The timing of surgical revascularization in acute myocardial infarction: when should we intervene?

INTRODUCTION: Coronary artery bypass grafting (CABG) is a crucial intervention in acute myocardial infarction (AMI), particularly when AMI is not amenable for management with primary percutaneous coronary intervention (PCI). To optimize outcome in these patients, surgical teams must consider a host of predictive factors, with the most prominent being the timing of CABG. Despite numerous studies exploring timing of CABG following AMI in the past, optimal surgical timing remains controversial. The mortality rates vary with timing of CABG, but confounding factors such as age, impaired pulmonary function, renal insufficiency, and poor left ventricular function may contribute to varied outcomes reported. EVIDENCE ACQUISITON: An electronic literature search of articles that discussed acute myocardial presentation and urgent in-patient or elective CABG was conducted. EVIDENCE SYNTHESIS: The evidence was synthesized based on each reported article and their outcomes. CONCLUSIONS: Current literature suggests multiple factors can guide CABG timing including, type of AMI at initial presentation, distinctive pathological status, and patient characteristics. Thus, there is a need for large, multi-center studies to identify optimal CABG timing in complex coronary artery disease or failed PCI in patients with AMI. Future guidelines should emphasize patient cohorts by taking their risk factors into consideration. As such, a need for greater cardiac screening methods and development of scoring systems can aid in the optimization of CABG timing.

Skeletonized or Pedicled Harvesting of Left Internal Mammary Artery: A Systematic Review and Meta-analysis.

We sought to compare clinical outcomes in skeletonized versus pedicled left internal mammary artery (LIMA) grafts in elective coronary artery bypass grafting through a systematic review and meta-analysis. A comprehensive electronic literature search of PubMed, Ovid, Embase, and Scopus was conducted from inception to January 2020. Only short-term (30 days) studies which compared both techniques have been included in our analysis. Primary outcomes were post anastomosis flow rate and sternal wound infection rate (SWI); secondary outcomes were conduit length, acute myocardial infarction and 30-day mortality. Thirteen articles with a total of 6222 patients met the inclusion criteria. Except for the prevalence of diabetes mellitus being significantly lower in the skeletonized cohort (odds ratio [OR] 0.77 95% confidence interval [CI] [0.61, 0.97], P = 0.03), there were no differences in the preoperative demographics between the 2 groups. The skeletonized LIMA conduit was significantly longer when compared to the pedicled conduit (weighted mean difference -2.64 cm 95% CI [-3.71, -1.56], P < 0.0001). SWI rates were not significantly different in the skeletonized versus pedicled LIMA group (OR 0.71 95% CI [0.47, 1.06], P = 0.10). New onset of acute myocardial infarction and 30-day mortality rate was similar in the 2 groups (OR 1.04 and 0.97, respectively, P > 0.05 in both). The postanastomoses flow rate was higher in skeletonized LIMA (Weighted Mean Difference -11.51 mL/min 95% CI [-20.54, -2.49], P < 0.01). Harvesting the LIMA using the skeletonized technique is associated with higher postanastomosis flow rates and longer conduit lengths; with no difference in SWI and mortality rates when compared to the pedicled technique. We suggest that this technique should be adopted, particularly for BITA harvesting. However, further research is needed to provide clearer indications for both methods.

Harvesting internal mammary artery: a narrative review.

INTRODUCTION: Scientific literature has highlighted the development of surgical procedures with studies investigating optimal selection of arterial conduit, ideal harvesting method and type of graft. There have also been studies on the utility and efficiency of harvesting the internal mammary artery (IMA) through minimally invasive techniques such as endoscopic and robotic assisted methods. In the pursuit of a more total and complete revascularization of the coronary arteries, surgeons have also explored more extensive anastomosis techniques, i.e. sequential and no-touch. This review analyzes the literature in order to better understand the various methods for harvesting and using the IMA in coronary artery bypass graft (CABG) through outlining the pros and cons of each methodology. EVIDENCE ACQUISITION: Literature search on PubMed and Google Scholar was performed using search terms such as "CABG," "IMA," "internal thoracic artery," "harvesting," "technique," and "approach." Manuscripts in languages other than English were not considered. Manuscripts that assess outcomes of IMA harvesting are reviewed and included. EVIDENCE SYNTHESIS: A review of 48 studies, narrowed down from 150 articles that were retrieved, were used to evaluate current evidence for different IMA harvesting techniques. This includes evidence comparing various techniques: skeletonized and pedicled harvesting, minimally invasive techniques for harvesting; free arterial and in-situ grafts; no-aortic touch technique sequential grafting. CONCLUSIONS: Each technique and harvesting method is associate with various advantages and disadvantages. Common patterns in patient outcomes were identified for many of the techniques. This review provides a summary and overview of the current evidence base for CAGB surgery and identifies gaps in the evidence base to direct future research.