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BACKGROUND: Fractional flow reserve (FFR) has become an established tool for guiding treatment, but its graded relationship to clinical outcomes as modulated by medical therapy versus revascularization remains unclear.OBJECTIVES: The study hypothesized that FFR displays a continuous relationship between its numeric value and prognosis, such that lower FFR values confer a higher risk and therefore receive larger absolute benefits from revascularization.METHODS: Meta-analysis of study- and patient-level data investigated prognosis after FFR measurement. An interaction term between FFR and revascularization status allowed for an outcomes-based threshold.RESULTS: A total of 9,173 (study-level) and 6,961 (patient-level) lesions were included with a median follow-up of 16 and 14 months, respectively. Clinical events increased as FFR decreased, and revascularization showed larger net benefit for lower baseline FFR values. Outcomes-derived FFR thresholds generally occurred around the range 0.75 to 0.80, although limited due to confounding by indication. FFR measured immediately after stenting also showed an inverse relationship with prognosis (hazard ratio: 0.86, 95% confidence interval: 0.80 to 0.93; p < 0.001). An FFR-assisted strategy led to revascularization roughly half as often as an anatomy-based strategy, but with 20% fewer adverse events and 10% better angina relief.CONCLUSIONS: FFR demonstrates a continuous and independent relationship with subsequent outcomes, modulated by medical therapy versus revascularization. Lesions with lower FFR values receive larger absolute benefits from revascularization. Measurement of FFR immediately after stenting also shows an inverse gradient of risk, likely from residual diffuse disease. An FFR-guided revascularization strategy significantly reduces events and increases freedom from angina with fewer procedures than an anatomy-based strategy.

Radiation exposure of the operator during cardiac catheter ablation procedures was assessed for an experienced cardiologist adopting various measures of radiation protection and utilised electroanatomic navigation. Chip thermoluminescent dosemeters were placed at the eyes, chest, wrists and legs of the operator. The ranges of fluoroscopy time and air kerma area product values associated with cardiac ablation procedures were wide (6.3-48.3 min and 1.7-80.3 Gy cm. 2, respectively). The measured median radiation doses per procedure for each monitored position were 23.6 and 21.3 μSv to the left and right wrists, respectively, 25.3 and 30.4 μSv to the left and right legs, respectively. The doses to the eyes were below the minimum detectable dose of 9 μSv. The estimated median effective dose was 22.5 μSv. Considering the actual workload of the operator, the calculated annual doses to the hands, legs and eyes, as well as the annual effective dose, were all below the corresponding limits. The findings of this study indicate that cardiac ablation procedures performed at a modern laboratory do not impose a high radiation hazard to the operator when radiation protection measures are routinely adopted. © The Author 2012. Published by Oxford University Press. All rights reserved.

Background: The ideal bifurcation stenting technique is not established, and data on the hemodynamic characteristics at stented bifurcations are limited. Methods and Results: We used computational fluid dynamics analysis to assess hemodynamic parameters known affect the risk of restenosis and thrombosis at coronary bifurcations after the use of various single- and double-stenting techniques. We assessed the distributions and surface integrals of the time averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (r). Single main branch stenting without side branch balloon angioplasty or stenting provided the most favorable hemodynamic results (integrated values of TAWSS=4.13·10-4 N, OSI=7. 52·10-6 m2, r=5.57·10 -4 m2/Pa) with bifurcational area subjected to OSI values >0.25, >0.35, and >0.45 calculated as 0.36 mm2,0.04 mm 2, and 0 mm2, respectively. Extended bifurcation areas subjected to these OSI values were seen after T-stenting: 0.61 mm2, 0.18 mm 2, and 0.02 mm2, respectively. Among the considered double-stenting techniques, crush stenting (integrated values of TAWSS=1.18·104 N, OSI=7.75·10-6 m 2, r=6.16·10-4 m2/Pa) gave the most favorable results compared with T-stenting (TAWSS=0.78·10 -4 N, OSI=10.40·10-6 m2, r=6.87·10-4μm2/Pa) or the culotte technique (TAWSS=1.30· 10-4 N,OSI=9.87·10-6 m2, r=8.78·10-4 m2/Pa). Conclusions: In the studied models of computer simulations, stenting of the main branch with our without balloon angioplasty of the side branch offers hemodynamic advantages over double stenting. When double stenting is considered, the crush technique with the use of a thin-strut stent may result in improved immediate hemodynamics compared with culotte or T-stenting. © 2012 American Heart Association, Inc.

Objective: To derive a model for the identification of left anterior descending (LAD) coronary artery stenoses predisposed to plaque rupture and thrombosis. Methods: Coronary angiograms of 186 consecutive patients (original sample) with an anterior ST elevation myocardial infarction (STEMI) and a recanalized LAD were reconstructed in the three-dimensional space. Culprit lesions were compared with 293 stable LAD coronary stenoses on the same patients. A model for predicting stenoses with a high probability of thrombosis was derived and validated in 50 subsequent patients with STEMI, and 50 patients with stable lesions (validation sample). Results: The majority of culprit lesions occurred between 20 and 40 mm from the LAD ostium, whereas the majority of stable lesions were found in a distance of more than 60 mm (P

Catheter ablation is an established therapeutic option for certain patients with atrial fibrillation (AF), but the reported success rates of anatomically oriented ablation techniques are low compared with those for other ablation indications, particularly for persistent AF. Electrophysiologically oriented ablation techniques have emerged over the last decade that aim at modifying the arrhythmogenic substrate to the extent that it cannot maintain fibrillatory activity. Electrogram-guided ablation procedures are the most common substrate-targeted ablation approaches and can be broadly divided into procedures that target atrial sites with particular electrogram characteristics in either the time domain (complex fractionated electrograms) or frequency components in the frequency domain (dominant frequencies). The concept of electrogram-based catheter ablation of AF by identifying complex fractionated electrograms and dominant frequency sites is valid only if these sites are temporally stable. © 2011 Expert Reviews Ltd.

Flow patterns may affect the potential of thrombus formation following plaque rupture. Computational fluid dynamics (CFD) were employed to assess hemodynamic conditions, and particularly flow recirculation and vortex formation in reconstructed arterial models associated with ST-elevation myocardial infraction (STEMI) or stable coronary stenosis (SCS) in the left anterior descending coronary artery (LAD). Results indicate that in the arterial models associated with STEMI, a 50% diameter stenosis immediately before or after a bifurcation creates a recirculation zone and vortex formation at the orifice of the bifurcation branch, for most of the cardiac cycle, thus allowing the creation of stagnating flow. These flow patterns are not seen in the SCS model with an identical stenosis. Post-stenotic recirculation in the presence of a 90% stenosis was evident at both the STEMI and SCS models. The presence of 90% diameter stenosis resulted in flow reduction in the LAD of 51.5% and 35.9% in the STEMI models and 37.6% in the SCS model, for a 10 mmHg pressure drop. CFD simulations in a reconstructed model of stenotic LAD segments indicate that specific anatomic characteristics create zones of vortices and flow recirculation that promote thrombus formation and potentially myocardial infarction. © 2010 Institute of Physics and Engineering in Medicine.

BACKGROUND: The mechanisms involved in the pathogenesis of coronary artery ectasia (CAE) have not been elucidated. Circulating antiendothelial cell antibodies (AECA) are often detectable in systemic vasculitis and have been implicated in the pathogenesis of endothelial injury. Their prevalence in CAE is not known. METHODS AND Results: Out of 475 consecutive patients subjected to coronary angiography, 27 patients were diagnosed with CAE. Thirty patients matched for age, body mass index, sex, and coronary artery disease prevalence, served as controls. Serum AECA of IgG, IgM, and IgA isotypes were detected using a cell-based enzyme-linked immunosorbent assay (ELISA). Antinuclear antibodies (ANA) and antineutrophil cytoplasmic antibodies (ANCA) were detected using indirect immunofluorescence. IgG and IgM anticardiolipin antibodies (aCL) were detected using commercial ELISA. The prevalence of ANA and ANCA was similar in CAE patients and controls (33.3 vs. 43.3%, and 3.3 vs. 7.4%, respectively). There was no significant difference in IgG or IgM aCL reactivity between patients and controls. Both CAE patients and controls were negative for IgG AECA. The frequency of IgM AECA positivity was similar in CAE patients and controls. The prevalence of AECA of the IgA isotype was significantly higher in CAE patients (37.0 vs. 10%, P

OBJECTIVES: Analysis of conventional angiograms has suggested that specific anatomic parameters of particular segments of a coronary artery render them prone to vulnerable plaque development, plaque rupture, and consequent thrombosis. This study aimed at performing a three-dimensional analysis of recanalized left anterior descending (LAD) coronary arteries in patients who had suffered an anterior ST-elevation myocardial infarction (STEMI). METHODS: Coronary angiograms of 76 consecutive patients with an anterior STEMI and a recanalized LAD were reconstructed in the three-dimensional space, and compared with angiograms of 76 patients with stable coronary artery disease (SCAD) and significant LAD stenosis. RESULTS: In both groups the majority of lesions occurred between 20 and 40 mm (P=0.745), but the number of lesions beyond 60 mm from the ostium was significantly higher in SCAD compared with STEMI (P=0.045). Culprit lesions were statistically significantly longer in patients with STEMI compared with SCAD (18.3±7.5 vs. 12.7±6.2 mm, P

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 0.6 mSv versus 13.4 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a 'step-and-shoot' protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality. © 2009 Institute of Physics and Engineering in Medicine.

Following the development of the first automated methods in the 1980s, quantitative coronary angiography (QCA) has undergone substantial evolution from simplistic computer-assisted methods of visual interpretation of coronary angiograms to recently introduced three-dimensional reconstruction and quantitative analysis algorithms. The ability of QCA to provide objective dimensional assessment of coronary lesions is still useful and has led to its widespread application in both scientific research and clinical practice. Most of the systems available nowadays are based on vessel edge detection algorithms to designate the arterial lumen on conventional two-dimensional coronary angiograms. Three generations of these systems have been developed with improved accuracy and precision of obtained measurements. Techniques for reconstruction of the two-dimensional coronary angiogram in space have allowed the implementation of three-dimensional QCA. This new technology may solve many of the limitations inherent in two-dimensional QCA and provide stenosis assessment capabilities not available with two-dimensional imaging. © 2009 Elsevier Inc. All rights reserved.

Objective: This study aimed at comparing three-dimensional (3-D) reconstruction with two-dimensional coronary angiograms with respect to anatomical parameters that might affect plaque formation and rupture. Methods: Sixty patients with stable left anterior descending (LAD) lesions and 60 patients with an anteroseptal myocardial infarction and recanalized LAD were studied. Results: Conventional angiography significantly underestimated the distance of the stenosis from the ostium of the LAD, 29.4 ±14.5 versus 35.3±18.5 mm, P

Background: A detailed analysis of the anatomic relationships of the site of culprit lesions that have resulted in acute coronary syndromes (ACS) has not been reported. Methods: Coronary angiograms of consecutive patients who presented with ACS were analyzed according to multiple anatomic criteria. Results: In left anterior descending artery (LAD) (n = 85), 85% of culprit lesions were located in the first 40 mm from the ostium. The presence of angulation on the lesion increased the risk of an ACS 1.92 times (95% confidence interval [CI] 1.9-3.07), and the presence of bifurcation after the lesion increased the risk 1.65 times (95% CI 1.04-2.62). Angulated lesions located within the first 40 mm from the ostium and before a bifurcation presented an 11-fold increased risk for an ACS. In right coronary artery (RCA) (n = 58), the risk of plaque rupture was almost 2.5 times higher in lesions located between 10 and 50 mm from the ostium compared to those located in 90-130 mm (relative risk [RR] 2.38, 95% CI 1.25-4.56). In left circumflex (LCx) (n = 40), the risk of plaque rupture was almost 4.5 and 5 times higher in the first 20 mm, and between 20 and 40 mm from the ostium, respectively, compared to 60 and 80 mm (relative risk [RR] 4.58, 95% CI 1.01-20.68 for 0-20 mm, and RR 4.95, 95% CI 1.14-21.47 for 20-40 mm) after adjustment for the presence of curve on the lesion. The presence of lesion angulation increased the risk of plaque rupture almost three times (RR 3.22, 95% CI 1.49-6.93). Conclusion: Specific anatomic features of the coronary arteries predispose to development and/or subsequent rupture of vulnerable plaques. © 2008, the Authors.

Wall shear stress is a fluid dynamic quantity that is gradually emerging as a potentially important factor of coronary atherosclerosis. Methods, therefore, of estimation of shear stress in the arterial system are of clinical relevance. The purpose of this review is to define wall shear stress, review the various methods that have been used for its assessment in human circulation, and examine the methodological limitations and applicability of each method in clinical practice. © 2007 Bentham Science Publishers Ltd.

Percutaneous coronary interventions are associated with increased radiation exposure compared to most radiological examinations. This prospective study aimed at (1) measuring entrance doses for all in-room personnel, (2) performing an assessment of patient effective dose and intracoronary doses, (3) investigating the contribution of each projection to kerma-area product (KAP) and irradiation time, (4) comparing results with established DRL values in this clinical setting and (5) estimating the risk for fatal cancer to patients and operators. Measurements were performed during 40 consecutive procedures of coronary angiography (CA), half of which were followed by ad hoc coronary angioplasty (PTCA). KAP measurements were used for patients and thermoluminescent dosimetry for the in-room personnel. The mean KAP value per procedure for CA was 29 ± 9 Gy cm2. Thirty four per cent of KAP was due to fluoroscopy, whereas the remainder (66%) was due to digital cine. Accordingly, the mean KAP value per PTCA procedure was 75 ± 30 Gy cm2, and contribution of fluoroscopy is 57%. Effective dose per year was estimated to be 0.04-0.05 mSv y-1 for the primary operator, and 0.03-0.04 mSv y-1 for those assisting. Corresponding measurements for radiographer and nurse were below detectable level, implying minimal radiation hazards for them. Regarding radiation exposure, coronary intervention is considered a quite safe procedure for both patients and personnel in laboratories with modern equipment and experienced operators as long as standard safety precautions are considered. Exposure optimization though should be constantly sought through continuous review of procedures.