Table 2. Sensitivity Analyses of Payments to Cardiologists With Intravascular Microaxial LVAD Use in the Year of Payment and Year After Payment^a.

	% (No./total No.) performing any LVAD during index year	Any LVAD performed during index year, ARR (95% CI)b	% (No./total No.) performing ≥1 LVAD in year after index year	Any LVAD performed in year after index year, ARR (95% CI)c
Receipt of any LVAD payments
No	9.5 (1068/11 222)	1 [Reference]	11.5 (829/7179)	1 [Reference]
Yes	23.2 (1470/6336)	2.04 (1.89-2.20)	24.9 (991/3981)	1.90 (1.74-2.07)
Receipt of any LVAD payments among physicians not receiving payments in prior year
No	8.1 (448/5530)	1 [Reference]	9.6 (533/5530)	1 [Reference]
Yes	11.8 (195/1649)	1.26 (1.08-1.48)	18.0 (296/1649)	1.65 (1.45-1.89)
Receipt of LVAD payments by tertile of payment value, $
None	9.5 (1068/11 222)	1 [Reference]	11.5 (829/7179)	1 [Reference]
10.30-61.60	18.7 (391/2091)	1.73 (1.55-1.92)	19.2 (273/1420)	1.51 (1.33-1.71)
61.70-182.00	18.4 (397/2155)	1.69 (1.52-1.87)	23.8 (303/1273)	1.87 (1.66-2.10)
182.10-99 045.10	32.6 (682/2090)	2.68 (2.45-2.93)	32.2 (415/1288)	2.33 (2.09-2.59)

Abbreviations: ARR, adjusted risk ratio; IABP, intra-aortic balloon pump; LVAD, intravascular microaxial left ventricular assist device.

^a Risk ratios are adjusted for physician sex, postgraduate year (categorized as <10, 10-20, and >20 years in training, as well as missing), census region, volume of percutaneous coronary interventions per year (categorized in quartiles), study year (2016, 2017, or 2018), placement of any IABPs, and payments from IABP manufacturers. Index year refers to the year of payment.

^b Denominator is 17 558 cardiologist-years, constructed from 6398 cardiologists meeting inclusion criteria (most cardiologists were included in multiple years).

^c Denominator is 11 160 cardiologist-years, constructed from 5974 cardiologists with 2 contiguous years of claims data.