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Background: Obesity is perceived by some surgeons to be a contraindication for mini-sternotomy. This study was undertaken to evaluate outcomes of manubrium-limited(mini)sternotomy for aortic valve replacement(AVR) in obese defined as BMI≥30.
Methods: Obese patients(n=113)undergoing first-time non-endocarditic isolated AVR between November 2011 and February 2014 were identified from departmental database and divided into ‘conventional’ and ‘mini’ groups.
Results: (Table 1). The distribution of BMIs was 68 patients(30-34.9), 27 patients(35-39.9), 18 patients(>40). ‘Conventional’ group(n=44) and ‘mini’ group(n=69) had comparable preoperative characteristics. Risk profile was similar(Additive EuroSCORE I 5.98±2.3 vs. 5.78±2.2,p=0.66; EuroSCORE II 1.83 vs. 2.1,p=0.38). CPB time(conventional 84.9±19.9 min. vs.’ mini’ 95±42.1 min.,p=0.14) and cross-clamp times(conventional 63.5±16.2 min. vs. ‘mini’ 70.7±26.4 min.,p=0.11) were similar but overall operative time was significantly longer with ‘mini’ approach(conventional 171.8±39.1 min. vs. ‘mini’ 202.9±67.6 min.,p=0.007). Postoperative blood loss was less with ‘mini’ approach(conventional 359.5 ml vs. ‘mini’322.5 ml,p=0.47). Transfusion rates for RBC(conventional 25% vs. ‘mini’ 27.5%,p=0.77), FFP(conventional 27.3% vs. ‘mini’ 15.9%,p=0.15) and platelets(conventional 13.6% vs. ‘mini’11.6%,p=0.75) was equivalent. Four patients(5.8%) underwent reoperation for bleeding in the mini group compared to none in the conventional group(p=0.1). Other major complications(AF, stroke, renal failure, wound infections, pacemakers) had similar incidence. There was one death in conventional group compared to none in mini group(p=0.21). Postoperative stay was comparable with mean 8.99 days(mini) vs.8.93 days(conventional),p =0.97. On follow-up, more than mild paravalular leak was seen in 1 patient(mini) and 0 patients(conventional).
Conclusions: Manubrium-limited sternotomy is a feasible approach for AVR in the obese and achieves similar outcomes as conventional sternotomy although operative times are longer.

	Table 1:conventional vs. mini-sternotomy in obese patients (BMI ≥ 30)
		conv (n=44)	mini (n=69)	p value
	Preoperative characteristics
	mean age (yrs)	70.5 ± 11.9	68.1 ± 12.1	0.3
	females	21 (47.7%)	33 (47.8%)	0.99
	BMI	35.3 ± 5.0	34.8 ± 5.1	0.63
	Hypertension	33 (75%)	59 (85.5%)	0.16
	Pulmonary disease	10 (22.7%)	17 (24.6%)	0.82
	Diabetes	11 (25%)	16 (23.2%)	0.83
	Extracardiac arteriopathy	0	4 (5.8%)	0.1
	Neurological dysfunction	2 (4.5%)	10 (14.5%)	0.09
	Renal dysfunction	0	0
	EF good (>50 %)	36 (81.8%)	54 (78.3%)	0.7
	moderate (30-50%)	6 (13.6%)	9 (13%)
	poor (20-29%)	2 (4.5%)	4 (5.8%)
	very poor (<20%)	0	2 (2.9%)
	Add EuroSCORE I	5.98 ± 2.3	5.78 ± 2.2	0.66
	EuroSCORE II	1.83	2.1	0.38
	Operative details
	Valve bioprosthesis	38 (86.4%)	50 (72.5%)	0.08
	mechanical	6 (13.6%)	19 (27.5%)
	cross clamp time (min.)	63.5 ± 16.2	70.7 ± 26.4	0.110
	CPB time (min.)	84.9 ± 19.9	95 ± 42.1	0.140
	operative time (min.)	171.8 ± 39.1	202.9 ± 67.6	0.007
	conversions		6
	Postoperative
	blood loss (ml)	359.5	322.5	0.470
	reoperation for bleeding	0	4 (5.8%)	0.1
	reoperation for valve problems	0	2 (2.9%)	0.26
	No. of pts. transfused RBC	11 (25%)	19 (27.5%)	0.77
	FFP	12 (27.3%)	11 (15.9%)	0.15
	Platelets	6 (13.6%)	8 (11.6%)	0.75
	atrial fibrillation	20 (45.5%)	26 (37.7%)	0.41
	new stroke	0	0
	new renal failure	2 (4.5%)	3 (4.3%)	0.96
	permanent pacemaker	1 (2.3%)	5 (7.2%)	0.25
	deep sternal wound infection	1 (2.3%)	1 (1.4%)	0.75
	deaths	1 (2.3%)	0	0.21
	paravalvular leak nil/trace	41 (93.2%)	60 (86.9%)	0.58
	mild	3 (6.8%)	8 (11.6%)
	moderate	0	1 (1.5%)
	severe	0	0
	Mean postop stay - days	8.93	8.99	0.97