Page 22 - Journal of Structural Heart Disease Volume 3, Issue 4

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Case Report
Figure 2. Left anterior oblique, 30°. 4-F terumo angle catheter in right atrium adjacent to a Genesis atrial stent (open arrow). Note the acute angulation of the stent compared with the atrial septum. The pressure wire was passed through the body of the stent with the radio-opaque end curled within the left atrium. The pressure sensor was located at the non-opaque-to-opaque junction of the wire.
which easily passed through the side cells of the stent and then traversed to the left atrium, we were able to measure the left atrial pressure at 12 mmHg with a right atrial pressure of 4 mmHg. Using left atrial pres- sure, the calculated PVR was 1.8 Wood units. As such, we determined that the patient was a satisfactory can- didate for bidirectional cavopulmonary anastomosis.
Patient 2 had a diagnosis of atrioventricular and ventriculoarterial discordance, hypoplastic left-sided right ventricle, left atrioventricular valve atresia, and pulmonary atresia. At three days of age, he had a mod- i ed right Blalock-Taussig shunt and balloon atrial septostomy for a restrictive atrial septum. He went on to have an atrial septal stent (5 × 16 mm Liberte, Bos- ton Scienti c, Marlborough, Massachusetts) placed at six weeks of age. At 3.5 months of age, the patient’s pre-bidirectional cavopulmonary anastomosis eval- uation showed an elevated mean pulmonary artery pressure of 21 mmHg. Left ventricular end diastolic pressure was 7 mmHg. Similar to the case of Patient 1, a catheter could not be passed through the atrial
septal stent to the left atrium, but a pressure wire was successfully passed through a side cell of the stent into the left atrium, and a direct pressure measure- ment was obtained (Figure 2). Left atrial pressure was signi cantly elevated at 16 mmHg compared with a right atrial pressure of 5 mmHg. PVR was calculated as 1.5 Wood units, making the patient a suitable can- didate for bidirectional cavopulmonary anastomosis.
Pulmonary pressures were elevated in both patients, but this was in the setting of left atrial hypertension secondary to a restrictive atrial septum (as the lumen of the previously placed stent was now too small for the size of the patient) with normal PVR. Both patients underwent bidirectional cavopulmonary anastomoses and had uneventful postoperative courses. The infor- mation obtained using pressure-sensing wires directly contributed to our management decisions and was in- strumental in ensuring that the patients were not de- nied the appropriate next-stage palliative surgery.
Discussion
For children with single ventricle physiology, the accurate assessment of PVR is essential as part of the preoperative evaluation to determine suitability for surgical palliation. For patients in whom measured pul- monary pressure suggests that PVR may be elevated, the perioperative risk becomes di cult to accurate- ly ascertain. The ability to directly measure left atrial pressure in these children to calculate PVR is critical for optimal surgical decision-making. Pulmonary capillary wedge pressure can be used as a surrogate for left atri- al pressure. However, there is some error in predicting left atrial pressures using this technique, which can be ampli ed at higher wedge pressure measurements [5]. Given that such a discrepancy could result in an erro- neously low PVR calculation, direct left atrial pressure measurement with a pressure-sensing wire may be more appropriate given the important clinical deci- sion based on these measurements. Future evaluation of the relationship between the pulmonary capillary wedge pressure and left atrial pressure in children with elevated left atrial pressures would be useful.
There is a paucity of published reports of pressure wire use in children with congenital heart disease. However, pressure wires have been safely and suc- cessfully used to measure pulmonary artery pressure
McGovern, E. et al.
Pressure Wire Use in Univentricular Heart Disease