Continuous right ventricular volumetry by fast-response thermodilution during right ventricular ischemia: head-to-head comparison with conductance catheter measurements.

OBJECTIVE

To evaluate the accuracy of right ventricular ejection fraction and right ventricular end-diastolic volume obtained by volumetric pulmonary artery catheter, using the conductance catheter as reference method.

DESIGN

Prospective, comparative study.

SETTING

Research laboratory of a university hospital.

SUBJECTS

Seven young female German landrace pigs.

INTERVENTIONS

Ligation of the distal right coronary artery to induce temporary acute ischemia.

MEASUREMENTS AND MAIN RESULTS

Right ventricular ejection fraction and right ventricular end-diastolic volume were measured simultaneously with a volumetric pulmonary artery catheter and the conductance catheter technique (reference method), in an animal model of acute right ventricular ischemia. Measurements were performed at baseline, during ischemia, and during reperfusion. The methods were compared with Bland-Altman analyses and their diagnostic accuracy to detect ischemia was quantified by receiver operating characteristic curve analysis. For right ventricular ejection fraction measurements, Bland-Altman analysis indicated a bias of -9.9% indicating underestimation by pulmonary artery catheter with limits of agreement ranging from -26% to 6.1%. The data showed a trend for more underestimation at higher right ventricular ejection fraction values. For right ventricular end-diastolic volume, a bias of 31 mL, indicating overestimation by pulmonary artery catheter was found. Limits of agreement ranged from -25 mL to 88 mL. Ischemia induced a decrease in right ventricular ejection fraction and an increase in right ventricular end-diastolic volume, as expected, which was detected by conductance catheter with a significant higher diagnostic accuracy indicated by a receiver operating characteristic area under the curve of 0.98 (p < .001) and 0.92 (p < .001), respectively. Corresponding sensitivity and specificity were 100% and 86%, respectively, for right ventricular ejection fraction conductance catheter (cutoff value = <40%), and 86% and 100% for right ventricular end-diastolic volume conductance catheter (cutoff value = >94 mL). However, diagnostic accuracy for right ventricular ejection fraction pulmonary artery catheter and end-diastolic volume pulmonary artery catheter to detect ischemia was limited with area under the curve 0.76 (p = .06) and 0.57 (p = .65), respectively.

CONCLUSIONS

Accuracy of volumetric pulmonary artery catheter in conditions of right ventricular ischemia is low and inadequate for diagnosis of right ventricular ischemia and failure.