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

Morphological Study of the Thebesian Valve in Fresh Autopsied Adult Human Hearts

Background The coronary sinus (CS) and its tributaries have been used to perform various electrophysiological and cardiac interventional procedures which require cannulation. The Thebesian valve (TV) guarding the coronary sinus orifice (CSO) exhibits morphological variations which might make cannulation unsuccessful leading to the failure of invasive cardiac procedures. This study aimed to analyze in detail the morphological features of the TV in fresh autopsied human hearts which were representative of the adult population of this region owing to its practical implications in invasive cardiac procedures. Methodology This was a cross-sectional, descriptive study conducted in the Department of Anatomy in collaboration with the Department of Forensic Medicine and Toxicology at Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry. A total of 104 fresh adult heart specimens were collected during the autopsy. The CSO was located, and the characteristic shape, composition, position, and extent of coverage of the CSO by the TV were observed and analyzed. Results The TV was present in 65% of heart specimens. The most common shape was remnant (33%), and the most common site of origin was inferior (63%). The valve composition was thin and membranous in 63% of heart specimens. In 7% of heart specimens, the TV covered more than 75% of the CSO diameter, of which in 4% of heart specimens, the CSO was completely closed and found to be obstructive. Conclusions This study highlights the variability in the morphological structure of the TV in adult human hearts and its potential implications in unsuccessful CS cannulation and failure of invasive cardiac procedures. Thus, prior imaging of the TV should be an integral part of CS cannulation procedures to avoid unsuccessful cannulation and complications related to repeated forceful cannulation.

Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue-Implications for Cardiac Resynchronization Therapy Leads

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20-70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.

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.

Image-guided left ventricular lead placement in cardiac resynchronization therapy: focused on image fusion methods

Cardiac resynchronization therapy is an effective and widely accessible treatment for patients with advanced, drug-refractory heart failure. It has been shown to reverse maladaptive ventricular remodeling, increase exercise capacity, and lower hospitalization and mortality rates. However, there still exists a considerable proportion of patients who do not respond favorably to the therapy. Tailored left ventricular (LV) lead positioning instead of empiric implantation is thought to have the greatest potential to increase response rates. In our paper, we focus on the rationale for guided LV lead implantation and provide a review of the non-invasive imaging modalities applicable for navigation during LV lead implantation, with special attention to the latest achievements in the field of multimodality imaging and image fusion techniques. Current limitations and future perspectives of the concept are discussed as well.

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.

Anatomical variations of the coronary sinus valve (Thebesian valve): implications for electrocardiological procedures

AIMS

The Thebesian valve (TV) can be a significant obstacle to coronary sinus (CS) cannulation. The aim of this study was to evaluate the characteristic features of the CS valve--TV anatomy. In particular, emphasis was placed on identifying specific structures of the TV that could potentially complicate CS cannulation.

METHODS AND RESULTS

We examined 273 autopsied human hearts. The height of the TV and the diameter of the CS were measured. The valves were classified according to their shape into five types: remnant, semilunar, fold, cord, and mesh and fenestrated. The mean transverse CS ostium (CSO) diameter was 12.2 ± 3.5 mm. The TV was present in 224 (82.1%) cases. The most common type of TV was semilunar: 32.6%; followed by remnant: 25.5%; fold: 17.4%; cord: 14.3%; and lastly mesh and fenestrated: 10.3%. The mean TV height for remnant-semilunar-fold types was 5.8 ± 3.0 mm. In seven cases, the present TV (2.6%) covered the entire orifice of the CS. Hearts with larger CSO diameter had lower TV height (P < 0.001).

CONCLUSIONS

We propose a new classification of the TV shapes based on the largest sample to date. We assessed that only in 2.6% of all 273 cases the presence of an obstructive TV can cause unsuccessful cannulation. The height of the TV was inversely correlated to the CSO diameter (r = -0.33; P < 0.001).

Normal anatomy and variants of the venous cardiac system in MDCT coronary angiography

Three separate venous systems drain the blood returning from the heart walls. These veins are characterised by remarkable variability in terms of frequency, size and course. The knowledge of cardiac venous anatomy is of primary importance during interventional cardiac procedures that require catheterisation of cardiac veins. Some anatomical variants may hinder or contraindicate access to target veins. Coronary angiography (CA) with multidetector computed tomography (MDCT-CA) and multiplanar reformations (MPR), maximum intensity projection (MIP) and 3D reconstructions provides noninvasive visualisation of normal cardiac veins and anatomical variants. The purpose of this pictorial review is to describe by MDCT-CA the anatomy and main variants of the cardiac venous system.

Variance in coronary venous anatomy: a critical determinant in optimal candidate selection for cardiac resynchronization therapy

BACKGROUND

Knowledge of coronary sinus (CS) anatomy and its variations is one of the important factors determining the final position of left ventricle pacing lead during cardiac resynchronization therapy.

METHODS

Coronary venous system anatomy, including number, diameter, and opening angles of tributaries, was studied in 50 normal formalin-fixed adult cadaveric hearts.

RESULTS

Thebesian valve (TV) and Vieussens valve were present in 64% and 60% cases, respectively. CS ostium coverage of ≥75% by TV was seen in 25% (8/32) cases. Number of prominent tributaries lying between anterior interventricular vein and middle cardiac vein varied from 1-4. In 28% of hearts, only one prominent tributary was present. Midlateral vein (average diameter 1.75 ± 0.66 mm) with an average distance of 43.5 ± 12.2 mm from coronary ostium was present in 58% (29/50) hearts, of which it formed an acute angle with CS axis in four (13.39%) cases. Posterolateral vein (average diameter 1.62 ± 0.45 mm) with an average distance of 33.4 ± 11.7 mm from coronary ostium was found in 72% (36/50) cases and formed an acute angle with CS in three (8.33%) cases.

CONCLUSIONS

Restrictive TV covering ≥75% CS ostium (25% cases), presence of single prominent tributary (28% cases), and formation of acute angle of tributary with CS axis (1/4 cases with anterolateral vein, 4/29 cases with midlateral vein, 3/36 cases with posterolateral vein, and 3/28 cases with posterior veins of the left ventricle) can impede successful cannulation of CS.

Prospective versus retrospective ECG-gating for 64-detector computed tomography of the coronary venous system in pigs

BACKGROUND

Multidetector computed tomography (MDCT) provides a non-invasive anatomic description of the coronary veins that may be useful in patients candidates to cardiac resynchronization. Prospective gating reduces radiation exposure but its impact on image quality is unknown is this setting.

AIMS

This study compared image quality and reliability of MDCT angiography of the coronary veins between prospective and retrospective gating.

METHODS

Seven anaesthetized pigs underwent 64-detector row MDCT with prospective and retrospective ECG-gating. MDCT scans were evaluated for visibility of the veins, estimated radiation dose and vein characteristics. Inter- and intra-observer reproducibility was calculated.

RESULTS

Visibility grades of all veins were significantly decreased in prospective (0.82 ± 0.6) compared to retrospective gating (1.68 ± 0.9; P<0.001), the lateral vein being missed in two cases when using prospective vs. retrospective gating. The maximal vein length was significantly increased when using retrospective gating (P=0.015). Inter-observer but not intra-observer reproducibility was dependent on the gating technique for the maximal length and contrast-to-noise ratio (P=0.003 for both). Heart rate was 82 ± 13 bpm and 86 ± 11 bpm during retrospective and prospective ECG-gating (P=ns) despite full dose of atenolol titration.

CONCLUSION

Retrospective gating seems to be superior to prospective gating MDCT to describe the coronary venous system but the conclusions of our study should be confined to high heart rate condition.

Non invasive cardiac vein mapping: role of multislice CT coronary angiography

PURPOSE

Coronary venous anatomy is of primary importance when implanting a cardiac resynchronization therapy device, besides, the coronary sinus can be differently enlarged depending on chronic heart failure. The aim of this study is to evaluate the usefulness of Coronary CTA in describing the coronary venous tree and in particular the coronary sinus and detecting main venous system variants.

MATERIALS AND METHODS

301 consecutive patients (196 ♂, mean age 63.74 years) studied for coronary artery disease with 64 slice Coronary CTA were retrospectively examined. The acquisition protocol was the standard acquisition one used for coronary artery evaluation but the cardiac venous system were visualized. The cardiac venous system was depicted using 3D, MPR, cMPR and MIP post-processing reconstructions on an off-line workstation. For each patient image quality, presence and caliber of the coronary sinus (CS), great cardiac vein (GCV), middle vein (MV), anterior interventricular vein (AIV), lateral cardiac vein (LCV), posterior cardiac vein (PCV), small cardiac vein (SCV) and presence of variant of the normal anatomy were examined and recorded.

RESULTS

CS, GCV, MV and AIV were visualized in 100% of the cases. The LCV was visualized in 255/301 (84%) patients, the PCV in 248/301 (83%) patients and the SCV in 69/301 (23%) patients. Mean diameter of the CS was 8.7 mm in 276/301 (91.7%) patients without chronic heart failure and 9.93 mm in 25/301 (8.3%) patients with chronic heart failure.

CONCLUSIONS

Coronary CTA allows non invasive mapping of the cardiac venous system and may represent a useful presurgical tool for biventricular pacemaker devices implantation.

Non-invasive evaluation of the coronary venous system in patients with chronic systolic heart failure by 64-detector computed tomography

BACKGROUND

Imaging coronary venous systems to guide transcatheter cardiac interventions are becoming increasingly important, particularly in heart failure patients who are selected for cardiac resynchronization therapy (CRT). Failure of left ventricular (LV) lead placement during the procedure has been attributed to the inability to insert catheters into the coronary sinus and the lack of suitable side branches.

PURPOSE

To comparatively assess the value of a 64-detector MDCT examination in visualizing the cardiac veins and evaluating the morphological characteristics of the coronary venous system in patients with and without chronic systolic heart failure (SHF).

MATERIAL AND METHODS

A 64-detector MDCT examination of the heart was performed in 26 consecutive patients (five women, 21 men; mean age 57.80 ± 12.05 years; range 27-81 years) with chronic SHF. The morphological characteristics of the coronary venous system, such as the diameter, the distances between the venous tributaries, the angle and the tortuosity, were evaluated. The group was compared with a subgroup of 52 subjects without SHF (LV ejection fraction >40%) matched for age, sex, and the risk factors for coronary artery disease.

RESULTS

The coronary sinus (CS), great cardiac vein (GCV), anterior interventricular vein (AIV), and posterior interventricular vein (PIV) were visualized in all 78 individuals. The posterior vein of the left ventricle (PVLV) (63/78), left marginal vein (LMV) (72/78), and the small cardiac vein (SCV) (50/78) were visualized in SHF and control patients (p = NS). The lengths between venous tributaries were higher (p > 0.05) and more dilated (P < 0.001 for CS, GCV, AIV, PVLV, LMV; p = 0.001 for PIV) in the cases with SHF compared with the control population. The angle between the CS-GCV axis and the venous branches was wider (p = 0.02 for LMV and PIV, p = 0.001 for PVLV) and did not have any correlation with the LV diameter in cases with SHF. There was no difference between the SHF and control groups in terms of the tortuosity of PVLV and LMV (p = NS).

CONCLUSION

The study demonstrated an increase in the diameters, lengths, and angulations with the CS-GCV axis of the coronary veins in cases with SHF. A 64-detector MDCT is a feasible tool for non-invasive evaluation of the coronary venous system and may provide considerable information regarding numbers and morphology of coronary veins before percutaneous transcatheter cardiac therapy.

Coronary sinus ostium: the key structure in the heart's anatomy from the electrophysiologist's point of view

There are no research studies that comprehensively analyze, with computed tomography, the coronary sinus (CS) ostium with respect to its importance for some electrophysiological procedures paying special attention to the Thebesian valve (ThebV). Our aim was to evaluate the characteristic features of the CS anatomy, which can be useful for electrophysiologists using multislice computed tomography (MSCT). An additional aim was to create a tomographic classification of ThebV types. Included into the study were 150 patients (aged 59.7 ± 11.4; 105M) (43 with heart failure). Due to the suspicion of coronary artery disease, 64-slice MSCT (Toshiba, Aquilion 64) was performed in all patients. All measurements and the search for the ThebV were performed on multiplanar reconstructions in axial projection at 0.5-mm slice thickness. The average diameter of CS ostium was 14.2 ± 3.5 mm and the angle of entrance of the CS to the right atrium was 112° ± 11°. Seven variants of the ThebV were introduced and six of them were confirmed in this group. The following frequency of variants of ThebV was confirmed: E, 11.3%; D, 10.6%; A1, 8.7%; A2, 7.4%; C, 6.0%; B2, 2.0%. A statistically significant correlation between age and the size of CS ostium was found (r = 0.25; p < 0.05). It is possible to visualize and evaluate the CS including measurements and ThebV evaluation in MSCT. Six anatomical variants of the valve were found. MSCT can potentially provide valuable knowledge before the CS cannulation.

CT applications in electrophysiology

In recent years, extraordinary advances have been made in the management of cardiac arrhythmias. Increasingly complex procedures are being performed, and the breadth of conditions for which invasive arrhythmia therapy is indicated continues to grow. In addition to atrial and ventricular ablation procedures for treating arrhythmias, implantable defibrillators and biventricular pacemakers for cardiac resynchronization therapy have made electrophysiology an important part of heart failure management.

Accuracy and usefulness of fusion imaging between three-dimensional coronary sinus and coronary veins computed tomographic images with projection images obtained using fluoroscopy

AIMS

Coronary sinus (CS) and coronary veins are not delineated by fluoroscopy. The study evaluates the feasibility and accuracy of cardiac tomography (CT) image registration of CS anatomy on fluoroscopic image.

METHODS AND RESULTS

Eighteen consecutive patients underwent contrast-enhanced, ECG-gated CT scanning. Coronary sinus, coronary veins, superior vena cava, the distal portion of the trachea, and of the two main bronchi were reconstructed. These images were then fused over the CS fluoroscopic angiogram. Registration accuracy was verified by assessing the overlap of CS borders both in the CT- and in the fluoroscopy-derived images. The mean distance between the centrelines of the CS was 0.73 mm, with a maximum distance of 2.22 mm. For the first-order branches, mean distance was 0.80 mm with a maximum distance of 2.64 mm. High Lin concordance correlation coefficients were computed (>0.95) for the CS and first-order branch diameters, although the Bland and Altman limits were large. The agreement between the number of vessels identified was moderate with kappa = 0.43.

CONCLUSION

Fusion imaging processing of two different imaging modalities (CT and fluoroscopy) may be feasible and accurate for guiding CRT implantation as it allows constant comprehensive display of CS body and branches. Prospective studies are needed for assessing clinical implications.

MDCT evaluation of the cardiac venous system

PURPOSE

This study was undertaken to evaluate the usefulness of electrocardiographically (ECG)-gated multidetector-row computed tomography (MDCT) for the assessment of the coronary venous system and detection of its anatomical variants, in order to identify those suitable for lead placement in cardiac resynchronisation therapy (CRT).

MATERIALS AND METHODS

We retrospectively examined the coronary MDCT studies of 89 patients (73 males, 16 females, average age 62.5 years, range 31-79) referred for suspected coronary artery disease. The cardiac venous system was assessed in all patients using three-dimensional (3D) postprocessing on a dedicated Vitrea workstation (five patients were excluded from the analysis).

RESULTS

The coronary sinus, the great cardiac vein, the anterior interventricular vein and the middle cardiac vein were visualised in all cases. The lateral cardiac vein was visualised in 56/84 patients (67%) and the posterior cardiac vein in 63/84 patients (75%), never both missing. Along the postero-lateral wall of the left ventricle, only one branch was present in 44 cases, two branches in 21 cases and three or more branches in 19/84 cases (22%). Evaluation of the maximum diameter revealed that the lateral vein was dominant over the posterior vein in 20/40 cases. The small cardiac vein was visualised in 11/84 cases.

CONCLUSIONS

MDCT provides good depiction of the cardiac venous system, enabling the study of the vessel course and the identification of anatomical variants. Hence, this imaging technique could be proposed for the preoperative planning of CRT in selected patients.

Influence of left atrial and ventricular volumes on the relation between mitral valve annulus and coronary sinus

The aim of this study was to evaluate the anatomic relation between the coronary sinus (CS), mitral annulus, and coronary arteries using 64-multislice computed tomography (MSCT) in patients presenting with a wide range of atrial volumes and left ventricular functions to determine the potential clinical use for percutaneous mitral annuloplasty (PMA). The MSCT data of 165 patients (age 63.65 +/- 12.89 years, 67.3% men) were evaluated. The following variables were measured: CS length, CS ostium area, area of the section of CS when it becomes great cardiac vein, area between CS and atrioventricular groove assessed in volume-rendered 3-dimensional images, axial angle measured as the angle between CS and mitral annulus assessed in axial section, mitral valve annulus (MVA) area, left atrium volume, and left circumflex artery/marginal branch-CS relation referring to mitral annulus. The correlation was inversed between the reduction of the axial angle and all following variables: enlargement of both left ventricular end-systolic (r = -0.429, p <0.001) and end-diastolic (r = -0.428, p <0.001) volumes, left atrial volume (r = -0.361, p <0.001), and MVA (r = -0.324, p <0.001). Similarly, there was inverse correlation between the reduction of the area between CS and atrioventricular groove, and enlargement of both left ventricular end-systolic (r = -0.376, p <0.001) and end-diastolic (r = -0.291, p <0.001) volumes, left atrial volume (r = -0.221, p = 0.001), and MVA (r = -0.155, p = 0.019). Of note, circumflex artery was located between CS and MVA in 77% of the patients, but in patients with severe mitral regurgitation CS crossed circumflex/marginal branch artery more frequently (97% of cases). In conclusion, a close proximity of the CS to the mitral annulus but also to circumflex artery is more likely to occur with left atrial and ventricular enlargement. Thus, MSCT should be considered as part of the selection process of potential candidate to PMA to avoid external compression of circumflex artery/marginal branch by the device.