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B Trimarco

Publications and source records attributed to B Trimarco.

At least 91 records · Page 5Linked to original sources
PubMed1993

Resting technetium-99m methoxyisobutylisonitrile cardiac imaging in chronic coronary artery disease: comparison with rest-redistribution thallium-201 scintigraphy.

We studied 19 patients with angiographically proven coronary artery disease and left ventricular dysfunction (ejection fraction 33% +/- 8%) by resting technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) and rest-redistribution thallium-201 cardiac imaging. Thallium and 99mTc-MIBI studies were visually analysed. Of 285 segments, 203 (71%) had normal thallium uptake, 48 (17%) showed reversible thallium defects and 34 (12%) showed irreversible thallium defects. Of these 34 irreversible thallium defects, 19 (56%) were moderate and 15 (44%) were severe. Of the corresponding 285 segments, 200 (70%) had normal 99mTc-MIBI uptake, while 37 (13%) showed moderate and 48 (17%) showed severe reduction of 99mTc-MIBI uptake. Myocardial segmental agreement for regional uptake score between initial thallium and resting 99mTc-MIBI images was 90% (kappa = 0.78). Segmental agreement between delayed thallium and resting 99mTc-MIBI images was 77% (kappa = 0.44). In particular, in 26 (9%) segments 99mTc-MIBI uptake was severely reduced while delayed thallium uptake was normal or only moderately reduced. These data suggest that although rest-redistribution thallium and resting 99mTc-MIBI cardiac imaging provide concordant results in the majority of myocardial segments, some segments with severely reduced resting 99mTc-MIBI uptake may contain viable but hypoperfused myocardium. Thus, conclusions on myocardial viability based on 99mTc-MIBI uptake should be made with caution in chronic coronary artery disease.

Adult↗
PubMed1993

Rest-injected thallium-201 redistribution and resting technetium-99m methoxyisobutylisonitrile uptake in coronary artery disease: relation to the severity of coronary artery stenosis.

To compare rest-injected thallium-201 (Tl) redistribution and resting technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) myocardial uptake in chronic coronary artery disease (CAD), 15 patients with angiographically proven CAD and left ventricular (LV) dysfunction (ejection fraction 34% +/- 9%) were studied. All patients underwent rest-redistribution Tl and resting 99mTc-MIBI cardiac imaging. Gated 99mTc-MIBI images were also acquired to assess regional LV wall motion (WM). Myocardial segments (n = 225) were divided into three groups on the basis of the degree of coronary artery stenosis: group 1 (total occlusion, n = 82), group 2 (50%-99% of stenosis, n = 84) and group 3 (< 50% of stenosis, n = 59). WM was significantly worse in groups 1 and 2 compared to group 3 (P < 0.001), but no difference was observed between groups 1 and 2. Tl and 99mTc-MIBI uptake were significantly lower in groups 1 and 2 compared to group 3 (P < 0.001), and in group 1 compared to group 2 (P < 0.001). When Tl and 99mTc-MIBI uptake were directly compared. Tl uptake was higher than 99mTc-MIBI uptake in group 1 (P < 0.001), while no significant difference was observed in groups 2 and 3. Thus, both rest-injected Tl redistribution and resting 99mTc-MIBI uptake reflected the severity of coronary artery stenosis in CAD. However, in myocardial segments with total coronary occlusion Tl uptake was significantly higher than 99mTc-MIBI uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effect of coenzyme Q10 therapy in patients with congestive heart failure: a long-term multicenter randomized study.

The improved cardiac function in patients with congestive heart failure treated with coenzyme Q10 supports the hypothesis that this condition is characterized by mitochondrial dysfunction and energy starvation, so that it may be ameliorated by coenzyme Q10 supplementation. However, the main clinical problems in patients with congestive heart failure are the frequent need of hospitalization and the high incidence of life-threatening arrhythmias, pulmonary edema, and other serious complications. Thus, we studied the influence of coenzyme Q10 long-term treatment on these events in patients with chronic congestive heart failure (New York Heart Association functional class III and IV) receiving conventional treatment for heart failure. They were randomly assigned to receive either placebo (n = 322, mean age 67 years, range 30-88 years) or coenzyme Q10 (n = 319, mean age 67 years, range 26-89 years) at the dosage of 2 mg/kg per day in a 1-year double-blind trial. The number of patients who required hospitalization for worsening heart failure was smaller in the coenzyme Q10 treated group (n = 73) than in the control group (n = 118, P < 0.001). Similarly, the episodes of pulmonary edema or cardiac asthma were reduced in the control group (20 versus 51 and 97 versus 198, respectively; both P < 0.001) as compared to the placebo group. Our results demonstrate that the addition of coenzyme Q10 to conventional therapy significantly reduces hospitalization for worsening of heart failure and the incidence of serious complications in patients with chronic congestive heart failure.

Adult↗
PubMed1993

Effects of the single and repeated administration of benazepril on systemic and forearm circulation and cardiac function in hypertensive patients.

The hemodynamic and cardiac effects of the new angiotensin-converting enzyme inhibitor, benazepril, were studied in 28 hypertensives in a double blind, placebo-controlled, between-patient study. Hemodynamic studies were performed noninvasively by means of M-mode echo (central hemodynamics and left ventricular systolic function), 2-D echo-Doppler (left ventricular diastolic function), and pulsed Doppler flowmetry (forearm circulation). Examinations were done at the end of a placebo run-in period and 3 hours after benazepril administration, both on the first day and after 6 weeks of treatment (10 or 20 mg once daily, according to patient response). In comparison with placebo, benazepril reduced systolic (p = 0.04) and diastolic (p = 0.003) blood pressure, because of a significant reduction in systemic vascular resistance (p = 0.03), while cardiac output was unchanged. Forearm vascular resistance was reduced and brachial artery compliance increased, although not to a statistically significant level (both p = 0.07). Both systolic and diastolic left ventricular function were positively influenced by the afterload reduction: End-systolic stress was reduced by 12% (p = 0.07), as was the late diastolic peak flow velocity (p = 0.02). All hemodynamic changes were evident after acute benazepril administration, and no differences was observed between acute and repeated treatment. We conclude that, similar to other ACE-inhibitors, benazepril reduces blood pressure through a reduction in vascular resistance, while cardiac output and heart rate are unaffected. These hemodynamic effects occur as early as after the first administration and exert a favorable influence on left ventricular dynamics.

Adult↗
PubMed1993

Dietary salt excess unmasks blunted aldosterone suppression and sodium retention in the stroke-prone phenotype of the spontaneously hypertensive rat.

OBJECTIVE: The mechanisms underlying the accelerating effect of high salt intake on the development of vascular injury in the stroke-prone phenotype of spontaneously hypertensive rats (SHRSP) are still not clear. The aim of the present study was to determine whether young SHRSP can excrete a dietary excess of sodium and to characterize the associated hormonal responses. METHODS: Sodium balance and hormonal parameters were studied during a 1-week high-salt diet (4% NaCl) in 6-week-old SHRSP (n = 84), in age-matched spontaneously hypertensive rats (SHR; n = 73) and in normotensive Wistar-Kyoto (WKY) rats (n = 52). RESULTS: Baseline systolic blood pressure (SBP) was similar in SHR and SHRSP and did not change significantly during the high-salt diet. SBP also remained unchanged in WKY rats during the high-salt diet. Despite similar daily sodium intakes in the three groups during the diet, the response of urinary sodium excretion to sodium loading was reduced significantly in SHRSP compared with SHR or WKY rats (F = 4.09, P < 0.001). Plasma renin activity was suppressed significantly by high salt intake in each group to a comparable extent. Plasma aldosterone concentrations were also reduced significantly by sodium loading in all strains. However, a lesser degree of aldosterone suppression was observed in the SHRSP than in both SHR and WKY rats (F = 3.01, P < 0.01). CONCLUSIONS: Young SHRSP show a blunted suppression of plasma aldosterone and a defective sodium excretion during high salt intake.

Administration, Oral↗
PubMed1993

Digitalis restores the forearm sympathetic response to cardiopulmonary receptor unloading in hypertensive patients with left ventricular hypertrophy.

OBJECTIVE: To investigate whether the impaired reflex response to cardiopulmonary baroreceptor unloading in hypertensive patients with left ventricular hypertrophy can be promptly improved by a pharmacological challenge. For this purpose we studied the effects of acute digitalis administration on cardiopulmonary baroreflex, evaluated by forearm noradrenaline spillover. METHODS: Eleven hypertensives with left ventricular hypertrophy and 10 age- and sex-matched normotensives underwent the application of -5 and -10 mmHg lower-body negative pressure (LBNP) before and after the administration of digitalis. Forearm noradrenaline spillover, measured using a tracer technique, was used to estimate the reflex sympathetic response. RESULTS: Under control conditions LBNP evoked a similar fall in right atrial pressure in the two study groups. In the normotensives there was a significant increase in forearm noradrenaline spillover. In the hypertensives no significant changes in forearm noradrenaline spillover were found. Intravenous administration of 0.02 mg/kg lanatoside C was associated with an increase in systolic blood pressure and a reduction in forearm noradrenaline spillover in both groups. In the normotensives the percentage change in forearm noradrenaline spillover induced by LBNP increased significantly in response to digitalis administration. However, digitalis restored the response of forearm noradrenaline spillover to LBNP in the hypertensives, so that no significant difference in this response was detected between the two study groups. Digitalis did not modify the effects of LBNP on cardiac pressures in either group. CONCLUSIONS: The present results demonstrate that administration of lanatoside C restores the response of forearm noradrenaline spillover to cardiopulmonary baroreceptor unloading in hypertensive patients with left ventricular hypertrophy. This indicates that the impairment of cardiopulmonary baroreflexes in these patients can be reversed by acute pharmacological treatment. Therefore, impairment of this reflex response seems to be related to functional rather than to structural abnormalities of the hypertrophied ventricle.

Digitalis Glycosides↗
PubMed1993

Insulin reduces reflex forearm sympathetic vasoconstriction in healthy humans.

Previous in vitro studies indicate that insulin modifies vascular reactivity to different agents. We have previously demonstrated that in normotensive humans physiological hyperinsulinemia is associated with an increase of forearm norepinephrine release but does not modify vascular resistance. To explore whether insulin modulates peripheral vasoconstriction induced by reflex sympathetic activation, we studied its effects on forearm hemodynamics (strain-gauge plethysmography) during graded levels of lower body negative pressure (-5, -10, -15, and -20 mm Hg, each for 5 minutes) in normotensive subjects. For this purpose, eight subjects received an intrabrachial artery infusion of regular insulin at a systemically ineffective rate (0.05 milliunits/kg per minute) so that deep-venous insulin levels increased in the experimental forearm from 16.5 +/- 2.9 to 379.6 +/- 30 pmol/L (p < 0.01), whereas arterial insulin levels remained unchanged (from 40.9 +/- 8.6 to 43.1 +/- 7.9 pmol/L, NS). In the control arm, forearm vascular resistance (units) increased from 52.3 +/- 3 to a peak of 78.4 +/- 5 (p < 0.001) during lower body negative pressure. In the insulin-exposed forearm, vascular resistance (46.4 +/- 2 at baseline) remained unchanged during insulin infusion (45.8 +/- 3, NS) and rose to a peak of 54.8 +/- 6 (p < 0.05) during lower body negative pressure. The response of forearm vascular resistance to lower body negative pressure was different in the two forearms (F = 4.506, p < 0.01, repeated-measures analysis of variance with grouping factor). Our results demonstrate that in normotensive subjects local physiological hyperinsulinemia reduces the forearm vasoconstrictive response to reflex sympathetic activation.

Adult↗
PubMed1993

Influence of hypercholesterolemia on adrenal steroid metabolism and electrolyte balance in spontaneously hypertensive rats.

Hypercholesterolemia and hypertension are frequently associated risk factors for cardiovascular diseases. The interactions between hypercholesterolemia and the regulatory mechanisms of blood pressure are poorly understood. In this study we investigated the effects of hypercholesterolemia on salt metabolism and its hormonal control mechanisms in spontaneously hypertensive rats (SHR). Six-week-old SHR were randomly assigned to either a high (1%) cholesterol diet or a matched regular diet for 6 weeks, followed by a 2-week dietary washout. A group of normotensive Wistar-Kyoto rats received the high cholesterol diet and was used as a control. Plasma cholesterol increased significantly (P < 0.001) in both cholesterol-fed SHR and Wistar-Kyoto rats. Blood pressure was unaffected by 6 weeks of a high cholesterol diet. Hypercholesterolemia caused a significant increase in aldosterone (by analysis of variance: F = 8.40; P < 0.01) associated with a significant decrease in corticosterone (F = 4.64; P < 0.05) in the SHR, but not in the normotensive rats. In addition, in the cholesterol-fed SHR, urinary sodium excretion was reduced (P < 0.01), and the urinary potassium/sodium ratio was increased (P < 0.01) compared to those in the remaining groups of rats. The hormonal and urinary differences between the hypertensive subgroups were not detectable after withdrawal of cholesterol. These results demonstrate that diet-induced hypercholesterolemia specifically promotes reversible mineralocorticoid accumulation and sodium retention in SHR.

Adrenal Cortex Hormones↗
PubMed1993

Effects of angiotensin converting enzyme inhibitors on left ventricular hypertrophy.

It is well known that, in patients with essential hypertension, left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular disease. However, it has been demonstrated that normalisation of arterial pressure, by therapy with antihypertensive drugs, is associated with regression of LVH, although the extent and time-course of this phenomenon depend on the antihypertensive drug used. In particular, angiotensin converting enzyme (ACE) inhibitors seem capable of inducing a faster and more complete reversal of LVH in patients with essential hypertension than other antihypertensive drugs. The mechanisms underlying this property of ACE inhibitors remain unclear, although 2 features of ACE inhibitors may be particularly relevant. The first is their ability to improve large artery compliance, this being a major determinant of LVH. Arterial compliance is reduced in essential hypertension, resulting in increased left ventricular end-systolic stress, which then contributes to the development of LVH. The second possible mechanism by which ACE inhibitors reverse LVH to a greater degree than other antihypertensive drugs may relate to their ability to interfere with the cardiopulmonary receptor control of the circulation. Thus, ACE inhibitors may counteract the neural and hormonal abnormalities that contribute to the maintenance of LVH in hypertensive patients.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

[The practical aspects of treatment in heart failure].

Congestive heart failure (CHF) has been treated for several years on empiric basis, until the results of the major clinical trials have made possible a pathophysiological approach to the treatment of patients with CHF. Studies from our laboratories have demonstrated that hemodynamic and neurohormonal responses to acute volume expansion are markedly impaired in patients with dilated cardiomyopathy and mild heart failure (NYHA Class I) and that pretreatment with ACE-inhibitors is able to prevent these abnormal responses. New insights into a more pathophysiological approach to CHF treatment are now possible by the development of new noninvasive techniques for the study of cardiac function. In particular, through radionuclide techniques we were able to demonstrate that patients with CHF show an exercise induced hemodynamic response different from that of normal subjects. Both ACE-inhibitors and digitalis were able to restore a normal response to exercise in patients with CHF.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Left ventricular systolic and diastolic function measurements using an ambulatory radionuclide monitor: effects of different time averaging on accuracy.

The accuracy of an ambulatory radionuclide detector (VEST) for left ventricular systolic (ejection fraction, EF) and diastolic (peak filling rate, PFR) measurements was assessed at different time averaging of the nuclear and electrocardiographic data. Fifty-one patients, in a total of 67 studies, underwent equilibrium radionuclide angiography (RNA) immediately before a VEST study. VEST data were analyzed using single-beat analysis and different time averaging of 5, 10, 15, 30 and 60 sec. Agreement between VEST and RNA in estimating EF and PFR was evaluated by computing limits of agreement (LA). These were computed as 1.96 times the s.d. of the mean differences between the two methods, expressed in the same unit as EF and PFR. Differences between the two methods were plotted against their mean, allowing investigation of any possible relationship between measurement error and the true value (whose best estimate is the mean between the two methods). The entire statistical analysis was repeated at each different time averaging. LAs for EF measurement by VEST were -10.4:8.8 (single-beat analysis), -11.2:9.9 (5-sec averaging), -5.4:4.8 (10-sec averaging), -4.9:4.5 (15-sec averaging), -6.2:5.6 (30-sec averaging), -6.9:4.5 (60-sec averaging). Results indicate good agreement between VEST and RNA in measuring EF, at least for time averaging > or = 10 sec. LAs for PFR ranged from -0.6:0.6 (single beat) to -1.0:0.6 (60-sec averaging), which was considered a clinically acceptable agreement between VEST and RNA. No relationship between measurement error and true value was found either for EF and PFR.

Electrocardiography, Ambulatory↗
PubMed1993

Reverse redistribution in resting thallium-201 myocardial scintigraphy in patients with coronary artery disease: relation to coronary anatomy and ventricular function.

We studied 25 male patients, with coronary artery disease, mean age 56 +/- 8 yr. All underwent 201Tl rest-redistribution and resting 99mTc methoxyisobutyl isonitrile (MIBI) cardiac imaging. Regional 201Tl and MIBI uptake were quantitatively analyzed. Regional left ventricular wall motion (WM) was visually assessed on MIBI gated images using a three-point scale (0 = normal, 1 = hypokinetic, 2 = a/dyskinetic). Two patterns of reverse redistribution (RR) were identified: RR-A when 201Tl uptake was normal on rest images and abnormal on redistribution images, and RR-B when 201Tl uptake was abnormal on rest images and a significant decrease in uptake was observed on redistribution images. Of the total 375 myocardial segments analyzed, 229 were classified as normal (Nl), 40 as reversible defect (RD), 74 as irreversible defect (ID); 26 showed RR-A while 6 myocardial segments had RR-B. Myocardial segments with RR-A differed from NI in the degree of coronary artery stenosis (81% +/- 33% versus 57% +/- 39%, respectively, p < 0.05), in WM score (1.1 +/- 0.7 versus 0.5 +/- 0.6, respectively, p < 0.01), and in MIBI uptake (81% +/- 10% versus 92% +/- 9%, respectively, p < 0.0001). Moreover, the percent of myocardial segments supplied by a totally occluded coronary artery was significantly higher (p < 0.05) in myocardial segments with RR-A (46%) than in NI (22%). Segments with RR-B did not show any significant difference either from RD and ID. These results suggest that myocardial segments with RR-A on resting 201Tl images have impaired function and are supplied by severely stenosed coronary arteries and should not be considered normal.

Adult↗
PubMed1992

Reversal of cardiac and large artery structural abnormalities induced by long-term antihypertensive treatment with trandolapril.

In 15 patients with untreated mild to moderate essential hypertension and left ventricular hypertrophy, we assessed blood pressure, echocardiographic left ventricular mass index, brachial artery compliance (pulsed doppler flowmetry), and calculated forearm vascular resistance (strain gauge plethysmography) before, during (6 and 12 months) and after (1 month washout period) 1 year of satisfactory (blood pressure < or = 140/90 mm Hg) antihypertensive therapy with the angiotensin-converting enzyme inhibitor trandolapril (2.0 mg orally once daily). During the antihypertensive effective treatment, we observed a significant reduction of systolic and diastolic blood pressures, left ventricular mass index, and forearm vascular resistance at both 6 and 12 months. In addition, brachial artery compliance was significantly increased. After washout, systolic (156 +/- 3 mm Hg) and diastolic (102 +/- 1 mm Hg) blood pressures returned to levels comparable to baseline. However, left ventricular mass index (132 +/- 4; p < 0.01) and brachial artery compliance (1.53 +/- 0.01; p < 0.01) were still different from baseline. These results demonstrate that chronic antihypertensive treatment with trandolapril is associated with a stable regression of cardiac and vascular abnormalities, which is partially unrelated to the blood pressure lowering effect.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

Accuracy and repeatability of left ventricular systolic and diastolic function measurements using an ambulatory radionuclide monitor.

The accuracy and repeatability of a new ambulatory radionuclide detector (VEST) for left ventricular systolic (ejection fraction) and diastolic (peak filling rate) measurements were assessed. Seventeen patients underwent equilibrium radionuclide angiography immediately before and immediately after a VEST study. The accuracy was evaluated at the beginning and at the end of the VEST studies. Limits of agreement for the ejection fraction were -1%:2% at the beginning of the VEST study and -4%:4% at the end. Limits of agreement for the peak filling rate were -0.6:0.6 at the beginning of the VEST study and -0.7:0.5 at the end. For both measurements the limits of agreement were well within the clinical range. Repeatability was evaluated in a second group of 11 patients who underwent VEST studies in 2 separate days. The coefficient of repeatability (twice the standard deviation of the differences between the 2 studies) was 13 for the ejection fraction and 0.4 for the peak filling rate. Thus, the VEST is an accurate and repeatable method to measure both the ejection fraction and peak filling rate.

Coronary Disease↗
PubMed1992

Abnormal sympathetic overactivity evoked by insulin in the skeletal muscle of patients with essential hypertension.

The reason why hyperinsulinemia is associated with essential hypertension is not known. To test the hypothesis of a pathophysiologic link mediated by the sympathetic nervous system, we measured the changes in forearm norepinephrine release, by using the forearm perfusion technique in conjunction with the infusion of tritiated NE, in patients with essential hypertension and in normal subjects receiving insulin intravenously (1 mU/kg per min) while maintaining euglycemia. Hyperinsulinemia (50-60 microU/ml in the deep forearm vein) evoked a significant increase in forearm NE release in both groups of subjects. However, the response of hypertensives was threefold greater compared to that of normotensives (2.28 +/- 45 ng.liter-1.min-1 in hypertensives and 0.80 +/- 0.27 ng.liter-1 in normals; P less than 0.01). Forearm glucose uptake rose to 5.1 +/- .7 mg.liter-1.min-1 in response to insulin in hypertensives and to 7.9 +/- 1.3 mg.liter-1.min-1 in normotensives (P less than 0.05). To clarify whether insulin action was due to a direct effect on muscle NE metabolism, in another set of experiments insulin was infused locally into the brachial artery to expose only the forearm tissues to the same insulin levels as in the systemic studies. During local hyperinsulinemia, forearm NE release remained virtually unchanged both in hypertensive and in normal subjects. Furthermore, forearm glucose disposal was activated to a similar extent in both groups (5.0 +/- 0.6 and 5.2 +/- 1.1 mg.liter-1.min-1 in hypertensives and in normals, respectively). These data demonstrate that: (a) insulin evokes an abnormal muscle sympathetic overactivity in essential hypertension which is mediated by mechanisms involving the central nervous system; and (b) insulin resistance associated with hypertension is demonstrable in the skeletal muscle tissue only with systemic insulin administration which produces muscle sympathetic overactivity. The data fit the hypothesis that the sympathetic system mediates the pathophysiologic link between hyperinsulinemia and essential hypertension.

Adult↗
PubMed1992

[Ambulatory monitoring of left ventricular function: the assessment of transient episodes of ventricular dysfunction in patients with ischemic cardiopathy].

BACKGROUND: The recent development of an ambulatory radionuclide detector (VEST) to assess left ventricular (LV) function may enhance the detection of ischemia during routine daily activities in patients with coronary artery disease (CAD). The aim of this study was to evaluate the usefulness of VEST in monitoring LV ejection fraction (EF) responses to daily activities and sustained handgrip test (HG) in patients with CAD. METHODS: 13 patients (12 men and 1 woman) with angiographically proven coronary artery disease were studied by VEST (mean 162 min, range 120 to 250 min). LV responses to different daily activities (walking and climbing stairs) and to HG were evaluated. RESULTS: Walking on a level surface and climbing stairs did not induce significant change in mean LVEF. However, a transient decrease in EF was observed in 4 (31%) and in 5 (38%) of the 13 patients during walking and climbing stairs, respectively. HG induced a significant (p < 0.01) reduction in mean EF. In particular, during HG, EF decreased > or = 5% in 11 (85%) of the 13 patients. A transient spontaneous decrease in LVEF lasting > or = 1 min was observed on 18 occasions in 11 patients with CAD; 5 episodes were symptomatic and 13 asymptomatic. ECG ST segment depression was recorded in 4 of the 5 symptomatic and in 5 of the 13 asymptomatic episodes. CONCLUSIONS: These results suggest that simultaneous monitoring of LV function and ECG may permit a better understanding of the incidence and severity of ischemic symptomatic and asymptomatic episodes.

Aged↗
PubMed1992

Identification of viable myocardium in patients with chronic coronary artery disease: comparison of thallium-201 scintigraphy with reinjection and technetium-99m-methoxyisobutyl isonitrile.

We compared the results of 201Tl reinjection and those of 99mTc-methoxyisobutyl isonitrile (MIBI) in identifying viable myocardium in 20 male patients with angiographically proven coronary artery disease (CAD) and left ventricular dysfunction (ejection fraction 30% +/- 8%). All patients had irreversible defects on standard exercise-redistribution thallium imaging. Thallium was reinjected immediately after the redistribution study, and images were reacquired. The patients also underwent stress and rest 99mTc-MIBI myocardial scintigraphy (2-day protocol). A total of 300 myocardial regions were analyzed, of which 122 (41%) had irreversible thallium defects on redistribution images before reinjection. Of the 122 myocardial regions with irreversible defects on standard stress-redistribution thallium cardiac imaging, 65 (53%) did not change at reinjection and 57 (47%) demonstrated enhanced uptake of thallium after reinjection. Of the same 122 irreversible defects on stress-redistribution thallium, 100 (82%) appeared as fixed defects and 22 (18%) were reversible on 99mTc-MIBI myocardial scintigraphy. These data indicate that 201Tl cardiac imaging with rest reinjection is superior to 99mTc-MIBI myocardial scintigraphy in identifying viable myocardium in patients with chronic CAD, suggesting that regions with severe reduction of 99mTc-MIBI uptake both on stress and rest images may contain viable myocardium.

Adult↗