Two decades of recipient and donor referrals for heart transplantation to Groote Schuur Hospital, Cape Town, South Africa: A retrospective study.

BACKGROUND: Heart transplantation in South Africa faces numerous challenges related to organ scarcity and unequal access to advanced heart therapy. There is an urgent need to analyse the current transplant referral pathway to optimise equitable access to transplantation. OBJECTIVES: To provide an audit of heart transplant referrals to Groote Schuur Hospital, Cape Town, over a 23-year period, focusing on patient demographics, indications for referral, waiting-list dynamics, and transplant referral outcomes. METHODS: The study utilised a retrospective patient folder review for the period 1 January 1997 - 31 December 2019 and audited the trends in heart transplant referrals and associated outcomes of the referral at a tertiary academic hospital. RESULTS: A total of 625 recipients were referred for heart transplantation, with the majority being male (n=412; 65.9%), while gender was undocumented for 69 cases (11.0%). The mean age was 38.1 (14.6) years, and 153 (24.5%) were listed for transplant, while 215 (34.4%) were deemed ineligible for listing. Contraindications for listing included social (n=106; 49.3%), medical (n=83; 38.6%) and psychological (n=26; 12.0%) factors, while 134 patients (21.4%) were considered too well. Poor social circumstances (n=38; 39.6%), poor insight (n=28; 29.2%) and poor compliance (n=21; 21.9%) were the most common non-medical reasons for not listing recipients, while obesity (n=30; 31.3%) and smoking (n=23; 24.0%) were notable medical contraindications. Forty-nine patients (7.8%) died during work-up, while 130 (85.0%) of the listed patients received a heart transplant. Of the 429 donor referrals, 139 (32.4%) were accepted for organ procurement. Reasons for declining donors included unsuitability for transplantation (30.3%), lack of capacity (1.8%), and recipient-donor mismatch (66.9%). CONCLUSION: Three-quarters of the referred patients were deemed unsuitable for heart transplantation for medical and/or social reasons. The ratio of referral to listing has decreased over time. However, once listed, the likelihood of receiving a transplant was high.

2022 SASCI/SCTSSA joint consensus statement and guideline on transcatheter aortic valve implantation (TAVI) in South Africa.

Patients with severe symptomatic aortic stenosis (AS) have traditionally been treated with surgical aortic valve replacement (sAVR). Transcatheter aortic valve implantation is a percutaneous option that has been shown to be at least as effective as sAVR in numerous subgroups of patients with severe AS. This is an update on the previous joint consensus statement and guideline on transcatheter aortic valve implantation (TAVI) in South Africa, published in 2016. It provides guidance on which patients should preferably be offered TAVI over sAVR, with special consideration of the resource-constrained environment in South Africa.

Dosimetric and Clinical Predictors for Acute and Late Gastrointestinal Toxicity Following Chemoradiotherapy of Locally Advanced Anal Cancer.

AIMS: To analyse dosimetric and clinical predictors for acute and late gastrointestinal toxicity following chemoradiotherapy of anal cancer. MATERIALS AND METHODS: Consecutive patients with locally advanced (T2 ≥4 cm - T4 or N+) anal cancer were selected from an institutional database (n = 114). All received intensity-modulated radiotherapy with concomitant 5-fluorouracil and mitomycin C. Gastrointestinal toxicity was retrospectively graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and bowel cavity, small bowel and large bowel were contoured. Dosimetric and clinical variables were tested for associations with acute grade ≥3 gastrointestinal toxicity and late grade ≥2 gastrointestinal toxicity using the Mann-Whitney test, area under receiver operating characteristic curve (AUC) and logistic regression. RESULTS: The median follow-up was 40 months. Acute grade ≥3 gastrointestinal toxicity was seen in 51 (44.7%) of the patients; late grade ≥2 gastrointestinal toxicity was seen in 36 of the patients (39.6% of 91 patients with >1 year recurrence-free follow-up). Bowel cavity V30Gy was the best dosimetric predictor for acute gastrointestinal toxicity (AUC 0.633; P = 0.02). Large bowel V20Gy was the best dosimetric predictor for late gastrointestinal toxicity (AUC 0.698; P = 0.001) but showed no association with acute gastrointestinal toxicity. In multivariate logistic regression, increasing age was significantly associated with acute gastrointestinal toxicity; smoking and large bowel V20Gy were significantly associated with late gastrointestinal toxicity. Patients who experienced acute grade ≥3 gastrointestinal toxicity were not at an increased risk of late grade ≥2 gastrointestinal toxicity (odds ratio 1.3; P = 0.55). CONCLUSIONS: Factors of importance for acute and late gastrointestinal toxicity were not the same. Bowel cavity V30Gy is a good metric to use for the prediction of acute gastrointestinal toxicity, but the results of our study indicate that individual large and small bowel loops need to be contoured for better prediction of late gastrointestinal toxicity. The role of the large bowel as an important organ at risk for late gastrointestinal toxicity merits further research.

Breathing-motion induced interplay effects for stereotactic body radiotherapy of liver tumours using flattening-filter free volumetric modulated arc therapy.

The purpose of this study was to investigate breathing-motion induced interplay effects for stereotactic body radiotherapy (SBRT) of liver tumours treated with flattening-filter free (FFF) volumetric modulated arc therapy (VMAT). Ten patients previously treated with liver SBRT were included in this study. All patients had four-dimensional computed tomography (4DCT) scans acquired prior to treatment. The 4DCT was sorted into 8-10 phases covering an equal time interval. A FFF VMAT plan was created for one fraction in the mid-ventilation phase for each patient. To generate dose distributions including both interplay effects and dose blurring, a sub-plan was calculated for each phase. The total dose distributions were accumulated to the mid-ventilation phase using the deformed vector fields (DVF) from deformable image registration between the corresponding CT and the mid-ventilation phase CT. A blurred dose distribution, not including interplay effects, was also obtained by distributing the delivery of the whole plan uniformly on all phases, and was similarly accumulated to the mid-ventilation phase. To isolate interplay effects, this blurred dose distribution was subtracted from the total dose distribution with interplay effects. The near minimum dose (D 98%), mean dose (D mean), heterogeneity index (HI), and the near minimum dose difference (ΔD 98%) between the accumulated dose distributions with and without interplay effects were calculated within the gross tumour volume (GTV) for each patient. Comparing the accumulated dose distributions with and without interplay effects, the D 98% decreased for nine of the ten patients and the HI increased for all patients. The median and minimum differences in D 98% were -2.1% and -5.0% (p = 0.006), respectively, and the median HI significantly increased from 6.2% to 12.2% (p = 0.002). The median ΔD 98% was -4.0% (range -7% to -1.5%). In conclusion, statistically significant breathing-induced interplay effects were observed for a single fraction of FFF VMAT liver SBRT, resulting in heterogeneous dose distributions within the GTV.

Mechanical loadings on pectoral pacemaker implants: correlation of in-line and transverse force of the Pectoralis major.

Recently we presented a method for the assessment of in vivo forces on pectoral device implants motivated from technological and clinical advancements toward smaller implantable cardiac pacemakers and the altered structural demands arising from the reduced device size. Objective of this study was the investigation of the intra-species proportionality of in-line force and transverse reaction force of the Pectoralis major for the characterization of mechanical in vivo loadings on pectoral implants. Two Chacma baboons (23.9 ± 1.2 kg) received bilaterally one chronic and one acute pectoral sub-muscular instrumented pacemaker (IPM) implant. The Pectoralis major muscle was electrically stimulated and resulting in-line and transverse muscle force were measured. The correlation of in-line force and transverse force of the Pectoralis major was investigated using linear regression analyses. The proportionality of in-line and transverse force of the Pectoralis major was found to be subject-specific (R² = 0.17, p < 0.003). Including morphometric parameters, i.e., length along line of action, width over implant and stress, in the regression analysis provided a strong intra-species correlation between in-line and transverse force (R² = 0.71, p < 10⁻7). The novel intra-species correlation provides a tool toward the characterization of mechanical in vivo loading conditions of pectoral device implants.