Cardiovascular implantable electronic device lead extraction: evidence, techniques, results, and future directions.

PURPOSE OF REVIEW: Cardiovascular implantable electronic devices are widely used to treat symptomatic arrhythmias, prevent sudden cardiac death, and improve symptoms and cardiac function. Continued population growth and expanding indications have resulted in a progressive increase in the number of cardiovascular implantable electronic device implantations. Mirroring this growth, an increasing number of leads require removal because of a variety of indications. Transvenous lead extraction continues to evolve with better techniques and risk-management strategies. This review highlights the indications, techniques, procedural outcomes, and future directions of arrhythmia device management and extraction. RECENT FINDINGS: Indications for extractions are reviewed in light of newly published data. Same day contralateral reimplantation has been shown to be safe in patients with localized pocket infection. Alternative extraction techniques, utilizing the femoral and internal jugular veins, provide additional routes for device removal as stand-alone procedures or in cases of difficult extraction via the subclavian vein. Preprocedural imaging to identify adherence sites and cardiac perforation can help to reduce complications. Routine capsulectomy at generator change does not seem to reduce the risk of device infection, and multiple trials are underway to assess other methods of reducing infections as part of a lead management strategy. SUMMARY: Improvement in technology, alternative routes of extraction and preprocedural imaging continue to add to procedural efficacy and reduce complication rates of lead extraction.

Cerebral microembolization after bioprosthetic aortic valve replacement: comparison of warfarin plus aspirin versus aspirin only.

BACKGROUND: No human physiological data exists on whether aspirin only is as effective as warfarin plus aspirin in preventing cerebral microembolization in the early postoperative period after bioprosthetic aortic valve replacement (bAVR). METHODS AND RESULTS: We prospectively enrolled 56 patients who had no other indication for oral anticoagulation, who underwent bAVR and received, in an open-label fashion, either daily warfarin (for INR 2.0-3.0) plus 81 mg of aspirin (n=28) or 325 mg of aspirin only (n=28). Cerebral microembolization was quantified at 4 hours (baseline) and at 1 month postoperatively, by recording 1-hour bilateral middle cerebral artery (MCA) microembolic signals (MES). Platelet-function analysis (PFA) of closure times (CT) on collagen was also used as a marker of platelet-dependent activation. Follow-up to 1 year was complete. Preoperative demographics and baseline platelet function were equivalent in both groups. There was no mortality, stroke, or transient ischemic attack at 1 year in either group. No significant differences were found in the proportion of patients with MES among those receiving warfarin plus aspirin versus aspirin only, at baseline (68% versus 82%, respectively; P=0.4) and at 1 month (46% versus 43%; P=1.0) after bAVR. The total MES and PFA were also equivalent between groups, at baseline and follow-up. CONCLUSIONS: Early after bAVR, the effects of these 2 antithrombotic regimens on cerebral microembolization and platelet function are equivalent. These data bring new mechanistic support to the premise that aspirin only may safely be used early after bAVR in patients who have no other indication for oral anticoagulation.

Reoperation of left heart valve bioprostheses according to age at implantation.

BACKGROUND: Evidence supporting the use of bioprostheses for heart valve replacement in young adults is accumulating. However, reoperation data, which may help guide clinical decision making in young patients, remains poorly defined in the literature. METHODS AND RESULTS: We examined the need for reoperation in 3975 patients who underwent first-time bioprosthetic aortic valve replacement (AVR) (n=3152) or mitral valve replacement (MVR) (n=823). There were 895 patients below the age of 60 years at bioprosthesis implant (AVR, n=636; MVR, n=259). The median interval to reoperation of contemporary, stented aortic bioprostheses was 7.74 years (95% CI 7.28 to 9.97 years) in patients less than 40 years, and 12.93 years (95% CI 11.10 to 15.76 years) in patients between 40 and 60 years of age. Multivariable risk factors associated with reoperation following bioprosthetic AVR include age (hazard ratio [HR] 0.94 per year, 95% CI 0.91 to 0.96, P<0.001) and concomitant coronary artery bypass grafting (HR 0.34, 95% CI 0.11 to 0.99, P=0.04). The median interval to reoperation of contemporary mitral bioprostheses was 8.11 years (95% CI 5.79 to 16.50 years) in patients less than 40 years, and 10.14 years (95% CI 8.64 to 11.14 years) in patients between 40 and 60 years of age. As for AVR, age (HR 0.96 per year, 95% CI 0.95 to 0.98, P<0.001) and concomitant coronary artery bypass grafting (HR 0.55, 95% CI 0.32 to 0.93, P=0.03) were associated with decreased reoperation risk following bioprosthetic MVR. CONCLUSIONS: These data constitute clinically relevant age-specific prognostic information regarding reoperation in young patients, who may wish to select a bioprosthesis at initial left heart valve replacement.

Very long-term survival implications of heart valve replacement with tissue versus mechanical prostheses in adults <60 years of age.

BACKGROUND: Several centers favor replacing a diseased native heart valve with a tissue rather than a mechanical prosthesis, even in younger adult patients. However, long-term data supporting this approach are lacking. We examined the survival implications of selecting a tissue versus a mechanical prosthesis at initial left-heart valve replacement in a cohort of adults <60 years of age who were followed for over 20 years. METHODS AND RESULTS: Comorbid and procedural data were available from 6554 patients who underwent valve replacement at our institution over the last 35 years. Of these, 1512 patients contributed follow-up data beyond 20 years, of whom 567 were adults <60 years of age at first left-heart valve operation (mean survivor follow-up, 24.0+/-3.1 years). Late outcomes were examined with Cox regression. Valve reoperation, often for prostheses that are no longer commercially available, occurred in 89% and 84% of patients by 20 years after tissue aortic and mitral valve replacement, respectively, and was associated with a mortality of 4.3%. There was no survival difference between patients implanted with a tissue versus a mechanical prosthesis at initial aortic valve replacement (hazard ratio 0.95; 95% CI: 0.7, 1.3; P=0.7). For mitral valve replacement patients, long-term survival was poorer than after aortic valve replacement (hazard ratio 1.4; 95% CI: 1.1, 1.8; P=0.003), but again no detrimental effect was associated with use of a tissue versus a mechanical prosthesis (hazard ratio 0.9; 95% CI 0.5, 1.4; P=0.5). CONCLUSIONS: In our experience, selecting a tissue prosthesis at initial operation in younger adults does not negatively impact survival into the third decade of follow-up, despite the risk of reoperation.

Central nervous system tuberculous abscess.

Central nervous system tuberculosis (CNS TB), uncommon in developed countries, still constitutes a significant proportion of brain mass lesions in developing countries. With the consistent increase in TB in the third world and the increase in immigration to Western countries, we can also expect to see an increase in the incidence of CNS TB. We present a case of cerebral TB in a patient two years after immigrating to Canada. A timely diagnosis of cerebral TB was even more complicated in this patient, who was known to have chronic migraine. There was no evidence of pulmonary involvement and the only abnormality on chest CT scan was mediastinal lymphadenopathy.

Late incidence and predictors of persistent or recurrent heart failure in patients with aortic prosthetic valves.

BACKGROUND: We examined factors associated with persistent or recurrent congestive heart failure after aortic valve replacement. METHODS: Patients who underwent aortic valve replacement with contemporary prostheses (n = 1563) were followed up with annual clinical assessment and echocardiography. The effect of demographic, comorbid, and valve-related variables on the composite outcome of New York Heart Association class III or IV symptoms or congestive heart failure death after surgery was evaluated with stratified log-rank tests, Cox proportional hazard models, and logistic regression. Factors associated with all-cause death were also examined. Prediction models were bootstrapped 1000 times. RESULTS: Total follow-up was 6768 patient-years (mean, 4.3 +/- 3.3 years; range, 60 days to 17.1 years). Freedom from congestive heart failure or congestive heart failure death was 98.6% +/- 0.3%, 88.6% +/- 1.0%, 73.9% +/- 2.3%, and 45.2% +/- 8.5% at 1, 5, 10, and 15 years, respectively. Age, preoperative New York Heart Association class, left ventricular grade, atrial fibrillation, coronary artery disease, smoking, and redo status predicted congestive heart failure after surgery (all P <.05). Larger prosthesis size and effective orifice area, both absolute and indexed for body surface area, were independently associated with freedom from congestive heart failure. Increased transprosthesis gradients were predicted by prosthesis-patient mismatch and were associated with congestive heart failure after surgery. Mismatch defined as an effective orifice area/body surface area of 0.80 cm(2)/m(2) or less was a significant predictor of congestive heart failure events after surgery, but mismatch defined as an effective orifice area/body surface area of 0.85 cm(2)/m(2) or less was not. Small prosthesis size and mismatch were not significantly associated with all-cause mortality. CONCLUSIONS: These analyses identify independent predictors of congestive heart failure symptoms and congestive heart failure death late after aortic valve replacement and indicate that prosthesis size has a significant effect on this cardiac end point, but not on overall survival after aortic valve replacement.

Late incidence and determinants of stroke after aortic and mitral valve replacement.

BACKGROUND: Stroke is a devastating complication in patients with prosthetic valves, but characterization of its late occurrence from a large cohort is lacking. METHODS: Three thousand one hundred eighty-nine adult patients who underwent a total of 3,576 operations for left-heart valve replacement were managed with contemporary anticoagulation guidelines and prospectively followed in a dedicated clinic. Total follow-up was 20,096 patient years. Bootstrapped survival analysis was used to determine the impact of patient and valve related factors on the incidence of stroke. RESULTS: Most strokes were embolic. Linearized embolic stroke rates were 1.3% +/- 0.2% per year for aortic bioprostheses, 1.4% +/- 0.2% per year for aortic mechanical valves, 1.3% +/- 0.3% per year for mitral bioprostheses, and 2.3% +/- 0.4% per year for mitral mechanical valves (p = 0.002, vs other implant types). Age more than 75 years, female gender, and smoking were independent risk factors after aortic and mitral valve replacement. Atrial fibrillation, coronary disease, and tilting-disc mechanical prostheses were independent predictors of embolic stroke after aortic valve replacement. Preoperative left ventricular (LV) dysfunction was an independent risk factor in patients with mitral prostheses. Primary operative indication, diabetes, redo status, or the presence of two prosthetic valves were not associated with an increased hazard. The addition of acetyl salicylic or dipyridamole to warfarin anticoagulation did not significantly lower embolic stroke risk in patients with mechanical prostheses. CONCLUSIONS: Approximately 20% of patients with valve prostheses have an embolic stroke by 15 years after valve replacement. Some risk factors such as the avoidance of smoking, mitral mechanical prostheses, aortic tilting-disc valves, and proceeding to mitral surgery before LV dysfunction occurs are potentially modifiable.