Salvador Borges-Neto

The economic consequences of available diagnostic and prognostic strategies for the evaluation of stable angina patients : An observational assessment of the value of precatheterization ischemia

OBJECTIVES The study aim was to determine observational differences in costs of care by the coronary disease diagnostic test modality. BACKGROUND A number of diagnostic strategies are available with few data to compare the cost implications of the initial test choice. METHODS We prospectively enrolled 11,372 consecutive stable angina patients who were referred for stress myocardial perfusion tomography or cardiac catheterization. Stress imaging patients were matched by their pretest clinical risk of coronary disease to a series of patients referred to cardiac catheterization. Composite 3-year costs of care were compared for two patients management strategies: 1) direct cardiac catheterization (aggressive) and 2) initial stress myocardial perfusion tomography and selective catheterization of high risk patients (conservative). Analysis of variance techniques were used to compare costs, adjusting for treatment propensity and pretest risk. RESULTS Observational comparisons of aggressive as compared with conservative testing strategies reveal that costs of care were higher for direct cardiac catheterization in all clinical risk subsets (range:

Quantification of myocardial infarction during coronary occlusion and myocardial salvage after reperfusion using cardiac imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile

2,878 to

Patient management after noninvasive cardiac imaging: Results from SPARC (Study of myocardial perfusion and coronary anatomy imaging roles in coronary artery disease)

4,579), as compared with stress myocardial perfusion imaging plus selective catheterization (range:

Myocardial perfusion changes in patients irradiated for left-sided breast cancer and correlation with coronary artery distribution

2,387 to

Cardiac perfusion changes in patients treated for breast cancer with radiation therapy and doxorubicin: preliminary results

3,010, p < 0.0001). Coronary revascularization rates were higher for low, intermediate and high risk direct catheterization patients as compared with the initial stress perfusion imaging cohort (13% to 50%, p < 0.0001); cardiac death or myocardial infarction rates were similar (p > 0.20). CONCLUSIONS Observational assessments reveal that stable chest pain patients who undergo a more aggressive diagnostic strategy have higher diagnostic costs and greater rates of intervention and follow-up costs. Cost differences may reflect a diminished necessity for resource consumption for patients with normal test results.

Prospective assessment of radiotherapy‐associated cardiac toxicity in breast cancer patients: Analysis of data 3 to 6 years after treatment

Myocardial imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile was investigated as a means to assess myocardial infarct size during coronary occlusion and to quantify the extent of salvaged myocardium after coronary occlusion followed by reperfusion. Open chest dogs underwent either a permanent coronary artery occlusion (Group 1, n = 16) or a 2 h occlusion followed by reperfusion (Group 2, n = 15). Animals in both groups were killed 48 h after occlusion. During coronary occlusion, 23 of the 25 dogs that survived the coronary occlusions had abnormal myocardial scintigrams. The scintigraphic perfusion defect size correlated well with the pathologic infarct size (r = 0.85 and 0.95 by planar and tomographic imaging, respectively). The planar scintigraphic defect size, but not the tomographic defect size, overestimated the pathologic size. The planar scintigraphic defect size observed during coronary occlusion was markedly reduced 48 h after reperfusion (24.8 +/- 12.8% to 10.6 +/- 9.7% of the left ventricle, p less than 0.003). The uptake of technetium-99m hexakis 2-methoxyisobutyl isonitrile in the ischemic myocardium increased significantly 48 h after reperfusion (p less than 0.003) and correlated with the increase in regional myocardial blood flow, as assessed by radioactive microspheres (r = 0.83, p less than 0.01). Thus, myocardial imaging with technetium-99m hexakis 2-methoxyisobutyl isonitrile allows reliable demonstration of the presence of acute infarction, estimation of infarct size and quantification of the extent of salvaged myocardium after coronary reperfusion.

Inducible myocardial ischemia and outcomes in patients with coronary artery disease and left ventricular dysfunction.

OBJECTIVES This study examined short-term cardiac catheterization rates and medication changes after cardiac imaging. BACKGROUND Noninvasive cardiac imaging is widely used in coronary artery disease, but its effects on subsequent patient management are unclear. METHODS We assessed the 90-day post-test rates of catheterization and medication changes in a prospective registry of 1,703 patients without a documented history of coronary artery disease and an intermediate to high likelihood of coronary artery disease undergoing cardiac single-photon emission computed tomography, positron emission tomography, or 64-slice coronary computed tomography angiography. RESULTS Baseline medication use was relatively infrequent. At 90 days, 9.6% of patients underwent catheterization. The rates of catheterization and medication changes increased in proportion to test abnormality findings. Among patients with the most severe test result findings, 38% to 61% were not referred to catheterization, 20% to 30% were not receiving aspirin, 35% to 44% were not receiving a beta-blocker, and 20% to 25% were not receiving a lipid-lowering agent at 90 days after the index test. Risk-adjusted analyses revealed that compared with stress single-photon emission computed tomography or positron emission tomography, changes in aspirin and lipid-lowering agent use was greater after computed tomography angiography, as was the 90-day catheterization referral rate in the setting of normal/nonobstructive and mildly abnormal test results. CONCLUSIONS Overall, noninvasive testing had only a modest impact on clinical management of patients referred for clinical testing. Although post-imaging use of cardiac catheterization and medical therapy increased in proportion to the degree of abnormality findings, the frequency of catheterization and medication change suggests possible undertreatment of higher risk patients. Patients were more likely to undergo cardiac catheterization after computed tomography angiography than after single-photon emission computed tomography or positron emission tomography after normal/nonobstructive and mildly abnormal study findings. (Study of Perfusion and Anatomys Role in Coronary Artery [CAD] [SPARC]; NCT00321399).

Repeatability and reproducibility of phase analysis of gated single-photon emission computed tomography myocardial perfusion imaging used to quantify cardiac dyssynchrony.

PURPOSE To evaluate postradiation regional heart perfusion changes with single photon emission tomography (SPECT) myocardial perfusion imaging in 69 patients treated with tangential photon beams radiation therapy (RT) for left-sided breast cancer. To correlate SPECT changes with percent irradiated left ventricle (LV) volume and risk factors for coronary artery disease (CAD). METHODS AND MATERIALS Rest SPECT of the LV was acquired pre-RT and at 6-month intervals post-RT. The extent of defects (%) with a severity > 1.5 standard deviations below the mean was quantitatively analyzed for the distributions of the left anterior descending (LAD) artery, left circumflex (LCX) artery, and right coronary artery (RCA) based on computer assisted polar map reconstruction (i.e., bulls-eye-view). Changes in perfusion were correlated with percent irradiated LV receiving > 25 Gy (range 0-32%). Data on patient- and treatment-related factors were collected prospectively (e.g., cardiac premorbidity, risk factors for CAD, chemotherapy, and hormonal treatment). RESULTS In the LAD distribution, there were increased perfusion defects at 6 months (median 11%; interquartile range 2-23) compared with baseline (median 5%; interquartile range 1-14) (p < 0.001). There were no increases in perfusion defects in the LCX or RCA distributions. In multivariate analysis, the SPECT perfusion changes in the LAD distribution at 6 months were independently associated with percent irradiated LV (p < 0.001), hormonal therapy (p = 0.005), and pre-RT hypercholesterolemia (p = 0.006). The SPECT defects in the LAD distribution at 12 and 18 months were not statistically different from those at 6 months. The perfusion defects in the LAD distribution were limited essentially to the regions of irradiated myocardium. CONCLUSION Tangential photon beam RT in patients with left-sided breast cancer was associated with short-term SPECT defects in the vascular distribution corresponding to the radiation portals. Factors related to the extent of perfusion defects included the percent irradiated LV, hormonal treatment, and pre-RT hypercholesterolemia.

Clinical significance of perfusion defects by thallium-201 single photon emission tomography following oral dipyridamole early after coronary angioplasty

PURPOSE To determine the incidence and dose dependence of regional cardiac perfusion abnormalities in patients with left-sided breast cancer treated with radiation therapy (RT) with and without doxorubicin (Dox). METHODS Twenty patients with left-sided breast cancer underwent cardiac perfusion imaging using single photon emission computed tomography (SPECT) prechemotherapy, pre-RT, and 6 months post-RT. SPECT perfusion images were registered onto 3-dimensional (3D) RT dose distributions. The volume of heart in the RT field was quantified, and the regional RT dose was calculated. A decrease in regional cardiac perfusion was assessed subjectively by visual inspection and objectively using image fusion software. Ten patients received Dox-based chemotherapy (total dose 120-300 mg/m(2)), and 10 patients had no chemotherapy. RT was delivered by tangent beams in all patients to a total dose of 46-50 Gy. RESULTS Overall, 60% of the patients had new visible perfusion defects 6 months post-RT. A dose-dependent perfusion defect was seen at 6 months with minimal defect appreciated at 0-10 Gy, and a 20% decrease in regional perfusion at 41-50 Gy. One of 20 patients had a decrease in left ventricle ejection fraction (LVEF) of greater than 10% at 6 months; 2/20 patients had developed transient pericarditis. No instances of myocardial infarction or congestive heart failure (CHF) have occurred. CONCLUSIONS RT causes cardiac perfusion defects 6 months post-RT in most patients. Long-term follow-up is needed to assess whether these perfusion changes are transient or permanent and to determine if these findings are associated with changes in overall cardiac function and clinical outcome.

Quantitative thallium-201 single photon emission computed tomography after oral dipyridamole for assessing the presence, anatomic location and severity of coronary artery disease

Radiation therapy (RT) to the left breast/chest wall has been linked with cardiac dysfunction. Previously, the authors identified cardiac perfusion defects in approximately 50% to 60% of patients 0.5 to 2 years post‐RT. In the current study, they assessed the persistence of these defects 3 to 6 years post‐RT.