Prevalence, management, and prognosis of isolated coronary artery fistulas: a 12-year single-center retrospective computed tomographic study

Introduction

Coronary artery fistulas (CAFs) are a rare congenital anomaly characterized by an abnormal connection between the coronary arteries and other heart chambers or vessels. A significant proportion of individuals with CAFs remain clinically asymptomatic, particularly with small fistulas, which may even close spontaneously over time (1). Although the larger CAFs have the potential to cause symptoms, they are frequently identified incidentally during diagnostic evaluations for concurrent cardiovascular conditions or on routine cardiac imaging performed for health examinations (2). The reported prevalence of CAFs varies widely, largely due to differences in imaging modalities and heterogeneity among study populations. Previous studies have shown a prevalence of 0.3–0.8% among adults undergoing cardiac angiography (3) and from 0.17% to 0.9% in cohorts evaluated by coronary computed tomography angiography (CCTA) (4,5). Symptoms such as chest pain, dyspnea, or fatigue, even when arising from larger CAFs, may be mistakenly ascribed to more prevalent cardiovascular conditions, thereby overshadowing the need for targeted management of CAFs. Consequently, there remains a notable lack of understanding regarding the prevalence, symptoms, and current management of patients with isolated CAFs (ICAFs) and warrants further investigation. To address this gap and further advance the understanding of ICAFs, we conducted a 12-year single-center retrospective computed tomography study to provide new insights into the prevalence, anatomical features, and clinical implications of ICAFs in the adult population. We present this article in accordance with the STROBE reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-24-2242/rc).

Methods

Study population

This retrospective study utilized the picture archiving and communication system (PACS) to review all patients who underwent dual-source CCTA at Fuwai Hospital from 2010 to 2022, with clinical indications including suspected coronary artery disease, assessment of congenital heart disease, preoperative evaluation, and routine health examination. Inclusion criteria: (I) underwent dual-source CCTA with good image quality, defined as clear visualization of the coronary arteries with sharp vessel borders, absence of significant motion or artifacts, and sufficient contrast opacification allowing assessment of vessel course, diameter, and fistulous morphology; (II) complete case records. Exclusion criteria: (I) diagnoses without CAFs; (II) suspected CAFs; (III) concurrent acquired heart diseases such as coronary artery disease (CAD) and valvular heart disease (VHD); (IV) other congenital heart diseases (CHD); (V) pediatric patients (≤18 years). Demographic data, clinical presentation, and treatment information were collected via the electronic medical record system. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by institutional ethics board of Fuwai Hospital (No. 2023-1926) and individual consent for this analysis was waived due to the retrospective nature.

Dual-source CCTA protocol

All imaging procedures were conducted using the dual-source CCTA (SOMATOM Definition, Siemens Healthcare, Erlangen, Germany), with parameters set to either 100 or 120 kV for tube voltage and 420 to 500 mAs for tube current, adjusted based on the patient’s body mass index. Data acquisition commenced at the 70% phase of the RR interval, with flexibility to adjust and minimize image artifacts according to the patient’s heart rhythm. Image reconstruction featured contiguous slices with a thickness of 0.75 mm and an increment of 0.4 mm, using a medium smooth-tissue convolution kernel (I26f). Subsequently, all images were processed and analyzed on a dedicated workstation (Multimodality Workplace, Siemens Healthcare, Erlangen, Germany). In addition to conventional axial slices, multiple planar reconstructions, curved planar reconstructions, maximum intensity projections, and volume rendering were used to ensure a comprehensive evaluation of the images.

Image revaluation

Two radiologists (L.X. and J.W.) with over ten years of experience in cardiovascular radiology independently reviewed the CCTA images to determine the anatomical characteristics of ICAFs utilizing multiplanar reformation and volume rendering techniques, with no prior knowledge of scan parameters or patient demographics. The evaluation criteria included: (I) origin, with multiple origins were defined as simultaneous multivessel anomalous vessels arising from bilateral coronary arteries or unilateral coronary artery; (II) drainage site, with multiple drainage sites defined as distinct and separate drainage points into one or more cardiac chambers or vessels, whereas plexus-like morphology was characterized by a network of fine, tortuous channels without a single dominant drainage vessel (6); (III) size of the fistula, categorized into small, medium, or large if the fistula diameter is <1, ≥1 to 2, or >2 times the largest diameter of the coronary vessel not feeding the coronary fistula, respectively (2); (IV) coronary dilatation, further divided into segmental dilatation (focal) or diffuse dilatation (involving a long segment or the entire artery) (7); (V) coronary artery aneurysms, defined as dilatations ≥1.5 times the adjacent normal segment, with those exceeding 20 mm or four times the reference vessel considered giant (8). The fistula diameter was measured at the site of maximal caliber along the fistulous tract (2). ICAFs were further classified as coronary-pulmonary artery fistulas (CPAFs) and coronary-cameral fistulas (CCFs) according to whether the drainage site was pulmonary artery (PA) or not. In instances of evaluative discrepancy, a third experienced radiologist (G.Z.) independently assessed and then voted to reach consensus.

Statistical analysis

Continuous variables were expressed as mean ± standard deviation (SD) for normally distributed data, or median with interquartile range (IQR) for data not normally distributed, as determined by the Shapiro-Wilk test. Categorical variables were summarized as frequencies and percentages. Comparisons between groups for continuous variables were made using the Student’s t-test for normally distributed data or the Mann-Whitney U test for non-normally distributed data. For categorical variables, the Chi-squared test or Fisher’s exact test was employed, depending on the expected cell frequencies.

To investigate the factors associated with symptomatic ICAFs, univariate logistic regression analyses were initially conducted for the following variables: age, gender, comorbidities, origin, termination, classification of the ICAFs, presence of multiple origins, presence of multiple draining sites, presence of aneurysm, and the size of fistula. Variables with a P value <0.05 in the univariate analyses were considered statistically significant and were subsequently included in the multivariate logistic regression model to adjust for potential confounders and to identify independent predictors of symptomatic ICAFs. All tests were two-tailed, and P values <0.05 were considered statistically significant for all analyses. The statistical analyses were performed using R (R x64 version 4.0.2, R Foundation for Statistical Computing, Vienna, Austria).

Outcomes and follow-up

The primary endpoint of this study was patient management, which included surgical closure (SC), transcatheter closure (TCC), and observational follow-up. Indications for transcatheter or surgical closure of CAFs included the presence of symptoms, complications, and a significant shunt (9). The choice of treatment (surgical or transcatheter) was determined by patient characteristics, institutional expertise, and clinical assessment. Secondary endpoints focused on the procedural success rate and long-term procedural complications, including fistula recanalization, which was defined as the presence of blood flow through a previously occluded fistula, and the rate of reintervention. Follow-up was performed by reviewing patients’ medical records at our center and through scheduled telephone contacts at 1, 6, and 12 months post-procedure, and annually thereafter.

Results

Study cohort

A flowchart of included and excluded patients is shown in Figure 1. The final cohort comprised 252 patients, with an average age of 48.29±15.03 years, of which 47.20% were male. It indicated that the prevalence of ICAFs was 0.07% among adult population who underwent CCTA. As shown in Table 1, the prevalence of CAFs in our study was further compared with that reported in previously published cohorts. The baseline characteristics of the final cohort and anatomical characteristics of the fistulas are shown in Table S1. They were divided into treated group (N=98) and untreated group (N=154) according to whether they received treatment or not. The average follow-up time of the treated and untreated groups was 69.08±43.19 and 69.99±38.25 months, respectively. The patients in the treated group were significantly younger (40.45±14.4 vs. 53.28±13.21 years, P<0.001) and smaller (23.89±3.7 vs. 26.03±4.14 kg/m², P<0.001) than those in the untreated group. Unexpectedly, the incidence of comorbidities was substantially higher in the untreated group. Regarding clinical manifestations, 54.37% of the patients in the whole group were asymptomatic, 9.92% had heart murmur, 16.27% had chest pain, 11.9% had palpitations, 17.46% had fatigue after activity, and 1.19% had infective endocarditis. The proportion of asymptomatic patients was significantly greater among the untreated group when compared to their treated counterparts.

Figure 1 Study flow chart. CAFs, coronary artery fistulas; CTA, computed tomography angiography.

Anatomical characteristics of the ICAFs

In the whole group (N=252), the majority originated from the left anterior descending artery (LAD; 30.56%) and drained into the PA (62.3%) (Figure 2). The study identified 25.4% of patients with multiple origins, 23.41% with bilateral coronary artery origins, 77.38% with proximal origins, 30.56% with multiple drainage sites and 15.08% with plexus-like morphology. Additionally, 53.57% presented with coronary artery dilation while 29.76% presented with coronary aneurysm. The mean diameter of the fistula was 7.30±5.19 mm with 32.54% were categorized as with large ICAFs.

Figure 2 Anatomic features of the fistulas among 252 ICAFs patients. (A) Distribution of termination sites of the fistulas. (B) Distribution of origin sites of the fistulas. CS, coronary sinus; IVC, superior vena cava; LA, left atrium; LAD, left anterior descending branch; LCX, left circumflex branch; LM, left main coronary artery; LV, left ventricle; PA, pulmonary artery; RA, right atrium; RCA, right coronary artery; RV, right ventricle.

Notably, patients in the treated group predominantly had fistulas originating from the right coronary artery (RCA; 47.96%) and terminating in the left ventricle (LV; 39.80%) while that in the untreated group originated more from the LAD (41.56%) and terminated in PA (91.56%) (Figure 3). The presence of multiple origins, multiple drainage sites and plexus-like morphology were more common in the untreated group than in the treated group. Furthermore, patients in the treated group had larger fistula in diameters (8.34±5.32 vs. 3.87±2.74 mm, P<0.001), and coronary artery dilatation and aneurysms were more frequently observed.

Figure 3 Isolated CAFs from common origins. (A) LAD-PA fistula; (B) aneurysmal RCA-RA fistula; (C) LCX-RA fistula; (D) multiple RCA-PA fistulas. CAFs, coronary artery fistulas; LAD, left anterior descending; LCX, left circumflex; PA, pulmonary artery; RA, right atrium; RCA, right coronary artery.

There are 252 patients with a total of 318 fistulas in the whole group. In terms of the origin sites of 318 fistulas, 42.77% (N=136) were LAD, 42.14% (N=134) were RCA, 5.66% (N=18) were left main coronary artery (LM), and 9.43% (N=30) were left circumflex branch artery (LCX) (Figure 4).

Figure 4 Venn diagram demonstrate the distribution of origin sites of fistulas in 252 patients with ICAFs and the corresponding numbers of patients. Pink, yellow, green, and purple areas represent origins from the LAD, RCA, LM, and LCX arteries, respectively. Overlapping areas indicate fistulas originating from multiple coronary arteries. The numbers shown correspond to the number of patients. ICAFs, isolated coronary artery fistulas; LAD, left anterior descending; LCX, left circumflex; LM, left main coronary artery; RCA, right coronary artery.

Symptomatic versus asymptomatic ICAFs

There were 252 ICAFs patients further divided into symptomatic ICAFs (N=115) and asymptomatic ICAFs (N=137) groups (see Table 2). Symptomatic ICAFs patients were younger compared to their asymptomatic ICAFs counterparts (43.81±14.18 vs. 52.05±14.73 years, P=0.016) and showed less prevalence of diabetes (1.74% vs. 15.33%, P=0.036) and hyperlipidemia (11.30% vs. 43.80%, P=0.002). Anatomically, both symptomatic and asymptomatic ICAFs patients predominantly had fistulas originating from LAD. Regarding termination, the right heart was significantly more common in asymptomatic ICAFs patients (90.51% vs. 68.70%, P<0.001). The symptomatic ICAFs group had a higher incidence of coronary artery dilation (71.30% vs. 38.69%, P<0.001) and aneurysms (46.96% vs. 15.33%, P<0.001), with a notable proportion of large fistulas (54.78% vs. 13.87%, P<0.001). Specifically, the average diameter of the draining site was larger in symptomatic ICAFs group (7.95 vs. 5.85 mm, P=0.033). To note, asymptomatic ICAFs were more likely to have fistulas with multiple origins and plexus-like morphology.

Risk factors associated with symptomatic ICAFs

Univariate regression analysis identified statistically significant factors associated with symptomatic ICAFs, including age, size, coronary artery dilatation, aneurysm, multiple origins, multiple drainage sites, and ICAFs type. Surprisingly, fistulas with multiple origins and multiple draining sites appeared to be protective factors, associated with a lower risk of symptoms. The multivariate regression model adjusted for potential confounders and showed that large fistula remained a significant predictor with a threefold increase in risk [odds ratio (OR) 3.00; 95% confidence interval (CI): 1.17–7.69; P=0.022], as shown in Table 3.

Clinical outcomes

IACFs patients underwent treatment

The baseline characteristics of the patients in the treated group and anatomical characteristics of the fistulas are shown in Table S1. There were 70 patients in the TCC group and 28 patients in the SC group, with no significant differences in demographic or fistula anatomical features between the groups. Seventy-two (73.47%) patients underwent treatment within 6 months following the diagnosis of ICAFs by CCTA, while the remaining patients had an interval of 5 (1, 12.5) years.

Patients treated with TCC reported more chest pain (35.71% vs. 14.29%, P=0.036) and had higher rates of segmental coronary dilation (75.71% vs. 46.43%, P=0.013) than those underwent SC. In the TCC group, 11 patients failed attempted closure due to various challenges: failure to establish an arteriovenous loop (N=2), compression of adjacent structures (N=2), failure to anchor (N=2), inaccessible fistula (N=4), and intraoperative retrieval of the occluder due to patient-reported discomfort (N=1), as catalogued in Table 4. Thus, TCC was deemed impracticable for 15.71% (11/70) of patients initially considered candidates for TCC. Of the 59 patients in whom occluder was successfully implemented, deployment approach included the anterograde arterial approach, arterio-arterial loop, and arteriovenous loop in 21 (35.59%), 16 (27.12%), and 22 (37.29%) patients, respectively. The occlusion devices comprised ventricular septal defect occluders (N=1), vascular plugs (N=9), coils (N=15), and patent ductus arteriosus occluders (N=34). Post-deployment angiography revealed no or trivial residual shunts in 47 patients (79.66%) and mild residual shunts in 12 patients (20.34%). One patient with a fistula draining into the coronary sinus required intraoperative occluder retrieval due to coronary sinus compression, impaired venous return and resulted in patient-reported chest pain. Thus, the procedural success rate was 77.97% (46/59). Transient ST-T segment alterations on electrocardiograms were noted in 6.78% (4/59) of cases. In terms of procedural complications, no death, coronary artery dissection, myocardial infarction, or device embolization were recorded. Over an average follow-up of 69.08±43.19 months, the fistula recanalization rate, reintervention rate, and stroke rate were 10.17%, 5.08%, and 3.39%, respectively.

In the TCC group, five patients required conversion to surgery after unsuccessful interventional attempts, yielding a total of 33 patients who underwent surgical closure (28 from the SC group and five from the TCC group). The surgical techniques employed included off-pump epicardial ligation combined with aneurysm resection (N=2), off-pump epicardial ligation (N=8), epicardial ligation under cardiopulmonary bypass (CPB) (N=2), endocardial closure combined with aneurysm resection and coronary artery bypass grafting under CPB (N=5), and endocardial closure under CPB (N=16). Post-deployment angiography revealed mild residual shunts in one patient. Additionally, there was a patient required extracorporeal membrane oxygenation and intra-aortic balloon pump support due to circulatory collapse and discharged smoothly. Over an average follow-up of 91.41±41.94 months, the recanalization and reintervention rates were 12.12% (4/33) and 3.03% (1/33), respectively.

ICAFs patients without treatment

Among the cohort of 154 patients who remained untreated, five patients with indications for intervention opted against it due to personal reasons. The success rate of follow-up was 68.18% (N=105) with the average duration of follow-up being 69.99±38.25 months. Within the observation period, 4 (3.81%) patients reported experiencing chest pain, 7 (6.67%) experienced dyspnea on exertion, and 8 (7.62%) experienced palpitations. Furthermore, four patients underwent radiofrequency ablation for new-onset atrial fibrillation, and two required percutaneous coronary intervention for new-onset CAD. Regarding physical well-being, 79 patients (75.24%) experienced no limitations in physical activity, whereas 26 individuals (24.76%) faced mild restrictions. On the psychological front, seven patients (6.67%) experienced intense anxiety since the diagnosis of ICAFs by CCTA, 56 patients (53.33%) experienced occasional anxiety, and 42 patients (40%) remained indifferent to their diagnosis. In the entire cohort, 89.52% of patients were either never or only occasionally subjected to follow-up assessments, a mere 10.48% underwent regular annual reviews. One patient presented with suspected spontaneous closure of the fistula on echocardiography at 6 years of follow-up.

Discussion

In our 12-year retrospective CCTA study, we analyzed 252 patients with ICAFs, focusing on the differences in demographics, anatomical features, and clinical outcomes between symptomatic and asymptomatic patients, as well as those who underwent treatment versus those who did not. We present the following major findings: (I) ICAFs’ prevalence was 0.07% among adult population who underwent CCTA, predominantly originating from the LAD (30.56%) and draining into PA (62.3%); (II) 54.37% of ICAFs patients were asymptomatic, with large fistulas significantly associated with symptoms; (III) the majority of patients (73.47%) underwent treatment within six months of diagnosis, contrasting with a minority experiencing a delay in 5 (1, 12.5) years; (IV) TCC was not feasible for 15.71% of patients initially deemed suitable for the procedure; (V) most untreated ICAFs patients maintained their physical activity levels and occasionally experienced anxiety.

Imaging advances in diagnosis of ICAFs

Despite its invasive nature, conventional coronary angiography remains standard diagnostic modality for CAFs, owing to its unparalleled capacity to elucidate the hemodynamic intricacies of these fistulas. The landscape of diagnostic imaging for CAFs has been significantly reshaped by recent technological advancements, particularly with the advent of CCTA. This modality’s advanced imaging capabilities allow comprehensive delineation of fistula pathways, origins, and terminations, thereby enhancing diagnostic accuracy and guiding therapeutic planning (4). Moreover, CCTA has emerged as the preferred imaging modality, outstripping traditional coronary angiography and transthoracic echocardiography in diagnostic efficacy (18). The proliferation of CCTA utilization has concomitantly escalated the incidental detection of CAFs, culminating in a heightened reported prevalence (5). Nonetheless, the realm of research conspicuously lacks comprehensive investigations into ICAFs. Liemena et al. have documented a prevalence rate of 0.44% for CAFs among adults devoid of CHD, albeit without excluding subjects with concurrent CHD and VHD (19). In our study, the prevalence of CAFs was 0.5%, similar to that reported in previous studies. Notably, through a systematic review of clinical data encompassing 378,556 patients, we found for the first time that the prevalence of ICAFs was 0.07%.

Anatomical features of ICAFs

Qureshi et al. (20) have identified the RCA as the predominant site of origin for CAFs, constituting approximately 50% of cases. However, contemporary coronary angiography and CCTA studies predominantly indicate the LAD as the most frequent origin site, accounting for 59.22–67.7% (16,21). Notably, even after mitigating confounding factors attributed to diverse imaging modalities, certain CCTA study reveal that CAFs most commonly originate from RCA (17). This discrepancy extends to the termination sites of CAFs, with some studies advocating the right ventricle as the prevalent drainage site (22), whereas a larger body of research supports PA as the most common terminations (21). The apparent inconsistency regarding the typical origination and termination sites of CAFs might stem from the heterogeneity within study populations. Through meticulous inclusion and exclusion criteria, our study evaluated 252 adult patients with ICAFs, whose anatomical origins were nearly evenly distributed between the LAD (30.56%) and RCA (29.76%), while a smaller proportion originated from the LCX (8.33%). This investigation enriches the anatomical characterization of ICAFs by delineating: (I) small fistulas predominate (54.37%); (II) a noteworthy prevalence of multiple origins and bilateral coronary artery origins, each constituting 25.4% and 23.41% respectively; (III) 5.08% are plexus-like morphology; and (IV) coronary artery dilatation in 53.57% of patients, with 29.76% progressing to coronary artery aneurysms.

Clinical manifestations of ICAFs

The pathophysiological manifestations of CAFs are influenced by the flow resistance created by the pressure differential between the coronary artery and the drainage site, which is affected by the fistula’s size and tortuosity. Continuous left-to-right shunting occurs when the drainage site is in the low-pressure right heart chambers, often leading to right heart volume overload and potentially coronary steal syndrome causing angina (23). Conversely, left-to-left shunting into the high-pressure LV can cause left heart volume overload, mimicking aortic regurgitation and potentially triggering left-sided heart failure (24). This is because the LV pressure markedly decreases during diastole, which allows run-off from the coronary artery into the LV, eventually resulting in chronic LV volume overload similar to aortic regurgitation. Additionally, about 20% of CAF patients have other CHD such as Tetralogy of Fallot and pulmonary atresia (25). Given the nonspecific symptoms of CAFs, it is challenging to assess whether CAFs also contribute to the symptoms when coexisting with CAD, VHD and other CHD. This study offers a new perspective on ICAFs’ clinical manifestations, revealing a majority (54.37%) are asymptomatic, with dyspnea on exertion being the most prevalent symptom (17.46%), and infectious endocarditis the least (1.19%), without heart failure symptoms. Of note, the lower incidence of diabetes and hyperlipidemia in symptomatic ICAFs patients is likely attributable to their younger age, consistent with age-dependent epidemiological patterns of cardiometabolic diseases, rather than a direct pathophysiological effect of ICAFs. Furthermore, Liemena et al. found that CAFs’ anatomical features (large-sized, mixed and multiple, and aneurysmal) in CAD-free adults were associated with significant clinical symptoms (19). Interestingly, fistulas with multiple origins or multiple drainage sites were associated with fewer symptoms in our study. This may be because such fistulas more frequently drain into the pulmonary artery, where the right-sided circulation has lower pressure and higher compliance, making it more tolerant to shunt flow and thereby reducing the likelihood of clinical manifestations. Nevertheless, this finding should be interpreted cautiously and confirmed in future studies. Our study confirmed through multivariate logistic regression that large-sized are the only anatomical features significantly associated with clinical symptoms in patients with ICAFs (OR 3.00; 95% CI: 1.17–7.69; P=0.022).

Prognosis of ICAFs

Currently, there are two primary treatments for CAFs: SC and TCC. TCC are increasingly favored due to their minimal invasiveness, generally yielding positive outcomes with lower complication rates compared to SC. Nevertheless, SC retains its applicability for cases deemed unsuitable for TCC, including distal CAFs, complex fistulas, high-flow fistulas, or those complicated by aneurysms or multiple drainage sites (26). This investigation endeavors to bridge the extant knowledge void concerning the applicability of TCC, demonstrating its feasibility in 84.29% of the instances examined. Surprisingly, most patients (73.47%) underwent treatment within six months of CCTA diagnosis, while 26.53% were treated after an interval of 5 (1, 12.5) years. Recanalization remains a common concern for both treatments (2). This study reveals similar fistula recanalization rates postoperatively between SC and TCC, at 12.12% and 10.17% respectively, suggesting that treatment preference should prioritize the anatomical characteristics of ICAFs.

Current guidelines for the treatment of CAFs recommend closure for large fistulas or small-moderate ones presenting with severe symptoms (27). This criterion served as a major determinant in the treatment decisions for ICAFs in our study. Previous reports have indicated that asymptomatic adult patients with CAFs can remain symptom-free for one or two decades (28), leading to a neglect of regular monitoring for progression in fistula size or cardiac chamber changes, which could result in severe complications such as spontaneous rupture and cardiac tamponade (29). In our cohort, the follow-up success rate in the untreated group was only 68.18%, with 40% of patients showing no behavioral change after diagnosis and most experiencing only occasional anxiety. As a result, regular follow-up was rare. These findings highlight the importance of improving awareness and surveillance among patients who do not undergo immediate treatment.

Limitations

There are several limitations in this study. Firstly, this study’s single-center, retrospective design limits the generalizability of its findings, potentially introducing selection and indication biases. Secondly, although CCTA outperforms echocardiography and coronary angiography in detecting CAFs due to its high spatial resolution, three-dimensional multi-planar reconstruction capability, and independence from motion artifacts (26), some small ICAFs may still be misinterpreted as anatomical variants. This could lead to underreporting and an underestimation of their true prevalence. Thirdly, re-evaluation of CCTA images under strict quality control led to the exclusion of many patients with poor image quality, potentially resulting in an underestimation of ICAF prevalence. Fourthly, as a retrospective study, treatment decisions such as SC or TCC may have been partly influenced by physician preference or institutional practice, rather than strictly anatomical indications, which could not be fully assessed. Fifthly, high loss to follow-up among untreated ICAF patients and the variability in identifying postoperative outcomes, including recanalization, may have introduced some uncertainty in the reported results.

Conclusions

In the present 12-year single-center retrospective CCTA study, we found that 30.56% of ICAFs originated from the LAD and 62.3% drained into PA with reported the prevalence of 0.07% among adult population who underwent CCTA for the first time. It is recommended that treatment preference should prioritize the anatomical characteristics of ICAFs. Notably, transcatheter closure was not feasible for 15.71% of patients initially deemed suitable for the procedure. Furthermore, although the majority of ICAFs were asymptomatic, large fistulas were the only anatomical features significantly associated with clinical symptoms.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-24-2242/rc

Data Sharing Statement: Available at https://qims.amegroups.com/article/view/10.21037/qims-24-2242/dss

Funding: This work was supported by CAMS Innovation Fund for Medical Sciences (No. 2021-I2M-1-065); Clinical and Translational Medicine Research Projects of CAMS (No. 2023-I2M-C&T-B-057); National Key R&D Program of China (No. 2022YFC2503400 and No. 2023YFC2412705); National High Level Hospital Clinical Research Funding (No. 2022-GSP-GG-18, 2023-GSP-RC-04, and 2023-GSP-GG-34); and Development Project of National Major Scientific Research Instrument (No. 82327801).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-2242/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by institutional ethics board of Fuwai Hospital (No. 2023-1926) and individual consent for this analysis was waived due to the retrospective nature.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Schleich JM, Rey C, Gewillig M, Bozio A. Spontaneous closure of congenital coronary artery fistulas. Heart 2001;85:E6. [Crossref] [PubMed]
2. Al-Hijji M, El Sabbagh A, El Hajj S, AlKhouli M, El Sabawi B, Cabalka A, Miranda WR, Holmes DR, Rihal CS. Coronary Artery Fistulas: Indications, Techniques, Outcomes, and Complications of Transcatheter Fistula Closure. JACC Cardiovasc Interv 2021;14:1393-406. [Crossref] [PubMed]
3. Taskesen T, Osei K, Hamilton R, Ugwu J, Shivapour D, Tannenbaum M, Ghali M. Coronary Artery Fistulae in Adult: Two Decades of Experience in Clinical Presentation, Angiographic Feature, and Management. Int J Angiol 2021;30:277-84. [Crossref] [PubMed]
4. Yun G, Nam TH, Chun EJ. Coronary Artery Fistulas: Pathophysiology, Imaging Findings, and Management. Radiographics 2018;38:688-703. [Crossref] [PubMed]
5. Lim JJ, Jung JI, Lee BY, Lee HG. Prevalence and types of coronary artery fistulas detected with coronary CT angiography. AJR Am J Roentgenol 2014;203:W237-43. [Crossref] [PubMed]
6. Wei P, Li Y, Zhang F, Xu Z, Xu L, Wan J, Li S, Ouyang W, Wang S, Zhang G, Tse G, Chan JSK, Fang F, Pan X. Transcatheter closure of multiple coronary artery fistulas: a coronary computed tomography angiography-based anatomic classification. Rev Esp Cardiol (Engl Ed) 2025;78:206-17. [Crossref] [PubMed]
7. Kawsara A, Núñez Gil IJ, Alqahtani F, Moreland J, Rihal CS, Alkhouli M. Management of Coronary Artery Aneurysms. JACC Cardiovasc Interv 2018;11:1211-23. [Crossref] [PubMed]
8. Zhu X, Zhou Q, Tong S, Zhou Y. Challenges and strategies in the management of coronary artery aneurysms. Hellenic J Cardiol 2021;62:112-20. [Crossref] [PubMed]
9. Baumgartner H, De Backer J, Babu-Narayan SV, Budts W, Chessa M, Diller GP, Lung B, Kluin J, Lang IM, Meijboom F, Moons P, Mulder BJM, Oechslin E, Roos-Hesselink JW, Schwerzmann M, Sondergaard L, Zeppenfeld K. 2020 ESC Guidelines for the management of adult congenital heart disease. Eur Heart J 2021;42:563-645. [Crossref] [PubMed]
10. Canga Y, Ozcan KS, Emre A, Kul S, Guvenc TS, Durmus G, Kirbas V, Ilhan E, Karatas MB, Oz D, Terzi S, Yesilcimen K. Coronary artery fistula: review of 54 cases from single center experience. Cardiol J 2012;19:278-86. [Crossref] [PubMed]
11. Yuksel S, Yasar E, Nar G, Gulel O, Demircan S, Yilmaz O, Sahin M. Prevalence and characteristics of coronary-cameral communications in adult patients: coronary angiographic analysis of 16,573 patients. Med Princ Pract 2014;23:336-9. [Crossref] [PubMed]
12. Graidis C, Dimitriadis D, Karasavvidis V, Dimitriadis G, Argyropoulou E, Economou F, George D, Antoniou A, Karakostas G. Prevalence and characteristics of coronary artery anomalies in an adult population undergoing multidetector-row computed tomography for the evaluation of coronary artery disease. BMC Cardiovasc Disord 2015;15:112. [Crossref] [PubMed]
13. Zhou K, Kong L, Wang Y, Li S, Song L, Wang Z, Wu W, Chen J, Wang Y, Jin Z. Coronary artery fistula in adults: evaluation with dual-source CT coronary angiography. Br J Radiol 2015;88:20140754. [Crossref] [PubMed]
14. Torres S, Vasconcelos M, Tavares Silva M, Moreira J, Silva JC, Macedo F. Coronary artery fistulas: A 12-year single-center experience. Rev Port Cardiol 2022;41:843-50. [Crossref] [PubMed]
15. Cai R, Ma X, Zhao X, Xu J, Zhu L, Ku L. CTA analysis of 482 cases of coronary artery fistula: A large-scale imaging study. J Card Surg 2022;37:2172-81. [Crossref] [PubMed]
16. Podolec J, Wiewiórka Ł, Siudak Z, Malinowski K, Bartuś K, Dudek D, Żmudka K, Legutko J. Presence and characteristics of coronary artery fistulas among patients undergoing coronary angiography. Kardiol Pol 2019;77:1034-9. [Crossref] [PubMed]
17. Michałowska AM, Skowroński J, Michałowska I, Tyczyński P, Kowalik I, Wolny R, Opolski MP, Demkow M, Hoffman P, Lazarczyk H, Kruk M, Kepka C, Kusmierczyk M, Witkowski A, Pręgowski J. Computed tomographic characteristics of congenital coronary artery fistulas in an adult population. Kardiol Pol 2023;81:1217-26. [Crossref] [PubMed]
18. Li JL, Huang L, Zhu W, Ye WT, Yan LF, Zhong XM, Luo HY, Saboo S, Huang MP, Liang CH. The evaluation of coronary artery-to-pulmonary artery fistula in adulthood on 256-slice CT coronary angiography: Comparison with coronary catheter angiography and transthoracic echocardiography. J Cardiovasc Comput Tomogr 2019;13:75-80. [Crossref] [PubMed]
19. Liemena HA, Atmadikoesoemah CA, Rahimah AF, Sahara E, Kasim M. Coronary artery fistula features associated with clinical symptoms in adults with non coronary artery disease detected with coronary computed tomography angiography. European Heart Journal-Cardiovascular Imaging 2021;22:jeab111.024.
20. Qureshi SA. Coronary arterial fistulas. Orphanet J Rare Dis 2006;1:51. [Crossref] [PubMed]
21. Ouchi K, Sakuma T, Ojiri H. Coronary artery fistula in adults: Incidence and appearance on cardiac computed tomography and comparison of detectability and hemodynamic effects with those on transthoracic echocardiography. J Cardiol 2020;76:593-600. [Crossref] [PubMed]
22. Yakut K, Tokel NK, Varan B, Erdoğan İ, Özkan M. Coronary artery fistulae and treatment in children. Turk J Pediatr 2020;62:614-22. [Crossref] [PubMed]
23. Härle T, Kronberg K, Elsässer A. Coronary artery fistula with myocardial infarction due to steal syndrome. Clin Res Cardiol 2012;101:313-5. [Crossref] [PubMed]
24. Lee SH, Cho JY, Sho HS, Yu CW. Severe Dilated Cardiomyopathy Resulted from a Large Single Coronary Artery Fistula Drained Into the Left Ventricle. Heart Surg Forum 2020;23:E586-9. [Crossref] [PubMed]
25. Vaidya YP, Green GR. Coronary artery fistula. J Card Surg 2019;34:1608-16. [Crossref] [PubMed]
26. Kalisz K, Sanders AE, Avery R, Allen BD. Coronary Artery Fistulas: A Review of the Current and Future Roles of Imaging. J Thorac Imaging 2021;36:333-44. [Crossref] [PubMed]
27. Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, Del Nido P, Fasules JW, Graham TP Jr, Hijazi ZM, Hunt SA, King ME, Landzberg MJ, Miner PD, Radford MJ, Walsh EP, Webb GD. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Develop Guidelines on the Management of Adults With Congenital Heart Disease). Developed in Collaboration With the American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol 2008;52:e143-263. [Crossref] [PubMed]
28. Said SA. Current characteristics of congenital coronary artery fistulas in adults: A decade of global experience. World J Cardiol 2011;3:267-77. [Crossref] [PubMed]
29. Bauer HH, Allmendinger PD, Flaherty J, Owlia D, Rossi MA, Chen C. Congenital coronary arteriovenous fistula: spontaneous rupture and cardiac tamponade. Ann Thorac Surg 1996;62:1521-3. [Crossref] [PubMed]