Safety and efficacy of dual-axis rotational coronary angiography vs. standard coronary angiography.

OBJECTIVE: To determine the safety and efficacy of dual-axis rotational coronary angiography (DARCA) by directly comparing it to standard coronary angiography (SA). BACKGROUND: Standard coronary angiography (SA) requires numerous fixed static images of the coronary tree and has multiple well-documented limitations. Dual-axis rotational coronary angiography (DARCA) is a new rotational acquisition technique that entails simultaneous LAO/RAO and cranial/caudal gantry movement. This technological advancement obtains numerous unique images of the left or right coronary tree with a single coronary injection. We sought to assess the safety and efficacy of DARCA as well as determine DARCA's adequacy for CAD screening and assessment. METHODS: Thirty patients underwent SA following by DARCA. Contrast volume, radiation dose (DAP) and procedural time were recorded for each method to assess safety. For DARCA acquisitions, blood pressure (BP), heart rate (HR), symptoms and any arrhythmias were recorded. All angiograms were reviewed for CAD screening adequacy by two independent invasive cardiologists. RESULTS: Compared to SA, use of DARCA was associated with a 51% reduction in contrast, 35% less radiation exposure, and 18% shorter procedural time. Both independent reviewers noted DARCA to be at least equivalent to SA with respect to the ability to screen for CAD. CONCLUSION: DARCA represents a new angiographic technique which is equivalent in terms of image quality and is associated with less contrast use, radiation exposure, and procedural time than SA.

Rapid prototyping: a new tool in understanding and treating structural heart disease.

As the appreciation of structural heart disease in children and adults has increased and as catheter-based closure procedures are now being performed in clinical practice, cardiovascular physicians have multiple compelling new reasons to better understand cardiac anatomic and spatial relationships. Current 2-dimensional imaging techniques remain limited both in their ability to represent the complex 3-dimensional relationships present in structural heart disease and in their capacity to adequately facilitate often complex corrective procedures. This review discusses the cardiovascular applications of rapid prototyping, a new technology that may not only play a significant role in the planning of catheter-based interventions but also may serve as a valuable educational tool to enhance the medical community's understanding of the many forms of structural heart disease.

Quantitative assessment of the conformational change in the femoropopliteal artery with leg movement.

BACKGROUND: The unique physical forces exerted on the femoropopliteal (FP) artery during movement have been implicated in the high rates of restenosis and stent fracture in this artery. Conformational changes in the FP artery during movement are important surrogates of these forces. This study sought to quantify the conformational change in the FP artery between the straight-leg (SL) and crossed-leg (CL) positions. METHODS: Using paired angiographic images of overlapping segments of the FP artery in SL and CL positions from patients with peripheral arterial disease, 3-D models of individual segments were generated and subsequently fused to create a 3-D model of the entire FP artery in both leg positions. Based on these 3-D models, the following parameters in the SL and CL positions were quantitatively assessed for the superficial femoral artery (SFA), popliteal artery (PA), and FP artery (i.e., SFA and PA): length, curvature, torsion, twist angle, and development of new flexion angles = 15 degrees. RESULTS: In nine male patients with a mean age of 57 +/- 10.2 years, angiography was performed in 10 FP arteries, with successful generation of 3-D models for all vessels. Movement from the SL to the CL position for the SFA, PA, and FP artery was associated with (a) a mean shortening of 18.2 mm (P = 0.002), 32.2 mm (P < 0.001), and 50.3 mm (P < 0.001), respectively; (b) a mean increase in curvature of 0.04 cm(-1) (P = 0.012), 0.2 cm(-1) (P < 0.001), and 0.11 cm(-1) (P < 0.001), respectively; (c) and small absolute changes in mean torsion of 0.034 cm(-1) (P = 0.48), 0.006 cm(-1) (P < 0.001), and 0.057 cm(-1) (P < 0.001), respectively. The same leg movement was associated with a mean twist angle of 45.6 degrees +/- 27.9 degrees (range of 17.4 degrees-103.4 degrees ) and 61.1 degrees +/- 31.9 degrees (range of 20.5 degrees-101.1 degrees ) for the SFA and PA, respectively. Compared to the SL position, the CL position induced a single flexion point (FxP) =15 degrees in the SFA in two patients, and a mean of 2.4 FxPs =15 degrees (range 1-5) in the PA. CONCLUSIONS: Significant changes in length, curvature, and twist occur in the PA and significant but more modest changes in length and twist occur in the SFA during movement from the SL to the CL position. This data has important implications for endovascular therapies that are used to treat disease in the FP artery.

Rotational vs. standard coronary angiography: an image content analysis.

OBJECTIVE: To evaluate the clinical utility of images acquired from rotational coronary angiographic (RA) acquisitions compared to standard "fixed" coronary angiography (SA). BACKGROUND: RA is a novel angiographic modality that has been enabled by new gantry systems that allow calibrated automatic angiographic rotations and has been shown to reduce radiation and contrast exposure compared to SA. RA provides a dynamic multiple-angle perspective of the coronaries during a single contrast injection. METHODS: The screening adequacy, lesion assessment, and a quantitative coronary analysis (QCA) of both SA and RA were compared by independent blinded review in 100 patients with coronary artery disease (CAD). RESULTS: SA and RA recognize a similar total number of lesions (P = 0.61). The qualitative assessment of lesion characteristics and severity between modalities was comparable and lead to similar clinical decisions. Visualization of several vessel segments (diagonal, distal RCA, postero-lateral branches and posterior-descending) was superior with RA when compared to SA (P < 0.05). A QCA comparison (MLD, MLA, LL, % DS) revealed no difference between SA and RA. The volume of contrast (23.5 +/- 3.1 mL vs. 39.4 +/- 4.1; P = 0.0001), total radiation exposure (27.1 +/- 4 vs. 32.1 +/- 3.8 Gycm(2); P = 0.002) and image acquisition time (54.3 +/- 36.8 vs. 77.67 +/- 49.64 sec; P = 0.003) all favored RA. CONCLUSION: Coronary lesion assessment, coronary screening adequacy, and QCA evaluations are comparable in SA and RA acquisition modalities in the diagnosis of CAD however RA decreases contrast volume, image acquisition time, and radiation exposure.

Enhanced stent visualization: a case series demonstrating practical applications during PCI.

BACKGROUND: Visualization of coronary stents is increasingly challenging due to the reduction in stent strut thickness to improve deliverability. On the other hand stent expansion and precise implantation in the target vessel are important in optimizing short and long-term outcomes of stent-based revascularization. Stentboost Subtract is a novel X-ray technique that improves visualization of deployed stents in the coronary arteries. Using motion compensation and integration of multiple non-contrast projection images from a fixed gantry position, this new technique depicts stent morphology allowing assessment of stent expansion and extent of overlap with adjacent stents. We present a case series in which enhanced stent visualization (ESV) facilitated interventions. METHODS: The clinical and angiographic characteristics of 6 cases utilizing ESV were reviewed. All ESV acquisitions in this case series utilized an 8 in. field of view (FOV), 3 ml/sec. for a total of 6 ml of contrast, and placement of balloon markers in the region of interest. RESULTS: The cases presented significantly facilitated the identification of bifurcation stenting techniques, precise stent positioning, stent underexpansion and assisted with defining stent-vessel wall relationship that was additive to intravascular ultrasound. CONCLUSIONS: ESV is a novel tool used in coronary interventions that facilitates non-invasive assessment of stent positioning, expansion and stent-vessel interactions. This inexpensive ESV technique is complimentary to IVUS and in some cases obviates its need.

The future cardiac catheterization laboratory.

This article describes the major components in the future cardiac catheterization laboratory to facilitate cardiac interventions for both coronary artery and structural heart diseases.

Determination of optimal viewing regions for X-ray coronary angiography based on a quantitative analysis of 3D reconstructed models.

Current expert-recommended views for coronary angiography are based on heuristic experience and have not been scientifically studied. We sought to identify optimal viewing regions for first and second order vessel segments of the coronary arteries that provide optimal diagnostic value in terms of minimizing vessel foreshortening and overlap. Using orthogonal 2D images of the coronary tree, 3D models were created from which patient-specific optimal view maps (OVM) allowing quantitative assessment of vessel foreshortening and overlap were generated. Using a novel methodology that averages 3D-based optimal projection geometries, a universal OVM was created for each individual coronary vessel segment that minimized both vessel foreshortening and overlap. A universal OVM model for each coronary segment was generated based on data from 137 patients undergoing coronary angiography. We identified viewing regions for each vessel segment achieving a mean vessel foreshortening value of 5.8 +/- 3.9% for the left coronary artery (LCA) and 5.6 +/- 3.6% for the right coronary artery (RCA). The overall mean overlap values achieved were 8.7 +/- 7.9% for the LCA and 4.6 +/- 3.2% for the RCA. This scientifically-based OVM evaluation of coronary vessel segments provides the means to facilitate acquisitions during coronary angiography and interventions that minimize imaging inaccuracies related to foreshortening and overlap, improving the accuracy, efficiency, and safety of diagnostic and interventional coronary procedures.

Use of rapid prototyping in the care of patients with structural heart disease.

Advances in surgery, interventional techniques, and critical care have allowed more than 90% of children born with structural heart defects to survive into adulthood. In addition, advances in imaging technology continue to raise awareness of hemodynamically significant intracardiac shunt lesions in both adults and children. Adult cardiologists are now faced with the daunting task of caring for patients with complex structural heart lesions, a population subset that at one time was exclusively cared for by pediatric cardiologists and congenital heart disease specialists. Given the wide range of anatomic complexity present in patients with structural heart disease, the definition and anatomic clarification of their structural abnormalities through high-quality noninvasive imaging has become paramount. Current two-dimensional imaging techniques, however, remain limited in their ability to effectively illustrate the complex three-dimensional relationships present in structural heart disease. Rapid prototyping, a process by which three-dimensional digital surface models are converted into physical models, represents the next evolution in advanced image processing and may serve as a means to improve our understanding of the many forms of structural heart disease. Ultimately, the technology may be used to enhance the level of care provided to the growing number of patients with structural heart defects. We recently reviewed the novel cardiovascular application of rapid prototyping. This review examines the expanded applications of rapid prototyping in the care and treatment of adult patients with structural heart disease.

Rotational angiography (RA) and three-dimensional imaging (3-DRA): an available clinical tool.

Being able to accurately choose an optimal view for stent positioning, non foreshortened length and to avoid side branches is imperative during therapeutic procedures. Traditional imaging limitations may include the selection of an incorrectly sized stent, inaccurate placement, and/or the need for additional stents. With the use of newer acquisition techniques and three-dimensional (3-D) modeling/reconstructions this can be minimized. We present a case in which with the assistance of 3-D and its computer derived optimal view, and optimal length, a significant amount of vessel foreshortening was eliminated therefore improving the procedural outcome.

Percutaneous closure of a para-prosthetic aorto-right ventricular fistula.

A 60-year-old woman with increasing dyspnea was found to have a para-prosthetic aorto-right ventricular fistula during post-operative evaluation. Due to her multiple sternotomies, she was considered to be high risk for open surgical repair and referred for percutaneous intervention. A 6/4 mm Amplatzer occluder device (AGA Medical, Golden Valley, MN) was successfully delivered across the fistula with excellent immediate angiographic results.

Initial clinical experience of selective coronary angiography using one prolonged injection and a 180 degrees rotational trajectory.

OBJECTIVE: Evaluate the safety of prolonged coronary injections during a rotational acquisition covering 180 degrees. BACKGROUND: Rotational angiography has been adapted to coronary angiography and shown to reduce radiation and contrast exposure. Three-dimensional (3D) reconstructions and other advanced applications require imaging over a 180 degrees -arc with a single but longer injection of larger contrast volumes. METHODS: Thirty patients referred for angiography were enrolled. Blood pressure (BP), heart rate (HR), symptoms, and ectopy were recorded before-and-after injections. RESULTS: Pre and post-injection HRs for the LCA/RCA were not statistically different (LCA-pre-injection 63+/-13 bpm vs. LCA-post-injection 62+/-11 bpm, P=0.54 and RCA-pre-injection 65+/-12 bpm vs. RCA-post-injection 65+/-10, P=0.88). Central aortic pressure values were not statistically different for the RCA injections (RCA-systolic-pre-injection 118+/-14 mm Hg vs. RCA-systolic-post-injection 112+/-25 mm Hg, P=0.15, and RCA diastolic-pre-injection 69+/-9 mm Hg vs. RCA-diastolic-post-injection 60+/-10 mm Hg, P=0.88) but were statistically significant for the LCA injections (LCA systolic-pre-injection 122+/-19 mm Hg vs. LCA-systolic-post-injection 116+/-17 mm Hg, P=0.0004, and LCA-diastolic-pre-injection 69+/-10 mm Hg vs. LCA-diastolic-post-injection 65+/-9 mm Hg, P=0.0007). There were no symptoms or electrical events documented during or immediately post-injection. CONCLUSION: This study demonstrates the feasibility and safety of longer coronary injections. There were no significant HR changes, clinically insignificant pressure changes, and no adverse reactions. Additional studies will be needed to assure its safety in a larger and clinically more varied patient population.

Simultaneous multivessel acute drug-eluting stent thrombosis.

Stent thrombosis (ST) in the era of bare metal stents (BMS) using high-pressure stent deployment and combined anti-platelet therapy is an uncommon but feared complication. There is concern for an elevated risk of stent thrombosis (ST) with drug-eluting stents (DES). We describe a case of simultaneous multivessel drug-eluting stent thrombosis 8 h after deployment of paclitaxel-eluting stents in the right coronary (RCA) and left anterior descending (LAD) arteries.

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.

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.

Dynamic three-dimensional reconstruction and modeling of cardiovascular anatomy in children with congenital heart disease using biplane angiography.

Modeling and simulation of cardiovascular biomechanics and fluid dynamics from patient-specific data is a continuing topic of research investigation. Several methodologies utilizing CT, MRI and ultrasound to re-create the three-dimensional anatomy of the cardiovascular system have been examined. Adaptation of these models to pediatric applications has not been studied as extensively. There is significant need for such techniques in pediatric congenital heart disease since local anatomy may exhibit highly unusual geometry, and three-dimensional information would be of significant use for surgical and interventional planning, biomechanical and fluid dynamic simulation, and patient counseling. We report here on the adaptation and application of a three-dimensional reconstruction technique that utilizes bi-plane angiographic images as the base data sets. The method has been validated in a variety of adult imaging situations including coronary artery imaging and intervention. The method uses a skeletonization approach whereby local centerline, diameter, branching and tortuosity of the vasculature are obtained to create the three-dimensional model. Ten patients with a variety of etiology were imaged and 3D reconstructions were obtained. Excellent images were obtained of complex anatomy including the highly branched pulmonary vasculature and Fontan surgical connections. The data were then translated into solid and surface models to facilitate viewing, export into computational fluid dynamic grids, and into files suitable for stereo lithography fabrication (STL). This method appears promising for the dynamic study of complex cardiovascular anatomy found in congenital heart disease. Optimization of the method to facilitate on-line reconstruction and simulation are currently ongoing.

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.