Muhammad S. Khan

Surgical pulmonary valve replacement: a benchmark for outcomes comparisons.

BACKGROUNDnPatients with right heart obstructive lesions develop residual or recurrent right ventricle outflow tract pathology as a result of native or implanted pulmonary valve (PV) dysfunction. Until recently, the standard of care has been surgical placement of a PV or valved right ventricle to pulmonary artery conduit. Catheter-based options are being increasingly applied in patients with PV dysfunction. The purpose of our study was to evaluate outcomes of surgical pulmonary valve/conduit replacement (PVR) at a large pediatric hospital to provide contemporary benchmark data for comparison with developing technologies.nnnMETHODSnRetrospective review of patients undergoing PVR not associated with complex concomitant procedures from July 1995 to December 2010 was completed. Inclusion criteria were designed to generally match those applied to patients promoted for catheter-based valve replacement based on age and weight (age≥5 years and weight≥30 kg).nnnRESULTSnThere were 148 PVRs with all patients having undergone ≥1 previous interventions (tetralogy of Fallot [53%] and pulmonary atresia [17%]). Surgical indications were PV insufficiency (60%), PV stenosis (26%), and both (13%). Valves used included bioprosthetic (n=108; 73%) and homografts (n=40; 27%). Time-to-extubation, intensive care unit stay, and hospital length of stay were <1 day (interquartile range, 0-1 day), 2 days (interquartile range, 1-2 days), and 5 days (interquartile range, 4-6 days), respectively, with no hospital deaths. Freedom from PV reintervention at 1, 3, and 5 years was 99%, 99%, and 94%, respectively. Multivariable analysis showed age<13 years (P=.003), and smaller valve size (P=.025) were associated with increased risk of valve reintervention. Patient survival at follow-up (mean, 5.0±3.9 years) was 99%.nnnCONCLUSIONSnSurgical PVR is safe with low in-hospital and midterm follow-up mortality and reoperation rates. These outcomes provide a useful benchmark for treatment strategy comparisons.

The Blalock-Taussig Shunt Revisited: A Contemporary Experience

BACKGROUNDnThe Blalock-Taussig shunt (BTS) was introduced 68 years ago before open repair of cyanotic congenital heart disease (CHD) was possible. The originally described technique has undergone many modifications but remains an integral component of the management of cyanotic CHD. We report our contemporary, single institution experience with the BTS.nnnSTUDY DESIGNnWe performed a retrospective review of all patients treated with a BTS from June 1995 to December 2011.nnnRESULTSnThere were 730 BTS performed in 712 patients; 727 (99.6%) by interposition graft (modified). The BTS was predominantly right-sided (n = 657, 90%). Median age and weight at palliation were 8 days (range 0 days to 18.5 years) and 3.2 kg (1.5 to 51 kg). Median hospital length of stay was 16 days (range 0 to 347 days). There were 241 (33%) BTS performed as initial palliation for ultimate 2-ventricle (2V) circulation, 471 (65%) as part of staged palliation for patients with functionally univentricular lesions (1V), 6 (1%) as a part of 1.5-ventricle palliation, and 12 (1%) for Ebsteins anomaly. There were 473 (65%) BTS placed via sternotomy and the most common site of BTS was the right subclavian to right pulmonary artery (PA; n = 452, 62%). Hospital mortality was higher for BTS in 1V patients (1V 15% vs 2V 3%, p < 0.0001). Overall, 536 (73%) patients were bridged to complete repair or the second stage of 1V palliation after a median duration of 6.5 months (0 days to 15.3 years). Multivariable regression showed that sternotomy approach, use of cardiopulmonary bypass, innominate artery-PA shunt, and diagnosis of Ebsteins were risk factors for in-hospital mortality (p < 0.05).nnnCONCLUSIONSnAlthough the BTS remains an important component of the surgical treatment of cyanotic congenital heart disease, patients with single ventricle circulation still face significant ongoing risk of mortality.

Is lung transplantation survival better in infants? Analysis of over 80 infants

BACKGROUNDnThere have been >1,600 pediatric lung transplantations (LTx) performed worldwide with a trend toward improved outcomes over the last 25 years. The majority of these LTxs have been in older children and adolescents. Less than 4 infant (defined as ≤ 12 months of age) LTxs per year have been performed over the past 20 years, mostly in the USA. However, infant LTx outcomes have not been well documented in a multi-institutional longitudinal fashion.nnnMETHODSnThe United Network of Organ Sharing database was queried from October 1987 to July 2011. Of the 1,003 pediatric LTxs reported, 84 (8%) were infants. All combined transplantations were excluded.nnnRESULTSnEighty-one infants received 84 LTxs, of which 95% had a bilateral LTx. Median age and weight at LTx was 4 months (range 0 to 11 months) and 5.3 kg (2.7 to 11.8 kg), respectively. Median ischemic time was 5.2 hours (2.0 to 10.8 hours). Overall Kaplan-Meier graft survival was similar for infants compared with other pediatric age group (OPA: >1 to 18 years) LTx recipients (half-life 4.0 years vs 3.4 years, p = 0.7). Conditional 1-year graft survival for infants was significantly higher than OPA (half-life 7.4 years vs 5.0 years, p = 0.024). Early (1987 to 2000, n = 46) and late (2001 to 2011, n = 38) era graft survival was not significantly different. Graft survival in pre-LTx ventilated infants was significantly better than pre-LTx ventilated OPA (half-life 6.1 years vs 0.9 year, p = 0.004) and was not statistically different from pre-LTx infants not on ventilatory support (half-life 6.1 years vs 2.2 years, p = 0.152). Cox regression of 5 variables (weight, donor arterial PO(2), pre-Tx ventilator, organ ischemic time, center experience) showed that survival was associated with increased center experience (p = 0.03).nnnCONCLUSIONnInfants undergoing LTx have outcomes similar to those of all other pediatric LTx patients.

Infectious Complications and Outcomes in Children Supported with Left Ventricular Assist Devices

BACKGROUNDnInfectious complications constitute a major cause of morbidity and death in adult patients supported with left ventricular assist devices (VADs). The incidence and patient outcomes related to infectious complications in pediatric patients on VAD support remain largely unknown. The aim of this study was to determine the incidence of infection among pediatric VAD recipients and to characterize the microbiology, associated risk factors, and clinical outcome.nnnMETHODSnWe conducted a retrospective record review of all patients undergoing VAD support for ≥2 weeks at Texas Childrens Hospital from June 1999 to December 2011. Infections were categorized as VAD-specific, VAD-related, or non-VAD-related using the International Society for Heart and Lung Transplantation (ISHLT) definitions for VAD infections.nnnRESULTSnFifty-two VADs were implanted in 51 patients; of these, 35 patients (69%) had 92 infections while receiving VAD support. These included 10 VAD-specific infections, 23 VAD-related infections, and 59 non-VAD infections. The overall rate of VAD infections (specific + related) was 8/1,000 days of VAD support. The most common pathogens were Staphylococcus aureus, coagulase-negative staphylococci, Pseudomonas aeruginosa, and Candida spp. Of 8 deaths that occurred during VAD support, 3 (37.5%) were directly related to infections. Continuous-flow VAD (p = 0.0427) and prior cardiac transplantation with rejection (p = 0.0191) were significantly associated with development of VAD infections.nnnCONCLUSIONSnInfectious complications are common in pediatric patients undergoing VAD support. VAD infections do not prevent successful cardiac transplantation in children.

Implantation of Total Artificial Heart in Congenital Heart Disease

In patients with end-stage heart failure (HF), a total artificial heart (TAH) may be implanted as a bridge to cardiac transplant. However, in congenital heart disease (CHD), the malformed heart presents a challenge to TAH implantation. In the case presented here, a 17 year-old patient with congenital transposition of the great arteries (CCTGA) experienced progressively worsening HF due to his congenital condition. He was hospitalized multiple times and received an implantable cardioverter defibrillator (ICD). However, his condition soon deteriorated to end-stage HF with multisystem organ failure. Due to the patients grave clinical condition and the presence of complex cardiac lesions, the decision was made to proceed with a TAH. The abnormal arrangement of the patients ventricles and great arteries required modifications to the TAH during implantation. With the TAH in place, the patient was able to return home and regain strength and physical well-being while awaiting a donor heart. He was successfully bridged to heart transplantation 5 months after receiving the device. This report highlights the TAH is feasible even in patients with structurally abnormal hearts, with technical modification.

Is mechanically bridging patients with a failing cardiac graft to retransplantation an effective therapy? Analysis of the United Network of Organ Sharing database.

BACKGROUNDnThe results of bridging patients with cardiac allograft failure to retransplantation (ReTx) with mechanical circulatory support (MCS) have not been well studied. The United Network of Organ Sharing (UNOS) database was used to analyze outcomes of patients successfully bridged with MCS to cardiac ReTx.nnnMETHODSnOf 1,690 cardiac ReTx identified in the UNOS database from October 1987 to July 2011, 149 (8.8%) were bridged to ReTx with MCS.nnnRESULTSnPatients bridged to ReTx with MCS had a poorer survival than patients not bridged (p < 0.0001). ReTx after ventricular assist device (VAD) support had better survival than ReTx after extracorporeal membrane oxygenation (ECMO; half-life, 3.9 years vs 61 days, p = 0.026). For patients bridged to ReTx, graft survival was 40% for ReTx within 1 year of primary Tx vs 64% (p = 0.003). When ReTx was performed 1 year after cardiac Tx, survival was similar in patients bridged with a VAD and those not bridged (mean, 7.5 vs 8.7 years; p = 0.8). Survival for patients bridged to ReTx with ECMO was consistently worse (p ≤ 0.05) in all analyses. The 1-year survival of ReTx after VAD performed in 2003 to 2011 (67%) was better than in the earlier era of 1987 to 2002 (37%, p = 0.005).nnnCONCLUSIONSnBridging patients to ReTx with ECMO at any time is not advisable. Bridging patients with MCS to ReTx within 1 year of primary cardiac Tx is not advisable. Survival after ReTx for patients bridged by VAD has improved considerably over time. Patients who survive the first year after cardiac Tx can be bridged by VAD to ReTx with an expectation that outcomes can be similar to ReTx patients who did not require MCS.

Does donor arterial partial pressure of oxygen affect outcomes after lung transplantation? A review of more than 12,000 lung transplants

INTRODUCTIONnIn lung transplantation (LTx), the arterial partial pressure of oxygen (PaO(2)) is traditionally regarded as critical information for assessment of donor lung function. Each center sets its own thresholds; by convention, a donor PaO(2) of less than 300 mm Hg has been considered disqualifying. Limited literature exists to support such a practice. We analyzed all LTxs performed in the United States over a 9-year period to assess the effect of donor PaO(2) on graft survival.nnnMETHODSnThe United Network for Organ Sharing (UNOS) database was queried for LTx (January 2000-November 2009). Of 12,545 LTx performed, 12,045 (96%) had donor PaO(2) data on a fraction of inspired oxygen of 1.0, recorded at the time of procurement.nnnRESULTSnMean donor PaO(2) was 407 ± 140 mm Hg. The majority of LTxs had a donor PaO(2) greater than 300 mm Hg (9593 (80%]) whereas PaO(2) was 200 mm Hg or less in 1830 (15%) and 201 to 300 in 582 (5%) donors. Use of donors with a PaO(2) of less than 200 increased over time from 5% (45) in 2000 to 21% (295) in 2009 (P = .002). Kaplan-Meier survival analysis showed no difference in graft survival with differing donor PaO(2)s, irrespective of whether patients had a single or double LTx. A Cox multivariable analysis of 21 donor characteristics demonstrated that donor PaO(2) had no association with graft survival.nnnCONCLUSIONSnDonor PaO(2) levels did not affect graft survival. The use of donors with lower PaO(2)s could substantially increase the donor pool. We are not suggesting that donor PaO(2) is not important when assessing potential lung donors but its level of importance in regard to other criteria appears less than previously believed.

Outcomes of Anomalous Left Coronary Artery From Pulmonary Artery Repair: Beyond Normal Function

BACKGROUNDnAnomalous left coronary artery from pulmonary artery (ALCAPA) is associated with high mortality if left uncorrected. We describe long-term outcomes after surgical repair and ventricular function changes on long-term follow-up.nnnMETHODSnA retrospective review of patients who had ALCAPA repair from January 1996 to December 2011 was completed. Ventricular function was assessed by shortening fraction and ejection fraction, left ventricular end-diastolic dimension, and severity of mitral regurgitation. Speckle tracking echocardiography served as a marker of early myocardial dysfunction.nnnRESULTSnIn total, 34 patients underwent ALCAPA repair at median age of 5 months (range, 3 days to 39 years). Surgical interventions included coronary translocation in 31 patients (91%), Takeuchi repair in 2 (6%), and coronary ligation in 1 patient (3%). Concomitant mitral valve repair was performed in 5 patients (15%). No patient required mechanical circulatory support postoperatively. There was no early mortality. At median follow-up of 6 years (range, 1 month to 14 years), there were 5 reoperations: 2 heart transplants (6%), 1xa0mitral valve replacement (3%), 1 coronary artery bypass graft (3%), and 1 ventricular septal defect closure (3%); there was 1 death 2 years after surgery. Ejection fraction improved from 21% ± 6% to 60% ± 7% (pxa0= 0.008), mean shortening fraction from 25% ± 14% to 38% ± 5% (pxa0= 0.01), mean left ventricular end-diastolic dimension Z-score from 6.0 ± 3.8 to 0.9 ± 0.7 (p < 0.001), and number of patients with moderate-severe mitral regurgitation from 44% (15 of 34) to 5% (1 of 21). All patients had normal ejection fraction and shortening fraction at last follow-up. Speckle tracking echocardiography showed decreased global longitudinal (pxa0= 0.01) and circumferential strain (pxa0= 0.03) for 11 of 14 patients (79%).nnnCONCLUSIONSnExcellent outcomes are achieved with repair of ALCAPA without mechanical circulatory support and with low reintervention rates. Normal ejection fraction and shortening fraction do not accurately convey myocardial dysfunction in these patients.

Pediatric ventricular assist device use as a bridge to transplantation does not affect long-term quality of life.

OBJECTIVEnThe present study sought to determine the long-term quality of life (QOL) of children who required long-term ventricular assist device (VAD) support as a bridge to transplantation (BTT) compared with children who underwent heart transplantation without VAD support. Currently, 20% of children undergoing heart transplantation have required a VAD as a BTT. Few data have been published assessing how children requiring a VAD as a BTT will fair in terms of their long-term QOL.nnnMETHODSnThe present study used a cross-sectional design, using the Core and Cardiac modules of the Pediatric Quality of Life Inventory survey. In a secondary analysis, the factors associated with worse QOL outcomes among the VAD patients were also investigated.nnnRESULTSnAt follow-up (median, 4.2 years), between the 21 children who required a VAD as a BTT and 42 who went straight to transplantation, no significant differences were found in the QOL as measured using the Psychosocial Health Summary Score, Physical Health Summary Score, or Total Score in the surveys Core Module, nor were any differences found in the outcomes assessed using the surveys Cardiac Module. Of the patients who required a VAD, only the presence of a neurologic complication was associated with worse QOL, which was demonstrated by decreased Physical Health Summary and Cardiac Communication scores.nnnCONCLUSIONSnOver the long term, surviving children who required a long-term VAD as a BTT experience a similar QOL as those who went straight to transplantation.

Early surgical therapy of infective endocarditis in children: A 15-year experience

OBJECTIVESnInfective endocarditis is rare in children but potentially carries high mortality and morbidity. Few data exist regarding surgical therapy and the associated outcomes in children with infective endocarditis. The aim of the present study was to describe the characteristics and outcomes of children undergoing surgery for infective endocarditis.nnnMETHODSnA retrospective review of all patients aged 21 years or younger diagnosed with definitive infective endocarditis at a single center from 1996 to 2010 was performed.nnnRESULTSnOf 76 identified patients with infective endocarditis (median age, 8.3 years; 73.9% boys), 46 patients (61%) required surgical intervention. Staphylococcus aureus was most commonly isolated (18 patients, 24%) followed by Streptococcus (17 patients, 22%). Common surgical indications included severe valvular insufficiency in 13 patients, septic embolization in 12, concomitant severe valvular insufficiency and ventricular dysfunction in 9, persistent vegetations in 9, and persistent bacteremia in 3. Although early surgery was performed within 7 days of diagnosis in 35 patients (76%), 25 (54%) underwent surgery within 3 days or less. The factors associated with surgery included the presence of ventricular dysfunction, left-sided vegetation, severe valvular insufficiency, septic embolization, and S aureus. Surgery within 3 days or less was associated with the presence of ventricular dysfunction and S aureus. Native valve repair was performed in 50% of patients with native-valve disease. Postoperatively, no septic embolization events occurred and recurrence was low (2%). The 1-, 5-, and 10-year survival was 98% ± 2%, 90% ± 8%, and 81% ± 11%, respectively.nnnCONCLUSIONSnChildren with infective endocarditis can undergo successful early surgical therapy with a low risk of septic embolization, recurrence, and operative mortality.