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Marko Turina

Publications and source records attributed to Marko Turina.

At least 19 recordsLinked to original sources
PubMed2005

Living patches engineered from human umbilical cord derived fibroblasts and endothelial progenitor cells.

OBJECTIVE: A major shortcoming in contemporary congenital heart surgery is the lack of viable replacement materials with the capacity of growth and regeneration. Here we focused on living autologous patches engineered from human umbilical cord derived fibroblasts and endothelial progenitor cells (EPCs) as a ready-to-use cell source for paediatric cardiovascular tissue engineering. METHODS: EPCs were isolated from 20 ml fresh umbilical cord blood by density gradient centrifugation and myofibroblasts were harvested from umbilical cord tissue. Cells were differentiated and expanded in vitro using nutrient media containing growth factors. Before seeding, cell-phenotypes were assessed by immuno-histochemistry. Biodegradable patches fabricated from synthetic polymers (PGA/P4HB) were seeded with myofibroblasts followed by endothelialization with EPCs. All patches were cultured in a perfusion bioreactor. A subgroup of patches was additionally stimulated by cyclic strain. Analysis of the neo-tissues comprised histology, immuno-histochemistry, extracellular matrix (ECM) analysis and biomechanical testing. RESULTS: Endothelial phenotypes of EPCs before seeding were confirmed by Ac-Dil-LDL, CD 31, von-Willebrand-Factor and eNOS staining. Histology of the seeded patches demonstrated layered viable tissue formation in all samples. The cells in the newly formed tissues expressed myofibroblast markers, such as desmin and alpha-SMA. The EPCs derived neo-endothelia showed constant endothelial phenotypes (CD 31, vWF). major constituents of ECM such as collagen and proteoglycans were biochemically detected. Stress-strain properties of the patches showed features of native-analogous tissues. CONCLUSIONS: Living tissue engineered patches can be successfully generated from human umbilical cord derived myofibroblasts and EPCs. This new cell source may enable the tissue engineering of versatile, living, autologous replacement materials for congenital cardiac interventions.

Biocompatible Materials↗
PubMed2005

Guidant Heartstring: initial experience in OPCAB surgery.

PURPOSE: The aim of this study was to evaluate the feasibility of the Heartstring hemostatic seal system for proximal anastomoses without the need for aortic side clamping in off-pump coronary artery bypass surgery . MATERIAL AND METHODS: Between May and November 2003, 50 proximal bypass anastomoses were performed with the Heartstring device in 29 consecutive patients (21 men, 8 women) with calcified aorta (assessed by transesophageal echocardiography/digital palpation). Mean patient age was 68 +/- 7 years. A mean of 1.7 anastomoses per patient was performed. Bypass patency was assessed by intraoperative flow measurements. Neurological outcome was graded in 4 severities. RESULTS: The learning curve was completed after deployment of approximately 10 devices. Crack of the seal prior to deployment occurred in 8 cases. No conversion to conventional side clamping was needed. No accidental stitching of the seal or wrapping of the suture around the seal stem occurred. Slight diffuse bleeding occurred with arterial pressure under 65 mm Hg. Bypass graft flow was 53.7 +/- 23.9 L/min. No perioperative ischemic events occurred, and there were no postoperative neurological complications. CONCLUSIONS: Proximal bypass aortic anastomoses can be performed safely without side clamping using the Heartstring hemostatic seal system. Anastomoses can be completed with no foreign material (stent) remaining.

Aged↗
PubMed2005

Geometrical model of the pulmonary root.

BACKGROUND AND AIM OF THE STUDY: The renaissance of the Ross procedure has attracted much attention to the clinical anatomy of the pulmonary valve. Within the reviewed literature which emphasizes the morphology of the pulmonary root, no detailed anatomy has been reported. The study aim was to describe the cardiosurgical-orientated anatomy of the pulmonary valve. METHODS: Morphometric measurements were made on 20 fixed normal pulmonary roots. The roots were fixed under diastolic pressure (5 mmHg) with closed leaflets. The distances between the commissures, and between the intervalvular triangles, were measured. The heights of the sinuses and of the intervalvular triangles were also defined. RESULTS: The mean (+/- SD) of each parameter was calculated. The distances of the right, left and anterior sinus commissures were approximately similar, as were the distances of the intervalvular triangles at the root base. The mean height of the left coronary sinus was maximal, followed by the right and anterior pulmonary sinuses. The left intervalvular triangle was highest, followed by the posterior and right intervalvular triangles. The difference between the height of the left sinus and right intervalvular triangle indicated a tilt angle of 16.26 degrees between the root base and sinotubular junction. CONCLUSION: Based on these measured parameters, a spatial geometrical model was constructed which clearly described the asymmetrical structure of the pulmonary root.

Adult↗
PubMed2004

Validation of Intracoronary Shunt Flow Measurements for Off-Pump Coronary Artery Bypass Operations.

Abstract Introduction: Intracoronary shunting is a useful, easy and inexpensive technique to maintain blood flow during off-pump surgery to lessen myocardial ischemia. Intracoronary shunts should provide a minimal flow for adequate myocardial protection. Material and Methods: Two commercially available shunts were used to measure flow from a bulb-size diameter of 1.00 mm to 3.00 mm (n = 10) in an in vitro setup. Shunts were perfused with Glycerin 47% solution at 37 degrees C. Inlet pressure was raised continuously from 0 to 160 mmHg in all intracoronary shunts. Results: In both groups (recipients of either type A shunt or type B shunt), mean pressure of 40 mmHg was necessary in shunts with diameter of 3.0 mm to provide a flow of approximately 50 mL/min. At mean pressure of 100 mmHg, a maximum flow of 126 mL/min was measured. Shunt B of 2.5-mm and 3.0-mm diameter showed similar flow patterns: 50 versus 52 mL/min at 40 mmHg and 98 versus 108 mL/min at 100 mmHg. Shunt A at 2.5-mm diameter showed 37 mL/min at 40 mmHg and 80 mL/min at 100 mmHg ( P =.01). Shunt B at 1.5-mm diameter required 75 mmHg for approximately 40mL/min and showed maximum flow of 51 mL/min at 100 mmHg ( P <.001). Only minimal flow was measured in 1.0-mm shunts of both groups. Conclusions: There is a clear pressure/flow correlation in 2.0-mm to 3.0-mm shunts with maximum flow of 126 mL/min. Type B shunt of 1.5-mm and 2.5-mm diameter showed significant better flow rates. The possible value of 1.0-mm shunts is only in stenting and facilitating anastomosis and to obtain better visibility during anastomosis.

Journal Article↗
PubMed2004

Umbilical cord blood derived endothelial progenitor cells for tissue engineering of vascular grafts.

BACKGROUND: A substantial limitation regarding present pediatric cardiac surgery is the lack of appropriate materials for the repair of congenital defects. To address this shortcoming, tissue engineering is a scientific field that aims at in vitro fabrication of living autologous grafts with the capacity of growth, repair, and regeneration. Here we focused on tissue engineered vascular grafts using human umbilical cord blood derived endothelial progenitor cells (EPCs), as a noninvasive cell source for pediatric applications. METHODS: EPCs were isolated from 20 ml fresh human umbilical cord blood by Ficoll gradient centrifugation and cultured in endothelial basal medium containing growth factors. After proliferation and differentiation cells were analyzed by immunohistochemistry and seeded onto three-dimensional (3D) biodegradable vascular scaffolds (porosity > 95%, n = 22). Twenty-four hours after seeding the vascular grafts were positioned into a pulse-duplicator-in vitro system and grown for 48 hours under biomimetic conditions. A second group was grown 6 days statically and an additional 6 days biomimetically. Controls were cultured statically. Analysis of the grafts included immunohistochemistry, histology, and scanning electron microscopy. RESULTS: Preseeding differentiated EPCs indicated constant endothelial phenotypes including acetylated low-density lipoprotein, cluster of differentiation 31, von Willebrand factor, and endothelial nitric oxide synthetase. Seeded EPCs established favorable cell-to-polymer attachment and proliferation into the 3D tubular scaffolds. Both conditioned and static cellular constructs demonstrated positive staining for cluster of differentiation 31, von Willebrand factor, and expression of endothelial nitric oxide synthase. CONCLUSIONS: Human umbilical cord derived EPCs indicated exceptional growth characteristics used for tissue engineering of vascular grafts. These cells demonstrated a constant endothelial phenotype and related functional features. Based on these results EPCs seem to be a promising autologous cell source with regard to cardiovascular tissue engineering, particularly for the repair of congenital defects.

Absorbable Implants↗
PubMed2004

Human umbilical cord cells for cardiovascular tissue engineering: a comparative study.

OBJECTIVE: Tissue engineering of viable, autologous cardiovascular replacements with the potential to grow, repair and remodel represents an attractive approach to overcome the shortcomings of available replacements for the repair of congenital cardiac defects. Currently, vascular myofibroblast cells represent an established cell source for cardiovascular tissue engineering. Cell isolation requires the invasive harvesting of venous or arterial vessel segments prior to scaffold seeding, a technique which may not be preferable, especially in pediatric patients. This study evaluates cells isolated from human umbilical cord artery, umbilical cord vein and whole cord as alternative autologous cell sources for cardiovascular tissue engineering. METHODS: Cells were isolated from human umbilical cord artery (UCA), umbilical cord vein (UCV), whole umbilical cord (UCC) and saphenous vein segments (VC), and were expanded in culture. All three expanded cell groups were seeded on bioabsorbable copolymer strips and grown in vitro for 28 days. Isolated cells were characterized by flow cytometry, histology, immunohistochemistry, proliferation assays and compared to VC. Morphological analysis of the seeded polymer strips included histology, immunohistochemistry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and uniaxial stress testing. RESULTS: UCA, UCV and UCC demonstrated excellent cell growth properties comparable to VC. Following isolation, all three cell groups showed myofibroblast-like morphology and characteristics by staining positive for alpha-smooth muscle actin (ASMA) and vimentin. Histology and immunohistochemistry of seeded polymers showed good tissue and extracellular matrix formation containing collagen I, III and elastin. TEM showed viable myofibroblasts and the deposition of collagen fibrils and progressive growing tissue formation, with a confluent surface, was observed in SEM. No difference was found among the mechanical properties of UCA, UCV, UCC and VC tissue engineered constructs. CONCLUSIONS: Tissue engineering of cardiovascular constructs by using UCA, UCV and UCC is feasible in an in vitro environment. Cell growth, morphology, characteristics and tissue formation were comparable between UCA, UCV, UCC and VC. UCC represent an attractive, readily available autologous cell source for cardiovascular tissue engineering offering the additional benefits of utilizing juvenile cells and avoiding the invasive harvesting of intact vascular structures.

Absorbable Implants↗
PubMed2004

Trajectory of coronary motion and its significance in robotic motion cancellation.

OBJECTIVES: To characterize remaining coronary artery motion of beating pig hearts after stabilization with an 'Octopus' using an optical remote analysis technique. METHODS: Three pigs (40, 60 and 65 kg) underwent full sternotomy after receiving general anesthesia. An 8-bit high speed black and white video camera (50 frames/s) coupled with a laser sensor (60 microm resolution) were used to capture heart wall motion in all three dimensions. Dopamine infusion was used to deliberately modulate cardiac contractility. Synchronized ECG, blood pressure, airway pressure and video data of the region around the first branching point of the left anterior descending (LAD) coronary artery after Octopus stabilization were captured for stretches of 8 s each. Several sequences of the same region were captured over a period of several minutes. Computerized off-line analysis allowed us to perform minute characterization of the heart wall motion. RESULTS: The movement of the points of interest on the LAD ranged from 0.22 to 0.81 mm in the lateral plane (x/y-axis) and 0.5-2.6 mm out of the plane (z-axis). Fast excursions (>50 microm/s in the lateral plane) occurred corresponding to the QRS complex and the T wave; while slow excursion phases (<50 microm/s in the lateral plane) were observed during the P wave and the ST segment. The trajectories of the points of interest during consecutive cardiac cycles as well as during cardiac cycles minutes apart remained comparable (the differences were negligible), provided the hemodynamics remained stable. Inotrope-induced changes in cardiac contractility influenced not only the maximum excursion, but also the shape of the trajectory. Normal positive pressure ventilation displacing the heart in the thoracic cage was evident by the displacement of the reference point of the trajectory. CONCLUSIONS: The movement of the coronary artery after stabilization appears to be still significant. Minute characterization of the trajectory of motion could provide the substrate for achieving motion cancellation for existing robotic systems. Velocity plots could also help improve gated cardiac imaging.

Animals↗
PubMed2004

Computational simulation of intracoronary flow based on real coronary geometry.

OBJECTIVE: To assess the feasibility of computationally simulating intracoronary blood flow based on real coronary artery geometry and to graphically depict various mechanical characteristics of this flow. METHODS: Explanted fresh pig hearts were fixed using a continuous perfusion of 4% formaldehyde at physiological pressures. Omnipaque dye added to lead rubber solution was titrated to an optimum proportion of 1:25, to cast the coronary arterial tree. The heart was stabilized in a phantom model so as to suspend the base and the apex without causing external deformation. High resolution computerized tomography scans of this model were utilized to reconstruct the three-dimensional coronary artery geometry, which in turn was used to generate several volumetric tetrahedral meshes of sufficient density needed for numerical accuracy. The transient equations of momentum and mass conservation were numerically solved by employing methods of computational fluid dynamics under realistic pulsatile inflow boundary conditions. RESULTS: The simulations have yielded graphic distributions of intracoronary flow stream lines, static pressure drop, wall shear stress, bifurcation mass flow ratios and velocity profiles. The variability of these quantities within the cardiac cycle has been investigated at a temporal resolution of 1/100th of a second and a spatial resolution of about 10 microm. The areas of amplified variations in wall shear stress, mostly evident in the neighborhoods of arterial branching, seem to correlate well with clinically observed increased atherogenesis. The intracoronary flow lines showed stasis and extreme vorticity during the phase of minimum coronary flow in contrast to streamlined undisturbed flow during the phase of maximum flow. CONCLUSIONS: Computational tools of this kind along with a state-of-the-art multislice computerized tomography or magnetic resonance-based non-invasive coronary imaging, could enable realistic, repetitive, non-invasive and multidimensional quantifications of the effects of stenosis on distal hemodynamics, and thus help in precise surgical/interventional planning. It could also add insights into coronary and bypass graft atherogenesis.

Animals↗
PubMed2004

Emergency stent-graft placement for hemorrhage control in acute thoracic aortic rupture.

OBJECTIVE: To report mid-term results of stent-graft (SG) implantation in acute thoracic aortic rupture as alternative to conventional open surgery with its associated high morbidity and mortality rates. METHODS: Out of a series of 69 patients undergoing thoracic aortic SG implantation since 1998, 24 (mean age 57+/-19 years, range 20-85-years-old) patients were treated on an emergency basis for hemorrhage control. The indication for SG placement was acute traumatic aortic rupture in 15 patients, type B dissection with contained rupture in 3 patients, penetrating aortic ulcer with periaortic hematoma in 3 patients, and thoracic aortic aneurysm rupture in 3 patients. Preoperative assessment was done by computed tomography (CT) scanning and echography. Patients were treated in the angiography suite by implantation of Excluder (n = 18) Talent (n = 4) Corvita (n = 1) and Vanguard (n = 1) self-expanding grafts. Local anesthesia was the most frequently used anaesthesiologic technique. RESULTS: Technical success rate of SG deployment was 100%. The early postoperative mortality was 12.5% (3 of 24). One patient suffered temporary paraplegia (4%). There was no intervention-related mortality during the mean follow-up of 34.1 months. Two secondary endoleaks were successfully treated with additional SG placement at 2 and 12 months postoperative, respectively. CONCLUSIONS: Emergency SG repair to control hemorrhage in patients with an acute thoracic aortic rupture is a less-invasive attractive and rational treatment option, especially if associated lesions or co-morbidity may interfere with the surgical outcome. Long-term follow-up results will be helpful to clarify procedure durability bounded by material failure and postoperative aneurysm or aortic wall remodelling.

Acute Disease↗
PubMed2004

Regional myocardial ischemia in hypertrophic cardiomyopathy: impact of myectomy.

OBJECTIVE: Chest pain is a common finding in patients with hypertrophic cardiomyopathy and can be observed in 40% to 50% of all patients. However, the pathogenesis of these ischemia-like symptoms is still unclear. METHODS: Twenty-two patients with hypertrophic cardiomyopathy and 15 controls underwent positron emission tomography for evaluation of regional myocardial perfusion and coronary flow reserve (hyperemic/baseline myocardial blood flow). Myocardial perfusion (mL/min/g) was measured using [(13)N]ammonia at rest and during hyperemia with dipyridamole (0.56 mg/kg intravenously). Regional coronary flow reserve was assessed in 3 planes (apical, midventricular, basal) in 4 regions (septal, anterior, lateral, inferior). Patients were divided into 2 groups: group 1 consisted of 11 patients treated with surgical myectomy (age 56 +/- 10 years) and group 2 consisted of 11 patients treated medically (age 53 +/- 13 years). RESULTS: Mean global coronary flow reserve was 3.87 +/- 0.92 in controls but 2.31 +/- 0.40 in operated (P <.001 vs controls) and 1.76 +/- 0.58 in medically treated patients (P <.001 vs controls, P <.05 vs operated). Similarly, septal coronary flow reserve was 4.19 +/- 1.22 in controls but significantly reduced in operated patients (2.26 +/- 0.48, P <.001 vs controls) and in medically treated patients (1.76 +/- 0.58; P <.001 vs controls). However, septal flow reserve was significantly higher in operated patients than in patients with medically treated hypertrophic cardiomyopathy (+37%, P <.05), mainly due to a reduced resting myocardial perfusion. CONCLUSIONS: Global and regional myocardial perfusion is reduced in patients with hypertrophic cardiomyopathy. However, myectomy may have a beneficial effect on septal perfusion and flow reserve. Thus, ischemia seems to play an important role in the symptomatology and pathophysiology of hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Genetic polymorphisms of apolipoprotein E4 and tumor necrosis factor beta as predisposing factors for increased inflammatory cytokines after cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass induces a rise in cytokines released by activated monocytes. The apolipoprotein E and the tumor necrosis factor beta polymorphisms are risk factors for atherosclerosis. The aim of the study was to investigate whether the genetic variants of apolipoprotein E (APOE*E4) and tumor necrosis factor beta (TNFB*A329G) affect cytokine release after cardiopulmonary bypass. METHODS: Thirty-eight patients underwent standard coronary artery bypass grafting procedures. Genotyping for APOE*E4 and TNFB*A329G was performed. Concentrations of interleukin 8 and tumor necrosis factor alpha were measured for 48 hours after surgery. Clinical data were collected prospectively. RESULTS: Fourteen patients (37%) carried the combination non-APOE*E4/wild-type TNFB*A329, 12 patients (32%) showed non-APOE*E4/TNFB*A329G, 9 patients (24%) had APOE*E4/TNFB*A329G, and 3 patients (7%) had APOE*E4/wild-type TNFB*A329. Total amount of tumor necrosis factor alpha was significantly higher in patients carrying the combination APOE*E4/TNFB*A329 than in those carrying non-APOE*E4/wild-type TNFB*A329 (P <.0001). Clinical data were similar except for intubation time and amount of transfusion, which were significantly increased in patients with genetic polymorphisms (P =.022, P =.033). CONCLUSION: Presence of TNFB*A329G polymorphism in addition to APOE*E4 variant is associated with significantly higher releases of interleukin 8 and tumor necrosis factor alpha, prolonged intubation, and increased transfusion relative to patients without genetic variants. Preoperative determination of APOE/TNFB genotypes in patients undergoing coronary artery bypass grafting may lead to additional perioperative measures to ameliorate systemic inflammatory response.

Aged↗
PubMed2004

Prevention of atrial fibrillation after cardiac valvular surgery by epicardial, biatrial synchronous pacing.

OBJECTIVE: Postoperative atrial fibrillation (AF) after cardiac surgery is a frequent complication after valvular surgery (30-60%). The purpose of this prospective, randomized study was to determine if biatrial synchronous pacing reduces postoperative AF after cardiac valvular surgery as compared to conventional therapy. METHODS: Eighty patients subjected to valvular surgery (52 men, age 66 +/- 10 years) were randomized to one of two groups: one group was treated with biatrial, synchronous pacing (BAP) for 72 h postoperatively (n=40) the other group received no atrial pacing (controls; n=40). All patients had one pair of epicardial wires attached to the right atrium. An additional electrode was placed to the left atrium in the BAP group. These patients were continuously paced at a rate of 10 beats per minute higher than the intrinsic rate starting immediately after surgery. All patients were monitored with full disclosure telemetry or Holter monitors to identify onset of AF. RESULTS: Eighteen of the 40 patients in the control group (45%) developed AF within the first 3 days postoperatively as compared to eight patients (20%) in the BAP group (P=0.02). No complications occurred associated with the placement, maintenance and removal of the atrial pacing electrodes. CONCLUSIONS: Temporary, biatrial synchronous pacing during the first 3 postoperative days is safe and has a significant rhythm-stabilizing effect in patients undergoing valvular cardiac surgery.

Aged↗
PubMed2004

Novadaq SPY: intraoperative quality assessment in off-pump coronary artery bypass grafting.

OBJECTIVES: Off-pump coronary artery bypass grafting may decrease operative morbidity when compared to on-pump bypass grafting; however, it is technically demanding and thus quality control is essential. This study assesses the clinical feasibility of a new, indocyanine green (ICG)-based imaging system (SPY; Novadaq Technologies; Toronto, ON, Canada) to monitor the quality of anastomoses and grafts in off-pump revascularization. SETTING: Thirty-eight consecutive patients undergoing nonemergent coronary artery bypass grafting without the use of extracorporeal circulation at two Swiss cardiac surgery clinics were included. On completion of bypass grafts, the quality of the grafts was assessed using the ICG-based imaging system. The imaging device comprises an 806-nm laser light source that is used to cause ICG to fluoresce and a near infrared-sensitive charged couple device videocamera that is used to capture the fluorescence images. ICG was administered through the central venous line, and images were acquired during the first pass of the ICG through the field of view. Graft flow (qualitative) and the quality of the grafts and anastomoses were assessed intraoperatively. RESULTS: Between March 2002 and September 2002, a total of 38 patients (26 men and 12 women; mean +/- SD age, 64.6 +/- 10.5 years; body mass index, 27.1 +/- 2.9) underwent surgery and imaging at two institutions. One hundred seven of 124 grafts (45 arteries and 62 veins) were analyzed. Seventeen grafts could not be assessed due to difficulties in positioning. The imaging system was easy to handle, and no adverse reactions to ICG were observed. Four of the 107 grafts imaged required revision (three anastomotic constrictions and one graft dissection). Each imaging sequence required approximately 1.25 to 2.5 mg of ICG. The images were equivalent to angiography without the need for radiographs and catheter insertion. In addition, the course of coronaries that would otherwise be difficult to locate in obese patients could be detected using the imaging system. Biochemical and ECG data demonstrated an absence of intraoperative or postoperative myocardial damage, and no liver enzyme elevation or renal dysfunction. CONCLUSIONS: This study supports the clinical utility of a ICG-based imaging system for the assessment of the quality of bypass grafts, which appears to be safe and simple to use.

Aged↗
PubMed2003

Impact of automatic adjustment of stimulation outputs on pacemaker longevity in a new dual-chamber pacing system.

INTRODUCTION: Automatic capture verification using the Autocapture (AC) feature enabled by paced evoked response detection and delivery of high energy back-up pulses intends to increase patient safety. Furthermore, adjustment of stimulation outputs can save energy and potentially improve pacemaker (PM) longevity. The purpose of this study was to evaluate the theoretical longevity of a new dual chamber PM with the integrated AC feature (Affinity DR, St. Jude Medical) in comparison to the longevity of a previous model from the same manufacturer without AC (Trilogy DR). METHOD: Affinity PMs were implanted in 16 patients and connected to a compatible lead with low polarization properties. AC was activated when the evoked response was significantly higher than the polarization voltage. Theoretical PM longevity was calculated with and without AC during follow-up. The measured and calculated values were compared to measurements in 19 patients, who consecutively received Trilogy-PMs during the same time period. RESULTS: In only one patient the evoked response was not adequate, and as a result, AC was not programmed. The calculated longevity of the Affinity-PMs 79 +/- 28 days after implantation was significantly higher in comparison to the Trilogy-PMs (Affinity-PMs: 8.9 +/- 1.2 years without and 9.5 +/- 1.1 years with AC; Trilogy-PMs: 6.5 +/- 0.8 years) (p < 0.005). CONCLUSION: The AC feature is an optional algorithm that can be activated in most patients and it significantly prolongs predicted battery longevity due to automatic adjustment of stimulation outputs.

Adult↗