Angiographic Estimation of Right Ventricular Volume in Man

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Abstract
Although the feasibility of angiographic estimation of right ventricular (RV) volume (V) has been demonstrated, no method has been validated by comparison with independent measurements of volume, and none has been applied to the systematic analysis of RVV characteristics in man. In the present study, postmortem casts of the human RV were used to determine a regression analysis for RVV for biplane frontal and lateral films by the Simpson's rule technique (true volume = 0.749 calculated volume, r = 0.99, see 3.7 ml, for casts ranging in volume from 20 to 115 ml). This method was then employed to estimate RVV from biplane cineangiograms of 32 patients. The validity of RVV measurements in vivo was corroborated by close correlation of stroke volumes estimated independently by angiographic and indicator dilution methods (r = 0.98, see 4.1 ml). In nine patients with normal RV hemodynamics RV end-diastolic volume (EDV) averaged 81 ml/m2 (range 63 to 101 ml/m2); ejection fraction (EF) averaged 0.51 (range 0.40 to 0.66), values generally lower than the normal left ventricular EF. Of 14 patients with elevated RV systolic pressure (> 45 mm Hg), normal RV function was evidenced in eight by normal levels of EF and EDV; in the remaining six patients, EF was reduced and EDV was elevated, suggesting that dilatation occurred in these patients as a function of depressed RV myocardial performance. In six patients with left-to-right shunts RV EDV was also increased; however, in these patients normal levels of EF were observed, indicating that the accommodation to volume overload was accomplished through the Starling mechanism. Finally, in six of 13 patients with reduced levels of cardiac output, RV EDV was increased and EF reduced, signifying that impaired RV myocardial function contributed to depression of over-all cardiac performance. It is concluded that the biplane angiographic method provides a practical, accurate means of quantitating RVV characteristics, including the magnitude of volume overload as well as the level of RV myocardial performance.