Hospitals fail to deliver therapy for busting clots within the recommended time.

The number of stroke victims to get clot-busting injections has grown greatly, but treatment times remain well outside the recommended "golden hour" for reducing the risk of disability, a study has found.

Clot-busting therapy, called thrombolysis, is an intravenous medicine that can be given within several hours to many victims of stroke caused by a clot blocking an artery in the brain. These account for 80-85 per cent of the 9000 strokes that occur each year in New Zealand.

Around 15 per cent of stroke survivors are so badly disabled they have to live permanently in a hospital or rest home.

The study, based on a national register in the first half of last year, found that 6.4 per cent of patients suffering a clot-based stroke were given the medicine called alteplase to break down the clot. An audit in 2009 had found only 3 per cent were treated with clot-busting therapy, according to Dr Anna Ranta and colleagues, writing in today's NZ Medical Journal.


But in the 2015 data, only 30 per cent of patients receiving clot-busting therapy got it within an hour of arrival to hospital.

"Earlier treatment is associated with better outcomes," the researchers say, "and every 15-minute acceleration in the start of treatment can result in a 4 per cent greater odds of walking independently on discharge."

A person arriving at hospital after hours would have faced a median wait of 82 minutes, "door to needle", to start the intravenous treatment - 13 minutes longer than the 69-minute wait during business hours.

The national all-hours median was 74.5 minutes, but times varied by region, from 69 minutes in the South Island, to 82 in Auckland-Northland. Larger district health boards may have been quicker than smaller ones and the hospitals with higher-tech "tertiary" services for stroke care - Auckland City, Waikato, Wellington, Christchurch and Dunedin - were faster, with a median of 67.5 minutes, than non-tertiary hospitals, on 81 minutes. The national median time from stroke onset to arrival at hospital was 72 minutes.

The researchers say the thrombolysis therapy rate of 6.4 per cent of patients meets the Health Ministry target of 6 per cent.

"This is similar to the national thrombolysis rate of 7 per cent in Australia (2012), but lower than 9.1 per cent in England (2011)."

Ranta indicated to the Herald specialists will support an increase to 8 per cent by 2018.

Stroke Foundation acting chief Don Scandrett said thrombolysis could be the difference between life and death, or between a positive recovery and permanent disability.

This was why the foundation had spearheaded the "FAST" campaign on recognising a stroke and calling 111.


Average time in minutes from arrival at hospital to start of clot-busting therapy

• 82 - Auckland-Northland

• 69.5 - Mid-North Island

• 74 - Lower North Island

• 69 - South Island

• 74.5 - All New Zealand

• 60 - Ideally the maximum

Source: NZ Medical Journal