Aus der Klink für Herz-Thorax-Chirurgie des Herz- und Gefässzentrums Bad Bevensen, Akademisches Lehrkrankenhaus der Medizinischen Hochschule Hannover Hemolysis, High-Intensity Transient Signals (HITS) and Hemodynamic Results after Aortic Valve Replacement with the Medtronic Hall Easy-Fit™ Heart Valve Prosthesis Dissertation zur Erlangung des Doktorgrades der Medizin in der Medizinischen Hochschule Hannover vorgelegt von Roland Hermann Warnecke aus Uelzen Hannover 2006 Angenommen vom Senat der Medizinischen Hochschule Hannover am 10.10.2007 Gedruckt mit Genehmigung der Medizinischen Hochschule Hannover Präsident: Prof. Dr. med. Dieter Bitter-Suermann Betreuer der Arbeit: Prof. Dr. med. Joachim Laas Referent: Prof. Dr. med. M. Strüber Koreferent: Prof. Dr. med. B. Schieffer Tag der mündlichen Prüfung: 10.10.2007 Promotionsausschussmitglieder: Prof. Dr. med. Ch. Krettek Prof. Dr. med. H.-R. Raab Prof. Dr. med. D. Berens von Rautenfeld Inhaltsverzeichnis Originalarbeit: Hemolysis, High Intensity Transient Signals (HITS) and Hemodynamic Results after Aortic Valve Replacement with the Medtronic Hall Easy-Fit™ Heart Valve Prosthesis (The Journal of Heart Valve Disease 2006;15:174-179)…..Seiten 4-9 Zusammenfassung Dissertation.....Seiten 10-17 Einleitung…..Seite10 Diskussion…..Seite 13 Zusammenfassung…..Seite17 Lebenslauf…..Seite 18 Erklärung mach § 2 Absatz 2 Nummer 5 und 6…..Seite 19 Hemolysis, High-Intensity Transient Signals (HITS) and Hemodynamic Results after Aortic Valve Replacement with the Medtronic Hall Easy-Fit™ Heart Valve Prosthesis Roland H. Warnecke1, Joachim Laas1, Hartmut Hecker2, Matthias Perthel MD1, Aiman Alken MD1 1Department of Cardiothoracic Surgery, Cardiovascular Center Bad Bevensen, Bad Bevensen, 2Institute of Biometry, Hannover Medical School, Hannover, Germany Background and aim of the study: Previous studies Transthoracic echocardiography was performed in all have shown a correlation between type, orientation patients. and valve size of mechanical heart valve prostheses Results: Among the patients, 112 (75%) showed no or and the incidence of high-intensity transient signals low HITS (34% none, 41% <30/h), while only 38 (25%) (HITS). The study aim was to investigate the pres- had elevated HITS (range 31-100/h, 14%; range ence of HITS and hemolysis and the impact of valve >100/h, 11%). Statistical analysis showed a linear size and hemodynamic parameters following aortic association between the HITS count and valve size. valve replacement (AVR) using the new Medtronic A positive correlation between valve size and LDH Hall Easy-Fit™ prosthesis. was observed; hemoglobin and bilirubin showed Methods: A total of 150 patients (120 males, 30 normal values. females; mean age 62 ± 8 years; range: 32-78 years) Conclusion: The valve size-dependent increase in underwent AVR (n = 94; 63% concomitant proce- LDH after AVR corresponds with the observation dures) with the Easy-Fit valve in its optimal orienta- that the presence of HITS increases with valve size. tion. Patients were investigated at between three and In light of these findings, the surgical approach to 36 months after AVR using transcranial Doppler implant the largest size Easy-Fit valve possible examination of the right and left middle cerebral should be discussed, given the excellent hemody- artery, and the incidence of HITS was determined. namic results provided by the valve, even in smaller For evaluation of hemolysis, serum lactate dehydro- sizes. genase (LDH), hemoglobin and bilirubin were meas- ured. These parameters were related to valve size. The Journal of Heart Valve Disease 2006;15:174-179 The Medtronic Hall™ heart valve prosthesis, which shown excellent clinical and hemodynamic outcome has been in clinical use since 1977, is a tilting-disc valve (1-3). that uses a single pyrolytic carbon disc occluder pivot- Experimental and clinical studies have demonstrat- ing within a titanium housing. The housing is ed the importance of the orientation of mechanical aor- machined into its final configuration from a single tic valve prostheses (4), and this applies particularly to piece of solid titanium. The occluder pivots about a tilting-disc valves. central guide member of the valve housing, and a The left ventricle to left ventricular outflow tract axes rotatable, fabric sewing ring is affixed to the valve. have been shown to form an angle between 140 and The design features of the prosthesis have been 150°, causing a deviation of the bloodstream line shown to introduce very low susceptibility to valve towards the convexity of the ascending aorta, with the thrombosis by eliminating areas of low-velocity flow. majority of blood flow across the non-coronary cusp Previous 20-year long-term follow up data have (5). Using an in-vivo rotation device in animal studies, the optimal orientation of artic valve prostheses was determined showing near-physiological turbulence in Presented as a poster at the Third Biennial Meeting of the Society for the Medtronic Hall prosthesis, when the great orifice is Heart Valve Disease, 17th-20th June 2005, Vancouver Convention and Exhibition Centre, Vancouver, Canada placed toward the non-coronary cusp (6). In contrast, the St. Jude Medical bileaflet valve showed significant Address for correspondence: downstream turbulences when placed in any orienta- Prof. Joachim Laas, Cardiovascular Center Bad Bevensen, Römstedter Str. 25, 29549 Bad Bevensen, Germany tion (10-12). Clinical investigations with the Medtronic e-mail: [email protected] Hall aortic valve prosthesis in optimal orientation © Copyright by ICR Publishers 2006 J Heart Valve Dis Easy-Fit™: Hemolysis, HITS, and hemodynamics 175 Vol. 15. No. 2 R. H. Warnecke et al. March 2006 showed excellent hemodynamic results, with lower (70.6%) showed combined aortic lesions. mean gradients, lower supravalvular turbulences and The study was approved by the local Ethical faster left ventricular mass regression compared to Committee of Lower Saxony, Germany; written bileaflet valves being demonstrated (7). These advan- informed consent was obtained from each of the par- tages of the tilting-disc mechanism were even more ticipating patients. pronounced in the smaller-sized valves. Introduced in 2001, the Medtronic Hall Easy-Fit™ Clinical investigations heart valve prosthesis has a new sewing cuff design Patients were investigated clinically, by transthoracic which facilitates implantation and provides an echocardiography and transcranial Doppler examina- improved tissue-to-inner diameter ratio. tion. The presence of hemolysis was assessed on the Previous studies have shown a correlation between basis of serum LDH, hemoglobin and bilirubin, all type, size and orientation of mechanical heart valve patients showing values within the normal range pre- substitutes following aortic valve replacement (AVR) operatively. Transthoracic echocardiography was per- and the incidence of high-intensity transient signals formed using an Acuson 128 XP device (Acuson, (HITS) detected by transcranial Doppler examination Mountain View, CA, USA); M-mode echocardiography (8-22). Although platelet microparticles have been as well as continuous-wave and pulsed-wave Doppler associated with micorembolic signals (23), strong evi- examinations were conducted in all patients. The dence exists that, in patients with prosthetic cardiac Bernoulli equation was used to calculate pressure gra- valves, these HITS are gaseous and not solid (24-26). dients, and the continuity equation to calculate the The deterioration of working memory in neuropsycho- EOA. Valve-related complications were registered at logical examinations has been related to the presence the follow up examination. Doppler examination of of cerebral microemboli in patients following the the right and left middle cerebral artery for detection implantation of mechanical heart valves (27,28). of HITS was conducted in all patients using 2-MHz In patients with normally functioning valve substi- probes (Nicolet, Estenfeld, Germany) fixed in a head- tutes, subclinical hemolysis with elevated levels of frame and connected to a Doppler sonography device serum lactate dehydrogenase (LDH) is a frequent find- (Pioneer TC 4040; Medilab, Würzburg, Germany). The ing (29-34). registration of signals followed the guidelines of The aim of the present study was to investigate the microembolus detection by transcranial Doppler (35). presence of HITS and hemolysis after implantation of the Easy-Fit prosthesis, and their relationship to valve Data and statistical analysis size. Furthermore, possible correlations between LDH Data were analyzed statistically using a SPSS 12.0 and HITS with effective orifice area (EOA), effective software package (SPSS Inc., Chicago, IL, USA). orifice area indexed to body surface area (EOAI) and Continuous variables were expressed as mean ± SD, peak, as well as mean, transvalvular gradients were median and range. Variables with positive skewed dis- evaluated. Clinical material and methods Patients A total of 150 patients (120 males, 30 females; mean age 62 ± 8 years; range: 32 to 78 years) (Fig. 1) was investigated at between three and 36 months’ follow up after AVR with the Easy-Fit prosthesis in its optimal orientation (intra-annular, n = 129 (86%); supra-annu- lar, n = 7 (5%); epi-annular, n = 14 (9%)). The distribu- tion of valve sizes is detailed in Table I. Additional procedures were conducted in 94 patients (63%); these included coronary artery bypass grafting (CABG) in 71 (47.3%), aortic surgery in 11 (7.4%),