***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We determined the efficiency of a screening protocol based on coronary calcium scores ( CCS ) compared with exercise testing in patients with suspected coronary artery disease ( CAD ) , a normal ECG and troponin levels . Three-hundred- and -four patients were enrolled in a screening protocol including CCS by electron beam computed tomography ( Agatston score ) , and exercise testing . Decision-making was based on CCS . When CCS≥400 , coronary angiography ( CAG ) was recommended . When CCS<10 , patients were discharged . Exercise tests were grade d as positive , negative or nondiagnostic . The combined endpoint was defined as coronary event or obstructive CAD at CAG . During 12±4 months , CCS≥400 , 10–399 and < 10 were found in 42 , 103 and 159 patients and the combined endpoint occurred in 24 ( 57 % ) , 14 ( 14 % ) and 0 patients ( 0 % ) , respectively . In 22 patients ( 7 % ) , myocardial perfusion scintigraphy  was performed instead of exercise testing due to the inability to perform an exercise test . A positive , nondiagnostic and negative exercise test result was found in 37 , 76 and 191 patients , and the combined endpoint occurred in 11 ( 30 % ) , 15 ( 20 % ) and 12 patients ( 6 % ) , respectively . Receiver-operator characteristics analysis showed that the area under the curve of 0.89 ( 95 % CI : 0.85–0.93 ) for CCS was superior to 0.69 ( 95 % CI : 0.61–0.78 ) for exercise testing ( P<0.0001 ) . In conclusion , measurement of CCS is an appropriate initial screening test in a well-defined low-risk population with suspected CAD BACKGROUND Multidetector computed tomography ( MDCT ) has high diagnostic value for detecting or excluding coronary artery stenosis . We examined performance characteristics of MDCT for diagnosing or excluding an acute coronary syndrome in patients presenting to the emergency department ( ED ) with possible ischemic chest pain and examined relation to clinical outcome during a 15-month follow-up period . METHODS AND RESULTS We prospect ively studied 58 patients ( 56+/-10 years of age , 36 % female ) with chest pain possibly ischemic in origin and no new ECG changes or elevated biomarkers . The patients underwent 64-slice contrast-enhanced MDCT , which showed normal coronary vessels ( no or trivial atheroma ) in 15 patients , nonobstructive plaque in 20 ( MDCT-negative patients ) , and obstructive coronary disease ( > or = 50 % luminal narrowing ) in 23 ( MDCT-positive group ) . By further investigation ( new elevation of cardiac biomarkers , abnormal myocardial perfusion scintigraphy and /or invasive angiography ) , acute coronary syndrome was diagnosed in 20 of the 23 MDCT-positive patients ( ED MDCT sensitivity 100 % [ 20/20 ] , specificity 92 % [ 35/38 ] , positive predictive value 87 % [ 20/23 ] , negative predictive value 100 % [ 35/35 ] ) . During a 15-month follow-up period , no deaths or myocardial infa rct ions occurred in the 35 patients discharged from the ED after initial triage and MDCT findings . One patient underwent late  percutaneous coronary intervention ( late major adverse cardiovascular events rate , 2.8 % ) . Overall , ED MDCT sensitivity for predicting major adverse cardiovascular events ( death , myocardial infa rct ion , or revascularization ) during hospitalization and follow-up was 92 % ( 12/13 ) , specificity was 76 % ( 34/45 ) , positive predictive value was 52 % ( 12/23 ) , and negative predictive value was 97 % ( 34/35 ) . CONCLUSIONS We found that 64-slice cardiac MDCT is a potentially valuable diagnostic tool in ED patients with chest pain of uncertain origin , providing early direct noninvasive visualization of coronary anatomy . ED MDCT had high positive predictive value for diagnosing acute coronary syndrome , whereas a negative MDCT study predicted a low rate of major adverse cardiovascular events and favorable outcome during follow-up BACKGROUND Non-invasive coronary angiography by multislice spiral computed tomography ( MSCT ) is a promising method for the diagnosis of coronary artery disease ( CAD ) . However , the clinical role of this method has not been established for specific patient cohorts . Therefore , the objective of the current prospect i ve , blinded study was to investigate the diagnostic value of coronary MSCT angiography in patients with an intermediate pre-test probability for having CAD when compared with invasive angiography . METHODS AND RESULTS A total of 243 patients with an intermediate pre-test probability for having CAD were asked to undergo coronary 16- or 64-slice CT angiography before planned invasive angiography from 12 September 2003 to 13 July 2005 . The primary end point was defined as the diagnostic accuracy in the detection of significant coronary stenosis ( > or = 50 % lumen diameter reduction ) on a per-patient and an ' intention-to-diagnose'-based analysis . Secondary end points comprised per-artery and per segment-based analyses as well as the comparison of diagnostic accuracy of 16- vs. 64-slice MSCT angiography .  Of 243 enrolled patients , 129 and 114 patients were studied by 16- and 64-slice CT angiography  , respectively . The overall sensitivity , negative predictive value , and specificity for CAD detection by MSCT were 99 % ( 95 % CI , 94 - 99 % ) , 99 % ( 95 % CI , 94 - 99 % ) , and 75 % ( 95 % CI , 67 - 82 % ) , respectively . On a per-segment basis , the use of 64-slice CT was associated with significantly less inconclusive segments ( 7.4 vs. 11.3 % , P < 0.01 ) , result ing in a trend to an improved specificity ( 92 vs. 88 % , P = 0.09 ) . CONCLUSION In patients with an intermediate pre-test probability for having CAD this large , prospect i ve trial demonstrates that non-invasive coronary CT angiography is a very sensitive method for CAD detection . Furthermore , this method allows ruling out CAD very reliably and safely . Finally , 64-slice CT appears to be superior for CAD detection when compared with 16-slice CT STUDY OBJECTIVE  Coronary artery calcium scoring ( CACS )  is a simple and readily available test for identifying coronary artery disease . Our objective is to evaluate whether a CACS of zero will identify chest pain patients who can be safely discharged home , without need for further cardiac testing . METHODS This was a prospect i ve observational cohort study conducted at an urban tertiary care hospital of stable patients presenting to the emergency department ( ED ) with chest pain of uncertain cardiac cause . Patients with a normal initial troponin level , nonischemic ECG , and no history of coronary artery disease had stress myocardial perfusion imaging ( SPECT ) and CACS within 24 hours of ED admission . Cardiac events were defined as an acute coronary syndrome during the index hospitalization or in follow-up .  CACS results were assessed in relation to SPECT findings and cardiac events . RESULTS The 1,031 patients enrolled ( mean [ SD ] age 54 [ 13 ] years ) had a median CACS  of 0 ( 61 % with CACS of 0 ) . The frequency of an abnormal SPECT ranged from 0.8 % ( CACS of 0 ) to17 % ( CACS>400 ) . Cardiac events occurred in 32 patients ( 3.1 % ) during the index hospitalization ( N=28 ) or after hospital discharge ( N=4 ) ( mean 7.4 [ 3.3 ] months ) . Only 2 events occurred in 625 patients with a CACS of 0 ( 0.3 % ; 95 % confidence interval 0.04 % to 1.1 % ) . Thus , 2 of 32 patients with a cardiac event had a CACS of 0 ( 6 % ; 95 % confidence interval 0.8 % to 21 % ) . Both of these patients developed increased troponin levels during their index visit but had normal serial ECG and SPECT study results and no cardiac events at 6-month follow-up . CONCLUSION A majority of patients ( 61 % in our sample ) evaluated for chest pain of uncertain cardiac cause have a CACS of 0 , which predicts both a normal SPECT result and an excellent short-term outcome . Our results suggest that patients with a CACS of 0 can be discharged home , without further cardiac testing BACKGROUND The accuracy of multidetector computed tomographic ( CT ) angiography involving 64 detectors has not been well established . METHODS We conducted a multicenter study to examine the accuracy of 64-row , 0.5-mm multidetector CT angiography as compared with conventional coronary angiography in patients with suspected coronary artery disease . Nine centers enrolled patients who underwent calcium scoring and multidetector CT angiography before conventional coronary angiography .  In 291 patients with calcium scores of 600 or less , segments 1.5 mm or more in diameter were analyzed by means of CT and conventional angiography at independent core laboratories . Stenoses of 50 % or more were considered obstructive . The area under the receiver-operating-characteristic curve ( AUC ) was used to evaluate diagnostic accuracy relative to that of conventional angiography and subsequent revascularization status , whereas disease severity was assessed with the use of the modified Duke Coronary Artery Disease Index . RESULTS A total of 56 % of patients had obstructive coronary artery disease . The patient-based diagnostic accuracy of quantitative CT angiography for detecting or ruling out stenoses of 50 % or more according to conventional angiography revealed an AUC of 0.93 ( 95 % confidence interval [ CI ] , 0.90 to 0.96 ) , with a sensitivity of 85 % ( 95 % CI , 79 to 90 ) , a specificity of 90 % ( 95 % CI , 83 to 94 ) , a positive predictive value of 91 % ( 95 % CI , 86 to 95 ) , and a negative predictive value of 83 % ( 95 % CI , 75 to 89 ) . CT angiography was similar to conventional angiography in its ability to identify patients who subsequently underwent revascularization : the AUC was 0.84 ( 95 % CI , 0.79 to 0.88 ) for multidetector CT angiography and 0.82 ( 95 % CI , 0.77 to 0.86 ) for conventional angiography . A per-vessel analysis of 866 vessels yielded an AUC of 0.91 ( 95 % CI , 0.88 to 0.93 ) . Disease severity ascertained by CT and conventional angiography was well correlated ( r=0.81 ; 95 % CI , 0.76 to 0.84 ) . Two patients had important reactions to contrast medium after CT angiography . CONCLUSIONS Multidetector CT angiography accurately identifies the presence and severity of obstructive coronary artery disease and subsequent revascularization in symptomatic patients . The negative and positive predictive values indicate that multidetector CT angiography can not replace conventional coronary angiography at present . ( Clinical Trials.gov number , NCT00738218 . 
    Output:
    
There was a direct correlation with major cardiovascular events to higher calcium scores indicating that coronary artery calcium scores are strong predictors of the prognosis of coronary artery disease rather than angiographic findings .