Management of myocardial infarction: the proper priorities.
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Angioplasty, Balloon, Coronary↗
Biomedical subjects
E Boersma
Publications and source records attributed to E Boersma.
Prediction of improvement of ventricular function after revascularization. 18F-fluorodeoxyglucose single-photon emission computed tomography vs low-dose dobutamine echocardiography.
AIMS: To compare assessment of myocardial flow and glucose metabolism by single-photon emission computed tomography (SPECT) with low-dose dobutamine echocardiography in predicting improvement in regional and global left ventricular function after coronary artery bypass grafting. METHODS AND RESULTS: Thirty patients with regional wall motion abnormalities (mean ejection fraction 32 +/- 19%) were studied with low-dose dobutamine echocardiography (5 and 10 micrograms. kg-1 min-1) and thallium-201/ 18F-fluorodeoxyglucose(FDG) SPECT prior to surgery. For comparative analysis, a 13-segment model was used. Postoperative improvement was predicted if the echocardiogram showed that wall motion abnormalities were reversible during the dobutamine infusion and there was normal perfusion or relatively increased FDG uptake in perfusion defects (mismatch) in dyssynergic segments on SPECT. After surgery, ventricular function was reassessed. An echocardiogram was taken at the 3 month follow-up with the patient at rest. Regional wall motion had improved in 62/168 (37%) revascularized segments. In predicting functional outcome, low-dose dobutamine echocardiography reached a sensitivity of 89% and a specificity of 82%, with a positive predictive value of 74% and a negative predictive value of 93%, whereas for thallium-201/FDG SPECT these values were 84%, 86%, 78% and 90%, respectively. In patients with more than two viable segments on either technique, the wall motion score index, a surrogate of global ventricular function, improved significantly. CONCLUSION: For the optimal prediction of functional outcome, combined assessment of flow and FDG imaging is needed. Both thallium-201/FDG SPECT and low-dose dobutamine echocardiography appear comparable and similarly accurate in predicting improvement of left ventricular function after surgical revascularization.
Analysis of Variance↗
The apical long-axis rather than the two-chamber view should be used in combination with the four-chamber view for accurate assessment of left ventricular volumes and function.
BACKGROUND: Most biplane methods for the echocardiographic calculation of left ventricular volumes assume orthogonality between paired views from the apical window. Our aim was to study the accuracy of biplane left ventricular volume calculations when either the apical two-chamber or long-axis views are combined with the four-chamber view. The left ventricular volumes calculated from three-dimensional echocardiographic data sets were used as a reference. Twenty-seven patients underwent precordial three-dimensional echocardiography using rotational acquisition of planes at 2-degree intervals, with ECG and respiratory gating. End-diastolic and end-systolic left ventricular volumes and ejection fraction on three-dimensional echocardiography were calculated by (1) Simpson's methods (3DS) at 3 mm short-axis slice thickness (reference method) and by (2) biplane ellipse from paired views using either apical four- and two-chamber views (BE-A) or apical four- and long-axis views (BE-B). Observer variabilities were studied by the standard error of the estimate % (SEE) in 19 patients for all methods. RESULTS: The spatial angles (mean +/- SD) between the apical two-chamber, long-axis and four-chamber views were 63.3 degrees +/- 19.7 and 99.1 degrees +/- 25.6, respectively. The mean +/- SD of end-diastolic and end-systolic left ventricular volumes (ml) and ejection fraction (%) by 3DS were 142.2 +/- 60.9, 91.8 +/- 59.6 and 39.6 +/- 17.5, while that by BE-A were 126.7 +/- 60.4, 84.0 +/- 57.9 and 39 +/- 17 and by BE-B were 134.3 +/- 62.4, 88.6 +/- 59.7 and 39.1 +/- 16.7, respectively. BE-B intra-observer (8.4, 6.7 and 3.5) and inter-observer (9.8, 11.5 and 5.4) SEE for end-diastolic and end-systolic left ventricular volumes (ml) and ejection fraction (%), respectively, were smaller than that for BE-A (10.8, 8.8 and 4.1 and 11.4, 14.7 and 6.1, respectively). There was excellent correlation between 3DS and BE-A (r = 0.99, 0.98 and 0.98) and BE-B (0.98, 0.98 and 0.98) for calculating end-diastolic and end-systolic left ventricular volume and ejection fractions, respectively. There were no significant differences between BE-A and BE-B with 3DS for end-diastolic and end-systolic left ventricular volume and ejection fraction calculations (P = 0.2, 0.3 and 0.4 and P = 0.5, 0.5 and 0.4, respectively). There were closer limits of agreement (mean +/- 2 SD) between 3DS and BE-B 7.9 +/- 18.8, 3.2 +/- 14.2 and 0.8 +/- 5.8 than that between 3DS and BE-A 15.5 +/- 19.6, 7.8 +/- 16.2 and 1.1 +/- 7.4 for calculating end-diastolic and end-systolic left ventricular volume and ejection fractions, respectively. CONCLUSION: Both apical two-chamber and apical long-axis views are not orthogonal to the apical four-chamber view. Observer variabilities of BE-B were smaller than that for BE-A. BE-A and BE-B have excellent correlation and non-significant differences with 3DS for left ventricular volume and ejection fraction calculations. There were closer limits of agreement between BE-B with 3DS for left ventricular volume and ejection fraction calculations than that between BE-A and 3DS. Therefore, we recommend the use of the apical long-axis rather than the two-chamber view in combination with the four-chamber view for accurate biplane left ventricular volume and ejection fraction calculations.
Adult↗
Hemodynamic changes, plasma catecholamine responses, and echocardiographically detected contractile reserve during two different dobutamine-infusion protocols.
We studied hemodynamic changes, catecholamine responses, and the occurrence of improved wall thickening by echocardiography during two different dobutamine-infusion protocols. Forty-three patients were studied by using a stepwise incremental dobutamine dose-infusion protocol (10-40 microg/kg/min, 3-min intervals); a subgroup of 11 patients also underwent a continuous dobutamine-infusion protocol (10 microg/kg/min for 12 min) in random order. No patient used beta-blockers. At 3-min intervals, blood pressure, heart rate, and plasma concentrations of dobutamine, epinephrine, and norepinephrine were measured. The echocardiographic improvement of wall thickening was analyzed only in paired protocols by visual assessment in left ventricular regions with normal wall motion at rest. The mean heart rate increased in the continuous and stepwise protocols from 73 to 99 and 74 to 132 beats/min. There was no significant change in blood pressure response between the two protocols. The mean plasma dobutamine concentrations during the continuous and stepwise protocols at 0, 3, 6, 9, and 12 min were 0/0; 31/38; 80/203; 106/448; and 120/692 ng/ml, respectively. In each patient, a response curve was constructed for the plasma dobutamine concentration versus heart rate. The heart rate increment and dobutamine concentration at which wall thickening was detected were similar with both protocols (14 +/- 5 vs. 12 +/- 7 beats/min) and (80 +/- 40 vs. 92 +/- 48 ng/ml; mean +/- SD). Wall thickening was noted in two of 11 patients between 0 and 3 min and 11 of 11 patients between 3 and 6 min in both protocols. Catecholamine responses during the continuous and stepwise protocols were epinephrine, 23 versus 28/28 versus 36, and norepinephrine 301 versus 323/347 versus 519. Only norepinephrine plasma concentrations increased significantly during the stepwise protocol. A 6-min dobutamine infusion was sufficient during both protocols to reach an adequate plasma dobutamine concentration, which induced a detectable increase of wall thickening in all patients. There is a significant differences between the two protocols with regard to the plasma catecholamine changes, so some of the hemodynamic effects during the stepwise dobutamine-infusion protocol may be mediated through release of endogenous catecholamines.
Adrenergic beta-Agonists↗
Contribution of asynchrony and nonuniformity to mechanical interaction in normal and stunned myocardium.
In anesthetized pigs, we investigated whether asynchrony (delta T) and nonuniformity (regional differences) in contractility (delta E) could describe the interaction between normal and stunned myocardium. Mechanical interaction was evaluated by regional postsystolic work (PSW) before and after production of stunning by a 5-min occlusion of the left circumflex coronary artery [LCX (LCX stunning)] and a subsequent 10-min occlusion of the left anterior descending coronary artery [LAD (LAD stunning)]. delta T and delta E were intensified by intracoronary (LAD) infusions of dobutamine. From regional end-systolic pressure-segment length relationships, systolic segment shortening (SS), end-systolic elastance (E), external work (EW), and PSW were determined. LCX stunning decreased SSLCX from 14 +/- 2 (mean +/- SE, n = 9) to 10 +/- 2% and ELCX from 103 +/- 25 to 52 +/- 7 mmHg/mm, whereas the LAD region was unaffected. EWLCX decreased from 165 +/- 16 to 138 +/- 20 mmHg.mm, whereas PSWLCX increased from -4 +/- 6 to 8 +/- 3 mmHg.mm. Additional LAD stunning reduced SSLAD from 16 +/- 2 to 9 +/- 3% and ELAD from 79 +/- 10 to 31 +/- 6 mmHg/mm, without affecting SSLCX and ELCX. In the normal myocardium, PSWLAD increased and PSWLCX decreased, but, during local LAD dobutamine infusions after stunning, both PSWLCX and PSWLAD increased. In normal myocardium, the changes in PSWLCX could be described by delta T (65 +/- 11%) and delta E (37 +/- 15%). After stunning of the LAD area, the contribution of delta E increased to 55 +/- 14% at the expense of delta T (37 +/- 15%). Similar contributions of delta E (54 +/- 13%) and delta T (57 +/- 13%) were found when both the LCX and LAD distribution areas were stunned. In normal myocardium, both delta T and delta E modulate mechanical interaction, with the contribution of delta T exceeding that of delta E. In stunned myocardium, both factors contribute, but the contribution shifts in favor of delta E.
Animals↗
Early thrombolytic treatment in acute myocardial infarction: reappraisal of the golden hour.
BACKGROUND: There is conclusive evidence from clinical trials that reduction of mortality by fibrinolytic therapy in acute myocardial infarction is related to the time elapsing between onset of symptoms and commencement of treatment. However, the exact pattern of this relation continues to be debated. This paper discusses whether or not appreciable additional gain can be achieved with very early treatment. METHODS: The relation between treatment delay and short-term mortality (up to 35 days) was evaluated using tabulated data from all randomised trials of at least 100 patients (n = 22; 50,246 patients) that compared fibrinolytic therapy with placebo or control, reported between 1983 and 1993. FINDINGS: Benefit of fibrinolytic therapy was 65 (SD 14), 37 (9), 26 (6) and 29 (5) lives saved per 1000 treated patients in the 0-1, 1-2, 2-3, and 3-6 h intervals, respectively. Proportional mortality reduction was significantly higher in patients treated within 2 h compared to those treated later (44% [95% CI 32, 53] vs 20% [15, 25]; p = 0.001). The relation between treatment delay and mortality reduction per 1000 treated patients was expressed significantly better by a non-linear (19.4-0.6x(+)29.3x-1) than a linear (34.7 - 1.6x) regression equation (p = 0.03). INTERPRETATION: The beneficial effect of fibrinolytic therapy is substantially higher in patients presenting within 2 h after symptom onset compared to those presenting later.
Animals↗
Accurate measurement of left ventricular ejection fraction by three-dimensional echocardiography. A comparison with radionuclide angiography.
BACKGROUND: Three-dimensional echocardiography is a promising technique for calculation of left ventricular ejection fraction, because it allows its measurement without geometric assumptions. However, few data exist that study its reproducibility and accuracy in patients. METHODS AND RESULTS: Twenty-five patients underwent radionuclide angiography and three-dimensional echocardiography that used the rotational technique (2 degrees interval and ECG and respiratory gating). Left ventricular volume and ejection fraction were calculated by use of Simpson's rule at a slice thickness of 3 mm. Analyses were performed to define the largest slice thickness required for accurate calculation of left ventricular volume and ejection fraction. Three-dimensional echocardiography showed excellent correlation with radionuclide angiography for calculation of left ventricular ejection fraction (mean +/- SD, 38.9 +/- 19.8 and 38.5 +/- 18.0, respectively; r = .99); their mean difference was not significant (0.03 +/- 0.17; P = .3), and they had a close limit of agreement (-0.385, 0.315). Intraobserver variability for radionuclide angiography and three-dimensional echocardiography was 4.2% and 2.6%, respectively, whereas interobserver variability was 6.2% and 5.3%, respectively. There was no significant difference between left ventricular volume and ejection fraction calculated at a slice thickness of 3 mm and that calculated at different slice thicknesses up to 24 mm. However, the standard deviation of the mean difference showed a stepwise increase, particularly at thicknesses > 15 mm. At a slice thickness of 15 mm, the probability of three-dimensional echocardiography to detect > or = 6% difference in ejection fraction was 80%. CONCLUSIONS: Three-dimensional echocardiography has excellent correlation with radionuclide angiography for calculation of left ventricular ejection fraction in patients and has an observer variability similar to that of radionuclide angiography. We recommend the use of a 15-mm-thick slice for accurate and rapid measurement of left ventricular volume and ejection fraction.
Adult↗
Reduction in thrombotic events with heparin-coated Palmaz-Schatz stents in normal porcine coronary arteries.
BACKGROUND: The use of stents improves the result after balloon coronary angioplasty. Thrombogenicity of stents is, however, a concern. In the present study, we compared stents with an antithrombotic coating with regular stents. METHODS AND RESULTS: Regular stents were placed in coronary arteries of pigs receiving no aspirin (group 1; n = 8) or aspirin over 4 weeks (group 2, n = 10) or 12 weeks (group 3, n = 9). Stents coated with heparin (antithrombin III uptake, 5 pmol/stent) were placed in 7 pigs that did not receive aspirin (group 4). The other animals received aspirin and coated stents with a heparin activity of 12 pmol antithrombin III/stent (group 5, n = 10) or 20 pmol/stent (group 6, n = 10; group 7, n = 10). Quantitative arteriography was performed at implantation and after 4 (groups 1, 2, and 4 through 6) or 12 weeks (groups 3 and 7). In an additional 5 animals, five regular and five coated stents (20 pmol/stent) were placed and explanted after 5 days for examination of the early responses to the implants. Thrombotic occlusion of the regular stent occurred in 9 of 27 in groups 1 through 3. However, in 0 of 30 of the animals receiving high-activity heparin-coated stents (groups 5 through 7), thrombotic stent occlusion was observed (P < .001). Histological analysis at 4 weeks showed that the neointima in group 6 was thicker compared with its control group 2 (259 +/- 104 and 117 +/- 36 microns, P < .01), but at 12 weeks the thickness was similar (152 +/- 61 and 198 +/- 49 microns, respectively). Comparison at 5 days suggested delayed endothelialization of the coating. CONCLUSIONS: High-activity heparin coating of stents eliminates subacute thrombosis in porcine coronary arteries.
Angioplasty, Balloon, Coronary↗
Inter- and intra-observer variability in the qualitative categorization of coronary angiograms.
The ABC classification of the American College of Cardiology and the American Heart Association is a commonly used categorization to estimate the risk and success of intracoronary intervention, as well as the probability of restenosis. To evaluate the reliability of qualitative angiogram readings, we randomly selected 200 films from single lesion angioplasty procedures. A repeated visual assessment (> or = 2 months interval) by two independent observers resulted in kappa values of inter and intra-observer variability for the ABC lesion classification and for all separate items that compile it. Variability in assessment is expressed in percentage of total agreement, and in kappa value, which is a parameter of the agreement between two or more observations in excess of the chance agreement. Percentage of total agreement and kappa value was 67.8% and 0.33 respectively for the ABC classification, indicating a poor agreement. Probably this is due to the deficiency of strict definitions. Further investigation has to demonstrate whether improvement can be achieved using complete and detailed definitions without ambiguity, and consensus after panel assessment.
Coronary Angiography↗
Initial results of combined anterior mitral leaflet extension and myectomy in patients with obstructive hypertrophic cardiomyopathy.
OBJECTIVES: The purpose of this study was to describe the clinical and functional results of combined anterior mitral leaflet extension and myectomy in patients with hypertrophic obstructive cardiomyopathy. BACKGROUND: Septal myectomy is the most commonly performed surgical procedure in patients with hypertrophic cardiomyopathy and left ventricular outflow tract obstruction. Because of the role of the mitral valve in creating the outflow tract gradient, mitral valve replacement or plication is performed in selected cases in combination with myectomy, often with better hemodynamic results than those of myectomy alone. Mitral valve leaflet extension, in which a glutaraldehyde-preserved autologous pericardial patch is used to enlarge the mitral valve along its horizontal axis, is a novel surgical approach in patients with hypertrophic obstructive cardiomyopathy. METHODS: Eight patients with hypertrophic obstructive cardiomyopathy were treated with mitral leaflet extension and myectomy. Preoperative and postoperative data (New York Heart Association functional class, number of drugs prescribed, width of the interventricular septum, severity of mitral valve regurgitation severity of systolic anterior motion of the mitral valve and outflow tract gradient) were compared with those of 12 patients undergoing myectomy alone. RESULTS: Preoperative evaluation demonstrated that mitral regurgitation and systolic anterior motion of the mitral valve were more severe in the group undergoing mitral valve extension (p < 0.001 and p < 0.05, respectively). There were no deaths associated with either surgical procedure. Two patients, both treated by myectomy alone, died during the follow-up period. Postoperatively, patients treated with mitral valve extension had less mitral regurgitation (p < 0.005), less residual systolic anterior motion (p < 0.001), greater improvement in functional class (p = 0.05) and greater reduction in the number of drugs (p < 0.005) and in septal thickness (p < 0.05). CONCLUSIONS: Mitral leaflet extension in combination with myectomy is a promising new surgical approach that may provide superior results to those of myectomy alone. Further studies are needed to determine the clinical value of this procedure.
Adult↗
Prediction of recovery of myocardial dysfunction after revascularization. Comparison of fluorine-18 fluorodeoxyglucose/thallium-201 SPECT, thallium-201 stress-reinjection SPECT and dobutamine echocardiography.
OBJECTIVES: We compared three techniques to predict functional recovery after revascularization. BACKGROUND: Recently, fluorine-18 (F-18) fluorodeoxyglucose in combination with single-photon emission computed tomography (SPECT) has been proposed to identify viable myocardium, Thallium-201 reinjection and low dose dobutamine echocardiography are used routinely for this purpose. METHODS: Seventeen patients (mean [+/- SD] left ventricular ejection fraction 36 +/- 11%) were studied. Regional and global ventricular function were evaluated before and 3 months after revascularization by echocardiography and radionuclide ventriculography, respectively. Myocardial F-18 fluorodeoxyglucose uptake (during hyperinsulinemic glucose clamping) was compared with rest perfusion assessed with early thallium-201 SPECT. On a separate day, low dose dobutamine echocardiography and post-stress thallium-201 reinjection SPECT were simultaneously performed. RESULTS: The sensitivities for F-18 fluorodeoxyglucose/thallium-201, thallium-201 reinjection and low dose dobutamine echocardiography to assess recovery were 89%, 93% and 85%, respectively; specificities were 77%, 43% and 63%, respectively. Stepwise logistic regression indicated that F-18 fluorodeoxyglucose/ thallium-201 was the best predictor. In hypokinetic segments, the combination of F-18 fluorodeoxyglucose/thallium-201 and low dose dobutamine echocardiography was the best predictor. Global function improved (left ventricular ejection fraction increased > 5%) in 6 patients and remained unchanged in 11. All three techniques correctly identified five of six patients with improvement. Fluorine-18 fluorodeoxyglucose/thallium-201 identified all patients without improvement; low dose dobutamine echocardiography identified 9 of 11 without improvement; and thallium-201 reinjection identified 6 of 11 patients without improvement. CONCLUSIONS: Fluorine-18 fluorodeoxyglucose/thallium-201 SPECT was superior to the other techniques in assessing functional recovery. Integration of metabolic and functional data is necessary, particularly in hypokinesia, for optimal prediction of improvement of regional function.
Adult↗
Low-dose dobutamine echocardiography and rest-redistribution thallium-201 tomography in the assessment of spontaneous recovery of left ventricular function after recent myocardial infarction.
Spontaneous improvement of contraction and perfusion occurs after acute myocardial infarction. The relative merit of low-dose dobutamine stress echocardiography (LDDE) and rest-redistribution thallium scintigraphy (RR TI) in this setting has not been evaluated. We studied 30 patients at 7 +/- 3 days after acute myocardial infarction with LDDE (5 to 10 micrograms/kg/min) and RR TI single photon emission computed tomography. Viability was defined as improvement of wall thickening at LDDE in the presence of redistribution or a defect with uptake > or = 50% of peak activity at RR TI. Baseline echocardiography and RR TI were repeated after 3 months. In 112 dyssynergic segments, viability was detected in 60 (54%) by RR TI and in 39 (35%) by LDDE (p < 0.005). Spontaneous improvement of function was detected in 35 (31 %) segments. In the same regions, thallium uptake increased significantly. The sensitivity, specificity, and accuracy of LDDE for predicting late improvement of wall motion were 77%, 84%, and 82%, respectively. Those of RR TI were 77%, 57%, and 63%, respectively. Specificity and accuracy of LDDE were higher than RR TI (p < 0.005). We conclude that a myocardial viability pattern after acute myocardial infarction is more frequently detected by RR TI than by LDDE. Both techniques are equally sensitive, but LDDE is a more specific predictor of spontaneous recovery of regional left ventricular function.
Adrenergic beta-Agonists↗
Implementation of a pre-hospital decision rule in general practice. Triage of patients with suspected myocardial infarction.
OBJECTIVE: To improve pre-hospital triage of patients with suspected acute cardiac disease. DESIGN: Prospective study. SUBJECTS. Patients with symptoms suggestive of acute cardiac pathology, who were seen by a general practitioner, for whom acute admission into hospital was requested, and in whom a pre-hospital electrocardiogram was recorded by the ambulance service. METHODS: The study consisted of two phases. In the first phase, a decision rule was developed based on clinical characteristics and electrocardiographic findings in 1005 patients with suspected acute cardiac pathology. In the second phase, the decision rule was prospectively validated. Symptoms were recorded by a standardized questionnaire by the general practitioner and a computerized electrocardiogram was made by the ambulance nurses at the patient's home. Three electrocardiographic outcomes were available: 'normal electrocardiogram', 'possible myocardial infarction' or 'extensive myocardial infarction'. By use of the predictive model, the general practitioner could decide if hospitalization was necessary or not. MAIN OUTCOME MEASUREMENTS: Identification of patients at low (stable angina, atypical chest pain, other pathology) and high (myocardial infarction, unstable angina) probability of acute cardiac pathology. RESULTS: Among 977 patients with a complete pre-hospital evaluation in the validation phase of the study, the decision rule recommended 'no hospitalization' in 227 patients (23%). The general practitioner followed this advice in 44% of these patients. Although seven of them developed a non-Q wave myocardial infarction, no complications occurred in patients not admitted. In addition, the general practitioner did not hospitalize 19 (2%) of 750 patients for whom the decision rule recommended admission. Pre-hospital triage by the general practitioner resulted in a 12% (118 of 977 patients) reduction of the number of patients admitted to the Coronary Care Units. CONCLUSIONS: Pre-hospital triage by the general practitioner was facilitated using a standardized questionnaire and pre-hospital electrocardiography, and resulted in a reduction in the number of patients admitted to the Coronary Care Unit, and proved to be safe.
Aged↗
Intracoronary heparin delivery in humans. Acute feasibility and long-term results.
BACKGROUND: Inefficacy of systemic drug administration for restenosis prevention may partially relate to insufficient local drug concentration. This study aimed to evaluate the acute feasibility and long-term outcome of using an infusion-perfusion coil balloon, Dispatch. METHODS AND RESULTS: In 22 patients after balloon angioplasty, the coil balloon was studied for (1) feasibility of local heparin delivery, (2) symptoms and signs of ischemia during prolonged deployment compared with angioplasty balloon occlusion, (3) coronary pressure and flow distal to the inflated device, and (4) long-term clinical and angiographic results. During prolonged intracoronary deployment of the coil balloon (29 +/- 8 minutes), 5 of 22 patients developed mild chest pain versus 20 of 22 during angioplasty (275 +/- 283 seconds). Neither hemodynamic nor vectorcardiographic signs of ischemia were detected, in contrast to angioplasty balloon occlusion. Baseline flow across the coil balloon was 44 +/- 31 mL/min, increasing by a factor of 1.8 +/- 0.7 during pharmacologically induced hyperemia. A mean volume of 14.2 +/- 6.1 mL containing 1416 +/- 608 IU of heparin was infused locally at a pressure of 122 +/- 54 mm Hg. At 7 +/- 1-month follow-up, 1 asymptomatic patient had died, and of the remaining 21, 17 (81%) were asymptomatic. Angiographic follow-up was obtained in 15 of 21 patients (71%), including all 4 symptomatic patients. Mean minimal luminal diameter after the procedure was 2.16 +/- 0.49 mm and at follow-up, 1.89 +/- 0.45 mm, which corresponds to a restenosis rate (diameter stenosis > or = 50%) of 7% (1/15). CONCLUSIONS: Intracoronary use of the coil balloon after balloon angioplasty proved to be feasible and subjectively as well as objectively well tolerated during prolonged deployment by virtue of its perfusion properties. High volumes of heparin solution can be infused locally at very low pressure. No unfavorable clinical or angiographic long-term effects were observed.
Adult↗
Correlation of coronary stenosis by quantitative coronary arteriography with exercise echocardiography.
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Adult↗
Cardiac chronotropic responsiveness to beta-adrenoceptor stimulation is not reduced in the elderly.
OBJECTIVES: This study evaluated cardiac beta-adrenoceptor responsiveness in the elderly. BACKGROUND: The hypothesis of reduced cardiac beta-adrenoceptor responsiveness in the elderly is based on a smaller increase in heart rate after administration of isoproterenol, a nonselective beta 1- and beta 2-adrenoceptor agonist. By means of dobutamine-stress-echocardiography we were able to retest the hypothesis more accurately because dobutamine is a relatively selective beta 1-adrenoceptor agonist with weak beta 2- and alpha-adrenoceptor stimulant activity that prevents baroreflex-mediated changes in heart rate. METHODS: After administration of stepwise incremental infusions of dobutamine, we measured heart rate and blood pressure responses in 360 patients who had no beta-adrenergic blocking agent therapy and no side effects during the stress test. For each patient we calculated the dose of dobutamine required to increase heart rate by 50% of the maximal heart rate during the highest dose of dobutamine. RESULTS: No relation was found between age and sensitivity to dobutamine (n = 293). Power analysis revealed that this negative finding was not the result of inadequate sample size. In contrast to the prevailing hypothesis, an increased heart rate response to dobutamine was found even in a subgroup of "healthy" elderly subjects (i.e., those without concomitant disease or acute myocardial ischemia, n = 67) that was not related to changes in blood pressure during stress. However, in subjects with acute ischemia (n = 109), smokers (n = 151) or patients with a history of a previous myocardial infarction (n = 148), dobutamine sensitivity was reduced in the elderly despite a diminished change in systolic blood pressure with advanced age during dobutamine infusion. This phenomenon could be explained by a decrease in efferent cardiac baroreflex sensitivity, as has been observed during acute myocardial ischemia. There were no age-related differences in plasma concentrations of dobutamine. CONCLUSIONS: No evidence for reduced beta-adrenoceptor responsiveness to dobutamine was found in "healthy" elderly subjects.
Aged↗
Quantitative angiographic measurements of isolated left anterior descending coronary artery stenosis. Correlation with exercise echocardiography and technetium-99m 2-methoxy isobutyl isonitrile single-photon emission computed tomography.
OBJECTIVES: This study sought to assess the value of quantitative coronary arteriography in predicting an ischemic response at exercise echocardiography and technetium-99m 2-methoxy isobutyl isonitrile (mibi) single-photon emission computed tomography (SPECT) in patients with single-vessel disease of the left anterior descending coronary artery. BACKGROUND: The relation between severity of coronary stenosis and ischemic response to exercise echocardiography and perfusion scintigraphy in patients with single-vessel left anterior descending coronary artery disease is not well established. METHODS: Thirty-one patients without a previous myocardial infarction who had isolated stenosis of varying degrees in the proximal or midportion of the left anterior descending coronary artery were studied. Quantitative arteriographic analysis was used for measurements of percent diameter stenosis and minimal lumen diameter. Exercise-induced wall motion abnormalities by echocardiography and transient perfusion defects by mibi SPECT were considered a positive response. The analysis of sensitivity/specificity and receiver operating characteristic curves was applied to establish the diagnostic power of quantitative coronary arteriography to predict an ischemic response to exercise echocardiography and mibi SPECT: RESULTS: The "best" angiographic cutoff values for predicting a positive exercise echocardiographic and scintigraphic response were similar (diameter stenosis 52%, minimal lumen diameter 1.12 mm for echocardiography; diameter stenosis 49%, minimal lumen diameter 1.20 mm for SPECT). However, the sensitivity/specificity at the cross point was slightly higher (even if not statistically significant) for echocardiography than for SPECT, both for diameter stenosis (81% vs. 67%) and minimal lumen diameter (81% vs. 74%), suggesting that quantitative coronary arteriographic measurements are more closely related to echocardiographic than scintigraphic exercise test results. CONCLUSIONS: The functional significance of a proximal/mid-left anterior descending coronary artery stenosis measured by quantitative coronary arteriography is slightly better related to echocardiographic than scintigraphic markers of exercise-induced myocardial ischemia.
Coronary Angiography↗
Improved cardiac risk stratification in major vascular surgery with dobutamine-atropine stress echocardiography.
OBJECTIVES: This study sought to optimize preoperative cardiac risk stratification in a large group of consecutive candidates for vascular surgery by combining clinical risk assessment and semiquantitative dobutamine-atropine stress echocardiography. BACKGROUND: Dobutamine-atropine stress echocardiography has been used for the prediction of perioperative cardiac risk in a small group of patients scheduled for elective major vascular surgery on the basis of the presence or absence of stress-induced regional left ventricular wall motion abnormalities. METHODS: Clinical risk assessment and dobutamine-atropine stress echocardiography were performed in 302 consecutive patients presenting for major vascular surgery. The extent and severity of stress wall motion abnormalities and the heart rate at which they occurred, in addition to the presence of wall motion abnormalities at rest, were assessed. RESULTS: The absence of clinical risk factors (angina, diabetes, Q waves on the electrocardiogram, symptomatic ventricular tachyarrhythmias, age > 70 years) identified a low risk group of 100 patients with a 1% cardiac event rate (unstable angina). Dobutamine-atropine stress echocardiographic findings were positive in 72 patients. Twenty-seven patients had a perioperative cardiac event (cardiac death in 5, nonfatal infarction in 12, unstable angina pectoris in 10); all 27 patients had positive stress test results (positive predictive value 38%, negative predictive value 100%). The semiquantitative assessment of the extent and severity of ischemia did not provide additional prognostic information in patients with positive test results. In contrast, the heart rate at which ischemia occurred defined a high risk group with a low ischemic threshold (38 patients with 20 events [53%]) and an intermediate risk group with a high ischemic threshold (34 patients with 7 events [21%]). All 5 patients with a fatal outcome and 8 of 12 with a nonfatal myocardial infarction were in the high risk group with a low ischemic threshold. CONCLUSIONS: Clinical variables identify 33% of patients at very low risk for perioperative complications of vascular surgery in whom further testing is redundant. In all other candidates, dobutamine-atropine stress echocardiography is a powerful tool that identifies those patients at intermediate risk and a small group at very high risk. Risk stratification with a combination of clinical assessment and pharmacologic stress echocardiography has the potential to facilitate clinical decision making and conserve resources.
Adult↗