Intraoperative Pulmonary Flow Study Research Articles

Which criteria should be used to select patients for the Fontan operation?

The Fontan operation has improved the survival of children born with single ventricle physiology. Selecting candidates for the Fontan operation may be difficult on borderline cases. No clear criterion has been established on the risk for staged Fontan palliation. Another aspect that remains controversial is the indications for fenestration. Intraoperative pulmonary flow study may identify high-risk patients for the procedure. In this report, the authors describe their results with Fontan procedures in children with pulmonary pressure >15 mmHg.

Mid-Term Outcomes After Unifocalization Guided by Intraoperative Pulmonary Flow Study.

Repair of tetralogy of Fallot (TOF) with major aortopulmonary collateral arteries (MAPCAs) requires unifocalization of pulmonary circulation, intracardiac repair with the closure of the ventricular septal defect, and placement of a right ventricle (RV) to pulmonary artery (PA) conduit. The decision to perform complete repair is sometimes aided by an intraoperative flow study to estimate the total resistance of the reconstructed pulmonary circulation. We reviewed patients who underwent unifocalization and PA reconstruction for TOF/MAPCAs to evaluate acute and mid-term outcomes after repair with and without flow studies and to characterize the relationship between PA pressure during the flow study and postrepair RV pressure. Among 579 patients who underwent unifocalization and PA reconstruction for TOF/MAPCAs, 99 (17%) had an intraoperative flow study during one (n = 91) or more (n = 8) operations to determine the suitability for a complete repair. There was a reasonably good correlation between mean PA pressure at 3 L/min/m2 during the flow study and postrepair RV pressure and RV:aortic pressure ratio. Acute and mid-term outcomes (median: 3.8 years) after complete repair in the flow study patients (n = 78) did not differ significantly from those in whom the flow study was not performed (n = 444). Furthermore, prior failed flow study was not associated with differences in outcome after subsequent intracardiac repair. The intraoperative flow study remains a useful adjunct for determining the suitability for complete repair in a subset of patients undergoing surgery for TOF/MAPCAs, as it is reasonably accurate for estimating postoperative PA pressure and serves as a reliable guide for the feasibility of single-stage complete repair.

Identification of high-risk Fontan candidates by intraoperative pulmonary flow study

BackgroundPre-Fontan risk stratification is still less than optimal. We aimed to evaluate the effectiveness of intraoperative pulmonary flow study (IOFS), in combination with conventional preoperative evaluation, in the identification of high-risk candidates for the Fontan operation. MethodData from 37 patients (age: 38.1 ± 4.9 months) who underwent the Fontan operation with IOFS were retrospectively reviewed. After anastomosing the Gore-Tex vascular graft to the confluent pulmonary artery, IOFS was performed through the graft at various cardiac indices (CI) (1–4 L/min/m2) generated from a roller pump. Mean pulmonary artery pressure (mPAP) and left atrial pressure (LAP) were recorded. The patients were divided into two groups: those who required Fontan circuit fenestration (group Ff) and those who did not (group Fn). ResultsEleven patients (29.7%) required fenestration, intraoperatively (n = 4) and postoperatively (n = 7), due to hemodynamic instability. Heterotaxy syndrome (P = 0.005) and atrioventricular valvar regurgitation (P = 0.04) were more frequent, and ventricle posterior wall thickness (VPWT) was higher (P = 0.024) in group Ff. On IOFS, the increase in mPAP by CI was sharper in group Ff than in group Fn (P < 0.001) owing to an increase in LAP. On multivariable analysis, mPAP at a CI of 3.0 L/min/m2 from IOFS was the only predictor of fenestration and correlated with preoperative VPWT (R = 0.543, P = 0.001). ConclusionsIOFS may be helpful to identify high-risk Fontan candidates, and high mPAP at CI of 3.0 L/min/m2 on IOFS is a significant predictor of the requirement for fenestration. VPWT is an important preoperative risk factor which correlates with the IOFS results.

Pulmonary flow study predicts survival in pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries

BackgroundWe hypothesized that mean pulmonary artery pressure (PAP) detected on a pulmonary flow study may predict medium-term survival and right ventricular systolic pressure (RVSP) in patients with pulmonary atresia (PA), ventricular septal defect (VSD), and major aortopulmonary collateral arteries (MAPCAs). MethodsFifty patients with PA/VSD/MAPCAs underwent unifocalization between 2000 and 2013, and 40 of these patients had a pulmonary flow study since 2003. Predictability of the mean PAP on VSD status, medium-term survival, reintervention, and RVSP were analyzed. ResultsForty-seven of the 50 patients (94%) had complete unifocalization at a median age of 11 months (range, 1-194 months), and 37 patients (74%) achieved VSD closure. Among the 40 patients who underwent a pulmonary flow study, the VSD was closed in 34 (85%), with salvage VSD fenestration in 4 (10%), and was intentionally left open in 6 (15%). Survival was 85.5% at 1 year and 78.5% at 5 years. A mean PAP ≥25 mm Hg was associated with worse survival (P = .011). Cox regression analysis identified a mean PAP ≥25 mm Hg as the sole predictor for death (P = .037). Patients with an open VSD had an increased risk of reoperation (P = .001) and pulmonary artery reintervention (P = .010), and had a trend toward increased risk of death (P = .059), compared with those with a closed VSD. ConclusionsPAP obtained from the intraoperative pulmonary flow study is associated with medium-term survival and late RVSP in patients with PA/VSD/MAPCAs. VSD closure for patients with a mean PAP ≥25 mm Hg on a flow study is considered high risk, and sensible judgment and a low threshold for VSD fenestration are required.

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: primary repair

Primary repair of pulmonary atresia (PA) with ventricular septal defect (VSD) and major aortopulmonary collaterals based on single-stage unifocalization was first reported in 1995. From a midline approach, all collaterals are extensively dissected, translocated in front of the oesophagus and/or the trachea, when required, and directly anastomosed to each other or to the native pulmonary arteries, whenever present, without interposition of prosthetic material. The need for concomitant VSD closure is assessed intraoperatively with a pulmonary flow study according to a standardized protocol. Pulmonary blood supply is established by valved conduit interposition in all patients, regardless of the suitability for VSD closure. Palliation with systemic-pulmonary shunt is reserved for selected cases. Between 1994 and 2015, 94 patients with a median age of 1.09 years (range 0.03-19) underwent single-stage unifocalization at our institution. In 78 (82.1%) of them, an intraoperative pulmonary flow study was utilized to assess acceptability for concomitant VSD closure, which was accomplished in 69 cases (73%). Intraoperatively, following VSD closure, the mean right ventricle-to-aortic pressure ratio was 0.49 ± 0.14. The overall mortality rate was 11.2% (n = 10), with an 82% survival at 12.5 years. At a median follow-up interval of 5.8 years, the right ventricle-to-aortic pressure ratio did not differ significantly from the early postoperative phase. The surgical results of primary repair of PA with VSD and major aortopulmonary collaterals based on single-stage unifocalization and an intraoperative pulmonary flow study are satisfactory and durable, despite the need for repeated percutaneous or surgical reinterventions.

Intraoperative pulmonary flow study for decision making in the comprehensive stage II hybrid procedure

Intraoperative pulmonary flow study for decision making in the comprehensive stage II hybrid procedure

The Functional Intraoperative Pulmonary Blood Flow Study Is a More Sensitive Predictor Than Preoperative Anatomy for Right Ventricular Pressure and Physiologic Tolerance of Ventricular Septal Defect Closure After Complete Unifocalization in Patients With Pulmonary Atresia, Ventricular Septal Defect, and Major Aortopulmonary Collaterals

The objective was to determine if intraoperative pulmonary artery (PA) flow studies after complete unifocalization correlate with postrepair hemodynamics for pulmonary atresia (PA), ventricular septal defects (VSD), and major aortopulmonary collaterals. Twenty patients (median age, 8 months; weight, 7.9 kg) underwent unifocalization between 2003 and 2008. A functional PA flow study was achieved by cannulating the unifocalized central PA before intracardiac repair and increasing flow incrementally to 2.5 L/min per m(2). Mean PA pressure (mPAP) was measured. The intent was to close the VSD for a mPAP of <30 mm Hg. Right ventricular systolic pressure (RVSP) and systemic systolic pressure were recorded. Total incorporated pulmonary segments, pulmonary segment artery ratio (ratio of incorporated segments to 18), and total neopulmonary artery index (the sum of major aortopulmonary collaterals and native PA index) were calculated. The VSD was successfully closed in 18 patients (90%). One attempted closure required an intraoperative fenestration. The study mPAP correlated with RVSP (rho=0.72; P=0.0027) and RVSP/systemic systolic pressure (rho=0.67; P=0.0063). Total neopulmonary artery index had a nonsignificant negative correlation with RVSP (rho=-0.42; P=0.079). Total incorporated pulmonary segments and pulmonary segment artery ratio were not correlated. Flow study mPAP had the highest accuracy in predicting successful VSD closure: area under the receiver-operator curve (0.83) versus total neopulmonary artery index (0.42), pulmonary segments (0.35), and pulmonary segment artery ratio (0.33). The intraoperative pulmonary flow study predicted postoperative physiology significantly better than did standard anatomic measures. Conventional measures should be used with caution when determining the possibility for complete repair.

Abstract 4567: Functional Intraoperative Pulmonary Blood Flow Study is a Sensitive Predictor of Right Ventricular Pressure and Successful VSD Closure for Following Complete Uniforcalization in Patients with Pulmonary Atresia with Ventricular Septal Defect and Major Aortopulmonary Collaterals

OBJECTIVE: We hypothesized mean pulmonary artery (PA) pressure obtained from an intraoperative pulmonary flow study would better predict the ability to close the ventricular septal defect (VSD) and better predict postoperative right ventricular systolic pressure (RSVP) than classic anatomical parameters after complete uniforcalization in patients with pulmonary atresia, VSD, and major aortopulmonary collaterals. METHODS: Sixteen consecutive patients (median, 11 mo, range 2 mo – 16 yrs) underwent one-stage (75%) or staged (25%) uniforcalization between 1/03 and 8/07. Intraoperative functional pulmonary blood flow study was achieved by inserting an arterial cannula in a reconstructed central PA. Flow was increased to 2.5 L/min/m2 while measuring PA pressure. RVSP and systemic systolic pressure (SBP) were recorded after VSD closure. Total neopulmonary artery index (TNPAI) (MAPCA + native PA index), total incorporated pulmonary vascular segments, and pulmonary segment artery ratio (PSAR) (ratio of incorporated segment to 18) were analyzed. Spearman rank correlation and area under the receiver operator characteristics curve (ROC-AUC) were used. RESULTS: The mean PA pressure on flow study was 21.8+/−6.2 mmHg (range, 11–31). Three patients had a pressure of &gt; 30 mmHg. The VSD was closed in 14 (87%). One patient with flow study mean PA pressure of 25 mmHg had suprasystemic RVSP and underwent intraoperative VSD fenestration. One with a flow study mean PA pressure of 30 mmHg had a prospective fenestrated VSD patch placed. There is a weak negative correlation between TNPAI and the flow study PA pressure (rho=−0.4, p=0.12). The flow study mean PA pressure was correlated with post-repair RVSP (rho=0.72, p=0.0027), and with RVSP/SBP ratio (rho=0.67, p=0.0063). TNPAI, total incorporated segments, and PSAR were not correlated with the postoperative RVSP or RVSP/SBP ratio. Flow study mean PA pressure had the highest sensitivity in predicting VSD closure: ROC-AUC (0.82) vs. TNPAI (0.46), pulmonary segment (0.64), and PSAR (0.64). CONCLUSIONS: Intraoperative pulmonary flow study predicted the ability of VSD closure better than total incorporated segments, TNPAI, and PSAR. Flow study mean PA pressure highly correlated with postoperative RVSP and RVSP/SBP ratio.

Unifocalization and repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries

Abstract Aim: To correlate anatomic and genetic features of paediatric patients with pulmonary atresia, ventricular septal defect (VSD) and multiple aortopulmonary collateral arteries with surgical outcome. Methods: 44 consecutive patients aged 33±40 mo underwent either primary one‐stage unifocalization (n=32) or palliative right ventricular outflow tract reconstruction (n=12) followed by secondary unifocalization and repair (n=10) based on preoperative morphometric and functional evaluation of pulmonary blood sources. Chromosome 22q11.2 microdeletion occurred in 41% of cases. Combined VSD closure during one‐stage procedures was guided by an intraoperative pulmonary flow study. Complete repair was accomplished in 35 cases (83%, 95% CI 72–95%). Variables examined included occurrence of confluent intrapericardial pulmonary arteries, central pulmonary arteries, confluent intraparenchymal pulmonary arteries, dominant collateral or pulmonary arteries, and chromosome 22q11.2 microdeletion. The sensitivity and specificity of the pulmonary flow study in predicting postoperative pulmonary haemodynamics were also tested. Results: Eight‐year actuarial survival and freedom from reoperation were 85% and 63%, respectively. Sensitivity and specificity of the pulmonary flow study were 94% and 100%, respectively. None of the anatomical variables examined was significantly related to the outcome of treatment. The only statistically relevant association was detected between survival and occurrence of 22q11.2 microdeletion (p&lt;0.003). Logistic analysis showed an increased likelihood of positive outcome in relation to first‐ (p&lt;0.02) or second‐stage (p&lt;0.04) complete correction. Conclusion: Morphology of pulmonary blood supply has no major impact on surgical outcome. Pulmonary flow study is a highly specific and sensitive intraoperative test. Chromosome 22q11.2 microdeletion remains the only variable significantly affecting survival.

Unifocalization and repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries

To correlate anatomic and genetic features of paediatric patients with pulmonary atresia, ventricular septal defect (VSD) and multiple aortopulmonary collateral arteries with surgical outcome. 44 consecutive patients aged 33 +/- 40 mo underwent either primary one-stage unifocalization (n = 32) or palliative right ventricular outflow tract reconstruction (n = 12) followed by secondary unifocalization and repair (n = 10) based on preoperative morphometric and functional evaluation of pulmonary blood sources. Chromosome 22q11.2 microdeletion occurred in 41% of cases. Combined VSD closure during one-stage procedures was guided by an intraoperative pulmonary flow study. Complete repair was accomplished in 35 cases (83%, 95% CI 72-95%). Variables examined included occurrence of confluent intrapericardial pulmonary arteries, central pulmonary arteries, confluent intraparenchymal pulmonary arteries, dominant collateral or pulmonary arteries, and chromosome 22q11.2 microdeletion. The sensitivity and specificity of the pulmonary flow study in predicting postoperative pulmonary haemodynamics were also tested. Eight-year actuarial survival and freedom from reoperation were 85% and 63%, respectively. Sensitivity and specificity of the pulmonary flow study were 94% and 100%, respectively. None of the anatomical variables examined was significantly related to the outcome of treatment. The only statistically relevant association was detected between survival and occurrence of 22q11.2 microdeletion (p < 0.003). Logistic analysis showed an increased likelihood of positive outcome in relation to first- (p < 0.02) or second-stage (p < 0.04) complete correction. Morphology of pulmonary blood supply has no major impact on surgical outcome. Pulmonary flow study is a highly specific and sensitive intraoperative test. Chromosome 22q11.2 microdeletion remains the only variable significantly affecting survival.

Increasing experience with integrated approach to pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

To validate the preliminary surgical results of 'integrated approach' to pulmonary atresia, ventricular septal defect (VSD), and multiple aortopulmonary collateral arteries by retrospective analysis of our center experience. Between 01/94 and 03/02, 37 patients aged 22 days to 13 years underwent surgery for pulmonary atresia, VSD, and multiple aortopulmonary collaterals. Case selection was based on preoperative calculation of total neopulmonary arterial index (TNPAI), pulmonary arterial index (PAI), and pulmonary arteries-to-collateral arteries lung segment perfusion ratio (S(pa):S(ca)). The decision for a possible VSD closure during one-stage procedures was based on an intraoperative pulmonary flow study. Twenty-five patients with a TNPAI equal to or greater than 150 mm(2)/m(2) underwent primary unifocalization, irrespective of PAI and S(pa):S(ca). Conversely, 12 patients with a TNPAI less than 150 mm(2)/m(2) and hypoplastic (PAI less than 100 mm(2)/m(2)) dominant (S(pa):S(ca) greater than 1) pulmonary arteries received a first-stage right ventricular outflow tract reconstruction, followed by unifocalization and repair (i.e. VSD closure) in nine cases. Among 34 patients who received total unifocalization, the overall repairability rate was 85% (first instance repairs: n=27; delayed VSD closure: n=2; 95% confidence interval, CI: 73-97%), with a survival rate at 7 years of 81%. Repaired survivors (n=26) are asymptomatic (n=22) or mildly symptomatic (n=4) at a follow-up interval of 43+/-28 months, with a 0.48+/-0.2 mean haemodynamic right ventricular/left ventricular pressure ratio, whereas palliated ones are waiting for either repair (n=3) or catheter study (n=2). Analysis of results has shown the following: (1) 100% (34/34 cases) feasibility of one-stage unifocalization in patients with a preoperative TNPAI equal to or greater than 150 mm(2)/m(2), whereas combined repairability rate was 79% only (95% CI: 65-93%); (2) 100% (12/12 cases) fulfillment of criteria for second-stage repairability (acquired TNPAI greater than 150 mm(2)/m(2)) in all patients treated with right ventricular outflow tract reconstruction; and (3) 93% (95% CI: 83-100%) overall accuracy of intraoperative flow study in predicting either postrepair mean pulmonary arterial pressure (VSD closed: n=23) or balanced pulmonary to systemic blood flow ratio (VSD left open: n=4). Increasing experience with 'integrated approach' to pulmonary atresia, VSD, and multiple aortopulmonaty collaterals has confirmed the preliminary results of our surgical series. The pulmonary flow study remains the most accurate intraoperative test for successful management of VSD during unifocalization procedures

One-stage complete unifocalization in infants: When should the ventricular septal defect be closed?

Background: The decision whether to close the ventricular septal defect at the time of unifocalization in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals may be difficult. The purpose of this study was to develop morphologic and physiologic methods to aid in deciding whether to close the ventricular septal defect in patients undergoing one-stage unifocalization. Methods: Between July 1992 and April 1996, 27 infants with pulmonary atresia, ventricular septal defect, and aortopulmonary collaterals were treated at our institution. Midline complete unifocalization was performed in 25 patients—the ventricular septal defect was closed in 17 and left open in eight. Two patients with severe distal collateral stenoses underwent staged unifocalization. Pulmonary artery and collateral sizes were measured from preoperative angiograms and used to calculate the indexed cross-sectional area of the total neopulmonary artery bed. An intraoperative pulmonary flow study previously validated with experiments in neonatal lambs was performed in six patients: the unifocalized neopulmonary arteries were perfused with a known flow and pulmonary artery pressures were recorded. Results: The neopulmonary artery index was greater in patients who underwent ventricular septal defect closure than in those who did not ( p = 0.001), although the values did overlap. This index correlated with the postoperative right ventricular/left ventricular pressure ratio ( p = 0.037). Mean pulmonary artery pressures obtained during the intraoperative flow study and after bypass were comparable. Conclusion: The total neopulmonary artery index correlates with postrepair right ventricular/left ventricular pressure ratio and is useful in deciding when to close the ventricular septal defect if it is larger than 200 mm 2/m 2. The pulmonary flow study is helpful in deciding whether to close the ventricular septal defect in all patients. (J Thorac Cardiovasc Surg 1997;113:858-68)