The diagnostic role of resting myocardial blood flow in STEMI patients after revascularization.

Background: The value of semiquantitative resting myocardial perfusion imaging (MPI) in coronary artery disease (CAD) is limited. At present, quantitative MPI can be performed by a new cadmium zinc tellurium single-photon emission computed tomography (CZT-SPECT) scan. The quantitative index of resting myocardial blood flow (MBF) has received little attention, and its manifestations and clinical value in the presence of unstable coronary blood flow have not been clarified. Purpose: In patients with ST-segment elevation myocardial infarction (STEMI), whether resting MBF can provide additional value of blood flow than semi-quantitative resting MPI is not sure. We also explored the influencing factors of resting MBF. Methods: This was a retrospective clinical study. We included 75 patients with STEMI in the subacute phase who underwent resting MPI and dynamic scans after reperfusion therapy. General patient information, STEMI-related data, MPI, gated MPI (G-MPI), and resting MBF data were collected and recorded. According to the clinically provided culprit vessels, the resting MBF was divided into ischemic MBF and non-ischemic MBF. The paired Wilcoxon signed-rank test was used for resting MBF. The receiver operating characteristic (ROC) curves were used to determine the optimal threshold for ischemia, and multiple linear regression analysis was used to analyze the influencing factors of resting MBF. Results: There was a statistically significant difference between the ischemic MBF and non-ischemic MBF [0.59 (0.47-0.72) vs. 0.76 (0.64-0.93), p < 0.0001]. The ROC curve analysis revealed that resting MBF could identify ischemia to a certain extent, with a cutoff value of 0.5975, area under the curve (AUC) = 0.666, sensitivity = 55.8%, and specificity = 68.7%. Male sex and summed rest score (SRS) were influencing factors for resting MBF. Conclusion: To a certain extent, resting MBF can suggest residual ischemia after reperfusion therapy in patients with STEMI. There was a negative correlation between male sex, SRS, and ischemic MBF. A lower resting MBF may be associated with more severe myocardial ischemia.

A preliminary study of dobutamine myocardial flow reserve on 99mTc-Sestamibi CZT-SPECT.

BACKGROUND: With improved resolution and sensitivity, the cadmium zinc telluride (CZT) detector measures myocardial blood flow (MBF) and myocardial flow reserve (MFR) via single photon emission computed tomography (SPECT). Recently, many studies have used vasodilator stress to obtain quantitative indexes. However, dobutamine used as a pharmaceutical stress has been rarely used to quantify myocardial perfusion using CZT-SPECT. Our study retrospectively analyzed the blood flow performance of 99mTc-Sestamibi (99mTc -MIBI) CZT-SPECT comparing dobutamine to adenosine. PURPOSE: The study aims to explore whether dobutamine stress can be used for the myocardial perfusion quantitative analysis via CZT-SPECT as well as compare dobutamine MBF and MFR to adenosine. METHODS: It was a retrospective study. A total of 68 patients with suspected or known coronary artery disease (CAD) were consecutively enrolled in this study. Thirty-four patients underwent dobutamine stress 99mTc-MIBI CZT-SPECT. Another thirty-four patients underwent adenosine stress 99mTc-MIBI CZT-SPECT. Patient characteristics, myocardial perfusion imaging (MPI) results, gated-myocardial perfusion imaging (G-MPI) results and quantitative analysis of MBF and MFR were collected. RESULTS: In dobutamine stress group, stress MBF was significantly higher than rest MBF (median [interquartile range], 1.63 [1.46-1.94] vs. 0.89 [0.73-1.06], P < 0.001). In adenosine stress group, similar results were observed (median [interquartile range], 2.01 [1.34-2.20] vs. 0.88 [0.75-1.01], P < 0.001). When comparing the dobutamine and adenosine stress group, global MFR showed significant differences (median [interquartile range], the dobutamine group: 1.88 [1.67-2.38] vs. the adenosine group: 2.19 [1.87-2.64], P = 0.037). CONCLUSION: MBF and MFR can be measured using dobutamine 99mTc -MIBI CZT-SPECT. In small sample single-center study, there was a difference in MFR produced by adenosine and dobutamine within the suspected or the known CAD population.

Characteristics of the beta-globin gene cluster haplotypes of three Han Chinese populations at Beijing, Xi'an, and Kunming as compared with those of other Asian populations.

Haplotype frequencies of the beta-globin gene cluster of Han Chinese at Beijing, Xi'an, and Kunming were estimated, and their mutual genetic relationships were examined and compared to those of Buryats, Khalkhs, Evenkis, Oroqens, Koreans, and Colombian Amerindians. A major 5' subhaplotype (5' to the delta-globin gene), a major 3' subhaplotype (in and 3' to the beta-globin gene), and a major haplotype (combination of 5' and 3' subhaplotypes) are represented as + - - - -, - +, and + - - - - - +, respectively, and found in all three Han Chinese. A rare 5' subhaplotype, - - - - -, which is one of the possible ancestral types, was found only in Han Chinese at Kunming at low frequency (0.013), and a rare 3' subhaplotype, - -, was also observed in all three Han Chinese at low frequencies (0.009-0.014). The present haplotype frequency study suggested that the highest genetic affinity was found between Han Chinese at Beijing and those at Xi'an; the next highest was between Han Chinese at Beijing and Koreans, followed by that between Han Chinese at Beijing and Khalkhs, then that between Han Chinese at Xi'an and those at Kunming or Khalkhs, and finally that between Han Chinese at Beijing and those at Kunming. A genetic boundary between northern and southern Han Chinese was not evident in the present study.

Beta-globin gene cluster haplotype frequencies in Khalkhs and Buryats of Mongolia.

Beta-globin gene cluster haplotype frequencies of 169 Khalkhs and 145 Buryats were estimated, and their characteristics were compared with those of Evenkis, Oroqens, Koreans, Japanese, and three Colombian Amerindian groups. The present study suggests that Colombian Amerindians diverged first from Asian populations and then Buryats diverged from other Asian populations.

Characteristic beta-globin gene cluster haplotypes of Evenkis and Oroqens in north China.

Haplotype frequencies of the beta-globin gene cluster were estimated for 114 Evenkis and 81 Oroqens from northeast China, and their characteristics were compared with those in Japanese, Koreans, and three Colombian Amerindian groups of South America (Wayuu, Kamsa, and Inga tribes). A major 5' subhaplotype (5' to the delta-globin gene) was + - - - - in Evenkis, whereas + - - - -, - + + - +, and - + - + + were the major subhaplotypes in Oroqens. One possible candidate for an ancestral 5' subhaplotype, - - - - -, was found in one Evenki (0.5%) and three Oroqen chromosomes (2.0%). They were observed as heterozygous forms for + ---- and -----. Major haplotypes were +-----+, + -----+-, and + - - - - + + in Evenkis, whereas they were +-----+,-++-+-+, +----+-, and -+-++-+ in Oroqens. The lowest Nei's genetic distance values of Evenkis or Oroqens based on the 5' subhaplotype frequency distributions were observed in relation to the Wayuu or Koreans, respectively, but those of Evenkis and Oroqens based on the haplotype frequency distributions were found in relation to Koreans.