Hiroyuki Daida

Peak exercise blood pressure stratified by age and gender in apparently healthy subjects

OBJECTIVEnTo determine the peak blood pressure responses during symptom-limited exercise in a large sample of apparently healthy subjects, including both men and women over a wide range of ages.nnnDESIGNnWe retrospectively studied the blood pressure response during maximal treadmill exercise testing with use of the Bruce protocol in apparently healthy subjects.nnnMATERIAL AND METHODSnPeak exercise blood pressures in 7,863 male and 2,406 female apparently healthy subjects who underwent a screening treadmill exercise test with the Bruce protocol between 1988 and 1992 were analyzed by age and gender.nnnRESULTSnIn this large referral population of apparently healthy subjects, peak exercise systolic and diastolic blood pressures and delta systolic blood pressure (rest to peak exercise) were higher in men than in women and were positively associated with age. In men, the 90th percentile of systolic blood pressure increased from 210 mm Hg for the age decade 20 to 29 years to 234 mm Hg for ages 70 to 79 years; the corresponding increase among women was from 180 mm Hg to 220 mm Hg. Delta diastolic blood pressure also increased with advancing age. The difference in peak and delta systolic blood pressures between men and women seemed to decrease after age 40 to 49 years. Exercise hypotension, defined as peak exercise systolic pressure less than rest systolic pressure, occurred in 0.23% of men and 1.45% of women and was not significantly related to age.nnnCONCLUSIONnOverall, peak exercise systolic and diastolic, as well as delta systolic, blood pressures were higher in men than in women and increased with advancing age. The reported data will enable clinicians to interpret more accurately the significance of peak exercise blood pressure response in a subject of a specific age and gender and will allow investigators to define exercise hypertension in statistical terms stratified by age and gender.

Relation of saphenous vein graft obstruction to serum cholesterol levels

Objectives. To determine the potential of lipid-lowering therapy to reduce saphenous vein graft obstruction, we retrospectively studied the association between graft obstruction and serum cholesterol levels. Background. Atherosclerosis is the major cause of vein graft obstruction. Approximately 50% of grafts are occluded by 10 years after operation. It remains to be established whether lipid control affects long-term graft survival. Methods. We carried out a retrospective review of all 284 patients who had undergone coronary artery bypass graft surgery at Juntendo University Hospital between 1976 and 1991 and met the following additional criteria: at least one saphenous vein graft, repeat coronary arteriography at some point after coronary artery bypass graft surgery and a serum cholesterol level >200 mg/dl before operation. Saphenous vein graft obstruction rates were compared among three groups classified by serum cholesterol levels at follow-up arteriography: group I 240 mg/dl. A vein graft was considered obstructed if it was narrowed by ->70%. Results. In group I, 88% of grafts were not obstructed 7 years after operation. The respective rates were 61% in group II and 57% in group III (p < 0.005). This relation was true for vein grafts to the left anterior descending and other coronary arteries. Conclusions. Lower serum cholesterol levels are associated with lower rates of vein graft obstruction for up to 7 years. This suggests that cholesterol-lowering therapy may improve long-term saphenous vein graft survival after coronary artery bypass surgery. (JAm CoU Cardioi 1995;25:193-7)

Sequential assessment of exercise tolerance in heart transplantation compared with coronary artery bypass surgery after phase II cardiac rehabilitation

To investigate the improvement in exercise capacity of transplant patients after an early postoperative (phase II) cardiac rehabilitation program during the first year after surgery, we analyzed retrospectively exercise capacity within 3 months (at the completion of phase II rehabilitation) and 1 year after surgery in 17 orthotopic heart transplantation patients (15 men and 2 women) and 17 age- and gender-matched coronary artery bypass graft (CABG) patients. All patients participated in a phase II cardiac rehabilitation exercise program followed by a home-based exercise program. At the completion of phase II cardiac rehabilitation, mean peak oxygen (VO2) adjusted for body weight in heart transplant patients was not significantly different from that in CABG patients (19.7 +/- 3.7 vs 21.9 +/- 4.1 ml/kg/min), and oxygen pulse at peak exercise did not differ between the 2 groups (11.5 +/- 2.5 vs 12.6 +/- 2.4 ml/beat). Between 3 months and 1 year after surgery, CABG patients had a marked increase in exercise time, increase in heart rate from rest to peak exercise (heart rate reserve), peak VO2, and oxygen pulse. In contrast, heart transplant patients had a significant but only modest increase in peak VO2, and were much more limited in exercise capacity at 1 year than were CABG patients (21.3 +/- 3.9 vs 27.4 +/- 4.7 ml/kg/min, p <0.0001). In our limited patient population, usual phase I rehabilitation with subsequent home-based exercise training was inadequate to improve the exercise capacity of heart transplant patients, and different rehabilitation protocols, such as long-term supervised exercise training, specific to this patient group may be indicated.

Comparison of peak exercise oxygen uptake in men versus women in chronic heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

Results of exercise testing in 150 patients with chronic heart failure show that women were characterized by shorter exercise time, peak oxygen consumption, and lower peak oxygen pulse than men. There was a 4.1-ml/kg/min difference in peak oxygen uptake between genders after the adjustment of age, peak heart rate, respiratory exchange ratio, ejection fraction, and etiology of heart failure.

Evaluating the effectiveness of dyslipidemia control strategies

While cost-effectiveness analyses of anti-hyperlipidemia programs featuring drug treatment suggest that the best use of public dollars is to delay treatment until an individual develops coronary heart disease, a comprehensive hyperlipidemia treatment policy must take a broader perspective. The high case-fatality rates of patients exhibiting first manifestations of coronary heart disease, the limited population impact of interventions aimed solely at high risk groups, the cost of testing to identify the high risk segment of the population, the social origins of the behavioral risk factors for coronary heart disease, and the perspective of the individual must also be considered. Available data suggest that the best public policy to control the burden of heart disease is one with two components: On the one hand, all individuals without clinically manifest heart disease would be encouraged to adopt healthy behaviors without an attempt to sort the population into high and not high risk groups. On the other hand, the risk factors of individuals who already have coronary heart disease would be treated aggressively with a case-management system of follow-up. The data that support this conclusion are presented in this paper.

Are Coronary-Care Unit Changes in Therapy Associated With Improved Survival of Elderly Patients With Acute Myocardial Infarction?

OBJECTIVEnTo determine whether changes in coronary-care unit therapy for elderly patients with acute myocardial infarction have been associated with improved survival.nnnMATERIAL AND METHODSnWe conducted a retrospective cohort analysis of all patients 70 years of age or older from Olmsted County, Minnesota, who were hospitalized in a coronary-care unit in this county for the treatment of acute myocardial infarction during one of three periods: 1976 through 1978, 1987 through 1989, and 1991. The effect of aspirin, heparin, beta-blockers, thrombolysis, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting on these elderly patients with acute myocardial infarction was assessed.nnnRESULTSnImprovement in 30-day survival was significant for patients 80 years of age or older (45%, 69%, and 78% in 1976 through 1978, 1987 through 1989, and 1991, respectively; P = 0.01 for the trend) but not for patients 70 to 79 years of age (77%, 76%, and 81% for the three time periods, respectively; P = 0.65 for the trend). The opposite pattern was observed for survival in the period more than 30 days after the event. More intensive treatment in the hospital was associated with better 30-day survival (P < 0.0001).nnnCONCLUSIONnThe improved survival of the elderly patients with acute myocardial infarction in these cohorts can be accounted for by changes in the therapy they received in the coronary-care units.

Agreement and coding reliability of the Minnesota and Mayo electrocardiographic coding systems

PROBLEMnTo determine whether diagnoses of myocardial infarction assigned by a system that uses Marquette 12SL electrocardiographic (ECG) codes with manual over-reading agree with diagnoses assigned by Minnesota ECG codes.nnnSTUDIES UNDERTAKENnAgreement and recode reliability of Minnesota and Mayo coding systems based on 768 ECGs plus chest pain history and serum enzyme values were analyzed for a stratified random sample of 141 patients with an event in 1990 or 1991 coded as HICDA 410.x, 411, 413 or 796.9. The population was reconstructed from the stratified random sample so that population-based inferences could be made from the analysis.nnnRESULTSnFor the stratified random sample, exact agreement on 4 categories (evolving diagnostic, diagnostic, equivocal, or other ECG) between Mayo and Minnesota ECG coding was 53.9% (kappa = 0.37 +/- 0.05). Code-recode agreement was higher for Minnesota coding (83.0%; kappa = 0.74 +/- 0.05) compared with Mayo coding (73.8%; kappa = 0.64 +/- 0.05). The same pattern was present for the reconstructed population. For coding myocardial infarction based on the ECG, serum enzyme levels, and the presence or absence of ischemic chest pain, agreement between Mayo and Minnesota coding was 84.4% (kappa = 0.72 +/- 0.05) based on the stratified random sample and 81.7% (kappa = 0.67 +/- 0.06) based on the reconstructed population. For the stratified random sample, reliability of diagnosis of myocardial infarction was 93.6% (kappa = 0.88 +/- 0.04) for the Minnesota system and 94.3% (kappa = 0.90 +/- 0.03) for the Mayo system.nnnCONCLUSIONnECG interpretation by the Mayo and Minnesota coding systems differs significantly, and Mayo ECG coding is less reliable than Minnesota ECG coding. Coding of myocardial infarction on the basis of ECGs, serum enzymes, and ischemic chest pain, however, is equally reliable for both systems.

The Epidemiology of Coronary Heart Disease: Case Studies of Five Countries

Epidemiologic techniques allow us to use “natural experiments” to investigate the conditions that lead to disease. This article reviews the critical early observations about the epidemiology of coronary heart disease (CHD) and illustrates the key observations with data from five countries. These data suggest that only populations that consume a diet that is high in saturated fat or milk products develop high rates of CHD. Both smoking and hypertension promote the disease in the presence of an atherogenic diet but are insufficient by themselves to cause epidemic CHD. Both France and Japan have disease rates that are lower than would be predicted from the cholesterol, blood pressure, and smoking levels in their populations. The antioxidant effects of vegetables and the paucity of dairy products appear to be the factors that are protecting the French population. The platelet-inhibiting effects of marine oils appear to be providing protection to the Japanese population.

The transluminal attenuation gradient in coronary CT angiography

OBJECTIVE: Results of the use of the transluminal attenuation gradient (TAG) at coronary CT angiography (CCTA) to predict hemodynamically significant disease vary widely. This study tested whether diagnostic performance of TAG to predict fractional flow reserve (FFR) ≤xa00.8 is improved when applied separately to subsets of coronary arteries that carry similar physiological flow. nMETHODS: 28 patients with 64xa0×xa00.5 mm CCTA and invasive FFR in ≥1 major coronary artery were retrospectively evaluated. Two readers assessed TAG in each artery. The receiver operating characteristic (ROC)xa0area under the curve (AUC) was used to assess the diagnostic performance of TAG to detect hemodynamically significant disease following a clinical use rule [negative: FFRxa0>xa00.8 or ≤xa025% diameter stenosis (DS) at invasive catheter angiography; positive: FFRxa0≤xa00.8 or ≥xa090% DS at invasive catheter angiography]. ROC AUC was compared for all arteries pooled together, vs separately for arteries carrying similar physiological flow (Group 1: all left anterior descending plus right-dominant left circumflex; Group 2: right-dominant RCA plus left/co-dominant left circumflex). nRESULTS: Of the 84 arteries, 30 had FFR measurements, 30 had ≤25% DS and 13 had ≥90% DS. 11 arteries with 26-89% DS and no FFR measurement were excluded. TAG interobserver reproducibility was excellent (Pearson rxa0=xa00.954, Bland-Altman bias: 0.224 Hounsfield unitxa0cm). ROC AUC to detect hemodynamically significant disease was higher when considering arteries separately (Group 1 AUCxa0=xa00.841, pxa0=xa00.039; Group 2 AUCxa0=xa00.840, pxa0=xa00.188), than when pooling all arteries together (AUCxa0=xa00.661). nCONCLUSION: Incorporating information on the physiology of coronary flow via the particular vessel interrogated and coronary dominance may improve the accuracy of TAG, a simple measurement that can be quickly performed at the time of CCTA interpretation to detect hemodynamically significant stenosis in individual coronary arteries. Advances in knowledge: The interpretation of TAG may benefit by incorporating information regarding which coronary artery is being interrogated.

Current Use of Intravascular Ultrasound in Coronary Artery Disease

Recently, most coronary interventions rely on visual assessment of the coronary lesions using angiography with all known inherent limitations. Intravascular ultrasound (IVUS) allows for the evaluation of the coronary pathology to obtain information about both the extent and nature of atherosclerotic plaque; thus, planning the intervention strategy is based on objective data. Following the advent of gray-scale IVUS, several modes had been developed to study coronary plaque composition, thus determining the predominant component of the plaque, fibrous tissue, lipid-necrotic core, or calcium, and the intervention strategy. After intervention, IVUS plays an important role in optimizing the results after stent deployment regarding stent expansion and apposition to reduce the incidence of both stent thrombosis and in-stent restenosis. This review discusses the basic role of IVUS in evaluating plaque structure and parameters to optimize results after coronary intervention in light of recent evidence.