk of poor vocational outcomes should be identified in the early period of rehabilitation to avoid a reintegration failure and to prevent socio-professional exclusion with adverse psychological and financial consequences. A comprehensive healthcare pathway of acute coronary syndrome patients is initiated by cardiac rehabilitation, which includes specific algorithms and assessment tools for risk stratification and occupational restitution. As the first in its kind, this review addresses determinants and legal aspects of reintegration of patients experiencing an acute coronary syndrome, and offers practical advice on reintegration strategies particularly for vulnerable patients. It presents different approaches and scientific findings in the European countries and serves as a recommendation for action.

[Exercise-induced coronary thrombosis]

Heavy exertion as a trigger of cardiac events has been known since antiquity as it was already described in 492 BC in the famous Athens Marathon. Myocardial infarction occurring after physical exertion accounts for about 4% of myocardial infarctions. It is more common in men and younger patients. It usually occurs during intense efforts and especially in inactive people with multiple risk factors. It would be more severe with more frequent Q waves of necrosis on the victims' electrocardiograms, with greater troponin release and a more raised GRACE score. Atherosclerotic plaque rupture is at the center of its pathophysiology, this event is responsible of a thrombus formation occluding the coronary artery. The hemodynamic stress imposed on the often-atheromatous coronary arteries during exercise, favor the plaque rupture and the occurrence of myocardial infarctions. To these hemodynamic constraints, are added biochemical and rheological modifications, which favor the formation of an intra-coronary thrombus. The occurrence of acute coronary events during heavy exertion in patients who are often untrained must not make us forget about the benefit of regular exercise on both the life quality and morbimortality levels.

Physical activity and 22-year all-cause and coronary heart disease mortality

BACKGROUND

This study explores the effects of occupational (OPA) and leisure time physical activity (LTPA) on mortality relative to cardiorespiratory fitness and pre-existing coronary heart disease (CHD).

METHODS

Associations between OPA, measured as energy expenditure (kcal/day) and relative aerobic workload (%VO₂ max), LTPA, and 22-year mortality among 1891 Finnish men were assessed by Cox regression models stratified by CHD and adjusted for 19 confounders.

RESULTS

In fully adjusted models, each 10% of relative aerobic workload increased all-cause mortality by 13% and CHD mortality 28% (P < 0.01). Compared to healthy subjects, men with CHD experienced lower mortality risks due to OPA and higher risks due to LTPA. While LTPA had no effect among healthy men, in men with CHD each weekly hour of conditioning LTPA increased all-cause mortality risks by 10% and CHD mortality by14%.

CONCLUSION

OPA was positively associated with both all-cause and CHD mortality. LTPA was not protective. Among men with CHD, LTPA increased mortality risks.

Single coronary artery originating from the right sinus Valsalva and ability to work

We present a case of a 56-year-old male electrician who was admitted to the hospital with atrial fibrillation, atypical chest pain and dyspnea. He gave a history that on the morning he had working for almost 4 hours carrying out various activities with considerable physical effort. After cardioversion, conventional coronary angiography revealed a suspect of single coronary vessel (SCA) arising from the right sinus of Valsalva. The patient underwent multislice computed tomography that showed a SCA arising from the right sinus Valsalva and dividing in Right Coronary Artery (RCA) and Left Main coronary artery (LM). The finding of posterior course of the LM without atherosclerotic has proved crucial for the expression of an opinion of working capacity even with limitation.

Cardiac risk of coronary patients after reintegration into occupations with heavy physical exertion

The job related reintegration of patients with coronary artery disease (CAD) is a central part of cardiac rehabilitation. However, specific occupational demands like jobs with heavy physical exertion (> 6 METs) could increase the cardiovascular risk because the relative risk for acute myocardial infarction (MI) and cardiac death is temporarily elevated after vigorous exertion ("hazard period"). Thus, in 2001 any male patient with proven CAD who performed a job with heavy exertion until the occurrence of an index event (MI/ACS, any interventional or surgical revascularization measure) received a questionnaire after an average of 20 months. Complete data were available in 108 from 119 included patients (90.8%), aged 51.8+/-7.8 years. Ejection fraction was 61.5+/-13.1% and the functional capacity at the time of hospital discharge averaged 130.1+/-31.2 W. 75% of the patients had a previous MI and 59.3% underwent bypass surgery. During follow-up the previous job with heavy exertion was performed over a cumulated time of 74 years. The aim of the study was to compare the observed and the expected incidence of MI and cardiac death with and without job performance. The expected ("basal") risk for MI and cardiac death without heavy physical exertion was determined from pooled study results and assumed to be 5.2% per year. The combined risk due to performing an occupation with strenuous exertion can be calculated from time periods with and without working hours and amounts to 11.9%. There could be expected 0.119 . 74=8.8 cardiac events related to the job. In contrast, 5 MIs (4 NSTEMI, 1 STEMI) were observed (6.8%). The relative risk for an expected event compared to the basal risk without heavy exertion was 2.3 (95% CI: 0.7-7.4). The relative risk for the observed cardiac events amounts to 1.3 (95% CI: 0.4-4.8). The lower observed risk is probably due to the high grade of physical fitness in this patient group. In spite of several limitations, our study showed no convincing evidence for increasing the cardiac risk of patients with CAD performing occupations with heavy physical exertion. Because of the importance of this prognostic finding, a representative and prospective study is strongly required.

A functional assessment methodology for alcohol dependent patients undergoing rehabilitative treatments

PURPOSE

We propose a functional assessment approach for patients with alcoholic dependence of working age undergoing aerobic training. The background is the WHO indication (ICIDH-2) to use measurable 'activities' as a means to assess the individual 'participation' in social life which also implies work capacity. Defining sustainable energetic levels for the individual is an important issue for both the quantification of an effective training and the evaluation of possible improvements following training.

METHODS

Fifty-six 'alcohol dependent' patients, as defined by DSM IV (Diagnostic and Statistical Manual of Mental Disorders), admitted to our Unit in a 16 month-period participated in the study. Eighteen healthy subjects served as controls (Group C). Out of all the 56 patients, 33 (Group A) underwent an aerobic training and 23 subjects (Group N) underwent the same pharmacological and psychological therapy but without aerobic training. Patients were assigned to the treatment (A) or no treatment (N) group according to a 'quasi-experimental' design (i.e. temporal selection criteria). The evaluation protocol consisted of submaximal symptom-limited tests. The tests consisted of bouts of 'basic' activities (walking, lifting, arm-work) to be performed at different intensities. We estimated the total energetic work (TW) performed in the tests by means of formulas available in the literature. The maximal energetic intensity (EI) reached during the tests was also estimated and expressed in MET (multiple of the basal metabolism).

RESULTS

Significant differences in work capacity were observed between patients and healthy subjects at baseline. Group A significantly increased TW after rehabilitation, while Group N did not increment their performance at the re-test.

CONCLUSIONS

The proposed approach could be useful in the functional assessment of deconditioned subjects with alcohol dependence in working age, and could monitor the changes in work capacity following training.

Predicting endurance limits in arm cranking exercise with a subjectively based method

The purpose of this study was to compare a method for predicting endurance capacity at different workloads based on subjective perception of effort with the technique for determining 'critical power' (CP) proposed by Moritani et al. (1981). Three trained paraplegic subjects performed two protocols during separate sessions. The 'subjective' protocol consisted of graded and continuous tests on an arm crank ergometer, during which cardiorespiratory (heart rate, oxygen consumption, ventilation and respiratory exchange ratio) and subjective (Borg's 10-point scale) parameters were monitored continuously. A statistical regression analysis for power functions was performed to obtain the individual ¿iso-perception' curves in a power/duration reference system. The other protocol consisted of the determination of the CP of the muscle groups involved in arm cranking exercises according to the protocol proposed by Moritani et al. (1981). Subjects performed three tests in which the power output remained constant (50, 37.5 and 25 W) and led to the onset of muscular fatigue. The results of the two protocols were compared. The validity of the subjective perception of effort as a predictor of individual endurance capacity was confirmed by the relationship between time to exhaustion and work performed during constant-power tests as proposed by Moritani et al. (1981).

Responses of people with coronary artery disease to common lawn-care tasks

The primary purpose of the present study was to determine oxygen uptake (VO2) and heart rate (HR) responses of patients with coronary artery disease (CAD) to common lawn-care activities. The study was conducted in three phases. In phase I, 8 men with CAD performed 30 min of push motorized lawn mowing at a self-paced rate. In phase II, 9 men with CAD performed push (no power) mowing, trimming (power and manual), and raking for 8 min each. In phase III, age-matched men and women with and without CAD (9-11 per group) performed self-propelled motorized mowing and push motorized mowing. In phase I, VO2 averaged 17.3 (SEM 3.8) ml.kg-1.min-1 during 30 min of mowing. Relative effort was 68 (SEM 1) and 76 (SEM 4)% of treadmill maximal VO2 (VO2max) and HR, respectively. In phase II, mean VO2 ranged from 8.6 (SEM 0.4) with grass trimming to 22.2 (SEM 1.6) ml.kg-1.min-1 with push manual mowing. With self-propelled mowing at three speeds in phase III, mean VO2 of the CAD groups ranged from 9.5 (SEM 0.3) to 13.8 (SEM 1.4) ml.kg-1.min-1 and represented 37%-62% VO2max. The results indicated that lawn mowing is often performed at an exercise intensity recommended for aerobic exercise training; patients who achieve a treadmill peak capacity of 4 times resting metabolic rate (4 METs) should be able to perform self-propelled motorized lawn mowing (slow speed) and grass trimming at less than 80% peak VO2; and VO2 demands of lawn mowing can be adjusted by equipment selection and/or pace.

[Return to work after myocardial revascularization]

Six hundred and seventy-two patients classified in four strata with one hundred sixty-eight in each were evaluated during the fourth month after myocardial revascularization, with coronary artery bypass graft and/or internal mammary artery and coronary angioplasty, in order to verify the return or not to work as well as the conditions under which this was done. The four strata constituted by occupational profile were the following: I--entrepreneurs and managers; II--professionals with university degree; III--technicians; IV--unskilled and semi-skilled professionals. The aim of this research project was to discover how variables like demographics, education, procedure and support after procedure, were related to the return to work. Return to work did not occur in 20.8% of all cases. The non-return contingent in each of the four strata was the following: I = 11.9%; II = 15.5%; III = 26.2% and IV = 29.8%. Among those submitted to angioplasty the proportion of non-return was lower than that of those submitted to surgery.

Identification of patients with coronary disease at high risk for loss of employment. A prospective validation study

BACKGROUND

Work disability is common in patients with coronary artery disease and adversely affects both economic well-being and quality of life. The purpose of this study was to construct a model to predict premature departure from the work force of patients with coronary disease and to validate this model prospectively in an independent cohort of patients.

METHODS AND RESULTS

We enrolled 1,252 coronary disease patients referred for diagnostic cardiac catheterization who were less than age 65, employed, and without prior coronary angioplasty or coronary bypass surgery. Medical, functional, psychological, economic, and job-related variables were measured at the time of baseline diagnostic cardiac catheterization, and all patients were followed for 1 year. Three hundred twelve patients underwent percutaneous transluminal coronary angioplasty (PTCA) within 60 days of catheterization, and 449 had coronary artery bypass graft surgery (CABG) within 60 days of catheterization. The remaining 491 patients were treated with initial medical therapy. Logistic regression was used to develop a multivariable model for predicting 1-year work status in the training sample patients (872 patients enrolled between March 1986 and February 1989). This model was then validated in the independent prospective test sample (380 patients enrolled between March 1989 and June 1990). Eight factors were independent predictors of departure from the work force: lower initial functional status (as assessed by the Duke Activity Status Index), followed by older age, black race, presence of congestive heart failure, lower education level, presence of extracardiac vascular disease, poorer psychological status, and lower job classification. Standard clinical variables provided only 20% of the total predictive information available from the model about follow-up work outcomes, whereas functional measures provided 27%, and demographic and socioeconomic measures provided 45%. In the test sample, the area under the receiver operating characteristic curve for the model predictions was 0.74, compared with 0.80 in the training sample, and model predictions agreed well with observed prevalences of return to work. After adjustment for baseline imbalances, there was no significant difference in 1-year return-to-work rates among the patients receiving initial PTCA or CABG therapy versus initial medical therapy.

CONCLUSIONS

Patients with coronary disease who are at high risk for premature departure from the work force can be accurately identified from a combination of medical and nonmedical risk factors. The model developed in this study provides a tool to identify patients at high risk for premature loss from the work force. Such patients may benefit from special multidimensional intervention programs designed to preserve work status. Our data show that revascularization with either PTCA or CABG is not, by itself, sufficient to accomplish this goal.

Cardiac response to combined moderate heat and exercise in men with coronary artery disease

The effect of moderate heat stress on cardiac performance during sustained moderate physical work was evaluated in men greater than or equal to 6 weeks after a cardiac event. Subjects (n = 10) performed upright leg cycle ergometer exercise at approximately 50% of peak oxygen uptake for up to 60 minutes in warm (30.0 +/- 0.9 degrees C) and thermoneutral (21.5 +/- 0.3 degrees C) environments. Cardiac output (carbon dioxide rebreathing method), left ventricular ejection fraction and relative left ventricular end-diastolic volume (portable nuclear VEST monitor) were periodically determined. In both environments, heart rate increased (p less than 0.05), stroke volume decreased (p less than 0.05), and cardiac output remained unchanged with exercise time. In the warmer environment, heart rate was increased (p less than 0.05) and stroke volume tended to be decreased (p less than 0.08), with no difference in cardiac output. In both environments, left ventricular ejection fraction did not change from minute 6 to 60 of exercise, whereas relative left ventricular end-diastolic volume decreased (p less than 0.05) with exercise time. Arterial blood pressure was unchanged from minute 6 to 60 in the warm environment. Arrhythmias were not altered by exercise time or environment, and no subjects had evidence of myocardial ischemia. The data indicate that although heart rate increased and stroke volume and relative left ventricular end-diastolic volume decreased with exercise time, cardiac output and left ventricular ejection fraction remained unchanged in both thermoneutral and warm environments.(ABSTRACT TRUNCATED AT 250 WORDS)