Je Kyoun Shin

Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: comparison with cardiac magnetic resonance imaging and conventional coronary angiography

ObjectiveTo evaluate the feasibility and diagnostic accuracy of adenosine-stress dual-energy computed tomography (DECT) for detecting haemodynamically significant stenosis causing reversible myocardial perfusion defect (PD) compared with stress perfusion magnetic resonance imaging (SP-MRI) and conventional coronary angiography (CCA).MethodsFifty patients with known coronary artery disease (CAD) detected by dual-source CT (DSCT) were investigated by contrast-enhanced, stress DECT with high- and low-energy x-ray spectra settings during adenosine infusion. A colour-coded iodine map was used for evaluation of myocardial PDs compared with rest DSCT perfusion images. Reversible myocardial PDs according to the stress DECT/rest DSCT were compared with SP-MRI on a segmental basis and CCA on a vascular territorial basis.ResultsA total of 697 myocardial segments and 123 vascular territories of 41 patients were analysed. Three hundred one segments and 72 vascular territories in 38 patients showed reversible PDs on stress DECT. Stress DECT had 89% sensitivity, 78% specificity and 82% accuracy for detecting segments with reversible PDs seen on SP-MRI (n = 28). Compared with CCA (n = 41), stress DECT had 89% sensitivity, 76% specificity and 83% accuracy for the detection of vascular territories with reversible myocardial PDs that had haemodynamically relevant CAD.ConclusionAdenosine stress DECT can identify stress-induced myocardial PD in patients with CAD.

Diagnostic Performance of Combined Noninvasive Anatomic and Functional Assessment With Dual-Source CT and Adenosine-Induced Stress Dual-Energy CT for Detection of Significant Coronary Stenosis

OBJECTIVE The purpose of our study was to prospectively evaluate the incremental diagnostic value of combined dual-source coronary CT angiography (CTA) and CT myocardial perfusion imaging (MPI) for the detection of significant coronary stenoses. SUBJECTS AND METHODS Forty-five patients with known coronary artery disease detected by dual-source coronary CTA were investigated by adenosine-induced stress dual-source CTA and conventional coronary angiography. Analysis was performed in three steps: classification of coronary stenosis severity using dual-source coronary CTA, identification of myocardial perfusion defects using rest and stress CT MPI, and reclassification of coronary stenosis severity according to combined dual-source coronary CTA and CT MPI. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of dual-source coronary CTA before and after CT MPI were calculated on a per-vessel basis compared with conventional coronary angiography as the standard of reference. RESULTS Dual-source coronary CTA revealed 87 significantly stenotic vessels in 45 patients. Conventional coronary angiography revealed significant stenoses in 73 vessels in 42 patients. CT MPI showed myocardial perfusion defects in 81 vessel territories in 43 patients. After the CT MPI analysis, dual-source coronary CTA identified significant stenoses in 77 coronary vessels in 42 patients. Sensitivity, specificity, PPV, and NPV of the dual-source coronary CTA on a per-vessel basis before CT MPI were 91.8%, 67.7%, 73.6%, and 87.5%, respectively, and after CT MPI were 93.2%, 85.5%, 88.3%, and 91.4%, respectively. The area under the receiver operating characteristic curve increased significantly from 0.798 to 0.893 (p = 0.004). CONCLUSION Combined dual-source coronary CTA and CT MPI provides incremental diagnostic value compared with dual-source coronary CTA alone for the detection of significant coronary stenoses.

Myocardial Bridging of the Left Anterior Descending Coronary Artery: Depiction Rate and Morphologic Features by Dual-Source CT Coronary Angiography

Objective To evaluate the depiction rate and morphologic features of myocardial bridging (MB) of the left anterior descending coronary artery (LAD) using dual-source CT (DSCT). Materials and Methods CT scans from a total of 1,353 patients who underwent DSCT were reviewed retrospectively for LAD-MB. Seventy-eight patients were excluded due to poor image quality or poor enhancement of the coronary artery. The length and depth of the MB were analyzed and classified as superficial or deep with respect to the depth (≤ 1 or > 1 mm) of the LAD tunneled segment. Superficial MB was subdivided into complete or incomplete types according to full or partial encasement of the myocardium. Results Of the 1,275 patients included in this study, 557 cases of MB were found from 536 patients (42%). Superficial MB was observed in 368 of 557 (66%) cases, and deep MB was seen in 189 of 557 (34%) cases. Superficial MB showed 2 types: complete (128 of 368, 35%) and incomplete (240 of 368, 65%). The mean length of a tunneled segment for superficial MB was 16.4 ± 8.6 mm. The mean length and depth of a tunneled segment for deep MB were 27.6 ± 12.8 mm and 3.0 ± 1.4 mm, respectively. The incidence of atherosclerotic plaques in a 2-cm-long segment proximal to MB was 16%. Conclusion The depiction rate of LAD-MB using DSCT in a large series of patients was 42%, with two-thirds of MB segments being the superficial type.

Efficacy and Safety of Dexmedetomidine for Postoperative Delirium in Adult Cardiac Surgery on Cardiopulmonary Bypass

Background Delirium after cardiac surgery is associated with serious long-term negative outcomes and high costs. The aim of this study is to evaluate neurobehavioral, hemodynamic, and sedative characteristics of dexmedetomidine, compared with the current postoperative sedative protocol (remifentanil) in patients undergoing open heart surgery with cardiopulmonary bypass (CPB). Methods One hundred and forty two eligible patients who underwent cardiac surgery on CPB between April 2012 and March 2013 were randomly divided into two groups. Patients received either dexmedetomidine (range, 0.2 to 0.8 μg/kg/hr; n=67) or remifentanil (range, 1,000 to 2,500 μg/hr, n=75). The primary end point was the prevalence of delirium estimated daily via the confusion assessment method for intensive care. Results When the delirium incidence was compared with the dexmedetomidine group (6 of 67 patients, 8.96%) and the remifentanil group (17 of 75 patients, 22.67%) it was found to be significantly less in the dexmedetomidine group (p<0.05). There were no statistically significant differences between two groups in the extubation time, ICU stay, total hospital stay, and other postoperative complications including hemodynamic side effects. Conclusion This preliminary study suggests that dexmedetomidine as a postoperative sedative agent is as sociated with significantly lower rates of delirium after cardiac surgery.

Aortic Valve Reconstruction With Leaflet Replacement and Sinotubular Junction Fixation: Early and Midterm Results

BACKGROUND Aortic valve reconstruction surgery (AVRS), consisting of aortic leaflet reconstruction with tailored pericardial patches and fixation of the sinotubular junction with properly sized fabric rings, is performed for the treatment of aortic valve diseases. The early and midterm outcomes of AVRS were analyzed. METHODS Between December 2007 and December 2012, 262 patients with isolated aortic valve disease underwent AVRS in one center. Clinical outcomes, effective orifice area, mean gradients, and left ventricular mass index were evaluated yearly. RESULTS Mean follow-up duration was 36.0±17.1 months and was complete in 100% of surviving patients. There was no hospital mortality, but there were 3 late deaths (1.1% late mortality). Seven patients (2.7%) required reoperation: 5 because of endocarditis and 2 because of suture disruption of the leaflets. Ten patients (3.8%) experienced neurologic events. Aortic valve regurgitation was absent or trivial in 226 patients (87.3%) and mild in 29 (11.2%), mild to moderate in 3 (1.2%), and moderate to severe in 1 (0.4%). The mean valve gradient and valve orifice index were 10.6±5.3 mm Hg and 1.3±0.4 cm2/m2, respectively. CONCLUSIONS The data from the first 5 years after AVRS reveal good clinical and hemodynamic outcomes, suggesting that AVRS is a new alternative technique to the practice of replacement with stented bioprostheses and mechanical prostheses. However, whether the reconstructed aortic valve represents a truly long-term valve remains to be demonstrated.

Comparative analysis of thoracotomy and sternotomy approaches in cardiac reoperation.

Background Reoperation of cardiac surgery via median sternotomy can be associated with significant complications. Thoracotomy is expected to reduce the risk of reoperation and to enhance the surgical outcomes. We retrospectively analyzed two operative approaches (thoracotomy vs. sternotomy) in cardiac reoperation. Materials and Methods From September 2007 to December 2010, 35 patients who required reoperation of the mitral valvular disease following previous median sternotomy were included. Average age of patients was 45.8±15.4 years (range, 14 to 76 years) and male-to-female was 23:12. Interval period between primary operation and reoperation was 135.8±105.6 months (range, 3.3 to 384.9 months). Results Comparative analysis was done dividing the patient group into two groups that are thoracotomy group (22 patients) and sternotomy group (13 patients). Thoracotomy group was significantly lower in operative time (415.2±90.3 vs. 497.5±148.0, p<0.05), bleeding control time (108.0±29.5 vs. 146.4±66.8, p<0.05) and chest tube drainage (287.5±211.5 mL vs. 557.3±365.5 mL, p<0.05) compared to sternotomy group. Conclusion The thoracotomy approach is superior to sternotomy in some variables, and it is considered as a valid alternative to repeat median sternotomy in patients who underwent a previous median sternotomy.

Novel Early Predictor of Acute Kidney Injury after Open Heart Surgery under Cadiopulmonary Bypass Using Plasma Neutrophil Gelatinase-Associated Lipocalin

Background Open heart surgery using cardiopulmonary bypass (CPB) is considered one of the most frequent surgical procedures in which acute kidney injury (AKI) is a frequent and serious complication. The aim of the present study was to evaluate the efficiency of neutrophil gelatinase-associated lipocalin (NGAL) as an early AKI biomarker after CPB in cardiac surgery (CS). Methods Thirty-seven adult patients undergoing CS with CPB were included in this retrospective study. They had normal preoperative renal function, as assessed by the creatinine (Cr) level, NGAL level, and estimated glomerular filtration rate. Serial evaluation of serum NGAL and Cr levels was performed before, immediately after, and 24 hours after the operation. Patients were divided into two groups: those who showed normal immediate postoperative serum NGAL levels (group A, n=30) and those who showed elevated immediate postoperative serum NGAL levels (group B, n=7). Statistical analysis was performed using Statistical Package for the Social Sciences version 18. Results Of the 37 patients, 6 (6/37, 16.2%) were diagnosed with AKI. One patient belonged to group A (1/30, 3.3%), and 5 patients belonged to group B (5/7, 71.4%). Two patients in group B (2/7, 28.5%) required further renal replacement therapy. Death occurred in only 1 patient (1/37, 2.7%), who belonged to group B. Conclusion The results of this study suggest that postoperative plasma NGAL levels can be used as an early biomarker for the detection of AKI following CS using CPB. Further studies with a larger sample size are needed to confirm our results.

Aortic Valve Reconstruction with Use of Pericardial Leaflets in Adults with Bicuspid Aortic Valve Disease: Early and Midterm Outcomes

In this study, we retrospectively analyzed the outcomes of adults with bicuspid aortic valve (BAV) disease who underwent aortic valve reconstructive surgery (AVRS), consisting of replacement of the diseased BAV with 2 or 3 pericardial leaflets plus fixation of the sinotubular junction for accurate and constant leaflet coaptation. From December 2007 through April 2013, 135 consecutive patients (mean age, 49.2 ± 13.1 yr; 73.3% men) with symptomatic BAV disease underwent AVRS. Raphe was observed in 84 patients (62.2%), and the remaining 51 patients had pure BAV without raphe. A total of 122 patients (90.4%) underwent 3-leaflet reconstruction, and 13 (9.6%) underwent 2-leaflet reconstruction. Concomitant aortic wrapping with an artificial graft was performed in 63 patients (46.7%). There were no in-hospital deaths and 2 late deaths (1.5%); 6 patients (4.4%) needed valve-related reoperation. The 5-year cumulative survival rate was 98% ± 1.5%, and freedom from valve-related reoperation at 5 years was 92.7% ± 3.6%. In the last available echocardiograms, aortic regurgitation was absent or trivial in 116 patients (85.9%), mild in 16 (11.9%), moderate in 2 (1.5%), and severe in one (0.7%). The mean aortic valve gradient was 10.2 ± 4.5 mmHg, and the mean aortic valve orifice area index was 1.3 ± 0.3 cm(2)/m(2). The 3-leaflet technique resulted in lower valve gradients and greater valve areas than did the 2-leaflet technique. Thus, in patients with BAV, AVRS yielded satisfactory early and midterm results with low mortality rates and low reoperation risk after the initial procedure.

Short-term Mechanical Circulatory Support with a Centrifugal Pump - Results of Peripheral Extracorporeal Membrane Oxygenator According to Clinical Situation

Background A peripheral extracorporeal membrane oxygenator (p-ECMO) has been developed to support patients who are dying due to a serious cardiopulmonary condition. This analysis was planned to define the clinical situation in which the patient benefits most from a p-ECMO. Material and Methods Between June 2007 and Aug 2009, a total of 41 adult patients used the p-ECMO. There were 23 males and 18 females (mean age 54.4±15.1 years). All patients had very unstable vital signs with hypoxia and complex cardiac problems. We divided the patients into 4 groups. In the first group, a p-ECMO was used as a bridge to cardiac operation. In the second group, patients did not have the opportunity to undergo any cardiac procedures; nevertheless, they were treated with a p-ECMO. In the third group, patients mostly had difficulty in weaning from CPB (cardiopulmonary bypass) after cardiac operation. The fourth group suffered from many complications, such as pneumonia, bleeding, infections, and LV dysfunction with underlying cardiac problems. All cannulations were performed by the Seldinger technique or cutting down the femoral vessel. A long venous cannula of DLP® (Medtronic Inc, Minneapolis, MN) or RMI® (Edwards Lifesciences LLC, Irvine, CA) was used together with a 17~21 Fr arterial cannula and a 21 Fr venous cannula. As a bypass pump, a Capiox emergency bypass system (EBS®; Terumo, Tokyo, Japan) was used. We attempted to maintain a flow rate of 2.4~3.0 L/min/m2 and an activated clotting time (ACT) of around 180 seconds. Results Nine patients survived by the use of the p-ECMO. Ten patients were weaned from a p-ECMO but they did not survive, and the remainder had no chance to be weaned from the p-ECMO. The best clinical situation to apply the p-ECMO was to use it as a bridge to cardiac operation and for weaning from CPB after cardiac operation. Conclusion Various clinical results were derived by p-ECMO according to the clinical situation. For the best results, early adoption of the p-ECMO for anatomical correction appears important.

Organizing Thrombus Mimicking a Cardiac Tumor Located at the Mitral-Aortic Intervalvular Fibrosa

Thrombosis at the left ventricular outflow tract occurs without any detectable heart disease or predisposing factors only extremely rarely. A 48-year-old male visited Konkuk University Medical Center with loss of consciousness one month prior to presentation. Before he visited our hospital, he had been diagnosed with a cardiac tumor, which was located between the left atrium and posterior aortic root, and which was adjacent to both the aortic and mitral valves. Cardiac transplantation was recommended at the other hospital because of the high risk of cardiac dysfunction induced by both aortic and mitral valvular dysfunction after surgical resection. Based on preoperative transthoracic echocardiography, cardiac computed tomography, cardiac magnetic resonance imaging, and intra-operative transesophageal echocardiography, we considered it to be a benign tumor. Complete resection was achieved and the pathology confirmed organizing thrombus. We report a case of organizing thrombus mimicking a cardiac tumor, which was located at the mitral-aortic intervalvular fibrosa of the left ventricular outflow tract without any heart disease.