Analysis Imaging Features Of Amyloid Light Chain Myocardial Amyloidosis Diagonosed Clinically

Objective:To summarize and analyze results of laboratory examination and cardiac magnetic resonance imaging(CMR)of the patients with immunoglobulin light chain myocardial amyloidosis(AL-CA),compare the results of transthoracic echocardiography(TTE)and electrocardiogram(ECG)in patients with AL-CA,patients with hypertrophic cardiomyopathy(HCM)and normal people,provide reference for helping doctors diagnose AL-CA.Methods:From July 2014 to December 2019 in the first Hospital of Jilin University,41 patients with AL-CA,47 patients with HCM,and 132 normal healthy persons were enrolled in the retrospective study.(1)Summarized and analyzed the general clinical data and the laboratory examination results of 41 AL-CA patients.(2)CMR was performed in 9 of 41 patients with AL-CA and the imaging data were well preserved.the characteristics of CMR examination were summarized and analyzed in these patients.(3)Analyzed the TTE data of all enrolled patients by Kruskal-Wallis H nonparametric test and chi-square test.(4)Among 41 AL-CA patients,33 patients had complete ECG examination results,which were compared with those of 45 patients with HCM.The optimal threshold value(when the Yoden index was the largest)was found by using the ROC curve for dichotomizing measurement data,and then chi-square test was used to compare the differences of each indicator.(5)In 41 patients with AL-CA,15 patients with a medical history of hypertension or coronary heart disease and diabetes,were divided into two groups according to this characteristics.The optimal threshold value(when the Yoden index was the largest)was found by using the ROC curve for dichotomizing measurement data,then Chi-square test was used to compare the results of laboratory examination,diagnosis and liver and kidney involvement to find indicators with statistically significant differences.All results were obtained by the two-tailed method,and P<0.05 was considered as statistically significant.Results:(1)A total of 41 patients with AL-CA were included in this study,with a male to female incidence ratio of 2.7:1 and an average age of onset of 58 years.Among the light chain types,the lambda light chain type was the most common one(85.4%).According to the 2004 and2012 version of the Mayo staging diagnostic criteria,most patients were stage II at the time of diagnosis;and the incidence of renal involvement(58.5%)in the enrolled AL-CA patients was higher than that of the liver(12.2%).(2)Summarized the imaging characteristics of CMR in 9 patients with AL-CA: It was manifested as left ventricular subendocardial and/or ventricular septum perfusion defect or hypoperfusion at the first time of first-pass perfusion.The delayed enhancement of gadolinium contrast agent showed early emptying of gadolinium contrast medium,and "zebra sign" in interventricular septum and subendocardial left ventricular wall.The most common structural change of atrioventricular wall was thickened left ventricular wall and interventricular septum thickening and the most common functional changes are the decrease of left ventricular diastolic function.(3)Comparative analysis of TTE examination results: Comparison between the AL-CA group and the normal control group showed that statistically significant different in diameter of aortic root,diameter of left atrium anteroposterior,thickness of ventricular septal,thickness of left ventricular posterior wall,shortening fraction(FS%),ejection fraction(EF%)(P<0.05);However only LVEF,pericardial effusion and valve regurgitation were significantly different between the AL-CA group and the HCM group(P< 0.05).The TTE features of AL-CA could be manifested as: ventricular septal and left ventricular posteriorwall thickening were the most common structural changes,and left ventricular diastolic dysfunction(90.2%),valve regurgitation(70.7%)and pericardial effusion(68.3%).(4)Comparative analysis of ECG examination results: The ECG examination results of the AL-CA group and the HCM group were quite different include the heart rate,P-R interval,QRS,QT,QTC and ST-T changes.However in HCM group,correspounding the incidence of conduction block(P<0.05).In AL-CA group,limb lead low voltage was the most unique ECG result,The high incidence of T wave inversion in the corresponding lead was showed in the HCM group.(5)Comparing the result of laboratory examinations,echocardiographic examinations and related clinical characteristics between the two groups of AL-CA patients with or without previous history,only age and E/A had statistical sence.(P<0.05).Conclusions:(1)The characteristic manifestations of the CMR examination of AL-CA,first-pass perfusion could be manifested as perfusion defect or hypoperfusion,and delayed enhancement of gadolinium contrast agent could be manifested as early contrast agent emptying and subendocardial transmural enhancement.(2)The results of echocardiography and ECG between patients with AL-CA,HCM and normal healthy people were different.The TTE features of AL-CA could be manifested as:ventricular septal and left ventricular posterior wall thickening,Some of them may appear as“flashing signs”,and Left ventricular diastolic dysfunction in the early stage and systolic dysfunction in the later stage,and so on.ECG was characterized by low voltage in the limb leads in patent with AL-CA,The high incidence of T wave inversion in the corresponding lead was showed in the HCM group.(3)It could not affect the clinical diagnosis of AL-CA whether the patient was accompanied by a history of hypertension,diabetes,coronary heart disease,etc.