Health-Related Quality of Life following Minimally Invasive Totally Thoracoscopic Mitral Valve Surgery


 Background

In order to compare the impact of two different approaches to mitral valve surgery on health-related quality of life, we conducted a retrospective study comparing minimally invasive totally thoracoscopic mitral valve surgery with median sternotomy mitral valve surgery.
Methods

A total of 163 patients who underwent mitral valve surgery at our institution between January 1, 2019 and December 31, 2019 were enrolled. In 163 patients, mitral valve surgery was performed using either totally thoracoscopic approach (TA n = 78) or median sternotomy approach (SA n = 85). We used the Scar Cosmesis Assessment and Rating Scale and the Numerical Rating Scale to measure the pain intensity and the aesthetic appearance of surgical incision and used the MOS SF-36 to assess the HRQoL.
Results

The two groups of patients were similar in terms of demographic, echocardiography data and postoperative complications. The pain intensity and aesthetic appearance of the totally thoracoscopic approach were significantly better than that of the median sternotomy approach. Significant differences in the subscale of the SF-36 were found between the two groups.
Conclusions

When compared to the median sternotomy mitral valve surgery, totally thoracoscopic mitral valve surgery has an equally good outcome, while improving aesthetic appearance and reducing pain intensity. Our study suggested that totally thoracoscopic approach is superior to median sternotomy approach in terms of pain intensity, aesthetic appearance and HRQoL.


Introduction
Minimally invasive mitral valve surgery (MIMVS) has been in clinical practice since Cosgrove 1 and Cohn 2 performed the rst minimally invasive valve surgery in 1996, and subsequently Carpentier 3

and
Chitwood 4 performed the video assisted mitral valve surgery. In China, with the advancements in technology and the signi cant risen demand from patients, more and more centers are opting for minimally invasive approaches to mitral valve repair and replacement. In recent years, totally thoracoscopic approach has become a common and safe technique for mitral valve surgery in our institution. The improvement in relevant surgical techniques provides the same mortality and morbidity rates as the median sternotomy approach [5][6] . We performed a literature retrieval and found that fewer studies focus on totally thoracoscopic mitral valve surgery regarding pain intensity, cosmetic appearance and HRQoL have been conducted. Therefore, we enrolled 163 patients who had undergone mitral valve surgery using either totally thoracoscopic approach or median sternotomy approach at our institution and compared the HRQoL and the aesthetic appearance of surgical incision and the pain intensity of these patients.

Materials And Methods
Patient Selection and Data collection A total of 163 consecutive patients who underwent mitral valve surgery (78 patients with totally thoracoscopic approach and 85 patients with median sternotomy approach) at our institution from January 1, 2019 to December 31, 2019 were enrolled. All patients either returned to the outpatient department for follow-up visits or were contacted by cellphone to con rm all data collected. All patients had been follow-up and all data were available in the patient pro les. All participants were requested to complete the relevant questionnaires in different ways.
It was a retrospective study that enrolled 163 patients and reported severe events according to the guidelines for reporting mortality and morbidity after cardiac valve interventions published in 2008 7 . The inclusion and exclusion criteria were discussed and mainly refer to the expert opinion 8 . The inclusion criteria included the following: (1) primary mitral valve disease; (2) prior right thoracic surgery; (3) no hearing disorders; (4) complete a whole-course follow-up. The exclusion criteria included the following: (1) inability to complete routine examination; (2) unable to nish the questionnaires; (3) signi cant peripheral vascular disease; (4) Severe cardiac insu ciency; (5) Severe pectus excavatum and kyphoscoliosis; (6) additional aortic valve regurgitation and coronary artery disease requiring surgical interventions.
Surgical Technique 1. Anesthesia and surgical preparation.
The anesthesia protocols for the two different approaches to mitral valve surgery were generally almost the same, but the minimally invasive approach relied more on perfusion and anesthesia techniques. We preferred to have patients intubated with a double-lumen endotracheal tube or a single-lumen endotracheal tube with bronchial blocker, for the purpose of de ating the right lung during surgery. Transesophageal echocardiography (TEE) was of great importance for participation in cannulation and cannula placement. A radial or a brachial arterial pressure monitoring was su cient. A Non-invasive nger pulse oximeter was placed in the right arm to monitor the oxygen saturation.
The patient with such a right minimally thoracotomy was placed in a supine position, with a pillow under the right scapula to slightly elevate the right hemithorax and maintain the hips at. Bending the right elbow and immobilize the right forearm in the table to expand the axillary space and improve access to the anterior axillary line. De brillator pads were placed routine and outside the operative eld.

Surgical process
Open the anteriorly pericardium as close to the sternum as possible to create a large ap. The ap was retracted by sutures which were inserted in the primary incision and holds the lung back, so created a large cavity for operating. When achieved full bypass ows and moderate hypothermia, using the caval tapes to secure the vena cava and then using the Chitwood clamp to occlude ascending aorta. After that antegrade HTK solution were administered and the right atrium was opened. Consecutively, using sutures to retract it to the chest wall. Then used suture to retract and set the femoral venous cannula in correct position till we can see the atrial septal. (Figure4-5) The left atrium was entered through the atrial septum, two group of sutures were used to hang the margin of the atrial septum and were draw out of the port and secured properly. After the assessment of the valve, mitral valve surgery and even tricuspid valve procedure was performed. After carefully de-airing of the heart was performed and after a TEE evaluation of the heart, cardiopulmonary bypass was disconnected and all incisions were closed.
The conventional open mitral valve surgery was performed via median sternotomy. Considering some patients were illiterate and elderly, who may be impaired in visual and cognitive functions. We used NRS to provide a simple and valid alternative assessment of pain intensity [15][16] . We used the 11-point Numerical Rating Scale (NRS-11) for assessment of pain intensity, where 0=no pain and 10=pain as bad as you can imagine. NRS-11 provides su cient level of discrimination for patients to describe the pain intensity 17 .
All the surgical wounds nally turn to scar formation. Post-surgical scars with cosmetic issues cause functional and psychosocial impairment. The evaluation of post-surgical scar formation is very important. The SCAR scale is a valid and reliable scale compared to the Vancouver Scar Scale and the Patient and Observer Scar Assessment Scale for the assessment of post-surgical scars. The scale includes six clinician questions with six parameters scored by the observer (scar spread, erythema, dyspigmentation, suture marks, hypertrophy/atrophy, overall impression), and two patient questions requiring answer only a yes/no response [18][19] . Scores can be provided by direct observation and evaluation or by using high-quality images. The patient's response to the symptoms may be either verbal or written 20 .

Statistical analysis
The SPSS 22.0 was used as statistical software, and de ned P-values <0.05 as statistical signi cance.
Mean ± standard deviation was calculated for quantitative data with normal distribution, Otherwise, the Mann-Whitney U-test was used. We used independent samples t-test or analysis of variance for continuous variables. For categorical data, the χ2 test was applied. We used Spearman's correlation coe cient for ranked data to analyze the correlation between the pain intensity or the SCAR scale scores and the SF-36 scores.

Results
No signi cantly difference in demographic and echocardiography data between the two groups (Table 1). It was a trend towards less mitral valve repair (p = 0.13),and less tricuspid valve plasty (p = 0.10) were performed in the TA group. The number of bioprothetic valves replacement was signi cantly higher in the TA group (p = 0.04), whereas preservation of subvalvular apparatus were 33 cases (p = 0.01).
Postoperative complications are shown in Table 2. The rates of postoperative adverse events were similar between the two groups. Neither serious complications nor reoperation occurred during the follow-up period. Intensive care and postoperative hospital stay were not statistically signi cant. One case of inguinal lymphatic leakage and another one with right femoral vein thrombosis was reported after minimally invasive surgery.
Patients underwent follow-up in the 3rd month after the operation. We assessed HRQoL in the two groups using the MOS SF-36, which demonstrated signi cant differences on the Bodily Pain and Mental Health subscales (Table 3). NRS scores and the SCAR scores were evaluated in both groups ( Table 4). The difference in the SCAR scores between the two groups was signi cant, with the TA group showed more satis ed with the aesthetics appearance of the incision(P 0.05). Complaints of postoperative pain were signi cantly less in TA group. The scores were signi cantly lower(P 0.05 . Evaluation on pain intensity and aesthetics showed a signi cant correlation (P < 0.05) with the SF-36 subscale evaluation results. The coe cient of rank correlation between the SF-36 scores and the NRS and SCAR scale scores is shown in Table 5. It shows that patients who get a higher score of the NRS or the SCAR score demonstrated lower SF-36 scores on bodily pain and mental health subscale. We observed that bodily pain was strongly correlated with the NRS score. Moreover, the mental health score was correlated with the SCAR scores.

Discussion
As several literature reviews have mentioned, minimally invasive mitral valve surgery (MIMVS) has been successfully performed with modi ed in techniques in the past twenty years and now is proved to be a safe and effective treatment [21][22] . Compared to conventional approaches, MIMVS provides safe and familiar results. Reviewing all the studies on mortality with MIMVS, majority studies shown no difference between the minimally invasive approach and the median sternotomy approach [23][24] . Many authors shown that MIMVS has similar morbidity and mortality rates compared with the traditional sternotomy approach mitral valve surgery but with accelerated recovery time, shorter hospital stay, decreased pain and better cosmesis 21,24−25 . With the desire to reduce the mortality and morbidity from mitral valve surgery, minimally surgery has non-stop evolved and achieved an excellently results. MIMVS has an equally good outcomes while improving in such as hospital stay, and resource utilization [26][27] . In our study, the morbidity rates after cardiac valve interventions in two group were similar. No structural valve deterioration and no valve thrombosis were observed in either group. There were no differences in major adverse events such as reoperation for bleeding, operated valve endocarditis, or reintervention.
In addition, we found there is a similar cost for total thoracoscopic mitral valve surgery compared to median sternotomy mitral valve surgery(100980.24 vs 101309.91rmb,p 0.05). Although it can reduce intensive care unit days and postoperative hospital stays, but this technique is accompanied by appreciable medical consumables costs. Consumables such as HTK solution, femoral artery and femoral vena cava cannula were associated with a signi cant increase in medical costs 26,28 .
Although mortality and morbidity after totally thoracoscopic mitral valve surgery have been reported in previous studies, the effect of totally thoracoscopic mitral valve surgery on the HRQoL has been rarely studied, especially in Chinese population. It may be in uenced by factors such as the mental state of the patient, the pain intensity and even the patient's recognition of cosmesis can be participate in. Operation safety and postoperative outcomes of totally thoracoscopic mitral valve surgery and median sternotomy mitral valve surgery have proven to be equivalent. Thus, the effect of the totally thoracoscopic mitral valve surgery on the HRQoL should be taken into consideration when evaluating and selecting the surgical approach.
In this study, we aimed to compare the effect of totally thoracoscopic approach and that of median sternotomy approach on the HRQoL of patients who had undergone mitral valve surgery. We also focused on the effect of two different approaches with respect to the pain intensity and cosmetic appearance, and the correlation between pain intensity and cosmetic appearance and HRQoL in patients.
Through our literature search we could not nd any research to compare QoL in patients undergoing mitral valve surgery by different surgical approach. There are also no comparative studies of the pain intensity and cosmetic appearance between the two surgical approaches, and no studies of the impact of pain intensity and cosmetic appearance on quality of life.
We assumed that the totally thoracoscopic mitral valve surgery and median sternotomy mitral valve surgery had similar impacts on the HRQoL of patients.
All patients in the study completed the SF-36 and provided information on the pain intensity and the SCAR scale. We used the Chinese version of the SF-36 to assess HRQoL. We found that the SF-36 scores of the minimally invasive group were superior to the median group in two subscales. We detected signi cant differences in bodily pain and mental health between the MI group and SI group. Moreover, scores on the other six subscales (including physical functioning, general healthy, role physical, vitality, social role functioning, and emotional role functioning) were higher in MI group than in the SI group.
The impact of pain intensity and cosmetic appearance on a patient's health-related quality of life, different from severe complications, is often underestimated by surgeons. R.P. Alston reported that chronic post-sternotomy pain, occurs in 40-50% of patients. Of these, 33-66% had pain lasting more than 3 months 29 . Pain after cardiac surgery is still underestimated and can be a problem. J Meyerson also reported that 28% of patients who underwent median sternotomy for cardiac surgery could suffer with non-cardiac pain. Mild pain was present in the majority of patients and severe pain was present in 1% of patients 30 . Chronic pain associated with the sternotomy incision is a well-recognized complication that have an important impact on the patient's daily life 31 . Chronic pain usually has a negative in uence on mood and can restrict the patient's activities 29 . In a study targeted to investigate persistent pain after cardiac surgery ,7% of the 244 patients reported interference with everyday life 32 .
The cause of persistent post-sternotomy pain includes rib fracture, scar formation, tissue destruction, steel wire suture, intercostal nerve trauma, infection in sternal and sternal dehiscence 33 . This totally thoracoscopic incision, which avoided divided the sternum and cracking of ribs may reduce patient distress and pain. our study proved that the postoperative pain intensity of TA was different from that of SA, and the pain intensity of TA was signi cantly lower than that of SI group. This change is consistent with other previously reported results.
Another apparently advantage of totally thoracoscopic mitral valve surgery is cosmetic appearance compare with median sternotomy approach. In this study, we also compared the SCAR scores of the two groups, and our study proved that the SCAR scores of the TA group was signi cantly better than that of the SI group.
The coe cient of rank correlation between the SF-36 scores and the pain intensity and the SCAR scores indicate that: bodily pain was closely related to the pain intensity (NRS scores), and mental health was closely related to scar aesthetics (the SCAR scale scores). The other six levels were slightly correlated with pain.
According to the data summarized above, the TA group had a better impact on HRQoL, as well as a mild pain intensity and a better cosmetic appearance, which also had a better impact on HRQoL. The postoperative complications were similar between the two groups. Therefore, totally thoracoscopic mitral valve surgery is an alternative surgery in China, with no signi cant difference in related postoperative complications, but there are signi cant differences in pain intensity, cosmetic appearance and HRQoL.
The results of this study have some limitations. First,It was a retrospective study conducted in a single institution in China selection and recall bias may contribute to the ndings. In spite of these limitations, we still believe that this study has some. Second the follow up times was short, the follow-up period was short, only about 3 months.

Conclusions
The results of this study showed that the totally thoracoscopic approach group was superior to the median sternotomy group in the effects of HRQoL, post-surgical pain intensity and the SCAR scale scores. It is recommended that you choose a method in your center based on the actual situation. Further studies with longer period of follow-up are recommended to assess HRQoL for of these two different approaches.   Soft tissue retractors used in surgery.

Figure 3
Surgical incisions for totally thoracoscopic mitral valve surgery.

Figure 4
Intraoperative view of the patient with the mechanical valve installed, and correctly position of the single two-stage femoral venous cannula.
Page 19/19 Figure 5 Suture the interatrial septum after cardiac valve intervention with femoral venous cannula correctly positioned.