Storto G, Gallicchio R, Maddalena F, Pellegrino T, Petretta M, Fiumara G, Cuocolo A
IRCCS, CROB, Rionero in Vulture, Potenza, Italy -
Q J Nucl Med Mol Imaging. 2015 Sep;59(3):336-41. Epub 2014 Mar 21.
Patients with hypertension may exhibit abnormal vasodilator capacity during pharmacological vasodilatation. We assessed coronary flow reserve (CFR) by sestamibi imaging in hypertensive patients with normal coronary vessels.
Twenty-five patients with untreated mild essential hypertension and normal coronary vessels and 10 control subjects underwent dipyridamole-rest Tc-99m sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in pulmonary artery and myocardial counts from tomograhic images. CFR was expressed as the ratio of stress to rest MBF. Coronary vascular resistances (CVR) were computed as the ratio between mean arterial pressure and MBF.
Estimated MBF at rest was not different in patients and controls (1.11 ± 0.59 vs. 1.14 ± 0.28 counts/pixel/s; P=0.87). Conversely, stress MBF was lower in patients than in controls (1.55 ± 0.47 vs. 2.68 ± 0.53 counts/pixel/s; P<0.001). Thus, CFR was reduced in patients compared to controls (1.61 ± 0.58 vs. 2.43 ± 0.62; P<0.001). Rest and stress CVR values were higher in patients (P<0.001), while stress-induced changes in CVR were not different (P=0.08) between patients (-51%) and controls (-62%). In the overall study population, a significant relation between CFR and stress-induced changes in CVR was observed (r=-0.86; P<0.001).
Sestamibi imaging may detect impaired coronary vascular function in response to dipyridamole in patients with untreated mild essential hypertension and normal coronary arteries. A mild increase in arterial blood pressure does not affect baseline MBF, but impairs coronary reserve due to the amplified resting coronary resistances.
高血压患者在药物性血管舒张过程中可能表现出异常的血管舒张能力。我们通过心肌灌注显像评估了冠状动脉正常的高血压患者的冠状动脉血流储备（CFR）。
25例未经治疗的轻度原发性高血压且冠状动脉正常的患者和10名对照者接受了双嘧达莫负荷-静息锝-99m甲氧基异丁基异腈心肌灌注显像。通过测量肺动脉首次通过计数和断层图像上的心肌计数来估算心肌血流量（MBF）。CFR表示为负荷与静息MBF的比值。冠状动脉血管阻力（CVR）计算为平均动脉压与MBF的比值。
患者和对照者静息时估算的MBF无差异（1.11±0.59对1.14±0.28计数/像素/秒；P=0.87）。相反，患者负荷时的MBF低于对照者（1.55±0.47对2.68±0.53计数/像素/秒；P<0.001）。因此，与对照者相比，患者的CFR降低（1.61±0.58对2.43±0.62；P<0.001）。患者静息和负荷时的CVR值较高（P<0.001），而患者（-51%）和对照者（-62%）之间负荷诱导的CVR变化无差异（P=0.08）。在整个研究人群中，观察到CFR与负荷诱导的CVR变化之间存在显著相关性（r=-0.86；P<0.001）。
心肌灌注显像可能检测到未经治疗的轻度原发性高血压且冠状动脉正常的患者在双嘧达莫作用下冠状动脉血管功能受损。动脉血压轻度升高不影响基线MBF，但由于静息冠状动脉阻力增加而损害冠状动脉储备。
