Some patients needing medical treatment under Betsi Cadwaladr University Health Board will be sent to Liverpool to receive care instead.
The north Wales health board said "a very small number of complex vascular cases" will be sent to England over the next four weeks.
It pointed to current "staffing capacity issues" as being the reason why some cases would need to be redirected, but added that they are looking to hire additional staff.
It comes as a damning report into vascular services at BCUHB found patients experienced substandard care – including one at Ysbyty Glan Clwyd in Denbighshire who received an unnecessary amputation.
In a statement released on Wednesday (March 16), Dr Nick Lyons, Executive Medical Director at Betsi Cadwaladr University Health Board (BCUHB) said they were implementing the recommendations from that report, including "working in closer collaboration with the Liverpool vascular network".
BCUHB said it expects the change will mean around four additional emergency procedures taking place at Liverpool University Hospitals NHS Trust, rather than at Ysbyty Glan Clwyd.
However it also added that some routine surgeries would be delayed.
The statement reads: "The majority of vascular service activity such as routine surgery, diagnostic procedures and outpatient appointments will continue in north Wales as usual.
"This means that most patients will continue to receive their vascular surgery at Ysbyty Glan Clwyd, though we expect a further five patients per week over the same four week period to have their surgery delayed.
"Additionally, some 12 outpatient appointments per week (around 50 during this four week period) will be postponed."
Patients will be contacted to discuss their treatment and a helpline has been set up by the health board to offer support to vascular patients. The telephone number is 03000 851389 and is open 9am to 5pm Monday to Friday, except Bank Holidays.
What did the Royal College of Surgeons report find?
The move follows a report from the Royal College of Surgeons (RCS), which found serious deficiencies in care after reviewing the records of 44 patients under BCUHB's vascular services.
Issues with documentation, record-keeping, consent-taking and communication between clinicians were highlighted. The report also described a "loss of dignity" for some patients.
Some specific examples included an amputee “needing to be carried to the toilet” by his wife after being discharged without a care plan and a patient being given an “unnecessary and futile” amputation.
While good practice was noted in some areas, nine recommendations were made, including five urgent ones “to address patient safety risks”.
The service has now been categorised by Health Inspectorate Wales as a "Service Requiring Significant Improvement".
Following the announcement that some vascular patients would be seen in England rather than under BCUHB, Dr Nick Lyons, an executive at the health board, said: "We are implementing the recommendations of the recent Royal College of Surgeons reports on our vascular service. These include working in closer collaboration with the Liverpool vascular network on complex vascular cases.
"During the next few weeks, we expect to be strengthening the capacity and capability of the existing vascular team further. We are also temporarily adding more consultants onto our on-call rota to ensure the safety of our patients.
"We are being open and transparent about the challenges in this service. It is the only way we can build trust and confidence with the public we serve."
He also apologised for delays to treatment of vascular patients and said patient safety is their priority, which is why this "temporary solution" had been agreed.
In the statement announcing that some vascular patients would be seen in England rather than under BCUHB, the health board said there has recently been "two concerning safety incidents in the vascular service" which they are investigation.
Responding to this, Rhun ap Iorwerth MS, Plaid Cymru Spokesman for Health and Care said: “Another week, another alarm is raised about vascular services in the north of Wales.
"Now we’re told that there have been ‘two concerning safety incidents’. Whilst respecting patient confidentiality, we need total transparency from BCUHB about the circumstances.
"But we also need to see Vascular Services in the north being put in the highest possible level of special measures as work begins to restore patient confidence and to restore the quality of local services.”
A Welsh Government spokesperson said: “We are very concerned about these recent incidents and the Health Minister has been clear that the health board needs to address these service issues with immediate effect.
"It is encouraging support is being offered by the Liverpool vascular network and this comes in response to the recommendations made by the Royal College of Surgeons.”