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At least 19 recordsLinked to original sources
PubMed1992

[Extent and degree of coronary flow reserve in hypertrophic cardiomyopathy assessed by delta Fract map unfolding coronary flow reserve index].

Patients with hypertrophic cardiomyopathy (HCM) are known to have ischemic events and decreased coronary flow reserve, but the variabilities in the site and degree of fall between patients with this disease have not been clarified. To elucidate these variabilities, we performed exercise myocardial single photon emission computed tomography (SPECT) using double dose method in 30 patients with HCM (6 with obstruction, 17 with non-obstruction, 7 with apical hypertrophy) and 10 normals. Then, the delta Fract (coronary flow reserve index) map was obtained for each subject. Exercise and then rest Tl-201 myocardial scintigraphy were performed after administration of Tl-201. The data were reconstructed, making the circumferential curves from the same level of short-axis imaging during exercise and at rest. By subtracting the values at rest from the values during exercise, which were divided by the values at rest, delta Fract in each frame was obtained, and described on the unfolded map. The extent and degree of coronary flow reserve were visually estimated by this delta Fract map. Patients were categorized into 5 groups: diffuse fall of coronary flow reserve (D-type), 6 cases; localized fall of the septum or lateral wall (L-type), 5 cases; fall of apical region (A-type), 5 cases; mild fall (M-type), 6 cases; and normal pattern (N-type), 8 cases. We concluded that delta Fract map is useful for evaluating the extent and degree of coronary flow reserve in HCM.

Adult↗
PubMed1992

Comparison of drug use rates for reservation Indian, non-reservation Indian and Anglo youth.

Rates of drug use and involvement were compared for three groups: Indian youth living on reservations, Indian youth living off reservations and Anglo youth. A consistent pattern emerged, showing the lowest rates of use among Anglo youth, higher rates among non-reservation Indian youth, and the highest rates among Indian youth on reservations. Rates of tobacco use, both smoked and smokeless, and marijuana use are especially high for Indian youth. Indian youth also show a pattern of earlier initiation to drug use. Gender differences reveal slightly higher rates of use for males, although the differences are not great enough to suggest that prevention efforts for males should have a higher priority.

Adolescent↗
PubMed1992

Drug use of friends: a comparison of reservation and non-reservation Indian youth.

There is not much drug use at school, but reservation youth are most likely, non-reservation Indian youth next most likely, and non-Indian youth least likely to have used drugs at school. Alcohol and drugs are used most frequently at weekend parties and at night with friends. Reservation youth are twice as likely as the others to have used alcohol while driving around and three times more likely to have used drugs while driving around. Drugs are used with friends. Heavy drug users are more likely to have friends who use drugs and friends who encourage drug use and are less likely to have friends who would try to stop them from using drugs.

Adolescent↗
PubMed1990

Methoxyisobutylisonitrile (MIBI) Tc 99m SPECT to establish a correlate to coronary flow reserve, the perfusion reserve, from global and regional myocardial uptake after exercise and rest.

With 99mTc-MIBI SPECT and a 4 h exercise (E: 150 MBq iv) and rest (R; 800 MBq iv) protocol, global and regional left ventricular (LV) myocardial uptake was determined in 70 patients with angiographically confirmed coronary heart disease (CHD) and in 10 controls. The aim was to establish an E/R ratio as a correlate to coronary vascular reserve, representing perfusion reserve (PR). E/R ratios, obtained from total LV myocardium or from normal or impaired regions, were greater than 1.19 under all conditions, indicating the presence of higher flow during exercise than at rest (even in areas of low flow). Global PR separated (P less than 0.01) controls (1.63 +/- 0.21; mean +/- SD) from severely diseased patients (1.29 +/- 0.14 in 2- or 3-vessel disease) only. Improved differential diagnosis was gained from calibrating the regional E/R ratio to regional differences (E minus R) of uptake. For the left ventricle regional PRs (RPR) for 25 ROIs of the target, framing the myocardium, were determined. RPR at the regional maximum of 99mTc-MIBI uptake was similar in both controls (1.66) and patients (1.63), indicating a high probability of meeting some areas with functionally normal perfusion in patients with CHD. RPR allowed sufficient separation (P less than 0.025) concerning the degree of coronary artery stenosis (RPR in occlusion, 0.26; stenosis greater than 75%, 0.39; less than 75%, 0.56). In controls, the overall value for RPR was 1.14 +/- 0.28 (P less than 0.001). LV global PR and RPR were useful in separating patients with CHD vs controls and in classifying the severity of vascular stenosis.

Adult↗
PubMed1992

[Rational blood reservation for elective surgery. A prospective evaluation of blood reservation, use of transfusions and resources].

Danish and international studies have documented that preoperative blood ordering policy in elective surgery is extremely inefficient if not based on knowledge of actual transfusion frequencies and requirements. During a 12-month period, the impact of practical application of Type & Screen (T&S), and a thoroughly revised preoperative blood ordering policy in elective surgery, on crossmatch ordering, transfusion extent and safety were assessed prospectively. In addition, the effect on resource and laboratory economy was estimated, using the number of crossmatches, crossmatch to transfusion (C/T) ratio, out-dating, transfusion complications, and the proportional use of fractionated red cell products (erythrocyte concentrate and suspension) as efficiency parameters. In 86% out of 6,766 surgical procedures the recommendations were followed. A total of 1,736 patients had a preoperative cross-match of two or more units of blood and 25.1% were transfused during or within 48 hours following surgery. Only 2.4% of patients with T&S were transfused. Of the crossmatched blood 18.1% was actually transfused, and the overall crossmatch to transfusion ratio (C/T-ratio) was 5.33. In only 0.5% of operations, unexpected crossmatching and transfusions proved necessary during surgery. None of the reported transfusion complications were due to failure of the T&S procedure. During a period of increasing blood bank activities, as measured by the number of blood groupings and the blood turnover, a significant decrease in C/T-ratio and number of crossmatches was observed, corresponding to an estimated annual reduction of 11,000 crossmatches. Outdating declined from 9 to 3.2%, corresponding to savings of approximately 1,000 transfusion units annually, while the complication rate remained constant at 1.7%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Banks↗
PubMed1990

Coronary flow reserve as a physiologic measure of stenosis severity.

PART I: Coronary flow reserve indicates functional stenosis severity, but may be altered by physiologic conditions unrelated to stenosis geometry. To assess the effects of changing physiologic conditions on coronary flow reserve, aortic pressure and heart rate-blood pressure (rate-pressure) product were altered by phenylephrine and nitroprusside in 11 dogs. There was a total of 366 measurements, 26 without and 340 with acute stenoses of the left circumflex artery by a calibrated stenoser, providing percent area stenosis with flow reserve measured by flow meter after the administration of intracoronary adenosine. Absolute coronary flow reserve (maximal flow/rest flow) with no stenosis was 5.9 +/- 1.5 (1 SD) at control study, 7.0 +/- 2.2 after phenylephrine and 4.6 +/- 2.0 after nitroprusside, ranging from 2.0 to 12.1 depending on aortic pressure and rate-pressure product. However, relative coronary flow reserve (maximal flow with stenosis/normal maximal flow without stenosis) was independent of aortic pressure and rate-pressure product. Over the range of aortic pressures and rate-pressure products, the size of 1 SD expressed as a percent of mean absolute coronary flow reserve was +/- 43% without stenosis, and for each category of stenosis severity from 0 to 100% narrowing, it averaged +/- 45% compared with +/- 17% for relative coronary flow reserve. For example, for a 65% stenosis, absolute flow reserve was 5.2 +/- 1.7 (+/- 33% variation), whereas relative flow reserve was 0.9 +/- 0.09 (+/- 10% variation), where 1.0 is normal. Therefore, absolute coronary flow reserve by flow meter was highly variable for fixed stenoses depending on aortic pressure and rate-pressure product, whereas relative flow reserve more accurately and specifically described stenosis severity independent of physiologic conditions. Together, absolute and relative coronary flow reserve provide a more complete description of physiologic stenosis severity than either does alone. PART II: Coronary flow reserve directly measured by a flow meter is altered not only by stenosis, but also by physiologic variables. Stenosis flow reserve is derived from length, percent stenosis, absolute diameters and shape by quantitative coronary arteriography using standardized physiologic conditions. To study the relative merits of absolute coronary flow reserve measured by flow meter and stenosis flow reserve determined by quantitative coronary arteriography for assessing stenosis severity, aortic pressure and rate-pressure product were altered by phenylephrine and nitroprusside in 11 dogs, with 366 stenoses of the left circumflex artery by a calibrated stenoser providing percent area stenosis as described in Part I.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiography↗
PubMed1992

Tachycardia, contractility and volume loading alter conventional indexes of coronary flow reserve, but not the instantaneous hyperemic flow versus pressure slope index.

OBJECTIVES AND BACKGROUND: Because measurements of flow reserve are often made in the setting of fluctuating hemodynamic variables that cause alterations in basal or hyperemic coronary blood flow, traditional flow reserve indexes may be difficult to interpret. Prior work in this laboratory has suggested that the instantaneous hyperemic flow versus pressure slope index is a more hemodynamically stable alternative to measures of flow reserve. Although this index has no hemodynamic dependence on changes in aortic pressure, the extent to which it is affected by other factors that alter myocardial work is unknown. Therefore, the purpose of this investigation was to analyze the effects of tachycardia (induced by atrial pacing at 10 beats/min above the basal heart rate), dobutamine infusion (10 micrograms/kg per min) and saline solution volume loading (500 ml) on measurements of traditional coronary flow reserve, the resistance reserve ratio and the instantaneous hyperemic flow versus pressure slope index. METHODS: Twenty-nine open chest anesthetized dogs were studied in four sequential stages: baseline, tachycardia, dobutamine infusion and saline solution volume loading. Traditional coronary flow reserve was defined as the ratio of hyperemic coronary blood flow to basal coronary blood flow, the resistance reserve ratio as the ratio of basal coronary resistance to hyperemic coronary resistance and the instantaneous hyperemic flow versus pressure slope index as the slope of the instantaneous relation between diastolic hyperemic coronary blood flow and diastolic aortic pressure normalized by perfusion bed weight. Hyperemia was induced by intravenous adenosine infusion (1 mg/kg per min). Mean aortic pressure was kept nearly constant during the interventions by manipulation of an aortic clamp or a vena caval snare. RESULTS: The final study group comprised 18 open chest dogs. Coronary flow reserve was significantly decreased by tachycardia (3.7 +/- 1.2 to 3.0 +/- 1.2, p < 0.0001), decreased by saline solution volume loading (3.2 +/- 1.3 vs. 2.7 +/- 0.8, p = 0.06) and significantly increased by dobutamine infusion (3.2 +/- 1.3 to 4.3 +/- 1.5, p < 0.0005). In contrast, the instantaneous hyperemic flow versus pressure slope index was not affected by the three interventions (7.4 +/- 3.1 vs. 7.3 +/- 3.3, 7.4 +/- 3.2 vs. 7.4 +/- 3.4 and 7.5 +/- 3.1 vs. 7.3 +/- 3.4, respectively, all p = NS). The changes observed in the resistance reserve ratio were of similar or greater magnitude and significance to the changes in coronary flow reserve. CONCLUSIONS: The instantaneous hyperemic flow versus pressure slope index offers a hemodynamically stable alternative to measures of vascular reserve because it is independent of moderate changes in heart rate, contractility and volume loading that may occur commonly in clinical situations.

Analysis of Variance↗
PubMed1991

[Prognostic significance of the electrocardiographic coronary reserve in stable angina].

We've studied the prognostic significance of the electrocardiographic coronary reserve, evaluated by seried effort tests, in patients with stable angina and proved coronary disease. Seventy-three patients with stable angina, who performed 2 exercise tests (basal and after vasodilator therapy) were included. It's considered variable reserve when in the second test the ST-descent improves greater than or equal to 1 mm for equal or higher double product (43 patients) and fixed reserve when it doesn't (30 patients). All of them underwent to coronariography study. The exercise test was seried each term during the first year. Clinical follow-up lasted 3 years and we considered cardiac events: myocardial infarction, unstable angina, surgery, PTCA or death. Patients with fixed reserve had higher maximal ST-descent (2.5 +/- 0.7 vs 1.9 +/- 0.6; p less than 0.05), lesser effort-time (359 +/- 144 vs 430 +/- 112; p less than 0.05), and more severe coronary disease (score: 3.5 +/- 1.5 vs 2.4 +/- 0.8; p less than 0.01) as compared with variable reserve group. Unfavorable clinic evolution was similar in both groups (44.3% in the fixed reserve group and 34.8% in the variable reserve group). We verified that 92.3% of patients with variable reserve who didn't modify its character in a year had good evolution; 76.4% of patients who changed to fixed reserve had unfavorable evolution (significant association, p less than 0.01). We conclude that in patients with variable reserve, the periodic evaluation of the reserve character has important prognostic implication.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1990

[Clinical and angiographic expression of myocardial ischemia in stable angina as a function of its coronary reserve].

We have studied the distribution of the coronary reserve, evaluated by serial effort tests, in patients with proved coronaropathy, determining the correlation between clinic (effort and mixed angina) and coronary reserve (fixed and variable), assessing angiographic findings in function to that reserve. We took 120 patients with stable angina to whom 2 effort tests were performed, basal and after vasodilator drugs. It was considered variable reserve if in the second test the S-T descend improved greater than or equal to 1 mm for a similar of greater double product and fixed when it didn't improve. In all patients coronarography was performed. Seventy two patients (60%) showed fixed reserve, 58 with effort angina (80%) and 14 (20%) with mixed. Forty eight showed variable reserve, 40 (80%) with mixed angina and 8 (17%) with effort. The group with fixed reserve had a greater S-T max. descent (2.9 +/- 0.9 vs 2.2 +/- 0.4) (p less than 0.001), a lower double product max. (221 +/- 44 vs 284 +/- 37) (p less than 0.001) and a lower maximal oxygen consumption (MVO2 7 +/- 2 vs 11 +/- 2) (p less than 0.001) than the variable reserve group. Considering the angiography, the fixed reserve group had more number of vessels affected (1.9 +/- 0.7 vs 1.4 +/- 0.5) (p less than 0.01), a higher angiographic score (4.88 +/- 2.4 vs 2.2 +/- 1.2) (p less than 0.001), a lower ejection fraction (59 +/- 8.5 vs 65 +/- 7.5) (p less than 0.001), more multivessel and descending anterior artery lesion than the variable reserve group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Relations among impaired coronary flow reserve, left ventricular hypertrophy and thallium perfusion defects in hypertensive patients without obstructive coronary artery disease.

Invasive Doppler catheter-derived coronary flow reserve, echocardiographic measurements of left ventricular hypertrophy and intravenous dipyridamole-limited stress thallium-201 scintigraphy were compared in 48 patients (40 were hypertensive or diabetic) with clinical ischemic heart disease and no or minor coronary artery disease. Abnormal vasodilator reserve (ratio less than 3:1) occurred in 50% of the study group and markedly abnormal reserve (less than or equal to 2:1) occurred in 27%. Coronary vasodilator reserve was significantly lower (2.2 +/- 0.8 versus 3.5 +/- 1.3, p = 0.003) and indexed left ventricular mass significantly higher (152.6 +/- 42.2 versus 113.6 +/- 24.0 g, p = 0.0007) in patients with a positive (n = 11) versus a negative (n = 32) thallium perfusion scan. Coronary flow reserve was linearly related in coronary basal flow velocity as follows: y = -0.17x + 4.59; r = -0.57; p = 0.00002. The decrement in flow reserve was not linearly related to the degree of left ventricular hypertrophy. Abnormal vasodilator reserve subsets found in hypertensive patients were defined on the basis of basal flow velocity, indexed left ventricular mass and clinical factors. In this series, diabetes did not cause a detectable additional decrement in flow reserve above that found with hypertension alone. These findings demonstrate that thallium perfusion defects are associated with depressed coronary vasodilator reserve in hypertensive patients without obstructive coronary artery disease. Left ventricular hypertrophy by indexed mass criteria is predictive of which hypertensive patients are likely to have thallium defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed2026

Post-intervention effectiveness of a computerized personalized cognitive stimulation program adapted according to cognitive reserve in older adults without cognitive impairment in Primary Care: A randomized clinical trial.

BACKGROUND: Cognitive reserve may influence responsiveness to cognitive interventions, yet it is rarely used to tailor computerized stimulation. OBJECTIVE: To evaluate the effectiveness of a computerized cognitive stimulation program personalized according to cognitive reserve on cognition, reserve-related activities, and digital competence in community-dwelling older adults without cognitive impairment in Primary Care. METHODS: In this randomized clinical trial, 102 adults aged &#x2265;65 years with normal cognitive performance were recruited from three primary care centers in Zaragoza, Spain, and stratified by cognitive reserve level before random allocation to intervention or control. The intervention comprised digital literacy sessions followed by 8 weeks of home-based computerized cognitive stimulation tailored to participants' cognitive reserve profiles and life history. Controls received a single group-based health education session focused on maintaining everyday cognitive activity. Outcomes were assessed at baseline and post-intervention using global cognition (MEC-35), the Cognitive Reserve Questionnaire, the Mobile Device Proficiency Questionnaire-16, and domain-specific neuropsychological tests. A total of 100 participants completed the final evaluation and were included in complete-case analyses. RESULTS: Compared with controls, the intervention group showed greater adjusted post-intervention improvements in global cognition (MEC-35 between-group difference: 1.8 points) and several cognitive measures, including temporal orientation, calculation, attention, praxis, verbal fluency, processing speed, executive functions, and verbal learning. CRQ scores and digital competence also improved, with small-to-large effect sizes. CONCLUSIONS: A computerized cognitive stimulation program adapted according to cognitive reserve appears feasible in Primary Care and may improve cognition, engagement in reserve-related activities, and digital competence in older adults without cognitive impairment.

Humans↗
PubMed1991

Relationship of left ventricular mass to impairment of coronary vasodilator reserve in hypertensive heart disease.

An impaired coronary vasodilator reserve has been demonstrated in all stages of hypertensive heart disease but is most likely in the setting of hypertrophy. The decrease in coronary flow reserve has, however, not been predictable previously. We postulated that flow reserve depression might be related to a left ventricular mass threshold. Seventy-two patients (82% with hypertension) with suspected ischemic heart disease who were found to be free of significant coronary artery disease at cardiac catheterization were evaluated utilizing the intracoronary Doppler catheter and two-dimensional directed M-mode echocardiography for determination of coronary flow reserve and left ventricular mass. For left ventricular mass indexed (LVMI) by body surface area (BSA) greater than or equal to 50% above normal using established gender-specific norms, American Society of Echocardiography (ASE) and PENN methods (correction of LV mass by regression equation agreeing with necropsy estimates of mass) predicted impairment of flow reserve (p = 0.005 and 0.009, respectively). Unindexed left ventricular mass and LVMI by height were not helpful in this regard. Using the ASE method for LV mass determination, coronary flow reserve was moderately depressed (2.4 +/- 1.0) for those with LVMI greater than or equal to 50% above normal; in comparison, flow reserve was normal (3.5 +/- 1.3) for those with LVMI less than 50% above normal. A rare patient was able to maintain a normal flow reserve when ASE- and Penn-indexed mass estimates were greater than or equal to 50% above normal, but only in the setting of a markedly elevated mean arterial pressure.

Adult↗