Cardiology Division, Campo di Marte Hospital, Lucca, Italy.
Divisione di Cardiologia, Ospedale dell'Angelo, Mestre-Venezia, Italy.
J Am Soc Echocardiogr. 2014 Jul;27(7):742-8. doi: 10.1016/j.echo.2014.02.010. Epub 2014 Mar 26.
The prognostic value of Doppler-derived coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery in patients with type 2 diabetes with preserved left ventricular systolic function and without flow-limiting stenoses on angiography remains undetermined.
The study sample consisted of 144 patients with type 2 diabetes (82 men; mean age 62 ± 10 years) with chest pain or angina-equivalent symptoms, no histories of coronary artery disease, and echocardiographic ejection fractions ≥ 50%. All patients underwent dipyridamole stress echocardiography with CFVR assessment of the left anterior descending coronary artery by transthoracic Doppler echocardiography and coronary angiography showing normal coronary arteries or nonobstructive coronary artery disease.
Mean CFVR was 2.44 ± 0.57. On individual patient analysis, 109 patients (76%) had CFVR > 2, and 35 (24%) had CFVR ≤ 2. During a median follow-up period of 29 months (interquartile range, 14-44 months), 17 hard events (five deaths, 12 nonfatal myocardial infarctions) occurred. The annual hard-event rate was 13.9% in subjects with CFVR ≤ 2 and 2.0% in those with CFVR > 2. The annual event rate associated with CFVR ≤ 2 was significantly higher both in patients with left ventricular hypertrophy (P < .0001) and in those without left ventricular hypertrophy (P = .048). On Cox analysis, CFVR ≤ 2 (hazard ratio, 11.20; 95% confidence interval, 3.07-40.92), and male sex (hazard ratio, 7.80; 95% confidence interval, 1.74-34.97) were independent prognostic indicators, whereas nonobstructive coronary artery disease was not an independent predictor of outcomes.
Microvascular dysfunction before the occurrence of coronary artery involvement is a strong and independent predictor of outcomes in patients with type 2 diabetes. Vasodilator stress CFVR is a suitable tool to assess microvascular dysfunction in routine clinical practice.
左前降支冠状动脉血流储备（CFVR）的多普勒衍生值在伴有左心室收缩功能保留和冠状动脉造影无限制狭窄的 2 型糖尿病患者中的预后价值仍不确定。
研究样本包括 144 名患有 2 型糖尿病（82 名男性；平均年龄 62 ± 10 岁）、胸痛或等效心绞痛症状、无冠心病病史和超声心动图射血分数≥50%的患者。所有患者均接受双嘧达莫负荷超声心动图检查，通过经胸多普勒超声心动图评估左前降支冠状动脉的 CFVR，冠状动脉造影显示正常冠状动脉或非阻塞性冠心病。
平均 CFVR 为 2.44 ± 0.57。在个体患者分析中，109 名患者（76%）CFVR > 2，35 名患者（24%）CFVR ≤ 2。在中位数为 29 个月（四分位间距 14-44 个月）的中位随访期间，发生了 17 例硬终点事件（5 例死亡，12 例非致死性心肌梗死）。CFVR ≤ 2 的患者年硬终点发生率为 13.9%，CFVR > 2 的患者年硬终点发生率为 2.0%。CFVR ≤ 2 的患者发生事件的年发生率在伴有左心室肥厚的患者（P <.0001）和不伴有左心室肥厚的患者（P =.048）中均显著更高。在 Cox 分析中，CFVR ≤ 2（危险比，11.20；95%置信区间，3.07-40.92）和男性（危险比，7.80；95%置信区间，1.74-34.97）是独立的预后指标，而非阻塞性冠心病不是结局的独立预测因素。
在冠状动脉受累发生之前微血管功能障碍是 2 型糖尿病患者结局的一个强烈且独立的预测指标。血管扩张剂应激 CFVR 是评估常规临床实践中小血管功能障碍的合适工具。
