External stenting of saphenous vein grafts for coronary artery bypass: a single-center analysis of clinical outcomes

BACKGROUND

Angiographic studies have shown that external stenting reduces disease progression in saphenous vein grafts (SVG) for coronary artery bypass grafting (CABG). However, reports of clinical outcomes of external SVG stenting are limited.

METHODS

We conducted a retrospective analysis using a prospectively maintained national registry to evaluate clinical outcomes in patients undergoing either isolated CABG or combined (CABG + valve) procedures with use of an external SVG stent between December 2015 and December 2019. Median follow-up was 36.2 months (IQR: 24.4-41.6 months). The primary endpoint was ischemia-driven target vessel revascularization at 1 year. Secondary endpoints included all-cause death, non-fatal myocardial infarction (MI), stroke, and the composite of death, non-fatal MI or stroke at 1 year. Kaplan-Meier rates of survival, freedom from the composite of death, non-fatal MI or stroke and freedom from repeat revascularization were calculated at 3 years.

RESULTS

The study population included 74 patients (isolated CABG, N.=61; combined procedure, N.=13). Mean age was 65.5±9.2 years, and 81% were male. External stenting of one SVG was performed in 63 patients (85%) and external stenting of 2 SVG in 11 patients (15%). External stenting was most frequently performed on an SVG to the right coronary artery (N.=45 patients; 53%). Ischemia-driven target-vessel revascularization occurred in 0% at 1 year. All-cause death, MI, stroke, and the composite of death, MI, or stroke at 1 year occurred in 2.7% (2/74), 0% (0/74), 1.4% (1/74), and 4.1% (3/74), respectively. At 3 years, the rates of survival, freedom from the composite of death, non-fatal MI or stroke, and freedom from repeat revascularization were 89.7% (95% CI: 78.0-95.3), 88.3% (95% CI: 76.5-94.4), and 94.8% (95% CI: 84.6-98.3), respectively.

CONCLUSIONS

Clinical outcomes with external SVG stenting are excellent without ischemia-driven target-vessel revascularization at 1 year, and low rates of repeat revascularization at 3 years. Further follow-up will show whether external stenting reduces SVG failure with a benefit on long-term clinical outcomes.

Neutrophil Activation/Maturation Markers in Chronic Heart Failure with Reduced Ejection Fraction

BACKGROUND

Neutrophils are critically involved in the immune response. Inflammatory stimuli alter the expression status of their surface molecule toolset, while inflammation-stimulated granulopoiesis might also influence their maturation status. Data on neutrophil status in heart failure with reduced ejection fraction (HFrEF) are scarce. The present study aims to evaluate the role of neutrophil CD11b, CD66b and CD64 expression in HFrEF.

METHODS

A total of 135 HFrEF patients and 43 controls were recruited. Mean fluorescence intensity of the activation/maturation markers CD11b, CD66b and CD64 was measured on neutrophils by flow cytometry. CD10 (neprilysin) expression was simultaneously determined.

RESULTS

Neutrophil CD64 expression was higher in HFrEF compared with controls, while CD11b/CD66b levels were similar. Neutrophil CD11b and CD66b showed a significant direct correlation to neutrophil CD10 expression (rs = 0.573, p < 0.001 and rs = 0.184, p = 0.033). Neutrophil CD11b and CD66b correlated inversely with heart failure severity reflected by NT-proBNP and NYHA class (NT-proBNP: rs = -0.243, p = 0.005 and rs = -0.250, p = 0.004; NYHA class: p = 0.032 and p = 0.055), whereas no association for CD64 could be found. Outcome analysis did not reveal a significant association between the expression of CD11b, CD66b and CD64 and all-cause mortality (p = ns).

CONCLUSIONS

The results underline the potential role of neutrophils in HFrEF disease pathophysiology and risk stratification and should stimulate further research, characterizing subpopulations of neutrophils and searching for key molecules involved in the downward spiral of inflammation and heart failure.

Relevance of Neutrophil Neprilysin in Heart Failure

Significant expression of neprilysin (NEP) is found on neutrophils, which present the transmembrane integer form of the enzyme. This study aimed to investigate the relationship of neutrophil transmembrane neprilysin (mNEP) with disease severity, adverse remodeling, and outcome in HFrEF. In total, 228 HFrEF, 30 HFpEF patients, and 43 controls were enrolled. Neutrophil mNEP was measured by flow-cytometry. NEP activity in plasma and blood cells was determined for a subset of HFrEF patients using mass-spectrometry. Heart failure (HF) was characterized by reduced neutrophil mNEP compared to controls (p < 0.01). NEP activity on peripheral blood cells was almost 4-fold higher compared to plasma NEP activity (p = 0.031) and correlated with neutrophil mNEP (p = 0.006). Lower neutrophil mNEP was associated with increasing disease severity and markers of adverse remodeling. Higher neutrophil mNEP was associated with reduced risk for mortality, total cardiovascular hospitalizations, and the composite endpoint of both (p < 0.01 for all). This is the first report describing a significant role of neutrophil mNEP in HFrEF. The biological relevance of neutrophil mNEP and exact effects of angiotensin-converting-enzyme inhibitors (ARNi) at the neutrophil site have to be determined. However, the results may suggest early initiation of ARNi already in less severe HF disease, where effects of NEP inhibition may be more pronounced.

Neutrophil neprilysin expression correlates with inflammatory activation in chronic HFrEF patients

Background

Inhibition of neprilysin by the angiotensin receptor-neprilysin inhibitor has shown remarkable success in the treatment of heart failure with reduced ejection fraction (HFrEF). However, the exact mechanism of action is still a matter of debate. Neprilysin (NEP) is a ubiquitous transmembrane endopeptidase markedly expressed on the cell surface of neutrophils, in this context also known as CD10. Originally, CD10 has been identified as a cell surface marker to discriminate mature from immature neutrophils. Other inflammatory neutrophil surface markers such as CD11b, CD64 and CD66b are commonly used to determine the activation status of neutrophils. In our previous explorative study, NEP expression on neutrophils correlated inversely with HF severity and mortality. This study aimed to explore the relationship between NEP expression and typical neutrophil activation markers and to confirm its relation to HF severity reflected by NT-proBNP and NYHA class in a bigger cohort of HFrEF patients.

Methods

We prospectively enrolled 208 consecutive patients with stable HFrEF. Mean fluorescence intensity (MFI) of CD10 expression on peripheral blood neutrophils was determined by flow cytometry of whole blood samples. In addition, for a subset of 117 patients the expression of CD11b, CD64 and CD66b was measured. EDTA anticoagulated blood (100 μl) was stained using a combination of six antibodies with fluorescence minus one sample as control [CD10 (#332777), CD45 (#560178), CD16 (#335035), CD11b (#555388), CD64 (#561191), CD66b (#562254); BD Biosciences, San Jose, CA, USA].

Results

Median age was 64 years (IQR 54–72), 57 (27%) patients were female. Median NT-proBNP values were 1819 pg/ml (IQR 740–4264). Approximately half of the study population with 115 (55.3%) patients had a non-ischemic etiology of HF. Median MFI of NEP (CD10) on neutrophils was 5542 (IQR 4168–6903). Neutrophil NEP expression decreased with HF severity reflected by NYHA stage (p=0.006) and tertiles of NT-proBNP (p=0.003). Interestingly, non-ischemic HFrEF was characterized by higher neutrophil NEP expression compared to ischemic HFrEF [5703 (IQR 4548–7235) vs 4994 (IQR 3844–6718), p=0.018]. Neutrophil NEP expression correlated highly significant with CD11b expression (r=0.61, p&lt;0.001) but not with CD64 and CD66b [p=ns] (Figure 1).

Conclusion

These data support the evidence for an inverse correlation of neutrophil NEP expression with HF severity in stable HFrEF patients and for NEP upregulation on neutrophils in patients with non-ischemic cardiomyopathy. There was a strong relationship between neutrophil NEP regulation and the activation marker CD11b, proposing a link between the neutrophil NEP compartment and systemic inflammatory response.

Figure 1

Funding Acknowledgement

Type of funding source: None