Infections in implantable cardioverter defibrillator patients

Salvage of Exposed Implantable Cardiac Electrical Devices and Lead Systems With Pocket Change and Local Flap Coverage

Erosion and exposure of pacemaker (PPM) and implantable cardiac defibrillator (ICD) devices are potentially dire complications, which have classically required the removal of the entire generator and lead systems. This study evaluates a series of cases wherein debridement, irrigation, pocket change, and local flap coverage were used for the successful salvage of indwelling leads after exposure and infection of implantable cardiac defibrillator devices. Patients with skin erosion, infection, and/or exposure of prepectoral infraclavicular cardiac defibrillator devices were treated over a 23-month period between June 2004 and April 2006. The surgical technique involved wide excision of the exposure site with a rhombic incision pattern, followed by removal of the generator unit and complete debridement of the peridevice capsule. Subclavian atrioventricular (AV) leads were preserved. The pocket was irrigated with antibiotic solution. A new pocket plane was selected and developed, and a new generator unit was implanted. A rhombic flap was developed and transposed to achieve tension-free closure over closed suction drains. Data were reviewed retrospectively. Six patients were treated, all male, mean age 66 years (range, 50 to 83 years). All patients presented with "new" exposure of the implantable generator within 48 hours. None demonstrated gross purulence, sepsis, or endocarditis. Initial gram stain was negative for bacteria in all cases, 1 (17%) grew sensitive Staphylococcus epidermidis species. Mean follow-up is 22 months (range, 8 to 31 months). One patient (17%) developed a hematoma, successfully treated by aspiration. Five patients (83%) were treated successfully, with no wound dehiscence, generator or lead exposure, or recurrence of infection. One patient (17%) developed drainage and exposure at a separate site (AV lead) at 10 months postoperative and required generator and lead explantation and site change to the contralateral anterior chest wall. In conclusion, in the absence of sepsis or gross infection, skin excision, pocket change, generator change with lead preservation, closed-suction drainage, and flap coverage for tension-free closure should be considered in the treatment of early ICD and PPM exposure.

Infections of implantable cardioverter-defibrillators: frequency, predisposing factors and clinical significance

The prognosis for patients with ventricular arrhythmias has improved dramatically with the aid of implantable cardioverter-defibrillators (ICDs). Although infection is a serious complication that frequently causes dysfunction and loss of ICDs, the frequency, predisposing risk-factors, and clinical and microbiological features are only partially understood. This study describes a retrospective review of 423 procedures in 278 patients with ICD primary implants and replacements performed at a tertiary-care hospital. Generators were placed in either a pectoral (68%) or abdominal (32%) site, and electrodes were placed transvenously in 97% of the patients. Most (95%) interventions were performed in a one-stage procedure. Infection developed with ten (2.4%) implanted devices. Four cases occurred within 30 days of surgery ('early infections') and six occurred > 1 month after surgery ('late infections'). In univariate analysis, factors associated with the development of an early infection were: two-stage surgery, a sub-costal approach, and abdominal generator placement. In patients with late infections, a significant association was found with trauma or decubitus ulcer in the generator area. Infection presented with local signs without systemic complications. Seven of the ten patients required complete removal of the system.

One Stage Side-to-Side Replacement of Infected Pulse Generators and Leads

Infected and contaminated cardiac pulse generators and leads must be removed entirely in order to effect a cure. We have shown through our experience with 68 consecutive cases that explantation of the offending system and replacement of a new device on the opposite side can be safely accomplished in one sitting--a side-to-side replacement--as long as there is appropriate case selection. There were no early or late infections of the new operative site.

Renal insufficiency and the risk of infection from pacemaker or defibrillator surgery

BACKGROUND

Pacemakers and implanted cardioverter defibrillator (ICD) infection rates are rising. Renal insufficiency impairs immune function and is known to increase the risk of infection following implantation of orthopedic hardware. The purpose of the current study is to characterize the risk factors for pacemaker and ICD infection and to evaluate the role of renal insufficiency in this complication.

METHODS AND RESULTS

A large (n = 4,856) single center experience with pacemaker and ICD procedures was reviewed. Of these, 141 were extractions of infected devices and 76 of these patients had been implanted in the Emory system and had preimplant creatinine information available for analysis. These cases were compared to 76 control patients undergoing device implantation matched by date of implant who had no infective complications. Demographic and clinical data from both groups were compared using both univariate and multivariate analysis. The overall rate of infection was 1.5%. Patients with device infection were more likely to have congestive heart failure (CHF), be diabetic, have generator exchanges, and to take warfarin than controls. There was no difference in the prevalence of coronary disease, atrial fibrillation, steroid use, or malignancy between the two groups. Elevated creatinine (Cr > or = 1.5 mg/dL) was much more frequent in patients with infection than in controls (38% vs 12%, odds ratio 4.6, P < 0.001). Moderate to severe renal disease (GFR < or = 60 cc/min/1.73 m2) was the most potent risk factor for infection, with a prevalence of 42% in infected patients versus 13% in controls (odds ratio of 4.8).

CONCLUSIONS

Renal insufficiency dramatically increases the risk of infection complicating pacemaker or ICD surgery. This association should be part of the risk-benefit consideration prior to device implantation. Additional study of more extensive perioperative antibiotic therapy in this subset of patients is warranted.

Animal study on surface-modified defibrillator systems: Indications for enhanced infection resistance

One of the most important problems with ICD systems is infection. The aim of this study was an in vivo evaluation of the efficacy of defibrillator systems in terms of infection resistance. The polyurethane leads were coupled with heparin and loaded with the antibiotic gentamicin, while the PGs were modified to release gentamicin. Group I was comprised of 10 pigs implanted with either a standard or a modified system for 2 weeks; group II was implanted during 4 weeks. The lead was inserted into the heart wall via the jugular vein. The other end was subcutaneously tunneled to the armpit where the PG was positioned. A cocktail of Staphylococcus aureus and epidermidis was injected at the site of the PG. Evaluation was performed macroscopically, by taking bacterial swabs during explantation and by microscopic processing. The results showed that 3 out of 5 modified defibrillator-systems in group I and 1-2 out of 5 in group II were judged as noninfected, whereas all standard systems were infected. Infection rates of the remaining modified defibrillators showed variances, as found with the standards, from slight to moderate to high, to even high/severe in group II (1x standard and 1x modified). With the modified systems, this may be related to production of humoral factors by an intensified early tissue reaction, as indicated by a swelling at day 6 at the site of the PG. When infected, whether or not modified, usually only Staphylococcus aureus was present. Spreading of infection seemed to occur by inoculation via blood, for example, based on the observation that group II in general showed an increase in infected fibrotic overgrowth in the heart, while infectious problems were low in the jugular vein. It is concluded that the modification at short term shows enhanced infection resistance. An increased infection rate already at 4 weeks, however, indicates that the modification may not hold in the long run. Special attention is needed concerning the more intense early tissue reaction.

Permanent explantation of implantable cardioverter defibrillators

Although ICD therapy is seen as an irrevocable mode of therapy in most patients, a small number of patients do have their devices permanently explanted. The long-term outcome in these patients has not been described. The purpose of this single center study was to evaluate the long-term outcome of patients whose ICD was explanted and not replaced and to propose clinical variables that can be considered when making the decision to discontinue therapy. Ten of 323 (3.1%) patients in our ICD registry had their devices permanently explanted or turned off between 1986 and December 1998. The devices had been in place for 39 +/- 31 months preexplant. No patient had received appropriate therapy prior to surgery, which was indicated for infection or lead fracture. All patients are alive and well 75 +/- 30 months postexplant with 1 (10%) patient requiring late reimplantation. We reviewed the English language literature describing ICD explanation without replacement. A total of 151 patients were reported in eight studies and were followed for up to 30 months postexplant. Excluding patients with terminal illness or heart transplantation 57.6% survived without reimplantation. In selected patients, after not using an ICD for a long period and when clinical circumstances justify, device therapy may be discontinued with some degree of safety.

Percutaneous extraction of transvenous defibrillator leads using the VascoExtor pacing lead removal system

In the implantable cardioverter defibrillator era the necessity for lead removal is not negligible. A specially designed extraction lead system for percutaneous removal of such leads is lacking, in contrast to the existing pacing lead extraction systems. We report the successful percutaneous extraction of four implantable cardioverter defibrillator leads in three patients because of lead malfunction using a novel pacemaker lead extraction system, the VascoExtor (VascoMed) system. Three leads were successfully removed in two patients using traction with special locking stylets from the superior approach. One lead was removed using the system's additional extraction tools through the femoral approach. There were no complications. This preliminary experience shows that the VascoExtor (VascoMed) pacemaker lead extraction system can also be used in implantable cardioverter defibrillator lead extraction safely and effectively. In addition to the locking stylets, adjunct percutaneous extraction tools may be needed in some cases.

Infections with nonthoracotomy implantable cardioverter defibrillators: can these be prevented? Endotak Lead Clinical Investigators

Nonthoracotomy ICDs are believed to be the best therapeutic modality for treatment of life-threatening ventricular arrhythmias. Little is known about the risk of infection with initial implantation of these devices. We studied the incidence, clinical characteristics, and risk factors associated with infections in 1,831 patients with nonthoracotomy ICD from the Endotak-C nonthoracotomy lead registry of Cardiac Pacemakers, Inc. A transvenous lead was implanted in 950 patients (51.9%) and a combination transvenous plus subcutaneous patch was used in 881 patients (48.1%). Nine preselected data variables were studied, and all investigators identified as having patients with infections were personally contacted. Infections occurred in 22 (1.2%) of 1,831 patients receiving this nonthoracotomy ICD system. The mean time to infection was 5.7 +/- 6.5 months (range 1-25 months). Staphylococci were isolated in 58% of patients with reported infection. The presence of a subcutaneous defibrillator patch system was associated with the development of infection. Six of 950 patients (0.63%) with a totally transvenous lead system developed infection versus 16 of 838 (1.9%) patients with a transvenous lead plus subcutaneous patch system configuration (P = 0.015, Chi-square test), with an unadjusted estimated odds ratio of 3.06 (CI 1.19-7.86). The risk of infection encountered with the nonthoracotomy ICD is low, estimated from our data to be 1.2%. Placement of a subcutaneous defibrillator patch appears to be an independent risk factor for development of infection.

Management of infected implantable cardiac defibrillators

BACKGROUND

The implantable cardiac defibrillator (ICD) was introduced clinically in 1980 for the management of ventricular arrhythmias.

METHODS

From January 31, 1989, through May 29, 1996, 329 ICD devices were implanted at Allegheny University Hospital, Hahnemann Division, Philadelphia, Pennsylvania. All device-related infections were examined.

RESULTS

Fifteen patients (5%) experienced infection of the generator component of the ICD. There were 14 male and 1 female patients with a mean age of 62 years (range, 38 to 79 years). All infections involved the generator with or without other component involvement. Complete removal of the system was performed in 7 patients, partial removal in 5, and the entire system was left intact in 3. In 4 patients (27%), further procedures were performed to remove additional infection. Three patients (20%) died during the hospital stay.

CONCLUSIONS

Infection of ICD devices is a devastating event. We favor complete removal of the ICD generator and all the components when possible. Partial removal of the ICD unit (ie, generator only) is reserved for patients in whom the risk of complete removal is too high and infection is confined to the generator only.

Undertreatment and overtreatment of patients with infected antiarrhythmic implantable devices

BACKGROUND

Infection of implantable defibrillators or pacemakers is a serious complication, reported with increasing frequency probably because of an increase in the total number of devices implanted due to a change in trends in the treatment of arrhythmias. This review is aimed to provide guidelines on how to deal with these infections and which method is most likely to be successful.

METHODS

This is a review of 38 patients with infected antiarrhythmic implantable devices under three different plans of therapy. There were 17 implantable cardioverter defibrillators and 21 pacemakers. In 27, infection occurred after primary implantation (15 pacers, 12 implantable cardioverter defibrillators), and in 11 after replacement (six pacers, five implantable cardioverter defibrillators). Three therapeutic plans were identified. Group I (n = 12) received intravenous antibiotics without removal of the antiarrhythmic implantable device, but with relocation to a different area or plane, and with or without the use of a topical irrigating-suction system. Group II (n = 19) had complete removal of the system, 2 weeks of intravenous antibiotics, and implantation of a new unit followed by 10 more days of antibiotics. Group III (n = 7) underwent complete removal, 6 weeks of antibiotics, implantation of a new unit, and another 6 or more weeks of antibiotic therapy.

RESULTS

Failure occurred in 100% of cases in group I. Groups II and III had complete clearing of infection and successful reimplantation of new systems with no recurring infections. Follow-up was 8 months to 5 years. Two deaths occurred, both in group I. Hospitalization for groups I and III was 104 days and 65 days, respectively, versus 22 days for group II. No deaths occurred in group II or III.

CONCLUSIONS

With an infected antiarrhythmic implantable device, immediate removal of the entire unit is recommended, followed by 2 weeks of intravenous antibiotics, implantation of a new system, and 10 more days of postoperative antibiotics. This regimen is sufficient to cure the problem. No attempts should be made to save an infected system from removal because it endangers the patient's life, prolongs hospitalization, increases costs, and most likely will fail.

The treatment of patients with infected implantable cardioverter-defibrillator systems

OBJECTIVE

The purpose of this study was to evaluate the treatment of patients with infected implantable cardioverter-defibrillator systems.

METHODS

Retrospective analysis was done of the cases of 21 patients treated for implantable cardioverter-defibrillator infection during an 11-year period.

RESULTS

Of 723 cardioverter-defibrillator implantations (550 primary implants, 173 replacements), nine (1.2%) were complicated by early postoperative device-related infections. Late infections developed in two patients 19 and 22 months, respectively, after implantation. Ten other patients were transferred to our institution for treatment of cardioverter-defibrillator infection. The time from implantation to overt infection was 2.2 +/- 1.3 months, excluding the two late infections. The responsible organisms were Staphylococcus aureus (9), Staphylococcus epidermidis (6), Streptococcus hemolyticus (1), gram-negative bacteria (3), Candida albicans (1), and Corynebacterium (1). All patients were treated with intravenous antibiotic drugs. Total system removal was done in 15 patients and partial removal in 2; in 4, the cardioverter-defibrillator system was not explanted. There were no perioperative deaths. A new implantable cardioverter-defibrillator system was reimplanted in 7 patients after 2 to 6 weeks of antibiotic therapy. Ten patients were treated without reimplantation (2 arrhythmia operation, 8 antiarrhythmic drugs). Four patients (3 patients without explantation and 1 with partial system removal) were treated with maintenance long-term antibiotic therapy. During a mean follow-up of 21 +/- 2.8 months, no patient had clinical recurrence of infection. One patient treated with antiarrhythmic drugs without system reimplantation died suddenly.

CONCLUSIONS

Infections that involve implantable cardioverter-defibrillator systems can be safely managed by removing the entire system with reimplantation after intravenous antibiotic therapy. In selected patients in whom the risk for system explantation is high and anticipated life expectancy is short, long-term antibiotic therapy to suppress low-virulence infections may represent an acceptable alternative.

Early cardioverter defibrillator infection: value of indium-111 leukocyte imaging

In the early postoperative period, it may be difficult to diagnose an infected implantable cardioverter-defibrillator system using anatomic imaging modalities such as computed tomography alone. We describe a case that illustrates the complementary physiologic role of indium-111-labeled leukocyte scintigraphy in identifying and defining the extent of early postoperative implantable cardioverter-defibrillator infection.

Erosion of internal cardioverter defibrillator pocket and migration of pulse generator into the peritoneal cavity

ICD therapy for life-threatening arrhythmias is well established. As more patients are treated, the incidence of recognized and new complications may increase. We report ICD pocket erosion and migration of the pulse generator into the peritoneal cavity in two patients.

Impact of implant techniques on complications with current implantable cardioverter-defibrillator systems

Implantable cardioverter-defibrillator (ICD) treatment has been in use since 1980 to prevent sudden cardiac death. The high efficacy of the original epicardial systems to terminate tachyarrhythmias was impaired by a substantial perioperative mortality and morbidity. The more "modern" transvenous ICD systems have shown a similar high efficacy in terminating ventricular tachyarrhythmias, but with a lower mortality and morbidity. As a background for discussing the impact on complications with present transvenous implantation techniques, the literature was reviewed. A large pacemaker series was used for comparison. Lead complications clearly related to design, material, or manufacture were not reviewed. The present review, covering 107 references over 40 years, gives support for the notion that in transvenously implanted ICD patients the incidence of acute and late complications related to implantation technique is now acceptable. The rate of hematomas, symptomatic thromboembolic complications, perforations, and to a certain degree infections could be improved, however. The major risk factors for implantation-related complications are discussed, and suggestions for future improvement are given.

Implantable cardioverter-defibrillator: another device to cover

The implantable cardioverter-defibrillator is a mechanical device developed to manage patients with life-threatening arrhythmias when pharmacologic control has failed or produced unacceptable side effects. It is a significant amount of foreign material with a generator pack (volume 113 to 145 cc, weight 197 to 235 gm) and two or three leads and patches that are inserted into or placed on the heart. Although it has worked very well in preventing premature death, there have been complications associated with the device itself. The most significant of these has been exposure and/or infection. We present three patients who have experienced this problem. Improved coverage has been accomplished by burying the implant beneath the rectus abdominis muscle in situations where skin and subcutaneous tissue alone have proved inadequate. By dividing one or two tendinous inscriptions and the anterior limb of the internal oblique fascia, a musculofascial pocket is created to contain the generator and lead wires. This provided satisfactory coverage in two of our three patients. The single failure resulted from external trauma to the abdominal wall.

Salvage of infected ICDs: management without removal

During the 7-year period from August 1986 to December 1993, 242 patients with malignant ventricular arrhythmias underwent 242 ICD implantations and 50 subcutaneous generator changes. Wound infections developed in 5 patients (1.7%): in 3 cases, after primary implantation (3/242 [1.2%]); and in 2 following a generator change (2/50 [4.0%]). This difference was not statistically significant. Infection developed at the generator pocket and became clinically manifest between 6 weeks and 40 months, postoperatively. Our treatment approach with the first patient consisted of simple debridement of the pocket and reimplantation of the existing generator. This led to recurrence, and the generator was safely explanted. In the remaining four patients, our approach has been that of local treatment, with wide debridement of the pocket, and placement of a closed irrigation system with continuous irrigation with a bacitracin, polymyxin, neomycin solution, and culture-specific antibiotic therapy. We have successfully controlled the infection and salvaged the generator with this approach in all four patients, who are all alive and well at a mean follow-up of 25.0 +/- 17.3 months with no recurrence. The good results obtained in these patients suggest that the concept of total explanation of the infected ICD should be reassessed.

Comparison of early and late complications in patients undergoing coronary artery bypass graft surgery with and without concomitant placement of an implantable cardioverter defibrillator

Previous studies have reported a significant morbidity and mortality associated with coronary artery bypass graft (CABG) surgery in conjunction with the placement of an implantable cardioverter defibrillator (ICD) with an epicardial lead system. In the absence of a control group, how significantly the component of concomitant placement of the ICD system contributes to these untoward outcomes remains unknown. The purpose of this study was to assess the short- and long-term complications in patients undergoing CABG surgery in conjunction with the placement of an ICD with epicardial leads and to compare these complications with those of patients who had only CABG surgery (control group). The study group (group A) consisted of 56 patients who underwent CABG surgery and placement of an ICD pulse generator with epicardial leads. A control group (group B) consisted of 56 patients who underwent CABG surgery only during the same time period. The two groups were matched for age, sex distribution, left ventricular function, surgical approach, number of bypass grafts per patient, bypass pump time, and length of follow-up period. The early mortality for group A was 7.1% versus 1.8% for group B (p > 0.05). The incidence of early morbidity (congestive heart failure, infection, supraventricular and ventricular arrhythmias) for groups A and B was similar (26.8% vs 25.0%, p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of complete system removal of infected cardioverter-defibrillators

We describe a case of device infection after implantable cardioverter-defibrillator implantation managed by removal of all hardware except a portion of the epicardial sensing electrodes. Recurrent septic complications developed until all residual foreign material was eliminated. Despite anecdotal reports of successful management without device removal, extraction of all hardware components should be considered standard treatment for this complication.

Optimizing defibrillation through improved waveforms

Defibrillation of the heart is achieved if an electrical current depolarizes the majority of the unsynchronized fibrillating myocardial cells. The applied current or the corresponding voltage described as a function of time is called the waveform. In pacing, to stimulate myocardial cells close to the electrode, a relatively low voltage is needed for a relatively brief duration. However, in defibrillation, approximately a 100-fold higher voltage is needed and achieved by the use of capacitors. The exponential voltage decay of a capacitor during its discharge determines the basic waveform for defibrillation. In an attempt to lower the energy needed for defibrillation, the steepness of the decay (different capacitances), the duration (fixed duration waveforms) or tilt (fixed tilt waveforms), or the initial polarity can be changed. Additionally, the polarity of the electrodes can be reversed during the discharge of the capacitor once (biphasic waveform) or twice (triphasic waveform). If two capacitors and defibrillation pathways are available, bidirectional defibrillation pulses can be delivered sequentially. In humans, the original standard waveform used with endocardial leads was a single monophasic pulse delivered by a 125-microF capacitor using the endocardial right ventricular electrode as cathode. It is now known that a reversal of the initial polarity and a reversal of polarity during capacitor discharge may significantly lower the energy needed for defibrillation, thereby preventing formerly frequent failures of defibrillation with endocardial lead systems. The use of sequential pulses showed no or only slight reductions of energy requirements and was abandoned due to the additional electrode needed. The use of a smaller capacitance (60-90 microF reduced maximum energy output but generally did not reduce energy requirements for defibrillation. However, with more efficient electrodes, smaller capacitances that will help to reduce the size of the defibrillator might be used. Thus, today defibrillation is optimized with respect to energy, capacitor size, and ease of implantation if an approximately 90-microF capacitor is used to deliver a biphasic pulse via a bipolar lead system using the right ventricular electrode as anode.

Cardioverter-defibrillator implantation in the catheterization laboratory: initial experiences in 48 patients

The exponential increase in cardioverter-defibrillator implantations has resulted in a need for safe implantations that do not require long waiting periods. We report intraoperative and follow-up results in 48 patients with ventricular tachyarrhythmias who underwent cardioverter-defibrillator implantation in the catheterization laboratory. Twenty-six (54%) patients had their first cardioverter-defibrillator implant (group 1), and 22 (46%) patients underwent pulse-generator replacement (group 2). In all patients, cardioverter-defibrillator implant or pulse-generator replacement was performed with the patient under general anesthesia. In 25 (96%) of 26 patients in group 1, cardioverter-defibrillator implantation was possible with a mean defibrillation threshold of 13 +/- 8 J. One patient had a defibrillation threshold of > 25 J, and therefore cardioverter-defibrillator implant was not achieved. This patient underwent epicardial device implantation 1 day later. Another patient in group 1 had vessel rupture (vena subclavia) intraoperatively. During a mean follow-up of 2 +/- 1 months, two patients died from congestive heart failure 2 and 4 months after device implantation. An infection occurred in one patient in group 2, 3 months after generator replacement. In conclusion, these data show that in the majority of patients cardioverter-defibrillator implantation in the catheterization laboratory is safe and has a low complication rate and therefore can generally be recommended.

Infections after cardioverter-defibrillator implantation: observations in 335 patients over 10 years

OBJECTIVE

To determine the incidence of infection after implantation of a cardioverter-defibrillator and the management of this complication.

SUBJECTS

335 consecutive patients who had a cardioverter-defibrillator implanted between January 1984 and December 1993.

MAIN OUTCOME MEASURES

Incidence of infection within the first month after implantation (early infection) and after the first month (late infection).

RESULTS

Infections associated with cardioverter-defibrillator devices occurred in 13 patients (3.9%) during a mean follow up of 22 (11) months. All patients had general signs of inflammation, fever (> 37.5 degrees C), and leucocytosis (> 10,000/ml) with or without purulent drainage. Five patients (38%) had infections during the first implantation, whereas eight patients (62%) had infections after replacement of the pulse generator. Early infection was observed in four patients (31%) and late infection in nine (69%). Incidence of infection was higher in patients who underwent epicardial cardioverter-defibrillator implantation (12/207 patients, 5.8%) than in those who received nonthoracotomy lead systems (1/125 patients, 0.8%) (P < 0.05). Infections were caused by staphyloccocus in 10 patients, pseudomonas in two patients, and streptococcus in one patient. The whole device had to be removed in all patients. During a mean follow up of 39 (29) months seven patients died: six of congestive heart failure and one of myocardial reinfarction.

CONCLUSIONS

Infection, one of the most serious complications after cardioverter-defibrillator implantation, is associated with increased morbidity and mortality. When infection occurs the system must be removed to avoid a fatal outcome.

Nonthoracotomy- versus thoracotomy-implantable defibrillators. Intention-to-treat comparison of clinical outcomes

BACKGROUND

Nonthoracotomy-implantable cardioverter/defibrillator (ICD) systems may represent a significant advance in the treatment of patients with life-threatening ventricular arrhythmias, but their merits relative to those of the well-established thoracotomy systems remain largely unknown. The objective of this study was to compare the short- and long-term clinical outcomes after attempted ICD implantation via a nonthoracotomy versus thoracotomy approach in similar groups of patients.

METHODS AND RESULTS

Between September 1990 and December 1992, 212 consecutive patients underwent attempted ICD system implantation without concomitant cardiac surgery at a single institution. Approach selection was not randomized but rather was based primarily on hardware availability. Primary comparisons of short- and long-term outcome were performed according to the "intention-to-treat" principle. Implantation was attempted via a nonthoracotomy approach in 120 patients (57%) and via a thoracotomy approach in 92 patients (43%). Prior cardiac surgery was more prevalent in the nonthoracotomy patients; otherwise, groups did not differ significantly in terms of prognostically relevant clinical characteristics. Nonthoracotomy implantation was successful in 101 patients (84%). After crossover to thoracotomy implantation (14 patients), the eventual success rate for ICD system implantation was 96% in the nonthoracotomy group. Thoracotomy implantation was successful in 89 patients (97%). Operative mortality was 3.3% in the nonthoracotomy and 4.3% in the thoracotomy groups (P = .73). Nonthoracotomy group patients were less likely to experience postoperative congestive heart failure (6% versus 16%; P = .02) or supraventricular arrhythmia (6% versus 18%; P = .004) and had significantly shorter postoperative intensive care and total hospitalization. Total hospital costs were significantly lower in the nonthoracotomy group ($32,205 versus $37,265; P = .001). After a follow-up of 16 +/- 9 months, there were 17 deaths in the nonthoracotomy group (none sudden) and 12 deaths in the thoracotomy group (1 sudden). One- and 2-year Kaplan-Meier survival probabilities were .87 (95% CI, .78 to .91) and .80 (95% CI, .68 to .88) in the nonthoracotomy group and .90 (95% CI, .82 to .95) and .87 (95% CI, .77 to .93) in the thoracotomy group (P = .56; log-rank test).

CONCLUSIONS

Nonthoracotomy ICD implantation is associated with reduced surgical morbidity, postoperative hospital care requirement, and hospital costs and has similar efficacy in preventing sudden death relative to the thoracotomy approach. From these nonrandomized data, it appears that a nonthoracotomy approach should be considered preferable in most patients requiring ICD therapy.

The usefulness of a stretch-polyester pouch to encase implanted pacemakers and defibrillators

This study was undertaken to assess the effects of enclosing permanent pacemaker and ICD pulse generators in a stretch-polyester pouch prior to implantation. Follow-up of 223 patients with oversized pacemakers and with ICDs and 344 with standard-sized pacemaker pulse generators showed that the pouch was effective in decreasing the frequency of pulse generator migration and extrusion.

Implantable cardioverter defibrillator patch erosion presenting as hemoptysis

Although the internal cardioverter defibrillator has prevented many premature deaths from lethal ventricular arrhythmias, some complications have occurred with its use. We present a patient who developed a fistula between the left ventricle and a bronchus, caused by erosion of the ventricular patch. The patient's presenting symptom was hemoptysis. Physicians caring for patients with these devices should be aware of this potential problem.

Troubleshooting new ICD systems

Advances in ICD technology have improved arrhythmia detection and termination, and the development of nonthoracotomy lead systems has reduced operative mortality and morbidity. Despite these important developments, patients with ICDs continue to experience untoward events that are usually attributable to lead failures, the effects of antiarrhythmic drugs, problems related to signal processing, or the need to modify the ICD program. It is incumbent on physicians who implant ICDs and monitor long-term therapy to appreciate the mechanisms by which these events occur, approaches needed to establish a diagnosis, and therapeutic interventions that can resolve problems associated with ICDs.

Complications of pacemaker-defibrillator devices: diagnosis and management

Treatment of resuscitated patients with implantable cardioverter defibrillators has become increasingly more common as a method for the prevention of sudden cardiac death. Major complications such as perioperative death (incidence 2% to 8%), infection (2% to 11%); and lead-related problems (3% to 27%) have been described in previous trials. In our experience with 140 patients, problems were related to leads (n = 11), the device (n = 2), pacing (n = 1), sensing (n = 13), and defibrillation function (n = 5). Additional problems that occurred during the perioperative period included infection (n = 11), hematoma, and seroma (n = 2). Thrombus formation along endocardial leads was observed in 13 of 62 (21%) patients. Different arrhythmias (n = 10), such as sinus tachycardia, atrial fibrillation, and nonsustained, slow or incessant ventricular tachycardia with shock delivery, were also detected. Surgical management (predominantly for the major problems) was used in 31 (48%) patients, drug treatment in 25 (39%), and reprogramming of the device in 24 (38%) patients. All of these problems can result in an increase in mortality rates. This article provides an overview of the complications of cardioverter defibrillator treatment and is based on both published data and our series.

Preperitoneal insertion of the HeartMate 1000 IP implantable left ventricular assist device

During a 16-month period, 12 consecutive patients underwent insertion of a HeartMate 1000 IP left ventricular assist device in a preperitoneal pocket that separated the device from the abdomen. All patients were in cardiogenic shock awaiting heart transplantation. Preoperatively, the mean cardiac index was 1.6 L.min-1.m-2, with 11 patients on intraaortic balloon pump support and 2 on extracorporeal membrane oxygenation. The pocket was formed below the rectus abdominis and internal oblique muscles and above the posterior rectus sheath. The pump fit easily in all patients. One patient died of progressive multiorgan failure. Four patients are still on support. Seven patients underwent successful transplantation after a mean duration of 55 days of support (mean pump index was 3.1 L.min-1.m-2 during support). One patient had driveline revision because of an exit site infection but had successful transplantation. The pump was explanted without difficulty at each transplant operation. All patients having transplantation are alive and well. Preperitoneal insertion of the HeartMate left ventricular assist device can be safely performed and may avoid problems posed by intraabdominal left ventricular assist device insertion.

Infection of implantable cardioverter defibrillator systems: a preventable complication?

In a consecutive series of 164 patients undergoing primary implantation of an implantable cardioverter defibrillator (ICD), two patients died in the hospital (1.2%) and early system infection developed in one patient requiring explantation of the device (0.61%). Late infection developed in one additional patient (0.61%) 7 months after transvenous ICD implantation, and was thought to be due to a recent intravascular catheterization. Symptomatic generator pocket hematomas developed in three patients, two of which were treated by simple evacuation and one with temporary generator explanation and subsequent reimplantation of the unit in a new pocket. No infection developed in these three patients during follow-up. Generator erosion without obvious system infection developed in a fourth patient. Guidelines for the prevention of infection in ICD systems are presented.

Implantable cardioverter defibrillator infection causing constrictive pericarditis

A case of severe constrictive pericarditis resulting from an indolent Pseudomonas aeruginosa infection of the automatic internal cardiac defibrillator is described. Total explanation of the device was attempted after nine months but was unsuccessful because of dense adhesions under the patch electrodes. The patient subsequently developed clinical and hemodynamic findings of constrictive pericarditis and a second desperate attempt to remove the patches resulted in operative death. Diagnostic modalities for detecting infection of the AICD are reviewed. As soon as there is infection involving any component, the entire lead system and pulse generator should be removed.

Infections involving implanted cardioverter defibrillator devices

Infection is one of the most serious complications in patients with an implanted cardioverter defibrillator. The diagnosis is facilitated by computed tomographic and radionuclide imaging. Infection may be caused by intraoperative contamination or hematogenous seeding. In view of the serious consequences, the emphasis should be on prevention of these events. Perioperative antibiotic prophylaxis is common practice but the utility of prophylactic antibiotic remote from surgery is questionable. Strict adherence to asepsis and a meticulous surgical technique are essential. Identification of risk factors in the individual patient allows a patient-tailored treatment policy that may add to infection prevention. If implant infection does occur, complete removal of the system is most successful.

Retrospective analysis of patients undergoing one- or two-stage strategies for myocardial revascularization and implantable cardioverter defibrillator implantation

Internal defibrillation leads were placed at time of coronary revascularization in 79 patients. In 34, an implantable cardioverter defibrillator (ICD) was placed simultaneously (group I). A two-stage strategy (selective implantation of the ICD in patients with postoperative spontaneous or inducible ventricular tachycardia [VT]) was followed in 45 patients (group II). Group I patients had failed more antiarrhythmic drug trials (2.9 +/- 1.6 vs 1.5 +/- 1.6; P = 0.02), including amiodarone (62% vs 20%; P less than 0.001). There were four operative deaths in each group. Postoperatively, VT was present in 27 group II patients (60%), 25 of whom received an ICD (two refused device implantation). Patients with postoperative VT had a lower left ventricular ejection fraction than those without VT (33 +/- 9 vs 47 +/- 16; P = 0.01). Actuarial survival at 1, 2, and 3 years was 88 +/- 6, 88 +/- 7, and 88 +/- 10 in group I; and 83 +/- 6, 76 +/- 7, and 76 +/- 11 in group II (NS). No patient without an ICD (based on the postoperative electrophysiological study [EPS]) died suddenly. Five patients (6%) had ICD system infection. Sudden death was largely prevented by either strategy, but relatively high rates of operative mortality and ICD system infection were observed. Prospective studies should identify patients more likely to benefit from one or another strategy.