Background-Distinguishing pannus and thrombus in patients with prosthetic valve dysfunction is essential for the selection of proper treatment. We have investigated the utility of 64-slice multidetector computed tomography (MDCT) in distinguishing between pannus and thrombus, the latter amenable to thrombolysis. Methods and Results-Sixty-two (23 men, mean age 44±14 years) patients with suspected mechanical prosthetic valve dysfunction assessed by transesophageal echocardiography were included in this prospective observational trial. Subsequently, MDCT was performed before any treatment was started. Periprosthetic masses were detected by MDCT in 46 patients, and their attenuation values were measured as Hounsfield Units (HU). Patients underwent thrombolysis unless contraindicated, and those with a contraindication or failed thrombolysis underwent surgery. A mass which was completely lysed or surgically detected as a clot was classified as thrombus, whereas a mass which was surgically detected as tissue overgrowth was classified as pannus. A definitive diagnosis could be achieved in 37 patients with 39 MDCT masses (22 thrombus and 17 pannus). The mean attenuation value of 22 thrombotic masses was significantly lower than that in 17 pannus (87±59 versus 322±122; P<0.001). Area under the receiver operating characteristic curve was 0.96 (95% confidence interval: 0.91-0.99; P<0.001), and a cutoff point of HU≥145 provided high sensitivity (87.5%) and specificity (95.5%) in discriminating pannus from thrombus. Complete lysis was more common for masses with HU<90 compared with those with HU 90 to 145 (100% versus 42.1%; P=0.007). Conclusions-Sixty-four slice MDCT is helpful in identifying masses amenable to thrombolysis in patients with prosthetic valve dysfunction. A high (HU≥145) attenuation suggests pannus overgrowth, whereas a lower value is associated with thrombus formation. A higher attenuation (HU>90) is associated with reduced lysis rates. (Circ Cardiovasc Imaging. 2015;8:e003246.

Intravenous esmolol is safe and effective to reach the optimum heart rate in patients assigned for MSCT.

The presence and morphological characteristics of MB and its relation with atherosclerotic plaques in the involved coronary artery can be comprehensively analysed with 64-slice computed tomography coronary angiography. Atherosclerosis is a common finding in segments proximal to MB, but the prevalence of plaques in equivalent segments (proximal LAD in our study) is not higher than in patients under similar coronary artery disease risk and without MB. On the other hand, prevalence of atherosclerotic plaques at the distal LAD was significantly lower in our patients with MB on the middle LAD. Finally, we suggest that rather than causing proximal atherosclerosis, MB might have a more important role in the protection of distal segments of the bridged arteries from atherosclerosis.

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We have evaluated the prevalence of left main coronary artery disease (LMCAD) among patients referred to multislice computed tomography (MSCT) coronary angiography examinations. The study Group comprised of 1,000 consecutive patients (750 male and 250 female; mean age 53+/-12 years) who underwent successful 64-slice MSCT examinations. Left main coronary artery (LMCA) was classified into three Groups: normal LMCA; nonsignificant LMCAD with coronary plaques resulting in obstructions 50%. We have found that 24 patients (2.4%) had significant LMCAD. Additional 200 patients (20%) had nonsignificant LMCAD. Univariate analysis revealed that LMCAD was associated with age, male gender, diabetes, hypertension, hyperlipidemia, typical symptoms, history of previous myocardial infarction and previous percutaneous coronary intervention. Only age and male gender were found as independent predictors for LMCAD in multivariate analysis (P < 0.001 and P = 0.001, respectively,). Angiographic follow-up was avaliable for the 24 patients with significant LMCAD, and conventional coronary angiography confirmed the presence of significant LMCAD in all of these patients. Significant LMCAD was found in 2.4% of the 1,000 patients referred to 64-slice MSCT examinations. Age and male gender were the independent predictors for LMCAD.

Our results indicate that 64-slice computed coronary angiography is a reliable diagnostic modality for the detection of significant coronary artery stenosis in patients with sinus rhythm and scheduled to have CCA, but still has limitations of diagnostic performance on a per-segment and per-vessel basis.