Long-term patency of rescue stenting of an anomalous left circumflex coronary artery after transcatheter aortic valve replacement

Abstract

Transcatheter aortic valve replacement (TAVR) in the setting of an anomalous left circumflex coronary artery (LCX) has had a variety of outcomes. Most commonly an anomalous LCX originates as a separate ostium arising from the right coronary sinus or is found branching off of the proximal right coronary artery. The artery courses around the aortic annulus before taking the course seen in typical anatomy. Given this deviation from typical anatomy and increased aortic annulus pressure by the replacement valve, there is an increased risk of a complication such as acute coronary artery occlusion. Special consideration and preparation are needed to prevent adverse outcomes, including death. We report a case in which intraprocedural anomalous LCX rescue stenting proved to be effective for treatment of acute coronary occlusion. Follow-up angiography provided an opportunity to demonstrate long-term patency in rescue stenting during TAVR.

Coronary artery obstruction is a rare but potentially deadly complication of transcatheter aortic valve replacement (TAVR). When performing TAVR in the setting of anomalous coronary arteries, one must carefully consider this deviation from typical anatomy to prevent complications. Our case demonstrates long-term patency of rescue stenting for acute coronary occlusion after TAVR.

CASE PRESENTATION

A 63-year-old woman with no known medical history presented with worsening dyspnea and exertional angina. Physical findings included tachycardia, hypertension, rhonchi, and a systolic murmur radiating to the carotids. The B-type natriuretic peptide was elevated, and troponin I was normal. Electrocardiogram showed sinus tachycardia and left ventricular hypertrophy with repolarization abnormality. Chest x-ray displayed cardiomegaly and pulmonary vascular congestion.

Transthoracic echocardiography showed a normal ejection fraction without wall motion abnormalities, severe aortic stenosis (mean pressure gradient 42.2 mm Hg, aortic valve peak velocity 4.70 m/s, and aortic valve area 0.6 cm²) (Figure 1a), and moderate to severe mitral regurgitation. Computed tomography angiogram measurements were taken for the aortic valve annulus area, left and right sinus of Valsalva diameter, and left and right coronary artery (RCA) height. Based on measurements, there was no concern for ostial coronary occlusion. Coronary angiography showed diffuse disease in the left anterior descending coronary artery (LAD) ranging from 60% stenosis and an anomalous LCX originating from the RCA with a proximal lesion at 80% stenosis. Fractional flow reserve was 0.64 in the LAD, but was not performed on the LCX. Based on the literature, we considered the risk of LCX compromise related to vessel course.

Figure 1.

(a) Transthoracic echocardiography noted severe aortic stenosis and elevated aortic valve peak velocity. (b) A Synergy stent was deployed in the left circumflex coronary artery (LCX) after angiography noted LCX occlusion. (c) Subsequent angiography revealed partial compromise of the LCX distal to the stented area, so another stent was deployed. (d) At 20 months post-TAVR, during catheterization for unstable angina, the LCX showed no significant in-stent restenosis. (e) At 4 years post-TAVR, during stenting of the left anterior descending coronary artery, the LCX showed no significant in-stent restenosis.

After risk stratification and presurgical evaluation, it was determined that the patient would benefit more from TAVR than a surgical approach. Fifteen days before TAVR, the patient underwent percutaneous coronary intervention of the LAD with drug-eluting stents. At this time, intervention to the LCX was deferred. Our reasoning was that a predeployed drug-eluting stent may be compromised by the initial annular pressure from the balloon-expanding valve but may maintain structural integrity if needed intraprocedurally and deployed postimplantation.

Femoral access was obtained for TAVR. Prior to valve positioning, a JR4 guide catheter was used to cannulate the RCA ostium just before the take-off of the anomalous LCX. A Luge wire (Boston Scientific, Marlborough, MA) was passed into the distal RCA. A PT2 wire (Boston Scientific) was used for wiring the anomalous LCX. After predilation, a 2.5 × 24 mm Synergy drug-eluting stent (Boston Scientific) was prepositioned in the LCX to be deployed if there was occlusion after TAVR deployment. A 26 mm Edwards Sapien S3 (Edwards Life Science, Irvine, CA) was deployed under rapid pacing. Postimplantation transesophageal echocardiography showed no significant perivalvular leak, and no postdilation was performed. The LCX was occluded on repeat angiography. The preplaced stent was deployed to 16 atms (Figure 1b). Subsequent angiography revealed partial compromise distal to the stented area, so a 2.5 × 32 mm Promus (Boston Scientific) was deployed to 16 atms (Figure 1c). Subsequent imaging revealed normal flow without luminal compromise.

Although there are reports of rescue stenting for acute coronary occlusion during TAVR, very little is known about long-term patency. Twenty months after TAVR and stenting, our patient was brought back for unstable angina, in which the LCX showed no in-stent restenosis (Figure 1d). A new lesion between her two prior LAD stents was found. Fractional flow reserve revealed non–flow-limiting stenosis. The patient was again brought back for unstable angina 4 years after TAVR and LCX stenting. The previously noted LAD lesion was stented after fractional flow reserve indicated flow-limiting stenosis. The patient’s LCX had no significant in-stent restenosis (Figure 1e).

DISCUSSION

Coronary artery anomalies are rare but well-known cardiac abnormalities. One study of 7115 patients showed anomalous coronary arteries in 0.76% of patients. The most common of these (beyond separate ostia of the LAD and LCX) is an anomalous LCX, observed at 40.74%.¹ The most frequent course of an anomalous LCX arising from the right sinus of Valsalva is retroannular, as in our patient. These LCX anomalies have a variety of ostial anatomy, including origination in the RCA and a separate ostium in the right sinus of Valsalva. These may also present with a slit-like orifice or abnormal take-off, making cannulation and intervention a challenging task.

Various outcomes have occurred during TAVR with an anomalous LCX, ranging from nonocclusion to acute occlusion requiring bailout stenting.^2,3 In one case report, pre-TAVR balloon aortic valvuloplasty was performed to assess for potential occlusion. Compromise was noted and the patient’s management was altered to a surgical approach.⁴ Although rare, acute coronary obstruction after TAVR (0.7% of all cases) can be fatal.⁵ A systematic review described 24 patients with acute coronary artery obstruction after TAVR. Intervention was performed in all but one and was successful in all but two, leading to a mortality rate of 8.3%.⁶ Acute obstruction typically occurs in the procedure lab but may rarely occur hours or days later. Delayed coronary artery obstruction after TAVR has been described in 0.224% of patients and leads to an in-hospital death rate of 50%.⁷ The incidence of coronary artery occlusion during TAVR may be decreased with careful preprocedural anatomic evaluation. In a patient like ours with an 80% proximal anomalous LCX lesion, it is imperative to prepare for complications; in this case, such preparation led to a successful procedure. It is unknown whether pre-TAVR stenting would be sufficiently safe and effective, or if the type of valvular prosthesis chosen might mitigate the risk.

Disclosure statement/Funding

The authors report no funding or conflicts of interest. Patient consent was obtained for publication of this report.