Joon-Won Kang

Isolated or predominant ocular motor nerve palsy as a manifestation of brain stem stroke.

Background and Purpose: There have been few reports of strokes producing isolated or predominant ocular motor nerve palsies as a clinical manifestation. Methods: We studied seven patients with brain stem stroke who had ocular motor palsies as the only or the predominant neurological manifestation, and we correlated their clinical features with radiological findings. Results: Five patients had small strokes in the area of oculomotor nuclei or fascicles and showed various combinations of oculomotor disturbances. Three of these patients showed vertical gaze paresis of the opposite eye. One patient with a small hemorrhage near the aqueduct of Sylvius showed fourth nerve palsy on the contralateral side, and a patient with a small infarct in the pontine tegmentum showed isolated sixth nerve palsy. Nonocular minor neurological signs included trigeminal sensory changes in four patients and clumsy arm in two. Ocular and nonocular dysfunctions generally improved within several months. Radiological findings of the brain stem correlated well with the ocular signs. Conclusions: We conclude that acute brain stem stroke should be included in the differential diagnosis of isolated ocular motor nerve palsies and that appropriate diagnostic investigations should be performed in these cases. (Stroke 1993;24:581‐586)

Comparison of radial artery patency according to proximal anastomosis site: Direct aorta to radial artery anastomosis is superior to radial artery composite grafting

OBJECTIVEnThe radial artery is frequently the second graft of choice after the left internal thoracic artery in coronary artery bypass graft surgery. However, the optimal radial artery proximal anastomosis site remains controversial. The aim of the present study was to compare the radial artery patency according to its use as either an aorta-radial artery graft or composite radial artery graft in coronary artery bypass grafting.nnnMETHODSnA total of 1735 patients received coronary artery bypass grafting using the radial artery between January 2001 and July 2007, of whom 893 received serial computed tomographic coronary angiographies; these patients formed the basis of the current study. The patients were divided into 2 groups: group I (direct radial artery to aortic anastomosis, n = 451 patients) and group II (radial artery composite grafting with the left internal thoracic artery, n = 442 patients). The number of distal radial artery anastomoses performed in group I was 657 and 749 in group II. Sequential bypassing was performed in 399 patients.nnnRESULTSnThe early patency rate was significantly higher in group I than in group II (98.3% vs 94.5%; P = .004). The 1-, 2-, and 5-year patency rates were also higher in group I than in group II (93.8% +/- 1.2%, 90.5% +/- 1.6%, and 74.3% +/- 6.1%, vs 90.5% +/- 1.4%, 85.3% +/- 1.9%, and 65.2% +/- 4.2%, respectively; P = .004). Multivariate analysis showed composite grafting (P = .02), the degree of target vessel stenosis <90% (P = .001), and the target revascularization site (P = .005) to be significant risk factors for occlusion.nnnCONCLUSIONnThe results of the current data showed superior early and late patency rates of coronary artery bypass grafting with radial artery to aorta anastomosis compared with left internal thoracic artery-radial artery composite grafting.

Long-Term Prognostic Value of Coronary CT Angiography in Asymptomatic Type 2 Diabetes Mellitus

OBJECTIVESnThis study sought to evaluate the long-term prognostic value of coronary computed tomography angiography (CTA) in asymptomatic patients with type 2 diabetes mellitus.nnnBACKGROUNDnThere are limited data on the long-term prognostic impact of coronary CTA in asymptomatic patients with type 2 diabetes mellitus.nnnMETHODSnThis study analyzed clinical outcomes of 591 consecutive asymptomatic patients with type 2 diabetes mellitus who underwent coronary CTA (mean age 62.2 ± 8.3 years and 352 men [59.6%]). A cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, orxa0late coronary revascularization. Patients were categorized into 3 groups according to severity of coronary artery disease (CAD) on coronary CTA: normal coronary arteries, nonobstructive CAD (<50%), and obstructive CAD (≥50%).nnnRESULTSnOne hundred sixty-eight patients (28.4%) had normal coronary arteries, whereas 236 (39.9%) patients had nonobstructive CAD and 187 (31.6%) had obstructive CAD. During the follow-up period (median 5.3 years [interquartile range: 4.7 to 5.8 years]), 37 cardiac events occurred in 29 patents: 10 cardiac deaths, 2 nonfatal myocardial infarctions, 8xa0cases of unstable angina, and 17 late coronary revascularizations. The 6-year event-free survival rates were 99.3 ± 0.7% in patients with normal coronary arteries, 96.7 ± 1.2% in patients with nonobstructive CAD, and 86.2 ± 3.0% in patients with obstructive CAD (log-rank pxa0< 0.001).nnnCONCLUSIONSnAsymptomatic patients with type 2 diabetes mellitus with normal coronary arteries or nonobstructive CAD on coronary CTA show excellent clinical outcomes over a follow-up period of more than 5 years, whereas prognosis is worse in patients with obstructive CAD. These findings suggest long-term prognostic value of coronary CTA for asymptomatic type 2 diabetes mellitus.

Late improvement in graft patency after coronary artery bypass grafting: Serial assessment with multidetector computed tomography in the early and late postoperative settings

OBJECTIVEnGrafts initially showing poor patency after coronary artery bypass grafting have occasionally shown improvement on serial multidetector computed tomography. This study analyzed possible factors associated with this phenomenon.nnnMETHODSnBetween September 2003 and July 2007, 512 patients underwent multidetector computed tomography within 1 month of isolated coronary artery bypass grafting. Among them, 1720 distal anastomoses were made with 1042 arterial and 302 venous conduits. Of these, 95 grafts (in 73 patients) were faint (n = 67) or nonvisualized (n = 28). Seventy-three of these grafts (in 56 patients) had follow-up multidetector computed tomographic evaluation 1 year after surgery and comprised the study group.nnnRESULTSnImprovement in graft patency (faint to patent or nonvisualization to visualization) occurred in 44 grafts (60.3%). Multivariate analysis revealed proximal target vessel stenosis of at least 90% (relative risk, 3.81; P = .009), larger target coronary size (relative risk, 1.72; P = .002), and radial artery graft use (relative risk, 4.44; P = .003) to be significantly associated with the graft patency restoration. Graft patency restoration was most commonly observed in a group of 28 radial artery grafts that were anastomosed to target vessel with proximal stenosis of at least 90%; of these grafts, 24 (85.7%) showed improved graft patency on follow-up.nnnCONCLUSIONSnA large proportion of radial artery grafts initially showing poor opacification after coronary artery bypass grafting demonstrated patency restoration on serial multidetector computed tomography. Larger target vessel size and target vessel stenosis of at least 90% were significant correlative factors.

Multiple Coronary Arteriovenous Fistulas to the Coronary Sinus With an Unruptured Coronary Sinus Aneurysm and Restrictive Coronary Sinus Opening to the Right Atrium

A 37-year-old woman was transferred to our department for surgery. She had experienced intermittent chest discomfort or pain and palpitation during the last 4 years. Chest radiographs showed cardiomegaly (cardiothoracic ratio 0.63). A preoperative ECG showed normal sinus rhythm (Figure 1). Echocardiography showed marked dilatation of the coronary sinus with an intramural thrombus and flow acceleration at its opening (Figure 2). Cardiac catheterization showed no significant coronary artery stenosis but revealed coronary arteriovenous fistulas (CAVFs) from the distal right coronary artery, distal left anterior descending artery, and proximal left circumflex artery draining directly into the coronary sinus (Figure 3). A preoperative computed tomography scan showed a large aneurysm that contained thrombi with a maximal diameter of 73 mm at the outer side of the left ventricular inferior wall (Figure 4). The site of the aneurysm coincided with the coronary sinus and greater cardiac vein. The computed tomography scan was unable to reveal drainage of the thrombosed aneurysm into the right atrium (RA). Magnetic resonance imaging, however, showed a pinpoint opening from the coronary sinus aneurysm to the RA (Figure 5). The right coronary artery was diffusely dilated and was connected to the coronary sinus after forming a small coronary artery aneurysm. Distal collateral vessels from the left anterior descending artery and left circumflex artery were connected directly to the coronary sinus (Figure 6). On …

Incremental Value of Subtended Myocardial Mass for Identifying FFR-Verified Ischemia Using Quantitative CT Angiography: Comparison With Quantitative Coronary Angiography and CT-FFR

OBJECTIVESnThis study examined the incremental value of subtended myocardial mass (Vsub) as assessed by coronary computed tomography angiography (CTA) for identifying lesion-specific ischemia verified by invasive fractional flow reserve (FFR) in quantitative coronary CTA.nnnBACKGROUNDnFFR is determined not only by coronary stenosis severity, but also by Vsub. One-step evaluation of combined Vsub and coronary lesion morphology may improve the accuracy of coronary CTA for identifying ischemia-producing lesions.nnnMETHODSnA total of 246 intermediate coronary artery lesions (30% to 80% diameter stenosis) in 220 patients (meanxa0age 61.7 years, 168 men) interrogated by FFR were retrospectively studied. Coronary CTA data were used to assess the Vsub by coronary artery stenosis, minimal lumen area (MLA), percentage of aggregated plaque volume (%APV), positive remodeling, and low-attenuation plaque. The ability of Vsub/MLA2 to discriminate lesions with FFRxa0≤0.80 was examined. Diagnostic performance, odds ratios, and category-less net reclassification improvements of coronary CTA parameters for FFR-verified (≤0.80) ischemia were evaluated. On-site computed tomography (CT) derived-FFR (CT-FFR) and quantitative coronary angiography (QCA) data were also compared.nnnRESULTSnOf 246 lesions, 84 (34.1%) showed an FFRxa0≤0.80. Vsub was independently associated with an FFRxa0≤0.80 (odds ratio: 1.04/1 cm3; pxa0= 0.032) and showed incremental value over MLA. Vsub/MLA2 >4.16 was the best single parameter for discriminating an FFRxa0≤0.80 with 83.3% sensitivity and 67.9% specificity. The area under the curve (AUC) of Vsub/MLA2 >4.16 (0.80 [95% confidence interval: 0.75 to 0.85]) was better than that of MLA (change in [Δ]AUC: 0.069; pxa0< 0.001), %APVxa0(ΔAUC: 0.096; pxa0= 0.017), and diameter stenosis of QCA (ΔAUC: 0.080; pxa0= 0.037) and was comparable to that of CT-FFR (AUC 0.77; ΔAUC: 0.035; pxa0= 0.304).nnnCONCLUSIONSnVsub is an independent determinant of an FFRxa0≤0.80. The mathematical index of Vsub/MLA2 >4.16 assessed by coronary CTA shows better diagnostic performance for the detection of ischemia-producing lesions thanxa0CT-derived MLA alone or %APV and QCA parameters and was comparable to that of on-site CT-FFR.

Rationale and design of the worldwide prospective multicenter registry on radiation dose estimates of cardiac CT angiography in daily practice in 2017 (PROTECTION VI)

BACKGROUNDnCardiac computed tomography angiography (cardiac CTA) is an increasingly used versatile imaging method to evaluate coronary and cardiac morphology. Owing to improvements in technology, image quality has continuously improved over the last 10-20 years. At the same time, numerous non-randomized and randomized studies have been performed to reduce the associated radiation exposure. Currently, it is unclear if the advances in technology and knowledge about radiation reduction translated into reduced levels of cardiac CTA radiation dose in daily clinical practice as well as a wide utilization of dose-saving strategies.nnnMETHODSnThe PROTECTION VI study is a multicenter, prospective, worldwide registry designed to evaluate radiation dose exposure, utilization of dose-saving strategies and diagnostic image quality during cardiac CTA in current daily practice. Assessment of image quality will be addressed by the evaluation of diagnostic image quality at the local study site and the calculation of quantitative image quality parameters in an imaging core laboratory. Above 4000 patients will be enrolled from approximately 70 sites in Europe, North America, South America, Asia and Australia. The study will analyze median radiation dose levels, image quality, frequency of use and efficacy of algorithms for dose reduction, and patient and study-related predictors associated with radiation dose.nnnCONCLUSIONSnThe PROTECTION VI study is designed to provide a reliable estimate of current radiation dose for cardiac CTA and to assess the potential for additional dose reductions.

Quantified degree of eccentricity of aortic valve calcification predicts risk of paravalvular regurgitation and response to balloon post-dilation after self-expandable transcatheter aortic valve replacement

BACKGROUNDnLimited data exist regarding the impact of aortic valve calcification (AVC) eccentricity on the risk of paravalvular regurgitation (PVR) and response to balloon post-dilation (BPD) after transcatheter aortic valve replacement (TAVR). We investigated the prognostic value of AVC eccentricity in predicting the risk of PVR and response to BPD in patients undergoing TAVR.nnnMETHODSnWe analyzed 85 patients with severe aortic stenosis who underwent self-expandable TAVR (43 women; 77.2±7.1years). AVC was quantified as the total amount of calcification (total AVC load) and as the eccentricity of calcium (EoC) using calcium volume scoring with contrast computed tomography angiography (CTA). The EoC was defined as the maximum absolute difference in calcium volume scores between 2 adjacent sectors (bi-partition method) or between sectors based on leaflets (leaflet-based method).nnnRESULTSnTotal AVC load and bi-partition EoC, but not leaflet-based EoC, were significant predictors for the occurrence of ≥moderate PVR, and bi-partition EoC had a better predictive value than total AVC load (area under the curve [AUC]=0.863 versus 0.760, p for difference=0.006). In multivariate analysis, bi-partition EoC was an independent predictor for the risk of ≥moderate PVR regardless of perimeter oversizing index. The greater bi-partition EoC was the only significant parameter to predict poor response to BPD (AUC=0.775, p=0.004).nnnCONCLUSIONnPre-procedural assessment of AVC eccentricity using CTA as bi-partition EoC provides useful predictive information on the risk of significant PVR and response to BPD in patients undergoing TAVR with self-expandable valves.

Feasibility of free-breathing diffusion tensor imaging in porcine acute myocardial infarction model

Background In vivo DT-MRI is challenging because the motion of the heart and respiration influence the parameters of diffusion tensor imaging, and the most of in vivo DT-MRI is performed under breath-hold. The purpose of this study was to evaluate the feasibility of in vivo DT-MRI without breath-hold with regard to changes in direction-dependent water diffusivity reflecting alterations in tissue integrity such as apparent diffusion coefficients (ADC), fractional anisotropy (FA), and fiber length.

Right ventricular functions measured by cardiac magnetic resonance imaging in patients who underwent tricuspid valve surgery: implication for patients’ outcome

Poster: ECR 2015 / C-1797 / Right ventricular functions measured by cardiac magnetic resonance imaging in patients who underwent tricuspid valve surgery: implication for patients’ outcome by: J.-W. Kang, W. J. Choi, D. H. Yang, T.-H. Lim; Seoul/KR