Loss of endothelium mediated vascular relaxation as a response to various clamping pressures. Part II. Direct measurements of clamping pressures and scanning electron microscope study

BACKGROUND: Accurate prognosis in chronic heart failure has become increasingly important in assessing the efficacy of treatment and in appropriately allocating scarce resources for transplantation. Previous studies of severe heart failure have been limited by short follow-up periods and few deaths. OBJECTIVE: To establish clinical, hemodynamic, and cardiopulmonary exercise test determinants of survival in patients with heart failure. DESIGN: Retrospective study. SETTING: Hospital-based outpatient heart failure clinic. PARTICIPANTS: 644 patients referred for evaluation of heart failure over 10 years. MEASUREMENTS: Age, cause of heart failure, body surface area, cardiac index, ejection fraction, pulmonary capillary wedge pressure, left ventricular dimensions, watts achieved during exercise, heart rate, maximum systolic blood pressure, and oxygen uptake (VO2) at the ventilatory threshold and at peak exercise were measured at baseline. Univariate and multivariate analyses were done for clinical, hemodynamic, and exercise test predictors of death. A Cox hazards model was developed for time of death. RESULTS: During a mean follow-up period of 4 years, 187 patients (29%) died and 101 underwent transplantation. Actuarial 1-year and 5-year survival rates were 90.5% and 73.4%, respectively. Resting systolic blood pressure, watts achieved, peak VO2, VO2 at the ventilatory threshold, and peak heart rate were greater among survivors than among nonsurvivors. Cause of heart failure (coronary artery disease or cardiomyopathy) was a strong determinant of death (relative risk for coronary artery disease, 1.73; P< 0.01). By multivariate analysis, only peak VO2 was a significant predictor of death. Stratification of peak VO2 above and below 12, 14, and 16 mL/kg per minute demonstrated significant differences in risk for death, but each cut-point predicted risk to a similar degree. CONCLUSIONS: Peak VO2 outperforms clinical variables, right-heart catheterization data, exercise time, and other exercise test variables in predicting outcome in severe chronic heart failure. Direct measurement of VO2 should be included when clinical or surgical decisions are being made in patients referred for evaluation of heart failure or those considered for transplantation.     

Prevention of respiratory complications after abdominal surgery

Abdominal surgery, especially upper abdominal surgical procedures are known to adversely affect pulmonary function. Pulmonary complications are the most frequent cause of postoperative morbidity and mortality. This review article aimed to analyse the incidence and risk factors for postoperative pulmonary morbidity and their prevention. The most important means for preoperative assessment is the clinical examination; pulmonary function tests (spirometry) are not reliably predictive for postoperative pulmonary complications. Age, type of surgical procedure, smoking and nutritional state have all been identified as potential predictors for postoperative complications. However, usually there is not enough preoperative time available to obtain beneficial effects of stopping smoking and improvement of nutritional state. In patients with COPD, a preoperative multidisciplinary evaluation including the primary care physician, pulmonologist/intensivist, anesthesiologist and surgeon is required. Consensus as to preoperative physiologic state, therapeutic preparation, and postoperative management is essential. Simple spirometry and arterial blood gas analysis are indicated in patients exhibiting symptoms of obstructive airway disease. There are no values that contra-indicate an essential surgical procedure. Smoking should stop at least 8 weeks preoperatively. Preoperative therapy for elective surgery with antibiotics, beta2-agonist, or anticholinergic bronchodilator aerosols, as well as training in cough and lung expansion techniques should begin at least 24 to 48 hours preoperatively. Postoperative therapy should be continued for 3 to 5 days. Usually, anaesthesia is responsible for early complications, whereas surgical procedures are often associated with delayed morbidity. Laparoscopic procedures are recommended, as postoperative morbidity and hospital stay seem reduced in patients without COPD. Regional anaesthesia is given as having less adverse effects on pulmonary function than general anaesthesia. However, for unknown reasons these benefits are not associated with a decrease in postoperative respiratory complications. Moreover, the quality or the type of postoperative analgesia does not influence postoperative respiratory morbidity. Postoperatively, oxygen administration increases SaO2, but cannot abolish desaturation due to obstructive apnea. The various techniques of physiotherapy (chest physiotherapy, incentive spirometry, continuous positive airway pressure breathing) seem to be equivalent in efficacy; but intermittent positive pressure breathing has no advantages, compared with the other treatments and could even be deleterious. Chest physiotherapy and incentive spirometry are the most practical methods available for decreasing secretion contents of airways, whereas continuous positive airway pressure breathing is efficient on atelectasis. In stage II or III COPD patients, admission in a intensive therapy unit and prolonged mechanical ventilation may be required.     

Is peak VO2 a maximal index of children's aerobic fitness?

A levelling of oxygen uptake (VO2 plateau) at high exercise intensities is conventionally used as the criterion for establishing VO2max during progressive, incremental exercise testing. Only a minority of children, however, demonstrate a VO2 plateau during exercise to voluntary exhaustion. This study was therefore designed to investigate whether a VO2 plateau is required before peak VO2 can be considered a maximal index of children's aerobic fitness. Eighteen girls and 17 boys (age 9.9 +/- 0.4 yrs) carried out three treadmill tests to exhaustion one week apart. The first test comprised a discontinuous, incremental protocol to voluntary exhaustion. In test two each child warmed up and then ran to exhaustion at the same belt speed but on a gradient 2.5% greater than that which had produced an exhaustive effort on the first test. The third test was conducted similarly but the treadmill gradient was raised to 5% greater than that which had produced an exhaustive effort on the first test. Seven girls and 6 boys demonstrated a VO2 plateau (< or = 2 ml.kg-1.min-7) on the first test but no significant differences in either anthropometrical or peak physiological data were detected between those who demonstrated a plateau and those who did not. Mean peak VO2 values during tests two and three (supramaximal tests) did not increase significantly above that achieved on test one although indicators of an increased anaerobic contribution were significantly higher in both supramaximal tests. These findings indicate that peak VO2 in test one was a maximal value despite the absence of a VO2 plateau. The requirement of a VO2 plateau before peak VO2 can be regarded as a maximal index of young children's aerobic fitness is therefore untenable.     

Kinetics of the homogeneous exchange of alpha-lactalbumin adsorbed on titanium oxide surface

BACKGROUND: We prospectively evaluated the potential of the 6-minute walk test compared with peak VO2 in predicting outcome of patients with New York Heart Association (NYHA) class II or III heart failure. METHODS AND RESULTS: Patients with a history of heart failure caused by systolic dysfunction were included. The combined final outcome (death or hospitalization for heart failure) was used as the judgment criterion. One hundred twenty-one patients (age 59+/-11 years; left ventricular ejection fraction 29.6%+/-13%) were included and followed for 1.53+/-0.98 years. Patients were separated into two groups according to outcome: group 1 (G1, 74 patients), without events, and group 2 (G2, 47 patients), who reached the combined end point. Peak VO2 was clearly different between G1 and G2 (18.5+/-4 vs. 13.9+/-4 ml/kg/min, p=0.0001) but not the distance walked (448+/-92 vs 410+/-126 m; p=0.084, not significant). Survival analysis showed that unlike peak VO2, the distance covered was barely distinguishable between the groups (p < 0.08). However, receiver operating characteristic curves revealed that the best performances for the 6-minute walk test were obtained for subjects walking < or =300 m. These patients had a worse prognosis than those walking farther (p=0.013). In this subset of patients, there was a significant correlation between distance covered and peak VO2 (r=0.65, p=0.011). Thus it appears that the more severely affected patients have a daily activity level relatively close to their maximal exercise capacity. Nevertheless, the 300 m threshold suggested by this study needs to be validated in an independent population. CONCLUSIONS: A distance walked in 6 minutes < or =300 m can predict outcome. Moreover, in these cases there is a significant correlation between the 6-minute walk test and peak VO2 demonstrating the potential of this simple procedure as a first-line screening test for this subset of patients.     

Control of early cardiac-specific transcription of Nkx2-5 by a GATA-dependent enhancer

STUDY OBJECTIVE: To determine the impact of preoperative resting hypercapnia on patient outcome after bilateral lung volume reduction surgery (LVRS). METHODS: We prospectively examined morbidity, mortality, quality of life (QOL), and physiologic outcome, including spirometry, gas exchange, and exercise performance in 15 patients with severe emphysema and a resting PaCO2 of > 45 mm Hg (group 1), and compared the results with those from 31 patients with a PaCO2 of < 45 mm Hg (group 2). RESULTS: All preoperative physiologic and QOL indices were more impaired in the hypercapnic patients than in the eucapnic patients. The hypercapnic patients exhibited a lower preoperative FEV1, a lower diffusing capacity of the lung for carbon monoxide, a lower ratio of PaO2 to the fraction of inspired oxygen, a lower 6-min walk distance, and higher oxygen requirements. However, after surgery both groups exhibited improvements in FVC (group 1, p < 0.01; group 2, p < 0.001), FEV1 (group 1, p=0.04; group 2, p < 0.001), total lung capacity (TLC; group 1, p=0.02; group 2, p < 0.001), residual volume (RV; group 1, p=0.002; group 2, p < 0.001), RV/TLC ratio (group 1, p=0.03; group 2, p < 0.001), PaCO2 (group 1, p=0.002; group 2, p=0.02), 6-min walk distance (group 1, p=0.005; group 2, p < 0.001), oxygen consumption at peak exercise (group 1, p=0.02; group 2, p=0.02), total exercise time (group 1, p=0.02; group 2, p=0.02), and the perceived overall QOL scores (group 1, p=0.001; group 2, p < 0.001). However, because the magnitude of improvement was similar in both groups, and the hypercapnic group was more impaired, the spirometry, lung volumes, and 6-min walk distance remained significantly lower post-LVRS in the hypercapnic patients. There was no difference in mortality between the groups (p=0.9). CONCLUSIONS: Patients with moderate to severe resting hypercapnia exhibit significant improvements in spirometry, gas exchange, perceived QOL, and exercise performance after bilateral LVRS. The maximal achievable improvements in postoperative lung function are related to preoperative level of function; however, the magnitude of improvement can be expected to be similar to patients with lower resting PaCO2 levels. Patients should not be excluded from LVRS based solely on the presence of resting hypercapnia. The long-term benefit of LVRS in hypercapnic patient remains to be determined.     

Prognostic value of exercise gamma-angiography in coronary insufficiency

The predictive value for cardiac events in stable coronary artery disease was analysed with resting and exercise radionuclide angiography and conventional exercise stress testing under medical therapy. The population comprised 93 men and 12 women, followed up for 1 to 8 years (mean 51 months). The patients were divided into two groups. Group I without cardiac events; Group II including spontaneous complications and myocardial revascularisations. The analysis was performed at 2 years and at the end of follow-up. At 2 years, 30 events (15 spontaneous complications, 15 revascularisations) were observed, and at the end of follow-up, there were 61 uncomplicated outcomes and 44 cardiac events (22 spontaneous complications, 22 revascularisations). Two independent prognostic factors distinguishing patients in Group I from those in Group II were identified at 2 years and at the end of the study: exercise EF and occurrence of exercise (on: chest pain on exercise) chest pain. Four parameters were significantly different between the two groups at 2 years: exercise EF, resting EF, difference between exercise-resting EF (all p < 0.005) and duration of exercise testing (p = 0.04). The 3 radionuclide parameters remained different between the 2 groups as well as chest pain on exercise stress testing (p = 0.03) throughout the study. The predictive value of these parameters depended on the type of cardiac event. The exercise EF was the best predictive factor of cardiac death. Pain and ST depression on exercise ECG were the best predictive factors for myocardial revascularisation. In 12 patients undergoing myocardial revascularisation, the clearest improvement was observed in exercise EF (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Outpatient echocardiography as a predictor of perioperative cardiac morbidity after peripheral vascular surgical procedures

PURPOSE: A variety of preoperative provocative tests have been used to define the risk of cardiac morbidity and mortality after peripheral vascular procedures, including dipyridamole myocardial scintigraphy and dobutamine stress echocardiography. Although highly sensitive, these tests are time-consuming and associated with significant expense. We investigated outpatient echocardiography as a less resource-intensive means of assessing cardiac risk with operation. METHODS: Over a 2-year period 250 consecutive patients underwent outpatient transthoracic echocardiography before elective peripheral vascular operation was performed. The accuracy of the Goldman, Detsky, and the American Society of Anesthesiologists' Physical Status Classification clinical indexes of cardiac risk were assessed with regard to the development of cardiac complications such as unstable angina, myocardial infarction, life-threatening ventricular arrhythmias, severe congestive heart failure, and cardiogenic shock. The accuracy of echocardiographically determined left ventricular ejection fraction was determined at threshold values between 20% and 60%. RESULTS: Perioperative cardiac events developed in 23 (9.2%) of the patients, and nine (3.6%) of the patients died as a result of these complications. Clinical indexes lacked sensitivity in the preoperative prediction of cardiac complications. Receiver operating curve analysis defined a left ventricular ejection fraction of less than 50% as an appropriate threshold for defining patients at high risk, with a sensitivity of 78% and a specificity of 81% in the identification of patients who had cardiac morbidity. The positive predictive value was 27%, and the negative predictive value was 97%. The economic impact of outpatient echocardiography was well below that of dipyridamole myocardial scintigraphy or dobutamine stress echocardiography. CONCLUSIONS: Outpatient echocardiography appears to offer a cost-efficient compromise between clinical criteria alone and provocative cardiac testing such as dipyridamole myocardial scintigraphy and dobutamine stress echocardiography in the preoperative screening of patients undergoing peripheral vascular surgical procedures.     

Differences in duration of Huntington's disease based on age at onset

OBJECTIVE: The accurate determination of limitations in physical activity is important in evaluating patients with heart failure and in assessing the efficacy of treatment. However, the conventional measures used to evaluate hemodynamics, functional class, and exercise capacity all have limitations. Our objective was to develop a simple method (The Master-Borg test) for evaluating the physical activity of patients with chronic heart failure using self-evaluation of the sensation of dyspnea at a constant workload. METHODS: Patients with NYHA class I (N = 20), class II (N = 20), and class III (N = 20) chronic heart failure performed a symptom-limited treadmill exercise test to determine peak VO2 and anaerobic threshold (AT). Patients subsequently performed Master's two-step test for 90 s and maximal dyspnea was self-rated using the visual analog Borg scale (the Master-Borg test). RESULTS: The mean workload in the Master-Borg test was 15.2+/-1.6 mL x min(-1) x kg(-1). A significant correlation was found between the Master-Borg score and peak VO2 (r = 0.87) or AT (r = 0.84). The reproducibility of the Master-Borg tests was represented by a correlation coefficient of 0.93. CONCLUSION: Although simple and inexpensive, the Master-Borg test accurately represents ordinary activity levels, relates the sensation of dyspnea to peak exercise tolerance, and can be completed by most patients with heart failure. Master-Borg scores correlated with peak VO2 and AT, and can differentiate among NYHA classes I, II, and III. The Master-Borg test appears to be clinically useful for evaluating the value of physical activity and exercise capacity of patients with chronic heart failure.     

Microvascular permeability of the non-heart-beating rabbit lung after warm ischemia and reperfusion: role of neutrophil elastase

STUDY OBJECTIVES: Criteria used to define the respective roles of pulmonary mechanics and cardiovascular disease in limiting exercise performance are usually obtained at peak exercise, but are dependent on maximal patient effort. To differentiate heart from lung disease during a less effort-dependent domain of exercise, the predictive value of the breathing reserve index (BRI=minute ventilation [VE]/maximal voluntary ventilation [MVV]) at the lactate threshold (LT) was evaluated. DESIGN: Thirty-two patients with COPD and a pulmonary mechanical limit (PML) to exercise defined by classic criteria at maximum oxygen uptake (VO2max) were compared with 29 patients with a cardiovascular limit (CVL) and 12 normal control subjects. Expired gases and VE were measured breath by breath using a commercially available metabolic cart (Model 2001; MedGraphics Corp; St. Paul, Minn). Arterial blood gases, pH, and lactate were sampled each minute during exercise, and cardiac output (Q) was measured by first-pass radionuclide ventriculography (System 77; Baird Corp; Bedford, Mass) at rest and peak exercise. RESULTS: For all patients, the BRI at lactate threshold (BRILT) correlated with the BRI at VO2max (BRIMAX) (r=0.85, p<0.0001). The BRILT was higher for PML (0.73+/-0.03, mean+/-SEM) vs CVL (0.27+/-0.02, p<0.0001), and vs control subjects (0.24+/-0.03, p<0.0001). A BRILT > or = 0.42 predicted a PML at maximum exercise, with a sensitivity of 96.9%, a specificity of 95.1%, a positive predictive value of 93.9%, and a negative predictive value of 97.5%. CONCLUSIONS: The BRILT, a variable measured during the submaximal realm of exercise, can distinguish a PML from CVL.     

Paclitaxel is preferentially cytotoxic to human cervical tumor cells with low Raf-1 kinase activity: implications for paclitaxel-based chemoradiation regimens

Little is known about the association of echocardiographic estimates of right ventricular (RV) function with survival, in relation to hemodynamic and exercise-derived predictors of outcome in congestive heart failure. We prospectively studied 40 patients (age 55+/-10 years, in New York Heart Association functional class III [70%] and IV [30%]), with left ventricular (LV) ejection fraction <30%. At enrollment, all patients underwent echocardiographic evaluation of LV dimensions and function. RV shortening was measured as the difference of the end-diastolic distance - the end-systolic distance between the tricuspid annulus and the RV apex. Thirty-five patients (88%) were able to perform a maximal symptom-limited exercise test. Peak oxygen consumption (peak VO2) and percent peak age- and gender-adjusted predicted oxygen consumption (%peak VO2) were calculated. Of 40 patients, 10 died during a mean follow-up period of 14+/-10 months. On univariate analysis, nonsurvivors had lower RV shortening (p=0.0001), higher pulmonary artery wedge pressure (p=0.009), higher pulmonary vascular resistance (p=0.02), and lower mean aortic pressure (p=0.05). Cox proportional-hazards model revealed that the only independent associate of survival was RV shortening (p=0.0005), with a trend toward significance for mean aortic pressure (p=0.08). The best cutoff point of RV shortening identified by the receiver-operating curve was 1.25 cm. This value had a sensitivity of 90%, specificity of 80%, and overall predictive accuracy of 83% to distinguish survivors from nonsurvivors. In patients with advanced heart failure, preserved RV function as indicated by an echocardiographically derived RV shortening > 1.25 cm is a strong predictor of survival.     

Prediction of exercise capacity after lung resection in patients with chronic airflow limitation

To assess the usefulness of a method for predicting postoperative peak oxygen uptake based on lost lung function after lung resection (VO2peak-PPO) and to establish the underlying physiological foundation for the relation between VO2peak-PPO and the measured postoperative value VO2peak-PO), we studied 29 patients (26 men) [age 60 (SD9)] with chronic airflow limitation [FEV1 = 66 (SD13)%] undergoing lobectomy or major pulmonary resection to treat lung cancer. The patients were assigned to groups according to whether postoperative exercise tolerance was considered to be limited by exhaustion of ventilatory reserve (LV) or not (NLV). Data to estimate postoperative pulmonary function was obtained one week before surgery: patients performed pulmonary function tests and exercise tests on a treadmill; dyspnea was also evaluated and perfusion scintigraphs were obtained. Pulmonary function, exercise tolerance and dyspnea were evaluated again approximately five months after surgery. The mean difference between VO2peak-PPO and VO2peak-PO was -0.034 (CI 0.293 to -0.348) l.min-1 and the between-group correlation coefficient was 0.76. The correlation between VO2peak-PPO and VO2peak-PO was 0.86 (SE 0.1) [0.89 (SE 0.13) for LV (n = 14) patients and 0.85 (SE 0.16) for NLV (n = 15) patients]. The correlations after adjusting for preoperative VO2peak-PPO were 0.73 (SE 0.2) and 0.35 (SE 0.27) for LV and NLV patients, respectively. We conclude that VO2peak-PPO provides a valid but only moderately precise estimate of VO2peak-PO. Only in LV patients is there a true relation between a decrease in VO2peak and loss of lung function.     

Low incidence of myocardial recovery after left ventricular assist device implantation in patients with chronic heart failure

BACKGROUND: Mechanical, histological, and biochemical improvement has been described in patients after left ventricular assist device (LVAD) support. Explantation of the LVADs without heart transplantation has been described in selected patients who received this therapy as a bridge to transplantation. METHODS AND RESULTS: A retrospective review of patients receiving a mechanical bridge to transplantation at Columbia Presbyterian Hospital after July 21, 1991, was performed to determine the incidence of patients in whom the device was successfully explanted. From August 1, 1996, to February 1, 1998, we prospectively attempted to identify potential explant candidates by the use of exercise testing. During this time, we recruited 39 consecutive patients after insertion of the Thermo Cardiosystems vented electric device to participate in the following study. Approximately 3 months after device implantation, a maximal exercise test with hemodynamic monitoring and respiratory gas analysis was performed with the LVAD in the automated mode. The electric device was interfaced with a pneumatic console such that the rate could be decreased to 20 cycles/min. Hemodynamic measurements were recorded as the device rate was decreased. A repeat exercise test was then performed if the patient remained hemodynamically stable. A retrospective chart review of 111 LVAD recipients at our institution identified only 5 successful explant patients. Eighteen of the 39 patients were studied. Fifteen patients exercised with maximal device support. At peak exercise, VO2 averaged 14.5+/-3.6 mL. kg-1. min-1; LVAD flow, 8.0+/-1.3 L/min; Fick cardiac output, 11.4+/-3.3 L/min; and pulmonary capillary wedge pressure, 13+/-4 mm Hg. Seven patients remained normotensive and could exercise at a fixed rate of 20 cycles/min. In these patients, peak VO2 declined from 17.3+/-3.9 to 13.0+/-6.1 mL. kg-1. min-1. In one of these patients, the device was explanted. CONCLUSIONS: Significant myocardial recovery after LVAD therapy in patients with end-stage congestive heart failure occurs in a small percentage of patients. Most of these patients have dilated cardiomyopathy. Exercise testing may be a useful modality to identify those patients in whom the device can be explanted.     

Role of kinins in basal and furosemide-stimulated renin secretion

OBJECTIVE: To determine risk factors predictive of outcomes to aid in the cost-effective preoperative evaluation and postoperative management of patients who are undergoing tonsillectomy and adenoidectomy for obstructed breathing during sleep. DESIGN: A historical cohort study with a nested case-control analysis that examined risk factors associated with postoperative respiratory complications. SETTING: Children's Medical Center of Dallas, Dallas, Tex, which is a pediatric referral hospital for secondary and tertiary pediatric care with both private and university-appointed physicians. PATIENTS: A convenience sample of 355 patients who were undergoing tonsillectomy and adenoidectomy for obstructed breathing during sleep throughout a 1-year period. INTERVENTION: None. MAIN OUTCOME MEASURE: The occurrence of postoperative complications, including airway obstruction, apneas with oxygen desaturations, airway interventions (e.g., endotracheal intubation), or administration of supplemental oxygen, as they related to associated medical conditions (e.g., cerebral palsy or prematurity) and diagnostic tests (e.g., chest x-ray film and electrocardiogram). RESULTS: Five associated medical conditions (cerebral palsy; seizures; age, < or = 3 years; congenital heart disease; and prematurity) were identified as important predictors of a complicated postoperative course using stepwise logistic regression analysis. Those children with an abnormal chest x-ray film or electrocardiogram were also identified as having an associated medical condition that was predictive of postoperative complications. CONCLUSIONS: Children with 1 or more of the associated risk factors identified should be considered candidates for postoperative inpatient observation. A preoperative chest x-ray film and electrocardiogram were found to be of little predictive value, and they are probably not cost-effective screening tests for postoperative respiratory complications.     

Is the exercise test performed after myocardial infarct really useful in improving prognosis? Arguments in favor

The evaluation of risk after myocardial infarction accomplishes two objectives: a) selecting patients with high-risk for coronary angiography and revascularization, and b) identifying low-risk patients to avoid unnecessary laboratory investigation and revascularization procedures. Currently, patients eligible for exercise test are those with no evidence of heart failure or angina, and with a preserved left ventricular function. Overall prognosis for such patients, especially if they were thrombolyzed, is very good. In this setting, in contrast to that pointed out in previous reports, the positive predictive value of exercise electrocardiography is very low (i.e., a patient with S-T depression has a probability of cardiac death in the ensuing year of only 4% vs 2% if the test is negative). This suggests that a routine postinfarction exercise test is inefficient from a prognostic point of view. However, a recent study has shown that thrombolyzed patients with a positive response to the exercise test, have a significantly lower rate of reinfarction and unstable angina when they undergo myocardial revascularization. Mortality rate, as it was low in the study population, was unchanged by the use of revascularization procedures. We conclude that, in spite of the limitations pointed out, there are at least two reasons to continue performing exercise tests in all uncomplicated infarctions: a) a negative test, due to its high negative predictive value for adverse events, reassures the patient and his family and prompts an early discharge, and b) some patients, despite an uncomplicated in-hospital evolution, have a "strong" positive response that suggests multivessel disease and a possible benefit from myocardial revascularization.     

Prognostic value of myocardial hypoperfusion indexes in patients with suspected or known coronary artery disease

BACKGROUND: We evaluated the prognostic value of exercise 201Tl indexes of myocardial hypoperfusion in patients with suspected or known coronary artery disease. METHODS AND RESULTS: Patients were divided into two groups: group I consisted of 332 patients with diagnostic electrocardiographic stress test results and group II consisted of 144 patients with nondiagnostic (inadequate or uninterpretable) stress electrocardiograms. At the 2-year follow-up, 20 hard events (16 cardiac deaths and 4 nonfatal myocardial infarctions) and 80 soft events (coronary revascularization procedures) occurred in group I. Considering total events, thallium imaging provided significant prognostic information in addition to clinical and exercise stress test data in the total study population (p < 0.001) and in patients with previous myocardial infarction (p < 0.001); in patients without previous infarction, thallium imaging added incremental prognostic value only in those with positive electrocardiographic stress test results (p < 0.01). When only hard events were considered, thallium variables added further information only in patients with previous myocardial infarction (p < 0.05). In group II at the end of follow-up, 15 hard and 39 soft events had occurred. In these patients occurrence of total (p < 0.001), hard (p < 0.05), and soft (p < 0.001) events was higher in those with abnormal thallium scintigraphic results than in those without. Moreover, no clinical and exercise variable, except history of myocardial infarction, was significantly related to outcome, whereas both indexes of extent and severity of hypoperfusion were significant. CONCLUSIONS: The results of this study demonstrate that scintigraphic indexes of myocardial hypoperfusion obtained by qualitative planar thallium imaging give unique prognostic information in patients with nondiagnostic electrocardiographic stress test results. Thallium imaging provides incremental prognostic information even in patients with diagnostic electrocardiographic stress test results but not in the low-risk subset of patients without previous infarction who have negative electrocardiographic stress test results.     

Surgical therapy for hepatocellular carcinoma with liver cirrhosis

Approximately 80% of hepatocellular carcinoma (HCC) patients in Japan have associated liver cirrhosis, which increases the difficulty of surgical treatment. Liver dysfunction associated with liver cirrhosis is one of the most important predictive prognostic factors for HCC patients. Percutaneous ethanol injection therapy (PEIT) is useful for patients with small HCC or with poor hepatic functional reserve. Transcatheter arterial chemoembolization (TACE) is also useful both for patients with unresectable HCC and patients with multiple intrahepatic recurrence. Liver resection, however, lead to better outcome than other treatments when liver function is maintained after surgery. To determine operative procedures, it is important to evaluate the exact function of remnant liver, based on the preoperative liver function test and the evaluation of tumor character. For advanced HCC patients with vascular invasion, non-surgical treatments such as PEIT or TACE are not indicated, and surgical intervention can be an effective modality to improve their survival. Improvements of surgical technique and perioperative management have decreased fatal complications at a major liver resection and allowed us to carry out liver resection on patients with advanced HCC.     

Exercise tolerance in asymptomatic elderly men with fluoroscopically detected coronary artery calcification

STUDY OBJECTIVE: The value of detecting coronary artery calcification (CAC), by cardiac imaging, for the diagnosis of coronary artery disease (CAD) in asymptomatic middle-aged men has been demonstrated. However, the incidence of CAC increases with age. The functional significance of CAC remains unknown in asymptomatic elderly men. The purpose of this study is to explore whether CAC in asymptomatic aging men signifies the presence of cardiovascular dysfunction during exercise. DESIGN: This study was designed to address whether elderly asymptomatic men, selected because they have CAC, have reduced exercise tolerance due to functionally significant CAD. Participants and setting: Thirty-eight asymptomatic male volunteers (ages 50 to 75 years, mean [+/-SD] 64+/-7 years) with a normal resting ECG and at least one coronary risk factor, in a population study. Nineteen subjects had CAC detected by digital subtraction fluoroscopy in at least two major coronary arteries, and 19 subjects had no identifiable CAC. METHODS AND RESULTS: Each subject underwent a symptom-limited incremental exercise test with 12-lead ECG monitoring and respiratory gas analysis. Four indexes of exercise oxygen transport were evaluated: peak oxygen uptake (VO2), lactic acidosis threshold, peak VO2/heart rate ratio, and VO2 relative to a work rate increase. Eleven of 38 subjects (28%) were found to have reduced oxygen transport, which was defined as an abnormal reduction in more than two of the above four indexes of oxygen transport. Five of the 11 subjects with reduced oxygen transport had CAC, and 6 subjects did not (not significant). Only one subject with CAC had exercise ST depression. CONCLUSION: Significant CAC in asymptomatic men over age 50 does not signify exercise limitation due to CAD.     

Encephalitis in mice inoculated intranasally with an influenza virus strain originated from a water bird

A retrospective chart review of 43 patients who underwent technetium 99m (Tc-99m) sestamibi scans from June 1995 to January 1997 was performed. Only those who underwent subsequent parathyroid exploration with excision were included in the study. Twenty subjects (13 women and seven men) were included in the study. Ages ranged from 21 to 84 years (mean, 58 years). All patients had laboratory values and clinical findings consistent with primary hyperparathyroidism. Two patients had preoperative magnetic resonance imaging (MRI) scans (one patient with recurrent disease), and one had a preoperative computed tomography (CT) scan. The remaining patients had the sestamibi scan as the only preoperative localization study. There were 18 pathologic diagnoses of parathyroid adenoma and two of parathyroid hyperplasia. Sestamibi failed to correctly identify the location of the parathyroid lesion in two cases. In 18 cases the preoperative sestamibi scan correctly localized the lesion, a predictive value of 90%. We conclude that the Tc-99m sestamibi scan is an accurate preoperative tool that can be used as a single modality to localize parathyroid adenomas.     

Criteria for Selecting the Private-Sector Partner in Public–Private Partnerships

A critical issue in public–private partnerships (PPPs) in international infrastructure development is the selection of the right private-sector partner. This necessitates a best value source selection methodology in which the establishment of a set of appropriate selection criteria is a prerequisite. Various important selection criteria have been identified through a literature review of previous studies on critical success factors; experience drawing and lessons learning from international PPP practices; examination of selection criteria used in worldwide PPP projects; and interviews/correspondence with international PPP experts and practitioners. These identified criteria are classified into four evaluation packages for PPP projects in general: (1) financial, (2) technical, (3) safety, health, and environmental, and (4) managerial. The relative importance of these evaluation packages and the relative significance of the criteria within each package have been statistically analyzed based on a structured questionnaire survey of worldwide PPP expert opinions. These statistical analyses include validity and reliability analysis, Mann Whitney U tests, direct comparisons of mean criterion significance indexes and criterion rankings between respondents across public, private, and academic sectors, and a general rank agreement analysis across sectors for each evaluation package. These research outputs would facilitate the formulation of a multicriteria best value source selection methodology for PPP projects in general and the development of both objective and subjective evaluation criteria to select the right private-sector partner for a particular PPP project.     

Prognostic value of training-induced change in peak exercise capacity in patients with myocardial infarcts and patients with coronary bypass surgery

An inverse association between mortality and exercise capacity has been demonstrated previously in patients with coronary artery disease. Physical training generally increases exercise capacity. Only 1 study investigated the prognostic value of exercise capacity after training, but only in a limited number of patients. No data are available on the relation between mortality and the change in exercise performance with training. Peak oxygen uptake (VO2) was measured before and after a 3-month, predominantly dynamic training period in 417 patients with coronary artery disease. Apart from peak VO2, several patient characteristics, risk factors for cardiovascular disease, and exercise data were considered in a Cox proportional-hazards model. Peak VO2 had increased by 33% after the training period. During the total follow-up of 2,583 patient-years, 37 patients died. The cause of death was cardiovascular in 21. The prognostic value of peak VO2 was higher after training than before training, even after adjustment for age and other significant covariates. Cardiovascular mortality decreased more with greater increases in peak VO2 after training. The relative hazard rate of 0.98 indicates that a 1% greater increase in peak VO2 after training would be associated with a decrease in cardiovascular mortality of 2%. No differences in prognostic value and in training effects were observed between patients with myocardial infarcts and patients after coronary bypass grafting. Peak VO2, evaluated after a physical training program, and its change in response to training are independent predictors for cardiovascular mortality in patients with coronary artery disease.