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The Society for Cardiovascular Angiography and Interventions (SCAI) Think Tank is a collaborative venture that brings together interventional cardiologists, administrative partners, and select members of the cardiovascular industry community annually for high-level field-wide discussions. The 2021 Think Tank was organized into four parallel sessions reflective of the field of interventional cardiology: (a) coronary intervention, (b) endovascular medicine, (c) structural heart disease, and (d) congenital heart disease. Each session was moderated by a senior content expert and co-moderated by a member of SCAI's Emerging Leader Mentorship program. This document presents the proceedings to the wider cardiovascular community in order to enhance participation in this discussion, create additional dialog from a broader base, and thereby aid SCAI, the industry community and external stakeholders in developing specific action items to move these areas forward., (© 2021 Wiley Periodicals LLC.)

The Centers for Medicare & Medicaid Services (CMS) began reimbursement for percutaneous coronary intervention (PCI) performed in ambulatory surgical centers (ASC) in January 2020. The ability to perform PCI in an ASC has been made possible due to the outcomes data from observational studies and randomized controlled trials supporting same day discharge (SDD) after PCI. In appropriately selected patients for outpatient PCI, clinical outcomes for SDD or routine overnight observation are comparable without any difference in short-term or long-term adverse events. Furthermore, a potential for lower cost of care without a compromise in clinical outcomes exists. These studies provide the framework and justification for performing PCI in an ASC. The Society for Cardiovascular Angiography and Interventions (SCAI) supported this coverage decision provided the quality and safety standards for PCI in an ASC were equivalent to the hospital setting. The current position paper is written to provide guidance for starting a PCI program in an ASC with an emphasis on maintaining quality standards. Regulatory requirements and appropriate standards for the facility, staff and physicians are delineated. The consensus document identified appropriate patients for consideration of PCI in an ASC. The key components of an ongoing quality assurance program are defined and the ethical issues relevant to PCI in an ASC are reviewed., (© 2020 Wiley Periodicals LLC.)

The worldwide pandemic caused by the novel acute respiratory syndrome coronavirus 2 has resulted in a new and lethal disease termed coronavirus disease 2019 (COVID-19). Although there is an association between cardiovascular disease and COVID-19, the majority of patients who need cardiovascular care for the management of ischemic heart disease may not be infected with this novel coronavirus. The objective of this document is to provide recommendations for a systematic approach for the care of patients with an acute myocardial infarction (AMI) during the COVID-19 pandemic. There is a recognition of two major challenges in providing recommendations for AMI care in the COVID-19 era. Cardiovascular manifestations of COVID-19 are complex with patients presenting with AMI, myocarditis simulating an ST-elevation myocardial infarction (STEMI) presentation, stress cardiomyopathy, non-ischemic cardiomyopathy, coronary spasm, or nonspecific myocardial injury, and the prevalence of COVID-19 disease in the US population remains unknown with risk of asymptomatic spread. This document addresses the care of these patients focusing on (a) varied clinical presentations; (b) appropriate personal protection equipment (PPE) for health care workers; (c) the roles of the emergency department, emergency medical system, and the cardiac catheterization laboratory (CCL); and (4) regional STEMI systems of care. During the COVID-19 pandemic, primary percutaneous coronary intervention (PCI) remains the standard of care for STEMI patients at PCI-capable hospitals when it can be provided in a timely manner, with an expert team outfitted with PPE in a dedicated CCL room. A fibrinolysis-based strategy may be entertained at non-PCI-capable referral hospitals or in specific situations where primary PCI cannot be executed or is not deemed the best option., (© 2020 Wiley Periodicals, Inc.)

Evidence-based recommendations for clinical practice are intended to help health care providers and patients make decisions, minimize inappropriate practice variation, promote effective resource use, improve clinical outcomes, and direct future research. The Society for Cardiovascular Angiography and Interventions (SCAI) has been engaged in the creation and dissemination of clinical guidance documents since the 1990s. These documents are a cornerstone of the society's education, advocacy, and quality improvement initiatives. The publications committee is charged with oversight of SCAI's clinical documents program and has created this manual of standard operating procedures to ensure consistency, methodological rigor, and transparency in the development and endorsement of the society's documents. The manual is intended for use by the publications committee, document writing groups, external collaborators, SCAI representatives, peer reviewers, and anyone seeking information about the SCAI documents program., (© 2020 Wiley Periodicals, Inc.)

Objectives: To evaluate the safety of drug-eluting stents (DES) when treating patients with failing saphenous vein grafts (SVG)., Background: DES reduce target vessel revascularization in patients with failing SVGs; however, compared with bare metal stents (BMS), DES have been variably associated with increased mortality., Methods: Clinical records from National Cardiovascular Data Registry(®) CathPCI Registry(®) (49,325 older individuals [≥65 years] who underwent SVG stenting 2005-2009) were linked to Medicare claims to create a longitudinal record. Death, myocardial infarction (MI), and urgent revascularization with DES versus BMS were evaluated to 3 years using propensity matching (PM). Results were stratified by clinical presentation (acute coronary syndrome [ACS], non-ACS), previous lesion treatment (in-stent, de novo), and graft segment (aortic, body, distal anastomosis)., Results: In this older cohort (median age, 75 years), acute presentations were prevalent (ACS, 69%; TIMI flow <3, 45%), and adverse clinical outcomes were common by 3 years (death, 24.5%; MI, 14.6%; urgent revascularization, 29.5%). Among DES patients (n = 31,403), 3-year mortality was lower (vs. BMS) (22.7% vs. 28.0%, P < 0.001; PM hazard ratio [HR] 0.87, 95% confidence interval 0.83-0.91), and no difference was observed in the adjusted risk for MI (PM HR 0.97, 0.91 to 1.03) or urgent revascularization (PM HR 1.04, 0.99-1.08). These findings were independent of clinical presentation, previous lesion treatment, and graft segment (P interaction, ns)., Conclusions: In this large SVG PCI cohort, all-cause mortality was lower among those receiving DES, and no difference in MI or urgent revascularization was observed to 3 years. © 2015 Wiley Periodicals, Inc., (© 2015 Wiley Periodicals, Inc.)

Cardiogenic shock (CS) in the setting of acute myocardial infarction is associated with high in-hospital mortality rates. Society guidelines provide a Class Ib recommendation for the use of hemodynamic support devices in patients with CS following ST-elevation myocardial infarction. Exchanging of hemodynamic support devices is often complicated by inability to maintain percutaneous vascular access upon device removal in the setting of anticoagulation. This report highlights one potential solution to the dilemma of maintaining vascular access following removal of an Impella® 2.5 mechanical support device to allow safe transition to a TandemHeart system in a patient with refractory CS., (Copyright © 2013 Wiley Periodicals, Inc.)

Objective: We assessed the long-term outcomes of elderly patients who had in-stent restenosis (ISR) treated with drug-eluting stents (DES) compared with other treatment strategies., Background: Elderly patients with ISR represent a vulnerable group of which little is known regarding the safety and efficacy of repeat percutaneous coronary intervention (PCI)., Methods: We analyzed patients ≥ 65 years of age who underwent PCI for ISR in the National Cardiovascular Data Registry(®) from 2004 to 2008. Death, myocardial infarction (MI), revascularization, stroke, and bleeding were assessed for up to 30 months by a linkage with Medicare rehospitalization claims., Results: Of 43,679 linked patients, 30,012 were treated with DES, 8,277 with balloon angioplasty (BA), and 4,917 with bare metal stents (BMS). Compared with BMS, DES use was associated with a lower propensity score-matched (PM) risk of death (hazard ratio [HR] 0.72; 95% confidence interval [CI] 0.66-0.80, P < 0.001), MI (HR 0.81; 95% CI 0.70-0.93, P = 0.003), and revascularization (HR 0.90; 95% CI 0.82-1.00, P = 0.055). Compared with BA, DES use was associated with a lower PM risk of death (HR 0.82; 95% CI 0.76-0.89, P < 0.001) and revascularization (HR 0.86; 95% CI 0.80-0.93, P < 0.001), but no statistically significant difference across other endpoints. There were no significant differences in long-term outcomes for BA compared with BMS., Conclusions: There was lower mortality and reduced risk for MI, revascularization, and stroke, but a similar rate of bleeding with DES compared with other modalities. Our results indicate that DES use is a comparatively effective strategy to treat elderly patients with ISR., (Copyright © 2013 Wiley Periodicals, Inc.)

Objectives: To assess the current use and application of simulators in interventional cardiology., Background: Despite a paucity of data on the efficacy of simulation in medicine, cardiovascular simulation training is now a mandated part of cardiovascular fellowship training. Additionally, simulators have been endorsed by the Food and Drug Administration as a way to teach physicians new and novel procedures. We sought to establish the current use of simulators in cardiovascular medicine., Methods: A systematic review was done of available training programs, and currently existing data regarding simulation training. A panel of experts was convened to review this data and provide recommendations as how simulation should be used in the field of interventional cardiology., Results: This document provides a comprehensive review of the current state of simulation and how we as a society must formulate well validated studies to more closely examine and explore how this technology can be further studied and validated., Conclusions: Simulation will likely take on a larger role in cardiovascular training and maintenance of certification, but at the current time lacks a large body of evidence for its use., (Copyright © 2013 Wiley Periodicals, Inc.)

Objectives: We sought to examine the contemporary use of thrombectomy during primary percutaneous coronary intervention (PCI) in the United States., Background: Adjunctive thrombectomy during primary PCI for patients with ST-segment elevation myocardial infarction (STEMI) has demonstrated mixed results. While earlier studies showed either unfavorable or neutral effects with rheolytic thrombectomy, recent clinical trials have shown benefits with manual or rheolytic thrombectomy when compared to PCI alone., Methods: We analyzed data from 122,449 patients undergoing primary PCI for STEMI from 1,181 centers reported to the CathPCI Registry® between July 2009 and December 2010. We used logistic regression analysis to examine factors associated with the use of manual and rheolytic thrombectomy., Results: Thrombectomy was performed in 23,195 patients (18.9%): 22,404 (18.3%) had manual thrombectomy and 791 (0.6%) had rheolytic thrombectomy. The use of manual thrombectomy increased over time (P < 0.05). The use of rheolytic thrombectomy did not change. There was significant variation in the use of thrombectomy across hospitals. The strongest predictors of manual versus no thrombectomy included TIMI 0/1 flow (odds ratio 1.69), younger age (OR 0.90 per 10 year increase), saphenous vein graft (OR 2.22), glycoprotein IIb/IIIa inhibitor (OR 1.34), single-vessel disease (OR 1.13), and year of admission (OR 1.20 per year; all P < 0.001). The strongest predictor of manual versus rheolytic thrombectomy was year of admission (OR 1.23, P < 0.001)., Conclusions: Our data show that thrombectomy is performed infrequently in the US during primary PCI for STEMI. There is significant variation in the use of thrombectomy across US hospitals., (Copyright © 2012 Wiley Periodicals, Inc.)

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., (Copyright © 2011 Wiley-Liss, Inc.)

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., (Copyright 2009 Wiley-Liss, Inc.)

Background: This study sought to examine the impact of an aggressive approach to anatomic screening and endovascular revascularization in a veterans administration population with critical limb ischemia (CLI) on the primary treatments received and overall clinical outcomes., Methods: The baseline clinical and angiographic characteristics and clinical outcomes of the first consecutive fifty veterans who were referred for the evaluation and treatment of CLI using the strategy outlined were assessed by retrospective review of the computerized medical record and angiographic data., Results: Among the entire cohort, the primary treatments received were as follows--revascularization n = 44 (88%), primary amputation n = 1 (2%), medical treatment n = 3 (6%), and primary minor amputation n = 2 (4%). Endovascular revascularization was the dominant mode of revascularization (94%), with a procedural success rate of 91%. Repeat revascularization was required in 19% of patients who had an initially successful endovascular procedure. A total of eight deaths and four major amputations occurred in the entire cohort over a mean follow-up of 397 +/- 190 days. The 1-year Kaplan-Meier estimates for survival and amputation-free survival for the entire cohort were 90 and 81%, respectively. Resolution of rest pain or complete wound healing was achieved in 85% of patients at a mean of 157 +/-126 days., Conclusions: An aggressive approach to anatomic screening and contemporary endovascular treatment of CLI resulted in a higher rate of revascularization as the primary treatment for CLI than previously reported, and was associated with high rates of overall and amputation-free survival., (Copyright 2009 Wiley-Liss, Inc.)

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.

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., (Copyright (c) 2007 Wiley-Liss, Inc.)

The development of acute limb ischemia in patients following intra-aortic balloon pump (IABP) placement remains a frequent event that presents a significant management challenge. We report two recent cases of this clinical event from our institution, which demonstrate that endovascular therapies may be used to treat acute limb ischemia in this setting without requiring removal of the IABP., ((c) 2007 Wiley-Liss, Inc.)

New onset of acute lower extremity ischemia following percutaneous coronary and cardiac interventional procedures using femoral access is an important clinical entity that requires emergent assessment to determine the precise etiology and institute appropriate therapy. We report four cases of this clinical event from our catheterization laboratories that serve to highlight the most frequent etiologies, the importance of immediate diagnostic angiography, and the potential for endovascular techniques to effectively manage this complication., ((c) 2007 Wiley-Liss, Inc.)

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., (Copyright 2005 Wiley-Liss, Inc.)

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., (Copyright 2004 Wiley-Liss, Inc.)

Third-generation intracoronary stents allow deployment at higher pressures, possibly obviating the need for high-pressure postdilations and also possibly reducing restenosis. This study evaluated the ability of the Tristar Coronary Stent System to produce optimal stent deployment as measured by intravascular ultrasound (IVUS) and quantitative coronary angiography in 46 patients. Optimal stent deployment was defined as minimal luminal area > 80% of the average of the proximal and distal reference luminal areas. After initial deployment, 74.5% of stents met criteria for optimal stent deployment by IVUS, with an average stent expansion ratio of 89.6%. Ten stents (18.2%) were postdilated. Four patients (8.7%) had a major adverse cardiac event, one patient died, one patient had a myocardial infarction, and two patients had target vessel revascularization at 6 months. The Tristar stent system produces optimal deployment without the need for routine postdilation and results in optimal clinical outcomes., (Copyright 2002 Wiley-Liss, Inc.)

The objective of this study was to derive a method for quantifying the dynamic geometry of coronary arteries. Coronary artery geometry plays an important role in atherosclerosis. Coronary artery geometry also influences the performance of coronary interventions. Conversely, implantation of stents may alter coronary artery geometry. Clinical tools to define vessel shape have not been readily available. Using a Frenet-Serret curvature analysis applied to 3D reconstruction data derived from standard coronary angiograms, 21 coronary arteries were analyzed at end-diastole (ED) and end-systole (ES). Vessels were divided anatomically: type 1 consisted of vessels lying in the AV groove (left circumflex, right coronary) and type 2 consisted of vessels overlying actively contracting myocardium (left anterior descending, diagonal, obtuse marginal, right ventricular marginal, posterior descending, posterolateral). Vessel segments were analyzed by assessing the changes in curvature, torsion, and discrete flexion points (FPs), areas of systolic bending in the arterial contour. The curvature from ED to ES of type 1 vessels was unchanged (-0.02 +/- 0.03 cm(-1)), while the curvature change of type 2 vessels showed a 38% increase (0.33 +/- 0.04 cm(-1); P < 0.001). Type 1 vessels had fewer FPs per vessel than type 2 vessels (0.38 +/- 0.18 and 2.40 +/- 0.23 FP/vessel, respectively; P < 0.001). FPs were more common in distal segments and branch vessels. A method to quantify cyclic changes in coronary artery shape was applied to 3D data sets derived from standard coronary angiograms. Coronary arteries undergo a cyclic change in shape resulting in changes in overall curvature as well as formation of discrete flexion points. These changes in vessel shape are asymmetrically distributed in coronary arteries., (Copyright 2002 Wiley-Liss, Inc.)