Automatic selection of initial points for exploratory vessel tracing in fluoroscopic images

Automatic extraction of vessel centerlines has been an essential process in most of the image guided diagnosis and therapy applications. Among a considerable number of methods, direct exploratory tracing method is known to be an efficient solution for reliable extraction of vessel features from two-dimensional fluoroscopic images. The first step of most automatic exploratory tracing algorithms is collecting a number of candidate initial seed points and their initial tracing directions. To detect reliable initial points, a validation step is required to filter out the false candidates and avoid unnecessary tracing. Staring from reliable initial points, the algorithm efficiently extracts the centerline points along the initial direction until certain pre-defined criteria are satisfied. However, most of these algorithms suffer from incomplete results due to inappropriate selection of the initial seed points. The conventional seed point selection algorithms either rely merely on signal-to-noise ratio analysis, which results in a large number of false traces, or impose a set of strict geometrical validation rules that lead to more false negatives and require more computation time. This paper presents a new method for efficient selection of initial points for exploratory tracing algorithms. The proposed method improves the performance upon existing methods by employing a combination of geometrical and intensity-based approaches

XANAP: A real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation in Asia.

Background: ROCKET AF and its East Asian subanalysis demonstrated that rivaroxaban was non-inferior to warfarin for stroke/systemic embolism (SE) prevention in patients with non-valvular atrial fibrillation (NVAF), with a favorable benefit-risk profile. XANAP investigated the safety and effectiveness of rivaroxaban in routine care in Asia-Pacific. Methods: XANAP was a prospective, real-world, observational study in patients with NVAF newly starting rivaroxaban. Patients were followed at ~3-month intervals for 1 year, or for ≥30 days after permanent discontinuation. Primary outcomes were major bleeding events, adverse events (AEs), serious AEs and all-cause mortality; secondary outcomes included stroke/SE. Major outcomes were adjudicated centrally. Results: XANAP enrolled 2273 patients from 10 countries: mean age was 70.5 years and 58.1% were male. 49.8% of patients received rivaroxaban 20 mg once daily (od), 43.8% 15 mg od and 5.9% 10 mg od. Mean treatment duration was 296 days, and 72.8% of patients had received prior anticoagulation therapy. Co-morbidities included heart failure (20.1%), hypertension (73.6%), diabetes mellitus (26.6%), prior stroke/non-central nervous system SE/transient ischemic attack (32.8%) and myocardial infarction (3.8%). Mean CHADS2, CHA2DS2-VASc and HAS-BLED scores were 2.3, 3.7 and 2.1, respectively. The rates (events/100 patient-years [95% confidence interval]) of treatment-emergent major bleeding, stroke and all-cause mortality were 1.5 (1.0-2.1), 1.7 (1.2-2.5) and 2.0 (1.4-2.7), respectively. Persistence was 66.2% at the study end. Conclusions: The real-world XANAP study demonstrated low rates of stroke and bleeding in rivaroxaban-treated patients with NVAF from Asia-Pacific. The results were consistent with the real-world XANTUS study and ROCKET AF

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

Prediction of Blood Flow Velocity and Leaflet Deformation Via 2D Mitral Valve Model

In the mitral valve, regional variations in structure and material properties combine to affect the biomechanics of the entire valve. Previous study, we know that mitral valve leaflet tissue is highly extensible. A two-dimensional model of the mitral valve was generated using an Arbitrary Lagrangian-Eulerian (ALE) mesh. A simple approximation of the heart geometry was used and the valve dimensions were based on measurements made. Valve open and closure was simulated using contact equations. So, the objective of this study was to investigate and predict flow and leaflet phenomena via simple 2D mitral valve model based on critical parameter of blood. Two stages of mitral valves analysis systolic and diastolic stages were investigated. The results show linear correlation between rigidity of the mitral valves leaflet and volume of backflow. Also the simulation predicted mitral valve leaflet displacement during closure agreed with our previous data analysis results and the results for blood flow velocity during systole condition through the mitral valve outlet as reported in the medical literature. In conclusions, these computational techniques are very useful in the study of both degenerative valve disease and failure of prostheses and will be continue developed to investigate heart valve failure and subsequent with surgical repair

Coronary Artery Center-Line Extraction Using Second Order Local Features

Of interest is the accurate and robust delineation of vessel center-lines for complete arterial tree structure in coronary angiograms which is an imperative step towards 3D reconstruction of coronary tree and feature-based registration of multiple view angiograms. Most existing center-line tracking methods encounter limitations in coping with abrupt variations in local artery direction and sudden changes of lumen diameter that occur in the vicinity of arterial lesions. This paper presents an improved center-line tracing algorithm for automatic extraction of coronary arterial tree based on robust local features. The algorithm employs an improved scanning schema based on eigenvalues of Hessian matrix for reliable identification of true vessel points as well as an adaptive look-ahead distance schema for calculating the magnitude of scanning profile. In addition to a huge variety of clinical examples, a well-established vessel simulation tool was used to create several synthetic angiograms for objective comparison and performance evaluation. The experimental results on the accuracy and robustness of the proposed algorithm and its counterparts under difficult situations such as poor image quality and complicated vessel geometry are presented

Institutional hypertension control in rural Malaysia: A single center study

Objectives: Hypertension is one of the most important risk factors for Cardiovascular Disease in Malaysia. Population-based hypertension control is extremely poor at only 6% based on the 1996 National Health and Morbidity Survey. It is important to gauge the level of hypertension control in institutional follow-up as it has important ramifications on the delivery of service amongst healthcare professionals in Malaysia. Methods: Three hundred and thirty one consecutive patients presenting with hypertension to the Medical Outpatients clinic of Hospital Tengku Ampuan Afzan, Kuantan, Malaysia were enrolled into a prospective observational study. Blood pressure readings were taken with manual sphygmomanometers. A review of the medications and co-morbidities was then undertaken. Results: The majority of patients were male 64.65%, with a mean age of 60.1±11.0 years. The mean systolic blood pressure (SBP) was 139.3±21.0 mmHg and the diastolic blood pressure (DBP) was 81.6±10.4 mmHg. 64.9% of patients had blood pressures (BP) within the 140/90 mmHg target. The mean blood pressure in this group was 127.1±11.5/77.8±7.7 mmHg. The majority of patients were on either 2 (46.5%) or 3 (25.9%) anti-hypertensives. Females had a significantly higher SBP 144.0±22.5 vs 136.8±19.7 mmHg (p=0.004, Independent t test). SBP was also found to be mildly correlated with gender (r = 0.16, p = 0.003), age (r = 0.11, p = 0.04) and hyperlipidaemia (r = 0.10, p = 0.05). Conclusion: The level of hypertension control is certainly equivalent if not better than western centers. It proves that the level hypertension control in tertiary institutions is far superior to that of population-based centers. This could be attributed to the availability of both a highly trained staff, greater surveillance and better medications

Cost-effectiveness of anti-hypertensive medications in a regional hospital in rural Malaysia

Objectives: Hypertension is one of the most important risk factors for Cardiovascular Disease in Malaysia. Population-based hypertension control is extremely poor at only 6% based on the 1996 National Health and Morbidity Survey. One of the possible reasons include the availability and cost of antihypertensive medications. Methods: A retrospective review of the annual cost (2006) of anti-hypertensive medications was undertaken at the Department of Pharmacy, Hospital Tengku Ampuan Afzan, a 600-bed major regional hospital on the east-coast of Malaysia. The total number of prescriptions given out and the total cost per drug is then factored to give the annual cost per drug per person in a percentage of the total annual expenditure. Results: The majority of patients were on either 2 (46.5%) or 3 (25.9%) anti-hypertensives. The most frequently prescribed medications were ACE-Inhibitors (33.45%), Calciumchannel blockers (29.63%), diuretics (16.67%), Beta blockers (13.64%) and Alpha blockers (2.69%). In terms of cost however, the Calcium-channel blockers constituted the greatest percentage of the annual anti-hypertensive budget (63.67%) compared to ACE-Inhibitors at just 20.04% of the annual expenditure. The most ‘cost-effective’ group of drugs are the diuretics making up 16.67% of the total annual prescriptions but only constituting 1.23% of the annual cost. Conclusion: The Calcium-channel blockers are the most ‘cost-ineffective’ medications available at our regional Hospital making up less than one third of the total annual prescriptions but making up nearly two-thirds of the annual anti-hypertensive budget. The most ‘cost-effective’ medications were diuretics, Beta-blockers and ACE-inhibitors in order of ‘cost-effectiveness’