Transcatheter aortic valve implantation in patients with anomalous origin of a coronary artery

1 INTRODUCTION

Transcatheter aortic valve implantation (TAVI) has become an established treatment option for severe aortic valve stenosis in elderly patients across all surgical risk categories. Preprocedural planning including coronary angiography and multi-detector computed tomography (MDCT) is widely adopted. Within the scope of this diagnostic work-up, coronary artery anomalies (CAA) are in most cases a rare incidental finding. Since CAA are infrequent per se, management of those patients with concomitant aortic stenosis is only derived from a few case reports. However, this clinical entity requires careful attention as it might be associated with an elevated risk of peri-interventional coronary obstruction.

We therefore performed a literature search on existing reports and added a case series from our institution hereby providing the largest available analysis on CAA in patients undergoing TAVI. We sought to address uncertainties concerning preprocedural planning and to highlight potential pitfalls described in the collected cases. A better understanding of this rare scenario may help the operator to decide whether preventive measures must be implemented to optimize procedural safety and success when encountering patients with this unique anatomic feature.

2 METHODS

We performed a systematic literature search in PubMed and Google Scholar for reports published on CAA in patients undergoing TAVI between 2011 and 2022. The following search terms were used: transcatheter aortic valve replacement, TAVI, coronary artery anomaly, coronary obstruction, anomalous coronary artery. After having identified relevant articles, we used those papers as “start set” for further research by using their reference list or the citations to identify more relevant articles. This method is referred to as backward respectively forward snowballing.

In 2011, Weich et al. described for the first time a successful TAVI in a patient with malignant anomalous origin of the right coronary artery.¹ Between 2011 and 2022, 17 publications including a total of 20 patients who had CAA and underwent TAVI were identified.^1-17 Each publication was analyzed regarding CAA type and course of the anomalous coronary artery, procedural characteristics including the choice of the transcatheter heart valve (THV), whether coronary protection was used or not and if coronary obstruction did ultimately occur after TAVI.

In addition, we screened our institutional database and retrospectively identified 20 consecutive patients with CAA treated by TAVI between 2016 and 2022. Patient and procedural data were prospectively collected and entered into a dedicated institutional database as part of the Leipzig TAVI registry (NCT05015452). Manifestation of CAA by MDCT was documented separately. CAA was classified as previously described by Angelini et al.¹⁸ The principal clinical endpoint of interest was the occurrence of coronary obstruction.

3 RESULTS

Patient data from the published experience and our local institution are presented in Tables 1 and 2. There were 20 cases of CAA through literature research and 20 cases in the institutional database identified; 50% of patients were male and the pooled mean age was 80.6 ± 7.3 years. The most common CAA in the total cohort was anomalous origin of a coronary artery from the opposite sinus (ACAOS) (75%, 30/40). Of these 30 patients with ACAOS, 17 had the left circumflex coronary artery, 3 the left anterior descending and 4 the left main coronary artery originating from an opposite sinus. In 6 cases the right coronary artery originated from the left coronary sinus. Seven cases of a single coronary artery were included. A retro-aortic course was present in 22 cases and an interarterial trajectory in 13 cases. CAA detected in the majority of the cases presented here are shown in Figure 1.

Coronary protection by vessel wiring was performed in 11 cases. Periinterventional coronary obstruction occurred in 5 (12.5%) patients. In those cases, the trajectory of the anomalous artery was retro-aortic in three and interarterial in two patients. Protective measures had been taken in four of these patients. Coronary obstruction occurred after the use of balloon-expandable THV in two cases, a mechanically-expanding and a self-expanding THV in one case respectively and after balloon aortic valvuloplasty (BAV). Management of coronary obstruction included coronary stent placement in three cases, transient extracorporeal life support in one case and emergency coronary artery bypass grafting in another case. TAVI was aborted in one case. There was no procedural mortality. In consideration of the small case number, we did not perform a formal statistical analysis. However, the patient and procedural characteristics are grossly comparable between the published and the local institutional series. The main difference between the two cohorts was the frequency of coronary protection and obstruction. Protective measures were taken in 45% of the cases found in the published experience versus 10% in our local cohort. All cases of coronary obstruction occurred in the published cohort.

4 DISCUSSION

CAA are a rare congenital condition comprising an ample number of anatomic variations affecting the origin and course of the coronary arteries. An extensive classification has been proposed elsewhere.¹⁸ The prevalence of CAA was historically studied in coronary angiography populations and autopsied patients, but MDCT has proven to be a valid tool to visualize these anomalies as well.¹⁹ Although the exact prevalence remains unclear, it is estimated to range between 0.2 and 2.3% in the general population.²⁰

Some CAA may cause life-threatening symptoms and severe myocardial ischemia leading to sudden cardiac death.²¹ Patients with ACAOS with certain high-risk anatomical features such as an interarterial course (between the pulmonary artery and the aortic root), slit-like coronary ostium and intramural course are especially prone to myocardial ischemia.²⁰ Higher rates of sudden cardiac death are found for anomalous left coronary arteries compared to anomalous right coronary arteries.^{22, 23} A rare entity associated with higher risk of sudden cardiac death are single coronary artery origins supplying the right coronary artery, the left anterior descending and circumflex artery.²⁰

In contrast to the interarterial trajectory, the retro-aortic course is considered to be less malignant and often found when the left circumflex artery originates from the right coronary artery or from the right sinus of Valsalva.²⁴

4.4 Management of TAVI in CAA patients

Early detection of coronary obstruction during the intervention is of great importance. In addition to continuous hemodynamic and electrocardiographic monitoring, the authors of some cases described selective angiography or repeated aortic root injections during implantation. The use of intravascular ultrasound may confirm vessel compression.¹⁵

A strategy to identify possible coronary artery occlusion before TAVI is the utilization of BAV as described by Tabachnick et al.⁹ In this case, BAV was done in a patient with a retro-aortic course of an anomalous LCx, which led to compression of the vessel during balloon inflation. Subsequently, the authors refrained from performing TAVI. Such an approach may be a proof of concept but leaves the patient with an untreated condition and most patients in this situation are not eligible for surgical valve replacement.

In cases of elevated risk of coronary obstruction some authors opted to implement precautions to increase peri-interventional safety. The most common measure taken was to protect the coronary artery at risk with a 0.014 inch wire for rapid re-access after THV implantation.^{4, 5, 7, 9, 11, 12, 15-17} A guide catheter extension catheter was placed over the wire to disengage the larger coronary guide catheter during valve deployment in one case.¹² Provisional balloon or stent placement was performed in five cases.^{7, 11, 12, 17} Coronary stent implantation was necessary in three of those cases and was performed without difficulty.^{5, 7, 15} In all other cases when post implantation angiography showed sufficient coronary flow, the wire and/or balloon and stents were successfully removed from the coronary artery. Nevertheless, cannulation of the anomalous ostium can be challenging, and emergency bypass graft surgery may be a bail out strategy to restore coronary flow.¹³

Recently, increasing interest has been developed concerning the possible benefits of commissural alignment of transcatheter aortic valves.²⁸ However, in patients with CAA, commissural alignment might even be counterproductive. Costa et al. described a case in which they intentionally misaligned the neo-commissures to prevent potential impairment of coronary reaccess.¹⁷

Finally, careful attention should be given to bioprosthetic valve oversizing and high-pressure balloon inflation because it intuitively increases the risk for coronary compression.⁵ An algorithm for the management of patients with CAA undergoing TAVI is proposed in (Figure 2).

5 LIMITATIONS

We did not perform formal statistical analysis in view of the small number of reported patients with CAA treated with TAVI. Hence, the proposed mechanistic explanations and highlighted risk factors for coronary obstruction in this particular scenario are merely hypothesis-generating. Although we present a consecutive series of patients from our institution, the findings from the published experience may underlie a certain selection bias. Underreporting of procedural complications and unsuccessful interventions may contribute to this fact and ultimately obscure the overall incidence of coronary obstruction in patients with CAA. The proposed algorithm for the management of patients with CAA has been derived from the published reports and our own experience. External validation in a broader cohort is needed.

6 CONCLUSION

With a total of 40 cases, this is the largest body of evidence of patients diagnosed with aortic stenosis and CAA undergoing TAVI. Little is known about feasibility of TAVI in patients with CAA. In the absence of evidence-based clinical practice guidelines, a patient-tailored and risk-adapted approach is recommended. Awareness of this clinical scenario and meticulous preprocedural assessment together with protective measures could help minimize procedural complications.

CONFLICTS OF INTEREST STATEMENT

Steffen Desch reports that his hospital received speakers' honoraria and/or consulting fees on his behalf from Medtronic. Mohamed Abdel-Wahab reports that his hospital received speakers' honoraria and/or consulting fees on his behalf from Medtronic and Boston Scientific. The remaining authors declare no conflict of interest.