The lack of stable supplies is the foremost issue limiting us from performing minimally invasive cardiac surgery. Supplies may not be existing at all, or out of stock. As we are a government-funded institution, our supply chain is affected by the assets of the country, which are currently in a poor state.
In order to conquer some of these problems, we have had to espouse groundbreaking stratagems in other resource-poor settings to make our patients’ profit splendor of minimally invasive cardiac surgery. Minimal invasive surgery offers benefits more than being only cosmetically appealing. It has comparable results to the conventional FS [1].
Our study was novel in that it utilized itemized facility costs for the procedure for each technique. Our facility divided costs based on direct patient care (including blood, laboratory, theater, room, supplies, therapy, imaging, and miscellaneous costs).
It is clear from multiple studies [3] that antegrade perfusion through the ascending aorta has several advantages as being more physiological and reduces the risk of embolization, iatrogenic aortic dissection, and groin incisions with associated complications. We used the advantage of antegrade perfusion along the minimally invasive SAVR.
A recent Cochrane review [6] encompassed seven trials with 511 participants from 7 countries. The effects of minimally invasive limited upper MS on SAVR as compared with FS were investigated [7,8,9,10,11,12,13].
In our study, we found that CBP and CCT times were not significantly different between both techniques. Notably, total operative time was significantly longer in the MS group in our first cases. In accordance with our results, there was no evidence of an increase CBP with AVR performed via an upper MS (mean difference (MD) 3.02 min, 95% CI − 4.10, 10.14; participants = 311; studies = 5; low quality). There was no evidence of an increase in aortic CCT (MD 0.95 min, 95% CI − 3.45, 5.35; participants = 391; studies = 6; low quality) [7, 9,10,11, 13].
Unlike our study, none of the included studies in this review reported major adverse cardiac and cerebrovascular events as a composite endpoint. There was no evidence of any effect of upper MS on mortality versus FS (risk ratio (RR) 1.01, 95% (CI) 0.36 to 2.82; participants = 511; studies = 7; moderate quality) [9, 12].
We calculated the duration of postoperative MV from the moment of intensive care unit admission to the moment of extubation of the endotracheal tube. We observed a shorter period of postoperative MV in the MS group compared with the FS group. We contemplate that these results were due to the upheld integrity of the thoracic cage, expressly the lower costal margin, which helps in the conservation of the respiratory mechanics. The smaller incision can be convoyed with less pain and easier respiratory movements.
The results of mini-sternotomy are promising regarding decreasing MV and ICU stay, which will have a positive economic impact. Upper inverted T-shaped hemi-sternotomy maintains the integrity of the chest wall, which will improve the chest wall mechanics and facilitate early weaning and ambulation. This is a major advantage of MS over FS other than the cosmetic results and should be the primary target of the approach. In paradox, literature reported no significant effect on MV times (MD − 1.12 h, 95% CI − 3.43 to 1.19; participants = 297; studies = 5; low quality) [7, 8, 10,11,12,13].
We observed significantly shorter ICU stay a slightly shorter, but non-significant, duration of the postoperative hospital stay in the MS group. In the literature, there was a small reduction in length of intensive care unit stays as a result of the MS (MD was − 0.57 days, 95% CI − 0.93 to − 0.20; participants = 297; studies = 5; low quality) [9]. However, there was no evidence of an effect on length of hospital stay (MD − 1.31 days, 95% CI − 2.63, 0.01; participants = 297; studies = 5; I2 = 89%; very low quality) [7, 8, 10, 11 13].
In agreement to our results, postoperative blood loss was lower in MS (MD − 158.00 ml, 95% CI − 303.24 to − 12.76; participants = 297;studies = 5; moderate quality). The literature did not attest a drop in DSWI (RR 0.71, 95% CI 0.22 to 2.30; participants = 511; studies = 7; moderate quality) or re-exploration (risk ratio (RR) 1.01, 95% CI 0.48 to 2.13; participants = 511; studies = 7; moderate quality) [5, 6].
Dissimilar to our results, a review reported no change in pain scores by upper MS (standardized mean difference (SMD) − 0.33, 95% CI −0.85 to 0.20; participants = 197; studies = 3; I2 = 70%; very low quality) [8, 10, 11].
Our study did not address pulmonary function test as an endpoint. The literature reported a small increase in postoperative pulmonary function tests with MS (MD 1.98% predicted FEV1, 95% CI 0.62 to 3.33; participants = 257; studies = 4; I2 = 28%; low quality) [6].
MS approach did not reduce perioperative atrial fibrillation (AF) compared with FS (RR 0.60, 95% CI 0.07 to 4.89; participants = 240; studies = 3; moderate quality). All of our patients, except one, were having sinus rhythm [6].
None of the included studies in the Cochrane review reported cost analyses. This was a major advantage of the present study.
More recently, the MAVRIC (manubrium-limited mini-sternotomy versus conventional sternotomy for aortic valve replacement trial) [14] a single-center, single-blind randomized study that compared AVR via manubrium-limited mini-sternotomy using a 5- to 7-cm midline incision (intervention) and conventional FS and had postoperative red cell transfusion as the primary outcome. MIS was allied to higher CBP time and reduced drain losses, but this difference did not translate in a significant reduction in blood transfusion. Additionally, conventional SAVR was found to be more cost-effective (MS had a 5.8% probability of being cost-effective) [14].
Study limitations and strength
There are some imperative shortcomings of this study. The prospective cohort study is non-randomized. The sample size was small, and the calculation was based on a single outcome of the ICU stay. Other vital outcomes were mentioned as secondary outcomes. Despite the orientation of all surgical teams with both approaches, several surgeons still preferred a traditional FS, so there might have been some selection bias as allocation was according to surgeons’ preference. The unequal number of groups was another issue. However, the groups were almost matched demographically. Despite the FS group had of higher BMI, we included cases with morbid obesity in the mini-sternotomy group up to 158 kg/BMI 60.2 kg/m2 without impact on postoperative outcomes. The study might be underpowered to detect significance in the difference in low-frequency events. This may or may not have affected some of the important outcomes such as pulmonary or neurological complications but not the ICU stay. Although we incorporated fast recovery protocols in our ICU, the duration of endotracheal intubation and length of postoperative stay was decided by the individual surgeon. No conversions were recorded.
Aortic surgery via mini-sternotomy has already been done in many centers worldwide, this study introduced MS at our centers with limited resources and achieved excellent outcomes with some benefits.
Evidently, the benefit of MS over FS is still debated, and some outcomes of each are well established as cosmetic superiority, bleeding reduction, postoperative pain, MV, and ICU stays as well as reduced pulmonary complications. In light of low resources, patients in developing countries still should benefit the splendor of MIAVR that has verified reduced budgets.