Different tilting disc valves show similar rotation-dependent impairment in hemodynamic performance under a tilted implantation position

Objectives: Aortic annulus calcification can promote a tilted implantation position of mechanical valves. Such a „tilt-ramp“ often appears in the noncoronary sinus. We showed that this condition deteriorates hemodynamics of Medtronic-Hall-Easy-Fit® (MH) valves. Consequently, we subjected Ultracor® (UC) valves to tilting and rotation for comparison with the MH valve.

Material and Methods: A piston-pump pulse-duplicator was used to investigate 25mm MH and UC valves under physiological conditions (120/80mmHg, 70bpm, 60ml stroke volume). Mean pressure gradient (dPmean), regurgitation (Reg), and effective orifice area (EOA) were assessed. Valves were placed at five axial rotations (0°–180° with 0° rotation defined as the major orifice facing the top of the tilt-ramp) and three tilt angles (0°, 10°, 20°) by lifting the prosthesis in the noncoronary sinus.

Results: MH valves exhibited lower dPmean and larger EOA but higher regurgitation (diameter-enhanced design). Moderate tilting showed a rotation-independent increase in dPmean and decrease in Reg and EOA in both valves. Adverse effects on systolic performance (dPmean, EOA) were more pronounced in the UC valve. Improvement of diastolic regurgitation was more distinct in the MH valve. Further tilting caused similar but smaller changes in case of 90–180° rotation. At 0° rotation, however, the overall increase in dPmean was blunted and a dramatic increment in regurgitation occurred in both valves.

Hemodynamic data of 25mm Medtronic-Hall Easy-Fit valve (MH) and 25mm Ultracor valve (UC). Data are displayed as Mean±SD. dPmean, mean pressure gradient; Reg, regurgitation volume; EOA, effective orifice area. *p<0.05 vs. 0° tilting (same valve type), #p<0.05 vs. respective tilting (same rotation group).
	Rotation	MH Tilt 0°	MH Tilt 20°	UC Tilt 0°	UC Tilt 20°
dPmean [mmHg]	0°	3.2±0.0	3.4±0.0*	4.1±0.1#	4.8±0.0* #
dPmean [mmHg]	90°	3.2±0.0	4.0±0.0*	4.2±0.0#	6.2±0.0* #
dPmean [mmHg]	180°	3.2±0.0	4.1±0.0*	4.1±0.0#	5.9±0.0* #
Reg [ml]	0°	10.1±0.9	13.6±0.5*	7.7±0.1#	10.2±0.1* #
Reg [ml]	90°	9.8±0.8	8.1±0.0*	7.6±0.0#	7.3±0.0#
Reg [ml]	180°	9.9±0.8	8.3±0.0	7.6±0.0#	7.4±0.0* #
EOA [cm2]	0°	2.07±0.03	1.86±0.02*	1.92±0.02#	1.68±0.00* #
EOA [cm2]	90°	2.09±0.03	1.92±0.00*	1.91±0.00#	1.57±0.00* #
EOA [cm2]	180°	2.08±0.03	1.90±0.00*	1.93±0.00#	1.61±0.00* #

Conclusions: Even slight tilting showed considerable deterioration of systolic performance regardless of rotation and valve type. No substantial regurgitation was encountered. At 0° rotation, however, severe tilting caused extensive regurgitation in both valve types. Whatever valve is applied, such a position should be avoided if tilting is inevitable.