Stem cell treatment for acute myocardial infarction
Abstract
Background
Stem cell therapy offers a promising approach to the regeneration of damaged vascular and cardiac tissue after myocardial infarction (MI). This has resulted in multiple randomised controlled trials (RCTs) worldwide.
Objectives
To critically evaluate evidence from RCTs on the effectiveness of adult bone marrow‐derived stem cells (BMSC) to treat acute MI.
Search methods
MEDLINE (1950 to August 2007), EMBASE (1974 to August 2007), The Cochrane Library (Issue 3 2007), and CINAHL (1982 to August 2007) were searched. In addition LILACS, KOREAMED, INMED, Current Controlled Trials Register, the UK National Research Register and other handsearching was undertaken to August 2007.
Selection criteria
RCTs comparing autologous stem/progenitor cells with no autologous stem/progenitor cells in patients diagnosed with acute myocardial infarction (AMI) were eligible.
Data collection and analysis
Two reviewers independently screened all references, assessed trial quality and extracted data. Meta‐analyses using a random‐effects model were conducted and heterogeneity was explored using sub‐group analyses.
Main results
Thirteen RCTs (811 participants) were included. There were insufficient events on clinical outcomes like mortality to draw clear conclusions. Stem/progenitor cell treatment does not appear to be associated with an increase in adverse events but again the data do not allow clear conclusions. Left ventricular ejection fraction (LVEF) was the outcome with most results and there was marked heterogeneity between trials. There was however a consistent pattern indicating that BMSC treatment generally improves short‐term LVEF, with similar trends for left ventricular end systolic and end diastolic volumes (LVESV and LVEDV), infarct size or cardiac wall motion. There was a positive correlation between cell dose infused and the effect on LVEF measured by magentic resonance imaging.
Authors' conclusions
The results of this systematic review suggest that there is little evidence to assess the clinical effects of this treatment. Larger trials using optimal dosing and more reliable, patient‐centred outcomes are required. Several trials are ongoing but is unclear whether these will overcome the limitations of the current evidence base.
PICOs
Plain language summary
Stem cell treatment following a heart attack
Currently the standard treatment for people suffering a heart attack (due to a blockage in the artery supplying blood to the heart) is to directly open the artery with a tiny balloon in a procedure called primary angioplasty. The use of angioplasty and stents to reopen the blocked artery can lead to a 33% reduction in the mortality associated with this condition. Recently, bone marrow stem/progenitor cells have been tested to prevent the damage to heart muscle caused by a heart attack as an addition to angioplasty. Analysis of the first randomised controlled trials to 2007 indicates that this new treatment may lead to some improvements over conventional therapy as measured by surrogate tests of heart function. Further trials are however required to confirm that these changes translate into improvements in how patients function over the longer term and to confirm absence of side‐effects when the new treatment is used on a larger scale. Less than 1000 patients have so far been included in the 13 trials included in this systematic review.
