| BackgroundAtrial fibrillation(AF)has ability for formation of left side cardiac thrombi by loss of contraction of left appendage,predisposing them to increase the risk of subsequent systemic embolism(ischemic stroke).Theoretically,similar contractile functional abnormality on the right atrial appendage may also lead to the formation of the thrombi,and consequently the thrombi may travel into the pulmonary vascular system and pulmonary embolism(PE)happens.Due to the powerful compensation system of the lung,however,some of these right thrombi may be silent,and the risk of right appendage thrombus might be underestimated.On the other hand,it’s commonly accepted that 90%of symptomatic PE might arise from peripheral deep vein thrombosis(DVT).But no identification of DVT was found in 50%of patients of PE.Other sources should be considered in the lacking of peripheral DVT,especially in AF patients.However,the relationship between PE and AF has rarely been focused in the past studies.In addition,lots of studies has demonstrated that the CHADS2(congestive heart failure,hypertension,age>75 years,diabetes mellitus,previous stroke/TIA(transient ischemic attack)(double score))and CHA2DS2-VASc(congestive heart failure,age>75 years(double score),diabetes mellitus,previous stroke/TIA(double score),vascular disease,age 65-74 years,sex class(female))scores appeared to be a good prediction tool for the risk of stroke or systemic thromboembolism in AF,and CHA2DS2-VASc score showed better sensitivity for such risk prediction than CHADS2 score.However,few studies has been done for comparison of these two scoring systems on prediction of risk of PE.ObjectiveThis study is to evaluate the characteristics of PE patients with AF,especially the incidence of DVT in these patients.CHADS2 and CHA2DS2-VASc scores were further compared to see which one could be a better scoring system for the risk stratification of PE in AF patients.MethodologyIn this retrospective study,populations are patients who reported to The First Affiliated Hospital of Dalian Medical University and were diagnosed with AF and PE from 2002 to 2014.10540 patients were diagnosed with AF and 1709 were diagnosed with PE.A total of 110 patients were found when the patients with both AF and PE diagnosis confirmed.AF diagnosis was confirmed by 12-lead electrocardiography(ECG)or Holter,and PE diagnosis was considered to be confirm when there was clinical manifestation with combined objective confirmation test(by CT pulmonary angiogram(CTPA)or spiral computed tomography,perfusion-ventilation scan,high D-dimer>500 ug/l,low P02<80 and electrocardiographic signs(S1Q3T3).All demographic and clinical characteristics including potential risk factor for pulmonary embolism such as(DVT,active malignancy,history of recent surgery(previous 8 weeks),pulmonary diseases and smoking)were obtained at baseline.History of antithrombotic therapy was collected from the pharmacy database and discharge medical record.CHADS2 score(range 0-6)and CHA2DS2-VASc score(range 0-9)were calculated at study entry.For both CHADS2 and CHA2DS2-VASc scoring systems,patients were classified with scores<2 and>2 in low-intermediated and high risk groups,respectively,the difference between two risk stratification scoring systems were evaluated by each group.ResultsIn total 110 AF and PE patients,females were(49%),males were(51%)and mean age was(70.2±9.3).The incidence of PE in AF patients was 1.1%,whereas AF in PE patients was 6.4%.There were 76(69%)persistent and 34(31%)paroxysmal atrial fibrillation in these 110 patients.The proportion of potential risk factors of PE were DVT 26(23.6%),active malignant cancer 15(13.6%),recent surgery 11(10%)and 33(30%)patients had history of Pulmonary diseases.Smoking habits were present in 12(10.9%)patients.History of warfarin therapy taken was found in 16(14.5%)patients,among these patients only two of them were out of INR therapeutic range.The average proportion of INR(international normalized ratio),aPTT(activated partial thromboplastin time)and PT(Prothrombin time)for whole study were(1.4±0.5,31.9± 14.8 and 15.9±6.5).CHADS2 score was 0 in 17(15.4%)patients and 37(33.6%),20(18.1%),22(20%),8(7.2%),5(4.5%)and 1(0.9%)of patients had CHADS2 scores of 1,2,3,4,5 and 6 respectively,whereas CHA2DS2-VASc score was 0 in 4(3.6%)patients and 11(10%),24(21.8%),23(20.9),19(17.2%),16(14.5%),7(6.3%),5(4.5)and 1(0.9%)of patients had CHA2DS2-VASc scores of 1,2,3,4,5,6,7 and 8 respectively.According to CHADS2 and CHA2DS2-VASc scoring systems,group one(<2 points)low-intermediate risk were 54(49%)and 15(13.6%)number of patients while group two(≥ 2 points)high risk were 56(51%)and 95(83.3%)number of patients respectively.There was no difference in the proportion of the patients among CHADS2 score,low-intermediate risk and high risk groups[54(49%)vs.56(51%)].However,the proportion in low-intermediate risk group of the CHADS2 score was higher than the CHA2DS2-VASc[54(49%)vs.15(13.6%)].The proportion of high risk group[95(83.3%)vs.56(51%)]was significantly higher while that of low-intermediate risk group[15(13.6%)vs.54(49%)]was significantly lower as stratified by CHA2DS2-VASc score than by CHADS2 score(p<0.001).Among CHADS2 and CHA2DS2-VASc components,for age stratification a total of 29 patients(26.3%)were younger than 65 years(average age 58.2±5.8),42 patients(38%)were aged 65 to 74 years(average age 69.9±2.9),and 39 patients(35.4%)were 75 years or older(average age 79.5±4.1).Hypertension was most frequent component found in 59 patients(53.6%)and followed by 39(35.4%)of congestive heart failure patients.Diabetes mellitus was present in 13 patients(11.8%).A total of 26(22.8%)patients had history of vascular disease including prior myocardial infarction and coronary artery disease or aortic plaque.29(26.3%)patients were present with history of ischemic stroke/TIA(Transient ischemic attack).The proportion of ischemic stroke in the high risk group of CHADS2 was greater than CHA2DS2-VASc(51.7 vs.30.5%).However the mean CHA2DS2-VASc score for ischemic stroke was higher than mean CHADS2 score(4.8±1.6 vs.3.3±1.0).Conclusions1.In PE patients with AF,the prevalence of DVT was extremely low as compared to common PE population,which suggested that much of the thrombi might not originated from the deep vein but the right atria due to its loss of contraction under AF situation.2.In the PE patients with AF,there were 51%of them with CHADS2>2,whereas 86.4%of them with CHA2DS2-VASc>2,which means that the CHA2DS2-VASc scoring system might be more sensitive for the risk prediction of the PE in AF patients.3.Only 14.5%of these AF patients have taken warfarin when PE happened.Based on the fact that 51%of the patients with CHADS2>2 and 86.4%of them with CHA2DS2-VASc>2 indicated higher risk for PE,more patients should have taken the anticoagulation drugs.Much attention should be paid by the doctors for proper anticoagulation therapy under the risk stratification scores for AF patients. |
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