Single Contrast Injection Research Articles

Digital angiographic assessment of the physiological changes to the regional microcirculation induced by successful coronary angioplasty.

Impulse response analysis of digital coronary angiographic images calculates a parameter known as the mean transit time of the microcirculation (Tmicro). This has been shown to accurately assess the regional microcirculatory response to proximal stenosis in relation to flow. Our goal was to apply impulse response analysis to patients undergoing successful angioplasty and to quantify the induced physiological changes with respect to quantitative angiographic measurements of stenosis dimensions. We studied 24 patients before and after successful single-vessel percutaneous transluminal coronary angioplasty (PTCA). Minimal luminal stenosis area was increased from 0.9 +/- 0.6 before PTCA to 4.1 +/- 1.3 mm2 after PTCA (P < .0001). In all patients this was accompanied by an increase in the inverse of Tmicro (Tmicro-1), from 8.5 +/- 3.0 to 26.5 +/- 9.0 min-1 (P < .0001) with a linear correlation between Tmicro-1 and minimal luminal stenosis area (r = .73; SEE = 7.74). Stenosis flow reserve, estimated by integration of stenosis dimensions, increased in all patients from 1.8 +/- 1.0 to 4.5 +/- 0.4 after PTCA (P < .01). A comparison of Tmicro-1 with stenosis flow reserve revealed a nonlinear relation. In 16 patients undergoing PTCA of the left anterior descending or circumflex artery, contrast injections into the left main stem allowed simultaneous measurements of Tmicro-1 in the adjacent, nonstenotic artery. Adjacent artery Tmicro-1 did not change after PTCA (25.8 +/- 6.2 compared with 25.6 +/- 6.8 min-1 before PTCA; P = NS); moreover, Tmicro-1 of the dilated artery measured after PTCA was equivalent to the nonstenotic adjacent artery, indicating normalization of microcirculatory responses. These data suggest that Tmicro-1 determined by digital angiographic impulse response analysis of a single contrast injection under resting flow conditions may be a practical method to assess the regional microcirculatory response to changes in stenosis severity effected by coronary angioplasty.

Angiographic right and left ventricular volume determination in normal infants and children.

Right and left ventricular volumes were calculated from bi-plane cineangiograms using a previously descriped parallelepiped method. Seventeen children, 1 month-10 years of age, were studied. Mean right ventricular end-diastolic volume (EDV) was 64 ml/m2 for infants, 78 ml/m2 for children. Mean right ventricular end-systolic volume (ESV) was 30 ml/m2 for both age groups. Left ventricular EDV and ESV were smaller than their right ventricular correlates by 23% and 56%, respectively. Mean right ventricular ejection fraction was 0.52 for infants and 0.61 for children. Mean left ventricular ejection fraction was 0.79 and 0.74, respectively. Speculation Cineangiographic determination of right and left ventricular volumes from a single contrast injection provides an excellent method to simultaneously evaluate hemodynamic performance of the two ventricles. Analysis of frame to frame volume changes, coupled with exact measurements of ventricular pressure changes, may allow calculation of ventricular distensibility and contractility.