Effects of Preoperative Angiotensin-Converting Enzyme Inhibitor Therapy on Postoperative Renal Function in Cardiac Surgery.

A Best Evidence Topic in cardiac surgery was written according to a structured protocol. The question addressed was-"In patients who undergo cardiac surgery, is preoperative angiotensin-converting enzyme inhibitor therapy associated with postoperative renal dysfunction?" Altogether, 339 papers were found using the reported search. Ten (10) were chosen which best answered the clinical question. The papers were evaluated for bias and heterogeneity using validated tools and the collected results analysed qualitatively. Evidence in the current literature is inconclusive that preoperative administration of angiotensin-converting enzyme inhibitor therapy affects postoperative renal dysfunction in patients undergoing cardiac surgery.

Vein Graft Patency Rates With Aspirin Plus Clopidogrel Following Coronary Artery Bypass Grafting.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, "In patients who have undergone Coronary Artery Bypass Grafting, does aspirin plus clopidogrel postoperatively improve vein graft patency when compared to aspirin alone?" Altogether, 165 papers were found using the reported search, of which five represented the best evidence to answer the clinical question. Overall analysis of these papers demonstrated similar rates of vein graft patency between the two groups. There was no difference between the groups with regard to mortality, adverse bleeding-related outcomes, or composite vascular events.

Drug-eluting versus bare-metal stents for saphenous vein graft lesions.

A best evidence topic was written addressing the question 'in patients with saphenous vein graft lesions requiring percutaneous coronary intervention, do long-term clinical outcomes differ between drug-eluting and bare-metal stents?' Altogether 1466 papers were found, of which seven represented the best evidence. Although one major recent randomised trial was neutral, the weight of earlier evidence supports drug-eluting stents as standard of care. Bare-metal stents may represent a reasonable, efficacious, and less expensive alternative to drug-eluting stents in well selected patient groups.

Do patients with the centrifugal flow HeartMate 3 or HeartWare left ventricular assist device have better outcomes compared to those with axial flow HeartMate II?

A best evidence topic was written according to a structured protocol. The question addressed was 'Do patients with centrifugal flow HeartMate 3 (HM3) or HeartWare left ventricular assist device (HVAD) have better outcomes compared to those with the axial flow HeartMate II (HMII)?' Altogether 1791 papers were found using the reported search, of which 21 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. In publications reporting on MOMENTUM 3 randomized control trial (RCT), HM3 had better outcomes compared to HMII with a lower rate of pump thrombosis (1.1% vs 15.7%), stroke events (10.1% vs 19.2%) and ischaemic stroke (6.3% vs 13.4%) at 2-year follow-up. Markers of quality of life and functional capacity were comparable between the 2 devices at 6 months. In publications reporting on ENDURANCE RCTs, compared to HMII, patients with HVAD had poorer outcomes with an increased rate of sepsis (23.6% vs 15.4%), stroke (29.7% vs 12.1%) and right heart failure (38.5% vs 26.8%) postoperatively. Outcomes were improved for the HVAD group in a more recent RCT where strict blood pressure control was instigated postoperatively. Outcomes from retrospective studies comparing HMII with HVAD varied, with some publications reporting higher rates of right ventricular assist device use (29% vs 15%), gastrointestinal bleeding (30% vs 0%), cerebrovascular accident (44% vs 10%), transient ischaemic attack (5% vs 2%) and higher cumulative risk of infection and haemorrhagic cerebrovascular accident with HVAD. This is not consistent across these studies, and 9 studies including a systematic review reported no difference in any outcomes. In conclusion, patients with centrifugal flow HM3 have better outcomes than those with axial flow HMII. Although there is some variability in outcomes in retrospective studies, patients with centrifugal flow HeartWare HVAD have similar outcomes to those with axial flow HMII when strict blood pressure control is instigated postoperatively. By inference, centrifugal flow HM3 would appear to be the superior device, although all conclusions are based on 1 large (industry-sponsored) RCT.

Management of atrial fibrillation after cardiac surgery.

A best evidence topic in cardiac surgery was written according to a structured protocol addressing the question 'for post-cardiac surgery atrial fibrillation (AF), do clinical outcomes differ between rate or rhythm control strategies?' Altogether, 2174 papers were found using the reported searches, of which 5 represented the best evidence to answer the clinical question. Hospital length of stay ranged from 5.0 to 13.2 days for rate control and 5.2 to 10.3 days for rhythm control. Freedom from AF at follow up was achieved in 84.2-91 and 84.2-96% in rate and rhythm control groups respectively. Minimal serious adverse events were noted in all studies analysed and there was no difference between rate and rhythm control groups. We conclude that in the management of post-cardiac surgery, AF, rate control and rhythm control are equivalent in terms of hospital length of stay, freedom from arrhythmia at follow up and complication rates.

Spontaneous echo contrast mimicking aortic root thrombus in a patient supported with extracorporeal membrane oxygenation.

Aortic root spontaneous echo contrast is a rare but significant finding. We report a 31-year-old female who was placed on venoarterial extracorporeal membrane oxygenation emergently for acute mitral regurgitation secondary to papillary muscle rupture. Following stabilization, subsequent transesophageal echocardiography suggested aortic root thrombus and prompted emergent surgery. However, further inspection with intraoperative transesophageal echocardiography revealed a spontaneous echo contrast which aided us in the intraoperative decision making.

Levosimendan Following Cardiac Surgery.

A best evidence topic was written to address if perioperative levosimendan improves mortality following cardiac surgery. Fourteen papers represented the best available evidence. An older meta-analysis summarising 11 of these trials concluded that there were fewer deaths in the levosimendan group compared to the control group (OR 0.41, p <0.001) however, this was driven by the results of three included trials by the same author. Three larger and more recent randomised controlled trials failed to demonstrate significant differences in mortality. We conclude that levosimendan lacks robust evidence to substantiate claims of mortality benefit in cardiac surgery patients and should not be used routinely in such patients.