Minimally invasive off-pump coronary surgery via left mini-thoracotomy for a left coronary artery aneurysm in a female: A case report

Abstract

Coronary artery aneurysm is a rare condition commonly treated with conventional surgery under cardiopulmonary bypass because of its complexity. Here, we present a patient who underwent minimally invasive off-pump coronary surgery via left mini-thoracotomy for a left anterior descending artery saccular aneurysm. A Japanese woman in her late 40s, who had been treated with beta-blocker therapy for hypertrophic cardiomyopathy, and steroid and immunosuppressive therapies after renal transplantation, developed chest discomfort on effort recently. Digital Holter electrocardiography showed ST-segment depression associated with exertional dyspnea, suggesting ischemic heart disease. Coronary angiography revealed a saccular aneurysm of the left anterior descending artery that had caused ischemia due to turbulence. This patient was diagnosed with a left coronary artery aneurysm causing ischemic symptoms, which indicated surgical intervention, whereas we judged that the mild to moderate mitral valve regurgitation and mild left ventricular outflow stenosis, caused by hypertrophic cardiomyopathy, did not require surgical interventions. Then, we performed aneurysmal plication after bypass grafting to the left anterior descending by the left internal thoracic artery via left mini-thoracotomy under off-pump guidance. The patient recovered well, and the symptoms disappeared. Postoperative computed tomography angiography showed good patency of the internal thoracic artery and complete disappearance of the aneurysm. This case demonstrates the potential utility of minimally invasive off-pump coronary surgery via left mini-thoracotomy as a useful alternative for patients with simple left coronary artery aneurysms.

Introduction

Coronary artery aneurysms are rare findings, identified in 0.3–12% of patients undergoing coronary angiography, with a markedly lower prevalence in women (0.5%) compared with men (2.2%), and are most commonly detected in the right coronary artery.^1–3 Although interventions are chosen according to the type of aneurysm, surgical interventions via median sternotomy under cardiopulmonary bypass remain the gold standard treatment because of the complexity of aneurysms, including aneurysmal size (giant size) and width (ectasia), fistulas, and bifurcated lesions.^2–4 Therefore, minimally invasive approaches for coronary artery aneurysms are scarce. ⁵ We describe a case of a middle-aged female with a left anterior descending artery (LAD) saccular aneurysm treated with minimally invasive coronary surgery via left mini-thoracotomy under off-pump guidance.

Case report

A Japanese woman in her late 40s developed chest discomfort on effort from October 2024. The patient was followed up by cardiologists at our hospital (Izumiotsu Medical Center, Osaka, Japan) for hypertrophic cardiomyopathy treated with beta-blocker (bisoprolol fumarate 2.5 mg/day) for approximately 20 years. Additionally, the patient had immunosuppressive drugs (mycophenolate mofetil 1000 mg/day and tacrolimus hydrate 4 mg/day) and steroid therapy (prednisolone 5 mg/day) because of renal transplantation for nephrotic renal disease in another university hospital at 20 years of age. Her transplanted kidney had been still functioning with serum creatinine 1.71 mg/dL. The cardiologists performed digital Holter electrocardiography because of the symptoms, which revealed ST-segment depression associated with exertional dyspnea, suggesting ischemic heart disease. Transthoracic echocardiography showed left ventricular hypertrophy without obstructive left ventricular outflow, abnormal wall motion, and mild-to-moderate mitral valve regurgitation due to mitral valve systolic anterior motion. Coronary angiography identified an LAD saccular aneurysm without branches arising from the aneurysm, which was associated with turbulent flow and myocardial ischemia in the LAD without significant stenosis or coronary fistulas (Figure 1). Coronary computed tomography (CT) angiography demonstrated an aneurysm diameter of 18 mm (Figure 2).

Figure 1.

Preoperative coronary angiography. Early (a) and late (b) phase angiography showing a saccular coronary artery aneurysm of the left anterior descending artery with turbulent blood flow.

Figure 2.

Preoperative three-dimensional coronary computed tomography angiography. The white arrow indicates a saccular coronary artery aneurysm of the left anterior descending artery measuring 18 × 17 × 15 mm.

Based on these findings, the patient was diagnosed with ischemic heart disease caused by the LAD saccular aneurysm, and consulted our department. No intervention for the hypertrophic cardiomyopathy was necessary owing to the lack of significant mitral valve regurgitation and left ventricular outflow tract obstruction without any changes of the echocardiographic findings for approximately 10 years, based on the discussion between the cardiac surgeons and the cardiologists. We then considered minimally invasive coronary surgery for the LAD aneurysm because of the high risk of deep sternal wound infection due to immunosuppression and steroid therapies, considering the patient’s wishes.

We performed the surgery under general anesthesia with right differential lung ventilation via left lateral mini-thoracotomy through the fifth intercostal space (7–8 cm skin incision) in January 2025. The skeletonized left internal thoracic artery was harvested using a thoracic scope. Pericardial retraction by suturing to the left mini-thoracotomy wound provided a good exposure of the LAD (Figure 3). After heparinization, we clamped the proximal and distal sides of the LAD artery aneurysm using an elastic tape. Coronary artery bypass grafting to segment 8 by the left internal thoracic artery was performed using a stabilizer (Medtronic, Minneapolis, MN, USA). Finally, we opened, cut, and sutured the LAD aneurysm to narrow the aneurysm with a stenosis of segment 7, followed by achieving hemostasis by releasing the LAD clamp after protamine administration. After surgery, the patient was extubated intraoperatively. Postoperative coronary CT angiography showed good bypass graft patency and no LAD aneurysm (Figure 4). Postoperative transthoracic echocardiography revealed good left ventricular function with no changes in mitral valve regurgitation. Histopathological examination revealed a true aneurysm with slight atherosclerosis, but no inflammatory changes in the wall. The patient was discharged uneventfully on postoperative day 10 and was doing well, with disappearance of ischemic symptoms on effort. Antiplatelet therapy with aspirin 100 mg/day was continued after the operation. Since discharge, the patient has been doing well without any ischemic symptoms for over a year. Although contrast-enhanced imaging was not performed due to the patient’s kidney disease during follow-up, transthoracic echocardiography demonstrated no significant interval changes.

Figure 3.

Intraoperative image. Pericardial retraction (white arrows with a black outline) provided good exposure. The white broken arrow shows the anastomosis of the left internal thoracic artery to segment 8.

Figure 4.

Postoperative three-dimensional coronary computed tomography angiography (a) and coronary computed tomography angiography of the left anterior descending artery (b). The white arrow shows disappearance of the left anterior descending artery saccular aneurysm and a stenosis of segment 7. The white broken arrow indicates good patency of the bypass graft to the left anterior descending artery.

We used the CARE guidelines to draft this manuscript, ⁶ and the CARE reporting checklist when editing, included in Supplemental File A. ⁷ Written informed consent was obtained from the patient for publication of this case report and accompanying images. We have deidentified the patient details.

Discussion

The treatment indications for coronary artery aneurysms remain controversial because of their unclear pathophysiology and small sample sizes. Surgery is often indicated in patients with giant aneurysms (>8 mm) or four times the reference vessel diameter, compression of surrounding organs, or ischemic symptoms caused by thromboembolization.^2,8 We performed surgery in the present case owing to ischemic symptoms caused by delayed flow distal to the aneurysm with turbulence, not thromboembolic events, and the risk of rupture of the saccular aneurysm. Although percutaneous coronary interventions, including covered or non-covered stents with coil embolization, are also considered for saccular aneurysms, we chose surgery because of the patient’s young age, robust good long-term outcomes of surgical interventions for LAD, and the risk of stent-induced complications, including rupture or thrombosis from catheter-based interventions.^2,3

Coronary artery aneurysms are frequently linked to coronary atherosclerosis; over 50% of patients with coronary artery aneurysms present with coronary artery disease, and its severity corelates with the number of aneurysms. ² Congenital anomalies account for 20 to 30% of coronary artery aneurysm cases, while other etiologies include the vasculitis, connective tissue disease, and infectious diseases. ² This patient had no prior history of vasculitis, connective tissue disease, congenital disease, or percutaneous coronary intervention. The histopathological and coronary angiography findings suggest that coronary atherosclerosis contributed to the coronary artery aneurysms, though concurrent immunosuppressive and chronic steroid therapies may have modified the aneurysmal progression.

The optimal surgical technique for coronary artery aneurysm that provides good outcomes is still controversial, and should be tailored to the individual anatomy and presentation because of aneurysmal complexity. ² Generally, aneurysm ligation or resection with bypass grafting, or patch plasty of the coronary artery with or without bypass grafting, are performed.^2,4,9 Singh et al. reported good outcomes of coronary artery bypass grafting with proximal ligation and plication of the aneurysm for LAD aneurysms. ⁹ Additionally, coronary artery bypass grafting to LAD with the left internal thoracic artery has been the gold standard, with good long-term patency and survival rate. ¹⁰ We also performed distal bypass grafting with aneurysmal plication under off-pump guidance, which provided satisfactory results. However, we only performed aneurysmal plication, without the proximal ligation, with a stenosis of the LAD for this patient because the aneurysm did not contain a thrombosis and we wanted to keep the distal access through the native LAD. As for other techniques, interposition grafting with the internal thoracic artery or saphenous vein, or end-to-end reconstruction with aneurysmectomy for isolated aneurysms, have also been reported.^2,11–13 Although aneurysm resection with an interposition grafting can avoid the risks associated with ligation, such as pseudoaneurysmal formation, ¹¹ this technique requires more time owing to anastomosis of the proximal and distal site, compared to bypass grafting. Moreover, a size mismatch between the interposition graft and the coronary arteries may lead to graft failure. ² On the other hand, the end-to-end reconstruction requires a mobilization the coronary vessels. ¹³ For this patient, we did not perform patch plasty, interposition grafting, and end-to-end reconstruction because it was difficult to mobilize the coronary artery under off-pump, and proximal atherosclerosis and small vessel size precluded interposition grafting and patch plasty.

Minimally invasive coronary surgery is an available procedure to prevent sternal wound infection and reduce transfusion volume including cosmetic advantages, although this technique requires a longer operative time compared with conventional surgery. ¹⁴ Previously, minimally invasive direct coronary artery bypass via left mini-thoracotomy for the LAD disease has been performed. ¹⁵ Recently, a multiple coronary artery bypass grafting via left mini-thoracotomy has been adopted with good outcomes.^14,16 Additionally, Babliak et al. has advocated total coronary reconstruction combining other cardiac operations via left anterior mini-thoracotomy under cardiac arrest with cardiopulmonary bypass. ¹⁷ However, there are few reports of minimally invasive off-pump coronary surgery for coronary artery aneurysms. ⁵ For our patient, a left anterior mini-thoracotomy approach under off-pump guidance, as a less invasive technique, was suitable because the patient had a simple LAD saccular aneurysm and was at increased risk of sternal complications due to immunosuppressive and steroid therapy. Moreover, under off-pump guidance via the left mini-thoracotomy, aneurysmal plication or ligation after coronary artery bypass grafting may be safe and reproducible because the initial bypass grafting can maintain the distal flow of the LAD. Recent reports indicate that LAD aneurysms are most often solitary and saccular. ³ Therefore, minimally invasive coronary surgery may be useful for patients with simple coronary artery aneurysms, particularly LAD aneurysms. However, giant aneurysm with thrombosis, aneurysms with fistulas, proximal site coronary aneurysms, or right coronary artery aneurysm would be better treated with other strategies, consisting of the surgeries utilizing cardiopulmonary bypass via median sternotomy or left anterior mini-thoracotomy, because of the required complex maneuvers and techniques.

Conclusion

Minimally invasive off-pump coronary surgery via left mini-thoracotomy may provide satisfactory results for patients with a simple left coronary artery aneurysm. Moreover, the left mini-thoracotomy approach may be useful for patients who have high risks of sternal wound infection.

ORCID iDs

Akimasa Morisaki https://orcid.org/0000-0001-9736-5257

Kokoro Yamane https://orcid.org/0000-0002-0045-2053

Ethical considerations

Our institution does not require ethical approval for reporting individual cases or case series.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Data Availability Statement

Details of this case report are available within the article.*