235-IA NEW PRESSURE MAPPING SYSTEM TOWARDS OPTIMISING CARDIAC PROSTHETIC ATTACHMENT

• Published in: Interactive cardiovascular and thoracic surgery 2014-10, Vol.19 (suppl_1), p.S70-S70
• Main Authors: Martellaro, A.J., Sauer, J.S., Lee, C.Y., Gorea, H.R., Knight, P.A.
• Format: Article
• Language: English
• ISSN: 1569-9293; 1569-9285
• DOI: 10.1093/icvts/ivu276.235

Objectives: A digital pressure mapping system based on thin film transducers is introduced to precisely quantify compression forces between sutured cardiac valve prosthetics and underlying annular tissue. This technology was developed to explore technical factors affecting the pressures generated in simulated and tissue heart models. Methods: Minimally invasive mitral valve repair and aortic valve replacement models were tested using this customised system. The 27.9 × 27.9 × 0.2 mm sensor film fitted readily under the prosthesis providing precise (248 sensors/cm2) pressure measurements across the appositional surface. Real-time pressure measurements were captured and analysed. Knot visual and tactile quality was compared to the recorded quantified pressure readings. Results: The system collected and displayed real-time data in multiple visual and analytical formats. Two- and 3-dimensional colour-gradient pressure distribution analyses compared manual suture tying to mechanical titanium fasteners in the simulation models within and between adjacent suture sites (Table 1, Fig. 1). The qualitative perception of a knot did not always correlate well with pressure readings; some tied knots appeared to secure sutures adequately but did not demonstrate high measured pressures. Table 1: Data from two mitral valve repairs (MVR) with annuloplasty rings and two aortic valve replacements (AVR) secured using manually-tied knots (MT) with a knot pusher or mechanical titanium fasteners (TF). The minimum, maximum and average suture pressures around each prosthetic, as well as the total force generated for each prosthetic are displayed. OD, outer diameter; ID, inner diameter; kgf, kilogram-force; SD, standard deviation. MVR - MT MVR - TF AVR - MT AVR - TF Sewing surface  OD (mm) 20.7 20.7 24.1 24.1  ID (mm) 27.1 27.1 19.0 19.0 Area (mm2) 179.8 179.8 168.9 168.9 Knots in area 8 8 9 9 Lowest suture pressure (mmHg) 74 1132 223 578 Highest suture pressure (mmHg) 1151 1584 1079 1013 Avg. suture pressure ± SD (mmHg) 670 ± 390 1299 ± 150 686 ± 354 841 ± 149 Total force (kgf) 2.10 4.66 2.87 3.40 Conclusion: These results encourage further pressure mapping research. Early data indicate that this technology provides valuable quantifiable information beyond conventional visual or tactile methods that can help to reveal how the number of sutures, bite spacing and knot strength affect prosthetic fixation. A better understanding of these factors could enable the use of fewer sutures yiel