Assessment of Primary Care Physicians' Use of a Pocket Ultrasound DeviceTM to Measure Left Ventricular Mass in Patients with Hypertension

Paul Bornemann; Jeremy Johnson; Samuel Tiglao; Amina Moghul; Sheila Swain; Gina Bornemann; Mike Lustik

doi:10.3122/jabfm.2015.06.140314

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Figure 1.
Parasternal long-axis view of the heart with measurements. LA, left atrium; LV, left ventricle; LVEDD, left ventricular end diastolic diameter; PWT, posterior wall thickness; RV, right ventricle; SWT, septal wall thickness.
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Figure 2.
Bland-Altman plots of differences in mean measurements of septal wall thickness (A), posterior wall thickness (B), left ventricular end diastolic diameter (C), and left ventricular mass index (D) between primary care physician (PCP) and cardiologist groups. In each graph, the dotted lines represent the 95% confidence intervals of the percentage difference between PCPs and cardiologists. The solid line represents the estimated mean difference. The legend to the right identifies the different PCP examiners.
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Figure 3.
Bland-Altman plot of the difference in mean calculations verus sequence number. The dotted lines represent the 95% confidence intervals of the percentage difference between the primary care physicians (PCPs) and cardiologists. The solid line represents estimated mean difference. The legend to the right identifies the different PCP examiners.

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Table 1. Number of Ultrasound Examinations Performed by Each Primary Care Physician during the Study
Experience Examinations (n)
PCP1 Resident 13
PCP2 Faculty 47
PCP3 Resident 8
PCP4 Resident 33
101
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Table 2. Characteristics of the Study Population
Variable Value
Population studied (n) 101
Age, years (mean [SD]) 60.5 (19)
Sex (%)
Female 62.4
Male 37.6
Body mass index (mean [SD]) 28.67 (5.33)
SD, standard deviation.
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Table 3. Differences in Means between Primary Care Physicians and Cardiologists
Measurement Difference in Means 95% Confidence Interval^* SD P Value^{^†}
SWT (mm) 0.4 −0.3 to 1.0 3.3 .232
PWT (mm) 1.2^* 0.3–2.1 4.4 .007
LVEDD (mm) −2.1^* −3.8 to −0.5 8.5 .013
LVMI (g/m²) 0.5 −6.6 to 7.6 36.1 .885
↵* Confidence intervals are calculated by standard error of the means.
↵† P < .05.
LVEDD, left ventricular end diastolic diameter; LVMI, left ventricular mass index; PWT, posterior wall thickness; SD, standard deviation; SWT, septal wall thickness.

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Table 4. Sensitivity and Specificity of Primary Care Physician Examinations with Cardiologist Examinations as Gold Standard for Detecting Left Ventricular Hypertrophy^*

Data Set	Sensitivity (95% CI)	Specificity (95% CI)	PPV (95% CI)	NPV (95% CI)	+LR	−LR
Full Set (n = 101)	0.73 (0.59–0.87)	0.75 (0.64–0.86)	0.63 (0.48–0.77)	0.83 (0.73–0.92)	2.96	0.39
>35 Exams^{^†} (n = 15)	0.89 (0.68–1.00)	0.67 (0.29–1.00)	0.80 (0.55–1.00)	0.80 (0.45 to −1.00)	2.62	0.19

↵† The sensitivity and specificity of any exams performed after completing the first 35 examinations.
↵* Left ventricular hypertrophy is defined as left ventricular mass index >95 g/m² for women and >115 g/m² for men.
CI, confidence interval; +LR, positive likelihood ratio; −LR, negative likelihood ratio; NPV, negative predictive value; PPV, positive predictive value.