Total Arterial Revascularization: Evaluating the Length of the Radial Artery in a Composite Graft Configuration

PURPOSE

Reimplanting the radial artery in the left internal thoracic artery as a composite graft allows total arterial revascularization (TAR) without aortic manipulation. The limitation of this strategy is the length of the radial artery required to reach distal right coronary artery (RCA) branches. Our analysis focuses on the feasibility of this strategy.

METHODS

A total of 169 patients underwent TAR using the radial artery in a composite grafting configuration. Length of the radial artery, number of sequential anastomoses, heart size, target location, length of the arm, patient height, body surface area, and flow in the composite graft were prospectively collected.

RESULTS

The mean length of the radial artery was 18.02 cm. Patients with a mean length of the radial artery of 15.9 cm needed an extension of the radial artery with another conduit to reach the RCA distal branches. When T-configuration is used, the length of the radial artery should be 0.53 cm per sequential anastomosis to reach the RCA distal branches.

CONCLUSIONS

Our study shows that an average length of 18.02 cm of radial artery is needed to reach targets on the RCA distal branches in composite grafting. In T-configuration, we need 0.53 cm more length per anastomosis to achieve TAR.

Impact of prediabetes and duration of diabetes on radial artery atherosclerosis in acute coronary syndrome patients: An optical coherence tomography study

BACKGROUND

Prediabetes (PDM) and diabetes mellitus (DM) are common among acute coronary syndrome (ACS) patients. The present study evaluated the association between diabetes status and radial artery (RA) atherosclerosis using optical coherence tomography (OCT) in ACS patients.

METHODS

A total of 335 ACS patients who underwent RA OCT were categorized into the DM group, the PDM group, and the normal glucose metabolism (NGM) group. OCT characteristics and clinical variables were compared.

RESULTS

RA atherosclerotic plaques were more frequent in the PDM and DM groups than in the NGM group (38.7% vs. 33.3% vs. 16.1%, p = 0.001). Lipid and calcified plaque occurrence were significantly more common in the DM group, followed by the PDM and NGM groups (19.3% vs. 14.6% vs. 6.5%, p = 0.027; 11.8% vs. 6.5% vs. 1.1%, p = 0.009). The prevalence of microvessels in the PDM group was significantly higher (42.7% vs 23.7%, p = 0.017) than in the NGM group but was comparable to the DM group. Multivariate analysis revealed that HbA1c level and age were independent predictors of RA plaque formation and eccentric intimal hyperplasia (all p<0.05).

CONCLUSIONS

RA atherosclerosis characteristics differ according to diabetes status. HbA1c level could be a useful marker for RA atherosclerosis progression in ACS patients.

First, do no harm: bilateral radial artery occlusion in a COVID-19 patient

Objective

Objective of this case report is to draw attention to a less known thrombotic complication associated with COVID-19, i.e., thrombosis of both radial arteries, with possible (long-term) consequences.

The Case

In our COVID-19 ICU a 49-year-old male patient was admitted, with past medical history of obesity, smoking and diabetes, but no reported atherosclerotic complications. The patient had been admitted with severe hypoxemia and multiple pulmonary emboli were CT-confirmed. ICU-treatment included mechanical ventilation and therapeutic anticoagulation. Preparing the insertion of a new radial artery catheter for invasive blood pressure measurement and blood sampling, we detected that both radial arteries were non-pulsating and occluded: (a) Sonography showed the typical anatomical localization of both radial and ulnar arteries. However, Doppler-derived flow-signals could only be obtained from the ulnar arteries. (b) To test collateral arterial supply of the hand, a pulse-oximeter was placed on the index finger. Thereafter, the ulnar artery at the wrist was compressed. This compression caused an immediate loss of the finger’s pulse-oximetry perfusion signal. The effect was reversible upon release of the ulnar artery. (c) To test for collateral perfusion undetectable by pulse-oximetry, we measured regional oxygen saturation (rSO₂) of the thenar muscle by near-infrared spectroscopy (NIRS). Confirming our findings above, ulnar arterial compression demonstrated that thenar rSO₂ was dependent on ulnar artery flow. The described development of bilateral radial artery occlusion in a relatively young and therapeutically anticoagulated patient with no history of atherosclerosis was unexpected.

Conclusions

Since COVID-19 patients are at increased risk for arterial occlusion, it appears advisable to meticulously check for adequacy of collateral (hand-) perfusion, avoiding the harm of hand ischemia if interventions (e.g., catheterizations) at the radial or ulnar artery are intended.

Is the result of modified Allen’s test still accurate after endoscopic thoracic sympathectomy?

Background

The radial artery (RA) is increasingly being used for coronary artery bypass grafting (CABG). Endoscopic thoracic sympathectomy (ETS) has been shown to block innervation of sympathetic nerves of upper limbs, which reduces sweating of hands and dilates blood vessels. The modified Allen’s test (MAT) is one of the commonest methods of assessing collateral arm flow prior to RA harvest, though it has limitations. However, the reliability of MAT after ETS remains unclear. We therefore investigated the effects of ETS on the results of MAT.

Methods

A retrospective cohort study was conducted on 164 consecutive Chinese patients with palmar hyperhidrosis who underwent ETS between January 2016 and January 2019. The medical records were reviewed concerning the ultrasound examination and MAT results of their RAs and ulnar arteries (UAs) in both forearms before and after ETS.

Results

The performance of ETS significantly increased the diameter of the right RA from 2.731±0.122 to 3.102±0.114 mm in men and from 2.347±0.074 to 2.915±0.162 mm in women. Similar effects of ETS were observed in expanding the diameters of the left RA and the UA. Meanwhile, there was no significant effect of ETS on systolic blood pressure (BP) and heart rate (HR). Overall, retesting of patients following ETS with a preoperative positive MAT result revealed a transition to a negative result.

Conclusions

ETS was effective in dilating RA in both men and women, which could lead to a false negative preoperative MAT result. Patients should be questioned about their history of ETS if their RAs are to be harvested for CABG. More studies are warranted to evaluate the safety of RA as a coronary artery graft after ETS.