A computational fluid dynamics study pre- and post-fistula closure in a coronary artery fistula

Outcomes following transcatheter closure or surgical repair of coronary-left ventricular fistula: A single-center study with 10-year experience

BACKGROUND

Coronary arteries drain into the left ventricle, known as coronary-left ventricular fistula (CLVF), an extremely rare anomalous coronary artery disease. Little is known about the outcomes following transcatheter closure (TC) or surgical closure (SC) of CLVF.

METHOD

This was a single-center retrospective study including 42 consecutive patients who underwent either the TC or SC procedure from January 2011 to December 2021. The baseline and anatomic characteristics of the fistulas, procedural outcomes, and late outcomes were summarized and analyzed.

RESULTS

The mean age was 31.6 ± 16.2 years, with 28 male patients (66.7%). Fifteen patients underwent SC group and the remaining received TC group. There were no differences in age, comorbidities, clinical presentations, and anatomic characteristics between the 2 groups. The procedural success rate was similar (93.3% vs. 85.2%, P = 0.639) without operative and in-hospital mortality in both groups. Notably, patients who underwent TC had a significantly shorter postoperative in-hospital length of stay (2.11 ± 1.49 vs. 7.73 ± 2.37 days, P<0.001). The median follow-up time was 4.6 years (2.5-5.7 years, TC group) and 3.98 years (0.42-7.15 years, SC group), respectively. No difference was observed in the incidence of recanalization of the fistula (7.4% vs. 6.7%, P = 1) and myocardial infarction (0% vs. 0%). Cerebral infarction due to discontinuation of anticoagulants happened to two patients in the TC group. Importantly, thrombotic occlusion of the fistulous tract with patent parent coronary artery was found in 7 patients of the TC group.

CONCLUSION

Both transcatheter and SC are safe and effective for patients with CLVF. Thrombotic occlusion is a noteworthy late complication, and its presence indicates the use of anticoagulants lifelong.

A Hemodynamic Analysis of the Thrombosis Within Occluded Coronary Arterial Fistulas With Terminal Aneurysms Using a Blood Stasis Model

Objective: The aim of this study is to numerically evaluate thrombosis risk within occluded coronary arterial fistulas (CAF) with terminal aneurysms, and provide guidance in choosing occlusion positions, with clinical observations as reference. Method: Four patients with CAF were studied, with different occlusion positions in actual treatments. Hemodynamics simulations were conducted, with blood residue predicted using the blood stasis model. Three types of models (untreated model, aneurysm-reserved model and aneurysm-removed model) were studeid for each patient. Four metrics, i.e., proportion of high oscillatory shear index (OSI), area of high OSI, old blood volume fraction (OBVF)) and old blood volume (OBV) was obtained to distinguish the thrombosis risk of different treatments (proximal or distal occlusion), comparing with the follow-up CTA. Results: For all the postopertive models, the high OBVF, high OSI(>0.3) and low time-averaged wall shear stress (TAWSS) regions were mainly at the distal fistula, indicating these regions were prone to thrombosis. The regions where blood residue remains are roughly regions of high OSI, corresponding well with clinical observations. In contrast, TAWSS failed to distinguish the difference in thrombosis risk. Absolute values (area of high OSI, OBV) can better reflect the degree of thrombosis risk between treatment types compared with percentage values (proportion of high OSI, OBVF). By comparing with the actual clinical treatments and observations, the OBV is superior to the area of high OSI in determining treatment type. Conclusion: The OBV, a volumetric parameter for blood stasis, can better account for the CAF thrombosis and reflect the degree of blood stasis compared with OSI or TAWSS, is a more appropriate metric for thrombosis in the fistula. Together with morphological parameters, the OBV could guide clinicians to formulate more appropriate surgical plans, which is of great significance for the preoperative evaluation and treatment prognosis of CAF patients.

Coronary Artery Fistulas: Indications, Techniques, Outcomes, and Complications of Transcatheter Fistula Closure

Coronary artery fistulas (CAFs) are rare coronary anomalies that are usually diagnosed incidentally with cardiac imaging. Small CAFs are generally asymptomatic and can close over time, while some untreated medium or large CAFs can enlarge, leading to clinical sequelae such as cardiac chamber enlargement or myocardial ischemia. With the advancement of transcatheter equipment and techniques, CAFs have been increasingly closed using a percutaneous approach. However, the procedure is not free of limitations given the risk for myocardial infarction, device embolization, and fistula recanalization. In this review, the authors illustrate the contemporary procedural considerations, techniques, and outcomes of transcatheter CAF closure.