Incidental Coronary Artery Calcium on Breast Radiation Therapy Planning Scans Identifies Patients for Cardiac Preventive Therapy.

PURPOSE/OBJECTIVE(S): The presence of coronary artery calcium (CAC>0) is associated with increased cardiac-related mortality and is a common indication to initiate statin therapy to prevent future long-term cardiac-related adverse events. CAC is also well visualized on noncontrast chest computed tomography simulation (CT sim) scans used for breast radiation planning. We hypothesize that by screening for incidental CAC on CT sims, radiation oncologists could help identify patients who may benefit from additional preventive medical interventions with their primary care physician or cardiologist. METHODS: A retrospective analysis of 126 consecutive patients with breast cancer treated with external beam radiation therapy at a single institution was performed. Noncontrast CT sim scans were reviewed for the presence of CAC and the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) was calculated to identify patients who may benefit from initiating statin therapy. Patients with CAC>0 and/or ASCVD risk >20% were identified as those who may benefit from statin therapy. RESULTS: Out of 72 patients with CAC>0, only 12(16%) had reported pre-existing coronary artery disease and 32(44%) were not already on recommended statin therapy. CAC>0 visualized on CT sim was able to identify 29 additional patients who would benefit from statin beyond what the ASCVD risk calculator could identify. CONCLUSION: Observation of incidental CAC on breast radiation-planning CT scans identified patients who could benefit from cardiac-related preventive strategies. By increasing attention, awareness, and reporting of incidental CAC visible on CT sims, radiation oncologists may fulfill a unique role to bridge a potential gap in cardiovascular preventive medicine.

Perioperative management of aspirin resistance after off-pump coronary artery bypass grafting: possible role for aprotinin.

BACKGROUND: Aspirin is the only drug proven to reduce saphenous vein graft (SVG) failure, but aspirin resistance (ASA-R) frequently occurs after off-pump coronary artery bypass grafting (OPCAB). The factors, mechanism, and best means for preventing and/or treating ASA-R have not been established. This study hypothesizes that thrombin production during OPCAB stimulates this acquired ASA-R. STUDY DESIGN AND METHODS: A nonrandomized prospective cohort of 255 patients (n=465 SVG) who underwent OPCAB with varied use of aprotinin (21%) and different SVG preparation techniques (standard, 56% vs. low-pressure, 44%) was analyzed. A surplus SVG segment was obtained to assess endothelial integrity. ASA-R was determined at baseline, after surgery, and on Days 1 and 3 by three assays. The effects of aprotinin on thrombin responsiveness were analyzed by means of whole-blood aggregometry, SVG tissue factor (TF) activity, and transcardiac thrombin production (i.e., F1.2 levels in aorta versus coronary sinus). SVG patency was assessed on Day 5 with multichannel CT angiography. RESULTS: ASA-R developed in 42 percent of patients after OPCAB. Multivariate analysis showed that ASA-R, endothelial integrity, and target size independently predicted early SVG failure. Aprotinin use was associated with: 1) reduced postoperative ASA-R (15%); 2) decreased platelet (PLT) response to thrombin; 3) reduced TF activity within SVG segments; 4) decreased transcardiac thrombin gradient; and 5) improved SVG patency. CONCLUSION: ASA-R is a common post-OPCAB event whose frequency may be reduced by intraoperative use of aprotinin, possibly via TF and thrombin suppression. Improved perioperative PLT function after OPCAB may also inadvertently enhance the clinical relevance of these potential antithrombotic effects.

Off-Pump Coronary Artery Bypass Leads to a Regional Hypercoagulable State Not Detectable Using Systemic Markers.

OBJECTIVE: It is believed that off-pump coronary artery bypass grafting (OPCAB) leads to hypercoagulability, but efforts to document such a state have been unrevealing. We hypothesized that OPCAB increases the risk of developing a regional hypercoagulable state. METHODS: Blood was obtained from the aorta and coronary sinus (CS) after CABG performed off- (N=69) or on-pump (N=35) to determine the transcardiac gradients of F1.2 (thrombin production), XIIa (coagulation activation), myoglobin (ischemia) and IL-6, IL-8 using ELISA and platelet-derived microparticles using FACS. Platelet function was measured using aggregometry. Regional myocardial pH and SVG flow were recorded intraoperatively. SVG biopsies were analyzed for endothelial integrity (EI) using immunohistochemistry and graft patency was determined by predischarge CT angiography. RESULTS: Compared with on-pump, OPCAB provoked significantly higher transcardiac F1.2 (117±200 v. 31±38%), FXII-a (14±29 v. 2±4%), microparticles (14±-9.5% v. 6.4±-4.1%), IL-6 (119±183 v. 28±39%), and a trend toward increased IL-8 (67±94 v. 24±46%, P = 0.077). Myoglobin release after OPCAB, also greater than on-pump CABG (54±89 v. 8±14%, P < 0.01), correlated with regional pH change (R=-0.96, P < 0.0001), and F1.2 release (R=0.55, P = 0.0002). In contrast, systemic changes in these markers were all less after OPCAB. SVG flow was significantly reduced in OPCAB (39.4 versus 66.5 mL/min, P = 0.0002), but EI and graft patency rates were the same. CONCLUSIONS: Through the use of transcardiac assays, we illustrated that regional coagulation was enhanced after off- compared with on-pump CABG. If the findings of this pilot study are confirmed, OPCAB may require additional antithrombotic therapies to respond to this local hypercoagulable state.

A multi-institutional experience with the CryoMaze procedure.

BACKGROUND: The Cox Maze III operation remains the gold standard for the surgical treatment of atrial fibrillation (AF). We report our experience using a flexible argon-powered metal cryoprobe for creation of the complete Cox-Maze III lesion set in patients with AF (the CryoMaze operation). METHODS: Beginning July 2002, 38 patients underwent the CryoMaze operation. Two patients had isolated CryoMaze procedures, whereas 36 patients had the CryoMaze performed in combination with coronary, valvular, or aortic surgery. All patients had electrocardiographic follow-up. Atrial fibrillation was continuous in 79%. Mean duration of AF before operation was 48 months. RESULTS: There were no complications related to the use of cryoenergy. There was 1 hospital death (2.6%) and no late deaths. At a mean follow-up of 12 months, 35 of 37 patients (95%) were in normal sinus rhythm. One patient required pacemaker implantation 3 months after surgery, and 1 patient refused follow-up. There have been no early or late thromboembolic events. CONCLUSIONS: The CryoMaze operation reliably cures atrial fibrillation at medium term follow-up, with rates identical to those reported for the classic Cox-Maze III operation.

Disruption of graft endothelium correlates with early failure after off-pump coronary artery bypass surgery.

BACKGROUND: Saphenous vein graft failure after coronary artery bypass surgery may be as high as 5% to 10% in the first postoperative week. We hypothesized that identifying damage sustained by saphenous vein endothelium before grafting predicts early graft attrition after off-pump coronary artery bypass graft surgery. METHODS: Intraoperative graft flow, platelet function, and endothelial integrity were analyzed in 125 patients undergoing off-pump coronary artery bypass graft surgery. Endothelial integrity was assessed in an excess vein segment from each graft using immunohistochemistry (CD31 staining). Platelet function was monitored just before and immediately after revascularization and on postoperative days 1 and 3 using whole blood aggregometry, thrombelastography, and platelet activated clotting time. Platelet activation was monitored using flow cytometry. Intraoperative conduit blood flow, measured by transit time ultrasonography, was used to detect and rectify anastomotic problems. Early graft patency was determined on postoperative day 5 using gated multichannel computed tomography angiography. RESULTS: In 106 patients undergoing postoperative computed tomography evaluation, 10 vein grafts in 10 patients were discovered to have developed early thrombosis, representing 4% (10 of 217) of all vein grafts. Endothelial integrity was 10.75% +/- 17.56% in 10 grafts that failed early compared with 51.45% +/- 36.29% in patent grafts (p = 0.04). Perioperative platelet function and graft flow did not differ significantly between the two groups. CONCLUSIONS: Although endothelial disruption predicts early failure of bypass grafts, the importance of a hypercoaguable state and low graft flow as a cause of early graft thrombosis after off-pump coronary artery bypass graft surgery was not supported by our preliminary results. A means to assess, prevent, and treat intraoperative vein graft damage will likely improve early graft patency.