Safety, feasibility, and diagnostic accuracy of accelerated high-dose dipyridamole stress echocardiography.

Protocols for dipyridamole stress testing have evolved in the last 16 years in the neverending quest of optimal diagnostic accuracy and user friendliness. Higher dipyridamole dose in a shorter infusion time provides higher sensitivity, but concern over safety is still controversial. An accelerated high-dose (0.84 mg/kg in 6 minutes without atropine) dipyridamole stress test was performed on 1,295 patients in 2 echocardiographic laborotories: Institute of Clinical Physiology of Pisa and Niguarda Hospital of Milan. During testing, there were no deaths and no patients had ventricular fibrillation. Major adverse reactions occurred in 3 cases (1 every 431 studies): 1 myocardial infarction, 1 brief cardiac asystole, and 1 transient ischemic attack. Overall feasibility was 97%. In 66 patients with normal function at rest who were evaluated off therapy, with coronary angiography performed independently of test results, the accelerated high-dose protocol showed a sensitivity of 85% (confidence interval [CI] 73% to 92%) and a specificity of 93% (CI 83% to 97%) for angiographically assessed coronary artery disease (quantitatively assessed diameter reduction > or = 50%). Diagnostic accuracy of the accelerated high dose was 89% (CI 79% to 95%). Thus, accelerated high-dose dipyridamole stress echocardiography was reasonably safe and well tolerated. This protocol is especially appealing for its excellent diagnostic accuracy coupled with the short imaging time and no need for drug cocktails.

The impact of second harmonic imaging on stress echocardiography reading.

BACKGROUND: Noncontrast harmonic significantly improves overall image quality in echocardiography. The aim of this study was to assess whether harmonic imaging, without contrast, impacts on interobserver variability and diagnostic accuracy of "beginners" in stress echocardiography. METHODS: Images at rest and peak stress were obtained in digitized format in 15 consecutive patients (10 males, 5 females, mean age 66 +/- 9 years) and analyzed by 5 inexperienced observers (stress echo beginners) who were blinded to the imaging modality (standard versus harmonic imaging). Each observer graded the image quality as 1 = uninterpretable up to 5 = excellent, in a total of 240 segments. RESULTS: The mean image quality per segment was 2.9 for conventional technology and increased up to 3.6 for harmonic imaging (p < 0.001). The interobserver agreement (> or = 4 out of 5 readers) rose from 46 to 60%. The percentage of uninterpretable segments was 7.5% at rest and 8.9% at peak stress of conventional imaging, and decreased to 4.6 and 6.5%, respectively (p < 0.05) by second harmonic technology. The unanimous reading of two additional independent expert observers was arbitrarily assumed to be the "gold standard" to verify the accuracy of reading of the 5 beginners. The 5 beginners showed poor diagnostic accuracy with fundamental imaging (73%), and they did not improve with second harmonic imaging (70%, NS vs fundamental). CONCLUSIONS: Noncontrast second harmonic imaging improves image quality over conventional imaging. The improved quality of the image deflated interobserver variability but did not determine per se an improvement in the diagnostic accuracy of nonexperienced readers.