Mitsutoshi Yamada

Value of dipyridamole thallium-201 imaging in noninvasive differentiation of idiopathic dilated cardiomyopathy from coronary artery disease with left ventricular dysfunction

The purpose of this study was to noninvasively differentiate in patients with reduced global left ventricular function between those with idiopathic dilated cardiomyopathy (IDC) and coronary artery disease (CAD). Clinical features and findings of dipyridamole thallium-201 imaging in 55 consecutive patients with IDC were compared with those in 77 with CAD. Left ventricular ejection fraction was similar between the 2 groups (34 +/- 16% vs 39 +/- 7%). Patients with IDC had lower incidences of ischemic chest pain (11 vs 79%; p less than 0.0001), electrocardiographic evidence of myocardial infarction (24 vs 82%; p less than 0.0001), and reversible defects (4 vs 57%; p less than 0.0001) than did those with CAD. The lowest percent thallium uptake in the initial imaging was less with CAD than IDC (30 +/- 15% vs 59 +/- 10%; p less than 0.001). Patterns of perfusion defects were classified as: no defects, multiple small defects and large defects. Of patients with IDC, 15 had no defects, 19 had multiple small defects, and 21 had large defects, whereas all those with CAD had large defects (p less than 0.0001). Stepwise discriminant analysis, using chest pain and electrocardiography, revealed sensitivity of 89%, specificity of 87%, accuracy of 88%, and positive predictive value of 83% in the identification of patients with IDC.(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive identification of significant narrowing of the left main coronary artery by dipyridamole thallium scintigraphy

To evaluate the usefulness of dipyridamole thallium scintigraphy with low-level exercise for the identification of left main (LM) coronary artery disease (CAD), 466 consecutive patients with CAD were studied. Thirty-eight patients (8%) had LM stenosis (diameter narrowing greater than or equal to 50%). The LM scintigraphic pattern was present in 9 of 38 patients with LMCAD and 38 of 428 CAD patients without LMCAD (24 vs 9%; p less than 0.005). This pattern was present in 6 of 9 patients with LMCAD without right CAD and in only 3 of 29 patients with LM and right CAD (67 vs 10%; p = 0.0005). Patients with LMCAD had a higher incidence of premature cessation of low-level exercise (53 vs 21%; p less than 0.0001), chest pain (68 vs 48%; p less than 0.02), blood pressure decrease of greater than or equal to 20 mm Hg (44 vs 16%; p less than 0.002) and greater ST depression (0.17 +/- 0.13 vs 0.06 +/- 0.10 mV; p less than 0.001) during dipyridamole loading than patients without LMCAD. Stepwise discriminant analysis revealed that the LM scintigraphic pattern and markers of ischemia during dipyridamole loading best identified (p less than 0.0001) patients with LMCAD without right CAD (sensitivity 67%, specificity 91%), but this predictability is no better than the LM scintigraphic pattern alone. The combination of clinical markers of ischemia during dipyridamole loading and scintigraphic findings of diffuse slow washout, extensive fixed defects and the LM pattern best identified (p less than 0.0001) patients with LM and right CAD (sensitivity 72%, specificity 80%).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognosis of asymptomatic elderly patients with aortic stenosis

To elucidate the prognosis of elderly patients with asymptomatic aortic stenosis (AS) and to assess the timing of aortic valve replacement (AVR), 21 asymptomatic patients (8 men, 13 women, mean age: 75 +/- 8 years (54-89 years)), who had Doppler echocardiographic evidence of a significant aortic pressure gradient of greater than 40 mmHg (mean gradient: 75 +/- 31 mmHg), were followed for 33 +/- 10 months. During the follow-up, there were 4 cardiac events (2 cardiac deaths, 2 late AVRs), and 2 non-cardiac deaths (cerebro-vascular accidents). Among 15 survivors, 13 patients were in NYHA class I--II, and the remaining 2 patients were found to have malignant disease. Compared to the 17 patients without cardiac events, those with cardiac events had significantly larger CTR (58 +/- 6% vs. 53 +/- 3%; p less than 0.01), although there were no significant difference in electrocardiographic LVH, echocardiographic LV mass, and Doppler pressure gradient between the two groups. The prevalence of the development of cardiac symptoms during the follow-up was not high (12%) in patients without cardiac events. Among 4 patients with cardiac events, one patient who was 89 years-old at diagnosis died of heart failure, one patient had fatal myocardial infarction which seemed to be unrelated to AS, and two patients had successful late AVR because of new heart failure. The low incidence of fatal cardiac events in asymptomatic patients with aortic stenosis and the relatively high possibility of developing non-cardiac events in elderly patients indicate that the decision-making for AVR should not be solely based upon the pressure gradient detected by Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)