Varsha M. Bandisode

Does a ventriculotomy have deleterious effects following palliation in the Norwood procedure using a shunt placed from the right ventricle to the pulmonary arteries

INTRODUCTION A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy. METHODS We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation. RESULTS At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries. CONCLUSIONS Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.

Usefulness of Live Three-Dimensional Transesophageal Echocardiography in a Congenital Heart Disease Center

Three-dimensional (3D) transesophageal echocardiography (TEE) has numerous potential applications in the care of patients with congenital heart disease (CHD). However, there were few data examining its utility in this setting. The aim was to describe the initial experience and feasibility of this modality at a tertiary CHD center. Twenty-seven 3D-TEE studies using the x7-2t live 3D matrix TEE transducer with an iE33 echocardiographic scanner (Philips Medical Systems, Bothell, Washington) were attempted. The utility of this method was examined in the 3 settings of interventional catheterizations (n = 16), intraoperative studies (n = 4), and diagnostic studies (n = 7). The probe was successfully inserted in 26 of 27 patients (weight 22.6 to 110 kg). In conclusion, the current matrix-array 3D-TEE probe was found to have a wide variety of clinical applications in a CHD center.

Comparison of Norwood Shunt Types: Do the Outcomes Differ 6 Years Later?

BACKGROUND A modification to the Norwood procedure involving a right ventricle-to-pulmonary artery (RV-PA) shunt may improve early postoperative outcomes. Concerns remain about the effect of the right ventriculotomy required with this shunt on long-term ventricular function. METHODS Between January 2000 and April 2005, 76 patients underwent the Norwood procedure, 35 with a modified Blalock-Taussig shunt (mBTS) and 41 with a RV-PA shunt. Patients were monitored until death or September 1, 2009, with an average follow-up of 6.8 years. Cardiac catheterization, echocardiograms, perioperative Fontan courses, and need for cardiac transplantation were compared between groups. RESULTS Cumulative survival was 63% (22 of 35) in the mBTS group vs 78% (32 of 41) in the RV-PA group (p = 0.14). Pre-Fontan echocardiography revealed poorer ventricular function in RV-PA patients (p = 0.03). Cardiac transplantation was required in 6 of 32 (19%) patients with a prior RV-PA shunt vs 1 of 23 (4%) in the mBTS group (p = 0.06). This results in an almost identical cumulative transplant-free survival between groups; 60% (21 of 35) in the mBTS group and 63% (26 of 41) in the RV-PA group (p = 0.95). CONCLUSIONS Neither shunt offers a clear survival advantage through an average follow-up of 6.8 years. The RV-PA shunt results in impaired late ventricular function that may result in an increased need for cardiac transplantation.

Early Experience with Real-Time Three-Dimensional Echocardiographic Guidance of Right Ventricular Biopsy in Children

Background: Right ventricular endomyocardial biopsy is the gold standard for detecting active myocardial inflammation in cardiomyopathy as well as rejection after cardiac transplantation. This procedure has historically required the exclusive use of fluoroscopic guidance to guide catheter, sheath, and bioptome manipulation. The current study evaluates the feasibility and utility of real‐time transthoracic three‐dimensional echocardiography (3DE) to guide right ventricular endomyocardial biopsies in children. Methods: From July 2003 to April 2004, we utilized real‐time 3DE in 28 consecutive cardiac catheterizations in children aged 18 months to 16 years who were undergoing endomyocardial biopsy. A commercially available 3DE scanner (Philips Sonos 7500) equipped with a 2–4 MHz 3D matrix array transthoracic probe was utilized in all cases. Results: A total of 123 endomyocardial biopsy samples were obtained in nine patients (BSA 0.85 m2± 0.33 m2). Of these 123 samples, 99 (80%) were obtained with the use of real‐time transthoracic 3DE. There were no complications, including no new tricuspid valve leaflet flail or pericardial effusion. 3DE proved to be a reliable noninvasive modality to properly direct the bioptome to the desired site of biopsy within the right ventricle. As familiarity with this technique increased, the need for fluoroscopic guidance of bioptome manipulation in the right ventricle was minimized. Conclusions: The use of real‐time transthoracic 3DE in endomyocardial right ventricular biopsies in children is both feasible and safe. Further study to determine the impact of real‐time 3DE guidance on fluoroscopy and case times for endomyocardial biopsies is warranted.

Right Ventricle-to-Pulmonary Artery Shunt: Alternative Palliation in Infants With Inadequate Pulmonary Blood Flow Prior to Two-Ventricle Repair

BACKGROUND Traditional palliation of infants with biventricular hearts and inadequate pulmonary blood flow is a modified Blalock-Taussig shunt. The aim of this report is to assess the results of an alternative, right ventricle-to-pulmonary artery (RV-PA) shunt. METHODS Between August 2004 and July 2007, 10 infants with biventricular hearts and inadequate pulmonary blood flow underwent palliation with an RV-PA shunt. Median age was 9 days (range, 4 to 86), weight was 3.0 kg (1.7 to 4.5), and 4 of 10 patients weighed less than 2.5 kg. Shunts were nonvalved Gore-Tex (W.L. Gore Assoc, Flagstaff, AZ), and size was 6 mm (n = 5) or 5 mm (n = 5). RESULTS There were no operative deaths. Median oxygen saturation at hospital discharge was 95% (87 to 98). In 2 patients the shunt was partially narrowed with a metal clip; they underwent successful balloon dilation 6 months after shunt placement. Eight patients have undergone two-ventricle repair 6 to 17 months after shunt placement. At the time of complete repair, oxygen saturation was 86 +/- 1% and weight was 7.7 +/- 1.7 kg. Repairs included a valved RV-to-PA conduit, 14 to 16 mm in diameter. There was one interstage death. CONCLUSIONS The RV-PA shunt provides successful palliation in infants with biventricular heart disease and inadequate pulmonary blood flow. It can be used in low birth weight infants and allows significant growth with protection of oxygen saturation prior to complete repair. Partial clipping of the shunt with subsequent balloon dilation is an option to prolong palliation. These results compare favorably with those of a modified Blalock-Taussig shunt or single stage complete repair.

Impact of pre-stage II hemodynamics and pulmonary artery anatomy on 12-month outcomes in the Pediatric Heart Network Single Ventricle Reconstruction trial.

OBJECTIVE To compare the interstage cardiac catheterization hemodynamic and angiographic findings between shunt types for the Pediatric Heart Network Single Ventricle Reconstruction trial. The trial, which randomized subjects to a modified Blalock-Taussig shunt (MBTS) or right ventricle-to-pulmonary artery shunt (RVPAS) for the Norwood procedure, demonstrated the RVPAS was associated with a smaller pulmonary artery diameter but superior 12-month transplant-free survival. METHODS We analyzed the pre-stage II catheterization data for the trial subjects. The hemodynamic variables and shunt and pulmonary angiographic data were compared between shunt types; their association with 12-month transplant-free survival was also evaluated. RESULTS Of 549 randomized subjects, 389 underwent pre-stage II catheterization. A smaller size, lower aortic and superior vena cava saturation, and higher ventricular end-diastolic pressure were associated with worse 12-month transplant-free survival. The MBTS group had a lower coronary perfusion pressure (27 vs 32 mm Hg; P<.001) and greater pulmonary blood flow/systemic blood flow ratio (1.1 vs 1.0, P=.009). A greater pulmonary blood flow/systemic blood flow ratio increased the risk of death or transplantation only in the RVPAS group (P=.01). The MBTS group had fewer shunt (14% vs 28%, P=.004) and severe left pulmonary artery (0.7% vs 9.2%, P=.003) stenoses, larger mid-main branch pulmonary artery diameters, and greater Nakata indexes (164 vs 134, P<.001). CONCLUSIONS Compared with the RVPAS subjects, the MBTS subjects had more hemodynamic abnormalities related to shunt physiology, and the RVPAS subjects had more shunt or pulmonary obstruction of a severe degree and inferior pulmonary artery growth at pre-stage II catheterization. A lower body surface area, greater ventricular end-diastolic pressure, and lower superior vena cava saturation were associated with worse 12-month transplant-free survival.

Effect of Preoperative Use of Propranolol on Postoperative Outcome in Patients With Tetralogy of Fallot

The aim of this study was to determine if preoperative propranolol therapy has a deleterious effect on postoperative variables in patients with tetralogy of Fallot. Data from 97 patients who underwent complete repair of tetralogy of Fallot were reviewed. The patients were divided into 2 groups: those receiving preoperative propranolol therapy (n = 32) and those not receiving therapy (n = 65). Preoperative and intraoperative variables did not differ between groups. There were no differences in postoperative inotrope scores on arrival to the intensive care unit and through the first 12 hours postoperatively. There was a trend toward increased inotrope scores at 24 hours (median 8 vs 5, p = 0.05) and 48 hours (median 8 vs 3, p = 0.05) postoperatively in the patients treated with propranolol. Temporary pacing in the early postoperative period occurred more often in the propranolol group (16% vs 3%, p = 0.04). There was no difference between groups in length of mechanical ventilation, intensive care unit stay, or total hospital postoperative stay. In conclusion, propranolol therapy can be used in patients with tetralogy of Fallot until the time of surgery, without important effects on their postoperative courses. Any blunting of inotropic or chronotropic activity in propranolol-treated patients appears to be easily overcome with increased inotropic medications or temporary pacing, without increased morbidity or mortality.

Transseptal Left Heart Catheterization for a Patient With a Prosthetic Mitral Valve Using Live Three-Dimensional Transesophageal Echocardiography

The images and videos presented in this article illustrate a diagnostic transseptal left heart catheterization for a patient with a prosthetic mitral valve guided by live three-dimensional (3D) transesophageal echocardiography. This method provided high-quality 3D imaging that was useful in guiding transseptal puncture and demonstrating prosthetic valve function during this evaluation.

Characteristics of the Interatrial Communication in Patients Undergoing Transcatheter Device Closure of Atrial Septal Defects for Cryptogenic Stroke

Background: Prior studies suggest that patent foramen ovale (PFO) diameter >4 mm is associated with a high probability of cryptogenic ischemic stroke (CIS). Methods: We evaluated all patients diagnosed with CIS who underwent closure of intra‐atrial communication (IAC) using the Amplatzer atrial septal defect (ASD) occluder in our institution between August 1997 and March 2004. For each IAC, echocardiographic diameters and balloon‐stretched diameters were recorded. Stretchability index was calculated as the ratio of stretched diameter to unstretched diameter. Results: Fifty‐six patients met the inclusion criteria for this study. There was an inverse logarithmic relationship between unstretched IAC diameter and stretchability index. For the 28 smaller defects, the median IAC diameter was 2 mm, and median stretchability index was 5.58 (range 2.6–15). For the 28 larger defects, median diameter was 6 mm, and median stretchability index was 2.38 (range 1.05–5). The difference in stretchability index between the two groups was significant (P < 0.0001). Conclusion: Our data bring into question the concept that the diameter of the defect would singularly predict the probability of stroke.

Simplified Pulmonary Vasodilatory Testing in the Cardiac Catheterization Laboratory with Nasal Cannula Nitric Oxide

In patients with pulmonary hypertension, pulmonary vasodilator testing with inhaled nitric oxide (NO) during cardiac catheterization provides valuable data for defining future care plans. Previously, the use of delivery systems for spontaneously breathing individuals required a tight-fitting seal by face mask and an approved delivery and dilution device. We hypothesized that a simplified delivery system using nasal cannula could be utilized to effectively deliver NO during cardiac catheterization. We developed a simple delivery system to deliver through a nasal cannula a concentration of NO at 50 ppm at the nares along with supplemental oxygen (O2) via face tent. We prospectively employed this system for 10-minute intervals on 11 patients (age range, 7 months to 41 years) with pulmonary hypertension undergoing scheduled cardiac catheterization. Mean pulmonary artery pressure (PAp) decreased from 62 mmHg (range, 38–99) at room air testing to 45 mmHg (range, 36–91) with the addition of NO plus O2 (p = 0.014). Pulmonary vascular resistance (PVR) decreased from 11.6 U · m2 (range, 4.5–43.4) to 6.3 U · m2 (range, 2.0–34.2) (p = 0.001). A response of 20% or more reduction in PVR was seen in all 11 patients. The initial ratio of pulmonary to systemic vascular resistance (Rp:Rs) was 0.49 (range, 0.25–3.5) and decreased to 0.35 (range 0.1–2.6) (p = 0.002). No adverse side effects were noted. We found this NO delivery system to be a simple and effective method of pulmonary vasodilatory testing that may have wide applicability in the cardiac catheterization laboratory.