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T F Christian

Publications and source records attributed to T F Christian.

At least 55 records · Page 3Linked to original sources
PubMed1995

Infarct size after acute myocardial infarction measured by quantitative tomographic 99mTc sestamibi imaging predicts subsequent mortality.

BACKGROUND: 99mTc sestamibi is a recently developed radioisotope that has been used to measure myocardium at risk and infarct size. The relation between these measurements and subsequent patient outcome has not yet been demonstrated. METHODS AND RESULTS: Two hundred seventy-four consecutive patients with acute myocardial infarction underwent tomographic 99mTc sestamibi imaging on arrival at the hospital (to measure myocardium at risk before reperfusion therapy) and at hospital discharge (to measure the amount of salvaged myocardium and final infarct size). Defect size on the sestamibi images was quantified using a threshold value of 60% of peak counts from the circumferential count profile curves generated for five representative slices of the left ventricle. Patients were followed after hospital discharge to evaluate the association between final infarct size and subsequent mortality. The median defect size measured was 27% of the left ventricle at presentation to the hospital (range, 0% to 77%) and was 12% of the left ventricle at hospital discharge (range, 0% to 68%). Almost one half of the patients had a final infarct size of < or = 10%. The median amount of myocardium salvaged was 9% (range, -31% to 75%). During a median duration of follow-up of 12 months, there were 10 deaths (7 cardiac and 3 noncardiac) and 1 resuscitated out-of-hospital cardiac arrest. There was a significant association between infarct size and overall mortality (chi 2 = 8.66, P = .003) and cardiac mortality (chi 2 = 11.89, P < .001). Two-year mortality was 7% for patients whose infarct size was > or = 12% versus 0% for patients whose infarct size was < 12%. There also was a significant association between myocardium at risk and cardiac mortality (chi 2 = 6.87, P = .009). There was no association between myocardium at risk and overall mortality or between amount of myocardium salvaged and either overall mortality or cardiac mortality. CONCLUSIONS: Larger infarct size measured by 99mTc sestamibi imaging after acute myocardial infarction is associated with increased mortality risk during short-term follow-up.

Aged↗
PubMed1995

Relation of initial infarct size to extent of left ventricular remodeling in the year after acute myocardial infarction.

OBJECTIVES: This study attempted to determine the relation between infarct size after acute myocardial infarction and subsequent left ventricular remodeling using precise clinical measurements. BACKGROUND: Animal studies have demonstrated that the degree of left ventricular remodeling after myocardial infarction is linearly related to infarct size. Clinical studies have not clearly replicated these results because of imprecise measurements and failure to adjust for patency of the infarct-related artery. METHODS: Infarct size was measured from technetium-99m (Tc-99m) sestamibi perfusion images in 14 patients (12 with an anterior, 2 with an inferior infarction) by a threshold method previously described and expressed as percent of the left ventricle (32 +/- 17% left ventricle [mean +/- SD], range 6% to 58%). Absolute end-systolic volume, end-diastolic volume and ejection fraction were determined by electron beam computed tomographic images performed at discharge and at 6 weeks, 6 months and 1 year after myocardial infarction. All patients had documented infarct-related artery patency after reperfusion therapy. RESULTS: At hospital discharge, there was no correlation between infarct size and end-systolic and end-diastolic volumes or ejection fraction. There was significant left ventricular dilation in the study group over the next year. As remodeling progressed, there was closer correlation between infarct size and ejection fraction and end-systolic volume measures (infarct size vs. end-systolic volume, from r = 0.43 at discharge to r = 0.80 at 1 year; infarct size vs. ejection fraction, from r = -0.39 at discharge to r = -0.84 at 1 year). There was a strong inverse correlation between infarct size at discharge and subsequent changes over the next year in end-systolic volume (r = 0.63, p = 0.02) and ejection fraction (r = -0.66, p = 0.01). CONCLUSION: Infarct size as measured by Tc-99m sestamibi at hospital discharge after an index infarction is predictive of subsequent change in left ventricular volume and function in the year after myocardial infarction. Patients with a large infarct demonstrated the greatest degree of dilation in the setting of patency of the infarct-related artery.

Adult↗
PubMed1995

Limited prognostic value of thallium-201 exercise treadmill testing early after myocardial infarction in patients treated with thrombolysis.

The purpose of this study was to determine the prognostic value of thallium-201 exercise treadmill testing performed early after myocardial infarction in patients treated with thrombolysis. A retrospectively identified group of 210 patients treated with thrombolytic therapy alone (n = 131) or with thrombolytic therapy and coronary angioplasty (n = 79) who underwent tomographic thallium exercise treadmill testing 9 +/- 6 days after infarction were followed up for a median of 21 months. There was a high prevalence of abnormalities on the thallium studies. One hundred thirty-nine (66%) patients had a high-risk scan, defined as redistribution in at least one segment, a defect outside the infarct zone, or increased pulmonary uptake. Thirty-six (17%) patients underwent early revascularization. In the remaining 174 patients, there were 30 initial cardiac events (1 cardiac death, 11 nonfatal recurrent myocardial infarctions, and 18 revascularization procedures performed > 3 months after the thallium study). No single exercise or thallium variable was predictive of outcome. At 2 years there were no differences in survival free of any cardiac event for patients with a high- or low-risk thallium scan treated with thrombolysis alone (high-risk scan 86% and low-risk scan 80%; p not statistically significant [NS]) or with both thrombolysis and coronary angioplasty (high-risk scan 80% and low-risk scan 77%; p NS). Postinfarction exercise thallium variables associated with poor outcome in the prethrombolytic era were not associated with an adverse outcome in patients who had been treated with thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Estimates of myocardium at risk and collateral flow in acute myocardial infarction using electrocardiographic indexes with comparison to radionuclide and angiographic measures.

OBJECTIVES: This study sought to determine the accuracy of the initial 12-lead electrocardiogram (ECG) in predicting final infarct size after direct coronary angioplasty for myocardial infarction and to examine which physiologic variables known to be determinants of outcome the ST segment changes most closely reflect. BACKGROUND: Myocardium at risk, collateral flow and time to reperfusion have been shown to be independent physiologic predictors of infarct size in animal and clinical models. However, such measurements may be difficult to perform on a routine basis in patients with myocardial infarction. The standard 12-lead ECG is inexpensive and readily available. METHODS: Sixty-seven patients with acute myocardial infarction, ST segment elevation and duration of chest pain < 12 h had an initial injection of technetium-99m sestamibi. Tomographic imaging was performed 1 to 8 h later (after direct coronary angioplasty), and the images were quantified to measure perfusion defect size (myocardium at risk) and severity (a measure of collateral flow). Contrast agent injection and tomographic acquisition were repeated at hospital discharge to measure infarct size. The ST segment elevation score was calculated for each patient according to infarct location and using previously described formulas. RESULTS: ST segment elevation score correlated closest with the radionuclide measure of collateral flow (r = -0.44, p < or = 0.0001), as well as an angiographic measure of collateral flow (r = -0.38, p = 0.05). Although ST segment elevation score correlated weakly with the magnitude of myocardium at risk by technetium-99m sestamibi, it was not as strong as infarct location alone in predicting myocardium at risk ([mean +/- SD] anterior 51 +/- 13% left ventricle vs. inferior 17 +/- 10% left ventricle, p < 0.0001). ST segment elevation score was weakly associated with final infarct size (r = 0.34, p = 0.005). A multivariate ECG model was constructed with infarct location as a surrogate for myocardium at risk, ST segment elevation score as a surrogate for estimated collateral flow, and elapsed time to reperfusion from onset of chest pain. All three variables were independently associated with infarct size. CONCLUSIONS: The initial standard 12-lead ECG can provide insight into myocardium at risk and, to a greater extent, collateral flow and can consequently provide some estimate of subsequent infarct size. However, the confidence limits for such predictors are wide.

Adult↗
PubMed1995

Effects of scatter correction on the measurement of infarct size from SPECT cardiac phantom studies.

UNLABELLED: Thallium-201 and 99mTc-sestamibi images of the heart contain a significant amount of scattered events which degrade image quality. Newer generation gamma cameras exhibit enhanced energy resolution and hardware/software to perform scatter correction. The principal aim of this study was to evaluate the effects of these advances in instrumentation on the quantitation of defect size from tomographic images of the heart obtained from a cardiac phantom. METHODS: Tomographic images of a cardiac phantom containing no defect and defects of 5%-70% of total myocardial mass were acquired both with and without scatter correction for 201Tl and 99mTc studies. Data were acquired on a newer generation gamma camera with an energy resolution of 8.7% at 140 keV. From conventional short-axis slices of the heart, circumferential count profiles were generated from five representative slices. Defect size was computed from the fraction of radians that fell below a fixed threshold value in each of the five count profiles. The nadir value (min/max) of the count profiles in each study was used as an index of image contrast. RESULTS: For both 201Tl and 99mTc, threshold values between 55%-60% gave the best correlation (r > 0.99), with the lowest average absolute error in estimating defect size (< 2.1%). Scatter correction reduced the average absolute error to 0.8% for 99mTc and 1.4% for 201Tl, significantly reduced the nadir values for both isotopes (p < 0.0001 for both 201Tl and 99mTc and led to a marked improvement in image quality for both tracers. CONCLUSION: Scatter correction reduces the error associated with measurement of infarct size, increases image contrast and improves image quality for both 201Tl and 99mTc, as assessed in a phantom model.

Gamma Cameras↗
PubMed1994

Exercise tomographic thallium-201 imaging in patients with severe coronary artery disease and normal electrocardiograms.

OBJECTIVE: To assess the incremental value and cost-effectiveness of exercise tomographic thallium-201 imaging compared with clinical and exercise electrocardiographic variables for detecting three-vessel or left main coronary artery disease in patients with normal at-rest electrocardiograms. DESIGN: Prospective cohort study. PARTICIPANTS: 411 patients (77 [19%] had three-vessel or left main disease) with normal at-rest electrocardiograms who underwent exercise tomographic thallium-201 studies and subsequently had coronary angiography. MEASUREMENTS: Clinical, exercise, and thallium-201 variables; univariate followed by multivariate logistic regression analysis to determine predictors of three-vessel or left main disease (clinical variables; clinical and exercise electrocardiographic variables; and clinical, exercise, and thallium-201 variables). Patients were classified by each of these models into low-, intermediate-, and high-risk groups. SETTING: A tertiary referral center. RESULTS: Among the clinical variables, diabetes mellitus, sex, age, and typical angina were independently associated with severe coronary disease (46% of patients were correctly classified into low- or high-risk groups). The peak exercise heart rate-blood pressure product and the magnitude of the exercise-induced ST depression added independent information to clinical variables. Among the thallium variables, the change in the global thallium-201 score (a measure of redistribution) added independent information to clinical and exercise variables, resulting in only 3% of the patients being reclassified regarding their predicted risk for severe coronary disease. The cost per additional reclassification was estimated to be $20,550. Twenty-one cardiac events occurred (7 cardiac deaths and 14 myocardial infarctions) after thallium study (follow-up, 2.8 +/- 1.0 years). Event-free survival was 94% to 97% regardless of the predicted probability of developing three-vessel or left main coronary artery disease by any model. CONCLUSIONS: When the at-rest electrocardiogram is normal, thallium-201 scintigraphy adds little information to clinical and exercise variables in identifying patients with severe coronary artery disease. The high cost of this information may not justify the routine use of sophisticated imaging for this purpose.

Coronary Angiography↗
PubMed1994

Myocardium at risk and infarct size after thrombolytic therapy for acute myocardial infarction: implications for the design of randomized trials of acute intervention.

OBJECTIVES: The purpose of this study was to estimate the effect of an improved reperfusion therapy for acute myocardial infarction on myocardial salvage and ventricular function for anterior and inferior infarctions and to ascertain the sample size required to detect such an effect. BACKGROUND: There are significant differences in myocardium at risk between anterior and inferior infarctions that affect the benefit of reperfusion therapy. METHODS: We studied 58 patients with acute myocardial infarction (24 anterior, 34 inferior) treated with intravenous recombinant tissue-type plasminogen activator and angioplasty when necessary. Tomographic imaging with technetium-99m sestamibi was performed to measure myocardium at risk, final infarct size and myocardial salvage and to estimate the beneficial effects of an improved therapy. RESULTS: A new therapy that was 30% more effective than existing therapy (with respect to salvage) would increase salvage (and reduce mean infarct size) by 5.2% of the left ventricle and increase late ejection fraction by only 0.012 (95% confidence interval [CI] 0.009 to 0.015) in inferior infarction and by 0.038 (95% CI 0.027 to 0.047) in anterior infarction. If anterior and inferior infarctions occurred with equal frequency, a sample size of 140 patients in each treatment group would be required to detect such a change with 80% power. In a trial of interior infarctions alone, a sample size of 236 patients in each treatment group would be required compared with only 98 patients in a trial of anterior infarctions alone. CONCLUSIONS: The anticipated mean benefit from an improved reperfusion therapy in individual patients with inferior infarction is very small and of questionable clinical significance. The anticipated benefit in anterior infarction is greater and easier to detect. Future randomized trials should be stratified for infarct location and should consider the greater absolute benefit of treatment in anterior infarction.

Adult↗
PubMed1994

Severe exercise-induced ischemia does not identify high risk patients with normal left ventricular function and one- or two-vessel coronary artery disease.

OBJECTIVES: This study was conducted to determine whether severe exercise-induced ischemia identifies high risk patients with a normal left ventricular ejection fraction and one- or two-vessel coronary artery disease. BACKGROUND: Severe ischemia during exercise radionuclide angiography has been shown to identify high risk patients among certain other patient subsets. METHODS: Four hundred twenty patients with left ventricular ejection fraction > or = 50% and one- or two-vessel disease underwent exercise radionuclide angiography within 3 months of coronary angiography. Patients were treated initially with revascularization (n = 140) or medical therapy (n = 280) at the discretion of their physicians. Patients treated with revascularization were more likely to have angina by history, a positive exercise electrocardiogram, a lower exercise ejection fraction, two-vessel disease and proximal left anterior descending coronary artery disease. Two hundred sixty-four of the 280 patients given medical therapy who had complete follow-up data formed the study group. Outcome was compared between patients with (n = 56) and without (n = 208) severe exercise-induced ischemia, defined by previously published criteria (work load < or = 600 kg-m/min, ST segment depression > or = 1 mm and decrease in ejection fraction with exercise). RESULTS: During follow-up, there were 30 initial cardiac events (12 cardiac deaths and 18 nonfatal myocardial infarctions). There was no difference in the 5-year event-free survival rate: 91% in patients with and 87% in patients without severe ischemia (p = 0.89). There was no association between event-free survival and severe ischemia (chi 2 = 1.41, p = 0.24). The study had approximately 80% power at alpha = 0.05 to detect a 25% decrease in event-free survival in the group with severe ischemia. In addition, there was no association between severe ischemia and outcome if late revascularization was included as an event or if the total mortality rate (overall survival) was analyzed. CONCLUSIONS: Severe exercise-induced ischemia fails to identify a high risk subgroup among patients with normal left ventricular function and one- or two-vessel disease who are treated initially with medical therapy.

Coronary Angiography↗
PubMed1994

Impaired left ventricular function, one- or two-vessel coronary artery disease, and severe ischemia: outcome with medical therapy versus revascularization.

OBJECTIVE: To determine whether patients with impaired left ventricular function and one- or two-vessel coronary artery disease who manifest severe ischemia during exercise radionuclide angiography have a lower rate of subsequent cardiac events when initial management is revascularization rather than medical therapy. DESIGN: During a median follow-up of 100 months, we compared the outcome between 37 patients who underwent a revascularization procedure and 22 who received medical therapy at the Mayo Clinic between September 1980 and December 1985. MATERIAL AND METHODS: The revascularization therapy consisted of coronary artery bypass grafting in 31 patients and coronary angioplasty in 6. Overall survival and survival free of initial cardiac events were compared statistically for the medically and surgically treated patients. RESULTS: Eleven deaths occurred in the patients who received medical therapy and 9 in the revascularization group. Five-year overall survival was 58% in the medically treated patients versus 84% in the revascularization group. A significant association was noted between type of treatment and overall survival (adjusted chi 2 = 6.20; P = 0.013). Twenty patients had initial cardiac events--7 in the medically treated group (3 cardiac deaths and 4 nonfatal myocardial infarctions) and 13 in the revascularization group (3 cardiac deaths, 3 out-of-hospital cardiac arrests, and 7 nonfatal myocardial infarctions). Survival free of cardiac events at 5 years was 72% in the medically treated patients and 66% in those who underwent revascularization. No association was detected between type of treatment and survival free of cardiac events. CONCLUSION: These nonrandomized data suggest that overall survival for patients with one- or two-vessel coronary artery disease, impaired left ventricular function, and severe exercise-induced ischemia may be improved by revascularization, but the subsequent cardiac event rates are not.

Aged↗
PubMed1994

Myocardial perfusion imaging in myocardial infarction and unstable angina.

The role of radionuclide perfusion imaging during acute coronary syndromes are discussed. The development of Tc-99m sestamibi has provided for significant advances in this field. This radionuclide enables a measurement of myocardium at risk and final infarct size and, consequently, myocardial salvage during reperfusion therapy. Analysis of acute images during infarction also allows for a measure of collateral flow to the infarct zone. This agent also can be used to triage patients with spontaneous chest pain suggestive of unstable angina.

Angina, Unstable↗
PubMed1993

Severity and response of chest pain during thrombolytic therapy for acute myocardial infarction: a useful indicator of myocardial salvage and infarct size.

OBJECTIVES: The purpose of this study was to determine noninvasively whether chest pain severity is predictive of the amount of myocardium at risk and whether the response of pain during thrombolysis is associated with myocardial salvage during acute myocardial infarction. BACKGROUND: The perception of chest pain and response to reperfusion therapy during acute myocardial infarction may provide important information for treatment benefit. Previous studies have been limited by the inability to measure myocardium at risk and myocardial salvage. METHODS: Sixty-two patients with acute myocardial infarction received an injection of technetium-99m sestamibi before thrombolysis and again at hospital discharge. Tomographic imaging was performed 1 to 6 h later. Myocardium at risk, infarct size and absolute myocardial salvage were derived from these images using previously described techniques and were expressed as a percent of the left ventricle. Salvage index was calculated by dividing myocardial salvage by the myocardium at risk. Chest pain severity was graded before thrombolysis as none, mild, moderate or severe. Chest pain response during thrombolytic therapy was graded as none, partial or completely resolved. RESULTS: There was no association between chest pain severity and myocardium at risk, but there was a weak trend toward greater myocardial salvage and salvage index (p = 0.09 and p = 0.12, respectively) for patients with more severe symptoms. Patients without chest pain at the start of thrombolysis still demonstrated significant salvage (11 +/- 11% of the left ventricle, p = 0.009). There was a significant association between chest pain response to therapy and both myocardial salvage (p = 0.03) and salvage index (p = 0.01). By multivariate analysis, chest pain severity and response of chest pain during thrombolysis were significant independent predictors of myocardial salvage, salvage index and infarct size. Thrombolysis was most effective in the 20 patients (32%) with moderate or severe chest pain and complete resolution of symptoms during thrombolysis (salvage of 79% to 89% of the area at risk). In the remaining 32 patients with chest pain, salvage of the area at risk was only 32%. CONCLUSIONS: These findings suggest that the assessment of chest pain before and after thrombolytic therapy is a readily available, useful indicator of the efficacy of the therapy.

Adult↗
PubMed1993

The effect of systemic hypertension on exercise tomographic thallium-201 imaging in the absence of electrocardiographic left ventricular hypertrophy.

This study was designed to assess the effect of systemic hypertension on exercise thallium-201 imaging. The study group consisted of 38 patients with systemic hypertension who were compared with 68 normotensive patients. All patients had a low pretest likelihood of coronary artery disease to minimize the influence of selection bias. Patients with electrocardiographic evidence of left ventricular hypertrophy were excluded. Single-photon emission computed tomographic thallium-201 images were obtained immediately after exercise and 4 hours after exercise. Thallium tomographic images were assessed qualitatively by 14 short-axis segments and were grouped into three coronary distributions. Regional and global quantitative analysis was also performed by using a reference study group at low risk for coronary artery disease. The hypertensive group demonstrated higher resting systolic blood pressure (137 +/- 26 mm Hg vs 120 +/- 14 mm Hg in the normotensive group, p = 0.0002) immediately before exercise. There was no significant difference between hypertensive and normotensive groups in peak exercise systolic blood pressure (181 +/- 31 mm Hg vs 172 +/- mm Hg, p = NS). The normotensive group achieved a significantly higher peak exercise heart rate (162 +/- 18 vs 146 +/- 20 beats/min in the hypertensive group, p = 0.0001) and higher estimated oxygen uptake (11.0 +/- 3.4 vs 9.1 +/- 2.7 metabolic equivalents [METS] in the hypertensive group, p = 0.003). However, rate-pressure products for both groups were nearly identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Prognosis of myocardial infarctions involving more than 40% of the left ventricle after acute reperfusion therapy.

BACKGROUND: Prior studies based on autopsy data suggest that infarction of more than 40% of the left ventricle necessitates cardiogenic shock and death. METHODS AND RESULTS: Technetium-99m Sestamibi tomography was used prospectively to measure infarct size at discharge in 166 patients with acute myocardial infarction. Patients with previous myocardial infarction or revascularization were excluded from the trial. Sixteen patients were identified with final infarct sizes > 40% of the left ventricle despite acute reperfusion therapy. These 16 patients (13 men) had a mean age of 63 +/- 10 years; 44% had a previous history of angina. Ten patients had emergent coronary angioplasty only (mean time to percutaneous transluminal coronary angioplasty [PTCA], 6.0 +/- 3.0 hours); 6 had thrombolysis (mean time to tissue plasminogen activator, 4.0 +/- 1.5 hours), of which 2 had rescue PTCA (5 and 3 hours from onset of pain). Of 15 patients who had angiograms after therapy, 15 had open infarct-related arteries. The left anterior descending artery was the infarct-related artery in 14 (9 proximal and 5 distal lesions). Half the patients had only single-vessel disease. Infarct size measured 50 +/- 7% of the left ventricle (range, 42% to 68%). Ejection fraction by radionuclide angiogram was 0.33 +/- 0.09 and 0.38 +/- 0.07 at discharge and 6 weeks, respectively. Hospital complications included shock (1 patient), pulmonary edema (2), angina (3), symptomatic nonsustained ventricular tachycardia (1), transient complete heart block (2), and transient bifascicular block (1). At follow-up (13 +/- 9 months), the patient with shock had died, but the remaining 15 patients were asymptomatic (1 had late PTCA for angina). CONCLUSIONS: In the interventional and thrombolytic era, patients with large residual myocardial infarctions can survive without heart failure.

Angioplasty, Balloon, Coronary↗
PubMed1993

Residual flow to the infarct zone as a determinant of infarct size after direct angioplasty.

BACKGROUND: In acute myocardial infarction, residual flow to the infarct zone either through antegrade flow in the infarct-related coronary artery or collateral flow from the non-infarct-related arteries is often present before reperfusion therapy. The purpose of this study was to assess the influence of antegrade flow in the infarct-related artery and/or collateral flow to the infarct zone before successful direct angioplasty on infarct size and myocardial salvage in patients with acute evolving myocardial infarction. METHODS AND RESULTS: Sixty patients with acute evolving myocardial infarction underwent direct successful angioplasty without prior thrombolytic therapy. The myocardium at risk of infarction, the final infarct size, and myocardial salvage were measured by tomographic perfusion imaging with 99mTc sestamibi. Antegrade flow in the infarct-related artery before intervention was graded according to the Thrombolysis in Myocardial Infarction (TIMI) study group classification. Collateral flow to the infarct zone before angioplasty was also graded (0 through 3, 0 being no collateral flow). The presence of even minimal antegrade flow before angioplasty (TIMI grade 1) in the infarct-related artery compared with absent flow was associated with a significant reduction in final infarct size (9 +/- 17% versus 23 +/- 19% of left ventricle, P = .02) and a significant increase in myocardial salvage (23 +/- 16% versus 14 +/- 13% of left ventricle, P = .05) after angioplasty. When antegrade flow in the infarct-related artery was absent before angioplasty, the presence of collateral flow before angioplasty resulted in a significantly smaller final infarct size (P = .01) and more myocardial salvage (P = .05) after angioplasty. Both antegrade infarct-related artery flow and collateral flow to the infarct zone had significant independent ability to predict infarct size after angioplasty. When collateral grade and TIMI grade were added to provide an estimate of residual flow, a model including residual flow, myocardium at risk, and the interaction of residual flow and infarct site explained 83% of the variability in infarct size after angioplasty. CONCLUSIONS: The presence of antegrade flow in the infarct-related artery and/or collateral flow to the infarct zone before direct angioplasty in acute evolving infarction results in a smaller infarct size after direct successful angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1992

Prognosis with abnormal thallium images in the absence of significant coronary artery disease.

In the presence of coronary artery disease (CAD), thallium imaging has been reported to add prognostic information that is independent of coronary anatomy. To investigate the prognostic importance of thallium imaging in the absence of significant CAD, 87 patients (65 men, 22 women) with abnormal thallium images without significant CAD were followed for a median duration of 22 months (range 11 to 50). Tomographic thallium images obtained immediately and 4 hours after exercise were interpreted by 2 experienced observers who graded thallium uptake in 24 segments in 3 views (short axis, horizontal long axis, vertical long axis) on a 5-point scale (normal; mildly, moderately, or severely reduced; absent). All patients had an abnormal thallium study, defined as a reversible defect of at least mild severity or a fixed defect of at least moderate severity seen in > or = 2 views, or a combination of these, and a coronary angiogram with stenosis not > or = 70% in diameter narrowing. Eighty-two patients had at least 1 reversible segment, and 26 patients had defects in > or = 2 coronary artery distributions. During follow-up there were no deaths or myocardial infarctions. Coronary angioplasty and bypass surgery were performed in 2 patients. Three-year survival without myocardial infarction or revascularization was 97%. Patients with abnormal thallium images in the absence of significant CAD have an excellent short-term prognosis.

Adult↗