Heart failure: B-natriuretic peptide could help diagnose and exclude it.

Clinical bottom line (level 1b)

Two-thirds of patients referred for echocardiography for suspected heart failure had an LV ejection fraction < 50%.
A B-natriuretic peptide level > 75 pg/ml made LV dysfunction more likely (LR + 15) , and a level < 49 pg/ml made it less likely (LR - 0.029) .
LV dysfunction was more likely with
- clinical symptoms of heart failure (LR + 9.6)
- a history of heart failure
No clinical feature could safely exclude LV dysfunction.

Krishnaswamy et al: Am J Med 2001; 111 : 274-279

Expires May 2004

The study

Setting: Veterans Affairs hospital, USA

400 patients (aged mean 66, 97% male) referred for echocardiography to assess ventricular function

Excluded if

echocardiogram for valve disease, assessment of presence of vegetation, or to rule out a cardiac cause for a stroke

Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:

2-D echocardiography: abnormal ventricular function if ejection fraction < 50%

Diagnostic test: B-natriuretic peptide

The evidence

pre-test probability of abnormal LV function: 63%, (95% CI: 59% to 68%)

diagnostic test	LV dysfunction	no LV dysfunction	LR (95% CI)	post-test probability
BNP: 345 pg/ml or higher	93	1	53 (7.4 to 380)	99%
BNP: 160-344 pg/ml	73	1	42 (6.0 to 300)	99%
BNP: 110-159 pg/ml	26	1	15 (2.1 to 110)	96%
BNP: 75-109 pg/ml	25	1	15 (2.0 to 110)	96%
BNP: 62-74 pg/ml	10	11	0.53 (0.23 to 0.66)	48%
BNP: 49-61 pg/ml	23	33	0.40 (0.25 to 0.66)	41%
BNP: < 49 pg/ml	5	99	0.029 (0.012 to 0.070)	5%
total	253	147

diagnostic test	LV dysfunction	no LV dysfunction	LR+ (95% CI)	post-test probability	LR- (95% CI)	post-test probability
clinical symptoms of heart failure	132	8	9.6 (4.8 to 19)	94%	0.51 (0.44 to 0.58)	47%
history of heart failure	102	0	- (20 to infinity)	100%	0.60 (0.54 to 0.66)	51%
coronary heart disease	144	42	2.0 (1.5 to 2.6)	77%	0.60 (0.51 to 0.72)	51%
shortness of breath	153	53	1.7 (1.3 to 2.1)	74%	0.62 (0.51 to 0.75)	52%
oedema	78	28	1.6 (1.1 to 2.4)	74%	0.85 (0.76 to 0.96)	60%
total	253	147

Citation

Krishnaswamy P, Lubien E, Clopton P, et al: utility of B-natriuretic peptide levels in identifying patients with left ventricular dysfunction of diastolic dysfunction. Am J Med 2001; 111 : 274-279

Search Terms: from ACP Journal Club
Contributor: Chris Ball, May 2002
Reviewer:

_{Clinical Question.}

_Patient	_{suspected heart failure referred for echocardiography}
_{Intervention or Exposure}	_{B-natriuretic peptide}
_Outcome	_{LV dysfunction}