Initial results on in vivo human coronary MR angiography at 7 T.

Seven tesla (T) MR imaging is potentially promising for the morphologic evaluation of coronary arteries because of the increased signal-to-noise ratio compared to lower field strengths, in turn allowing improved spatial resolution, improved temporal resolution, or reduced scanning times. However, there are a large number of technical challenges, including the commercial 7 T systems not being equipped with homogeneous body radiofrequency coils, conservative specific absorption rate constraints, and magnified sample-induced amplitude of radiofrequency field inhomogeneity. In the present study, an initial attempt was made to address these challenges and to implement coronary MR angiography at 7 T. A single-element radiofrequency transmit and receive coil was designed and a 7 T specific imaging protocol was implemented, including significant changes in scout scanning, contrast generation, and navigator geometry compared to current protocols at 3 T. With this methodology, the first human coronary MR images were successfully obtained at 7 T, with both qualitative and quantitative findings being presented.

Vessel centerline tracking and boundary sgementation in coronary MRA with minimal manual interaction.

Magnetic resonance angiography (MRA) provides a noninvasive means to detect the presence, location and severity of atherosclerosis throughout the vascular system. In such studies, and especially those in the coronary arteries, the vessel luminal area is typically measured at multiple cross-sectional locations along the course of the artery. The advent of fast volumetric imaging techniques covering proximal to mid segments of coronary arteries necessitates automatic analysis tools requiring minimal manual interactions to robustly measure cross-sectional area along the three-dimensional track of the arteries in under-sampled and non-isotropic datasets. In this work, we present a modular approach based on level set methods to track the vessel centerline, segment the vessel boundaries, and measure transversal area using two user-selected endpoints in each coronary of interest. Arterial area and vessel length are measured using our method and compared to the standard Soap-Bubble reformatting and analysis tool in in-vivo non-contrast enhanced coronary MRA images.

Retroviral infection of neonatal Peyer's patch lymphocytes: the mouse mammary tumor virus model.

Mouse mammary tumor virus is known to infect newborn mice via mother's milk. A proposed key step for viral spread to the mammary gland is by the infection of lymphocytes. We show here that although in suckling mice retroviral proteins are found in all epithelial cells of the gut, viral DNA is exclusively detectable in the Peyer's patches. As early as 5 d after birth the infection leads to a superantigen response in the Peyer's patches but not in other lymphoid organs draining the intestine. Viral DNA can be detected before the superantigen response and becomes first evident in the Peyer's patches followed by mesenteric lymph nodes and finally all lymphoid organs.

Initial experience with hybrid surgery in congenital heart disease in a single center : P171

Introduction: A hybrid intervention is a joint procedure involving the interventional cardiologist and the cardiac surgeon. At our institution we have opted for this type of approach in congenital heart disease since 2005. We report here our initial experience. Cases: 1. A 3 year old boy with double aortic arch and multiple muscular ventricular septal defects (VSD),was readdressed for pulmonary band (PAB) removal and residual VSD closure after previous palliation. After surgical removal of the PAB, the surgeon provided a minimal transventricular access for placement of a 6mm Amplatzer® muscular VSD occluder by the cardiologist under transoesophageal guidance. The patient was extubated the same day and discharged after 5 days. 2. An 8 year old girl with Williams syndrome was followed for two large VSDs and severe peripheral pulmonary arteries (PA) stenosis. The membranous VSD was closed surgically, the muscular VSD during the same operation by direct placement of a 12 mm Amplatzer® muscular VSD occluder. During rewarming, balloon angioplasty of peripheral PA stenosis was achieved under fluoroscopy. Patient was extubated the following day and discharged after 8 days. 3. A 9 year old boy post tetralogy of Fallot repair had severe distal stenosis of the right ventricular to PA conduit.With patient on partial cardiopulmonary bypass, an incision was made on the conduit and a CP 8 Zig 16 stent placed on the stenosis. The child passed on full bypass and the definitive placement of the stent achieved. The child was extubated at the end of the intervention and discharged after 6 days. 4. A newborn presented at 2 days life with complex aortic arch anatomy: left aortic arch and right descending thoracic aorta perfused directly from a right arterial duct and left PA atresia. The arterial duct was stented with a Genesis XD stent dilated at 7mm. Two days later the cardiac surgeon made banded the right PA. The child was extubated after the operation and discharged a week later. Conclusion: Hybrid approach opens new ways of correction or palliation in congenital heart disease with encouraging results and less morbidity.

Diabetic neuropathy is a more important determinant of baroreflex sensitivity than carotid elasticity in type 2 diabetes.

The object of this study was to evaluate the contribution of carotid distensibilty on baroreflex sensitivity in patients with type 2 diabetes mellitus with at least 2 additional cardiovascular risk factors. Carotid distensibility was measured bilaterally at the common carotid artery in 79 consecutive diabetic patients and 60 matched subjects without diabetes. Spontaneous baroreflex sensitivity assessment was obtained using time and frequency methods. Baroreflex sensitivity was lower in diabetic subjects as compared with nondiabetic control subjects (5.25+/-2.80 ms/mm Hg versus 7.55+/-3.79 ms/mm Hg; P<0.01, respectively). Contrary to nondiabetic subjects, diabetic subjects showed no significant correlation between carotid distensibility and baroreflex sensitivity (r2=0.08, P=0.04 and r2=0.04, P=0.13, respectively). In diabetic subjects, baroreflex sensitivity was significantly lower in subjects with peripheral neuropathy than in those with preserved vibration sensation (4.1+/-0.5 versus 6.1+/-0.4 ms/mm Hg, respectively; P=0.005). Age in nondiabetic subjects, diabetes duration, systolic blood pressure, peripheral or sensitive neuropathy, and carotid distensibility were introduced in a stepwise multivariate analysis to identify the determinants of baroreflex sensitivity. In diabetic patients, neuropathy is a more sensitive determinant of baroreflex sensitivity than the reduced carotid distensibility (stepwise analysis; F ratio=5.1, P=0.028 versus F ratio=1.9, P=0.16, respectively). In diabetic subjects with 2 additional cardiovascular risk factors, spontaneous baroreflex sensitivity is not related to carotid distensibility. Diabetic subjects represent a particular population within the spectrum of cardiovascular risk situations because of the marked neuropathy associated with their metabolic disorder. Therefore, neuropathy is a more significant determinant of baroreflex sensitivity than carotid artery elasticity in patients with type 2 diabetes.

Telementoring during endovascular treatment of abdominal aortic aneurysms: a prospective study.

PURPOSE: To explore the use of telementoring for distant teaching and training in endovascular aortic aneurysm repair (EVAR). METHODS: According to a prospectively designed study protocol, 48 patients underwent EVAR: the first 12 patients (group A) were treated at a secondary care center by an experienced interventionist, who was training the local team; a further 12 patients (group B) were operated by the local team at their secondary center with telementoring by the experienced operator from an adjacent suite; and the last 24 patients (group C) were operated by the local team with remote telementoring support from the experienced interventionist at a tertiary care center. Telementoring was performed using 3 video sources; images were transmitted using 4 ISDN lines. EVAR was performed using intravascular ultrasound and simultaneous fluoroscopy to obtain road mapping of the abdominal aorta and its branches, as well as for identifying the origins of the renal arteries, assessing the aortic neck, and monitoring the attachment of the stent-graft proximally and distally. RESULTS: Average duration of telementoring was 2.1 hours during the first 12 patients (group B) and 1.2 hours for the remaining 24 patients (group C). There was no difference in procedural duration (127+/-59 minutes in group A, 120+/-4 minutes in group B, and 119+/-39 minutes in group C; p=0.94) or the mean time spent in the ICU (26+/-15 hours in group A, 22+/-2 hours in group B, and 22+/-11 hours for group C; p=0.95). The length of hospital stay (11+/-4 days in group A, 9+/-4 days in group B, and 7+/-1 days in group C; p=0.002) was significantly different only for group C versus A (p=0.002). Only 1 (8.3%) patient (in group A: EVAR performed by the experienced operator) required conversion to open surgery because of iliac artery rupture. This was the only conversion (and the only death) in the entire study group (1/12 in group A versus 0/36 in groups B + C, p=0.31). CONCLUSIONS: Telementoring for EVAR is feasible and shows promising results. It may serve as a model for development of similar projects for teaching other invasive procedures in cardiovascular medicine.

Extension of Murray's law using a non-Newtonian model of blood flow.

BACKGROUND: So far, none of the existing methods on Murray's law deal with the non-Newtonian behavior of blood flow although the non-Newtonian approach for blood flow modelling looks more accurate. MODELING: In the present paper, Murray's law which is applicable to an arterial bifurcation, is generalized to a non-Newtonian blood flow model (power-law model). When the vessel size reaches the capillary limitation, blood can be modeled using a non-Newtonian constitutive equation. It is assumed two different constraints in addition to the pumping power: the volume constraint or the surface constraint (related to the internal surface of the vessel). For a seek of generality, the relationships are given for an arbitrary number of daughter vessels. It is shown that for a cost function including the volume constraint, classical Murray's law remains valid (i.e. SigmaR(c) = cste with c = 3 is verified and is independent of n, the dimensionless index in the viscosity equation; R being the radius of the vessel). On the contrary, for a cost function including the surface constraint, different values of c may be calculated depending on the value of n. RESULTS: We find that c varies for blood from 2.42 to 3 depending on the constraint and the fluid properties. For the Newtonian model, the surface constraint leads to c = 2.5. The cost function (based on the surface constraint) can be related to entropy generation, by dividing it by the temperature. CONCLUSION: It is demonstrated that the entropy generated in all the daughter vessels is greater than the entropy generated in the parent vessel. Furthermore, it is shown that the difference of entropy generation between the parent and daughter vessels is smaller for a non-Newtonian fluid than for a Newtonian fluid.

Occlusion postcontusionnelle de l'artère et de la veine centrale de la rétine [Post-concussion occlusion of the central artery and vein of the retina]

BACKGROUND: Combined simultaneous occlusion of the central retinal artery and central retinal vein occurs very rarely and has been observed in patients with systemic disorders such as leukaemia. CASE REPORT: We report a case of a young man who suffered a combined retinal vascular occlusion with occlusion of the posterior ciliary arteries following blunt trauma to the face with massive haematoma of the lids. To our knowledge, this is the first time that such a sequence of events has been recorded.

Transcranial Doppler for predicting delayed cerebral ischemia after subarachnoid hemorrhage.

OBJECTIVE: Transcranial Doppler (TCD) is widely used to monitor the temporal course of vasospasm after subarachnoid hemorrhage (SAH), but its ability to predict clinical deterioration or infarction from delayed cerebral ischemia (DCI) remains controversial. We sought to determine the prognostic utility of serial TCD examination after SAH. METHODS: We analyzed 1877 TCD examinations in 441 aneurysmal SAH patients within 14 days of onset. The highest mean blood flow velocity (mBFV) value in any vessel before DCI onset was recorded. DCI was defined as clinical deterioration or computed tomographic evidence of infarction caused by vasospasm, with adjudication by consensus of the study team. Logistic regression was used to calculate adjusted odds ratios for DCI risk after controlling for other risk factors. RESULTS: DCI occurred in 21% of patients (n = 92). Multivariate predictors of DCI included modified Fisher computed tomographic score (P = 0.001), poor clinical grade (P = 0.04), and female sex (P = 0.008). After controlling for these variables, all TCD mBFV thresholds between 120 and 180 cm/s added a modest degree of incremental predictive value for DCI at nearly all time points, with maximal sensitivity by SAH day 8. However, the sensitivity of any mBFV more than 120 cm/s for subsequent DCI was only 63%, with a positive predictive value of 22% among patients with Hunt and Hess grades I to III and 36% in patients with Hunt and Hess grades IV and V. Positive predictive value was only slightly higher if mBFV exceeded 180 cm/s. CONCLUSION: Increased TCD flow velocities imply only a mild incremental risk of DCI after SAH, with maximal sensitivity by day 8. Nearly 40% of patients with DCI never attained an mBFV more than 120 cm/s during the course of monitoring. Given the poor overall sensitivity of TCD, improved methods for identifying patients at high risk for DCI after SAH are needed.

Ultrasound assessment of ocular vascular effects of repeated intravitreal injections of ranibizumab for wet age-related macular degeneration.

PURPOSE: Determine the effect of repeated intravitreal injections of ranibizumab (0.5 mg; 0.05 ml) on retrobulbar blood flow velocities (BFVs) using ultrasound imaging quantification in twenty patients with exudative age-related macular degeneration treated for 6 months. METHODS: Visual acuity (ETDRS), central macular thickness (OCT), peak-systolic, end-diastolic and mean-BFVs in central retinal (CRA), temporal posterior ciliary (TPCA) and ophthalmic (OA) arteries were measured before, 2 days, 3 weeks and 6 months after the first injection. Patients were examined monthly and received 1-5 additional injections depending on ophthalmologic examination results. RESULTS: Six months after the first injection, a significant increase in visual acuity 50.9 ± 25.9 versus 44.4 ± 21.7 (p < 0.01) and decrease in mean central macular thickness 267 ± 74 versus 377 ± 115 μm (p < 0.001) were observed compared to baseline. Although mean-BFVs decreased by 16%±3% in CRA and 20%±5% in TPCA (p < 0.001) 2 days after the first injection, no significant change was seen thereafter. Mean-BFVs in OA decreased by 19%±5% at week 3 (p < 0.001). However, the smallest number of injections (two injections) was associated with the longest time interval between the last injection and month 6 (20 weeks) and with the best return to baseline levels for mean-BFVs in CRA, suggesting that ranibizumab had reversible effects on native retinal vascular supply after its discontinuation. Moreover, a significant correlation between the number of injections and percentage of changes in mean-BFVs in CRA was observed at month 6 (R = 0.74, p < 0.001) unlike TPCA or OA. CONCLUSION: Ranibizumab could impair the native choroidal and retinal vascular networks, but its effect seems reversible after its discontinuation.

Risk factor impact on blood flow velocities and clinical outcomes of stented cervical and intracranial stenoses: preliminary observations.

OBJECTIVES: The role of angioplasty/stenting procedures, neurointerventionist experience, vascular risk factors, medical treatment and blood flow velocities were analysed to identify possible causes of intra-stent restenosis (ISR) following stenting of cervical and/or intracranial arteries, assuming progressive atherosclerosis to be the shared mechanism in both territories. Patients. 26 cerebrovascular patients subjected to stenting of severe (≥85%) symptomatic or asymptomatic carotid stenoses or moderate-to-severe (≥50%) intracranial or vertebral stenoses were included. METHODS: Clinical, radiological and ultrasonographic follow-up data were analysed retrospectively. RESULTS: Overall, stenting of the internal carotid artery (ICA) induced significant reductions in peak systolic velocities at 2 years (96±31cm/s vs. 358.2±24.9cm/s at baseline). The procedure-related ischemic complications rate was 7.4% (one hemispheric stroke and one TIA). The rate of ISR≤50% was 8% in the ICA at 2 years; was 50% in the common carotid artery (CCA) at 1 year, with concomitant distal ICA stenosis in 75% of CCA stenting, but all ISR were asymptomatic. Patients with ISR of the ICA were significantly younger (56.8±4.5 vs. 71.3±3.6 years, P=0.042) and had significantly more risk factors (5.5±0.9 vs. 3±0.3, P=0.012). No ISR≥70% was detected. CONCLUSIONS: ISR is relatively infrequent and, when present, it is mild and asymptomatic. Restenosis is more frequent in younger patients and those with several risk factors, and it may also be related to stenting of previous carotid endarterectomy.

"Soap-Bubble" visualization and quantitative analysis of 3D coronary magnetic resonance angiograms.

In order to compare coronary magnetic resonance angiography (MRA) data obtained with different scanning methodologies, adequate visualization and presentation of the coronary MRA data need to be ensured. Furthermore, an objective quantitative comparison between images acquired with different scanning methods is desirable. To address this need, a software tool ("Soap-Bubble") that facilitates visualization and quantitative comparison of 3D volume targeted coronary MRA data was developed. In the present implementation, the user interactively specifies a curved subvolume (enclosed in the 3D coronary MRA data set) that closely encompasses the coronary arterial segments. With a 3D Delaunay triangulation and a parallel projection, this enables the simultaneous display of multiple coronary segments in one 2D representation. For objective quantitative analysis, frequently explored quantitative parameters such as signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); and vessel length, sharpness, and diameter can be assessed. The present tool supports visualization and objective, quantitative comparisons of coronary MRA data obtained with different scanning methods. The first results obtained in healthy adults and in patients with coronary artery disease are presented.

Efficiency of coronary artery disease screening guidelines in asymptomatic and atypical chest pain type 2 diabetic patients

RESUME Objectifs. Évaluer la prévalence de maladie coronarienne chez les patients diabétiques de type 2 asymptomatiques ou avec angor atypique selon les recommandations américaines de l'American Diabetes Association et de l'American College of Cardiology. Méthodes. Cent cinquante-quatre patients diabétiques de type 2 asymptomatiques ou avec angor atypique et présentant au minimum 2 facteurs de risque cardio-vasculaires additionnels ont été dépistés par échocardiographie de stress (71%, n=109), scintigraphie myocardique de perfusion (26%, n=40) ou l'association des 2 examens (3%, n=5). Résultats. L'échocardiographie de stress s'est révélée positive chez 16 patients (14%) et 14 ont eu une coronarographie révélant des sténoses significatives chez 12 (86%). La scintigraphie myocardique de perfusion était positive chez 16 patients (36%). Huit patients ont eu une coronarographie et 4 (50%) présentaient des sténoses significatives. Au total, 31 patients (20%) ont montré des signes d'ischémie lors de l'examen non-invasif et 15 (10%) ont présenté des sténoses significatives à la coronarographie. Les facteurs prédictifs indépendants de la maladie coronarienne étaient le tabagisme (OR 6.5, p=0.05), la microalbuminurie (OR 3.9, p=0.03), ainsi que les souffles fémoraux (OR 17.1, p=0.008). Conclusions. En suivant les recommandations américaines, un patient sur cinq présentait une ischémie lors des examens non-invasifs, tandis que 1 sur 10 avait des sténoses significatives à la coronarographie. L'analyse multivariée suggère que des marqueurs des complications micro- et macro-vasculaires en combinaison avec des facteurs de risque cardio-vasculaire classiques pourraient améliorer le pouvoir diagnostic de ces recommandations. SUMMARY Aims. We evaluated the prevalence of coronary artery disease in asymptomatic and atypical chest pain type 2 diabetic patients according to the American Diabetes Association and American College of Cardiology guidelines. Methods. Asymptomatic or atypical chest pain type 2 diabetic patients (n=154), with at least two additional cardiovascular risk factors, were screened for coronary artery disease using stress echocardiography (71%, n=109), myocardial perfusion imaging (26%, n=40) or both (3%, n=5). Results. Stress echocardiography was positive in 16 patients (14%) and 14 had a coronary angiography, revealing significant stenoses in 12 (86%). Myocardial perfusion imaging was positive in 16 patients (36%). Eight patients underwent angiography and 4 (50%) presented significant stenoses. Overall, 31 patients (20%) demonstrated signs of ischemia on non-invasive tests and 15 (10%) presented significant stenoses on coronary angiography. Independent predictors of coronary artery disease were smoking (OR 6.5, p=0.05), microalbuminuria (OR 3.9, p=0.03) and femoral murmur (OR 17.1, p=0.008). Conclusions. Following the guidelines, one in five diabetic patient presented ischemia on noninvasive tests, while one in ten presented significant coronary stenoses. Multivariate analysis suggests that adding markers of micro- and macro-vascular complications to classical cardiovascular risk factors may enhance the diagnostic efficiency of the guidelines.

Percutaneous coronary interventions prior to coronary artery bypass surgery.

BACKGROUND AND AIM OF THE STUDY: Percutaneous coronary interventions (PCI) are frequently performed before coronary artery bypass graft (CABG) surgery. This study sought to evaluate postoperative outcomes, and incidence of recurrent target ischemia in vessels with prior PCI in patients who had PCI prior to CABG compared to only CABG patients. METHODS: A review included CABG patients operated from 2000 to 2012. PCI prior to CABG patients were compared with patients having had CABG on native coronary arteries. Demographic and risk factors, including hospital morbidity, mortality, and recurrent target vessel ischemia at follow-up (FU), were compared. Major end-points were statistical differences of postoperative morbidity and reintervention rates due to symptomatic graft failure or target vessel ischemia during FU. RESULTS: Twenty-four percent of 1669 isolated CABG patients had PCI prior to CABG, with an increasing percentage during recent years. Demographics, risk factors, comorbidities and mortality rates were similar. Incidence of postoperative hemorrhage (OR 1.9; 95% CI 1.1-3.2; p = 0.02), perioperative myocardial infarction rate (p = 0.02), neurological deficits (OR 3.5; 95% CI 1.2-9.7; p = 0.02) and re-intervention rate for symptomatic graft or target vessel occlusion were higher in pretreated patients (OR 1.8; 95% CI 1.1-3.0; p = 0.01). CONCLUSIONS: PCI prior to CABG increases the risk for postoperative morbidity. Increased postoperative hemorrhage could be attributed to ongoing double anti-platelet therapy. doi: 10.1111/jocs.12514 (J Card Surg 2015;30:313-318).

The year in cardiology 2014: peripheral circulation.

In 2014, the debate on the indication of revascularization in case of asymptomatic carotid disease continued, while another one regarding the use of surgery vs. stenting addressed some new issues regarding the long-term cardiac risk of these patients. Renal arteries interventions trials were disappointing, as neither renal denervation nor renal artery stenting was found associated with better blood pressure management or outcome. In contrast, in lower-extremities artery disease, the endovascular techniques represent in 2014 major alternatives to surgery, even in distal arteries, with new insights regarding the interest of drug-eluting balloons. Regarding the aorta, the ESC published its first guidelines document on the entire vessel, emphasizing on the role of every cardiologist for screening abdominal aorta aneurysm during echocardiography. Among vascular wall biomarkers, the aorta stiffness is of increasing interest with new data and meta-analysis confirming its ability to stratify risk, whereas carotid intima-media thickness showed poor performances in terms of reclassifying patients into risk categories beyond risk scores. Regarding the veins, new data suggest the interest of D-dimers and residual venous thrombosis to help the decision of anti-coagulation prolongation or discontinuation after the initial period of treatment for deep vein thrombosis.