25th anniversary of the Department of Cardiac Surgery at the University Medical Center Maribor: advancing hearts, changing lives : A quarter century of commitment.

In 1996, Slovenia witnessed a profound transformation in its cardiac care landscape with the establishment of the Department of Cardiac Surgery at the University Medical Centre Maribor. This momentous milestone heralded the birth of the nation's second heart surgery center revolutionizing cardiovascular care accessibility. Today, the Department of Cardiac Surgery stands as a regional hub, delivering specialized cardiac surgical services to Slovenia's northeastern region and beyond. Its unwavering commitment to excellence, patient-centered care, and adherence to international guidelines reflects its dedication to providing top-tier cardiac care. As the department commemorates its 25th anniversary, this article offers a reflective overview of its establishment, development, growth and future trajectory for further development in an ever-changing era of cardiovascular medicine. The article also highlights the department's active involvement in international collaborations, scientific research, medical education, and innovations in minimally invasive cardiac surgery.

Veno-arterial extracorporeal membrane oxygenation for post-infarction ventricular septal defect in a low-volume center.

Managing patients with post-ischaemic ventricular septal defects (VSD) and postcardiotomy cardiogenic shock can be extremely challenging in a low-volume cardiac surgery unit. We present a case of a 68-year-old patient who received veno-arterial extracorporeal membrane oxygenation support due to cardiogenic shock after VSD repair. The patient was successfully weaned off support after 86 h. In the postoperative period, mediastinitis occurred, and negative pressure wound therapy was instituted.

Sternal Reconstruction Using 3D-Printed Titanium Custom-Made Prosthesis for Sternal Dehiscence After Cardiac Surgery.

Sternal dehiscence is an important complication that increases mortality and morbidity in cardiac surgery. Titanium plates have been used to reconstruct the chest wall for a long time. However, with the rise of 3D printing technology, a more sophisticated method, is making a breakthrough. Custom-made 3D-printed titanium prostheses are increasingly used in chest wall reconstruction because they allow almost perfect fitting to the patient's chest wall and lead to good functional and cosmetic results. This report presents a complex anterior chest wall reconstruction using a custom-made titanium 3D-printed implant in a patient with a sternal dehiscence after coronary artery bypass surgery. At first, reconstruction of the sternum was performed using conventional methods, which failed to give adequate results. Finally, a 3D-printed titanium custom-made prosthesis was used for the first time in our center. On the short- and mid-term follow up, good functional results were achieved. In conclusion, this method is suitable for sternal reconstruction after complications in the healing process of median sternotomy wounds in cardiac surgery, especially where other methods do not provide satisfactory results.

Surgeon-Guided Robotic Arm Facilitates LIMA Takedown in MIDCAB Surgery.

Left internal mammary artery (LIMA) to left anterior descending (LAD) coronary artery bypass has been scientifically proven to have the best patency and long-term results in myocardial revascularization. The latest guidelines suggest minimally invasive LIMA to LAD is the optimal therapy for isolated proximal LAD lesions. The start of a minimally invasive direct coronary artery bypass (MIDCAB) program can be quite challenging as robotic surgery demands high starting costs, while normal thoracoscopic techniques have a longer surgeon learning curve. In this article, we describe to the best of our knowledge the first use of surgeon-guided wristed instruments in LIMA harvesting for MIDCAB surgery. It allows for a facilitated LIMA harvest like in robotic surgery with the comfort of a surgeon constantly standing by the patient, allowing for a faster response time in case of an emergency or the need for instrument exchange. These features result in shorter operating times, lower costs compared with robotic surgery, and faster adoption of this technique for centers just starting MIDCAB surgery.

Altered Heart Rate Turbulence and Variability Parameters Predict 1-Year Mortality in Heart Failure with Preserved Ejection Fraction.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous clinical syndrome. In the absence of effective and potent treatment strategies, the main challenge in HFpEF management remains the availability of strong predictors of unfavourable outcomes. In our study, we sought to evaluate the potential prognostic value of heart rate turbulence (HRT) and variability (HRV) parameters on mortality in ambulatory HFpEF patients. METHODS: This was a case-control study comparing HRT and HRV parameters in HFpEF survivors vs. non-survivors. Patients from the RESPOND Heart Failure Registry with HFpEF who underwent 24 h ECG monitoring (Holter) were included; HRT parameters (i.e., turbulence onset (TO) and turbulence slope (TS)) and HRV parameters (i.e., standard deviation of NN intervals (SDNN)) derived from 24 h Holter ECGs were calculated in patients who died within 12 months, and compared to their age-, gender-, LVEF-, ECHO-, aetiology-, and therapy-matched alive controls. RESULTS: A total of 22 patients (mean age 80 ± 7 years, 18% female, mean LVEF 57 ± 9%) were included in the final analysis. In deceased patients, values of TO were significantly higher, and values of TS and SDNN were significantly lower as compared to survivors. CONCLUSIONS: HRT and HRV parameters have the ability to differentiate individuals with HFpEF who are at the greatest risk of unfavourable outcomes. The extent of autonomic disbalance as determined by HRT and HRV could potentially assist in the prognostic assessment and risk stratification of HFpEF patients.

Effect of Ascorbic Acid on Cardiac Surgery-Associated Acute Kidney Injury Incidence.

OBJECTIVES: Acute kidney injury (AKI) is associated with higher perioperative mortality and morbidity. Oxidative stress has been proposed as a cause of postoperative AKI. Ascorbic acid (AA) supplementation was suggested as a novel and promising antioxidant. The aim of this study was to evaluate the capability of AA to reduce the incidence of postoperative AKI in cardiac surgery patients. METHODS: A prospective randomized trial was conducted in patients scheduled for on-pump cardiac surgery. Subjects in the AA group received 2 g of AA intravenously during the induction of anesthesia, 2 g before aortic cross-clamp removal and 1 g every 8 hours for five postoperative days (the JERICA protocol). Postoperatively, the patients were monitored for AKI and other complications. Malondialdehyde levels were monitored in a subpopulation of 100 patients to evaluate the effect of AA on oxidative stress level. RESULTS: The AA and control group consisted of 163 and 169 patients, respectively. The groups were well matched for baseline demographics and had similar intraoperative characteristics. The incidence of AKI in the AA and control group was 20.9 and 28.4%, respectively (p = 0.127). The estimated glomerular filtration rate did not differ between the study groups in the entire postoperative period. There was a trend toward higher malondialdehyde values with statistical significance on postoperative day 1 and lower in-hospital mortality in the AA group (0.6 vs. 4.1%, p = 0.067). CONCLUSION: Our results do not support the effectiveness of AA supplementation in reducing the incidence of postoperative AKI in on-pump cardiac surgery patients. CLINICAL REGISTRATION NUMBER: This study was registered with the ISRCTN Registry under the trial registration number ISRCTN98572043.

THERMOACTIVE NITINOL CLIPS AS PRIMARY AND SECONDARY STERNAL CLOSURE AFTER CARDIAC SURGERY - FIRST EXPERIENCE IN SLOVENIA.

Although there has been a trend towards minimally invasive and sternum-sparing procedures, median sternotomy is still a standard surgical approach in cardiac surgery. Many techniques and innovations for closure of sternal osteotomy have been developed with contradictory results. In this report, we present our first experience with the nitinol-made sternal closure system in the primary, as well as secondary closure of sternal osteotomy. A small series of 20 patients had their sternotomy closed with Flexigrip clips. In one case, the Flexigrip clips were used in secondary wound closure in a patient with deep sternal wound infection after full sternotomy and coronary bypass surgery. After 6-month follow-up, all patients were doing well with their sternums clinically stable and the sternotomy wounds completely healed. In conclusion, Flexigrip clips offered a stable alternative to steel wires in primary, as well as secondary sternal closure. Moreover, in secondary sternal closure, the thermoactive clips offered safety advantages over the standard wire cerclage technique because the need for dissection of the substernal adhesions could be avoided.

ACUTE KIDNEY INJURY AFTER OPEN-HEART SURGERY PROCEDURES.

Cardiac surgery-associated acute kidney injury (CS-AKI) is a major complication associated with increased morbidity and mortality. There are multiple diagnostic criteria for CS-AKI. Despite many new investigations available for improved AKI diagnostics, creatinine and urea remain the cornerstone of diagnostics in everyday clinical practice. There are three major pathophysiological mechanisms that contribute to kidney injury, i.e. renal hypoperfusion, inflammation with oxidative stress, and use of nephrotoxic agents. Some risk factors have been identified that can be modified during the course of treatment (use of nephrotoxic agents, duration of cardiopulmonary bypass, type of extracorporeal circulation, postoperative low cardiac output or hypotension). The aim of AKI prevention should always be to prevent aggravation of renal failure and, if possible, to avoid progression to renal replacement therapy, which in turn brings worse long-term outcomes.

Pharmacodynamics of malondialdehyde as indirect oxidative stress marker after arrested-heart cardiopulmonary bypass surgery.

BACKGROUND: An unavoidable consequence of cardiac surgery is oxidative stress and resulting peroxidation of biological molecules, in particular unsaturated lipids. The detection of peroxidation metabolites in biological environments is difficult due to their large variety, small concentration, and high reactivity. One of the most studied lipid peroxidation products is malondialdehyde and as such an important marker of oxidative stress. The aim of this study was to monitor the perioperative serum concentration of malondialdehyde as an oxidative stress marker in patients undergoing arrested-heart cardiopulmonary bypass surgery. METHODS: This observational study was performed on 40 patients scheduled for on-pump arrested-heart open-heart surgery. Blood samples for the analysis of serum malondialdehyde were obtained preoperatively and intraoperatively immediately after the aortic clamp was removed. Afterwards, samples were obtained 12, 24, 48 and 72 h postoperatively. A gas chromatography-mass spectrometry analytical method was used to detect serum concentrations of malondialdehyde. RESULTS: A significant increase in serum malondialdehyde concentration was detected at the time of aortic declamping. The malondialdehyde serum concentration continued to increase and peaked 12 h postoperatively. Afterwards it started to decline, but remained significantly higher compared to preoperative values both at 24 and 48 h postoperatively. CONCLUSION: In contrast to some previous studies, our results demonstrate that in this patient population, the malondialdehyde levels do not peak at the end of the surgery, but continue to rise a few hours after surgery. Our findings indicate that in this patient population, oxidative stress with consequent lipid peroxidation is maintained and is even attenuated in the early postoperative period. This study was registered with the ISRCTN Registry under the trial registration number ISRCTN98572043.

Mycoplasma hominis Ascending Aortic Graft Infection Successfully Treated With Graft Preservation Using Negative Pressure Wound Therapy With Instillation and Dwell Time.

INTRODUCTION: Thoracic aortic graft infection is a rare complication after cardiac surgery with no consensus having been reached on the most appropriate type of management. Although most commonly caused by gram-positive cocci, aortic graft infection by Mycoplasma hominis can occur. CASE REPORT: A 63-year-old male patient with an aneurysm of the ascending aorta was admitted to the authors' institution for surgical treatment. A replacement of the ascending aorta with a polyester vascular graft was performed using a valve-sparing aortic valve reimplantation technique. During postoperative course, the patient became septic with a spiking fever and elevated inflammatory markers. A computed tomography scan revealed signs of mediastinitis. M hominis was identified in blood cultures and intraoperative tissue samples. An antibiogram-based antibiotic solution (tigecycline in 5% glucose solution) was instilled twice daily into the thoracic cavity using negative pressure wound therapy with instillation and dwell time for 8 days. This type of management allowed the authors to avoid graft replacement, and good midterm outcomes were achieved. CONCLUSIONS: To the authors' best knowledge, this is the first described successful treatment of an aortic graft infection caused by M hominis without a surgical removal of the prosthetic material using antibiotic irrigation.

Left ventricular pseudoaneurysm following atrioventricular groove rupture after mitral valve replacement.

Left ventricular pseudoaneurysm is a partial cardiac rupture, contained by the surrounding pericardium that maintains communication with the left ventricular lumen. Whereas most cases of left ventricular pseudoaneurysms are related to myocardial infarction (loss of myocardial integrity), only a handful are associated with valve surgery. We present a female patient, who was admitted for elective mitral valve replacement. After the implantation of the mechanical valve, we encountered a rupture of the atrioventricular groove. After 3 months, a left ventricular pseudoaneurysm was found and the patient was reoperated. The valve was explanted and the inspection of the annulus and previously implanted pericardial patch revealed a loosened stitch on the inferior (ventricular) side. The defect was reinforced with additional stitches and the valve was reimplanted. In conclusion, we report an unusual case with two serious complications after mitral valve replacement - atrioventricular groove rupture and left ventricular pseudoaneurysm.

Thoracoscopic retrieval of an atrial appendage occlusion device after embolization into the left ventricular outflow tract and damaging the mitral valve requiring replacement.

Embolization of a percutaneous left atrial appendage occlusion device is a rare, but potentially life-threatening, complication. In this report, we present the case of an embolization of such a device into the left ventricular outflow tract causing extensive damage to the mitral subvalvular apparatus and requiring mitral valve replacement. We also describe the first thoracoscopic removal of such a device from the left ventricular outflow tract.

Effect of Ascorbic Acid on Postoperative Acute Kidney Injury in Coronary Artery Bypass Graft Patients: A Pilot Study.

BACKGROUND: Even minor postoperative reductions in renal function influence the outcome of cardiac surgery. The mechanisms of postoperative renal injury in cardiac surgery are multifactorial and include ischemia-reperfusion injury. The study investigates the effect of the antioxidant ascorbic acid on the postoperative acute kidney injury after elective CABG surgery. METHODS: A prospective randomized single-center trial was conducted in on-pump coronary artery bypass patients. The patients in the ascorbic acid group received 2 grams of ascorbic acid 24 hours and 2 hours preoperatively and 1 gram twice daily five days after the surgery.  Postoperatively, the subjects were monitored for renal dysfunction and other complications. RESULTS: 100 patients were included, with 50 patients in each study group. The groups were well matched for baseline demographics, preoperative medications, comorbidities, and had similar intraoperative characteristics. The incidence of postoperative acute kidney injury in the ascorbic acid group was 16% and 14% in the control group (P = .779). The groups also did not differ in peak postoperative serum creatinine (83 [33] µmol/L versus 83 [39] µmol/L; P = .434), the lowest postoperative creatinine clearance (96.40 ± 35.78 mL/min versus 90.89 ± 36.18 mL/min; P = .766), and time from surgery to the onset of peak postoperative serum creatinine (1.64 ± 1.34 days versus 1.92 ± 1.54 days; P = .393). There was no dialysis required in any patient. Conclusion: The results of this study did not demonstrate a significant protective effect of ascorbic acid on the incidence of postoperative acute renal injury in elective on-pump CABG patients.

Perioperative ascorbic acid supplementation does not reduce the incidence of postoperative atrial fibrillation in on-pump coronary artery bypass graft patients.

BACKGROUND: Atrial fibrillation is the most common arrhythmia following cardiac surgery. It is associated with increased hemodynamic instability, systemic embolization, and complications linked to anticoagulant therapy. Oxidative stress and consequent electrophysiological remodeling have been proposed as a cause of postoperative atrial fibrillation. Ascorbic acid supplementation was suggested as a novel and effective preventive agent. The aim of this study was to evaluate the capability of ascorbic acid to reduce the incidence of postoperative atrial fibrillation in coronary artery bypass grafting (CABG) patients. METHODS: A prospective randomized single-center trial was conducted in patients scheduled for an elective on-pump CABG surgery. Subjects in the ascorbic acid group received 2g of ascorbic acid 24h and 2h before the surgery and 1g twice a day for five days after the surgery. Postoperatively, the patients were monitored for atrial fibrillation and other complications. RESULTS: The ascorbic acid group consisted of 52 patients and the control group included 53 patients. The groups were well matched for baseline demographics, preoperative medications, comorbidities, and had similar intraoperative characteristics. The incidence of atrial fibrillation in the ascorbic acid group was 13.5% and 18.9% in the control group (p=0.314). No difference was found between groups in the time of occurrence of atrial fibrillation (3.71±1.89 vs. 2.91±1.58 days after the surgery; p=0.342). There was also no difference in the other observed postoperative complications. CONCLUSIONS: The results of this study do not support the effectiveness of ascorbic acid supplementation in reducing the incidence of postoperative atrial fibrillation in elective on-pump CABG patients.

Effect of the Size of the Left Atrium on Sustained Sinus Rhythm in Patients Undergoing Mitral Valve Surgery and Concomitant Bipolar Radiofrequency Ablation for Atrial Fibrillation.

Atrial fibrillation is associated with systemic embolization and complications due to anticoagulant therapy. Radiofrequency ablation has been established as an effective and safe method for the treatment of atrial fibrillation. The aim of this study was to evaluate the effect of the size of the left atrium on the outcome of surgical radiofrequency ablation. Forty patients scheduled for elective mitral valve surgery and radiofrequency ablation were enrolled in the study. Group 1 consisted of patients with a left atrium diameter ≤5 cm and group 2 of patients with left atrium diameter >5 cm. The primary endpoint of the study was stable sinus rhythm 6 months postoperatively. At 6 months postoperatively, sinus rhythm was present in significantly more group 1 patients as compared with group 2 patients, i.e. 15 (75%) vs. 8 (40%), p=0.025. Multivariate analysis proved the size of the left atrium to be an independent predictor of the radiofrequency ablation outcome. Accordingly, the size of the left atrium was demonstrated to be an important predictor of the outcome of radiofrequency ablation for atrial fibrillation. A lower cut-off value of surgical reduction of the atria than previously reported should be considered in order to improve the radiofrequency ablation outcome.

Thrombocytopenia following implantation of the stentless biological sorin freedom SOLO valve.

BACKGROUND AND AIM OF THE STUDY: Stentless biological valves have proven advantages in hemodynamic performance and left ventricular function compared to stented biological valves. Following a marked postoperative fall in the platelet count of patients after implantation of the Freedom SOLO valve, the study aim was to confirm clinical observations that this effect was more severe in patients receiving Freedom SOLO valves than in those receiving St. Jude Medical (SJM) mechanical aortic valves. METHODS: Preoperative and postoperative platelet counts were compared in two groups of patients who underwent aortic valve replacement (AVR) without any concomitant procedures between January and December 2007. Patients received either a Freedom SOLO valve (n = 28) or a SJM mechanical valve (n = 41). Mean values of platelet counts were compared using three multiple linear regression models. RESULTS: Platelet counts were significantly lower in the Freedom SOLO group than in the SJM group from the first postoperative day (POD 1) up to POD 6 (p <0.001). In three patients of the Freedom SOLO group the platelet count fell below 30x10(9)/l, while the lowest level in the SJM group was 75x10(9)/l. Based on multiple linear regression models, the type of valve implanted had a statistically significant influence on postoperative platelet counts on POD 1, POD 3, and POD 5 (p <0.001). CONCLUSION: Whilst the reason for this phenomenon is unknown, the use of consistent monitoring should prevent severe falls in platelet count from becoming dangerous for the patient. Further studies are required to investigate the phenomenon since, despite a shorter cardiopulmonary bypass time, the fall in platelet count was more profound in the Freedom SOLO group.

Renal function after port access and median sternotomy mitral valve surgery.

BACKGROUND: Acute renal injury is an important postoperative complication of mitral valve surgery. We tested the hypothesis that minimally invasive port access (PA) surgery is linked to a smaller postoperative renal injury compared to the standard median Sternotomy (MS) technique. METHODS: Ninety-six patients in the PA group and 102 patients in the MS group were compared regarding postoperative renal dysfunction. Preoperative and maximal postoperative serum creatinine levels were used to calculate creatinine clearance which was implemented for the renal function assessment. Additionally, the new RIFLE classification for acute renal injury was used for the comparison of the postoperative kidney function. This classification is divided into 3 levels and in addition to the glomerular filtration rate, it is also based on urine output. RESULTS: The analysis of preoperative renal function did not demonstrate any significant differences between the two groups in any of the creatinine-based renal function markers. However, the comparison of the minimal postoperative creatinine clearance showed significantly lower values in the median sternotomy group. The conventional MS approach was confirmed as an independent renal risk factor in the multivariate analysis. The postoperative RIFLE classification comparison also showed higher postoperative renal impairment in the MS group. CONCLUSION: With the limitations of a retrospective study, our results suggest that for mitral valve surgery the minimally invasive PA approach might be associated with lower postoperative renal injury compared to the conventional surgical technique.