Scar quantification by cardiovascular magnetic resonance as an independent predictor of long-term survival in patients with ischemic heart failure treated by coronary artery bypass graft surgery.

BACKGROUND: Scar burden by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is associated with functional recovery after coronary artery bypass surgery (CABG). There is limited data on long-term mortality after CABG based on left ventricular (LV) scar burden. METHODS: Patients who underwent LGE CMR between January 2003 and February 2010 within 1 month prior to CABG were included. A standard 16 segment model was used for scar quantification. A score of 1 for no scar, 2 for ≤ 50 % and 3 for > 50 % transmurality was assigned for each segment. LV scar score (LVSS) defined as the sum of segment scores divided by 16. All-cause mortality was ascertained by social security death index. RESULTS: One hundred ninety-six patients met the inclusion criteria. 185 CMR studies were available. History of prior MI was present in 64 % and prior CABG in 5.4 % of patients. Scar was present in 72 % of patients and median LVEF was 38 %. Over a median follow up of 8.3 years, there were 64 deaths (34.6 %). There was no statistically significant difference in mortality between Scar and No-scar groups (37 % versus 29 %). In the group with scar, a lower scar burden (defined either < 4 segments with scar or based on LVSS) was independently associated with increased survival. CONCLUSION: In patients undergoing surgical revascularization, scar burden is negatively associated with survival in patients with scar. However, there is no difference in survival based on presence or absence of scar alone. CMR prior to CABG adds additional prognostic information.

Pulmonary vein morphology by free-breathing whole heart magnetic resonance imaging at 3 Tesla versus breathhold multi-detector computed tomography.

PURPOSE: To compare pulmonary vein and left atrial anatomy using three-dimensional free-breathing whole-heart magnetic resonance imaging (MR) at 3 Tesla (T) and multi-detector computed tomography (MDCT). MATERIALS AND METHODS: Thirty-three subjects (19 male, age 49 ± 12 years) underwent free-breathing 3T MR and contrast-enhanced MDCT during inspiratory breath hold. Pulmonary vein parameters (ostial areas, diameters, angles) were measured. RESULTS: All pulmonary veins and anomalies were identified by 3T MR and by MDCT. The right-sided pulmonary veins were directed more posteriorly, the right superior pulmonary vein more inferiorly, and the right inferior pulmonary vein more superiorly by 3T MR when compared with MDCT. The cross-sectional area, perimeters and minimum diameters of right-sided pulmonary vein ostia were significantly larger by MR, as were the maximum diameters of right and left inferior pulmonary veins. There were no significant differences between techniques in distance to first pulmonary vein branch. CONCLUSION: Pulmonary vein measurements demonstrated significant differences in angulations and dimensions when 3T MR is compared with MDCT. These differences likely represent hemodynamic and respiratory variation during free-breathing with MR versus breath-holding with MDCT. MR imaging at 3T during free-breathing offers an alternate method to define pulmonary vein and left atrial anatomy without exposure to radiation.

Coronary computed tomography versus coronary angiography for preoperative coronary assessment before valve surgery.

BACKGROUND: Conventional coronary angiography (CAG) is currently the gold standard technique for the assessment of coronary arteries prior to cardiac valve surgery. Although CAG is a relatively safe procedure, however, it is still an invasive procedure, and it has potential hazards and complications. Coronary computed tomography angiography (CCTA) is a non-invasive technique that has emerged robustly as an excellent and attractive tool for delineating coronary anatomy. Therefore, we sought to evaluate the accuracy of CCTA when compared with the gold standard CAG in the evaluation of coronary arteries before valve surgery. We screened 111 consecutive patients with VHD undergoing a routine cardiac catheterization for preoperative evaluation of CAD. Fifty patients were eligible and underwent both CAG and CCTA. Significant coronary stenosis was defined as a luminal diameter decrease of ≥ 50%. Additionally, ectasia, calcifications, and congenital coronary anomalies were analyzed. Also, we compared both techniques regarding radiation dose, contrast volume, and complications. Non-evaluable segments were excluded from all levels of analysis. Sixty-one patients were excluded from the study due to various reasons. RESULTS: Among the 50 patients of the study population, 27 (54%) were males. The prevalence of significant CAD in the study population was 19.6% according to the patient-based analysis, and CAG could have been avoided in 80.4% of patients with a true-negative CCTA result. Diagnostic accuracy of CCTA for detection of significant stenosis was evaluated regarding sensitivity and specificity, positive predictive value, negative predictive value, and overall accuracy of CCTA, which was 87.5%, 99.6%,87.5%, 99.6%, and 99.2%, respectively, for segmental-based analysis; 86%, 100%, 100%, 99%, and 99%, respectively, for vessel-based analysis; and 77.8%,100%,100%, 94.9%, and 95.7%, respectively, for patient-based analysis. Fewer rates of complications were encountered with CCTA. Additional information obtained like calcifications and congenital anomalies was diagnosed better with CCTA than CAG. CONCLUSION: Owing mainly to its high negative predictive value, a well-performed CCTA exam is an excellent method to rule out coronary artery disease, specially in patients who are not at high risk of atherosclerosis.

Total versus staged versus functional revascularization in NSTEACS patients with multivessel disease.

BACKGROUND: The optimal strategy for revascularization in patients with NSTEACS who had multivessel coronary artery disease. A lack of evidence exists about the role of complete coronary revascularization by PCI in patients with non-ST segment elevation acute coronary syndrome (NSTEACS). Till now, ACC/AHA and ESC guidelines are not clear regarding the optimal strategy for revascularization in NSTEACS patients with multivessel coronary artery disease. In this setting, identification of the culprit lesion by angiography only could be challenging. The objective is to compare the hospital and short-term (6 months) outcomes of 3 different coronary revascularization strategies in NSTEACS patients with and multivessel coronary artery disease. RESULTS: Our study was a prospective study that included 90 patients who presented with acute chest pain and were diagnosed with NSTEACS. The patients were divided into 3 groups according to the plan of management: total revascularization group (total group), staged revascularization group (staged group), and functional revascularization group using FFR (FFR group). We studied the effect of demographic data, risk factors, and angiographic and procedural criteria on hospital and short-term outcomes. No significant statistical difference was seen among the three groups regarding the hospital outcome (in-stent thrombosis, unstable angina, and renal impairment). Also, the short-term (after 6 months) outcome regarding myocardial infarction, hospitalization, stroke, and cardiac death did not differ significantly between the three groups. CONCLUSIONS: Considering NSTEACS patients with multivessel disease, different coronary revascularization strategies (total, staged, or FFR) are comparable regarding immediate and short-term (6 months) clinical follow-up. FFR can change the preplanned management, and less number of stents per patient is needed when FFR is utilized.

Characterization of the interatrial septum by high-field cardiac MRI: a comparison with multi-slice computed tomography.

BACKGROUND: Assessment of the interatrial septum (IAS) has become an attractive area of interest for a variety of important interventional procedures. Newer imaging modalities like multi-slice computed tomography (MSCT) and cardiac MRI (CMR) can provide higher resolution and wider field of view than echocardiography. Moreover, high-field (3-Tesla) CMR can even enhance spatial and temporal resolution. The characteristics of the interatrial septum were retrospectively studied in 371 consecutive subjects (201 men, 31-73 years old) in whom MSCT was performed primarily for non-invasive evaluation of the coronary arteries. All subjects underwent both MSCT and MRI scans within 0-30 day's interval. A 3D volume covering the whole heart was acquired across the heart with and without contrast enhancement. Also, patients underwent cardiac MSCT examinations using 64-row MSCT scanners. RESULTS: The mean scan time of MSCT was 10.4 ± 2.8 s and 9.7 ± 2.9 min for CMR. The mean length of IAS by CMR and CT was 39.65 ± 4.6 mm and 39.28 ± 4.7 mm, respectively. The mean maximal thickness of IAS by CMR and CT was 3.1 ± 0.97 mm and 3.15 ± 0.95 mm, respectively. The mean thickness of fossa ovalis by CMR and CT was 1.04 ± 0.36 mm and 1.04 ± 0.44 mm, respectively. The mean length of fossa ovalis by CMR and CT was 12.8 ± 3.7 mm and 12.8 ± 3.5 mm, respectively. Finally, the mean angle of IAS by CMR and CT was identical (155 ± 9.2°). Measurements of various morphological features of IAS showed no statistically significant difference between CMR and CT, with an excellent correlation and close relationship regarding IAS length, maximal IAS thickness, fossa ovalis thickness, fossa ovalis length, and IAS angle (r = 0.98, 0.98, 0.95, 0.96, and 0.92, respectively). CONCLUSION: Whole-heart 3D acquisition at 3-T MRI using a free-breathing technique provides a valuable non-invasive imaging tool for excellent assessment of the interatrial septum-as compared to MSCT-that may have significant clinical implication for diagnostic purposes and therapeutic interventional procedures, as it may facilitate planning, improve outcome, and shorten its duration.

Coronary abnormalities in hyper-IgE recurrent infection syndrome: depiction at coronary MDCT angiography.

OBJECTIVE: Hyper-IgE recurrent infection syndrome (HIES or Job's syndrome) is a rare disorder affecting the immune system and connective tissues. The purpose of this study is to describe the coronary abnormalities in genetically confirmed HIES patients as depicted by coronary MDCT angiography (MDCTA). CONCLUSION: Coronary MDCTA has provided an opportunity for noninvasive evaluation of the coronary arteries in patients with HIES. These coronary abnormalities vary from tortuosity to ectatic dilation and focal aneurysms of the coronary arteries. Such an evaluation has potential value in identifying new aspects of this disease and thereby providing better understanding of the pathophysiology of the disorder.

Real-time MR imaging-guided laser atrial septal puncture in swine.

PURPOSE: The authors performed this study to report their initial preclinical experience with real-time magnetic resonance (MR) imaging-guided atrial septal puncture by using a MR imaging-conspicuous blunt laser catheter that perforates only when energized. MATERIALS AND METHODS: The authors customized a 0.9-mm clinical excimer laser catheter with a receiver coil to impart MR imaging visibility at 1.5 T. Seven swine underwent laser transseptal puncture under real-time MR imaging. MR imaging signal-to-noise ratio profiles of the device were obtained in vitro. Tissue traversal force was tested with a calibrated meter. Position was corroborated with pressure measurements, oximetry, angiography, and necropsy. Intentional non-target perforation simulated serious complication. RESULTS: Embedded MR imaging antennae accurately reflected the position of the laser catheter tip and profile in vitro and in vivo. Despite having an increased profile from the microcoil, the 0.9-mm laser catheter traversed in vitro targets with similar force (0.22 N +/- 0.03) compared with the unmodified laser. Laser puncture of the atrial septum was successful and accurate in all animals. The laser was activated an average of 3.8 seconds +/- 0.4 before traversal. There were no sequelae after 6 hours of observation. Necropsy revealed 0.9-mm holes in the fossa ovalis in all animals. Intentional perforation of the aorta and atrial free wall was evident immediately. CONCLUSIONS: MR imaging-guided laser puncture of the interatrial septum is feasible in swine and offers controlled delivery of perforation energy by using an otherwise blunt catheter. Instantaneous soft tissue imaging provides immediate feedback on safety.

Cardiac magnetic resonance at high field: promises and problems.

Cardiac magnetic resonance imaging (CMRI) at high magnetic field (3 Tesla) is rapidly evolving with many promising results. However, the challenges of field inhomogeneities and specific absorption rate limitations need to be addressed before reaping the benefits of high magnetic field for CMRI. This review focuses on the methods to overcome some of these challenges and the current and potential applications of this technology.

TGF-ß signaling mediates endothelial-to-mesenchymal transition (EndMT) during vein graft remodeling.

Veins grafted into an arterial environment undergo a complex vascular remodeling process. Pathologic vascular remodeling often results in stenosed or occluded conduit grafts. Understanding this complex process is important for improving the outcome of patients with coronary and peripheral artery disease undergoing surgical revascularization. Using in vivo murine cell lineage-tracing models, we show that endothelial-derived cells contribute to neointimal formation through endothelial-to-mesenchymal transition (EndMT), which is dependent on early activation of the Smad2/3-Slug signaling pathway. Antagonism of transforming growth factor-ß (TGF-ß) signaling by TGF-ß neutralizing antibody, short hairpin RNA-mediated Smad3 or Smad2 knockdown, Smad3 haploinsufficiency, or endothelial cell-specific Smad2 deletion resulted in decreased EndMT and less neointimal formation compared to controls. Histological examination of postmortem human vein graft tissue corroborated the changes observed in our mouse vein graft model, suggesting that EndMT is operative during human vein graft remodeling. These data establish that EndMT is an important mechanism underlying neointimal formation in interpositional vein grafts, and identifies the TGF-ß-Smad2/3-Slug signaling pathway as a potential therapeutic target to prevent clinical vein graft stenosis.

Necrotic core thickness and positive arterial remodeling index: emergent biomechanical factors for evaluating the risk of plaque rupture.

Fibrous cap thickness is often considered as diagnostic of the degree of plaque instability. Necrotic core area (Core(area)) and the arterial remodeling index (Remod(index)), on the other hand, are difficult to use as clinical morphological indexes: literature data show a wide dispersion of Core(area) thresholds above which plaque becomes unstable. Although histopathology shows a strong correlation between Core(area) and Remod(index), it remains unclear how these interact and affect peak cap stress (Cap(stress)), a known predictor of rupture. The aim of this study was to investigate the change in plaque vulnerability as a function of necrotic core size and plaque morphology. Cap(stress) value was calculated on 5,500 idealized atherosclerotic vessel models that had the original feature of mimicking the positive arterial remodeling process described by Glagov. Twenty-four nonruptured plaques acquired by intravascular ultrasound on patients were used to test the performance of the associated idealized morphological models. Taking advantage of the extensive simulations, we investigated the effects of anatomical plaque features on Cap(stress). It was found that: 1) at the early stages of positive remodeling, lesions were more prone to rupture, which could explain the progression and growth of clinically silent plaques and 2) in addition to cap thickness, necrotic core thickness, rather than area, was critical in determining plaque stability. This study demonstrates that plaque instability is to be viewed not as a consequence of fibrous cap thickness alone but rather as a combination of cap thickness, necrotic core thickness, and the arterial remodeling index.

Blunt atrial transseptal puncture using excimer laser in swine.

OBJECTIVES: We describe a new approach that may enhance safety of atrial transseptal puncture using a commercially available laser catheter that is capable of perforation only when energized. We test this approach in swine. BACKGROUND: Despite wide application, conventional needle transseptal puncture continues to risk inadvertent nontarget perforation and its consequences. METHODS: We used a commercial excimer laser catheter (0.9-mm Clirpath, Spectranetics). Perforation force was compared in vitro with a conventional Brockenbrough needle. Eight swine underwent laser transseptal puncture under X-ray fluoroscopy steered using a variety of delivery catheters. RESULTS: The 0.9-mm laser catheter traversed in vitro targets with reduced force compared with a Brockenbrough needle. In vitro, the laser catheter created holes that were 25-30% larger than the Brockenbrough needle. Laser puncture of the atrial septum was successful and accurate in all animals, evidenced by oximetry, pressure, angiography, and necropsy. The laser catheter was steered effectively using a modified Mullins introducer sheath and using two different deflectable guiding catheters. The mean procedure time was 15 +/- 6 min, with an average 3.0 +/- 0.8 sec of laser activation. There were no adverse sequelae after prolonged observation. Necropsy revealed discrete 0.9-mm holes in all septae. CONCLUSION: Laser puncture of the interatrial septum is feasible and safe in swine, using a blunt laser catheter that perforates tissues in a controlled fashion.