Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 17 Dec 2021

The Impact of Seasonality on Prosthetic Arteriovenous Vascular Access Graft Thrombosis

MD(Melit), MRCS(Edin.), MSc Adv. Surg. Prac(Cardiff), ChM Vasc(Edin.) and
MD FRCS(Edin.), MMed(Dund.), MD(Aberd.) FFStEd
Page Range: 35 – 43
DOI: 10.2309/JAVA-D-21-00022
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Highlights

  • No evidence of seasonal variation of arteriovenous graft (AVG) thrombosis.

  • No correlation between AVG thrombosis and changes in atmospheric temperature.

  • No correlation between AVG thrombosis and seasonal changes in relative humidity.

Abstract

Introduction:

Arteriovenous prosthetic grafts are susceptible to recurrent thrombotic occlusions mainly due to venous outflow disease secondary to neointimal hyperplasia. Maintenance of vascular access for dialysis is a perpetual challenge for both patients and health care systems. In regions with hotter climates, there is a clinical impression that episodes of prosthetic arteriovenous vascular access graft thrombosis are more frequent during hot dry summers secondary to dehydration and increased blood viscosity. Seasonality of thrombotic events has been observed in multiple vascular beds. However, a seasonal pattern or any association of arteriovenous graft thrombosis with temperature and relative humidity levels has never been fully demonstrated.

Methods:

Data were collected prospectively from January 2014 until December 2020 but analyzed retrospectively. In this 7-year timeframe, 289 episodes of arteriovenous graft thrombosis were identified from 142 grafts fashioned.

Results:

No monthly variation (P = 0.35) or seasonal variation (P = 0.91) was identified. No statistically significant correlation between episodes of thrombosis and mean monthly temperature and mean relative humidity was noted.

Conclusion:

No evidence was identified to support this theory. However, multiple issues with assessments of events must be conceded. Graft thrombosis is multifactorial in nature, and venous outflow disease contributes toward a significant number of these events. Within our local cohort, a low primary patency rate was identified, which further contributes to graft interventions. Relatively small numbers were recruited, and therefore, potential correlations could have been missed.

Keywords: arteriovenous graft; seasonality; temperature; humidity; thrombosis
Copyright: Copyright © 2022 Association for Vascular Access. All rights reserved.
Figure 1.
Figure 1.

Kaplan-Meier curve showing the long-term survival of prosthetic arteriovenous grafts.

Figure 2.
Figure 2.

Number of arteriovenous graft thromboses by year (analysis of variance test P = 0.35).

Figure 3.
Figure 3.

Number of arteriovenous graft thromboses by season.

Figure 4.
Figure 4.

Number of arteriovenous graft thromboses by month (analysis of variance test P = 0.53), showing trends of temperature and mean relative humidity per month.

Figure 5.
Figure 5.

Association between the episodes of arteriovenous graft thrombosis and mean temperatures per month.

Figure 6.
Figure 6.

Association between the episodes of arteriovenous graft thrombosis and mean relative humidity per month.

Figure 7.
Figure 7.

Minimum and maximum temperature in the studies assessing for vascular access thrombosis.

Contributor Notes

Correspondence concerning this article should be addressed to stefan.zammit@gov.mt
Received: 19 Sept 2021
Accepted: 09 Oct 2021
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