The Preoperative Non-invasive Screening Of CAD In Patients With Rheumatic Mitral Valve Disease

It is of great importance to detect the presence of coexistent coronary artery disease(CAD) before operations on heart valves because of the impact of untreated CAD onperioperative and long-term post-operative survival. According to the American heartassociation and the American heart College (AHA/ACC) related guidelines, coronaryangiography was recommend before the mitral valve operation for patients,who aregreater than35year old male, women more than35years old and has coronary heartdisease risk factors or already menopause.Accurate identification by coronaryangiography (CAG) for every patient is not wise due to the low positive rate, thepossible complications, and the cost. It is become focus in clinical or scientificresearch to find a safe, noninvasive, effective and simple process used in preoperativefor screening CAD. In order to reduce unnecessary selective coronary angiography,this study conducted two part to discuss.First part Objectives: This study aims to develop a Logistic regression modeland a simple score system for the prediction of significant coronary artery disease(CAD) in patients undergoing operations for rheumatic mitral valve disease.Methods:A total of1241rheumatic patients (mean age57±6yrs) who underwent routinecoronary angiography before mitral valve operations between1998and2009wereanalyzed. To identify low-risk (≤5%) patients, a bootstrap refined logistic regressionmodel on the basis of clinical risk factors was developed, from which an additivemodel was derived. Receiver operating characteristic (ROC) curves were used tocompare discrimination and precision was quantified by the Hosmer-Lemeshowstatistic. Significant coronary atherosclerosis was defined as50%or more luminalnarrowing in one or more major epicardial vessels by means of coronaryangiography.Results: One hundred twenty-seven (10.2%) patients had significant coronary atherosclerosis. Independent predictors of significant CAD include age, malesex, hypertension, angina, smoking, and hypercholesterolemia. Five hundred and fiftypatients were designated as low risk according to our logistic regression and additivemodels. Of these patients, only6(1.1%) had single-vessel disease, and none hadmultivessel disease. Our models proved more efficient than established regressionmodels. Conclusions: Our logistic regression model could estimate the risk ofsignificant CAD in rheumatic patients undergoing mitral valve operations, while theadditive simple score system could reliably identify the low-risk patients in whomroutine preoperative angiography might be safely avoided.Second part Objective To evaluate the diagnostic accuracy of320-detectorrow CT coronary angiography in patients with atrial fibrillation (AF) undergoingoperations for rheumatic mitral valve disease.Methods Thirty-five patients withpersistent AF undergoing operations for rheumatic mitral valve disease wereenrolled.All patients underwent both CTCA and conventional coronary angiography(CCA)before the mitral valve operations. CT image quality (good、moderate、poor)and significant stenosis(≥50%)were evaluated by two attending physicians of Cardiacsurgery,who both blinded to the results of CCA. Pearson’s correlation analysis wasperformed to compare image quality with mean heart rate.The sensitivity, specificity,positive predictive value(PPV) and negative predictive value (NPV) were calculatedby using conventional coronary angiography as the reference standard. Agreements indetection of coronary artery stenosis between320-detector CTCA and CCA wereevaluated with kappa statistics.Results The mean heart rate was94.7±21.4beats/min.There was highly significant correlation between mean heart rate and imagequality.For RCA(r=0.554， P=0.002),CM(r=0.559， P=0.016)。 On segment-basedanalysis, sensitivity, specificity, PPV and NPV were87.50%,99.4%,82.4%and99.6%. On vessel-based analysis, sensitivity, specificity, PPV and NPV were87.5%,97.6%,82.4%and98.4%. On patient-based analysis, sensitivity, specificity, PPV andNPV were84.6%,86.3%,78.6%and90.5%.The kappa statistics respectivelywere0.843、0.828and0.700.The agreement of Interobserver was0.770. Conclusion320-detector CTCA can be taken as the first chose to screen CAD in patients with AFundergoing operations for rheumatic mitral valve disease，because of accuracy inexcluding CAD.Summary: Our logistic regression model could estimate the risk of significant CADin rheumatic patients undergoing mitral valve operations.And the low-risk patients cansuccessfully used to spare unnecessary exposure to invasive coronaryangiography.320-detector rows computed tomography can morphologically identifycoronary lesions.And the diagnostic accuracy of CTCA in patients with atrialfibrillation (AF) undergoing operations for rheumatic mitral valve disease is good.Undoubtedly,320-slice row computed tomography as an noninvasive coronaryangiography can effectively decrease possible complications and economic burden.