Assessment of perceived mechanical heart valve sound level in patients

BACKGROUND AND AIM OF THE STUDY: When mechanical heart valves close, they generate an impulse that is transmitted to the patient's inner ear by two routes: (i) As acoustically transmitted sound waves; and (ii) as vibrations transmitted through bones and vessels. The aim of this study was to quantitate what patients perceive as sound from their mechanical heart valve prostheses - including both air-transmitted sound waves and bone-transmitted vibrations. METHODS: Thirty-four patients with implanted mechanical bileaflet aortic and mitral valves (St. Jude Medical and On-X) were included in the study. Measurements were performed in a specially designed sound-insulated chamber equipped with microphones, accelerometers, preamplifiers and a loud-speaker. The closing sounds measured by an accelerometer on the patient's chest were delayed 400 ms, amplified and played back to the patient through the loudspeaker. The patient adjusted the feedback sound to the same level as the 'real-time' clicks they perceived directly from their valve. In this way the feedback sound energy includes both the air- and bone-transmitted energies. Sound pressure levels (SPL) were quantitated in both dB(A) and in loudness units (sones) according to ISO 532B (Zwicker method). RESULTS: The mean air-transmitted SPL measured close to the patient's ear was 23 +/- 4 dB(A). The total air-and bone-transmitted sounds and vibrations were perceived by the patients as a SPL of 34 +/- 5 dB(A). There was no statistically significant difference in perceived sound from the two bileaflet valves investigated, and no difference between aortic and mitral valves. CONCLUSIONS: The study showed that the presented feedback method is capable of quantitating the perceived sounds and vibrations from mechanical heart valves, if the patient's hearing is not too impaired. Patients with implanted mechanical heart valve prostheses seem to perceive the sound from their valve two to four times higher than nearby persons, because of the additional bone-transmitted vibrations.     

Quality of life after heart valve replacement.

Over the last three decades, heart valve replacement has become a safe and routine surgical procedure, but replacement devices are still far from ideal. Despite improvements in materials and design, life-long anticoagulation remains mandatory for mechanical valves. The major shortcoming of the less thrombogenic bioprosthetic valves is early tissue failure. Parallel to the decrease in operative mortality after heart valve replacement, the potential quality of life for survivors has been becoming increasingly important in evaluating the late results and in selecting the appropriate device for the given patient. All factors that determine the quality of life are strongly affected by the operation due to the usually dramatic improvement both in subjective status and objective parameters postoperatively. The patient, thus, can return to normal activities, maintain self-esteem and keep normal relationships at work, in the community and at home. Psychoneurologic dysfunction was also found to decrease greatly within six months, although more than a quarter of patients were depressed preoperatively because of their disease. Overall, the experience was generally satisfying.     

Quality of life in aortic valve replacement: pulmonary autografts versus mechanical prostheses

OBJECTIVES: We sought to determine whether the quality of life (QoL) is different in patients after aortic valve replacement with mechanical prostheses or pulmonary autografts. BACKGROUND: Quality of life after mechanical valve replacement may be affected by the risk of thromboembolism and anticoagulation, and after autograft implantation, by the risk of degeneration and re-operation especially of the homograft. METHODS: Two groups of 40 patients each--one after the autograft procedure (group I) and one after mechanical valve implantation (group II)--were matched for age, gender and length of follow-up. At latest follow-up, all patients underwent routine echocardiography, the short-form health survey (SF-36) QoL survey and an extensive psychological investigation. RESULTS: Patients with an autograft showed better QoL scales, as compared with mechanical valve recipients. The difference was significant for both the physical (72.72+/-20.00 vs. 60.27+/-26.07, p = 0.021) and psychological health sum scores (74.71+/-21.03 vs. 64.71+/-23.49, p = 0.046) and for the subtests of physical functioning (73.72+/-22.44 vs. 62.77+/-25.42, p = 0.049), physical pain (88.39+/-19.13 vs. 73.36+/-27.08, p < or = 0.006), general health perception (64.37+/-17.88 vs. 51.86+/-22.86, p < or = 0.008) and health change (61.89+/-18.94 vs. 50.11+/-24.37, p = 0.02). The QoL variables did not correlate to pressure gradients, ejection fraction and New York Heart Association functional class. Psychometric tests revealed no meaningful differences between the groups. CONCLUSIONS: This study provides some evidence that patients with pulmonary autografts have greater benefit in terms of QoL, as compared with recipients of mechanical valve substitutes.     

Psychoacoustic quantification of mechanical heart valve noise

BACKGROUND AND AIM OF THE STUDY: Mechanical heart valves produce short clicking sounds during closure. These closing sounds are annoying for some patients and their partners by causing sleeping disorders or social embarrassment. Various methods for measuring the sounds have been developed both in vitro and in vivo using calculation of A-weighted sound pressure level or loudness according to ISO 532 B. The study aim was to evaluate the relevance of different psychoacoustic parameters in the evaluation of closing sounds. METHODS: Closing sounds were recorded from patients with ATS valves (n = 13), On-X valves (n = 18) and St. Jude Medical heart valve prostheses (n = 16). The sounds were recorded 5 cm above the chest of patients in a supine position, in a sound-insulated chamber. The mean peak values of loudness and sharpness were calculated and used to determine the psychoacoustic annoyance using a modification of the Widmann formula. This was verified by a listening test for ranking closing sounds of different level and sharpness by annoyance. RESULTS: There was no statistically significant independence between loudness difference or psychoacoustic annoyance difference and agreement among the test persons. For the valves, loudness ranged from 0.07 to 2.57 sone, and the psychoacoustic annoyance from 0.1 to 5.4. CONCLUSION: The results of this study showed that both sharpness and loudness have a significant influence on annoyance from closing sounds from mechanical heart valves, and indicated that the substantial variation in the parameters may be due to individual patient physiology.     

INR self-management following mechanical heart valve replacement

INR self-management can reduce severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement. Beginning anticoagulation therapy immediately in the postoperative period further reduces anticoagulant-induced complications. Data were collected from the first 600 surviving patients (from a total study sample of 1200 patients) who completed follow-up of at least 2 years. Patients were randomly divided into a self-management group and a control group. INR self-management reduced severe hemorrhagic and thromboembolic complications (P=0.018). Nearly 80% of INR values recorded by patients themselves, regardless of educational level, were within the target therapeutic range of INR 2.5-4.5, compared with 62% of INR values monitored by family practitioners. Only 8.3% of patients trained in self-management immediately after surgery were unable to continue with INR self-management. The results differed slightly between patient groups with different levels of education. We conclude that all patients for whom anticoagulation is indicated are candidates for INR self-management regardless of education level.     

Quality of life after mitral valve repair

BACKGROUND AND AIM OF THE STUDY: Mitral valve repair for degenerative and ischemic mitral valve regurgitation has been shown to be a durable procedure. The study aim was to evaluate the quality of life of patients who had undergone mitral valve repair, and to compare it to that of an age- and gender-adjusted Finnish general population. METHODS: Among 130 late survivors after mitral valve repair, 109 (83.8%) answered the RAND-36 Health Survey questionnaire; these patients form the basis of the present study. RESULTS: The Wilcoxon test showed significantly higher mental health (p = 0.04) and pain scores (p = 0.015) and a lower role functioning/physical score (p = 0.008) in the study group. The scores of the other RAND-36 Health Survey variables of the study group were similar to those of the age- and gender-adjusted general population. The mean total score for the study group was 512 (median 532, IQR 360-678), compared to 522 (median 538, IQR 468-549) in the general population (p = 0.72) (only 95 patients were included in the analysis due to isolated missing scores). CONCLUSION: The quality of life of long-term survivors after mitral valve repair, as assessed by the RAND-36 Health Survey, is similar to that of an age- and gender-adjusted general Finnish population.     

Spectral characteristics of mechanical heart valve closing sounds

BACKGROUND AND AIMS OF THE STUDY: In-vivo evaluation of cavitation is based on the registration of high-frequency pressure fluctuations that represent a mixture of both cavitation and valve closing sounds, and are difficult to separate. In order to extract the cavitation signal, a high-pass filter removing the closing sound is applied. Importantly, the cut-off frequency should be chosen based on the valve's resonance pattern. This could be determined in a cavitation-free, air-operated set-up. As air and water/blood have different physical properties that could influence resonance frequencies, it is necessary to correlate the frequency content of the closing sounds recorded in air to represent expected findings in fluid. The study aim was to characterize the impact of the surrounding media on resonance frequency of a sound source, and to develop a method capable of evaluating the spectral characteristics of mechanical heart valves. METHODS: Five different valves were investigated. An in-vitro set-up was developed where the valves were operated in an airflow-controlled setting without cavitation. The valve closing sounds were recorded and a spectral analysis was performed. The resonance frequency of a simple sound source was also recorded in water and air in order to evaluate the impact of the surrounding media. RESULTS: Resonance frequencies from the sound source measured in air increased 14% compared with corresponding measurements in water. These data were used to correct findings from the five valves that showed different spectral characteristics in air. The frequency at which 97.5% of the signal energy was contained ranged from 40.9 to 65.8 kHz. CONCLUSION: Using an airflow in-vitro model, it was possible to determine the frequency signature of different mechanical heart valves. This might provide the information needed to design the optimal high-pass filter when evaluating cavitation.     

Indication of cavitation in mechanical heart valve patients

BACKGROUND AND AIM OF THE STUDY: Cavitation may cause erosion of prosthetic heart valve material. The phenomenon has been extensively studied in vitro, and an association between the presence of cavitation bubbles and high-frequency pressure fluctuations (HFPF) has been established. In-vivo studies examining this phenomenon are scarce; hence, the study aim was to compare HFPF in patients with native, bioprosthetic or mechanical aortic valves, using both invasive and non-invasive measuring techniques. METHODS: Measurements were carried out in 16 patients implanted with a St. Jude Medical aortic valve; two control groups comprised 10 patients with normal aortic valves after coronary artery bypass surgery, and five patients implanted with a Carpentier-Edwards pericardial aortic bioprosthesis. HFPF were measured intraoperatively using a hydrophone placed near the aortic annulus, and postoperatively using the same hydrophone mounted in a specially designed water-filled sound chamber. The frequency spectrum was evaluated using Fast Fourier transformation, and the root mean square (RMS) value of the pressure signals was calculated in the frequency range 50-150 kHz. RESULTS: HFPF with intensities significantly above the noise floor were registered using both methods in the vicinity of mechanical heart valves. The RMS values of the HFPF for all three patient groups measured intra- and postoperatively disclosed a significant difference between the mechanical valves and the two control groups, indicating that there is no cavitation in the vicinity of the biological or the native valves. CONCLUSION: HFPF are present in the vicinity of mechanical aortic valves and can be measured in patients, both invasively and non-invasively. This indication of cavitation was not observed in patients with either native or bioprosthetic aortic valves.     

Diastolic heart sound produced by mid-diastolic closure of the mitral valve

Mid-diastolic closure of the mitral valve is suggested as the source for an audible diastolic sound in a patient with aortic valve and coronary artery disease. On the apex cardiogram the sound followed the rapid filling wave by 60 msec and preceded the a wave. On the echocardiogram the sound corresponded to premature closure of the mitral valve in mid-diastole. In this case an audible diastolic sound that appeared to originate from mid-diastolic closure of the mitral valve indicated a rapidly increasing left ventricular diastolic pressure with severe left ventricular failure. After treatment of the congestive heart failure, the sound diminished in intensity.     

心脏机械瓣膜置换术后抗凝的相关问题

各种类型的人造心脏瓣膜已在成千上万的患者身上置换,取得了令人满意的效果.但机械瓣膜置换术后的血栓栓塞及出血也是其严重的并发症,故需长期抗凝.该文综述了近期国内外对于心脏机械瓣膜置换术后患者抗凝治疗的发展及现状,以及抗凝相关问题的处理.对于心脏机械瓣膜术后患者的抗凝强度以及方法,国内外也仍有争议,今后机械瓣膜抗凝强度的研究仍将是重点.     

Five-year follow up of the ATS mechanical heart valve

BACKGROUND AND AIM OF THE STUDY: Between January 1, 1997 and December 31, 2001, a total of 342 patients underwent aortic valve replacement (AVR) or mitral valve replacement (MVR) with the ATS Medical prosthesis. The initial three-year phase of this study took place under a United States Food and Drug Administration-approved investigational device exemption study. The study aim was to determine the incidence of valve-related events in up to five years of follow up after valve implantation, and to assess patient disturbance from valve noise. METHODS: Patients were consecutively enrolled to undergo AVR or MVR with the ATS prosthesis. Follow up studies were conducted by patient questionnaire and/or telephone call. Follow up was 96% complete. AVR was conducted in 246 patients (80 with coronary bypass), and MVR in 96 patients (29 with coronary bypass). RESULTS: The overall operative mortality was 2.6% (n = 9; AVR 3.2%, n = 8; MVR 1.0%, n = 1), with two deaths being valve-related (0.6%). In 878 patient-years (pt-yr) of follow up (613 pt-yr for AVR; 265 pt-yr for MVR) there were an additional 22 deaths. Five deaths (0.6%/pt-yr) were valve-related: two were neuroembolic (both MVR), one from endocarditis (AVR), and two from bleeding events (both AVR). Late valve-related complications (>30 days) included 17 episodes of major bleeding (11 AVR, 1.8%/pt-yr; six MVR, 2.3%/pt-yr), five permanent neuroembolic events (four AVR, 0.7%/pt-yr; one MVR, 0.4%/pt-yr); 16 transient neuroembolic events (10 AVR, 1.6%/pt-yr; six MVR, 2.3%/pt-yr); three transient peripheral emboli (two AVR, 0.3%/pt-yr; one MVR, 0.4%/pt-yr); four paravalvular leaks (two AVR, 0.3%/pt-yr; two MVR, 0.8%/pt-yr); and one episode of valve thrombosis (MVR, 0.4%/pt-yr; AVR, 0%/pt-yr). Reoperation was required in two patients: one AVR (paravalvular leak, 0.2%/pt-yr) and one MVR (replacement due to thrombosis, 0.4%/pt-yr). CONCLUSION: These results indicate that intermediate-term results with the ATS mechanical prosthesis continue to be excellent, though further long-term follow up is warranted.     

Doppler echocardiography in assessing mechanical and biological heart valve prostheses

The study was performed to assess Doppler echocardiographic features of mitral and aortic prosthetic valves of different types with both normal and abnormal function. Two hundred and twenty-three patients with 250 prostheses were studied. Two hundred eight valves (111 mitral, 95 aortic and 2 tricuspid) were considered to be functioning normally after clinical examination, phonocardiography and M-mode and 2D echocardiography. This group enabled us to define normal Doppler echocardiographic findings for different types of prosthesis. In mitral position, peak (p) and mean (m) gradients were lower for disc prostheses and higher for ball and biological prosthetic valves; values of effective orifice area (A), calculated by pressure half-time method, were lower for biological and ball prostheses and higher in disc valves. Results were as follows: St. Jude (p 10.6 mmHg, m 3.9 mmHg, A 2.7 cm2), Duromedics (p 10.6, m 4.3, A 2.8), Bj?rk-Shiley (p 10.4, m 4, A 2.3), Omniscience (p 14.2, m 6.2, A 2.1), Starr-Edwards (p 15.9, m 5.4, A 2.1), Hancock (p 14.7, m 6, A 2), Carpentier (p 13.2, m 5.4, A 1.9). Mild regurgitation, considered "physiological", was found in 2/8 Carpentier valves and in 3/34 St. Jude prostheses. In aortic valves lower peak gradients were found in Lillehei (18.3 mmHg), St. Jude (23.8 mmHg), Bj?rk-Shiley (26 mmHg), Duromedics (27 mmHg) and higher values in Starr-Edwards (30.2 mmHg), Hancock (30 mmHg) and Omniscience (35.5 mmHg) prostheses. Mild regurgitation, considered "physiological", was found in 17% of Omniscience valves, 21% of Hancock, 33% of Duromedics, 45% of St. Jude, 60% of Bj?rk-Shiley prostheses. Hancock mitral valves implanted for over 7 years had a mean gradient higher than valves with a shorter period of implantation (7.6 vs 4.85 mmHg, p less than 0.1), whereas the effective orifice area was similar. Hancock aortic valves implanted for over 7 years had a peak gradient slightly higher than the other group (implantation less than 7 years previously), but the difference was not statistically significant. Forty-two valves (19 aortic and 23 mitral) were considered to be malfunctioning. Regurgitation Doppler signals of malfunctioning valves appeared different from those of "physiological" reverse flow; in the former cases forward gradient was higher than normal prostheses. In stenotic aortic prostheses, peak systolic gradient was greatly increased; in stenotic mitral prostheses, a very significant increase in mean gradient and a great decrease in effective orifice area were found. In 14 patients who underwent surgical re-operation and in the patient who died before operation, Doppler echocardiographic findings were confirmed.(ABSTRACT TRUNCATED AT 400 WORDS)