血清游离轻链检测在心肌淀粉样变性患者中的预后价值

The prognostic value of baseline serum free light chain in cardiac amyloidosis

目的 探讨血清游离轻链（sFLC）检测在轻链型（AL型）心肌淀粉样变性患者中的预后价值.方法 收集我院2013年1月-2015年1月收治的27例AL型心肌淀粉样变性患者,采集一般临床资料、心脏超声和心电图检查参数,并采用免疫比浊法检测sFLC.将患者中受累轻链（即克隆轻链）和非受累轻链的差值（dFLC）≤307 mg/L的患者归为低dFLC组（13例）,dFLC＞ 307 mg/L患者归为高dFLC组（14例）,评估两组患者的预后.结果 高dFLC组舒张早期二尖瓣血流速度与舒张晚期二尖瓣血流速度比值（E/A》 ＞2患者比例明显高于低dFLC组（71.4％比30.8％,P=0.035）,低dFLC组患者生存时间比高dFLC组长（中位生存时间17个月比3个月,P=0.004）.若依据Mayo2012分期,选择dFLC=180 mg/L为界点,将患者重新分为高低dFLC两组并进行Kaplan-Meier生存分析,患者dFLC≤180 mg/L生存时间仍然较高dFLC长（中位生存时间17个月比4个月,P=0.014）.若根据∥λ比值分组,分别取κ型和λ型患者所测得的κ/λ比值中位数为界点,将κ型sFLC-ratio≤19.6和λ型sFLC-ratio＞0.065归为低sFLC-ratio组;将sFLC-ratio＞ 19.6和λ型sFLC-ratio≤0.065归为高sFLC-ratio组.对重新定义的两组进行生存分析,低sFLC-ratio组生存时间仍然较高sFLC-ratio组长（中位生存时间17个月比4个月,P=0.023）.采用Cox比例风险模型进行多变量分析,dFLC和心功能纽约心脏协会（NYHA）分级是影响患者生存的两个风险因素,其中高dFLC（dFLC＞ 307 mg/L）的死亡风险是低dFLC（dFLC≤307 mg/L）的4.28倍（95％CI1.55～11.8,P=0.005）.结论 sFLC能够初步提示AL型心肌淀粉样变性的预后.

Objective To analyze the prognostic value of baseline serum free light chain （sFLC） in light-chain （AL） cardiac amyloidosis.Methods Twenty-seven patients with AL cardiac amyloidosis were retrospectively reviewed from January 2014 to January 2015.sFLC was measured by immuoturbidimetric assay.Baseline characteristics,echocardiographic parameters and electrocardiogram data were analyzed.According to the median baseline dFLC （involved sFLC minus uninvolved sFLC）,patients were categorized into either the low dFLC（≤307mg/L） or the high dFLC group （〉307mg/L）.Results More subjects in the high dFLC group with early/late diastolic mitral velocity ratio （E/A ratio） over 2 （71.4% vs 30.8%,P =0.035）,and subjects in this group had a shorter median survival time than those in the low dFLC group （3 months vs 17 months,P =0.004）.A similar phenomenon for median survival time was observed when the subjects were redivided either by a new cut-off value of 180mg/L for dFLC （low dFLC group：17 months;high dFLC group：4 months,P =0.014） or a κ/λ ratio,in which subjects with κ type sFLC-ratio ≤ 19.6 and λ type sFLC-ratio 〉0.065 were in the low sFLC-ratio group （17 months） and those with κ type sFLC-ratio 〉 19.6 and λ type sFLC-ratio ≤0.065 were in the high sFLC-ratio group （4 months,P=0.023）.In multivariate analysis,dFLC and New York Heart Association （NYHA） classification of cardiac function were two risk factors associated with all-cause mortality in patients,among which the hazard ratio for higher dFLC was 4.28 （95% CI 1.55-11.8,P =0.005）.Conclusion The level of sFLC could be a marker for the prognosis of AL cardiac amyloidosis.