ATS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Boulos Asfour
Ehrenfried Schindler
Andreas E. Urban
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Photiadis, J.
Right arrow Articles by Urban, A. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Photiadis, J.
Right arrow Articles by Urban, A. E.
Related Collections
Right arrow Congenital - cyanotic

Ann Thorac Surg 2006;81:976-981
© 2006 The Society of Thoracic Surgeons

Original article: Cardiovascular

Improved Hemodynamics and Outcome After Modified Norwood Operation on the Beating Heart

Joachim Photiadis, MD a , * , Boulos Asfour, MD, PhD a , Nicodème Sinzobahamvya, MD a , Christoph Fink, MD b , Ehrenfried Schindler, MD c , Anne-Marie Brecher, MD a , Andreas E. Urban, MD, FETCS a

a Department of Pediatric Thoracic and Cardiovascular Surgery, German Pediatric Heart Institute, Sankt Augustin, Germany
b Department of Cardiac Intensive Care, German Pediatric Heart Institute, Sankt Augustin, Germany
c Department of Anesthesiology, German Pediatric Heart Institute, Sankt Augustin, Germany

Accepted for publication September 15, 2005.

* Address correspondence to Dr Photiadis, Department of Pediatric Thoracic and Cardiovascular Surgery, German Pediatric Heart Institute, Arnold Janssen-Strasse 29, D-53757, Sankt Augustin, Germany (Email: photiadis{at}gmx.de).


   Abstract
Top
 Abstract
Introduction
 Patients and Methods
 Results
 Comment
 References
 
BACKGROUND: Recently introduced cardiopulmonary bypass techniques to avoid circulatory arrest were proposed to improve organ function of the modified Norwood operation for hypoplastic left heart syndrome. This study compares postoperative hemodynamics and survival in patients who underwent Norwood procedure on the beating heart to those operated on with cardioplegic cardiac arrest.

METHODS: Between October 2002 and January 2005, 26 consecutive patients aged 4 to 275 days (median, 9 days) and weighing 2.9 to 4.4 kg (median, 3.4 kg) underwent Norwood palliation: 13 with continuous coronary and systemic perfusion (group 1), and 13 with only continuous systemic perfusion but arrested heart (group 2). Standard hemodynamic measurements, lactate levels, arterial and superior vena cava oxygen saturations, and inotropic agents required for postoperative hours 0, 6, 12, 18, 24, and 48 were retrospectively analyzed. For univariate comparison of different variables, {chi}2 test, Fisher's exact test, or Student's t test was used as appropriate.

RESULTS: In group 1 significantly higher mean arterial pressure (53 ± 0.8 versus 50 ± 1.2 mm Hg; p = 0.04), higher central oxygen saturation (54% ± 1.1% versus 50% ± 1.5%; p = 0.03), higher urinary output (5.3 ± 0.4 versus 4.4 ± 0.4 mL · kg–1 · h–1; p = 0.09), lower lactate levels (2.4 ± 0.1 versus 4.1 ± 0.6 mmol/L; p = 0.009) with lower doses of norepinephrine (0.03 ± 0.004 versus 0.14 ± 0.03 µg · kg–1 · min–1; p = 0.002) were recognized. Hospital mortality was 0% in group 1 and 38.5% (5 of 13) in group 2 (p = 0.04). Univariate analysis revealed mortality to be also correlated with preoperative intubation (p = 0.02) and the use of preoperative inotropic agents (p = 0.03).

CONCLUSIONS: Avoidance of cardiac arrest by means of continuous coronary perfusion in addition to continuous systemic perfusion significantly improves postoperative hemodynamic performance and thus helps to reduce hospital mortality after the modified Norwood procedure.


   Introduction
Top
 Abstract
 Introduction
Patients and Methods
 Results
 Comment
 References
 
Staged reconstructive surgery pioneered by Norwood and colleagues [1] is currently the treatment of choice for hypoplastic left heart syndrome in most centers, especially in view of neonatal donor heart shortage. Hypothermic circulatory and cardioplegic cardiac arrest are generally used for first-stage palliation (modified Norwood operation). With improved surgical techniques and better understanding of management of parallel circulations, mortality of modified Norwood operation has fallen to approximately 10% to 20%. The remaining mortality is thought to correlate with inadequate systemic oxygen delivery caused by an imbalance of pulmonary to systemic blood flow ratio or low cardiac output. With balanced pulmonary to systemic blood flow ratio, preservation of ventricular and end-organ function becomes the key interest to improve stage I outcome. Like others, we adopted continuous monitoring of central venous oxygen saturation to control pulmonary to systemic blood flow ratio balancing [2] and a technique of aortic arch reconstruction without circulatory arrest to preserve end-organ function in all patients.

To better preserve myocardial function, we extended the concept of end-organ perfusion to the heart and introduced the modified Norwood operation with the beating heart at our institute. We retrospectively compared hemodynamic status and outcome of infants undergoing Norwood procedure on the beating heart with infants operated on with cardioplegic cardiac arrest.


   Patients and Methods
Top
 Abstract
 Introduction
 Patients and Methods
Results
 Comment
 References
 
Patients and Operative Conduct
Between October 2002 and January 2005, 26 consecutive patients underwent modified Norwood operation without circulatory arrest for hypoplastic left heart syndrome or complex forms of single ventricle with systemic outflow obstruction. Twenty-one patients received an infusion of prostaglandin E1 to maintain ductal patency before surgery, 8 needed preoperative mechanical ventilation, and 2, inotropic support. Patient demographics are displayed in Table 1. Perioperative management and surgical conduct for all patients included appropriate preoperative stabilization, patch augmentation of the aortic arch using pulmonary homograft material, and placement of a modified Blalock-Taussig shunt (n = 19; diameter, 3.5 to 5 mm) or right ventricular to right pulmonary conduit (RV-PA shunt [3], n = 7; diameter, 5 to 6 mm; Gore-Tex, W.L. Gore & Associates, Inc, Flagstaff, AZ). For continuous systemic perfusion a shunt (3.5 to 5 mm) was sewn to the innominate artery in all patients. Patients were cooled on full-flow cardiopulmonary bypass (120–150 mL · kg–1 · min–1) to a nasopharyngeal temperature of 18°C. Phentolamine (0.5 to 3 mg/kg) was administered to facilitate cooling and rewarming. Once 18°C core temperature was attained, the left carotid and subclavian arteries and the descending aorta were clamped, and aortic arch reconstruction was performed. During reconstruction of the aortic arch, lower body perfusion was monitoring by an additional arterial catheter placed in the femoral or umbilical artery, and the pump flow was adjusted (40 to 80 mL · kg–1 · min–1) to achieve a mean lower body arterial pressure around 10 mm Hg.


View this table:
[in this window]
[in a new window]
  		Table 1. Patient Demographics a
 
Definition of Groups
Patients were operated on concurrently and assigned to either group 1: operation performed on beating heart, or to group 2: operation conducted with cardioplegic arrested heart, according to the surgeons' preference and irrespective of diameter of ascending aorta, diagnosis of aortic atresia, or preoperative hemodynamic status (Table 1).

Group 1: Beating heart
Thirteen patients were operated on using the beating heart protocol. In 6 patients the ascending aorta was not enlarged, and coronary perfusion was established using flow from the innominate artery with an aortic cross-clamp at the level of the proximal arch for aortic augmentation (Fig 1A [4]). In 7 remaining patients, coronary perfusion (5 to 10 mL · kg–1 · min–1) was established using a 4F cannula (DLP Medtronic, Düsseldorf, Germany) inserted in the ascending aorta just above the sinotubular junction. The ascending aorta was cross-clamped just above the cannula, and patch augmentation of the ascending aorta and arch was undertaken (Fig 1B). In all patients, coronary overperfusion and cardiac distension was prevented by monitoring of atrial pressure and reduction of coronary perfusion flow, if mean atrial pressure exceeded approximately 2 mm Hg.


Figure 1
View larger version (32K):
[in this window]
[in a new window]
  		Fig 1. Schema of the two techniques used for continuous coronary perfusion. (A) Continuous coronary and systemic perfusions are applied through a Gore-Tex tube (diameter, 3.5 to 5 mm) retrograde to the ascending aorta and antegrade to the carotid and subclavian arteries supplying the upper body, and through collaterals to the lower body. The aorta ascendens is not augmented. (B) Continuous coronary perfusion is established through a 4F cannula. Continuous systemic perfusion is instituted via a Gore-Tex tube connected to the brachiocephalic artery. The ascending aorta is augmented. (AA = reconstruction of aortic arch by anastomosis of the pulmonary artery to the undersurface of the aortic arch with homograft patch augmentation of only the posterior aspect of the aortic arch [in A], and by using a homograft patch augmentation on the anterior and posterior aspect of the aortic arch [in B]; CCP = continuous coronary perfusion; CF = collateral blood flow; CSP = continuous systemic perfusion; PA = main pulmonary artery.)

 
Group 2: Cardioplegic arrested heart
In 13 patients continuous systemic perfusion by means of the modified Blalock-Taussig shunt was instituted, and once core temperature of 18°C was reached, the heart was arrested by means of application of crystalloid cardioplegia (St. Thomas II). Coronary perfusion was recommenced after homograft patch augmentation of the arch and ascending aorta and the atrial septectomy were completed.

Perioperative Management for Both Groups
Standard atrial septectomy was performed through a small right atriotomy during a short period of low-flow cardiopulmonary bypass. Venous blood was removed from only the right atrium, to avoid systemic air embolism. Before closure of the right atriotomy was completed, air was removed from the right heart using normal saline solution. Cardiopulmonary bypass flow was slowly increased after removing the clamps from the descending aorta, and thereafter, from the left subclavian and left carotid artery. Subsequently, the patient was rewarmed on full-flow bypass. The heart was assisted with partial cardiopulmonary bypass as long as necessary to achieve serum lactate levels below 4 mmol/L and normal sinus rhythm. Modified ultrafiltration was always applied. Rarely, sequential atrioventricular pacemaker stimulation was instituted before the patient was weaned from cardiopulmonary bypass.

Postoperative Management
All patients received dopamine (4 to 6 µg · kg–1 · min–1). Milrinone and norepinephrine were added, if deemed necessary. Pulmonary to systemic blood flow ratio, calculated using the Fick method, assuming a pulmonary venous saturation of 97%, was adjusted between 1 and 1.5. Oxygen excess factor, which has been shown to correlate with systemic oxygen delivery [5], was calculated as arterial oxygen saturation divided by the difference between arterial and central venous oxygen saturations. Indexed pulmonary blood flow (oxygen consumption divided by {0.136 multiplied by hemoglobin in g/dl times [97% minus arterial oxygen saturations]}), indexed systemic blood flow (oxygen consumption divided by {0.136 multiplied by hemoglobin times the difference between arterial and central venous oxygen saturations}), cardiac index (indexed pulmonary blood flow plus indexed systemic blood flow), and systemic vascular resistances were calculated using oxygen consumption derived from standard formulas. After removal of the oximetric catheter, the left to right shunt was estimated according to clinical signs of heart failure, and afterload reduction therapy with carvedilol (0.1 to 1.2 mg · kg–1 · d–1) and captopril was initiated if required.

Hemodynamic Data Collection and Statistical Analysis
A prospective perioperative database for all Norwood patients was established including demographic, surgical, and postoperative hemodynamic and laboratory data. Informed consent was obtained from patients' parents for data collection and statistical analysis for study purposes, in accordance to national laws. Hemodynamic measurements, systemic arterial and venous oxygen saturations, serum lactate, and doses of medications administered were analyzed at 0, 6, 12, 24, and 48 hours after admission to the intensive care unit, or until commencement of extracorporal membrane oxygenation (n = 2) or the patient's death. Data were summarized as mean ± standard error of the mean. For analysis the {chi}2 analysis, Fisher's exact test, or Student's t test was used, as appropriate.


   Results
Top
 Abstract
 Introduction
 Patients and Methods
 Results
Comment
 References
 
Preoperative Conditions and Surgical Variables
There were no significant differences in the preoperative conditions such as age, weight, use of inotropic agents, and intubation, or in complexity of the procedures calculated by means of the comprehensive Aristotle score [6], or other surgical variables (Table 1), except for aortic cross-clamp times, attributable to the different perfusion techniques in the two groups.

Hemodynamic Variables
Lactate levels already during cardiopulmonary bypass tended to be lower in group 1 and were significantly lower during the first 48 hours postoperatively (p = 0.009). Reviewing the entire postoperative period from hour 0 to hour 48, mean arterial blood pressure and central venous oxygen saturation were recorded as higher (p = 0.04; p = 0.03, respectively) with lower doses of norepinephrine (p = 0.002) in group 1 (Table 2). Also, higher urinary output (p = 0.09) despite lower doses of furosemide (p = 0.04) was recognized for group 1. No significant differences were noted for doses of milrinone and phentolamine between the groups.


View this table:
[in this window]
[in a new window]
  		Table 2. Patients' Postoperative Hemodynamics a
 
Significantly higher arterial oxygen saturation (p = 0.04) and calculated pulmonary blood flow (p = 0.04) with lower fraction of inspired oxygen (p = 0.03) were found in group 1. Pulmonary to systemic blood flow ratio was adjusted between 1 and 1.5 in both groups according to our protocol. Arteriovenous oxygen difference and oxygen excess factor were not significantly different between the groups, indicating similar systemic oxygen delivery.

Blalock-Taussig and right ventricle–to–pulmonary artery shunt patients had no significant differences in systemic and venous oxygen saturations, arteriovenous oxygen saturation difference, or oxygen excess factor during the first 48 hours.

Outcome
There were five deaths, representing 19% (5 of 26; 95% confidence interval, 6.6% to 39.3%). Causes of death were low systemic oxygen delivery or low cardiac output, despite aggressive inotropic therapy. No arrhythmia that required treatment and no electrocardiographic evidence of myocardial ischemia were noted in these patients. In one patient extracorporeal membrane oxygenation was initiated 18 hours after surgery but was discontinued because of cerebral bleeding 42 hours after surgery. Significant differences in hospital mortality were noted between groups: 0% (0 of 13; 95% confidence interval, 0% to 24.7%) in group 1 and 38.5% (5 of 13; 95% confidence interval, 13.9% to 68.4%; p = 0.04) in group 2. Significant risk factors for death assessed by univariate analysis are displayed in Table 3. They include, in particular, preoperative ventilation (p = 0.02), preoperative inotropic agents (p = 0.03), higher comprehensive Aristotle score (p = 0.01), and lower central venous oxygen saturation and higher lactate levels (Table 3).


View this table:
[in this window]
[in a new window]
  		Table 3. Univariate Risk Factor Analysis for Hospital Mortality a
 
All hospital survivors are still alive or reached second-stage palliation, except for one in group 1, who died unexpectedly 3 months after surgery. Postmortem examination did not reveal shunt thrombosis or stenosis as a cause of death.


   Comment
Top
 Abstract
 Introduction
 Patients and Methods
 Results
 Comment
References
 
Patients with hypoplastic left heart syndrome have poor forward output through the aorta. Coronary perfusion is marginal and dependent on retrograde flow from the patent ductus arteriosus. Moreover, differences of the immature neonatal myocardium regarding cytoarchitecture, biochemistry, and physiology enhance susceptibility to damage during cardiopulmonary bypass, aortic cross-clamping, and reperfusion [7].

The technique used during stage I reconstruction has to focus on establishing optimal vision to create an unobstructed systemic ventricular outflow tract, but similarly on maintaining the limited myocardial reserve of the single ventricle supplying the systemic and pulmonary circulation. Measures that decrease myocardial oxygen consumption by means of hypothermic cardiopulmonary bypass and selective coronary perfusion resulted in superior outcome after repair of hypoplastic or interrupted aortic arch [8].

This study demonstrates a better early postoperative outcome when coronary perfusion is continued during modified Norwood operation. This is highlighted by lower lactate levels in perioperative and postoperative period, superior postoperative hemodynamic status, renal function, and pulmonary performance. Like Bradley and colleagues [9], we did not recognize significant differences regarding hemodynamic status and oxygen delivery comparing Blalock-Taussig and right ventricle–to–pulmonary artery shunt patients. Thus, improved outcome may be attributed to a better preservation of myocardial function. This is in keeping with results of Kishimoto and associates [10]. Unfortunately, these authors did not carry out hemodynamic studies.

Univariate analysis revealed hospital mortality to be associated with preoperatively existing poor condition, necessitating ventilation and inotropic agents, and with application of cardioplegic cardiac arrest during stage 1 reconstruction. With optimal preoperative management ensuring good preoperative condition, and with the application of continuous coronary and systemic perfusion, there was no hospital mortality in our cohort. This underlines the importance of prenatal diagnosis of hypoplastic left heart syndrome allowing prospective therapy planning, resulting in improved stage 1 survival [11].

In conclusion, the reported technique of continuous coronary perfusion in addition to systemic perfusion during modified Norwood operation is easily applied, allows excellent vision, offers unrestricted time for accurate aortic arch reconstruction (which is essential for long-term outcome of the single ventricle circulation), and is associated with superior postoperative hemodynamic status and improved survival. It should be used in all patients with hypoplastic left heart syndrome, except for those in whom correction of associated defects commands the use of cardiac arrest.


   References
Top
 Abstract
 Introduction
 Patients and Methods
 Results
 Comment
 References
 

  1. Norwood WI, Lang P, Hansen DD. Physiologic repair of aortic atresia-hypoplastic left heart syndrome N Engl J Med 1983;308:23-26.[Medline]
  2. Tweddell JS, Hoffman GM, Fedderly RT, et al. Phenoxybenzamine improves systemic oxygen delivery after the Norwood procedure Ann Thorac Surg 1999;67:161-167.[Abstract/Free Full Text]
  3. Sano S, Ishino K, Kawada M, et al. Right ventricle-pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome J Thorac Cardiovasc Surg 2003;126:504-510.[Abstract/Free Full Text]
  4. Asfour B, Fink C, Sinzobahamvya N, et al. Modified Children's II operation on the beating heart allows growth potential Ann Thorac Surg 2005;80:e14-e16.[Abstract/Free Full Text]
  5. Charpie JR, Dekeon MK, Goldberg CS, Mosca RS, Bove EL, Kulik TJ. Postoperative hemodynamics after Norwood palliation for hypoplastic left heart syndrome Am J Cardiol 2001;87:198-202.[Medline]
  6. Lacour-Gayet F, Clarke D, Jacobs J, Comas J, Aristotle Committee The Aristotle scorea complexity-adjusted method to evaluate surgical results. Eur J Cardiothorac Surg 2004;25:911-924.[Abstract/Free Full Text]
  7. Karimi M, Wang LX, Hammel JM, et al. Neonatal vulnerability to ischemia and reperfusioncardioplegic arrest causes greater myocardial apoptosis in neonatal lambs than in mature lambs. J Thorac Cardiovasc Surg 2004;127:490-497.[Abstract/Free Full Text]
  8. Karl T, Sano S, Brawn W, Mee RB. Repair of hypoplastic or interrupted aortic arch via sternotomy J Thorac Cardiovasc Surg 1992;104:688-695.[Abstract]
  9. Bradley SM, Simsic JM, McQuinn TC, Habib DM, Shirali GS, Atz AM. Hemodynamic status after the Norwood procedurea comparison of right ventricle-to-pulmonary artery connection versus modified Blalock-Taussig shunt. Ann Thorac Surg 2004;78:933-941.[Abstract/Free Full Text]
  10. Kishimoto H, Kawahira Y, Kawata H, Miura T, Iwai S, Mori T. The modified Norwood palliation on a beating heart J Thorac Cardiovasc Surg 1999;118:1130-1132.[Free Full Text]
  11. Tworetzky W, McElhinnney DB, Reddy VM, Brook MM, Hanley FL, Silverman NH. Improved surgical outcome after fetal diagnosis of hypoplastic left heart syndrome Circulation 2001;103:1269-1273.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Ann. Thorac. Surg.Home page
A. Mo, H. Lin, Z. Wen, W. Lu, X. Long, and Y. Zhou
Efficacy and Safety of On-Pump Beating Heart Surgery
Ann. Thorac. Surg., December 1, 2008; 86(6): 1914 - 1918.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
A. D. Cochrane
Invited commentary
Ann. Thorac. Surg., March 1, 2006; 81(3): 981 - 981.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Boulos Asfour
Ehrenfried Schindler
Andreas E. Urban
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Photiadis, J.
Right arrow Articles by Urban, A. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Photiadis, J.
Right arrow Articles by Urban, A. E.
Related Collections
Right arrow Congenital - cyanotic

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS