Phrenic Nerve Stimulation for the Treatment of Central Sleep Apnea: A Pooled Cohort Analysis

STUDY OBJECTIVES

Early evidence with transvenous phrenic nerve stimulation (PNS) demonstrates improved disease severity and quality of life (QOL) in patients with central sleep apnea (CSA). The goal of this analysis is to evaluate the complete prospective experience with PNS in order to better characterize its efficacy and safety, including in patients with concomitant heart failure (HF).

METHODS

Using pooled individual data from the pilot (n = 57) and pivotal (n = 151) studies of the remedē System in patients with predominant moderate to severe CSA, we evaluated 12-month safety and 6- and 12-month effectiveness based on polysomnography data, QOL, and cardiac function.

RESULTS

Among 208 combined patients (June 2010 to May 2015), a remedē device implant was successful in 197 patients (95%), 50/57 pilot study patients (88%) and 147/151 pivotal trial patients (97%). The pooled cohort included patients with CSA of various etiologies, and 141 (68%) had concomitant HF. PNS reduced apnea-hypopnea index (AHI) at 6 months by a median of -22.6 episodes/h (25th and 75th percentile; -38.6 and -8.4, respectively) (median 58% reduction from baseline, P < .001). Improvement in sleep variables was maintained through 12 months of follow-up. In patients with HF and ejection fraction ≤ 45%, PNS was associated with improvement in systolic function from 27.0% (23.3, 36.0) to 31.1% (24.0, 41.5) at 12 months (P = .003). In the entire cohort, improvement in QOL was concordant with amelioration of sleep measures.

CONCLUSIONS

Transvenous PNS significantly improves CSA severity, sleep quality, ventricular function, and QOL regardless of HF status. Improvements, which are independent of patient compliance, are sustained at 1 year and are associated with acceptable safety.

Extracellular Vesicles in the Blood of Dogs with Cancer-A Preliminary Study

Extracellular vesicles (EVs) are a heterogeneous population of submicron-sized structures released during the activation, proliferation, or apoptosis of various types of cells. Due to their size, their role in cell-to-cell communication in cancer is currently being discussed. In blood, the most abundant population of EVs is platelet-derived EVs (PEVs). The aim of this study was to estimate the absolute number and the origin of EVs in the blood of healthy dogs and of dogs with various types of cancer. The EV absolute number and cellular origin were examined by flow cytometry technique. EVs were classified on the basis of surface annexin V expression (phosphatidylserine PS+) and co-expression of specific cellular markers (CD61, CD45, CD3, CD21). The number of PEVs was significantly higher in dogs with cancer (median: 409/µL, range: 42-2748/µL vs. median: 170/µL, range: 101-449/µL in controls). The numbers of EVs derived from leukocytes (control median: 86/µL, range: 40-240/µL; cancer median: 443/µL, range: 44-3 352/µL) and T cells (control median: 5/µL, range: 2-66/µL; cancer median: 108/µL, range: 3-1735/µL) were higher in dogs with neoplasia compared to healthy controls. The estimation of PEV and leukocyte-derived EV counts may provide a useful biological marker in dogs with cancer.

Prognostic importance of serum troponin concentration in patients with an implanted cardioverter‑defibrillator admitted to the emergency department due to electric shock

BACKGROUND

High-energy implantable cardioverter-defibrillator (ICD) therapy may increase serum troponin (cTnI) concentration.   Aims: We aimed to assess an impact of cTnI concentration after ICD high-energy therapy on mortality.

METHODS

A total of 150 patients aged 64.2 +/- 12.8 years admitted to the Emergency Departments (EDs) due to at least one electrical shock during the last 24 hours with measured serum cTnI concentration at admission were included. Age, gender, comorbidities, shocks' numbers, therapy appropriateness, serum creatinine concentration, and left ventricular ejection fraction were noted for the retrospective analysis. Survival was obtained using the personal identification numbers (PESEL), on November 2018 until death or a period of three years had elapsed (1057 days).

RESULTS

cTnI concentration was increased in 92 (61.3%) patients. The mortality rate was related to age - HR: 1.04, 95% CI: 1.01-1.08, p = 0.026; increased cTnI concentration - HR: 2.88, 95% CI: 1.30-6.37, p = 0.009; diabetes - HR: 2.19, 95% CI: 1.09-4.39, p = 0.027; ischemic heart disease - HR: 2.96, 95% CI: 1.11-7.87, p = 0.030, serum creatinine concentration - HR: 2.17, 95% CI: 1.18-4.00, p = 0.013; LVEF (HR 0.95, 95% CI: 0.91-0.99, p = 0.009), and previous or current CABG or PCI (HR: 0.38, 95% CI: 0.15-0.96, p = 0.040 and HR: 0.29, 95% CI: 0.13-0.65, p = 0.003, respectively).

CONCLUSIONS

Increased mortality rate in patients with ICD shocks is multifactorial. Increased cTnI concentration at ED admission, but not the number of ICD shocks, is an independent marker of higher long-term mortality.

Epidemiology, clinical and cytological features of lymphoma in Boxer dogs

The aim of this study was to evaluate the epidemiology, clinical and laboratory characteristics of canine lymphomas as well as some aspects of treatment outcomes. The study was conducted on Boxer dogs with lymphoma diagnosed by cytology and immunocytochemistry (CD3 and CD79 alpha). During the study period, lymphoma was diagnosed in 63 Boxers; 86.8% were T-cell (based on the Kiel classification: small clear cell lymphoma, pleomorphic small cell lymphoma, pleomorphic mixed T-cell lymphoma, pleomorphic large T-cell lymphoma, lymphoblastic lymphoma/acute lymphoblastic leukaemia) and 13.2% were B-cell lymphomas (according to the Kiel classification: B-cell chronic lymphocytic leukaemia, centroblastic/centroblastic polymorphic lymphoma). Overall survival (OS) was significantly longer in dogs with low-grade than with high-grade lymphoma (median OS of 6.8 and 4.7 months, respectively; P = 0.024). OS was not influenced by WHO clinical stage, WHO clinical substage, presence of splenomegaly, early administration of glucocorticoids or the time from the first presentation to the beginning of chemotherapy. There are no significant differences in clinical and laboratory parameters between low-grade and high-grade lymphomas. Boxer dogs are predisposed to T-cell lymphoma, with a predominance of high-grade tumour, especially pleomorphic, mixed small and large T-cell subtype. It is possible that Boxer dogs may respond less favourably to chemotherapy than patients of other breeds.

Phrenic nerve stimulation in patients with central sleep apnea: a single‑center experience from pilot and pivotal trials evaluating the remedē System

BACKGROUND

Patients with central sleep apnea (CSA) have recently been shown to have improved sleep metrics and quality of life (QoL) with phrenic nerve stimulation (PNS).

AIMS

The aim of this study was to report the results of a partnership between cardiology, sleep medicine, and electrophysiology in a single clinical center as well as the enrollment, implantation, and follow‑up experience demonstrating both the safety and efficacy of PNS.

METHODS

This analysis included data from the pilot and pivotal trials investigating the effect of PNS using an implantable transvenous system in patients with CSA. We present our experience and data on the enrollment processes, implantation feasibility and safety, sleep indices, and QoL at 6 and 12 months of follow‑up.

RESULTS

Between June 2010 and May 2015, cardiology patients were prescreened and 588 of them were sent for in‑home sleep test. Ninety‑six patients were referred for polysomnographic studies, and 33 were enrolled and had an implant attempt, with 31 successfully receiving an implant. The apnea-hypopnea index was reduced in the pilot trial (mean [SD] of 48.7 [15.5] events/h to 22.5 [13.2] events/h; P <0.001) and in the pivotal trial (mean [SD] of 48.3 [18.8] events/h to 26.0 [21.9] events/h; P <0.001). Improvement in QoL was also observed.

CONCLUSIONS

We showed that PNS improved sleep metrics and QoL in patients with CSA, which is a result of multiple factors, including a comprehensive coordination between cardiology, sleep medicine, and electrophysiology. This ensures appropriate patient identification leading to safe implantation and full patient compliance during follow‑up visits.

How to implant a phrenic nerve stimulator for treatment of central sleep apnea?

Background

Central sleep apnea (CSA) is a breathing disorder caused by the intermittent absence of central respiratory drive. Transvenous phrenic nerve stimulation is a new therapeutic option, recently approved by the FDA , for the treatment of CSA.

Objective

To describe the technique used to implant the transvenous phrenic nerve stimulation system (the remedē System, Respicardia, Inc).

Methods

The remedē System is placed in the pectoral region, typically on the right side. A single stimulation lead is placed in either the left pericardiophrenic vein (PPV) or the right brachiocephalic vein (RBC). A sensing lead is placed into the azygous vein to detect respiration.

Results

In the remedē System Pivotal trial, 147 of 151 (97%) patients were successfully implanted with the system. Sixty‐two percent of stimulation leads were placed in the PPV and 35% in the RBC. Mean procedure time was 2.7 ± 0.8 hours and 94% of patients were free from implant‐related serious adverse events through 6 months.

Conclusion

In patients with CSA, transvenous phrenic nerve stimulation is an effective and safe therapy with an implant procedure similar to that of cardiac implantable electronic devices.

Seat belts-related behaviors in car drivers with cardiac implantable electronic devices

BACKGROUND

Seat belt use is the single most effective means of reducing fatal injuries in road traffic accidents. The presence of a cardiac implantable electronic device (CIED) might influence seat belt-related behaviors due to the physical proximity of the seat belt and left subclavian area in which the device is usually implanted. Understanding the underlying mechanisms of improper seat belt use may improve safety of these patients.

METHODS

We performed a prospective study using a structured questionnaire with 120 CIED recipients (age, 63.9 ± 10.9 years) attending a pacing outpatient clinic. All study participants were active drivers and predominantly male. The majority of patients (79%) had undergone high-energy device implantation.

RESULTS

We found that 18% of study participants do not fasten seat belts on a regular basis or use the seat belt in an atypical fashion (such as under the armpit). Moderate or high level of discomfort from the interaction between seat belt and CIED was present in 27%, while more than half (51%) were afraid of seat belt-induced CIED damage. In multifactorial analysis, we found the following independent predictors of improper seat belt use: (1) at least moderate level of discomfort at the CIED site (P = 0.02); (2) fear of CIED damage (P = 0.009); and (3) irregular seat belt use prior to CIED implantation (P = 0.037).

CONCLUSIONS

Improper seat belt-related behaviors are common in CIED recipients. They arise from previous habits and from CIED-related physical and psychological factors. Patients' education regarding the importance and safety of proper seat belt use is a priority.

Predictors of inappropriate shocks from implantable cardioverter-defibrillators

OBJECTIVE

Introduction: Inappropriate shocks in patients with an implantable cardioverter-defibrillator (ICD) are associated with significant psychological and physical consequences and increased long-term mortality. The aim: To assess predictors associated with inappropriate high-energy discharges of implantable cardioverter-defibrillators.

PATIENTS AND METHODS

Material and Methods: Retrospective data analysis of 150 patients aged 64.2±12.8 years (84.7% male) admitted to the Hospital Emergency Department due to at least one cardioverter-defibrillator discharge was performed. All of the discharges were inappropriate in the group of 33 patients, and in the group of 117 patients at least one discharge was appropriate. The following data: age, gender, concomitant diseases, type of ICD implantation (primary vs. secondary prevention), type of discharge, number of discharges, serum potassium, and sodium concentration were collected.

RESULTS

Results: Patients with only inappropriate discharges were younger, significantly more often had chronic atrial fibrillation, a significantly higher number of discharges, and ischaemic cardiomyopathy. Logistic regression analysis revealed that the occurrence of only inappropriate discharges was related to the number of discharges over three, the age of patients below 60 years, the serum sodium concentration between 135 mEq/L and 142 mEq/L, and the primary type of prevention of sudden cardiac death.

CONCLUSION

Conclusions: 1. Predictors of inappropriate discharges include: age, serum sodium concentration, and primary type of indications for cardioverter-defibrillator implantation. 2. Further research is necessary to determine the influence of disturbances in the sodium economy on the occurrence of appropriate and inappropriate interventions of implantable cardioverter-defibrillators.

Metastatic lymphadenomegaly in dogs - cytological study

Enlarged lymph nodes are frequently examined cytologically in dogs and metastatic lymphadenomegaly of various origin is a common cytological finding in these cases. In this study we aimed to examine epidemiological data, and to determine factors affecting the location of neoplastic metastases in the lymph nodes. Samples for cytological examination were obtained by fine-needle biopsy (FNB) of enlarged lymph nodes and stained with Giemsa solution. Cases meeting the following criteria were enrolled in the study: lymphadenomegaly detected in clinical examination, presence of primary mass confirmed by cytopathology or histopathology as a solid malignant tumour, and cytological diagnosis of metastatic tumour. Cytological pattern of lymph node involvement was classified as low, medium and massive. During study period 125 dogs met the eligibility criteria, with age ranged from 1.8 to 19 years. No sex predisposition to particular types of tumors was observed, except for adenocarcinoma which was diagnosed in females more often. Metastatic tumors were various in origin, with predominance of mast cell tumors, adenocarcinomas, and melanomas. Massive involvement predominated in all lymph nodes affected. Neoplastic lymphadenomegally is recognized usually in older dogs, with female predisposition related to dissemination of mammary cancers. Mast cell tumor, adenocarcinoma and melanoma are the most common causes of metastatic lymphadenomegaly, and in the vast majority of the cases massive lymph node involvement is observed.

[Patient with the intervention of an implantable cardioverter-defibrillator in a hospital emergency department]

OBJECTIVE

Introduction: Implantable cardioverter-defibrillators (ICD) improve prognosis in patients with malignant ventricular arrhythmias. Patients with ICD represent a significant proportion of all Emergency Department (ED) admissions. The number of these visits due to the high-energy therapy or antitachycardia pacing (ATP) delivered by the implanted cardioverter-defibrillator is constantly increasing. The aim: To present the prevalence and type of therapeutic interventions of an ICD in patients admitted to ED in 2014-2017 at two medical centers covering approx. 400 000 residents.

PATIENTS AND METHODS

Materials and methods: The patients' documentation was analyzed to find patients admitted to emergency department because of the suspicion of the ventricular arrhythmias' therapy delivered by ICD.

RESULTS

Results: In most cases adequate high-energy therapies due to life-threatening ventricular arrhythmias were the reason for hospitalization. We identified 126 patients aged 63.0±12.0 years, 108 (86&) of male and 18 (14&) of female. Among 171 ED admissions 6 were associated with ATP and 149 with high-energy therapy, 10 cases presented with VT without therapies, 5 with fantom shocks and in one case the patient had only a pacemaker but not ICD. The number of ICD shocks ranged from 1 to 108. Inadequate ICD discharges were found in 26 (17.4&) of high energy therapies.

CONCLUSION

Conclusions:1. The number of patients with ICD admitted to Emergency Department due to the initiation of high-energy or anti-tachyarrhythmic therapy has been steadily increasing in recent years. 2. In most cases, the reason for the admissions are adequate high-energy therapies, i.e. ICD discharges that disrupt the potentially life threatening arrhythmia. 3. Accurate medical history, the possibility of assessing the heart rate stored in the ICD memory during its intervention form the basis for establishing a plan of action in patients with ICD.

Cytodiagnostics of canine lymphomas - possibilities and limitations

Malignant lymphomas are one of the most common malignant tumours occurring in dogs. The basic method of lymphoma diagnosis in human, as well as in canine oncology is histopathology supported by immunohistochemistry. It was suggested that in veterinary medicine excisional biopsy of lymph node and histopathology should be considered only where the cytologic diagnosis is equivocal or needs to be confirmed. There are at least three basic reasons for which cytological examination ought to be accepted as a sufficient and reliable diagnostic method for lymphoma in dogs. Firstly, most dog owners consider the fine-needle biopsy as an acceptable non-harmful method of sample collection. Secondly, an increasing number of studies recommend cytology as an accurate test for diagnosing and subtyping canine lymphoma. Finally, the vast majority of canine lymphoma subtypes belong to 4-5 categories characterized by a typical cytological picture. Immunocytochemical staining of cytological smears gives new diagnostic possibilities, such as detection of markers better characterizing given growth or a potential goal for target therapy in individual cases (for example inhibitors of platelet-derived growth factor).

The biology of extracellular vesicles with focus on platelet microparticles and their role in cancer development and progression

Extracellular vesicles (EVs) are a heterogeneous group of structures which can be classified into smaller in size and relatively homogenous exosomes (EXSMs)—spherical fragments of lipid bilayers from inner cell compartments—and bigger in size ectosomes (ECSMs)—a direct consequence of cell-membrane blebbing. EVs can be found in body fluids of healthy individuals. Their number increases in cancer and other pathological conditions. EVs can originate from various cell types, including leukocytes, erythrocytes, thrombocytes, and neoplastic cells. Platelet microparticles (PMPs) are the most abundant population of EVs in blood. It is well documented that PMPs, being a crucial element of EVs signaling, are involved in tumor growth, metastasis, and angiogenesis and may participate in the development of multidrug resistance by tumor cells. The aim of this review is to present the role of PMPs in carcinogenesis. The biology and functions of PMPs with a particular emphasis on the most recent scientific reports on EV properties are also characterized.

The animal-dependent risk factors in canine T-cell lymphomas

Malignant lymphomas are one of the most common malignancies occurring in dogs; among them T-cell tumours are less commonly recognized. Recently, many authors have recommended cytology as a sufficient diagnostic method for canine lymphomas, especially if supported by immunocytochemistry or flow cytometry. The aim of the study was to characterize animal-dependent risk factors in canine T-cell lymphomas (TCLs) in Poland, including specific cytological subtypes. Determination of the type and subtype of the tumour was made based on the updated Kiel cytological classification adopted for dogs as previously described. Two breeds turned out predisposed to TCL (dog de Bordeaux and Boxer) while no predisposition to B-cell lymphoma could be evidenced. Dogs with low-grade lymphoma were significantly older than those with high-grade lymphoma.

Late Cardiac Tamponade as a Result of Parietal Pericardium Erosion

Late onset cardiac tamponade is a rare and particularly challenging (both from diagnostic and management perspectives) complication of intracardiac lead implantation. We present a case of a late tamponade leading to cardiogenic shock, which occurred 1,164 days after implantable cardioverter-defibrillator (ICD) implantation. Open repair revealed unusual and, to our knowledge, not yet reported mechanism of the disease. A pressure sore caused by an ICD lead was found in the parietal layer of pericardium with no visible damage to the visceral layer. Conservative management in the described clinical scenario could be fatal, thus awareness of this pathomechanism of tamponade is critical.

Epidemiological and morphological analysis of feline injection site sarcomas

Feline injection site sarcomas (FISS) are malignant neoplasms of mesenchymal origin which arise in sites of injections in cats. The prevalence is estimated between 1 in 1000 and 1 in 10 000 vaccinations in the United Kingdom. The aim of this study was to estimate the incidence of FISS in Poland and to analyse clinical aspects and histological and cytological features of injection site sarcomas. In our study the prevalence of FISS was 0.16% (16 FISS on 10.000 of cats) in feline patients in one of a veterinary surgery which conducts the general practice and 85 on 10.000 cats in a practice focused on veterinary oncology. The most typical microscopic features of FISS found in the present analysis were: the presence of perilesional scarring and inflammation, aggregates of lymphocytes at the tumour periphery, moderate but usually marked cellular pleomorphism and intralesional necrosis. The most typical cytologic features of FISS found in present study were: the presence of neutrophils, marked cellular pleomorphism, the presence of lymphocytes and macrophages, the presence of extremely large nuclei in the neoplastic cells, and high sample cellularity.

Large granular lymphoma in six cats

Large granular lymphomas (LGLs) comprise a specific group of lymphomas regardless of classifi- cation scheme. An LGL consists of cells that show less or more mature morphology, but typically neoplastic cells possess cytoplasmic azurophilic granules clearly visible during cytological examin- ation. The aim of the present study was to present clinical and cytological data on large granular lymphomas in cats and to analyses the therapeutic responses in treated cases. During the period from 2012 to 2014 six cats were as having large granular lymphoma. In one cat a nasal form of LGL was recognized, a systemic form was recognized in another cat, and in four cases an alimentary form was recognized. Cellular samples for cytopathology were collected from the cat with nasal cavity mass, from the enlarged mandibular lymph node and thoracic cavity from second cat, and in four cats from the abdominal mass during ultrasound-assisted fine-needle biopsy. Therapy was introduced in 5 of the 6 cats. In two cases palliative therapy with glucocorticoids was conducted, in two cases chemotherapy with COP protocol, and therapy with masitinib in one case. The median of survival time for cats treated with anticancer therapy was 9 months, the median of survival time for cats treated with glucocorticoids was 1.5 months. In conclusion, large granular lymphomas, especially the alimentary form, are a relatively common type of lymphoma in cats. Simple diagnostic methods such as clinical examination, imaging techniques and routine cytology are sufficient in majority of cases. Despite aggressive behavior and poor general prognosis, conventional chemotherapy lead to a good response in some treated cats regardless of anatomic form and histologic grade of malignancy.

Transvenous phrenic nerve stimulation for the treatment of central sleep apnoea in heart failure

AIMS

Periodic breathing with central sleep apnoea (CSA) is common in heart failure patients and is associated with poor quality of life and increased risk of morbidity and mortality. We conducted a prospective, non-randomized, acute study to determine the feasibility of using unilateral transvenous phrenic nerve stimulation for the treatment of CSA in heart failure patients.

METHODS AND RESULTS

Thirty-one patients from six centres underwent attempted transvenous lead placement. Of these, 16 qualified to undergo two successive nights of polysomnography-one night with and one night without phrenic nerve stimulation. Comparisons were made between the two nights using the following indices: apnoea-hypopnoea index (AHI), central apnoea index (CAI), obstructive apnoea index (OAI), hypopnoea index, arousal index, and 4% oxygen desaturation index (ODI4%). Patients underwent phrenic nerve stimulation from either the right brachiocephalic vein (n = 8) or the left brachiocephalic or pericardiophrenic vein (n = 8). Therapy period was (mean ± SD) 251 ± 71 min. Stimulation resulted in significant improvement in the AHI [median (inter-quartile range); 45 (39-59) vs. 23 (12-27) events/h, P = 0.002], CAI [27 (11-38) vs. 1 (0-5) events/h, P≤ 0.001], arousal index [32 (20-42) vs. 12 (9-27) events/h, P = 0.001], and ODI4% [31 (22-36) vs. 14 (7-20) events/h, P = 0.002]. No significant changes occurred in the OAI or hypopnoea index. Two adverse events occurred (lead thrombus and episode of ventricular tachycardia), though neither was directly related to phrenic nerve stimulation therapy.

CONCLUSION

Unilateral transvenous phrenic nerve stimulation significantly reduces episodes of CSA and restores a more natural breathing pattern in patients with heart failure. This approach may represent a novel therapy for CSA and warrants further study.

Electrocardiographic evaluation in patients with systemic scleroderma and without clinically evident heart disease

BACKGROUND

In patients with systemic scleroderma (SSc), clinically evident cardiac involvement is recognized to be a poor prognostic factor. The aim of the study was to evaluate electrocardiographic changes, parameters of heart rate variability (HRV), and heart rate turbulence (HRT) in patients with SSc without evident symptoms of heart disease.

METHODS

A group of 27 patients with SSc were subjected to standard electrocardiography (ECG) examination and 24-hour Holter monitoring. Analysis of HRV in time and frequency domains, HRT, and echocardiography were also performed.

RESULTS

Holter monitoring revealed a larger number of premature supraventricular contractions (PSVCs), as well as premature ventricular contractions (PVCs) in the patients with systemic scleroderma, as compared with the control group. Moreover, the SSc patients showed decreased parameters of time and frequency domains, as referred to the controls, especially during night hours. In four patients, abnormal HRT values were present. On echocardiography, only slight changes were found, however in five patients left ventricle diastolic dysfunction was diagnosed.

CONCLUSIONS

The noninvasive electrocardiographic methods seems to be useful for detecting early heart involvement in course of SSc and could be recommended for routine used in clinical practice. Significance of HRT analysis in patients with SSc needs further elucidation.