Coronary venous imaging with electron beam computed tomographic angiography: three-dimensional mapping and relationship with coronary arteries

Evaluation of the anatomical variations of the coronary venous system in patients with coronary artery calcification using 256-slice computed tomography

The factors that determine the anatomical variations of the coronary venous system (CVS) are poorly understood. The objective of this study was to evaluate the anatomical variations of the CVS in patients with coronary artery calcification. 196 patients underwent non-contrast CT and coronary CT angiography using 256-slice CT. All subjects were divided into four groups based on their coronary artery calcium score (CACS): 50 patients with CACS = 0 Agatston unit (AU), 52 patients with CACS = 1–100 AU, 44 patients with CACS = 101–400 AU, and 50 patients with CACS > 400 AU. The presence of the following cardiac veins was evaluated: the coronary sinus (CS), great cardiac vein (GCV), posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV), left marginal vein (LMV), anterior interventricular vein (AIV), and small cardiac vein (SCV). Vessel diameters were also measured. We found that the CS, GCV, PIV, and AIV were visualized in all patients, whereas the PVLV and LMV were identified in a certain proportion of patients: 98% and 96% in the CACS = 0 AU group, 100% and 78.8% in the CACS = 1–100 AU group, 93.2% and 77.3% in the CACS = 101–400 AU group, and 98% and 78% in the CACS > 400 AU group, respectively. The LMV was less often identified in the last three groups than in the first group (p < 0.05). The frequency of having either one PVLV or LMV was higher in the last three groups than in the first group (p < 0.05). No significant differences in vessel diameters were observed between the groups. It was concluded that patients with coronary artery calcification were less likely to have the LMV, which might hamper the left ventricular lead implantation in cardiac resynchronization therapy.

Association of Difference in Coronary Sinus Diameter by Computed Tomographic Angiography Between Patients in and Not in Stable Atherosclerotic Plaque(S)

Background

Pathological finding fail to describe the morphology of coronary arterial plaques. Retrograde cardiac arteriography is a complicated procedure and does not detect all left posterior and marginal veins of the heart. Magnetic resonance angiography has long scan time and low spatial resolution. The objective of the present study was to assess the possible utility of the difference in coronary sinus diameter to quantify stable atherosclerotic plaque(s) using 256-slice coronary computed tomographic angiography.

Material/Methods

A total of 336 patients were divided into 2 groups with 168 patients each. Patients who had heart failure were included in the study group and those who did not were included in the non-study group. Patients were subjected to cross-sectional study. Cardiovascular images were performed with 256-slice coronary computed tomographic angiography with a prospective electrocardiogram and clinical manifestation. Two-tailed paired t test following Dunnett’s multiple comparison tests was performed for the quantitative measurement of coronary computed tomographic angiography and clinical manifestation at 99% confidence level.

Results

The clinical manifestation did not clearly show cardiac abnormality. The diameters of the superoinferior coronary sinus ostium was than that of the anteroposterior coronary sinus ostium, (p<0.0001, q=26.325). There was the difference in size of the coronary sinus ostium between patients in and not in heart failure (p<0.0001). The study group patients had longer coronary sinuses than patients in the non-study group (p<0.0001).

Conclusions

256-slice computed tomographic angiography is a feasible and is non-invasive bio-tool for evaluation of coronary artery anatomy.

Virtual medicine: Utilization of the advanced cardiac imaging patient avatar for procedural planning and facilitation

Advances in imaging technology have led to a paradigm shift from planning of cardiovascular procedures and surgeries requiring the actual patient in a "brick and mortar" hospital to utilization of the digitalized patient in the virtual hospital. Cardiovascular computed tomographic angiography (CCTA) and cardiovascular magnetic resonance (CMR) digitalized 3-D patient representation of individual patient anatomy and physiology serves as an avatar allowing for virtual delineation of the most optimal approaches to cardiovascular procedures and surgeries prior to actual hospitalization. Pre-hospitalization reconstruction and analysis of anatomy and pathophysiology previously only accessible during the actual procedure could potentially limit the intrinsic risks related to time in the operating room, cardiac procedural laboratory and overall hospital environment. Although applications are specific to areas of cardiovascular specialty focus, there are unifying themes related to the utilization of technologies. The virtual patient avatar computer can also be used for procedural planning, computational modeling of anatomy, simulation of predicted therapeutic result, printing of 3-D models, and augmentation of real time procedural performance. Examples of the above techniques are at various stages of development for application to the spectrum of cardiovascular disease processes, including percutaneous, surgical and hybrid minimally invasive interventions. A multidisciplinary approach within medicine and engineering is necessary for creation of robust algorithms for maximal utilization of the virtual patient avatar in the digital medical center. Utilization of the virtual advanced cardiac imaging patient avatar will play an important role in the virtual health care system. Although there has been a rapid proliferation of early data, advanced imaging applications require further assessment and validation of accuracy, reproducibility, standardization, safety, efficacy, quality, cost effectiveness, and overall value to medical care.

The Thebesian valve height/coronary sinus ostium diameter ratio (H/D-Ratio) as a new indicator for specifying the morphological shape of the valve itself in multisliced computed tomography

BACKGROUND

The coronary sinus ostium (CSO) is covered by the Thebesian valve (ThebV), which has a variable shape when assessed subjectively. The ThebV is an anatomical barrier during CS cannulation, which may be complicated due to the valves' size. The types of valves are: cord, remnant, semilunar, fold, and mesh/fenestrated. The ThebV can be visible using multisliced computed tomography (MSCT), however, this method cannot show the ThebV's morphological shape, only its size.

METHODS

301 randomly selected autopsied human hearts were examined. The shape of the valve was subjectively assessed, whereas the ThebV height (H) and the CSO diameter (D) were measured. The H/D-Ratio was computed as the ThebV height divided by the CSO diameter, afterwards k-means cluster analysis was performed to estimate H/D-Ratio's range of values between valves. MSCT scans from 114 patients that underwent CSO cannulation were objectively evaluated based on similar measured parameters in accordance with received H/D-Ratio values.

RESULTS

Boundaries of ratio evaluations between remnant and semilunar, and semilunar and fold types were 0.35 and 0.65 respectively. In MSCT scans, the ThebV was recorded in 61 cases (remnant=5.3%, semilunar=24.6%, fold=16.7%, cord=0.0%, mesh/fenestrated=7.9%). Except for the remnant and cord types, the other types appear similarly as in the cadaveric and MSCT studies. There were no differences between ThebV height and the CSO diameter in cadavers and MSCT studies.

CONCLUSION

The H/D-Ratio can be useful in assessing ThebV shape as visualized in MSCT. We give threshold values for the H/D-Ratio which easily allow the ThebV shape to be determined.

Planning and guidance of cardiac resynchronization therapy-lead implantation by evaluating coronary venous anatomy assessed with multidetector computed tomography

OBJECTIVES

We sought to evaluate the utility of multidetector computed tomography (MDCT) in preoperative planning of cardiac resynchronization therapy (CRT) device implantation.

BACKGROUND

Variation in coronary venous anatomy can affect optimal lead placement and may warrant preimplantation visualization prior to CRT lead placement.

METHODS

Prospective randomized enrollment of 29 patients (17 males; mean age at implant 66.7 ± 12.8 years) was undertaken. Patients were randomized to preimplantation MDCT (GE^® 64-detector Lightspeed, n = 16) or no MDCT. Implantation was planned based on three-dimensional coronary venous reconstruction as visualized in the CT group. Measurement of coronary sinus (CS) angulation, CS ostial (os) diameter, right atrial (RA) width, volume, and height was undertaken prior to implant. Intraoperative CS lead implantation times (introduction, cannulation, and left ventricular [LV] lead positioning), procedure time, fluoroscopy time, and venogram contrast volume were measured to determine if there was a difference between patients who underwent preimplant CT scan and those who did not.

RESULTS

CS os diameter (mean = 13.8 ± 2.9 cm) was inversely correlated with total fluoroscopy time (r = −0.57, P = .008), and total procedure time, but this correlation was not statistically significant (r = −0.36, P = 0.12). RA width (mean = 52.8 ± 9.9 cm) was associated with a shorter total procedure time (r = −0.44, P = .047) and LV lead positioning time (r = −0.33, P = .012). There were no statistically significant differences between the CT group and the non-CT group with respect to total intraoperative and fluoroscopy times or venogram contrast volumes. Total procedure time was longer in the CT group but the difference was not statistically significant (94 ± 27.2 vs. 74.7 ± 26.6; P = .065).

CONCLUSION

Noninvasive visualization of the coronary venous anatomy before CRT implantation can be used as a guide for lead placement. While no significant differences were noted between the two groups with respect to intraoperative variables, CS os diameter and RA width inversely correlated to a shorter procedure time and LV lead positioning time, respectively. Further clinical trials regarding the utility of MDCT to visualize coronary venous anatomy prior to CRT implantation for procedural planning and lead placement guidance are warranted.

Optimization of free-breathing whole-heart 3-dimensional cardiac magnetic resonance imaging at 3 tesla to identify coronary vein anatomy and to compare with multidetector computed tomography

OBJECTIVE

This study optimizes use of 3-T magnetic resonance imaging (MRI) to delineate coronary venous anatomy and compares 3-T MRI with multidetector computed tomography (MDCT) measurements.

METHODS

The study population included 37 consecutive subjects (22 men, 19-71 years old). Whole-heart contrast-enhanced MRI images at 3 T were acquired using segmented k-space gradient echo with inversion recovery prepared technique. The MDCT images were obtained using nonionic iodinated contrast.

RESULTS

The coronary sinus and great cardiac, posterior interventricular, and anterior interventricular veins were visualized in 100% of cases by both MRI and MDCT. Detection of the posterior vein of the left ventricle and the left marginal vein by MRI was 97% and 81%, respectively. Bland-Altman plots showed agreement in ostial diameter measured by both modalities with correlation coefficients ranging from 0.5 to 0.76. Vein length and distances also agreed closely.

CONCLUSIONS

Free-breathing whole-heart 3-dimensional MRI at 3 T provides high-spatial-resolution images and could offer an alternative imaging technique instead of MDCT scans.

Assessment of the coronary venous system using 256-slice computed tomography

Purpose

To investigate the coronary venous system and its relation to adjacent structures using 256-slice computed tomography (CT).

Materials and Methods

The study consisted of 102 patients who underwent coronary CT angiography (CTA) using 256-slice CT. For each patient, the coronary venous system and its relation to adjacent structures were evaluated. The appropriate locations and diameters of the posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV) and the left marginal vein (LMV) were detected. The paired student's t test was used to evaluate the difference between the diameter of the coronary sinus (CS) ostium in anteroposterior direction and that in superoinferior direction.

Results

The CS, great cardiac vein (GCV), PIV, and anterior interventricular vein (AIV) were visualized in all cases. It was possible to evaluate at least one main vein with adequate caliber and regular course for cardiac resynchronization therapy (CRT) in 96.1% of these cases. The diameter of the CS ostium in superoinferior direction (11.7±2.1 mm) was larger than that in anteroposterior direction (9.0±2.0 mm) (t = 13.511, P<0.05). For the majority of the cases, the CS-GCV was located above the level of the mitral valve annulus (MVA), while the left circumflex coronary artery (LCX) was coursed between the CS-GCV and the MVA. LMV had more intersection with the circumflex or circumflex marginal than PVLV.

Conclusion

256-slice CT provides superior noninvasive evaluation of the coronary venous system which has important clinical implications.

Anatomical reconstructions of the human cardiac venous system using contrast-computed tomography of perfusion-fixed specimens

A detailed understanding of the complexity and relative variability within the human cardiac venous system is crucial for the development of cardiac devices that require access to these vessels. For example, cardiac venous anatomy is known to be one of the key limitations for the proper delivery of cardiac resynchronization therapy (CRT)(1) Therefore, the development of a database of anatomical parameters for human cardiac venous systems can aid in the design of CRT delivery devices to overcome such a limitation. In this research project, the anatomical parameters were obtained from 3D reconstructions of the venous system using contrast-computed tomography (CT) imaging and modeling software (Materialise, Leuven, Belgium). The following parameters were assessed for each vein: arc length, tortuousity, branching angle, distance to the coronary sinus ostium, and vessel diameter. CRT is a potential treatment for patients with electromechanical dyssynchrony. Approximately 10-20% of heart failure patients may benefit from CRT(2). Electromechanical dyssynchrony implies that parts of the myocardium activate and contract earlier or later than the normal conduction pathway of the heart. In CRT, dyssynchronous areas of the myocardium are treated with electrical stimulation. CRT pacing typically involves pacing leads that stimulate the right atrium (RA), right ventricle (RV), and left ventricle (LV) to produce more resynchronized rhythms. The LV lead is typically implanted within a cardiac vein, with the aim to overlay it within the site of latest myocardial activation. We believe that the models obtained and the analyses thereof will promote the anatomical education for patients, students, clinicians, and medical device designers. The methodologies employed here can also be utilized to study other anatomical features of our human heart specimens, such as the coronary arteries. To further encourage the educational value of this research, we have shared the venous models on our free access website: www.vhlab.umn.edu/atlas.

Novel tips for engaging the coronary sinus guided by right ventricular lead

AIMS

This study investigated the relationship between the ostia of the coronary sinus (CS) and the tricuspid annulus (TA) for CS cannulation using a right ventricular (RV) lead, which could map out the TA by forming a curve when placed at the apex or low septum.

METHODS AND RESULTS

Seventy patients (45 males, 67 ± 12 years) who were admitted for CRT device implant were included in the evaluation of the relationship between the CS ostia and TA. An electrophysiological (EP) mapping catheter was used to probe the CS. The ostium was shown by the CS venography at the left anterior oblique (LAO) 20° and caudal 20°. Local electrograms were collected with CS catheters in the CS or RV. Transthoracic echocardiography was evaluated before each procedure. All CS ostia were located within 3.75 cm around the tip of TA. Sixty-two subjects (Group I, 89%) had CS ostia located under the TA. Eight patients (Group II) with CS ostia over the TA revealed larger left ventricular (LV) size and a smaller ratio of left atrium (LA)/LV size. LV enlargement predicted the presence of CS ostia over the TA. Typical CS electrograms were used to further confirm if the EP catheter was in the CS in all the subjects.

CONCLUSION

Use of the RV lead revealed that the CS ostia had a close relationship with the TA.

Cardiac resynchronization therapy: double cannulation approach to coronary venous lead placement via a prominent thebesian valve

We report identification of a prominent Thebesian valve by cardiovascular computed tomography (CT) angiography impeding cannulation of the coronary sinus, with subsequent successful coronary venous lead placement with cannulation of the coronary sinus ostium via a transvenous femoral vein approach and subsequent cannulation of the ostium with the coronary venous lead with a left subclavian approach. A 57-year-old man with nonischemic dilated cardiomyopathy, New York Heart Association Class III heart failure, left bundle branch block, and an ejection fraction of 15%, underwent an attempted cardiac resynchronization therapy implantable cardiac defibrillator (ICD). As the coronary sinus ostium could not be cannulated, a dual chamber ICD was placed. The patient subsequently underwent cardiovascular CT angiography, which identified a prominent Thebesian valve at the coronary sinus ostium as the anatomic obstacle to cannulation. Reattempted transvenous cardiac resynchronization therapy was accomplished successfully with a double cannulation approach: cannulation of the coronary sinus ostium with a catheter via a transvenous femoral vein approach and subsequent cannulation with the coronary venous lead via a left subclavian approach. When a prominent Thebesian valve is identified as an obstacle to transvenous left ventricular lead placement, cannulation of the coronary sinus by an alternate venous approach may allow for a coronary venous route rather than necessitate an epicardial approach.

Lead positioning strategies to enhance response to cardiac resynchronization therapy

Left ventricular lead position is one of the main determinants of CRT response. There are several approaches in LV lead positioning that include favoring an optimal anatomical position or targeting either the segment with maximal mechanical dyssynchrony or a region with maximal electrical delay. The conventional LV lead implantation faces several technical difficulties that may prevent the obtaining of a stable position and good performance of the LV lead without phrenic nerve stimulation. In addition, implant of the LV pacing lead in areas with myocardial scar may result in less than optimal cardiac resynchronization. Several strategies have been proposed to overcome all these obstacles including multimodality cardiac imaging to help in preprocedural or intraprocedural identification of the latest activated areas of the LV and the potential anatomical constraints. In selected patients, the surgical implant may be a solution to overcome these constraints. In the future, LV endocardial or epicardial multisite pacing may deliver an enhanced response to CRT.

[Technical innovations and limitation in cardiac electrotherapy]

Coronary sinus (CS) lead positioning is one of the main determinants of cardiac resynchronization therapy (CRT). The implantation of the CS lead is faced with several technical difficulties that may prevent the achievement of a stable position and good performance of the CS lead without phrenic nerve stimulation (PNS). New developments in catheter and lead technology to overcome these difficulties are presented.

Prospective randomized trial of venous cardiac computed tomographic angiography for facilitation of cardiac resynchronization therapy

BACKGROUND

Cardiovascular computed tomographic angiography (CTA) can visualize the coronary veins. We sought to assess the ability of CTA to facilitate resynchronization therapy (CRT) procedures using a prospective randomized single-center pilot study.

METHODS

Patients underwent CTA for characterization of cardiomyopathy prior to biventricular implantable cardiac-defibrillator implant. Randomization was performed with operator review of the CTA for coronary venous anatomy prior to CRT in one-half of the cases. Invasive coronary venous angiograms were used in all procedures. Analysis included procedure times and utilization of contrast, fluoroscopy, and guide catheters.

RESULTS

Characteristics of the 26 patients enrolled were mean age 55 ± 11 years, male 76.9%, ischemic etiology 35%, ejection fraction 25 ± 3%, class III congestive heart failure 100%, and QRS duration 179 ± 29 ms. Of patients enrolled, 22 had both CTA and procedure initiation. Three patients (two with CTA review and one without CTA review) had aborted procedures due to hemodynamic issues. Analysis of the 22 patients (nine with preprocedure CTA review and 13 without CTA review) demonstrated that preprocedure review of CTA coronary venous anatomy led to significantly decreased procedure times and utilization of contrast, fluoroscopy, and guide catheters.

CONCLUSIONS

Preprocedure review of CTA coronary venous anatomy may lead to decreased procedural times and utilization of contrast, fluoroscopy, and guide catheters. These preliminary results will need to be evaluated in larger heart failure populations undergoing CRT.

[Coronary CTA evaluation of the relationship between mitral valve annulus and coronary circulation: implications for percutaneous mitral annuloplasty]

PURPOSE

To evaluate anatomical relationships between mitral annulus (MA), coronary arteries and coronary sinus (CS) in two groups of patients with and without moderate mitral insufficiency on coronary CTA to identify candidates to percutaneous mitral valve annuloplasty via the coronary sinus without risk of coronary artery occlusion. MATERIALS AND METHODS. Fifty-one ECG-gated coronary CTA examinations, obtained during injection of iodinated contrast material on a 16 MDCT were retrospectively reviewed. The mitral valve annulus diameter, anatomical relationships between CS and coronary arteries and MA-CS distance were compared between both patient groups.

RESULTS

The group with mitral insufficiency included 16 patients and the control group included 35 patients. The AP diameter of the MA was 45,7+/-5,2 mm in the group with mitral insufficiency, significantly larger (p=0.0009) compared to the control group (39,3+/-5,9 mm). In 70.4% of cases, the CS was located next to a coronary artery in an overlapping configuration. The unfavorable anatomical configuration with regards to annuloplasty appeared related to mitral insufficiency (p=0.0539). The distance between MA and CS was greatly variable with the CS routinely extending over the left atrial surface: the distance was significantly (p=0.0002) greater for all patients along the posterior surface (8,1+/-3,8 mm) compared to the lateral surface (5,2+/-4,6 mm) with this différence persisting within both groups: p=0.004 for patients with mitral insufficiency and p=0.0001 for control patients.

CONCLUSION

Our results demonstrate the value of coronary CTA in selecting candidates to percutaneous mitral annuloplasty. In 70.4% of cases, the CS overlaps a coronary artery with risk of compression at the time of annuloplasty.

Magnetic resonance imaging and computed tomography in assessing cardiac veins and scar tissue

The success of cardiac resynchronization therapy is influenced by several issues including cardiac venous anatomy and myocardial scar tissue. This article discusses non-invasive imaging modalities that could contribute significantly to the selection process of cardiac resynchronization therapy (CRT) candidates: multi-slice computed tomography to depict the coronary sinus tributaries and magnetic resonance imaging to identify scar tissue.

Magnetic resonance cardiac vein imaging: relation to mitral valve annulus and left circumflex coronary artery

OBJECTIVES

To evaluate in vivo anatomical relationships between the coronary sinus-great cardiac vein (CS-GCV), the mitral valve annulus (MVA), and left circumflex coronary artery (LCX) with cardiovascular magnetic resonance.

BACKGROUND

The CS-GCV has become an anatomical structure of interest because it provides a way of access to the heart for a number of interventional procedures. Previous reports demonstrate that the postulated close anatomical proximity of the CS-GCV to the MVA does not always hold true in patients, both in autopsy specimens and in vivo by computed tomography.

METHODS

In 31 participants (24 volunteers and 7 patients; 15 men; 42 +/- 19 years), cardiovascular magnetic resonance was performed for noninvasive evaluation of the coronary sinus and of the coronary arteries using whole-heart imaging and intravascular contrast agents. Three-dimensional reconstructions, standard orthogonal planes, and unprocessed raw data were used to assess CS-GCV anatomy and its relation to the MVA and the LCX along their entire course.

RESULTS

The CS-GCV was located behind the left atrium in all examined participants, at a minimum distance of 8.6 +/- 3.9 mm from the MVA. In 80% of the participants, the LCX crossed the CS-GCV inferiorly, between the CS-GCV and the MVA. The CS-GCV and the LCX had a parallel course for 26.2 +/- 23.0 mm, with great variability of location and length. In several participants, the CS-GCV had a long parallel course, but in other participants, the LCX crossed below the CS-GCV at a discrete point.

CONCLUSIONS

In all participants, the CS-GCV coursed behind the left atrium rather than behind the MVA. In the majority of the participants, the LCX coursed between the CS-GCV and the MVA. These anatomical relationships should be kept in mind when referring a patient for interventional procedures requiring the access to the CS-GCV, and cardiovascular magnetic resonance might provide important information for the selection of candidates for these procedures.

Trans-Coronary-Venous Interventions

The coronary venous system is routinely targeted during electrophysiological measurements or cardiac resynchronization therapy. However, several novel interventional techniques require coronary venous catheterization and visualization as well as transvenous delivery of devices and/or therapeutic agents. Recent reports suggest the possibility of a transvenous approach for the interventional treatment of refractory angina and mitral valve regurgitation. In addition, the coronary venous system has been used as a route for the delivery of stem cells in patients with left ventricular dysfunction due to ischemic heart disease. We review the potential value of using a coronary venous approach in association with recent therapeutic developments in the interventional treatment of structural and ischemic heart disease. We will also discuss techniques related to coronary venous catheterization.

Characterization of human coronary sinus valves by direct visualization during biventricular pacemaker implantation

BACKGROUND

The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus.

OBJECTIVES

The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices.

METHODS

The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC).

RESULTS

The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization.

CONCLUSIONS

Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.

Prospective evaluation of the anatomy of the coronary venous system using multidetector row computed tomography

BACKGROUND

Multidetector row computed tomography (MDCT) is a developing technique mainly used to evaluate the coronary arteries, but less attention has been paid to the coronary venous system. However, with the dramatic technological advancement of percutaneous therapies for heart failure or mitral insufficiency, a better knowledge about the anatomy of the coronary venous system may be of great utility. We sought the efficacy of MDCT imaging to delineate the coronary venous system.

METHODS

16 row MDCT scans were performed in 50 consecutive patients (42 men, age 61+/-15 years, all in sinus rhythm). The inter-individual variability in terms of diameter, distance, angle of the main tributaries of the coronary venous system was reported.

RESULTS

The coronary venous system was always visualized. A remnant Thebesian valve was observed in 18 patients, the diameter of the coronary sinus ostium was found 12.2+/-3.6 mm and 15.3+/-3.7 mm respectively in the antero-posterior and supero-inferior directions, the distance between the posterior vein of the left ventricle (PVLV) and the anterior interventricular vein (AIV) was found 108.6+/-15.2 mm with a significant correlation with the mitral annulus diameter (p<.002) and the left ventricular diameter (p<0.01). The left marginal vein (LMV) was more often tortuous when the angle between the LMV and the great cardiac vein was less than 60 degrees (p<0.01).

CONCLUSION

16 row MDCT imaging can be used to investigate non-invasively the coronary venous anatomy and may serve as a useful tool before percutaneous therapies involving the coronary veins.

Percutaneous mitral annuloplasty through the coronary sinus: an anatomic point of view

OBJECTIVE

We assessed the anatomic relationships among the mitral annulus, coronary sinus, and circumflex artery in human cadaver hearts.

METHODS

Percutaneous posterior mitral annuloplasty has been proposed to treat functional mitral regurgitation on the basis of the proximity of the coronary sinus to the mitral annulus. However, concern remains about the ability to perform a trigone-to-trigone posterior annuloplasty and the potential for compromise of the circumflex coronary artery. Ten hearts were studied after injection of expansible foam into the coronary sinus and circumflex artery. The mitral annulus perimeter, posterior intertrigonal (T1-T2) and intercommissural (C1-C2) distance, and coronary sinus projection on the native annulus (S1-S2) were measured. The spatial geometry of the coronary sinus was correlated with the circumflex artery route and the distance with the native mitral annulus.

RESULTS

The projection of coronary sinus annuloplasty achieves at best a commissure-to-commissure annuloplasty 14.5 (6-24) mm behind each trigone: T1-T2: 74 (56-114) mm, C1-C2: 62.2 (48-80) mm, S1-S2: 59.5 (40-80) mm. The coronary sinus was distant from the native annulus (8-14 mm at the coronary sinus ostium, 13.7-20.4 mm at the middle of the coronary sinus, 6.9-14 mm at the level of the great coronary vein). The circumflex artery was located between the coronary sinus and the mitral annulus in 45.5% of cases.

CONCLUSIONS

This anatomic study highlights the 3-dimensional structure of the coronary sinus and its distance from the native mitral annulus and fibrous trigones. Human anatomic studies are mandatory for the further development of percutaneous mitral repair technology.

Visualization of the cardiac venous system using cardiac magnetic resonance

We sought to investigate the value of cardiac magnetic resonance to depict cardiac venous anatomy. For cardiac resynchronization therapy the lead for the left ventricle is usually placed by transvenous approach into a tributary of the coronary sinus (CS). Knowledge of the anatomy and variations of the cardiac venous system may facilitate the positioning of the left ventricle lead. The cardiac magnetic resonance examinations of 23 subjects (16 volunteers and 7 patients) were retrospectively analyzed. All examinations were performed using navigator-gated whole-heart steady-state free precession coronary artery imaging after administration of intravascular contrast agents (gadofosveset in volunteers; Gadomer-17 in patients). The cardiac venous system was visualized in all subjects. The most frequent anatomical variant observed (in 12 subjects [52%]) was a connection of the small cardiac vein to the CS at the crux cordis. In 10 subjects (44%) the small veins entered the right atrium independently from the CS, and the posterior interventricular vein was connected to the CS at the crux cordis. Only one subject had a disconnection between the CS and posterior interventricular vein, which entered into the right atrium independently. The mean distance of the posterior vein of the left ventricle and the left marginal vein to the ostium of the CS was 15.2+/-4.7 mm and 49.7+/-14.1 mm, respectively. In conclusion, the anatomy of the cardiac venous system and its anatomical variability can be described using cardiac magnetic resonance. Its preimplantation visualization may help to facilitate the implant procedure and to reduce fluoroscopy time.

Role of multislice computed tomography for preprocedural evaluation before revision of a chronically implanted transvenous left ventricular lead

The purpose of this study was to determine the feasibility of multislice computed tomography (MSCT) to assess the coronary sinus (CS) and its tributaries in patients who are undergoing cardiac resynchronization therapy and need a left ventricular (LV) lead revision. Preprocedural imaging modality, which may enable delineation of the cardiac venous anatomy in patients who need LV lead replacement, has not yet been evaluated. Ten patients with heart failure with previously implanted cardiac resynchronization therapy devices, who presented with worsening heart failure, were studied with MSCT and tissue Doppler imaging echocardiography before LV lead replacement. MSCT was performed to evaluate patency of the CS and coronary veins, and tissue Doppler imaging echocardiography assessed the region and the magnitude of mechanical dyssynchrony. An excellent concordance in the vein diameter, location, and status between MSCT and angiography was found. Apart from the need to perform a venoplasty in 1 patient and an unsuccessful lead explantation in another patient, all other anatomic issues were correctly predicted by MSCT. CS or vein occlusion were present in 4 patients, and in 3 of them surgical LV lead replacement was performed. Identification of a patent venous system enabling successful transvenous lead implantation was possible in 2 patients. Direct visualization of the proximity of the target vein to the phrenic nerve and the diaphragm guided lead selection and position in 4 patients. In conclusion, MSCT may be used to delineate the coronary venous anatomy in patients in whom LV lead replacement is needed to help strategize whether a transvenous or transthoracic approach may be preferred for LV lead revision.

Detection of phrenic nerves and their relation to cardiac anatomy using 64-slice multidetector computed tomography

The improved temporal and spatial resolution allowed by multidetector computed tomography (MDCT) has facilitated the noninvasive assessment of cardiac anatomy before transcatheter electrophysiologic procedures. Clarification of spatial relations of phrenic nerves and key cardiac structures is important to decrease potential complications. The purpose of this study was to reconstruct the course of the right and left phrenic pericardiophrenic bundles and their relations to cardiac structures using 64-slice MDCT. One hundred six consecutive subjects (age 61 +/- 13 years; 39% women) who underwent self-referred coronary computed tomographic angiography using 64-slice MDCT underwent retrospective assessment of the phrenic nerves contained within the pericardiophrenic bundles. The course of the nerves was outlined in relation to the left atrial appendage, coronary sinus, and cardiac veins. The ability to individually detect the left and right phrenic nerves, as well as the frequency of direct contact between the left phrenic nerve and cardiac veins, was recorded. The left phrenic nerve was identified in 78 of 106 patients (74%). It crossed the left atrial appendage (n = 72, 91%), great cardiac vein (n = 63, 80%), posterior vein of the left ventricle (n = 39, 49%), posterior interventricular vein (n = 8, 10%), and anterior interventricular vein (n = 7, 9%). Mean Hounsfield units (HUs) of the left phrenic nerve was 81 +/- 25. The right phrenic nerve was identified in 50 of 106 patients (47%). Mean HUs of the right phrenic nerve were 94 +/- 26. In conclusion, cardiac imaging using 64-slice MDCT enabled adequate detection of the left and right phrenic nerves in relation to cardiac anatomy. In the setting of electrophysiologic interventions, MDCT before a procedure may elucidate anatomic relationships and help minimize inadvertent complications.

Variability of coronary venous anatomy in patients undergoing cardiac resynchronization therapy: a high-speed rotational venography study

BACKGROUND

Imaging the coronary venous (CV) tree to delineate the coronary sinus and its tributaries can facilitate electrophysiological procedures, such as cardiac resynchronization therapy (CRT) and catheter ablation. Venography also allows visualization of the left atrial (LA) veins, which may be a potential conduit for ablative or pacing strategies given their proximity to foci that can trigger atrial fibrillation.

OBJECTIVE

The aim of this study was to provide a detailed description of CV anatomy using rotational venography in patients undergoing CRT.

METHODS

Coronary sinus (CS) size and the presence, size, and angulation of its tributaries were determined from the analysis of rotational CV angiograms from 51 patients (age 68 +/- 11 years; n = 12 women) undergoing CRT.

RESULTS

The CS, posterior veins, and lateral veins were identified in 100%, 76%, and 91% of patients. Lateral veins were less prevalent in patients with a history of lateral myocardial infarction than in patients without such a history (33% vs. 96%; P = .014). The diameters of the CS and its tributaries were fairly variable (7.3-18.9 mm for CS, 1.3-10.5 mm for CS tributaries). The CS was larger in men than in women and in cases of ischemic than in cases of nonischemic cardiomyopathy (all P <.05). The vein of Marshall, the most constant LA vein, was identified in 37 patients; its diameter is 1.7 +/- 0.5 mm, and its takeoff angle is 154 degrees +/- 15 degrees , making the vein potentially accessible for cannulation.

CONCLUSIONS

Differences in CV anatomy that are related to either gender or coronary artery disease could have important practical implications during the left ventricular lead implantation. The anatomical features of the vein of Marshall make it a feasible potential conduit for epicardial LA pacing.

Noninvasive Evaluation of Coronary Sinus Anatomy and Its Relation to the Mitral Valve Annulus

BACKGROUND

Percutaneous mitral annuloplasty has been proposed as an alternative to surgical annuloplasty. In this respect, evaluation of the coronary sinus (CS) and its relation with the mitral valve annulus (MVA) and the coronary arteries is relevant. The feasibility of evaluating these issues noninvasively with multislice computed tomography was determined.

METHODS AND RESULTS

In 105 patients (72 men, age 59+/-11 years), 64-slice multislice computed tomography was performed for noninvasive evaluation of coronary artery disease. Thirty-four patients with heart failure and/or severe mitral regurgitation were included. Three-dimensional reconstructions and standard orthogonal planes were used to assess CS anatomy and its relation with the MVA and circumflex artery. In 71 patients (68%), the circumflex artery coursed between the CS and the MVA with a minimal distance between the CS and the circumflex artery of 1.3+/-1.0 mm. The CS was located along the left atrial wall, rather than along the MVA, in the majority of the patients (ranging from 90% at the level of the MVA to 14% at the level of the distal CS). The minimal distance between the CS and MVA was 5.1+/-2.9 mm. In patients with severe mitral regurgitation, the minimal distance between the CS and the MVA was significantly greater as compared with patients without severe mitral regurgitation (mean 7.3+/-3.9 mm versus 4.8+/-2.5 mm, P<0.05).

CONCLUSIONS

In the majority of the patients, the CS courses superiorly to the MVA. In 68% of the patients, the circumflex artery courses between the CS and the mitral annulus. Multislice computed tomography may provide useful information for the selection of potential candidates for percutaneous mitral annuloplasty.

Whole-heart coronary vein imaging: A comparison between non-contrast-agent- and contrast-agent-enhanced visualization of the coronary venous system

The feasibility of three-dimensional (3D) whole-heart imaging of the coronary venous (CV) system was investigated. The hypothesis that coronary magnetic resonance venography (CMRV) can be improved by using an intravascular contrast agent (CA) was tested. A simplified model of the contrast in T(2)-prepared steady-state free precession (SSFP) imaging was applied to calculate optimal T(2)-preparation durations for the various deoxygenation levels expected in venous blood. Non-contrast-agent (nCA)- and CA-enhanced images were compared for the delineation of the coronary sinus (CS) and its main tributaries. A quantitative analysis of the resulting contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) in both approaches was performed. Precontrast visualization of the CV system was limited by the poor CNR between large portions of the venous blood and the surrounding tissue. Postcontrast, a significant increase in CNR between the venous blood and the myocardium (Myo) resulted in a clear delineation of the target vessels. The CNR improvement was 347% (P < 0.05) for the CS, 260% (P < 0.01) for the mid cardiac vein (MCV), and 430% (P < 0.05) for the great cardiac vein (GCV). The improvement in SNR was on average 155%, but was not statistically significant for the CS and the MCV. The signal of the Myo could be significantly reduced to about 25% (P < 0.001).

Non-Invasive Visualization of the Cardiac Venous System in Coronary Artery Disease Patients Using 64-Slice Computed Tomography

OBJECTIVES

This study was designed to evaluate the value of 64-slice computed tomography (CT) to visualize the cardiac veins and evaluate the relation between variations in venous anatomy and history of infarction.

BACKGROUND

Cardiac resynchronization therapy (CRT) is an attractive treatment for selected heart failure patients. Knowledge of venous anatomy may help in identifying candidates for successful left ventricular lead implantation.

METHODS

The 64-slice CT of 100 individuals (age 61 +/- 11 years, 68% men) was studied. Subjects were divided into 3 groups: 28 control patients, 38 patients with significant coronary artery disease (CAD), and 34 patients with a history of infarction. Presence of the following coronary sinus (CS) tributaries was evaluated: posterior interventricular vein (PIV), posterior vein of the left ventricle, and left marginal vein (LMV). Vessel diameters were also measured.

RESULTS

Coronary sinus and PIV were identified in all individuals. Posterior vein of the left ventricle was observed in 96% of control patients, 84% of CAD patients, and 82% of infarction patients. In patients with a history of infarction, a LMV was significantly less observed as compared with control patients and CAD patients (27% vs. 71% and 61%, respectively, p < 0.001). None of the patients with lateral infarction and only 22% of patients with anterior infarction had a LMV. Regarding quantitative data, no significant differences were observed between the groups.

CONCLUSIONS

Non-invasive evaluation of cardiac veins with 64-slice CT is feasible. There is considerable variation in venous anatomy. Patients with a history of infarction were less likely to have a LMV, which may hamper optimal left ventricular lead positioning in CRT implantation.

Cardiac computed tomography: diagnostic utility and integration in clinical practice

Cardiac applications of computed tomography (CT) is a rapidly growing diagnostic area because of the ability to visualize plaque burden (coronary artery calcification [CAC]) and luminal obstruction (computed tomographic angiography [CTA]) noninvasively. Coronary artery calcification has been validated in over 1,000 studies over the last 20 years, primarily with electron beam tomography. Studies demonstrate several indications that could aid physicians in the management of symptomatic and asymptomatic patients. Determining that a symptomatic patient has no CAC is associated with both a lower risk of an abnormal nuclear study and angiographic obstruction. The ability to detect subclinical atherosclerosis (CAC) with minimal radiation and no contrast makes this an attractive method for risk stratification. New studies demonstrate a 10-fold risk of cardiovascular events with increasing amounts of coronary calcification. The invasive nature, expense, and risk resulting from invasive angiography have been instrumental in encouraging the development of new diagnostic methods that allow the coronary arteries to be visualized noninvasively. Multislice CT, with its advanced spatial and temporal resolution, has opened up new possibilities in the imaging of the heart and major vessels of the chest, including the coronary arteries. The last decade has seen great strides in the field of cardiac imaging, particularly in the ability to visualize the coronary lumen with sufficient diagnostic accuracy. Possessing that qualification, CTA is now being used increasingly in clinical practice. As a result of having high spatial and improved temporal resolutions, this imaging modality not only allows branches of the coronary artery to be evaluated, but also allows simultaneous analysis of other cardiac structures, making it extremely useful for other cardiac applications. This paper reviews the diagnostic utility and limitations of cardiac CT and how it could be integrated into clinical practice.

Early human experience with use of a deflectable fiberoptic endocardial visualization catheter to facilitate coronary sinus cannulation

BACKGROUND

Despite improvements in cardiac resynchronization therapy (CRT) implantation techniques, a significant minority of CRT attempts are unsuccessful. Inability to cannulate the coronary sinus (CS) because of difficult anatomy is a major reason for unsuccessful CRT implantation. Direct visualization of intracardiac structures during the implant may facilitate access into the CS. The present study describes CRT implantation with the aid of an endocardial visualization catheter (EVC).

METHODS

Fifty-eight consecutive patients (mean age 72 +/- 12 years; ejection fraction 26.2% +/- 7.0%; New York Heart Association [NYHA] class 2.9) underwent CRT implantation using a steerable fiberoptic EVC (Acumen Medical, Inc., Sunnyvale, CA).

RESULTS

The EVC was able to visualize the CS ostium in all cases. The CS was successfully cannulated in 57 (98.3%) of 58 patients. The time from vascular access to CS visualization was 6 +/- 5 minutes, and the total time to CS access was 8 +/- 6 minutes. Successful left ventricle (LV) lead implantation was accomplished in 55 (94.8%) of 58 patients. Three patients who had a previous history of failed LV lead implantation were successfully implanted using the EVC.

CONCLUSION

Fiberoptic imaging of intracardiac structures during CRT implantation may be performed rapidly in a wide range of patients with an EVC. The ability to visualize right atrial anatomy may aid CS access and LV lead implantation.

Percutaneous Mitral Annuloplasty

Background— To allow performance of “stand-alone” mitral annuloplasty with minimal invasiveness, percutaneous techniques consisting of delivery into the coronary sinus (CS) of devices intended to shrink the mitral valve annulus have recently been tested in animal models. These techniques exploit the anatomic proximity of the CS and mitral valve annulus in ovine or dogs. Knowledge of a detailed anatomic relationship between the CS, coronary arteries, and mitral valve annulus in humans is essential to define the safety and efficacy of percutaneous techniques in clinical practice. We sought to determine the qualitative and quantitative anatomic relationships between CS and surrounding structures in human hearts.

Methods and Results— The distance from the CS to the mitral valve annulus and the relationship between the CS and surrounding structures were studied in 61 excised cadaveric human hearts. Maximal distance from the CS to the mitral valve annulus was found to be up to 19 mm (mean, 9.7±3.2 mm). A diagonal or ramus branch, main circumflex artery, or its branches were located between anterior interventricular vein/CS and the mitral valve annulus in 16.4% and 63.9% of cases, respectively.

Conclusions— Surgical anatomy suggests that in humans the CS is located behind the left atrial wall at a significant distance from the mitral valve annulus. Percutaneous mitral annuloplasty devices probably shrink the mitral valve annulus only by an indirect traction mediated by the left atrial wall; a theoretical risk of compressing coronary artery branches exists. Chronic studies are needed to address this problem and to determine long-term efficacy of such methods.

Percutaneous mitral annuloplasty: an anatomic study of human coronary sinus and its relation with mitral valve annulus and coronary arteries

BACKGROUND

To allow performance of "stand-alone" mitral annuloplasty with minimal invasiveness, percutaneous techniques consisting of delivery into the coronary sinus (CS) of devices intended to shrink the mitral valve annulus have recently been tested in animal models. These techniques exploit the anatomic proximity of the CS and mitral valve annulus in ovine or dogs. Knowledge of a detailed anatomic relationship between the CS, coronary arteries, and mitral valve annulus in humans is essential to define the safety and efficacy of percutaneous techniques in clinical practice. We sought to determine the qualitative and quantitative anatomic relationships between CS and surrounding structures in human hearts.

METHODS AND RESULTS

The distance from the CS to the mitral valve annulus and the relationship between the CS and surrounding structures were studied in 61 excised cadaveric human hearts. Maximal distance from the CS to the mitral valve annulus was found to be up to 19 mm (mean, 9.7+/-3.2 mm). A diagonal or ramus branch, main circumflex artery, or its branches were located between anterior interventricular vein/CS and the mitral valve annulus in 16.4% and 63.9% of cases, respectively.

CONCLUSIONS

Surgical anatomy suggests that in humans the CS is located behind the left atrial wall at a significant distance from the mitral valve annulus. Percutaneous mitral annuloplasty devices probably shrink the mitral valve annulus only by an indirect traction mediated by the left atrial wall; a theoretical risk of compressing coronary artery branches exists. Chronic studies are needed to address this problem and to determine long-term efficacy of such methods.