Angiology: Open Access

Angiology: Open Access
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Research Article - (2024)Volume 12, Issue 7

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Comparing Conventional and Minimally Invasive Sternotomy for Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Theodoros Mavridis*
 
*Correspondence: Theodoros Mavridis, Department of Medicine,Tallaght University,Dublin, Ireland, Email:

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Abstract

Aim: We aimed to compare the safety and outcomes of the minimally invasive approaches versus conventional sternotomy procedure for aortic valve replacement.

Methods: We conducted a PRISMA-compliant systematic review and meta-analysis. We ran an electronic search of PubMed, Cochrane CENTRAL, Scopus, and Web of Science to identify the relevant published studies. Data were extracted and pooled in the DerSimonian Liard meta-analysis model as Standardized Mean Difference (SMD) or Risk Ratio (RR) using StataMP version 17 for macOS.

Results: Forty-one studies with a total of 15,065 patients were included in this meta-analysis (minimally invasive approaches n=7231 vs. conventional sternotomy n=7834). The pooled effect size showed that minimally invasive approaches had lower mortality rates [RR 0.76, 95%CI (0.59 to 0.99)], intensive care unit and hospital stays (SMD -0.16 and -0.31, respectively), ventilation time [SMD -0.26, 95%CI (-0.38 to -0.15)], 24 h chest tube drainage [SMD -1.03, 95%CI (-1.53 to -0.53)], RBCs transfusion [RR 0.81, 95%CI (0.70 to 0.93)], wound infection [RR 0.66, 95%CI (0.47 to 0.92)] and acute renal failure [RR 0.65, 95%CI (0.46 to 0.93)] However, minimally invasive approaches had longer operative time, cross-clamp, and bypass times [SMD 0.47, 95%CI (0.22 to 0.72), SMD 0.27, 95%CI (0.07 to 0.48), and SMD 0.37, 95%CI (0.20 to 0.45)], respectively. There were no differences between the two groups in blood loss, endocarditis, cardiac tamponade, stroke, arrhythmias, pneumonia, pneumothorax, bleeding reoperation, tracheostomy, hemodialysis, or myocardial infarction, (all p>0.05).

Conclusion: Current studies have proved that minimally invasive aortic valve replacement has less mortality and better post-operative outcomes compared to the conventional approach. Future RCTs with long-term follow-ups are recommended.

Keywords

Aortic replacement; Aortic valve; Minimally-invasive; Sternotomy

Introduction

Aortic Valve Replacement (AVR) is a very common procedure worldwide, Minimally Invasive Aortic Valve Replacement (MIAVR) and Conventional Sternotomy Aortic Valve Replacement (CSAVR) are two different surgical techniques used for the replacement of the aortic valve, which is responsible for regulating blood flow from the heart to the rest of the body. AVR via median sternotomy remains the standard treatment for aortic valvular diseases [1].

However, the scientific world recently seeks less invasive procedures, so the development of less invasive approaches in general surgery has promoted the use of minimally invasive approaches within the field of cardiac surgery. [2].

Several approaches for Minimally Invasive Aortic Valve Replacement (MIAVR) have been described, but the most commonly used are the upper hemi-sternotomy and the right anterior mini-thoracotomy procedures, which have the advantage of feasible access to the aorta in addition to fewer requirements of specialized instrumentation [3]. MIAVR procedures aim to reduce surgical trauma, faster recovery, better aesthetic outcomes, decrease postoperative pain, decrease post-operative ventilation time and decrease blood loss [4]. Despite the advantages, during the procedures, access to the aortic valve through a smaller access portal leads to prolonged procedural times [5].

Minimally invasive AVR procedures support a patient’s perception of less traumatic procedures but they do not eliminate the need for Cardiopulmonary Bypass (CPB).

Therefore, there is an ongoing debate about whether minimally invasive AVR procedures truly are less invasive treatment than the conventional surgical approach through full median sternotomy [6].

Through this systematic review and meta-analysis, we aim to evaluate the clinical outcomes of patients who performed AVR via minimally invasive approaches compared with those who performed AVR via conventional sternotomy.

Materials and Methods

We followed the PRISMA statement guidelines when reporting this systematic review and meta-analysis [7]. All steps were done in strict accordance with the Cochrane handbook of systematic reviews and meta-analysis of interventions [8].

All steps of this study were prespecified, and the protocol was registered on PROSPERO before completion of full-text screening.

Search strategy

An electronic literature search was performed on PubMed, Cochrane CENTRAL, Scopus, and Web of Science to identify the relevant published studies.

The search strategy used was sternotomy or median sternotomy or full sternotomy or ministernotomy or open heart surgery or open-heart and valvular surgery or minimally invasive valvular surgery or valvular replacement or valvular implantation or Transcatheter Aortic Valve Replacement (TAVR) or aortic valve replacement or transcatheter aortic valve implantation or TAVI or Aortic valve implantation or Surgical Aortic Valve Replacement (SAVR).

Further, the references of the included studies were manually searched for any potentially eligible studies.

Study selection and data extraction

Studies were collected and organized by Endnote (Clarivate Analytics, PA, USA), duplications were removed and then a total number of 4720 articles were exported to start the study selection (screening) process.

Title and abstract screening of articles was done; this process was performed by five investigators separately. The inclusion criteria included (clinical trials and observational studies that compared the clinical outcomes of patients with aortic valvular diseases who performed MIAVR versus those who performed conventional sternotomy).

The exclusion criteria included (studies that were not in English, systematic reviews, literature reviews, case series, animal studies, non-comparative studies, and studies that did not report any of the relevant clinical outcomes, which are (mortality rate, intensive care unit and hospital stays, ventilation time, chest tube drainage, RBCs transfusion, wound infection, acute renal failure, operative time, cross-clamp and bypass times)). A second check was performed to check for any relevant studies to be added.

After the title and abstract screening phase was completed, we started the full-text screening phase which was performed by five separate investigators.

At the end of the full-text screening phase, the included studies have been identified and included for qualitative and quantitative synthesis.

Three independent investigators performed the data extraction process for each article. The data was extracted from full-text articles, tables, and figures. There were no major discrepancies between them, minor discrepancies have been resolved by the senior reviewer.

The following data were extracted from the included studies (mortality, operative time, ventilation time, ICU stay, hospital stay, prolonged ventilation, blood loss ≥ 800 ml/24 h, postoperative bleeding, 24-h chest tube drainage, blood product transfusion, endocarditis, wound infection, acute renal failure, cardiac tamponade, stroke, new atrial fibrillation, new pacemaker, cross clamp time, bypass time, respiratory failure, pneumothorax, pneumonia, pleural effusion, bleeding reoperation, tracheostomy for respiratory failure, hemodialysis, reoperation for paravalvular regurgitation and myocardial infraction).

Methodological quality assessment of included studies

According to the Cochrane handbook of systematic reviews and meta-analysis of interventions, the quality of the retrieved RCTs was assessed.

The risks of bias assessment include the following domains: Sequence generation (selection bias), allocation sequence concealment (selection bias), blinding of participants and personnel (performance bias), blinding of outcome assessment (detection bias), incomplete outcome data (attrition bias), selective outcome reporting (reporting bias) and other potential sources of bias. The authors’ judgments are categorized as ‘Low risk’ or ‘High risk’ or ‘Unclear risk’ of bias. A qualitative assessment of the observational studies was performed using the Newcastle-Ottawa Scale (NOS). This scale uses a star-based rating system to assess the risk of bias in each study. This scale’s maximum score is (9) which indicates the lowest risk of bias, and the minimum score is (0) which indicates the highest risk of bias. Scores above (7) indicate a lack of substantial bias. Quality of included studies was rated by two separate investigators. There were no major discrepancies, minor discrepancies have been resolved by a senior reviewer. Qualitative assessment of the nonrandomized clinical trials was performed using ROBINS-I tool. It is a tool for evaluating risk of bias in estimates of the comparative effectiveness (harm or benefit) of interventions from studies that did not use randomization to allocate units (individuals or clusters of individuals) to comparison groups [9]. All included studies are summarized in Table 1. The forty-one eligible comparative studies included a total of (26,808) patients, (8,742) patients underwent MIAVR and (18,066) underwent conventional sternotomy. Results of the assessment are shown in Tables 2 and 3.

Statistical analysis

This meta-analysis was performed according to the recommendations of Quality of Reporting of Meta-analysis (QUOROM) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines [10,11].

Outcomes in continuous data were presented as Standardized Mean Difference (SMD) between the two groups, the SMD with the corresponding 95% confidence intervals were pooled in the DerSimonian Liard meta-analysis model using StataMP version 17 for macOS.

Outcomes in dichotomous data from prospectively designed studies were presented as Risk Ratio (RR) between the two groups, the RR with the corresponding 95% confidence intervals were pooled in the DerSimonian Liard (DSL) meta-analysis model using StataMP (SMP) version 17 for macOS [12].

Both fixed and random effects models were tested and the random effect model was applied for outcomes because this random effect model assumes the included studies represent a random sample from the population and assigns a slightly higher weight to small studies on the expenses of larger studies.

Statistical heterogeneity among studies was evaluated by the Chi-square test (Cochrane Q test). Then, the chi-square statistic, Cochrane Q, was used to calculate the I-squared according to the equation: I2=[(Q-df)/Q] × 100%

A chi-square p value less than 0.1 was considered as significant heterogeneity. I2 values ≥ 50% were indicative of high heterogeneity.

Study design Total patients
(n)		 MIAVR (n) Conventional sternotomy (n) Main findings Reference
Prospective randomized study 80 40 40 MIAVR has important cosmetic advantages, beneficial effects in blood loss and transfusion, postoperative pain and earlier extubation and hospital discharge [5]
Retrospective observational study 426 70 356 MIAVR can be sufficiently safe and effective. These surgeries reduce the duration of hospitalization, ventilation time, blood loss, and surgical trauma. they improve cosmetic results, and speed up patient rehabilitation [12]
Retrospective observational study 1571 125 1446 MIAVR t has similar hospital outcomes compared to conventional sternotomy. The operation is quicker and does not confer any significant increase in complications or length of hospital stay [13]
Prospectively cohort study 4163 307 3856 MIAVR is a safe alternative to CAVR concerning operative and 1-year mortality and is associated with a shorter post-operative stay [14]
Retrospective observational study 506 232 274 MIAVR can be performed safely through a partial upper sternotomy on a routine basis for isolated aortic valve disease [15]
Retrospective observational study 838 73 765 Both MIAVR and conventional sternotomy had comparable early clinical outcomes in patients undergoing primary isolated aortic valve replacement. MIAVR significantly decreases postoperative pain [16]
Randomized multicenter trial 94 46 48 RDAVR by the MIS approach is associated with significantly reduced myocardial ischemic time and better valvular hemodynamic function than FS-AVR with a conventional stented bioprosthesis [17]
Retrospective cohort study 39 20 19 Partial upper hemi-sternotomy for AVR avoids unnecessary lower mediastinal dissection, reducing blood loss, transfusion needs, and total operative duration. [18]
Prospective randomized study 77 38 39 This study failed to show any improvement of respiratory function by a smaller chest incision. However, it showed a significant reduction in intraoperative bleeding [19]
Retrospective cohort study 714 61 653 Minimally invasive rapid deployment AVR had reduced bypass and ACC times and reduced length of ICU stay. [20]
Case-control-study 113 29 84 Both surgical techniques have comparable perioperative and mid-term results. MIAVR has better cosmetic results but longer duration of surgery [21]
Prospective cohort study 100 30 70 Partial upper sternotomy is a safe and effective technique for AVR. Postoperative morbidity is not significantly reduced in patients undergoing AVR by this approach [22]
Randomized trial 40 21 19 RV long-axis function was reduced after both mini-sternotomy and full sternotomy AVR, but the reduction was more pronounced in the full sternotomy group [23]
Retrospective observational study 565 182 383 AVR through a mini-sternotomy with implantation of a sutureless bioprosthesis was associated with shorter ACC and cardiopulmonary bypass time and less transfusion of packed RBCs [24]
Retrospective observational study 267 189 78 MIAVR with the sutureless Perceval bioprosthesis was a safe and reproducible procedure that was not associated with prolonged ACC or cardiopulmonary bypass time compared with a full sternotomy [25]
Retrospective observational study 140 70 70 This study has failed to show any advantage of minimally invasive AVR in early or midterm follow-up [26]
Case Control study 82 41 41 AVR is feasible through minithoracotomy. But, This approach increases surgical complexity and in this comparative study no significant benefit was shown [27]
Prospective randomized trial 40 20 20 Safety and reliability of AVR via a partial upper sternotomy is reported. MIAVR can be performed with only slightly longer operative times, good cosmetic results and significantly less blood loss [28]
Multicenter retrospective study 1057 622 435 Rapid-deployment bioprostheses allow the performance of MIAVR with similar surgical times and similar clinical and hemodynamic outcomes to conventional surgery [29]
Retrospective, single-center study 150 74 76 Ministernotomy for AVR is a safe method and does not increase morbidity and mortality. It significantly reduces post-operative blood loss and hospital stay [30]
Prospectively cohort study 984 436 548 AVR can be safely conducted through a partial ministernotomy. This approach is not associated with an increased rate of complications [31]
Retrospective observational study 68 34 34 The minimal access aortic valve replacement can be performed safely with excellent long-term results in selected patients [32]
Retrospective observational study 1341 442 899 Mortality and morbidity outcomes of MIAVR are equivalent to conventional AVR. MIAVR is associated with decreased ventilator time, blood product use, and early discharge [33]
Retrospective observational study 1180 502 678 MIAVR surgery is a reproducible, safe and effective procedure with similar outcomes and no longer operative times compared to conventional sternotomy [34]
Retrospective, observational, cohort study 709 338 371 MIAVR is a reproducible, safe, and effective procedure and reduces assisted ventilation duration, the need for blood product transfusion, and incidence of post-surgery atrial fibrillation [35]
Single-blind RCT 270 135 135 MIAVR did not reduce RBCs transfusion within 7 days following surgery when compared with conventional sternotomy [36]
Retrospective observational study 2095 1029 1066 MIAVR results in similar mortality, stroke, and reoperation rates for bleeding, , but shorter hospital length of stay compared to full sternotomy [37]
Retrospective study 200 100 100 Upper partial sternotomy can be performed safely for AVR, without increased risk of death, stroke or re-admission in 3 years postoperatively [38]
Retrospective observational study 2386 620 1766 MIAVR is a safe, effective and reproducible procedure providing as good results as FSAVR. It should be especially recommended to obese, diabetic patients with pulmonary and mobility disorders in order to improve their early recovery [39]
Retrospective observational study 754 377 377 MIAVR is a reproducible, safe, and effective procedure with similar outcomes and operating times compared with full sternotomy [40]
Open-label RCT 222 118 104 Ministernotomy AVR did not result in shorter hospital stay, faster recovery, or improved survival and was not cost-effective [41]
Retrospective observational study 3021 1319 1702 MIAVR had decreased transfusion requirements, ventilation times, intensive care unit and hospital length of stay without compromising short and long term survival compared to conventional sternotomy [42]
Retrospective observational study 627 453 174 MIAVR confers a protective effect against bleeding complications, but it is time-consuming. In addition, no differences in mortality were observed among groups [43]
Retrospective, observational, cohort study 135 42 93 MIAVR is a reproducible, safe, and effective surgical option in patients candidate for isolated AVR, and it suggests a faster recovery when used in severely obese or older patients [44]
Retrospective cohort study 236 118 118 The partial upper hemisternotomy shows similar perioperative outcome as the median sternotomy, whereas, the anterolateral minithoracotomy is associated with more perioperative complications [45]
Single center retrospective study 653 137 516 Despite the longer CPB and AoX times in the MIAVR group, there was no significant difference in early complications, mortality and mid-term survival between MIAVR and conventional AVR [46]
Retrospective observational study 511 56 455 MIAVR produces better wound cosmoses and less surgical trauma but requires more time to perform [47]
Non-randomized prospective trial 42 24 18 Upper sternotomy approach is superior to the other approaches in MIAVR, because It brings cosmetic benefits, and excellent results in a postoperative course [48]
Retrospective, nonrandomized review 100 50 50 The partial sternotomy offers a cosmetic benefit, but does not significantly reduce postoperative pain, length of stay, or cost [49]
Prospectively cohort study 176 104 72 Minimal access AVR using MECC is feasible and provides excellent clinical results. Less pain and quicker recovery was experienced among patients in this group [50]
Prospectively cohort study 36 18 18 MIAVR is associated with less blood loss, faster post-operative recovery, but increase operation time [51]

Table 1: Summary table of the included articles in this systematic review and meta-analysis.

Study ID Pre-intervention At intervention Post-intervention
Bias due to confounding Bias in selection of participants into the study Bias in classification of interventions Bias due to deviations from intended interventions Bias due to missing data Bias in measurement of outcomes Bias in selection of the reported results Results
48 low risk low risk low risk low risk low risk low risk low risk low risk of bias
49 low risk low risk low risk low risk low risk low risk low risk low risk of bias

Table 2: Results of quality assessment of the non-randomized clinical trials using ROBINS-l tool.

 Study ID   Selection   Comparability   Outcome   score/9
Selection of  patients receiving open surgery Ascertainment of exposures Demonstration that outcome of interest was not present at start of study Study controls for patient age=*Study controls for preoperative cardiac function and cardiovascular co-morbidities=** Assessment of outcomes Follow-up long enough for outcomes to occur Adequacy of follow-up of cohort
[12] * * * ** * * * 8
[13] * * * ** * * * 8
[14] * * * ** * * * 8
[15] * * * * * * 7
[16] * * * ** * * * 8
[5] * * * ** * * * 8
[18] * * * ** * * * 8
[19] * * * ** - - - 5
[20] * * * * * * * 7
[21] * * * * - * - 5
[22] * * * * * - - 5
[23] * * * ** * * * 8
[24] * * * ** * * * 8
[26] * * * ** * * * 8
[29] * * * ** - * * 7
[30] * * * ** * * * 8
[31] * * * ** * * * 8
[32] * * * ** * * * 8
[33] * * * ** * - - 6
[34] * * * * * - - 5
[35] * * * * * - - 5
[37] * * * ** * * * 8
[38] * * * ** * * * 8
[39] * * * ** * * * 8
[40] * * * ** * - - 6
[42] * * * ** * - - 6
[43] * * * ** * - - 6
[44] * * * ** * * * 8
[45] * * * ** * * * 8
[46] * * * ** * * * 8
[47] * * * ** * * * 6
[50] * * * ** * * * 8
[51] * * * ** * * * 8

Table 3: Results of quality assessment of the observational studies using Newcastle-Ottawa Scale (NOS) tool.

 Indicator Total patients (n) MIAVR (n) Full-sternotomy (n) Relative risk 95% CI p value
Hemodialysis (n) 7301 3154 4147 0.97 [0.66, 1.42]   0.86
Myocardial infarction (n) 3605 1895 1710 0.98 [0.51,1.87]   0.95
Endocarditis (n) 2215 1085 1130 0.97 [0.45, 2.11]   0.94
Cardiac tamponade (n) 2884 1404 1480 0.9 [0.60,1.35]   0.61
New atrial fibrillation (n) 7687 3320 4367 0.93 [0.79,1.09]   0.37
New pacemaker (n) 7323 3556 3767 1.07 [0.78,1.48]   0.66
Stroke (n) 12223 6274 6894 0.84 [0.65,1.10]   0.21
Respiratory failure(n) 1582 747 835 0.97 [0.62,1.50]   0.89
Tracheostomy for respiratory failure (n) 1220 293 927 0.39 [0.07, 2.21]   0.28
Pneumonia (n) 1882 898 984 1.51 [0.87,2.62]   0.14
Blood loss ≥800 mL/24 h, (n) 2597 1391 1206 0.86 [0.59,1.24]   0.41
Bleeding reoperation (n) 9467 4648 5143 1.14 [0.91,1.43]   0.26
Reoperation for paravalvular regurgitation (n) 5614 2880 2734 0.71 [0.38, 1.31]   0.27

Table 4: Summary of the included patients’ numbers, relative risks and 95% confidence intervals of the non-statistically significant outcomes

Results

Included studies and patient characteristics

Title and abstract screening of 4.720 articles was done and a total number of 4,565 studies were excluded in this phase, then the full-text screening phase was performed on 155 studies, 114 studies were excluded according to the exclusion criteria and 41 studies were included for qualitative and quantitative synthesis. Results are shown in the Prisma flow diagram (Supplementary Figure 1).

Data was pooled as Standardized Mean Difference (SMD) or Risk Ratio (RR) using StataMP version 17 for macOS. There was a statistically significant difference between the two methods in 13 outcomes (cardiopulmonary bypass time, aortic cross clamp time, operative time, ventilation time, hospital stay, ICU stay and postoperative bleeding, mortality, 24 h chest tube drainage, RBCs transfusion, wound infection, acute renal failure, and prolonged ventilation) (p value<0.05).

There was a non-statistically significant difference between the two methods in 13 outcomes (hemodialysis, myocardial infarction, endocarditis, cardiac tamponade, new atrial fibrillation, new pacemaker, stroke, respiratory failure, tracheostomy for respiratory failure, pneumonia, blood loss ≥ 800 ml/24 h, bleeding reoperation and reoperation for paravalvular regurgitation) (p value>0.05).

Results of quality assessment of the included studies

The forty-one included studies contained five RCTs, two nonrandomized trials and 34 observational studies. Results of quality assessment of the RCTs according to the Cochrane handbook of systematic reviews and meta-analysis of interventions are shown in Supplementary Figure 2.

Mortality, ventilation time, hospital stay, ICU stay, postoperative bleeding and24 h chest tube drainage

Minimally invasive procedures showed clinically and statistically significant reduction in mortality, ventilation time, hospital stay, ICU stay, post-operative bleeding and 24 h chest tube drainage. Mortality was reported in 33 studies (total patients (n)=14059, MIAVR (n)=6731, full-sternotomy (n)=7328) and the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR, [polled risk ratio=0.76, 95% CI (0.59 to 0.99), p=0.04] (polled studies were homogenous, chi-square p=0.99, I-square=0%) (Supplementary Figure 3).

24-h chest tube drainage was reported in 10 studies (total patients (n)=2197, MIAVR (n)=1112, full-sternotomy (n)=1085) and the overall SMD between the conventional sternotomy and the MIAVR favored the MIAVR,( [polled SMD=-1.03, 95% CI (-1.53, -0.53), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=95.78%) (Supplementary Figure 4).

Hospital stay was reported in 21 studies (total patients (n)=6810, MIAVR (n)=3618, full-sternotomy (n)=3192) and the overall SMD between the conventional sternotomy and the MIAVR favored the MIAVR, [polled SMD=-0.31, 95% CI (-0.49, -0.13), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=90.85%] (Supplementary Figure 5).

Ventilation time was reported in 25 studies (total patients (n)=7772, MIAVR (n)=4021, full-sternotomy (n)=3751) and the overall Standardized Mean Difference (SMD) between the conventional sternotomy and the MIAVR favored the MIAVR, [polled SMD=-0.26, 95% CI (-0.38, -0.15), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=80.06%] (Supplementary Figure 6).

Postoperative bleeding was reported in 12 studies [total patients (n)=2262, MIAVR (n)=1242, full-sternotomy (n)=1020] and the overall SMD between the conventional sternotomy and the MIAVR favored the MIAVR, [polled SMD=-0.13, 95% CI (-0.30, -0.03), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=66.43%] (Supplementary Figure 7).

ICU stay was reported in 27 studies (total patients (n)=10510, MIAVR (n)=5448, full-sternotomy (n)=5062) and the overall SMD between the conventional sternotomy and the MIAVR favored the MIAVR, [polled SMD=-0.16, 95% CI (-0.28, -0.04), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=86.15%] (Supplementary Figure 8).

RBCs transfusion, wound infection, acute renal failure and prolonged ventilation

Minimally invasive procedures showed clinically and statistically significant reduction in the post-operative RBCs transfusion, wound infections, acute renal failure and prolonged ventilation. RBCs transfusion was reported in 19 studies (total patients (n)=5496, MIAVR (n)=2552, full-sternotomy (n)=2944) and the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR [polled risk ratio=0.81, 95% CI (0.70 to 0.93), p=0.00, polled studies were homogenous, chisquare p=0.26, I2=16.01%] (Supplementary Figure 9).

Prolonged ventilation was reported in 5 studies (total patients (n)=2143, MIAVR (n)=872, full-sternotomy (n)=1271) and the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR, [polled risk ratio=0.51, 95% CI (0.29 to 0.91), p=0.02, polled studies were heterogeneous, chisquare p=0.06, I2=55.02%] (Supplementary Figure 10).

Wound infection was reported in 24 studies (total patients (n)=5795, MIAVR (n)=3033, full-sternotomy (n)=2762) and the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR, [polled risk ratio=0.66, 95% CI (0.47 to 0.92), p=0.02, polled studies were homogenous, chisquare p=0.47, I2=0.00%] (Supplementary Figure 11).

Acute renal failure was reported in 15 studies (total patients (n)=6622, MIAVR (n)=3266, full-sternotomy (n)=3356) and the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR, [polled risk ratio=0.65, 95% CI (0.46 to 0.93), p=0.02, polled studies were homogenous, chisquare p=0.35, I2=9.04%] (Supplementary Figure 12).

Operative time, cardiopulmonary bypass time, and Aortic Cross Clamp (ACC) time

Conventional sternotomy showed clinically and statistically significant reduction in operative time, cardiopulmonary bypass time and Aortic Cross-Clamp (ACC) time. Operative time was reported in 19 studies (total patients (n)=3813, MIAVR (n)=2049, full-sternotomy (n)=1764) and the overall SMD between the conventional sternotomy and the MIAVR favored the conventional sternotomy [polled SMD=0.47, 95% CI (0.22, 0.72), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=91.51%] (Supplementary Figure 13).

Cardiopulmonary bypass time was reported in 35 studies (total patients (n)=12547, MIAVR (n)=5973, full-sternotomy (n)=6574) and the overall SMD between the conventional sternotomy and the MIAVR favored the conventional sternotomy [polled SMD=0.37, 95% CI (0.20, 0.54), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=94.43%] (Supplementary Figure 14).

Aortic cross-clamp time was reported in 36 studies (total patients (n)=12147, MIAVR (n)=6068, full-sternotomy (n)=6079) and the overall SMD between the conventional sternotomy and the MIAVR favored the conventional sternotomy [polled SMD=0.27, 95% CI (0.07, 0.48), p=0.00, polled studies were heterogeneous, chi-square p=0.00, I2=96.4%] (Supplementary Figures 15-23).

Hemodialysis, myocardial infarction, endocarditis, cardiac tamponade, new atrial fibrillation, new pacemaker, stroke, respiratory failure, tracheostomy for respiratory failure, pneumonia, blood loss ≥ 800 ml/24 h, bleeding reoperation and reoperation for paravalvular regurgitation.

The overall risk ratio between the conventional sternotomy and the MIAVR doesn’t favor any of the two groups in all of these outcomes. Hemodialysis [polled risk ratio=0.97, CI (0.68 to 1.42), p=0.86, polled studies were homogenous, chi-square p=0.78], myocardial infarction [polled risk ratio=0.98, CI (0.51 to 1.87), p=0.95, polled studies were homogenous, chi-square p=0.91], endocarditis [polled risk ratio=0.97, CI (0.45 to 2.11), p=0.94, polled studies were homogenous, chi-square p=0.61], cardiac tamponade [polled risk ratio=0.90, CI (0.60 to 1.35), p=0.61, polled studies were homogenous, chi-square p=0.81], new atrial fibrillation [polled risk ratio=0.93, CI (0.79 to 1.09), p=0.37, polled studies were heterogeneous, chi-square p=0.03], new pacemaker [polled risk ratio=1.07, CI (0.75 to 1.48), p=0.66, polled studies were homogenous, chi-square p=0.31], stroke [polled risk ratio=0.64, CI (0.65 to 1.10), p=0.21, polled studies were homogenous, chi-square p=1.00], respiratory failure [polled risk ratio=0.97, CI (0.62 to 1.50), p=0.89, polled studies were homogenous, chi-square p=0.90], tracheostomy for respiratory failure [polled risk ratio =0.39, CI (0.07 to 2.21), p=0.28, polled studies were homogenous, chi-square p=0.68], pneumonia [polled risk ratio=1.51, CI (0.87 to 2.62), p=0.14, polled studies were homogenous, chi-square p=0.91], blood loss ≥ 800 ml/24 h [polled risk ratio=0.86, CI (0.59 to 1.24), p=0.41, polled studies were homogenous, chi-square p=0.45], bleeding reoperation [polled risk ratio=1.14, CI (0.91 to 1.43), p=0.26, polled studies were homogenous, chi-square p=0.37] and reoperation for paravalvular regurgitation [polled risk ratio=0.71, CI (0.38 to 1.31), p=0.27, polled studies were homogenous, chi-square p=0.67] (Table 4).

Discussion

Minimally invasive aortic valve replacement surgeries have been gaining acceptance for the last decades. Lots of studies have shown that they can be done safely with mortality and morbidity similar to the conventional sternotomy aortic valve replacement surgeries. These procedures have become a major area of research and commercial interest. This systematic review is analyzing the clinical outcomes of 41 observational and interventional studies comparing the conventional full sternotomy versus the minimally invasive procedures in aortic valve replacement.

Summary of the findings

The most important finding of this study is that MIAVR are safe procedures that conferred a survival benefit with clinically and statistically significant reduction in mortality rate as the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR [polled risk ratio=0.76, 95% CI (0.59 to 0.99), p=0.04] [polled studies were homogenous, chi-square p=0.99, I2=0%] (Supplementary Figures 23-28).

Minimally invasive procedures showed clinically and statistically significant reduction in ventilation time, hospital stay, ICU stay, postoperative bleeding, 24-h chest tube drainage, post-operative RBCs transfusion, wound infections, acute renal failure and prolonged ventilation as the overall risk ratio between the conventional sternotomy and the MIAVR favored the MIAVR.

However, the conventional sternotomy showed clinically and statistically significant reduction in operative time, cardiopulmonary bypass time and Aortic Cross Clamp (ACC) time, as the overall Standardized Mean Difference (SMD) between the conventional sternotomy and the MIAVR favored the conventional.

The overall risk ratios between the conventional sternotomy and the MIAVR don’t favor any of the two groups in hemodialysis, myocardial infarction, endocarditis, cardiac tamponade, new atrial fibrillation, new pacemaker, stroke, respiratory failure, tracheostomy for respiratory failure, pneumonia, blood loss ≥ 800 ml/24 h, bleeding reoperation and reoperation for paravalvular regurgitation (p value>0.05).

Explanation of the study findings

Minimally invasive approaches for AVR like the right anterior thoracotomy and mini-sternotomies allow smaller surgical incisions during operations compared to conventional sternotomies, which decrease the risk of bleeding and the need for post-operative blood product transfusion. That also decreases the risk of post-operative acute renal failure. Smaller surgical wounds decrease the risks of post-operative prolonged ventilation and wound infections, they also allow better cosmetic results, and speed up patient rehabilitation [12].

Minimally invasive approaches for AVR showed statistically significant increase in operative times, ACC, and cardiopulmonary bypass times compared to conventional sternotomies; that may be due to the learning curve of the new procedures. Some analyzing studies proved that with experience, the duration of surgery as well as ACC time decreased significantly and became similar between both groups [21]. Patients who performed AVR through the minimally invasive approaches had less time on the ventilator, shorter ICU and hospital length of stays with comparable short and long-term survival compared to the conventional sternotomy group.

Many studies have shown that these improved in-hospital outcomes likely result from decreased post-operative pain, facilitating quicker return of pulmonary function and mobilization [42]. Better post-operative clinical outcomes in the minimally invasive group led to lower mortality rates in this group compared to the conventional sternotomy group. This experience was also made by others, when new operative techniques were introduced. They demonstrated, that time for surgery may approximate to usual values for conventional AVR with increasing experience [52].

Significance of the work

This study expands the literature by providing strong evidence that minimally invasive approaches in aortic valve replacement are superior to the conventional sternotomy as they have lower mortality rate and, in addition, they have better post-operative prognosis and fewer post-operative complications compared to the conventional sternotomy. In this study, we analyzed data from 41 studies (7 clinical trials and 34 observational studies) with a total of (26,808) patients, making it, to the best of our knowledge, the largest and most comprehensive meta-analysis addressing this comparison to date.

Strength points

This study has lots of strong points including (1) Comprehensive research was done on multiple databases finding and including more studies than previously published systematic reviews. (2) All steps were conducted according to the guidelines of Cochrane handbook of systematic reviews and meta-analysis of interventions. (3) This manuscript is reported according to the PRISMA guidelines. (4) Methodological quality assessment of the included studies was done according to their study designs. (5) This meta-analysis includes 41 eligible comparative studies which include a total of (26,808) patients, (8,742) patients underwent MIAVR and (18,066) underwent conventional sternotomy so this large number of included patients indicates a reliable significant results.

Conclusion

This systematic review and meta-analysis proves that minimally invasive aortic valve replacement procedures have lower mortality rates, better post-operative clinical outcomes and fewer postoperative complications compared to conventional sternotomy. However, the conventional sternotomy has less operative time, aortic cross clamp and cardiopulmonary bypass times. Future well-designed blinded RCTs with long term follow- up are recommended.

Limitations

The most important limitation of this meta-analysis is the presence of significant heterogeneity in many variables analyzed such as (ventilation time, hospital stay, ICU stay, post-operative bleeding, 24-h chest tube drainage, operative time, cardiopulmonary bypass time and aortic cross-clamp time). The possible reasons for heterogeneity in these outcomes are the variability of the minimally invasive surgical techniques, sample size of each study and variable study designs.

Conflict of Interests

All authors have no conflict of interests.

References

Author Info

Theodoros Mavridis*
 
Department of Medicine,Tallaght University,Dublin, Ireland
 

Citation: Mavridis T (2024). Comparing Conventional and Minimally Invasive Sternotomy for Aortic Valve Replacement: A Systematic Review and Meta-Analysis. Angiol Open Access. 12:479.

Received: 07-Jul-2024, Manuscript No. AOA-24-32704; Editor assigned: 10-Jul-2024, Pre QC No. AOA-24-32704 (PQ); Reviewed: 24-Jul-2024, QC No. AOA-24-32704; Revised: 07-Aug-2024, Manuscript No. AOA-24-32704 (PQ); Published: 14-Aug-2024 , DOI: 10.35841/2329-9495.24.12.479

Copyright: © 2024 Mavridis T. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

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