Abstract
Minimally invasive coronary artery bypass grafting (MICS CABG) offers smaller incisions, faster recovery, and less risk of mediastinitis. 1 However, it is technically challenging, especially for proximal anastomosis in patients with a calcified ascending aorta. Partial clamping increases the risk of stroke and aortic injury. The HeartString III (Getinge AB, Göteborg, Sweden) allows clampless proximal anastomosis and is widely used in standard CABG, but reports of its use in MICS CABG via a small thoracotomy are limited. We describe our technique using HeartString III through the right second intercostal space (ICS) in a patient with severe aortic calcification.
Following induction general anesthesia and intubation with a double-lumen tube for single-lung ventilation, the patient was positioned in the right semidecubitus position at approximately 30°. An 8 cm left thoracotomy was performed at the fifth ICS, and a ThoraTrak retractor (Medtronic, Galway, Ireland) was inserted and gently retracted in the cephalad and leftward directions. Bilateral internal thoracic arteries were harvested in a skeletonized fashion using a long-shaft harmonic scalpel (Ethicon Endo-Surgery Inc., Cincinnati, OH, USA). These procedures were performed under single-lung ventilation of the right lung.
After harvesting all grafts, a 5 cm incision was made in the second or third right anterior ICS, planned preoperatively based on the computed tomography (CT) scan (Supplemental Fig. 1a, Supplemental Fig. 2a-b). The right lung was deflated, and ventilation was switched to the left lung, bringing the ascending aorta closer to the right thoracic incision (Supplemental Fig. 1b). The pericardium around the aorta was opened, and a traction suture was placed to draw the ascending aorta closer to the incision (Fig. 1c). An XXS-sized wound retractor (Applied Medical, Rancho Santa Margarita, CA, USA) was inserted into the pericardial cavity, significantly reducing the distance between the incision and the ascending aorta. This technique provided optimal exposure for performing the proximal anastomosis (Supplemental Fig. 1d, Supplemental Fig. 2c).
The HeartString III proximal seal system was inserted into the ascending aorta, followed by proximal anastomosis of the saphenous vein graft (SVG) using a running 6-0 polypropylene suture in an end-to-side fashion (Supplemental Fig. 2d, Supplemental Video). After completion of the proximal anastomosis, ventilation was switched to the right lung, and all distal anastomoses were performed in the standard manner.
Case 1
A 63-year-old man with coronary artery disease (CAD), diabetes mellitus (DM), and hemodialysis was referred to our hospital. CT showed calcification of the ascending aorta. Coronary angiography (CAG) showed severe stenosis in the proximal right coronary artery and posterior descending artery (PDA), proximal and mid–left anterior descending artery (LAD), high lateral branch (HL), obtuse marginal branch (OM), and posterolateral branches (PL). MICS CABG × 5 was performed with the following graft configuration: left internal thoracic artery (LITA)–LAD, right ITA (RITA) with SVG (I-composite) sequentially to the OM and HL, and SVG from the ascending aorta sequentially to the PDA and PL. Intraoperative transit-time flow measurements (TTFMs) were 44 mL/min for LITA–LAD, 36 mL/min for RITA with SVG–OM–HL, and 58 mL/min for aorta-SVG–PDA–PL.
Case 2
A 64-year-old man with angina pectoris and DM was referred to our hospital. CT showed atheromatous changes in the ascending aorta, and CAG revealed severe stenosis in the PDA, LAD, and PL branches. MICS CABG × 3 was performed with the following graft configuration: RITA–LAD, LITA–PL, and SVG from the ascending aorta to the PDA. Intraoperative TTFMs were 25 mL/min for RITA–LAD, 15 mL/min for LITA–PL, and 30 mL/min for aorta–SVG–PDA.
Case 3
A 69-year-old man with CAD, DM, and hemodialysis presented to our hospital. CAG revealed severe stenosis in the LAD, PL, and PDA. CT showed calcification of the ascending aorta and severe stenosis of the left subclavian artery (Supplemental Fig. 2a). Therefore, the LITA was used as a free graft rather than in situ. MICS CABG × 3 was performed with the following graft configuration: RITA–LAD and SVG from the ascending aorta with free LITA (V-graft) to the PDA and PL. Intraoperative TTFMs were 28 mL/min for RITA–LAD, 16 mL/min for SVG–PDA, and 44 mL/min for free LITA–PL.
We used this technique for 3 patients in MICS CABG. All patients were discharged uneventfully, and all grafts were patent. This technique allows proximal anastomosis without partial clamping of the ascending aorta, thereby reducing the risk of stroke and aortic dissection. We have not experienced any complications related to this technique.
MICS CABG is considered an effective procedure due to its minimally invasive nature. However, technical challenges remain, particularly for proximal anastomosis in patients with a calcified or diseased ascending aorta. Aubin et al. reported an additional right-sided upper “half-mini-thoracotomy” for aortocoronary bypass in MICS CABG, 2 and Sakai et al. subsequently refined this technique. 3 This modified technique brings the ascending aorta closer to the skin incision and provides excellent surgical exposure, facilitating the use of the HeartString III device and the performance of proximal anastomosis. Using the HeartString device via the left thoracotomy made right-angle insertion technically difficult and increased the risk of aortic injury.
Preoperatively, the optimal ICS should be determined based on 3-dimensional CT imaging, and the second or third ICS is most commonly used. Furthermore, evaluating the condition of the ascending aorta is crucial. Preoperative CT and intraoperative epiaortic echocardiography are essential for determining the optimal anastomosis site. Because there is a possibility of bleeding or aortic dissection related to this technique, preparation for median sternotomy and cardiopulmonary bypass should be made.
An aorta no-touch strategy is commonly adopted in MICS CABG, but proximal anastomosis to the ascending aorta is sometimes necessary to secure adequate inflow. This technique reduces the risk of embolism and expands the indications for MICS CABG in patients with a diseased ascending aorta.
Footnotes
Acknowledgements
We appreciate Ako Takusagawa for medical support, Sachika Izena for illustration, and Yuki Moriuchi for total assistance.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethics Statement
Institutional Review Board approval was not required, and informed consent for publication was obtained from the patients.
Supplemental Material
Supplemental material for this article is available online.