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Biomedical subjects

John D Carroll

Publications and source records attributed to John D Carroll.

At least 19 recordsLinked to original sources

Impact of in-hospital acquired thrombocytopenia in patients undergoing primary angioplasty for acute myocardial infarction.

Thrombocytopenia that develops after percutaneous coronary intervention (PCI) may result in hemorrhagic complications, requirement for blood product transfusions, and potentially thrombotic or ischemic complications. The incidence and prognostic significance of thrombocytopenia, in patients with acute myocardial infarction (AMI) who undergo primary PCI have not been evaluated. In the CADILLAC trial 2,082 patients who had AMI within 12 hours of onset without shock were prospectively randomized to receive balloon angioplasty with or without abciximab versus stenting with or without abciximab. Acquired thrombocytopenia, defined as a nadir platelet count <100 x 10(9)/L in patients who did not have baseline thrombocytopenia, developed in 50 of 1,975 qualifying patients (2.5%) after primary PCI. By multivariate analysis, acquired thrombocytopenia developed more frequently in patients who had non-insulin-requiring diabetes mellitus (odds ratio 3.88 [OR], p = 0.0002), previous statin administration (OR 3.28, p = 0.002), and use of abciximab (OR 2.06, p = 0.02) and less frequently in patients who had previous aspirin use (OR 0.26, p = 0.002), a higher baseline platelet count (OR 1.20, p < 0.0001), and greater body mass index (OR 0.90, p = 0.006). Patients who developed thrombocytopenia versus those who did not had higher in-hospital rates of major hemorrhagic complications (10.0% vs 2.7%, p = 0.01), greater requirement for blood transfusions (10.0% vs 3.9%, p = 0.05), longer hospital stay (median 4.8 vs 3.6 days, p = 0.008), and increased costs (median dollar 14,466 vs dollar 11,629, p = 0.001). All-cause mortality was markedly increased at 30 days (8.0% vs 1.6%, p = 0.0008) and at 1 year (10.0% vs 3.9%, p = 0.03) in patients who developed thrombocytopenia. In conclusion, thrombocytopenia that develops after primary PCI for AMI, although uncommon, is associated with increased hemorrhagic complications and decreased survival.

Abciximab↗

Angiographic views used for percutaneous coronary interventions: a three-dimensional analysis of physician-determined vs. computer-generated views.

The goal of this study was to determine the severity of vessel foreshortening in standard angiographic views used during percutaneous coronary intervention (PCI). Coronary angiography is limited by its two-dimensional (2D) representation of three-dimensional (3D) structures. Vessel foreshortening in angiographic images may cause errors in the assessment of lesions or the selection and placement of stents. To date, no technique has existed to quantify these 2D limitations or the performance of physicians in selecting angiographic views. Stent deployment was performed in 156 vessel segments in 149 patients. Using 3D reconstruction models of each patient's coronary tree, vessel foreshortening was measured in the actual working view used for stent deployment. A computer-generated optimal view was then identified for each vessel segment and compared to the working view. Vessel foreshortening ranged from 0 to 50% in the 156 working views used for stent deployment and varied by coronary artery and by vessel segment within each artery. In general, views of the mid circumflex artery were the most foreshortened and views of the right coronary artery were the least foreshortened. Expert-recommended views frequently resulted in more foreshortening than computer-generated optimal views, which had only 0.5% +/- 1.2% foreshortening with < 2% overlap for the same 156 segments. Optimal views differed from the operator-selected working views by > or = 10 degrees in over 90% of vessels and frequently occurred in entirely different imaging quadrants. Vessel foreshortening occurs frequently in standard angiographic projections during stent deployment. If unrecognized by the operator, vessel foreshortening may result in suboptimal clinical results. Modifications to expert-recommended views using 3D reconstruction may improve visualization and the accuracy of stent deployment. These results highlight the limitations of 2D angiography and support the development of real-time 3D techniques to improve visualization during PCI.

Adult↗

Percutaneous closure of ascending aortic pseudoaneurysm using Amplatzer septal occluder device: the first clinical case report and literature review.

We report the first case of the use of an Amplatzer septal occluder device to close a large ascending aortic pseudoaneurysm. The patient had a complex cardiac history with redo coronary artery bypass graft surgery, severe left ventricular dysfunction, and end-stage renal disease requiring hemodialysis. The procedure was successfully performed under fluoroscopic and 2D/3D transthoracic echocardiographic guidance. Six-week follow-up with both transthoracic echocardiography and MRI showed the device was in proper position with complete closure of the pseudoaneurysm.

Aneurysm, False↗

Antiphospholipid antibodies are common in patients referred for percutaneous patent foramen ovale closure.

Very little is known about any interaction between patent foramen ovale (PFO) and various hypercoagulable disorders that have been associated with cryptogenic stroke. Percutaneous PFO closure for secondary prevention of paradoxical thromboembolization is receiving increasing attention. Hypercoagulability may affect the potential risks and expected benefits of percutaneous PFO closure. Consecutive patients undergoing percutaneous PFO closure at a single center were screened for the presence of antiphospholipid antibodies, elevated lipoprotein(a), hyperhomocysteinemia, and dysfibrinogenemia. Sixteen of 34 patients (47%) with complete arterial hypercoagulability screening had laboratory evidence of arterial hypercoagulability. Thirteen of these patients (38%) had antiphospholipid antibodies. Antiphospholipid antibodies appear to be common in patients referred for percutaneous PFO closure for secondary prevention of systemic thromboembolic events. Thorough testing based on established recommendations is warranted. Further studies are needed regarding the interaction between PFO and various hypercoagulable disorders that have been associated with cryptogenic stroke.

Adult↗

Randomized study of the safety and clinical utility of rotational angiography versus standard angiography in the diagnosis of coronary artery disease.

This study evaluates the safety and clinical utility of rotational angiography in the diagnosis of coronary artery disease. High-speed rotational angiography is a newly available angiographic modality that gives a dynamic multiple-angle perspective of the coronary tree during a single contrast injection. We prospectively randomized 56 patients referred for diagnostic coronary angiography to either standard or rotational angiography. Contrast and radiation utilization were compared between the two groups. The number of additional cine acquisitions needed was used to determine adequacy of the diagnostic study protocol. Rotational angiography was successfully completed in all subjects. There was a 33% reduction in contrast utilization in the rotational group as compared to the standard group (35.6 +/- 12.6 vs. 52.8 +/- 10.7 ml, respectively; P < 0.0001). Additionally, there was a 28% reduction in total radiation exposure in the rotational group as compared to the standard group (39.0 +/- 18.5 vs. 53.9 +/- 23.4 Gycm(2), respectively; P = 0.01). Total whole-body radiation exposure to the primary operator was 144 mrem with rotational angiography and 170 mrem with standard angiography. Procedure time tended to be shorter for rotational angiography (353.9 +/- 146.7 vs. 396.8 +/- 165.8 s; P = 0.3). Rotational coronary angiography can be rapidly performed in any patient and provides a significant reduction in contrast and radiation utilization while at the same time providing adequate angiographic data to complement or replace standard coronary angiography in the evaluation of coronary artery disease.

Adult↗

Initial clinical experience with intracardiac echocardiography in guiding balloon mitral valvuloplasty: technique, safety, utility, and limitations.

The objective of this study was to examine the feasibility and technique of intracardiac echocardiography during percutaneous balloon mitral valvuloplasty. Echocardiographic imaging is commonly used during mitral valvuloplasty. Intracardiac echocardiography is a newer technology that may provide superior imaging during complex valvular interventions. Intracardiac echocardiography and transthoracic echocardiography were performed in 19 patients undergoing percutaneous balloon mitral valvuloplasty. Intracardiac ultrasound images were obtained via the femoral vein in all patients. Imaging projections and catheter locations that were useful for the performance of mitral valvuloplasty were defined. Intracardiac echocardiography guided transseptal puncture, augmented the assessment of valve apparatus deformity, facilitated balloon positioning across the mitral valve, and permitted postprocedural valvular assessment including identification of mitral regurgitation with color Doppler. Intracardiac echocardiography provided essential imaging guidance and procedural monitoring during percutaneous mitral valvuloplasty.

Adult↗

Three-dimensional vascular angiography.

Traditional angiography of the vasculature is limited by its 2-dimensional projection of complex 3-dimensional structures and the consequent imaging artifacts that interfere with visualization. During the last 10 years, technologies capable of minimizing the shortcomings of traditional angiography have been developed and are now in clinical use. Rotational angiography and 3-dimensional imaging are 2 of these powerful tools and, together, represent a major advance in the angiographic diagnosis and treatment of patients with coronary, cerebral, and peripheral vascular disease.

Cardiovascular Diseases↗

Three-dimensional analysis of in vivo coronary stent--coronary artery interactions.

Stent implantation results in important three-dimensional (3D) changes in arterial geometry which may be associated with adverse events. Previous attempts to quantify these 3D changes have been limited by two-dimensional techniques. Using a 3D reconstruction technique, vessel curvatures at end-diastole (ED) and end-systole (ES) were measured before and after stent placement of 100 stents (3 stent cell designs, 6 stent types). After stenting, the mean curvature at ED and ES decreased by 22 and 21%, respectively, and represents a straightening effect on the treated vessel. This effect was proportional to the amount of baseline curvature as high vessel curvature predicted more profound vessel straightening. When analyzed by stent cell design, closed-cell stents resulted in more vessel straightening than other designs (open cell or modified slotted tubes). Stent implantation resulted in the transmission of shape changes to stent ends and generated hinge points or buckling. Stent implantation creates 3D changes in arterial geometry which can be quantified using a 3D reconstruction technique.

Blood Vessel Prosthesis Implantation↗

Impact of renal insufficiency in patients undergoing primary angioplasty for acute myocardial infarction.

BACKGROUND: The prognostic importance of renal insufficiency (RI) in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) has not been well characterized. METHODS AND RESULTS: PCI was performed in 2082 AMI patients without shock presenting within 12 hours of symptom onset in a prospective, multicenter randomized trial. RI was defined as a calculated (Cockroft-Gault) creatinine clearance (CrCl) < or =60 mL/min. RI at baseline was present in 18% of patients. Compared with patients without RI, patients with RI were older and were more likely to be female; to have hypertension, peripheral vascular disease, or cerebrovascular disease; and to present in heart failure. Mortality was markedly increased in patients with versus without baseline RI both at 30 days (7.5% versus 0.8%, P<0.0001) and at 1 year (12.7% versus 2.4%, P<0.0001). Mortality rates increased incrementally for every 10-mL/min decrease in baseline CrCl. By multivariate analysis, reduced baseline CrCl was a powerful independent predictor of 30-day mortality (hazard ratio, 5.77; P<0.0001) and remained associated with reduced survival at 1 year (hazard ratio, 1.98; P=0.08). Hemorrhagic complications and transfusion requirements were also increased more than 2-fold in patients with RI, as were severe restenosis (diameter stenosis > or =70%; 20.6% versus 11.8%, P=0.024) and infarct artery reocclusion (14.7% versus 7.3%, P=0.02). CONCLUSIONS: Baseline RI in patients with AMI undergoing primary PCI is associated with a markedly increased risk of mortality, as well as bleeding and restenosis. Novel approaches are needed to improve the otherwise poor prognosis of patients with RI and AMI.

Abciximab↗

Outcomes of bail-out stenting for suboptimal balloon angioplasty during primary intervention in acute myocardial infarction (The CADILLAC trial).

The results of bail-out stenting after unsuccessful primary balloon angioplasty compared with routine stenting or successful balloon angioplasty in acute myocardial infarction are unknown. In the CADILLAC trial, 168 of 1,044 patients (16.1%) randomized to balloon angioplasty crossed over to stenting after unsuccessful dilatation. Event-free survival was similar after bail-out and routine stenting, and was greater than after successful balloon angioplasty.

Aged↗

Feasibility and implications of an early discharge strategy after percutaneous intervention with abciximab in acute myocardial infarction (the CADILLAC Trial).

Early complications may hamper efforts to hasten discharge after primary percutaneous coronary intervention (PCI) for myocardial infarction (MI). Glycoprotein IIb/IIIa inhibitors, by reducing early recurrent ischemia, may aid in these efforts. We examined whether adjunctive abciximab could accelerate discharge and reduce costs within a trial of primary PCI after acute MI. The CADILLAC trial randomized 2,082 patients with MI to 1 of 4 reperfusion strategies in a 2 x 2 factorial design: angioplasty, angioplasty with abciximab, stent implantation, or stenting with abciximab. Patients randomized to abciximab had postprocedural heparin withheld, and discharge scheduled for days 1.5 to 2 (low-risk patients) or days 2 to 3 (high-risk patients) after MI if they were stable. Other patients were discharged at the physician's discretion. Abciximab treatment was associated with significant reductions in the primary end points of in-hospital death, reinfarction, ischemic target vessel revascularization (TVR), or disabling stroke (5.6% vs 2.7%, p = 0.003)--largely reflecting reduced ischemic TVR (3.8% vs 1.4%, p = 0.002)--and in early subacute thrombosis (1.3% vs 0.2%, p = 0.01). Hospitalization was significantly shorter in abciximab-treated patients (median 3.1 vs 3.5 days, p <0.001), but total in-hospital costs did not differ significantly (13,413 +/- 5,309 US dollars vs 13,000 +/- 6,006 US dollars, p = 0.13). Rates of the composite end point did not differ significantly during the week after discharge (0.8% vs 0.2%, p = 0.10), nor did component event rates. Abciximab during primary PCI is associated with fewer early adverse outcomes, likely contributing to offset its cost. Hospitalizations after primary PCI are so short, however, that efforts to accelerate discharge with abciximab appear unfeasible, and overall costs remain unchanged.

Abciximab↗

Intra-procedural coronary intervention planning using hybrid 3-dimensional reconstruction techniques.

RATIONALE AND OBJECTIVES: The purpose of this study was to develop a method to assist the cardiologist in planning an interventional procedure while the patient is on the catheterization table. MATERIALS AND METHODS: A rotational single plane x-ray system is used to acquire images while rapidly rotating the C-arm around the patient. Based on electrocardiogram-selected projections, both a volumetric cone-beam reconstruction of the coronary tree as well as a three-dimensional model of the vessel segment of interest is generated. This information is used to compute the appropriateness of a range of different viewing angles with respect to the overlap and foreshortening of the vessel segment of interest during the cardiac cycle which results in an interactive optimal view map. RESULTS: The proposed method has been tested on patient data and several phantom objects. The results show that both an accurate 3D model of a vessel segment of interest and its associated optimal view map can be generated to predict an appropriate gantry angle for subsequent image acquisition. CONCLUSION: The method provides an appropriate and feasible tool to assist interventional cardiologists in planning a coronary intervention while the patient is still on the catheterization table following diagnostic coronary angiography.

Cardiac Catheterization↗

Kinematic and deformation analysis of 4-D coronary arterial trees reconstructed from cine angiograms.

In the cardiovascular arena, percutaneous catheter-based interventional (i.e., therapeutic) procedures include a variety of coronary and other vascular system interventions. These procedures use two-dimensional (2-D) X-ray-based imaging as the sole or the major imaging modality for procedure guidance and quantification of key parameters. Coronary vascular curvilinearity is one key parameter that requires a four-dimensional (4-D) format, i.e., three-dimensional (3-D) anatomical representation that changes during the cardiac cycle. A new method has been developed for reconstruction and analysis of these patient-specific 4-D datasets utilizing routine cine angiograms. The proposed method consists of three major processes: 1) reconstruction of moving coronary arterial tree throughout the cardiac cycle; 2) establishment of temporal correspondence with smoothness constraints; and 3) kinematic and deformation analysis of the reconstructed 3-D moving coronary arterial trees throughout the cardiac cycle.

Algorithms↗

Stress analysis using anatomically realistic coronary tree.

Plaque rupture with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death. Endothelial disruption leading to plaque rupture may relate to mechanical fatigue associated with cyclic flexion of plaques. A novel method is proposed to assess stress and strain distribution using the finite element (FE) analysis and in vivo patient-specific dynamic 3D coronary arterial tree reconstruction from cine angiographic images. The local stresses were calculated on the diseased arterial wall which was modeled as consisting of a central fibrotic cap subjected to the cyclic flexion from cardiac contraction. Various parameters characterizing the plaque were chosen including vessel diameter, percentage narrowing, and lesion length. According to the FEA simulations, the results show that the smaller vessel diameter, greater percentage narrowing, and/or larger lesion size may result in higher stress on the plaque cap, with the vessel diameter as the dominant factor.

Arteries↗

Comparison of angioplasty with stenting, with or without abciximab, in acute myocardial infarction.

BACKGROUND: As compared with thrombolytic therapy, primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction reduces the rates of death, reinfarction, and stroke, but recurrent ischemia, restenosis, and reocclusion of the infarct-related artery remain problematic. When used in combination with PTCA, coronary stenting and platelet glycoprotein IIb/IIIa inhibitors may further improve outcomes. METHODS: Using a 2-by-2 factorial design, we randomly assigned 2082 patients with acute myocardial infarction to undergo PTCA alone (518 patients), PTCA plus abciximab therapy (528), stenting alone with the MultiLink stent (512), or stenting plus abciximab therapy (524). RESULTS: Normal flow was restored in the target vessel in 94.5 to 96.9 percent of patients and did not vary according to the reperfusion strategy. At six months, the primary end point - a composite of death, reinfarction, disabling stroke, and ischemia-driven revascularization of the target vessel - had occurred in 20.0 percent of patients after PTCA, 16.5 percent after PTCA plus abciximab, 11.5 percent after stenting, and 10.2 percent after stenting plus abciximab (P<0.001). There were no significant differences among the groups in the rates of death, stroke, or reinfarction; the difference in the incidence of the primary end point was due entirely to differences in the rates of target-vessel revascularization (ranging from 15.7 percent after PTCA to 5.2 percent after stenting plus abciximab, P<0.001). The rate of angiographically established restenosis was 40.8 percent after PTCA and 22.2 percent after stenting (P<0.001), and the respective rates of reocclusion of the infarcted-related artery were 11.3 percent and 5.7 percent (P=0.01), both independent of abciximab use. CONCLUSIONS: At experienced centers, stent implantation (with or without abciximab therapy) should be considered the routine reperfusion strategy.

Abciximab↗