Medical research
“The Survival Rate of Out-of-hospital Cardiac Arrest (OHCA)” (15 Jun 2022)
Press Release (For Immediate Release)
Hong Kong's first 3-year case-based study on "The Survival Rate of Out-of-hospital Cardiac Arrest"
- The survival rate of young patient is almost of 10 folds higher with timely in use of AED
-8 potential strategies to Increase Survival
(Hong Kong, 15th Jun 2022) Out-of-hospital cardiac arrest
(OHCA) is the major cause of unexpected and sudden death. If patients with
sudden OHCA are delayed in Cardiopulmonary Resuscitation (CPR) or public-access
defibrillation (PAD)1,
their survival rate will drop by 7-10% for every minute of delay. To
investigate the prevalence and survival rate of OHCA in Hong Kong, SADS HK
Foundation (SADS HK) commissioned a research team at the Department of
Rehabilitation Sciences of The Hong Kong Polytechnic University (PolyU) to
conduct the first large scale study using three-year medical cases’ data of
“The Survival Rate of Out-of-hospital Cardiac Arrest (OHCA)” in Hong Kong. The
main objective of this study is to investigate the prevalence and survival rate
of young patients <=age 40 with OHCA in Hong Kong, and to find out the
factors that could increase the survival rate of this targeted group.
Low OHCA Survival in Hong
Kong
The team gathered 22,014 OHCA cases between
December 2017 and December 2020, of which 21,617 individuals didn’t survive to
discharge. For the OHCA patients <=age 40, a total of 829 cases were
identified, only 35 (4.2%) cases survived to discharge. From these 829
patients, only 34% and 6.8% had ever received CPR and AED respectively.
1.5 OHCA cases found every
2 days in Hong Kong’s young individuals
Dr
Richard XU, Co-Principal Investigator of the study and Research Assistant
Professor of the Department of Rehabilitation Sciences at PolyU, explained,
“Previous studies on OHCA focus on the overall prevalence and survival rate,
which offer limited insights about young patients. This finding is the first of
its kind that focuses on Hong Kong OHCA young patients of ages 40 or below.”
The study found that between December 2017 and December 2020, there were on
average 1.5 OHCA incidents every 2 days that involved young patients in Hong
Kong.
10 folds improvement in survival rate with
timely use of AED
Prof. Amy FU, the other Co-Principal
Investigator who is also Peter Hung Professor in Pain Management and Associate
Head of the Department of Rehabilitation Sciences at PolyU, said, “Our study
shows survival to hospital was largely improved from around 15% to 24.8% and
44.6% when cardiopulmonary resuscitation (CPR) or Automated External
Defibrillator (AED) were applied respectively; the survival to discharge from
hospital was largely improved from about 2% to 9.2 % and 25% when CPR or AED
were delivered at the incident site respectively. Such findings suggested that
the survival rate for OHCA young patients is enhanced by nearly 10 times if
they can receive AED on-time.”
She added that overall, only 17.7 % of the
young people who were attacked by cardiac arrest could survive to arrive at
hospital and 4.2% could leave hospital. Meanwhile, the male to female young
patients ratio was 2 to 1.
8 potential strategies to Increase Survival
Rate
Dr Siu Yuet-chung, Axel, Specialist in
Emergency Medicine and Advisory Member of SADS HK, revealed that “When compared
to other developed Asian countries/regions, the survival rate of Hong Kong OHCA
individual is extremely low (1.8%). And there is an acute shortage of Automated
External Defibrillator (AED) in Hong Kong and the number of AED in Hong Kong is
about 120 times fewer than Japan (5,000 vs.610,000). The study proved that the
CPR and AED absolutely increased 10 times of the rate of survival in young
patients. Otherwise, the survival rate drops by 7-10% in every minute based on
overseas experience.” Dr. Siu emphasizes “The public need to understand the
importance of first aid, publicize the use of CPR or AED is needed.”
To increase the rate of survival, Dr. Siu
urges to have 8 strategies. Firstly, public education that enables a better
understanding on the cardiac warning signs to reduce OHCA. Secondly, CPR and
AED must be added as mandatory curriculum in school in order to enhance the knowledge
of first aid in our young generation. Thirdly, the government must consider the
enactment of Samaritan’s Law to alleviate public concerns about administering
first aid. Fourthly, all public places and private/public properties should be
equipped with AEDs and our government should consider to offer subsidy to
enhance the AED allocation ratio per capita. Fifthly, unified the logo of AED
to facilitate the easier identification of the AED installment site. Sixthly,
enhance the “AED Anywhere for Anyone” by Fire Services Department as a
blueprint to further develop an AED location mobile apps to browse the AED
location for quick response. Seventhly, the government should promote the AED
registration of all AED in anywhere that can be accessible by public.
Finally, the government should also establish
an OHCA database to centralize the integration of all OHCA data including the
cases, demographic, locations, rate of survival, etc..
Patient sharing - Experienced the importance
of First Aid
Tommy Fung, a patient of OHCA, shared his
experience, “When it happened in the early morning, I suddenly lost
consciousness. My wife told me that I was stiff and stopped breathing for a
while. I was so fortunate that paramedics kept talking with my wife when they
were on the way to my home and instructed her how to perform CPR even she had
no experience at all. When they arrived, AED was applied immediately. I had
been without spontaneous breathing for more than 20 minutes by the time I
arrived at the hospital.” He hopes that the public will not underestimate the
importance of first aid. Timely implementation of first aid could save the
lives of people at home or around them.
SADS HK urges pay more attention to the
warning signs of cardiac
OHCA could have many causes, it could lead to
sudden death of an apparently healthy undiagnosed young person. Sudden
Arrhythmia Death Syndromes (SADS) is one of the many causes. Prevention is
better than cure. To prevent cardiac arrest due to SADS, SADS launched the
subsidy scheme to support the SADS victim’s or family member for their first
clinical consultation. SADS HK urges the public to pay more attention to the
warning signs of cardiac and to understand family medical history. If anyone
experience any warning signs, please seek the cardiologist’s medical advice as
soon as possible to avoid OHCA accidents.
SADS HK medical research (2014-2015)
SADS HK medical research report was published in "Hong Kong Medical Journal" in January 2019
Sudden Arrhythmia Death Syndromes (SADS) in Young Victims of Sudden Cardiac Death in Hong Kong Identified by Clinical or Molecular Autopsy of Victims and Clinical Evaluation of Their First Degree Relatives
Brief Reult of SADS-HK Study (Oct 2017)
Under the two-year research project, young cardiac death victims with uncertain causes of death or inheritable cardiomyopathy examined at public mortuaries were chosen for molecular autopsies, while their first-degree relatives were referred for clinical assessment and/or genetic screening. Findings revealed that nearly 30% of the 21 sudden cardiac death victims carried SADS-related genetic variants. Approximately a quarter of sudden cardiac cases saw their victims died in sleep and three of them had a family history of sudden deaths. Around 30% of SADS victims experienced fainting for uncertain reasons when alive but failed to seek medical treatment or actively followed up on their conditions. Dr. Mok Ngai-shing, Specialist in Cardiology and Consultant of Princess Margaret Hospital, who oversees this project, said: “A family history of sudden deaths and fainting for uncertain reasons are vital clues to SADS and those with the conditions should seek early medical intervention to avoid missing the golden hour for diagnosis and treatment.”
According to the study, more than 50% of first-degree relatives subjected to genetic screening were found to carry SADS-related genetic variants , requiring follow-up medical care and preventive therapies. Dr. Chloe Mak, Specialist in Chemical Pathology and Consultant of Princess Margaret Hospital, who is responsible for the genetic screening administered in this project, said: “In this study, there are families with a strong family history of two to three sudden death victims with unknown causes. This causes the surviving family members great distress. This study not only partially confirms the causes of death among the sudden death victims but also facilitates their relatives with the dormant SADS disease to receive early preventive treatment based on their conditions, in order to reduce their risk exposure to sudden death.” Next-generation sequencing (NGS) was applied in the investigation into the victims’ causes of death, which yielded important genetic data and valuable experiences for the first time in local SADS research. The study is considered a major leap forward in genetic studies conducted in Hong Kong and also has established the foundation of a feasibility model on incorporating molecular autopsy in forensic investigation, next-generation sequencing analysis in hereditary cardiac disorders, genetic counseling, clinical assessment and referral.
PROTOCOL SYNOPSIS
Written by Dr. Ngai-Shing MOK,
Coordinating Principal Investigator,
Princess Margaret Hospital,Hong Kong
-2014-
Introduction
Sudden Cardiac Death (SCD) is one of the most common causes of death and a major and tragic complication of a number of cardiovascular diseases. The death is most often unexpected and has major implications for the surviving family and the community. SCD is defined as a death occurring usually within an hour of the onset of symptoms, due to an underlying cardiac disease. Whereas SCD in the older populations is most frequently due to underlying coronary artery disease and heart failure, SCD in young people (aged < 40 years) is commonly caused by genetic diseases such as inherited arrhythmogenic cardiomyopathies including hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC), and cardiac ion channel diseases including Brugada syndrome (BrS), congenital long QT syndrome (LQTS), short QT syndrome (SQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT). They are collectively known as Sudden Arrhythmia Death Syndromes (SADS). While autopsy may reveal the underlying cardiac diseases in young SCD victims, up to 30% of the autopsy fails to identify a cause of death and those SCD victims are referred to as suffering from Sudden Unexplained Death (SUD). Recently we conducted a retrosepective 5-year review of autopsies done in local young SCD vicitms aged 5-40 years and found 25% of them suffered from SUD. It is believed that a significant proportion of SUD is caused by SADS.
As SADS are genetic diseases, two different approaches to identify SADS among young SUD victims have been used. The first approach involves detailed clinical and targeted genetic examination of the surviving relatives of SUD victims. Studies using this approach suggested that SADS may account for approximately 40% of autopsy-negative SUD in young people. However, this approach may not be able to identify subjects with concealed form of SADS due to incomplete penetrance and variable expressivity of the pathological mutations. The second approach is to perform molecular autopsy on SUD victims which involves post-mortem genetic testing for SADS. The landmark study on molecular autopsy by Mayo Clinic showed over one-third of SUD cases hosted a presumably pathogenic mutations of cardiac ion channel diseases. Thus a combined approach using both cardiac evaluation of surviving relatives and molecular autopsy on SUD victims should theoretically give a higher yield on elucidating the underlying causes of SUD. Identification of the underlying cause of SCD has at least two major clinical implications. First, the identification of a cause of death has a major influence in families in coming to terms as to why their child or spouse died suddenly. The diagnosis brings some level of closure in this respect. Second, the identification of a genetic cause of SCD provides the family with a diagnostic test for screening other at-risk family members, in conjunction with clinical screening approach and allows for an early initiation of therapeutic and preventive strategies in affected family members with the ultimate goal to reduce sudden death.
To date, there is scarce local data on the prevalence and types of SADS underlying SCD or SUD in young people. There is little local experience of performing molecular autopsy for SUD victims in Hong Kong. Molecular autopsy is not included as part of medico-legal investigation of underlying cause of SUD by forensic pathologists or within HA hospitals. We recently identified Brugada syndrome in a young SUD victim in Princess Margaret Hospital through molecular autopsy and clinical and genetic evaluation of his first-degree relatives. The present study is first of its kind in Hong Kong and it will provide important data on the prevalence and types of SADS among young SCD victims in local population.
Protocol Synopics
Protocol Title: Sudden Arrhythmia Death Syndromes in Young Victims of Sudden Cardiac Death in Hong Kong Identified by Clinical or Molecular Autopsy of Victims and Clinical Evaluation of Their First Degree Relatives
Study Location: Hong Kong
No. of Study Sites: 1
Study Design:
This is a prospective study. Young sudden cardiac death (SCD) victims (age 5-40 years old) will be identified and recruited into study by forensic pathologists after finding of either an inheritable arrhythmogenic cardiomyopathy or no structural heart disease on autopsy and a negative toxicology screening. Their first-degree relatives will be referred by forensic pathologists to study centre for genetic counseling and recruitment into the study
Primary Objective: To determine the prevalence and types of Sudden Arrhythmia Death Syndromes (SADS) as the underlying causes of SCD among local young victims through clinical and molecular autopsy of SCD victims and clinical and genetic evaluation of their first degree relatives
Secondary Objectives:
- To study the genetic basis of SADS among young SCD victims in Hong Kong
- To study the diagnostic yields of various approaches in identifying SADS in sudden unexplained death (SUD) families using (A) molecular autopsy in young SUD victims using the next generation sequencing techniques; (B) clinical evaluation of the first-degree relatives of young SUD victims, and (C) combining molecular autopsy in young SUD victims and clinical and targeted genetic evaluation of their first-degree relatives
No. of Subjects: 40 SCD victims and approximately 160 first degree relatives
Recruitment Period: 2 years
Follow-up Period: up to 6 months
Follow-up: Follow-up clinic visits at 3 months and if indicated at 6 months
Primary Endpoint:
Prevalence and types of SADS among the young SCD families in the study population identified by clinical and molecular autopsy of SCD victims and/ clinical and targeted genetic evaluation of their first-degree relatives
Secondary Endpoints:
- Genotypes of SADS victims in the study population
- Number of young SUD families identified with SADS by molecular autopsy
- Number of young SUD families identified with SADS by clinical evaluation of first-degree relatives
- Number of young SUD families identified with SADS by a combined approach
- Pattern of inheritance of SADS and their clinical and genetic characteristics among young SUD families
International Medical Research
Other International Medical Research and Articles on SADS/ Sudden Cardiac Death:
