Effect on treadmill exercise capacity, myocardial ischemia, and left ventricular function as a result of repeated whole-body periodic acceleration with heparin pretreatment in patients with angina pectoris and mild left ventricular dysfunction.

Whole-body periodic acceleration (WBPA) has been developed as a passive exercise device capable of improving endothelial function by applying pulsatile shear stress to vascular endothelium. We hypothesized that treatment with WBPA improves exercise capacity, myocardial ischemia, and left ventricular (LV) function because of increased coronary and peripheral vasodilatory reserves in patients with angina. Twenty-six patients with angina who were not indicated for percutaneous coronary intervention and/or coronary artery bypass grafting were randomly assigned to remain sedentary (sedentary group) or undergo 20 sessions of WBPA with the motion platform for 4 weeks (WBPA group) in addition to conventional medical treatment. WBPA was applied at 2 to 3 Hz and approximately ±2.2 m/s² for 45 minutes. We repeated the symptom-limited treadmill exercise test and adenosine sestamibi myocardial scintigraphy. In the WBPA group, the exercise time until 0.1-mV ST-segment depression increased by 53% (p <0.01) and the double product at 0.1-mV ST-segment depression by 23% (p <0.001). Severity score of myocardial scintigraphy during adenosine infusion decreased from 20 ± 10 to 14 ± 8 (p <0.001) and severity score at rest also decreased from 13 ± 10 to 8 ± 10 (p <0.01). On scintigraphic images at rest, LV end-diastolic volume index decreased by 18% (p <0.01) with an augmentation of LV ejection fraction from 50 ± 16% to 55 ± 16% (p <0.01). In contrast, all studied parameters remained unchanged in the sedentary group. In conclusion, treatment with WBPA for patients with angina ameliorates exercise capacity, myocardial ischemia, and LV function.

Complementary appearance of glucose and lipid metabolism in cardiac sarcoidosis.

Sarcoidosis is a non-caseating granulomatous systemic disease of unknown pathogenesis, and cardiac involvement is the most important prognostic factor. We have evaluated the value of the combined study of F-18 fluoro-2-deoxyglucose positron emission tomography and iodine-123 labeled 15-(p-iodophenyl)-3R,S-methylpentadecanoic acid single-photon emission tomography for the assessment of cardiac involvement of sarcoidosis, by comparing the findings with gadolinium magnetic resonance in a patient with histologically-proven cardiac sarcoidosis.

A catheter-based intravascular radiation detector of vulnerable plaques.

UNLABELLED: Detection of vulnerable plaques before rupture is important in preventing acute coronary events such as myocardial infarction. Although therapeutic strategies such as percutaneous transluminal coronary angioplasty appear to prevent coronary occlusion and consequently may lead to improved prognosis in these patients, a method of detecting vulnerable plaques has not been established. A nuclear method that uses an intravascular radiation detector (IVRD) with the plaque-avid tracer (18)F-FDG is one of the most promising methods. The catheter-based IVRD consists of a catheter probe (a scintillator and flexible optic fibers), photomultipliers, a controller, and an automatic pullback unit and personal computer. A phantom study demonstrated that this detector was highly sensitive to (18)F and enabled the detection of (18)F point sources. However, details of the detection system in vivo remain unclear. METHODS: To evaluate vulnerable plaques in vivo, we investigated a canine femoral artery and coronary artery using this detector system. Our goal was to estimate the ability of this device to navigate through these arteries and to detect (18)F point sources fixed on their adventitia. RESULTS: In the study using a canine femoral artery, the IVRD could detect the point sources with good repeatability. In the study using an open-chest canine model, the catheter probe could easily be advanced into the left descending coronary artery, and the IVRD could detect target sources attached externally to the coronary artery (7- to 15-mm intervals) with good resolution. CONCLUSION: This newly developed catheter-based IVRD was able to detect, with good resolution, the slight radioactivity from (18)F point sources attached to the femoral artery and the coronary adventitia. These results show that catheter-based detection of coronary vulnerable plaques may be feasible.

Comparison of myocardial blood flow induced by adenosine triphosphate and dipyridamole in patients with coronary artery disease.

Myocardial perfusion imaging with adenosine triphosphate (ATP) has been used increasingly to diagnose coronary artery disease (CAD) and assess risk for this disease. This study compared absolute myocardial blood flow (MBF) and myocardial flow reserve index (MFR) with ATP and dipyridamole (DIP) in patients with CAD. MBF was quantified by 15O-H2O PET in 21 patients with CAD (17 male, 4 female), aged 55 to 81 years. MBF was measured at rest, during intravenous injection of ATP (0.16 mg/kg/min), and again after DIP infusion (0.56 mg/kg). Regions of interest were drawn in nonischemic and ischemic segments based on findings from thallium-201 (201T1) scintigraphy and coronary angiography (CAG). Absolute MBF values and indexes of MFR were calculated in nonischemic and ischemic segments. Intravenous injection of ATP and DIP significantly increased MBF in nonischemic (2.4 +/- 0.9 and 2.1 +/- 0.8 ml/g/min, respectively; p < 0.01, for both) and in ischemic segments (1.3 +/- 0.4 and 1.5 +/- 0.4 ml/g/min, respectively; p < 0.01, for both). There was a significant difference in MBF values between ATP and DIP in nonischemic segments (p < 0.05), which was not observed in ischemic segments. In nonischemic segments, ATP produced higher MFR than DIP (2.1 +/- 0.8 and 1.8 +/- 0.7, respectively; p < 0.05), while no significant difference was observed in ischemic segments (1.5 +/- 0.6 and 1.7 +/- 0.3, respectively). ATP produced a greater hyperemia than DIP between the ischemic and nonischemic myocardium in patients with CAD. ATP is as effective as DIP for the diagnosis of CAD.