Evaluation of the Coronary Sinus on Chest Computed Tomography in Patients With and Without Pulmonary Artery Hypertension

Standardized Criteria for Identification of Cardiac Tamponade on Non-Electrocardiogram-gated Computed Tomography: Correlation With Echocardiographic Findings

PURPOSE

To identify imaging parameters that can help in the diagnosis of cardiac tamponade on non-electrocardiogram (ECG)-gated computed tomography (CT) of the chest.

MATERIALS AND METHODS

Retrospective analysis of 64 patients who had undergone CT and echocardiography for evaluation of cardiac tamponade. Of 64 patients, 34 were diagnosed with tamponade and underwent pericardiocentesis for further diagnosis and treatment. CT measurements obtained were: pericardial effusion (PeEff) pocket size in 6 locations (anterior, posterior, superior, inferior, right, and left lateral), pericardial thickening, diameters of the coronary sinus, upper superior vena cava, lower superior vena cava, and inferior vena cava. In addition, cardiac chamber sizes were measured. Subjective assessment of coronary sinus compression, pericardial enhancement, and pericardial thickening were also recorded.

RESULTS

Measurement of the sum of the right lateral and left lateral PeEff thickness resulted in 91.2% sensitivity and 86.7% specificity for cardiac tamponade with a threshold of 30 mm (receiver-operating characteristic area under the curve=0.94 [0.84 to 0.98], P <0.0001). Using the combination of inferior PeEff >16 mm, sum of right lateral and left lateral PeEff>30 mm, and presence of pericardial thickening resulted in 56% sensitivity and 100% specificity and positive predictive value for the determination of cardiac tamponade.

CONCLUSIONS

Our study suggests that CT measurements related to PeEff size and thickness aid in the diagnosis of cardiac tamponade.

Impact of Altered Vena Cava Flow Rates on Right Atrium Flow Characteristics

The right atrium (RA) combines the superior (SVC) and inferior vena cava (IVC) flows. Treatments like extracorporeal membrane oxygenation (ECMO) and hemodialysis by catheter alter IVC/SVC flows. Here we assess how altered IVC/SVC flow contributions impact RA flow. Four healthy volunteers were imaged with CT, reconstructed and combined into a patient-averaged model. Large Eddy Simulations (LES) were performed for a range of IVC/SVC flow contributions (30-70% each, increments of 5%) and common flow metrics were recorded. Model sensitivity to reconstruction domain extent, constant/pulsatile inlets and hematocrit was also assessed. Consistent with literature, a single vortex occupied the central RA across all flowrates with a smaller counter-rotating vortex, not previously reported, in the auricle. Vena cava flow was highly helical. RA turbulent kinetic energy (TKE) (P=0.027) and time-averaged wall shear stress (WSS) (P<0.001) increased with SVC flow. WSS was lower in the auricle (2 Pa, P<0.001). WSS in the vena cava were equal at IVC/SVC =65/35%. The model was highly sensitive to the reconstruction domain with cropped geometries lacking helicity in the vena cavae, altering RA flow. RA flow was not significantly affected by constant inlets or hematocrit. The rotational flow conventionally described in the RA is confirmed however a new, smaller vortex was also recorded in the auricle. When IVC flow dominates, as is normal, TKE in the RA is reduced and WSS in the vena cavae equalize. Significant helicity exists in the vena cava, a result of distal geometry and this geometry appears crucial to accurately simulating RA flow.

Association Between the Coronary Sinus Ostial Size and Atrioventricular Nodal Reentrant Tachycardia in Patients With Pulmonary Arterial Hypertension

Aims

The incidence of atrioventricular nodal reentrant tachycardia (AVNRT) is higher in pulmonary arterial hypertension (PAH) patients than in the general population. AVNRT is reportedly associated with a larger coronary sinus (CS) ostium (CSo). However, the correlation between AVNRT and CSo size in PAH patients is poorly investigated. We aimed to investigate the impact of CSo size on AVNRT and identify its risk factors in PAH.

Methods and Results

Of 102 PAH patients with catheter ablation of supraventricular tachycardia (SVT), twelve with a confirmed AVNRT diagnosis who underwent computed tomographic angiography were retrospectively enrolled as the study group. The control group (PAH without SVT, n = 24) was matched for sex and BMI at a 2:1 ratio. All baseline and imaging data were collected. Mean pulmonary artery pressure was not significantly different between the two groups (65.3 ± 16.8 vs. 64.5 ± 17.6 mmHg, P = 0.328). PAH patients with AVNRT were older (45.9 ± 14.8 vs. 32.1 ± 7.6 years, P = 0.025), had a larger right atrial volume (224.4 ± 129.6 vs. 165.3 ± 71.7 cm3, P = 0.044), larger CSo in the left anterior oblique (LAO) plane (18.6 ± 3.3 vs. 14.8 ± 4.0 mm, P = 0.011), and larger CSo surface area (2.08 ± 1.35 vs. 1.45 ± 0.73 cm2, P = 0.039) and were more likely to have a windsock-shape CS (75% vs. 16.7%, P = 0.001) than those without AVNRT. A linear correlation was shown between CSo diameter in the LAO-plane and the atrial fractionation of the ablation target for AVNRT (R2 = 0.622, P = 0.012).

Conclusion

Anatomical dilation of the CSo is a risk factor for AVNRT development in patients with PAH.

Coronary sinus diverticulum: Importance, function, and treatment

The importance of venous structure in the heart is usually overshadowed by that of the arterial system. Coronary sinus (CS) is a part of cardiac venous apparatus and connects left atria to the right atria. Other than having role in physiological contractions of both atria, it contributes substantially to cardiac electrical conduction system. Due to unique placement and connections of the CS, it has become growing interest in clinical cardiology. It is used in cardiac resynchronization therapy with biventricular pacing, left-sided catheter ablation of arrhythmias, and administration of retrograde cardioplegia in cardiac surgery. In some individuals, CS is presented with anatomical variants. CS diverticulum is a congenital outpouching that provides muscular connection between atria and ventricle. This connection provides a suitable substrate for occurrence of arrhythmias, which even results in life-threatening events such as sudden cardiac death. Early diagnosis leads to treatment with ablation techniques, which ultimately eliminates origins of arrhythmias.

Coronary Sinus Diameter to Inferior Vena Cava Diameter Ratio in the Diagnosis of Cardiac Tamponade: A Novel Approach

BACKGROUND

In cardiac tamponade, coronary sinus (CS) as an intrapericardial structure can be easily compressed, whereas inferior vena cava (IVC) dilates. This inverse relationship may augment their roles in the evaluation of tamponade imaging.

AIM

We assessed the usefulness of computerized tomographic measures of CS diameter and also CS/IVC ratio to predict tamponade in clinically stable patients with large pericardial effusion.

METHODS

Sixty-six clinically stable patients who had large pericardial effusions were included. Coronary sinus diameter was measured from the point at 1 cm proximal to the CS ostium. Inferior vena cava diameter was measured from the segment between its right atrial orifice and hepatic vein.

RESULTS

Patients with tamponade had smaller CS diameter and CS/IVC ratio. After adjusting with other parameters, only either CS diameter or CS/IVC ratio predicted tamponade, respectively. (Nagelkerke r value for CS was 53.7% and 72.1% for CS/IVC ratio). In Receiver Operating Characteristic Curve analysis, a cutoff value of 6.85 mm for CS diameter had 82.6% sensitivity and 83.7% specificity and a cutoff value of 27% for CS/IVC ratio had 87.0% sensitivity and 86.0% specificity for predicting cardiac tamponade.

CONCLUSIONS

The tomographic measures of both the CS diameter and the CS/IVC ratio predicted tamponade in clinically stable patients with large pericardial effusion. Compared with CS diameter, CS/IVC ratio seemed to be a more powerful predictor of tamponade.

Persistent left superior vena cava with absent right superior vena cava in adults: CT and clinical findings

PURPOSE

Persistent left superior vena cava (PLSVC) with absent right superior vena cava (ARSVC) is rare. We evaluated CT and clinical findings of adults with ARSVC.

MATERIALS AND METHODS

Our study included 11 adults with ARSVC (mean age, 63 ± 17 years). We evaluated CT findings of the azygos vein system and coronary sinus (CS) using thin slice data of > 64 MDCT. Arrhythmia and congenial heart disease were assessed. We compared the CS diameters between the ARSVC group and the control group of 120 adults with normal vena cava (mean age, 60 ± 4 years).

RESULTS

Adults with ARSVC had no azygos vein arch and the hemiazygos vein continued to PLSVCs via the superior intercostal vein. Eight adults had arrhythmia including conduction disturbance and one arrhythmia was associated with atrial septal defect. All adults with ARSVC had dilated CS larger than 11 mm. The mean diameter of the CS in the ARSVC group was 18.4 mm, and that of the control group was 6.8 mm. CS diameter in the ARSVC group was larger than that in the control group (p < 0.001).

CONCLUSION

Adults with ARSVC had dilated CS and no azygos vein arch. Four adults had conduction disturbance.

Coronary venous anatomy and anomalies

Coronary venous anatomy can be divided into the greater cardiac venous system and the lesser cardiac venous system. With protocol optimization, including appropriate contrast bolus timing, coronary veins can be depicted with excellent detail on CT. Knowledge of variant coronary venous anatomy can sometimes play a role in pre-procedural planning. Analysis of the coronary venous anatomy on CT can detect coronary venous anomalies that cause right to left shunts with risk of stroke, left to right shunts, and arrhythmias.

Relationship between severity of pulmonary hypertension and coronary sinus diameter

INTRODUCTION AND OBJECTIVE

We investigated the relationship between coronary sinus (CS) diameter and pulmonary artery systolic pressure (PASP) in patients with pulmonary hypertension (PH) and normal left ventricular systolic function.

METHODS

A total of 155 participants referred for transthoracic echocardiography were included in the study. The study population consisted of 100 patients with chronic PH and 55 control subjects. Patients with PH were divided into two groups according to PASP: those with PASP 36-45 mmHg, the mild PH group (n=53); and those with PASP >45 mmHg, the moderate to severe PH group (n=47). CS diameter was measured from the posterior atrioventricular groove in apical 4-chamber view during ventricular systole according to the formula: mean CS=(proximal CS+mid CS+distal CS)/3.

RESULTS

Mean CS diameter was significantly higher in the moderate to severe PH group than in the controls and in the mild PH group (1.12±0.2 cm vs. 0.82±0.1 cm and 0.87±0.1 cm, respectively; p<0.001). It was significantly correlated with right atrial (RA) area (r=0.674, p<0.001), RA pressure (r=0.458, p<0.001), PASP (r=0.562, p<0.001), inferior vena cava diameter (r=0.416, p<0.001), right ventricular E/A ratio (r=-0.290, p<0.001), and E/Em ratio (r=0.235, p=0.004). RA area (β=0.475, p<0.001) and PASP (β=0.360, p=0.002) were found to be independent predictors of CS diameter.

CONCLUSIONS

A dilated CS was associated with moderate to severe pulmonary hypertension, and RA area and PASP were independent predictors of CS diameter.

Coronary sinus dilatation is a sign of impaired right ventricular function in patients with heart failure

OBJECTIVE

The coronary sinus (CS) has been largely ignored by physicians due to a lack of adequate data about the importance of CS enlargement in patients with heart failure (HF). We aimed to assess whether CS dilatation develops in patients with HF and to demonstrate its relation with global myocardial function of the right ventricle (RV).

METHODS

In this cross-sectional study, 45 healthy subjects and 95 HF patients exhibiting left ventricular systolic dysfunction on echocardiographic examination (EF <45%) secondary to ischemic (n=56) or idiopathic dilated cardiomyopathy (DCM) (n=39) were enrolled. Patients with severe renal dysfunction and/or valve disease were excluded. CS was measured by echocardiography from the posterior atrioventricular groove in the apical four-chamber view. The RV myocardial performance index (MPI), which reflects both systolic and diastolic function of the ventricle, was detected using tissue Doppler imaging, and patients with an RV MPI >0.55 were defined as having impaired RV myocardial function. ANOVA, Kruskal-Wallis, Pearson's correlation, and multivariate logistic regression analyses were used for the statistical analysis.

RESULTS

The CS and RV MPI values were significantly greater both in patients with ischemic and idiopathic DCM than in controls (8.79±1.7 mm and 8.33±2.1 mm vs. 5.74±0.6 mm, and 0.64±0.07 and 0.62±0.08 vs. 0.43±0.02; p<0.001 for both, respectively). For the prediction of HF patients with impaired RV function, the cut-off value for the diameter of the CS was 7.35 mm, with a sensitivity of 83% and a specificity of 79%.

CONCLUSION

The CS diameter can be used as a novel echocardiographic marker that provides information about impaired RV function in patients with HF.

Imaging of the coronary sinus: normal anatomy and congenital abnormalities

Knowledge of the anatomy of the coronary sinus (CS) and cardiac venous drainage is important because of its relevance in electrophysiologic procedures and cardiac surgeries. Several procedures make use of the CS, such as left ventricular pacing, mapping and ablation of arrhythmias, retrograde cardioplegia, targeted drug delivery, and stem cell therapy. As a result, it is more important for physicians interpreting the results of computed tomographic (CT) examinations dedicated to the heart or including the heart to be able to identify normal variants and congenital anomalies and to understand their clinical importance. Abnormalities of the CS range from anatomic morphologic variations to hemodynamically significant anomalies such as an unroofed CS, anomalous pulmonary venous connection to the CS, and coronary artery-CS fistula. It can be important to identify some anatomic variations, even though they are clinically occult, to ensure appropriate preprocedural planning. Both CT and magnetic resonance imaging provide excellent noninvasive depiction of the anatomy and anomalies of the CS. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.324105220/-/DC1.

The dilated coronary sinus: utility of coronary sinus cross-sectional area and eccentricity index in differentiating right atrial pressure overload from persistent left superior vena cava

BACKGROUND

Pulmonary hypertension and right atrial pressure overload (RAPO) cause dilation of the coronary sinus (CS). Persistent connection of the left superior vena cava (LSVC) to the CS is another cause of CS dilation. The purpose of this study was to evaluate the usefulness of coronary sinus cross-sectional area (CSA) and eccentricity index (EI) in differentiating persistent LSVC from right heart overload and RAPO in patients with dilated CS.

METHODS

We identified 15 patients with a dilated CS by echocardiography. Offline analysis was used to measure CS-CSA and CS-EI at end-diastole in the parasternal long axis plane. EI was defined as B/A, where A is the widest diameter and major axis of the CS, and B is the diameter of the minor axis (perpendicular to and bisecting A at its midpoint). Persistent LSVC was confirmed by either computed tomography or injection of agitated saline in the left antecubital vein.

RESULTS

CS-CSA was significantly larger in PLSVC group than in group with RAPO. Also, CS-EI was lower in PLSVC than in RAPO group (P = 0.0003). EI was the most sensitive and specific discriminator between patients with persistent LSVC vs. RAPO. CS-EI was <0.8 in all PLSVC patients and >0.8 in all RAPO patients (sensitivity and specificity = 100%).

CONCLUSION

Patients with persistent LSVC have a significantly higher CS-CSA than those with elevated RA pressure. When dilated CS is present, a CS-EI <0.8 is 100% sensitive and specific for persistent LSVC. Thus, the CS-EI can be used in cases of dilated CS to diagnose the presence of persistent LSVC with a very high degree of certainty, and can help differentiate this congenital anomaly from RAPO.

Time-resolved analysis of coronary vein motion and cross-sectional area

PURPOSE

To quantify periods of low motion and cross-sectional area changes of the coronary veins during the cardiac cycle for planning magnetic resonance coronary venograms (MRCV).

MATERIALS AND METHODS

Images were acquired from 19 patients with coronary artery disease (CAD) and 13 patients scheduled for cardiac resynchronization therapy (CRT). The displacement and cross-sectional area of the coronary sinus was tracked, and periods of low motion were defined as consecutive time points during which the position of the coronary sinus remained within a 0.67-mm diameter region. Patients were classified as systolic dominant or diastolic dominant based on the relative duration of their low motion periods.

RESULTS

All CRT patients were classified as systolic dominant, and 32% of these had no separate diastolic rest period. All CAD patients with ejection fraction < 35% were classified as systolic dominant, while all CAD patients with ejection fraction > 35%were diastolic dominant. In 77% of all subjects, the cross-sectional area of the coronary sinus was larger in systole than in diastole.

CONCLUSION

The movement of the coronary sinus can be used to classify patients as either having a longer systolic or diastolic rest period. The classification of the CRT patients as systolic dominant suggests that MRCVs be acquired in systole for CRT planning; however, each patient's low motion periods should be categorized to ensure the correct period is being used to minimize motion artifacts.