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Arteriovenous fistulae (AVF)/ arteriovenous grafts (AVGs) for haemodialysis (HD) are felt to be the best access option for HD. Thrombosis of AVF/AVG is a known complication and timely interventions to treat the thrombosis will improve the AVF/AVG survival and reduce the need for switching to a dialysis line and creating new dialysis access.
Percutaneous Mechanical Thrombectomy (PMT) with thrombolysis is one of the radiological techniques used for de-clotting AVFs. It can be done under sedation. Potential complications include vessel rupture, pulmonary embolism and hyperkalaemia.
Our protocol requires that the blood pressure (BP) before the PMT is <160/100mmHg. We observed that some patients had high BP at the start of PMT and the procedure was either deferred or delayed. In the literature, it is suggested that earlier the intervention on a thrombosed AVF or AVG, the better the outcome, so delays are not desirable.
We couldn’t find any published data about blood pressure variation in relation to PMT. We decided therefore to collect data on the variations in blood pressure in our patients prior to, during and after the PMT procedure. Our aim was to find out the magnitude of the change, possible aetiologies, potential management options and to increase the awareness of this issue.
Twenty one PMT procedures were performed in 19 patients between November 2021 and July 2023. Complete data were available in 18 patients and these were collected from electronic data records as follows:
A) Demographic characteristics - sex, age, dialysis access (AVF or AVG)
B) Mean and range of:
1. Systolic and diastolic BP a few hours before PMT
2. Systolic and diastolic BP at the beginning of PMT
3. Systolic and diastolic BP during PMT
4. Systolic and diastolic BP at the end the PMT
C) Use of anti-hypertensive medications on the day of PMT
D) Need for additional measures for blood pressure control at the time of the PMT
Conclusions
We have found in this cohort of patients that there is significant blood pressure variability related to AVF PMT procedure. In 17 out of 18 instances, the blood pressures were within the target range a few hours before the procedure, but at the start of the procedure, the mean SBP rose above the acceptable range.
The high BP at the start of, and during the procedure are likely to be due to anxiety and/or discomfort, but it could cause safety issues related to the procedure and could also predispose to acute cardiovascular events.
Administration of anxiolytics and/or parenteral anti-hypertensives (GTN, beta blockers) may help address this problem and may lead to fewer instances of the procedure being cancelled due to hypertension.