Objective: To study the prevalence and clinical characteristics of decreased myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) in symptomatic patients without in-stent restenosis.
Materials and Methods: Thirty-seven (mean age, 71.3 +/- 10 years; age range, 48-88 years; 31 males, 6 females) consecutive symptomatic patients with patent coronary stents and without obstructive de novo lesions were prospectively enrolled to undergo dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used to image the complete left ventricle. A bolus of contrast media (50 mL; iopromide, 370 mg iodine/mL) was injected into the antecubital vein at a rate of 6 mL/s, followed by a 40-mL saline flush. The mean MBF value and other quantitative parameters were measured for each segment of both stented-vessel territories and reference territories. The MBFratio was defined as the ratio of the mean MBF value of the whole stent-vessel territory to that of the whole reference territory. An MBFratio of 0.85 was used as the cut-off value to distinguish hypoperfused from non-hypoperfused segments.
Results: A total of 629 segments of 37 patients were ultimately included for analysis. The mean effective dose of dynamic CT-MPI was 3.1 +/- 1.2 mSv (range, 1.7-6.3 mSv). The mean MBF of stent-vessel territories was decreased in 19 lesions and 81 segments. Compared to stent-vessel territories without hypoperfusion, the mean MBF and myocardial blood volume were markedly lower in hypoperfused stent-vessel territories (77.5 +/- 16.6 mL/100 mL/min vs. 140.4 +/- 24.1 mL/100 mL/min [p < 0.001] and 6.4 +/- 3.7 mL/100 mL vs. 11.5 +/- 4 mL/100 mL [p < 0.001, respectively]). Myocardial hypoperfusion in stentvessel territories was present in 48.6% (18/37) of patients. None of clinical parameters differed statistically significantly between hypoperfusion and non-hypoperfusion subgroups.
Conclusion: Decreased MBF is commonly present in patients who are symptomatic after percutaneous coronary intervention, despite patent stents and can be detected by dynamic CT-MPI using a low radiation dose.
[1]Shanghai Jiao Tong Univ, Affiliated Peoples Hosp 6, Inst Diagnost & Intervent Radiol, 600 Yishan Rd, Shanghai, Peoples R China.
[2]Shanghai Univ Med & Hlth Sci, Affiliated Zhoupu Hosp, Dept Radiol, Shanghai, Peoples R China.
[3]Shanghai Jiao Tong Univ, Affiliated Peoples Hosp 6, Dept Cardiol, Shanghai, Peoples R China.
[4]Chinese Acad Med Sci, Peking Union Med Coll Hosp, Dept Radiol, Beijing, Peoples R China.
[5]Peking Union Med Coll, Beijing, Peoples R China.
[6]Chinese Acad Med Sci, Fuwai Hosp, Natl Ctr Cardiovasc Dis, State Key Lab Cardiovasc Dis,Dept Radiol, Beijing, Peoples R China.
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