Patient characteristics are shown in table 1. TA: Tricuspid Valve, without dilation; TAD: Tricuspid Valve, with Dilation; BA: Bicuspid Valve, without dilation; BAD: Bicuspid Valve, with Dilation; BAV: Bicuspid Aortic Valve; MFS: Marfan Syndrome, without dilation; LUMC: Leiden University Medical Center, EMC: Erasmus Medical Center, AMC: Academic Medical Center. <br><br> *data unavailable, clinically defined as non-dilated by pathologist, **data unavailable for 5 patients, clinically defined as non-dilated by pathologist, ***aortic root diameters unavailable.

Table 1: Patient characteristics are shown in table 1.

Characteristic	TA	TAD	BA	BAD	MFS
	N = 11	N = 12	N = 17	N = 19	N = 8
Specimen obtained from	Post mortem, LUMC	Elective repair of the ascending aorta, LUMC	Stentless root replacement in the LUMC and six biopsies from the EMC	Elective repair of the ascending aorta, LUMC	Elective repair of a dilated aortic root (> 45 mm), AMC
Exclusion criterion	MFS	MFS	MFS	MFS	BAV
Age (years)	64.5 ± 9.0	72.3 ± 11.2	55.8 ± 9.8	60.7 ± 7.8	34.1 ± 11.8
Males (%)	54.5%	33.3%	70.1%	84.2%	62.5%
Females (%)	45.5%	66.7%	29.4%	15.8%	37.5%
Ascending aorta diameter (mean)	^*	55.0 ± 10.7	36.5 ± 7.4^**	52.7 ± 6.2	28.4 ± 12.8
Aortic root diameter (mean)	^***	^***	^***	^***	48.1 ± 3.0

TA: Tricuspid Valve, without Dilation; TAD: Tricuspid Valve, with Dilation; BA: Bicuspid Valve, without Dilation; BAD: Bicuspid Valve, with Dilation; BAV: Bicuspid Aortic Valve; MFS: Marfan Syndrome, without Dilation; LUMC: Leiden University Medical Center, EMC: Erasmus Medical Center, AMC: Academic Medical Center.

^*data unavailable, clinically defined as non-dilated by pathologist, ^**data unavailable for 5 patients, clinically defined as non-dilated by pathologist, ^***aortic root diameters unavailable.