Preoperative evaluation of cardiac failure and ischemia in elderly patients by cardiopulmonary exercise testing

Major surgery in the elderly continues to have a high mortality rate. Preoperative myocardial ischemia is a known risk factor. Cardiac failure is also a risk factor, but is difficult to quantify objectively. One hundred eighty-seven elderly surgical patients were evaluated for cardiac failure by cardiopulmonary exercise testing (CPX). The overall mortality in these patients was 7.5 percent. If three deaths secondary to surgical causes are excluded, mortality was 5.9 percent. There were 55 patients in whom the anaerobic threshold (AT) was less than 11 ml/min/kg; of these, 10 died, a mortality rate of 18 percent. There were 132 patients with an AT of greater than 11 ml/min/kg and of these, 1 patient died, giving a mortality rate of 0.8 percent (p < 0.001). A low AT associated with preoperative ischemia resulted in the death of 8 of 19 patients, a mortality rate of 42 percent. When the ischemia was associated with the higher AT, then 1 patient out of 25 died, a mortality rate of 4 percent (p < 0.01). Both preoperative ischemia and preoperative cardiac failure are independent risk factors for perioperative mortality in the elderly.     

The role of cardiopulmonary exercise testing in lung and heart-lung transplantation

Cardiopulmonary exercise testing in recipients of lung and heart-lung transplants demonstrates significant restoration of exercise tolerance to individuals severely disabled by their underlying cardiopulmonary disease. Recipients can perform moderate levels of activity compatible with a normal lifestyle. Considerable exercise limitation, however, remains in most recipients as measured by maximum oxygen uptake and work rate, despite substantial improvement and often normalization in resting cardiopulmonary function. The amount of exercise limitation observed in recipients of single-lung, bilateral-lung, and heart-lung transplants is interestingly similar, and the pattern of limitation is somewhat stereotyped. Ventilatory abnormalities are never limiting. Gas exchange abnormalities are sometimes seen (especially in single-lung transplant recipients) but generally are not limiting. Cardiac dysfunction is sometimes seen (particularly in heart-lung transplant recipients) but also does not appear to be limiting. Peripheral factors limiting exercise (which may include abnormalities in the peripheral circulation and peripheral neuromuscular structure and function) are almost universally seen and are probably the primary determinant of exercise limitation in these patients. At present, the relative contributions of various peripheral factors to exercise limitation are unclear. Further study may help elucidate these issues.     

Invasive exercise testing in the evaluation of patients at high-risk for lung resection

The aim of this study was to investigate whether invasive exercise testing with gas exchange and pulmonary haemodynamic measurements could contribute to the preoperative assessment of patients with lung cancer at a high-risk for lung resection. Sixty-five patients scheduled for thoracotomy (aged 66+/-8 yrs (mean+/-SD), 64 males, forced expiratory volume in one second (FEV1) 54+/-13% predicted) were studied prospectively. High risk was defined on the basis of predicted postpneumonectomy (PPN) FEV1 and/or carbon monoxide diffusing capacity of the lung (DL,CO) <40% pred. Arterial blood gas measurements were performed in all patients at rest and during exercise. In 46 patients, pulmonary haemodynamic measurements were also performed at rest and during exercise. Predicted postoperative (PPO) values for FEV1 and DL,CO were calculated according to quantitative lung scanning and the amount of resected parenchyma. There were four postoperative deaths (6.2% mortality rate) and postoperative cardiorespiratory complications developed in 31 (47.7%) patients. Patients with respiratory complications only differed from patients without or with minimal (arrhythmia) complications in FEV1,PPO. Peak O2 uptake and haemodynamic variables were similar in both groups. The four patients who died had a lower FEV1,PPO, a lower DL,CO,PPO and a greater decrease in arterial oxygen tension during exercise, compared with the remaining patients. In conclusion, the forced expiratory volume in one second, together with the extent of parenchymal resection and perfusion of the affected lung, are useful parameters to identify patients at greatest risk of postoperative complications among those at a high-risk for lung resection. In these patients, pulmonary haemodynamic measurements appear to have no discriminatory value, whereas gas exchange measurements during exercise may help to identify patients with higher mortality risk.     

Treadmill exercise duration and dyspnea recovery time in chronic obstructive pulmonary disease: effects of oxygen breathing and repeated testing

OBJECTIVES: To evaluate biochemical outcome after definitive radiotherapy as a function of family history groupings. METHODS: Biochemical freedom from disease for 920 men treated for prostate cancer with external beam radiation alone between March 1987 and December 1997 was compared according to hereditary/familial history (PFH) and sporadic family history. To adjust for known predictors of biochemical outcome, 97 PFH patients were randomly matched 2:1 to 194 sporadic patients according to age, grade, pretreatment prostate-specific antigen level, and palpation stage and compared in terms of biochemical outcome. Cox multivariate regression analyses were also performed to identify independent predictors of outcome in the two patient populations. RESULTS: In both patient populations, univariate analysis of biochemical outcome demonstrated no difference according to family history groupings. After adjusting for known predictors of biochemical outcome, multivariate analysis confirmed the nonsignificant univariate findings. CONCLUSIONS: No difference was found in this study between patients with a PFH (combined hereditary and familial) and patients with the sporadic form of prostate cancer. Recent published reports are conflicting and the question of whether a genetic change influencing prostate cancer causation is associated with factors altering treatment response should be addressed using a multi-institutional, carefully documented, prospective family history data collection and outcome analysis.     

Dyspnoea and exercise intolerance during cardiopulmonary exercise testing in patients with univentricular heart. The effects of chronic hypoxaemia and Fontan procedure

BACKGROUND: Patients with univentricular hearts have decreased exercise tolerance and may demonstrate exertional dyspnoea. It is not known if chronic hypoxaemia exacerbates exercise intolerance and contributes to symptomatic limitation. The extent to which surgical correction of a right-to-left shunt by a Fontan-type procedure can increase exercise tolerance by reducing arterial deoxygenation is not well documented. The cardiopulmonary exercise responses and the symptomatic status in two groups of univentricular patients, those who are cyanotic and those who are acyanotic with Fontan-type circulation, were compared. METHODS AND FINDINGS: Cardiopulmonary exercise testing was performed in 10 univentricular patients with rest or stress-induced cyanosis (age 30.5 +/- 2.3 [SE] years; 5 men) who had palliative or no surgery and eight patients (age 29.4 +/- 1.5 years; 4 men) with Fontan-type circulation. Peak oxygen consumption was comparable in both groups of univentricular patients (21.7 +/- 2.5 vs 21.0 +/- 1.9 ml.kg-1.min-1, P = 0.85) but was less than an age-matched group of 10 healthy subjects (34.7 +/- 1.9 ml.kg-1.min-1, P < 0.001 for both). Arterial oxygen saturation was 90.6% at rest in the cyanotic patients compared with 95.1% in the Fontan patients (P < 0.001) and at peak exercise, 66.2% compared with 90.5% (P < 0.001). Using a modified Borg scale (0-10), the symptoms of dyspnoea and fatigue were also assessed during exercise in the patient groups. The Borg scores for dyspnoea in the cyanotic and the corrected univentricular patients were, respectively, as follows: Stage 1: 0.5 vs 1.7; P= 0.04; Stage 2: 1.8 vs 2.3, P = 0.5; Stage 3: 3.0 vs 3.5, P = 0.7; Peak Exercise: 4.9 vs 4.8, P = 0.9. In addition, the Borg scores for fatigue were: Stage 1: 0.4 vs 1.6, P = 0.08; Stage 2: 2.0 vs 2.2, P = 0.9; Stage 3: 3.0 vs 4.3, P = 0.5; Peak Exercise: 4.9 vs 5.4, P = 0.5. The major limiting symptom at peak exercise was dyspnoea in four cyanotic patients compared with one in the Fontan group (Chi-square 0.982, P > 0.10). The arterial oxygen desaturation at peak exercise in the cyanotic patients limited by dyspnoea was not different from those limited by fatigue (67.5 +/- 10.1% vs 66.7 +/- 13.7%, P = 0.92). Exercise tolerance was also not related to the arterial oxygen saturation at peak exercise (r = 0.47, P = 0.17) in these patients. CONCLUSIONS: Despite correction with Fontan-type surgery, the exercise tolerance and symptoms of these univentricular patients remained similar to those who were cyanosed. Cyanotic patients have adjusted to chronic hypoxaemia and it does not appear to determine the exercise tolerance or the genesis of dyspnoea in these patients. Further randomized prospective studies are required to investigate the long-term benefits of Fontan-type procedures in these patients on exercise tolerance, symptoms and prognosis.     

Cardiopulmonary exercise testing in the evaluation of patients with occupational asthma and reactive airways dysfunction syndrome

Oxidative stress has been known to play important roles in various inflammatory diseases of lung such as allergic bronchitis, dust particle-induced inflammatory diseases, or chronic bronchitis. However, the effects of oxidants on Cl- secretion in tracheal epithelia have not been determined. To examine the effects of oxidants on Cl- secretion of the airway epithelia rat tracheal epithelial cells were cultured on porous filters and short circuit current (Isc) was measured in an Ussing chamber system. t-Butylhydroperoxide, which was widely used as a model substance to study the mechanism of cell injury resulted from oxidative stress, induced a transient increase in Isc by dose-dependent manner. The response was not observed in Cl(-)-free medium, and inhibited by 100 microM bumetanide. N(-Diphenyl-1,4-phenylene-diamine (DPPD, 5 microM), an inhibitor of lipid peroxidation, blocked the t-butylhydroperoxide response. When t-butylhydroperoxide was added after the administration of forskolin or H-89, a protein kinase A inhibitor, the t-butylhydroperoxide-induce Isc increase was abolished. Pretreatment of indomethacin (10 microM) completely inhibited the t-butylhydroperoxide response, but pretreatment of thapsigargin (1 microM) did not, t-Butylhydroperoxide induced gradual increases in cytosolic Ca2+ level, and increased [3H]arachidonic acid release in the presence of thapsigargin. These results indicate that t-butylhydroperoxide stimulates Cl-secretion via activation of phospholipase A2 and subsequent production of cyclooxygenase metabolities by Ca(2+)-dependent and -independent mechanisms.     

Recurrent unexplained syncope: the role of head-upright tilt table testing

Recurrent episodes of sudden unexplained syncope are a common complaint of patients referred to health care professionals for evaluation. Traditional evaluations are both time consuming and expensive and leave many patients without a diagnosis. Although vasovagally mediated episodes of hypotension and bradycardia have been thought to be a common cause of unexplained syncope, this was traditionally a diagnosis of exclusion. Head-upright tilt table testing has recently emerged as a valuable method for confirming the diagnosis of vasovagal syncope and has allowed a better understanding of this phenomena. This article reviews the pathophysiology of vasovagal syncope, the use of head-upright tilt table testing in its diagnosis, and potential therapies used to prevent recurrences.     

Supervised exercise training improves cardiopulmonary fitness in HIV-infected persons

We attempted to measure cardiopulmonary effects, CD4 counts, and perceived sense of well-being in 25 individuals moderately to severely immunocompromised from HIV infection (mean entry CD4 count = 144.microliters-1) before and after a 24-wk program of exercise training. Only six subjects completed the 24-wk program. All six showed evidence of a training effect. Statistically significant improvements were seen in maximal oxygen consumption (VO2max), oxygen pulse, and minute ventilation. Submaximal exercise performance improved significantly by 12 wk in the 10 individuals available for testing: decreases were seen in heart rate, rate pressure product, and rate of perceived exertion. White blood cell counts and T-lymphocyte subsets were stable at 12 and 24 wk in the subjects available for testing. High depression/anxiety scores on a mental health inventory (General Health Questionnaire) correlated with low CD4 counts. Scores did not correlate with compliance with the exercise program. There was a trend (P < 0.10) for scores to improve over time among those individuals who attended > or = 80% of scheduled exercise sessions. We conclude that exercise training is feasible and beneficial for some HIV-infected individuals.     

Interpretive algorithms for the symptom-limited exercise test: assessing dyspnea in Persian Gulf war veterans

The mechanisms by which respiratory syncytial virus (RSV) infection induces bronchiolitis and airway disease are unclear. The presence of large numbers of polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection suggests a potential role of PMN in airway injury associated with RSV infection. To investigate the potential role of neutrophils in RSV bronchiolitis, human alveolar type II cells (A549 cells) were infected with different doses of RSV for 6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image analysis was used to determine PMN adhesion and detachment of epithelial cells. The results showed that RSV infection of epithelial cells enhanced PMN adherence in a dose- and time-dependent pattern, RSV infection alone could damage and detach epithelial cells to a limited extent and PMN significantly augmented RSV infection-induced damage and detachment of epithelial cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances neutrophil adhesion to the epithelium and that activated neutrophils augment the damage and detachment of epithelium infected with the virus. Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory syncytial virus airway disease by inducing epithelial damage and cell loss.     

Value of exercise treadmill testing in women

OBJECTIVES: We sought to determine the ability of a treadmill score to provide accurate diagnostic and prognostic risk estimates in women. BACKGROUND: Treadmill testing has been reported to have a lower accuracy for diagnosis of chest pain in women. The diagnostic and prognostic value of the Duke Treadmill Score (DTS) in women is unknown. METHODS: We determined the diagnostic and prognostic value of the DTS in 976 women and 2,249 men who underwent both treadmill testing and cardiac catheterization in a single institution from 1984 to 1994. RESULTS: Women and men differed significantly in DTS (1.6 vs. -0.3, p < 0.0001), disease prevalence (32% vs. 72% significant coronary artery disease [CAD], p < 0.001), and 2-year mortality (1.9% vs. 4.9%, p < 0.0001). The DTS provided information beyond clinical predictors of both coronary disease and survival in women and men. Although overall women had better survival, the DTS performed equally well in stratifying both genders into prognostic categories. The DTS actually performed better in women than in men for excluding disease, with fewer low risk women having any significant coronary disease (> or = 1 vessel with > or =75% stenosis) (20% vs. 47%, p < 0.001), or severe disease (3-vessel disease or > or =75% left main stenosis) (3.5% vs. 11.4%, p < 0.001). CONCLUSIONS: By combining several aspects of treadmill testing, the DTS effectively stratifies women into diagnostic and prognostic risk categories.     

模糊综合评判在学校评估中的应用

学校整体管理工作受多种因素的影响 ,文章将评估中所涉及的因素看作模糊因素 ,应用模糊数学的综合评估方法建立了学校整体办学水平综合评估体系 .     

Constrictive pericarditis after coronary artery bypass surgery as a cause of unexplained dyspnea: a report of five cases

Constrictive pericarditis after coronary artery bypass grafting (CABG) is rare and can present as unexplained dyspnea. We report five consecutive cases of post-CABG constrictive pericarditis seen within a period of 17 months at our institution. All patients presented with heart failure of unknown etiology within a period of 8-84 months after surgery. During the initial post-CABG period, two patients had developed postcardiotomy syndrome that was successfully treated with steroids. They were all assessed noninvasively and invasively. In all patients, the diagnosis of constriction was initially suspected clinically (symptoms, high jugular venous pressure with deep "X" and "Y" descents, pericardial knock). Echocardiography showed transmitral flow typical of constriction in all patients and hepatic venous flow in two. Two patients showed rapid left ventricular relaxation. In all patients, hemodynamic assessment showed diastolic equalization of pressures in all chambers, "W" shape waveform in right atrial pressure, and "dip and plateau" configuration in right and left ventricular pressure waveforms. Diagnosis was confirmed surgically in four patients who were subjected to pericardiectomy-pericardial stripping (three survived, one died). One patient refused surgery. We conclude that constrictive pericarditis, although rare, should be suspected in every case of unexplained dyspnea post CABG. It can appear early or late after surgery, and clinical examination plays an important role in its early recognition. It requires a full noninvasive and invasive assessment in case of clinical suspicion.     

Cardiovascular responses to treadmill exercise testing in anemia

Gunshot wounds are rare in Japan because of few regulatory laws against the possession of guns. Nevertheless such wounds are increasing in prevalence these days. Reports on the microscopic findings concerning these intracerebral lesions are fewer than those on the macroscopic findings in the scalp, the skull and the intracranial cavity. In this study we evaluated computed tomographical and histopathological findings in craniocerebral gunshot injuries. CASES: Nine patients with gunshot wounds to the head were presented. All were male and the age ranged from 17 to 66 years. Four were suicides and four were attempted murders and the last one was of unknown etiology. Morphological examination was performed on 5 autopsy cases. The distance of the bullet from the cranial cavity was as follows: long distance, 4 cases; close contiguity, 5 cases. The calibers of the weapons were as follows: 38 mm in 6 cases, 45 mm in 1 case and unknown in 2 cases. RESULTS: CT scans were examined in six cases, which revealed a missile track, hemorrhagic contusion, traumatic subarachnoid hemorrhage and marked tension pneumocephalus. In some cases, CT scan also revealed bony and metallic fragments, some deep within the cranial cavity. In the histopathological study, we found marked swollen brain (brain weight over 1500 mg) and hemorrhagic contusion in the vicinity of the missile track and interhemispheric fissure, and widespread traumatic subarachnoid hemorrhage and intraventricular hematoma. We would like to emphasize especially the remote contusion seen in the distant part of the missile track as well as massive exsudation and hemorrhage around the nerve fiber bundles. Remote contusion was observed in the inferior surface of the fronto-temporal lobes, and bilateral hemorrhagic contusion was seen in the vicinity of the superior longitudinal fissure on CT scans and autopsy findings. In one case, the bullet rotated within the intracranial cavity. In conclusion, nine cases of craniocerebral gunshot injuries were examined, while we also reviewed the medical literature concerning the shearing injury produced by gunshot brain wounds. The head injuries were further delineated by the correlation between autopsy and computerized tomography findings.     

Does cold air affect exercise capacity and dyspnea in stable chronic obstructive pulmonary disease?

Cold air may worsen asthmatic bronchoconstriction but can lessen breathlessness in normal individuals. Patients with COPD sometimes report improvement in their dyspnea in cold weather. We examined the effect of breathing cold air on exercise tolerance and the perception of breathlessness in 19 patients with stable COPD (age [+/- SD], 63 +/- 6 years; FEV1, 0.99 +/- 0.28 L) in a randomized open study. Patients exercised on a cycle ergometer breathing either room or cold air (-13 degrees C), breathlessness being assessed by Borg scaling. Peak exercise performance improved when breathing cold air (mean +/- SE), 46 +/- 6 W compared with 37 +/- 7 W (p < 0.05) while end-exercise breathlessness fell from 4.6 +/- 0.4 compared with 4.1 +/- 0.5 (p < 0.05) when breathing cold air. End-exercise ETCO2 was higher breathing cold air (6.1 +/- 0.3 kPa compared with 5.5 +/- 0.3 kPa) (p < 0.005). There was no difference in breathlessness at equivalent levels of ventilation. Cold air reduces breathlessness in COPD, probably by inducing relative hypoventilation.     

Special considerations in exercise testing. Protocols, equipment, and testing athletes

A growing number of physicians are performing exercise tests in their offices for the purposes of diagnosing cardiopulmonary disease and assessing exercise capacity in patients with heart disease. Methodology of testing is important in making the most effective use of the information gathered from the test. Selecting an approach that fits the objectives of the test and the individual being tested is essential for accurate and reproducible results. This article discusses the various exercise protocols and equipment used in exercise testing.     

Predicting severe ischemic events after uncomplicated myocardial infarction by exercise testing and rest and exercise radionuclide ventriculography

BACKGROUND: In 183 patients with uncomplicated myocardial infarction, exercise-induced angina, ST segment depression, decrease in ejection fraction, or inadequate increase in systolic blood pressure and low exercise tolerance were significantly associated with 4-year incidence of hard ischemic events. METHODS AND RESULTS: Only the onset of both ST segment depression and a decrease in left ventricular ejection fraction with exercise was an independent predictor. ST segment depression and decrease in left ventricular ejection fraction had low sensitivity (61% and 70%) and specificity (56% and 51%) for hard ischemic events, but specificity increased to 78% when both were present. During medical therapy, 22 of 53 patients with both ST segment depression and a decrease in left ventricular ejection fraction with exercise had an ischemic event (i.e., 48.1% 4-year probability on Kaplan-Meier analysis vs 19.2% in the remaining 130 patients [p < 0.0005]). CONCLUSIONS: Even if no single variable, derived from exercise testing, is a highly sensitive and specific predictor, specificity increases to a clinically relevant level by combining ST segment depression and a decrease in left ventricular ejection fraction with exercise, and in this way patients with recent infarction may be selected for coronary arteriography.