Results
Table 1 demonstrates the clinical characteristics in the population before and after inverse probability weighting. Between August 2015 and December 2018, the baseline population had 265 patients undergo SLV and 394 underwent SAVR at our institution, the IPW weighted population had 258 patients undergo SLV and 394 undergo SAVR. In the baseline population, SLV patients had a greater mean age and were more likely to have had prior PCI (p<0.001), diabetes (p=0.01), a history of dialysis or creatinine >1.3 mg/dL (p=0.006), prior MI (p=0.008), or three-vessel disease (p<0.001). They were also more likely to have undergone a concomitant CABG with their SLV procedure (p<0.001). With these characteristics weighted after IPW, there were only significant differences found between SLV and SAVR regarding three characteristics; SLV patients were more likely to have prior PCI (p=0.01), prior CVA (p=0.05), and a history of three vessel disease (p=0.02).
Operative characteristics of the SLV and SAVR groups with IPW weighting are shown in Table 2. In the baseline population, SLV patients larger mean valve size (p<0.001), had more patients undergo minimally invasive approaches versus full sternotomy (p<0.001), shorter cross-clamp (p<0.001), on-pump (p<0.001), and total OR times (p=0.025).
There were few significant postoperative characteristic differences between the two groups, which are reflected in Table 3. The baseline population differed significantly only with SLV patients having a higher rate of rhythm disturbance requiring a permanent device permanent pacemaker or ICD (p=0.016), and longer median length of stay (p<0.001). The weighted population differed significantly in only one aspect; the SAVR group had a longer mean total ventilation time when compared to SLV (p=0.04). There was no difference in permanent pacemaker rate (10.7% in SLV vs 6.3% in SAVR, p=0.06). The pacemaker rate in the SLV group decreased over the study period from 14% to 4.2%. There was also no difference in length of stay.
Table 4 represents our cost analysis. In the crude analysis, hospital costs were higher for the SLV group, with a mean total cost of $71,600 (vs $61,100 in SAVR, p=0.018) and median total costs of $57,390 (vs $46,700 in SAVR, p<0.001). For isolated valve procedure, the mean cost was $43,650 for SLV and $38,914 in SAVR (p=0.003). For CABG with valve procedure, the SLV group had a mean cost of $61,487, while the SAVR group had a mean cost of $53,777 (p=0.07). The cost subcategories in which SLV had higher costs were room costs (p<0.001), pharmacy (p<0.001), total medical supplies (p<0.001) (including sterile supply and implant costs), ICU costs (p=0.002), radiology (p<0.001), respiratory (p<0.001), professional fees (p=0.005), and other costs (p=0.022). After IPW, there were no differences in median cost ($68,023 in SLV and $62,676 in SAVR; p=0.20).