Menoufia Medical Journal

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 32  |  Issue : 2  |  Page : 599--603

Comparison of perioperative morbidity and mortality in minimally invasive versus conventional mitral valve surgery


Ahmed L Dokhan1, Mahmoud H Mazen2, Islam M Ibrahim1, Samer WG Girgis2,  
1 Department of Cardiothoracic Surgery, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
2 Department of Cardiothoracic Surgery, National Heart Institute, Imbaba, Giza, Egypt

Correspondence Address:
Samer WG Girgis
76 Elbanafseg 3, First Assembly, Newcairo, Cairo
Egypt

Abstract

Objective The aim of this study was to evaluate a new approach for mitral valve surgery (MVS) in National Heart Institute, Egypt, comparing operative data, total hospital stay, and hospital morbidity and mortality between conventional and minimally invasive mitral valve surgery (MIMVS). Background MVS using full sternotomy is the conventional approach. Despite this procedure showing excellent postoperative outcomes, in the past two decades, MIMVS has gained consensus among surgeons as it provided greater patients satisfaction, better cosmoses, less hospital stay, and faster recovery maintaining same quality and safety. Patients and methods This prospective study was conducted on fifty patients requiring mitral valve replacement with or without tricuspid valve repair, and the patients were classified into two groups: group I (conventional) was operated on using conventional median sternotomy, and group II (minimally invasive) was operated on using video-assisted right anterolateral mini-thoracotomy and peripheral femoral cannulation. Results There was no significant difference in the preoperative data for patients of both groups. Moreover, there was no mortality in both groups but significant differences in incision length, ventilation time, blood loss (P = 0.001), blood transfusion (P = 0.01), and ICU stay (P = 0.001) were found. In addition, total hospital stay was significantly less in group II (9.6 ± 2.18 vs. 5.64 ± 0.7 days, P = 0.001). Conclusion In patients with mitral valve diseases, MIMVS is feasible for MVS without affecting the core of surgery or compromising the surgical target, with some advantages such as shorter ICU stay and faster recovery.



How to cite this article:
Dokhan AL, Mazen MH, Ibrahim IM, Girgis SW. Comparison of perioperative morbidity and mortality in minimally invasive versus conventional mitral valve surgery.Menoufia Med J 2019;32:599-603


How to cite this URL:
Dokhan AL, Mazen MH, Ibrahim IM, Girgis SW. Comparison of perioperative morbidity and mortality in minimally invasive versus conventional mitral valve surgery. Menoufia Med J [serial online] 2019 [cited 2024 Mar 28 ];32:599-603
Available from: http://www.mmj.eg.net/text.asp?2019/32/2/599/260920


Full Text



 Introduction



Although the incidence of rheumatic heart disease has steeply declined during the past four decades in the USA, it is still a major cause of cardiovascular disease in developing countries. It is estimated that 15.6 million people experience rheumatic heart disease worldwide[1].

Although the earliest open mitral valve operations were performed through a right thoracotomy, contemporary mitral valve surgery (MVS) is dominated by a sternotomy approach. Central cannulation and direct aortic cross-clamping enable mitral valve repair or replacement on a still heart with generous exposure and excellent results[2].

Sternal wound complications occur infrequently with an estimated incidence of 1–5% depending on the series. When they do occur, they are associated with a substantial morbidity and mortality[3].

By the mid-1990s, the success of laparoscopic operations in general surgery renewed an interest in minimally invasive approaches for cardiac surgery. In the late 1990s, surgeons began to explore the potential advantages of minimizing incision size in cardiac surgery[4].

In an effort to decrease the invasiveness and perioperative disability associated with heart valve surgery, cardiac surgeons have introduced 'less invasive' mitral valve operations. These operations are characterized by a nonsternotomy (usually a mini-thoracotomy) incision and some permutation of cannulation, aortic occlusion, or visualization techniques[2].

Among the advantages offered by minimally invasive valve surgery are a less traumatic operation with less blood loss, less postoperative pain, and more rapid recovery[5].

The aim of the study was to evaluate this new technique introduced in Egyptian National Heart Institute comparing the postoperative pain, ICU and hospital stay, recovery speed, cosmoses, and hospital mortality and morbidity between minimally invasive mitral valve surgery (MIMVS) and minimally conventional mitral surgery.

 Patients and Methods



From December 2013 to December 2016, 50 patients were prospectively enrolled in our study and randomly assigned into two equal groups by simple randomization technique (odd and even numbers): group I underwent conventional median sternotomy (n = 25) and group II underwent right anterolateral minithoracotomy (mini group, n = 25). All patients in our study were operated in the National Heart Institute (Egypt) and in Menoufia University Hospital.

Ethical approval for this study was obtained from the Ethics Committee for Scientific Research in Menoufia University, and also an informed consent was obtained from all patients before the surgery.

All patients with mitral valve disease candidate for mitral valve repair, concomitant aortic valve disease, concomitant ischemic heart disease, previous open heart surgery, multiple preoperative comorbidities (liver failure, renal failure, respiratory failure, and advanced malignancy), and history of previous cerebrovascular disease or peripheral vascular disease were excluded from the study.

Operative techniques

Conventional general anesthesia, standard cardiopulmonary bypass, antegrade warm blood cardioplegia, and standard left atriotomy were done in all patients in both groups.

In group I, conventional median sternotomy incision was 15–23-cm long, starting 1–2 cm below the sternal notch down to the xiphoid process. The full sternotomy was performed from the sternal notch and extending downward to the xiphoid process. Conventional aorto-bicaval cannulation of the heart was performed. Mitral valve exposure and replacement was through the standard paraseptal left atriotomy. Tricuspid valve was exposed the right atriotomy and was repaired by using De-vega on beating heart when needed.

In group II, mini-incision was 4–7 cm long, over the forth intercostal space just below the nipple (in the infra-mammary crease in most women). Heart was accessed through the fourth intercostal space, and pericardium was opened 2 cm ventral to the right phrenic nerve. Peripheral femoral artery and vein cannulation is performed through a small 3–4-cm transverse incision in the groin. Transesophageal echo guidance is essential to confirm correct luminal passage and destination of the venous cannula. Transthoracic aortic clamp was used through a separate 1-cm incision downward and lateral to the thoracotomy incision. Mitral valve exposure and replacement and also tricuspid valve exposure and repair were done with the aid of videoscope introduced through a separate 1-cm incision and connected to video-assistance monitor. Moreover, a special atrial retractor was used to aid exposure. The surgical technique was the same as in group I.

After operation, all patients were transferred to ICU mechanically ventilated till becoming hemodynamically stable, extubated, and accepted drainage. The patient was transferred to ward after removal of chest drains till adjustment of target international normalized ratio. Assessment of pain using the visual analogue score was done on second and fifth postoperative day, along with assessment of wound to exclude infection, and then patient was discharged with recording all ICU data and events, ICU and hospital stay in days.

Follow-up of patients was done in outpatient clinic at 1-week, 1-month, and 3-month intervals from discharge date, including clinical examination for vital signs and echocardiography only at 1-month visit, with evaluation of length, shape of scar, and pain score at 1-month visit.

Statistical analysis

Data were collected, verified, and edited on a personal computer and then analyzed by SPSS version 19 (IBM Corp., Armonk, New York, USA), EPICalc software program (Informer Technologies, Inc. company, 6800 Altamor Drive, Los Angeles, CA 90045, USA). to get the final result. Arithmetic mean and SD were calculated. T-test was used to compare values. The χ2-test was used for qualitative values. P value of less than 0.05 was considered significant.

 Results



The two groups were matched, with no statistically significant difference regarding age, sex, and BMI. Moreover, there was no statistically significant difference between the two groups in preoperative NYHA classification [Table 1].{Table 1}

Echocardiography done preoperatively showed no significant difference in the preoperative ejection fraction (EF) between the two groups, with a mean EF of 59.93 ± 6.32 in group I versus 58.57 ± 5.85 in group II (P = 0.38). Moreover, no significant difference was observed between the two groups regarding preoperative cardiac dimensions, pulmonary artery pressure, and left atrium dimension [Table 2].{Table 2}

Group I included 16 cases of mitral valve replacement only and nine cases of mitral valve replacement plus tricuspid valve repair. In group II, there were 21 cases of mitral valve replacement only and four cases of mitral valve replacement plus tricuspid valve repair.

Total operative time (TOT), total cross-clamp time (TCCT), and total bypass time (TBT) in minutes were longer in group II, with statistically significant difference (mean TOT in group I 177.28 ± 24.69 vs. 204.6 ± 18.93 in group II, P = 0.001; mean TCCT in group I 41.40 ± 7.52 vs. 67.24 ± 7.45 in group II, P = 0.001; and mean TBT in group I 63.8 ± 11.02 vs. 112.48 ± 9.75 in group II, P = 0.001), but with no statistically significant difference in inotropic support needed (P = 0.39) [Table 3].{Table 3}

There was statistically significant difference between the two groups regarding length of the surgical incision (mean in group I 19.28 ± 2.15 vs. 5.96 ± 0.84 cm in group II, P = 0.001), ventilation time (mean in group I 8.56 ± 2.38 h vs. 3.48 ± 1.29 in group II, P = 0.001), amount of blood drainage (mean in group I 578 ± 218.94 vs. 278 ± 123.39 ml in group II, P = 0.001), need of blood transfusion (P = 0.01), ICU stay (mean in group I 2.64 ± 0.86 vs. 1.32 ± 0.48 days in group II, P = 0.001), and total hospital stay (mean in group I 9.6 ± 2.18 vs. 5.64 ± 0.7 days in group II, P = 0.001) [Table 4].{Table 4}

Echocardiography 1 month postoperative revealed no statistically significant difference between both groups in EF with a mean EF of 62.5 ± 9.8 in group I versus 62 ± 10.4 in group II (P = 0.86), however there was statistically significant difference between both groups in pain score (mean in group I 1.84 ± 0.69 vs. 1.48 ± 0.51 in group II, P = 0.04) and time needed to return to normal activity mean in group I 8.72 ± 2.21 vs. 3.96 ± 1.02 weeks in group II, P = 0.001) [Table 5].{Table 5}

 Discussion



Full median sternotomy is the current approach in cardiac surgery. It is not devoid of drawbacks for the patients (postoperative bleeding, wound infection, back pain, sternal dehiscence, and visible scar). The search for smaller incisions suited specifically for each different operation is therefore appropriate[6].

The age groups in our study are younger than the age groups in other studies. Sündermann et al.[7] reported a mean age of 57 ± 9.6 years. The younger mean age in our series may be attributed to earlier and repeated affection by rheumatic fever, which is endemic in most developing countries including Egypt.

In our study, the pathology of the mitral valve lesion was pure mitral stenosis in 13 patients in group I and group II, pure mitral regurgitation in three patients in group I versus six patients in group II, and double mitral lesion was present in nine patients in group I versus six patients in group II. Navia and Cosgrove[8] reported that indications for MVS was valve insufficiency in 90% of patients, mitral stenosis in 4%, and mixed pathology in 6% of patients; the main etiology was degenerative mitral valves in 82%. This difference is attributed to the fact that the main etiology in our study was rheumatic mitral valve.

Preoperative echocardiography parameters showed no statistically significant difference between the two groups in EF, pulmonary artery pressure, and left atrial dimension, yet many studies showed that patients with a small left atrium are more easily approached through the left lateral prone position[9].

As one of the main concerns of many patients is the length and shape of scar postoperatively, MIMVS offers a shorter skin incision and better cosmetic results. In our study, the length of skin incision was significantly shorter in group II than in group I, emphasizing the same results found with Cheng et al.[10].

One of the disadvantages of the right mini-thoracotomy approach is that it needs a learning curve for the surgeon and team to be able to perform the procedure through a smaller incision in a faster time[11]. In our study, the TOT, TCCT, and TBT were significantly longer in group II compared with group I. This observation is consistent with other studies. Shinfeld et al.[12] reported that in the beginning of the learning curve, cross-clamp time was 25 min longer in the minimal invasive group compared with sternotomy group. However, with experience, cross-clamp time improved in their center but still remained 15% longer in the minimally invasive group.

In our study, no attempt was done for extubating the patient in the operating theater. All patients in both groups required mechanical ventilation. In group I, the mechanical ventilation time was significantly longer. Sündermann et al.[7] and Cheng et al.[10] studies showed that postoperative mechanical ventilation is significantly lower in patients undergoing MIMVS, and it may be related to less postoperative pain and minimal effect on respiratory mechanics.

One of the most important advantages of the less invasive technique is the lower incidence of postoperative bleeding and lesser requirement for re-exploration. In our study, the amount of blood drainage and the need for blood transfusion were significantly lower in group II compared with group I. Svensson et al.[13] reported that less perioperative bleeding and fewer blood transfusions are likely owing to the less extensive mediastinal dissection required for the minimally invasive approach.

The ICU stay and the total hospital stay were significantly shorter in group II than group I. This is consistent with other studies by Yung et al.[14] and Aybek et al.[15] Thoracotomy proved to be superior to sternotomy in terms of postoperative ICU stay. The reason that in our study we had longer ICU stay is that we do not discharge patients from the ICU before removal of the chest tubes.

Evaluation of pain by visual analogue pain scale was done in our study. The MIMVS group had pain score significantly lower than the conventional group. Walther et al.[16] reported that postoperative pain ranged from 2.7 ± 1.6 in group II to 3.82 ± 0.99 in group I. Moreover, they reported that pain levels decreased progressively during the first 7 days postoperatively, and they found that from the third postoperative day onward, patients who underwent anterolateral mini-thoracotomy experienced less pain. This is an important finding that may be explained by the fact that mobilization of patients with a lateral mini-thoracotomy is rather painless as compared with median sternotomy, in which strain caused by mobilization causes bony friction.

There was no significant difference in EF% between both groups 1 month postoperatively. Transthoracic echocardiography showed well-functioning mitral prosthesis with no paravalvular leak in both groups.

The pain score using the visual analogue scale was compared in the two groups and was statistically significant lower in the MIMVS. Of all the studies published on MIMVS versus conventional MVS, very few have reported on pain-related outcomes, and this should be an important part of any future research agenda[10].

Moreover, in our study, there was a high statistically significant difference between both groups regarding return to work and was much shorter in group II. Cheng et al.[10] found that return to normal activity was significantly faster for MIMVS versus conventional MVS.

MIMVS has shown excellent results in terms of mortality, morbidities, and pain, providing shorter hospital stay and faster recovery and return to normal activities, which translate into less use of rehabilitation resources and healthcare costs.

 Conclusion



We can deduct from the previous studies for both groups of patients that minimal invasive approach is feasible for MVS without affecting the core of surgery or compromising the surgical target with some advantages and disadvantages and some limitations.

MIMVS is a safe alternative to a conventional approach and is associated with less morbidity, especially with an expert surgeon in simple mitral valve surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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