ABSTRACT
Background: Vein graft thrombosis is the leading cause of acute graft failure within the first post-operative month. Several studies have shown the benefit of post-operative dual anti-platelet therapy (DAPT) in preventing acute graft thrombosis. The purpose of this study was to determine whether peri-operative initiation of DAPT will improve short and intermediate term graft patency. Methods: This was a randomized, double-blind, placebo controlled trial of 20 patients undergoing CABG to compare DAPT versus aspirin monotherapy. The primary outcome was post-operative graft patency at 2 and 52 weeks determined by <50% bypass graft stenosis by cardiac computed tomography angiography (CCTA). The secondary outcomes were (1) major adverse cardiovascular events (MACE), defined as myocardial infarction, thrombotic events, and angina, and (2) safety end-points defined as TIMI major and minor bleeding events. Results: The study population consisted predominately of men (19/20 patients). At 2 weeks, all LIMA grafts were patent although vein graft patency for the DAPT group was only 83.3% (20/24) compared to 89.5% (17/19) for placebo (p=0.597). At 52 weeks, the patency rate in the placebo group was 52.6% (10/19) as compared to a patency of 71.4% (15/24) in the dual anti-platelet therapy arm (p=0.244). Conclusion: The addition of clopidogrel to aspirin post-bypass surgery did not significantly improve venous graft patency at 2 weeks but trended toward higher graft patency at 52 weeks.
ABSTRACT
A 51-year-old male with a family history of premature coronary artery disease (CAD) presented with acute myocardial infarction (AMI) with coronary angiography demonstrating no angiographic disease and a mid-left anterior descending (LAD) myocardial bridging (MB) segment with 71% mean lumen diameter (MLD) compression. Due to continually rising biomarkers and recurrent angina, cardiac magnetic resonance imaging(CMR) was obtained demonstrating late gadolinium enhancement (LGE) involving the mid-distal LAD territory. Patient subsequently underwent successful percutaneous coronary intervention (PCI) with drug-eluting stent (DES) to the MB segment with resolution of symptoms, which persisted over a year. MBis defined as an intramuscular segment resulting in overlying bands of myocardium, also called “tunneled” artery. Once thought benign, MB has been reported to cause unstable angina, AMI, life-threatening arrhythmias, and sudden cardiac death. PCI has been reported to relieve symptoms balanced against rates of in-stent restenosis and target lesion revascularization as high as 19% with DES. This case illustrates the utility of CMR in the setting of AMI to guide decision to purse PCI in symptomatic MB.
ABSTRACT
Background: Atherosclerotic vascular disease remains a significant etiology of morbidity and mortality in the United States. Coronary artery calcium (CAC) is associated with increased stroke incidence and coronary atherosclerotic burden. Uncertainty remains regarding how best to interpret non-zero CAC scores, particularly in symptomatic patients. Methods: A review of the first 1122 patients who underwent coronary CT angiography (CCTA) with CAC scoring from January 2005 until July 2012 was performed. Patients were dichotomized into 2 groups, zero CAC score and non-zero CAC score. Non-zero CAC patients were further subdivided based on the specific coronary artery containing calcium. Rates of major adverse cardiovascular events (MACE) defined as all-cause mortality, non-fatal myocardial infarction (MI), ischemic stroke, and late revascularization (>90 days following CCTA) were evaluated in each group. Results: 505 patients (63% male, mean age 60 ± 11) with non-zero CAC scores were analyzed over a six year period with resultant median follow up period of 22 months (IQR25,75 13-34 months). Major adverse cardiovascular events were observed in 11 patients. Receiver-operator curve (ROC) analysis on each coronary segment showed significance with the presence of left main (LM) CAC (AUC 0.752, p=0.004). Conclusions: The presence of CAC at any value in the LM in this case series appears to predispose patients to increased rates of MACE.
ABSTRACT
Background: The use of noninvasive medical imaging has increased over the past decade at a cost of significant lifetime radiation exposure to study subjects. We report the implementation of radiation dose reduction methods and associated reduction in ionizing radiation exposure with Coronary Computed Tomography Angiography (CCTA) over time. Methods: Radiation doses and total number of studies performed were evaluated constantly from January 2010 to September 2012 for CCTA (N=2613), as well as Single photon emission computed tomography (SPECT, N=8060) part of an ongoing effort to minimize radiation exposure. Analysis of variance was used to evaluate the radiation exposure reduction among modalities. We compared CCTA radiation doses in the era of retrospective protocols coupled with dose modulation (40%-80%phase) using Siemens® 64-slice Dual Source technology, with prospective scanning on the same equipment, as well as radiation doses on the newer Siemens® Flash Equipment and the implementation of nursing/technologist aggressively driven protocol for heart rate control and image acquisition independent of imaging provider presence during acquisition. Results: The radiation dose reduction with implementation of multiple measures of radiation reduction to include physician independent-technician driven CCTA protocol resulted in a reduction from mean of 9.85±5.96 (median 8.8mSv) to mean of 3.00±2.53(median 2.1mSv) (p<0.0001). CCTA radiation dose has decreased by 69.2% since January of 2010 while SPECT radiation dose remained constant at 14mSv (p<0.0001). Conclusion: Continued advances in software and hardware technology, combined with “physician independent-technician driven” CCTA protocol have drastically reduced radiation dosing in CCTA to annual background radiation exposure, while maximizing the benefit of the study and without sacrificing patient safety.