Elevation of tricuspid regurgitant jet velocity, a marker for pulmonary hypertension in children with sickle cell disease

Abstract Pulmonary hypertension (PHT) has emerged as a frequent cause of increased morbidity and mortality in adults with sickle cell disease (SCD). However, the incidence, prevalence and etiology of PHT in children with SCD are currently unknown. An elevated tricuspid regurgitant jet velocity (TRJV) ≥ 2.5 m/sec on Doppler echocardiogram (ECHO) in adults may predict PHT usually diagnosed by traditional cardiac catheterization. We hypothesized that routinely measuring TRJV in children and young adults with SCD was feasible and that TRJV correlated with degree of baseline hemolysis. Methods Using a standard protocol, we prospectively measured steady state TRJV in a convenience, cross-sectional sample of 43 patients (mean age 14.2±2.8 years, range 10 to 20) with hemoglobin (Hb) SS, SC or S-β0 thalassemia at our institution as part of a PHT screening initiative beginning December 2005. Patients on chronic transfusions were excluded. The relationship between TRJV and same day laboratory studies and clinical data obtained from patient charts was examined. Results TRJV was not measurable in 5 of 43 (12%) patients, due presumably to normal pulmonary artery systolic pressures. Neither right ventricular hypertrophy nor decreased septal wall motion, both suggestive of PHT, was present when TRJV could not be determined. In the remaining 38 studies in which TRJV could be quantified (mean 2.34 m/sec±0.44), TRJV was ≥ 2.5 m/sec in 13 patients. Using Pearson’s correlation coefficient, we found a significant correlation between TRJV and LDH (r=0.54, p=0.01), with higher TRJV associated with higher LDH. There were also significant, though more modest, positive correlations between TRJV and WBC (r=0.37, p=0.05) and reticulocyte count (r=0.40, p=0.05) and a significant negative correlation between TRJV and Hb (r= -0.46, p=0.01). Using t-test for independent samples, we found a significant difference in mean LDH (458 IU/L±192 vs. 338 IU/L±144, p=0.037), Hb (8.7 g/dL±1.3 vs. 10.2 g/dL±1.6, p=0.008) and reticulocyte count (17.3%±10.3 vs. 10.7%±6.9, p=0.027) between patients with TRJV ≥ 2.5 and <2.5 m/sec. A difference approaching significance in total WBC (11.4 x103/μL±5.3 vs. 8.3 x103/μL ±3.2, p=0.075) was also observed between the two groups. We found neither a significant difference in mean values between the two groups nor significant relationships with TRJV when we examined platelet count, plasma free Hb, percent fetal Hb or total bilirubin. Using Fisher’s Exact Test, we did not demonstrate in our small cohort a difference in the proportion of patients with TRJV ≥ 2.5 or < 2.5 m/sec who had a history of hydroxyurea use, acute chest syndrome, frequent pain, asthma, splenectomy, gallstones, priapism, exchange transfusion, heart disease or tonsilloadenoidectomy. Conclusions We conclude that TRJV by ECHO is quantifiable in most children and young adults being evaluated for PHT and that a higher LDH and reticulocyte count and a lower Hb at baseline are observed more frequently with elevated TRJV. Larger cohort studies are needed to test the predictive value of one or more of these markers of hemolysis. Although long term outcomes associated with elevated TRJV, as an indication of PHT, in children with SCD remains unclear, decreasing hemolysis in this population may represent an early therapeutic target in the prevention of future clinically significant PHT.

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Pulmonary Hypertension in Sickle Cell Disease: Cardiopulmonary Evaluation and Response to Chronic Phosphodiesterase 5 Inhibitor Therapy.

Blood ◽

10.1182/blood.v104.11.235.235 ◽

2004 ◽

Vol 104 (11) ◽

pp. 235-235 ◽

Cited By ~ 7

Author(s):

Roberto F. Machado ◽

Sabrina E. Martyr ◽

Anastasia Anthi ◽

Gregory J. Kato ◽

Lori A. Hunter ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Sickle Cell Disease ◽

Sickle Cell ◽

Functional Capacity ◽

Cell Disease ◽

Walk Distance ◽

Jet Velocity ◽

Minute Walk Distance ◽

Minute Walk ◽

Tricuspid Regurgitant Jet Velocity

Abstract Pulmonary hypertension (PH) is a risk factor for mortality in Sickle Cell Disease, but it is unclear whether pulmonary hypertension is a marker or a direct cause of mortality. To better understand the pathophysiology of pulmonary hypertension in patients with sickle cell disease we performed evaluations of cardiopulmonary function in sickle cell disease patients with pulmonary hypertension (n= 15, mean age = 41 ± 2.4 years, males = 7, HbSS = 15, mean Hb = 8.3 ± 0.2 g/dl, mean tricuspid regurgitant jet velocity = 3.2 ± 0.11 m/s) compared to matched controls with sickle cell disease without pulmonary hypertension (n=11, mean age=40.2 ± 2.5 years, males=4, HbSS=11, mean Hb=8.5 ± 0.3 g/dl, mean tricuspid regurgitant jet velocity = 2.28 ± 0.07 m/s). To evaluate if specific therapy for pulmonary hypertension has any impact on systolic pulmonary artery pressure (PAP), estimated by tricuspid regurgitant jet velocity (TRJ), and functional capacity, measured by six-minute walk test (a well validated surrogate of functional capacity and response to therapy in patients with other causes of pulmonary hypertension), we treated 14 patients with sickle cell disease and pulmonary hypertension (mean age = 40 ± 2.5 years, males = 3, HbSS = 14, mean Hb = 8.8 ± 0.6 g/dl, mean TRJ = 3.4 ± 0.1 m/s) with sildenafil for at least three months. When compared to controls pulmonary hypertension patients had lower maximal oxygen consumption (VO2 max (% predicted), +PH: 44 ± 4, −PH: 55 ± 4; P=0.41), walked shorter six-minute walk distance (meters, +PH: 308.5 ± 53.8, −PH: 427.1 ± 44.6; P=0.03), demonstrated greater degree of interstitial lung disease by chest CT (P < 0.05), and more perfusion impairments measured by ventilation perfusion scan (P < 0.05). Six-minute walk distance correlated directly with maximal oxygen consumption (R=0.6; P=0.01), and inversely with mean pulmonary arterial pressure (R= −0.5; P=0.03) and tricuspid regurgitant jet velocity (R= −0.6;P=0.002), suggesting that the test is an adequate surrogate of functional capacity and response to therapy in pulmonary hypertension patients with sickle cell disease. Chronic treatment with sildenafil (up to 100 mg TID) decreased pulmonary arterial pressure (PAP mmHg, baseline: 50 ± 4.4, sildenafil: 41 ± 2.5; P=0.04) and increased six-minute walk distance (meters, baseline: 394 ± 31, sildenafil: 476 ± 26: P= 0.02). Sildenafil was well tolerated with only 2 patients stopping the drug due to headaches. We also observed 3 episodes of transient eyelid edema not requiring discontinuation of drug. Priapism was not observed in the 3 males treated (2 on exchange transfusion therapy, 1 with erectile dysfunction). In conclusion, we find that in patients with sickle cell disease, 1) pulmonary hypertension, though relatively mild, is associated with severe impairments in cardiopulmonary function, 2) traditional markers of functional capacity such as six-minute walk test can be utilized in this population as a therapeutic endpoint for clinical trials, 3) and therapy with sildenafil seems to have a favorable impact on pulmonary pressures and functional capacity.

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Acute on Chronic Pulmonary Hypertension in Patients with Sickle Cell Disease.

Blood ◽

10.1182/blood.v104.11.1669.1669 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1669-1669 ◽

Cited By ~ 4

Author(s):

Gregory J. Kato ◽

Sabrina Martyr ◽

Roberto Machado ◽

Vandana Sachdev ◽

Inez Ernst ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Steady State ◽

Sickle Cell Disease ◽

Mortality Rate ◽

Sickle Cell ◽

Hemoglobin Concentration ◽

Cell Disease ◽

Marked Rise ◽

Jet Velocity ◽

Tricuspid Regurgitant Jet Velocity

Abstract Secondary pulmonary hypertension (PHT), defined as a tricuspid regurgitant jet velocity (TRV) > 2.4 meters/second at rest, has been identified as an emerging complication in patients with sickle cell disease, with 32% prevalence. Patients with sickle cell pulmonary hypertension tend to have a higher mortality rate than patients with primary PHT at comparable pulmonary artery pressures (PAP). We analyzed prospectively obtained Doppler echocardiography measurements from 11 patients in steady-state and during vaso-occlusive crisis episodes or during exercise to determine whether pulmonary pressures became further elevated during stress. We found that tricuspid regurgitant jet velocity is significantly further elevated during vaso-occlusive crisis (2.61 ± 0.03 vs. 2.81 ± 0.06 m/sec (mean ± SEM), p = 0.01)(Fig. A). We assessed other laboratory parameters and found associated significant decreases in hemoglobin concentration (9.3 ± 0.3 vs. 8.4 ± 0.3 gm/dL, p = 0.02)(Fig. B), and significant elevations in lactate dehydrogenase (381 ± 39 vs. 442 ± 49 IU/L, p = 0.02)(Fig. C). These data are consistent with increased hemolysis during vaso-occlusive crisis, and the association of increased hemolysis with acute exacerbation of PHT in patients with SCD. In three patients at steady state, exercise echocardiograms were performed, showing acute marked rise in TRV during exercise (2.80 ± 0.12 vs. 3.37 ± 0.17 m/sec, p = 0.02)(Fig. D). These data bring to light several important points in the clinical assessment of tricuspid regurgitant jet velocity in patients with sickle cell disease. First, the relatively mild steady state PHT in patients with SCD is associated with previously unappreciated acute increases in PAP that may explain the high mortality rate in this population. This might be responsible for sudden death occurring during vaso-occlusive crisis or physical exertion. Second, this acute rise is associated with markers of increased hemolysis, further implicating hemolysis-associated derangement of nitric oxide homeostasis, endothelial function and PHT. Third, exercise measurements of TRV may be indicated in the clinical evaluation of patients with SCD and dyspnea on exertion, since it may unmask otherwise unappreciated PHT. Figure Figure

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