Clinical Management of the Infected Pacemaker

Transcription

1 Clinical Management of the Infected Pacemaker W. B. Firor, M.D., J. F. Lopez, M.D., E. M. Nanson, F.R.C.S., and M. Mori, M.D. T he totally implantable electronic pacemaker has proved to be a remarkable advance in the treatment of complete heart block [l], an arrhythmia with an otherwise gloomy prognosis [6]. However remarkable this advance may have been, pacemakers themselves have introduced new and unique problems, one of the most troublesome and potentially dangerous of which has been that of postoperative infection. A pacemaker with its associated system of electrodes is a large mass of foreign material for implantation within the human body. Despite its encasement in biologically inert material, that infection should occasionally occur and that it should be difficult to eradicate once present is understandable. CLINICAL EXPERIENCE Between 1962 and June, 1968, 96 pacemakers were implanted at the University Hospital, Saskatoon (Table 1). Our earlier experience has been reported previously [8]. Fortyeight of the pacemakers employed epicardial leads and were implanted at thoracotomy, and 48 employed a permanent transvenous electrode. Of this latter group, 25 were implanted in the cardiac catheterization laboratory and 23 were implanted in the operating theater utilizing a portable image intensifier" and full aseptic technique. Thirtysix units have required due to battery depletion or failure. All patients have been followed at regular intervals at a special pacemaker clinic by one of us (J. F. L.), the examinations there including electrocardiography and chest xray. Twelve infections requiring further surgical management have occurred in relation to the pacemaker unit2 following thoracotomy, 5 following implantation of permanent transvenous units, and 5 following of the battery unit alone (see Table 1). Three of these patients died, and infection was implicated in each. In 6 instances From the Departments of Surgery and Medicine, University of Saskatchewan, Saskatoon, Canada. Supported in part by the Saskatchewan Heart Foundation. Accepted for publication July 22, 'SiemensReinigerWerke, A. G. Erlangen, West Germany. VOL. 6, NO. 5, NOV.,

2 FIROR, LOPEZ, NANSON, AND MORI the offending organism was Staphylococcus aureus; in 2, S. albus; and in 1 the organism was mixed gramnegative. In 5 instances no organism could be isolated despite obvious and persistent clinical signs of infec Zion (Table 2). TABLE 1. INCIDENCE OF PACEMAKER INFECTION Operative No. of No. of Procedure Implantations Infections Thoracotomy 48 2 Transvenous Catheterization laboratory 25 5 Operating theater 23 0 Replacement of batteries 36 5 TABLE 2. CLINICAL AND BACTERIOLOGICAL FEATURES OF PACEMAKER INFECTION Interval Duration to Appear Possible Temporary Case No. & ance of Orga Antecedent Transvenous Procedure Infection nism Factor Pacing 1. Battery 1 mo. S.albus 2. Battery 1 wk. S. aureus Drain left in wound at time of of batteries 3. Transvenous 4 mo. No growth Catheter placed in cath. lab., batteries in operating room Thoracotomy 4 wk. S. aureus Thoracotomy 1 wk. S. auwus Battery 6 mo. S. aureus Battery 3 mo. No growth Transvenous 1 mo. No growth Transvenous 6 mo. No growth Battery 1 mo. Mixed gram negative Transvenous 3 mo. S. albus Transvenous 8 mo. S. aureus Dental extractions Chronic urinary tract infection. Remanipulation of catheter electrode Remanipulation of catheter electrode Chronic urinary infection Remanipulation of catheter electrodes 38 days 36 days 30 days 22 days 15 days 15 days 432 THE ANNALS OF THORACIC SURGERY

3 Infected Pacemakers The results of treatment in the earlier cases in this series were unsatisfactory. The infection persisted or was fatal, and as a result the program to be described in detail below evolved. This has now been applied in the last 6 consecutive cases, all of whom are now living, well, free of infection, and still under the control of an implanted pacemaker for periods of up to 18 months following the completion of treatment. CURRENT PLAN OF MANAGEMENT There are three guiding principles in the management of an infected pacemaker: 1. All foreign material (i.e., pacemaker and electrodes) must be removed before the infection can be eradicated. 2. A new permanent pacemaker must be implanted at a new and clean site, preferably not until after all infection has been eliminated. 3. Electrical pacing of the heart must be uninterrupted while the infection is under treatment. These three principles are occasionally in conflict, and this has led to our current concept of staged management of the infected pacemaker. The first stage consists of placement of a temporary transvenous catheter electrode percutaneously through the femoral vein." This will be connected to an external pacemaker? at the time of the second stage, namely, when the pacemaker and all electrodes are removed. This may require thoracotomy for the removal of sutured epicardial electrodes, but occasionally if infection has extended along the course of the electrodes to the heart, gentle traction on the cable may suffice for its removal and obviate thoracotomy. This was successfully done in 1 instance. Once all foreign material has been removed, the infection usually can be cleared quickly by usual means. As a general rule, it is best to leave the pocket previously occupied by the pacemaker open and to allow it to heal by secondary intention. After the infection has been cleared and the previous wound healed or clean, a new permanent pacemaker is implanted at a new location as far removed as possible from the previous site and the temporary catheter electrode removed. At this institution we currently favor the permanent transvenous pacemaker [4] of either the fixedrate or the demand type for the treatment of most types of complete heart block. The following case report illustrates both the futility of attempt *US. Catheter & Instrument Bipolar Pacemaker Electrode TMedtronic External Pacemaker 5800 or VOL. 6, NO. 5, NOV.,

4 FIROR, LOPEZ, NANSON, AND MORI ing local treatment of the infection and the successful applications of the above enumerated principles. CASE HISTORY Mrs. J. B., a 42yearold housewife from rural Saskatchewan, was initially seen for heart block at University Hospital in August, A Medtronic fixedrate pacemaker with epicardial leads was implanted at that time. Her postoperative convalescence was uneventful, and she remained well until August, 1965, at which time it was noted that the rate of the artificial pacemaker had fallen from its preset value of 74 beats per minute to 37 beats per minute. On August 29 the powerpack was replaced under local anesthesia, and once again her postoperative course was uneventful. In early February, 1966, dental extractions were done; about four weeks later an abscess around the powerpack developed which ruptured spontaneously. Culture of this showed the presence of S. aureus. The abscess cavity continued to drain intermittently through a sinus tract for the next several months despite antibiotics and local treatments. In August the patient noted the onset of intermittent fever, and she was readmitted on September 6, Three days later the pacemaker was removed under local anesthesia and the epicardial electrodes connected to an external pacemaker. On September 13 a temporary bipolar catheter electrode was introduced percutaneously through the right femoral vein and the external pacemaker transferred to it. On September 16 thoracotomy was done and the epicardial electrodes completely removed. A tract and pus were noted extending in the sheath adjacent to one of the electrode cables right up to the heart. Her postoperative course was surprisingly benign, and the infection cleared quickly. On October 17 the prior wound was clean enough to allow implantation of a permanent Medtronic transvenous pacemaker through the right external jugular vein. Her course since that time has been noteworthy only in that a subsequent battery was necessary in November, 1967, because of a gradually increasing rate. She has remained well and free of infection since. DISCUSSION We currently believe that implantation of a permanent transvenous pacemaker of either the fixedrate or the demand type is the treatment of choice for most patients with complete heart block. However, we do not believe that the cardiac catheterization laboratory or the xray department is a suitable locale for the performance of these operations; instead, we now perform them in the operating theater utilizing a portable image intensifier. Positioning the catheter under image intensification elsewhere in the hospital with subsequent transfer of the patient to the operating theater for implantation of the battery unit is undesirable, as has been pointed out by Kaiser et al. [7], and is probably worse from the point of view of contamination than is doing the entire procedure at someplace other than the operating room. We have had one such patient (early in our experience before our present policy was adopted) who subsequently developed infection (see Case 3, Table 2). Five infections have occurred in the 25 implantations done in the 434 THE ANNALS OF THORACIC SURGERY

5 Infected Pacemakers cardiopulmonary laboratory of this hospital. None have occurred in the 23 patients operated on since July, 1967, at which time the portable image intensifier became available to us. It is true that this latter group, being the more recent, contains a number of patients whose followup is relatively brief and therefore as a group has been at risk of acquiring infection for a lesser time. However, in the group operated upon in the catheterization laboratory, the longest interval from operation to the appearance of the first sign of infection was six months and the mean was four months (see Table 2). In the operating theater group, 2 have been followed longer than eight months and 8 longer than four months, the mean followup time being three months. Once infection has occurred in or around the pacemaker, removal of anything less than all of the foreign material will seldom lead to the cure of the infection, which usually extends for a variable distance along the track of the electrodes. There is usually little or no adherence between pacemaker electrodes and surrounding tissue, so that removal of only the battery unit and electrode accessible through the battery pocket will seldom suffice. Fortunately, continuous pacing through an external system using a temporary transvenous catheter electrode usually can be carried out long enough to allow the infection to be treated before implanting a new pacemaker at a different site (see Table 2). It was of some interest to us to note a quiescent period of weeks or months in a number of our patients between the time of operation and the appearance of infection. This suggests that the operative site may not have been colonized at the time of surgery and that this potentially vulnerable area may have been invaded at a later time by bloodborne organisms. Two of our patients had chronic urinary tract infections, and another infection developed six months postoperatively following dental extractions. The role of prophylactic systemic antibiotics in cardiovascular surgery remains controversial [3, 51, and it has not been our practice to administer them either on a shortterm or on a longterm basis to patients undergoing implantation of pacemakers. Our present data do not permit any conclusions concerning the use of antibiotics. However, in view of the recognized danger of late infections [2, 31 in the presence of intracardiac prostheses and in view of our own experience presented here, we are now considering administration of antibiotics to patients with implanted pacemakers at the time of dental extractions or genitourinary manipulations. SUMMARY AND CONCLUSIONS Experience with the management of 12 infections occurring at the site of implantation of a permanent pacemaker has been presented. VOL. 6, NO. 5, NOV.,

6 FIROR, LOPEZ, NANSON, AND MORI Three of these patients have died, and infection was implicated in each. Dissatisfaction with earlier methods of treatment has led to development of a new program which has been successfully applied to the last 6 consecutive patients, all of whom are now living and well. The fundamentals of this staged program are (1) removal of all foreign material from the patient, (2) continued electrical pacing through a temporary transvenous catheter electrode until the infection is clear and the wound clean, (3) subsequent implantation of a new permanent pacemaker at a different site. The current treatment of choice for most patients with complete heart block is the implantation of a permanent transvenous pacemaker. This procedure should be carried out in its entirety in an operating theater rather than in an xray department or a cardiac catheterization laboratory. The role of prophylactic antibiotics in the prevention of pacemaker infections has been briefly discussed. No firm conclusions can be drawn from the present data, but there is perhaps some wisdom in supplying antibiotics at the time of dental extraction or genitourinary manipulation. REFERENCES 1. Chardack, W. M., Gage, A. A., Federico, A. J., Schimert, G., and Greatbatch, W. Five years clinical experience with an implantable pacemaker. Surgery 58:915, Cohn, L. H., Roberts, W. C., Rockoff, S. D., and Morrow, A. G. Bacterial endocarditis following aortic valve : Clinical and pathological considerations. Circulation 33:209, Firor, W. B. Infection following openheart surgery, with special reference to the role of prophylactic antibiotics. J. Thorac. Cardiovasc. Surg. 53:371, Firor, W. B., and Goldman, B. S. Initial experience with the permanent implantable transvenous pacemaker: A report of 33 patients. Canad. Med. Ass. J. 96:144, Goodman, J. S., Schaffner, W., Collins, H. A., Battersby, E. J., and Koenig, M. G. Infection after cardiovascular surgery: Clinical study including examination of antimicrobial prophylaxis. New Eng. J. Med. 278: 117, Johansson, B. W. Complete heart block: A clinical, hemodynamic, and pharmacological study in patients with and without an artificial pacemaker. Actu Med. Scund. 180 (Suppl.):451, Kaiser, G. C., Willman, V. L., and Hanlon, C. R. Implantable pacemakers in heart block. Arch. Surg. (Chicago) 92:600, Nanson, E. M., Robinson, C. L. N., Merriman, J. E., Sellers, F., Horlick, L., Hayton, R. C., and Lopez, J. Three years' experience with implanted pacemakers. Canad. Med. Ass. J. 96:140, THE ANNALS OF THORACIC SURGERY