Marcassa C, Galli M, Temporelli P L, Campini R, Orrego P S, Zoccarato O, Giordano A, Giannuzzi P
Cardiology Division, Clinica del Lavoro Foundation, Istituto Ricovero e Cura a Carattere Scientifico (IRCCS), Veruno, Italy.
J Am Coll Cardiol. 1995 Mar 1;25(3):590-6. doi: 10.1016/0735-1097(94)00451-U.
This study investigated the value of sestamibi scintigraphy in assessing residual ischemia after anterior myocardial infarction.
Serial imaging with sestamibi, the uptake and retention of which correlate with regional myocardial blood flow and viability, has been used to estimate salvaged myocardium and risk area after acute infarction. We recently documented that recovery of perfusion and contraction in the infarcted area may continue well after the subacute phase, suggesting myocardial hibernation. Some underestimation of viability in the setting of hibernating myocardium by sestamibi imaging has been reported.
We studied 58 patients in stable condition after Q wave anterior infarction. Regional perfusion and function were quantitatively assessed by sestamibi tomography and two-dimensional echocardiography at 4 to 6 weeks and at 7 months after infarction. In sestamibi polar maps, abnormal areas with tracer uptake > 2.5 SD below our reference values were computed at rest and after symptom-limited exercise. On two-dimensional echocardiography the ejection fraction and extent of rest wall motion abnormalities were assessed by a computerized system. All patients had coronary angiography between the two studies.
At 7 months the extent of rest sestamibi defect was significantly reduced in 40 patients (69%, group 1) and unchanged in 18 (31%, group 2). Rest wall motion abnormalities and ventricular ejection fraction significantly improved in group 1 but not in group 2. Underlying coronary disease, patency of the infarct-related vessel and rest sestamibi defect extent at 5 weeks were comparable between the two groups. At 7 months, an increase in the reversible (stress-rest defect) tracer defect was observed in group 1 (p < 0.05) despite a smaller stress-induced hypoperfusion (p < 0.05). Reversible sestamibi defects and stress hypoperfusion were unchanged in group 2. In 38 (95%) of 40 group 1 patients, the area showing reversible sestamibi defects at 7 months matched the area showing fixed hypoperfusion at 5 weeks.
The reduction in the rest tracer uptake defect that can occur late after infarction may affect the assessment of ischemic burden by sestamibi imaging early after anterior myocardial infarction.
本研究探讨了心肌灌注显像（sestamibi scintigraphy）在前壁心肌梗死后评估残余心肌缺血方面的价值。
心肌灌注显像的系列成像，其摄取和滞留与局部心肌血流及存活心肌相关，已被用于评估急性心肌梗死后挽救的心肌和危险区域。我们最近记录到梗死区域灌注和收缩功能在亚急性期后仍可继续良好恢复，提示心肌冬眠。已有报道指出，在心肌冬眠情况下，心肌灌注显像对存活心肌的评估存在一定程度的低估。
我们研究了58例Q波前壁心肌梗死后病情稳定的患者。在梗死后4至6周以及7个月时，通过心肌灌注显像断层扫描和二维超声心动图对局部灌注和功能进行定量评估。在心肌灌注显像极坐标图中，计算静息状态及症状限制性运动后示踪剂摄取低于我们参考值2.5个标准差的异常区域。通过计算机系统在二维超声心动图上评估射血分数和静息时室壁运动异常的范围。所有患者在两次研究之间均接受了冠状动脉造影。
7个月时，40例患者（69%，第1组）静息心肌灌注显像缺损范围显著缩小，18例患者（31%，第2组）无变化。第1组静息时室壁运动异常和心室射血分数显著改善，而第2组未改善。两组患者的基础冠状动脉疾病、梗死相关血管通畅情况以及5周时静息心肌灌注显像缺损范围相当。7个月时，第1组患者尽管应激诱导的灌注不足较小（p<0.05），但可逆性（应激-静息缺损）示踪剂缺损增加（p<0.05）。第2组可逆性心肌灌注显像缺损和应激性灌注不足无变化。在第1组40例患者中的38例（95%）中，7个月时显示可逆性心肌灌注显像缺损的区域与5周时显示固定性灌注不足的区域相符。
梗死后晚期可能出现的静息示踪剂摄取缺损减少，可能会影响前壁心肌梗死后早期通过心肌灌注显像对缺血负荷的评估。
