Radial artery achieves better flowmetric results than saphenous vein in the elderly

Improving coronary artery bypass grafting: a systematic review and meta-analysis on the impact of adopting transit-time flow measurement

Despite there being numerous studies of intraoperative graft flow assessment by transit-time flow measurement (TTFM) on outcomes after coronary artery bypass grafting (CABG), the adoption of contemporary TTFM is low. Therefore, on 31 January 2018, a systematic literature search was performed to identify articles that reported (i) the amount of grafts classified as abnormal or which were revised or (ii) an association between TTFM and outcomes during follow-up. Random-effects models were used to create pooled estimates with 95% confidence intervals (CI) of (i) the rate of graft revision per patient, (ii) the rate of graft revision per graft and (iii) the rate of graft revision among grafts deemed abnormal based on TTFM parameters. The search yielded 242 articles, and 66 original articles were included in the systematic review. Of those articles, 35 studies reported on abnormal grafts or graft revisions (8943 patients, 15 673 grafts) and were included in the meta-analysis. In 4.3% of patients (95% CI 3.3–5.7%, I² = 73.9) a revision was required and 2.0% of grafts (95% CI 1.5–2.5%; I²=66.0) were revised. The pooled rate of graft revisions among abnormal grafts was 25.1% (95% CI 15.5–37.9%; I²=80.2). Studies reported sensitivity ranging from 0.250 to 0.457 and the specificity from 0.939 to 0.984. Reported negative predictive values ranged from 0.719 to 0.980 and reported positive predictive values ranged from 0.100 to 0.840. This systematic review and meta-analysis showed that TTFM could improve CABG procedures. However, due to heterogeneous data, drawing uniform conclusions appeared challenging. Future studies should focus on determining the optimal use of TTFM and assessing its diagnostic accuracy.

WALL SHEAR AND CIRCUMFERENTIAL STRESS CHANGES IN A PORCINE DOUBLE-LAYER VEIN GRAFT

This study aimed to evaluate short-term changes of wall shear stress and circumferential stress in a self-designed double-layer vein graft in a porcine vein graft model. In this study, left and right hind femoral arteries of 40 white pigs were randomly divided into an experimental group (double-layer vein graft) and a control group (single-layer vein graft). At one hour and then at one, two and four weeks after venous bypass grafting, sets of ten animals underwent Doppler-ultrasonic and electromagnetic flowmeter examinations to calculate wall shear stress in middle sections of the vein grafts. Then, the vein grafts were excised and subjected to mechanical tests to assess the circumferential stress. As a result, the double-layer vein grafts showed an increase in wall shear stress by 43.5% compared with the control group at one hour after venous bypass grafting. With time wall shear stress gradually increased, the intimal circumferential stress gradually decreased in the two groups. Intimal circumferential stress in the experimental group was significantly lower than that in the control group at each observational time-point. Hence, the double-layer support of the vein graft may have contributed towards a rise in wall shear stress and reduction in circumferential stress in the true vein graft over the four-week period after venous bypass grafting, and thus conferring some protection to the true vein graft.

Coronary artery surgery in octogenarians: evolving strategies for the improvement in early and late results

The purpose of this study was to investigate retrospectively early and late outcomes of coronary artery bypass grafting (CABG) in a large series of octogenarians. We retrospectively reviewed the data of 241 octogenarian patients who underwent CABG between April 2002 and April 2009 at our institution. Mean age was 84.7 ± 1.8 years. Patients affected by concomitant coexistent organic aortic, mitral, or tricuspid valve disease were excluded from the study. Patients with functional secondary ischemic mitral incompetence were included in the study. The majority of the patients were male. Angina pectoris functional class III/IV accounted for 164 patients (68%). Left ventricular ejection fraction ≤35% was diagnosed in 38 patients (15.8%). Early mortality rate was 5.8% (14 patients). Causes of death were cardiac related in 10 patients. Preoperative independent predictors of in-hospital mortality obtained with multivariate analysis were extracardiac arteriopathy, New York Heart Association class III/IV, and previous percutaneous transluminal coronary angioplasty (PTCA). The overall mean follow-up was 41.6 ± 25.9 months (range 1-87.6 months). Among the 222 contacted survivors, there were 16 (7.2%) deaths during the follow-up. The actuarial survival was 91.9% at 1 year and 83.5% at 5 years. On multivariate analysis, time to late death was adversely affected by preoperative extracardiac arteriopathy and previous PTCA. Advanced age alone should not be a deterrent for CABG if it has been determined that the benefits outweigh the potential risk. A careful selection of optimal candidates, based on the evaluation of their systemic comorbidities, appears mandatory in order to obtain the greatest benefit for these high-risk patients.