'Tardus-Parvus' waveform

Effect of left colonic artery preservation on perfusion at the anastomosis in rectal cancer surgery evaluated with intraoperative ultrasound

PURPOSE

Intraoperative ultrasound was used to assess the flow velocity in the marginal vessel arch adjacent to the anastomosis, critical for evaluating the anastomotic blood supply. This technique also enabled us to investigate the potential effects of preserving the left colonic artery on the perfusion of the anastomosis.

METHODS

This prospective study included 40 rectal cancer patients who underwent laparoscopic anterior resection between January 2021 and January 2023. The length of the inferior mesenteric artery (IMA) was measured from its origin to the first branch, and the diameters of the mesenteric vessel IMA, left colonic artery (LCA), and marginal mesenteric artery (MMA) were recorded. Blood flow velocity and Doppler ultrasound waveforms of the MMA near the anastomosis were collected. Measurements were taken both before and after clamping the IMA using atraumatic forceps. The tardus parvus pattern of the MMA ultrasound waveforms was recorded to evaluate the hypoperfusion status of the anastomosis.

RESULTS

The mean velocities of MMA were 47.9 cm/s before clamping and 34.9 cm/s after atraumatic clamping, indicating significant differences (p < 0.05). Thirteen patients (32.5%) exhibited a Tardus parvus pattern after IMA atraumatic clamping. Multivariate analysis revealed older age and LCA diameter as independent clinical predictors of the hypoperfusion status after IMA clamping.

CONCLUSIONS

Preservation of the LCA may improve perfusion near the anastomosis during rectal cancer surgery. Older age and LCA diameter can be considered useful predictors of the mesenteric hypoperfusion status after IMA ligation. Intraoperative ultrasound can evaluate the perfusion of the MMA near the anastomosis. Chinese Clinical Trial Registry-Registration number: ChiCTR2000041475.