Circumflex Artery Territory Research Articles

Exposure technique for the circumflex artery territory in robotic totally endoscopic coronary artery bypass grafting.

Exposure technique for the circumflex artery territory in robotic totally endoscopic coronary artery bypass grafting.

Abstract 3118: An Unusual Case Of Severe Multivessel Atherosclerotic Coronary Artery Disease In A Very Young Patient

Introduction: Premature coronary artery disease (CAD) is defined as CAD prior to the age of 55 for men and 65 for women, while CAD in young is defined as age <45 years. In the last decade, incidence of global premature CAD has increased by 25 %. Case presentation: A 20-year-old female with medical history of dyslipidemia, hypertension, type 1 diabetes mellitus and family history of premature coronary artery disease presented to the emergency room with chief complaint of chest pain and shortness of breath. EKG revealed sinus tachycardia and poor R-wave progression on anterior precordial leads. Serum troponin trend was unremarkable. Echocardiogram revealed severely reduced left ventricular (LV) ejection fraction of 20-25% with global LV hypokinesis, trace mitral and tricuspid regurgitation. Given new onset cardiomyopathy and family history of premature CAD, CT heart with coronary calcium scoring was performed which was concerning for severe LAD disease. Surprisingly, coronary angiogram revealed severe atherosclerotic disease in LAD, left circumflex and right coronary artery territories. Patient was started on guideline directed medical therapy for cardiomyopathy and has been referred to tertiary center for surgical revascularization. Discussion: To our best knowledge only one case has been reported before in the literature when a 21-year-old male patient had multivessel CAD requiring surgical revascularization. However, we report a case, which will be the youngest ever to have severe multivessel CAD needing surgical revascularization in the future. Cole et al, in a study of 800 young patients with CAD at long term follow up of 15 years, showed an overall mortality rate of 30 %, with 83% mortality rate in patients with EF< 30%, thus carrying a poor long-term prognosis.(2) Hence, an early initiation of treatment, including both medical therapy and revascularization should strongly be considered in these young patient population. Conclusion: With the increasing prevalence of premature CAD and associated risk factors, age alone should not be taken as a reliable indicator for risk stratifying patients. Emphasizing awareness among young adults with high risk of CAD that primary prevention and early lifestyle modification are of paramount importance.

Selecting conduits for coronary artery bypass grafting: caution regarding the right internal mammary artery

This narrative review summarizes the angiographic and clinical outcome results of the most common coronary artery bypass grafting (CABG) conduits. The left internal mammary artery is the preferred first conduit to bypass the left anterior descending artery due to superior long-term survival and graft patency. Recent studies suggest the radial artery may be the preferred second conduit for the circumflex or right coronary artery territories, challenging the belief that the right internal mammary artery is the best choice. Despite their historical high failure rates, saphenous vein grafts continue to be widely used as secondary conduits. Several recent studies report suboptimal rates of right internal mammary artery graft failure, with clinical outcomes comparable to or worse than saphenous veins. The suboptimal rates of RIMA graft failure may be attributed to several factors such as improvements in vein graft failure rates, the use of in situ and non-left anterior descending artery grafting configurations, and skeletonized harvesting techniques. While observational studies favor multiple over single arterial grafting, randomized studies are needed for confirmation. The ongoing Randomized comparison of the clinical Outcome of single vs. Multiple Arterial grafts (ROMA) trial aims to determine if multiple arterial grafting reduces major adverse cardiovascular events and mortality and how secondary conduit selection influences these outcomes. Greater adoption of arterial grafting strategies is likely to come from high-quality evidence of benefit and safety from ongoing and future large pragmatic trials.

Potential Role of Somatostatin Receptor Scintigraphy for In Vivo Imaging of Vulnerable Atherosclerotic Plaques and Its Association with Myocardial Perfusion Imaging Finding: A Preliminary Study.

This study was conducted to detect atherosclerotic plaques with somatostatin receptor scintigraphy (SRS) using Tc-99m-octreotide that binds to somatostatin receptor-2. Of the 783 patients referred for myocardial perfusion imaging (MPI), 52 underwent additional chest single-photon emission computed tomography (SPECT) with Tc-99m-octreotide and participated in this study. In addition, 43 patients who underwent Tc-99m-octreotide scan for neuroendocrine tumor (NET) also received cardiac SPECT. Angiography was performed within 1 month after SRS for 19 patients who showed intensive uptake in SRS and had cardiac risk factors. Of 52 patients who underwent MPI and SRS, 15 showed intensive cardiac uptake in SRS. Moreover, of 43 patients who were referred for NET, 4 patients had marked cardiac uptake in SRS in the heart. Nineteen patients including 12 women and 7 men aged 28 to 84 (58±8.04) years underwent coronary angiography. SRS and angiography in the left anterior descending territory were concordant in 15/19 (79%) patients, whereas only 7/15 (46%) cases had concordant MPI and angiography results. In the right coronary artery territory, SRS and angiography were concordant in 16/19 (84%) cases, while MPI and angiography were concordant in 11/15 (73%) cases. In the left circumflex artery territory, SRS and angiography were concordant in 15/19 (79%) cases, whereas MPI and angiography were concordant in 6/15 (40%) cases. In the remaining 76 patients who did not undergo coronary angiography based on cardiovascular profile and SRS, no cardiac events occurred in a follow-up of 2-11 months (7.52±2.71). Tc-99m-octreotide uptake was more concordant with coronary plaques relative to MPI findings, suggesting a potential role for Tc-99m-octreotide in the evaluation of atherosclerosis.

Automated identification of myocardial perfusion defects in dynamic cardiac computed tomography using deep learning

PurposeThe purpose of this study was to develop and evaluate deep convolutional neural network (CNN) models for quantifying myocardial blood flow (MBF) as well as for identifying myocardial perfusion defects in dynamic cardiac computed tomography (CT) images. MethodsAdenosine stress cardiac CT perfusion data acquired from 156 patients having or being suspected with coronary artery disease were considered for model development and validation. U-net-based deep CNN models were developed to segment the aorta and myocardium and to localize anatomical landmarks. Color-coded MBF maps were obtained in short-axis slices from the apex to the base level and were used to train a deep CNN classifier. Three binary classification models were built for the detection of perfusion defect in the left anterior descending artery (LAD), the right coronary artery (RCA), and the left circumflex artery (LCX) territories. ResultsMean Dice scores were 0.94 (±0.07) and 0.86 (±0.06) for the aorta and myocardial deep learning-based segmentations, respectively. With the localization U-net, mean distance errors were 3.5 (±3.5) mm and 3.8 (±2.4) mm for the basal and apical center points, respectively. The classification models identified perfusion defects with the accuracy of mean area under the receiver operating curve (AUROC) values of 0.959 (±0.023) for LAD, 0.949 (±0.016) for RCA, and 0.957 (±0.021) for LCX. ConclusionThe presented method has the potential to fully automate the quantification of MBF and subsequently identify the main coronary artery territories with myocardial perfusion defects in dynamic cardiac CT perfusion.

Clinical utility of reverse perfusion pattern with 99mTc myocardial stress perfusion scintigraphy

Abstract Background: Reverse distribution is a pattern that is occasionally observed with 99mTc sestamibi myocardial stress perfusion scintigraphy. The actual cause for this kind of pattern to occur is still under evaluation with no specific aetiology identified. Methods: We retrospectively studied 1195 patients who underwent 99mTc sestamibi myocardial stress perfusion scintigraphy. There was no history of acute myocardial infraction 1 month before the scan; no prior percutaneous transluminal coronary angioplasty was performed in any of these patients. Twenty-seven patients (2.2%) were found to have reverse distribution pattern based on the criteria after ruling out artefacts. Results: Their mean age was 53.5 ± 10.4 years; there were 18 females. Their mean body mass index (BMI) was 27.6 ± 3.4 kg/m2. Six patients had a history of hypertension, 4 patients had a history of diabetes mellitus and 2 patients had both before the scan. Scan findings suggested low probability for coronary artery disease (CAD) in 24 patients and high probability for CAD in three patients. Left anterior descending artery (LAD) territory, posterior descending artery and left circumflex (LCX) artery territory were involved in 22, 8 and 1 patient respectively. The mean time of follow-up was 36.3 ± 4.3 months. None of the patients later had any recurrent episode of chest pain or worsening of symptoms or sentinel events such as death after the scan. Conclusions: Reverse distribution pattern is sometimes observed with 99mTc-MIBI stress MPI. Such a finding has minimal prognostic significance, especially in patients with low and intermediate probability for CAD on imaging.

Bypass Grafting to Circumflex: Left Internal Thoracic Artery versus Saphenous Vein.

This study aimed to compare the short- and long-term outcomes of saphenous vein grafts (SVGs) and in situ left internal thoracic artery (LITA) grafts to the left circumflex artery (LCX) territory. This study included 678 patients who underwent LITA-left anterior descending (LAD) + SVG-LCX grafts and 286 patients who underwent right internal thoracic artery (RITA)-LAD + in situ LITA-LCX grafts from January 2002 to December 2020. Short-term and long-term clinical outcomes were compared using inverse probability of treatment weighting adjustment to reduce selection bias. In-hospital mortality was significantly higher for the SVG-LCX group (p = 0.008), whereas deep sternal wound infection was significantly higher in the LITA-LCX group (p = 0.013).Survival rates at 5 and 10 years were 83.12 and 71.45% in the SVG-LCX group, whereas 75.24 and 65.54% in the LITA-LCX group (log-rank p = 0.114). Rates of freedom from cardiac events at 5 and 10 years were 92.82 and 85.24% in the SVG-LCX group, whereas 94.89 and 89.46% in the LITA-LCX group (log-rank p = 0.179).Univariate and multivariate logistic regression analysis showed that proximal severe stenosis was significantly protective against graft dysfunction before discharge (odds ratio, 0.43; 95% confidence interval, 0.23-0.81). Deep sternal wound infection was significantly higher for LITA to LCX bypass whereas in-hospital mortality was higher for SVG to LCX. In situ LITA to LCX bypass grafting exhibited similar long-term outcomes with SVG to LCX bypass grafting in adjusted patient cohorts. Proximal severe stenosis of LCX was protective against graft dysfunction.

Long-term patency of bilateral internal thoracic artery Y composite coronary artery bypass grafts—determinants and impact on survival

BackgroundBilateral internal thoracic artery Y-composite grafting with sequential anastomoses is a well-established strategy for multi-arterial coronary artery bypass grafting. This study investigated the factors affecting long-term patency of bilateral internal thoracic artery Y-composite grafts and their influence on survival.MethodsPatients who underwent coronary artery bypass grafting using bilateral internal thoracic artery Y-composite grafts due to triple-vessel disease were included. In total, 415 cases (2003–2020) with at least 1 postoperative coronary computed tomography or angiography examination were enrolled. Through a retrospective review of medical records and computed tomography, risk factors for graft events (string sign or occlusion) were analysed, and the influence of string sign or occlusion in the initial postoperative computed tomography on long-term survival was evaluated.ResultsPatients’ mean age was 66±9 years and 324 were male (78%). The mean number of anastomoses from bilateral internal thoracic artery grafts was 4.0±0.9. The mean follow-up duration was 8.0±4.0 years (interquartile range: 4.8–11.5 years). Beating-heart surgery negatively affected the patency of grafts to the left circumflex and right coronary artery territories (P=0.015 and P=0.030, respectively), but in the left anterior descending territory, the graft patency did not differ (P=0.053). Non-severe (<90%) native-vessel stenosis was a risk factor for poor patency in the left anterior descending, left circumflex, and right coronary artery territories (P<0.001 for all). Twenty-four of the 104 nonvisible or narrowed grafts (23%) on early imaging later became widely patent. Occlusion of the grafts or the string sign within postoperative 1 year did not have a negative impact on long-term survival (P=0.421).ConclusionsThe patency rate was suboptimal in case of non-severe target-vessel stenosis (<90%). The beating-heart technique may negatively influence the patency of anastomoses to the left circumflex and right coronary artery territories. Compromised graft patency observed on initial computed tomography did not lead to worse survival.

A Comparison Between Two-Dimensional and Three-Dimensional Regional and Global Longitudinal Strain Echocardiography to Evaluate Complex Coronary Lesions in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome.

IntroductionA preliminary assessment of patients who suffer from severe and complex coronary artery lesions, such as three-vessel disease and/or a left main (LM) artery lesion, plays a critical contribution in determining prognosis and treatment plans for non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Therefore, a pre-angiography (i.e., before angiography) predictor was required to cost-effectively evaluate severe and complex coronary lesions to efficiently direct our subsequent dealing.AimThis study aimed to compare two-dimensional (2D) and three-dimensional (3D) global longitudinal strain (GLS) at the regional level to assess extremely complicated coronary lesions using the SYNTAX score as a standard of reference in 100 patients with NSTE-ACS.Materials and methodsThis research included 100 patients with non-ST-segment elevation acute coronary syndrome who presented at the Cardiology Department at Fayoum University from December 2019 to July 2020. All patients underwent a complete history and physical examination, hemoglobin A1c (HbA1c), lipid profile, creatinine assessment, 12-lead electrocardiogram (ECG), and transthoracic echocardiography (TTE) to detect global and regional longitudinal strain by 2D and 3D speckle-tracking echocardiography (STE). Coronary angiography was done on all patients within 24 hours of admission after acquiring echo images. Then, the results of 2D and 3D regional and global longitudinal strain (GLS) to predict the severity and coronary lesion complexity in terms of the SYNTAX score were compared.ResultsThis study revealed that 2D GLS was −12.10 ± 3.51, which is significantly higher than 3D GLS of −11.64 ± 4.05 (p < 0. 001). The left anterior descending coronary artery (LAD) and left circumflex artery (LCX) territories revealed a significantly higher value using 2D regional longitudinal strain (−11.13 ± 4.47 and −12.54 ± 4.11, respectively) than using 3D regional longitudinal strain (−10.84 ± 5.18 and −12.05 ± 4.29, respectively) (p= 0.017 and p < 0.001, respectively). There were significantly lower 2D GLS, 3D GLS, global circumferential strain (GCS), area strain, and global radial strain (GRS) in the intermediate and high score group than in the low score group of patients (p < 0.001 for all).Conclusion2D and 3D strain echocardiography including GLS, GCS, GRS, and area strain are a noninvasive and rapid tool with clinical utility for evaluating coronary lesions in patients with NSTE-ACS. They can be routinely used to diagnose and stratify high-risk patients with NSTE-ACS, thereby potentially resulting in improved patient assessment. GLS as measured by 2D and 3D STE at minimal effort is a significant risk factor for patients with complex NSTE-ACS. In NSTE-ACS cases, the GLS absolute value is significantly associated with the degree of complexity of coronary artery lesions.

Electrocardiographic patterns predict the presence of collateral circulation and in-hospital mortality in acute total left main occlusion

BackgroundData on the clinical characteristics, electrocardiogram (ECG) findings and outcomes of patients with acute myocardial infarction (AMI) due to total unprotected left main (ULM) artery occlusion is limited.MethodsBetween 2009 and 2021, 44 patients with AMI due to total ULM occlusion underwent primary percutaneous coronary intervention (PCI) at our institution. The ECG, collateral circulation, clinical and procedural characteristics, and in-hospital mortality were retrospectively evaluated.ResultsTwenty five patients presented with shock and 18 patients had in-hospital mortality. Nineteen patients presented with ST-segment elevation myocardial infarction (STEMI), while 25 presented with non-ST-segment elevation myocardial infarction (NSTEMI). ST-segment elevation (STE) in I and STEMI were associated with the absence of collateral circulation, while STE in aVR was associated with its presence. In the NSTEMI group, patients with STE in both aVR and aVL showed more collateral filling of the left anterior descending coronary artery (LAD) territory, while patients with STE in aVR showed more collateral filling of the LAD and the left circumflex artery territory. Compared with total ULM occlusion, patients with partial ULM obstruction presented with more STE in aVR, less STE in aVR and aVL, and less STEMI. Shock, post-PCI TIMI 0–2 flow, non-STE in aVR, STEMI, and STE in I predicted in-hospital mortality. STEMI and the absence of collateral flow were significantly associated with shock.ConclusionsSTE in the precordial leads predicted the absence of collateral circulation while STE in aVR and STE in both aVR and aVL predicted different collateral filling territories in ULM occlusion. STE in I, non-STE in aVR, and STEMI predicted in-hospital mortality in these patients.

Effects of Mechanical Dyssynchrony on Coronary Flow: Insights From a Computational Model of Coupled Coronary Perfusion With Systemic Circulation.

Mechanical dyssynchrony affects left ventricular (LV) mechanics and coronary perfusion. Due to the confounding effects of their bi-directional interactions, the mechanisms behind these changes are difficult to isolate from experimental and clinical studies alone. Here, we develop and calibrate a closed-loop computational model that couples the systemic circulation, LV mechanics, and coronary perfusion. The model is applied to simulate the impact of mechanical dyssynchrony on coronary flow in the left anterior descending artery (LAD) and left circumflex artery (LCX) territories caused by regional alterations in perfusion pressure and intramyocardial pressure (IMP). We also investigate the effects of regional coronary flow alterations on regional LV contractility in mechanical dyssynchrony based on prescribed contractility-flow relationships without considering autoregulation. The model predicts that LCX and LAD flows are reduced by 7.2%, and increased by 17.1%, respectively, in mechanical dyssynchrony with a systolic dyssynchrony index of 10% when the LAD's IMP is synchronous with the arterial pressure. The LAD flow is reduced by 11.6% only when its IMP is delayed with respect to the arterial pressure by 0.07 s. When contractility is sensitive to coronary flow, mechanical dyssynchrony can affect global LV mechanics, IMPs and contractility that in turn, further affect the coronary flow in a feedback loop that results in a substantial reduction of dPLV/dt, indicative of ischemia. Taken together, these findings imply that regional IMPs play a significant role in affecting regional coronary flows in mechanical dyssynchrony and the changes in regional coronary flow may produce ischemia when contractility is sensitive to the changes in coronary flow.

Quantitative analysis of regional endocardial geometry dynamics from 4D cardiac CT images: endocardial tracking based on the iterative closest point with an integrated scale estimation

Regional cardiac function analysis is important for the diagnosis and treatment planning of ischemic heart disease, but has not been sufficiently developed in the field of computed tomography (CT). Therefore, we propose a 3D endocardial tracking framework for cardiac CT using local point cloud registration based on the iterative closest point with an integrated scale estimation algorithm. We also introduce regional function descriptors that express the curvature and stretching of the endocardium: Surface distortion (E) and Scaling rate (S). For a region-to-region comparison, we propose endocardial segmentation according to coronary perfusion territories defined by the Voronoi partition based on coronary distribution. Our study of 65 endocardial segments in ten subjects showed that global endocardial deformation has a positive relationship with the stroke volume index (r = 0.896 and 0.829 in and , respectively) and ejection fraction (r = 0.804 and 0.835), and a positive relationship with the brain natriuretic peptide level (r = 0.690 and 0.776). A positive relationship between segmental E and S (r = 0.845), a higher value of E in ischemic segments (p = 0.021) that are determined by fractional flow reserve estimated from coronary CT data, and a higher value of S in the left circumflex artery territory (p < 0.05) were also observed. The required radiation dose was 5.0 ± 0.7 mSv and the computation time was 7.2 ± 1.1 min. The result suggests that proposed endocardial deformation analysis using CT can be conducted on site and in time for the acute setting, and may be useful for the diagnosis of cardiac dysfunction or myocardial ischemia.

PET/CT scanning with 3D acquisition is feasible for quantifying myocardial blood flow when diagnosing coronary artery disease

BackgroundThe quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR) are useful approaches for evaluating the functional severity of coronary artery disease (CAD). 15O-water positron emission tomography (PET) is considered the gold standard method for MBF quantification. However, MBF measurements in 15O-water PET with three-dimensional (3D) data acquisition, attenuation correction using computed tomography (CT), and time of flight have not been investigated in detail or validated. We conducted this study to evaluate the diagnostic potential of MBF measurements using PET/CT for a comparison of a control group and patients suspected of having CAD.ResultsTwenty-four patients with known or suspected CAD and eight age-matched healthy volunteers underwent rest and pharmacological stress perfusion studies with 15O-water PET/CT. The whole and three regional (left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) territory) MBF values were estimated. The CFR was computed as the ratio of the MBF during adenosine triphosphate-induced stress to the MBF at rest. The inter-observer variability was assessed by two independent observers. PET/CT using a 15O-water dose of 500 MBq and 3D data acquisition showed good image quality. A strong inter-observer correlation was detected in both the whole MBF analysis and the regional analysis with high intra-class correlation coefficients (r > 0.90, p < 0.001). Regional MBF at rest (LAD, 0.82 ± 0.15 ml/min/g; LCX, 0.83 ± 0.17 ml/min/g; RCA, 0.71 ± 0.20 ml/min/g; p = 0.74), MBF at stress (LAD, 3.77 ± 1.00 ml/min/g; LCX, 3.56 ± 1.01 ml/min/g; RCA, 3.27 ± 1.04 ml/min/g; p = 0.62), and CFR (LAD, 4.64 ± 0.90; LCX, 4.30 ± 0.64; RCA, 4.64 ± 0.96; p = 0.66) of the healthy volunteers showed no significant difference among the three regions. The global CFR of the patients was significantly lower than that of the volunteers (2.75 ± 0.81 vs. 4.54 ± 0.66, p = 0.0002). The regional analysis of the patients demonstrated that the CFR tended to be lower in the stenotic region compared to the non-stenotic region (2.43 ± 0.81 vs. 2.95 ± 0.92, p = 0.052).Conclusions15O-water PET/CT with 3D data acquisition can be reliably used for the quantification of functional MBF and CFR in CAD patients.

Residual Activity Correction in Quantitative Myocardial Perfusion 13N-Ammonia PET Imaging: A Study in Post-MI Patients

Background/Introduction/AimPositron emission tomography (PET) is the gold standard for the quantification of myocardial blood flow (MBF). A standard PET scan is acquired in two phases (rest and pharmacological stress). 13N-ammonia is a perfusion radiotracer that may show residual activity, which may affect MBF estimation during the second phase of the scan. An algorithm for residual activity correction (RAC) is available when reconstruction is performed using Syngo MBF (by Siemens). The aim of this study was to evaluate differences in MBF estimation with and without RAC by Syngo MBF in patients with a previous MI using 13N-ammonia PET. MethodsMBF was evaluated by 13N-ammonia PET in a group of 25 patients with a history of MI. Dynamic MBF measurements were analyzed with Syngo Dynamic PET, with and without RAC, and the results were evaluated with statistical methods. ResultsSignificant differences in stress phase MBF after RAC were identified in the left anterior descending coronary artery (LAD) territory (p=0.0425) and the right coronary artery (RCA) territory (p=0.004). A trend towards significance was identified in the global polar plot (p=0.049). No statistically significant difference was found in the left circumflex artery (LCx) territory (p=0.333). ConclusionSyngo Dynamic PET, through its RAC function, can be a useful adjunct in assessing second-phase MBF of primarily the RCA territory and secondarily the global polar plot and LAD territory but not the LCx territory.

Anatomical study of the internal thoracic arteries; implications for use in coronary artery bypass graft surgery.

The feasibility of coronary artery bypass grafting using an internal thoracic artery (ITA) depends on the length of the graft with respect to the optimal route to reach the coronary target. The goal of this study was to assess the gain in length afforded by skeletonization and to evaluate the lengths of different pathways of the ITAs to the left coronary arteries. The left and right ITAs were dissected out from 20 specimens and measured before and after skeletonization. Distance between the origin of the right ITA and the base of the left atrial appendage, corresponding to the proximal circumflex artery, was measured for both the transverse pericardial sinus and preaortic routes. Skeletonization gave a significant gain of length for both ITAs. Analysis showed no significant correlation between the ITA length and the height, weight, and BMI of specimens. We found no association between the length of the sternum and the length of skeletonized RITA or LITA. The anterior route of the skeletonized right ITA was shorter than the transverse pericardial sinus route in 18 cases. The average length to the circumflex artery territory was 132.8±23.5mm in front of the aorta and 150.5±18.8 through the transverse pericardial sinus with a gain of length of 17.7mm (p<0.0001). Skeletonization gave significant gains in length of both ITAs. The preaortic route for the skeletonized right ITA toward the circumflex territory was shorter than the transverse pericardial sinus route in 90% of cases.

Asymptomatic fatal post-lobectomy hemopericardium

We report a case of an asymptomatic post-lobectomy hemopericardium in a female who died suddenly at day two post surgery. Autopsy revealed no pathologic findings, but 250 ml of blood and clots in the pericardium and a non-significant injury to the epicardial fat overlying the circumflex artery territory.

Comparison between off-pump and on-pump coronary artery bypass grafting in patients with severe lesions at the circumflex artery territory: 5-year follow-up of the MASS III trial.

The technical difficulty in the revascularization of the circumflex artery territory with off-pump surgery may compromise the outcome of this method in clinical follow-up. We aimed to evaluate cardiac events in patients with stable coronary artery disease and severe obstruction of the circumflex system, undergoing coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass. MASS III was a single-centre study that evaluated 308 patients with multivessel coronary artery disease randomized to on-pump (153) or off-pump (155) CABG. Of this total, 260 (84.4%) patients had, on coronary angiography, at least one 70% obstruction in the circumflex territory (141 on-pump and 119 off-pump). The combined outcome was death, myocardial infarction, target vessel revascularization (angioplasty or surgery) or hospitalization for cardiac causes. Variables with possible associations (P < 0.1) were included in the multivariate analysis. The two groups were well matched for demographics and clinical and angiographic characteristics. After 5 years of follow-up, off-pump CABG had higher combined events than on-pump had: 25 (21%) vs 17 (12%), hazard ratio 1.88, 95% confidence interval 1.02-3.48, P = 0.041. In the multivariate model with the inclusion of the following variables: age (P = 0.09) and complete revascularization (P = 0.68), off-pump surgery remained as a predictor of combined events in 5 years, P = 0.03. In patients with multivessel coronary artery disease and severe lesions in the circumflex territory, off-pump coronary artery bypass surgery resulted in a higher incidence of cardiac events at 5-year follow-up. ISRCTN59539154 (http://www.controlled-trials.com).

Preclinical Evaluation of Biopolymer-Delivered Circulating Angiogenic Cells in a Swine Model of Hibernating Myocardium

Vasculogenic cell-based therapy combined with tissue engineering is a promising revascularization approach targeted at patients with advanced coronary artery disease, many of whom exhibit myocardial hibernation. However, to date, no experimental data have been available in this context; we therefore examined the biopolymer-supported delivery of circulating angiogenic cells using a clinically relevant swine model of hibernating myocardium. Twenty-five swine underwent placement of an ameroid constrictor on the left circumflex artery. After 2 weeks, animals underwent echocardiography, rest and stress ammonia-positron emission tomography perfusion, and fluorodeoxyglucose positron emission tomography viability scans. The following week, swine were randomized to receive intramyocardial injections of PBS control (n=10), circulating angiogenic cells (n=8), or circulating angiogenic cells+collagen-based matrix (n=7). The imaging protocol was repeated after 7 weeks. Baseline positron emission tomography myocardial blood flow and myocardial flow reserve were reduced in the left circumflex artery territory (both P<0.001), and hibernation (mismatch) was observed. At follow-up, stress myocardial blood flow had increased (P≤0.01) and hibernation decreased (P<0.01) in the cells+matrix group only. Microsphere-measured myocardial blood flow validated the perfusion results. Arteriole density and wall motion abnormalities improved in the cells+matrix group. There was also a strong trend toward an improvement in ejection fraction (P=0.07). In this preclinical swine model of ischemic and hibernating myocardium, the combined delivery of circulating angiogenic cells and a collagen-based matrix restored perfusion, reduced hibernation, and improved myocardial wall motion.

Comparison between off-pump and on-pump coronary artery bypass grafting in patients with severe lesions at the circumflex artery territory: 5-year follow-up of the MASS III trial

Background: Several studies comparing Off-Pump Coronary Artery Bypass surgery (OPCAB) with On-Pump (ONCAB), in various patients populations, fail to demonstrate a superiority of a technique over the other in long term outcomes. The technical difficulty in the revascularization of the Circumflex Artery (CXA) territory with off-pump surgery may compromise the outcome of this method in clinical follow-up. Objective: To evaluate cardiac events in patients with stable Coronary Artery Disease (CAD) that had an obstruction on CXA (or their major branches) greater than 70% undergoing CABG with or without cardiopulmonary bypass. Methods: The MASS III was a single-center study that evaluated 308 patients with multivessel CAD and preserved ejection fraction randomized to ONCAB (153) or OPCAB (155). Of this total, 260 (84.4%) patients had on coronary angiography at least a 70% obstruction in the circumflex artery territory. (141 ONCAB and 119 OPCAB). The combined outcome was death, myocardial infarction, target vessel revascularization (angioplasty or surgery), or hospitalization for cardiac causes. Variables with possible association (P <0.2) were included in multivariate analysis. Results: The two groups were well matched for demographics, clinical and angiographic characteristics. After 5 years of follow up, OPCAB had higher combined events than ONCAB: 25 (21%) vs 17 (12%), hazard ratio 1.88, 95% CI 1.02 to 3.48, P = 0.041. In the multivariate model the following variables were included: age (P = 0.09) and presence of diabetes (P = 0.18). OPCAB remained as a predictor of combined events in 5 years, P = 0.032. There was no advantages of complete revascularization over incomplete revascularization in the combined endpoint at 5 years: 22 (17.1%) vs 20 (15.3%) P = 0.68, respectively. Conclusions: In patients with multivessel CAD and severe lesions in the CXA territory, off-pump coronary bypass surgery resulted in a higher frequency of cardiac events in 5 years, regardless of achieving complete revascularization.

Isolated Anomalous Origin of the Right Coronary Artery From the Pulmonary Artery in an Asymptomatic 12-Year-Old Girl: Role of MRI in Depicting the Anatomy, Detecting the Ischemic Burden, and Quantifying the Amount of Left-to-Right Shunt

Asymptomatic 12-year-old girl with a heart murmur underwent echocardiogram and suspicious continuous flow was detected in her interventricular septum. She underwent cardiac magnetic resonance (CMR) for further investigation. The CMR images demonstrated anomalous origin of the right coronary artery from the pulmonary artery. Adenosine stress perfusion scan showed an inducible perfusion defect in the right coronary artery and left circumflex artery territories. Flow quantification showed a left-to-right shunt with pulmonary to systemic blood flow ratio (Qp/Qs) of 1.25.