SIGNIFICANCE: In early 2022, we analysed the benefits of switching the fuel for the Ankerlig peaking plant from diesel to LPG (liquified petroleum gas or 'bottled' gas) to reduce cost, improve greenhouse gas emissions and provide for the long-term needs of the South African electricity grid. That analysis was published in May 2022 (Clark et al. J Energy South Afr. 2022;33(2):15-23). With increased load shedding and the higher cost of diesel fuel, this recommended fuel change has become even more relevant. In this commentary, we summarise the conclusions from that paper and related studies and update the results to reflect the latest situation within the country.

Abstract Introduction: Carcinoid heart disease most frequently involves the tricuspid or, more rarely, the pulmonary valve and presents with right heart failure as 5-HT is metabolized by the lung. Left-sided valve involvement is quite rare. We describe our experience of 3 patients presenting with heart failure secondary to carcinoid heart disease affecting all four cardiac valves. There are only four previous isolated case reports in the literature. Methods: All three patients underwent quadruple valve replacement during a single operation. Right ventricular outflow tract reconstruction with a pericardial patch was performed in all patients. For 24 hours prior to surgery, all patients received intravenous octreotide, which continued in intensive care for at least 24 hours. Results: Mean cross-clamp and bypass times were 175 (range 164-197 minutes) and 210 (range 195-229 minutes) minutes, respectively. Mean intensive treatment unit (ITU) and inpatient stays were 2.3 (range 2-3 days) and 12 (range 9-16 days) days, respectively. One patient was reopened for bleeding 4 hours postoperatively from a ventricular pacing wire site. None required a permanent pacemaker postoperatively. There were no other complications in any patient. The quality of life was excellent at 6-16 months clinic follow-up as they were in NYHA 1. Postoperative echocardiography showed no paravalvular leaks and well-functioning prostheses in all cases. Conclusion: Surgery to replace all four valves is feasible with excellent medium-term survival and a very low rate of complications. Patients with carcinoid heart disease should always be considered for surgery irrespective of the extent of valvular involvement.

Abstract Objective: The aim of this retrospective study was to compare early postoperative outcomes after aortic valve replacement (AVR) with sutureless bioprostheses and conventional stented bioprostheses implanted through median sternotomy. Methods: From January 2011 to December 2016, 763 patients underwent aortic valve replacement with bioprostheses; of these, 139 received a Perceval S sutureless valve (Group A) and 624 received a Perimount Magna Ease valve (Group B). These groups were further divided into A1 (isolated Perceval AVR), A2 (Perceval AVR with coronary artery bypass grafting [CABG]), B1 (isolated conventional stented bioprosthesis), and B2 (conventional stented bioprosthesis + CABG). Results: Patients in Group A were older (mean 74 years vs. 71 years; P<0.0001), predominantly women (53% vs. 32%; P<0.0001), had a higher logistic EuroSCORE (3.26 vs. 2.43; P<0.001), more preoperative atrial fibrillation (20% vs. 13%; P=0.03), and had a lower reopening rate for bleeding (2.1% vs. 6.7%; P=0.04). Compared to Group B1, Group A1 had shorter cross-clamp (mean 40 min vs. 57 min; P≤0.0001) and bypass times (mean 63 min vs. mean 80 min; P=0.02), and they bled less postoperatively (mean 295 ml vs. mean 393 ml; P=0.002). The mean gradient across Perceval valve was 12.5 mmHg while its effective orifice area was 1.5 cm2. Conclusion: In our retrospective study of 763 patients, sutureless valve group patients are older, mostly women, more symptomatic preoperatively, and have higher logistic EuroSCORE. They have shorter cross-clamp and bypass times, less postoperative bleeding, and reduced incidence of reopening. Further studies are needed to evaluate the clinical benefits in short, mid, and long-terms.

Abstract Introduction: The incidence of postoperative thrombocytopenia after aortic valve replacement (AVR) with the Perceval S Sutureless bioprosthesis remains unclear. The aim of this study was to report thrombocytopenia associated with the use of sutureless AVR. Methods: The data was collected retrospectively for patients who had isolated AVR with sutureless Perceval S valve (Group A: 72 patients) and was compared with patients who underwent isolated sutured AVR with Perimount Magna Ease Bioprosthesis (Group B: 101 patients) in our institution between June 2014 and January 2017. Results: Cardiopulmonary bypass and cross-clamp time were significantly shorter in group A. Maximum drop in platelet count was 58% mean (day 2.3) in group A versus 44% mean (day 1.7) in group B (P=0.0001). Absolute platelet count on postoperative day 1-6 in group A was significantly less than in group B (P≤0.05). Platelet count recovered to preoperative value in 44% patients in group B versus only in 26% patients in group A at discharge (P=0.018). Moderate thrombocytopenia occurs more often in group A (41% vs. 26%) (P=0.008) while severe thrombocytopenia (<50 x 109) was observed in 6% in group A but never in group B. Platelets (P=0.007) and packed red blood cells (P=0.009) transfusion was significantly higher in the group A. Conclusion: The implantation of sutureless Perceval aortic valves was associated with a significant drop in platelet count postoperatively with slow recovery and higher platelets and packed red blood cells transfusion requirements. A prospective randomised trial is needed to confirm our findings.

Abstract Objective: The aim of this retrospective study is to evaluate the safety and performance of the Perceval sutureless valve in patients undergoing aortic valve replacement. We report the 30-day clinical outcomes of 139 patients. Methods: From January 2014 to December 2016, 139 patients underwent sutureless aortic valve replacement. Their operation notes, National Adult Cardiac Surgery Database and perioperative transoesophageal echocardiography findings were studied retrospectively. Results: Ninety-two patients underwent isolated aortic valve replacement (group A) with Perceval valve and 47 patients had combined procedures of aortic valve replacement and coronary artery bypass grafting (group B). The patients received a size S (n=23), M (n=39), L (n=42) or XL (n=35) prosthesis. Perceval valve was successfully implanted in 135 (97.1%) patients. Mean cross-clamping time and bypass time were 40 and 63 minutes for isolated cases, while 68 and 107 minutes for combined cases. Three (2.1%) patients died within 30 days. Four patients suffered stroke and 5 patients went into acute renal failure. Median intensive care unit and hospital stay was 2 and 8.5, respectively. Four valves were explanted due to significant paravalvular leak after surgery. Five patients had permanent pacemaker as a result of complete heart block and mean postoperative drainage was 295 mL for isolated case and 457 mL for combined cases. The mean gradient across Perceval valve was 12.5 mmHg while its effective orifice area was 1.5 cm2. Conclusion: Early postoperative results showed that Perceval valve is safe. Further follow up is needed to evaluate the long-term outcome with this bioprosthesis.