Saphenous Vein Graft Failure: From Pathophysiology to Prevention and Treatment Strategies

Predictors of vein graft disease progression between one week and one year after surgical coronary revascularization: Impact of secondary prevention medications

OBJECTIVE

This study aimed to detect the predictors of vein graft disease (VGD) progression between 1 week and 1 year after surgery and to evaluate the impact of secondary prevention medications.

METHODS

A total of 218 consecutive patients underwent surgical coronary revascularization were evaluated by coronary computed tomography angiography both at 1-week and 1-year follow-up. Logistic regression analyses were performed to investigate the predictors of VGD progression. A risk score (0-4) was set up to evaluate implementation result of secondary prevention measures according to 1-year follow-up result. Association between VGD progression and the risk score was assessed.

RESULTS

VGD progression occurred in 11.3% of saphenous vein grafts (SVG) and 22.1% of patients. At the patient level, poor vein graft (odds ratio [OR] = 4.25), noncontrolled hyperlipidemia (OR = 3.01), and diabetes mellitus (DM) (OR = 2.96) were predictors, while diameter of SVG (mm, OR = 0.35) was protective factor. At the graft level, DM (OR = 3.52), noncontrolled hyperlipidemia (OR = 2.33), and peripheral artery disease (PAD) (OR = 2.20) were predictors, while number of SVGs (OR = 0.63), diameter of SVG (mm, OR = 0.39), and mean graft flow >25 ml/min (OR = 0.35) were protective factors. VGD progression was significantly associated with the risk score at both the patient (OR = 1.52) and the graft level (OR = 1.38).

CONCLUSIONS

Poor vein graft, noncontrolled hyperlipidemia and DM were predictors of VGD progression between 1 week and 1 year after surgery at the patient level, while larger SVG diameter was a protective factor. DM, PAD and noncontrolled hyperlipidemia were predictors at the graft level, while a number of SVGs, larger SVG diameter, and mean graft flow >25 ml/min were protective factors. Implementation failure of secondary prevention medications was associated with VGD progression from as early as 1 year after surgery.

Association of Dual Antiplatelet Therapy With Ticagrelor With Vein Graft Failure After Coronary Artery Bypass Graft Surgery: A Systematic Review and Meta-analysis

IMPORTANCE

The role of ticagrelor with or without aspirin after coronary artery bypass graft surgery remains unclear.

OBJECTIVE

To compare the risks of vein graft failure and bleeding associated with ticagrelor dual antiplatelet therapy (DAPT) or ticagrelor monotherapy vs aspirin among patients undergoing coronary artery bypass graft surgery.

DATA SOURCES

MEDLINE, Embase, and Cochrane Library databases from inception to June 1, 2022, without language restriction.

STUDY SELECTION

Randomized clinical trials (RCTs) comparing the effects of ticagrelor DAPT or ticagrelor monotherapy vs aspirin on saphenous vein graft failure.

DATA EXTRACTION AND SYNTHESIS

Individual patient data provided by each trial were synthesized into a combined data set for independent analysis. Multilevel logistic regression models were used.

MAIN OUTCOMES AND MEASURES

The primary analysis assessed the incidence of saphenous vein graft failure per graft (primary outcome) in RCTs comparing ticagrelor DAPT with aspirin. Secondary outcomes were saphenous vein graft failure per patient and Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding events. A supplementary analysis included RCTs comparing ticagrelor monotherapy with aspirin.

RESULTS

A total of 4 RCTs were included in the meta-analysis, involving 1316 patients and 1668 saphenous vein grafts. Of the 871 patients in the primary analysis, 435 received ticagrelor DAPT (median age, 67 years [IQR, 60-72 years]; 65 women [14.9%]; 370 men [85.1%]) and 436 received aspirin (median age, 66 years [IQR, 61-73 years]; 63 women [14.5%]; 373 men [85.5%]). Ticagrelor DAPT was associated with a significantly lower incidence of saphenous vein graft failure (11.2%) per graft than was aspirin (20%; difference, -8.7% [95% CI, -13.5% to -3.9%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001) and was associated with a significantly lower incidence of saphenous vein graft failure per patient (13.2% vs 23.0%, difference, -9.7% [95% CI, -14.9% to -4.4%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001). Ticagrelor DAPT (22.1%) was associated with a significantly higher incidence of BARC type 2, 3, or 5 bleeding events than was aspirin (8.7%; difference, 13.3% [95% CI, 8.6% to 18.0%]; OR, 2.98 [95% CI, 1.99 to 4.47]; P < .001), but not BARC type 3 or 5 bleeding events (1.8% vs 1.8%, difference, 0% [95% CI, -1.8% to 1.8%]; OR, 1.00 [95% CI, 0.37 to 2.69]; P = .99). Compared with aspirin, ticagrelor monotherapy was not significantly associated with saphenous vein graft failure (19.3% vs 21.7%, difference, -2.6% [95% CI, -9.1% to 3.9%]; OR, 0.86 [95% CI, 0.58 to 1.27]; P = .44) or BARC type 2, 3, or 5 bleeding events (8.9% vs 7.3%, difference, 1.7% [95% CI, -2.8% to 6.1%]; OR, 1.25 [95% CI, 0.69 to 2.29]; P = .46).

CONCLUSIONS AND RELEVANCE

Among patients undergoing coronary artery bypass graft surgery, adding ticagrelor to aspirin was associated with a significantly decreased risk of vein graft failure. However, this was accompanied by a significantly increased risk of clinically important bleeding.

Trends and Outcomes of Myocardial Infarction in Patients With Previous Coronary Artery Bypass Surgery

Data on myocardial infarction (MI) treatment in patients with previous coronary artery bypass grafting (CABG) is limited. We queried the Nationwide Readmissions Database to identify hospitalizations of patients with MI from 2016 to 2019. Among hospitalized patients presenting with MI, 10.3% had previous CABG. Patients with MI who had previous CABG were less likely to be revascularized than those without previous CABG for both ST-segment elevation MI (STEMI) (46.4% vs 68.4%) and non-ST-segment elevation MI (NSTEMI) (30.8% vs 36.7%). CABG was associated with a lower risk of death in NSTEMI patients (odds ratio [OR] 0.84, 95% confidence interval [CI] 0.82 to 0.86), but a higher risk in STEMI patients (OR 1.06, 95% CI 1.01 to 1.13). Revascularization was associated with a lower risk of in-hospital death in patients with previous CABG presenting with STEMI (OR 0.30, 95% CI 0.26 to 0.35) and NSTEMI (OR 0.21, 95% CI 0.19 to 0.23).

Bioengineering Human Tissues and the Future of Vascular Replacement

Cardiovascular defects, injuries, and degenerative diseases often require surgical intervention and the use of implantable replacement material and conduits. Traditional vascular grafts made of synthetic polymers, animal and cadaveric tissues, or autologous vasculature have been utilized for almost a century with well-characterized outcomes, leaving areas of unmet need for the patients in terms of durability and long-term patency, susceptibility to infection, immunogenicity associated with the risk of rejection, and inflammation and mechanical failure. Research to address these limitations is exploring avenues as diverse as gene therapy, cell therapy, cell reprogramming, and bioengineering of human tissue and replacement organs. Tissue-engineered vascular conduits, either with viable autologous cells or decellularized, are the forefront of technology in cardiovascular reconstruction and offer many benefits over traditional graft materials, particularly in the potential for the implanted material to be adopted and remodeled into host tissue and thus offer safer, more durable performance. This review discusses the key advances and future directions in the field of surgical vascular repair, replacement, and reconstruction, with a focus on the challenges and expected benefits of bioengineering human tissues and blood vessels.