Adenosine stress protocols for nuclear cardiology imaging.

UNLABELLED: The treadmill test combined with myocardial perfusion imaging (MPI) is a commonly used technique in the assessment of coronary artery disease (CAD). However, there is a group of patients who may not be able to undergo the treadmill test. Pharmacologic stress testing is increasingly utilized for stress perfusion imaging and currently accounts for nearly 40% of all nuclear stress testing [8]. The aim of this study was the introduction of adenosine stress protocols in our nuclear laboratory, and the following, recording and comparing of the frequency and severity of side-effects. METHODS: We performed two kinds of adenosine stress protocols on 186 patients who underwent MPI with radiotracer 99mTc-sestamibi: 1st: 47 patients underwent AdenoSCAN abbreviated protocol IV. adenosin 140microg/kg/min for 3 minutes; 2nd: AdenoEX combined with low level 50W bicycle exercise in 139 patients. We followed and compared side-effects (minor and major events) between AdenoSCAN and AdenoEX protocol, and established an adequate time for imaging of both protocols. RESULTS: Compared with AdenoSCAN, AdenoEX protocol was tolerated by all patients; it reduced all side-effects and improved image quality. Using AdenoEX protocol we found that the heart-to-liver ratio was significantly better, and we established a time of imaging of 15 minutes after stress, compared to the AdenoSCAN time of imaging which was a minimum of 45 minutes after stress. CONCLUSION: This study gives advatages to AdenoEX protocol, because it had fewer side-effects, improved patients' tolerance, improved image quality, and enhanced efficiency and throughput given the opportunity for earlier imaging.

Determination of culprit lesion in patients undergoing elective percutaneous coronary intervention by myocardial perfusion imaging.

UNLABELLED: The aim of this study was to determine and localize culprit lesion by myocardial perfusion imaging (MPI) in cases of angiographically detected coronary narrowing >or= 75% of at least one coronary artery. MATERIAL AND METHODS: One hundred and thirty-two (132) patients with angiographically detected significant coronary narrowing (>or= 75% luminal stenosis of at least one major coronary artery) were studied. All the patients submitted MPI (99m)Tc-MIBI, with pharmacologic dipyridamole stress protocol with concomitant low level bicycle exercise 50W (DipyEX). We measured relative uptake (99m)Tc-MIBI for each myocardial segment using short-axis myocardial tomogram study. A 5-point scoring system was used to assess the difference between uptake degree in stress and rest studies for the same segments, and we created two indices: Sum reversibility score (SRS), Index of sum reversibility score (ISRS). RESULTS: A total of 396 vascular territories (2244 segments) were analyzed before elective percutaneous coronary intervention (ePCI). Overall sensitivity, specificity and accuracy using SRS were 90.2%, 87.5%, and 89.4%, with a positive predictive value of 94.1%. Overall sensitivity, specificity, and accuracy using ISRS were 94.4%, 90.6%, 93.2% and the positive predictive value was 95.7%. CONCLUSION: DipyEX MPI with the two indices created, SRS and ISRS, significantly improves sensitivity, specificity and accuracy in the determination and localization of culprit lesions in patients undergoing elective PCI.

Direct intracoronary stent implantation.

The standard stent implantation technique requires routine predilatation of the target lesion with balloon catheter. Since occurrence of complications is possible, direct stent implantation without previous dilatation has been performed recently. In this study, a complex case of coronary lesion treated with direct stent implantation in a patient with unstable angina after diaphragmal myocardial infarction was reported. A coronary angiography finding indicated presence of severe eccentric stenosis in the proximal third of the dominant right coronary artery. The system of the left coronary artery was without stenotic lesions. After antiaggregation combination of aspirin and ticlopidine, the stent was successfully implanted and dilated under the pressure of 14 atmospheres. The control coronary angiography did not show residual stenosis of the right coronary artery. The patient was discharged without subjective discomforts for further out-patient treatment.