Sunjay Kaushal

Characterization and Functionality of Cardiac Progenitor Cells in Congenital Heart Patients

Background— Human cardiac progenitor cells (hCPCs) may promote myocardial regeneration in adult ischemic myocardium. The regenerative capacity of hCPCs in young patients with nonischemic congenital heart defects for potential use in congenital heart defect repair warrants exploration. Methods and Results— Human right atrial specimens were obtained during routine congenital cardiac surgery across 3 groups: neonates (age, <30 days), infants (age, 1 month to 2 years), and children (age, >2 to ≤13 years). C-kit+ hCPCs were 3-fold higher in neonates than in children >2 years of age. hCPC proliferation was greatest during the neonatal period as evidenced by c-kit+ Ki67+ expression but decreased with age. hCPC differentiation capacity was also greatest in neonatal right atrium as evidenced by c-kit+, NKX2–5+, NOTCH1+, and NUMB+ expression. Despite the age-dependent decline in resident hCPCs, we isolated and expanded right atrium–derived CPCs from all patients (n=103) across all ages and diagnoses using the cardiosphere method. Intact cardiospheres contained a mix of heart-derived cell subpopulations that included cardiac progenitor cells expressing c-kit+, Islet-1, and supporting cells. The number of c-kit+–expressing cells was highest in human cardiosphere-derived cells (hCDCs) grown from neonatal and infant right atrium. Furthermore, hCDCs could differentiate into diverse cardiovascular lineages by in vitro differentiation assays. Transplanted hCDCs promoted greater myocardial regeneration and functional improvement in infarcted myocardium than transplanted cardiac fibroblasts. Conclusions— Resident hCPCs are most abundant in the neonatal period and rapidly decrease over time. hCDCs can be reproducibly isolated and expanded from young human myocardial samples regardless of age or diagnosis. hCPCs are functional and have potential in congenital cardiac repair.

A Strong Regenerative Ability of Cardiac Stem Cells Derived From Neonatal Hearts

Background— Human cardiac stem cells (CSCs) promote myocardial regeneration in adult ischemic myocardium. The regenerative capacity of CSCs in very young patients with nonischemic congenital heart defects has not been explored. We hypothesized that isolated neonatal-derived CSCs may have a higher regenerative ability than adult-derived CSCs and might address the structural deficiencies of congenital heart disease. Methods and Results— Human specimens were obtained during routine cardiac surgical procedures from right atrial appendage tissue discarded from 2 age groups: neonates and adults patients. We developed a reproducible isolation method that generated cardiosphere-derived cells (CDCs), regardless of starting tissue weight or age. Neonatal-derived CDCs demonstrated increased number of cardiac progenitor cells expressing c-kit+, flk-1, and Islet-1 by flow cytometry and immunofluorescence. When transplanted into infarcted myocardium, neonatal-derived CDCs had a significantly higher ability to preserve myocardial function, prevent adverse remodeling, and enhance blood vessel preservation and/or formation when compared with adult-derived CDCs. Last, neonatal-derived CDCs were more cardiomyogenic than adult-derived CDCs when cocultured with neonatal cardiomyocytes and displayed enhanced angiogenic function compared with adult-derived CDCs. Conclusions— Neonatal-derived CDCs have a strong regenerative ability when compared with adult-derived CDCs that may depend on angiogenic cytokines and an increase prevalence of stem cells. This has important implications in the potential use of CDCs in future clinical trials.

Coarctation of the Aorta: Midterm Outcomes of Resection With Extended End-to-End Anastomosis

BACKGROUND We began using the technique of resection with extended end-to-end anastomosis for infants and children with coarctation of the aorta in 1991. The purpose of this review is to evaluate the midterm outcomes of this technique, specifically determining the incidence of and risk factors for transcatheter or surgical reintervention. METHODS A retrospective analysis of the cardiac surgery database was performed to identify all patients who had a diagnosis of coarctation of the aorta with or without ventricular septal defect and had resection with extended end-to-end anastomosis from 1991 to 2007. Perioperative course and follow-up with physical examination, echocardiogram, and cardiology evaluation were obtained. RESULTS From 1991 through 2007, 201 patients had repair of coarctation of the aorta with resection with extended end-to-end anastomosis. The median age was 23 days, and the median weight was 4.0 kg. Surgical approach was by left thoracotomy in 157 patients (78%) with a mean cross-clamp time of 18 +/- 4 minutes. Median sternotomy approach was used in 44 patients (22%) to repair a hypoplastic transverse aortic arch (n = 16) or because of associated ventricular septal defect (n = 28) with a mean circulatory arrest time of 14 +/- 9 minutes. Early mortality occurred in 4 patients (2.0%). Three patients (1.5%) required early arch revision: 2 intraoperatively and 1 on postoperative day 1. Follow-up data were available for 182 patients (91%) with a mean follow-up of 5.0 +/- 4.3 years (908 patient-years). Reinterventions (n = 8; 4.0%) included three balloon angioplasties and five reoperations; 75% of the reinterventions occurred in the first postoperative year. Hypoplastic transverse aortic arch was not a risk factor for reintervention (p = 0.36), but was a risk factor for mortality (p = 0.039). Aberrant right subclavian artery was the only risk factor for recoarctation (p = 0.007). CONCLUSIONS Repair of coarctation of the aorta with resection with extended end-to-end anastomosis has a low early mortality, effectively addresses transverse arch hypoplasia, and at midterm follow-up has a low rate of reintervention for recurrent coarctation.

Total anomalous pulmonary venous connection: Results of surgical repair of 100 patients at a single institution

OBJECTIVE Surgical repair of total anomalous pulmonary venous connection is associated with significant mortality and morbidity, especially in patients with single-ventricle physiology. This study analyzes total anomalous pulmonary venous connection surgical repair results at one institution to identify trends and indicators of positive outcome. METHODS Our cardiac surgery database identified 100 patients undergoing surgical repair of total anomalous pulmonary venous connection (1990-2008): supracardiac (52), cardiac (15), infracardiac (23), and mixed (10). The median age at repair was 14.6 days (range, 0-4 years), and the median weight was 3.5 kg (range, 1.3-15 kg). Patients were divided into 2 groups: biventricular (n = 83) or single-ventricle (n = 17) physiology. All but 1 of the patients with single-ventricle physiology had heterotaxy syndrome (94%), and 13 of 17 patients had supracardiac anatomy. RESULTS There were 12 operative deaths (4 in the biventricular group [5%] and 8 in the single-ventricle group [47%], P < .01) and 9 late deaths (6 in the biventricular group [7%] and 3 in the single-ventricle group [18%], P < .05). Death by total anomalous pulmonary venous connection type was supracardiac (12/52; 23.1%), cardiac (1/15; 6.7%), infracardiac (3/23; 13.0%), and mixed (5/10; 50%). Pulmonary venous obstruction was present in 22 patients in the biventricular group (27%) and in 7 patients in the single-ventricle group (41%; P = .25). Mortality was 9 of 29 (31%) in those with pulmonary venous obstruction and 12 of 71 (17%) in those with nonpulmonary venous obstruction (P = .23). Deep hypothermic circulatory arrest was used in 38 patients (27 in the biventricular group, 32.5%; 11 in the single-ventricle group, 64.7%). Mean deep hypothermic circulatory arrest time was 31.4 +/- 10.7 minutes (P = not significant between groups). Median postoperative length of stay was 11 days (range, 0-281 days). Nineteen patients required reoperation for pulmonary venous stenosis (14 in the biventricular group and 5 in the single-ventricle group. P = .045); the median time to reoperation was 104 days (range, 4-753 days). CONCLUSION Patients with total anomalous pulmonary venous connection with biventricular anatomy have good outcomes. Patients with single-ventricle anatomy have higher mortality and increased risk for pulmonary vein stenosis requiring reoperation. Mortality is highest in patients with mixed-type total anomalous pulmonary venous connection.

Intramural Coronary Length Correlates With Symptoms in Patients With Anomalous Aortic Origin of the Coronary Artery

BACKGROUND Anomalous aortic origin of a coronary artery (AAOCA) from the opposite sinus of Valsalva is a rare congenital anomaly with the potential for myocardial ischemia and sudden death. This review evaluated our series of AAOCA patients, who underwent coronary artery unroofing, to test our hypothesis that the intramural length of the anomalous coronary artery correlates with symptoms. METHODS A retrospective analysis of symptoms, preoperative imaging (computed tomography and magnetic resonance imaging), intraoperative assessment, perioperative course, and follow-up were reviewed. RESULTS From 2005 to 2010, 27 patients (70% male) underwent surgical AAOCA repair. Mean age was 14.3±12 (range, 6 to 52) years. In 25 patients with right AAOCA, 14 had chest pain and 4 had syncope. Both patients with left AAOCA had chest pain. AAOCA unroofing was done in 25 and side-to-side anastomosis in 2. The intramural coronary artery length measured intraoperatively correlated with preoperative symptoms (symptoms=10±3.58 mm, no symptoms=5.2±1.5 mm, p<.002), as did preoperative imaging measurements (symptoms=7.8±2.8 mm, no symptoms=5.3±0.8 mm, p<.001). Preoperative imaging strongly predicted the intraoperative measurement (r=0.81, p=0.00001). There were no deaths, significant morbidity, or recurrence of symptoms. CONCLUSIONS Coronary unroofing for AAOCA is a safe method of enlarging the coronary orifice and eliminating the intramural course. Symptomatic patients had a longer intramural course than asymptomatic patients, as assessed by preoperative imaging and intraoperative measurements. These results may have important clinical implications in determining indications for operation.

Tracheal reconstruction in children with unilateral lung agenesis or severe hypoplasia.

BACKGROUND Infants with congenital tracheal stenosis may also have unilateral lung agenesis or severe lung hypoplasia. The purpose of this review is to evaluate our results with these patients and compare their presentations and outcomes to those of tracheal stenosis patients with two lungs. METHODS Our database was queried for patients undergoing tracheal stenosis repair since 1982. Patients were divided into two groups based on pulmonary anatomy of single lung (SL = unilateral lung agenesis or severe hypoplasia) or two lungs (BL = bilateral lungs) and analyzed to compare presentation and outcomes. RESULTS From 1982 to 2008, 71 patients had tracheal stenosis repair. Bilateral lungs were present in 60 patients; 9 patients had an absent (4) or severely hypoplastic (5) right lung, and 2 patients had an absent left lung (SL = 11). Age at repair was similar between groups; median age 0.42 years in the SL group (mean 0.80 +/- 1.0 years) versus 0.37 years in the BL group (mean 0.91 +/- 2.1 years, p = not significant [ns]). In the SL group 8 of 11 (73%) were intubated preoperatively versus 15 of 60 (25%) in the BL group (p = 0.004). In the SL group 4 of 11 (36%) patients had pulmonary artery sling versus 20 of 60 (33%) of BL patients (p = ns). In the SL group 2 of 11 (18%) versus 14 of 60 (23%) in the BL group had intracardiac anomalies requiring simultaneous repair (p = ns). Procedures included pericardial tracheoplasty (2 vs 26), tracheal autograft (4 vs 16), slide tracheoplasty (3 vs 8), and tracheal resection (2 vs 10). Overall mortality (operative and late) was 2 of 11 (18%) SL versus 10 of 60 (17%) BL (p = ns). Median postoperative length of stay was 43 days SL (mean 48.6 +/- 40) versus 30 days BL (mean 52.2 +/- 65) (p = ns). The incidence of postoperative tracheostomy (SL group) was 0 of 3 for slide tracheoplasty and 5 of 8 for the other techniques (p = 0.12). CONCLUSIONS Despite the increased severity of pathology and increased critical presentation of tracheal stenosis patients with unilateral lung agenesis or severe hypoplasia, outcome measures of mortality and length of stay were similar to patients with two lungs. The incidence of associated pulmonary artery sling (1 of 3) and intracardiac anomalies (1 of 4) was similar. Unilateral lung agenesis or severe hypoplasia should not preclude operative repair of tracheal stenosis. Slide tracheoplasty is our current procedure of choice for these infants.

A Deep Proteome Analysis Identifies the Complete Secretome as the Functional Unit of Human Cardiac Progenitor Cells.

Rationale: Cardiac progenitor cells are an attractive cell type for tissue regeneration, but their mechanism for myocardial remodeling is still unclear. Objective: This investigation determines how chronological age influences the phenotypic characteristics and the secretome of human cardiac progenitor cells (CPCs), and their potential to recover injured myocardium. Methods and Results: Adult (aCPCs) and neonatal (nCPCs) cells were derived from patients aged >40 years or <1 month, respectively, and their functional potential was determined in a rodent myocardial infarction model. A more robust in vitro proliferative capacity of nCPCs, compared with aCPCs, correlated with significantly greater myocardial recovery mediated by nCPCs in vivo. Strikingly, a single injection of nCPC-derived total conditioned media was significantly more effective than nCPCs, aCPC-derived TCM, or nCPC-derived exosomes in recovering cardiac function, stimulating neovascularization, and promoting myocardial remodeling. High-resolution accurate mass spectrometry with reverse phase liquid chromatography fractionation and mass spectrometry was used to identify proteins in the secretome of aCPCs and nCPCs, and the literature-based networking software identified specific pathways affected by the secretome of CPCs in the setting of myocardial infarction. Examining the TCM, we quantified changes in the expression pattern of 804 proteins in nCPC-derived TCM and 513 proteins in aCPC-derived TCM. The literature-based proteomic network analysis identified that 46 and 6 canonical signaling pathways were significantly targeted by nCPC-derived TCM and aCPC-derived TCM, respectively. One leading candidate pathway is heat-shock factor-1, potentially affecting 8 identified pathways for nCPC-derived TCM but none for aCPC-derived TCM. To validate this prediction, we demonstrated that the modulation of heat-shock factor-1 by knockdown in nCPCs or overexpression in aCPCs significantly altered the quality of their secretome. Conclusions: A deep proteomic analysis revealed both detailed and global mechanisms underlying the chronological age-based differences in the ability of CPCs to promote myocardial recovery via the components of their secretome.

The Arterial Switch Operation: 25-Year Experience With 258 Patients

BACKGROUND At our institution, the arterial switch operation for transposition of the great arteries has transitioned from the Gore-Tex patch (W.L. Gore & Associates, Flagstaff, AZ) for pulmonary artery reconstruction to redundant pantaloon pericardial patch (RPPP). The (U-shaped) coronary artery button was used for coronary reimplantation. This study investigates overall mortality and factors for neopulmonary artery, neoaortic, and coronary artery surgical reintervention. METHODS We performed a retrospective chart review of all patients who underwent arterial switch between 1983 and 2007. Our surgical database, operative reports, and cardiology clinic charts were reviewed. Time to event was plotted as Kaplan-Meier curves. Predictors of time-to-event were examined using Cox proportional hazard modeling. RESULTS A total of 258 patients underwent arterial switch during the study. Mortality declined from 15% (era I: 1983 to 1990) to 11% (era II: 1991 to 1998) to 7% (era III: 1999 to 2007). Era III had a significantly later time to death compared with era I (hazard ratio [HR] 0.62, p = 0.04). The RPPP had a lower neopulmonary artery reintervention rate compared with Gore-Tex; 9 of 225 (4%) versus 3 of 21 (14%), p = 0.008. Complex anatomy increased risk for neopulmonary reintervention (HR 3.3, p = 0.03). Surgical reintervention rate for coronary arteries was 2%. Complex coronary anatomy (HR 17.9, p = 0.01) predicted coronary reintervention. Predictors of neoaortic reintervention were prior pulmonary artery band (HR 4.3, p = 0.03), complex anatomy (HR 3.5, p = 0.01), and coronary artery anatomy (HR 3.5, p = 0.04). CONCLUSIONS Arterial switch operation mortality has decreased. Conversion to RPPP reduced neopulmonary artery reintervention. The (U-shaped) coronary artery button technique is associated with low coronary reintervention rates. Complex coronary anatomy increases coronary and aortic reintervention. Prior pulmonary artery banding and complex anatomy increase aortic reintervention.

Extracardiac Versus Intra-Atrial Lateral Tunnel Fontan: Extracardiac is Better

This article was prepared to summarize the points made in a debate that the first author (C.L.B.) had with Dr. Richard Jonas at the American Association for Thoracic Surgery 90th Annual Meeting. The topic of the debate was the optimal surgical approach for functional single-ventricle patients: extracardiac versus intra-atrial lateral tunnel Fontan. My role was to take the viewpoint that the extracardiac Fontan is better. This review summarizes our results at Childrens Memorial Hospital (Chicago, IL) with 180 patients undergoing a primary Fontan procedure and 126 patients undergoing an extracardiac Fontan as part of a Fontan conversion. The world literature was reviewed on outcomes following the Fontan procedure, focusing on six main areas supporting the superiority of the extracardiac Fontan: hemodynamics, arrhythmias, applicability to complex anatomy, use of cardiopulmonary bypass, complications of fenestration and thromboembolism, and operative mortality. Based on this review, it is our conclusion that the extracardiac Fontan is the procedure of choice for patients with a functional single ventricle based on a very low operative mortality, a lower incidence of early and late arrhythmias, improved hemodynamics, fewer postoperative complications, and applicability to a wide variety of complex cardiac anatomy.

Use of human embryonic stem cell derived-mesenchymal cells for cardiac repair.

Human mesenchymal stem cells (hMSC) have proven beneficial in the repair and preservation of infarcted myocardium. Unfortunately, MSCs represent a small portion of the bone marrow and require ex vivo expansion. To further advance the clinical usefulness of cellular cardiomyoplasty, derivation of “MSC‐like” cells that can be made available “off‐the‐shelf” are desirable. Recently, human embryonic stem cell‐derived mesenchymal cells (hESC‐MC) were described. We investigated the efficacy of hESC‐MC for cardiac repair after myocardial infarction (MI) compared to hMSC. Because of increased efficacy of cell delivery, cells were embedded into collagen patches and delivered to infarcted myocardium. Culture of hMSC and hESC‐MCs in collagen patches did not induce differentiation or significant loss in viability. Transplantation of hMSC and hES‐MC patches onto infarcted myocardium of athymic nude rats prevented adverse changes in infarct wall thickness and fractional area change compared to a non‐viable patch control. Hemodynamic assessment showed that hMSCs and hES‐MC patch application improved end diastolic pressure equivalently. There were no changes in systolic function. hES‐MC and hMSC construct application enhanced neovessel formation compared to a non‐viable control, and each cell type had similar efficacy in stimulating endothelial cell growth in vitro. In summary, the use of hES‐MC provides similar efficacy for cellular cardiomyoplasty as compared to hMSC and may be considered a suitable alternative for cell therapy. Biotechnol. Bioeng. 2012;109: 274–283.