Percutaneous management of superior vena cava syndrome in patients with cardiovascular implantable electronic devices

BACKGROUND

There is no consensus regarding the optimal management of cardiovascular implantable electronic device (CIED)-related superior vena cava (SVC) syndrome.

OBJECTIVE

We report our experience with transvenous lead extractions (TLEs) in the setting of symptomatic CIED-related SVC syndrome.

METHODS

We reviewed all TLEs performed at a high-volume center over a 14-year period and identified patients in which TLE was performed for symptomatic SVC syndrome. Patient characteristics, extraction details, percutaneous management of SVC occlusions, and clinical follow up data were analyzed.

RESULTS

Over a 14-year period, more than 1600 TLEs were performed. Of these, 16 patients underwent TLE for symptomatic SVC syndrome. The mean age was 53.1 ± 12.8 years, and 9 (56.3%) were men. Thirty-seven leads, with a mean dwell time of 5.8 years (range 2-12 years), were extracted. After extraction, 6 patients (37.5%) received an SVC stent. Balloon angioplasty was performed before stenting in 5 cases (31.3%). There was 1 major complication (6.3%) due to an SVC tear that was managed surgically with a favorable outcome. Eleven patients underwent reimplantation of a CIED. Over a median follow-up of 5.5 years (interquartile range 2.0-8.5 years), 12 patients (75%) remained free of symptoms.

CONCLUSION

Combining TLE with the percutaneous treatment of symptomatic SVC syndrome is a safe and viable treatment strategy.

Strategies for Transvenous Lead Extraction Procedures

Transvenous lead extraction (TLE) has undergone an explosive evolution since its inception as a rudimentary skill with limited technology and therapeutic options. Early techniques involved simple manual traction that frequently proved ineffective for chronically implanted leads, and carried a significant risk of myocardial avulsion, tamponade, and death. The morbidity and mortality associated with these early extraction techniques limited their application to use only in life-threatening situations, such as infection and sepsis. The past four decades, however, have witnessed significant advances in lead extraction technology, resulting in more efficacious techniques and tools, providing the skilled extractor with a well-equipped armamentarium. With the development of the discipline, we have witnessed a growth in the community of TLE experts coincident with a marked decline in the incidence of procedure-related morbidity and mortality, with recent registries at high-volume centers reporting high success rates with exceedingly low complication rates. Future developments in lead extraction are likely to focus on new tools that will allow for us to provide comprehensive device management, develop alternative systems for extraction training, and focus on the design of new leads conceived to facilitate future extraction.

Epicardial phrenic nerve displacement during catheter ablation of atrial and ventricular arrhythmias: procedural experience and outcomes

BACKGROUND

Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances.

METHODS AND RESULTS

PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon; however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients; however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months' follow up.

CONCLUSIONS

Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable.

ICD and CRT use in ischemic heart disease in women

Although the role of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) in improving outcomes in ischemic cardiomyopathy (ICM) has been described, the data regarding gender-based survival outcomes are limited. There is a higher preponderance of non-ischemic cardiomyopathy (NICM) in women, and most of the ICM literature is derived from sub-study analysis. This review summarizes the current body of literature on prognosis, pathophysiology, and the present clinical practice for device implantation in women with ICM.

Ventricular tachycardia in cardiac sarcoidosis: characterization of ventricular substrate and outcomes of catheter ablation

BACKGROUND

Cardiac sarcoid-related ventricular tachycardia (VT) is a rare disorder; the underlying substrate and response to ablation are poorly understood. We sought to examine the ventricular substrate and outcomes of catheter ablation in this population.

METHODS AND RESULTS

Of 435 patients with nonischemic cardiomyopathy referred for VT ablation, 21 patients (5%) had cardiac sarcoidosis. Multiple inducible VTs were observed with mechanism consistent with scar-mediated re-entry in all VTs. Voltage maps showed widespread and confluent right ventricular scarring. Left ventricular scarring was patchy with a predilection for the basal septum, anterior wall, and perivalvular regions. Epicardial right ventricular scar overlay and exceeded the region of corresponding endocardial scar. After ≥1 procedures, ablation abolished ≥1 inducible VT in 90% and eliminated VT storm in 78% of patients; however, multiple residual VTs remained inducible. Failure to abolish all inducible VTs was because of septal intramural circuits or extensive right ventricular scarring. Multiple procedure VT-free survival was 37% at 1 year, but VT control was achievable in the majority of patients with fewer antiarrhythmic drugs compared with preablation (2.1±0.8 versus 1.1±0.8; P<0.001).

CONCLUSIONS

Patients with cardiac sarcoidosis and VT exhibit ventricular substrate characterized by confluent right ventricular scarring and patchy left ventricular scarring capable of sustaining a large number of re-entrant circuits. Catheter ablation is effective in terminating VT storm and eliminating ≥1 inducible VT in the majority of patients, but recurrences are common. Ablation in conjunction with antiarrhythmic drugs can help palliate VT in this high-risk population.

Multicenter experience with transvenous lead extraction in arrhythmogenic right ventricular cardiomyopathy (ARVC)

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is becoming a more commonly diagnosed entity with frequent need for coincident implantable cardioverter defibrillator (ICD) therapy. Given predominant right ventricular disease with thinning of the wall, there is concern regarding the safety of transvenous lead extraction (TLE) in ARVC.

METHODS

We performed a retrospective study of consecutive patients with ARVC undergoing TLE of ICD leads at three high-volume centers. Patient and lead characteristics, indications, outcomes, and extraction sheath (ES) use were analyzed.

RESULTS

Between 1999 and 2012, more than 2,000 lead extractions were performed at the three centers. Of these, 11 patients underwent 14 extractions meeting inclusion criteria. Mean implant duration was 74.5 months (range 6-140). In 11 patients, a total of 22 leads (16 high-voltage and six pace-sense leads) were extracted in 14 procedures. The cohort was 50% male with a mean age of 45 years (range, 25-56) and mean ejection fraction 55 ± 13%. The majority (64%) of leads were extracted due to lead malfunction, three patients had an ICD lead removed for exit block, and three patients underwent TLE for infectious complications (two local, one systemic). ES assistance with laser or mechanical cutting sheaths was employed in the vast majority of cases (85.7%). All leads were removed completely. There were no major procedural complications. In five cases, lead reimplantation encountered low-amplitude R waves requiring multiple attempted lead positions before final successful implant.

CONCLUSIONS

This is the first reported series of TLE in ARVC patients. TLE can be performed safely and effectively in patients with ARVC by experienced operators at high-volume centers with a low complication rate.

Multicenter experience with transvenous lead extraction of active fixation coronary sinus leads

BACKGROUND/OBJECTIVE

Active fixation coronary sinus (CS) leads limit dislodgement and represent an attractive option to the implanter. Although extraction of passive fixation CS leads is a common and frequently uncomplicated procedure, data regarding extraction of chronically implanted active fixation CS leads are limited.

METHODS

We performed a retrospective cohort study of patients undergoing active fixation CS lead extraction at six centers. Patient and procedural characteristics, indications for extraction, use of extraction sheath (ES) assistance, and outcomes are reported.

RESULTS

Between January 2009 and February 2011, 12 patients underwent transvenous lead extraction (TLE) of Medtronic StarFix® lead (Medtronic Inc., Minneapolis, MN, USA). The cohort was 83% male with mean age 71 ± 14 years. Average implant duration was 14.2 ± 5.7 months (2.3-23.6). All leads but one were removed for infectious indications (67% systemic infection). At the time of explant, the fixation lobes were completely retracted in only one of the 12 cases and ES assistance was required for lead removal in all cases (58% laser, 25% cutting, 25% mechanical, and 25% femoral). The majority of cases required advancement of the sheath into the CS (75.0%) and often into a branch vessel (41.7%). One lead could not be removed transvenously and required surgical lead extraction. There were no major complications. Examination of the leads after extraction frequently revealed significant tissue growth into the fixation lobes.

CONCLUSIONS

Although TLE of active fixation CS leads can be a safe procedure in select patients and experienced hands, powered sheaths and aggressive techniques are frequently required for successful removal despite relatively short implant durations. This raises significant concern regarding future TLE of active fixation CS leads with longer implant durations.

The Evolution of Lead Extraction

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The Evolution of Lead Extraction

Prior to the introduction of successful intravascular countertraction techniques, options for lead extraction were limited and dedicated tools were non-existent. The significant morbidity and mortality associated with these early extraction techniques limited their application to life-threatening situations such as infection and sepsis. The past 30 years have witnessed significant advances in lead extraction technology, resulting in safer and more efficacious techniques and tools. This evolution occurred out of necessity, similar to the pressure of natural selection weeding out the ineffective and highly morbid techniques while fostering the development of safe, successful and more simple methods. Future developments in lead extraction are likely to focus on new tools that will allow us to provide comprehensive device management and the design of new leads conceived to facilitate future extraction. With the development of these new methods and novel tools, the technique of lead extraction will continue to require operators that are well versed in several methods of extraction. Garnering new skills while remembering the lessons of the past will enable extraction technologies to advance without repeating previous mistakes.

Cardioprotection: a new paradigm in the management of acute heart failure syndromes

The management of acute heart failure syndromes (AHFS) focuses primarily on improving hemodynamic function and alleviating symptoms. Emerging evidence has raised the possibility that patients with AHFS may be susceptible to progressive myocardial failure because of the accelerated loss of cardiac myocytes. Although there are circumstantial data to suggest that the choice of therapeutic agent may affect long-term outcomes in such patients, the responsible mechanism is not known. Activation of mitochondrial adenosine triphosphate-dependent potassium (K(ATP)) channels in cardiac myocytes is a potent cardioprotective mechanism. We studied cardiac myocytes in culture to determine whether levosimendan can protect against apoptotic cell death in response to oxidative stress, a stimulus that appears to mediate myocyte loss in response to hemodynamic overload and beta-adrenergic stimulation, conditions commonly encountered in acute HF. Levosimendan, at concentrations below the therapeutic range in humans, protected myocytes from hydrogen peroxide-induced apoptosis. This effect was prevented by K(ATP) channel inhibitors. The demonstration that levosimendan can oppose myocyte apoptosis via the activation of mitochondrial K(ATP) channels provides a potential mechanism by which this agent might protect cardiac myocytes during episodes of acute HF. Although the alleviation of symptoms should remain an important goal of therapy in acute HF, a therapeutic approach that includes a cardioprotective strategy may be able to exert a clinically meaningful benefit on disease progression. This speculation, if proved true, would mandate a fundamental paradigm shift in the acute management of acute HF.

Pressure Overload–Induced Myocardial Hypertrophy in Mice Does Not Require gp91 phox

Background— Reactive oxygen species (ROS) may mediate pressure overload–induced myocardial hypertrophy. NADPH oxidase may be involved in this process, because its expression and activity are upregulated by pressure overload and because myocardial hypertrophy caused by a subpressor infusion of angiotensin is attenuated in mice deficient in the gp91 phox catalytic subunit of NADPH oxidase.

Methods and Results— To test the role of NADPH oxidase–dependent ROS in mediating pressure overload–induced myocardial hypertrophy, we subjected transgenic mice lacking gp91 phox to chronic pressure overload caused by constriction of the ascending aorta. Contrary to our hypothesis, neither myocardial hypertrophy nor NADPH-dependent superoxide generation was decreased in gp91 phox -deficient mice after aortic constriction. Aortic constriction caused an exaggerated increase in p22 phox and p47 phox mRNA in gp91 phox -deficient mice.

Conclusions— These results indicate that gp91 phox is not necessary for pressure overload–induced hypertrophy in the mouse and suggest the involvement of another source of ROS, possibly an NADPH oxidase that does not require the gp91 phox subunit.

Oxidant stress in the vasculature

Vascular disease and vasomotor responses are largely influenced by oxidant stress. Superoxide is generated via the cellular oxidase systems, xanthine oxidase, and NADH/NADPH oxidases. Once formed, superoxides participate in a number of reactions, yielding various free radicals such as hydrogen peroxide, peroxynitrite, oxidized low-density lipoprotein, or hypochlorous acid. Numerous cellular antioxidant systems exist to defend against oxidant stress; glutathione and the enzymes superoxide dismutase and glutathione peroxidase are critical for maintaining the redox balance of the cell. However, the redox state is disrupted by certain vascular diseases. It appears that oxidant stress both promotes and is induced by diseases such as hypertension, atherosclerosis, and restenosis as well as by certain risk factors for coronary artery disease including hyperlipidemia, diabetes, and cigarette smoking. Once oxidant stress is invoked, characteristic pathophysiologic features ensue, namely adverse vessel reactivity, vascular smooth muscle cell proliferation, macrophage adhesion, platelet activation, and lipid peroxidation.