The Western Thoracic Surgical Association

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Risk Factors for Complications of Cardiac Surgery in Patients with Noonan Syndrome
Pouya Hemmati, Joseph A Dearani, Richard C Daly, Katherine S King, Naser M Ammash, Frank Cetta, Hartzell V Schaff
Mayo Clinic, Rochester, MN

Background: There is a paucity of data on the outcomes of cardiac surgery in patients with Noonan syndrome. Our objective was to evaluate the early results in this patient population from a single institution.
Methods: Between Jan 1999 - Dec 2015, there were 29 patients (18 males, 62.1%) with Noonan Syndrome who underwent cardiac surgery at our institution. Mean age was 23±17.9 years; 12 (41.4%) were under 18 years of age. Primary diagnoses included pulmonary valve/conduit stenosis or regurgitation (n=15, 51.7%), obstructive hypertrophic cardiomyopathy (HCM) (n=8, 27.6%), aortic valve stenosis or regurgitation with aortopathy (n=4, 13.8%), and atrial septal defect (ASD) (n=2, 6.9%). Fourteen patients (48.3%) had at least one prior sternotomy.
Results: The index operations at our institution (n=29) were pulmonary valve/conduit replacement/repair (n=14, 44.8%), transaortic and/or transventricular septal myectomy (n=7, 24.1%; 2 were biventricular septal myectomies), aortic valve replacement/repair (n=4, 13.8%), and ASD closure (n=2, 6.9%). Cardiac transplantation was performed in 2 patients: one for atrioventricular canal defect with biventricular obstructive HCM, and the other for restrictive cardiomyopathy with pulmonary regurgitation. Concomitant (secondary) procedures were performed in 24 patients (82.8%) and included right ventricular outflow tract reconstruction (n=13, 44.8%), mitral valve repair/replacement (n=7, 24.1%), ASD closure (n=6, 20.7%), ascending aortic replacement (n=3, 10.3%), tricuspid valve replacement/repair (n=3, 10.3%), ventricular septal defect closure (n=2, 6.9%), and other operations (n=7, 24.1%). Mean cardiopulmonary bypass and cross-clamp times were 88.8±51 min and 54.7±67 min, respectively. There was one early death (3.4%). Postoperative complications occurred in 18 patients (62.1%) and included atrial (n=14, 44.8%) or ventricular (n=3, 10.3%) arrhythmias, respiratory insufficiency/pneumonia (n=6, 20.7%), and chylothorax (n=3, 10.3%). Two patients required early reoperation: one for sternal dehiscence and one for epicardial permanent pacemaker placement. As shown in Table 1, univariate risk factors associated with complications included male gender (p=0.03) and longer cross-clamp time (p=0.02). Median length of hospital stay was 6 days (maximum of 49 days). There were 4 patients (13.8%) readmitted within 30 days: one each for atrial fibrillation, ventricular tachycardia, gastrointestinal bleeding, and unspecified abdominal pain.
Conclusions: Indications for cardiac surgery in patients with Noonan syndrome frequently require addressing multiple lesions with a broad spectrum of operations. Early mortality is low despite procedure complexity. However, early postoperative morbidity is common in this younger population and is associated with longer cross-clamp times and male gender. Additional studies are needed to investigate long-term outcomes and quality of life.

Table 1: Pre- and Perioperative Factor Associations with Postoperative Complications
Postoperative Complication
Yes (N=18)No (N=11)p-Value*
Variables
Age (years)0.246
N1811
Mean±SD20.0±19.428.0±14.5
Age < 180.059
No8 (44.4%)9 (81.8%)
Yes10 (55.6%)2 (18.2%)
Gender0.032
Male14 (77.8%)4 (36.4%)
Female4 (22.2%)7 (63.6%)
Previous sternotomy0.201
No11 (61.1%)4 (36.4%)
Yes7 (38.9%)7 (63.6%)
Previous cardiac operation0.099
No9 (50.0%)2 (18.2%)
Yes9 (50.0%)9 (81.8%)
Cardiopulmonary bypass time (min)0.115
N1811
Mean±SD101.1±56.268.7±34.7
Cross-clamp time (min)0.022
N1811
Mean±SD74.9±77.421.6±21.2
* p-Values are from univariate logistic regression


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