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Biomedical subjects

T Fudo

Publications and source records attributed to T Fudo.

At least 19 recordsLinked to original sources
PubMed1997

Fate of collateral vessels after successful coronary angioplasty in patients with effort angina.

OBJECTIVES: The purpose of the present study was to evaluate whether severe restenosis after percutaneous transluminal coronary angioplasty (PTCA) promotes collateral development and whether successful dilation regresses collateral vessels. BACKGROUND: It is well known that in the presence of severe coronary stenosis, native collateral arterioles mature to small coronary arteries with several layers of smooth muscle cells. However, it remains unclear whether well developed collateral vessels regress after removal of coronary stenosis. METHODS: The study group comprised 41 patients who underwent elective PTCA for effort angina due to single-vessel disease, followed by repeat PTCA to treat restenosis. We classified the patients into three groups depending on the change in baseline Thrombolysis in Myocardial Infarction (TIMI) flow grade of the ischemia-related artery at initial and repeat PTCA, and we compared the extent of ST segment elevation at 1 min of the first balloon inflation between the two procedures. The average interval from initial to repeat PTCA was 125 days. RESULTS: The three patient groups comprised group A, 12 patients with decreased flow grade because of severe coronary restenosis; group B, 12 patients with increased flow grade who had severe initial stenosis and relatively mild restenosis; and group C, 17 patients with unchanged flow grade. In the presence of comparable rate-pressure products at initial and repeat PTCA, patients in group A had significantly greater ST segment elevation (p < 0.01) at initial than at repeat PTCA (mean +/- SD 0.42 +/- 0.31 vs. 0.13 +/- 0.22 mV). In group B, ST segment elevation was significantly less at initial than at repeat PTCA (0.13 +/- 0.25 vs. 0.19 +/- 0.17 mV, p < 0.05), and in group C, it was comparable at the two procedures (0.37 +/- 0.32 vs. 0.35 +/- 0.33 mV, p = 0.50). CONCLUSIONS: These findings indicate that severe restenosis after PTCA promotes collateral development and that successful dilaton regresses collateral vessels during a relatively short period of time.

Aged↗
PubMed1996

Relation between preexistent coronary collateral circulation and the incidence of restenosis after successful primary coronary angioplasty for acute myocardial infarction.

OBJECTIVES: The purpose of this study was to test the hypothesis that the incidence of restenosis after primary percutaneous transluminal coronary angioplasty for acute myocardial infarction is largely influenced by the preexistent coronary collateral circulation to the infarct-related coronary artery. BACKGROUND: The occurrence of restenosis after coronary angioplasty is the most serious limitation of this procedure. However, prediction of restenosis is difficult. Severe preexistent stenosis of the infarct-related coronary artery causing the development of collateral circulation may result in a high frequency of restenosis. METHODS: The study group consisted of 152 consecutive patients undergoing primary coronary angioplasty within 12 h after the onset of a first acute myocardial infarction. Of this group, 124 patients were angiographically followed up during the convalescent period of infarction and were classified into two groups according to the extent of preexistent collateral circulation to the infarct-related coronary artery. RESULTS: Restenosis occurred in 26 (38%) of 69 patients with poor or no collateral circulation (group A) in contrast to 35 (64%) of 55 patients with good angiographic collateral circulation (group B, p < 0.005). The frequency of preinfarction angina was significantly lower (p < 0.05) in group A (26% [18 of 69]) than in group B (44% [24 of 55]). CONCLUSIONS: These findings indicate that the presence of well developed collateral circulation to the infarct-related coronary artery predicts a higher frequency of restenosis after primary coronary angioplasty. The difference in restenosis rates observed between the patients with and without good collateral circulation probably reflects the impact of underlying severity of stenosis on the long-term outcome after coronary angioplasty.

Aged↗
PubMed1995

Modification of the circadian variation of symptom onset of acute myocardial infarction in diabetes mellitus.

BACKGROUND: The effects of diabetes mellitus and its treatment on the circadian variation of symptom onset in acute myocardial infarction were examined. METHODS: We obtained the time of symptom onset in 336 patients who had suffered acute myocardial infarction. RESULTS: As in earlier studies, the peak of symptom onset occurred in the late morning, between 6:01 a.m. and 12:00 noon. Although a similar circadian variation was observed in non-diabetic patients, the late-morning peak was less prominent in diabetic patients. In diabetic patients receiving treatment, however, the circadian pattern was well preserved, whereas in untreated diabetic patients there were no peaks in the distribution of symptom onset of acute myocardial infarction. CONCLUSION: These findings suggest that autonomic disturbances in diabetes mellitus may blunt the late-morning peak in the frequency of onset of acute myocardial infarction.

Aged↗
PubMed1994

[Results of surgical treatment of aortic dissections].

From January 1989 to September 1993, 59 consecutive patients (35 males and 24 females, mean age 59.6 years old) underwent surgical repair of aortic dissection on the cardiovascular surgical unit at Takeda Hospital. The type of aortic dissection were classified according to Stanford University criteria. Twenty-two patients had acute type A (Ac-A), 10 had chronic type A (Ch-A), 4 had acute type B (Ac-B), and 23 had chronic type B (Ch-B) dissection. Seventeen dissections (29%) in the entire group of 59 cases had ruptured (including cardiac tamponade, pleural effusion and hemoptysis etc.). Ischemia of lower extremity occurred in 7 patients and ischemia of visceral organs in 3 patients. Type A dissection were approached via a median sternotomy and cardiopulmonary bypass with systemic hypothermia. Type B dissections were approached through a left postrolateral thoracotomy. Left heart bypass (left atrial-femoral in 8 cases) and partial cardiopulmonary bypass (femoral-femoral in 12 cases) generally were utilized. Resection of intimal tear and replacement of aorta with vascular grafts (including aortic arch in 19 cases) were performed in most patients and primary closure of the intimal tear was performed in 9 cases using GRF. The over-all operative mortality rate was 36% (8/22) for Ac-A, 20% (2/10) for Ch-A, 25% (1/4) for Ac-B, 22% (5/23) for Ch-B. Main causes of operative death was perioperative brain damage. It is necessary to improve the operative mortality for Ac-A dissections (especially in replacement of aortic arch and arch vessels). Further researches are needed regarding optimal methods of the cerebral protection during reconstruction of aortic arch.

Adult↗
PubMed1992

Clinical evaluation of cardiac function by ambulatory ventricular scintigraphic monitoring (VEST): validation and study of the effects of nitroglycerin and nifedipine in patients with and without coronary artery disease.

Global left ventricular function and ECGs were continuously monitored by radionuclide ambulatory ventricular function monitoring (VEST) and validated against multigated blood pool analysis (MUGA) and left ventriculography in 26 subjects (study 1). Ejection fraction by VEST (Y) showed good correlation with Y = 5.5 +/- 0.79 X (r = 0.91), Y = 1.7 +/- 0.86 X' (r = 0.91), and Y = 11.6 + 0.68 X" (r = 0.82) to sitting and supine MUGA and left ventriculography, respectively. In study 2 left ventricular function and ECGs were evaluated at rest and during exercise without any drug (control), with nitroglycerin, and with nifedipine in 21 patients with coronary disease (group I) and six normal subjects (group II). In group I abnormal ejection fraction responses (exercise increase less than or equal to 6%) during the control exercise period were found in 15 patients (71%), ST segment abnormalities in seven (33%), and chest pain in four (18%). Control exercise increased end-diastolic volume (100 to 112 +/- 8%) and end-systolic volume (53 +/- 15% to 63 +/- 22%) and decreased the ejection fraction (47 +/- 15% to 43 +/- 21%). The ejection fraction during exercise increased after nitroglycerin (50 +/- 22%) or nifedipine (54 +/- 21%) (p less than 0.05). In group II the ejection fraction was unchanged between rest and exercise with or without nitroglycerin or nifedipine. Thus combined radionuclide and ECG monitoring by VEST could detect changes in left ventricular function at rest and during exercise over a prolonged period and demonstrated that nitroglycerin and nifedipine improved cardiac function in the ischemic setting with an increased ejection fraction in the upright position.

Coronary Disease↗
PubMed1992

Coronary risk factors used to predict coronary artery disease by logistic regression analysis.

Risk factor analysis in coronary artery disease was conducted in 303 patients who underwent coronary arteriography to identify associations between personal characteristics and the prevalence of coronary heart disease. Age, sex, obesity, smoking, alcohol intake, hypertension, diabetes mellitus, serum uric acid, total cholesterol, LDL- and HDL-cholesterol, triglyceride, and atherogenic indices were statistically analyzed. All 13 variables were first compared between patients with positive and negative ergonovine tests. Only total cholesterol was significantly different, while significant differences in age, sex, history of diabetes, total cholesterol, LDL- and HDL-cholesterol, triglyceride and atherosclerotic indices were observed between patients with and without organic coronary artery stenosis. A multivariate analysis was performed, and the resulting equation was tested using the remaining patients. Logistic analysis of all 13 variables identified 5 (age, sex, diabetes mellitus, LDL- and HDL-cholesterol) which accounted for the differences between patients with and without significant coronary artery disease and that were validated in the test group. The sensitivity for prediction of coronary artery disease was 75.8%, specificity 68.5%, and predictive accuracy 71.5% in the test group. Thus, risk factor analysis appears to be very valuable in screening subjects with high-risk organic coronary stenosis and in optimizing the preventive and therapeutic modalities, but not in predicting vasospastic subjects.

Cholesterol↗
PubMed1991

Evaluation and clinical use of early washout ratio of thallium-201 in normal and ischemic myocardium after dipyridamole-induced vasodilation using ring-type emission computed tomography.

Using newly developed ring-type emission computed tomography (SPECT), we investigated the washout ratio (WR) of T1-201 in the myocardium quantitatively with fast dynamic scanning after infusion of dipyridamole (0.57 mg/kg), and assessed the feasibility of early WR as a marker to detect coronary artery disease. Twenty-three patients with and 8 patients without coronary artery disease had serial SPECT images obtained every 5 min for 45 min and at 180 min after dipyridamole and subsequent T1-201 injection. The best appropriate transaxial slice was selected for WR analysis. Most appropriate diagnostic time was 25 min after infusion of T1-201 (WR-25). Normal WR-25 was 7.1 +/- 4.0%, 5.9 +/- 3.1% and 7.1 +/- 2.3% at the septum, anterior and lateral wall, respectively. Sensitivity, specificity and accuracy to identify coronary stenosis greater than 50% with a usage of abnormal WR-25, defined as WR-25 less than (mean of normals--1SD) in each region of inferest of the left ventricle (LV), were 96%, 100% and 97%, respectively. These results were better than those achieved by visual analysis (sensitivity 78%, specificity 100%, accuracy 84%). In patients with single as well as multivessel disease, the regional accuracy in assessing stenosis of more than 50% in the left anterior descending artery (LAD) and left circumflex artery (LCX) by WR-25 was 94% and 83%, respectively, which was significantly better than using visual methods (LAD 72% and LCX 50%; p less than 0.05). Thus, evaluation of early washout ratios (WR-25) after dipyridamole injection is a valuable method to increase sensitivity in assessing regional myocardial perfusion abnormality and is helpful in detection of ischemic heart disease, even with multivessel disease.

Adult↗
PubMed1991

[Clinical features of aortic dissection with early thrombosis of the false lumen].

There are cases of dissecting aortic aneurysm in which thrombotic formation occurs in the false lumen at an early stage, preventing dissection of the vessel wall and enlargement of the aneurysm. We studied such early thrombotic obliteration of false lumina in 12 (28.6%) of 42 patients with dissecting aortic aneurysm who underwent transesophageal two-dimensional echocardiography in the acute phase from June 1986 to October 1989. It was the first employment of a transesophageal approach at our hospital. In this study, we examined the clinical profiles of these patients as well as the usefulness of transesophageal two-dimensional echocardiography in establishing the diagnosis of dissecting aortic aneurysm and characterizing the disease. The patients were classified as Type I (2 patients) and Type III (10 patients; 6 Type IIIa and 4 Type IIIb) according to DeBakey's classification. The minimum and mean intervals from the onset of symptoms to transesophageal two-dimensional echocardiography were 1.5 hours and a mean of 38.2 hours, respectively. These results indicated that thrombotic obliteration of the false lumen had already occurred at a very early stage in some patients. The maximum diameter of the descending aorta was mean 37.6 mm with only 2 patients having that of 40 mm or more. Since left intrapleural hemorrhage was observed in these 2 patients (1 received emergent replacement of the descending aorta), enlargement of the aortic diameter may be indicative of unpredictable outcome, even in patients with early thrombotic obliteration of the false lumen. The long-term clinical course was favorable in all patients, including those who were treated surgically, over a mean follow-up period of 14.5 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Effects of nifedipine on cardiac function in patients with coronary artery disease evaluated with ambulatory radionuclide monitoring.

The effects of nifedipine on left ventricular function were evaluated in 17 patients with coronary artery disease with an ambulatory radionuclide detector (VEST). Hemodynamic data were recorded continuously at rest and during upright bicycle ergometer exercise before and 30 minutes after 10 mg of oral nifedipine administration. The heart rate increased and the resting systolic blood pressure decreased significantly with nifedipine. The end-diastolic and end-systolic volumes during exercise were significantly reduced and EF increased during exercise after nifedipine administration. These salutary hemodynamic responses of nifedipine appear to be beneficial for patients with effort angina pectoris.

Aged↗
PubMed1990

[Evaluation of antihypertensive therapy by ambulatory blood pressure monitoring and establishment of the level of antihypertensive goal on the circadian rhythm of blood pressure].

We have developed a new method for the evaluation of antihypertensive therapy on the circadian rhythm of blood pressure and attempted to determine the indications for antihypertensive therapy and the level of antihypertensive goal. Blood pressures were measured for 24 hours by the use of ambulatory blood pressure monitoring using 630 (ABPM-630) in 50 normotensives, 50 untreated hypertensives and 50 hypertensives undertreatment with various antihypertensive drugs (110 males and 40 females, with a mean age of 53.4 +/- 13.3 yrs). Blood pressure profiles were prepared for determination of the hyperbaric and hypobaric indexes. According to the WHO's definitions for blood pressure, the hyperbaric index was defined as the area above 140 mmHg in systolic blood pressure or 90 mmHg in diastolic blood pressure, and the hypobaric index, as the area below 100 mmHg or 60 mmHg, respectively. The criteria of the hypobaric index was obtained from the mean basal blood pressure (the lowest blood pressure during sleep) of the 50 normotensives. The mean hyperbaric index of the 50 normotensives was 20.4 +/- 40.2/5.5 +/- 15.3 (systole/diastole) mmHg.hour/day and the mean hypobaric index, 12.2 +/- 22.5/9.0 +/- 24.0 mmHg.hour/day. The 50 untreated hypertensives showed a mean hyperbaric index of 281.8 +/- 197.0/156.0 +/- 126.1 mmHg.hour/day and a mean hypobaric index of 0.1 +/- 0.6/0.3 +/- 1.5 mmHg.hour/day. Comparison of the indexes before and after treatment with various antihypertensives showed that a decrease in the hyperbaric index without an increase in the hypobaric index was the most optimal reduction of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Silent myocardial ischemia in patients with myocardial infarction: evaluation with positron emission computed tomography.

To evaluate myocardial blood flow and glucose utilization, N-13 ammonia and F-18 deoxyglucose positron emission tomography were performed in 33 patients with myocardial infarction. The N-13 ammonia study was performed at rest and during supine exercise, and the F-18 deoxyglucose was done at rest after greater than or equal to 5 hours of fasting. Based on angina, exercise-induced hypoperfusion, and deoxyglucose uptake, 3 groups of patients were classified; 10 patients in group I (neither angina nor exercise induced hypoperfusion), 8 patients in group II (painless exercise-induced hypoperfusion) and 15 patients in group III (anginal patients with/without exercise-induced hypoperfusion). The F-18 deoxyglucose positron study demonstrated accumulation of deoxyglucose in 6 patients in group I, 7 in group II, and 14 in group III. Thus, our results indicated that a significant number of patients with antecedent myocardial infarction had exercise-induced hypoperfusion and/or altered glucose metabolism without accompanying anginal pain.

Adult↗
PubMed1989

[Usefulness of exercise Tl-201 myocardial scintigraphy: comparison with positron emission tomography].

To evaluate the usefulness of exercise Tl-201 myocardial scintigraphy, we performed positron emission tomography and conventional exercise Tl-201 emission computed tomography (ECT) in 33 patients with old anterior myocardial infarction (Q-MI: 24, non Q-MI: 9). N-13 ammonia was used as a blood flow tracer, and imaging was performed at rest and after multistage, symptom-limited ergometer exercise. After the administration of F-18 deoxyglucose (FDG) at rest in the fasting state, metabolic imagings were performed to evaluate regional exogenous glucose utilization. Tl-ECT showed fixed defects in 19 of the 33 patients, redistribution of the tracer in nine and no defects in five. All patients having partial or complete redistribution on Tl-ECT showed exercise-induced ischemia on PET with N-13 ammonia and an increased uptake of FDG in the hypoperfused region, suggesting the presence of ischemic but potentially salvageable tissues. In addition, PET with N-13 ammonia detected periinfarct ischemia in nine of the 19 with fixed defects on Tl-ECT, and increased uptakes of FDG were observed in eight of the 19. These results indicate that Tl-ECT may underestimate myocardial viability in clinically infarcted regions. Further studies are needed to determine whether restoring coronary flow improves wall motion in regions with fixed defects on Tl-ECT.

Adult↗
PubMed1989

[Serial assessment of cardiac function during and after exercise by an ambulatory ventricular function monitor (VEST)].

Cardiac function was serially assessed during and after exercise by an ambulatory ventricular function monitor (VEST) in 31 patients who received coronary angiography. Based on the study of fluctuation during the baseline recording, greater than or equal to 6% change in ejection fraction (EF) was considered significant. The serial changes in EF during exercise was divided into 5 types, including continuous increase (type A), initial increase but return to the baseline (type B), no change (type C), initial increase but later decrease below the baseline (type D), and continuous decrease (type E). Among 8 normal subjects, their EF changes during exercise showed type A in 3, type B in 2, type C in 2, and type D in 1. Among 21 patients with coronary artery disease, the EF changes showed type A in 5, type B in 4, type C in 4, type D in 5 and type E in 3. Thus, there was a significant overlap in EF response between normal and coronary patients. However, every patient showing type A and B had single-vessel disease, and 63% of them had persistent thallium defect without redistribution. After the exercise, 29 patients showed rapid increase in EF. The time to the peak EF was significantly longer in coronary patients (1.88 +/- 1.24 min) than that in normal cases (0.88 +/- 0.55 min) (p less than 0.05) particularly in patients with multi-vessel disease (2.22 +/- 1.29 min). In addition, those showing type C, D or E tended to have a longer time to peak EF and more increase in EF after exercise than those showing type A or B. These data suggest that VEST is suitable for continuous measurement of cardiac function during and after exercise which provided valuable indices for assessment of severity of ischemia in coronary artery disease.

Adult↗