W. Schlick, M.D., J. Mlczoch, M.D., G. Kronik, M.D., and E. Wolner, M.D.

Transcription

1 Implantation of the Durornedics Bileaflet Cardiac Valve Prosthesis in 400 Patients W. Klepetko, M.D., A. Moritz, M.D., G. KhunlBrady, M.D., W. Schreiner, Ph.D., W. Schlick, M.D., J. Mlczoch, M.D., G. Kronik, M.D., and E. Wolner, M.D. ABSTRACT From September, 1983, to April, 1986, 451 Duromedics bileaflet cardiac valve prostheses were implanted in 400 patients at our institution in Vienna. Aortic valve replacement was done in 190 patients, 157 underwent mitral valve replacement (1 patient also underwent tricuspid valve replacement), 52 underwent double valve replacement, and 1 patient underwent isolated reoperation for tricuspid valve replacement, Concomitant procedures were performed in 86 patients (21.5%). Sixtyone patients (15.2%) had undergone previous cardiac surgery; 32 (8%) had undergone earlier valve replacement. The early mortality rate (within 30 days) was 6.25% (25 patients). Followup was done on 337 surviving Austrian citizens; this represents 429 patientyears. The late mortality rate was 2.1% per patientyear (9 patients). We observed paravalvular leak in 3 patients (0.7% per patientyear), thromboembolism in 4 (0.9%), prosthetic valve endocarditis in 5 (1.2%), and anticoagulantrelated hemorrhage in 10 (2.3%). Valve failure occurred in 8 patients (1.8%). We conclude, therefore, that good clinical results and a low complication rate can be achieved with this new type of valve. The search for betterperforming prosthetic valves requires that for clinical use there be accurate control, with patient safety a primary objective [l]. Whereas longterm results over periods greater than 10 years are useful for comparing different valve models, the prompt identification of early problems by analysis of shortterm results is necessary to avert widespread implantation of suboptimal valves. Gersh and coworkers [l] have formulated criteria for the clinical evaluation of new prosthetic valves. Our shortterm experience with the Duromedics valve involves 400 implantations, and our followup includes 429 patientyears. The Duromedics valve has been used by 30 clinical centers worldwide [2]. To our knowledge we maintain the largest reported number of clinical implantations. Therefore, we would like to report our clinic's shortterm results with the Duromedics bileaflet valve. Evaluation was done according to the criteria of Gersh and colleagues [l]. From the Second Surgcal Department, Cardiological Department, and First Medical Department, University of Vienna, Vienna, Austria. Accepted for publication Mar 13, Address reprint requests to Dr. Klepetko, Second Surgical Department, University of Vienna, Spitalgasse 23, A1090 Vienna, Austria. Patients and Methods From September, 1983, to April, 1986, 451 Duromedics valves were implanted in 400 patients in our department. Aortic valve replacement (AVR) was done in 190 patients, 157 patients underwent mitral valve replacement (MVR) (1 patient also had tricuspid valve replacement [TVR]), 52 underwent double valve replacement (DVR), and 1 patient underwent a second tricuspid valve replacement. Mean age of the patients was 51 years (range, 7 to 79 years); 52% were male and 48% female. The cause of valve disease was undetermined in 42.2% of our patients; 34.5% had rheumatic valvular disease, 8.0% required reoperation after previous valve replacement; 5.7% had congenital valve failure, and 3.9% had active endocarditis (Fig 1). Stenotic valve lesions were present in 49.5% of patients requiring AVR. Stenosis as well as mixed disease were found in 39.7% of patients undergoing MVR. Preoperative cerebral and peripheral embolism occurred in 6.3% of patients with AVR, in 26.8% with MVR, and in 15.7% with DVR. Angina was present in 38.4% of patients with AVR, and 18.9% had coronary heart disease. The mean gradient across the valve in aortic stenosis was 78 f 27 mm Hg; in mitral stenosis it was 14.7? 5 mm Hg. Mean pulmonary artery pressure was mm Hg in AVR, and was increased to 36.3? 14 mm Hg in MVR. Pulmonary artery pressures were highest in DVR ( mm Hg). Ninetythree percent of patients with AVR were in sinus rhythm preoperatively compared with only 22% of patients with MVR and 31% with DVR. Associated procedures were done in 86 patients (21.5%)(Table 1). These procedures included 39 aortocoronary bypass operations, 10 tricuspid valve repairs, 6 mitral valve repairs, 13 aortic annular enlargements, 6 carotid artery endarterectomies, and 12 miscellaneous procedures. Valve sizes most frequently implanted were 23 mm (36.7%) and 25 mm (28.1%) in the aortic position, and 29 mm (39.4%) and 31 mm (39.4%) in the mitral position. Operative Technique The operative technique was similar for each valve; the standard cardiopulmonary bypass technique was used under moderate systemic hypothermia. Myocardial protection was achieved with cold St. Thomas's cardioplegia and topical cooling with iced saline. 303 Ann Thorac Surg , Sep 1987

2 ~ 304 The Annals of Thoracic Surgery Vol 44 No 3 September 1987 Rheumatic 34.46% 42.23% Fig 1. Cause of valve lesions in 400 patients. Table 1. Additional Procedures Others 5.70% Congenital 5.70% Active endocarditis 3.89% Valve replacement 8.03% tion and/or death were caused by (1) ACH, (2) prosthetic valve occlusion (thrombotic or tissue ingrowth), (3) TE, (4) PVE, (5) hemodynamic prosthetic valve dysfunction, (6) reoperation for any other reason, or (7) paravalvular leak. Sudden death [5] was included in our definition of valve failure, although it is not included in the Stanford definitions. Perioperative mortality includes all deaths occurring within 30 days after the operation or during the same hospital admission. Statistical Analysis The calculation of survival rates and incidence of events was done according to the KaplanMeier method. Results are presented as a percentage plus or minus the standard deviation. Linearized incidences of events were estimated using standard techniques. Procedure AVR MVR DVR Coronary artery bypass grafting Tricuspid valve annuloplasty Mitral valve annuloplasty Aortic annular enlargement Carotid artery endarterectomy Other Total AVR = aortic valve replacement; MVR = mitral valve replacement; DVR = double valve replacement. Mean aortic crossclamp time was min for AVR, min for MVR, and min for DVR. Implantation of the prosthetic valve was performed with pledgetsupported interrupted 20 TiCron mattress sutures. Postoperatively the patients received 5,000 units of heparin subcutaneously every 8 hours. On the fourth postoperative day, permanent anticoagulation was begun with phenprocoumon (Marcumar). Definitions Valverelated complications were defined according to modified Stanford criteria [3]. Paravalvular leak referred to all instances in which a valve leak was suspected on clinical examination and was confirmed by further investigations. The diagnosis of prosthetic valve endocarditis (PVE) was accepted if at least two of the following criteria were present: (1) fever, splenomegaly, new cardiac murmur, or peripheral embolism; (2) two blood cultures positive for the same organism; (3) echocardiographic evidence of valve dysfunction, vegetations, or abscess cavity formations [4] (not included in the definitions of the Stanford group); and (4) histopathological evidence of infective endocarditis at reoperation or postmortem examination. Thromboembolism (TE) was defined as any new focal neurological deficit unless proved otherwise. Anticoagulantrelated hemorrhage (ACH) included all episodes of bleeding resulting in hospital admission or transfusion. Valve failure was defined broadly if reopera Followup Followup did not include 38 foreign patients; only the 337 surviving Austrian patients were included. Data are presented for patients who are at least 3 months postoperation. A questionnaire was sent to patients at 3 months and 2 years postoperatively to obtain information about their physical condition, complications, or other diseases. At 6 months postoperatively, the patients were invited to our outpatient department where history and physical examination, electrocardiogram, laboratory tests, and control of anticoagulation therapy were performed. At the 1year followup, the patients were again seen in the outpatient department and chest roentgenograms, echocardiograms, and lung function tests were done in addition to the previous routine. Two patients were lost to followup (99.5% complete). We have accumulated a followup of 429 patientyears. Results Hospital Mortality Overall hospital mortality was 6.25% (25 patients). There were 8 deaths after AVR (4.2%), 11 after MVR (6.8%), and 6 after DVR (11.7%). Low cardiac output syndrome was the cause of death in 9 patients. Three of these patients had AVR, one combined with closure of a ventricular septa1 defect, and one for active endocarditis. The other 6 patients underwent MVR. In 2 of these patients, valve replacement was done for failure of a bioprosthesis, and 2 patients had a history of earlier mitral valvulotomy. Myocardial infarction was fatal in 5 patients. Three patients underwent AVR with multiple coronary artery bypass grafting. One patient underwent MVR in the presence of diffuse coronary sclerosis, and 1 patient underwent DVR with aortic ring enlargement. Autopsyproved cerebral infarction was noted in 1 patient in addition to myocardial infarction. There were 3 patients with noncardiac sepsis (1 had mediastinitis, 1 had acute necrotizing colitis, 1 had generalized sepsis). Two patients died of PVE. One of them underwent reoperation in an outside hospital 29 days after MVR

3 305 Klepetko, Moritz, KhiinlBrady, et a1 Duromedics Bileaflet Valve Table 2. Valverelated Complications PL Estimates Linearized Rate of % Free Complication Total (%/patientyear) at 2 Years" i 0.00,,.,,,,,,. ',,,,.,..,,., Paravalvular leak f 1 Thromboembolism ? 1 PVE c 2 ACH t 5 Valve failure ? 4 'Values are C SD WE = prosthetic valve endocarditis; ACH = anticoagulantrelated hemorrhage; DL = product limit determined by the KaplanMeier method. because of paravalvular leak in the presence of PVE. The other patient had double valve rereplacement for acute endocarditis of two bioprostheses. One patient succumbed to a cerebral stroke after DVR caused by intracranial carotid artery stenosis. Other causes of death were ventricular perforation in 2 patients and uncontrollable hemorrhage, pulmonary embolism, cerebral stroke, and aortic dissection after AVR in 1 patient each. Late Mortality Late mortality was 2.1% per patientyear (9 patients). Two patients died of PVE. In one of these patients, tissue ingrowth led to a partial valve occlusion. One patient died of progressive myocarditis without involvement of the valve. Two patients died of progressive heart failure; prosthetic dysfunction was excluded by echocardiography. One patient died of thrombotic valve obstruction 25 months after DVR. One patient who had been asymptomatic suffered sudden death 3 months after AVR; no autopsy was performed. One patient died of pulmonary embolism 5 months after AVR, and 1 patient succumbed to cerebral bleeding. Survival rates were % after 12 months and 95 & 4% after 24 months when calculated by the Kaplan Meier method. Including the perioperative mortality, survival rates after 1 year were 89 k 10% and after 2 years, 87 * 12% (Fig 2). ValveRelated Complications (Table 2) Paravalvular leak was observed in 3 patients (0.7% per patientyear); % had not experienced a leak after 2 years (Fig 3). One patient underwent reoperation for that complication. Postoperatively, paravalvular leak recurred, and further treatment was conservative. Two other patients were treated conservatively. I'VE occurred in 5 patients (1.2% per patientyear); 97 f 2% were free of PVE after 2 years (Fig 4). Two patients underwent reoperation for acute PVE and subsequently died of recurrence during hospitalization. Two patients 0.96 I; oom I / 1 j _,,,,,,,,, 0 6 I nmins PffilOPmlIUE o.34{,,,,,,,,,, j Fig 4. Incidence of prosthetic valve endocarditis as calculated by the method of KaplanMeier. (Results are the percentpge free from event k SD.) who experienced PVE after MVR died during followup. These four patients have been mentioned before. One patient with PVE after AVR was treated conservatively. Thromboembolism occurred in 4 patients (0.9% per patientyear); 98 f 1% were free of TE after 2 years (Fig 5). One patient who died on the third postoperative day of MCI after AVR had signs of cerebral embolism at au

4 306 The Annals of Thoracic Surgery Vol 44 No 3 September F ' ; 0.98: F R n E ;s I* F R.' 0.94 F E 0.91 E N 0 ' n 1 : 95f4, ,,,,,,,,, ',,,,,,,,,, I 0.89,,,,,,,, Fig 5. Incidence of thromboembolism as calculated by the method of KaplanMeier. (Results are the percentage free from event k SD.) Fig 7. lncldence of valve failure as calculated by the method of KaplanMeier. (Results are given as the percentage free from event f SD.) 0.96 I F PREOP , NYHA 0.80,...., OPPROC D RVR flullhs POSTOPERRTIUE Fig 6. Incidence of anticoagulantrelated hemorrhage as calculated by the method of KaplanMeier. (Results are given as the percentage free fromevent 2 SD.) 21 DUR en0 (NR Fig 8. New York Heart Association (NYHA) functional classification preoperatively and after 12 months. (OpProc = operative procedure; AVR = aortic valve replacement; MVR = mitral valve replacement; DVR = double valve replacement.) topsy. Three patients had transient ischemic attacks during followup. In 1 patient colorectal carcinoma with hepatic metastasis was present. All patients were treated conservatively. Anticoagulant therapy at the time of the event was inadequate in 1 patient. ACH was observed in 10 patients (2.3% per patientyear); 94 & 5% were free of ACH after 2 years (Fig 6). One patient died of cerebral bleeding during followup. One patient was operated on for a bleeding intracranial aneurysm. Hematuria occurred in 5 patients and was combined with gastrointestinal bleeding in 1 patient. Hematemesis occurred in 1 patient, 1 patient experienced metrorrhagia, and 1 had subcutaneous bleeding. Valve failure was observed in 8 patients (1.8% per patientyear); all have been mentioned in preceding sections. After 1 year 97 & 2% were free of valve failure; % had not experienced failure after 2 years (Fig 7). Four patients died of PVE, 1 with tissue ingrowth of the valve. One patient was reoperated on for paravalvular leak. One patient died of cerebral bleeding, 1 of sudden death, and 1 of thrombotic valve obstruction. Condition Mean New York Heart Association (NYHA) functional classifications dropped from 3.17 k 0.74 preoperatively to 1.69 * 0.74 after 3 months; to after 6 months; and to 1.50 * 0.71 after 12 months. The mean benefit of the operation was an improvement of one or two NYHA classes. This could be found after AVR, MVR, and DVR, with the best results after AVR (Fig 8). Laboratory Results Normal hemoglobin levels were found in all groups of patients preoperatively and after 6 and 12 months, indicating that any hemolysis was well compensated. Lactate dehydrogenase (LDH), the most reliable indicator of hemolysis, increased from 234 & 113 IUL preoperatively to 366 * 147 IU/L after 6 months and to IU/L after 12 months. Preoperative haptoglobin levels of 86.7 & 92.2 mg/dl dropped to mgldl after 6 months and to 19.4 * 22.8 mg/dl after 12 months. Free plasma hemoglobin of mg/dl preoperatively changed to 5.8 * 4.0 mg/dl after 6 months and to mgldl after 12 months. These parameters indicate a slight but wellcompensated hemolysis caused by the prosthesis. Platelet count was not influenced by the valve implantation and ranged between 180/nl and 190/nl, excluding severe platelet activation.

5 307 Klepetko, Moritz, KhunlBrady, et al: Duromedics Bileaflet Valve Comment The Duromedics valve (61 is a bileaflet mechanical prosthesis with curved leaflets enhancing central flow (Fig 9). It has a unique articulating mechanism designed to reduce thrombus formation in this critical area. Leaflet articulation is achieved by means of ballshaped protrusions that move in elongated sockets in the valve housing. The ball portion of each leaflet translates prior to rotation of the leaflet during the valveopening period. During valve closure, the movement consists identically of translative and rotative components. This, together with the clearance between protrusion and sockets, results in a pumping action that moves the blood in the hinge mechanism, thus preventing thrombus formation. The valve is designed so that there is no load to be carried by the pivot mechanism, and the forces acting on the closed valve are transferred to the valve housing. The Dacron sewing ring is coated with thromboresistant Biolite Carbon on the surface to inhibit tissue overgrowth and prevent valve obstruction by hyperplastic intima. This new valve type was designed to reduce thromboembolism and mechanical dysfunction, the main problems of artificial heart valves. Comparison of different valve models is not yet standardized, and criteria for valve failure and valverelated complications differ from group to group. In describing the performance characteristics of this valve, we have used and modified definitions of the highly experienced Stanford group [3, 7, 81. Emphasis was placed on exact characterization of our patient sample to make our results comparable with those from other institutions and to differentiate between valverelated and patientrelated complications [a]. Tables 1 and 2 reflect specific problems of patients with different valve lesions. Whereas a high percentage of patients undergoing AVR suffer from angina, coronary heart disease, and syn Fig 9. Duromedics bileuflet prosthesis. copal attacks, patients undergoing MVR are characterized by a high rate of preoperative thromboembolism, lung and leg edema, and loss of sinus rhythm. Our overall hospital mortality of 6.25% is similar to those reported by other groups. Sethia and associates [9] report mortality between 7.0% and 10.4% for the Bjork Shiley prosthesis. Magilligan and colleagues [lo] found a 6.3% mortality rate for AVR and 8.3% for MVR with porcine bioprostheses. The Stanford group reports 10.6% for MVR (31 and 7.1% for AVR [7] with the Starr Edwards prosthesis. Results for the St. Jude Medical valve vary between 3.4% [ll] and 6.6% [12] overall. However, comparison of results must take into consideration the time of implantation and the recent improvements in cardiac surgery and myocardial protection. Furthermore, hospital mortality seems to be more a measure of the quality of care in an institution than of the prosthesis used [lo]. Our overall late mortality rate of 2.1% per patientyear also compares favorably with that of other groups (3.8% for the BjorkShiley valve [9], 2.5% for the St. Jude Medical valve 1111, and 7.3% for MVR with the Starr Edwards valve [3]), but these results have been accumulated for periods of up to 14 years. We agree with Magilligan s group [lo] that analysis of late deaths has not shown a significant difference among prosthetic valves. An indicator of valve performance more meaningful than the overall mortality is the proportion of deaths attributable to the valve [7]. Five of the 9 late deaths in our series (55%) were attributable to the valve, 3 were not valverelated cardiac deaths, and 1 was noncardiac. These results must take into account the maximum followup period of 24 months. For a longer period, 22% of all late deaths after MVR [3] and 18% after AVR [7] with the StarrEdwards valve have been reported to be valve related. We believe that the percentage of nonvalverelated deaths is increasing with the time of followup. One main aspect of the clinical evaluation of a new prosthesis is the distinction between problems related to a specific prosthesis and those related to valve replacement in general [13]. For valve selection, a more meaningful criterion than mortality rate is frequency of valverelated complications [14]. Our overall TE rate of 0.9% per patientyear is remarkably lower than that reported for the StarrEdwards valve. Miller and colleagues reported a 5.7% rate after MVR [3] and 2.7% after AVR [q. Schoevaerdts and associates [ 151 confirmed the higher complication rate for the StarrEdwards valve during the first postoperative years in their 20year experience. The St. Jude valve, which is the most similarly designed valve to the Duromedics bileaflet valve, but without an irrigated hinge mechanism, has a TE rate of 0.7% per patientyear in the aortic position and 3.6% per patientyear in the mitral position [16]. Bjork and Henze [17] report a TE rate of 0.7% after AVR and 4.2% after MVR, but these results are for patients in sinus rhythm. Atrial fibrillation was present before operation in only 2 of our patients with TE, and

6 308 The Annals of Thoracic Surgery Vol 44 No 3 September 1987 left atrial thrombi were found in none. As recently found by Mitchell and associates [8], the presence of atrial fibrillation was not predictive of increased risk of thromboembolism in a mixed patient population in which both StarrEdwards and xenograft aortic and mitral valves were used. These findings corroborate the results of Miller's group [3], who found the incidence of TE at 10 years to be identical, irrespective of whether the patient was in atrial fibrillation preoperatively and regardless of the presence of left atrial thrombi. However, in a collective review, Edmunds [5] reported a clearly increased risk of thromboembolism in the presence of atrial fibrillation. Contraindicated, omitted, poorly controlled, or withdrawn anticoagulation therapy substantially increases the incidence of TE in patients with mechanical valves [5]. Anticoagulation was insufficient in only 1 of our 4 patients with TE. The patient who died perioperatively was still heparinized at the time of death. The other 2 patients were well anticoagulated at the time of the'te event. Our PVE rate of 1.4% per patientyear is higher than the reported 0.3% for the BjorkShiley valve [9],0.5% for the St. Jude Medical valve [12], 0.5% for the Starr Edwards mitral valve prosthesis [3], and 0.9% for the StarrEdwards aortic valve prosthesis [7]. However, our data include 2 patients operated on for active I'VE (one with a mechanical valve and one with two bioprostheses) who had recurrence of PVE after operation. Excluding these patients from our sample, and thus figuring the rate of PVE developing after operation, would lower our rate of PVE to 0.7%, a figure closer to other reports. Several authors [18201 have suggested a more aggressive approach in the treatment of PVE based on early reoperation. Unfortunately, our 2 patients who died of I'VE during the followup period were not properly referred for reoperation. One additional patient was cured by conservative treatment. The value of the rate of PVE as a criterion for valve selection has been diminished by the findings of Rutledge and associates [21], who, in a risk analysis, found no effect on I'VE frequency and mortality by valve make, position, model, or number of valves implanted. These results were also confirmed by other authors [3, 221. Although the rate of valve failure was 1.8% in our study, there was only one event of thrombotic valve occlusion. Tissue ingrowth was found in another patient with PVE. No mechanical failure has been observed. Valve failure was caused mainly by factors unrelated to structural durability of the valve. The Stanford group reported a failure of 3.8% for MVR [3] and 2.2% for AVR [7] with the StarrEdwards valve. They have found the rate of valve failure to decline with followup. Clinical data during followup demonstrate the remarkable improvement in most patients. Although slight hemolysis was inferred from elevated LDH activity and decreased haptoglobin levels, none of our patients needed transfusion or other treatment. The degree of hemolysis was comparable to all disc or bileaflet valves in which the occluder is seated on the circumfer ence of the valve housing when the valve is closed. The lowest LDH values were found after AVR, indicating that hemolysis is not caused by shear stress acting on the erythrocytes while passing through the valve orifice, but mainly by the crush of blood cells between the valve components of the larger mitral valves [17]. Conclusion The Duromedics bileaflet valve offered good clinical results at our institution. Complication rates during the early period of followup have been in ranges reported for other mechanical prostheses. We therefore believe that wider use of this valve can be taken into consideration. Whether the new articulation mechanism can definitely lower the rate of TE and mechanical dysfunction cannot be answered at this time. Longer followup is indicated. References 1. Gersh BJ, Fisher LD, Schaff HV, et al: Issues concerning the clinical evaluation of new prosthetic valves. J Thorac Cardiovasc Surg 91:460, Hemex Scientific, Inc.: Clinical report Duromedics bileaflet valve. lo:l, Miller DC, Oyer PE, Stinson EB, et al: Ten to fifteen year reassessment of performance characteristics of the Starr 'Edwards Model 6120 mitral valve prosthesis. J Thorac Cardiovasc Surg 85.1, Baumgartner WA, Miller DC, Reitz BA, et al: Surgical treatment of prosthetic valve endocarditis. Ann Thorac Surg 35:87, Edmunds H Jr.: Thromboembolic complications of current cardiac valvular prostheses. Ann Thorac Surg 34:96, Moritz A, Klepetko W, Grabenwoeger F, et al: Two years experience with the Duromedics bileaflet valve prosthesis. Texas Heart Inst J 12:314, Miller DC, Oyer PE, Mitchell RS, et al: Performance characteristics of the StarrEdwards Model 1260 aortic valve prosthesis beyond ten years. J Thorac Cardiovasc Surg 88:193, Mitchell RS, Miller DC, Stinson EB, et a1 Significant patient related determinants of prosthetic valve performance. J Thorac Cardiovasc Surg 91:807, Sethia B, Turner MA, Lewis S, et al: Fourteen years experience with the BjorkShiley tilting disc prosthesis. J Thorac Cardiovasc Surg 91:350, Magilligan DJ, Lewis JW, Tilley 8, et al: The porcine bioprosthetic valve: twelve years later. J Thorac Cardiovasc Surg 89:499, Baudet EM, Oca CC, Roques XF, et al: A five and a half year experience with the St. Jude Medical cardiac valve prosthesis. J Thorac Cardiovasc Surg 90137, Arom KV, Nicoloff DM, Kersten TE, et al: Six years of experience with the St. Jude Medical valvular prosthesis. Circulation 72(Suppl 2):153, Bodnar E, Wain WH, Haberman S Assessment and comparison of the performance of cardiac valves. Ann Thorac Surg 34:146, Lefrak EA, Starr A: Cardiac valve prostheses. New York, AppletonCenturyCrofts, 1979, pp Schoevaerdts JC, Jaumin P, Lichtsteiner M, et al: Twenty year experience with the 6120 StarrEdwards valves in the

7 309 Klepetko, Moritz, KhunlBrady, et al: Duromedics Bileaflet Valve mitral position. J Thorac Cardiovasc Surg 9O(Suppl 4):26 35, Nicoloff DM, Emery RW, Arom KV, et al: Clinical and hemodynamic results with the St. Jude Medical cardiac valve prosthesis. J Thorac Cardiovasc Surg 82674, Bjork VO, Heme A: Ten years experience with the Bjork Shiley tilting disc valve. J Thorac Cardiovasc Surg 78331, Raychaudhury T, Cameron EW, Walbaum PR: Surgical management of prosthetic valve endocarditis. J Thorac Cardiovasc Surg 86:112, Kay PH, Oldershaw PJ, Lincoln JC, et al: The management of prosthetic valve endocarditis. J Cardiovasc Surg (Torino) 24:127, Baumgartner WA, Miller DC, Reitz BA, et al: Surgical treatment of prosthetic valve endocarditis. Ann Thorac Surg 35:87, Rutledge R, Kim BJ, Applebaum RE: Actuarial analysis of the risk of prosthetic valve endocarditis in 1598 patients with mechanical and bioprosthetic valves. Arch Surg 120:469, Rossister SJ, Stinson EB, Oyer PE, et al: Prosthetic valve endocarditis: comparison of heterograft tissue valves and mechanical valves. J Thorac Cardiovasc Surg 76795, 1978 BOOKS RECEIVED Biopsy Pathology of the Bronchi Elizabeth M. McDowell and Theodore F. Beak Philadelphia, Saunders, pp, illustrated, $65.00 This monograph covers interpretation of bronchial and transbronchial biopsies. Change of Heart. The Bypass Experience Nancy Yanes Hoffman New York, Harper and Row, pp, $7.95 (paperback) Twentyone patients who underwent bypass operations recount their experiences. On the cover are endorsements by surgeons who feel the book will be helpful to patients. Valvular Heart Disease. Second Edition Edited by James E. Dalen and Joseph S. Alpert Boston, Little, Brown, pp, illustrated, $68.00 Pathophysiology and diagnosis of heart disease are discussed. Echocardiographic Diagnosis of Cardiac Malformations Roberta G. Williams, Fredrick Z. Biman, and Stephen P. Sanders Boston, Little, Brown, pp, illustrated, $48.50 The authors focus on the anatomic diagnosis of cardiac malformations using ultrasonography. The book will be an important source of information on congenital heart disease, but physiologic evaluation with Doppler echocardiography is not covered. PatientControlled Analgesia Edited by M. Harmer, M. Rosen, and M. D. Vickers Boston, Blackwell Scientific, pp, illustrated This report on a symposium on patientcontrolled anesthesia will interest those concerned about control of postoperative pain. The editors point out that one of the major problems is the complexity of apparatus for administration and the need for their development. Temporary Cardiac Pacing Carl E. Bartechhi Chicago, Precept Press, pp, illustrated, $45.00 This monograph provides the basics for emergency temporary pacing. The author s goal is to increase the number of physicians knowledgeable in this technology. Medical Education. A Surgical Perspective Edited by Robert H. Bartlett, Gerald B. Zelenock, William E. Strodel, May L. Harper, and Jeremiah G. Turcotte Lexington, MA, Lewis, pp, illustrated, $69.95 Perusal of this book, the result of a symposium on surgical education, reveals no startling innovations and some real disappointments, such as endorsing the importance of National Board examination scores in the selection of residents. The information might be useful for faculty and residents and students who want to know how the system works. Progress in Cardiology Edited by Paul N. Yu and John F. Goodwin Philadelphia, Lea and Febiger, pp, illustrated, $35.00 The first part of this book is the report of a symposium on new therapeutic approaches to arrhythmias. Drug, electric, and ablative forms of therapy are discussed. A chapter on laser therapy and another on rheumatic fever and heart disease in India conclude the book.. Diagnostic Methods in Critical Care. Automated Data Collection and Interpretation Edited by William C. Shoemaker and Edward Abraham New York, Marcel llekker, pp, illustrated, $69.75 Diagnostic methods in the intensive care unit, including monitoring, imaging techniques, and computer applications, are covered in this multiauthored book, which is volume 9 of the Basic and Clinical Cardiology Series.