Ventricular Arrhythmias in Left Ventricular Assist Device Patients-Current Diagnostic and Therapeutic Considerations.

Left ventricular assist devices (LVAD) are used in the treatment of advanced left ventricular heart failure. LVAD can serve as a bridge to orthotopic heart transplantation or as a destination therapy in cases where orthotopic heart transplantation is contraindicated. Ventricular arrhythmias are frequently observed in patients with LVAD. This problem is further compounded as a result of diagnostic difficulties arising from presently available electrocardiographic methods. Due to artifacts from LVAD-generated electromagnetic fields, it can be challenging to assess the origin of arrhythmias in standard ECG tracings. In this article, we will review and discuss common mechanisms, diagnostics methods, and therapeutic strategies for ventricular arrhythmia treatment, as well as numerous problems we face in LVAD implant patients.

ARTERIAL HYPEROXIA AND MORTALITY IN PATIENTS UNDERGOING VENOARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION.

ABSTRACT: Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can easily lead to supranormal oxygenation. The impact of hyperoxygenation beyond the early VA-ECMO support phase is unexplored. We sought to investigate its association with short- and long-term mortality. Methods: A total of 10,615 arterial blood gases of 179 patients undergoing VA-ECMO between 2013 and 2018 in our cardiosurgical tertiary center were analyzed for partial pressure of oxygen (PaO2) and its association with in-hospital, 90-day, and 1-year mortality. Patients were stratified into terciles (T) based on PaO2. Results: The median systemic PaO2 during VA-ECMO was 122 mm Hg (Q1-Q3, 111-158 mm Hg) and was significantly higher in 90-day nonsurvivors versus survivors (134 mm Hg [Q1-Q3, 114-175 mm Hg] vs. 114 mm Hg [Q1-Q3, 109-136 mm Hg]; P < 0.001). The incidence of mortality increased at all time points tested after VA-ECMO implantation along with the increasing terciles of PaO2. The lowest mortality rates were noted for patients with median PaO2 values of <115 mm Hg (T1), whereas patients with median PaO2 values of >144 mm Hg (T3) had the highest mortality rates. Bonferroni multiple testing analysis found the T3 of PaO2 to be a predictor of decreased 90-day survival in comparison with T1 (P < 0.001) and T2 (P = 0.002). Multivariable Cox regression analyses for in-hospital, 90-day, and 1-year mortality showed a significant association of the T3 compared with the T2 and the T1 of PaO2 to mortality across all endpoints. Conclusion: Hyperoxygenation during VA-ECMO might be associated with increased all-cause mortality. The results of our study further document the known toxicity of hyperoxygenation in general critical care patients and mark the need to focus specifically on VA-ECMO patients.

Troponin T and Survival following Cardiac Surgery in Patients Supported with Extracorporeal Membrane Oxygenation for Post-Cardiotomy Shock.

BACKGROUND: While troponin is an established biomarker of cardiac injury, its prognostic significance in post-cardiotomy cardiogenic shock patients supported by venoarterial extracorporeal membrane oxygenation (PCCS-VA-ECMO) remains unclear. OBJECTIVE: This study aimed to assess the correlation between early post-operative troponin T levels and both short-term and long-term mortality outcomes in this cohort. METHODS: We evaluated 1457 troponin T measurements from 102 PCCS-VA-ECMO patients treated from 2013 to 2018 at a specialized cardio-surgical and transplantation center. Emphasis was placed on troponin concentrations at 24-48 h post-surgery, post-VA-ECMO implantation, and peak troponin levels in relation to VA-ECMO weaning, as well as 90-day and one-year mortality. RESULTS: No significant association was observed between troponin T levels post-VA-ECMO implantation and 90-day mortality (median: 1338 ng/L for overall, 1529 ng/L for survivors vs. 1294 ng/L for non-survivors; p = 0.146) or between peak troponin levels and 90-day mortality (median: 3583 ng/L for overall, 3337 ng/L for survivors vs. 3666 ng/L for non-survivors; p = 0.709). Comprehensive multivariate models showed no correlation between troponin levels and various mortality endpoints. Notably, age, procedure urgency, type, LVEF pre-surgery, Euroscore II, prior cardiac arrest, and VA-ECMO duration were not linked with troponin release. Hemodiafiltration emerged as the strongest mortality risk factor [HR 2.4]. CONCLUSIONS: Isolated early Troponin T release and peak troponin T were not associated, while organ complications were linked with VA-ECMO weaning or short- and long-term prognosis. The results underscore the multi-organ implications of PCCS in determining survival.

Current applications and outcomes of venoarterial extracorporeal membrane oxygenation based on 6 years of experience: risk factors for in­hospital mortality.

INTRODUCTION: Data regarding venoarterial extracorporeal membrane oxygenation (VA ECMO) as a temporary circulatory support in cardiogenic shock (CS) for Central Europe are scarce. OBJECTIVES: The aim of the study was to disclose indications, in-hospital, and long-term (1-year) mortality along with risk factors. PATIENTS AND METHODS: The study is a retrospective investigation of patients who underwent VA ECMO for CS at a cardiosurgical tertiary center, from January 2013 to June 2018. A broad spectrum of pre- and postimplantation factors was tested using univariable analysis. RESULTS: A total of 198 patients met the inclusion criteria. The median (interquartile range) duration of support was 207 (91­339) hours, with no significant disparity among hospital survivors and nonsurvivors (P = 0.09). A total of 40.4% of patients died during ECMO support, while the joined in-hospital and 6-month mortality progressed to 65.2%, and 1-year mortality to 67.2%; 9% underwent a subsequent heart transplantation. Main adverse events were bleeding (76%), infection (56%), neurologic injury (15%), and limb ischemia (15%). Multiorgan failure was the most decisive risk factor of in-hospital mortality (odds ratio, 4.45; P <⁠0.001). Patients with postcardiotomy CS had a significantly lower out-of-hospital survival rate than the nonsurgical group (32.3% vs 45%; log-rank P = 0.037). CONCLUSION: The study showed survival benefit, despite frequent complications. The protocol focusing on proper candidate selection and timing can positively impact patient survival. Additional risk reduction can be achieved with a further increase of the team experience with ECMO.

Prevalence and management of driveline infections in mechanical circulatory support - a single center analysis.

BACKGROUND: Driveline infections in continuous-flow left ventricular assist devices (cf-LVAD) remain the most common adverse event. This single-center retrospective study investigated the risk factors, prevalence and management of driveline infections. METHODS: Patients treated after cf-LVAD implantation from December 2014 to January 2020 were enrolled. Baseline data were collected and potential risk factors were elaborated. The multi-modal treatment was based on antibiotic therapy, daily wound care, surgical driveline reposition, and heart transplantation. Time of infection development, freedom of reinfection, freedom of heart transplantation, and death in the follow-up time were investigated. RESULTS: Of 75 observed patients, 26 (34.7%) developed a driveline infection. The mean time from implantation to infection diagnosis was 463 (±399; range, 35-1400) days. The most common pathogen was Staphylococcus aureus (n = 15, 60%). First-line therapy was based on antibiotics, with a primary success rate of 27%. The majority of patients (n = 19; 73.1%) were treated with surgical reposition after initial antibiotic therapy. During the follow-up time of 569 (±506; range 32-2093) days, the reinfection freedom after surgical transposition was 57.9%. Heart transplantation was performed in eight patients due to resistant infection. The overall mortality for driveline infection was 11.5%. CONCLUSIONS: Driveline infections are frequent in patients with implanted cf-LVAD, and treatment does not efficiently avoid reinfection, leading to moderate mortality rates. Only about a quarter of the infected patients were cured with antibiotics alone. Surgical driveline reposition is a reasonable treatment option and does not preclude subsequent heart transplantation due to limited reinfection freedom.

Intra-operative fluorescein videoangiography-related nephrotoxicity in intracranial aneurysm surgery: Single center, observational cohort study.

OBJECTIVES: Intra-operative fluorescein video angiography (FL-VA) has been given increasing attention recently and several studies reported its high utility in neurovascular surgery. The aim of this study was to evaluate the safety of FL-VA in a prospective, single-center cohort of patients operated due to cerebral aneurysms. PATIENTS AND METHODS: This is an observational cohort study including 150 patients operated due to intracranial aneurysms. The study group consisted of 70 consecutive patients operated with the use of fluorescein video angiography. Post-operative acute kidney injury (AKI) occurrence as well as systemic adverse reactions were reported and further compared with 80 matched controls where FL-VA was not used. Statistical analysis was performed using non-parametric tests (Fisher's exact test). RESULTS: Post-operative AKI was observed in 17,1% of patients in the study group with only half presenting with acute functional impairment. All of these patients presented initially due to aneurysm rupture. Pre-existing renal dysfunction and hypertension occurred in 16,7% and 33,3%, respectively. No systemic complications following FL-VA were reported. When compared to matched controls, no statistically significant difference regarding AKI occurrence was observed between these two patient populations. CONCLUSION: Intra-operative fluorescein video angiography proved to have a good safety profile in our cohort. The results of this study suggest that post-operative acute kidney injury observed in patients with subarachnoid hemorrhage is not related to fluorescein use.

Predictors of Intraoperative Aneurysm Rupture, Aneurysm Remnant, and Brain Ischemia following Microsurgical Clipping of Intracranial Aneurysms: Single-Center, Retrospective Cohort Study.

BACKGROUND AND STUDY AIMS: Complete microsurgical clip occlusion of an aneurysm is one of the most important challenges in cerebrovascular surgery. Incorrect position of clip blades as well as intraoperative aneurysm rupture can expose the patient to serious complications such as rebleeding in case of aneurysm remnant and cerebral ischemia in case of occlusion of branching arteries or perforators. The aim of this study was to identify independent predictors of surgery-derived complications (aneurysm remnant and brain ischemia) as well as intraoperative aneurysm rupture in an institutional series of patients. MATERIAL AND METHODS: This is a single-institution, retrospective cohort study including 147 patients with 162 aneurysms that were selected for microsurgical clipping due to intracranial aneurysm in a 5-year period. Bivariate and multivariate analyses were performed to identify independent predictors among demographic, clinical, and radiographic factors. RESULTS: Increasing aneurysm size with a cutoff value at 9 mm (p = 0.009; odds ratio [OR]: 0.644) and irregular dome shape (p = 0.003; OR: 4.242) were independently associated with brain ischemia and aneurysm remnants that occurred in 13.6 and 17.3% of patients in our group, respectively. Intraoperative rupture was encountered in 27% of patients and its predictors were patient's age (p = 0.002; OR: 1.073) and increasing aneurysm size with a cutoff value at 7 mm (p = 0.003; OR: 1.205). CONCLUSION: Aneurysm size, patient's age, and irregular dome shape were the most important risk factors of aneurysm remnant, brain ischemia, and intraoperative aneurysm rupture in our series of patients. We were not able to define a cutoff value for patient's age, but our results showed that with increasing age the risk of intraoperative aneurysm rupture increased.

Intraoperative fluorescein video angiography in intracranial aneurysm surgery: single-center, observational cohort study.

The aim of this study was to compare the incidence of postoperative, surgery-related complications in patients where fluorescein video angiography (FL-VA) was performed with those operated without intraoperative verification. This is an observational cohort study including 97 patients who were selected for microsurgical clipping due to intracranial aneurysm. First 52 patients enrolled in the study were operated prior to introduction of fluorescein fluorescence in our surgical workflow. These patients were considered as controls. The study group consisted of 45 consecutive patients operated with the use of fluorescein video angiography and by the same surgical team. Outcomes in both groups were compared using non-parametric test (Mann-Whitney U). Intraoperative fluorescein video angiography revealed aneurysm remnant or inadvertent vessel occlusion in 17.8% of patients. Following clip reposition, a repeated FL-VA was performed to confirm restoration of blood flow and/or complete aneurysm obliteration. Intraoperative findings were later confirmed using computed tomography angiography (CTA). None of the patients in our study group developed surgery-related complications; whereas in the control group, aneurysm remnant was discovered in 7.7%, brain ischemia in 9.6% and both of the latter in 5.8% of patients. Difference in treatment-related outcome was statistically significant (p < 0.05). Intraoperative fluorescein video angiography successfully identified aneurysm residual and adjacent artery occlusion leading to excellent outcome following clip reposition.

Predicting conservative treatment failure in patients with lumbar disc herniation. Single center, case-control study.

OBJECTIVES: The aim of this study was to identify independent predictors of conservative treatment failure in patients presenting due to lumbar disc herniation-associated low back pain and sciatica. PATIENTS AND METHODS: This is a single institution, case-control study including 240 patients that were selected for microsurgical or conservative treatment due to lumbar disc herniation in a 2,5-year period. Bivariate and multivariate analyses were performed in order to identify independent predictors among demographic, clinical and radiographic factors. RESULTS: Statistically significant differences were observed between conservatively and surgically managed groups in bivariate analysis. Logistic regression models further revealed that leg paresthesia (p =  0,003; OR = 5,136) and percentage of spinal canal stenosis ratio (p < 0,001; OR = 1,055) had the strongest, independent correlation with conservative treatment failure in our cohort. Back-to-leg ratio did not reach statistical significance although it proved a strong correlation in bivariate analysis (p < 0,001, Cramér's V = 0,53). CONCLUSION: Increasing % canal compromise ratio (cut-off value 23%) and co-occurrence of leg paresthesia were the most important risk factors for surgery in our series of patients.

Results of open heart surgery in Jehovah's Witness patients. Single centre experience.

AIM: Evaluation the results in patients from the religious community of Jehovah's Witness (JW) undergoing open heart surgery at our institution. MATERIAL AND METHODS: Between September 2011 and March 2015, 21 patients with a religious background of the JW church underwent open heart surgery at our institution performed by the same surgical team. Mean age was 68.43 ±8.93 years. There were 13 (61.9%) female patients. Recombinant human erythropoietin was administered to every patient with a hemoglobin value < 12.0 g/dl. Nine patients undergoing isolated coronary artery revascularization were operated on without cardiopulmonary bypass. Seven patients underwent combined surgery and 5 patients underwent aortic valve replacement via ministernotomy. The mean follow-up time was 16.45 ±11.09 months (range: 1.67-44.3 months). RESULTS: Mean baseline hematocrit serum level was 40.15 ±3.34% (range: 34.5-46.1%). Perioperatively the hematocrit serum levels decreased to the mean level of 29.89 ±4.31% (range: 21.4-36.3%). The mean hematocrit value at discharge was 30.85 ±3.59% (range: 23.5-38.4%). One death was observed in the perioperative period. Five (24%) patients suffered from sternum wound infection requiring vacuum-assisted therapy. During the follow-up period 1 patient died due to a non-cardiac related cause. CONCLUSIONS: After careful preoperative preparation the results of open heart surgery in JW were very good, including combined procedures. The decrease of hematocrit serum levels significantly characterizing the postoperative period was highly acceptable in this series. Nevertheless, the number of sternum wound infections was a limiting factor for prompt postoperative recovery.

Pulsatile-flow mechanical circulatory support (MCS) as a bridge to transplantation or recovery. Single-centre experience with the POLCAS system in 2014.

INTRODUCTION: Mechanical circulatory support (MCS) is a recognised method of treatment for patients with end-stage chronic or acute heart failure. The POLCAS pulsatile-flow system has been used in our institution for 15 years. Currently, it is being widely replaced by continuous-flow mechanical circulatory support equipment of the second and third generations (HeartMateII, HeartWare). The MCS presented in this study is associated with a significant risk of complications and its use is increasingly considered controversial. The aim of the study was an evaluation of the results of treatment utilising the POLCAS MCS system at our institution in 2014. MATERIAL AND METHODS: The POLCAS system was implanted in 12 patients aged 16-63 years (42 ± 17 years) during a period of 12 months (from January to December, 2014). Full-blown cardiogenic shock was observed in all patients before MCS implantation. Four of the analysed patients (33%) required prior circulatory support with other devices: IABP (n = 2) or ECMO (n = 2). Episodes of cardiac arrest were reported in three patients; three other patients experienced serious arrhythmias, which accelerated the decision to implant MCS. The presented data was retrospectively obtained from the CliniNET system of the Institute of Cardiology. OpenOffice Calc spreadsheet was used for data analysis. RESULTS: Average MCS time was 41 days ± 25 (from 15 to 91 days). Survival until transplantation or explantation was 91.67%. The most frequent complications following the therapy were: cardiac tamponade or bleeding requiring an intervention - 25% (n = 3), renal failure requiring dialysis - 25% (n = 3), ischaemic stroke associated with the MCS - 16.6% (n = 2), bacteraemia - 16.6% (n = 2), and wound infection - 8% (n = 1). No malfunctions of the MCS system were reported. Early survival in patients who completed the MCS therapy, defined as discharge, amounted to 63.6% (n = 7). CONCLUSIONS: The POLCAS heart assist system is an effective method of treatment as a bridge to transplantation or recovery in patients with end-stage heart failure. Early survival after the treatment remains at a satisfactory level. The main problem is the large number of complications related to the therapy.