Pulmonary blood supply in bidirectional cavopulmonary anastomosis with pulsatile pulmonary blood flow: quantitative analysis using radionuclide angiocardiography.

Abstract

Conclusions-Radionuclide angiocardiography allows the quantitative analysis of pulmonary blood supply in BCPA with sources of pulsatile blood flow except in patients with cavo-caval collaterals or bilateral BCPA. Non-pulsatile flow from BCPA is mainly directed to the ipsilateral lung, whereas pulsatile flow to the contralateral lung. Total perfusion of the ipsilateral lung is less than the perfusion of the contralateral lung. (Heart 1996;75:513-517) Keywords: congenital heart defects; cavopulmonary anastomosis; radionuclide angiocardiography; pulmonary blood flow.Surgical palliation of complex cardiac anomalies is being done increasingly by total cavopulmonary connection, on the basis that the right heart is dispensable.' In patients who do not fulfil criteria for total cavopulmonary connection2 the results are not satisfactory. We present a new non-invasive method for quantitative assessment of relative contribution of BCPA and the sources of pulsatile blood flow to the total pulmonary blood flow, as well as to the perfusion of each lung. Rationale Radionuclide angiocardiography allows regional flow measurement using a peripheral vein injection and external counting. The pulmonary blood supply in BCPA with a source of pulsatile blood flow consists of venous blood from the superior vena cava and pulsatile arterial blood from aortopulmonary connections or a stenotic pulmonary valve. In this situation, after tracer injection into the drainage area of the superior vena cava, the lung dye dilution curve is composed of two peaks caused by the cavopulmonary and arterial flows respectively. The relative contribution of these two sources to the overall lung perfusion may be calculated using integrals of the two respective parts of dilution curve in a manner similar to the calculation of intracardiac shunts.'718 Furthermore, by analogy to the measurement of cardiac output,'8 19 the total flow through both lungs may be calculated separately and compared. A gamma camera system enables direct visualisation of the superior to inferior vena cava collaterals and regional pulmonary blood flow during the radionuclide angiocardiography. Subsequent

The real fate of pulmonary arteries after bidirectional superior cavopulmonary anastomosis: is there a need for concern?

“…After surgery, only two patients had an index below this level. Similarly, our own experience demonstrated that a pulmonary artery originally smaller than normal on the side of the shunt can improve in size following a bidirectional cavopulmonary anastomosis, 15 corresponding with the demonstration by Reich et al 21 of preferential blood flow into such pulmonary arteries. Furthermore, when we calculated the Nakata index involving both the left and right pulmonary arteries in a subgroup of 23 patients from our previous study who had low pulmonary blood flow prior to the operation, a 29% increase was encountered after a median follow-up of 14 months.…”

Intrapulmonary arteriovenous shunting may be a universal phenomenon in patients with the superior cavopulmonary anastomosis: a radionuclide study

“…The lack of complete protection in this group may be explained by the uneven distribution of various sources of pulmonary blood supply. The BCPA provides up to 88% of blood flow to the ipsilateral lung and this may dilute the protective effect of hepatic factor from the competitive source 21. The occurrence of PAVM predominantly in the right lung following the Glenn procedure supports this hypothesis 1.…”