Pulmonary hypertension in Nigerian adults with sickle cell anemia

Figures & data

Table 1 Clinical and demographic parameters of the study patients

Parameter	Minimum	Maximum	Mean ± SD
Age (years)	18.0	41.0	25.4 ± 5.14
Weight (kg)	29.0	74.0	51.0 ± 7.7
Height (m)	1.30	1.92	1.64 ± 0.08
BMI (kg/m^2)	14.2	24.98	19.0 ± 1.9
BSA (m^2)	1.02	1.99	1.52 ± 0.14
PCV (%)	20.0	35.0	26.7 ± 2.72
Hb Conc (g/dL)	6.67	11.7	8.91 ± 0.91
SBP (mmHg)	80.0	130.0	106.4 ± 10.2
DBP (mmHg)	50.0	86.0	64.5 ± 8.9

Abbreviations: BMI, body mass index; BSA, body surface area; PCV, packed cell volume; Hb Conc, hemoglobin concentration; SBP, systolic blood pressure; DBP, diastolic blood pressure.

Table 2 Relationship between PH and clinical parameters

Parameter	PH	No PH	p value
Age (years)	28.6 ± 5.8	23.4 ± 3.4	<0.001*
PCV (%)	25.6 ± 2.9	27.5 ± 2.4	0.001*
HR (beats/min)	84.0 ± 8.2	83.3 ± 3.7	0.616
SBP (mmHg)	107.5 ± 12.1	105.5 ± 8.9	0.264
DBP (mmHg)	64.5 ± 10.2	64.5 ± 8.2	0.987
BMI (kg/m^2)	19.1 ± 2.6	18.9 ± 1.4	0.810
BSA (m^2)	1.50 ± 0.15	1.53 ± 0.14	0.482
6MWD (m)	380.3 ± 63.2	474.3 ± 76.7	0.014*

Note:

* Statistically significant.

Abbreviations: PH, pulmonary hypertension; PCV, packed cell volume; HR, heart rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; BMI, body mass index; BSA, body surface area; 6MWD, 6-minute walk distance.

Table 3 Correlation strength between parameters of PH and 6MWD

Parameter	Pearson correlation coefficient	p value
TRVmax(m/s)	−0.442	<0.001*
AT (ms)	0.571	<0.001*
AT/RVET	0.557	<0.001*
MPAP (mmHg)	−0.571	<0.001*

Note:

* Statistically significant.

Abbreviations: PH, pulmonary hypertension; 6MWD, 6-minute walk distance; AT, right ventricular acceleration time; AT/RVET, ratio of right ventricular acceleration time to right ventricular ejection time; MPAP, mean pulmonary arterial pressure; TRV_max, maximum tricuspid regurgitant velocity.

Table 4 Relationship between PH and echocardiographic (A) structural parameters and (B) functional parameters

A
Parameter	PH present	PH absent	p value
LAD (cm)	3.9 ± 0.4	3.6 ± 0.4	<0.001*
LADi (cm/m^2)	2.63 ± 0.35	2.4 ± 0.2	<0.001*
LVIDD (cm)	5.1 ± 0.6	4.9 ± 0.5	0.080
LVIDDi (cm/m^2)	3.4 ± 0.5	3.21 ± 0.3	0.010*
EDV (mL)	125.7 ± 36.0	114.1 ± 28.6	0.080
EDVi (mL/m^2)	83.8 ± 23.5	74.2 ± 15.1	0.019*
ESV (mL)	42.8 ± 17.8	34.0 ± 11.3	0.080
ESVi (mL/m^2)	28.3 ± 11.8	22.0 ± 6.01	0.001*
IVST (cm)	0.90 ± 0.13	0.89 ± 0.14	0.937
LVPWT (cm)	1.08 ± 0.19	1.01 ± 0.17	0.090
RVWT (cm)	0.48 ± 0.07	0.38 ± 0.06	<0.001*
RVIDD (cm)	1.9 ± 0.5	1.6 ± 0.3	0.004*
RVIDDi (cm/m^2)	1.3 ± 0.3	1.1 ± 0.2	0.002*
LVMi	124.9 ± 31.4	109.6 ± 27.5	0.016*
RWT	0.39 ± 0.06	0.39 ± 0.05	0.985

B
Parameter	PH present	PH absent	p value
LVEF (%)	66.7 ± 7.3	70.4 ± 4.6	0.004*
LVFS (%)	37.4 ± 5.2	40.0 ± 3.9	0.009*
SV (mL)	83.0 ± 23.7	80.0 ± 19.3	0.523
SI (mL/m^2)	55.5 ± 15.8	52.2 ± 10.7	0.235
CO (L/min)	6.9 ± 1.9	6.7 ± 1.6	0.467
CI (L/min/m^2)	4.6 ± 1.3	4.3 ± 0.9	0.205
E^0 (m/s)	1.1 ± 0.2	1.02 ± 0.1	0.145
E/A	1.5 ± 0.3	1.6 ± 0.2	0.201
TDe′ (cm/s)	11.1 ± 2.0	12.6 ± 1.3	<0.001*
TDs′ (cm/s)	7.3 ± 1.2	8.4 ± 1.0	<0.001*
E/e′	9.8 ± 2.7	8.1 ± 1.0	<0.001*

Notes:

* Statistically significant. “i”, where seen as suffix, means parameter indexed to body surface area. E⁰, transmitral early diastolic velocity; E/A, ratio of transmitral early to late diastolic velocity; TDe′, early mitral annular septal tissue diastolic velocity; TDs′, mitral annular septal tissue systolic velocity; E/e′, ratio of transmitral early diastolic velocity to early mitral annular septal tissue diastolic velocity.

Abbreviations: PH, pulmonary hypertension; LAD, left atrial dimension; LVIDD, left ventricular internal dimension in diastole; EDV, end-diastolic volume; ESV, end-systolic volume; IVST, interventricular septal thickness; LVPWT, left ventricular posterior wall thickness; RVWT, right ventricular wall thickness; RVIDD, right ventricular internal diameter in diastole; LVM, left ventricular mass; RWT, relative wall thickness; LVEF, left ventricular ejection fraction; LVFS, left ventricular fractional shortening; SV, stroke volume; SI, stroke index; CO, cardiac output; CI, cardiac index.

Figure 1 Correlation between TRV_max and 6MWD.

Abbreviations: TRV_max, maximum tricuspid regurgitant velocity; 6MWD, 6-minute walk distance.

Table 5 (A) Significant correlates of TRV and (B) independent parameters linked to TRV

A
Parameter	Pearson’s correlation coefficient	p value
Age (years)	0.352	0.001
Hematocrit (%)	−0.326	0.001
6MWD (m)	−0.442	<0.001
LVEF (%)	−0.339	0.001
TDe′ (cm/s)	−0.279	0.007
TDs′ (cm/s)	−0.462	<0.001
E/e′ ratio	0.270	0.009
LADi (cm/m^2)	0.290	0.005
LVIDDi (cm/m^2)	0.434	<0.001

B
Parameter	Unstandardized coefficient	Standardized coefficient	p value
LADi (cm/m^2)	−0.880	−0.512	<0.001
TDs (cm/s)	−0.193	−0.428	0.002
Hematocrit (%)	−0.040	−0.203	0.021
Constant	3.411

Note: TDe′, early mitral annular septal tissue diastolic velocity; TDs′, mitral annular septal tissue systolic velocity; E/e′, ratio of early transmitral diastolic flow velocity to early mitral annular septal tissue diastolic velocity.

Abbreviations: TRV, tricuspid regurgitant velocity; 6MWD, 6-minute walk distance; LVEF, left ventricular ejection fraction; LADi, left atrial dimension index; LVIDDi, left ventricular internal diastolic dimension index; TDs, tissue Doppler systolic velocity.

Figure 2 Correlation between MPAP and 6MWD.

Abbreviations: MPAP, mean pulmonary arterial pressure; 6MWD, 6-minute walk distance.

Table 6 (A) Significant correlates of estimated MPAP and (B) independent parameters linked to mean pulmonary arterial pressure

A
Parameter	Pearson’s correlation coefficient	p value
Age (years)	0.467	<0.001
Hematocrit (%)	−0.467	<0.001
6MWD (m)	−0.571	<0.001
LADi (cm/m^2)	0.397	<0.001
LVEF (%)	−0.257	0.013
TDe′ (cm/s)	−0.322	0.002
TDs′ (cm/s)	−0.387	<0.001
E/e′ ratio	0.310	0.002
RVIDDi (cm/m^2)	0.249	0.016

B
Parameter	Unstandardized coefficient	Standardized coefficient	p value
Hematocrit (%)	−1.105	−0.270	0.003
Age (years)	0.678	0.315	0.004
LADi (cm/m^2)	10.283	0.288	0.004
6MWD (m)	−0.041	−0.231	0.038
Constant	67.237

Note: TDe′, early mitral annular septal tissue diastolic velocity; TDs′, mitral annular septal tissue systolic velocity; E/e′, ratio of early transmitral diastolic flow velocity to early mitral annular septal tissue diastolic velocity.

Abbreviations: MPAP, mean pulmonary arterial pressure; 6MWD, 6-minute walk distance; LADi, left atrial dimension index; LVEF, left ventricular ejection fraction; RVIDDi, right ventricular internal diastolic diameter indexed to body surface area.

Table 7 Independent parameters linked to 6MWD

Parameter	Unstandardized coefficient	Standardized coefficient	p value
TDs (cm/s)	23.522	0.452	0.003
RVIDDi (cm/m^2)	−63.494	−0.298	0.004
MPAP (mmHg)	−2.053	−0.365	0.023
Hematocrit (%)	5.394	0.232	0.024
Constant	278.400

Abbreviations: 6MWD, 6-minute walk distance; TDs, tissue Doppler systolic velocity; RVIDDi, right ventricular internal diastolic dimension index; MPAP, mean arterial pulmonary pressure.