Mortality
In-hospital mortality figures were given for 10 out of the 11 comparative studies found2,15,20,44-51. None stated a significant difference in mortality rates between Witnesses and non-Witnesses. Witness in-hospital mortality rate in the comparative studies varied between 0 and 18.8%. These figures are similar to those found in non-comparative studies, which ranged from 0 to 14.3%8,16,29,43,52,53,57. One study by Ramiaramananaet al 53. split the 153 Witness study population into low and high risk patients using their co-morbidities. Of the 13 classed as high risk, 3 died (23%), which was significantly higher than those in the low risk group (3 of 140 (2.1%), p=0.001)53. Jassar et al. 52compared mortality rates in Witnesses undergoing elective versus urgent surgery, showing the mortality rate was higher in the elective surgery group (5 vs 0, respectively), although the difference was not significant (p=1.0). This study suggests urgent surgery can be carried out on Witnesses with low risk, despite no preoptimization of Hb levels.
30 day mortality was reported in a number of studies. Only three of the 11 comparative studies reported the data, but of the three studies, no difference in rates was found44,46,49. Again, non-comparative studies found similar results (comparative: 0 to 3.06%44,46,49; non-comparative 0 to 5%4,16,43,57). Vaislic et al. reported a drop in 30 day mortality with time, stating 3% in those operated on between 1991-2003 and 1% for those between 2003-201216. They account for this by better techniques and optimisation preoperatively. A study by Ott and Cooley in 1977 found a 30 day mortality rate of 9.4%61, but this study was more than 40 years ago and also did not distinguish between outcomes for adults and children, which may account for the higher percentage seen.
Longer term survival rates were reported in few studies, with only one of the comparative studies sharing this outcome. Pattakos et al.reported survival estimates of Witnesses were 86%, 69%, 51%, and 34% at 5, 10, 15, and 20 years after surgery, respectively, vs 74%, 53%, 35%, and 23% for non-Witnesses, showing Witnesses had better survival rates15. Jassar et al. stated the 1 and 5 year survival rates for Witnesses after cardiac surgery to be 87.3%±3.4 and 76.1%±5.4, respectively52. The 5 year survival rates reported for those undergoing CABG only were reported to be 90.3%.