Diagnostic value of PET-measured heterogeneity in myocardial blood flows during cold pressor testing for the identification of coronary vasomotor dysfunction.

BACKGROUND: We aimed to evaluate the diagnostic value of a positron emission tomography (PET)-measured heterogeneity in longitudinal myocardial blood flow (MBF) during cold pressor testing (CPT) and global MBF response to CPT from rest (DeltaMBF) for identification of coronary vasomotor dysfunction. METHODS AND RESULTS: In 35 patients CPT-induced alterations in epicardial luminal area were determined with quantitative angiography as the reference. MBF was assessed over the whole left ventricle as global MBF and regionally in the mid and mid-distal myocardium as MBF difference or MBF heterogeneity with nitrogen-13 ammonia and PET. The sensitivity and specificity of a longitudinal MBF difference during CPT in the identification of epicardial vasomotor dysfunction were significantly higher than the global DeltaMBF to CPT (88% vs 79% and 82% vs 64%, respectively; P < .05). Combining both parameters resulted in an optimal sensitivity of 100% at the expense of an intermediate specificity of 73%. The diagnostic accuracy was higher for the combined analysis than that for the MBF difference alone and global DeltaMBF alone (91% vs 86% and 74%, respectively; P < .05). CONCLUSIONS: The combined evaluation of a CPT-induced heterogeneity in longitudinal MBF and the change in global MBF from rest may emerge as a new promising analytic approach to further optimize the identification and characterization of coronary vasomotor dysfunction.

Positron emission tomography-measured abnormal responses of myocardial blood flow to sympathetic stimulation are associated with the risk of developing cardiovascular events.

OBJECTIVES: We sought to assess prospectively whether patients with normal coronary angiograms but with impaired myocardial blood flow (MBF) increases to cold pressor testing (CPT) are at increased risk for cardiovascular events. BACKGROUND: Invasive angiographic assessments of coronary vasomotor function have demonstrated an impairment of endothelium-related coronary flow increases to independently predict future cardiovascular events. It is unknown whether noninvasive positron emission tomography (PET)-measured MBF alterations to sympathetic stimulation with CPT are associated with the risk of developing cardiovascular events. METHODS: A total of 72 patients (44 men, 28 women, age 58 +/- 8 years) referred for diagnostic cardiac catheterization were studied. Myocardial blood flow was measured in absolute units with (13)N-ammonia using PET, at baseline and during CPT in each patient. Cardiovascular events (cardiovascular death, acute coronary syndrome, myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting, ischemic stroke, or peripheral revascularization) were assessed as clinical outcome parameters over a mean follow-up period of 66 +/- 8 months. Patients were assigned to three groups: group 1, patients with >/=40% increase in MBF (%DeltaMBF), n = 22; group 2, patients with >0 and <40% increases in MBF, n = 32; and group 3, patients with decreases in MBF (

Chronic inflammation and impaired coronary vasoreactivity in patients with coronary risk factors.

BACKGROUND: The goal of this study was to examine a possible association between systemic microinflammation, as reflected by C-reactive protein (CRP) serum levels, and coronary vasomotion in patients with coronary risk factors but with angiographically normal coronary arteries. METHODS AND RESULTS: Coronary vasomotor function was studied in response to cold pressor testing (CPT) in 71 patients with normal angiograms. In all patients, CPT-induced changes in epicardial luminal area (LA; mm2) were assessed with quantitative angiography. Within 20 days, myocardial blood flow (MBF) responses to CPT were measured (mL x g(-1) x min(-1)) noninvasively with 13N-ammonia and PET imaging. The CPT-induced mean changes in LA and in MBF in patients with elevated CRP (> or =0.5 mg/dL) were significantly impaired compared with patients presenting with CRP levels within normal range (<0.5 mg/dL) (DeltaLA, -1.09+/-0.86 versus 0.45+/-0.63 mm2; DeltaMBF, 0.06+/-0.18 versus 0.44+/-0.31 mL x g(-1) x min(-1); P<0.0001, respectively). Coronary LA changes and MBF responses to CPT were inversely correlated with CRP serum levels (r=-0.84 and r=-0.63; P<0.0001). Lastly, regression analysis revealed a significant correlation between the changes in LA and MBF during CPT for patients with elevated CRP levels and those for patients with normal CRP levels (r=0.56 and r=0.66; P<0.001). CONCLUSIONS: These findings suggest a direct association between systemic microinflammation and altered coronary vasomotor function of both the epicardial conductance and the arteriolar resistance vessels.

Myocardial viability in patients with ischemic cardiomyopathy-evaluation by 3-D integration of myocardial scintigraphic data--and coronary angiographic data.

PURPOSE: To determine the prevalence of viable myocardium in patients with ischemic cardiomyopathy and, to evaluate the value of three-dimensional (3-D) fusion imaging of myocardial scintigraphic and angiographic data to assign coronary artery lesions to the corresponding viable and nonviable myocardial territory. PROCEDURES: In 105 patients, the combination of perfusion and metabolic imaging with (201)thallium ((201)TI) single-photon emission computed tomography (SPECT) and 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) determined viability in dysfunctional myocardium. In addition, the value of 3-D scintigraphic fusion imaging was assessed in these patients. RESULTS: Based on the presence of viable dysfunctional myocardium, 54% of patients with ischemic cardiomyopathy may be considered for coronary revascularization. In 31 of 105 patients, the 3-D fusion imaging was estimated to be helpful in the diagnostic and interpretative process. CONCLUSION: In patients with end-stage coronary artery disease scintigraphic imaging is most important in the decision-making process. Three-dimensional fusion imaging may add important information in approximately 30% of these patients.

PET-measured responses of MBF to cold pressor testing correlate with indices of coronary vasomotion on quantitative coronary angiography.

UNLABELLED: The aims of this study were to determine whether responses in myocardial blood flow (MBF) to the cold pressor testing (CPT) method noninvasively with PET correlate with an established and validated index of flow-dependent coronary vasomotion on quantitative angiography. METHODS: Fifty-six patients (57 +/- 6 y; 16 with hypertension, 10 with hypercholesterolemia, 8 smokers, and 22 without coronary risk factors) with normal coronary angiograms were studied. Biplanar end-diastolic images of a selected proximal segment of the left anterior descending artery (LAD) (n = 27) or left circumflex artery (LCx) (n = 29) were evaluated with quantitative coronary angiography in order to determine the CPT-induced changes of epicardial luminal area (LA, mm(2)). Within 20 d of coronary angiography, MBF in the LAD, LCx, and right coronary artery territory was measured with (13)N-ammonia and PET at baseline and during CPT. RESULTS: CPT induced on both study days comparable percent changes in the rate x pressure product (%DeltaRPP, 37% +/- 13% and 40% +/- 17%; P = not significant [NS]). For the entire study group, the epicardial LA decreased from 5.07 +/- 1.02 to 4.88 +/- 1.04 mm(2) (DeltaLA, -0.20 +/- 0.89 mm(2)) or by -2.19% +/- 17%, while MBF in the corresponding epicardial vessel segment increased from 0.76 +/- 0.16 to 1.03 +/- 0.33 mL x min(-1) x g(-1) (DeltaMBF, 0.27 +/- 0.25 mL x min(-1) x g(-1)) or 36% +/- 31% (P