Prediction of Pulmonary Arterial Pressure in Chronic Obstructive Pulmonary Disease by Radionuclide Ventriculography: Results
In group 1, Kr RVEF was measured at rest and correlated to the pulmonary hemodynamic measurements performed during the same week.
In group 2, “”Tc RVEF and the other noninvasive parameters were correlated to pulmonary arterial pressures and resistances measured simultaneously.
These consisted of linear, logarithmic and exponential correlations between noninvasive parameters and pulmonary hemodynamics.
The plotting of 81mKr RVEF and mean pulmonary arterial pressure, presented in Figure 2, shows that both parameters are correlated (r= — 0.75) though not perfectly.
Correlations between curve parameters derived from the ECG-gated right volume curve and mean pulmonary arterial pressure are presented in Table 2. None of these curve parameters correlates better with mean pulmonary arterial pressure than RVEF even when using a logarithmic or exponential correlation instead of a linear correlation. Figures 3 and 4 show the calculated parameters of the systolic and diastolic phases which correlate best with mean pulmonary arterial pressure, respectively first third ejection and filing rate.
The same results have been observed with the systolic pulmonary arterial pressure and the pulmonary vascular resistance index (Table 2).
In chronic obstructive pulmonary disease, pulmonary arterial hypertension frequently induces cor pulmonale and symptomatic right congestive heart failure with poor prognosis. The higher the pulmonary arterial pressure, the worse the prognosis. Therefore, the determination of this parameter seems interesting for both the evaluation and the follow-up of COPD patients. Since measuring pulmonary arterial pressure requires right heart catheterization, a traumatic and expensive procedure, a variety of other techniques have been proposed, including chest roentgenography, echocardiography, radionuclide angiography and others. Unfortunately, up to now, none of them has yielded accurate estimations of pulmonary arterial pressure.
Figure 2. Linear correlation between *”Kr right ventricular ejection fraction and mean pulmonary arterial pressure in 16 patients with COPD.
Figure 3. Linear correlation between first third ejection rate and mean pulmonary arterial pressure in 41 patients with COPD.
Figure 4. Linear correlation between first third filling rate and mean pulmonary arterial pressure in 41 patients with COPD.
Table 2—Linear Correlation Between Radionuclide and Hemodynamic Barometers.
|Pre-ejection period||ms||+ 0.10||+0.05||+0.14|
|Time to peak ejection rate||ms||+0.24*||+0.26*||+0.30*|
|Time to first third systole||ms||+0.24*||+0.23*||+0.28*|
|Total ejection time||ms||+ 0.04||+0.09||+0.14|
|First third ejection rate||count-s ~||-0.494:||-0.52*||-0.38*|
|Peak ejection rate||count’s||-0.29*||-0.35*||-0.28*|
|Mean ejection rate||count’s||-0.43*||-0.46*||-0.41*|
|First third/total ejection rate||count’s||+ 0.17||+0.10||+0.13|
|Rapid filling time||ms||-0.06||-0.04||-0.07|
|Slow filling time||ms||-0.25*||-0.23*||-0.20*|
|Time to peak filling rate||ms||+0.01||+0.01||-0.01|
|Time to first third diastole||ms||+0.02||+0.06||+0.05|
|Total filling time||ms||-0.26*||-0.24*||-0.22*|
|Peak filling rate||count’s||-0.13||-0.19||-0.15|
|First third filling rate||count’s||—0.34*||-0.35*||-0.29*|
|Mean filling rate||count’s||-0.23*||-0.27*||-0.22*|
|First third to total filling rate||-0.15||-0.19||-0.22*|
|KV ejection fraction||%||-0.61*||-0.63*||-0.54*|