Infarct Volume Predicts Hospitalization Costs in Anterior Circulation Large-Vessel Occlusion Stroke

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Fig 1.
Study flow diagram. Endovascular stroke data base July 2014 to October 2014: three hundred twenty-four total stroke interventions (66 posterior circulation, 88 at an affiliated hospital without cost-tracking) with 173 patients eligible for anterior circulation large-vessel occlusion.
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Fig 2.
Univariate analysis: cost versus final infarct volume.

Table 1:

Baseline patient demographics^{^a}

	All Patients (n = 341)	Endovascular Therapy (n = 133)	IV tPA-Only (n = 61)	No Reperfusion Therapy (n = 147)
Cost (median) (IQR)	$16,446	$21,871	$14,456	$13,401
	($9823–$27,165)	($15,672–$31,363)	($7626–$19,701)	($8308–$23,589)
Age (median) (IQR)	69 (57–80)	68 (58–80)	75 (59–83)	66 (55–79)
Female	165 (48.4%)	65 (48.9%)	33 (54.1%)	67 (45.6%)
A. Fib	162 (47.5%)	65 (48.9%)	37 (60.7%)	60 (40.9%)
Alcohol abuse	27 (7.9%)	7 (5.3%)	4 (6.6%)	16 (10.9%)
Anticoagulation	29 (8.5%)	11 (8.3%)	5 (8.2%)	13 (8.8%)
CAD	78 (23.0%)	26 (19.6%)	19 (31.7%)	33 (22.6%)
CAS	72 (21.1%)	23 (17.3%)	10 (16.4%)	39 (26.5%)
CHF	59 (17.5%)	15 (11.4%)	17 (28.3%)	27 (18.5%)
CKD	19 (5.6%)	3 (2.3%)	4 (6.7%)	12 (8.2%)
Dementia	15 (4.4%)	2 (1.5%)	7 (11.7%)	6 (4.1%)
Dissection	17 (5.0%)	9 (6.8%)	2 (3.3%)	6 (4.1%)
DMII	103 (30.2%)	51 (38.3%)	25 (41.0%)	27 (18.4%)
Hyperlipidemia	149 (43.7%)	64 (48.1%)	29 (47.5%)	56 (38.1%)
Hypertension	291 (85.3%)	111 (83.5%)	55 (90.2%)	125 (85.0%)
Illicit drug use	8 (2.3%)	0 (0.0%)	0 (0.0%)	8 (5.5%)
Obesity	44 (12.9%)	12 (9.0%)	19 (31.1%)	13 (8.8%)
OSA	31 (9.2%)	12 (9.0%)	8 (13.1%)	11 (7.5%)
Psychiatric	33 (9.7%)	9 (6.8%)	7 (11.5%)	17 (11.6%)
Tobacco	124 (36.6%)	40 (30.1%)	21 (34.4%)	63 (42.9%)

Note:—A. Fib indicates atrial fibrillation; CAD, coronary artery disease; Dissection, ipsilateral carotid dissection; CAS, ipsilateral carotid artery stenosis; CHF, congestive heart failure; CKD, chronic kidney disease; DMII, diabetes mellitus II; OSA, obstructive sleep apnea; Psychiatric, any psychiatric comorbidity.
↵a Values represent total number and percentage unless otherwise indicated.

Table 2:

Stroke characteristics^{^a}

	All Patients (n = 341)	Endovascular Therapy (n = 133)	IV tPA-Only (n = 61)	No Reperfusion Therapy (n = 147)
Baseline NIHSS (median) (IQR)	16 (13–21)	16 (13–19)	16 (12–22)	17 (13–21)
FIV (mL) (median) (IQR)	59.9 (17.1–129)	27 (9.4–86.0)	62.5 (8.7–118.7)	93 (37.8–170.0)
Left hemisphere	175 (51.3%)	65 (48.9%)	38 (62.3%)	72 (48.9%)
Level of occlusion
Extracranial ICA	7 (2.0%)	2 (1.5%)	4 (6.6%)	1 (0.6%)
Tandem occlusion	39 (11.4%)	31 (23.3%)	2 (3.3%)	6 (4.1%)
Intracranial ICA	79 (23.2%)	16 (12.0%)	9 (14.8%)	54 (36.7%)
M1 division of MCA	166 (48.7%)	74 (55.6%)	33 (54.1%)	59 (40.1%)
M2 division of MCA	50 (14.7%)	10 (7.5%)	13 (21.3%)	27 (18.4%)
PH1	14 (4.1%)	3 (2.3%)	8 (13.1%)	4 (2.7%)
PH2	9 (2.6%)	5 (3.8%)	3 (4.9%)	1 (0.7%)
ASPECTS (median) (IQR)	Data unavailable	8 (7–9)	Data unavailable	Data unavailable
Wake-up stroke	Data unavailable	19 (14.3%)	Data unavailable	Data unavailable
Onset to treatment (min) (median) (IQR)		310 (236–465)	138 (115–155)
IA intubation		5 (3.7%)
Recanalization (mTICI)
mTICI 0		1 (0.8%)
mTICI 1		1 (0.8%)
mTICI 2a		4 (3.0%)
mTICI 2b		91 (68.7%)
mTICI 3		36 (26.9%)

Table 3:

Significant predictors of cost

	P Value	Partial Eta²	Exponentiated β-Coefficient (95% CI)^{^b}
Primary analysis: all ACLVO^{^a} (n = 341)
FIV (mL)	<.0001	20.87%	1.0037 (1.0029–1.0048)
PH types 1 and 2	<.0001	5.22%	1.6399 (1.3050–2.0610)
NIHSS	.0024	2.76%	1.0161 (1.0057–1.0266)
Obstructive sleep apnea	.0040	2.48%	1.3391 (1.0981–1.6329)
Age (yr)	.0089	2.06%	0.9946 (0.9906–0.9986)
Ipsilateral carotid stenosis	.0195	1.65%	1.1902 (1.0285–1.3774)
Subgroup analysis by treatment group
Endovascular therapy (n = 133)
FIV (mL)	.0003	10.03%	1.0024 (1.0011–1.0037)
PH type 1	.0006	9.24%	2.4942 (1.4926–4.1680)
Obstructive sleep apnea	.0018	7.71%	1.5211 (1.1727–1.9730)
NIHSS	.0120	5.08%	1.0206 (1.0046–1.0368)
Ipsilateral carotid stenosis	.0290	3.85%	1.2481 (1.0234–1.5221)
mTICI score^{^c}	.0364	1.79%	Multilevel variable
IV tPA-only (n = 61)
FIV (mL)	<.0001	29.11%	1.0043 (1.0025–1.0060)
NIHSS	.0300	7.99%	1.0273 (1.0273–1.0524)
No reperfusion therapy (n = 147)
FIV (mL)	<.0001	27.92%	1.0042 (1.0031–1.0053)
PH types 1 and 2	.0005	8.37%	2.6371 (1.5458–4.4988)
Obstructive sleep apnea	.0300	3.29%	1.5057 (1.0407–2.1784)
Age (yr)	.0330	3.20%	0.9925 (0.9857–0.9937)

↵a Controlled for treatment type: endovascular, IV-tPA, and no reperfusion therapy.
↵b The exponentiated β-coefficient represents the multiplicative change in cost associated with an increase in 1 unit of a continuous variable (or the presence of a categoric variable), while holding all other variables constant.
↵c Multilevel variable with F-distribution.

Table 4:

Expected cost burden per additional infarct volume^{^a}

Increased Stroke Burden (mL)	Expected Increase in Hospitalization Cost	Net Expected Cost Increase	Cost per Additional 1 mL of Stroke Burden
1	0.37%	$75.11	$75.11
10	3.75%	$763.75	$76.38
50	20.23%	$4116.33	$82.33
100	44.54%	$9065.25	$90.65
150	73.78%	$15,015.15	$100.10
200	108.93%	$22,168.52	$110.84
247.2^{^b}	148.61%	$30,244.13	$122.35
300	202.00%	$41,108.50	$137.03
350	263.09%	$53,539.62	$152.97
400	336.52%	$68,485.11	$171.21
413.3^{^c}	358.44%	$72,946.41	$176.50

↵a With reference to mean cost = $20,351.23 and primary multivariable analysis (Table 3), holding all variables constant while increasing the FIV.
↵b Range of FIVs observed (fifth–95th percentile).
↵c Full range of observed FIVs (0–100th percentile).