Friday, June 22, 2012
Singapore - A race against time when you suffer a stroke
I was driving home a fortnight ago when I was surprised by the sudden appearance of an ambulance driving away from the house. I then drove to the emergency department only to realise that my uncle had developed a massive stroke with confusion, inability to speak and complete loss of power on one side.
The ambulance team that arrived had acted with army-like precision and had whisked him off. He was rushed into the emergency department where a team of doctors swung into action with an efficiency that was marked by professionalism and well-practised clinical routines. Speed was of the essence and hence, he underwent computed tomography (CT) scan of the brain which confirmed that there was complete blockage of the main arteries on one side of the brain as a result of clots that had originated from the heart.
Not known to anyone previously, my uncle had developed atrial fibrillation, an irregular heart rhythm involving the upper chambers of the heart, causing the blood flow to slow down significantly. The blood flow in the left upper heart chamber had slowed down so significantly that blood clots had formed. The blood clots subsequently travelled from the heart to the brain arteries cutting off blood supply.
A remarkable outcome
The neurologist proposed giving intravenous recombinant tissue plasminogen activator (rtPA), a clot dissolving agent, but at the same time cautioned that there was also a risk of worsening of the stroke if the rtPA caused bleeding into the brain. If there was bleeding into the brain, the likelihood of a fatal outcome will be very high. Despite the risks, the decision was taken to proceed with the immediate administration of rtPA as the stroke was massive and was likely to be life-threatening.
I heaved a sigh of relief when an ultrasound Doppler scan (using sound waves to detect blood flow) of the blocked brain artery performed within an hour showed that flow had been restored. By next morning, my uncle could move his previously paralysed limbs and was able to respond verbally. Amazingly, he was discharged last Sunday with virtually full recovery.
Advances in medical science and highly trained medical professionals can make the difference between life and death. The administration of the clot dissolving drug within two hours of the onset of acute stroke had brought my uncle from the brink of death to full recovery. It was a remarkable achievement by the team of doctors who cared for him.
Dissolving clots in brain arteries
As early as 1996, the US Food and Drug Administration had approved intravenous recombinant tissue plasminogen activator (rtPA) as a treatment for acute stroke resulting from blockage of the brain arteries. Its approval was largely based on the National Institute of Neurological Disorders and Stroke (NINDS) rtPA stroke trial that showed treatment with intravenous rtPA within three hours of the onset of stroke symptoms led to an overall 32 per cent relative increase in the proportion of patients with minimal or no disability after three months.
However, rtPA was associated with 6 to 8.8 per cent risk of bleeding in the brain which was often fatal. The magic hour is "3" and the American Stroke Association/American Heart Association guidelines recommend that rtPA be administered within three hours for suitable patients with acute stroke.
Clearing clogged heart arteries
The benefits of administering clot-dissolving agents to dissolve blood clots in arteries has long been established for acute heart attacks since the 1980s. Since then, most patients with a sudden heart attack who are brought to the emergency department are given clot-dissolving agents.
At hospitals which have the resources, patients who are seen in the emergency department with a heart attack are sent to the heart department where teams of highly trained heart specialists work to open their heart arteries with "balloons" and stents (cylindrical metallic meshes used to open heart arteries) in the shortest time possible. These developments are embodied in the latest 2011 guidelines of the American College of Cardiology Foundation and American Heart Association which recommend that the blocked artery responsible for the acute heart attack be opened within 12 hours of a major heart attack.
Beating the clock
Treating sudden strokes and sudden heart attacks by teams of highly trained specialists in the shortest time possible has enabled many lives to be saved. The provision of such services means that significantly more manpower resources are required including getting specialist doctors and their teams to come in at any time of the night in the shortest time possible to do the best for their patients. The reality is that not all hospitals have these resources.
For those who are suspected to be in the throes of an acute heart attack or acute stroke, time is of the essence and they should get to the emergency department in the shortest time possible. However, sometimes getting there in time may not be enough.
This same fortnight, a patient related to me the unfortunate outcome of his relative who had developed sudden chest pain and had reached the emergency department by taxi. His relative walked in to register himself but had to wait in queue to see a doctor as the emergency department was extremely crowded and the staff was unable to differentiate between the severity of his case and others. Within 10 minutes of waiting, he collapsed and could not be revived as he suffered a massive heart attack. The autopsy showed severe blockage of all his three major heart arteries.
If you have reason to believe that one of your family members has an acute stroke or acute heart attack, calling the ambulance will not only ensure that the highly trained staff can attend to him quickly but their assessment will ensure that if he has a medical emergency, he will be immediately attended to upon his arrival in the hospital without any delay.
Dr Lim is medical director at the Singapore Heart, Stroke & Cancer Centre. He is also editor-in-chief, Heart Asia; British Medical Journals Publishing Group, chairman; Scientific Advisory Board, Asia Pacific Heart Association honorary professor and senior medical adviser, Peking University Heart Centre.
This series is brought to you by the Heart, Stroke and Cancer Centre. It is produced on alternate Saturdays.
Dr Michael Lim
The Business Times