Correlation between carotid intima-media thickness and patient outcomes in coronary artery disease in central South Africa.

OBJECTIVES: Carotid intima-medial thickness (CIMT) is a non-invasive tool used to detect atherosclerosis and diagnose cardiovascular disease. This study aimed to determine whether pre-operative CIMT measurements correlated with intra- and postoperative outcomes in patients with acute coronary syndrome (ACS) undergoing coronary artery bypass graft (CABG) surgery. METHODS: This retrospective, analytical cohort included 89 patients diagnosed with ACS who received CABG surgery. Patients were divided into two cohorts: group 1: normal CIMT < 0.07 cm and group 2: abnormal CIMT ≥ 0.07 cm. B-mode ultrasound was used to measure the CIMT in all patients. Pre-, intra- and postoperative data and complications were recorded for each patient. RESULTS: The study included 77 (86.5%) males and 12 (13.5%) females. Pre-operative mean body mass index was significantly higher (p = 0.03) in group 2 than in group 1. Group 2 had a significantly increased incidence of diabetes (p = 0.008) and hypertension (p = 0.009), and increased NT-proBNP levels (p = 0.02). Intra- and postoperative outcomes between the groups were comparable, with no significant differences. CONCLUSION: The study showed no correlation between abnormal CIMT and increased adverse intra- and postoperative patient outcomes. Therefore, the results of this study show CIMT should not be considered a tool to predict adverse events in patients undergoing CABG surgery.

Outcomes of single-ventricle physiology in central South Africa.

INTRODUCTION: Single-ventricle physiology is a critical cardiac condition requiring early diagnosis and intervention. The objectives of this study were to report on the management and outcomes of patients diagnosed with single-ventricle physiology in central South Africa. METHODS: This study was a retrospective, observational analysis of patients presenting with single-ventricle physiology at the Universitas Academic Hospital in central South Africa between November 1997 and June 2021. RESULTS: Patients were referred from the Free State (54%) and Northern Cape (29%) provinces and Lesotho. One hundred and fifty-four patients presented with single-ventricle physiology: 114 received interventions and 40 were not eligible for intervention. Patients presented for the first time at a median age of 34.5 days, with patients from nearby districts presenting within a few days of birth. However, patients from outlying areas presented much later. Eighty-seven patients received systemic-to-pulmonary artery shunting or pulmonary artery banding. Sixty-three patients proceeded to bidirectional Glenn procedures, and 30 patients (26%) had full palliation to Fontan. Twenty-one patients died after stage 1, six after the Glenn procedure and two after the Fontan procedure. Overall, 34 (29.8%) patients were lost to follow up. CONCLUSION: Patients in our study presented late and follow up of these patients was a challenge. The highest mortality rate occurs during the first stage of palliation. Outcomes from this study are comparable to other sub-Saharan studies.

Advantages of decellularized bovine pericardial scaffolds compared to glutaraldehyde fixed bovine pericardial patches demonstrated in a 180-day implant ovine study.

Glutaraldehyde (GA)-fixed bovine pericardial patches remain the cardiovascular industry standard despite reports of degradation, thickening, inflammation, calcification and lack of tissue remodelling. Decellularization provides the opportunity to attenuate some of these immune-mediated processes. This study compared the mechanical and morphological integrity of bovine pericardium that is GA-fixated (Glycar® patches) or decellularized (BPS), using a proprietary protocol, following implantation in an ovine model. The impact of the processing methods on tissue strength and morphology was assessed prior to implantation. Pericardial patches were then implanted in the descending aorta and main pulmonary artery of juvenile sheep (n = 6 per group) for 180 days, and clinically evaluated using echocardiography. At explanation, patches were evaluated for strength, calcification and biological interaction. Histology demonstrated a wave-like appearance of well-separated collagen fibers for BPS scaffolds that provided pore sizes adequate to promote fibroblast infiltration. The collagen of the Glycar® patches showed loss of collagen fiber integrity, making the collagen densely compacted, contributing to insignificant recipient cell infiltration. The clinical performance of both groups was excellent, and echocardiography confirmed the absence of aneurysm formation, calcification and degeneration. Explanted Glycar® patches demonstrated cells in abundance within the fibrous encapsulation that separated the implant from the host tissue. More importantly, the fibrous encapsulation also contributed to patch thickening of both the explanted aorta and pulmonary patches. The decellularized pericardial scaffolds demonstrated recellularization, resistance to calcification, re-endothelialization and adequate strength after 180-day implantation. The proprietary decellularization protocol produced pericardial scaffolds that could be considered as an alternative to GA-fixed pericardial patches.

The sequential effects of a multifactorial detergent based decellularization process on bovine pericardium.

Decellularization is a promising method for obtaining extracellular matrix scaffolds (ECM) to be used as replacement material in reconstructive procedures. The effectiveness of decellularization and the alterations to the ECM vary, depending on several factors, including the tissue source, composition and density. With an optimized decellularization process, decellularized scaffolds can preserve the spatial and temporal ECM microenvironment, which play an integral role in modulating cell migration, proliferation and differentiation. The exploration of a variety of decellularization protocols has led to mixed outcomes and comparisons between decellularization protocols could not attribute these differences to any single step in a multiple-step process. This study aimed to characterize the effects of each step of a multifactorial decellularization method on the scaffold structure and mechanical integrity of bovine pericardium. Each step of the decellularization process and the effect on the tissue was assessed using hematoxylin and eosin staining, electron microscopy, total protein, ECM protein and triglyceride quantification. The biomechanical properties were assessed using uniaxial tensile strength testing. Cell lysis occurred mainly during the detergent and alcohol steps. Collagen structural damage occurred during the detergent and alcohol steps, with no significant decreased in collagen concentration. No significant damage to elastin could be shown throughout the process, however glycosaminoglycans were significantly removed by detergent treatment. Triglycerides were removed mostly by the alcohol treatment. The strength of the pericardium decreased somewhat after each step of the protocol. It is important to characterize each decellularization protocol with regards to the decellularization efficiency and the effect on the ECM proteins structure and function to accurately evaluatein vivooutcomes.

Outcome determinants of urethroplasty in the management of inflammatory anterior urethral strictures.

BACKGROUND: Limited data are available on outcomes of the surgical management of inflammatory urethral strictures secondary to infection, a major cause of stricture. Several shortcomings that need to be addressed have been identified in the past. OBJECTIVE: To determine the impact of stricture length, position and degree of obliterative urethral lumen on the surgical outcomes of corrective procedures for inflammatory anterior urethral strictures. METHODS: This retrospective analysis used the records of patients who presented with proven infective anterior urethral strictures at an academic hospital from 2007 to 2010. All patients were followed up after 48 months. Urethroplasty outcomes were analysed according to stricture location and length and effect of urethral obliteration. RESULTS: The median age of the 174 patients in the study was 47 (range 21 - 86) years. Anastomotic urethroplasty was successful in 59/99 (59.6%) patients. Augmented anastomotic urethroplasty was successful in 11/15 (73.3%) patients. Dorsal onlay buccal mucosa graft urethroplasty was successful in 23/32 (71.9%) patients, significantly higher than in 2/9 (22.2%) patients who underwent ventral onlay buccal mucosa graft urethroplasty (p=0.017; hazard ratio 3.4; 95% confidence interval 1.29 - 9.40). The one-stage circular pedicled penile skin-flap urethroplasty was successful in 1/12 (8.3%) patients. Two-stage urethroplasty was successful in 5/7 (71.4%) patients. A primary component analysis of the 73 failed procedures showed that stricture length was the main contributor to failure (eigenvalue 1.79; 45%). CONCLUSIONS: Urethroplasty remains a challenge in inflammatory urethral strictures, where stricture length was the main reason for treatment failure.

The effect of different treatment modalities on the calcification potential and cross-linking stability of bovine pericardium.

Porcine heart valves and bovine pericardium exhibit suitable properties for use as substitutes in cardiothoracic surgery, but must meet several requirements to be safe and efficient. Treatment with glutaraldehyde (GA) render some of these requirements, but calcification and degradation post-implant remain a problem. This study aimed to identify additional biochemical treatments that will minimize calcification potential without compromising the physical properties of pericardium. Pericardium treated with GA calcified severely after 8 weeks in the subcutaneous rat model, compared to tissue treated with higher concentrations of glycosaminoglycans (GAG) and commercial Glycar patches. GA, lower concentrations GAG and Glycar pericardium had high denaturation temperatures due to enhanced cross-linking. Tensile strength of GA tissue was significantly lower than GAG-treated or Glycar tissues, due to lower water content with resultant lower flexibility and suppleness. Pericardium treated with 0.01 M GAG gave acceptable denaturation temperatures, tensile strength and reduced calcification potential. All tissue treatments evoked comparable host immune responses, and no significant difference in resistance to enzymatic degradation. Ineffective stabilization and fixation of cross-links following GAG treatment, as well as limited penetration into the pericardium, resulted in GAG leaching out into the surrounding host tissue or storage medium, and prohibits safe clinical use of such tissue.