Scott A Reid

Publications (2)3.1 Total impact

• Article: Quantification of pulmonary autograft characteristics using magnetic resonance imaging.

  Scott A Reid, Peter G Walker, John Fisher, Zsolt L Nagy, John P Ridgway, Mohan U Sivananthan, Kevin G Watterson
  [show abstract] [hide abstract]
  ABSTRACT: The diameters and distensibility of the native pulmonary root and their effect on pulmonary autograft performance were examined pre- and postoperatively using cardiac ultrasound and magnetic resonance imaging (MRI). Eight patients undergoing the Ross procedure were prospectively involved. The diameters of the native aortic, native pulmonary and autograft roots were measured at the level of the annulus, sinus, sinotubular junction and in the main root using MRI through the cardiac cycle. Ultrasound was also used to estimate the degree of regurgitation, both pre- and postoperatively. The pulmonary root implanted into the systemic circulation increased in size but decreased in distensibility significantly at the sinus, sinotubular junction and main root, but not at the annulus. Postoperatively, the pulmonary autograft annulus showed a similar size and distensibility to that of the native aortic annulus. A wide range of aortic annular sizes (22-30 mm) produced clinically competent valves postoperatively. All undersized pulmonary valves showed only trivial regurgitation postoperatively. Although there was no clear correlation between root shape and valve insufficiency, two patients with mild and moderate autograft regurgitation both had divergent pulmonary roots (diameter at sinotubular junction > annulus diameter) preoperatively. The pulmonary autograft using the root replacement technique functioned well in all but one case. The shape of the native pulmonary root may be a determinant of early autograft regurgitation, as well as the diameter and the size mismatch between the great arteries.
  The Journal of heart valve disease 02/2004; 13(1):78-85. · 0.81 Impact Factor
• Source

  Available from: Peter Walker

  Article: The quantification of pulmonary valve haemodynamics using MRI.

  Scott A Reid, Peter G Walker, John Fisher, Z Nagy, John P Ridgway, Kevin G Watterson, Mohan U Sivananthan
  [show abstract] [hide abstract]
  ABSTRACT: The optimum slice location within the pulmonary root to quantify pulmonary valve haemodynamics was examined using magnetic resonance (MR) phase velocity mapping. MRI was carried out on 15 patients with congenital aortic valve disease. Although the patients had aortic valve disease, all measurements were made on the pulmonary valve. Systolic (Q(SYS)) and diastolic (Q(DIAS)) blood flow volume and cardiac index (CI) were determined at four pulmonary artery locations. The change in diastolic flow volume relative to slice 1, closest to the pulmonary valve, was also calculated. For a change in axial position of 1.5 cm, i.e. from 0.5 to 2 cm from the annulus, there was a change in diastolic flow volume of 4.4 ml. There was a significant increase in the mean diastolic flow from 3.4 to 7.7 ml (p = 0.01 between slice positions 0.5 and 2 cm. However, there was no significant change in CI, 3.4-3.7 l/min/m2 (p = 0.14) over the same distance. We believe that two factors are responsible for these results. The first is that of compliance, whose effects can be minimized by placing the MR slice close to the valve, however, this will not account for the second factor, being that of valve motion, and hence diastolic pulmonary valve flow or regurgitant volume will be underestimated. The degree of underestimation may only be important at mild and moderate levels of regurgitation or if changes in regurgitation are to be temporally measured.
  The International Journal of Cardiovascular Imaging 07/2002; 18(3):217-25. · 2.29 Impact Factor