Calcium phosphate product level as a predictor for arteriovenous fistula re-operations in patients with chronic renal failure

Objectives

There is an increased calcium phosphate product level causing the formation of calcification in the arterial wall and thus decreased quality of fistula in patients with chronic renal failure. The purpose of our study is to verify the relationship between arteriovenous fistula re-operation and high calcium phosphate product level.

Methods

Seventy-nine consecutive patients with chronic renal failure between April 2016 and February 2018 were included in the study. Patients having calcium phosphate product level ≥50 mg2/dl2 were defined as group 1, whereas those having <50 mg2/dl2 were defined as group 2. Primary outcome of interest was the need for re-operation during the follow-up and to determine the risk factors for re-operation. To determine independent predictors for re-operation, multivariate logistic regression model was used.

Results

The rates of redo and tredo operation were significantly higher in group 1 compared to group 2 ( p = 0.01 and 0.04). In multivariate analysis, phosphate (OR: 1.84, 95% CI: 1.00–3.40, p = 0.05) and triglyceride (OR: 1.01, 95% CI: 1.00–1.02, p = 0.04) levels for redo operation and calcium phosphate product level (OR: 1.11, 95% CI: 1.01–1.22, p = 0.03) for tredo operation were found to be independent predictors.

Conclusions

High calcium phosphate product level leads to increased risk of arteriovenous fistula re-operation by causing arterial stiffness in this patient group. Additionally, these re-operations place additional burden on morbidity and cost efficacy. Thus, we recommend keeping the calcium phosphate product level at the optimal level in these patients to avoid both the risk of arteriovenous fistula re-operation and the other cardiovascular problems.

Effect of moderate pressure distention on the human saphenous vein vasomotor function

BACKGROUND

Manual pressure distension, which is commonly applied to the human saphenous vein graft for coronary artery bypass, is believed to have detrimental consequences for the graft patency. The vasomotor function of the vein after distention during surgical preparation for grafting and after distention in laboratory conditions at pressure of 50 to 600 mm Hg was studied. The effect of a combination of vasodilative agents to prevent vasospasm was also tested.

METHODS

The contractile and dilatory responses of distended and undistended human saphenous veins and those after drug treatment were examined in organ baths under isometric conditions.

RESULTS

Distention at the pressure range 100 to 300 mm Hg resulted in an increased contractile response of the saphenous vein to both alpha-adrenergic activation with 50 micromol/L phenylephrine (153.73% +/- 15.69%) and depolarization with 80 mmol/L K(+) (141.03% +/- 15.13%) in comparison with the undistended vein and did not impair the relaxation. In contrast manual distention during surgical preparation abolished the contractile response and impaired the relaxation. The application of a combination of vasodilative drugs (alpha-adrenergic antagonist phenoxybenzamine, 10 micromol/L, Rho-kinase inhibitor HA-1077, 50 micromol/L, and calcium blocker nicardipine, 1 micromol/L) eliminated the contractile response of the vein to phenylephrine and 80 mmol/L K(+). This effect was sustained more than 20 hours after the washout of the drugs.

CONCLUSIONS

The distention of the human saphenous vein at moderate pressure combined with the application of the effective combination of vasodilative drugs before grafting into the arterial circulation could be a beneficial alternative to the current practice of uncontrolled pressure distension.