Usmani Sharjeel, Khan Haider Ali, Zaman Maseeh-Uz, Niyaz Kashif
Department of Nuclear Medicine, Karachi Institute of Radiotherapy and Nuclear Medicine, Karachi, Pakistan.
Med Princ Pract. 2009;18(4):310-6. doi: 10.1159/000215730. Epub 2009 Jun 2.
To determine the prognostic value of myocardial perfusion scintigraphy with dipyridamole stress in patients with preexisting left bundle-branch block (LBBB) with or without chest pain.
Seventy-six patients, mean age 53 +/- 10 years, with preexisting LBBB underwent technetium-99m-sestamibi perfusion imaging with dipyridamole infusion protocol (0.56 mg/kg). Stress and rest single photon emission computed tomography (SPECT) images were interpreted by consensus of 2 experienced nuclear medicine physicians and classified as low-risk scans (normal myocardial perfusion scan, small reversible/small fixed defect) and high-risk scans (large, severe, fixed or reversible defect and dilated left ventricle cavity). The patients were followed up for 24 +/- 8 months and occurrences of hard cardiac events (infarction or cardiac death) were noted.
Of the 76 patients, 52 (68%) had low-risk scans and the remaining 24 (32%) had high-risk scans. In the low-risk group, 1 (1.9%) cardiac death and 2 (3.8%) cases of nonfatal myocardial infarction occurred, while in the high-risk group, 5 (20.8%) suffered cardiac death, and 3 (12.5%) nonfatal myocardial infarction. Overall survival rate was 98.1% in the low-risk group compared with 79.2% in the high-risk group with a significant difference of p = 0.034. Negative predictive value of normal myocardial perfusion scintigraphy for the occurrence of death was 100%. No significant difference in survival rate among patients with or without chest pain (p = 0.31) was observed.
Myocardial perfusion imaging with dipyridamole provided important prognostic information in patients with LBBB; it was useful in stratifying the patients according to cardiovascular morbidity and mortality, and would thus allow the clinician to provide early treatment especially in the high-risk category.
确定双嘧达莫负荷心肌灌注显像对已有左束支传导阻滞（LBBB）且有或无胸痛患者的预后价值。
76例平均年龄53±10岁、已有LBBB的患者接受了双嘧达莫静脉输注方案（0.56mg/kg）的锝-99m-甲氧基异丁基异腈灌注显像。负荷及静息单光子发射计算机断层扫描（SPECT）图像由2名经验丰富的核医学医师共同解读，并分为低风险扫描（正常心肌灌注扫描、小的可逆性/小的固定性缺损）和高风险扫描（大的、严重的、固定或可逆性缺损以及左心室腔扩大）。对患者进行了24±8个月的随访，并记录了严重心脏事件（梗死或心源性死亡）的发生情况。
76例患者中，52例（68%）为低风险扫描，其余24例（32%）为高风险扫描。在低风险组，发生1例（1.9%）心源性死亡和2例（3.8%）非致命性心肌梗死，而在高风险组，5例（20.8%）发生心源性死亡，3例（12.5%）发生非致命性心肌梗死。低风险组的总生存率为98.1%，高风险组为79.2%，差异有统计学意义（p=0.034）。正常心肌灌注显像对死亡发生的阴性预测值为100%。有或无胸痛患者的生存率无显著差异（p=0.31）。
双嘧达莫心肌灌注显像为LBBB患者提供了重要的预后信息；有助于根据心血管发病率和死亡率对患者进行分层，从而使临床医生能够提供早期治疗，尤其是对高风险患者。
