Strategies to be compared
CABG is a surgery using healthy artery or vein to graft healthy vessels to the blocked coronary artery to construct a new pathway for oxygen rich blood. It is inherently invasive, complex, and highly risky . [9,11] DES is a kind of PCI which is transported to diseased coronary arteries and open up the narrowed or blocked arteries, meanwhile is able to release the drug slowly to inhibit the cell proliferation so as to reduce the risk of restenosis. [26,27]
Markov Model Structure
This model consists of five mutally exclusive health states including event free, myocardial infarction (MI), stroke, repeat revascularization and death. MI, stroke and repeat ...view middle of the document...
Clinical Effectiveness Parameters
In this Markov model, FREEDOM trial, a two-arm RCT to compare the effectiveness of DES to CABG for diabetic patients with multi-vessel disease, was used as the input for the necessary parameters in the model.  We chose FREEDOM trial as the main source of effectiveness data for two reasons. First, this study enrolled participants close to the defined population in this model, mean age was 63.1 years old, and 83% had more than 3 diseased vessels. Second, this study reported high quality of information on the primary endpoint (composite of all-cause mortality, MI, and stroke), which included all the information needed for health states in this model. The outcome was observed annually and the 5-year outcomes were reported.
SYNTAX trial is a trial in complex coronary artery disease patients. This trial enrolled patients with de novo 3-vessel disease or left main artery disease while compared DES to CABG and reported the follow-up results of repeat revascularization patients, which also provided details for this model. However, the SYNTAX trial provided the follow-up results of repeat revascularization patients.
Table 1 shows the parameters inputed in this model. The transition proportions of mortality, proportion of repeat-revascularization, MI and stroke after first CABG or DES treatment (in the first cycle) were extracted from the 1-year outcomes reported in FREEDOM trial. The first year mortality was 4.1% in CABG group and 3.4% in DES group. Patients receiving CABG got benefit from lower risk of receiving repeat-revascularization and MI, but suffered from more strokes compared with the DESgroup: CABG VS DES: 4.4% VS 12.3%, 3.2% VS 5.7% and 1.8% VS 0.8% for repeat revascularization, MI, and stroke, respectively (See Table 1). These probabilities were calculated based on the observed numbers of events and the number of patients in the risk based on the original reports. However, in the original reports, more than one complications could occur concurrently, while in the model they were exclusive to each other. Thus the risks might be slightly different from the original reports.
For repeat revascularization patients, the transition probabilities were retrieved from SYNTAX trial. In this...