Exercise Doppler: functional evaluation of right heart dynamics

[Cardiopulmonary exercise testing in exercise-induced pulmonary hypertension]

OBJECTIVE

To determine the accuracy of cardiopulmonary exercise-testing (CPET) in detecting exercise-induced pulmonary hypertension.

BACKGROUND

CPET plays a key role in the investigation of exertional breathlessness. Exercise-induced pulmonary hypertension has been recently demonstrated to be a cause of exertional dyspnea. However, the features of CPET associated with the condition are still unknown.

METHODS

We prospectively studied CPET and exercise echo-cardiography characteristics in 39 patients complaining of exertional breathlessness. Patients could be divided into 3 groups as follows: 1) control subjects having normal pulmonary arterial pressure at rest [pulmonary arterial systolic pressure < 35 mmHg] and at peak exercise [pulmonary arterial systolic pressure < 45 mmHg]; 2) patients having exercise-induced PH; 3) patients having resting PH. Results from CPET have been analyzed within each group.

RESULTS

Patients developing exercise-induced PH revealed an increased VD/VT ratio and CO2 gradient (P[a-ET]CO2) at peak exercise compared to controls (VD/VT at 0.38 +/- 0.1 vs 0.29 +/- 0.11 and P[a-ET]CO2 at 4,6 +/- 3,1 vs 1 +/- 3,8 mmHg). VD/VT and P[a-ET]CO2 were increased in patients with resting PH. A VD/VT ratio at peak exercise higher than 0.34 was 72.7% sensitive and 71% specific in predicting exercise-induced PH. Positive and negative predictive values were 72.7% and 70.1% respectively.

CONCLUSION

Patients with exercise-induced PH did not decrease or may increase dead space during exercise. Therefore CPET may be a useful tool in selecting patients who need to undergo further exercise haemodynamic investigations.

Range of tricuspid regurgitation velocity at rest and during exercise in normal adult men: implications for the diagnosis of pulmonary hypertension

OBJECTIVES

The aim of this study was to explore the full range of tricuspid valve regurgitation velocity (TRV) at rest and with exercise in disease free individuals. Additionally we examined the relationship of stroke volume (SV), cardiac output (CO) and TRV to exercise capacity.

BACKGROUND

Doppler evaluation of TRV can be used to estimate pulmonary artery systolic pressure (PASP). Most studies have assumed TRV < or = 2.5 m/s as the upper limits of normal. The full range of TRV with exercise has been incompletely defined.

METHODS

Highly conditioned athletes (n = 26) and healthy, active, young male volunteers (n = 14) underwent standardized recumbent bicycle exercise. Exercise parameters included: TRV, SV, CO, systolic (SBP) and diastolic (DBP) systemic blood pressure.

RESULTS

Tricuspid valve regurgitation, SV, HR and CO were significantly higher in athletes than in nonathletes over all workloads, including rest. Systolic blood pressure and DBP did not show significant differences between the two groups.

CONCLUSIONS

This study defines the upper physiologic limits of TRV at rest and during exercise in normals and provides a noninvasive standard for the diagnosis of pulmonary hypertension.

Five-year follow-up study of the prevalence and progression of pulmonary hypertension in systemic lupus erythematosus

The purpose of this study was to determine the prevalence and progression of pulmonary hypertension over a 5-year follow-up period in 28 patients with systemic lupus erythematosus (SLE) who were originally enrolled in an echocardiographic study of pulmonary hypertension in 1985 and 1986. Twenty healthy volunteers without cardiac or pulmonary disease participated as normal controls. Each patient and control underwent a complete Doppler echocardiographic study. Doppler echocardiographic recordings of tricuspid insufficiency, with saline contrast enhancement when necessary, were used to calculate pulmonary artery systolic pressure according to the modified Bernoulli equation. Doppler echocardiographic measurement of cardiac output was performed at rest for each subject, and pulmonary resistance was calculated by dividing the pulmonary artery systolic pressure by the cardiac output. These results were compared to results of the original studies to detect serial changes in pulmonary pressure and pulmonary resistance; results were also compared to the group of normal controls. The prevalence of pulmonary hypertension increased from 14% at the first study to 43% at follow-up. A significant increase in mean systolic pulmonary artery pressure was detected in the SLE patients during the follow-up period: 23.4 vs 27.5 mm Hg (p < 0.005). In addition, a significantly higher pulmonary artery pressure was detected in the SLE patients compared with the normal controls (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise capacity and hemodynamics in systemic lupus erythematosus: a Doppler echocardiographic exercise study

Although pulmonary hypertension is a well-described manifestation of systemic lupus erythematosus, there are few data regarding the pulmonary artery pressure response to exercise. We hypothesized that exercise capacity was reduced and that the pulmonary artery pressure response to exercise was abnormal in patients with systemic lupus erythematosus. To test these hypotheses, we performed Doppler exercise echocardiography in 18 patients with lupus and 10 normal control subjects. Exercise duration was significantly reduced in the patients with lupus (8.1 vs 14.4 minutes for control subjects, p < or = 0.001). Pulmonary artery pressure was significantly higher in the patients with lupus at rest and during the first two stages of exercise (p < 0.05). Cardiac indexes at rest were similar in the two groups, suggesting that increased pulmonary vascular resistance was the mechanism for the higher pulmonary pressure we observed. We conclude that abnormal exercise hemodynamics may contribute to reduced exercise capacity in patients with lupus.