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Objective: Mini-sternotomy approach is becoming an accepted technique for aortic valve surgery. However, its safety for aortic root replacement has yet to be established. The aim of the present study was to compare the operative outcomes of patients who underwent aortic root replacement via mini-sternotomy (mini-Bentall) to patients who underwent conventional Bentall procedure via median sternotomy (full-sternotomy Bentall).
Methods: Between November 1998 and November 2016, 91 consecutive patients underwent the conventional Bentall procedure and 26 patients underwent the mini-Bentall procedure. The mini-Bentall procedure was performed via an upper hemi-sternotomy incision extending to the right 4^th intercostal space. In large aortic aneurysms the sternal incision extended to both right and left 4^th intercostal spaces.
Patients with concomitant procedures and those who underwent deep hypothermic circulatory arrest were excluded from the analysis. Using power=0.90 and α=0.05, we estimated that we needed to include 22 patients/group in order to detect a 30 minute reduction in the cardiopulmonary bypass (CPB) time in the mini-Bentall group.
We compared prospectively collected perioperative variables of both groups utilizing independent samples t-test for continuous variables and Fisher’s exact test for dichotomous variables. Not normally distributed continuous variables were compared using the Mann-Whitney U test. A p-value of < 0.05 was considered a-priori to indicate statistical significance.
Results: No significant differences were observed on the preoperative, operative and postoperative characteristics between the two groups (Table 1). The median CPB and aortic cross-clamp times in the mini-Bentall group were 169 min (range 133 - 252) and 148 min (range 113 - 181), respectively. The median duration of hospitalization in the mini-Bentall group was 6.5 days (range 4.0 - 16.0 days). There was no significant difference in intraoperative red blood cell unit utilization and other major postoperative complications (p>0.80). No conversions to median sternotomy were observed in the mini-Bentall group. In-hospital mortality was 1.1% in the group of patients who underwent the conventional Bentall procedure compared to 0% in the mini-Bentall group (p=1.00).
Conclusion: An upper hemisternotomy approach is safe and feasible in patients undergoing elective aortic root replacement surgery. Table 1. Preoperative, operative and postoperative data

	Full-sternotomy Bentall (n= 91)			Mini-Bentall (n = 26)		p-value
Preoperative variables
Age, years	Mean: 57 ± 13			Mean: 57 ± 12		0.94
Male	74 (81.3%)			23 (88.5%)		0.56
Hypertension	74 (81.3%)			18 (69.2%)		0.19
COPD	12 (13.2%)			2 (7.7%)		0.73
Diabetes	7 (7.7%)			1 (3.8%)		0.69
Renal Insufficiency	5 (5.5%)			0 (0.0%)		0.59
Dialysis	0 (0.0%)			0 (0.0%)		-
CAD	14 (15.4%)			2 (7.7%)		0.52
Recent CVA	8 (8.8%)			1 (3.8%)		0.68
LV Ejection Fraction (%)	Median: 60 Range: 23-66			Median: 60 Range: 20-70		0.40
Elective operation Urgent operation Emergent operation	79 (86.8%) 10 (11.0%) 2 (2.2%)			21 (80.8%) 5 (19.2%) 0 (0.0%)		0.42
Acute dissection	0 (0.0%)			0 (0.0%)		-
Chronic dissection	9 (9.9%)			0 (0.0%)		0.20
Medial degeneration	66 (72.5%)			23 (88.5%)		0.12
Marfan’s syndrome	11 (12.1%)			0 (0.0%)		0.12
Endocarditis	2 (2.2%)			2 (7.7%)		0.21
Pseudoaneurysm	0 (2.2%)			0 (0.0%)		1.0
Aortitis	1 (1.1%)			0 (0.0%)		1.0
Bicuspid aortic valve	28 (30.8%)			10 (38.5)		0.48
Redo	21 (23.1%)			4 (15.4%)		0.59
Intraoperative data
CPB time (min)		Median: 186 Range: 128-302	Median: 169 Range: 133-252		0.10
ACC time (min)		Median: 153 Range: 102-260	Median: 148 Range: 113-181		0.18
Red blood cell units		Median: 0 Range: 0-7	Median: 0 Range: 0-6		0.80
Postoperative data
ICU days		Median: 3.0 Range: 1.0-22.0	Median: 3.0 Range: 1.0-11.0		0.33
Length of stay (days)		Median: 8.0 Range: 4.0-35.0	Median: 6.5 Range: 4.0-16.0		0.10
In-hospital mortality		1 (1.1%)	0 (0.0%)		1.00
Prolonged ventilator support		8 (8.8%)	2 (7.7%)		1.00
New stroke		0 (0.0%)	0 (0.0%)		-
New renal insufficiency		1 (1.1%)	0 (0.0%)		1.00
Reoperation for bleeding		6 (6.6%)	0 (0.0%)		0.33
Postoperative atrial fibrillation		24 (26.4%)	5 (19.2%)		0.61
Permanent pacemaker implantation		8 (8.8%)	2 (7.7%)		1.00
Pneumonia		4 (4.4%)	1 (3.8%)		1.00
Reintubation		4 (4.4%)	0 (0.0%)		0.57
Tracheostomy		1 (1.1%)	0 (0.0%)		1.00

COPD = Chronic Obstructive Pulmonary Disease; CAD = Coronary Artery Disease; CVA = Cerebrovascular Accident; LV = Left Ventricular; CPB = Cardiopulmonary Bypass; ACC = Aortic Cross Clamp; ICU = Intensive Care Unit