Minimally Invasive Approach versus Sternotomy for Bentall Procedure: A Single-Center Experience

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Introduction
Te trend toward minimally invasive surgery is becoming increasingly evident in various surgical felds.Cardiac surgeons have also been exploring minimally invasive procedures in patients with heart disease.Currently, the use of minimally invasive cardiac surgery is growing [1], and various minimally invasive surgical procedures have emerged in an endless stream, including minimally invasive aortic valve surgery, mitral valve surgery, and congenital heart disease surgery [2][3][4][5].Te Bentall procedure is a classic procedure for treating ascending aorta/aortic root aneurysms complicated by aortic valve disease [6], and the need for minimally invasive procedures continues to increase.
At present, a small number of centers have reported the minimally invasive Bentall procedure, which uses a small incision in the upper sternum as the surgical approach [7][8][9].Tis difers from the approach used for the minimally invasive Bentall procedure at our center.Based on our experience with our minimally invasive aortic valve replacement procedure, we chose a small incision on the right anterior chest as the preferred approach [2].Tis minimally invasive Bentall procedure has shown advantages in some patients [10].Nonetheless, the safety and efcacy of minimally invasive Bentall procedures remain controversial due to the lack of evidence from controlled studies on sternotomy Bentall procedures.Terefore, we retrospectively analyzed the clinical data of 56 patients who underwent minimally invasive Bentall procedures and sternotomies performed by the same surgical team at our center.Te safety and feasibility of minimally invasive Bentall surgery were explored by comparing intraoperative and postoperative clinical data with postoperative follow-up data.

Study Participants.
A total of 56 patients who underwent the Bentall procedure done by the same surgical team in our center between December 2018 and December 2021 were selected as the research subjects.Inclusion criteria were (1) ascending aortic dilatation >5 cm with aortic valve disease, (2) Marfan syndrome, and (3) Debakey type II aortic dissection combined with aortic valve insufciency that cannot be repaired.Exclusion criteria included (1) femoral artery plaques, (2) pulmonary insufciency, (3) patients with aortic dissection within 3 days of onset, and (4) emergency surgery.Based on the surgical approach, the patients were divided into a right anterior chest minimally invasive Bentall procedure group (RAT-Bentall group) and a conventional median thoracotomy Bentall procedure group (C-Bentall group).Tere were 10 males and 3 females in the RAT-Bentall group, ranging in age from 24 to 67 years old, with an average of 55.31 ± 11.42 years old.Tere were 33 males and 10 females in the C-Bentall group, ranging in age from 26 to 76 years old, with an average of 55.35 ± 12.74 years old.Tere were no signifcant diferences in the general data between the two groups (P > 0.05).Te preoperative data of the patients in the two groups are shown in Table 1.

RAT-Bentall.
Te patient was placed in a supine position under general anesthesia with a single-lumen endotracheal tube.Te defbrillation electrodes were placed behind the right scapula and in the ffth intercostal space on the front line of the left axilla.After disinfection, the surgical area was covered with sterile surgical towel.In the groin area (usually on the right side), the skin and subcutaneous tissue were incised to expose the femoral artery and vein.Heparinized femoral artery and vein cannulas were used to establish peripheral CPB access.Right anterior parasternal incision was selected (select the second or third intercostal space according to the preoperative CT), and the skin, subcutaneous tissue, and muscle layer were incised.Initiation of CPB was done, and patient temperatures were lowered.Te pericardium was incised longitudinally, 2-3 stitches were sutured on the left and right sides to suspend the pericardium, and an incision protection sleeve (Figure 1(a)) was placed to expose the aortic root and heart (Figures 1(b) and 1(c)).Te ascending aorta was blocked using Chiwood-blocking forceps (Figure 1(d)).Te aorta was incised, and myocardial protection solution was perfused through the left and right coronary arteries.One suture was placed at the valve commissure for suspension (three sutures in total; Figure 1(e)), and the diseased aortic valve was resected (Figure 1(f )).Te aortic valve and vascular graft (or series aortic valve graft) were implanted, and the proximal ends of the valve and vascular graft were anastomosed.It should be noted that when performing distal anastomosis, the vascular graft should frst be cut to the appropriate length.Te recommended order of anastomosis is to frst anastomose the posterior wall of the blood vessel and then the anterior wall of the blood vessel, starting from the proximal end to ending at the distal end.Te proximal anastomosis sequence was frst from 4 o'clock to 7 o'clock (suturing in a clockwise direction), then from 7 o'clock to 10 o'clock (suturing in a clockwise direction), and fnally from 4 o'clock to 10 o'clock (suturing in a counterclockwise direction).Anastomotic bleeding can be reinforced by continuous and intermittent sensations.A 5-0 Prolene ™ line was used to transplant the left and right coronary arteries to the corresponding vascular graft, and direct intraluminal anastomosis was performed.A 4-0 Prolene ™ wire was used to anastomose the graft to the distal end of the ascending aorta (Figure 1(g)).Te aortic root was wrapped with an autologous aortic wall, and a right atrial shunt was created (Figure 1(h)).Te heart was then allowed to expel gas, and the blocking forceps were opened to facilitate circulation.Te heart was returned to its normal rhythm, and the body temperature was then allowed to recover.Each cannula was removed after waiting for the circulation to stabilize.Protamine was used to neutralize heparin.Te pericardial cavity was checked for active bleeding, and a chest drain was placed.Te chest was then sutured layer-by-layer after checking the instruments and gauze.

C-Bentall. Te conventional median thoracotomy-
Bentall procedure adopts the standard median thoracotomy approach.A median longitudinal split of the sternum was selected followed by the Bentall procedure.For postoperative pain management, the patients in both groups used intravenous opioid pumps provided by the anesthesiology department.

Data Collection.
Intraoperative variables included the duration of cardiopulmonary bypass (CPB), duration of aortic occlusion, duration of surgery, and occurrence of sternotomy conversion.Postoperative variables included ventilator assistance time, days of hospital stay in the intensive care unit (CSICU), postoperative 24 hour drainage volume, postoperative 24 hour blood transfusion rate, reoperation rate for hemostasis, days of postoperative hospital stay, visual analog scale (VAS) pain score (VAS pain score was assessed 24 h after the patient walked up), and the probability of complications.Te postoperative complications included atrial fbrillation, stroke, pleural efusion, renal insufciency, poor wound healing, and in-hospital mortality.Six months after the patient was discharged from hospital, outpatient reviews and telephone interviews were conducted.Follow-ups included echocardiography and all-cause mortality.

Statistical Analysis.
Statistical analyses were performed using SPSS 23.0.Independent sample t-test analysis was used to compare enumeration data such as operation time, CPB time, aortic cross-clamp time, CSICU stay time, ventilator-assisted time, drainage during the frst 24 hours, VAS pain score, days of postoperative hospital stay, and echocardiographic data at the 6-month follow-up.Chisquare tests were used to analyze quantitative data such as the blood transfusion rate in the frst 24 h, reoperation rate 2 Journal of Interventional Cardiology for hemostasis, postoperative complication rates, and mortality.Diferences were considered statistically signifcant at P < 0.05.2).

Comparison of Follow-Up Data 6 months after Discharge.
Patients were followed up for 6 months after discharge through outpatient reviews and telephone interviews.A total of 53 of the 56 patients were followed up, including one patient who died in the RAT-Bentall group (the cause of death was sudden acute severe pancreatitis).Te 3 patients who were lost to follow-up were all in the C-Bentall group.Tese 3 patients did not visit the outpatient clinic for reexamination and could not be contacted.Scarring in the patient who underwent the RAT-Bentall procedure was less visible 6 months after discharge (Figure 2).Te 52 patients who were followed up were examined using echocardiography.No statistical signifcance was found in the ejection fraction or other echocardiographic indicators between the two groups (Table 3).

Discussion
Alleviating patient pain and accelerating postoperative recovery are the goals of surgeons.We performed the RAT-Bentall procedure in the hope that patients would have fewer surgical complications and faster recovery.In the RAT-Bentall procedure performed at our center, all patients recovered and were discharged from the hospital.Compared to the C-Bentall procedure, there was no increased risk of complications, postoperative pain was reduced, and both CSICU and postoperative hospital stays were shorter.Terefore, in which types of patients is RAT-Bentall appropriate?Te experience at our center is that as long as there are no contraindications, the RAT-Bentall procedure can be selected.Contraindications to the RAT-Bentall procedure include the presence of a signifcant femoral plaque that hinders peripheral CPB techniques or severe thoracic deformity that holds back surgical manipulation from the intercostal space.In the real world, our strategy for deciding who gets the RAT-Bentall and who gets the C-Bentall is "Patient choice takes precedence over surgeon driven."Te patient will be fully informed of both surgical options.When both methods are available, it is up to the patient to decide which surgical method to use.However, when some patients are unsuitable for RAT-Bentall, we recommend that they choose the C-Bentall instead of the RAT-Bentall.
Terefore, it is important to select the RAT-Bentall incision approach using preoperative CT scans.Te incision selection for the RAT-Bentall is the same as that for the aortic valve we made previously, which is the right anterior thoracic intercostal incision [2].Te choice of incision requires the aorta to be located on the right and generally more than 1/2 of the sternum [11,12].Te incision protection sleeve was placed in the pericardial position to obtain a better surgical view (Figures 1(a) and 1(b)).Te appropriate intercostal space was selected through threedimensional reconstruction of the preoperative chest CT scan.Selection was based on the intercostal space that was more parallel to the right pulmonary In most cases, the second intercostal space was and some were placed in third intercostal space.Another important point is that when performing preoperative CT, the patient is required to follow the surgical position, not to raise his hands above his head but to place his hands naturally on his side.Te CT results obtained in this manner were more consistent with the position at the time of surgery.To avoid damaging the right internal mammary artery, the skin was incised approximately 1.0 cm away from the right border of the sternum.Te main risks associated with the Bentall procedure are coronary ischemia and proximal anastomotic bleeding [13].In our Bentall procedure, the experience with coronary ostium anastomosis is that coronary ostium release must be performed to achieve a tension-free anastomosis.When suturing the vascular graft, the recommended order of anastomosis is to frst anastomose the posterior wall of the blood vessel and then the anterior wall of the blood vessel, starting from the proximal end and ending at the distal end.After the vascular graft opened the channel through a coronary opening, we adopt the method of directly anastomosing the opening of the coronary artery.Care must be taken when stitching and tying knots to not overstretch the thread.Tis is done to prevent the blood vessel wall from tearing and bleeding and to prevent the coronary arteries from twisting and stretching, causing ischemia.One strategy to prevent proximal anastomotic bleeding is to perform right atrial shunt.Te right atrial shunt is an efective method of preventing bleeding with good results over the years [14,15].
Prolonged CPB can have potentially detrimental efects on patient outcomes [16].In this study, the CPB and aortic cross-clamp times in the RAT-Bentall group were slightly longer than those in the C-Bentall group; however, the diference was not statistically signifcant.Tis is because the incision of the RAT-Bentall surgery is small; therefore, the  operation space is reduced, and the operation difculty is increased.However, the operative time in the RAT-Bentall group in this study was very similar to that in the C-Bentall group.Tis is because, although the RAT-Bentall group prolongs the time for major surgical operations, it the time required to close the for hemostasis, the overall operation time is not much diferent from that of the C-Bentall group or even shorter.
Patients typically require a transfer to the CSICU for monitoring and treatment after cardiac surgery.Studies have shown that prolonged use of ventilators after surgery is associated with increased pulmonary complications, length of CSICU stay, and length of hospital stay [17].In this study, the ventilator assistance times of the two groups were comparable, and the average ventilator assistance time of the RAT-Bentall group was shorter than that of the C-Bentall group; however, the diference was not statistically signifcant.It can be seen that the RAT-Bentall group does not prolong the duration of ventilator assistance.Appropriate postoperative analgesia is essential for fast recovery of patients [18].Postoperative pain management in the two groups was the same at our center; we will provide patients with analgesia pumps after surgery and remove them when the VAS pain score decreases.Te study found that the pain scores of patients in the RAT-Bentall group were signifcantly lower than those in the C-Bentall group.Tis indicates that the RAT-Bentall procedure can reduce postoperative pain.Minimally invasive cardiac surgery is as safe as traditional surgery and can reduce hospital costs due to shorter CSICU stay [19].Te durations of CSICU stay and postoperative stay in the RAT-Bentall group were shorter than those in the C-Bentall group.Te RAT-Bentall procedure allowed the patients to recover more quickly.In this study, there was no statistically signifcant diference in the incidence of postoperative complications between the two groups, which may be related to the small sample size.However, the RAT-Bentall procedure does not result in many complications.Terefore, a comparison of complications requires multicenter studies with large sample sizes to determine the advantages.
Tis study had the inherent limitations of a retrospective study design, single-center design, and short follow-up period.Te small number of patients who underwent the RAT-Bentall procedure indicates a potential weakness in the results.

Conclusion
Te RAT-Bentall method is safe.Compared with the C-Bentall procedure, it can reduce postoperative pain and patients' CSICU and postoperative hospital stay.Based on our center's experience, certain conditions must be met to conduct a RAT-Bentall procedure.First, regardless of the surgical procedure, suitable surgical instruments are essential, and there must be suitable cardiac surgical instruments for the RAT-Bentall procedure.For example, we used long-shafted instruments to assist in suturing and knot pushers to assist in tying knots.Second, reasonable team cooperation is essential; therefore, a skilled minimally invasive cardiac surgery team is required.Finally, the chief surgeon must have profcient minimally invasive surgical skills (for example, have mastered minimally invasive aortic valve replacement frst) and excellent vascular anastomosis techniques.With its benefts in safety and patient outcomes, the RAT-Bentall procedure is worthy of further promotion.

Figure 1 :
Figure 1: Te RAT-Bentall procedure.(a) Te incision protection sleeve we use in RAT-Bentall surgery.(b) and (c) Te pericardium was incised longitudinally on the left side, 2-3 stitches were sutured on the left and right sides to suspend the pericardium, and then an incision protection sleeve was placed to expose the aortic root and the heart.(d) Te ascending aorta was blocked using Chiwood blocking forceps.(e) One suture was sutured at the valve commissure for suspension, 3 sutures in total.(f ) Resection of the diseased aortic valve.(g) Anastomose the graft of the ascending aorta.(h) Te aortic root was wrapped with an autologous aortic wall, and right atrial shunt was performed.

Figure 2 :
Figure 2: Te scarring of the patient who underwent the RAT-Bentall procedure was less visible 6 months after discharge.
BMI, body mass index; LVEF, left ventricular ejection fraction; LVEDD, left ventricular end-diastolic diameter; LVEDS, left ventricular end-systolic diameter; AF, atrial fbrillation; RAT-Bentall, right anterior chest minimally invasive; Bentall, conventional sternotomy.Values were expressed as the mean ± SD, n (%), or n1/n2.Journal of Interventional Cardiology 3 3.2.Comparison of Postoperative Data.In the RAT-Bentall group, the CSICU stay time was 1.90 ± 0.52 d; the ventilator assisted time was 20.23 ± 6.85 h; the drainage of frst 24 h was 303.00 ± 431.42 ml; 8 cases were transfused within the 24 with a transfusion rate of 61.5%; pain was 3.00 ± 2.08 points; the days of postoperative hospital stay was 7.62 ± 1.81 days; 0 cases of reoperation for hemostasis, 2 cases of postoperative pleural efusion, 2 cases of new-onset atrial fbrillation, 1 case of renal insufciency, no postoperative stroke, poor incision healing, and deaths.In the C-Bentall group, the CSICU stay time was 2.51 ± 1.

Table 2 :
Intraoperative and postoperative data characteristics.

Table 3 :
Patient echocardiographic data 6 months after discharge.