Natural Ischaemic Preconditioning Before First Myocardial Infarction

Natural Ischaemic Preconditioning Before First Myocardial Infarction: an Analysis of Prospectively Collected UK Electronic Primary Care Records Linked to the National Registry of Acute Coronary Syndromes

There is a sharp rise in the rate of coronary heart disease diagnoses and chest pain consultations in the 90 days before a first heart attack. There is some evidence that chest pain and angina symptoms in this period have a beneficial effect on heart attack outcomes in hospital and shortly after discharge. However, the available evidence is lacking in three key areas. First it is based on a retrospective patient report of symptoms after the heart attack has occurred; this means that patients are required to survive their heart attack and may make errors when reporting prior symptoms. Second, evidence for an effect on longer term outcomes, and coronary outcomes in particular (e.g. coronary death, further heart attacks) are unknown. Third, there is conflicting evidence that these effects might differ by age, in men and women, and according to treatment in hospital.

The investigators hope to address the limitations in the evidence by performing a large, prospective study of the occurrence, timing and effect of different types of symptoms and disease diagnoses occurring before heart attack.

The investigators hypothesise that prospectively collected, clinical measures of chest pain symptoms and cardiovascular diagnoses in primary care will have a beneficial effect on short term coronary mortality and may have a beneficial effect on longer term coronary outcomes.

Study Overview

• Status: Completed
• Conditions: Myocardial Infarction; Peripheral Arterial Disease; Angina Pectoris; Coronary Heart Disease; Cerebrovascular Disease

• Study Type: Observational
• Enrollment (Actual): 16000

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, WC1E 7HT
    • London School of Hygiene and Tropical Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

The study population is comprised of patients with a first myocardial infarction who are registered at those GPRD practices that agreed to the linkage with the MINAP database, and whose practices are "up to standard" according to GPRD criteria. Practices taking part in the GPRD are chosen to be representative of all UK practices, and 98% of people in the UK are registered with a GP. Therefore the GPRD should be a representative sample of the UK population.

Description

Inclusion Criteria:

• Patients in GPRD practices which are deemed "up to standard" by GPRD criteria will be included if their practice agreed to be linked to the MINAP, HES and ONS datasets.
• Patients must have at least one year of GPRD "up to standard" registration before the date of first MI.
• Age over 18.
• First myocardial infarction occurring between 1st January 2003 and 31st December 2008, as recorded in the Hospital Episode Statistics data or the Myocardial Ischaemia National Audit Project.

Exclusion Criteria:

• Patients will be excluded if they do not fulfil one of the inclusion criteria.

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort
MI without ischaemic preconditioning; Myocardial infarction unheralded by any previous cardiovascular disease diagnosis and without symptoms of chest pain in the previous 90 days.
MI with longstanding disease; Patients with myocardial infarction who have had diagnosed atherosclerotic disease for longer than 90 days preceding infarct.
MI with only chest pain; Patients with chest pain in the 90 days preceding MI, but with no prior atherosclerotic disease diagnoses.
MI with disease and chest pain; Myocardial infarction occurring with previously diagnosed atherosclerotic disease of longer than 90 days' duration, but with chest pain in 90 days preceding infarct.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recurrent myocardial infarction	Myocardial infarction occurring thirty or more days after the study start date.	Up to seven years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Coronary mortality	Coronary mortality, using ONS mortality statistics (ICD-10 codes I20-I25)	Up to seven years

Collaborators and Investigators

• Sponsor: London School of Hygiene and Tropical Medicine
• Collaborators: University College, London

Publications and helpful links

General Publications

• Herrett E, Bhaskaran K, Timmis A, Denaxas S, Hemingway H, Smeeth L. Association between clinical presentations before myocardial infarction and coronary mortality: a prospective population-based study using linked electronic records. Eur Heart J. 2014 Sep 14;35(35):2363-71. doi: 10.1093/eurheartj/ehu286. Epub 2014 Jul 19.

Study record dates

Study Major Dates

• Study Start: September 1, 2009
• Primary Completion (Actual): December 1, 2013
• Study Completion (Actual): December 1, 2013

Study Registration Dates

• First Submitted: May 21, 2012
• First Submitted That Met QC Criteria: May 22, 2012
• First Posted (Estimate): May 23, 2012

Study Record Updates

• Last Update Posted (Estimate): October 2, 2015
• Last Update Submitted That Met QC Criteria: October 1, 2015
• Last Verified: October 1, 2015

More Information

Terms related to this study

• Keywords: Myocardial infarction; Myocardial Ischaemia National Audit Project; General Practice Research Database; Hospital Episode Statistics; Ischaemic preconditioning; Office for National Statistics
• Additional Relevant MeSH Terms: Ischemia; Pathologic Processes; Necrosis; Myocardial Ischemia; Cardiovascular Diseases; Vascular Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Pain; Neurologic Manifestations; Atherosclerosis; Chest Pain; Myocardial Infarction; Infarction; Heart Diseases; Coronary Disease; Peripheral Arterial Disease; Peripheral Vascular Diseases; Angina Pectoris; Cerebrovascular Disorders
• Other Study ID Numbers: EH CALIBER IP; 086091/Z/08/Z (Other Grant/Funding Number: Wellcome Trust)