Faculty Bibliography

Patients with diabetes mellitus (DM) have more severe CAD and higher mortality in acute coronary syndrome (ACS) than patients without DM. The optimal mode of revascularization-coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI)-remains controversial in this setting. For patients with DM and ST-segment elevation myocardial infarction, prompt revascularization of the culprit artery via PCI is generally preferable. In non-ST-elevation ACS, the decision on mode of revascularization is more challenging. Trials comparing CABG with percutaneous transluminal coronary angioplasty, bare metal stents, and first-generation drug-eluting stents in DM patients with multivessel have demonstrated decreased mortality in those receiving CABG. On the other hand, trials and retrospective analyses comparing CABG to PCI with second-generation drug-eluting stents have not shown a statistically significant mortality benefit favoring CABG. This potentially narrowed that gap between CABG and PCI requires further investigation.

The SCAI Publications Committee and Emerging Leadership Mentorship (ELM) Fellows concisely summarize and provide context on the most important coronary trials presented at large international meetings in 2015, including the MATRIX, ABSORB, and TOTAL trials. The intent is to allow quick assimilation of trial results into interventional practice, and enable busy interventional cardiologists to stay up to date. (c) 2016 Wiley Periodicals, Inc.

Background: Unlike for coronary artery disease, the association between neutrophil-lymphocyte ratio (NLR) and peripheral artery disease (PAD) has not been well established. The aim of this study was to determine the association between neutrophil-lymphocyte ratio and the severity of lower extremity peripheral artery disease. Methods: A retrospective chart review analysis identified 928 patients referred for peripheral angiography at a tertiary care center between December 2012 and June 2015. NLR was assessed from routine pre-procedural hemograms with automated differentials and available in 733 (79%) patients. Outcomes of interest included extent of disease on peripheral angiography and target vessel revascularization. Median follow-up was 10.4 months. Odds ratio (OR) [95% confidence intervals] was assessed using a logistic regression model. Results: There was a significant association between elevated NLR and the presence of severe multi-level PAD versus isolated suprapopliteal or isolated infrapopliteal disease (OR 1.42 [1.18-1.70], p=<0.001). This association between NLR and severe multi-level PAD remained significant even after adjustment for age (OR 1.31 [1.09-1.58], p=0.004); age, sex, race, and body mass index (OR 1.27 [1.05-1.5], p=0.015); and age, sex, race, body mass index, hypertension, diabetes, coronary artery disease, and creatinine (OR 1.25 [1.03-1.53], p=0.024). In patients who underwent endovascular intervention (n=523), there was no significant difference in the rate of target vessel revascularization on follow-up across tertiles of NLR (1st tertile 14.8%, 2nd tertile 14.1%, 3rd tertile 20.1%; p= 0.32). Conclusion: In a contemporary cohort of patients undergoing peripheral angiography with possible endovascular intervention, elevated NLR was independently associated with severe multi-level PAD

The cardioprotective mechanisms of colchicine in patients with stable ischemic heart disease remain uncertain. We tested varying concentrations of colchicine on platelet activity in vitro and a clinically relevant 1.8-mg oral loading dose administered over 1 h in 10 healthy subjects. Data are shown as median [interquartile range]. Colchicine addition in vitro decreased light transmission platelet aggregation only at supratherapeutic concentrations but decreased monocyte- (MPA) and neutrophil-platelet aggregation (NPA) at therapeutic concentrations. Administration of 1.8 mg colchicine to healthy subjects had no significant effect on light transmission platelet aggregation but decreased the extent of MPA (28 % [22-57] to 22 % [19-31], p = 0.05) and NPA (19 % [16-59] to 15 % [11-30], p = 0.01), platelet surface expression of PAC-1 (370 mean fluorescence intensity (MFI) [328-555] to 333 MFI [232-407], p = 0.02) and P-selectin (351 MFI [269-492] to 279 [226-364], p = 0.03), and platelet adhesion to collagen (10.2 % [2.5-32.6] to 2.0 % [0.2-9.5], p = 0.09) 2 h post-administration. Thus, in clinically relevant concentrations, colchicine decreases expression of surface markers of platelet activity and inhibits leukocyte-platelet aggregation but does not inhibit homotypic platelet aggregation.

OPINION STATEMENT: Hyperglycemia in the setting of coronary revascularization is associated with increased adverse cardiovascular events in patients with or without diabetes mellitus. Data suggest that acute peri-procedural hyperglycemia causes an increase in inflammation, platelet activity, and endothelial dysfunction and is associated with plaque instability and infarct size. While peri-procedural blood glucose level is an independent predictor of adverse outcomes in patients undergoing coronary revascularization, treatment strategies remain uncertain. Randomized clinical trials of glucose-insulin-potassium infusions have consistently shown no benefit, while those comparing insulin therapy versus standard of care have demonstrated mixed results, likely due to the failure to reach euglycemia with these strategies. Although no glucose-lowering agent has been shown to be superior in peri-procedural glycemic control, the continuation of clinically prescribed long-acting glucose-lowering medications in patients with diabetes mellitus prior to coronary angiography and possible percutaneous coronary intervention may be the simplest and most effective approach to maintain euglycemia and decrease the associated increase in inflammation and platelet activity. However, alternative strategies such as therapies targeted at the underlying mechanism of harm (e.g., more potent anti-platelet therapy, anti-inflammatory therapy) should also be considered and warrant further investigation.

PURPOSE: Perfusion analysis from first-pass contrast enhancement kinetics requires modeling tissue contrast exchange. This study presents a new approach for numerical implementation of the tissue homogeneity model, incorporating flexible distance steps along the capillary (NTHf). METHODS: The proposed NTHf model considers contrast exchange in fluid packets flowing along the capillary, incorporating flexible distance steps, thus allowing more efficient and stable calculations of the transit of tracer through the tissue. We prospectively studied 8 patients (62 +/- 13 years old) with suspected CAD, who underwent first-pass perfusion CMR imaging at rest and stress prior to angiography. Myocardial blood flow (MBF) and myocardial perfusion reserve index (MPRI) were estimated using both the NTHf and the conventional adiabatic approximation of the TH models. Coronary artery lesions detected at angiography were clinically assigned to one of three categories of stenosis severity ('insignificant', 'mild to moderate' and 'severe') and related to corresponding myocardial territories. RESULTS: The mean MBF (ml/g/min) at rest/stress and MPRI were 0.80 +/- 0.33/1.25 +/- 0.45 and 1.68 +/- 0.54 in the insignificant regions, 0.74 +/- 0.21/1.09 +/- 0.28 and 1.54 +/- 0.46 in the mild to moderate regions, and 0.79 +/- 0.28/0.63 +/- 0.34 and 0.85 +/- 0.48 in the severe regions, respectively. The correlation coefficients of MBFs at rest/stress and MPRI between the NTHf and AATH models were r = 0.97/0.93 and r = 0.91, respectively. CONCLUSIONS: The proposed NTHf model allows efficient quantitative analysis of the transit of tracer through tissue, particularly at higher flow. Results of initial application to MRI of myocardial perfusion in CAD are encouraging.