Influence of hospital volume and outcomes of adult structural heart procedures

Table 1 Multivariate regression for different outcomes during transcatheter aortic valve repair

	Multivariate simple logistic regression for mortality		Multivariate simple logistic regression for any complications and mortality		Multivariate simple logistic regression for LOS (LOS ≥ 6 d)		Multivariate simple logistic regression for disposition of transfer to short-term hospital/other facilities/home health care
Variable	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
Hospital volume quartile
1st quartile	1	Referent	1	Referent	1	Referent	1	Referent
2nd quartile	0.92 (0.70-1.21)	0.550	0.86 (0.76-0.99)	0.029	0.82 (0.71-0.94)	0.004	1.06 (0.91-1.23)	0.451
3rd quartile	0.80 (0.60-1.06)	0.114	0.70 (0.61-0.80)	< 0.001	0.91 (0.80-1.05)	0.194	0.65 (0.56-0.75)	< 0.001
4th quartile	0.38 (0.27-0.54)	< 0.001	0.71 (0.62-0.82)	< 0.001	0.85 (0.74-0.98)	0.024	0.77 (0.66-0.90)	0.001
Access
Transfemoral	1	Referent	1	Referent	1	Referent	1	Referent
Trans-apical	1.54 (1.17-2.03)	0.002	1.44 (1.26-1.64)	< 0.001	2.27 (1.96-2.63)	< 0.001	1.37 (1.18-1.60)	< 0.001
Age (10-yr increment)	1.26 (1.07-1.47)	0.005	0.97 (0.91-1.03)	0.316	1.07 (1.00-1.14)	0.051	1.57 (1.46-1.69)	< 0.001
Gender
Male	1	Referent	1	Referent	1	Referent	1	Referent
Female	1.09 (0.89-1.36)	0.392	1.21 (1.11-1.33)	< 0.001	1.43 (1.30-1.57)	< 0.001	1.99 (1.79-2.21)	< 0.001
Charlson score
0	1	Referent	1	Referent	1	Referent	1	Referent
1	1.29 (0.78-2.14)	0.321	1.13 (0.92-1.38)	0.236	1.23 (1.01-1.50)	0.038	1.40 (1.14-1.72)	0.002
≥ 2	1.60 (1.01-2.55)	0.047	1.73 (1.44-2.08)	< 0.001	2.02 (1.69-2.42)	< 0.001	1.72 (1.42-2.07)	< 0.001
Bed size of hospital
Small	1	Referent	1	Referent	1	Referent	1	Referent
Medium	0.43 (0.28-0.67)	< 0.001	0.89 (0.70-1.15)	0.386	1.18 (0.91-1.52)	0.215	1.17 (0.88-1.56)	0.279
Large	0.42 (0.29-0.61)	< 0.001	0.73 (0.58-0.91)	0.005	1.36 (1.09-1.71)	0.007	1.23 (0.96-1.58)	0.103
Model 2
Hospital volume quartile (5 procedures increment)	0.88 (0.83-0.93)	< 0.001	0.94 (0.92-0.95)	< 0.001	0.93 (0.91-0.95)	< 0.001	0.95 (0.94-0.97)	< 0.001
Model 3
Hospital volume quartile (10 procedures increment)	0.77 (0.69-0.86)	< 0.001	0.87 (0.84-0.91)	< 0.001	0.87 (0.84-0.90)	< 0.001	0.91 (0.87-0.95)	< 0.001

LOS: Length of stay; OR: Odds ratio.

Table 2 Multivariate predictors of primary and secondary outcomes for patients who underwent transcatheter mitral valve repair

Variable	OR (95%CI)	P value
Hospital volume tertile
1st tertile	1	Referent
2nd tertile	0.23 (0.12-0.41)	0.177
3rd tertile	0.12 (0.06-0.23)	< 0.001

OR: Odds ratio.

Table 3 Hospital volume and primary outcome, length of hospital stay > 2 d, and predictor of highest quartile of cost of care (> $17160) following atrial septal defect/patent foramen ovale closure: Multivariate adjusted model

	Primary outcome		Length of stay		Cost of care
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
Hospital volume (n of procedure per yr)
1st tertile (< 14)	Referent		Referent		Referent
2nd tertile (14-37)	0.73 (0.57-0.93)	0.013	0.50 (0.36-0.69)	< 0.001	0.72 (0.49-1.07)	0.104
3rd tertile (> 37)	0.67 (0.48-0.94)	0.019	0.37 (0.24-0.57)	< 0.001	2.55 (1.54-4.20)	< 0.001

Three levels hierarchical mixed effects models were generated (patient level factors nested within hospital level factors) with the unique hospital identification number incorporated as random effects. Primary outcome (n = 6328) was adjusted for age, sex, Deyo’s modification of Charlson Comorbidity Index, Median Household income, primary payer, hospital teaching status, emergent/urgent admission, weekend admission, Intracardiac Echocardiography use during procedure and hospital volume. In length of stay > 2 d (n = 6302) and predictors of highest quartile of cost (> 17160 $) (n = 5389), we included all variables in primary outcome. Hospital volume were calculated based on the unique hospital identification number on year to year basis. OR: Odds ratio.

Table 4 Multivariate regression for different outcomes left atrial appendage closure

Any procedural complication or death (n = 264)	OR with 95%CI	P value
Hospital annual LAA closure volume (per unit increase)	0.89 (0.85-0.94)	< 0.001
Length of stay (n = 258)	HR	P value
Hospital annual LAA closure volume (per unit increase)	0.95 (0.92-0.98)	< 0.001
Cost of hospitalization (n = 250)	Estimate ($)	P value
Hospital annual LAA closure volume (per unit increase)	0.96 (0.93-0.98)	< 0.001

LAA: Left atrial appendage; OR: Odds ratio.