Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis

CRD summary

This review compared survival rates in octogenarians following coronary artery bypass graft or percutaneous coronary intervention. The authors concluded that revascularisation could be successful in the short-term and long-term, but the quality of evidence was poor. This conclusion reflects the evidence presented, but its reliability is compromised by unconfirmed study quality, and methodological weaknesses in the review process.

Authors' objectives

To compare survival rates in octogenarians following coronary artery bypass graft or percutaneous coronary intervention.

Searching

EMBASE, MEDLINE and the Cochrane Library (with search dates ranging from 1950 to 2007) were searched to identify relevant English language articles. Search terms were reported. Reference lists were also scanned to locate further studies.

Study selection

Studies of coronary artery bypass graft or percutaneous coronary intervention involving patients aged 80 years or older, reporting survival outcomes at 30 days, were eligible for inclusion in the review. The primary outcomes of interest were in-hospital mortality (defined as the time from revascularisation to death from any cause within 30 days) and long-term survival. Studies of combined coronary artery bypass graft and valve operations, or studies where baseline clinical data or outcomes were not reported, were excluded.

Mean percentages relating to included patient characteristics were as follows: male participants 56%; non-elective procedures 55%; multivessel disease 64%, patients with diabetes 21%; patients with low left ventricular ejection fraction 37%. A significantly greater proportion of male patients, and those with multivessel disease, underwent coronary artery bypass graft than percutaneous coronary intervention.

Two reviewers selected the studies for inclusion in the review, and disagreements were resolved by consensus.

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

Data were extracted on 30 day outcomes, and (where possible) survival at one, three, and five years. Summary estimates were calculated, along with 95% confidence intervals (CI).

The authors did not state how many reviewers performed the data extraction. Mean procedure-specific values were imputed for missing clinical variables.

Methods of synthesis

Summary estimates were pooled in a random-effects meta-analysis (DerSimonian and Laird). Subgroup analyses were carried out, stratified by revascularisation type, using the following predictor variables: last year of patient enrolment into the individual study; gender; non-elective procedural status; multivessel disease; diabetes; and left ventricular ejection fraction. The impact of study methodology was also assessed (case series or registry data). Heterogeneity was assessed using the I² and X² statistics. Imputed data were used in a sensitivity analysis. Funnel plots were reported to be examined to assess publication bias.

Results of the review

Sixty-six studies (n=65,376 patients) were included in the review. All studies were treated as single-cohort studies. The authors reported that publication bias was a possibility in the analyses of long-term survival.

The pooled estimate of combined treatments for overall 30 day mortality was 6.3% (95% CI: 5.3 to 7.4); with one year survival rate at 86% (95% CI: 84 to 88), three year survival rate at 78% (95% CI: 74 to 81), and five year survival rate at 67% (95% CI: 61 to 72).

The pooled estimate of 30-day mortality for the coronary artery bypass graft (CABG) group was 7.2% (95% CI: 6.3 to 8.2) compared with 5.4% (95% CI: 4.4 to 6.4) for the percutaneous coronary intervention (PCI) group. One year survival for the CABG group was 86% (95% CI: 83 to 88) and 87% (95% CI: 84 to 91) for the PCI group. There were high levels of heterogeneity in these analyses (I² ranged from 77 to 86%). Three year survival for the coronary artery bypass graft group was 78% (95% CI: 74 to 82) and for the PCI group, 78% (95% CI: 68 to 87). Five year survival for the CABG group was 68% (95% CI: 62 to 73) and for the PCI group, 62% (95% CI: 46 to 77).

CABG, male gender, multivessel disease, and abnormal left ventricular ejection fraction were statistically significant predictors of 30 day mortality (p<0.001). CABG remained a significant predictor at one year (p=0.005). Recent treatment, non-elective status or revascularisation, and having diabetes, were statistically significant predictors of survival at 30 days (p<0.001). At one year, the date of treatment and diabetes status remained significant predictors (p ≤ 0.003). Sensitivity analysis confirmed these findings in all aspects except for non-elective revascularisation status, which became a non-significant predictor of mortality.

Authors' conclusions

Revascularisation could be successful in octogenarians in terms of short-term and long-term survival outcomes, but the quality of evidence was poor. Differential survival benefits from coronary artery bypass graft and percutaneous coronary intervention were undetermined due to variations in pre-procedural risk profiles.

CRD commentary

The review question was clear and this was supported by potentially reproducible inclusion criteria for all aspects apart from study design. The search strategy included some relevant sources, but the restriction to English language studies and no apparent search for unpublished material means that language and publication biases were a possibility. The latter was indicated in the authors own investigation of reporting bias. It was not clear to what extent the review process was protected against reviewer error and bias. Only the study selection process appeared to be conducted in duplicate, and it was not clear whether this was carried out independently. There was no reported assessment of study quality, but the authors overall judgement regarding poor quality of evidence is likely to be justified, given the reliance on observational studies. Study details were adequately provided, and the chosen method of meta-analysis was appropriate in the presence of heterogeneity. The authors' conclusion reflects the evidence presented, but its reliability is compromised by the unconfirmed quality of included studies, and by some methodological weaknesses in the review process.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that randomised controlled trials of high-risk octogenarians with balanced pre procedural risk are needed to investigate the effects of revascularisation on periprocedural and long-term outcomes. Future trials should also address medical intervention in addition to coronary artery bypass graft and percutaneous coronary intervention, and include quality of life as an outcome.

Funding

Not stated.

Bibliographic details

McKellar S H, Brown M L, Frye R L, Schaff H V, Sundt T M. Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis. Nature Clinical Practice Cardiovascular Medicine 2008; 5(11): 738-746. [PubMed: 18825133]

Original Paper URL

http://www.nature.com/nrcardio/journal/v5/n11/full/ncpcardio1348.html

Indexing Status

Subject indexing assigned by NLM

MeSH

Age Factors; Aged, 80 and over; Angioplasty, Balloon, Coronary /adverse effects /mortality; Coronary Artery Bypass /adverse effects /mortality; Coronary Disease /mortality /surgery /therapy; Female; Health Services for the Aged; Humans; Male; Patient Selection; Risk Assessment; Risk Factors; Time Factors; Treatment Outcome

AccessionNumber

12009104838

Database entry date

21/10/2009

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.