Okan Yildiz

Early Degeneration of Extracellular Matrix Used for Aortic Reconstruction During the Norwood Operation

The use of prosthetic patch material is often required during the surgical reconstruction of complex congenital cardiac malformations. Decellularized porcine small intestinal submucosa, a type of extracellular matrix, was recently introduced as a patch for cardiac and vascular tissue repair. Extracellular matrix was used for aortic reconstruction during the Norwood procedure in 8 consecutive neonates with hypoplastic left heart syndrome. Rapid degeneration or aneurysm formation developed in 3 of these patients who came to second-stage surgery. Extracellular matrix should be used cautiously for aortic reconstruction in infants until additional reports from other centers provide confirmation of its safety.

Hemodynamics of patient-specific aorta-pulmonary shunt configurations

Optimal hemodynamics in aorta-pulmonary shunt reconstruction is essential for improved post-operative recovery of the newborn congenital heart disease patient. However, prior to in vivo execution, the prediction of post-operative hemodynamics is extremely challenging due to the interplay of multiple confounding physiological factors. It is hypothesized that the post-operative performance of the surgical shunt can be predicted through computational blood flow simulations that consider patient size, shunt configuration, cardiac output and the complex three-dimensional disease anatomy. Utilizing only the routine patient-specific pre-surgery clinical data sets, we demonstrated an intelligent decision-making process for a real patient having pulmonary artery atresia and ventricular septal defect. For this patient, a total of 12 customized candidate shunt configurations are contemplated and reconstructed virtually using a sketch-based computer-aided anatomical editing tool. Candidate shunt configurations are evaluated based on the parameters that are computed from the flow simulations, which include 3D flow complexity, outlet flow splits, shunt patency, coronary perfusion and energy loss. Our results showed that the modified Blalock-Taussig (mBT) shunt has 12% higher right pulmonary artery (RPA) and 40% lower left pulmonary artery (LPA) flow compared to the central shunt configuration. Also, the RPA flow regime is distinct from the LPA, creating an uneven flow split at the pulmonary arteries. For all three shunt sizes, right mBT innominate and central configurations cause higher pulmonary artery (PA) flow and lower coronary artery pressure than right and left mBT subclavian configurations. While there is a trade-off between energy loss, flow split and coronary artery pressure, overall, the mBT shunts provide sufficient PA perfusion with higher coronary artery pressures and could be preferred for similar patients having PA overflow risk. Central shunts would be preferred otherwise particularly for cases with very low PA overflow risk.

Left coronary artery stenosis causing left ventricular dysfunction in two children with supravalvular aortic stenosis.

Congenital supravalvar aortic stenosis (SVAS) is an arteriopathy associated with Williams-Beuren syndrome (WBS) and other isolated elastin gene deletions. Cardiovascular manifestations associated with WBS are characterized by obstructive arterial lesions such as SVAS and pulmonary artery stenosis in addition to bicuspid aortic valve and mitral valve prolapse. However, coronary artery ostial stenosis may be associated with SVAS, and it increases the risk of sudden death and may complicate surgical management. In this report, we present our experience with two patients having SVAS and left coronary artery ostial stenosis with associated left ventricular dysfunction.

Assessment of children with vascular ring

Vascular rings may cause pressure on the trachea and/or esophagus of varying degree, resulting in symptoms. This study assessed the presentation symptoms, diagnostic methods and treatment results after surgery in children with vascular ring.

The use of neonatal extracorporeal life support in pediatric cardiac intensive care unit.

Abstract Aim: The aim of the study is to evaluate extracorporeal life support system (ECLS) employed in neonates in pediatric cardiac intensive care unit. Material and methods: Twenty-five neonates that required ECLS in between November 2010 and November 2015 were evaluated. Results: The median age was 12 days (range 3–28 days) and the median body weight was 3 kg (range 2.5–5 kg). Venoarterial ECLS was performed in all of the cases. Ascendan aorta-right atrial cannulation in 22 patients and neck cannulation in three patients were performed. The reason for ECLS was E-CPR in two patients, inability to wean from cardiopulmonary bypass (CPB) in seven patients, respiratory insufficiency and hypoxia in nine patients, low cardiac output (LCOS) in seven patients. Median duration of ECLS was four days (range 1–15). Hemorrhagic complications developed in 15, renal complications in 13, pulmonary complications in 12, infectious complications in 11, neurologic complications in three and mechanical complications in two of the patients. Weaning was successful in 15 of the patients. Eleven patients were successfully discharged. Conclusion: ECLS is an important treatment option that is performed successfully in many centers around the world to maintain life support in patients unresponsive to medical treatment. The utilization of this modality especially in newborns with congenital heart disease should be taken into consideration.

Extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest in children after cardiac surgery.

Objective: Extracorporeal membrane oxygenation (ECMO) is used to provide cardiorespiratory support during cardiopulmonary resuscitation (extracorporeal cardiopulmonary resuscitation; ECPR) unresponsive to conventional methods. In this study, the results of ECPR in a cardiac arrest setting after cardiac surgery in children were analyzed. Methods: In this retrospective cohort study, between November 2010 and June 2014, 613 congenital heart operations were performed by the same surgical team. Medical records of all the patients who experienced cardiac arrest and ECPR in an early postoperative period (n=25; 4%) were analyzed. Their ages were between 2 days and 4.5 years (median: 3 months). Sixteen patients had palliative procedures. In 88% of the patients, cardiac arrest episodes occurred in the first 24 h after operation. Mechanical support was provided by cardiopulmonary bypass only (n=10) or by ECMO (n=15) during CPR. Results: The CPR duration until commencing mechanical support was <20 min in two patients, 20–40 min in 11 patients, and >40 min in 12 patients. Eleven patients (44%) were weaned successfully from ECMO and survived more than 7 days. Five of them (20%) could be discharged. The CPR duration before ECMO (p=0.01) and biventricular physiology (p=0.022) was the key factor affecting survival. The follow-up duration was a mean of 15±11.9 months. While four patients were observed to have normal neuromotor development, one patient died of cerebral bleeding 6 months after discharge. Conclusion: Postoperative cardiac arrest usually occurs in the first 24 h after operation. ECPR provides a second chance for survival in children who have had cardiac arrest. Shortening the duration of CPR before ECMO might increase survival rates. (Anatol J Cardiol 2017; 17: 328-33)

Surgical repair of true left ventricular aneurysm in an infant: a rare complication after unsuccessful perventricular VSD closure.

A 2.5-month-old female patient presented for closure of a ventricular septal defect (VSD). Transthoracic echocardiography showed a large muscular ventricular septal defect. After perventricular closure of the defect was performed with an Amplatzer muscular VSD occluder, peroperative transesophageal echocardiography revealed that the device had been implanted in the wrong area of the ventricular septum. The device was retrieved and a large mid-muscular defect with extension to the outlet septum was closed with a patch of Dacron which was secured with 5-0 sutures. A perforation in the ventricular septum due to attempted perventricular device delivery was seen, and it was repaired primarily. In the eighth month of follow-up, transthoracic echocardiography revealed an aneurysm in the posterior wall of the left ventricle. The patient’s electrocardiogram showed pathological Q waves and ST-segment elevation in leads DII, DIII, and aVF consistent with subacute inferior myocardial infarction. At subsequent surgery, this was found to be a true aneurysm, located in area of distribution of the obtuse marginal branch of the left circumflex coronary artery in the posterior wall of the left ventricle. The aneurysm was closed off using a Dacron patch, and the sac was resected. Development of a true aneurysm is a rare but important complication of attempted perventricular VSD closure.

Vacuum-Assisted Closure for Mediastinitis in Pediatric Cardiac Surgery: A Single-Center Experience

Vacuum-assisted closure (VAC) has been widely used to treat mediastinitis after congenital cardiac surgery, which is associated with a high risk of morbidity and mortality. The aim in this study is to review our 14 cases of mediastinitis treated with VAC therapy after congenital cardiac surgery. We retrospectively reviewed the medical records of 14 congenital heart patients with mediastinitis from January 2012 to March 2017. Patients with fever, wound discharge, sternal dehiscence, a positive wound culture or abscess diagnosed with computed tomography are accepted as mediastinitis. A VAC was applied to all our patients without irrigation or dressing the wound because of sterility concerns. The vacuuming of the wound was either 50 mm Hg or 75 mm Hg according to the sternal intactness. We gradually decreased the pressures and changed the VAC systems once every three days, after wound healing was seen and a negative culture was obtained and VAC was terminated. There were 14 patients (8 male and 6 female) with mediastinitis and all of them were treated using VAC. The mean age of the patients was 6.96 months (ranging from 0.5-26 months). The mean weight was 5.16 kg (2.8-12 kg). Three patients needed extracorporeal membrane oxygenation after the surgery. Mean onset of mediastinitis was 25.3 days. The wound cultures showed methicillin resistant coagulase negative streptococcus and methicillin-sensitive staphylococcus aureus in most cases. Acinetobacter, serratia, pseudomonas, and klebsiella were the other bacterial species seen in cultures. Two patients had mediastinitis symptoms, but their cultures were negative. VAC systems were changed 3.85 times on average. Mean duration of hospital stay was 49.9 days (21-104 days). One patient needed a muscle flap to close the thoracic cavity after mediastinitis. Two patients did not survive. Mediastinitis is a serious postoperative condition in pediatric cardiac surgery patients. Classical wound dressing and irrigation methods are not suitable in mediastinitis for the pediatric age group. Therefore, VAC therapy can be an effective way to successfully treat the situation.

Alterations in antioxidant and oxidant status of children after on-pump surgery for cyanotic and acyanotic congenital heart diseases.

OBJECTIVE Oxidative stress refers to an imbalance between reactive oxidative species and antioxidants. In this case-controlled, prospective, observational study, we investigated the total oxidant status, total antioxidant status, oxidative stress index, and albumin and C-reactive protein levels of children with cyanotic and acyanotic congenital heart diseases who had undergone on-pump cardiac surgery. METHOD The study groups consisted of 60 patients with congenital heart disease, who were operated under cardiopulmonary bypass, and a control group of 30 healthy individuals. The patients were classified into two groups. Among them, one was a patient group that consisted of 30 patients with acyanotic congenital heart disease and the other group consisted of 30 patients with cyanotic congenital heart disease. In the patient groups, blood samples were collected before surgery and at one and 24 hours following surgery. In control groups, blood samples were collected once during hospital admission. RESULTS No statistically significant differences were found between the groups in terms of baseline total oxidant status, total antioxidant status, and oxidative stress index values. Regarding the postoperative first-hour and 24-hour total oxidant status and total antioxidant status levels as well as oxidative stress index values, there were no significant differences between the groups, except for an increase in total antioxidant status levels (p=0.002) 24 hours after surgery in cyanotic patients. CONCLUSION There was no difference between oxidative stress status of cyanotic and acyanotic congenital heart disease patients and healthy individuals. Oxidative stress status of cyanotic and acyanotic patients does not change after cardiac surgery under cardiopulmonary bypass.

The Efficacy of Thoracic Ultrasonography in Postoperative NewbornPatients after Cardiac Surgery

Objective In this study, the efficacy of thoracic ultrasonography during echocardiography was evaluated in newborns. Methods Sixty newborns who had undergone pediatric cardiac surgery were successively evaluated between March 1, 2015, and September 1, 2015. Patients were evaluated for effusion, pulmonary atelectasis, and pneumothorax by ultrasonography, and results were compared with X-ray findings. Results Sixty percent (n=42) of the cases were male, the median age was 14 days (2-30 days), and the median body weight was 3.3 kg (2.8-4.5 kg). The median RACHS-1 score was 4 (2-6). Atelectasis was demonstrated in 66% (n=40) of the cases. Five of them were determined solely by X-ray, 10 of them only by ultrasonography, and 25 of them by both ultrasonography and X-ray. Pneumothorax was determined in 20% (n=12) of the cases. Excluding one case determined by both methods, all of the 11 cases were diagnosed by X-ray. Pleural effusion was diagnosed in 26% (n=16) of the cases. Four of the cases were demonstrated solely by ultrasonography, three of them solely by X-ray, and nine of the cases by both methods. Pericardial effusion was demonstrated in 10% (n=6) of the cases. Except for one of the cases determined by both methods, five of the cases were diagnosed by ultrasonography. There was a moderate correlation when all pathologies evaluated together (k=0.51). Conclusion Thoracic ultrasonography might be a beneficial non-invasive method to evaluate postoperative respiratory problems in newborns who had congenital cardiac surgery.