Home Monitoring of Patients after Prosthetic Valve Surgery - Experimental Background and First Clinical Attempts

Abstract

Purpose: The purpose of this study was to investigate whether: 1. sound phenomena may be used to detect prosthetic valve dysfunction; 2. clinical and experimental data permit conclusions about alterations in the functional state of mechanical valves; 3. patients can record and pass on signals via Internet. Methods: 1. We implanted bi-leaflet valves in pigs. By gradually influencing the motion of the tilting discs prosthetic dysfunction could be generated. 2. Thrombosis and lysis of bi-leaflet valves was studied in sheep. This process was documented using echocardiography and acoustically by the Fast Fourier Transformation. 3. Thirty devices were set up and handed out to patients following mechanical valve replacement. All patients regularly sent data to the hospital via Internet, regardless of their location at the time. The data were evaluated by comparing them with the reference file. Results: Animal experiments proved that changes in prosthetic function led to a significant change in sound phenomena. In contrast to echocardiography alterations at an early stage (onset of thrombosis) could be reliably verified. The sensitivity was greater than in echo-control analysis. All patients regularly recorded and passed on their signals. Surveys revealed high acceptance and easy handling of the devices. Conclusions: Online registration of sound phenomena seems to be suitable for the detection of changes in prosthetic function. This led to the development of the first hand-held device for home monitoring of valve function. Registration of flow, frequency spectrum, and ECG envisaged at the next level opens up potential applications for Internet-based, remote monitoring of cardiac patients.

Key words

Valve prosthesis - follow-up - prosthetic valve sound - valve replacement

References

• 1 Horstkotte D, Piper C, Schulte H D. Thrombosierung prothetischer Herzklappen: Diagnostik und Management.  Z Kardiol. 1998;  87 (Suppl 4) 20-32
• 2 Kucukaksu D S, Akgul A, Uzun A, Tarcan O, Cagli K, Sener E, Tasdemir O, Bayazit K. Thirty years survival without anticoagulation after aortic valve replacement with a Björk-Shiley prosthesis.  J Heart Valve Dis. 2001;  10 548-549
• 3 Ebner E, Sehner J, Eger H, Ursinus E. Schallspektrographische Untersuchungen zur Diagnose von Dysfunktionen mechanischer Herzklappenprothesen (Björk-Shiley-Prothesen).  Z Kardiol. 1983;  72 174-179
• 4 Thulin L I, Reul H, Giersiepen M, Olin C L. An in vitro study of prosthetic valve sound.  Scand J Thor Cardiovasc Surg. 1989;  23 33-37
• 5 Donnerstein R L, Scott W A, Vasu A, Copeland J G. Acoustic analysis of the closing sounds of bileaflet prosthetic valves in a sheep model.  J Thorac Cardiovasc Surg. 1991;  101 1060-1068
• 6 Reynolds K J, Stephen R O. Acoustic analysis of the closing sounds of implanted prosthetic heart valves.  J Acoust Soc Am. 1995;  98 69-77
• 7 Sava H, McDonnell J T. Spectral composition of heart sounds before and after mechanical heart valve implantation using a modified forward-backward Prony's method.  IEEE Trans Biomed Eng. 1996;  43 734-742
• 8 Paulsen P K, Jensen B K, Hasenkamp J M, Nygaard H. High frequency pressure fluctuations measured in heart valve patients.  J Heart Valve Dis. 1999;  8 482-487
• 9 Masson C, Rieu R. Time-frequency analysis of the noise produced by the closing of artificial heart valves: an in vitro study.  Med Eng Phys. 1998;  20 418-431
• 10 Durand L G, Grenier M C, Inderbitzen R, Wieting D W, Stein P D. Low frequency analysis of opening sound for detection of single leg separation of Björk-Shiley convexo-concave heart valves.  J Heart Valve Dis. 1995;  4 (Suppl l) S32-S37
• 11 Walker D K, Scotten L N. Discrimination in vitro between the acoustic emissions from Björk-Shiley convexo-concave valves with and without a broken minor strut.  Med & Biol Eng & Comput. 1991;  29 457-464
• 12 Candy N, Jones H E. Processing of prosthetic heart valve sounds for single leg separation classification.  J Acoust Soc Am. 1995;  97 3663-3673
• 13 Dow J J, Plemons T D, Scarbrough K, Reeder H, Hovenga M, Wieting D W, Chandler J G. Acoustic assessment of the physical integrity of Björk-Shiley convexo-concave heart valves.  Circulation. 1997;  95 905-909
• 14 Eberhardt A, Chassaing C, Ward M, Lewandowski S. Acoustical characterization of mechanical valve condition and loading.  J Heart Valve Dis. 1995;  4 649-659
• 15 Kien G A, Jeffries B, Katz H V, Herman B A, Carey R F, Chwirut Dl, Bushar H F. Digital acoustical analysis of normal and bimodal Björk-Shiley 60° convexo-concave heart valves.  Am J Cardiol. 1990;  66 849-854
• 16 Shapira Y, Herz I, Birnbaum Y, Snir E, Vidne B, Sagie A. Repeated thrombolysis in prosthetic heart valves: a report of three cases and review of the literature.  J Heart Valve Dis. 2000;  9 146-149
• 17 Birdi I, Angelini G, Bryan A. Thrombolytic therapy for left sided prosthetic heart valve thrombosis.  K Heart Valve Dis. 1995;  4 154-159
• 18 Lengyel M, Vegh G, Vandor L. Thrombolysis is superior to heparin for non-obstructive mitral mechanical valve thrombosis.  J Heart Valve Dis. 1999;  8 167-173
• 19 Renzulli A, Vitale N, Caruso A, Dialetto G, Schinosa L, Cotrufo M. Thrombolysis for prosthetic valve thrombosis: indications and results.  J Heart Valve Dis. 1997;  6 212-218
• 20 Eitz T, Fritzsche D, Grimmig O, Frerichs I, Frerichs A, Hellige G, Minami K, Körfer R. Acoustic phenomena and valve dysfunction in cardiac prostheses: data acquisition and collection via the internet.  J Heart Valve Dis. 2003;  12 414-419