Patient and haemodynamic factors affecting intraoperative graft flow during coronary artery bypass grafting: an observational pilot study

How to harvest the left internal mammary artery-a randomized controlled trial

OBJECTIVES

It is uncertain whether Thunderbeat has a place in harvesting the left internal mammary artery (LIMA) and whether skeletonization is superior to pedicle-harvested LIMA. Some investigations have shown improved flowrates in the skeletonized graft. The aim of this study was to compare 3 groups of harvesting techniques: Pedicled, surgical skeletonized and skeletonized with Thunderbeat in terms of flow rates in the LIMA and postoperative in-hospital outcomes.

METHODS

Patients undergoing coronary artery bypass grafting with the LIMA to the anterior descending artery were randomized to pedicled (n = 56), surgical skeletonized (n = 55) and skeletonized with Thunderbeat (n = 54). Main outcomes were blood flow and pulsatility index in the graft.

RESULTS

No statistical difference between groups regarding flow in LIMA or pulsatility index. Similarly, no difference in postoperative bleeding or days of hospitalization. The duration of harvesting was faster for the pedicled technique compared with surgical skeletonized and skeletonized with Thunderbeat [mean total min: pedicled 20.2 min standard deviation (SD) ± 5.4; surgical skeletonized 28.6 min SD ± 8.7; skeletonized with Thunderbeat 28.3 min SD ± 9.11, P < 0.001]. No grafts discarded due to faulty harvesting and there was no graft failure within hospital stay.

CONCLUSIONS

We found no difference between the harvesting methods except for a significantly faster harvesting time with the pedicled technique. However, non-touch skeletonized LIMA harvesting with Thunderbeat seems to be an effective alternative to traditional surgical skeletonized LIMA. The future will reveal whether patency is harvesting dependent.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05562908.

Meta-analysis of haematocrit and activated partial thromboplastin time as risk factors for unplanned interruptions in patients undergoing continuous renal replacement therapy

OBJECTIVE

Although continuous renal replacement therapy (CRRT) is common, unplanned interruptions often limit its usefulness. Unplanned interruption refers to the forced interruption of blood purification treatment, the failure to complete blood purification treatment goals or the failure to meet blood purification schedule times. This study aimed to evaluate the effect of haematocrit and activated partial thromboplastin time (APTT) on the incidence of unplanned interruptions in critical patients with CRRT.

METHODS

A systematic review and a meta-analysis were performed by searching the databases of China National Knowledge Infrastructure, Wanfang, VIP, China Biomedical Literature, Cochrane Library, PubMed, Web of Science and Embase from their inception to 31st March 2022 for all studies with a comparator or independent variable relating to the unplanned interruption of CRRT.

RESULTS

Nine studies involving 1165 participants were included. Haematocrit and APTT were independent risk factors for the unplanned interruption of CRRT. The higher the haematocrit level, the greater the risk of unplanned CRRT interruptions (relative risk ratio [RR] = 1.04, 95% confidence interval [CI]: 1.02, 1.07, Z = 4.27, p < 0.001). The prolongation of APPT reduced the risk of unplanned CRRT interruptions (RR = 0.94, 95% CI: 0.92, 0.96, Z = 6.10, p < 0.001).

CONCLUSION

Haematocrit and APTT are the influencing factors on the incidence of unplanned interruptions in critical patients undergoing CRRT.

Intraoperative transit time flow measurements during off-pump coronary artery bypass surgery: The impact of coronary stenosis on competitive flow

BACKGROUND

Combining preoperative angiography findings with intraoperative transit time flow measurements (TTFM) may improve patency of coronary artery bypass grafts. Nevertheless, graft flow might be impaired by native coronary flow based on the severity of stenoses, with inferior long-term outcomes. This study investigates the impact of left anterior descending artery (LAD) stenosis on competitive flow measured in left internal mammary artery (LIMA) grafts during off-pump coronary artery bypass grafting.

METHODS

Fifty patients were included in this prospective single-center cohort study. LAD stenosis was assessed with quantitative coronary analysis (QCA) and stratified into three groups based on its severity. TTFM of LIMA grafts were performed with LAD open and temporarily occluded. Change in mean graft flow after LAD snaring was the primary endpoint. Secondary endpoints included further TTFM parameters, clinical outcomes, and competitive flow index (CFI), defined as the ratio of mean graft flow with open or closed LAD.

RESULTS

Mean LAD stenosis as objectified with QCA was 58 ± 15%. Mean LIMA graft flow increased from 20 ml/min with open LAD to 30 ml/min with snared LAD (p < .001). TTFM cut-off values for graft patency improved in 26%-42% of patients after LAD occlusion. Median CFI was 0.66 (IQR: 0.56-0.82). Postoperative myocardial infarction occurred in 2.0% of patients, 120-day mortality was 0%, and 2-year mortality was 6.0%.

CONCLUSIONS

Routine snaring of the LAD with CFI calculation during coronary artery bypass grafting is useful to detect significant competitive flow in LIMA grafts, potentially preventing unnecessary intraoperative graft revisions.

Transit time flow measurement of coronary bypass grafts before and after protamine administration

Background

Intraoperative graft assessment with tools like Transit Time Flow Measurement (TTFM) is imperative for quality control in coronary surgery. We investigated the variation of TTFM parameters before and after protamine administration to identify new benchmark parameters for graft quality assessment.

Methods

The database of the REQUEST (“REgistry for QUality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery”) study was retrospectively reviewed. A per graft analysis was performed. Only single grafts (i.e., no sequential nor composite grafts) where both pre- and post-protamine TTFM values were recorded with an acoustical coupling index > 30% were included. Grafts with incomplete data and mixed grafts (arterio-venous) were excluded. A second analysis was performed including single grafts only in the same MAP range pre- and post- protamine administration.

Results

After adjusting for MAP, we found a small increase in MGF (29 mL/min to 30 mL/min, p = 0.009) and decrease in PI (2.3 to 2.2, p <  0.001) were observed after the administration of protamine. These changes were especially notable for venous conduits and for CABG procedures performed on-pump.

Conclusion

The small changes in TTFM parameters observed before and after protamine administration seem to be clinically irrelevant, despite being statistically significant in aggregate. Our data do not support a need to perform TTFM measurements both before and after protamine administration. A single TTFM measurement taken either before or after protamine may suffice to achieve reliable data on each graft’s performance. Depending on the specific clinical situation and intraoperative changes, more measurements may be informative.

Trial registration

Clinical Trials Number: NCT02385344, registered February 17th, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01575-y.